US2980238A - Draw buggy - Google Patents

Description

April 18, 1961 E. w. NILSSON DRAW 'BUGGY 2 Sheets-Sheet 1 Filed May 20, 1958 N QE INVENTOR EINAR W.

NILSSON WORNEY April 18, 1961 E. w. NILSSON 2,980,238

DRAW BUGGY Filed May 20, 1958 2 Sheets-Sheet 2 FIG. 6

FIG. 5

\ L Q N INVENTOR EINAR w. NlLSSON ATTO EY United States. PatentO 2,980,238 DRAW BUGGY Einar W. Nilsson, YoungstowuyOhio, assiguor to The McKay Machine Company, Youngstown, Ohio, a corporation of Ohio Filed May 20, 1958, Ser. No. 736,622 3 Claims, c1. 205-3 and carries gripping means for engaging andholding', the

reduced or pointed end portions of the metal sections which are initially loaded to project through the dies. The carriage, or draw buggy as it is commonly referred to in the art, is adapted to grip the projecting ends of the metal sections and then is moved outwardly, along the frame or bench, by means of a hook mounted on the draw buggy engaging a link of a continuouslydriven chain, for example, thereby drawing the metal sections through the dies to reduce and/0r shape the same. Such 1 mechanism may also include means for removing the drawn metal sections or stockfrom the draw buggy, meansv for returning the draw buggy to its starting position adjacent the die block, automatichandling equipment for loading the pre-pointed metal sections into the die block and for removing and handling the drawn metal sections or stock from the fram as well as suitable "control apparatus'for effecting generally autorn'aticvoperation of the drawing mechanism in the desired manner. The general arrangement of this type of drawing-mechanism is shown and described in the prior United States Patents to Kerr and Andrews, Jr., et al., Nos. 2,404,234 and.

2,331,953, respectively, which are representative of the prior practice in the art and are made of record "for those desiring a more detailed description of thelsame,

It is theprimary or ultimate object of the present in vention to provide an improved draw buggy of-the kind. adapted to be employed'with the above described type of,

drawing mechanism. Whenever alplurality of dies a're employed and the'draw buggy'fno'u'nts a plurality of means for gripping the pre-pointedT ends of, metal sectionsi.e.-in multipleidrawingfloperations it is, necessary that all of the'projecting reduced ends of thernetals'ections be properly gripped prior to movement of the draw buggy and the inability of prior'art apparatus'to satisfactorily meet this condition has resulted in several seriousfproblems. Failure of the gripping means to properly engage and grip one or morefof the pre-p'ointedends of" the meta l sections or stock is a frequent'cause ofdelay in drawing operations and an interrupted draw may cause undesirable marking of the stock, T heseproblems have prevented, to a certain extent, the realization of theef-x;

ficiencies and economies inherent in drawing'mechanisni limited the employment thereof and. methods of this general type and have jsoniewha t It'is 311611161 object or the invention)mismviaeaarw different metal sections in affastiand efiicient C6 Patented Apr. 13, 1961 2a a buggy wherein the means for gripping the reduced ends of the metal sections is actuated to firmly and positively grip the same prior to the movementof the draw buggy to draw the metal sections through the dies. As will be more fully apparent, the gripping means is actuated to grip the ends of the metal sections prior to the release of the hook carried on the draw buggy which engages the; continuously driven chain. v i

A further object of the invention is to provide appara tus of the character described wherein a separate driving means for actuating the gripping means is mounted directly on the draw buggy and operative when energized to positively move the gripping means into gripping engagement with the ends of the metal sections prior to movement of the draw carriage. In accordance with this object, the draw buggy mounts an felectricgear motor operating through new and novel linkage means to close the gripping means in relatively independent. fashion whereby each of the metal sections is firmly gripped prior to drawing. 7 I f j Another important object of the present invention is to provide improved means for powering or energizing the separate driving means mounted on the draw buggy when the same is adjacent the die block. The draw buggy mounts a forwardly projectingconnector and the dieblock mounts a mating connector-so that when the draw buggy is against the die block the driving means is energized to actuate the gripping means, It will be noted that this arrangement is parti cularly advantageous since the driving means is energized at exactly the right time and remains energizecl ,to insure'positive gripping of the projecting ends of the metal s'ectionsuntil the actual drawing operation commences'and the draw buggy moves outwardly from the dieblo clc, l

A still further object of the invention is to provide im v proved gripping means for a draw, buggy. Such gripping means comprises a plurality of sets of inwardly-converg' inggripper bits and improved linkage means for moving the sets of bits in relatively independent fashion to grip the pre-pointed ends of the, metal sections. In this manner'each 'ofthe ends of the strip sections is firinly gripped irrespective'of diiferences in'the sizes and shapes of the saidends. ,j I, a Yetanother object of the present invention is to provide gripping means'of the type indicated whichris char".- acterized by its almost complete lack. of sliding friction; Inrprevious' gripping means the amount of sliding 'fric-' tion in the gripping means at thetime theends of the metal sections are beinggripped isconsiderableandlthis' sliding friction "may prevent ,a good" gripping action,

Another object of the invention istoprovideigrippirig" means, which is easily and readily 'rernovedtor freplacei mentland/orrepairs. In this manner theidrawirigjmech anism. may beused ior forming or shaping severaldiffer ent sized o'r shapedmetal sections at one, timegorfjthe ,enre r pp "me n y egc a 'g ditf ct ii I I anisrn An ancillaryobject of the present, invention'is to pro; vide a draw bu'ggy and gripping me'ans therefor having the characteristics outlined above ,which is of simplified andeconomical construction but it is yet welladaptedtd thereby providing more versatile drawing in withstand continuous mill-type operations. Q, 7 The above, as well as other objects'and ,advanta'g' the invention", will become-more readily apparent upforif consideration of the followingpspeciiication andacc'om{ ,panying drawing wherein there are disclosed certainfil lustrat ed, embodiments constructed inlacco rdance with-the: I

with: aprotective cover "for a portion of the driving teachings of lthe presentfinvention;V i 511 dr w Figure l isz'aplan view* of anfimpr ovedfdraw; uggy,

teachings of the present invention;

Figure 2 is a side sectional view of the draw buggy taken along the section line II-II of Figure 1;

Figure 3 is an enlarged fragmentary end sectional view taken along the section line lII- III of Figure 1;

Figure 4 is a fragmentary plan view of the forward end of a draw buggy depicting the improved gripping means;

Figure 5 is an enlarged fragmentary plan view showing specifically a portion of the gripping means; and

Figure 6 is a side sectional view taken along the section line VIVI of Figure 5.

Referring now to the drawing, and initially to Figures 13 thereof, the reference numeral 10 designates a generally rectangular unitary frame formed with bifurcated projections 11 adjacent each corner thereof that are spanned by transversely extending axles 12 which in turn journal wheels 13 by means of bearings 14. The frame 10 is thus supported for movement by transversely spaced pairs of longitudinally separated wheels. The frame 10 has a large rectangular recess 15 for mountingthere on a gripping means 16, a driving means 17 for actuating the gripping means and a rearwardly projecting hook 18, all of which will be hereinafter more fully described. The draw buggy is adapted for longitudinal movement on a frame or bench 19 having spaced tracks, not particularly shown, for the wheels 13 and mounts a continuously driven chain thereon, also not shown. The bench 19 extends longitudinally in the direction of drawing from a die block, indicated schematically by the reference numeral 20, mounting a plurality of dies. In the normal and intended operation of such drawing mechanism the metal sections are first loaded into the dies with the reduced ends thereof projecting forwardly of the face of the die block 20. Then the draw buggy is returned to abutting relation with the die block and the driving means is actuated to move the gripping means to positively engage the protruding ends of the metal sections. After, and only after, the ends are properly gripped the hook 18 drops and engages a link of the driven chain and the draw buggy is moved outwardly of the die block thereby drawing the metal sections. When the drawing is completed the metal sections are removed, the hook 18 is disengaged from the driven chain and the draw buggy is returned to a position adjacent the die'block 20 for another drawing operation. It will be observed that the above described operation is well adapted for automatic and continuous cycling.

Considering now the gripping means. 16 shown in Figures 1 and 2 of the drawing, the forward ends of the frame 10 terminate in hook-like inturnedportions 22 which engage vertical channels 23 formed on the oppositeendsof a grip bit block 24 in the manner shown.

The'.grip bit block 24 is provided with three pairs of converging guide channels 25 each adapted to slidably receive a grip bit 26 havinga serrated forward end portion 27. The arrangement is such that the pairs of grip bits .26 may be slidably moved within the guide channels25 incooperating fashion to grip the ends or .terminates in a forward collar 36 the forward face of which is adapted to have bearing contact with the rear face of the grip bit 26 associated therewith. The forward collars 36 and the rear faces or surfaces of the grip bits are not rigidly connected but are adapted to contact each other in the manner shown. Surrounding each of the plungers 34 on opposite sides of the crosshead 35 are the coil springs 37 and 38 which extend between the rear faces of the forward collars 36 and the crosshead 35 and between the crosshead 35 and the collars 31, respectively, and are of such a diameter that they will not pass through the apertures within the crosshead.

The above described gripping means is similar to that shown and described in the aforementioned Kerr patent, No. 2,404,234, and it will be observed that forward longitudinal movement of the crosshead 35 along the axes of the plungers 34 forces the plungers to move along their longitudinal axes through drive connections provided by the coil springs 37 and consequently the grip bits 26 move into their operative positions. Rearward longitudinal movement of the cross head causes the gripper bits to retract through drive connections comprisingthe coil springs 38, collars 31 and connecting rods 29 In effect, each of the grip bits 26 is independently and yieldably mounted since a plunger 34, collar 31, coil springs 37 and 38 and connecting rod 29 are provided for each individual grip bit in order that the ends of metal sections are properly gripped regardless of differences in the size and shape thereof.

Rigidly connected to the crosshead 35 adjacent the opposite ends thereof are the forward ends of a pair of identical and generally parallel drive rods 40. Each of the drive rods 40 is accurately guided for longitudinal movement by apertures 41 and 42 provided in the collar mounting portion 32 and forward end portion of the frame, respectively, in the manner shown. The drive rods 40 extend a'lrnpst the entire length of the frame 10 and are further guided for longitudinal movement intermediate their ends by. a pair of integral apertured bosses 43 projecting into therecess 15 from the frame 10 and by a pair of elongated and shouldered spacers 44 carried thereby. The rear end portion of each of the drive rods 40 'is'slidably received within a tubular fitting 45 having a segment of a rack 46 on the upper face'of the forwardend-portion thereof and an enlarged longitudinally extending bore 47 adjacent its rearend of greater diameter than the diameter of the drive rod. The tubular fittings 45 are suitably guided for longitudinal movement'with respect to the frame 10 by properly formed portions thereof as is readily apparent. Received within the bore 47 of each of the tubular fittings 45 is an externally threaded tubular portion 49 of a projecting latch 50 whose use will be hereinafter more fully explained. The threaded'tubular portion'49 of each of the latches 50 is held in rigid relation with "respect to the tubular metal sections protruding from the die block 20. Each of the grip bits has a vertical bore 28 in the upper exposed rear surface thereof which is, adapted .to receive one downturned end of a U-shaped connecting rod29.,i The other end of the U-shaped connecting rod is. received within a vertical bore 30 of a collar 31 that isguided for sliding movement in a properly formed collar mounting portion 32 of the housing. It will be notedthat the collar mounting portion 32 is formedwithslo'ts 33 to provide clearance for'the connecting rods 29and it is preferred, although not shown, that some means. such as j pro ections extending from the collar. guided in' suitable ways, he provided for retaining the collars in proper alignment with the connecting rods. Secured. tofthe forward end of each of the collars 31 is a forwardly pro.-

fitting 45' QSSOClZItEd'IflCICVi/lth by means of a lock nut 51. It will thus be seen that the rear ends of the drive rods are slidably received within the tubular assemblies including the fittings 45'and the latchesflSO while thesefitting 45 associated therewith and disposed on opposite sides of. this shoulder in...encircling relation with the drive rod and within the confines of the tubular bore are spaced coil springs '54 and 55. The shoulders 53 form, fin eif ect, abutments and it will be noted that ifthe, tubular fittingsfand latches'are moved to the left from their retracted positions the drive rods will-also.

be moved to the left under the influence of the coil springs while when the tubular fittings and latches are moved to the right the drive rods are also driven by the coil springs. This provides, in essence, a resilient or yieldable driving connection between the tubular fittings and the crosshead 35 and latches 50 carried by the drive rods. Positioned forwardly of the tubular fittings 45 between these last mentioned members and the spacers 44 in encircling relation with the drive rods 40 are a pair of return coil springs 56 whose function it is to return the tubular'fittings and consequently the drive rods to their retracted positions in a manner to be further explained. The driving means for actuating the gripping means comprises an electric gear motor 58 having a rearwardly extending drive shaft 59 mounted within the recess 15 of the frame directly behind the gripping.means.- Keyed to the drive shaft 59 is a bevel gear 60 which mates with anormally disposed bevelgear 61- mounted intermediate the ends of a transversely extending splined and shouldered shaft 62 whose ends are journaled by bearings 63 in cup shaped bearing carriers 64 rigidly received within the frame 10. Also mounted on the shouldered shaft. 62 adjacent the ends thereof and adapted for rotationv therewith are a pair. of wheel gears 65 havinggear teeth along a portion of their circumferences adapted to nieshwiththe racks 46011 the tubular fittings-45 as clearly shown in Figure 2 of the drawing. It'will thus be seen that upon energization of the electric gear motor 58 the tubular fittings '45 and consequently the drive rods 40 and the crosshead ,35 and latches 50 mounted on the drive rods will be moved in a longitudinaldirection by virtueof the meshing racks 46 and wheel gears 65 .which are interconnected by the above described gearing with the electric gear motor 58. The driving means is so constructed and employed and the drive rods, tubular fittings and latches are so guided that the drive rods will be actuated in exact synchronism and any relative movement between these members is precluded.

One of the important aspects of the present invention is the means employed for energizing the gear motor 58 for actuating the gripping means and moving the latches. This means comprises a suitable electrical connector 66 mounted on and projecting from the forward end of the frame 10. The electrical connector 66 is connected by suitable conduits, not shown, with the gear motor and the forward face thereof is aligned with the forward edge of the'grip bit block. A mating electrical connector, not specifically shown, is mounted-on thedie block 20 and the arrangement 'is suchthat-when" the draw buggy is moved into abutting relation with the die block an electrical circuit is completed due to the engage ment of the two connectors and energizing potential is thus supplied to the gear motor 58 to actuate the same thereby causing movement of thedrive rods and actuation of the gripping means. However, whenthe. draw '6 7 element 69 which spans the recess 15 adjacent the rear ends of the latches 50. ,The hook and back-up ele-' ment are suitably apertured to define a transverse bore,

70.which receives the transversely extending latch rod 71 and it will be noted that appreciable portions 'of the circumferential surface area of the latch rod adjacent the ends thereof and overlying the latches are exposed while the portions between the hook proper and the end portions are completely exposed. Mounted on the latch rod on these last mentioned portions on opposite sides of the hook proper are a'pair of downwardly depending cams 72 whose function it is to cooperate with cam members, not shown, mounted on the bench for raising the hook. The ends "of the latch rod '71; overlie the ends of the latches and when the latches are in their rearmost positions the :hook cannot be lowered because of the latch rod engages and rests upon the upper surfaces of the latches. However, when the latches are moved forwardly va suflicient distance the hook is allowed to drop to engage a link of the drivenchain. The latch rod 71 is retained within its bore 70 byv a pair of endcover plates 74 bolted to the ends of the back-up element 69 and this arrangement is particu-v larly advantageous since itprovides for quick removal andireplacement of the latch rod which will be subjected to constant hammering and shock'forces when the hook is droppedon the latches. It is-notedthat the back-up element provides considerable structural support-pend to withstand hard and continuous usage.

reinforces the latchrod 'to provjde an assembly adapted Operation Considering now the operation offfthe' draw buggy above described, it is assumed that fa drawing operation has been completed and the draw buggy is being re-. turned along the bench toward the die block. At this timethe grip bits 26 are in'their retracted .or inopera tive positions and the hook 18 is in the raised position with the ends of the'latch rod 71 resting'on the upper surfaces of'the rearwardly extended latches whereby thehook is free of the drive chain. The gearmotor 58 I is, of course, de-energized at' this time. It is an ssumed. that metal sections have been loaded in the dies with the pre-pointed ends thereof projecting past the face ofthe die block. j. I

As the draw buggyabuts against the face of the die block the electrical connector 66 engages the connector mounted on the die block thereby completingjan' energizing circuit for the gear motor 58. Energization of the gear motor causes rotation of the shouldered shaft 62 and the Wheel gears 65 carried thereby to .begin'to move I the tubular fittings 45 and the latches '50 in a forward buggy is not in abutting relation with the die block the gear motor is not energized and in this manner, as will Y be further explained, the driving means is positively The hook 18 is formed yvithan integral bess'dit its l rear end and is .pivotally mounted in a rearwardly' extendingmanner for verticalpivotal movementwithinthe recess 15,, by means of a transversely extending pivot pin ,68- s pann ing the recess". Intermediate theboss-and the downturned projection which is adaptedto'engage a link of the continuously drivenuchain, the hook increases in transverse dimension and is provided with a transversely extending and properly formedrigid back-up direction, As the tubular fittings and latches move forward the ends of thelatches engage the rear end of the, coil springs 55 and adriving force is transmitted to the drive rods'40 through these yieldable coil springs acting" against the shoulders 53. As the ,tubularfitti ngs are moved forward thereturn coil sprihgs-Sdfehcircling the .driver ods are compressed and exerta force tendingto move the, tubular members and latches to their retracted positions. g'As the drive rods move forward the crosshead 35 carried directly'thereby is also caused to move latches 501 have not as yet moved forward 'to. such an extent that the hook is free to drop. I loweveryasthe and, through springs 37 and plungers 34,1exerts a force on the various grip bits 26 the sameinwardlyand'firrnly about the projecting pre-poi'nted-ends of .the:me'tal sec? tions. It should be apparent that the entire driving con: nection from the gear. in otor 58 to "the individual grip bits is yieldable'and resilient due to the inclusion" of the" various coil springs and this allows eachofflthe' endsof the metali sections to gripped. With the ends of the metal-sections thusgripped, the;

tubular and latches' continue t'o 'move forward a short distancethereby' further compressing springs be Pr perly and'i'ndependently mit retraction amazes 55 as the ends of the metal sections are now properly gripped'and this exerts a greater gripping force on the ends of the metal sections through the drive rodsthe latches move out from under the latch rod. .The hook 18 now falls to engage a link of the driven chain so that the draw buggy is propelled along the, bench away from the die block. It should be understood that the latches are of such a length and are so designed with respect to theother portions of the draw buggy that they do not move out from under the latch rod unless and until the end portions of the metal sections are properly gripped.

When the hook falls it engages a link of the driven chain and as the chain takes up the load it rises to the elevation of the transversely extending pivot pin 68 thereby lifting the latch rod sufiiciently above the latches to allow for the return movement of the latches. As soon as the draw buggy begins, to move the gear motor 58 is de-energized as the electrical connectors are separated from each other. The grip bits are retained in tight. gripping relation with the ends of the metal sections since the metal sections being pulled through the dies are under considerable tension.

As soon as the gear motor is de-energized and the hook is raised the elongated coil return springs 56 gain controland exert a force sufficient to move the tubular fittings 45 and the latches S to their original positions with the latches preventing downward movement of the hook. It will be noted that the axis of thepivot pin 68 is above the plane of the, upper surfaces of the latches so that the movement of these members does not interfere with the drawing operation. The tubular fittings and latches will be returned to their original positions in a very fast manner under the action of the return coil springs 56 and it may be desirable to provide means for limiting or braking the torque of the motor during latching of the hook. While the tubular fittings and latches are moving to their original positions the compressive forces on the coil springs 55 will be relieved and after sutficient travel the coil springs 54 will act on 'the shoulders 53 to transmit a retractive force on the drive rods 40 thereby causing the same to move in a rearward direction. The crosshead 35, which is rigidly connected to the ends of the drive rods, will also move in the same direction and this movement is sufiicient to relieve the coil springs 37 and to compress the coil springs 38 whereby the grip bits are urged to their retracted or inoperative positions through the collars 31 and U-shapedconnecting rods 29. Of course, the tension exerted by the metal sections being drawn is much greater than that applied by the coil springs 38 so that the grip bits remain in tight gripping relation with respect to the ends of the metal sections. It is noted that the yieldable and resilient connections provided by the various coil springs employed throughout the draw buggy insure that the actual drawing operation will be completed in a continuous and uninterrupted manner.

To provide means to raise the hook 18 during move-, ment ,of the draw buggy irrespective of the load and tightness of the driven chain the pair of cam members are positioned along the tracks and are adapted to be engaged by the depending earns 72. If the hook is down when the cam members are reached. the lower surfaces of the cams ride up the inclined upper surfaces of the cam members thereby raising the hook sufficiently to perof the tubular fittings, latches and drive rods. r v

v.As themetal sections leave the diesthe tension on the properly shaped and/ or formed metal sections and the grip bits will be immediately released in a sudden manner and .strike the upper surfacesof the latches th'ereby retaining the hook in its original raised position. The draw buggy is thus conditioned for another drawing operation with the latches, tubular fittings, hook, drive rods and grip bits in their retracted positions and these elements will remain in these positions until the gear motor 58 is again energized. After unloading of the drawn metal sections the draw buggy may be returned to a position adjacent the die block for another drawing cycle.

In considering the above described operation of the draw buggy of the present invention it should be apparent that the same provides many advantages. Of particular importance is the use of the various coil springs which not only insure proper gripping action by providing yieldable and resilient driving connections but also provide shock absorbing means for dissipating the shock forces attendant to drawing apparatus upon the metal sections leaving the dies, etc. The gear motor and the gearing provides an excellentmeans for actuating the gripping bits wherein the ends of the metal sections are firmly and positively gripped prior to movement of the draw buggy. The means for energizing the driving means, although extremely simple, is advantageous since the driving means is energized only as required while yet insuring the proper gripping of the metal sections. The hook and latching arrangements therefor are well adapted for drawing operations and the concept of a latching means operative in response to closure of the grip bits a short time after the ends of the metal sections are gripped is especially important.

Gripping means In Figures 4-6 of the drawing there is shown an improved gripping means for a draw buggy constructed in accordance with the teachings of the present invention. The draw buggy embodied in these views of the drawing is, with the exception of the gripping means, the same as that described above and in order to eliminate unnecessary repetition in the specification like parts are designated by the same reference numerals.

' Mounted for sliding movement within each of the guide channels 25 of the grip bit block 24 is a grip bit holder that carries on the'forward face thereof, by means of a dovetailed channel, a grip bit element 81 having a serrated face portion 82. The grip bit holder has a vertical through bore 83 in the exposed rear end thereof which serves as a retaining socket for a generally cylindrical pivot block 84. A snap ring 85 is used to close the bottom ofthe through bore 83 and to retain the pivot block 84 within the thus defined socket. The extreme rear end portion of the grip bit holder 80 has a vertically extending slot 86 which communicates with the vertical through bore and exposes the pivot block from the rear. In. addition to the vertical slot the rear end portion of the grip bit holder and the exposed portion of the pivot block are formed or machined to define a frustro-conical bore 87 whose use will be hereinafter more fully apparent.

' Extending longitudinally with respect to the frame of the draw buggy is an actuating rod 88, the forward end portion of which is 'threadably attached and pinned to the pivot block 84. The actuating rod extends axially Within the above defined frustro-conical 'bore 87 and'is slidable within a second generally cylindrical pivot block 89 intermediate its'ends. The second 'pivot block 89 is received within a cup-shaped holder 90 having a vertically extending slot 91 therein to defineopenings on its opposite sides- The cup-shaped holder 90 and the second pivot block 89 are each machined or formed to provide a pair of frus'tro-conical longitudinally extending openings 92 on oppositesides thereof adjacent the vertically ex- .tending slot to provide clearance for the movement of the actuating rod 88.

The rear end portion of the actuating rod 88 is threaded and mounts a retaining nut 93. Also provided in en circling relatio'n with respect to the actuating rod 88 are a pairof compression coil springs 94 and 95--the first of these springs extending from the pivot block 84 to the pivot block 89 and the second of these members being positioned between the pivot block 89 and the retaining nut 93.

As is readily apparentifrom the drawing, the draw buggy comprises three pairs of grip bit holders and elements and each of these members are provided with actuating meansincluding the pivot blocks, cup-shaped holders, actuating rods, retaining nuts, compression coil springs, etc.--as described above. In this manner of providing separate actuating means for each of the grip bit holders and elements it is insured that all of the prepointed ends of the metal sections will all be properly gripped prior to movement of the draw buggy thereby greatly facilitating the drawing operation.

The plurality of cup-shaped retaining members 90 are mounted in aligned fashion on a movable and transversely extending crosshead 97 which is an angle member and has a plurality of properly positioned apertures 98in the upstanding wall thereof to permit the unobstructed passage of the plurality of actuating rods 88 therethrough. The crosshead 97 is rigidly mounted on the forward ends of the drive rods 40 and, of course, is movable with these members.

In the operation of the gripping means the draw buggy is returned to the die block and the gear motor 58, is energized to move the drive rods forward in the manner heretofore described. Movement of the drive rods causes the crosshead 97 to be carried forward-the actuating rods 88 are slidably received within the pivot blocks 89- thereby exerting a force through the coil springs 94 against the pivot blocks 89. This causes the grip bit holders 80 to slidably move'within their guide channels and the grip bit elements forcibly and positively engage the protruding prepointed ends of the metal sections. The position of the various apparatus when the crosshead is in its most forward position is shown in Figure 4 of the drawing.

Probably the most important advantage of the gripping means is the elimination of a substantial amount of sliding friction. It will be observed that in the gripping means described in connection with Figures 1 and 2 of the drawing that the cooperating pairs of grip bits 25 move in a converging manner while the plungers 34 and collars 31 and 36 are guidedfor and limited to longitudinal movement and because of these angularly related directions of guidance and movement there must be relative movement in a transverse plane between the rear ends of the grip bits and the forward faces of'the collars 36. This relative movement results insubstantial sliding friction in the transverse plane since these,

members are under pressure in the longitudinal direction and this problem is most acute at the exact moment the grip bits engage the ends of themetal sections. The sliding friction resulting from this relative movementis considerable and may prevent the proper gripping of the ends of the metal sections thereby causing a'serious delay if one or more of the metal sections is notdnitially gripped or the draw is interrupted by release of one or more of the metal sections.

In the present gripping means, however, such sliding friction in the transverse direction is entirely eliminated since as the grip bit elements 81Imove inwardlyi the actuating rods 88 will pivot or swing as needed in a free and easy manner due to the pivotal connections be tween the grip bit holders, the cross-head and the actuating rods. Each of the pivot. blocks is freely pivotable about its vertical axis and the .frustro-conical bores are of .s'uch size and shap'eto'permit swinging movement of the interference between adjacent actuating rods. In essence, the gripping means is characterized by its complete lack of sliding friction in. the transverse direction and proper and positive gripping of the ends of the metal section is always insured.

A short time after the ends of the metal sections are properly gripped the hookof the draw buggy is dropped to engage a link of the driven chain and'the draw buggy moves away from the die block thereby de-energizing the gear motor 58. The previously compressed return coil springs 56 gain control and drive the drive rods 40 and the crosshead 97 to the rear thereby relieving the coil springs 94 and compressing the coil springs 95 which exert forces tending to retract the grip bit elements to their inoperative positions. The metal sections are under considerable tension during drawing and this precludes retraction of the grip belt elements during drawing opits simplicity of construction but yet is operable in an improved manner. One important aspect thereof is the extreme case with which the gripping means may be removed and replaced. The pivot blocks 84 and 89, springs 94 and 95, retaining nut 93 and actuating rod 88 form a self-contained assembly for each of the grip bit elements which may be lifted directly from the draw buggy due to the provision of the various vertically extending slots 86, 91 and 98 in the grip bit holders, cup-shaped holders and crosshead, respectively. i

Although I have accomplished the objects initially set forth, it should be apparent that many changes may be made in the illustrated embodiments of the invention without departing from the teaching thereof. Accordingly reference should be had to the following appended claims in determining the true scope and intent of the invention.

I claim:

1. In a drawcarriage for metal drawing equipment hav-v ing an elongated frame and at least one pair of converging grip bits carried by one end of said frame and guided for movement in converging directions whereby the bits may be moved into and out of engagement with a work piece the improvement comprising a pair of transversely pinion gears keyed thereon and meshing with said rack gears, an electric motor mounted on said frame between.

, saidrods, reduction gearing between the 'output sh'aftof 2 the motor andsaid transverse shaft, and a-plug-in type of y electrical connection rigidly carried by said frame adjacent said grip bits and adapted to engage a connection on said carriage whereby current is supplied to the'motor when said carriage isat the die block of said equipment.

2. Apparatus according to claim 1 further including energy storage means to automatically move said rods and rack and pinion gears and reduction gearing back to their initial starting positions upon de-energization of said motor when said carriage moves away from said die block. 1 '3. Apparatus according to claim 1 wherein a pivoted draw-chain hook and a latchto holdthe sameYintupper chain-free position is located'on the opposite end of said frame from said grip bits the further improvement of I providing a longitudinally elongated latch and actuating. Q linkage between said latch'and said rack gears whereby.

fs'aid latch is released onlyupon said rods'being advanced a predetermined distance in grip-bit closing direction by 1,574,381 .Entenmann Feb. 23, 1926 said motor. 1,951,073 Wallis Mar. 13, 1934 2,404,234 Kerr July 16, 1946 References Cited in the file of this patent 2 535 9 1 Schiller Aug. 10, 5 UNITED STATES PATENTS 5 2,845,171 Heym July 29, 1958 672,914 Quimby Apr. 30, 1901 FOREIGN PATENTS 715,862 Qulmby 16, 1902 451,481 Great Britain Aug. 6, 1935 868,375 TWer 15, 1907 595,470 1 Great Britain Dec. 5, 1947

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