US2919002A - Selection mechanism for a single printing element typewriter - Google Patents

Description

Dec. 29, 1959 L. E. PALMER 2,919,002

SELECTION MECHANISM FOR A SINGLE PRINTING ELEMENT TYPEWRITER Filed April 19, 1957 9 Sheets-Sheet 1 www Dec. 29, 1959 L. E. PALMER 2,919,002

SELECTION MECHANISM FOR A SINGLE PRINTING ELEMENT TYPEWRITER Filed April 19, 1957 9 Sheets-Sheet 2 FIG. 3 :g3g 14 i m f V Si my ,l l 15 ii is, 26

Dec. 29, 1959 L. E. PALMER 2,919,002

SELECTION MECHANISIVI FOR A SINGLE PRINTING ELEMENT TYPEWRITER Filed April 19, 1957 esmas-sheets FIGA YCODE CHART v 2 3# 411 5% 6@ 781 8 111 R-5 R-4 R+4 R+5 R-5. R-4 R+4 TO TO TO TO T1 T1 T1 9( o) 1/14 I; In R+5 R+4 R+4 R+5 R-4 R-5 R-3 T 1 T 2 T3 T 3 T 2 T2 T1 2 1 o A bB c C d D e E R-3 R+3 R O R+I R-3 R+2 R O TO T 2 T2 T2 T 2 T2 TO f F gG h H i I J k K l L R-2 R+2 R+1 R- 1 R-3 R+2 R+1 T2 T3 TO T1 T3 T1 T1 mM nN oO pP qQ rR- SS R2 R-I R O R+1 R+3 R-1 R1 T I T O T 3 T3 T 3 T3 T 2 I T u U v V w W x X y Y Z Z RO R-2 R+3 R+2 R+3 R-2 R+3 T1 TO TO TO T 1 T 3 T 2 El TP R-4 R-5 T 3 T 3 DEGREES 360=I CYCLE 16 `49 82 115 14.7 180 213 246 278 311 344 KEYLEVER BAIL CYCLING INTERPOSER BAIL INTERPOSER HORIZONTAL SELECTOR LATCH SELECTOR CAMS PRINT CARRIER ESCAPENIENT Dec. 29, 1959 L. E. PALMER 2,919,002

SELECTION MECHANISM FOR A SINGLE PRINTING ELMENT TYPEWRITER Filed April 19, 1957 9 sheets-sheet 4 Dec. 29, 1959 L. E. PALMERl SELECTION MECHANISM FOR A SINGLE PRINTING ELEMENT TYPEWRITER 9 Sheets-Sheet 5 Filed April 19. 1957 Dec. 29, 1959 l.. E. PALMER 2,919,002.

SELECTION. MECHANISM FOR A SINGLE PRINTING LMENT TYPEWRITER Filed April 19, 1957 9 Sheets-Sheet 6 G 68 474 [467 m A ,#46 A D I B Dec. 29, 1959 L. E. PALMER SELECTION MECHANISM FOR A SINGLE PINTING ELEMENT TYPEWRITER Filed April 19, 1957 9 Sheets-Sheet '7 mom www

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Dec. 29, 1959 L. E. PALMER 2,919,092

SELECTION MECHANISM FOR A SINGLE PRINTING ELEMENT TYPEWRITER Filed Apri1 l9, 1957 9 Sheets-Sheet 8 9 Sheets-Sheet 9 wfw ar/Iliff L. E. PALMER SELECTION MECHANISM FOR A SINGLE PRINTING ELEMENT TYPEWRITER Filed April 19, 1957 United States Patent O SELECTION MEcHANIsM Fon A SINGLE PRINTING ELEMENT TYPEWRITER Leon E. Palmer, Lexington, Ky., assignor to International Business Machines Corporation, New York, N.Y., a corporation `of New York Application April v19, 1957, Serial No. 653,806

Claims. (Cl. 19716) This invention relates to typewriters and more particularly to an improved selecting mechanism for a single elementprinting head. v

The type of machine to which reference is made is one havmg a single element printing head wherein all of the characters of a type font are located on the surface of one printing device, which device may be positioned for prmtmg engagement with 4a paper carrier with a selected character of the type font in printing position.

Briey stated, a character is selected by tilting and rotating a single element printing head in response to depression of one of a plurality of key levers, each key lever being assigned to a character on the printing head. The key levers selectively actuate a displacement mechanism having two principal portions, one for tilting and another for rotating the printing head. More specifically, selecting links are operated which determine the pivot points of connecting members to produce an output of predetermined displacement and direction. In each portion of the displacement mechanism, the value of the output isr determined by the links selected either singly or in combination. When the links are selected in combination, the displacement is the sum of the individual displacements of the links. A tape and pulley mechanism couple the displacement mechanism to the printing head to locate the selected character in a reference position. Thereafter, the head is caused to strike the platen to print the chosen character.

It is a iirst object of this invention to provide an improved mechanism for selecting a character on a single printing element head in response to the operation of a key lever.

It is an object of this invention to provide a single element printing head selection mechanism having the facility of adapting the mechanism for remote control by addressing each character in terms of a small number of selecting elements.

Itis another object of this invention to provide a selecting mechanism for a single element typewriter wherein a uniform key lever force triggers a power operated selection device.

.in earlier single element typewriters, impact noise from clutches and other selective coupling members was at a high level. Accordingly, it is an object of this invention to provide an improved, quiet selecting mechanism.

It is a still further object of this invention to provide an improved indexing mechanism having an output link movable in increments in two directions in response to actuation by selected ones of a plurality of input links operated singly and in combination.

it is another object of this invention to provide a single clement typewriter having an improved case shift mechanism.

It is another object of this invention to provide a displacement mechanism having a plurality of actuating elements, an output mechanism, and a linkage mechanism ,connecting the actuating elements and the koutput mech- ICC anism for moving the output mechanism in incremental amounts and multiples thereof in response to operation or' the actuating elements singly and in combination respectively.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose by way of example, the principle of the invention and the best mode which has been contemplated of applying that principle.

In the drawings:

Figure 1 is a front elevation of the displacement mechanism and the single element printing head.

Figure 2 is a view of the single element printing head, partly in section.

Figure 3 is a diagrammatical view of the upper hemisphere of the printing shell. l

Figure 4 is a code chart for a typewriter keyboard'.

Figure 5 is a top plan view of a typewriter mechanism, partly in section.

Figure 6 is a side section of the mechanismtaken along the lines 6-6 of Figure 5.

Figure 7 is a section of the cycling clutch taken along the lines 7-7 in Figure 5.

Figure 8 is a diagrammatical view of the rotation selecting links.

Figure 9 is a diagrammatical illustration of the action of a reversing link.

Figure 10 is a side view of the shift mechanism.

Figure lll is a section of the shift clutch and cam taken along the line ill-11 of Figure` 10.

Figure 12 is a diagrammatical view of the pulley and tape system for rotating the printing head.

Figure 13 is a diagrammaticalview of thepulley and tape system for tilting the printing head.

Figure 14 isa mechanicaltiming chart.

Figure 15 is a side View of the line spacing drive Vmech-v anism taken along the line 15g-.15 of Figure 5..-

Figure 16 is` a section of the spacingclutch taken alongthe line 16-16 of Figurel5.

Figure 17 is a section of the spacingclutch taken along.

the line 1,7-17 of Figure 16.

In Figures 1 and 2, .thereis shown asingle element printing head l0 having a truncated spherical shell 11 with characters 12 arranged in rows `and columns about its peripheral surface. A printing head of this, type.` is` described in copending application patent Seriall No. 547,481, tiled November 17, 1955.

With particular reference to, Figure 3,v there is shown` a diagrammatic representation of the upper'half of the shell 11. Thel arrangement of characters is arbitrary, buty for the purposes of illustration, the lower case alphabetic characters are arranged in quadrants I and IV andthe upper case alphabetic characters are arranged inquadrants Various otherv characters, such as numbers-` II and III. and symbols, lill they remaining spaces on vthe head. Further, the rotational reference or home position` is ,chos-L en to be along the radial through the lower casee. Iny

each row, in quadrants I and IV, there areeleven columns,

live on each side of the home position e. Therefore,

for selection` of anyY of the aforementionedk teny columns, the head need be rotated clockwise or counterclockwise. from one to live units, Where one unit is equivalent to.` a

column.

Referring to Figure 2, the uppermost row isthe tiltp. home position, andk any character may be selectedfronr. a column by tilting the head 1, 2, or 3 units where-oneunit: is equivalent toa row of characters. For example,y

, tilted one unit.

to the reference position formerly occupied by lower case .e, and the head is rotated in increments of one to ve units clockwise or counterclockwise and tilted one to three units for selection of any character in those quadrants. By Way of example, to position upper case X the head is rotated 180 degrees, rotated three units clockwise, and It will be noted from the description thus far that it is possible to select any character by combinations of 180 degrees rotation, clockwise or counter-` clockwise rotation in increments of 1 through 5, tilting movement in increments of l through 3 and the absence of movement in any of the directions of motion. This makes control of the head possible with a small number of actuating elements used singly or in combination.

l In Figure 4, there is shown a code chart which illustrates the displacement required for each character on the shell 11. The uppermost characters in the blocks are those which usually appear on the key button of the ordnary keyboard with the right-hand character being the one which requires operation of the shift key in addition to operation of the selected character key. The R indicates rotation and the number adjacent thereto is the value in units of rotational movement required with clockwise rotation of the shell being assigned the arbitrary sign of plus for convenience of explanation, and counterclockwise rotation of the shell being assigned the minus sign as viewed in Figure 1. For example, lower case xl in the chart of Figure 4 shows three units of clockwise rotation and one unit of tilt.

In Figure 2, the printing element 10 is shown with the hollow shell 11 which is removably supported by a system of internal gimbals and bearings and held to the assembly by a screw 14. The center of mass of the sup porting mechanism is located substantially at the center of the truncated sphere to provide a uniform mass behind each print stroke, irrespective of the character being printed. Provision is made for rotating and tilting the printing element as described in detail with reference to Figures 1 and 5, in particular, in copending application Serial No. 547,481 referred to previously. For the purposes of illustrationV of the present invention, only the support and control members will be described.

A supporting tube 15 carries an integral base member to `support certain parts of the mechanism contained within the shell 11. A hollow tilt shaft is passed axially through the tube 15` and turning ofthe tilt shaft 20 causes tilting of the truncated shell 11 on which the characters are arranged. A tilt pulley 24 (Figures 2 and 5) is attached to the tilt shaft 20 and is turned in a manner to be explained subsequently.

A rotation pulley 25 (Figures 2 and 5) is connected to a turn shaft 26 (Figure 2) by a set screw 27. The turn shaft 26 is supported coaxially of the supporting tube 15 and lies Within the tilt shaft 20. The turning of the shaft 26 causes rotation of the truncated spherical shell 11.

With reference to Figure 6, there is shown the single element printing head 10 which traverses a platen 36 and prints successively in columns in normal printing fashion. The typehead 10 is supported on a carriage 38 which is movable on a shaft 39 and a bar 40 engaged by rollers 41, the platen 36 remaining stationary while the printing element moves across the sheet.

In Figure 6, the characters are selected by depression of the usual key levers 42 having their own key buttons 44. The key levers are pivotally supported about a xed rod 46 and each is biased upwardly by one of a plurality of springs 47. A pair of guide combs 48 and 49 position the key levers laterally and permit their pivotal motion abou the rod 46. Each of the key levers 42 supports an arm 50 which is pivotally connected to its respective key lever b'y a rivet 52, and biased clockwise by a spring 53 connected to an ear on the key lever. When a key lever is rocked cougztverclockwise, the arm 50 engages an interposer 55 of which there is one for each key lever. All of the interposers are pivotally supported about a xed rod 57 in such a manner that each interposer can be rocked about the rod 57 and moved transversely within the limits dened by a slotted opening 58. All of the interposers are positioned laterally and limited in an upward ly direction by a pair of guide combs 59 and 60, and each is limited in movement toward the rear of the machine by a shoulder 63 resting normally against a latch spring 61. A plurality of springs 65, one for each inter* poser and key lever respectively, couple the interposers to the key levers and bias the former toward the rear of the machine.

In Figure 5, six rods 70 through 75 are shown extended across the keyboard and perpendicularly aligned with the key levers. The portions of the rods beneath the interposers are offset from the ends, and the ends are rotatably supported in a pair of plates 78 and 79 which are attached to the base 80 of the machine. Thus, the

offset portions of the rods may be pivoted about their ends as shown more clearly in Figure 6.

With'reference to Figures 5 and 6 in particular, the interposer 55 has a plurality of projections 81, 82, 83, 84, 85, and 86 which are arranged to lengage the rods 70, 71, 72, 73, 74, and when the interposer is moved to- Ward the front of the machine. However, it is pointed out that' each interposer differs from the others by the particular projection or projections which it carries since each interposer is related to a character on the printing head and selects certain of the rods according to the desired displacement of the printing head. In the chart below, each character is listed with an X indicating the projections which are present on the related interposers to cause selection of the character.

INTERPOSER PROJECTION CHART 1 Interposer Projection Character Fte@ Hereafter, it will be understood that the number 55 for the interposer shown in Figure 6 refers to any of j the plurality of interposers as defined by the character associated therewith in the chart above.

With reference to Figure 5, there is shown a drive belt 901 whih .S Oltinuously driven by a motor and pulley (not shown) in a direction as indicated in the. drawing. The belt engages a pulley 91 whichis fixed to a shaft` 92 by a pin 93. The shaft 92 is journaled in bearings (not shown) supported in base members 80. A pair of collars 94 and 95 are connected to the shaft to limit its axial movement.

The shaft 92 and a shaft 96 coaxial therewith are selectively coupled by a friction-drive cycling clutch 97 of the helical spring type well known in the art. An end of the shaft 92- extends to the left of the collar 95 and is received Within a sleeve 98, and an end of the shaft 96 is received within the opposing end of the sleeve 98. A helical spring (not shown) surrounds the ends of the shafts 92 and 96 in a slide fit relation and is connected at its ends to the sleeve 98 and the shaft 96 respectively. In Figure 7 a latch 100 comprises a plate 101, a rectangular member 102 of resilient material, and an arm 103. The arm and the plate are bonded to the sides of the resilient member. The latch is pivotally mounted on a xed shaft 105 and is biased against a portion of the base 106 by a spring 107. Normally, the latch 100 engages a step on the sleeve 98 to prevent rotation of the latter. A rod 110 is connected to the latch 100 to release the sleeve when operation of the clutch is desired. A collar 112 having a notch 113 is fixed to the shaft 96 by a pin or set screw. A bracket 115 is mounted on a base member 116 and a detent arm 117 is pivotally mounted on the bracket 115 by a rivet 1118. The detent arm 117 is biased clockwise by a spring 120i, which extends between an end of the latch and a pin 122 on the base member 116. The detent arm 117 engages the notch 113 and thereby prevents clockwise rotation of the collar 112. The latch 100 and detent arm 117 are so located that the clutch spring is slightly unwound when the parts are in position as shown in Figure 7, and ac'- cordingly the shaft 96 is uncoupled from the shaft 92. When the rod 110 is moved to the left, the latch 100 is caused to pivot counterclockwise and disengage the plate 101 from the step on the sleeve 98. Due to the decrease in diameter of the clutch spring and the winding effect of the shaft 92, the spring winds tightly around the shaft 92 and the shaft 96. Thereafter, the shafts and the sleeve 98 rotate counter clockwise together until the step on the sleeve 98 engages the latch 100. Momentum carries the shaft 96 and collar 112 to the point where the detent arm 117 latches in the notch 113 and clutch spring is slightly unwound. At this time, the driven shaft 96 is again uncoupled from the driving shaft 92.

With reference to Figure 5, the Shaft 96 is journaled in a bearing in the base member 80 and extends therefrom sufficiently to accommodate a pulley which is attached to the shaft with a pin 131. A fluted shaft 133 is journaled in bearings mounted in the side plate 80 and extends through the left-hand side plates 80 a sufficient amount to accommodate a pulley 135 which is fixed to the uted shaft with a pin 136. Another pulley 137 (Figure 6) is fixed to the shaft 39 which guides the printing head carriage. A belt 138 engages the pulleys 130, 135 and 137 and is tensioned by an adjustable idler pulley 139. When the cycling clutch 97 is operated, the shafts 96, 133 and 39 are turned in the directions shown in Figure 6. However, it will be noted that shaft 133 makes one-half revolution while the print shaft 39 and the shaft 96 make one revolution.

ln Figure 1, there are shown ve selecting links 140, 141, 142, 143 and 144 of identical construction and only one will be described. In Figure 6, the selecting link has a foot 148 and an elongated slot 149, which is adapted to receivean end of a rod 150. The selecting link 140 is connected to a coupling element 152 compris-` ing a rivet 153 and a pair of members 154 and 155 having conically shaped faces which embrace a floating link 157 (Figure l) near its right end. With this connection, the link 140 may swing toward the keyboard as viewed in Figure 6, and the floating link 157 may pivot about the 6 pin 1.53'. The selectingy link 141 isconnected to another end of the lloating link y157-by a coupling element 158 of the same construction as the 'coupling element 152. As shown'in Figure l, one end of a link 159 is pivotally connected to `thefloating link 157 by a rivet 160 and the other end is pivotally connected to a floating link 1,62. The selecting link 142 is connected to the other end of the floating link 162 by a coupling element 164 of the type previously described. An end of a connecting link 165 is pivotally coupled to the floating link 162 by a rivet 16,6

and the other end of the link 1 65 is pivotallyv connectedy to a link 167 by a rivet 168. The right-hand end of thev link 167 is pivotally connected to a link 170 by a rivet 171. Pivotally mounted on the base by a fixed pin 172 is a bell crank 173 having an upper arm pivotally connected to the link 167 by a rivet 174 and a lower arm pivotally connected to a rod 176 by a rivet 177. In a manner to be described hereafter, the rod 176 is caused to moveto the left or right as viewed in Figure 1 in increments of one through five to cause rotation of the( printing shell.

The selecting link 143 is connected to a floating link 180 at a point near its right-hand end (Figure l) by a coupling element 181A of the type described, and the selecting link 144 is connected near the left-hand end of link 180 by another coupling element 181B. The lloating link 180 is pivotally connected to an end of a connecting link 184 by a rivet 184A, and another end of link 184 is connected to a crank arm 186 by a rivet 186A. In a manner to be describedlater, the crank arm 186 is caused to rock counterclockwise as viewed in Figure 1 by increments of one, two and three units to cause tilting of the printing head shell from its home position.

The right end of the floating link 157 is slidably received in a vertical slot in a bracket 190, which in turn is mounted on the base with a screw 190A. Similarly, a

bracket 192 is secured to the base by a screw 192A and slidably receives the left end of the floating link 157; a bracket 194 is secured to the base by a screw 194A and slidably receives the left end of floating link 162; a bracket 196 is secured to the base by a screw 196A and slidably receives the right end of the floating link 180; and a bracket 198 is secured to the base by a screw 198A and slidably receives the left end of the link 180. Each of the brackets described, limit the upward travel of the iioating links and guide the links as they are moved up and down. The floating links are biased upwardly to their limit of travel as determined by the brackets in a manner to be described subsequently.

To illustrate the principle of operation of the selecting links, reference is made to Figure 8. The link 170 remains immovable unless otherwise advised. When link 140 is selected, the crank 173 rocks two units; when link 141 is selected, the crank rocks one unit; and when link 142 is selected, the crank rocks two units. When two or more links are selected, the crank rocks a distance equal to the aggregate of the individually-caused displacements. By way of example, when link 140 is moved downwardly one inch ,the link 159 moves downwardly two-thirds of an inch since it is connected 273 X from the pivot point 158 of the link 157, and the link 165 moves downwardly 2/s of an inch since it is connected 3/s Y from the pivot point 164 of the link 162. When the link 141 is moved downwardly one inch, the link 159 moves one-third of an inch since it is connected 1/3 X from the pivot point 152 of the link 157, and the link 165 moves downwardly 1/5 of an inch since it is connected 3/s Y from the pivot point 164 of the link 162. When the link 142 moves downwardly one inch, the link 165 moves two-fifths of an inch, which is the same displacement that the link 165 would have if link 140 were selected. If both of the links 140, v142 are moved downwardly one inch, the link 159 moves two-thirds of an inch, the left-hand end 'of the link 162 moves one inch, and the link 165 movesl fourfths of an inch (four times the displacement due c 7 to actuation of the link 141 alone). Assuming that one unit of movement is one-fifth of an inch, it has been shown that 1, 2, and 4 units of output displacement can be produced. Similarly, coincident actuation of the links 141 and 142 produces a three unit output, and the actuation of the links 140, 141, and 142` produces a five unit output. Although certain values have been mentioned in this regard, it will be noted that the linkage may take many forms and have other dimensions, the lengths X and Y having any convenient value, and it is not intended that the invention be limited to the particular configuration. For example, the linkage could be arranged to have inputs of 1, 2, and 3 units instead of 1, 2, and 2 and accomplish the same result.

With link 170 immobile, it is apparent that the crank 173 is caused to move from rest, counterclockwise to one of five positions and then return to a neutral position as a bail oscillates selected links in a manner described hereafter. However, it is necessary for the crank to reverse its direction of motion to index the adjacent sector of the head. Accordingly, the arm 170 which is connected at the right end of the link 167 is held xed in the position shown to cause counterclockwise motion of the crank 173 and is moved upwardly by a predetermined amount to ca-use clockwise motion of the crank 173. This up- Ward movement of the link 170 is coincident with the` y downward movement of the link 165 to prevent a spurious movement of the crank. To explain this principle of operation, reference is made to Figure 9 where only the representation of the link 167 is shown with the rivets 168, 174, and 171 indicated for convenience of explanation. Normally, the link 167 is in a reference` position AB which corresponds to the position of the link 167 in Figures 1 and 8. Movement of the point 174 down causes counterclockwise rotation of the head and movement of the point 174 upwardly causes clockwise rotation of the head. To effect four units of counterclockwise displacement, the link 167 pivots about the point B (171) and assumes the position CB where the displacement of point 174 is from D to E. To produce one unit of clockwise displacement, the point 16S is moved from A to C as before while the point 171 is moved from B to F. It will be noted that the point 174 moves from D to G, which displacement is one-iifth of the counterclock- V Wise displacement D to E. Therefore, movement of point 171 from B to F has the eiect` of producing increments of movement at point 174 which arekthe complements of with respect to movement of point 174 when point B is held stationary. Accordingly, when selecting links 140 and 142 are operated in coincidence with movement of the arm 170, one unit (complement 5 minus 4) of clockwise displacement is produced at point 174. Likewise, if point 168 is moved from A to H by two units of displacement and point 171 remains at point B, the displacement of point 174 is from D to I which is equivalent to two units of displacement. When point 168 is moved from A to H by two units of displacement als be fore and point 171 is moved from B to F, the point 174 moves from D to I which is equivalent to three units (complement 5 minus 2) of clockwise displacement of the crank 173. From `the description thus far, it will be noted that point 171 need be moved only one distance (B p to F to cause clockwise movement of the crank 173 to any of the ve positions and that activation of link 170 (movement of point 171 from B to F) produces a ves complement output at point 174 when compared to movement of the crank 173 when link 170 remains stationary. The translation of the complement output is accomplished readily by arrangement of the projections on the interposers 55 and the rods 70-75 and is explained in detail subsequently.

With reference to Figure 5, there is shown a pair of cams 182A and 182B of identical contour ixed to the shaft 96 by pins 183A and 133B respectively. A. pair of arms 185A and 185B are pivotally connected to a shaft 187 which, in turn, is suitably supported in the base. Attached between the other ends of the arms is a bail 188, which is adjacent the foot on the selecting links 144 in their rest position as shown in Figure 6. Mounted on the arm 185A is a cam-follower roller 189A attached with a pin 189B, and mounted on the arm' 185B is another roller 189C (in Figure 5), each roller 189A and 189C following its respective cam 182A and 182B. A pair of springs 193 (Figure 5) bias the arms Iupwardly and keep the rollers in Contact with the cams. With lthe cycling clutch 97 latched up the cam followers 189A and 189C, are at the low dwell of the cam 182, so that the bail 188 is at its uppermost position. With this arrangement of parts, unlatching of the cycling clutch 97 causes the shaft 96 to revolve counterclockwise as viewed in Figure 6 and reciprocate the arms 185A and 185B and bail 188. When a selecting link such as link 140 is pivoted to the left (Figure 6) placing the foot 148 under the bail 188 and the cycling clutch is operated, the link 140 is drawn down as previously described with reference to Figure 8 and then returned to the rest position.

The operation of the link was explained in connection with causing clockwise motion of the crank 173, and the structure for controlling the link 170 will now be described. In Figure 5 a U-shaped member 191 is mounted at its open end on a collar 191A. The collar 191A is rotatably supported on the shaft 187 and is positioned along the shaft by a pair of collars 195. In Figure 6, a cam follower roller 197 is rotatably coupled between theparallel arms of the member 191 with a pin 197A, and a spring 196B (Figure 5) biases the member 191 and the roller 197 toward a cam 199, the latter being connected to the shaft 96 by means of a pin 199A. As shown in Figure 6, the arm 191 is coupled to the lower end of the arm 170 by means of a pair of discs 200A and B and a pin 200C. A bracket 201 (Figure 6) is suitably attached to the machine base and supports a pin 202. In Figure l, a sleeve 203 is rotatably supported on the pin 202 and is retained by a screw 204. In Figures 1 and 6 a link 205 is lsecured at an end of the sleeve 203, and another link 206 is secured to the other end of the sleeve. In Figure 6, a spring 207 is connected between the link 206 and the bracket 201 and normally biases the link toward the rear of the machine and against a stop pin 20S. In the normal position, the link 206 is engaging the stop pin and a foot of the link 205 is directly above a lip 191B on the member 191. In Figure l, a rod 209 is coupled to an end of the link 206, and when the rod is moved in a direction out of the paper (Figure l) the link 206, the sleeve 203, and the link 205 rock clockwise (Figure 6) causing the link 205 to move to the left and clear the lip 191B on the member 191.

With the cycling clutch 97 latched up, the cam 199 holds the member 191 in its lowermost position. When the cycling clutch is operated, the cam 199 begins to turn counterclockwise but the roller 197 and the member 191 move upwardly very slightly during the first few degrees due to the cut of the cam. With the link 205 in the normal position shown in Figure 6, the lip 191B of the member 191 bears against the link 205 and prevents the roller from following the cam. Accordingly, no effective motion is imparted to the arm 170 and rotation of the crank 173 is counter-clockwise (Figure l). When the cycling clutch 97 is operated and the rod 209 causes the reversing link 205 to rock clockwise out of the path of the member 191 (Figure l), the roller 197 follows the cam 199, the arm 170r moves upwardly, and the crank 173 turns clockwise as explained wtih reference to Figures 7 and 8.

With reference to Figure l, the output displacement for the rotation mechanism is taken from the rod 176.

A lever 211 is pivotally connected to a xed support 212 by means of a pin 213. The lower end of the lever is connected to the rod 176 and the upper end carries a pulley 214, which is mounted'fr rotation about a pin 215. A spring 216 extends between the lever 211 and a lixed pin 217 and biases the floating links 157 and 162 upwardly against the brackets 190, 192, 194. A ilexible tape 218 engages the pulley 214, and when the pulley is displaced according to the output of the rotation selection mechanism, the tape 218 causes rotation of the printing Snell 1l. The tape control system is sho-wn diagrammatically in Figure 12 to provide a better understanding of its operation and will be discussed in more detail later.

To tilt the printing shell il, the arm 186 is caused to rock by the movement of the link 184. In Figure 1, the arm 186 is connected at an end of a shaft 222 (Figure 5) with a screw 223 (Figure 1), and the shaft 222 (Figure is rotatably supported in a base member 224 and v a sleeve 225 secured to the latter. Connected to the other end of the shaft 222 is an arm 226 having a split hub which is arranged to clamp the shaft securely when a bolt 227 is tighened. As seen more clearly in Figurev 1, a bracket 228 is fixed to the machine base and rotatably supports a vertical shaft 229. Attached to the lower end of the shaft 229 with a screw 230 is a lever arm 231. Coupled to the arm 231 by a pin 232 is a link 233, which in turn is coupled ot the arm 226 with a pin 234. Attached to the upper end of the shaft 229 is a lever 235 (Figure 5) which is biased counterclockwise as viewed in Figure 5 by means of a spring 237 and a xed pin 238. Through the linkage just described, the floating link 180 is biased upwardly against the brackets 196 and 198. Operation of the tilt selection mechanism causes the arm 186, the shaft 222, and the arm 226 to move clockwise and the link 233 to move to the right as viewed in Figure l; and the arm 231, the shaft 229, and the arm 235 to turn clockwise as viewed in Figure 5. A pulley 240 is rotatably mounted on the lever arm 235 with a pin 241 and displacement of the center of the pulley 240 due to the motion of the lever 235 causes the printing shell 11 to tilt by a predetermined amount by means of a tape 243, a rotatable, fixed pulley 244, and the tilt pulley 24 (Figure 2). In Figure 13, the tape control mechanism is shown diagrammatically and will be discussed in more detail later.

As was pointed out and explained previously, the upper case characters are located on the quadrants II and III (Figure 3) and the characters thereon are selected by rotating the printing shell 180 degrees plus or minus the incremental rotation of the displacement mechanism. This 180 degree shift is caused by depression of the shift button 250 shown in Figure 10. With reference to Figure 5 and Figure 1l in particular, the continuously turning shaft 92 is supported in a bearing 252, which in turn is held in a support bracket 254 by means of members 255 and screws 256. A face cam 258 is rotatably mounted on the bearing 252 and is cut with an inclined contour as shown in Figure 5. A pair of notches 258A and B are arranged to engage the usual detent 259 in one or the other oft he cams stationary positions. The detent 259 is pivotable about a fixed pin 259A and is biased in the direction of the notch by a spring 259B. Attached near an end of the shaft 92 by a pin 260 is a sleeve 262 having notches spaced 90 degrees about its periphery. A dog 264 is pivotally mounted to the cam 258 by means of a pin 265 and washers 266 and is biased counterclockwise as viewed in Figure by a spring 267 attached between the dog and a pin 268 attached to the cam.

In Figure 10, the shift key button 250 is attached to a key lever 270, which is pivotable about a point near its extreme right-hand end (not shown) and is biased upwardly by a spring 272. An extension 274 of the key lever (Figures 5 and 10) embraces a crank 276, the latter being pivotally supported inthe -base members in,y bearings 278. As shown more clearly in Figure S, auy

an arm 280 is attached to the crank 276 with a pin 282. Pivotally mounted on a fixed stud 284 by a rivet 285 is an arm 286, one end of which is pivotally and slidably coupled to the arm 280 by a rivet 288 contained in a slot 286A (Figure 10). The other end of the arm 286 is G-shaped, having upper and lower portions 287A and 287B respectively which control the operation of the dog 264. As shown in Figure 10, the upper portion 287A normally engages the dog 264 and prevents the tooth of the latter from engaging one of the slots in the sleeve 262.

yIn Figure 10, there is shown an arm 289 which is pivotally connected to the support bracket 254 by a pin 289A. An opening 290 in the arm 2,89 receives a portion of a roller 291, Whichportion is arranged to extend from the arm 289 and engage a cam contour 296. A pair ofy bolts 298A and 298B secure a pair of arms 299A andv 299B each to one of the opposing surfaces of the arm 289, and the bolt 298A rotatably supports the roller 291 on the arm. A pulley 303 is rotatably mounted between the ends of the arms 299A and 299B by means of a rivet, and' the pulley supports the tape 218 as shown in Figure 1 and Figure 12.

For rotating the printing shell 11 to index the characters in quadrants Il and III, the shift key lever 270 is depressed and held down, and the crank 276 pivots clockwise causing clockwise rotation of the arm 280 to ythe dotted outline position in Figure l0. This in turn rocks the lever 286counterclockwise about the stud 284 and the upper portion 287A of the arm 286 releases the dog 264 which then drops into one of the slots in the sleeve 262. Since the shaft 92 is continuously rotating and the cam 258v is locked to the sleeve 262, the cam is rotated counterclockwise 18() degrees (Figure l0) until the dog 264 engages the lower arm 287B and is pulled from the notch of the sleeve 262. The cam roller 291 follows the cam contour and causes the arm 289 to move from left to right as viewed in Figure l, to its extreme right-hand position (shown in dotted lines) where it remains for so long as the shift key 25@ is held depressed. In Figure l2, this movement causes 180 degrees rotations of the head by means of the tape 218. At this time, operation of one of the character keys, for example, selects the upper case of that character from quadrants Il and Ill When the shift key is released, the lo-Wer portion 287B of the arm 286 releases the dog 264 allowing it to engage the sleeve 262, which in .turn causes rotation of the cam 258 until the dog is removed from the sleeve notch by the arm 287A in its lower position. In this manner, the arm 289 is moved from right to left to the normal position shown in Figure l, which is the lower case position.

Reference is made Ito Figure 1 Where the rod 150 is shown connected to the selecting link as previously described. A plurality of rods 292, 293, 294, 295 are individually coupled to the selecting links 141, 142, 143, 144 respectively in like manner and each extends from the connection described forward of the shafts 133 and 187 as shown in Figure 5. In Figure 5, the rod 209, which controls the direction of motion of the crank `173, is connected to a slide 300 by means of an adjustable pin clevis 301. A slot in the lower side of the slide 300 receives the rod 75. rI he control rod is connected to a slide 302 by an adjustable pin clevis 304, and a slot in the lower side of the slide 302 receives the rod 74 as shown in Figure 6. Similarly, .the rods292, 293, 294, 295 (Figure 5) are individually connected to slides 305, 306, 307, 308 respectively. A slot vin the slide 305receives the rod 73, and .in like manner the slide 306 is coupled to the rod 72, vtheslide 307-is coupled to the rod 71, and the slide 308 is coupled-to the rod 70. The

YDISPLAcaivil-:rrr CHART Rotate-plus Displacement 2 1 2 12 the member 191 for the first 30 degrees of shaft rotation due to the cut of the cams 182A,'182B and 199. Initially, when the cycling clutch is first operated, a ute on the shaft 133 (Figure 6) is only a few degrees from engaging the heel of the actuated interposer 55, which has been rocked clockwise into the path of the ute. After slight rotation of the shaft 133, the flute engages the heel of the interposer and drives it to the left (Figure 6). The

150 particular interposer operated is one which is arranged 302 305 306 10 to drive the rods 70, 71 and 74 (see the Rotate-Plus and PivOtROdS 74 73 -72 Tilt Displacement Charts) clockwise about their pivot points. With reference to Figure 5, this motion of the Rotate-minus Displacement 1 2 3 4 5 selecting link 140, 142, 205 14o, 141, 205 140, 205 141,205 205 Pull Rod 150, 293, 209 150, 292, 209 150, 209 202, 209 209 slide Blum-- 302, 306, 300 302, 305, 30o 302, 300 305, 30o 300 Pivot Rods 74, 72, 75 74, 73, 75 74, 75 73, 75 75 Tilt foregoing rods draws the slides 302, 307, and 308 and the pull rods 150, 294, and 295 (see the Displacement Displacement 2 1 Chart) toward the front of the machine and thereby engages the selecting links 140, 143 and 144 with the bail Selecting Link 143 144 188 (Figure 1). The bail 188 carries the selected links llllelgod g ggg to the bottom of its stroke, and at that time the rotation pivot ld 71 70 pulley 214 is displaced by a distance which causes plus two units (clockwise) of rotation of the printing shell by In the rotate-plus chart, the displacements shown are caused by the elements below the respective number. Displacements of 3 or 5 are caused by combinations of 2 and l or 2, 1, and 2 respectively.

In the rotate-minus chart, links are selected to give the desired complementary output as previously explained with reference to Figure 9. Thus, for example, .to have a minus one unit of displacement it is necessary to operate the links 140 and 142, which give four units in the plus condition, and also operate the reversing link 205. Since the output is the complement, the resulting movement of the crank 173 is one unit (minus) of displacement. To have a minus tive units of displacement, none of the selecting links need be operated since the complement of zero is ve, but the reversing link must be operated as indicated in the chart. It is pointed out that for a minus three units of displacement, the links 141 and 142 and their associated elements could have been used instead of the links 140 and 141 with the same result.

In the tilt chart, no additional explanation is necessary. It will be referred to in a later example of the operation of this device.

In Figure 6, a projection 309 on each of the interposers 55 is arranged to impinge upon a rod 310. The rod.310 engages a bell crank 312 which is pivotally mounted on a fixed bracket 313 with a pin 314, and the lower arm of the bell crank 312 is coupled to the rod 110 by means of an adjustable pin clevis 315. It will be remembered that the rod 110 engages the arm 100 of the cycling clutch (Figure 7) to disengage the latter and cause a clutch cycle.

To illustrate the operation of the device by example, assume that the g G key is depressed without operation of the shift key. To position the g on the printing shell at the reference position, the selector mechanism must produce an output of a plus 2 units of rotation and 3 units of tilting movement (Figure 4). In Figure 6, when the g key is depressed, its key lever 42 causes its arm 50 to engage its interposer 55 and rotate the latter clockwise about the rod 57. The crank rod 310 is caused to pivot counterclockwise which in turn causes clockwise movement of the bell crank 312. The lower end of the crank 312 draws the rod 110 to the left which causes the cycling clutch (Figures 5 and 6) to operate. At this time, the shafts 39, 96 and 133 begin to turn, but almost no motion is imparted to the selector bail 188 and way of the tape control system (Figure 12), and the tilt pulley 240 is displaced by an amount which causes the printing shell to tilt three units (Figure 13). While tilting and rotational movement of the printing shell have been described separately, it will be understool that the movements occur simultaneously. y

With the character selected, a cam 320 (Figure 6) mounted on the shaft 39 is now in a position where its high portion is immediately adjacent an end of a cam follower lever 321. The printing head post 15 is secured to a mounting member 323 by means of a collar 324 and screws 325. The mounting member 323 is pivotally mounted on a sleeve 326 and has an olset shoulder 323A pivotally coupled to another end of the lever 321 by means of a pin 328. A fulcrum rod 329 extends from the carriage frame 38 beneath the arm 321. After final positioning of the selected character on the shell, the largest radius of the cam 320 impinges upon the arm 321 causing the arm to pivot counterclockwise about the rod 329. This causes the member 323 to rock about the sleeve326 and engage the shell 11 with the platen 36 and print a g. The mechanical timing is illustrated in Figure 14;

As a further illustration of the operation of the de- Y, vice, assume that the c C key is depressed along with operation of the shift key. To position a C on the printing shell at the reference position, the selecting mechanism must produce an output of a minus three units of rotation and two units of tilting movement (Figure 4), and the printing shell must be rotated 180 degrees.V When the shift key is depressed (Figure l0), the crank 276 and the arm 280 rock clockwise pivoting the arm 236 counterclockwise, which releases the dog 264. The dog drops into one of the slots in the sleeve 262, which is continuously turning with the shaft 92. The cam 258 drives the cam follower 291 and the arm 289 to the right as viewed in Figure l. When the cam is rotated degrees, the dog 264 is removed from the slot by the arm 287B. At this time the arm 289 and the shift l pulley 303 are in the extreme right-hand position (Figure 1) which causes the shell 11 to rotate ISOdegrees placing the E in the'reference position. When the c C key is depressed, the cycling clutch 97 is operated in the manner previously kdescribed and interposer 55 for Vthe C key is rocked into the path of the flute on the shaft 133. 'Ihe interposer activated is one which is arranged to drive the rods 71, 74, and 75 (see the lnterposer Chart)` clockwise as viewed in Figure 6. With reference to the Rotate- Minus and Tilt Displacement Charts, these rods draw the slides 307, 302 and 300 and the pull rods 294, 150, 209 to the front of the machine tFigure and thereby engage the selecting links 140, and 143 with the bail 188 and remove the link 205 from the path of the member 191. The movement of the links 140, 143 and 205 cause a minus three units of rotation (counterclockwise) of the printing shell from the E reference position and two units of tilting movement which results in the movement of C to the reference position. Printing takes place in the marmer previously described. The mechanical timing is shown in Figure 14.

With reference to Figure 2, there is shown a clock spring 327 which is coupled at one end to the pulley 25 and at the other end to th'e carriage frame 38. The spring 327 is normally coiled in a state to exert a force tending to pull on the tape 218. In Figure 12, the tape 218 is connected to a fixed point 338 on the carriage frame 38, and when the lever 211 is caused to move from left to right by operation of the displacement mechanism, the spring 327 causes the pulley to turn counterclockwise taking up tape released by movement of the pulley 214. As previously described, the pulley 25 causes the head to rotate to the selected column. When the arm 211 is caused to move from right to left, the tape 218 causes the pulley 25 to turn against the spring resulting in clockwise rotation of the head to the selected column.

1n Figure 2, there is shown the pulley 24 and the tape 243 which engages the pulley track as shown in Figure 13. The end of this portion of the tape is xed to the pulley at a notch 328 shown in Figure 5, and a spring 329A is connected between the pulley and the carriage frame 38 as indicated in Figures 5 and 13. The spring is extended to bias the pulley counterclockwise and tends to pull on the tape 243. In Figure 13, the other end of the tape is connected to the carriage at the xed point 338 and, accordingly, counterclockwise movement of the arm 235 about the pin 241 releases tape which is taken by counterclockwi'se rotation of the pulley 24 due to the urging of the spring 329A. As explained previously, the head 10 is caused to tilt to the proper row of the selected character. i

Referring now to Figures l2 and 13, it will be noted that movement of the carriage 318 does not cause rotation and tilting of the printing shell 11 since both ends of each tape 218 and 243 are connected to the carriage and printing head assembly. It will be appreciated that the effective length of the tape remains constant during escapement and that no motion is transmitted to the pulleys.

ln Figure 5, there is shown a lcam 330 which is xed to me uted shaft 133 by means of a pin 332. Connected to the base member 80 is a shaft 334, which shaft supports a bell crank 336 shown more clearly in Figure 15.

Pivotally connected to an arm of the crank 336 by means of a pin 336A is a roller 340. The roller is biased into engagement with the cam 330 by means of a spring 342, which extends between the lower portion of the crank 336 and a xed pin 344. A rod 346 is connected to a slot 348 in the crank 336 by means of a pin clevis 350. As shown in Figure 5, the rod 346 is supported for sliding movement in a bracket 352, the latter being x'ed to a portion of the machine base (not shown).

In Figure 5, supported for pivotal movement about a xed pin 354 is a dog 356, which normally engages one of a plurality of teeth on a wheel 358. The dog 356 has a flange 360 which engages a side of an escapement member 362. The escapement member is pivotally mounted on the pin 354 and has a turned down tlange 364 normally in engagement with the dog 356. A spring 366 biases the dog and escapement member to their normal position relative to each other which is 'the position shown in Figure 5. A spring 367 is connected between theescapement member 362 and the base to bias the dog 356 into the wheel 358. The toothed wheel 358 is secured to a gear 368, and both wheel and gear'are mounted for rotation about a fixed shaft 370. A clock spring (not shown) couples the wheel 358 to the shaft in a manner biasing the wheelcounterclockwise as shown in Figure 5. With the dog 356 in engagement with the wheel 358, movement of the latter due to urging of the spring is prevented.

Referring now to Figure l5, operation of the cycling ciutch 97 (Figure 7) vcauses the shaft 133 to turn counterclockwise and a high lobe of the cam 330 to approach the' roller 340. In Figure 14 print time is shown to be at about 210 and thereafter, it is appropriate to move the carriage one letter space. Also shown is the start of the escapement which corresponds to the mechanical action of the high lobe of the cam 330 acting upon the roller 340. Ink Figure 15, the cam causes the crank 336 to rock clockwise about the shaft 3.34which movement drives the rod 346 to the right. In Figure 5, the rod impinges upon the flange 364 of the escapement member 362 causing. the latter to rock counterclockwiseabout the pin 354. The flange 364 bears against the dog 356 causing it to withdraw from the tooth of the wheel. A projection 372 on the escapement member 362 engages a tooth of the wheel 358 near the tooths point as the dog 356 is withdrawn from its respective tooth. Accordingly, when the wheel is free from the dog the clock spring (not shown) causes the wheel 358 to turn counterclockwise and the projection 372 on the escapement member 362 to move downwardly along the tooth, to a position of engagement with an adjacent tooth. In Figure 15, when the roller 340 passes the'high lobe of the cam 330, the rod 346 is caused to move to the left, whereupon, in Figure 5, the rod allows the dog 356 to engage the wheel as the escapement member 362 is moved clockwise. In this manner, the wheel 358 and gear 368 are moved one unit.

In Figure 5, a gear 374 engages the gear 368 and is rotatably mounted on a 'fixed pin 376. The gear 374 is secured to pulley 378 for rotation with the former upon movement of the wheel 358. A pulley 380 having a double track (not shown) is mounted for rotation about a xed pin 382, and a tape 384 passes about the track in the pulley 378I and the lower track of the pulley 380. On the leftside of the machine as shown in Figure 5, a pulley 386 is mounted for rotation about a xed pin 388, and a tape 390 is engaged with the track of the pulley 386, and with the upper track of the pulley 380, and is fixed to the carriage 38 with a clasp 392. With this arrangement of parts, the carriage is caused to move one letter space each time that the weel 358 is advanced one tooth space. As indicated in Figure 14, escapement is complete by the end of a machine cycle and the printing head 10 is positioned at the next adjacent printlng position.

Referring to Figure 15, there is Ashown a space bar 396, which is biased upwardly by a spring 398 and is attached to a lever 400. The lever 400 is pivotally mounted on the rod 46 and is positioned by the comb 48. A latch 402 is pivotally attached to the lever 400 with a rivet 404 and is biased counterclockwise about the rivet by means of a spring 406 extending between a projection on the latch 402 and a projection on the lever 400. An ear 408 on the latch 402 normally engages the top of the lever 400 due to action of the spring 406. An arm 410 is pivotally and slidably mounted on a rod 412 and is positioned by a guide 414. A detent 416 is pivotally mounted on the shaft 334 and bears upon an edge 4ofa notch 418 in a hub 420 of a cam 438. A spring 4722 extends between a projection on the detent 416 and an opening in the arm 410, and biases the latter to the right and clockwise as viewed in Figure 15. In the normal position, an -ear 424 on the arm 410 is directly below the latch 402. A portion of this arm 410 is shown in Figure 5. In Figure l5, the right-hand end of the arm 410 engages a projection on a wheel 426 to prevent rota- Vtion of the latter.

As previously described, the shaft 92 is continuously rotating, and, as viewed in Figure 15, rotates counterclockwise. As shown in Figures 16 and 17, a cylindrical member 428 is attached to the shaft 92 with a pin 430. The cylindrical member has teeth 432 (Figure 16) about the periphery of its portion of larger diameter (Figure 17), and its portion of smaller diameter is a bearing surface for the hub 434 of the wheel 426. The outer `surface of the hub 434 engages the hub 420 of the cam 438 in a slide tit so that the wheel 426 is movable with respect to the cam 438. A pin 440 is secured to the cam 438 and pivotally supports a dog 442. Normally, an end 446 of the dog bears against a pin 448, which pin is secured to and projects from the wheel 426. The other end of the dog 442 is coupled by a spring 450 to a pin 452 extending from the cam 438. A pin 453 on the dog 442 bears against the inner rim of the wheel 426 and the spring 450 is extended when the arm 410 holds the wheel in the position shown in Figures 15 and/16.

It is pointed out that since the detent 416 is holding `the cam 438 and the arm 410 is holding the wheel 426 so that the pin 448 engages the dog 442 and holds the latter in its extreme clockwise position, the cam 438 is not driven. However, when the space bar 396 is depressed, the latch 402 is carried downwardly by the lever 400 causing the arm 410 to turn counterclockwise. The end of the arm 410 is disengaged from the wheel 426, and the latter is free to turn counterclockwise due to the energy stored in the spring 450. The dog 442 turns counterclockwise about the pin 440 and a projection 455 engages a tooth 432 on the cylindrical member 428. Since the dog is attached to the cam 438 and the wheel -426 is coupled to the Cam by means of the pin 448 and the end 446 of the dog, the cam and wheel rotates counterclockwise. 456 and carries a pin 458, which pin pivotally supports a roller 460. As the cam 438 turns, the arm 454 rocks clockwise and moves a collar 462 to the right. The collar 462 is xed to the rod 346 with a pin 464 so that the rod is moved from left to right to cause a letter space as previously described. Due to the slot 348 in the crank 336 this movement of the rod does not cause movement of the arm 336. When the high lobe of the cam 438 passes the roller 460, the rod 346 moves from right to left and the escapement is completed as previously described.

When the arm 410 is pivoted out of engagement with the wheel 426 due to depression of the space bar, it moves to the right to the limit of the slot at the rod 412 due An arm 454 is pivotally mounted on a shaft` move from right to left-due to the wheel 426. As the space bar is releasedthe latch 402 is moved away from the arm 410 and pivots' into the normal position above the arm by action of thespring 406.

With reference to Figure 6, only one function of the latch 50 carried by the key levers 42 has been explained, namely, the function of actuating the interposer 55. In addition, the latch 50 prevents a repetition of character printing due to a single depression of a key lever. Upon depression of a key button 44, the key lever 42 carries the latch 50 downwardly to energize the interposer 55 and pivot the latter about the rod 57.l The tluted shaft 133 slides the interposer from right to left which carries the upper projection of the interposer past the lower horizontal surface of the latch 50. lf the key button is held depressed, the restoring movement of the interposer from left to right by the spring 65 causes the upper projection on the interposer to pivot the latch 50 counterclockwise and extend the spring 53. Accordingly, the interposer is not actuated a second time. When the key button is released, the latch 50 merely rocks into normal position due to urging by the spring 53.

While the invention has been explained with reference to a single printing element head 10 of the spherical shell type, it is pointed out that the invention may be practiced by those skilled in the art using other types of printing heads. Among others, it will be recognized that this invention is applicable to the prism-shaped type head v described in U.S. Patent No. 2,757,775, I. E. Hickerson.

to urging of the spring 422. This sliding movement ,i

moves the ear 424 of the arm from beneath the latch 402. Then, the action of the spring 422 urging the arm 410 clockwise causes the tail of the arm to move upwardly against the lever 400 and the other end of the arm 410 to move downwardly against the wheel 426. Thus, when the cam 438 makes a half revolution, the arm 410 engages another projection on the wheel 426, to cause the dog 442 to disengage from the tooth 455 by clockwise movement of the dog. Momentum of the cam 438 drives it to a point where the detent 416 drops into the opposing notch 418 and an escapement step is complete. It is pointed out that there are two high lobes on the cam 438, and two projections on the wheel 426 opposite each other so that an escapement occurs each half revolution of the cam and wheel. dog 442 is required to control each escapement since it is controlled by either projection on the wheel 426.

It will be noticed that if the space bar 396 is held depressed during the escapement cycle, a second escape- Vmentis prevented since the latch 402 is rotated clockwise l by the tail 424 of the arm 410 as the latter is caused to Only a single.

The invention may be used as an output device where the selecting links are actuated by solenoids in the manner well known in the art or by devices of similar purpose instead of the key levers as has been described heretofore. In such an arrangement, it is apparent that only a number of solenoids or like devices equal to the number of selecting links would beY required and that the use of key levers could be optional. For example, data on tape maybe easily coded in terms of the address required to select the proper characters on the printing head. Therefore, it is not intended that the invention be limited to key operation.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is: Y

1. In a printing machine having a printing head with a plurality of characters arranged thereon and operable to present one character at a time to a printing position, a plurality of operable means each associated with at least one said character, means responsive selectively to operation of said operable means for presentingselected said characters to said printing position, said selectively responsive means comprising an elongated link, a plurality of input members coupled to said link at points spaced there along and pivotable to an actuated position, an output member pivotally coupled to said link at a point intermediate said spaced points and movable therewith, means coupling said output member to said printing head for moving said head incrementally in accordance with incremental movement of said output member, means operable for moving said input members singly and in combination, in accordance with the operated one of said plurality of operable means, to said actuated position, and single means operable for displacing all said actuated input members wherebv said incremental movement of said output member, dependent upon the combination of said actuated input members, is effected.

2. The structure of claim 1 wherein said coupling means comprises a exible strand of predetermined length l? and'me'an's operable by said incremental movement of said output member for' incrementally shortening said strand whereby said headv is manipulated to present a selected character to said printing position. Y g

3. The structure of claim 2 wherein said last inentioned operable means comprises a pulley for peripheral engagement with said strand system and for pivotal movement radial to said strand system and proportional to said'incremental movement of said output member.

4. In a typewriter having a printing head with a plurality of characters arranged thereon and operable to present one character at al time to a printing position, a plurality of operable key levers each associated with at least one of said characters, means responsive selectively' toy operation of said key levers for presentin-g selected characters to said printing position, said means comprising a bail movable from a first position to a second position, a link, first and second input members pivotally coupled to said link at first and second points vrespectively and movable singly and in combination into engagement with said bail in response to operation of said key levers, an output member pivotally coupled to said link at a point spaced from said first and said second points and movable therewith, means coupling said output member to said printing head, and means for moving said bail and said engaged input members from said first position to said second position whereby said coupling means move said printing head an amount dependent upon the combination of said input members engaged with said bail.

5. A structure in accordance with claim 4 wherein said coupling means comprises a flexible strand normally having a uniform path length, means manipulating said head to locate the selected character in printing position in response to a change in path length of said strand, and means for varying the path length of said strand in response to movement of said output member.

6. A structure in accordance with claim 5 wherein said means for varying the path length of said strand comprises a pulley mounted for both peripheral engagement with said strand and for pivotal movement radial to said strand in response to movement of said output member.

7. In a typewriter having a single element printing head with a plurality of characters arranged thereon wherein only one character at a time may be located in a printing position, and having a plurality of operable key levers, each associated with at least one of said characters on said printing head, a selecting mechanism comprising, in combination, means operable to produce increments of displacement associated with each character with respect to the printing position, said means including at least one mechanism comprising a link, first and second input members arranged in parallel spaced relation and pivotally coupled respectively to said link at first and second points thereon, and an output member pivotally coupled to said link at a predetermined point with respect to said first and second input members; means actuating said displacement mechanism including selected ones of said first and second input members responsive to operation of a selected one of said key levers; and means including a flexible strand and pulley for manipulating said printing head responsive to said displacement mechanism.

8. In a typewriter having a single element printing head with a plurality of characters arranged thereon and operable to present one character at a time to a printing position and having a plurality of operable character key levers, each associated with at least one of said characters on said printing head, a selecting mechanism comprising, in combination, a bail reciprocable between first and second positions, first and second incremental displacement systems, each comprising a link, first and second input members arranged in parallel spaced relation and pivotally coupled respectively to said link at first and second points thereon, one of the input members of saidY second s'yvsvter'n beingfpiv'otallycouple'dfto tlzielinkiv in saidY first system at a point lfarther from'sa'id first -point than from said vsecond pointthereon, the other ofjsaidf inputmembers of said second system and'thejinput'mem" bers of said first system beingv selectively 4engageabl'e'with said bail in said first position and movable therewith to said second position, output meansv coupled'to said'linkv in said second system at a point farther from saidl first point than from said second point thereon, means selectively engaging said input members with said bail andV reciprocating said bail in response to operation of a selected one of said key levers, and means manipulating said printing head responsive to rsaid output means.

9. A structure in accordance withv claim 8 wherein said coupling means comprises a fiexible'strand normally havmeans for varying the path length of' said strand in `response to movement of said output member.

10. A structure in accordance with claim 9 wherein` said means for varying the path length of said strand comprises a pulley mounted for both peripheral engagement with said strand and for pivotal movement radialA to said strand in response to movement of said output member.

1l. In a typewriter having a single element printing head with a plurality of characters arranged thereon and operable to present one character at a time to a printing position and having a plurality of operable key 1eve'rs, each associated with at least one of said characters onl said printing head, a selecting mechanism comprising in combination first means operable to produce increments of displacement at its output associated with each char-y acter with respect to the printing position, said first means including at least one mechanism comprising a link, first and second input members arranged in parallel spaced re= lation and pivotally coupled respectively to said link at' first and second points thereon, and an output member pivotally coupled to said link at a predetermined point with respect to said first and second input members, and second means for producing increments of displacement in either of two directions in response to incremental inputs applied in the same direction when actuated by said first means comprising a link, means pivotally coupling the output member of said first means to said link, a control bar pivotally coupled to said link at apoint removed from the point at which said first input member is positioned, a second output member coupled to said link and movable thereby, said control bar being normally stationary in a first position so that said link of said second means and thereby said second output member is pivoted by said motion of said first output member in one direction in increments of displacement proportional to the increments of displacement imparted to said first output member, and means effective to move said control bar from said first to said second position with the application of inputs from said first means to render said incremental inputs efiective to move said link of said second means and thereby said second output member in a direction opposite to said first direction in increments of distance complementary to said input increment values applied to said first output member, means actuating said displacement means including said first and second input members responsive to operation of a selected one of said key levers, and fiexible strand means for manipulating said printing head responsive to said displacement mechanisrn.

l2. In a typewriter having a single element printing head with a plurality of characters arranged thereon wherein only one character at a time may be located in a printing position, a plurality of key levers movable from a rest position to an operating position, and a selecting mechanism for positioning a predetermined character in the printing position said selecting mechanism comprising, in combination, a flexible strand system having a` uniform path length While saidr key levers are in the res-t position, meansmaniplating said head to locate the selected character in printing position in response to change in path length of said -strand system, and means for varying the path length of said strand system in response to the operation of the key lever associated with the selected character, comprising rst and second incremental displacement systems each having a link, iirst and second input members arranged in parallel spaced relation and pivotally coupled respectively to said link at first and second points thereon, one of said input members of said second system being coupled to the link in said first system at a point farther from said first point than from said second point thereon, and output means coupling said manipulating means to said link in said second system at a point farther from said first point than from said second point thereon.

13. -In a typewriter, a single element printing head with a plurality of characters arranged thereon and operable to present one character at a time to a printing position, a plurality of operable character keys, each assigned to a first and second character of a pair of characters in predetermined spaced relation on said printing head, an operable control key, and a selecting mechanism comprising, in combination, a flexible strand system having a uniform path length when said key levers are not operated, first means varying the path length of said strand system in response to the operation of each of the character keys to locate its assigned iirst character in the printing position, and second means responsive to the operation of said control key to locate-the second character assigned `to the operated character key in printing position comprising an arm displaceableby a predetermined amount related to the space between said first and second characters of said pair, means coupling said arm and said flexible strand system, and cam means responsive to actuation by said control key to displace said arm,

' 14..A.claim inaccordance with claim 13 wherein said iirst means comprises a link, first and second input members arranged in parallel spaced relation and pivotally coupled to said link at rst and second points thereon, an output member pivotally coupled to said link at a predetermined point with respect to-said first and second input members, means actuating selected ones of said input members in response to movement of the operated character key, and means coupling said output member to said strand system for varying the path length of the latter.

15. In a typewriter having a printing head with a plurality of characters arranged thereon in a manner wherein only one character at a time may be located at a printing position and having a plurality of operable key levers, each associated with at least one of said characters on said printing head, a mechanism responsive to operation of a selected one of said key levers for locating its character in the printing position comprising, in combination, a cyclically operable bail reciprocable between first and second positions, a link, -rst and second input members arranged in parallel spaced relation and pivotally coupled respectively to said link at iirst and second points thereon and selectively engageable with said bail in said rst position and movable therewith to said second position, an output link pivotally coupled to said link at a predetermined point with respect to said yfirst and second input members, meanscoupling said output link to said printing head, and means selectively engaging said input members with said bail and reciprocating said bail in response to operation of the selected key lever.

References Cited in the le of this patent UNITED STATES PATENTS 2,320,810 Carroll lune l, 1943 2,684,745 Blodgett July 27, 1954 2,757,775 Hickerson Aug. 7, 1956 2,769,029 Howard Oct. 30, 1956

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