US2404234A - Drawing machine - Google Patents

Description

July 16, 1946.

W. E. KERR DRAWINGMACHI'NE Filed Aug.- 24, 1938 4 Shee tS- -Sheet' 1 was a u hm I [Va/ lam? 5 Kerr:

w. E. KE R R DRAWING MACHINE Jul 16, 1946.

4 Sheets-Sheet 2 Filed Aug 24, 1938 NY fig f 5% m E Q 5 wsw o E M 3 MN a 3 n Wa/lace A err. a W

J ly 1 946- w. E. KERR 2,404,234

' DRAWING mcnmp Fi ledAu 24, 1938 4 Sheets-Sheet a Wal/q'c Ker W. E. KERR DRAWING MACHINE Filed Aug. 24, 1958 July 16, 1946.

4- Sheets-Sheet 4 vw N v .55 3, P Q9, a3 2. a k v .a. fin %w uw v Wallace E. Kerr.

Patented July 16, 1946 UNITED STATES PATENT OFFICE DRAWING MACHINE Wallace E. Kerr, Youngstown, Ohio Application August 24, 1938, Serial No. 226,477

32 Claims. 1

This invention relates to a drawing machine of the kind in' which lengths of metal sections are drawn through restricting or forming dies for the purpose of reducing or forming the cross-sectional area or shape of the pieces. In machines for this purpose it is common practice to provide a die block, a frame or track extending away from the leaving side of the die or dies, a carriage' movable along the track and having means to grip reduced'end portions of the pieces extending through the dies, means for removing the pieces from the machine, as shown in my prior U. S. Patent #1940354, for example, and a moving chain to move the carriage away from the die block.

To efiect substantial economy in the produc tion of drawn shapes itis, of course, essential that the drivingmachine be automatic in its operation--requiring but one operator for its operation, and capable of wide flexibility in use While requiring a minimum of time to change over from one kind of operation to another. By the latter is meant the rearrangement of the machine for the production of shapes having different cross-sectional shapesor sizes and as this normally involves an interchange in themembers used to grip the reduced end of the stock extending through the die, th construction of the grip bit assembly on the carriage is such that the grip bits may be readily rearranged and interchanged with a minimum of delay. Inasmuch as the machine may be of sufiicient capacity to draw but a single length of bar or tube of one size and a plurality of lengths of smaller size the construetion enables either one or a plurality of such lengths to be simultaneously drawn, depending on the size and material of the stock being drawn and th manner in which the machine is set up. It is one object of my invention to provide a grip bit and grip bit operating assembly for use in a machine of the kind described in which the bits are of simple and inexpensive design and capable of being readily interchanged when preparing the machine for operation on different products.

Another object of the invention is to provide an improved construction for the grip bit operating assembly in which substantially th entire mechanism thereof is housed within the frame of the carriage thereby minimizing the danger of injury to such mechanism by impact between the frame and/or mechanism and other objects. This feature of design is accomplished without sacrificing any of the desirabl attributes concerning the ruggedness and ease of interchangement of the bits as mentioned abov and results in a machine requiring less. maintenance and having a higher long term efficiency'than any such machines heretofore devised.

A further object of the invention is the prothe block until the grip bits have effectively engaged the reduced ends of the bars or tubes ex-" tending through the dies of the block. These features are of importance since a quick return of the carriage decreases the time consumed in unproductive phases of the operation of the machine, the reduction in speed prevents injury to the carriage and die block assemblies due to shock, and the elimination of rebound of the carriage after contacting the die block enables the grip bits to engage the stock ends at a position very close to the dies thereby reducing the length of the reduced or pointed end required to be placed on each length of stock which reduced ends must subsequently be severed for scrap. By reducing the percentage of scrap evolved in the drawing process substantial economies are effected.

Yet another object of the invention is the provision of an improved meansto retain the chain engaging hook in retracted position when the carriage is returned to the die block and an improved mechanism for operating the grip bits upon the fall of the hook as the carriage reaches the die block whereby no undue stresses are imposed on any of the parts, wearing surfaces may be of substantial area, and the mechanism, as

a whole, may be subjected to continuous and heavy service with a minimum of repair and ad- I the cable and inwhich the cable maintains a fixed position axially of the driving sheave at all times whereby the elements may be of simple and economical design and delays incident to any carriage return mechanism failure may be substantially obviated.

These and other objects and advantages of the invention will become apparent from a consid.

, 3 eration ofthe following detailed specification and accompanying drawings of a preferred embodiment of the invention. Throughout the several views of the drawings, imilar reference numer- 3 V als designate similar parts; and

Figure 1 is a partial side View of a drawing machine embodying the principles of my invention; V

Figure 2 is a plan view of the'structure of Figure 1;

Figure 3 is a plan view, partly in section, of the grip bit carriage assembly of the machine of Figure 1;

Figure 4 is a plan View, partly in section, of 'a portion of a modified form of grip bit assembly, illustrating the manner in which the correspond.- ing assembly of Figures 2 and 3 is changedin order that the machine may simultaneously draw two bars or tubes instead of three as in Figures 2 and 3; g

Figure 5 is a plan view, partly in section, of a portion of a modified form of grip bit assembly, illustrating the manner in whch the corresponding assembly of Figure 2 and 3 is changed to draw but a single tube or bar at each traverse of the carriage;

Figure 6 is a plan view, partly in section, of another modified form of grip bit assembly;

Figure '7 is an end view of the grip bit carriage Figure 11 is a sectional view taken along the line Il-H of Figure 3; Figure 12 is a sectional view taken along the line |2l2 of Figure 2; and

Figure 13 is a wiring diagram, illustrating the energizing and control circuits for the carriage return mechanism.

Referring now.more particularly to Figures '1 and 2 of the drawings, the machine to which the various features of my invention may be applied consists of a bench l0 having a pair of spaced parallel tracks H on which travel the wheels 23 supporting the grip bit carriage frame Connected with one end of the bench H3 is the die supporting frame. generally indicated at 12 which is adapted to slidably receive the die block l3, theformer being'p'rovided with grooves l5 into which the ribs 14 of the latter move to prevent relative movement between the parts during the normal operation of the machine. Block [3 supports the restricting or forming dies is through which rods or tubes H are to be drawn and to initiate operation of the draw, the rods, tubes or other lengths I! are first provided with an end portion l8 reduced in diameter to pass through the openings in dies l6 for engagement by the gripping means carried by the frame 20. The latter is provided with a depending side member 24 to which the ends of the carriage moving cable is attached, one end having an adjustable connection 25 with the member whereby the tautness of the cable may be varied. In accordance with usual practice an endles and continuously moving chain 22, only a portion of which is shown, is utilized to transmit the power required to move the carriage 20 away fromthe die block l3 and draw the shapes being worked through the dies l6,'the chain 22 having a reach extending along the bench Ill between the tracks I! and continuously moving away from the dies 16. A hook 2i connects thegrip bit carriage with the chain 22 and in the normal operation of the machine the hook 2i automatically drops and engages the chain 22 as the carriage 20 reaches the die block l3 and disengages from the chain upon completion of the drawing operation thus enabling the cable 25 to return the carriage back to the dies. 7

The grip carriage assembly of my invention, including the preferably unitary frame membervZfl having alongitudinal recess for the reception of the hook 2!, as shown in detail in Figures 3 to 11, inclusive. Hook 2| is pivotally mounted on the transversely extending pin 28 and is provided on its upper surface adjacent its outer end with the attached member 29 having laterally ex- 7 frommember 29 allowing hook 2| to rotate about pin 28 and the hook to impinge on chain 22. Fork 29 is operated by rod 32 which pivotally connects with a pin 33 extending laterallyfrom the upper portion of the fork and which is biased by coil spring 34 toward'the die block end of the carriage to normally hold the fork in retracted position. Rod 32 is, in turn, actuated by the rod 35 the die block end of which is adapted to engage a projection 36 on block 13 as the carriage approaches the die block.

Carriage frame 2%] is provided at one end with a transverse recessed slot 35' into which'is adapted to slide the grip bit block 31 having inner flanges 38 fittin within the recesses to prevent longitudinal separation of the frame and block 31. Referring to Figure 3 which illustrates t grip assembly as set up to simultaneously draw three bars or tubes, the block 3'! is provided with three pairs of converging guide channels 39 each adapted to slidably receive a grip bit 49 having an angular disposed serrated portion 4! to rip the reduced ends IE of the bars or tubes being drawn. The channels-39 converge toward the outer face of block 37 whereby movement of the bits of a pairtoward said face cause the serrated portions thereof to move toward each other and securely clamp the intervening end I8 of. the bar or tube. The design of the parts is such that the outer side surfaces of the channels of a pair, which surfaces receive the entire thrust imposed by the clamping of the rod or tube portion l8, are uninterrupted through the length of the channels thereby increasing the wearing Surface and adding to the life of the assembly. The grip bits AG which may be constructed of stock which is square or rectangular in cross-section are. of simple design for economy of construction and inasmuch as they are of uniform cross-section they may be readily removed individually through their respective channel openings to the outer face of the block 31. For a purpose to be later described, eachof the grip bits adjacent its end opposite the serrated portion is provided with a vertically disposed bore 42.

'5 in their respective channels by the plungers 44 which abut the inner ends of the bits to move the same outwardly and by the inverted U-shaped connecting rods 45 the adjacent ends of which are received within the bores 42 to move the bits v inwardly. The outer faces of the plungers 44 and the adjacent faces of the grip bits 49 are plane and parallel thereby providing substantial contacting areas for the transmission of the forces required to move the bits into tight engagement with the stock being worked on. Plungers 44, which in the embodiment of Figure 3 are six in number, are mounted in parallel relation for sliding movement longitudinally of th bench ID in suitable bores provided in the frame 20. Adjacent the end of each plunger opposite its grip bit engaging surface is a collar 41 which is suitably secured to the plunger 44 and which is provided with a vertical bore 48 aligning with a bore 49 in the plunger to receive the other end of the inverted U-shaped connecting rod 45. 001- lar 41 being secured to the plunger moves the rod in accordance with the movement of the plunger. The collars 41 are each provided with a depending lug 5i] slidably receivedwithin slots 5| in the frame 20 to maintain the collars and consequently the rods 45 in proper vertical position.

Plungers 44 are urged to simultaneous longitudinal movement upon pivotal movement of the hook 2| by meansof the connecting linkage now to be described. Extending transversely of the upper portion of the frame 20 is the pin 53 on which is rotatably mounted the sleeve 54 having attached thereto the downwardly extending widely spaced arms GI and the centrally disposed spaced arms 55. Spanning the outer free ends of arms 55 is the pin 56 which is rotatably mounted in aligned apertures in the'arms and which is provided with a diametrically disposed threaded bore for the reception of a hollow screw 57. The latter is rotatably mounted on a threaded rod 59 which is rigidly connected at its lower end with a fork 59 pivotally attached at 60 to the hook 2| at a point adjacent the pivot 28. The upper end of screw 51 is provided with an attached collar 51? and a second collar 58 is screw threaded onto. the outer end of threaded rod 59'. By loosening collar 58, screw 51 through collar 51' may readily be. rotated thus providing an adjustment of the interval between pin 55 and pivot -50; A T

transverse member 62 having apertures 63 for the accommodation of plungers 44 is connected with the lower free ends of the arms 61' by the U-shaped links 64 which are rigidly attached at their one end to the transverse member 62 and which are pivotally connected, by means of pins 55, with the arms 6| at their other ends. As. shown in Figures 9 and 10, the frame 20 is provided with a cavity 66 of sufficient size to accommodate member 62 and to allow said member a limited movement longitudinal of the bench It] with respect to the fram 20. A coil spring 61 is interposed between each collar 41 and the transverse member 62 and a second set of coil springs 68 are interposed between the member 62 and the enlarged ends 69 of the plungers 44. It can therefore be seen that longitudinal movement of the member 62 along the axes of the plungers 44 causes the plungers and consequently the grip bits 40 to move along their longitudinal axes and the bits to move to their operative or inoperative positions. As shown in Figure 3, the links 54 are positioned intermediate certain of the plungers 44 so as not to interfere with the proper operation of the latter.

' Returning to Figures 1 and 2 of the drawings, the apparatus provided to returnthe grip bit carriage to the dies and to move the carriage independently of the chain 22 when no load is imposed includes the cable. 25, as,.mentioned above, which is driven by a novel driving arrangement now to be described. I provide a driving motor H having an attached speed reducing unit 12 the driven shaft 13 of which has keyed thereto inner and outer driving disks l4 and [5, respectively. See Fig. 12. .Disks l4 and 15 are urged toward each other by a spring 16 interposed be-' tween a nut H on the outer end of extension 18 of shaft 13 and the outer surface of disk 15.

of sheave 30 and the inner faces of the disks mentioned. Spring '56 is so adjusted that Sllfficient power to move the carriage may be transmitted through the friction clutch thus provided but if excessive resistance is, encountered, the

clutch will slip. A single groove sheave B3 is supported on an inclined axis on one side of the driving sheave as and a second single groove sheave 84 is mounted on an inclined axis on the other side of sheave 8B. A pulley 85 is mounted adjacent the end of the bench l0 opposite the die block and a second pulley 86 is mounted adjacent the die block; Beginning with that end of cable 25 fixed in relation to member 24 the cable may be t'racedover pulleytG, sheave 80, sheave 84, sheave 83, sheave 8e, pulley 85 and back through adjustable connection 26 to member 24. The purpose of the inclined axes for sheaves 8'3 and 84 is to .provide aligning guide surfaces between the cable leaving increment of one sheave and the cable entering increment of the subsequent sheave. The arrangement provides a length of contact between the cable 25 and the driving sheave equal to or. slightly greater than the entire circumference of the sheave 80 thus providing a drive of sufficient capacity to quickly move the carriage along the bench. Also the arrangement enables the drive to be accomplished by the use of' but two parallel grooves in the driving sheave thereby dispensing with any movemade lighter in construction and will be less likely to be damaged in use.

The control circuit for the grip bit carriage return motor H is illustrated schematically in Figure 13. Motor His of the reversing type andis provided with a magnetic brake I12 of the usual kind in which the braking force is applied by a spring and released by a solenoid, as 92, which is energized simultaneously with energization of the motor. A normally closed limit switch 88 having an operating arm 89 adapted to be engaged by depending member 24 of the car-- riage" is positioned on the bench If] a number of feet from the die block [3 and a second double throw limit switch 9d having an operating arm 9! also adapted to be engaged by depending member 24 is positioned adjacent the die block in such manner thatwhen the outer face of block closed position as viewed in Figure 13. A third,

limit switch 94 having an operating arm 94a operated; by a member Stir-"(see Figure 12) through friction clutch 8:35 driven by sheave, 83

is adapted to bev operated upon reversal or direction of movement. of the. cab1a25. The. operation ofathis assembly is such that upon a. change in the direction of movement. ofthe. cable, and consequently of sheave 83, the member 8311 rotates until the switch arm 94a. is thrown to its other limiting position whereupon member 83a stops.-

further rotation of 831* being permitted by the frictional connection between 33, and..83a

Figureg13 illustrates. the conditionjpf; the controls; immediately after the; return switch S2 has been manually actuated and the carriage is returning to] the dies.

IIlBb,*solenoid S conductor Hi5, I85a-,. switch S2, conductor Mia, III, H2, normally closed Energization of solenoid S05. closed the switch S5 and SM thereby switch SI, and back to line.

energizing the return windings of the motor thru line, conductor H36, Ifific, switch S5a, conductor 96a, 96, motor 1|, conductor 91, 98, I3ila, switch S5, conductor I30, H9, IE6, 2, switch SI, and back to line. Simultaneously a holding .circuit for solenoid S05- consisting of line, conductor I06,

Actuation of S2 estab-; lished the relay circuits-line, conductor I66, lllfia,

S-Ea: to, open thereby opening the motor energizing circuit. Opening of switch S5: also breaks the relay'circuit-line, conductor I31, I26, solenoid S08, conductor H2, 98, I3fia, S5, I130, II9, H6, H2, SI, and back to line; deenergizing solenoid S08 and opening switch S8 which switch maintains an energizing circuit..line, switch SI, conductor H2, H6, I24, brake releasing solenoid 92, conductor 122, I23, S8, I25, I33, 1.3L and line; for operation of solenoid 92 and release of brake Consequently; as the carriage reaches switch 88, and motor 1! is. deenerg-ized and the brake I12 is applied which in addition to-applying its efiect to the motor 1'1 per se also acts on the cable thereby exerting a braking action on further movement of the carriage.

Inasmuch as the carriage assembly is of' considerable. weight substantial inertia'is inherent in the same when it is movingand it will continue to drift, some distance after motor H is deene-rgized and brake I12 is applied. Brake I12, and, if necessary, friction drive M, 15:, 80, are so ad justed that the carriage will drift to. substantial engagement with the, die blockv orat least: until circuit.line, H16, late, 8.5a, 96a, 96, motor 1!,

98, mm, 5, I N9, M N2, S a d ba to line-which ener'giz'ation of motor 1-! will move the carriage into. positive engagement with the die block and maintain the. engagement until the main draw chain 22, through hock 2|, begins to .ccmnleted the en agement of red. 35. with. pro ection 35 moves. he t t; 29'. cpu terc sr isc re: ea m atch. 3:30, and. allq ine, hook I befa l onto c ain 22.. ee e 56 t be ro- 9 wnsequ ntly o a in M nd m v nalinks 6 to r-dine. s pr iis, es. he tran ve s member, .2- s cmme t th the inks i Wi 1-a be mo ed. owarclt e rip hit end of he Qa aeeami. rq sh p ing acting on plungers 44' it will. urge the plungers t ward he sam nd of e ar age As. c ear y shown in Figures, such movement of the plungers W l move the r p. b t 40 al n t e r ha nels a d e. i of e ch pair ll move towar ach other alld securely clamp the stock ends; I3 to the carriage. Now as the bight of the hook 2! drops intov a, dwell of the chain 22, if it did not do so initially, the carriage, and consequently the stock will be drawn along the bench. During that in terval between the time the carriage, reaches the die block and the time the chain 22, through hook 2! begins to move thev carriage away from the block the pressure, contact between the carriage and the block is maintained through. cable 25 by motor 1!, the friction clutch 14, 15,811,8I (Figure 12) slipping.

To prevent energization of motor drawing cycle, the switch normally returns to the position shown in Figure .3 and upon sllC i movement and consequent reversal of direction of movement of cable 25, switch 9,4 will close. As shown in Figure 13, the switch 9t! deenergizes solec d. 5 y open ng c rcui th cuehna .96.,

' thereturn motor control circuit I provide ar energizing circuit.lin e, I05, 15d,- SSa, II 4., 9,5,

us, 1se.c.,,sa.|so.b, M9, M15, uz, s1, an back to line. Upon release of switch S4 the circuits mentioned are opened and the motor i deenergized and the brake I12 applied thereby providing aver-y sensitive carriage positioningcontrcl, To

. release brake. I12. upon such motor energization the closing of switch S5, energizes solenoid So! through line, III-ll, IIJ, Sol, I31, Mile, S6, I332), 1 2 an l e i h so en d closes switch S! providing a circuit-lineSj, H2, H6, I24, 92, :22, IZI, 5, s1, U8, I33, I31, and. line-T op si g forward movement of the carriage during the thereby energizing brake releasing solenoid 92.

The carriage may be controllably moved toward the dies by depressing manual switch S3 which establishes the circuitline, I06, Iilta, I061), S05, I05, I53, me, S3, H0, Hi l, H1, H2, SI, and line-and closes switch S5 and 84a closing the motor energizing circuit defined above. Simultaneously solenoid S08 is energized thruline, I3I, I25, S03, :32, 88, IBM, S5, i330, IiE, I I6, I I2, and SIclosing switch S8 thereby energizing brake releasing solenoid 92 through line,

SI, H2, H6, I24, 92, I22,I23,SS,I25,133, I3!, and. line. Upon release of $3 the circuits completed thereby are opened, the motor deenergized and the brake applied. A fourth. manual switch SI is rovided to stop the carriage when moving as a result of energization of motor I! by previous closure ofSZ or bythe failure of switches S3 and S4 toopen upon release. Opening of Si breaks the holding circuit described aboveand opens any circuit established by actuation of manual switches, S3 and S4.

In operation, the lengths of stock are fastened to the carriage in the manner and by the mechanism described above and as the chain 22 takes the load it rises to the position shown in Figure 1 by reason of the elevation of pivot pin 28 and thereby lifts the hook 2|. up sufficiently to position member 29 above the'shoulders 30 of mem ber 29'. Spring 34 draws member zeinto retracted position upon disengagement of rod 35 with projection 36 and in this position of the parts the draw continues until the stock I! has passed through the dies. As the stock leaves the dies the carriage will accelerate ina forward direction causing the chain to fall awayfrom the hook 2| which will be maintained in upper position by the member 29 resting on shoulders 30. Inasmuch as the transverse member 62 will have moved forwardly when the hook raised with the chain 22, the springs 61 between member 62 and collars 41 will be compressed and as the tension on the stock I? ceases thereby stopping the outward pull on the grip bits 40, the collars 41 and plungers 44 will move in a direction away from the grip block 31 and by reason of the connecting rods 45 the grips bits will also be moved in the same direction to open the pairs thereof and allow the stock ends I! to be removed therefrom. The bits remain in open position until the hook 2| again falls by engagement of rod 35 with the projection 36 or by manual manipulation of member 29', the projecting pin 33' of which provides a hand grip member.

To provide means to raise the hook 2| during forward movement of the carriage irrespective of the load and tightness of chain 22 a pair of cam members I4!) are positioned on opposite sides of the chain 22 adapted to be engaged by a pair of members I4I secured to and depending from opposite side faces of the hook. If the hook is down when cams I are reached, the lower surfaces of depending members I4I ride up the inclined upper surfaces of members I40 thereby raising the hook sufficiently to permit attached member 29 to snap over the shoulders 30'of member 29' and retain the hook in raised position.

A dashpot I44 acting through pivoted lever I engageable by the carriage as it nears the die block may be employed to cushion the impact between the carriage and the die block.

As stated above, the grip bits 40 are carried in a block 31 which is slidably mounted in the carriage frame 20. Block 31 is retained in position,

in the frame by the pin 31 which passes down the carriage frame. As apparent from Figure "3 the frame 20 is provided with openings allowing ready access to the rods 45. Block 31 may be replaced, for example, by a block 3' as shown in Figure 4 in which but two pairs of grip bits 40I are included. The set up may be used to draw stock I8I of larger size than it would be possible to draw in a triple machine. Certain of the plungers 44 and certain of the collars 41 and rods 45 would be utilized to operate the grip bits 40I. Aside from the withdrawal of rods 45 which is an exceedingly simple operation no parts of the grip bit operating mechanism need be touchedin' the changing of individual grip bits or in the changing of the grip bit block assembly. In Figure 5there is shown a block 312 which houses but a single pair of grips 402 for operation on very large or heavy stock. When assembled with the other parts of the carriage, a pair of plungers 44 and a pair of rods 45 are utilized for the actuation of each of the grip bits 402 thus insuring adequate force for the actuation of the heavier bits. In each of three modifications thus far described the operation is the same.

Figure 6 illustrates a modified form of carriage in which the grip bits 403 are not mounted in a removable block but are mounted in guides provided in the carriage housing 203. Transverse member 62 is dispensed with and the collars 623 on each of the two plungers 443 are connected 7 directly with the links 64. As in the other em- The adjustment 56, 51, 58 may vary the 'position ofthe transverse member 62 or the collars 623 with respect to the carriage frame and may consequently alter the position of and interval or intervals between a pair or pairs of the grip bits when the hook is in raisedposition in which position of the parts the grip bits move about the stock ends projecting through the dies. If the stock is small in cross-section the pairs of bits are moved closer together to insure tight gripping upon fall of the hook and if the stock is large in cross-section the grip bits are moved further apart. This is the only adjustment necessary" for the proper operation of the grip bit operating mechanism and the design of the assembly permits this adjustment to be positioned in a readily accessible location. Incidentally this is the only element of the mechanism which projects beyond the general outer contour of the grip bit carriage assembly, practically all the parts thereof being located within the casing or housing in nested and protected positions.

It can thus be seenthat I have provided an 7 improved metal drawing machine which accomplishes the objects initially set out. The devised control for the movement of the grip bit *carriage enables the machine to be operated at higher productive speeds and allows a reduction to be effeet-ed in the amount of the stock utilized in the provision of the requisite reduced end for each length'thei'eby substantially reducing the scrap losses incident to the operation of the process. Assuming a constant supply of pointed stock to be made available atthe dies by any of the means well known in the art the drawing machine operatonneed normally to perform but few operations during each drawing cycle as the momentary depressing of the return control switch S2 upon completionof a draw will result in automaticcontrolof the subsequent movement of the carriage in the manner described above. The grip bits iwhich must be replaced from time to time because of normal Wear are very simple in design and are consequently economical to construct. The bits may be readily replaced individually and the entire grip bit assembly may be readily removed from and inserted in the carriage thereby facilitating the setting up of the machine for operation on diiierent products. The interchanging of theindividual bits and of the bit assemblies requires little technical glinow ledge on the part of the operatorand no special tools and the same may be accomplished without disturbing the more complicated parts of the -machine. By positioning the latch 2S-30 near the center of the unsupported mass of the hook 21,

on said carriage for movement and closed positions, a motion transmitting e'le ment connected with and moved by first said being removable without disturbing said'rfirst mentioned means. 7

2. In a drawing machine, a carriage havmg' guide surfaces thereon, grip bits carried by said carriage and slidable along said surfaces into engagement with the stock to be drawnfcontrolled means on said carriage to move said grip bits into engagement with said stock, said'means applying a resilient force tosaid grip bits, and means including quickly removable links con- ,necting said grip, bits and first mentioned means for moving said grip bits in the opposite .direc- 7 tion.

a 3. In a drawing machine, the combination :of a carriage having an operating member therea on, a stock engaging grip bit movably mounted into open mentioned member, means to transmit motion from said element to said grip bit in a closing direction, and a movable means connecting said element and said grip bit to transmit opening movement to said grip bit, said last mentioned means being removable without disturbing said first mentioned means.

4. In a drawing machine, the combination of a carriage hav-ing a member movable upon en- Important features of my invention include i the arrangement and design of the grip bits and the grip bit operating mechanisms. As the grip bits are individually resiliently urged to closed positions by the springs 58 acting through their respective plung'ers dd, inaccuracies in the shape {and disposition o'fthe pointed ends of the stock to be drawn will not efiect theoperation of the gripping assembly for the reason that in all instances each of the gripbits of .a gripping pair will be independently moved into pressure engagement with the end portion of the stock. prings fifiperform the additional function of cushioning the shock transmitted .to member 62 by thesuddenmovement .of the grip bits when the last .of the stock leaves .thedie. It should be observed that the grip bit operating elements 44, c5, .41, a2, .61 and 6.3 are ru eedly mounted in protected positions in the body of the frame 21! and thus are capable of withstanding severe conjditions of service without failing. While I have specifically described these elements as being operable upon. movement of a c ain engaging hook it should be obvious that other m ns ma be employed to transmit drawing m ement to the carria e and that other m chan sm may be employed to actuate the said elements.-

The above specifically described embodiments of my invention should be considered as illustrative only as obviously many changes may be made therein Without departing from the spirit or scope of my invention, the extent of which is indicated by the subjoined claims.

What I claim is: I 1. In a drawing machine, the combination of a carriage having a member movable upon engagement with anwelement independent of said bar- ;riage,a stock engaging grip bit movably mounted on said carriage for movement into open and .closed positions, .a motion transmitting element connected with and moved-rby said first mengagement with an element independent of said -carriage,'a second member on said carriage normally located in an elevated position and adapted when "moving downwardly to originate a moving force, a third member mounted on said car- 7 riage and adapted to move rectilinearly, means connecting said first and second members whereby actuation of the former will result in downward movement of the latter, means connecting said second and third members whereby movement of the second member will be transmitted characterized in that said connection between.

said second and third members is resilient whereby the force furnished by, said second member will'zbe resiliently applied to said grip bit.

-6. In a drawing machine, a grip bit carriage comprising a frame, a block removably received 1 within said frame, said block having a pair of converging channels for the guidance and slidable support of a pair of stock engaging grip bits, said channels extending through the outer face of said block adjacent their point of convergence turbing said means.

for the reception of an extended end-of the stock being drawn and for the insertion and removal of the grip bits individually, ancl'means movable relative to and carried with the carriage and engaging said grip bits for moving said grip bits toward said face, said block and bits being remov able from said carriage as 7. In .a drawing machine, a grip bit carriage comprising a support having a pair of converging channels for the guidance andslidable support of a pair of stock engaging grip bits, said channels extending through, the outer face of said support adjacent their point of convergence for the reception of an extended end of the stock being drawn and for theinsertion and removal of the grip bits individually, means carried with said carriage for moving said bits toward said face, removable means for moving said bits away from said face, said bits being removable from Q 7 said support upon the removal of said removable V a unit without dis- 13 means without disturbing said first mentioned means.

8. In a drawing machine, a grip bit carriage comprising a support having a pair of converging .channels for the guidance and slidable support of a pair of stock engaging grip bits, said channels extending through the outer face of said support adjacent their point of convergence for the reception of an extended end of the stock being drawn and for the insertion and removal of the grip bits individually, means carried with said carriage for moving said bits toward said face, means connected with said first mentioned means to move said bits away from said face, said second mentioned means being readily removable without disturbing said first mentioned means to permit the bits to be removed from said support.

9. In a drawing machine, a grip bit carriage comprising a frame, a block removably mounted in said frame and carrying a plurality of stock engaging grip bits, means within said frame to move said grip bits into engagement with said stock, said block and grip bits being removable as a unit from said frame without disturbing said means.

10. A grip bit for a drawing machine having a grip bit carriage with divergent guide surfaces thereon to slidably mount the grip bits and controlled means having plane surfaces to engage and resiliently urge the grip bits into engagement with the stock; comprising an elongated member of substantially uniform cross-section throughout the major portion of its extent and having a serrated surf ace for engagement with the stock to be drawn and a plane surface for engagement with said plane surface of said coacting grip bit urging means. i p

11. A grip bit for a drawing machine having a grip bit carriage with divergent guide surfaces thereon to slidably mount the grip bits and controlled means having plane surfaces to engage and urge the grip bits into engagement with'the stock and quickly detachable links interconnect ing said first mentioned means and the grip bits; comprising an elongated member of substantially uniform cross-section throughout the major portion of its extent and having a surface for engagement with the stock to be drawn, a recess for the reception of a portion of one of said links, said recess extending substantially normal to the direction of movement of thegrip bits.

12. .In' a drawing machine, a grip bit carriage comprising a frame, movable means mounted thereon, a plurality of plungers slidably mounted in said frame, .said plungers having outer plane surfaces, means connecting said plungers with said movable means whereby movement of saidmovable means results in longitudinal movement of said plungers, a plurality of pairs of stock engaging grip bits each having a plane surface adapted to beengaged by the outer plane surface of a contiguous plunger, said plungers being so disposed that grip bits variable in number of pairs, size and disposition may be engaged and operated thereby.

13. In a drawing machine, a grip bit carriage comprising a frame having movable means mounted thereon, a plurality of plungers slidably mounted in said frame, means connecting said plungers with said movable means whereby move-- ment of said movable means results in resilient pressure being applied to said plungers tending to move the same longitudinally, a plurality of stockengaging grip bits adapted to be engaged and individually moved by said plungers, said 14 plungers being so disposed that grip bits varl able in number and disposition may be engaged and operated thereby,

14. In a drawing machine, a grip bit carriage comprising a frame having movable means mounted thereon, a plurality of plungers slidably mounted in said frame, means connecting said plungers with said movable means whereby movement of said movable means results in resilient pressure being applied to said plungers tending to move the same longitudinally, a plurality of stock engaging grip bits adapted to be en-- means results in independent movement of the plungers as determined bythe resistance encountered by the respective plungers, and a plurality of stock engaging grip bits adapted to be.

engaged and individually moved by said plungers.

16. In a grip bit carriage for a drawing machine a pair of stock engaging grip bits mounted for movement toward and away from each other, a hook mounted for pivotal movement about a horizontal. axis which is eccentric with respect to the center of mass of the hook, means to latch said hook in upper raised position, and linkage between said hook and said grip bits whereby upward movement of said hook moves said grip bits apart while downward movement of said hook moves said grip bits toward each other, said linkage including a unitary adjusting element which when adjusted in one direction is operative to move said grip bits toward each other and when adjusted in the opposite direction is per raised position comprising a member support-' operative to move said grip bits further apart independent of movement of said hook.

- 1'7. Apparatus according to claim 16 further characterized in that said linkage includes alink connected with said hook eccentrically of the pivot pin thereof, said unitary adjusting element constituting a portion of said link and being operative to vary the eifective length of said link. 18. In a drawing machine, a grip bit carriage comprising a frame having a hook pivotally mounted thereon and movable by gravity in a generally vertical plane from upper to lower positions, and means to maintain said hook in upper raised position comprising a member supporting said hook at substantially. the center of its'otherwise unsupported mass, said member being carried with said frame.

19. In a drawing machine, a grip bit carriage comprising a frame having a hook pivotally mounted thereon and movable by gravity in a generally vertical plane from upper to lower positions, and means to maintain said hook in uping said hook at or adjacent its center of mass or on the opposite side of said center from the pivotal axis of said hook.

20. In a drawing machine, a grip bit carriage comprising. a frame having a hook pivotally mounted thereon on a transversely extending pivot pin, a plurality of plungers slidably mountedin the frame rearwardlybf said pin, means connecting said plungers with said hook whereby f pivotalmovement of s'aidhook results in resilient pressure being applied to said plungers tending to move the same longitudinally, said connecting means including linkage extending underneath said pin, a plurality of stock engaging grip bits slidably mounted in said frame and adapted to be engaged and operated by said plungers, substantially the whole of said plungers, connecting 1. means and grip bits being housed Within said frame in protected positions. 7

21. Structure according to claim further including adjusting means to vary the interval of said connecting means, said adjusting means exrality of movable stock engaging grip bits mounted in said frame 'rearwardly of said axis, and

H means depending below said axis'for connecting said'hook and said grip bits whereby pivotal movement of the hook will result in movement of the grip bits and the said means is in protected position within the frame.

23. A drawing machine comprising a die block, a bench extending outwardly fro-m said block, a

gripbit carriage. movable along said bench tov ward and away from said block, means to move the carriage toward the'die block, means to brake such movement as the carriage approaches the die block, means to urge said carriage toward adjacent said block, and means rendering the I said block as saidcarriage reaches a position I 24. A drawing machine comprising a die block,

a bench extending outwardly from said block, a

grip bit carriage movable along said bench, means to move the carriage under load away from said 3 block, independent means to move the carriage toward said block, means to brake the movement a toward the block as the carriage approaches the block, means to urge said carriage into engagej ment with said block as said carriage reaches a 1 position adjacent said block, means to automatically connect the first mentioned means with i the carriage after the carriage reaches the block, 1 and means operable upon initiation of movement away from the block to render saidmeans Y to urge inoperative,

'25. A drawing machinev comprising a die, a

' I bench extending outwardly from said die, a grip I bit carriage movable along said bench, means i to move said carriage'toward said die' comprising 1 a cable, means tomove the carriage under load away from said die, means including said cable to 1 urge the carriage toward the die, and means responsive to the initiation of movement of said i carriage away from said die to render said means to urge inoperative.

26. A drawing machine comprising in combina load away from said block, movable grip bits on said carriage, means to move said bits to material engaging positions, independent means to move said bits to open inoperative positions, means to said block as said carriage reaches a position adjacent said block, means to automatically con- 1 tion a .die block, a bench extending outwardly i from said block, a grip bitoarria'ge movable along I said bench, means to move the carriage under 16 heat the first mentioned means with the carriage after the carriage reaches the block, and means operable upon initiation of movement away from the block to render said means to urge inoperative.

'27. A drawing machine comprising a die block, a bench extending outwardly from saidblock, a grip bit carriage movable along said bench toward and away from said block, means to move the carriage toward the die block, means to urge said carriage toward said blockas said carriage reaches a position adjacent said block, and means rendering the urging means substantially inoperative during movement of said carriage away from said block. a

28. A drawing machine comprising a die, a

bench extending outwardly therefrom, .a grip bit carriage movable alongsaid bench, means to move said carriage comprising a cable'secured to said carriage, a pulley at each end of said, bench, a cable driving sheave having at least two sheave, the other groove of the driving sheave,

the other pulley and thence back to the carriage whereby the driving sheave support is substantially relieved from stress arising from static tension in the cable and the stress resulting from driving tension in thecable is applied at a constant point along the axis of said driving sheave.

29. I-n-a drawing machine having a die, a bench extending outwardly therefrom, and a grip bit carriage movable along said bench; means to move said carriage along said bench comprising a unitary cable secured'to said carriage, a cable driving sheave having at least two'sp'aced parallel annular cable engaging tracks thereon, a sheave having at least one annular cable engaging track thereon on either side of said cable driving sheave; said cable entrained'in series over one of the tracks of the driving sheave, one of the tracks of one of the second mentioned sheaves, one of the tracks of the other of said second mentioned sheaves, and one of the other of the tracks of the cable driving sheave; whereby the driving sheave support is substantially relieved from stresses due to static tension in the cable and the stress re- 5 sulting from dynamic tension in the cable is applied at substantially a constant point along the axis of the driving sheave 30. In a drawing machine having a bench and a grip bit carriage movable along'said benchj means to move said carriage along said bench comprising a, unitary cable secured to said. 1031- in, said cable in either directionof rotation of 7 said driving sheave does not'vary longitudinally along the axis of the driving sheave.

3 1. In adraw head for operation in a mecha nism of the class described,attachingmeans for positively engaging said head with a drawing I m'ember, sliding jaw members adapted to engage the work to be drawn, an operating member for each of said jaw members, linkage means actuated by said attaching means for operating said operating members, and spring means inter-connecting said linkage means and said operating members, said linkage means, spring means and operating members being adapted, on movement of said attaching means, to simultaneously move all of said jaw members toward the work, and said linkage and spring means being adapted to thereafter independently move any said operating member and its jaw member after any other said jaw member has positively engaged the'work.

32. In a drawhead for operation in metal drawing apparatus having a workhead and means supporting said drawhead for movement away from and toward said workhead, a pair of relatively movable jaw members adapted to engage a stock piece to be drawn through said workhead, an operating member for each of said J'aw members, mechanical power generating means carried on said drawhead, linkage means actu- 18, ated by said power means upon activation thereof for operating said'operating members, lost-motion urging means interconnecting said linkage means and said operating members whereby upon activation of said power means and the subsequent arrest of movement of one of said jaw members by contact with said stock piece the other of said jaw members is continued to be urged in a direction tending to close onto said stock piece, and a control device on said drawhead for automatically effecting the activation of said power means thereby automatically effecting said closure of said pair of movable jaw members onto said stock piece upon said drawhead moving to a predetermined position adjacent said Workhead.

WALLACE E. KERR.

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