US3493091A - Print head shift mechanism - Google Patents

Description

1970 L. J. KAPP PRINT HEAD SHIFT; MECHANISM Original Filed Dec. 16, 1966 6 Shee ts-Shee t 1 Nl/EN 0 ZUDW/c; J. 164 PP Feb. 3, 1970 L. J. KAPP PRINT HEAD SHIP '1 MECHANISM 6 Sheets-Sheet 2 Original Filed Dec.

lNl ENTOR J KAPP Feb, 3., 1970 L. .LKAPP 3,493,091

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' PRINTHEAD SHIFT MECHANISM Original Filed Dec. 16, 1966 6 shets-sheet 4 JIIL] INVENTOR [Hall/l6 J- #41910 Feb. 3., 1970 Qriginal Filed '49 FIG.6

PRINT HEAD SHIFT MECHANISM Dec. 16, 1965 L. J. Km 3,493,091

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l l INVENTOR Feb. 3, 1970 L. J.:KAPP

FRINTflEAD SHIFT MECHANISM Original Filed Dec.

6 Sheets-Sheet 6 ZERO DEFL.

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IN VENTOR L UDV/G J. K APP MASTER CONTROL United States Patent Int. Cl. B41j 25/24, 1/32 US. Cl. 197-71 11 Claims ABSTRACT OF THE DISCLOSURE A mechanism which is operable to shift the elevation of a print head so that one of the twotype bands thereon will be moved into printing position. A pivoted arm is connected to a vertical shaft on which the print head is positioned.

The arm is pivoted to a raised or lowered position to bring one or the other of the two type bands into printing position by actuating either one of the two opposed solenoids located above and below the arm and on one side of the point at which it is pivoted. Acting together with the solenoids are two opposed springs which are connected to the other side of the pivot point. These springs are positioned so that when the arm is shifted from one position to the other by actuation of a solenoid, the spring opposite thereto will be stretched to store energy therein so that when the other solenoid is actuated, it will act together with that solenoid to bias the arm and thereby the print head to its new position.

This application is a division of application Ser. No. 603,330, filed Dec. 16, 1966, invented by Ludwig I. Kapp, and entitled Reed Operated Printer.

BACKGROUND OF THE INVENTION The invention relates to an improvement in printing mechanisms, and particularly to a novel means for shifting a print head so that one or the other of two type bands thereon is moved into operative printing position.

Prior art devices relied on a single mechanism to actuate an arm to raise and lower a type member between one of two printing positions. Solenoids and other such mechanisms were often employed, but since only one mechanism was used, the fatigue on this mechanism through constant operation would eventually result in its failure.

Applicant, on the other hand, has provided springs which work in conjunction with solenoids so that the longevity of the solenoids, and therefore the entire mechanism, will be significantly increased.

SUMMARY OF THE INVENTION A print head shifting mechanism is provided which comprises opposed solenoids working in conjunction with opposed springs for biasing an arm and thereby a print head which is interconnected thereto between first and second printing positions. As one solenoid is actuated, its opposed spring is stretched so that energy is stored therein. Then when the other solenoid is actuated, and the first solenoid is released, the energy in the spring acts to bias the arm and the print head to its new position.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-1A jointly show a front elevation of the machine embodying the invention.

FIG. 2 is a left side elevational view of the machine.

FIG. 3 is a plan view of the power reed and associated magnets as viewed along line 33 of FIG. 2.

FIG. 4 is a right side elevation of the printing unit.

FIG. 5 is a top sectional view taken along the line 5-5 of FIG. 4.

3,493,091 Patented Feb. 3, 1970 'FIG. 6 is a plan view of the printing unit.

FIG. 7 is a cross section elevation of the same taken on line 7-7 of FIG. 6.

FIG. 8 is an enlarged fragmentary plan view of the printing drum and aligner means therefor.

FIGS. 99A and 10 are graphic illustrations of an operation of the power device.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in particular to FIGS. 1-1A, the machine embodying the present invention comprises left and right side frames 1 and 2 having supported for rotation therein a non-shiftable work support platen 3. Forwardly within said frames is secured a transverse rod 4, while rearwardly of rod 4 said frames support a rail 5, which together serve to support for transverse movement a shiftable carriage C having mounted thereon the character printing drum 6, as hereinafter described.

Secured to the left side of said carriage by means of stud 7 is a flexible steel tape 8 which passes first around a pully wheel 9 pivotally mounted upon a bracket 10 fast to the left side frame 1, then across the front of the machine and around a pully wheel 11 rotatably supported upon bracket 12 secured to the right side frame 2, and subsequently is wound upon the drum 13 fast to the shaft 14 of a stepping motor 15. Fast also to motor shaft 14 is a second drum 16 on which is wound a similar tape 17, which passes around a pulley wheel 18 and is secured to the right side of the printing carriage C by means of stud 19. Thus in accordance with certain selective impulse signals, as received from any suitable control source or computer means in the well-known manner, motor 15 serves to displace printing carriage C selective distances either to the right or to the left.

Printing carriage C comprises a support frame 20 (FIGS. 4-7) the forward end of which. is slidable upon the rod 4 and the rearward end having rollers 21 for riding along the rail 5. Frame 20 is provided with a pair of upwardly extending trunnions 22 for receiving the pivot studs 23 fast within the bifurcated arms 24 forming the lower end of a U-shaped frame 24. Within the upper arm 24" of said frame is bearinged for rotation the upper portion of a shaft 25 upon which is fast the character or printing drum 6. If desired, drum 6 and shaft 25 may be a single piece, for instance, of molded nylon material. The lower end of shaft 25 is enlarged to form a socket for receiving the ball-shaped end 26 of a shaft 27 extending upwardly from a stepping motor 28 supported to the underside of the printing carriage frame 20. A pin 29 extends through ball 26 and is received by an elongated vertical slot 30 in the lower end of the printing drum shaft 25, whereby to effect drive connection thereof with the motor shaft 27 in manner to permit an upward and downward movement of the printing drum.

To efiect upward and downward movement of the printing drum, a pair of spaced rearwardly extending levers 31 are each pivotally mounted at 32 upon an upwardly extending portion 20' of the carriage frame 20. The rearward ends of each lever 31 are bifurcated to embrace the top and bottom sides of an enlarged circular disc 33, comprising a shoulder on the shaft 25. Mounted to extend between the pair of arms 31 for movement therewith, is a metal block 34 which said arms serve as an armature between two opposed magnets 35, 36 supported upon the frame portion 20' of the printing carriage C. With both said magnets in their deenergized condition, a pair of balanced springs 37-37 will act to hold levers 31 and thereby the printing drum 6 at substantially a midpoint position relative to bringing one or the other of two rows of printing characters arranged around the circumference of drum 6 to the printing line with respect to platen 3. It is intended, however, that either magnet shall remain normally energized in accordance with any previous final impulse signal transmitted thereto from the known input devices.

It will be apparent from the above, therefore, that upon simultaneously deenergizing either one of said magnets while energizing the other in accordance with a selected impulse signal, armature 34 will move either upwardly or downwardly until stopped by the particular magnet that becomes energized. Thus the lever 31 is rocked either clockwise or counterclockwise about point 32 in accordance with such impulse signals, and will raise or lower shaft with printing head 6 to selectively bring either row of printing characters thereon into printing alignment with the work support platen 3.

It will be noted that in such operations, potential energy provided in one of the opposed springs 37-37 will decrease while that of the other spring will increase, with the result that lever 31 with armature 34 is caused to be spring biased for either direction of its movement.

This arrangement of spring balancing and with providing caps 38 of suitable anti-magnetic material, such as tetrafluoroethylene, commonly known as Teflon, upon the core of each magnet serves to provide for a more rapid response of the above devices to any said input impulse signals thereto.

A selection of any desired character to be printed is effected through selective forward or reverse operations of stepping motor 28 to adjust drum 6 from any last previous character selection position to any other character position according to the particular input signals received thereto from the master control devices.

The novel means for effecting a fore and aft printing stroke movement of the printing character drum 6 will now be described.

Rotatably mounted upon a pair of spaced studs 40, 41 fast to the frame 20 of the shiftable carriage C are pulley wheels 42, 43, respectively. Guided between the trunnion arms 22 supporting the pivoted rock frame 24, upon which is mounted the printing drum 6, is a slide block 44 having a pair of spaced shoulders 45, 46 extending rearwardly of cooperating spaced arms 47, 48 depending downwardly from said rock frame 24. An elongated notch 49 in block 44 permits said block to straddle the motor shaft 27, while a rod 50, mounted between the shoulders 45, 46 has one end of a spring 51 secured thereto. The other end of spring 51 is secured to a stud 52 fast within frame 20 and serves to bias block 44 rearwardly. A pair of springs 61, each at one end, being connected to the related arm 47, 48, respectively, and at their other end to a rod 62, held in a suitable notch in the rearward face of shoulders 45, 46, serves to yieldably bias said arms against the forward surface of said shoulders. The forward end of block 44 is bifurcated to form upper and lower bearing support for a shaft 53 upon which is mounted for rotation between said supports a pulley wheel 54.

With reference to FIGS. 1-lA, a flexible steel tape 55 is secured by stud 56 to the fixed bracket 12 of the machine and extends leftwardly, around the forward surface of pulley wheel 43, thereafter rearwardly around the pulley 54, forwardly around pulley 42 and again leftwardly to pass around a stationary pulley 57 and thence is secured at its opposite end to the distal end of a resilient reed 58 (FIGS. 2 and 3), having the opposite end thereof fast to the base plate 59'. Said reed comprises the armature member for a pair of parallel electromagnets 60 fast to the base plate 59, and is designed to effect a printing operation of the drum in the following manner.

Assuming power has been turned on in the machine with the result that magnets 60 are thus energized, reed 58 is now deflected and held by said magnets so that tape 55 will be in a released condition. This permits spring 4 51 to hold slide block 44 with pulley 54 in a rearward position, thereby taking up any slack which would be imparted to tape 55 by said deflection of reed 58. At this time, springs 61 will cause frame 24 with printing head 6 to be held in a counterclockwise position.

Magnets 60 may thereafter be deenergized and reenergized according to an established impulse repetition rate as transmitted thereto from any well-known control devices. So that any residual magnetism in magnets 60 will not delay a release of the reed 58, the side of said reed towards magnets 60 is covered with a suitable antimagnetic substance, such as for instance, tetrafluoroethylene and known commonly under the name Teflon. Upon a deenergizing of magnets 60, reed 58 is released and will impart a leftward movement (FIG. 1) to the tape 55. The opposite end of tape 55 being held, as earlier described, it will be obvious that pulley 54 will be moved forwardly, being leftwardly as shown in FIGS. 5 and 6, and will move slide block 44 therewith to impart thereby a rapid clockwise rotation to the frame 24 and printing head 6. During such operation, reed 58 reaches its maximum velocity and will then decelerate in characteristic manner. However, tape 55 will only pull slide block 44 partly forward, whereafter acceleration imparted thereby to frame 24 and printing head 6 will cause the printing head to continue onward and strike the usual type ribbon 63 for printing upon any record form as interposed between said ribbon and the support platen 3. During this latter portion of the printing stroke, it is noted that the deceleration of reed 58- slows motion of slide block 44 and the printing head is permitted to strike freely, so that no printing impact is transmitted back to the tape, thereby avoiding damage to the tape.

On the return stroke of the oscillation of reed 58, tape '55 is caused to be relaxed, permitting spring 51 to return slide block 44 rearwardly, while springs 61, as aided by rebound of the parts and by increased energy stored therein during the printing stroke, restores frame 24 and printing head 6 counterclockwise to normal position.

From the above therefore, it will be noted that because reed 58 acts like a leaf spring, it tends to resonate but is restricted to one cycle, that is, it leaves the magnets 60 as said magents are deenergized and pulls tape 55 on a forward stroke, or away from the magnets. On the return stroke of the reed 58, in completing the cycle, said reed is recaptured by magnets 60 when energized, as hereinafter described, by a control circuit applied to said magnets at a given time before the reed has fully returned and which builds up the magnetic field sufficiently to pull reed 58 a remaining short distance to normal, whereby the associated parts operated by tape 55 also return to normal, with a minimum of chatter or rebound.

To further understand certain operations and advantages of applicants novel devices, reference is made to the graphic illustrations shown in FIGS. 9, 9A and 10, which will now be described.

FIG. 9 illustrates the force applied by magnets 60 for deflecting power reed 58 incident to an initial potential energy storing stroke for said reed and as related to the required force of said magnets for any subsequent deflections of the reed.

Assuming at the start that all power is off, the reed 58 would then have no deflection, as illustrated at ZERO DEFL. on the x coordinate. An initial momentary high current force of a magnitude to saturate magnets 60 for deflecting reed 58 sufliciently to close the initial gap G may be induced incident to the turning on of power or in any other suitable manner and is illustrated by the high current force line, which it will be noted is throughout always above or greater to the force line R representing the deflection requirement of reed 58. Immediately subsequent to the high current maximum force, indicated at F on the y axis, it is intended that maximum magnetic force on the magnets shall drop to a point P on the chart.

This reduced force, however, will maintain said magnets energized suflicient to hold reed 58 at its maximum deflection point +D. Thereafter, at any time, magnet 60 is caused to be deenergized reed 58 being released and by virtue of its inbuilt potential energy will move at its natural resonance to the point D and immediately back to a point +D as indicated by broken lines on the chart. At said point suitable well-known circuit control means, which include a one shot multivibrator OSM (FIG. 9A) will function to reenergize magnets 60, whereupon said magnets complete the final gap closing movement of reed 58 to the magnet, as represented by the solid line from point +D to point +D on the chart. Now from the above and by observation of the chart, it will be noticed that the low current magnetic force curve will intercept the force line R, requirement for the reed at substantially the line +D and will fall below the designed reed force R along a substantial portion of said line R. Thus the kinetic energy of the moving reed is being utilized during this time portion, and a reduced power is therefore possible for magnets 60 to return reed 58 the remaining short gap represented by line +D' to +D and restore full potential energy to said reed. Also, more latitude is permissible in the timing for reenergizing of said magnet.

FIG. is a sinusoidal wave chart, relating the velocity curve of the reed 58 with a time displacement curve thereof and indicating the manner in which the reed becomes self-cushioning in the printing oscillation thereof and how the shock, earlier described, is minimized in the operations of the reed. Also, FIG. 10 with FIG. 9A illustrates how the reed power means functions to operate the printing devices in a given time sequence with any input repetition rate from the master control devices.

Assuming that the magnet 60 is now energized, reed 58 will be held by said magnets at its maximum potential nergy shown at +D on the y coordinate. The reed being stationary is so illustrated at zero velocity (ZERO VEL.) on the conjunction of coordinates xy. Upon release of reed 58 following a deenergizing of magnet 60, the reed advances to zero deflection point A on the reed displacement curve. At this time, the reed has attained maximum velocity as indicated on the velocity curve. Reed 58 now reverses its force as it moves beyond point A to point D during which the velocity curve will again go to zero. However it will be recalled that the printing head 6 will continue in its forward printing stroke movement to effect a printing during this period movement of reed 58. Returning now from point -D the reed curve recrosses the x axis at return maximum velocity and its force again is reversed in going to the point +D' at which point velocity will again be zero and all kinetic energy has now been translated to potential energy in reed 58.

It is recalled that at +D' reed 58 is not as yet fully returned to the magnets 60, indicated at point +D on the graphs. At this time, as earlier set forth, suitable one shot multivibrator time delay circuit means OSM (FIG. 9A) well-known to the art, will cause a reenergizing of magnets 60 to complete the deflection of reed 58 from point +D' to point +D. It will be noted from the velocity curve that during this short movement and time period the velocity of reed 58 produced by magnets 60 is so low that very little impact occurs as reed 59 strikes magnets 60 and thereby avoids noise and shock, with a possible breaking occurring to the tape 55.

Since any buildup time required in energizing magnets 60 are known, it of course, is possible to time its energizing action slightly early to the point +D on the chart.

From the above description, it will be apparent that during any repetitious incoming signals spaced at a predetermined time interval, as from any suitable master control machine, magnets 60 are caused to be deenergized each time for releasing a power reed 58 to effect by said reed successive printing operations and that said magnets are timed by known circuit control devices to be reenergized in a timed sequence with such input signals so as to complete the restoring of potential energy again within reed 58 in corresponding time for each subsequent release thereof.

Suitable well-known feed back circuits, not herein deemed necessary to set forth, may be included where required to control timing starts for any input signal to the printer from the master control means.

While there has been shown a preferred embodiment of the invention, it will be understood that various changes may be made in the form, detail, arrangement and proportions of the parts without departing from the spirit and scope of the invention. Accordingly, it is intended that the foregoing disclosure be illustrative only and not limitative of the following claims.

I claim:

1. A printing mechanism comprising a print head having first and second] rows of indicia thereon alternatively alignable with a printing position;

a shaft mounted for sliding, rotational and tilting motion on which said head is mounted;

an arm mounted about an axis, said arm having first and second sides;

means coupling said arm to said shaft for permitting relative tilting, rotational and sliding motion between said arm and said shaft;

said arm engaging said shaft to shift said shaft and thereby said print head to a first position wherein a first set of indicia is aligned with the printing position and a second position wherein the second set of indicia is aligned with the printing position;

a first electromagnetic means positioned adjacent to said arm and adapted to move said arm about said axis;

a second electromagnetic means positioned adjacent to said second side of said arm and adapted to move said arm about said axis;

spring means biasing said arm to midpoint position between said first and second electromagnetic means and adapted to have potential energy stored therein upon movement of said arm;

said spring means coacting with said first means to release potential energy stored in the spring to cause movement of said arm about said axis to thereby cause said print head to move between said first position and said second position.

2. The mechanism of claim 1 wherein second spring means is provided, which spring means is connected to said arm adjacent said second side thereof, and wherein said second spring means is adapted to have potential energy stored therein upon movement of said arm, and wherein said second spring means coacts with said second electromagnetic means to release the potential energy stored in the spring to cause movement of said arm about said axis and thereby cause the print head to move between said second position and said first position.

3. The mechanism of claim 2 wherein said arm has a first end and a second end, said first end being proximal to said printing head and said second end being distal to said printing head; and

wherein said axis is positioned between said first and second ends and between said first and second sides.

4. The mechanism of claim 3 wherein said first electromagnetic means is positioned adjacent said first side of said arm and between said axis and first end, and wherein said second electromagnetic means is positioned adjacent said second side and between said axis and said first end.

5. The mechanism of claim 4 wherein said first and second spring means are connected to said arm between said axis and said second end.

6. The mechanism of claim 5 wherein said first and second electromagnetic means comprise electromagnets which are adapted to be energized and deenergized and wherein said first spring means and said second biasing means comprise tension springs.

7. The mechanism of claim 6 wherein said arm is horizontally disposed and said electromagnets are disposed substantially perpendicular to said arm and said springs are positioned substantially perpendicular to said arm.

8. The mechanism of claim 7 wherein said electromagnetic means comprise solenoids.

9. The mechanism of claim 8 wherein said print head comprises a circular disc, and

wherein said first and second set of indicia comprises parallel bands of print symbols.

10. The mechanism of claim 9 wherein:

a shoulder is provided on said shaft, which shoulder is engaged by said arm to interconnect the arm and the print head.

11. The mechanism of claim 6, said shoulder being a flat projecting member having a first and second surface and being positioned in a plane perpendicular to said shaft, said arm having a first and second spring finger projecting therefrom, said shoulder being engaged between said spring fingers so that said first surface is engaged by the first spring finger and said second surface is engaged by said second spring finger, whereby said shoulder and said shaft are adapted to tiltably move in an arc, to slideably move vertically and to move rotationally while being engaged by said fingers.

References Cited UNITED STATES PATENTS 1,736,683 11/1929 Wakeland 335-181 2,633,488 3/1953 Brion 335274 XR 485,761 11/1892 Heiss 197-12 1,083,076 12/1913 Fischer 197-12 1,355,089 10/1920 Clark -2 197-12 1,936,656 11/1933 Bell 178-34 2,029,957 2/1936 Trachtenberg 19712 3,286,806 11/1966 Schoenfelder 197-55 XR 3,291,041 12/1966 Burchfield et a]. 19755 XR EDGAR S. BURR, Primary Examiner US. Cl. X.R. 197--55

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