US2306223A - Automatic tube bending machine - Google Patents

Description

Deg. 22, 1942. A. 1.. PARKER ET AL AUTOMATIC TUBE BENDING MACHINE Filed March 51, 1.941 llv Sheets-Sheej 1 firm/ru ers A. L. PARKER ET AL AUTOMATIC TUBE BENDING MACHINE I Dec. 22, 1942.

Filed Marh 31, 1941 11 Sheets-Sheet 2 lllllllllllrll I I 1 l l l l I I lll 'lllllliv A. L. PARKER ETAL 2,306,223 AUTOMATIC TUBE BENDING MACHINE Dec. 22, 1942.

Filed March 31, 1941 ll Sheets-Sheet 3 W Gail},

H I I 3 4 R kw Dec. 22, 1942. A. L PARKER ETAL I AUTOMATIC TUBE BENDING MACH INE Filed March 31, 1941 11 Sheets-Sheet 4 Dec. 22, 1942. A.VL.' PARKER AL I 2,306,223

AUTOMATIC TUBE BENDING MACHINE Filed March 31, 1941 v 11 Sheets-Sheet s Dec. 22, 1942. A. L. PARKER ETAL AUTOMATIC TUBE BENDING MACHINE I Filed March 51, 1941 11 Sheets-Sheet 6 I Err-004 8)! Dec. 22, 1942.

A. L. PARKER ErAL AUTOMATIC TUBE BENDING MACHINE 11 Sheets-Sheet '7 Filed March 31". 1941 Illililllllllllllllllllliiiiilil" l-mllllllllll A. L. PARKER ET AL v AUTOMATIEJ TUBE BENDING magma llSheets-Sheet 8 Filed March 31,1941

Ina 544 413 FITOfiWsa a umur Dec. 22,- 1942.

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Dec. 22,1942. A. L. PARKER. ET AL, 2,306,223 I.

' AUTOMATIC .TUBE BENDING MACHINE Filed March 31,1941 11 Sheets-Sheet 10 J J Irma-#5063: a g MGM M ra} Fri-094016 Dec. 22, 1942. w 'A. L. PARKER ETAL 2 3 I 7 AUTOMATIC TUBE BENDING MACHINE Filed March 51, 1941 v 11 Sheets-Sheet 11,

Patented Dec. 22, 1942 U NlTED STATES AUTOMATIC TUBE BENDING 'MAGHINE Arthur L. Parker and Henry E. Hull, Cleveland, 'Ohio; said Hull assignor to said Parker Application March 31, 1941, Serial -No.-386,206

16 Claims.

The invention relates to certain new and useful improvements in tube bending machinery, particularly in tube bending machines of the character illustrated in thecopending ap lication for U. S. Letters PatentSerial No. 314,042,1"1led-0n L) bending and return movements to said rotor, a .2..-

fluid actuated clamp means for clamping tubes to the rotor, a fluid actuated clamp means for clamping a slidable Vise block in opposition to the tube androtor, a tube shape retaining mandrel, a motor for projecting the mandrel to and retracting it from its effective position, rotor movement braking means, and electrical control means including a bending cycle initiating button which when pressed causes the clamping devices to clamp the tube and-set the vise block, to automatically condition the rotor motor control circuit for the desired right or left bend, to start the rotor motor, and means to break the rotor motor control circuit and apply the brake means when the degree of bend intended has been completed, and also to effect retraction of the mandrel and thereafter release said clamping devices, thereby to complete a bending cycle. The control equipments also include a return button which when pressed initiates an automatically completed return cycle including replacement of the mandrel to its effective position, starting of the rotor motor in reverse or return direction and the breaking of the control circuits and the application of the rotor movement braking means upon completion of the mandrel positioning and the return to normal of said rotor.

Another object of the invention is to provide a machine. of the character stated including a single solenoid operated valve which coordinates the electrical control circuits with both fluid actuated clamping means.

Another object of the invention is to provide a machine of the character stated including a novel circuit controlling switch arrangement as sociated with the clamping equipment so as to prevent initiation of a bending operation prior to proper clamping of the tube.

Another object of the invention is to provide a machine of. the .characterstated including a circuit controlling switch arrangement associated with the mandrel positioning means and the bending-rotor motor-circuitsoas to prevent initiation of a bending" operation -while the-mandrel is retracted;

Another object of the invention is toprovide a machine of the-character stated including an ad justable bending rotor' motor circuit controlling switch equipment effective to-discontinue' abending operation when the desired degreeof bending of the tube has been completed.

Another object of the invention is to provide a machine of the character stated includinganovel bending rotor motor circuit controlling switch effective by engagement-or non-engagement--by the vis block carrying armto condition the circuitfor'driving saidmotor'one way or another according to the intended direction-of 1 bend.

Another object of the invention is toprovide a machine of the character statedincluding-a manual-ly operable button effective when pressed and held to directly and manuallycontrol the clamp means operating valve independent of the automatic cycles. 1

Another object ofthe invention is to provide a machine of'the character stated including manually operable buttons for directly controlling mandrel projection and retraction independent of the automatic cycles, and also-a button which may beactuated to stop the machine at any time.

With the above and -otherobjects in view that will hereinafter appear, the nature of the invention will be more fully understood by following the detailed description, the: appended claims, and the several views illustrated in the accompanying drawings.

In the drawings:

Figure-lie a plan view illustrating the invention, the parts being illustrated imposition after completion of a bending cycle and before the start of the return'cycle.

Figure 2 "is anenlarged fragmentary plan view of the bending-head structure, the parts being illustrated'in full lines as having completed 90 of a bend, the completion of a bend such as is illustrated in Fi 1 being indicated in dotted lines.

Figure 3 is an enlarged fragmentary plan View illustrating the cooperative relation of the mandrel and .the vise slide block, parts being broken awayand. in section. I

Figure. v4 isaivertical cross-section taken substantiallyon the linell on Fig. -2.

Fig. 5 isa: fragmentary vertical cross-section taken on the 1ine 5--5 on "Figil,

Figure 6 is a vertical longitudinal section taken substantially on the line 6-6 on Fig. 2.

Figure 7 is a horizontal section taken through the plane of the heart cam in the bending head, parts being broken away and illustrated in plan view.

Figure 8 is an enlarged fragmentary longitudinal ectional view taken on the line 8-8 on Fig. 7.

Figure 9 is a detail vertical cross-section taken on the line 9-9 on Fig. 8.

Figure 10 is an enlarged fragmentary vertical cross-section taken on the line llll0 on Fig. 1.

Figure 11 is a vertical longitudinal sectional view taken on the line Illl on Fig. 10, parts being broken away and shown in side elevation.

Figure 12 is an inverted plan view illustrating the positioning of the bending head driving motor, the clamp controlling valve, the bending rotor driving connections, and the braking equipment.

Figure 13 is a side elevation of the parts illustrated in Fig. 12, parts being broken away and in section.

Figure 14 is a detail end elevation of the braking equipment, the association of. the controlling solenoid therewith being illustrated somewhat diagrammatically.

Figure 15 is a detail vertical cross-section taken on the line l5--l5 on Fig. 14.

Figure 16 is a diagrammatic sectional view illustrating the clamp controlling valve and its connection with the clamp actuating cylinders.

Figure 17 is a diagrammatic view illustrating the circuit connections with the various machine parts.

In the example of embodiment of the invention herein disclosed, there is included a long rectangular table or supporting structure comprising a top plate 5 which is supplemented at one end by a bending head supporting plate 6, both said plates being secured upon a frame structure including sides 1 and corner standards or supporting legs 8.

An end plate 9 is supported across the front end of the machine and carries a control panel H) equipped with six control buttons designated a clampbutton II, an extractor button l2, a mandrel button I 3, a stop button l4, a bend button l5, and a return button [6, all arranged in a line across the panel in the manner best illustrated in Figs. 1, 7 and 13 of the drawings.

. .These buttons comprise the manual controls associated with the electrical circuits and control devices which are mounted in part in the controller box I! supported beneath the panel ID in the position best illustrated in Fig. 13.

A bending head housing I8 is fiange-secured, as at l9, upon the support plate 6 and includes a front super-structure or upward extension 20 terminating rearwardly in transversely aligned abutment walls 2|.

Rearwardly of the upward extension 20, the housing I8 is equipped with a vertically disposed shaft bearing 22 for rotatably supporting a rotor shaft 23 which has a'large spur gear 24 affixed to its lower end, said gear being recessed at its under surface to accommodate the positioning of a heart cam 25 which is secured to-the gear as at 26.

The heart cam 25 engages fore and aft with and between rollers 21 secured to and extending upwardly from a frame 28 slidably mounted in guides 29 secured upon the support plate 6, see Figs. 4, 6 and '7 of the drawings. The purpose of ,the slidably mounted frame 28 will become apparent as the descriptionprogresses,

A bending rotor 30 is affixed to the upper end of the shaft 23 and carries a radius block mounting pin 3| which is disposed coaxially with the shaft 23, and a radius block driving pin 32 which projects upwardly from the rotor in eccentric relation to the axis thereof. The mounting and driving pins 3| and 32 are receivable in bearings 33 formed on selective radius blocks 34 each of which is peripherally grooved to properly engage a, tube to 'be bent and includes a tangential extension 35 which is similarly grooved and against which a tube to be bent is clamped in a manner later to be described. It will be obvious that by clamping a tube end to the tangential extension of a radius block and imparting rotation to said block, a bend will be formed in said tube in a manner well known in this art.

For imparting the desired rotation to the bendingrotor 30, there is provided a countershaft 36 which is rotatably supported, as at 31, in the head or housing and is equipped with a driving pinion 38 enmeshed in driving relation with the spur gear 24. The shaft 36 also carries a large driven gear 39 to which rotation is imparted by a pinion 40 mounted on a vertical drive shaft 4| rotatably supported, as at 42, and extended downwardly through the support plate 6 into a drive gear housing 43 secured beneath said plate in the manner best illustrated in Figs. 6, '7, 12 and 13 of the drawings.

Within the housing 43, the shaft 4| carries a worm wheel 44 to which rotation is imparted by -a worm gear 45 secured upon a driver shaft 46 equipped with a pulley 41 and driven by a transmission belt 48 from any suitable variable speed, spring-pressed drive pulley 49. The driver pulley 49 is mounted on the drive shaft of the bending rotor drive motor 50, said motor being suspended from a slide 5i slidable in guides 52 supported on the table. The guides are disposed in angular relation to the plane in which the driver pulley 49 rotates, and by adjusting the position of the motor by movement of the slide, the motor can be moved to vary the spaced relation thereof with the driver pulley 41 and also laterally with respect to the transmission belt 48 so as to cause the spring-pressed halves of the pulley 49 to spread apart or come together, according to the direction in which the motor is moved, thereby to vary the speed of rotation imparted to the pulley 41.

In order to provide for the desired adjustment of the motor position, an adjuster screw 53 is provided which threads through a nut 54 fixed to the motor slide, said screw being turned through the medium of a hand wheel and suitable driving connections generally designated 55. Movement of the motor slide may be suitably limited by stops 56, see Figs. 12 and 13 of the drawings.

A vise slide block arm 5'! projects radially from the rotor center and includes a mounting hub 58 which surrounds the rotor shaft 23 below the rotor in the manner illustrated in Figs. 2, 4 and 6 of the drawings. The spaced parallel bars comprising the main body of the arm 5'! may be supported at their free ends against downwardly girecied thrusts upon an adjustable prop 59, see

The parallel bars comprising the arm 51 are apertured, as at 60, to receive a removable screw 6| which passes through the apertures and through an opening in a screw bearing 62 for the purpose of adjustably anchoring said bearing upon the arm. The screw also passes through a spacer member 63 disposed at one'side'of one of the arm bars in the manner best illustrated in Fig. of the drawings. The bearing member 62 is equipped with a threaded bore for receiving an adjuster screw 843 which is rotatably secured, as at 35, to a bearing standard 88 slidably supported upon the arm 5'? and equipped at its base with a longitudinal slot 81 for receiving an anchoring screw 88 which passes through selected apertures 80 in said arm. Thus mounted, the standard is capable of limited adjustment back and forth along the arm El by manipulation of the screw 50. v

A vise block 69 is slidably mounted, as at I0, on the arm 5? and is equipped with slideways H for a slide 72 having a shelf portion F3 on which to support a selected vise slide block I8. The selected slide blocks I i are square in cross-section and are equipped at each face with a groove of a distinct size so as to adapt each said block for proper clamping engagement with tubes of a multiple of sizes. The selected slide'block- I4 may be removably secured to the supporting slide 712, as at I5, and it will be observed by reference to Figs. 2, 3 and 4 of the drawings that the slide engages anti-friction rollers it carried by the block 88, thereby to permit the slide and the slide block M to slide along in contact with the engaged tube while it is being bent and without engaging the same in abrasive contact.

Toggle links T? are anchored respectively to the vise block 59 and the standard 66 and are pivotally connected together and to a piston rod l8 projecting from the lower endoi a fluid pressure cylinder '59 which is swingably supported, as at 88, at the top of said standard. Fluid pressure lines 8! connect with the cylinder above and below the piston 82 which is reciprocable therein and connect at their other ends with a single control valve 83 having selective pressure flow ports 84-, a supply port 85, and an exhaust port 86. The valve rotor 87 by which port communi cation selection is made is crank and link connected, as at 88, with the core of an actuating solenoid 89. It is to be understood that the valve rotor is shifted to a position for directing fluid pressure into the upper end of the cylinder I9 and causing a straightening out of the toggle; links Ill each time the solenoid 89 is energized, and when this solenoid is ale-energized, the valve rotor is spring returned to the toggle collapsing position, see Figs. 16 and 17.

The standard 56 carries a circuit controlling switch G connected by an actuator chain 90 with the toggle links as indicated in Figs. 4 and 1? so that the switch is closed whenever the toggle links are extended as in Fig. 4. The purpose of this switch will become apparent as the description progresses.

A clamp arm M is pivoted, as at 82, to swing about the driver pin 32, and a bearing standard 83 is slide guided, as at 84, on said arm. The standard includes a solid body portion 85 to which an adjustment screw 85 is rotatably anchored as at $1. The screw passes through a threaded bore in a block 88 secured upon the arm. A clamp block '92] is slidably mounted, as at 400, on the arm 81 and carries a support shelf Hill on which a clamping block M32 is secured, as

at l83. Like the vise slide block I 3, the clamp block IE2 is square in cros's section and has each face thereof equipped with a tube engaging groove of distinct size.

' Toggle links E04 are anchored respectively to the ciamp'bwcms amine-standard as and are connected together and to the piston rod I05 which projects downward from a fluid pressure cylinderl06 which ispivotally supported, as at I0I, at the top of the standard I03. Like the pressure cylinder I9 previously referred to, the cylinder I08 is connected at top and bottom, above and below the reciprocable piston I08, with pressure lines'I09 which connect with the previously mentioned lines- 8| leading to the ports ti t of the single control valve 83, see Figs. 5 and 16.

A- mandrel H0 is provided and includes a shaped tip II I which engages in the tube II2 being bent directly opposite the bending rotor, or at the bend center, thereby to support the tube internally as it is being bent and prevent flattening out thereof at the point of bend. The mandrel 5 i8 is mounted at the free end of a mandrel rod H3 which is removably coupled, as at II4, to a vibratory mandrel positioning rod H5, see Figs. 1, 3 and 11 of the drawings. The vibratory rod I l5 passes through a housing H6 which is laterally-adju'stably secured, as at 1, upon a transversebeam I I8 mounted upon the table top at the end of the machine remote from the bending head. The housing is equipped with a pointer H9 associated with a scale I20 mounted on the beam H8, and by provision of this equipment it is possible to accurately gage and thereby facilitate positioning of the housing H5 and the mandrel anchoring and adjusting equipment supported thereby.

The longitudinally movable or vibratory rod H5 is spline-connected with the housing H6, as at I2l, so as to be held against rotation, and this rod is externally threaded, asat I22, for engagement in the internally threaded bore provided in the adjusting sleeve I23. The sleeve I23 is rotatably mounted in the housing but is held against longitudinal movement therein and is equipped with a worm wheel I24 to which rotation is imparted by a worm gear I25 secured upon the shaft of the mandrel positioning motor I26 secured, as at I21, to the housing. It will be obvious that when the motor I26 is operating, rotation will be imparted to the adjuster sleeve I23 and longitudinal movement will be imparted to the vibratory rod H5 and the mandrel attached thereto, in one direction or the other according to the direction of rotation of the reversible motor I26.

Fixed actuator cams I28 are secured in spaced relation on the red I I5 and these are engageable with the rollers I29 carried on the swingable actuator arms I38 of switch structures H and K.

The switches H and K are so connected in the electrical control circuits that when the switch H is engaged by the respective cam E28 and opened, it discontinues operation of the motor I26 and retraction of the mandrel, and whenthe switch K is engaged by the respective cam I28 and opened, it discontinues operation of the motor I26 and projection or advancement of the mandrel. I

For adjustably determining the desired angle of bond to be formed in a given tube, and for stopping the mechanism when this degree of bend has been accomplished, there has been provided a stop block I'3l which is disposed in the path of movement of the slide 28 he'reinbeiorereferred to." An anchored spring I32 constant ly tends to draw the block I3I toward the slide 28 and the block is secured at the and of' an. externally threaded rod" I133 engaged in the iiiternally threaded bore of adjuster site-vent rotatable in a bearing I35 provided in the bender head housing in the manner best illustrated in Fig, 8. The sleeve I34 is equipped with a hand wheel I36 having flattened facets I31 engaged by a flat, position retaining spring I38 anchored to the machine frame. It will be obvious that by turning the hand wheel I36, the position of the stop block I3I can be altered at will.

The adjuster sleeve I34 is externally threaded, as at I39, and meshes with a worm wheel I40 mounted on a vertical shaft rotatably supported at MI in the housing and equipped with a visible dial I42 settable by adjustment of the hand wheel I36 in the manner above described for displaying the degree of bend to be attained during a given bending cycle,

The shaft 35 is equipped at its upper end with a small pinion I43 which meshes with a large gear I44 carrying a visible dial I45 which can be observed during bending operations to determine the degree of bend which has been attained at any given time during the bending cycle.

The adjuster sleeve is equipped with a cam portion I46 engageable with a roller I41 carried at the upperend of the depressible actuator I48 of a control switch A connected in the electrical control circuit and effective whenever it is opened by depression of the element I48 to discontinue the bending cycle. It is to be understood that each time the frame 28 engages and longitudinally shifts the stop block I3I to signify that the desired degree of bend has been attained, circuit breaking actuation of the switch will be accomplished by engagement of the cam portion I46 with the roller I41.

A return stop cam I49 projects from the upper surface of thegear 24 and is engageable, when the bending rotor is at the zero point, with the actuator roller I 50 of a return stop switch J. It is to be understood that the switch J is connected in the control circuits, and whenever it is engaged at the return of the bending rotor to the zero point, the circuit will be broken and the return movement'of the parts discontinued in a manner hereinafter again referred to.

A brake drum portion II is provided on the rotor drive shaft 46 and is engaged by a brakingequipment so as to definitely stop rotation of the rotor the instant the desired degree of bend in the tube has been completed during the bending cycle, and also at the instant that the parts are returned to'the zero point in the return cycle.

The braking equipment is best illustrated in Figs. 12, 14 and 15 and includes brake shoes I52 engageable at opposite sides of the brake drum portion I5I and carried by brake arms I53 and I54 which are pivotally connected as at I55. A threaded rod I56 is secured, as at I51, to the arm equipment I53 and has an abutment collar I58 threadably adjustable thereon, said collar being opposed by a block I59 slidably mounted on said rod. The rod includes an adjustable abutment head I60, and a compression spring I6I is interposed between this head and a pressure applying disk I62 which is freely slidable on the rod and engages lugs I63 projecting from the arm equipment I54. This spring is normally effective to move the arm equipments I53 and I54 toward each other so as to apply the brake shoes I52. A brake releasing head I64 is pivoted, as at I65, to the block I59, and it is also pivoted, as at I66, at a higher point, to the arm equipment I54. A lever I61 extends from the head I64 and is engageable at I68 by the retractable core I69 of a solenoid I16.

It is to be understood that when the solenoid I is energized, retraction of the core thereof lifts the lever I61 and causes the pivot pin I66 to swing'about the lower pivot I65 now rendered a fixed fulcrum by abutment with the collar I68, thereby causing the lugs I63 to compress the spring I6I, move the arm equipments I53 and I54 apart, and relieve the braking pressure of the shoe I62.

, It will be observed by reference to Figs. 2 and 17 of the drawings that one of the abutment walls 2I of the housing extension 26 carries a circuit selector switch S effective to control the making of right or left hand bends. This switch includes a spring-projected actuator plunger I1I which is engageable by the vise block arm 51 when swung to that particular side of the machine, that is, to the position opposite that illustrated in Fig. 1.

In Fig. 17 of the drawings the electrical control circuits are diagrammatically illustrated in combination with the associated parts of the machine, the association of these mechanical parts also being illustrated diagrammatically. The bender motor 56 is a 3-phase, A. C. motor, and the same is true of the mandrel positioning motor I26. The control circuits illustrated diagrammatically in Fig. 17 include the usual main power input lines X, Y and Z and the several switches which have been referred to hereinbefore, namely, the clamp switch G which permits the bending operation to start only after the tube clamping equipment has been properly set, the mandrel position controlling switches H and K, the actuation of the former of which stops movement of" the mandrel when it has been projected a proper distance, and actuation of the latter of which stops movement of the mandrel after it has been retracted a proper distance, the switch S which selects the circuits for a bend in a particular direction according to the positioning of the clamp arm 51, the switch A which serves to terminate the bending operation after the intended degree of bend has been completed, and the switch J which terminates return movement of the rotor at the zero point. All of these switches have been referred to hereinbefore and are diagrammatically indicated in Fig. 17.

All of the manually actuated control buttons II through I6 and the connections thereof in the control circuits are indicated in Fig. 17, and it will be observed by reference to this figure that the electrical control equipments include a bending motor controller including alternately closable relays L and R, a mandrel positioning motor controller including alternately closable relays M and E, a bending controlling relay B, and a return controlling relay D, all shown at the lower left hand corner of Fig. 17.

The radius block 34 is removably and reversibly mounted on the pins 3I and 32 so that the tangential clamping face 35 thereof can be disposed to one side or the other for making right or left hand bends. For a like purpose, th arm 9| can be swung to one side or the other about,

parallel arms comprising the arm structure 51, whereas when this arm structure is swung to the opposite side of the rotor said parts 62 and 61 will be removed and mounted on the other parallel arm comprising the arm structure 51. It should also be obvious that when the arm structure is swung to the opposite side of the rotor, as viewed in Figure 1, it will engage the switch button Ill and thus condition the electrical control circuit so that when the bending cycle is initiated the rotor will rotate in a clockwise direction, as viewed in Figure 1, and form a bend in a direction opposite that indicated in Figure 1. The adjustable mounting of the mandrel shown in detail in Figures 1, and 11 permits placement of the mandrel to one side or the other of a line passing through the center of the rotor accordingly as the clamping face 35 is placed to one side or the other, and, as previously stated, the rotor driving motor 50 is reversible.

It should be obvious, therefore, that either right or left hand bends can be made in tubes placed in this machine. It should be noted also that the scales I29, IZ and M5 are marked both directions from zero so as to facilitate placement of the parts and the observation and gaging of bending perations.

The bending cycle Assuming a tube to be properly placed in the machine, the automatic bending cycle is started by pressing the bend button 15. Thi completes a circuit from power line X through the undepressed stop button l4,back throughthe depre sed bend button l5, through normally closed contact D through bend relay coil B, through the mandrel position controlling switch H to line Z. This energizes coil B which closes the normally open contacts B 13 and B and opens the normally closed contact B cuit after the bend button 55 is released and until the end of the bending cycle. Contact B allows current to flow through the solenoid 89, thus openin the clamp valve 83 and allowing fluid pressure to force the cylinder pistons downwardly, straighten out the two sets of toggle links, and apply the clamping devices. Contact B switch G, and the adjustable switch A .(contact A operate in series to allow current to pass through the bend circuit selecting switch S for energizing either left hand or right hand bend starting coils of the relays L or R depending upon the side of the machine upon which the slide block arm 5'! is located. The coil of the relay L will cause the bender motor 59 to rotate in the proper direction for making a left hand bend in the tube, or the coil of the relay R will cause reverse rotation for a right hand bend. Near the completion of the bend, contact A of the switch A is forced to close, causing current from the line X to flow through the coil of the mandrel extracting relay E, and through the mandrel position controlling switch H to the line Z. The coil of the relay E being thus energized allows the contacts of this relay to close and start the mandrel positioning motor I26 for retracting the mandrel. An instant later, contact A of the switch A opens, deenergizing the particular motor control coil of the relay L or R which happens to be operating at that particular time, thus shutting off the current in the leads to the bender motor 58. The breaking of the power circuit to the motor 50 also de-energizes the brake controlling solenoid I79 and, as previously described, whenever this solenoid is de- Contact B maintains the cirenergized the braking equipment is applied to instantly stop rotation of the rotor.

The mandrel positioning motor I26 continues to run in the mandrel retracting direction until the cam on the mandrel shifting rod engages and opens the switch H. This stops the motor I26 and de-energizes the coil of the bend relay B. The contacts controlled by the relay B thus being opened, the clamp valve solenoid 89 is deenergized and this valve is spring shifted so as to effect an unclamping of the tube clamping equipments, thereby completing the bending cycle.

During the bend cycle the normally closed contact l3 is held open by the coil of the relay B to prevent the possibility of energizing the coil of the return relay D.

The return cycle After removing the bent tube, the return cycle is started by pressing the return button 6. This energizes the coil of the return relay D and effects a closing of the normally open contacts D and D and open the normally closed contact Contact I) maintains the circuit after the return button It is released until the end of the return cycle. Contact D energizes the coil of the mandrel advancing relay M which causes the mandrel positioning motor I26 to rotate in the proper direction for advancing the mandrel to the bending position hereinbefore described. Simultaneously, the'coil of the selected relay L or R is energized through the selector switch S previously referred to for initiating return movement of the rotor in the proper direction. This starts the bender motor in a direction the reverse of that which eiiected the bending operation, and when the rotor has returned to the zero position, the switch J is opened, thus dropping out the relay D and the control circuit then efiective in operating the bender motor 59. The mandrel positioning motor 126 is stopped at the correct position by the mandrel advance limiting switch K, the rotor motion braking equipment is applied, and the machine parts are now restored to the starting position.

The manually operable clamp button II, the extractor button I2, and the mandrel button I3 are provided principally for testing purposes during set-ups. The clamp button II energizes the clamp valve solenoid directly, but when this button is utilized the clamping equipments are applied only while the button is held down. The extractor button 92 by-passes the contact A of the switch A for starting the mandrel positioning motor I26 in the mandrel retracting direction. The mandrel button I 3 can be utilized to manually advance the mandrel to the bend starting position. The stop button M can be utilized to stop the machine at any time.

It is of course to be understood that the details of structure and arrangement of parts may be variously changed and modified without departing from the spirit and scope of the invention.

manually closing said circuit to initiate a bending cycle operation of said motor, means for manually closing said circuit to initiate a return cycle operation of said motor, adjustable means for automatically terminating the bending cycle when a predetermined degree of bend has been attained, and means for automatically terminating each return cycle with the rotor positioned at the zero point.

v '2. In a machine of the character described, a bending rotor, a single reversible electric motor for impartingrotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, means including electrical control devices for initiating a bending cycle op-' eration of said motor, means for automatically terminating the bending cycle, and means under control of said control devices for actuating said tube and vise block clamping means to engage the tube prior to commencement of said cycle.

3. In a machine of the-character described, a bending rotor, a single reversible electric motor for imparting rotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, means including electrical control devices for initiating a bending cycle operation of said motor, means for automatically terminating the bending cycle, and electrically controlled fluid pressure actuated means for actuating the tube and vise block clamping means to engage the tube necessarily prior to commencement of said cycle.

4. In a machine of the character described, a bending rotor, a single reversible electric motor for imparting rotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, means including a control circuit and electrical control devices for initiating a bending cycle operation of said motor, means for automatically terminating the bending cycle, and electrically controlled fluid pressure actuated means for actuating the tube and vise block clamping means to engage the tube prior to commencement of said cycle, said last named means comprising a normally open switch connected in the control circuit and closable as an incident to the effective actuation of said tube and vise block clamping means.

' 5. In a machine of the character described, a bending rotor, a single reversible electric motor for imparting rotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, means including a control circuit and electrical control devices for initiating a bending cycle operation of said motor, means for automatically terminating the bending cycle, a fluid pressure actuated means for operating each said clamping means, and a single electrically operable valve for controlling the operation of both fluid pressure actuated means and so connected in the control circuit as to be effective for setting the clamping means necessarily prior releasing the clamping means following completion of said bending cycle.

6. In a machine of the character described, a bending rotor, a motor for imparting rotation to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, a mandrel engageable in a tube being bent at the point of bending to support the tube against flattening, means for manually initiating and automatically terminating a bending cycle operation of said motor, means for projecting the mandrel to the point of bending prior to commencement of each bending cycle and for retracting the mandrel in the tube after completion of the intended degree of bending of said tube, and control means assuring placement of the mandrel at said point of bending before a bending cycle can be initiated.

7. In a machine of the character described, a bending rotor, a motor for imparting rotation to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, a mandrel engageable in a tube being bent at the point of bending to support the tube to commencement of the bending cycle and for against flattening, means for manually initiating and automatically terminating a bending cycle operation of said motor, means for projecting the mandrel to the point of bending prior to commencement of each bending cycle and for retracting the mandrel in the tube after completion of the intended degree of bending of said tube, and means preventing initiation of the bending cycle while the mandrel is in retracted position.

8. In a machine of the character described, a bending rotor, a motor for imparting rotation to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, a mandrel engageable in a tube being bent at the point of bending to support the tube against flattening, means for manually initiating and automatically terminating a bending cycle operation of said motor, means for projecting the mandrel to the point of bending prior to commencement of each bending cycle and for retracting the mandrel in the tube after completion of the intended degree of bending of said tube, said last named means including an adjuster rod to which said mandrel is connected, a captive sleeve threadably engaged with the rod, a reversible electric motor connected in driving relation with said sleeve, cam elements on said rod, and cut-out switches actuated by said cam elements for automatically stopping said reversible motor at the fully projected or fully retracted positions of said rod.

'9. In a machine of the character described, a bending rotor, means for imparting rotation to the rotor, a radius block rotatable with the rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, a mandrel engageable in a tube being bent at the point of bending to support the tube against flattening, power operating means for retracting the mandrel in the tube after completion of the intended degree of bending of said tube, and means controllin operation of said bending rotor rotation imparting means so that a bending operation cannot be initiated when the mandrel is retracted from its effective position at said point of bending.

10. In a machine of the character described, a bending rotor, a single reversible electric motor for imparting rotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, Vise block clamping means for holding a vise block against the tube as it is being bent, means for manually initiating a bending cycle operation of said motor, means for manually initiating a return cycle operation of said motor, adjustable means for automatically terminating the bending cycle when a predetermined degree of bend has been attained, means for automatically terminating each return cycle with the rotor positioned at the zero point, a mandrel engageable in a tube being bent at the point of bending to support the tube against fiattening, and power operated means automatically operable to retract the mandrel in the bent tube after completion of the intended degree of bending of said tube and for again and automatically projecting said mandrel to the point of bending prior to commencement of another bending cycle.

11. In a machine of the character described, a bending rotor, a reversible motor for imparting rotation to said rotor clockwise or counterclockwise, a radius block rotatable with said rotor, means for clamping a tube to one side or the other of said block to turn therewith, vise block clamping means placeable at either side of the rotor for holding a vise block against the tube as it is being bent toward the right or toward the left, means for manually initiating and automatically terminating a bendin cycle operation of said motor, and circuit controlling means for causing the motor to function in one direction or the other accordingly as said vise block clamping means is disposed at one side or the other of said rotor.

12. Ina machine of the character described, a bending rotor, a single reversible electric motor for imparting rotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to one side or the other of said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, means for manually initiating a bending cycle operation of said motor, means for manually initiating a return cycle operation of said motor, adjustable means for automatically terminating the bending cycle when a predetermined degree of bend has been attained, means for automatically terminatin each return cycle with the rotor positioned at the zero point, said vise block clamping means being placeable at either side of the rotor thereby to oppose a tube during the making of left or right hand bends, and circuit controlling means for causing the motor to function in one direction or the other accordingly as said vise block clamping means is disposed at one side or the other of said rotor.

13. In a machine of the character described, a bending rotor, a single reversible electric motor for imparting rotation in one direction or another to said rotor, a radius block rotatable with said rotor, means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent, means including electrical control devices for initiating a bending cycle 0peration of said motor, means for automatically terminating the bending cycle, a fluid pressure actuated means for operating each said clamping means, a single electrically operable valve. for controlling the operation of each fluid pressure actuated means for setting the clamping means prior to commencement of the bending cycle and for releasing the clamping means following completion of said bending cycle, and independent manually operable control means operable at will to control operation of said valve independently of the automatically controlled cycles of operation.

14. In a machine of the character described, a bending rotor; a single reversible electric motor for imparting rotation in one direction or another to saidv rotor; a radius block rotatable with said rotor; means for clamping a tube to said block to turn therewith, vise block clamping means for holding a vise block against the tube as it is being bent; a control circuit for controlling operation of said motor and including, means for manually closing said circuit to initiate a bending cycle operation of said motor, means for manually closing said circuit to initiate a return cycle operation of said motor, adjustable means for automatically terminating the bending cycle when a predetermined degree of bend has 'been attained, means for automatically terminating each return cycle with the rotor positioned at the zero point, and independent manually operable control switch means connected in said control circuit and operable at will to stop the machine independently of the automatically controlled cycles of operation.

15. In a machine of the character described, a

bending rotor, a reversible motor for imparting rotation to said rotor clockwise or counterclockwise, a radius block rotatable with said rotor, means for clamping a tube to one side or the other of said block to turn therewith, vise block clamping means placeable at either side of the rotor for holding a vise block against the tube as it is being bent toward the right or toward the left, an arm supporting said vise block clamping means and swingable about the axis of the rotor for placing the vise block clamping means at one side or the other of the rotor, means for manually initiating and automatically terminating a bending cycle operation of said motor, and circuit controlling means including a circuit conditiom'ng switch engaged by said swingable arm for causing the motor to function in one direction or the other accordingly as said vise block clamping means is disposed at one side or the other of said rotor.

16. In a machine of the character described, a

bending rotor, and clamp means for opposing a tube during bendin operations and comprising a movable clamp jaw, a standard, an arm on which said standard is mounted for limited sliding movement in any one of a plurality of selective positions, screw means for moving the standard a limited distance toward or from the rotor in any one of its selective positions, toggle link pivoted together and anchored at their ends to the standard and to the clamp jaw respectively, and a fluid pressure cylinder supported on the standard and having a fluid pressure reciprocated piston therein connected with the pivotal connection of said links.

ARTHUR L. PARKER.

HENRY E. HULL.

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