US2708024A - Wire drawing apparatus - Google Patents

Description

May 10, 1955 G. BRYDEN WIRE DRAWING APPARATUS 2 Sheefs-Sheet l Filed Oct. 30, 1948 8% ATTORNEY May 10, 1955 G. BRYDEN 2,708,024

WIRE DRAWING APPARATUS Filed Oct. 30, 1948 2 Sheets-sheet 2 l N V E NTO R 660ML" BWM/v ATTO RNEY ite States i atent Motte24 when uunwnio APPARATUS iryden, Elmwood, Retfoid, England, assigner Marshall Richards Machine Company Limited,

Crock, n British company Application @stellar Sli, 1943, Serial No. 57,535 Claims priority, application Great Britain July Ztl, 1943 1 Claim. (Cl. 20S-i4) rlhis invention relates to u process and apparatus for drawing wire und more rurticularlv to a rnu icle die process and apparatus for drawing wire in which a high degree of 'oe-.cli tension may be mainte- 'led on the wire during the drawing o; possible higher drawing speeds and rc oclug substantially the wear on the dies. This applic.. is a connuuatifu-in-part of my application Sensi No. 'filed .uiy 7., i947, now abandoned.

The principle of epoljnl o on wire that is bein., nized heretofore as ravi heavy bach tension ucilit reduction i uhstantisl haci; tension h a die hns heen recogfluvannees because t e frire and s through the die. could applied to the wire to piece it under a tension closely approaching ils ultimate strength, the worifA done b the die during tical beerssse scorinfz oit' the pu An obiect of workable proce drawn succe f und with a hiel r the wire, excessive se e other reason.

which wire may be ugh n series of dies at a high speed,

tension on the wire.

w're is under h such tension may be moinregardless of the speed at which the wire is drawn.

Another on z to provide a multiple die wire drawing machine having the foregoing properties and of the simplest construction eliminating the use of idling or jockey pulleys so that the wire is subjected to n minimum of bending und twisting as it passes through the machine.

additional Obie-ct or" the invention is to provide a multiple die wire draw fr machine provi with individuel pulling lo in which each pulling block is individt j! driven by a motor, 1out the motors are so connect that any desired torque relationship may be established between one motor another and the machine rnc-y be lcd up or slowed down without materially disturbing such torque relationship.

(ther objects and adviexplained or will be tion of the en which Figure l is a side elevation showing diagrainmatically the principal parts of a four die wire drawing machine 'on will e he following descripin the drawings, in

l 't rated rice and control panel therefor, constructed in accordance with my invention.

Figure 2 is a diagrammatic illustration of a detail of the machine in Fig. l showing how a die holder may be constructed and arranged to indicate the amount of pull on an individual die during operation of the machine.

Figure 3 is a wiring diagram showing a preferred munner oic conne field windings of the motors.

Figure #l is a wiring diagram showing all ofthe principal electrical connections for the wire drawing machine illustrated in Fig. l.

Figure 5 is a diagrammatic showing of a three die Inachine and its main electrical connections similar to the machine in Fig. l hut having its motor fields connected in f a d erentmunner.

accords ce wit. my invention, a multiple die wire in drawing machine is constructed with individual electric motors driving each cupstun or pulling hlocl., and the motors are electrically connected to and to the power supply so that the nechine may bc ed up at n slow or creeping speed while main ning a ce L .in torque relationship from one pulling block to smother, und whereby the machine after being i aded up cnn be brought up to operating speed without breaking the wire und while still in 'itaining the desir-cd torque relational between the oiierent pulling blocks.

have found that a V"chine constructs according to my preferred enibodi. lent can he operated at exceedingly high speeds, greatly above those coinrriercally available heretofore. Ye time the die friction and resultant die wear are rrl, the quality and y ol' the machine may even he operated at somewhat smaller total pou/ei consumption than has eeen required heretofore.

Figure l illustrates somewhat diagrammatically a preferred form of multiple die wire drawing machine constructed in accordance with my invention in which wire is successively pulled through a series of dies l, Z, 3 and 4 arranged in tandem. Capstans or pulling blocks 5, 6, 'l and 8 are also mounted on the bed 9 of the machine in a position to pull the wire straight through each of the dies, one such pulling clock being associated with each die. The pulling blocks are preferably individually driven 'oy the motors Mi, l, l2 and 13 through suitable reduc- 5 tion gearing such as a worm and worm wheel. It will oe observed in the machine illustrated in Figure l that the dies and blocks are mounted so that the wire leaving each die is pulled in a straight line from the die by its pulling block, and that the wire, after passing a suitable number of turns around such pulling block, is passed in a straight line to the entering side of the next die. Thus, the wire in passing through the entire machine moves in a straight path except for the turns or wraps of the wire about each of the pulling blocks. By arranging the blocks j and dies, except for the finishing block, in a tilted position, the machine may be constructed so that all of the blocks are at approximately the same heights above the licor level. lf desired, however, the same straight path for the wire may be achieved by mounting each successive die and pulling blockP at a higher level than the previous ones to form a series of steps and maintain the wire in a horizontal path of travel throughout the niachine.

A control panel 14 for the machine is preferably lo- 65 cated in a convenient position and provided with a nutrher of electrical or other indicators and controls. While not essential, one very desirable and convenient indicator for such a control panel is a die pull indicator, four of which are shown at l5, one being provided for each 70 Figure 2 illustrates diagramniatically one suitable i y in which these indicators and dies may be constructed and connected, although any suitable device may be used which indicates to the operator the amount of pull required at any given instant to pull the wire through the die. As illustrated, this device includes a die holder 16 pivotally mounted at 17, and carrying a suitable wire drawing die 18. The lower end of the die holder 16 preferably carries a block which bears against a torus or annulus 19 of hollow, flexible material such as rubber tubing lled with a suitable fluid such as oil. The annulus 19 is pressed by the die holder 16 against a portion of the frame 2t) as the wire 21 is pulled through the die 13. The indicator for the die may consist of any suitable type of pressure gauge such as a Bourdon tube arranged to operate an indicating needle or hand and connected by a small tube or pipe 22 to the interior of the annulus 19. Thus, as will be understood by those skilled in the art, the indicator 15 at any given moment registers with its needle the amount of pressure on the annulus 19 produced by the pull of the Wire Zt? on the die 153. The die holder indicators 15 may easily be calibrated to register die pull in pounds or other suitable units. For operating purposes, it may also be desirable to provide the faces of the indicators 1S with separate manually adjustable hands which can be moved to any given position.

Figure 4 illustrates the principal electrical connections for a machine constructed in accordance with my preferred embodiment. For reasons which will be explained, the motors 1i), 11, 12 and 13 are preferably D. C. motors, and have their armatures 23, 24, 25 and 26 connected in series to the power supply line 27. ln this manner, the current owing through the diiferent armatures is always the same in each motor.

An ammeter 2S may be connected in series with the armatures and conveniently located on the control panel 14 to indicate the amount of total current being used by the machine at any time. To facilitate starting and thread-- ing up the machine, a large bank of resistors or a large.

variable resistor 29 is preferably also connected in series with the motor armatures.

The resistance 29 may be provided with a control handle on the control panel 14, if desired, although I prefer to utilize controls on the machine itself. For example, a bar extending along the base of the machine may be so connected that the operator can adjust the resistance in series with the motor armatures, at least in part, from any position in front of the machine by simply pressing one of the foot treadles 29a. This makes it easier for one man to thread up the entire apparatus.

The main held windings 30, 31, 32 and 33 of the motors are preferably separately connected to the power lines 27, each such field winding being connected across or in parallel with the power lines, and each such held winding being connected in series with a pair of separatcly adjustable rheostats as indicated at 34, 35, 36 and 37, and at 34a, 35a, 36a and 37a, respectively. The first mentioned set of these individual iield rheostats may be mounted on the control panel 14 so that they can be adjusted by the handles 38, 39, dit and 41, respectively, and are arranged to be short circuited by closing the shunt switches 34]), 35h, 3611 and 37b, respectively. The second mentioned set of these individual field rheostats may be adjusted by operation of the control handles 34C, 35C. 36C and 37C, respectively, located in convenient positions on the machine itself.

In addition, a large or main rheostat 42 is preferably connected in series with all of the fields and the main power lines so that the iield strengths of all the motors may be adjusted simultaneously to alter the speed of the entire machine. This main speed regulating rheostat may also be mounted on the control panel and provided with an operating handle as shown at 43.

While not absolutely essential, it is most desirable in order to simplify operation of the machine as it is speeded up or slowed down, to design the individual motors so that the relative torque produced by each is substantially independent of the total load on the machine.

'i tains the wire under a substantial tension.

When the motor armatures are connected in series as shown at Fig. 4, this may be achieved easily by building into each motor a suitable small compound iield winding 64, in series with the armature, so that the eective eld strengths of the motors are substantially independent of the magnitude of the armature current.

If desired, ammeters 45, d6, 47 and d3 connected in series with each motors main held may be employed and calibrated to furnish an indication on the control panel 14 of the amount of torque developed by each motor in relation to the armature current shown by the ammeter 28.

In order to indicate the manner in which the total load of the machine is shared by the different motors, voltrneters 5u, 51, 52 and 53 may be connected across each armature and arranged to furnish this information ou the control panel. Some means is also very desirable to prevent excessive speed of one or more motors in the event the wire should break at any stage. For this purpose, any well-known form of over-voltage relay may be provided for interrupting the main power supply whenever the voltage across any one armature exceeds a safe value. The coils for such over-voltage relays are indicated across each armature at 54. If desired, the control panel (Fig. l) may also be equipped with any wellknown form of speed indicator showing the speed at which the wire is moving as it leaves the last die 4.

'fhis machine may be threaded up and operated as follows:

Before the machine is started, the resistance 29 is adjusted to a position in which resistance is all, or substantially all, in series with the motor armatures. The switches 34h, 35i), 36in and 37b are all closed thus short circuiting the rheostats 34, 35, 36 and 37. The control handles 34C, 35C, 36e and 37e are turned to a position such that the rheostats 34a, 35a, 36a and 37a are in open circuit position so that the circuits through the fields of all the motors are open. The rheostat 42 is adjusted to a position in which it does not introduce any resistance into the circuit.

The rod or wire to be drawn is now pointed, passed through die 1 and attached to the block 5 in the usual manner. The operator then presses on one of the foot treadles 29a to cut out some of the resistance 29 and turns handle 34C until the lirst block 5 begins to revolve slowly. After a sufficient number of turns or wraps of the wire have been built up on the pulling block 5, the handle 34C is turned back toward the starting position until the amount of the resistance 34a in the field circuit of motor 10 is such that the motor stalls but still main- The foot treadle 29a may then be released to increase the amount of resistance 29 in the armature circuit, and while the rst motor is in this stalled condition, the wire on the block 5 is secured firmly in place with a suitable clamp, wedge or similar device.

The end of the wire which is left free is then repointed, passed through die 2 and secured to pulling block 6 in the same manner as previously described. Foot treadle 29a is then again depressed, and control handle 35C is turned to close the field circuit of motor 11 and adjusted until pulling block 6 just starts to rotate. Pulling block 6 turns until the slack between die 2 and pulling block 5 is taken up, at which point the motor 11 is allowed to stall long enough to remove the clamp on pulling block S. The handle 35e is then turned still further to reduce the resistance in the field 31 of motor 11, until both the pulling blocks 5 and 6 begin to rotate slowly. They are allowed to rotate in this manner until a sufficient number of turns or wraps of wire are built up on pulling block 6 when the control handle 35C is backed off to the stalling condition for motors 1t) and 11. Foot treadle 29a is then released to increase resistance 29, md a clamp is again applied to the wire on pulling block 6.

The wire is again pointed and the same operation is performed to start the wire through dies 3 and 4 and arcane/ 1.

5 build up an adequate number of turns or wraps on the pulling blocks 7 and S. The end of the wire is firmly secured to the tinal or finishing block 3.

it will be apparent from the foregoing description that at this stage the pulling blocks 5, 6 and 7 do not exert sufficient pull to pull the wire through the preceding dies without the assistance of the torque applied by motor to the finishing block Thus, the wire between the pulling blocks 5, 6 and 7 and the dies 3 and d, respectively, is under a substantial amount oi tension. Fthis tension applies back tension on the wire entering these dies and at the same time exerts a forward pull to assist in driving the pulling locks 5, t and .7.

The machine is now ready to be brought up to operating speed. To accomplish this, the rheostats 29 and are adjusted or operated so that the resistance 29 in the armature circuit is reduced to zero and the resistance 4Z in the held circuit is increased to a point necessary to run the machine at the desired speed.

The rheostats 34, 3S, 36 and 37, which up to this time have been short circuited, are introduced into the held circuits after the machine has started to accelerate by opening the switches 34X), 351'), 36h and 37b. This may be done after the machine reaches its operating speed or at some point before it reaches such speed. The introduction of the rheostats 34, 35i, 36, and 37 into the motor ield circuits varies the amount of torque applied by each motor relative to the other motors depending upon the settings for these rheostats at the time the shunting switches are open.

lf the settings for these ield rheostats have not been predetermined, they may be manually adjusted by the operator after the machine is up to speed to produce the desired bach tensions on the wire on each of the dies E, 3 and 4. In making such adjustments, the operator is guided by the die pull indicators 15, which show a decrease in die pull as the back` tension is increased, and by the other instruments on the control panel.

On the other hand, if the desired settings of neit. rheostats are known for a particuiar operation, the controls 3S, 39, and 41 may be properly pre-set before the shunting switches Edil, 35h, 361'; and 37b are opened.

The manually adjustable hands on the die pull indicators 15, which were previously mentioned, may be adjustcd before the machine is threaded up, or during the process of threading up, to indicate the natural or normal amount of die pull at each die when the wire is being pulled through the die without any back tension on the wire entering the die. in this manner, the operator can determine readily the difference in the amount ot' die pull while the machine is operating with back tension on the wire by noting the relative positions of the xed manually adjustable hands and the indicating hands on the die pull indicators l5.

The connection of the armatures of the motors in series provides a speed control and permits a torque control which meets the particular needs of a multiple die non-slip continuous wire drawing machine. in such a machine, the pulling blocks are, in eifect, geared together by the wire so that the relative speeds of the motors are determined by the reduction in area of the wire at each die. With the series connected armatures, the individual motor speeds are completely self-adjusting to the die reductions, and the sum of the motor speeds can be controlled by rheostat 42.

The torques of the individual motors connected together in accordance with my invention may be separat ly adjusted as previously described to provide the desired heavy back tensions at the diiierent dies. Furthermore, once the relative torque adjustments are made, they remain substantially undisturbed by the operation of the machine at diierent speed levels.

These characteristics permit such a machine to be threaded up at very slow or creeping speed, and then brought up to operating speed without breaking the wire.

In fact, the motors may even be stalled during this operation. ln addition, this machine permits unusually wide variations in the percentage reductions that may be made in the wire at individual dies.

rl`he wire passing through the machine is also subjected to a minimum of bending and is tight at all points without any slack. This not only permits high operating speeds in the drawing operation, but also prevents circumferential slippage or" the wire on the drawing blocks with its attendant wear or scoring of the blocks. With no slippage oi the vire on the pulling blocks7 a larger than usual number of turns or wraps of the wire may be taken around each block, thus giving more opportunity to cool the wire between dies. The blocks may be cooled by water or air, or both, for this purpose.

By no slippage is meant no circumferential slippage of the wire around the blocks except for a negligible amount oi diagonal slip as the coil is pushed up the block by the oncoming wire, an amount which may be disregarded for all practical purposes.

Another advantage of a wire drawing machine constructed according to my invention is that it may be provided with a spooling device driven by a motor connected into the electrical circuits in a manner similar to the connection oi the motors driving the pulling blocks.

Figure 3 shows in its simplest form the parallel connection of three of the motor elds to the power supply 2.7. This involves the same type of circuit as illustrated in Fig. 4 in which separate rheostats 34, 3:5' and 36 are provided for each field and the main variable resistance or rheostat i2 is connected in series with all of the fields to enable the machine to be operated at very slow speeds or to be brought up to full operating speed without disturbing the individual torque relationship between the motors.

An alternative arrangement for connecting the motor iields is illustrated in Fig. 5, in which the dies l, Z and 3 are shown diagrammatically for drawing the wire 2li., the wire being pulled through the by the pulling blocks S, 6 and '7. Each pulling block is driven through reduction gearing lutz, lla and i261 by the individual motors whose armatures are indicated at 23, Ze and 2S. in this case, the armatures may be series connected as previously described in connection with Fig. 4. The motor iields d, d?. and 62, however, are shown as connected in series to the power supply 27, each field being provided with taps 63, so that the individual lield strengths of the motors can be adjusted separately to vary the field strengths of the motors and thereby the torque relationship of the motors. Here again, the main tield rheostat 42 is connected in series with the fields and power supply to adjust the operating speeds or" the motors simultaneously. This alternative arrangement of lield connections can be used, although l prefer to connect the iields in parallel as previously described since this avoids the necessity of using taps on the motor elds.

While resistors have been described as the means for controlling the armature and iield currents, especially for starting the machine, or applying stalled tension during threading up, it will be apparent to those skilled in the art that a similar result may be achieved by other variable voltage supply means such as grid controlled gaseous rectitiers or by a Ward Leonard type oi motor driven generator with field control.

The invention has been described in connection with an embodiment that involves the use of direct current motors, since motors of this type are easily designed and connected to provide the independent torque and speed adjustments which are necessary in the operation of my machine in order to produce satisfactory high speed drawing of the wire under considerable bacl; tension. lt is possible, however, to use alternating current motors provided they are so constructed and designed as to be capable of connection to each other and to the power supply, either directly, or through the use of transformers or other control equipment, to provide the necessary individual torque adjustability and to provide also the necessary speed adjustment without materially disturbing the torque relationship between them. Wound-rotor-in duction motors, for example, might be usedin place of the direct current motors which at this time I prefer.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modiiications are possible Within the scope of the invention claimed.

I claim:

A multiple die wire drawing machine comprising a plurality of dies and pulling blocks alternately arranged so that the wire passes directly lfrom a die to its pulling block and thence to the next die, separate direct current electrical motors for driving each block, said motors being constructed so that their iield strengths are substantially independent of their armature currents and being connected with their armatures in series and their elds in parallel with a power supply, rheostats connected to each motor eld circuit for varying the individual field strengths of the motors relative to each other, and means for increasing or decreasing the speeds of all motors simultaneously.

References Cited in the iile of this patent UNITED STATES PATENTS 851,823 Merrill Apr. 30, 1907 881,864 Lewin Mar. 10, 1908 1,281,439 Vicaire Oct. 15, 1918 1,803,676 Powell Mar. 5, 1931 1,914,833 Nachen June 20, 1933 2,138,126 Smith et al. Nov. 29, 1938 2,185,416 Morgan et al Jan. 2, 1940 2,263,246 Morgan Nov. 18, 1941 2,272,195 George Feb. 10, 1942 2,310,098 Lessmann Feb. 2, 1943 2,321,612 Nye June 15, 194 FOREIGN PATENTS 6,048 Great Britain Mar, 10, 1911 900,826 France July 10, 1945

Images