US2192785A - Method and apparatus for drawing rods and wire - Google Patents

Description

2,192,735 METHOD AND APPARATUS FOR DRAWING RODS AND WIRE S D N O B A Filed Aug. 28, 1953 4 Sheets-Sheet 1 Z fiLBEEr BOA/D6 METHOD AND APPARATUS FOR DRAWING RODS AND WIRE s D N O B A Filed Aug. 28, 1953 4 Sheets-Sheet 2 #4 55/37 BOA/D5 METHOD AND APPARATUS FOR DRAWING RODS AND WIRE A. BONDS Filed Aug. 28, 1933 4 Sheets-Sheet 5 [meal 07': 144 BERT BOA/D6 METHOD AND APPARATUS FOR DRAWING RODS AND WIRE S D N O B A Filed Aug. 28, '1933 4 Sheets-Sheet 4 fnvenfor: #4 BERT BOA/D6 Patented Mar. 5, 1940 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR DRAWING RODS AND WIRE Application August 28, 1933, Serial No. 887,227

14 Claims.

This invention relates to a method and apparatus for drawing rods and wire.

In the drawing of commercial rods and wire, the compression of the material occasions a great deal of wear to and friction energy loss at the die. In addition, considerable difllculty is experienced in admitting a sufficient quantity of lubricant to the die.

It has been found that, if the material being drawn is tensioned throughout its length during the drawing operation, i. e., tensioned upon the entrance side of the die as well as upon the exit side thereof, frictional energy loss at the die is reduced, approaching zero when the tension attains or exceeds the yield point of the material. Ordinarily such tension, because of the drag it imposes on the material upon the entrance side of the die, increases the amount of energy that must be expended to draw the material through 50 the die, which increase in energy ordinarily is greater than the energy savings effected by the reduction of the frictional energy losses at the die. However, by applying this principle to tandem drafting operations, such tension on the a material can be utilized to assist in drawing the material through preceding dies, whereby the increased energy requirements such tension im- Doses at the final drafts thereof, is offset, leaving the net power requirements less by the amount 9 of the frictional energy reductions at the dies,

as compared with similar drafting practices without tension.

lit is the primary object of the present invention to provide a method and apparatus for drawa ing rods, wire, and other elongated metal stock, So as to reduce the frictional energy losses at the dies.

It is another object to provide a method and apparatus for drafting elongated metal stock 40 whereby the energy usually expanded at the dies, unutilized in the form of frictional heat, is made to assist in the work done during the drafting operation, whereby the net power input is substantially less than would be realized in the absence of tension.

It is another object of the invention to pro- Vlde a method and apparatus for drawing elongated metal stock so as substantially to reduce the compressive stress occasioned by the die, and further to facilitate the translatory movement such material effects upon blocks or capstans ployed for the drafting operation, thus appreciably to minimize the wear upon such blocks or capstans. Another object of the present invention is to provide a novel means for accomplishing the drawing of rods and wire in such manner as to obtain an exactly proper amount of back tension" (so-called by virtue of its application upon the entrance side of the die) immediately before 5 the material enters the die.

Another object is the provision of novel means for maintaining constant the desired amount of "back tension, reducing to a minimum the wear on drawing dies, and also the possibility of break- 10 age of the material being drawn.

A further object is to provide a novel means for permitting the admission of much greater quantities of lubricant into the drawing portion of the die with the result that a decidedly su- 5 perior product will be obtained.

These and further objects will be apparent after referring to the drawings, in which:

Figure l is a plan showing part of the appa ratus of the invention. 2

Figure 2 is an elevation of the apparatus of Figure 1.

Figure 3 is a fragmentary plan, on an enlarged scale.

Figure 4 is an elevation igure 3.

Figure 5 is a sectional view on the line V--V of Figure 4.

Referring more particularly to the drawings, the numeral 2 designates a bed in which there are rotatably mounted a plurality of vertically disposed shafts 3, 4, 5, 6 and I. A conventional wire drawing block 8 is keyed on the upper portion of each of the vertically disposed shafts 3, 4, 5 and 6, while the shaft 1 has mounted thereon a take-up block 9 which is adapted for the application of the usual type of stripper device.

Each of the shafts 3, 4, 5, 6 and 1 is provided with a worm gear i0 adjacent its lower end which is driven from a motor i2 having a driven shaft I4 on which there is mounted a cooperating worm l5. Each of the motor shafts i4 is provided with a cooling fan i6 which functions through suitable conduits to cool its respective wire drawing block.

On one end of the bed 2 there is mounted the usual form of snarl" switch I! which functions to discontinue the operation of all of the motors i2 if a kink is encountered in the wire being drawn, the latter being represented in the drawings by the numeral A. A wire drawing die i8 is mounted adjacent the "snarl" switch H.

A vertically disposed shaft i9 is mounted in the bed 2 adjacent each of the wire drawing of the showing of 25 blocks 8, and has an arm secured thereto which carries a "dancer" sheave 2|. An arm 22 is likewise secured to each of the shafts l3 and carries a hook 23 on its opposite end.

A lower arm 24 is carried on the lower end of each of the shafts l9 and has connected thereto a rod 25 which is disposed within a tube 28 having an enlarged head 21 on one of its ends. A slot 28 is provided on each side of the tube 23 which carries a spring 29, the latter being held between the head 21 and a pin 30, which extends through the shaft 25 and. rides in the slots 28. The other extremity of the tube 26 extends through the side of the bed 2 and is threaded as at 3|, a nut 32 being provided for positioning the tube in such manner as to compress the spring 29.

A spring 33 is connected to the arm 22 to influence its movement in the opposite direction.

Each of the motors l2 has an adjacent rheostat 34 for controlling the same. Each of the rheostats 34 has the usual operating shaft 35 to which there is secured a sprocket 36. An idler sprocket 31 is mounted relatively adjacent the sprocket 36 and a chain 38 strung between them. The hooks 23 of the various arms 22 are connected to one of the chains 38.

A stationary sheave 39 is mounted on the bed 2 adjacent each of the dancer sheaves 2i, and a wire drawing die 40 is disposed on the bed between each of the stationary sheaves 39 and the neighboring wire drawing block 3.

In accordance with the usual practice, a safety plate 4| is mounted on one side of the top of the bed 2 and is mechanically connected in any suitable manner to an electric master switch (not shown) for stopping the entire machine if the operator should get caught by the wire and be pulled around one of the blocks, the movement of his body against the plate serving to stop all of the motors l2. The operation of the devices of the invention is started by means of 'a. conventional foot operated starting shipper rod 412 and a hand operated shipper rod it, which are connected in any suitable manner to master switches (not shown) a similar device being also provided for the snarl switch it.

In operation, the material to be drawn, which is illustrated in the drawings as a wire A, is threaded through the snarl switch H, the adjacent wire drawing die, and is wrapped a number of times (preferably seven) around the wire drawing block 8 on the shaft 3. From the first wire drawing block 8 the wire is next wound about three-quarters of a turn around the dancer sheave 2|, thence around the stationary sheave 39, through the second drawing die 40 and is wrapped around the second wire drawing block 8, which is mounted on the shaft 4, the same number of times as was the case on the first drawing block.

The wire A is similarly handled with respect to any desired number of sets of drawing blocks and dies, four of which are nominally illustrated in the drawings.

As the wire is threaded through the last drawing die 40 it is finally wound up to finished size on the last block.9, which, as before stated, is adapted for the application of the usual type of stripper device for removing the wire.

As the operation is carried on, the correct amount of back tension is set up by the various dancer sheaves 2| in cooperation with the stationary sheaves 39, which may be regulated by adjusting the tension of the springs 29 through the nuts 32. Any degree of tension that is suflicient to reduce the frictional energy losses at the dies up to the ultimate tensile strength of the material, or, more practicably, up to the yield point of the material, will bring about the reduced power requirements and give an' increase in die life mentioned in the forepart of this specification. Thus, it is not intended that the invention be limited to any exact degrees of tension within these limits, so long as a substantial-amount of tension is imposed. In actual application, the magnitude of the tension applied is such that, when combined with the reduced compressive stress of the die, a total force equal to about of the breaking load of the material being drawn is required forward of the die to pull it through. This gives a 20% margin 01 safety against breakage of the material, while, at the same time, accomplishes a drastic reduction in the compressive stress of the die,

Theoretically, if the blocks or capstans could be driven at constant speeds, operating in accordance with a predetermined differential rate, and all forces entering into the drafting operation were invariably stable and constant, the tension could be maintained between the blocks and dies throughout the entire length of wire independently of any other means, such, for instance, as the dancer sheaves. However, the forces and other factors entering into the operation necessarily vary through certain ranges, the exact extent of which cannot be ascertained beforehand, and, consequently, a tensioning means must be provided that will maintain a constant tension, while, at the same time, compensating for these variables.

Any variation in the back tension on the wire A as it progresses through each of the dies til moves the dancer sheaves 2! in such manner as to swing the arms 22, with the result that the hooks 23 engage the chains 38 and thus adjust the rheostats 34. This provides for automatically adjusting each of the motors l2 to modify the rate of rotation of the wire drawing blocks 8 and thus serves to obtain a constant back tension.

From the foregoing description it will be appreciated that each dancer sheave 2| does, by virtue of its compression spring 29, tension the wire being drawn so as to lower the compressive stress in the next succeeding die 40. This tensile force, extending as it does in both directions along the wire, is effective in unloading (by exerting a tangential pull in the direction of the wires movement) the preceding block or capstan 8. Although it could be provided, the first draft, as illustrated, is not provided with any back" tensioning means, whereby, although the frictional components at the first die are not lowered, the first capstan motor has less work to do than any of the succeeding block motors by virtue of the absence of the retarding effect of such back tension, and because of the relief afforded this block by the first dancer sheave. The second block motor must overcome the tension exerted by the first dancer sheave, and is assisted in this, first, by a lowered die reaction at the second die, and, secondly, by the action of the second dancer sheave that is, in the order in which the Wire passes through the machine, ahead of the second block. Thus, the boosting effect of the second dancer sheave offsets the retarding efiect of the first dancer sheave, in so far as the second block is concerned, leaving, as a direct result, the lowered die reaction at the second die, and a net power saving at the second block motor, as a consequence.

In similar manner does the second dancer sheave act with respect to the third block and the third dancer sheave, etc., and so on throughout the several drafts, until the final draft is reached. It will be noted that the last block or take-up capstan does not have a. dancer sheave succeeding it to assist in the turning thereof, whereby the power requirements of the last block motor are higher than are the requirements of any preceding block motor. This, however, is compensated for by the extraordinarily low requirements of the first block motor (by virtue of that which has already been explained above) so that the effect of the tension on the over-all power requirements is substantially nil, except for its result of reducing the reaction forces in the several dies, whereby the not power requirements are lower for effecting the entire reduction than would be the case if such tension were not employed.

From the foregoing, it will be seen that the tensile force, with respect to its application before and after each capstan, and before and after the last and first capstans, respectively, is self-negating, balancing out so as not to aflect, favorably or adversely, the torque items of the several capstans. This leaves the reduced reaction pressuresat the dies the only direct result, and lowered power requirements at the capstan motors as the corollary result. Considered another way, the lowered power input from motor to capstan, in each case, may be said to be attributable to power derived from the tensile force of the wire in motion, which represents a power factor that is complementary to that derived from the motors, and which combines therewith to draw the wire through the dies. In this connection, the wire being drawn can be thought of as a medium for power transmission from the last capstan or block to any preceding capstan, much in the way a belt transmits power from the driving to the driven pulley. The corollary to both of these latter may be expressed by the proposition that the energydegeneration, represented by frictional heat at each die, is minimized, and the energy thus spared is effectively utilized to assist in the ad-- vancement of the wire through the dies. In any case, the net power input from motor to capstan is appreciably less than would be required were there no tensile force acting upon the moving wire, and, hence, it is said, power is actually saved.

The tension exerted upon the wire by the dancer sheaves H has the further advantage of snnbloing the wire about each of the blocks, so that less turns of wire about each block is permissible without sacrificing adequate frictional engagement to prevent slippage, whereby wire translation is facilitated, and wear upon the blocks is greatly minimized, as well as the die life greatly enhanced.

While I have shown and described one specific embodiment of my invention, it will be understood that I do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of my invention, as defined in the following claims.

I claim:

1. The continuous method of drawing rods and wire which includes passing the material to be reduced through a plurality of graduated dies, establishing tensile forces of substantial magnitudes in said material at a plurality of points to materially reduce the reaction forces in each of the dies next succeeding the points of application of said forces, further utilizing said tensile forces by the application of outside power to generate energy, complementing said outside power with said energy to draw said material through all of said dies in a continuous manner.

2. The continuous method of drawing wire which includes passing said wire through a plurality of graduated dies to reduce the same, applying tension to said wire adjacent the entrance of each of said dies of a magnitude to materially reduce the frictional forces in each die, applying energy to said wire on the exit side of each of said dies to draw said wire continuously in one direction therethrough, said energy representing the total power expended to effect the entire reduction and being derived from an outside power source complemented by the energy represented by said tension of the wire in motion.

3. The continuous method of drawing rods and wire which includes passing the material to be reduced through *a plurality 01 dies, tensioning said material throughout the entire por tion thereof between the first and last die to materially decrease dle friction and to complement the power applied to draw the material through all the dies, said method being characterized by the fact that the summation of all power expended to draw the material through each of the dies is materially less than the total power expended to efl'ect the same reduction of he same material without tensioning the same throughout its entire length.

4. The continuous method of drawing wire which includes passing the wire through a plurality of dies and about a plurality of drawing blocks in successive alternation, establishing a tensile force of substantial magnitude in said wire before several of said dies to materially reduce the frictional component of each of the dies next succeeding the points of application of said force, and further utilizing said force for conversion into energy incident to the application of outside power to draw said wire, complementing said outside power with said energy to drive said blocks to effect a continuous feeding of the wire with minimum consumption of outside power, said method being characterized by a net power saving whereby the total power expended to effect the entire reduction is appreciably less than that amount of power required to efiect the same reduction of the same material without application of the tensile force aforementioned.

5. Method of drawing wire which comprises pulling the wire through a series of dies by tensions applied to the wire on the exit sides of the dies, applying back pull tensions to the wire on the entrance sides of the dies, and limiting the tensions applied to the wire on the exit sides of the dies to amounts less than sufilcient to pull the wire through the dies in the absence of .the back pull tensions.

6. Method of drawing wire which comprises pulling the wire through a die by tension applied to the wire on the exit side of the die, applying a tension substantially approaching the tensile strength of the metal in the opposite direction to the wire on the entrance side of the die in order to reduce die friction, utilizing the power developed in applying the tension to the wire on the entrance side of the die to reduce the total power required for drawing the wire through the die and limiting the total power supplied for pulling the wire through the die to an amount less than suflicient to pull the wire through the die in the absence of the tension applied to the wire on the entrance side of the die.

7. Method of drawing wire which comprises pulling the wire through a. die by tension applied to the wire at the exit side of the die, applying a tension substantially approaching the tensile strength of the metal in the opposite direction to the wire on the entrance side of the die, and limiting the total power supplied for pulling the wire through the die to an amount less than sufficient to pull the wire through the die in the absence of tension in the opposite direction.

8. Method of drawing wire which comprises pulling the wire through a series of dies by tensions applied to the wire on the exit sides of the dies, applying back pull tensions to the wire on the entrance sides of the dies, and limiting the energy applied to the wire on the exit sides of the dies to amounts less than suflicient to pull the Wire through the dies in the absence of the back pull tensions,

9. A wire drawing machine comprising a plurality of dies, a plurality of capstans, means for driving said capstans from a common source of power, the connections between said capstans and said source of power including means for limiting the torque applied to each capstan by the source of power to an amount less than sumcient to pull the wire through the preceding die.

10. A wire drawing machine comprising, in combination, a plurality of dies, a plurality of capstans located between said dies, means for driving said capstans, and means for limiting the torque applied by said drivemeans to each capstan to an amount less than suflicient to draw the wire through the die immediately preceding the capstan.

11. A wire drawing'machine comprising a die, means for pulling wire through the die, means for applying a substantial back pull to the wire on the entrance side of the die, and means or limiting the energy exerted by said first mentioned means to an amount less than suflicient to pull the wire through the die in the absence of back pull.

12. The method of drawing elongated metal stock which includes passing the stock through two reducing dies, tensioning said material between said dies so as to aid in pulling the stock through the first die, and to resist its passage through the second die an amount sufficient to reduce the frictional energy expended at the latter.

13. The method of drawing elongated metal stock which includes pulling the stock through a plurality of dies, tensioning the stock while in motion so as to resist its passage through at least some of said dies, while assisting in its passage through other of said dies, and maintaining said tension at a suflicient value to lessen substantially the total frictional energy expended at the dies.

14. Apparatus for drawing elongated metal stock comprising a plurality of dies, individually powered capstans interposed between said dies, a driven take-cit block positioned after the last die, means for controlling the speed at which said capstans are driven in relation to said takeoff block to maintain the stock served thereby under sufiicient tension materially to reduce the reaction forces of the dies through which said stock passes under tension.

ALBERT BONDS.

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