US2699864A

US2699864A - Wire-drawing machine

Info

Publication number: US2699864A
Application number: US41524A
Authority: US
Inventors: John H Hitchcock; Edmund S Murrah
Original assignee: Morgan Construction Co
Current assignee: Siemens Industry Inc
Priority date: 1948-07-30
Filing date: 1948-07-30
Publication date: 1955-01-18
Anticipated expiration: 1972-01-18

Description

Jan. 18, 1955 .1. H. HrrcHcoK ETAI- r2,699,891

WIRE-DRAWING MACHINE Filed July so, 1948 e sheets-sheet 1 By EDMUNO S. MunRAH 3 JOHN H. Hl'rcHcocx Jan. 18, 1955 J, H, HlTCHCOCK ET Al. 2,699,864

WIRE-DRAWING MACHINE K Acca LERAr/ow S TOP THREADJNG DRAWING (Z SECS.)

|700 a (G secs.)

TORQUE APPUED To BLOCKS IN FOOT POUNDS as a s 0 o o O Q C? voo-- ATTORNEY Jan. 18, 1955 J. H. HlTcl-lcocK ETAL 2,699,864

WIRE-DRAWING MACHINE I Filed'July 50, 1948 6 Sheets-Sheet 5 "I HII Ed. mhh

INVENTORS Jouw HHn'cHcocK BY EDMUND SMURRAH ATTQRNEY Jan. 18; 1955 .1. H. HITCHCOCK ET AL 2,699,864

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INVENTORS JOHN H. HITCHCOCK BY EDMUND 5. MURRAH ATTORNEY IIS RHI

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5 RHS United States Patent O WIRE-DRAWIN G MACHINE .lohn H. Hitchcock, Worcester, and Edmund S. Murrah, Shrewsbury, Mass., assignors to Morgan Construction Company, Worcester, Mass., a corporation of Massachusetts Application .l'uly 30, 1948, Serial No. 41,524

Claims. (Cl. 205-14) 'lhis invention relates to Wire-drawing machines, and more particularly to machines of the type having a series of dies through which the wire is drawn by means of rotating blocks or drums to effect successive reductions of the wire.

it has been recognized heretofore that certain important advantages would be obtained by maintaining an appreciable tension in the wire between each block and the succeeding die. Such so-called back pull will in general improve the quality of the wire, prolong the life of the dies by reducing the die friction and the resultant heat, and in many cases permit the drawing of the wire at higher speeds. There will often be a saving in power consumption. When back pull is applied to the wire approaching a particular die, there will necessarily be an increase in the forward pull in the wire leaving the die, but this increase in the forward pull will be less than the amount of the back pull. To obtain the maximum bcneiits from this type of wire-drawing, Ait is important to employ the highest practical back pull, the `theoretical limit being that at which the resultant increased forward pull approaches the breaking strength of the wire. Many prior attempts have been made to draw wire in this manner, but with very little success. The principal diiculty encountered has been frequent breakage of the wire, and because of this it has heretofore been found necessary to employ comparatively low back pulls, resulting in very little benefit,

lt is accordingly one object of the invention to provide a wire-drawing machine capable of operating `in a thoroughly dependable manner with comparatively high back pull on the wire.

it is a further object of the invention :to provide a multi-block machine for drawing wire through a series of dies and capable of operating satisfactorily with a comparatively high back pull between each block and the succeeding die without trouble from `wire breakage.l

With these and other objects in view, as will be `apparent to those skilled in the art, the invention resides in the combination of parts set forth -in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention and in which like reference numerals indicate like parts,

Fig. l is a top plan view of a multi-block Wire-drawin machine, partially broken away;

Fig. 2 is a front elevation of the machine, partially broken away;

Fig. 3 is a graph showing the variation in the torques applied to the several blocks under different phases of the operation;

Fig. 4 is a somewhat diagrammatic View, `largely in section, of certain valve mechanisms used for controlling the torque applied to the blocks;

Fig. 5 is a wiring diagram for the electrical apparatus used in connection with the machine;

Fig. 6 is a view similar to Fig. 1, but showing a modiiication of the invention;

Fig. 7 is a front elevation of the machine shown in Fig. 6, partially broken away;

Fig. 8 is an enlarged fragmentary view in section on the line @-8 of Fig. 7; and

Fig. 9 is a wiring diagram for the electrical apparatus used in connection with the machine shown in Figs. 6

The embodiment illustrated `in Figs. l and 2 comprises 2,699,864 Patented Jan. 18, 1955 a horizontally elongated hollow frame or casing 2Q which serves to support a series of live rotatable blocks 2l and a rotatable finishing block 22, the latter having the usual stripper Z3 thereon to support a bundle of finished wire and to facilitate its removal from the block. A suitable wire-drawing die 2li is mounted in advance of each block. To facilitate subsequent discussion of the machine, Fig. 1 has been marked with braces and the numerals from l to 6 inclusive to indicate the relative order of the six wire reduction stages, each of which includes one die and one lock. For example, we will later have occasion to mention the No. 1 die, or the No. 3 block, etc. The several blocks are all located on the top of the casing 2t) and they are all rotatable about vertical axes.

ln order to drive the blocks there is provided an electric motor 26 which is located at one end of the casing 2li and connected to a horizontal rotatable shaft 27, preferably made in several sections coupled to one another. This shaft carries a separate worm ZS (Fig. 1) for each of the blocks, each worm engaging a worm wheel 29 beheath each block. The worm wheel for the iinishing block 22 is secured directly to the vertical spindle 3l of the said clock so that it may be driven at a predetermined speed. The worm wheel for each of the blocks 21 is connected to the housing of a positive displacement rotary pump 32, as shown for example in the prior United States patent to Morgan et al. No. 2,l85,4l6 granted January 2, i940. As disclosed in said patent, each pump includes a rotor which is connected to the spindle of the associated block El. The casing provides a reservoir for oil, and the construction is such that each pump will draw a stream of oil from the reservoir and discharge it at a controlled pressure, thereby imposing a controlled torque on the pump rotor and on the block connected thereto. Each pump forms a hydraulic slip clutch which transmits torque to the corresponding block. The ratios of the several sets of worms and worm gears are such as to drive the pump housings at speeds somewhat higher than are required for the corresponding blocks, having in mind the particular wire drafting schedules to be performed by the machine. For purposes of control, as will be hereinafter explained, a small pilot generator 33 (Fig. l) is directly connected to the motor 26 and driven thereby.

When a machine of this type is to be placed in operation, it must first be threaded with wire. This involves pointing the wire, inserting the point through the No. l die, attaching the pointed wire to the No. l block by means of the usual grip while the driving motor 26 is stopped, driving the machine slowly until several wraps of wire are formed on the No. l block, and repeating this procedure for each of the remaining dies and blocks. When threading is completed, the machine must be accelerated to normal speed. After suiiicient Wire has accumulated on the finishing block 22, the machine must be stopped and a bundle of wire removed, whereupon the machine -vmust again be accelerated to normal speed. In a machine operating with back pull, the lvarious tensions throughout -the entire machine are inter-related. it is our belief that the difficulties heretofore encountered by reason of wire breakage 1n back pull machmes have been 1n very large part the result of failure to recognize the effect that the rotary inertia of the blocks has upon the wire tensions during rapid changes in speed. We propose to alter the driving torques applied to the respective blocks during acceleration or deceleration, with due regard to the rotary inertia of each block and to the speed of each block, in such a manner as to maintain the various wire tensions within allowable limits at all times. In order to make this matter clear, the invention will be explained in connection with a typical wire-drawing schedule. For this purpose we have chosen a schedulefor reducing steel rope wire of .80% to .90% carbon content from a diameter of .162 inch to a diameter of .063 inch in six drafts, the finishing speed being 1500 feet per minute. The back pulls set forth in the following Table A are those which experimental data indicate will result in forward pulls equal to of the breaking strength of the wire, this being as high as we consider it practical to go, having due regard to possible variations in the physical properties of the wire and in the numerous other factors involved.

Table A Stage No 1 2 3 4 5 6 Wire diam., inches-. .139 .119 .101 .086 .074 .063 Block diam., inohe 16 16 16 16 16 22 Block R.P.M 73.5 100.4 139 192.2 259.5 357.5 Tensile strength of wire, 1,000lbs./l.u.2 175 219.5 258.5 279 297 310 319 Breaking strength of wire,lbs 3,330 2,810 2,240 1,723 1,333 995 Forward ull without back pul,lbs 1,725 1,611 1,365 1,081 822 645 Forward pull with back pull, lbs 1,725 2,530 2,020 1,552 1,200 895 Back pull, lbs 1,530 1,110 S00 619 424 Die reaction with back pull, lbs 1,725 1,000 910 752 581 471 Tangential torce on block, s 195 1,420 1,220 933 776 895 Rotary inertia f block,

ibaft.z 108.6 108.6 108.6 106.1 106.1

, In the above table the die reaction with back pull is Vthe difference between the forward pull and the back pull, and it is a measure of the amount of friction and wear on the die. As indicated in the table, this die reaction is in all cases, except for the No. 1 die (which operates without back pull), very much less than the forward pull without back pull. It will also be noted that the tangential force on the block is appreciably less than the forward pull without back pull in all cases except No. 6 block, which has no back pull to help it rotate. The two values for the rotary inertia of No. 6 block correspond respectively to the bare block and to the block loaded with a 500 pound bundle of finished wire. From the tangential forces on the blocks, as set forth above, the torques which must be employed to drive the blocks in normal back pull drawing can be readily computed. For successful operation of the machine, however, it is necessary to alter the applied torques in accordance with the particular conditions existing at any given time. Thus in the first stage of threading a die, the corresponding block must receive sufficient torque to pull the wire through without having to overcome back pull, and in the second stage of threading (when the slack in the wire ahead of the die has been taken up) additional torque will be required to overcome the back pull. When the machine is accelerated or decelerat- Yed, it is of the greatest importance that the driving torque at each block be properly controlled with due regard to its rotary inertia and its normal speed in order to maintain the various wire tensions within allowable limits.

The following Table B has been prepared to show the values of the driving torques in foot pounds which are required for the several blocks under certain different phases of the operation, in order to maintain the same Wire tensions as those prevailing during normal wire It will be seen from the table that appreciable changes in torque are required for each block as the operation goes from one phase to another, and certain of these changes are very important for successful operation. For example, unless the required increased driving torque is applied to the blocks during acceleration, to overcome the rotary inertia of the blocks, the wire tensions throughout the machine will be increased, since the wire will compel all the blocksto accelerate simultaneously. However the `forward pulls on all the dies (except No. 1) have already been established at 90% of the theoretical breaking -strength of the wire, the 10% difference being considered the very minimum which can be tolerated if the operation is to be successful from a practical standpoint. Accordingly it will be apparent that any increase in the tension during acceleration will inevitably result in trouble from breakage of the Wire. However, decreases in tension durf ingY acceleration, so long as at least some back Vpull is maintained, can do no harm except for a loss of the full advantages of back pull during the few seconds required to bring the machine up to speed. Hence for the sake of dependability in operation we prefer to increase the torque applied to each block during acceleration to a value appreciably in excess of that set forth in the table as theoretically required to maintain the specified back pulls but nevertheless below the value required to draw wire without the assistance of any back pull. The amount of increase above the theoretical requirements is not critical. During stopping of the machine, the torque applied to each block should be decreased, and for simplicity of control we prefer to decrease the torque applied to each block during stopping by the same amount as the torque is increased during acceleration. By reasonable care in the selection of the amount of torque to be added and subtracted, the back pull at each die may be maintained somewhat lower, during both acceleration and stopping, than during normal drawing. The following Table C shows the particular torque changes which we propose to make for accelerating and stopping the machine in connection with the wire schedule under consideration, together with the resultant wire tensions throughout the machine. It will be noted that in all cases these tensions are below those encountered in normal drawing, and yet no slack can be produced, since an appreciable back pull is always maintained. The figures are based upon 6 seconds for acceleration and 2 seconds for stopping. The relatively short stopping time is considered desirable for reasons of safety, since any stop may be an emergency stop made necessary by someperson becoming caught in the machine.

Table C Stage No 1 2 3 4 5 6 Acceleration (6 seconds):

Theoretical torque to be added 4 6 8 11 15 Actual torque to be added 45 50 60 50 30 Drawing torque. 980 946 814 621 519 Total torque. 1, 025 996 874 671 549 Effective torque 1. 021 990 866 660 534 Tangential force on block 1, 531 1, 485 1, 299 990 801 Forward pull 952 735 Back pull 19 242 213 151 Die reaction 739 584 Stop (2 seconds):

Theoretical torque to be subtracted 12 18 24 33 45 Actual torque to be subtracted 45 50 60 50 30 Total torque 935 896 754 571 489 Effective torque 947 914 778 604 534 Taugential force on block 1, 420 1, 371 1,167 906 801 Forward pull-. 1, 794 1, 615 1, 345 1,090 816 Back pull 305 423 448 439 289 Die reaction 1, 489 1, 192 897 651 527 In Fig. 4 there is shown certain valve mechanism which serves to regulate the pressure of the oil discharged by one of the pumps 32 (say the No. 1 pump) and thereby control the torque applied to the corresponding block. It will be understood that a similar mechanism will be provided for each of the pumps. In the embodiment illustrateda pipe 35 leads from the discharge port of the pump not shown) to a chamber 36 in the lower portion of apressure regulating valve 37. An outlet port 39 leads downwardly from this chamber 36 to a pipe 40 through which the oil may return to the reservoir in the casing 20 (Fig. l). A gauge 41 is connected by a pipe 42 to the chamber 36 to indicate the pressure therein, this being a measure of the torque applied to the corresponding wire-drawing block. The ow through the outlet port 39 is controlled by a valve member 44 which is supported by a piston 45 thereabove, this piston being vertically slidable within a cylindrical bore 46 above and in communication with the chamber 36. 48 extends upwardly from the piston 45, and the lower portion of this rod is surrounded by a light coiled coinpression spring 49 which urges the piston downwardly. An orifice 50 is provided through the piston 45 so that a small stream of oil may flow upwardly therethrough fromthe chamber 36 to the interior of the bore 46 above the piston.

Oil from the interior of the bore 46 above the piston 45 is led through a pipe 52 to a manually adjustable pressure relief valve 53. This valve is provided with an inlet port 54 controlled by a spherical valve member 55,

A piston rod manner.

andan `outlet port 57` from which a pipe 58 may lead the Aoil back to `the reservoir. `The valve member 55 is urged toward its closed position by a coiled compression spring 59, and the force of this spring may be varied by a manually adjustable screw 60.

In the operation of the apparatus shown in Fig. 4, as so far described, oil discharged by the associated pump will Aiow through the pipe 35 to the chamber 36, and thence through the outlet port 39 and pipe 40 back to the reservoir. The pressure within the chamber 36, actring upon the lower surface of the piston 45, will hold the valve member 44 slightly above its seat to permit such ow. A relatively small continuous stream'of oil will `flow upwardly through the orice 50 into the upper portion of the bore 46 and thence through Vthe pipe 52 and `the relief valve 53. For a given setting of the adjusting screw 60 of the relief valve, the pressure within the chamber `36, will remain substantially constant despite varia- `tions lin the rate of ow through the pipe 35. This result -will be brought about by vertical movements of the piston 45 and the valve member 44 under the influence of the slightest variations in the pressure within the chamber, this pressure being opposed by the force of the` spring 49 andl by 4the pressure of the oil within the upper portion of the bore 46. If the pressure within the chamber 36 increases ever so slightly, the valve member 44 will be moved upwardly to relieve the excess pressure by Vpermitting increased flow through the outlet port 39. Similarly, the slightest decrease in pressure will cause downward movement of the valve member 44 to restore the desired pressure by decreasing the ow through the outlet port 39. By adjustment of the relief valve screw 60, the oil pressure above the piston 45 can be changed, and this will .cause the oil pressure in the chamber 36 to change as required to maintain the piston in a balanced or floating condition.

The relief valve 53 for each wire-drawing stage is adjusted so that the correct pressure will be maintained in the corresponding chamber 36 to provide the desired driving torque for the corresponding block during normal ldrawing of the wire. This adjustment will ordinarily not be changed unless the machine is to fbe used for a different wire-drawing schedule. However, as explained above, we propose `to make temporary changes in the driving torque when the machine `is to be threaded, accelerated, or stopped. For this purpose we provide cer- `tain additional apparatus, which will now be described.

As shown in Fig. 4, the `piston rod 48 carries a second piston 62 which slides within a cylindrical bore 63 in the upper portion of the valve 37, this bore being closed at its upper end by a plug 64 having a recess 65 therein to receive the upper end of the piston rod. A pipe 66 is connected to the recess 65` to lead oil therefrom back to the reservoir. By applying oil at suitable pressures to the upper or lower surfaces of the piston 62 during certain phases of the wire-drawing operation, the oil pressure within the chamber 36 may be changed to vary the torque' applied to the corresponding block in a desired For this purpose we provide a pressure reducing and regulating valve 68, a four-way valve 69, and a three-way valve 70.

The valve 68 is of a well-known type having a valve member controlled by a spring-loaded diaphragm, the latter being subjected to the fluid pressure at the discharge side of the valve. Such valves are adapted to maintain a substantially constant predetermined discharge pressure despite wide variations in the inlet pressure. One `suitable construction is disclosed in the United States patent to Temple No. Re. 19,545.

` The four-way valve 69 is of the solenoid-actuated spring-centered type. This valve is provided with a cylindrical bore 72, an inlet port 73 at the central portion of the bore, two

exhaust ports

74 and 75 adjacent the respective ends of the bore, and two

ports

77 and 78 communicating with the bore at points intermediate the inlet port 73 and the

respective exhaust ports

74 and 75. Pipes 79 may lead from the exhaust ports to the oil reservoir. A spool shaped valve member 81 is slidable within the bore 72 and is normally held in its central position, as shown, by two opposed coiled compression springs 82 located within the end portions of the bore. With the valve member in this position, any oil entering the inlet port 73 will be trapped within the valve spool, and both thQPOrts 77 and 78 will be connected through the bore 72 to the exhaust. 'Two solenoids AS1 and DS1 are connected to the opposite ends of the valve member 81. These parts are so arranged that if the solenoid AS1 is energized, the valve member will be moved to connect the inlet port 73 to the port 77, while the port 78 remains connected to exhaust. If on the other hand the solenoid DS1 is energized, the valve member will be moved in the opposite direction to connect the inlet port 73 to the port 78, while the port 77 is connected to exhaust.

The .three-way valve 70 is of the solenoid-actuated spring-return type. This valve is provided with a cylindrical bore 84, an inlet port 35, and two

control ports

86 and 87. The end portions of the bore are connected to pipes 90 which may lead to the oil reservoir. A spool shaped valve member 91 is slidable within the bore 84 `and is normally held at the left end thereof, as shown, by a coiled compression spring 92. With the valve member in this position, the inlet port 85 will be closed, and the port 86 will be connected through the bore 84 to the port 87. A solenoid JS1 is connected to the right end of the valve member 91, and when this solenoid is energized it will move the valve member to the right so that the inlet port 85 will be connected through the bore 84 to the port 87.

These various Valves are connected to one another by piping as follows. A pipe 94 leads from the pump discharge pipe 35 to the inlet of the pressure reducing valve 68, and a pipe 95 leads from the outlet of the valve 68 to the inlet port 73 of the valve 69. A pressure gauge 96 is connected to the pipe 95. A pipe 98 leads from the pipe 94 to the inlet port 85 of the valve 70. The port 77 of the valve 69 is connected to the port 86 of the valve 70 by a pipe 99. The port 87 of the valve 70 is connected to the upper portion of the bore 63 by a pipe 100. The port 78 of the Valve 69 is connected tothe lower portion ,of the bore 63 by a pipe 101.

These various parts are so constructed and arranged that when the No. l block is to be jogged during the threading of the No. l die. and the solenoid JSl is energized, oil from the pipe 35 may flow through the pipe 98, the port 85, lthe bore 84, the port 92 and the pipe 100 `to theupper end of the bore 63. This will urge the

pistons

62 and 45 downwardly, closing the valve member 44, and increasing the pump discharge pressure in the pipe 35 so that the pump may transmit ample torque for threading purposes. When the block is to be accelerated, with the solenoid .TS1 de-energized and the solenoid AS1 energized, the reduced `pressure within the pipe 95 will be transmitted through the port 73, the bore 72, the port 77, the pipe 99, the `port 86, the bore 84, the port 87, and ,the pipe 100 to the upper end of the bore 63. This will urge the piston 62 downwardly and increase the pressure within the pipe 35 required to maintain ilow through the port 39, thereby increasing the torque which the pump will normally transmit by an amount determined by the adjustment of the pressure reducing valve 68. When the block is to be decelerated to stop the machine, the solenoid DS1 will be energized so that the reduced Vpressure within the pipe 95 will be transmitted through the port 73, the bore 72, the port 78, and the pipe 101 to the lower end of the bore 48. This will urge the piston 62 upwardly and decrease the pressure within the pipe 35 required to maintainow through the port 39. This will decrease the torque which the pump will normally transmit by an amount determined by the adjustment of the pressure reducing valve 68. Since the effective areas of theupper and lower surfaces of the piston 62 are equal, the torque added for acceleration will be equal to the torque subtracted for deceleration. During normal running at a substantially constant speed, with the three solenoids de-energized, both ends of the bore 63 will be connected to the exhaust pipes 79 through the intervenmg pipes and valves. Under these conditions `the torque transmitted by the pump will be controlled by the adjustment of the relief Valve 53.

It will be understood that a pressure control apparatus as shown in Fig. 4 will be required for each of the pumps 32. For the purpose of description, the five jogging solenoids will be designated TS1 to JSS inclusive. Similarly the iive accelerating solenoids will be designated AS1 to ASS inclusive, and the tive decelerating solenoids will be designatedl DS1 to DSS inclusive. These various solenoids all appear in the wiring diagram of Fig. 5, which will now be described.

l'n Fig. 5 there is illustrated diagrammatically `certain electrical apparatus whereby the `machine may be oper- Vpush button switch 113.

ated in a desired manner. This includes `a source 103 of constant voltage direct current controlled by a main switch 104. The motor 26 is provided with a commutating field 105 and a main ield 106. The pilot generator 33 is provided with a field 107. Two

rheostats

109 and 110 are provided, these being mechanically connected for simultaneous adjustment. A line contactor A includes a normally open switch A1 and a normally closed switch A2. A run contactor B includes normally open 'switches B1, B2, B3, B4, and B5, and normally closed switches B6 and B7. A dynamic brake contactor C includes a normally open switch C1. An accelerating contactor D includes a normally open switch D1 and a vnormally closed switch D2, while a second accelerating contactor E includes a normally open switch E1 and a normally closed switch E2. A decelerating contactor F includes a normally open switch F1. A field accelerating relay G includes a normally open switch G1. A full vfield relay H of the time delay type (as indicated normally closed switch M1. A normally closed stop push button switch 112 is provided, and a normally open run For jogging block No. l, a pair of interconnected normally open push button switches 114 and 115 are provided. Similar pairs of

switches

116 and 117 are provided for jogging No. 2 block, together with

switches

118 and 119 for No. 3 block, switches 120 and 121 for No. 4 block, switches 122 and 123 for No. 5 block, and a single normally open switch 124 for No. 6 block. A resistance 125 is provided to aid in obtaining the desired control of the motor 26.

The electrical connections for the various switches and other devices as shown in Fig. will now be described. The switch A1, the armature of the motor 26, the comrmutating field 105, the switches E1 and D1, and the field accelerating relay G are connected in series across the main switch 104. The switch C1 and a portion of the resistance 125 are connected in series across the armature 26 and the field 105. A second portion of the resistance 125 is connected across the switch E1, and a third portion is connected across the switch D1. The field 106 and the rheostat 109 are connected in series across the main switch 104. Each of the switches G1 and -H1 is connected across the rheostat 109. The

switches

112 and 113 and the run contactor B are connected in series across the main switch 104. The switch B1 is connected across the switch 113. The switch B2 and the line contactor A are connected in series across the main switch 104. Each of the

switches

114, 116, 118, 120, 122

and 124 is connected across the switch B2. The switch B3, the accelerating contactor D, and the switch J1 are connected inV series across the main switch 104.

VThe accelerating contactor E and the switch K1 are connected in series across the contactor D. The VVfollowing groups of devices are each connected 1n series across the vmain switch y104; the switch B6 and the accelerating relay I; the accelerating relay K and the switch D2; the

`full field relay H and the switch E2; the switch A2 and theV dynamic brake contactor C; the switch 115 and the jog solenoid ISI; the switch 117 and the jog solenoid JS2; the switch 119 and the jog solenoid JS3; the switch 121V and the jog solenoid JS4; the switch 123 and the jog solenoid ISS; and the switch B4, the switch M1,

the switch L1, and the decelerating contactor F; and

the switch F1 and the decelerating solenoid DS1, the remaining decelerating solenoids DS2 to DSS inclusive being connected across the solenoid DS1.

The operation of the embodiment illustrated in Figs. l to 5 inclusive will now be apparent from the above disclosure. Assuming that the main switch 104 is closed,

[the `cantautor C andthe relays H,v J and K will be energized. Hence switches C1' and H1 will be closed, while switches .l1 and K1 are open. To thread the No. 1 die, the No. 1 Vblock may be jogged by pressing the No. l jog button to close the switches 114 and 115. Closing the switch 114 will energize the line contactor A, closing the switch A1 and opening the switch A2, de-energizing the dynamic brake contactor C, and opening the switch C1. As the switch A1 closes, the motor 26 will start and operate at slow speed, since the full field 106 is applied by the closed switch H1, and the portions of the resistance 125 controlled by the switches E1 and D1 are in series with the motor armature. The closed switch will energize the solenoid JS1, so that the No. l pump will transmit the necessary torque Vto the No. l block for threading purposes. When the desired number of wraps of wire have been wound on theblock, the jog button will be released, opening the switches 114 and 115. This will de-energize the line contactor A, open the switch A1, close the switch A2, energize'the brake contactor C, close the switch C1, and cause the motor 26 to stop by dynamic braking byv inserting -a portion of the resistance across the motor. The remaining blocks may be jogged successively in a similar manner by pressing the corresponding jog buttons, until the machine is fully threaded. Since the No. 6 block has no corresponding pump or jogging solenoid, its jog button includes only the single switch 124. It will be noted that while any of dies Nos. 2 to 6 are being threaded, the preceding blocks will need only Vnormal running torque, for by the time the wire has tightened around these blocks sufficiently to give capstan effect thereto, the back tension will be available to assist in their rotation, as will be apparent from Fig. 3.

Upon completion of the threading, the machine will be ready to run, and the operator need merely press the run button to close'the switch 113 momentarily, thus energizing the run contactor B, so that switches B1 to B5 inclusive will close, and switches B6 and B7 will open. The closed switch B1 will maintain energization of the contactor coil B. The closed switch B2 will energize the line contactor A to start the motor 26 at slow speed. The closed switch B4 will energize all the accelerating solenoids AS1 to ASS inclusive, so that all of the pumps 32 will transmit the proper accelerating torques to their respective blocks to overcome the rotary inertia thereof. The amount of torque to be` added to the normal running torque will be determined in each case by the adjustment of the corresponding pressure reducing and regulating valve 68 (Fig. 4). As the switch B6 opens it will de-energize the accelerating relay I, and as this relay times out the switch I1 will close, energizing the accelerating contactor D. The switch D1 will thereupon close, shunting the corresponding portion of the resistance 125, and increasing the motor speed. The switch D2 will open, deenergizing the accelerating relay K. As this relay times out 'the switch K1 will close, energizing the accelerating contactor E. The switch E1 will close, shunting the corresponding portion of the resistance 125, and the motor will accelerate to its basic speed. At the same time the switch E2 will open, deenergizing the full field relay H. As this relay' times out, the switch H1 will open, rendering the rheostat 109 effective to reduce the strength of the motor field 106 and causing the motor to accelerate to its present speed as determined by the adjustment of the rheostat. During this phase of the operation the relay G will control the rate of acceleration. If this rate exceeds a predetermined value, the armature current will become sufiicient to cause the relay to pick up, closing the switch G1, shunting .the field rheostat 109, and increasing the strength of the field 106. This will reduce the armature current and cause the relay G to drop out. This relay will continue to pick up and drop out momentarily until the motor has reached its preset speed. At this Ytime the pilot generator 33, which is driven by the motor 26, will reach sufficient speed to supply the voltage required to pick up the accelerating relay M, thus opening the switch M1 and de-energizng the accelerating solenoids AS1 to ASS inclusive. This will cause the pumps 32 to transmit the normal running torques to their respective blocks as determined by the adjustments of the corresponding pressure relief valves 53 (Fig. 4). Thus the machine will continue to operate with predetermined back-tensions throughout.

When a sutiicient quantity of wire has accumulated on the finishing block 22, the operator will stop the machine and remove a bundle of wire. The machine may be stopped by merely pressing the stop button to open the switch 112 momentarily. This will de-energize the run contactor B, opening the switches B1 to B5 inclusive, and closing the switches B6 and B7. As the switch B2 opens, it will cie-energize the line contactor A, the switch A1 will open, and the switch A2 will close, energizing the brake contactor C and closing the switch C1. This will cause the motor 26 to stop very quickly by dynamic braking. As the switch B7 closes it will energize the decelerating contactor F and closethe switch F1, thereby energizing all of the decelerating solenoids DS1 to DSS inclusive.` This will reduce the torque applied by the several pumps 32 to the respective blocks and cause all of the blocks to decelerate in step with the motor 26. As the switch B opens, it will de-energize the decelerating relay L, and this relay will time out shortly after the machine has come to a stop. The switch L1 wiil then open, de-energizing the decelerating contactor F, opening the switch F1, and de-energizing the decelerating sole noids DS1 to DSS.

There are important advantages in positively gearing the No. 6 block (rather than one of the preceding blocks) to the motor 26. f the positive drive were applied to one of the first five blocks, it would be necessary to apply a controlled torque to the No. 6 block, and to vary this torque (during acceleration and deceleration) in accordance with changes in the rotary inertia of the block, which varies widely in accordance with the amount of finished wire accumulated on the block. Furthermore, in starting the machine, the positively driven block would tend to start an instant ahead of the hydraulically driven blocks, and this might create sufficient slack in the wire leaving the positively driven block to cause a momentary loss of capstan effect on this block. As soon as the following blocks had taken up this slack, the capstan effect would be restored very suddenly, producing a heavy jerk on `the wire immediately anterior to the positively driven block, with probable breakage of the Wire. A further advantage of our preferred construction is that the deliv ery speed of the finished wire is directly determined by the speed of the motor 26, which can be changed by adjustment of the field rheostat 199. Such adjustment effects a corresponding adjustment in the rheostat 110, so that the relay M will always pick up at the proper motor s eed.

pIt will be apparent that the invention provides a thoroughly dependable multiblock wire-drawing machine which can be operated with a comparatively high back pull on the wire. The breakage of wire and the production of slack wire during acceleration or deceleration of the machine is substantially eliminated, and an accurate control` of the wire tensions throughout the machine is obtained.

In Figs. 6 to 9 inclusive there is shown a modification of the invention, certain of the reference numerals of Fig. 1 being utilized when applicable. Thus there is provided the frame or casing 20, the five blocks 21, the finishing block 22 with its stripper 23, and the six dies 24. The machine is driven by the electric motor 26, to Vwhich the small pilot generator 33 is directly connected.

In this embodiment each of the six blocks is mounted on the upper end of a vertical rotatable spindle 130 to which a worm gear 131 is fixed. The gear 131 for each of the first five blocks 21 meshes with a separate horizontal worm 132, while the gear 131 for the finishing block 22 meshes with a horizontal worm 133. The motor 26 drives a horizontal shaft 135 which is supported in suitable bearings 136. This shaft is` preferably made in several sections coupled to one another. The worm 133 for the finishing block 22 is secured directly to the shaft 135 to provide a positive drive for this block. Each of the worms 132 for the blocks 21, however, is of hollow construction, as shown in Fig. 8, so that the shaft 135 may pass axially therethrough, these worms being rotatably mounted in suitable bearings 137.

Means is provided to transmit a predetermined controlled torque from the shaft 135 to each of the worms 132. For this purpose each Worm 132 is connected at 80 one end to the driven member 139 of a suitable magnetic slip clutch 144i (Fig. 8), which may be of the wellknown eddy current type. Each of these five clutches in- ,cludes a driving member 141 fixed to the shaft 135 and carrying an energizing coil, these coils being identified as ECI to EC5 inclusive `to correspond with the respective blocks. Electric current is transmitted to each Coil fin known manner through a pair of brushes 143 which engage a pair of slip rings 144 carried by the shaft 135, the ends of the coil being connected to the slip rings. The rings are of course insulated from the shaft and from one another. The torque transmitted by each clutch 140 will depend upon the extent to which its coil is energized, and the speed ratios of the several sets of worm gears will be such that each of the worms 132 will rotate at a somewhat lower speed than the shaft 135 when carrying out the particular wire drafting schedules for which the machine is adapted. Thus in normal continuous wire drawing there will be some slippage in each clutch.

In Fig. 9 the control mechanism for the motor 26 and for the several magnetic clutches is shown diagrammatically. Many parts of this mechanism are the same as in Fig. 5, and the same reference symbols have been employed wherever applicable. Thus there is an electric power source 103 and a main switch 104. The motor 26 has a commutating field 105 and a main field 1116. The pilot generator 33 has a field `107. Two mechanically connected rheostats 169 and 110 are provided. There is a stop push button 112 and a run push button l113. Push button switches 114 to 124 are provided for jogging purposes. There is provided a line contactor A, a run contactor B (from which the switch B7 of Fig. 5 has been omitted), a dynamic brake contacter C, two accelerating contactors D and E, and a motor control resistance 125. Further provided is a field accelerating relay G, a full eld relay H, two accelerating time delay relays I and K, and an accelerating relay M. There is also provided further apparatus (not required in Fig. 5) including two torque increasing relays N and O, two torque decreasing relays P and Q, five torque control rheostatsRHl to RHS inclusive, and five torque control resistances RE1 to RES inclusive. The relay N includes sii.Y normally open switches N1 to N6 inclusive, the relay 0 includes ve normally open switches O1 to G5 inclusive, the relay P includes six normally open switches P1 to P6 inclusive, and the relay Q includes five normally open switches Q1 to Q5 inclusive. Each of the relaysG and Q is of the time delay type, as indicated by the letters td adjacent thereto.

The electrical connections between the `various parts in the upper portion of Fig. 9 are similar to the corresponding connections in Fig. 5, and it is considered unnecessary to repeat the description here. This applies to the connections for the motor 26, the pilot generator 33, the stop button 112, the run button 113, the rheostats 109 and 11i), the contactors A, B (except switches B4 and B5), C, D, and E, and the relays G, H, J and K. in addition, the following series circuits are provided across the main switch 1114: the switch Bai, `the switch M1, and the relay 'Ng the switch N6 and the relay O; the switch B5 and the relay P; the switch P6 and Vthe relay Q; the rheostat RH1,`the resistance REI, aud the clutch coil EC1; the rheostat RHZ, the resistance REZ, and the clutch coil EC2; the rheostat Ril-i3, the resistance RES, and the` clutch coil EC3; the rheostat Iii-14, the resistance RE4, and the clutch coil ECd; and the Arheostat RHS, the resistance RES, and the clutch coil ECS. The

push button switches

11d, 116, 11S, 121i, and 122 are connected across the resistances REI, REZ, RE3, RFA, and RES respectively. Each of the push button switches 115, 117, 119, 121, 123, and iiis connected across the switch B2. Each of the switches N1, O1, P1 and Q1 'is connected across a different portion of the resistance REL leaving a fifth portion thereof unshunted. The other resistances REZ to RES inclusive lare similarly controlled by the correspondingly numbered switches of the relays N, O, P and Q.

In the operation of the embodiment shown in Figs. 6 to 9 inclusive, with the main switch 1114 closed, the No. 1 block may be jogged for threading purposes by pressing the No. 1 jog button to close the switches 114 and 115. The closed switch will energize the line contacter A and cause the motor 26 to run at a slow speed, as already described in connection with the previous embodiment. The .closed switch 114 will short out the entire resistance RE1 and `provide sufficient energization to the clutch coil ECI to afford the transmission of ample torque to the No. 1 block for threading purposes. The remaining blocks may be jogged in a similar manner until the machine has been completely threaded. The run button 113 will then be pressed, energizing the run contactor B and causing the motor 26 to accelerate in the same manner as in the previous embodiment. The closed switch B4 will energize the relay N, and the closed switch B5 will energize the relay P. As the switch N6 closes it 5 will energize the relay O, and as the switch P6 closes it will energize the relay Q. Thus all the switches for the relays N, O, P and Q will be closed, and the corresponding portions of the resistances REI to RES inclusive will be shunted. With the various resistances properly adjusted this will provide the correct energization for the several clutch coils to give the proper torque for acceleration of the corresponding blocks. As the motor 26 and the pilot generator 33 reach normal running speed, the

relay M will pick up, opening its switch M1 and breaking l5 the circuit to the relay N. As this relay drops out, all the N switches will open, and the circuit to the relay O will be broken. As this relay times out, all the O switches will open. Thus additional portions of the resistances RE1 to RES will be rendered effective in two successive 20 steps to reduce the excitation of the corresponding clutch coils and to reduce the torques at the corresponding blocks to the normal running values.

To stop the machine it is merely necessary to press the stop button 112. This will de-energize the run con- As the switch B5 opens, the relay P 30 times out all the Q switches will open, rendering still further portions of the RE resistances effective to reduce the current flow through the EC coils. Thus with the various resistances properly adjusted, the torques applied by the clutches 140 to the blocks Nos. l to 5 will be decreased sufiiciently to cause these blocks to decelerate in 40 step with the motor 26 without creating slack or excessive tension in the wire at any point.

It will be apparent that the invention provides a new and highly advantageous construction for a multi-block wire-drawing machine. The wire tensions throughout the machine are held at desired values at all times, and the torque applied to the blocks during changes in speed 1s so altered as to minimize the danger of wire breakage. While two embodiments of the invention have been illustrated, other embodiments may occur to those skilled in the art in the light of our disclosure and within the scope of our claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A driving and control apparatus for a continuous wire-drawing machine having a plurality of rotatable drums and having dies situated between said drums, said apparatus comprising a driven shaft adjacent each drum, a variable torque transmission connecting each drum except one to its driven shaft, a starter mechanism for initiating the motion of the machine, a stopping mechanism for initiating the stoppage of the machine, a rst control device connected to each said transmission and maintaining a constant, predetermined torque transmittal to its respective drum during normal running operation of the machine, a second control device connected to each said transmission device and to said starter mechanism for causing the torque transmission to increase substantially upon actuation of said starter mechanism, a third control device connected to each said transmission device and to said stopping mechanism for causing the torque itransmission thereof to decrease substantially upon actua- Y tion of said stopping mechanism, the said one drum being directly connected to its drive shaft to control the speed chine, a stopping mechanism for initiating the stoppage of the machine, a first control device connected to each clutch and maintaining a constant, pre-determined torque transmission to its respective drum during normal running operation of the machine, a second control device connected to each said clutch and to said starter mechanism for causing the torque transmission to increase substantially upon actuation of said starter mechanism, a third control device connected to each said clutch and to said stopping mechanism for causing the torque transmission thereof to decrease substantially upon actuation of said stopping mechanism, the said one drum being directly connected to its drive shaft to control the speed of theV machine, the said increase and decrease in torque transmission being of values so related to the rotary inertia of the respective drum as to maintain wire tension below the breaking strength of the wire.

3. A driving and control apparatus for a continuous wire-drawing machine having a plurality of rotatable drums and having dies situated between said drums, said apparatus comprising a driven shaft adjacent each drum, a hydraulic clutch having variable torque transmission characteristics connecting each drum except one to its driven shaft, a starter mechanism for initiating the motion of the machine, a stopping mechanism for initiating the stoppage of the machine, a lirst control device connected to each said clutch and maintaining a. constant, predetermined torque'transmittal to its respective drum during normal running operation of the machine, a second control device connected to each said clutch and to said starter mechanism for causing the torque transmission to increase substantially upon actuation of said starter mechanism, a third control device connected to each said clutch and to said stopping mechanism for causing the torque transmission thereof to decrease substantially upon actuation of said stopping mechanism, the said one drum being directly connected to its drive shaft to control the speed of the machine, the said increase and decrease in torque transmission being of values so related to the rotary inertia of the respective drum as to maintain wire tension below the breaking strength of the wire.

4. A driving and control apparatus for a continuous wire-drawing machine having a plurality of rotatable drums and having dies situated between said drums, said apparatus comprising a motor and a drive shaft driven by the motor, a magnetic clutch having variable torqueV characteristics connecting each drum except one to the drive shaft, a starter switch mechanism for initiating the motion of the machine by impressing current on said motor and impressing a separate pre-determined current on each clutch, stopping switch mechanism for initiating the stoppage of the machine by removing the current from said motor, a iirst control device connected to each clutch and maintaining the said pre-determined current at a constant value during normal running operation of the machine, a second control device connected to each said clutch and to said starter mechanism for causing the current to the clutch to increase substantially upon actuation of said starter mechanism, a third control device connected to each said clutch and said stopping mechanism for causing the current in the clutch to decrease substantially upon actuation of said stopping mechanism, the said one drum being directly connected to the drive shaft to control the speed of the machine, the said in- 5 crease and decrease in current causing a corresponding of the machine, the said increase and decrease in torque.n

transmission being of values so related to the rotary in-c4 ertia of the respective drum as to maintain wire tension below the breaking strength of the wn'e.

2. A driving and control apparatus for a continuous wire-drawing machine having a plurality of rotatable drums and having dies situated between said drums, saidstartermechanism for initiating the motion of the ma--j' change in torque transmission by said clutch of values so related to the rotary inertia of the respective drum as to maintain wire tension below the breaking strength of the wire.

5. A driving and control apparatus for a continuous wire-drawing machine having a plurality of rotatable drums and having dies situated between said drums, said apparatus comprising a motor and a drive shaft driven by the motor, a hydraulic clutch having variable torque transmission characteristics connecting each drum except one to its driven shaft, a starter mechanism for initiating the motion of the machine by impressing current on the motor and impressing a separate pre-determined hydraulic pressure on each clutch, stopping mechanism for initiating the stoppage of the machine by removing the current from said motor, a first control device connected to each clutch and maintaining the said pre-determined pressure at a constant value during normal running operation of the machine, a second control device connected to each said clutch and to said starter mechanism for causing the pressure on the clutch to increase substantially upon actuation of said starter mechanism, a third control device connected to each said clutch and to said stopping mechanism for causing the pressure in the clutch to decrease substantially upon actuation of said stopping mechanism, the said one drum being directly connected to the drive shaft to control the speed of the machine, the said increase and decrease in pressure causing a corresponding change in torque transmission by said clutch of values so related to the rotary inertia of the respective drum as to maintain Wire tension below the breaking strength of the wire.

References Cited in the file of this patent UNITED STATES PATENTS Morgan Jan. 2, Mueller Oct. 29, Parvin Apr. l, Parvin May 20, Burt June 17, Morgan Nov. 18, Bowman Nov. 9, Fath June 28,