US2685961A

US2685961A - Appabatus fob drawing stock

Info

Publication number: US2685961A
Authority: US
Publication date: 1954-08-10
Anticipated expiration: 1971-08-10

Description

Aug. 10, 1954 o. R. SCHULER APPARATUS FOR DRAWING STOCK 4 Sheets-Sheet 1 Filed Jan. 8 1951 INVENTOR. 07 70 SC'f/Ulfk BY W M ATTORNEYS Filed Jan. 8, 1951 o. R. SCHULER APPARATUS FOR DRAWING s'rocx 4 Sheets-Sheet 2 IN VEN TOR.

oz-ro R. SCI/045R Aug. 10, 1954 o. R. SCHULER APPARATUS FOR DRAWING STOCK 4 Sheets-Sheet 3 Filed Jan. 8, 1951 IN V EN TOR.

03-70 A sax/()4 8 BY I X MM

Aug. 10, 1954 o. R. SCHULER 2,685,961

APPARATUS FOR DRAWING STOCK Filed Jan. 8, 1951 4 Sheets-Sheet 4 .3 R m P M E z 0 Wm M a v I m w A um mm 2 Patented Aug. 10, 1954 APPARATUS FOR DRAWING STOCK -tto R. Schulen'Detroit, Mich., assignor to Calumet & Hccla, Inc., a corporation of Michigan Application January 8, 1951, Serial No. 204,920

4 Claims.

This invention relates generally to apparatus for drawing lengths of stock through a die.

In drawing stock of substantial length, it is customary to employ a draw bench having a die and having a carriage movable relative to the die in directions toward and away from the die. The leading end of the length of stock is ordinarily releasably secured to the carriage by gripping jaws, so that movement of the carriage in a direction away from the die pulls the stock through the die.

The jaws are usually constructed to grip the stock with a force proportional to the pull applied to the stock, and to automatically release the stock upon forward displacement of the stock relative to the carriage. In this connection it is to be noted that the stock is placed under considerable stress during the drawing operation, and the resulting energy is released as soon as the trailing end of the length of stock leaves the die. This energy snaps the length of stock forwardly relative to the carriage and releases the jaws from the leading end of the stock.

In practice the lengths of stock virtually jump forward at a rate considerably higher than the forward rate of travel of the carriage, and in so doing, the leading end of the stock jams against some part of the carriage. As a result the length of stock buckles or kinks to such an extent that it is frequently necessary to cut off the kinked end of the stock and scrap the same.

With the above in view, it is an object of this invention to eliminate any possibility of deforming the leading end portion of the stock as the trailing end is disengaged from the die by providing means on the carriage in the form of a shock absorber for dissipating the energy stored up in the stock during the drawing operation. In accordance with this invention, movement of the stock forwardly relative to the carriage by the energy built up during the drawing operation is permitted at a rate so controlled that kinking or buckling of the length of stock is avoided.

The foregoing as well as other objects will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings, wherein:

Figure 1 is a side elevational view partly in section of a portion of a drawbench embodying the features of this invention;

Figure 2 is a cross sectional view taken on the plane indicated by the line 2-2 of Figure 1;

Figure 3 is a fragmentary sectional view taken on the line 3-3 of Figure 1 showing the clamping jaws closed;

Figure 4 is a side elevational view partly in section of a modified construction;

Figure 5 is a side elevational view partly in section of another embodiment of this invention;

Figure 6 is a fragmentary sectional view taken on the line 66 of Figure 5;

Figure 7 is a side elevational view partly in section of a further modification of this invention;

Figure 8 is a sectional view taken on the line 8-8 of Figure 7;

Figure 9 is a side elevational view partly in section of a further embodiment of this invention;

Figure 10 is a sectional view taken on the line iii-Iii of Figure 9;

Figure 11 is a cross sectional view taken on the line ll-H of Figure 10;

Figure 12 is a fragmentary sectional view of still another embodiment of the invention; and

Figure 13 is an end elevational view of the construction shown in Figure 12. 7

Referring first to the embodiment of the inventioh shown in Figures 1 to 3 inclusive of the drawings, it will be noted that the numeral [0 indicates a die having an opening H through which a length of stock i2 is drawn by a carriage 13. The nature of the stock I2 is not critical, insofar as this invention is concerned; and may be either in the form of a rod or a tube. Also the carriage l3 may be of any suitable construction or type, depending on the character of the drawbench employed. For the purpose of illustrating the present invention, the carriage I3 is of the type which is moved in a direction away from the die is by a chain diagrammatically indicated by the numeral l4, and is returned to its starting position adjacent the die I0 by any suitable means not shown herein.

Briefly the carriage I3 comprises a frame and wheels :5 suitably supported on the frame in positions to engage laterally spaced tracks I! mounted on the bed of a machine frame structure not shown herein. In accordance with conventional practice the carriage I3 is releasably connected to the chain 54 by a dog l8 pivoted intermediate the ends thereof on the carriage frame l5 by a pin 5 5 having its axis extending horizontally to enable vertical swinging movement of the dog relative to the chain. The front end of the dog I8 is fashioned with a hook 29 adapted for engagement with one of the transverse pins of the chain, and has a weight exceeding the weight of the rear end 2! of the dog, so that the hook is normally urged by gravity into engagement with the chain M.

In the interests of simplicity the usual mechanism 22 is provided for releasably holding the dog I8 in its inoperative or uppermost position with respect to the chain. In general this mechanism comprises a link pivotally supported intermedia'te the ends thereof on the carriage frame I by a pin 24 having its axis ext-ending parallel to the pin I9. As shown in Figure l of the drawings, the lower end of the link 23 has a roller 25 positionedto engage a cam face 25 formed on the rear end 2| of the dog 18. The upper end of the link 23 is pivoted to the front end of a rod 21 which is slidably supported on the carriage by :5 lug 28 projecting upwardly from the carriage frame I5. A stop collar 29 is suitably secured on the rod 21 at the rear side of the lug 28, and a coil spring 30 surrounds the rod '27 between the lug 28 and collar 29. The construction is such that the spring 30 normally urges the link 23 about the pivot pin 24 in a direction to engage the roller 25 at the lower end of the link 23 with the cam surface .26 on the rear end of thedog I8. Thus the dog [8 isnormally held in its released posit-ionindicated bythe broken lines in Figure 1 of the drawings.

It will also be noted from Figure 1 of the drawings that an abutment-3| is secured to the rear end of the rod 21 in a position to contact the front side of the die ID or its support when the carriage I3 is retracted to its starting position immediately adjacent the die [0. Engagement of the abutment with the front face of the die or some other suitable support swings the link 23 out of. engagement with the cam 28 on the rear end of the dog [8 and permits the front end of the dog to swing downwardly to a position wherein the hook engages the front side of an adjacent ,pivot pin on the chain I4. Asa result the "carriage l3 is'moved in'a direction away fromthe die MI by the chain I4.

Also in accordance with orthodox practice the leading "end of the stock I2 is releasably secured tothe rear end of the carriage l3 by a clamp 32 so that forward movement of the carriage 13 by the chain I4 draws the length of stock I2 through the'opening II in the die I0. As shown in Fig- .ure 3 of the drawings, the clamp 32 comprises a supporting block 33 and a pair of jaws 34. The supporting block 33- is-movable as a unit with the carriage I3, and is provided with a pair of grooves 35 in the top surface for respectively slidably receiving the jaws 34. The grooves '35, and, accordinglythe jaws 34, diverge'toward the die [0 in a manner such that rearward movement of the jaws 34 in the respective grooves 35 wedges the adjacent serratedfaces of the jaws into grip- :ping relationship with the leading end of the stock which has previousl been projected through the die opening I I. Also with this construction itwill be apparent that the gripping action of the jaws 34 on the stock increases in proportion to the load or the pull applied to the stock by forward movement of the carriage l3.

is usually the case the jaws 34 are moved into gripping relationship with the leading end of the length of stock ['2 by a lever 36 pivoted. intermediate the ends thereof on a pin 31. The pin 3'! is supported on a part 38 carried by the carriage I3, and to be more fully hereinafter described. The axis of the pin 3'! extends in a direction to enablev swinging movement of the lever 36 in a vertical plane, and the lower end of the lever .36 has "a part 39 positioned adjacent the front ends of the gripping jaws 34.

The'upper end of thelever 35 is located betweena pair of abutments 40 and :4I slidably 4 mounted on a rod 42. The rod 42 is suitably mounted on the part 38 for sliding movement in the direction of movement of the carriage I3. In the present instance the part 38 has upstanding projections 43 spaced from each other axially of the rod '42 and having aligned openings therethrough for slidably receiving the rod 42. The abutments 40 and 4| are located between the projections 43 and are normally urged against sliding movement relative to the rod 42 by springs 44. The springs 44 are respectively mounted on therod 42 between the projections 43 and the abutments 40 and 4|. The rear end of the rod 42 has a head 45 positioned to engage the front face ofthe die ID or some other support when the carriage approaches its initial starting position adjacent the die i0. As a result the rod 42 is shifted forwardly, and the lever 36 is moved about the pin 31 in a direction to shift the jaws 34 rearwardly into gripping relationship with the leading end of the length of stock. Thus when the dog. I8 on the carriage is released to engage the chain .I 4 and the carriage is thereby advanced, the length of stock 12 is pulled through the die .10 by the action of the gripping jaws 34.

It will .be understood that with drawbenches of the type-briefly described above, the gripping jaws 34 are automatically released from the leading end of the length of stock I2 at the time the trailing end of the stock leaves the die Ill. The automatic release of the gripping jaws 34 is effected by the energy stored in the stock during the drawing operation. Upon completion of the drawing operation or in other words when the .trailing end of the stock leaves the die I0, the stored up energy is released, and the length of stock I2is displaced in a forward direction at a substantial rate. In fact the stock actually jumps c forwardly relative to the carriage, and the thrust imparted to the jaws 34 is sufficient to release these jaws from the stock. .It may be pointed out at this time that such a release of the jaws from thestock, is permitted by the jaw operating lever 36 due to the action of the springs 44. Since the trailing end of the stock is out of contact with the die I0 when the jaws 34 are released, the length of stock 12 is free to drop from the drawbench.

When, the stress applied to the stock during thedrawing operation is released, and the stock jumps forwardly, it frequently travels ata rate considerably higher than the rate of advancement of the carriag l3; and as a result, jams against apart of the carriage. This condition usually causes buckling or kinking of a portion .of th leading end of the length of stock l2, and insome instances, necessitates scrapping a substantial length of the leading end of the stock before subsequent operations may be satisfactorily accomplished. This serious objection and accompanying waste of material is overcome in the present instance by embodying a shock absorber 50 for dissipating the released energy stored up in the stock during the drawing operation, and for retarding movement of th stock relative to the carriage I3.

Upon reference to Figure 1 of the drawings, it will be noted that the shock absorber 50 is supported on the part 33 previously described as carrying the gripping jaws 34 and associated actuating mechanism. The part 38 is suitably fastened to the rear end of the carriage l3 to form an extension of the latter, and if desired, additional wheels 51 may be provided on the extension ,for supporting the same on .the tracks IT. Thus the part 38 actually may be formed integral with the carriage or may be attached to existing carriages of drawbenches.

In any case the shock absorber 53 comprises a tube 52 and a plunger 53. The tube 52 is mounted on the part 38 above the center line of the drawing operation with its axis extending in the direction of movement of the carriage I3. The rear end of the tube is open and is positioned forwardly of the gripping jaws 34 to receive the leading end of the stock I2 after the latter is released from the gripping jaws 34. As shown in Figure 1 of the drawings, the jaw supporting block 33 has a part 54 located between the front ends of the jaws and inclined to direct the leading end of the stock upwardly toward the open rear end of the tube 52. If desired the part 38 may also have a guide section 55 formed thereon to assist the part 54 in guiding the leading end of the stock I2 into the open rear end of the tube 52.

The plunger 53 is slidably supported in the tube 52 and is normally urged to a position adjacent the rear end of the tube by a coil spring 56 located within the tube 52. The front end of the coil spring abuts the part 33, and the rear end of the coil spring engages the plunger 53 which is recessed at the front side to receive the adjacent end of th coil spring 55. A recess 57 is also formed in the rear side of the plunger 53, and this recess is adapted to receive the leadingend of the length of stock I2 as the latter is moved forwardly relative to the carriage I3.

It follows from the above that when the length of stock I2 is suddenly displaced in a forward direction relative to the carriage I3, it is guided into engagement with the plunger 53 in the tube 52. Forward sliding movement of the plunger 53 relative to the tub 52 is resisted by the spring 56, and the strength of the latter is determined to gradually retard movement of the stock with a progressively increasing force. Thus the tendency for the stock to kink or buckle is reduced to a minimum, and subsequent straightening or cutting operations on the stock are avoided. It will be understood that continued forward ad vancement of the carriage after releasing the leading end of the stock I2 is usually sufiicient to provide for withdrawing the length of stock from the tube 52 of the shock absorber.

The modification shown in Figure 4 of the drawings differs from the foregoing construc tion in that the shock absorber 53 is supported above the carriage I3 instead of at the rear end of the latter. This construction may be desirable under some conditions, because it oifers the possibility of reducing the overall length of the carriage I3. With the above exception, the construction shown in Figur 4 is the same as the one previously described; and corresponding parts are indicated by the same reference numerals.

The embodiment shown in Figures 5 and 6 of the drawings differs primarily from the construction shown in Figures 1 to 3 inclusive in that the shock absorber 69 is supported at the underside of the extension or part 38 of the carriage I3. As shown in Figure 5 the shock absorber 63 comprises a length of tube 6i secured to the underside of the part 38 with its axis extending in the direction of movement of the carriage 13. A plunger 62 is slidably supported in the tube 6|, and is normally urged to a position at the rear end of the tube by a coil spring 58 supported within the tube 6I.

In the present instance the length of stock I2 is directed downwardly from the gripping jaws 34 into the rear end of the length of tube SI; and in order to accomplish this result, th part 54 of the jaw supporting block has the underside thereof tapered in a downward direction as shown in Figure 5. Also the part 38 has a guide 63 which in effect forms a continuation of the tapered surface on the part 54 and extends forwardly to the rear end of the tube 6I. As shown in Figure 5, the plunger 62 has a projection 64 which extends axially through the rear end of the tube for engagement with the stock to guide the same into proper engagement with the plunger.

It will further b noted from Figure 5 that the rear end portion of the tube 6I has a slot 65 in the bottom thereof, and the purpose of this slot is to provide clearance for passage of the stock in'a downward direction out of the tube 6I. The construction is such that after the energy built up in the stock during the drawing operation is dissipated by the spring 68, the stock may drop by gravity through the slot 65 in the length of tube 6|.

In the embodiment of the invention shown in Figures 7 and 8 of the drawings, the forward displacement of the length of stock I2 is damped without deflecting the stock laterally from its normal drawing position. In detail the gripping jaws 34 for the length of stock I2 are slidably supported on a slide 66 which in turn is slidably mounted on the extension or part 38 for movement relative to the carriage I3 in the direction of advancement of the latter. The slide 66 is normally held in engagement with a stop 51 at the rear end of the part 38 by a coil spring 68. The front end of the coil spring 68 abuts a fixed portion of the part 38 and the rear end of the coil spring'abuts the slide 66 in the manner clearly shown in Figure '7 of the drawings. It will also be noted that the line of action of the spring 68 is substantially in alignment with the center line of the pull applied to the length of stock during the drawing operation.

As shown in Figure 8 of the drawings, the gripping jaws 34 are guided by a generally wedgeshaped part 10 fixed to the slide 66 between the jaws. The construction is such that when the laws 34 are released from the stock I2 as a result of disengagement of the stock from the die III, the stock I2 imparts a forward thrust on the part III and moves the slide 66 in a forward direction against the action of the spring 63. Thus movement of the stock I2 relative to the carriage I3 is damped by the spring 68. The remaining parts of the embodiment shown in Figures 7 and 8 may be identical to the construction defined in Figures 1 to 3 inclusive, and corresponding parts are indicated by the same reference numerals.

The embodiment of the invention shown in Figures 9 to 11 differs from the construction previously described in connection with Figures 7 and 8 in that the shock absorber II comprises a length of tubing '52 and a plunger '13 slidably supported in the tube I2. The length of tubing '12 is secured to the part 38 of the carriage I3 directly to the rear of the gripping jaws 34, and the rear end of the tube I2 is open to receive the leading end of the length of stock I2 upon release of the stock by the gripping jaws 34.

The plunger 33 is shown in Figure 10 of the drawings as having a rearwardly extending projection I4 which is of sufficient length to extend through the open rear end of the tube I2 between the front ends of the gripping jaws 34. The arrangement is such that when the leading endlof. thestock I2 is released bythe jaws-,the stock engages the projection 14 and moves. the plunger 13 ina forward direction relative to the tube 12. Movement of the plunger [3 by the length of stock I2 is resisted by a coil spring 15 housed. in the tube 72 and being of suificient strength to damp forward movement of the stock relative to the carriage. V

p The embodiment of the invention shown in Figures 12 and 13 illustrates an alternate plunger 1:! which may be used in the construction shown in Figures 9 and 10 of the drawings. In detail the plunger 11 has a rearwardly extending projection l8 fashioned with a recess 79 in the rear end thereof. The bottom wall 80- of the recess 19 is inclined in an upward direction and serves to the serrated gripping portions 82 to provide ample-clearance for the stockwhen the latter is released from the gripping portions 82. Also the jaws have forwardly extending rails 83 at the topand bottom of the respective jaws; These rails 83' slidably engage in suitable recesses in the supporting block 33 to guide the jaws 34", and the front ends of the rails 83 are positioned for engagement with the jaw operator 36. With the above exceptions the construction may be the same as the one described in connection with Figure 9.

It will be noted that all of the embodiments of the invention selected herein for the purpose of illustration disclose a carriage or equivalent pulling device having means in association therewith for retarding or damping the sudden forward displacement of the stock relative to the carriage resulting from releasing the stock from both the die and gripping jaws. Thus severe buckling o-r kinking of the stock heretofore experienced in conventional drawbench constructions is overcome, and the drawing operation is improved generally. I

What I claim as my invention is:

1. In apparatus for drawing lengths of stock, a; die having an opening therethrough for receiving a length of stock, a device movable in a direction away from the die, a releasable clamp carried by the device and having means for gripping the leading end of a length of stock pro- J'ecting through the die to pull the stock through the die upon movement of thedevice in a direction away from said die, said clamp being releasable from the stock by the sudden forward displacement of the stock relative to the device caused by disengagement of the stock from the die, a shock absorbing unit for yieldably and gradually resisting displacement of the stock released by said clamp, said unit being supported on the device and having a part movable relative i the length of released stock comprisinga spring supported in the tube and engagcable with said part.

2. The apparatus defined in claim 1 wherein said tube is supported on the device below. the elevation of the clamp and wherein the bottom of the tube is slotted to release the length of stock.

3. In apparatus for drawing lengths of stock, a die having an opening therethrough, means for drawing a length of stock through the; die opening including a device movable in a direction away from said die, clamping structure including a gripper head mounted on said device, said gripper head supporting gripper means; in the form of cooperating jaws for gripping the leading end of the stool; to pull the stock through the die upon movement of said device in a direction away from said die, said jaws being releasable from the stock by the sudden forward dis:- placement of the stock relative to said device caused by disengagement of the stock from said die, a shock absorbing unit independent of; said gripper head for resiliently resisting displacement of the stock released by said jaws, said unit being mounted on said device and having a part-movable relative to said device in the direction of displacement of the stock released by said jaws, said part being positioned to be engaged by the leading end of the stock released bysaid jaws, an elongated tube slidably supporting said part, said tube extending in the direction of movement of said part and being mounted'on'said device in laterally offset relation to the center line of draw of said jaws, said gripper head having a guiding surface for directing the leading end of the stock into engagement with said part, and resilient means carriedby said device and engageable with said part for resisting movement of the latter relative to said device by the released stock.

4. The apparatus defined in claim 3, wherein said part has a recess for receiving the leading end of the stock released by said jaws, said recess having inclined walls flaring outwardly thereof for guiding the leading end of'the'stock into said recess.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,003,645 Dalton June 4, 1935 2,275,573 Sturm et'al Mar; 10, 1942 2,391,908 Knudsen et a1. Jan. 1, 19.46 2,551,260 Garwig May 1, 1951 2,554,998 Mcllvried et al. May 29; 1951