US2633233A

US2633233A - Drawing machine

Info

Publication number: US2633233A
Application number: US772945A
Authority: US
Inventors: Lee R Berkebil
Original assignee: National Steel Corp
Current assignee: National Steel Corp
Priority date: 1947-09-09
Filing date: 1947-09-09
Publication date: 1953-03-31
Anticipated expiration: 1970-03-31

Description

March 3l, 1953 l.. R. BERKEBIL DRAWING MACHINE 2 SHEETS--SHEET l R Ilo n o`. .w .A Q t m 5 7 Filed Sept. 9, 1947 Tn i b mx QNR IN V EN TOR. ff R. BER/(EBM.

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Vl B 3 2 m mw. 3 E m H o 2 www@ m... W m M E uw m m w B4 G l R. M Q` J Qs il# m L m S y \1 v/ mw. Jmvl//MM #lll/IIIA: M m0 \m 4 l uw A 9 fw/.vvd m V v/ u m, t u. h m m w W M m L w Patented Mar. 31, 1953 DRAWING MACHINE Lee." R'.. Berkebil, Detroit, Mich., assgnorl toi Na.-

tionalA Steel: Corporation, a corporationof. Delai` Ware.

pnlicatioxr September 9, 194'?, Serial No. '772;9'45

'l Claims.

The present invention relates toa@ method of and apparatus for drawingrods` inv which.` lengths of Wires, rods, bars, or the like, hereinafter collectively referred to as 'rods,l are drawnthrough a die toireduce or form the rods tothe desired: size" or shape.

As used herein, they terms ndrawn, drawing and the like are used to indicate that as the rod is moved through the die thevl rod is reduced inA size or formed to the desired shape. These terms are not limited to Where the rod is pulled through the die and include those methods and machines where the rod is pushed through the die while being drawn. i

In some rod drawing machines, the leading end is pointed or is formed in. a reduced size so that' it can be freely pushed through the die. The present invention is only concerned? Withwherethe rod isdrawn, that is, reduced in size or formed to the desired size or shape, upon beingy pushed through the die.. For various reasons, the for-- ward or leading end portion of a rod upon being pushed through the die will at times bend later ally away from the wire lineof' the machine; The bending of the rodsmay be causedhbyimperfections in theV die or mayv be' causedy by variations or imperfections` in the different rods.. or thev bending may result from the combination of these factors. Where imperfections inH the die cause the rods to bend when pushed through the' die,v theL rodsl will bend in the same direction. Bent rods; may notv be properly drawn and may cause damage tothe machine and it usually isl necessary t'o'd'iscard` or reprocess these bent rodswhich is uneconomical. As a practical matter, it is veryf dimc'ult, if not impossible, to construct dies so perfectly that they rodsV do not bend a. slightr amount and a slight amount of' bending which is not sufiicient toI interfere With` subsequent opera-` tionsusually requires that thel rods bei straight-l cned.

-i's 'anobfject ofi the present. invention to providsa method of and apparatus for drawing rods that will reduce or prevent the. rods from bending out of shape. i

' Another object ofv thepresent invention is to provide a methodof and apparatus for drawing rods which theend portionsof those rods- Whichbend or tend to bend upon being pushed through the die as aresult of imperfections in the diew-ill be straightened', either substantially or perfectly, as the rods are pushed through. the die.

A further' object of the` present invention is to provide a metho'dvofi and apparatus for drawing;

tendto bend and that will not deform those. rods which do not tend1 to bend.

Itis also. an objectof thei present invention to provide' a rodi drawing machine including rod; straightening means that is automatically properly positioned.

In accordance vvith` the present invention, a, rod ispushed through the die and. if the rod bends as a` result of4 imperfections in the die,. itiI is straightened as the rod. is advanced through the die. In a rod drawing machine embodying the. principles' of the present invention, a die positioned so that those rods tending toV bendr as aresult of die imperfections,V which may' be all. oru part of the rods being. drawn, will tend. to bend inthe same predetermined direction.. A rodv straightening devicev is provided on` the' exit side. of the die. and this devicev includes a guide which engages the rod and bends it` substantially straight as the end portion is being; pushed. through the. die by thev push carriage. l5?referablyf,l the rod'straightening.` guide is; sot positioned as to bend the end portion of. the rod'` a slight amount beyond the straight condition. so that the stresses: setz up in the rod bythe die will be entirely overcome.l It'. is. neces'- sary to bend the" rod. only slightly beyond the straight condition as. the: stressesV and strains caused. by the die. are readily overcome and. the:` rod at this time has: only a relatively small amount of "springbaclr. If the rod were not straightened until later when the metalhasage hardened, it would bei very' difficult toA straighten the rod and it Would benecessaryto use relatively quite heavy equipment. With the guide posi-v tioned-either to bend and-` maintain the rod sub-- stantially or perfectly straight as it leaves the die or positioned to bend the end portion laterally and slightly beyond the straight condition', the end portion of the rod is bent by the guide in a direction opposite to the direction` the die bends" the rod. to straighten. the rod. Ciani means may be provided to automatically move the guide into and out` of the rod straighteningr position. By

. means of. the present invention, the. production.

ofY the. bent rods as ay result of imperfect dies is substantially or completelyl eliminated.. The rod'. straightening guide does not bend straight rods suiiiciently to deformthem.

I'Ihese and other objects andadvantages of the present invention will become more readily `ap parent from' the following detailed description, taken in connection thek accompanying drawihgsfin-Whichz' reds 'thaise-wm. straight-en out tnosercds which 551 Figur 1 is a pian View! of rod drawing inabox 38 to the hydraulic motor 3|.

chine embodying the principles of the present invention;

Figure 2 is a side elevational view of the machine of Figure 1 with portions of the supporting structure removed;

Figure 3 is an enlarged, fragmentary longitudinal sectional view of part of the machine of Figure 2; and,' l

Figure 4 is an enlarged, fragmentary view taken substantially along line 4--4 of Figure 3.

Referring to the drawings, the rod drawing machine includes a draw bench I on which is mounted in a fixed position a die holder 8. A power-actuated push carriage `9 is slidably mounted in ways I for movement forwardly and rearwardly along bench I toward and away from the die holder. Carriage 9 advances the leading end portion of a rod 24 through a die Ii removably retained in holder 8 by plate I3 upon each forward stroke toward the die I I. A poweractuated pull carriage I2 is supported on bench 'I for forward and rearward movement away from and toward the die holder 8 to pull a rod through die II upon each forward stroke away from die holder 8. Thus, as willbe more fully hereinafter described in detail, the push carriage 9 pushes the leading end of a rod 24 through die II and then pull carriage I2 engages the leading end of the rod and pulls it the rest of the way through the die. The rod is drawn by the die both when it is being pushed and when it is being pulled through the die.

The present rod drawing machine is constructed and arranged for drawing three rods simultaneously. There are three identical dies in holder 8 and three identical rod gripping mechanisms in each carriage. Those mechanisms cooperating to draw one rod will be described in detail, it being understood that these mechanisms are duplicated for each rod simultaneously drawn Aand that it is immaterial whether one or a plurality of rods are drawn.

Carriage 9 Vis connected to the outer ends of pistons Il of a pair of hydraulic cylinders I8 connected throughsuitable .valves (not shown) to a source of fluid under pressure. A` jaw holder I5 is removably mounted.` in a pocket I6 of carriage 9. As shown more clearly in Figure 3, in the-holder I 5; there are -a pair ofgblocks `I I havingtapered,-opposed inner surfaces. A pair of rod-gripping jaws I8 are movably mounted in blocks II with ball bearings I9 disposed therebetween. Springs 2I urge the'jaws I8 toward the right and inwardly toward the wire line 23 of the rod drawing machine. The springs 2| permit limited, spreading movement of jaws I8 toward the left so that a rod can be pushed manually between the jaws and toward the die II. When the carriage 9 moves toward the left and toward the die II, the jaws I8' are wedged against and tightly grip the rod 24 and force its leading end portion 25 through the die. When the carriage 9 is withdrawn toward the right away from die II and along theways I0, or when the rod 24 is pulled through the die I I by pull carriage I2, the grip of jaws I8 on rod 24 is loosened sunciently to allow the rod 24 to slide through the jaws.

The pull carriage I2 is mounted on two pairs of rollers 26 for movement along rails 21 toward and away from the die II. The carriage I2 is inrengagement with a pair of lead screws 29, each of which is connected through a gear train When the hydraulic vmotor 3l rotates, the lead y screws 29 rotate to move the carriage I2 toward or away from the die II depending upon the direction of rotation of the lead screws.

A pair of rod gripping jaws 32 are mounted in a pair of blocks 33 with ball bearings 35 disposed between their tapering surfaces. Springs 36 resiliently urge jaws 32 inwardly toward the right into engagement with the-rod end portion 25. As the Ycarriage I2 is moved toward the right and approaches the position shown in Figure 3, the jaws 32 can spread sufficiently to slip over the end of rod 24. When the carriage I2 is then moved toward the left to the position shown in Figures 1 and 2, the' jaws 32 are wedged into engagement with the rod and pull it through the die II. The greater the resistance of movement of the rod through the die, the more securely jaws 32 and jaws I8 grip the rod.

-The above described combination of die and push and pull carriages containing releasable rod gripping jaws forms no part of the present invention and other types of push and pull carriages and other arrangements of rod gripping means and dies may be used. The present invention is not limited to the rod drawing machine shown herein and is applicable to other types of rod drawing machines, such as headers, in which the rod is advanced through the die solely by being pushed.

Referring more particularly to Figures 3 and 4, the rod gripping jaws I3' and 32 and the die II are all disposed along and symmetrically arranged about the wire line 23 of the rod drawing machine. When the rod 24 is drawn properly without distortion, it is moved through the machine with its longitudinal axis coinciding with the wire line 23. The movement of both carriages is parallel with this wire line. As the push carriage 9 advances, the leading end portion 25 of rod 24 through die II, portion 25 is unsupported as it emerges from the die. At least at times, the leading end portion A29 will bend laterally away from the wire line. At times it may be possible to construct and arrange the die so that none or substantially none of the rods bend, but if a dierent dieis substituted, the rods may bend. "With any particular die, it has been found that those rods which are caused to bend by the die will all bend in the same direction. i

1 In accordance with the present invention, a rod straightening device shown generally at 38 is provided for straightening the end portions 25 of those rods which normally bend laterally away from the wire line 23 as a result of stresses set up in the rod by the die without distorting or deforming those rods which do not tend to so bend. A rod straightening device 38 is provided for each die I I. As these devices are all similar, only one will be described in detail. The die II is turned so that those rods which do bend, bend downwardly. A rod straightening guide or roller 39 is rotatably mounted on a pin 49 supported in a bracket 4I vertically, slidably mounted in ways 43 of retainer members 44. A lower member 45 is also vertically slidably mounted in ways 43 below bracket 4I. A screw 46 is adjustably mounted in lower member 45 with its head 4l engaging bracket 4I for adjusting the vertical position of roller 39. A set screw 49 is provided in member 45 for locking screw 46 in the proper position. The lower side of die holder 8 is slotted at 5U to receive a horizontally movable cam 5I. Cam 5I is held in place by plate 52 bolted to thebottomof die holder 8,.; Cam .5I includes a gee-ases i lower camsurface 53 and an upper cam surface 54 and extends through a slot 55 in lower member 45 so that member 451 and bracket 44 are supported on either cam surface 53 or cam surface 54. The cam 5I includes an elongated recess 51 containing a spring 58 and closed by a threaded plug 59. The opposite end ISI) of recess 5-1 is of reduced size and has slidably mounted therein an elongated pin 6I. A ball 62 is Ainterposed between the rear end of pin 6I and spring 58. A slot 63 is formed in the outerend portion of pin- 6I for receiving the end of a stop pin 64. Pin 54 limits movement of pinV 5I toward the left. Stop pins 65 and 61- 'are mounted in cam 5| and serve to limit the movement of the cam relative to holder 8.

Cam 5I projects beyond the die holder 8 toward push carriage 9 so that when they push carriage 9 is moved toward the die holder to push the leading end 25 of the rod 24 through die II, the carriage 9 pushes the cam toward the left. This movement of the cam 5| brings surface 54 beneath member 45 and raises roller 39 into position to engage the bottom surface of the rod to straighten and prevent the leading end portion 25 fromV bending downwardly and laterally away from wire line 23 asl itis pushed through the die. The straightening device, and especially screw 46 and. roller 39, are preferably so arranged that when the cam raises the roller 39 to thev operating position, the roller 39 bends the leading end portion of the rod upwardly and slightly beyond the wire line 23 so as to overcome the` stresses and strains set up in the rod by the die. should be bent upwardly beyond the wire line. will depend on a number of factors including the magnitude of the stresses caused by the die. At times, it may be. desirablev to have cam 5I and screw 46v so proportioned and arranged that the roller 39. only is raised far enough to bend the leading end portion of the rod upwardly sufiiciently to maintain the end portion straight as it emerges from the die and preventgit from bendingV downwardly away from the wire: line without. bending the rod portion 25 upwardly beyond the Wire line. With the roller 3,9 in either positiony and if the die tends to bend the rod downwardly as it is. pushed through-'the die, the roller tends to bend the rod upwardly and straighten the rod. Y

When the pull carriage I2 is moved toward the die. II to the position shown in Figure 3-, it engages the end of pin 6I and pushes cam 5| toward the right to the positions shown. As carriage I2 approaches the leading end portion 25 of rod 24, portion 25 normally will be at least The amount that rod portion 25 6T then the roller 39- need not be and preferably is not moved downwardly away from the rod until the end of` the rod has entered passage 68 and.

between jaws 32; Normally, it will not be necessary or desirable to bend the rod end up far enough so it cannot enter passage S8.

A long bolt is mounted i-nholder 8. with its lower end 1| extending into rod passage 12 on the exit side of die H. The end 1I of bolt 10 is positioned above thevwire line 23 a distance substantially equal to the radius of rod 24. When the rod straightening roller bends the end portion upwardly to straighten this portion, the rod engages the end 1I of bolt 10 to provide a three point support for bending the end portion straight. Whenbending an elongated member, a three point support is better than a two point suport. The bolt end` 1| prevents all bending of the rod taking place adjacent' the die I I. The

l bolt end 1|- preferably is slightly spaced above rod 24 Vso that it does not deface the rod as the pull carriage pulls the rod through. the die. A1- though bolt end 1I may touch rod 24 at all times, it should not exert enough pressure on the rod to deface the rod. When cam surface 54 raises roller 39 only far enough to bend the rod end upwardly sufficiently to maintain the end portion 25 straight and prevent the rod end from bending downwardly, theend of'bolt 10 aidsl in bending and maintaining portion 25 straight.

A complete cycleof operation will? now be described, it being understood that control apparatus of any type can be used to automatically control the operation of the cylindersV I8 and motor 3| or cylinders I8 and motor 3| may be manually controlled. At the start of the cycle, carriages 9 and I2 are in the position shown in FiguresV l and 2. Figure 3falso shows carriage 9 in position at the start of acycle of operation. Three rods 24 are each insertedv through a corresponding guide 1S at the right hand end of the close enough to being in alignment with the wire line 23 so thatV the end of the rod will enter between jaws 3'2. If the straightening device 38 including cam 5| is so constructed that the rod straightening guide or roller 39 bends the vend of the rod upwardly and beyond the wire line suiiiciently so that the rod' endA will not enter the. guide passage 68, then cam 5I must bemoved toward `the right sufficiently to lower roller 39A tothe inoperative position before the end of rod- 24 starts to enter the passage 68' leading to jaws 32. When the rod straightening deivce 38 and cam 5I. are soconstructed and arranged that the roller 39 maintains the forward end portion of the rod in a substantially straight horizontal line or only bends the rod end upwardly beyond the wire line such a slightv amount that the rod end Aenter Vpassage 68 and between-'thel"jaws` 32,-

machine and manually pushed through a guide 14 on carriage 9 toward the die I-. The forward end 25 of the rod is manually pushed between jaws I8" and pushed-forward until the end is against die II. Fluid under pressure is then admitted to the head ends of cylinders I8 to Y move carriage 9 along waysv l0' from its position shown in the drawings towardl the die II. As carriage 9 moves toward the die, it first strikes cam 5I and thenv moves it toward the'left to move cam surface 54 beneath .memberl 45 and raise roller 39 to the operative position. This movement or rst stroke of the carriage also moves the leading end portion of the rod through die II for a short distance. The ow of fluid to the cylinders I8 is then reversed and the cylinders move the carriage 9 toward the right and farther to the right than shown in the drawings. The cylinders I8 thereafter move the carriage 9 forwardly toward the left to the position shown in the drawings'. This last forward stroke may be repeatedv a number of times as the carriage 9 pushes'the rod through the die II, the roller 39 bends the leading end portion upwardly to straighten the rod and preferably bends the leading end slightly beyond the through the die II, motor 3|I is started to rotate lead lscrewsf 29- and move thev carriage-I2 Vfrom its position shown in Figure 1 toward its p0- sition shown in Figure 3. As carriage I2 appreaches die II, the carriage strikes the end of pin 6I and moves cam 5I toward the right to its initial position shown in the drawings. When cam 5I has been moved as far as pin B6 will permit any continued movement of carriage I2 will cause pin 6I to compress spring 58 which also acts as a safety means in the event carriage 9 is not properly located. Before roller 39 is lowered, the straightened end portion 25 which is preferably bent upwardly and slightly beyond the horizontal is nearly enough aligned with the guide passage 68 so Lthat upon movement of carriage I2 toward die II, the rod enters passage. When carriage I2 reaches the position shown in Figure 3, the rod end is between jaws 32 and roller 39 has been lowered and the motor 3I is reversed to move the carriage I2 to the left to the position shown in Figure 1. As carriage I2 moves to the left, jaws 32 grip the rod and pull it through die II. As the rod is being pulled by carriage I2 it is immaterial whether or not the rod tends to bend downwardly as it will be pulled straight. When the rod 24 has been completely drawn, it is removed from jaws 32 and the cycle repeated.

If cam surface 54 is of such a height or if screw 46 is so adjusted that roller 39 merely holds the rod end portion 25 horizontal or bends portion 25 slightly beyond the horizontal as it is pushed through the die II, then the length of pin 6I preferably is such that the rod enters guide passage 68 and preferably between jaws 32 before the roller 39 is lowered. When roller 3B is positioned to bend the rod end upwardly past the wire line suiiciently so that the end portion cannot enter passage 68, then pin BI is of such a length that roller 39 is lowered before the rod end enters passage 68.

I prefer to have the roller 39 bend the end portion slightly beyond the wire line so as to more nearly perfectly straighten the end portion by more nearly completely overcoming the stresses set up in the metal by the die. The degree to which the end portion is bent beyond the wire line will usually be very small but will depend at least in part on the properties cf the metal and the characteristics of the die.

When drawing rods other than rounds, such as, hexagons, it is desirable to have a flat surface on top to be engaged by bolt end II Consequently, it may not be possible or desirable to position die II so that the rods tend to bend vertically downward and it may be necessary to position the die I I so that the rod end bends downwardly and slightly to one side of vertical. Pins 'I5 are provided in holder 4I for laterally positioning roller 39. Usually pins 'I5 are positioned to align roller 39 directly below the rod, but when the rod end tends to bend downwardly and laterally, then pins I5 can be shifted to shift the roller 39 laterally so that the roller Will bend the rod end upwardly and laterally in the opposite direction.

When it is necessary to change the die, the new die first is fastened in place in the die holder. After one or more rods have been drawn, it will be apparent in which direction the new die causes the rods to bend and the new die can then be turned, if necessary, to cause subsequently drawn rods to bend downwardly. In those instances when the rods do not tend to bend even a slight amount as a result of die imperfections, the s traignte11-ing` deviceY wm not deform the rods.

Straightening the rod end portion 25 immediately after it passes through the die has been found to be much easier and better than straightening the end portion at a later period. When the rod is straightened immediately after being drawn through the die, age hardening of the metal which follows a colddrawing operation has not taken place and it is relatively easy to straighten the rod and overcome the stress and strains caused by the die. Age hardening of cold drawn rods is relatively rapid and apparently is-accelerated by the heat generated when the rod is drawn. If such a rod is bent while being drawn, it will age harden so that by the next day relatively heavy straightening equipment will be required to straighten the rod.

I claim:

l. In a rod drawing apparatus having a straight draw line, the combination comprising, a bench, a die having an entrance side and an ex' side disposed in a xed position along the draw line on the bench, a push carriage movable along the bench toward and away from the entrance side of the die for advancing the leading end portion of a rod through the die upon movement toward the die, said die having a tendency to bend the leading end portion of the rod laterally in a direction away from the draw line, a pull carriage on the exit side of the die movable along the bench toward the die into an engaging position with the leading end portion of the rod which has been advanced through the die and movable away from the die to draw the remainder of the rod through the die, rod straightening means disposed adjacent the exit side of the die, support means for mounting the straightening means for movement into and out of an operable position in which the straightening means engages the leading end portion of the rod to straighten the end portion upon being bent when the rod is being advanced through the die, and actuating means for moving the straightening means into the operative position during movement of the push carriage and out of the operative position during movement of the pull carriage.

2. The combination of claim 1 in which the actuating means includes means operable responsively to movement of the push carriage toward the die to move the straightening means into operative position and means operable responsively to movement of the pull carriage to move the straightening means out of operative posiion.

3. The combination of claim 1 in which the actuating means includes cam means actuated by means responsive to movement of the push carriage toward the die to move the straightening means into operative position and by means operative responsively to movement of the pull carriage toward the die means to move the straightening means out of operative position.

4. The combination of claim 1 in which a member is disposed along the draw line between the rod straightening means and the die in position to engage the surface of the leading end portion only when the rod straightening means bends the leading end portion beyond the draw line, such member then consituting the sole point of contact of the leading end portion with the apparatus between the die and the rod straighteningL means.

5. In a rod drawing apparatus having a straight draw line, the combination comprising. a bench,

a die having an entrance side and an exit side disposed in a fixed position along the draw line on the bench, a push carriage movable along the bench toward and away from the entrance side of the die for advancing the leading end portion of a rod through the die upon movement toward the die, said die having a tendency to bend the leading end portion of the rod laterally in a direction away from the draw line, a pull carriage on the exit side of the die movable along the bench toward the die into an engaging position with the leading end portion of the rod which has been advanced through the die and movable away from the die to draw the remainder of the rod through the die, rod straightening means disposed adjacent the exit side of the die. the rod straightening means being operable to engage the leading end portion of the rod to prevent the end portion bending when the rod is being advanced through the die by the push carriage, and a member disposed along the draw line between the rod straightening means and the die in position to engage the surface of the leading end portion only When the rod straightening means bends the leading end portion beyond the draw line, the member then constituting the sole point of contact of the leading end portion with the apparatus between the die and the rod straightening means.

LEE R. BERKEBIL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 191,100 Braukman et al. May 22, 1877 524,504 Robertson Aug. 14, 1894 524,508 Robertson Aug. 14, 1894 637,466 Jernberg Nov. 21, 1899 886,717 Moltrup May 5, 1908 1,298,999 Moltrup Apr. 1, 1919 1,940,354 Kerr Dec. 19, 1933 2,154,392 Barnhart Apr. 11, 1939 2,155,437 Moore Apr. 25, 1939 2,199,602 Wright May 7, 1940 2,360,746 Walker Oct. 17, 1944 2,363,406 Ferrier Nov. 21, 1944 2,404,234 Kerr July 16, 1946 2,434,006 Nye Jan. 6, 1948 2,492,544 Vetter Dec. 27, 1949