US2679925A - Drawbench - Google Patents

Description

June 1954 E. J. MCILVRIEQ ETAL DRAWBENCH Filed May i4, 1:47

INVENTORS EDWIN J. HILVRIED'r Aloe/1AM H .NVE.

4 Sheets-Sheet 1 q err-T012 Maya E. J. M ILVRIED ETAL June 1, 1954 DRAWBENCH 4 Sheets-Sheet 2 Filed May 14, 1947 BY MO ZMAN H NYE.

M v A77'OI2N'EYS June 1, 1954 E. J. MCILVRIED ETAL DRAWBENCH 4 Sheets-Sheet 5 Filed May 14. 1947 III INVENTORS ADW/A/ J. MIL 1 8/60- Av'rola/vsvs.

June 1, 1954 E. J. MCILVRIED ET AL 2,679,925

DRAWBENCH Filed May 14, 1947 4 Sheets-Sheet 4 54 g g """riiY/A.

INVENTORS saw/1v J. M: /1 1 2/50,- By MOE/VAN H. NYE

H7 7 O/ZIVEV.

Patented June 1, .1954

Edwin J. Mcllvried. an

d Norman H. Nye, ya-

hoga Falls, Ohio, assignors to The Vaughn Machinery Company, poration of Ohio Cuyahoga Falls, Ohio, a cor- Application May 14, 1947, Serial No. 748,083

1 This invention relates to draw benches and particularly to a device for initially feeding the tubular stock to be drawn into the drawing die and for controlling the mandrel position during the initial stage of the drawing operation.

In the drawing of tubular stock on draw benches in which the stock is pulled through the die by a traveling draw carriage,v the general 4 Claims. (01. 205-7) practice t swage down or otherwise reduce the leading end of the tubular stock to a diameter smaller than the die for a short portion of the length of the stock, the reduced end then bein passed through the die and gripped by suitable clamps on the drawing carriage preparatory to the drawin operation. Intermediate the reduced leading end and the normal diameter portion of the stock, the tube is tapered toward the leading end. The mandrel is supported in the tube in final position relative to the die prior to the start of the draw carriage. 'Accordingly, when the carriage is started on the drawing stroke, not only must it overcome the initial inertia of the tube and the high initial resistance of the material to flow, but also it must overcome the resistance caused by the metal piling up or thickening between the mandrel and the entrance of the die. Frequently, the combined effect of these resistances to initial movement of the tube is so great that the reduced end portion of the tube is pulled off at the start ofthe-drawing operation.

One of the objects of. the present invention is. to segregate these resistances so that the total instantaneous resistance to the drawing of the tube isgreatly reduced during the initial stage-of the drawin operation.

A more specific object is to draw the tube initially before entry of the mandrel into the die and, without interrupting the drawing movement of the tube, to move the mandrel into final position relative to the die. I

Another object is to provide a ,yieldable ;restraining means for delaying the movement of the mandrel into fina1 position in the die relative to the movement of the tube during drawmg.

Another object is to provide a means formoving the tube andmandrel together so as to position the tube in the die preparatory to the drawin operation and for delaying movement ofthe mandrel relative to the tube during-the initial part of the drawing operatic Another object is to position the mandrel accurately in positionrelative to the die during the drawing operation.

Other objects and advantages will become apparent from the following description wherein reference is made to the drawings in which:

Fig. 1 a diagrammatic side elevation of the stock feeding portion of a draw bench embodyin the rinciples of the present invention, the mandrel rods being omitted for clearness inillustration;

Fig. 2 is an enlarged fragmentary side elevation, partly in section, of the left-hand portion of the mechanism illustrated in Fig. 1;

Fig. 3 is an enlarged. longitudinal vertical sectional View through one ofthe feeding carriages of Figs. 1 and 2 and its mounting;

Fig. 3A is a fragmentary detail of the mandrel rod and connecting sleeve thereof;

Fig. 4 is a cross sectional view on line l-4 of Figs. 2 and 3;

Fig. 5 is a side elevation of those end portions of the feed carriage adjusting rods and their mounting nearest the die end of the draw bench;

Fig. 6 is a cross sectionalview taken on line 6-6 of Fig. 5;

Fig. 7 is a longitudinal sectional view of the tool used for adjustin the rods of Figs. 5 and 6 Fig. 8 is a fragmentary side elevation of one of the supports of the feed mechanism of Fig. 1;

Fig. 9 is a cross sectional view on line 99 of Fig. 8;

Figs. 10, 11 through 13 are diagrammatic longitudinal sectional views illustrating the steps of inserting the tube into the di preparatory to the drawing operation, twoinitial stages of the drawing operation, and a subsequent stage of the drawing operation respectively.

Referring to the drawings, the preferred embodiment of the invention is shown for purposes of illustration as incorporated in a draw bench feed mechanism of the general type disclosed in our co pending pplication Serial No. 514.9 6, filed December 20, 1943, now Patent No. 2,399,576.

As therein more fully described, the feed mechanism comprises generally a rigid elongated supportingframe I on which is mounted a rock shaft 2 which terminates at one end adjacent the die 13 of the draw bench. For rocking theshaft 2, a gearfi is rigidly secured to the end of the :shaft remote from thedie 3 and is engaged by a rack 5 which is driven inopposite directions, selectively,

by a hydraulic piston and cylinder assembly 6. Mounted fixedly on the shaft2 is block I having slideways 8 extendin parallel to the shaft 2, as b st illustra ed in Fig- 4. In th form illustrat d two parallel sets of slideways 8 are provided.

Mounted on the slideways 8 are duplicate feed- 3 ing carriages, designated generally at 9, the carriages being mounted diametrically opposite from each other, one carriage on each set of slideways. The carriages 9 are movable independently of each other back and forth along the associated guideways.

Each carriage 8 comprises a rigid frame it having at its forward end a latching flange H, later to be described. Mounted on each carriage a for adjustment longitudinally thereof are housings 12 to each of which is detachably' connected a mandrel supporting rod I 3. Each rod [3 is anchored firmly to its associated housing l2 by means of a removable sleeve and set screw assemblage Hi. In order to adjust the position of the housings (2 on the carriage 9, individually, each housing 52 is provided with a bore of which the forward end is threaded for cooperation with an adjusting screw i5. Each screw 15 is mounted for rotation in fixed axial position in the carriage 9 and is connected to an adjusting rod i6 which extends parallel to the shaft 2 toward the die end of the feed mechanism.

At the die end, each rod I6 is provided with a collar H which is rotatable with the rod and which has a suitable lug l3 and pilot portion l?) which are engageable by a suitable tool 20, as illustrated in Fig. 7, for rotation of the rods. With this arrangement, the position of the car riages i2 and the mandrel rods carried thereby can be adjusted from a location adjacent the die 3. The die ends of the rods 45 are mounted in a suitable slip mounting 2! which is slidable on the shaft 2 so as to move with the feed carriage 9.

Each housing 12 is provided with a tubular rest 22 which extends forwardly therefrom through a suitable opening in the flange H and which is open at the end nearest the die for receiving the trailing end of a length of tubular stock :3 to be drawn.

At spaced points along the length of the shaft 2 are rotary supports such as illustrated in Figs. 8 and 9. Each support comprises a pair of rollers 23 which are mounted on the frame Secured to the shaft 2 is a disc 24 having a circular periphery which rolls on the rollers 23. Suitable bushings 25 are mounted in openings in the disc 26 to afford passage of the adjusting rods l6. Also each disc is provided with ports 26 which preferably flare outwardly toward the die end of the mechanism to permit passage of the stock S therethrough over the mandrel rods and to guide and support stock preparatory to insertion of the leading end of the stock into the die.

Since the shaft 2 can be rotated through 180, one carriage 9 is in a rotated position for charging with stock to be drawn while the other is in a rotated position in which its mandrels and the stock lengths with which it is charged are aligned with respective drawing ports of the die 3. The carriage being charged is in a fully retracted position relative to the die, as shown at the top in Fig. 2, and the carriage feeding the stock, shown at the bottom in Fig. 2, is in the fully advanced position in which it remains during the drawing operation, except for the initial stages.

In order to advance and retract the carriages 9, a single propelling device is employed. This device comprises a slide head 30 mounted on a suitable slideway 3| on the frame I for movement back and forth parallel to the shaft 2. The slide head is actuated by a double acting piston and cylinder assemblage 32 to which it is operatively connected by a rod 33.

The slide head 30 has an upwardly open notch 34 which may be formed in a suitable member 35 carried by the head 38. If desired, the member 35 may be mounted for vertical movement in the head 30 and held upwardly by suitable yieldable means.

The notch 34 extends in adirection transversely of the shaft2 and is arranged to be engaged by the flange H of either carriage 9 when the particular carriage is revolved about the shaft 2 to the lower, or feeding, position.

InFig. 2, the slide 36 is shown in the fully advanced feeding position, but normally it occupies a fully retracted position in which the notch 34 is directly beneath the flange of the fully retracted upper one of the carriages 9.

With the structure thus far described, lengths of tubular stock S to be drawn are slid open end foremost from the die end of the mechanism over the mandrels and the associated rods [3 of the upper carriage 9 until the inner walls of the tapered ends of the stock engage the forward ends of the mandrels, the open end portions of the stock being supported in the tubular rests 22. The stock lengths are supported at spaced points along their lengths by the discs 24. This operation is performed while the upper carriage 9 is fully retracted and while the lower carriage 9, in Fig. 2, is operative for feeding. At the end of the feeding operation, the slide 30 has been fully retracted and is in a position such that, when the shaft 2 is rocked through the flange H of the charged carriage enters the notch 3d of the slide head 36. In this condition, the piston and cylinder assemblage 32 is operated to advance the slide head 39 and move the carriage 9 forwardly toward the dies 3 so that the mandrel rods. due to engagement of their mandrels with the tapered forward end walls of the stock, push the tapered ends of the stock through the dies 3.

Normally this movement would continue until the tapered ends of the stock had passed through the dies and the mandrels were in final drawing position within the dies, respectively, Thus, as explained above, the drawing operation would have to be initiated against the combined stresses described. In order to eliminate these difficulties, a control mechanism now to be described is provided.

In the form illustrated, this mechanism comprises a hydraulic cylinder 40 which is connected to the frame I and is adjustable in a direction parallel to the shaft 2 by a suitable adjusting screw 4 I. Within the cylinder 49 is a piston head 42 having coaxial piston rods 43 and 44 extending in opposite directions therefrom. A coil spring 45 is mounted in the cylinder 49 and urges the piston head 42 toward the assemblage 32. Normally, under the influence of the spring 45, the piston head is in a fully extended position which is at the extreme left-hand end of the cylinder in Fig. 2.

The piston rod 43 extends out of the casing and parallel to the path of travel of the slide head 30 and is arranged to be engaged at its outermost end by the flange i I of whichever carriage is being driven by the slide head 30. The cylinder 40 and piston 32 are so positioned endwise of the shaft 2 that the flange H engages the rod 43 near the end of the advance movement of the carriage 9 and moves the piston head 40 and rod 44 toward the die end of the mechanism until the rod 44 strikes the end of the cylinder 40 and stops further movement of adv-9,925

the carriage 9 and slide head 3.0 toward the dies 3.

By adjustment of the housings E2 on the carriage '9. and of the cylinder All on the frame 1, engagement of the stop rod Ml and end of the cylinder 48 occurs when the mandrels are fully advanced into the dies.

Upon retraction of the slide head 38 by the assemblage 32, the spring restores the piston head 42 and rod 53 to their starting positions.

In order to resist movement of the piston head 42, to the right hand in Fig. 2, by the flange H, the right hand end of the cylinder at is connected by a suitable pipe line as to a supply tank ll. Connected in the line as between the tank d? and cylinder it, and in series with each other, are a solenoid operated valve :18 and an. adjustable throttling valve 49. Also, connected in the line 45 between the cylinder at and tank 41 and in by-passing relation to the valves 58 and 49, is a Icy-pass line all in which is a check valve The check valve 5! is operative to admit fluid freely from the tank 4'! to the cylinder 49 around the valves 48 and 49 and to prevent return of the fluid through the by-pass line 58 from the cylinder 4a to the tank 61.

Thus, when the piston head 42 is moved to the left in Fig. 2 by the spring 45, the right hand end of the cylinder draws in a charge or oil or fluid freely so that the movement of the piston to the left is very rapid. When, however, the piston is driven to the right by the flange ii, the fluid escapes from the right end or" the cylinder 43 only through the throttling valve ie, which greatly slows down its movement. cylinder 46 and assemblage 32 are so related that the piston 42 and rod 53 can slow down to any desired degree the normal rate of movement of the slide head to to the right after engagement ofthe flange H and rod 53.

If further control is desired, the solenoid valve 48 may be made operative therefor. For example, the solenoid valve d3 may be normally open and connected by suitable electric lines 52 to a switch '53, illustrated in Fig. 1, which is normally open but which is positioned to be closed by the draw carriage 5d of the draw bench when the carriage is in final position for receiving the tapered end of a piece of stock S to be drawn. When the switch 53 is thus closed, the

solenoid valve is energized and held in closed position. This completely blocks the hydraulic circuit to the cylinder 59. The switch 53 is arranged to open when released by movement of the draw carriage 54 a slight distance, to the right in Fig. 1, away from the dies 3. inching switch is connected in series between the switch 53 and solenoid valve 52 so that, even with the switch 553 closed, the valve 52 can be opened by the operator.

The reasons for and operation of the mandrel control and delaying mechanism is best described by reference to Figs. through 13.

In Fig. 10, the reduced portion of the leading end T of the tubular stock S has been pushed through the die 3 by engagement of the mandrel 5? with the tapered walls of the stock and advancement of the lower feeding carriage 9 by the assemblage 32. The clamp of draw carriage 54 has gripped the protruding reduced end portion of the tube and has started to move toward the right at a greater rate than the mandrel.

In this position, the flange H is pressing against the rod 43, but the switch 53 is held closed by the carriage 54 so that the valve 455 is closed and the hydraulic circuit to the cylinder 40 is A manual blocked. The piston head 42 is at the extreme left. By operation of the inching switch-5.5, "the reduced end of the stock is moved into proper position in the clamp of the carriage 54 and clamped. The assemblage 32 is operativeduring all this period to urge the carriage 9 to the right against the resistance of the rod' 13. Movement of rod 53 is of course resisted by spring and, of more importance, controlled by permitted flow of fluid to tank 41..

After the stock is secured to the draw carriage 5d, the carriage is driven to the righton its drawing stroke, usually by hooking it to the usual chain drive, not shown. Almost at once, the carriage releases the switch 53, opening the solenoid'valve 58 so that the hydraulic circuit is opened through the throttling valve 49. Thereupon the carriage 9, and therefore the mandrel 5? are moved to the right by the assemblage 32 but under the control of the piston t2 and cylinder 48. The throttling effect of the valve 49 is so adjusted that the mandrel advances in the drawing direction at a slower rate than the tubular stock T is advanced by the carriage 54. Thus the mandrel enters the die only in time delayed relation to the initiation of the actual drawing movement of the stock.

Accordingly, from the position illustrated in Fig. 10, the stock moves to the position illustrated in Fig, 11, but the mandrel 51 lags behind the stock so that the initial thickening of the stock wall at U due to reduction in the stock diameter occurs before the mandrel enters th die sulficiently far to be operative. Thus the inertia of the stock on starting is overcome first and is followed by the initial flowing of the metal accompanied by initial elongation of the stock, and by initial upsetting and thickening of its walls, due to reduction of its diameter by the die, all before the mandrel has moved to operative position. Consequently these initial steps are performed without the added resistance due to jamming of the thickened walls between the mandrel and die which would have occurred had the mandrel moved into the die from the position of Fig. 10 at the same speed as the stock.

Th movement of the closed end of the stock progressively farther ahead of the mandrel, due to the slower speed of movement of the latter, continues through the position illustrated in Fig. l2 and until the mandrel is fully inserted and stopped in final operating position in the die, as illustrated in Fig. 13.

Thus, without any interruption or change inthe speed of travel of the stock through the die, the mandrel is gradually inserted to final position as illustrated in Fig. 13 so that the resist ance to drawing of the stock builds up gradually and smoothly. When the mandrel is in the fully inserted position illustrated in Fig. 13, the rod 44 is against the right hand end'of the cylinder 46 so that further travel of the mandrel in the drawing direction is prevented.

When the stock is fully drawn, the working fluid to the assemblage 32 is reversed, whereupon the slide head 39 and lower carriage 9 is fully re-- tracted. The piston 42 and rod 43 ar restored rapidly to starting position by the spring :5 and free admission of fluid to the cylinder 43- through the check valve 5!. The switch 53, and consequently the solenoid valve remain open until the draw carriage 54 is again returned to starting position.

If desired, the. rocking of the shaft 2 may be controlled by a valve operated by a rod 6| 7 which is engaged and moved in one direction by the slide 30 when the latter is moved to its starting position at the left in Fig. 2, the rod being restored by a spring 62.

Obviously, with the adjustments provided, any desired relative positions of the stock, mandrel, die and draw carriage, preparatory to starting of the drawing operation can be obtained and both the initial entry of the mandrel into the die relative to the amount of previous movement of the stock, and the rate at which the mandrel advances in the die relative to the advance of the stock during the drawing operation can be controlled.

In order to lubricate the mandrel head, a fitting 65 and flexible conduit 66 are connected to the housing 12 and supply lubricant under pressure thereinto. A suitable packing is installed adjacent to the fitting 65 to prevent the escape of the lubricant from the open end of the housing 12. The mandrel rod is of the usual hollow type and the mandrel head is provided with th usual ducts communicating with the interior of the rod and with the usual discharge ports 63 so that lubricant admitted into the rod passes through the rod and out of the ports 63 of the mandrel 51 onto the inner surface of the tube in advance of the point at which the tube is reduced about the mandrel 51. One or more radial ports 64 are provided in that portion of the rod i3 which is within the housing [2 for admitting tthe pressure lubricant from the interior of the housing into the interior of the rod, as illustrated in Fig. 3.

Having thus described our invention, we claim: 1. In tube drawing mechanism of th typ having a, die, a mandrel reciprocable into and out of cooperating position in said die, means operative to advanec said mandrel into such position, and drawing means operative to grip the reduced leading end portion of such tube when the latter has been inserted through said die and to pull such tube through said die; the combination of means automatically operative to stop advance of said mandrel when the latter has advanced sufficiently to insert such reduced leading end portion of such tube through said die into position to be gripped by said drawing means and before said mandrel has entered said die, means operative in timed relation to initiation of drawing movement of said drawing means to release said mandrel for further advance by said mandrel advancing means, and means operative automatically to limit the rate of such further advance of said mandrel to a speed no greater than the rate of movement of such tube toward said die produced by movement of said drawing means.

2. In tube drawing mechanism of the type having a die, a mandrel reciprocable into and out of cooperating position in said die, fiuid pressure piston-cylinder means operative to advance said mandrel, and drawing means operative to pull such tube through said die; the combination of a second piston-cylinder assembly adapted to oppose such advance of said mandrel by said first piston-cylinder assembly when the latter has advanced said mandrel adjacent said die but not yet to operative position therein, a throttling valve adapted to regulate escape of fluid from the cylinder of said second piston-cylinder assembly, said valve normally being closed when said mandrel is thus initially advanced toward said di so that further advance is prevented, and means operative to open said throttling valve in timed relation to initiation of the drawing operation by said drawing means to permit further, but regulated, advance of said mandrel into operative position in said die.

3. A tube drawing mechanism having a die, a mandrel reciprocable into and out of cooperating position in said die, means connected to said mandrel for moving the same toward said die, drawing means operative to grip the reduced leading end portion of a tube when the latter has been inserted through said die and to pull such tube through said die; a controlled yieldable stop positioned in the path of said mandrel-moving means to be engaged thereby when said mandrel is in a position adjacent said die to oppose further movement of said mandrel-moving means, means to control the yieldability of said stop to regulate further movement thereof and thereby adjustably resist the advance of said mandrel by said mandrel-moving means, said means to control normally preventing yieldability of said stop, means engageable by said drawing means operative to activate said means to control to permit further regulated advance of said mandrel in timed relation to initiation of the drawing operation, and means to limit the maximum yieldability of said stop to fir; the final position of said mandrel in said die.

4. A tube drawing mechanism having a die, a mandrel reciprocable into and out of cooperating position in said die, fluid pressure piston-cylinder means connected to said mandrel for moving the same toward said die, drawing means operative to pull a tube through said die and over said man drel; a second relatively movable piston member and cylinder member assembly having one of said members located in the path of movement of and to be engaged by said first fluid pressure means to oppose such advance of said mandrel by said first piston-cylinder assembly when the latter has advanced said mandrel adjacent said die but not yet to operative position therein, a spring adapted to urge the said one member of said second piston-cylinder assembly to extended position for the aforementioned opposition of said mandrel, stop means adapted to limit inward movement of said one member and thereby to determine the final position of said mandrel in said die, a throttling valve adapted to regulate escape of fluid from the cylinder of said second pistoncylinder assembly, said valve normally being closed when said mandrel is thus initially advanced toward said die so that further advance is prevented, and means operative to open said throttling valve in timed relation to initiation of the drawing operation by said drawing means to permit further, but regulated, advance of said mandrel into operative position in said die.

References Cited in the file of this patent Great Britain June 13, 1946

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