US2272187A - Wire drawing machine - Google Patents

Description

Feb. 10, 1942. F. P. DAHLSTR'OM 8 WIRE DRAWING MACHINE Filed July 24, 1940 s Sheets-Sheet 1 INVENTOR. fkA VK RDAHLSTIQO/Y I rokzve Y5.

4 Feb. 10, 1942.

F. P. DAHLSTROM WIRE DRAWING- MACHINE Filed July 24, 1940 3 Sheets-Sheet 2 INVENTOR. F4Nlf 2 m zsreom OENEYS.

Feb. 10, 1942. F. P. DAHLSTROM WIRE DRAWING MACHI NE Filed July 24, 19 40 3 Sheets-Sheet 5 INVENTOR. FFA/VK P. oAHzsrkon Patented Feb. 10, 1942 UNITED. STATES; PATEN T OFFICE.

- WIRE DRAWING MACHINE Frank P. Dahlstroni, Woodbridge, Conm, assignor to The Aetna-Standard Engineering Company, Youngstown, Ohio, a corporation of Ohio Application July 24, 1940, Serial No. 347,259 I I 12 Claims.

pensate approximately for the elongation of the' In the machine of wire in the successive drafts.

tionof the machine shown in Fig. 1.

the Connor patent the drums are arranged to permit an accumulation of wire thereon to allow steady operation of the machine for some time,

even though the speeds of the various drums are not in exact proportion to the elongation of the wire. It has been proposed, as disclosed in the application of Jerome R. George and Kenneth B. Lewis, Serial No. 281,666, filed June 28, 1939, to provide individual electric motor drives for the various blocks or drums in machines of the 'Connor type whereby the operator of the machine can control the speeds of the individual drums so that the machine can' be regulated to maintain substantially constant accumulations .which is simple anieiiective'and substantially x Furthenobjeetsand advantages of my inyention wfllbecome'apparentfrom the folfoolproof.

lowing description 01f I a a preferred form thereof,

reference being made to the accompanyingdraw ings. The essential. characteristicsare set forth in-the claims. Referring to the bodying my inventionand including three dies and associated blocks. Fig. 2 is a. front eleva- I I Fig. 3 is a sectional detail taken along the line of 33 in Fig. 1 but with the block rotated through 90"for. convenience of illustration. Fig. 4 is a detail of part of the automatic control mechanism shown in Fig. 3, as indicated by the line of wire on the various drums, with the result that I the machines can be operated continuously for definitely long periods of time without the necessity of running ofi the wire on the blocks .and rethreading the machine at requent intervals, as is required by the original Connor type of machine. I

It is a general object of the present invention to provide acontinuous'wire drawing machine constituting a further improvement on machines 4-4 of Fig. 3, and Fig. 5 is a diagram of the electric circuits for the automatic control.

The machine illustrated in Figs. 1 and 2 may be of the general type described and claimed in I I my copending application Serial No. 285,338, filed July 19, 1939, and maybe built up by assembling a numberof generally similar. units l0,

II and I2, each unit being provided with die boxes indicated at l4, l5 and I6 for supporting suitable wire drawing dies Ma, Ma and Ilia, and I the units embodying blocks or drums I 8, I9 and 20, respectively. The blocks or drums preferably are driven by independent variable speed . motors 22, 23 and 24 through any convenient gearing or. power; transmitting mechanism such as that illustrated in my aforesaid application. Inasmuch as this mechanism and the mode of supporting the blocks on the frames of the vunits form, per se, no part of the present invention,

' no further description of these parts of the appaof the type illustrated for example in the Connor patent and in which automatic means are provided forcontrolling the speed of the various I drums. of the machine so that the machine will be operated in such fashion that substantially equal weights of wire will be drawn through the dies associated with each block or unit for any given period of time. By this arrangement the accumulations of the wire on the blocks of the machine (except for the finishingblock) remain substantially constant and the machine can be operated continuously-with a minimum amount of attention being required.

Another object of my invention is to provide a simple and effective mechanism for -'automatically controlling the speed of the blocks of wire drawing machines. Afurtherobject is to provide an automatic control mechanism;

ratus will be given in the present specification.

The units are arrangedin line as shown in Figs. 1 and 2, the wire W being drawn through the die bo-x l4 and its associated die Ma onto the drum'or block I8 where it is wrapped tightly around the portion 26, As more wire is drawn on to the block, the coils are moved upwardly,

surrounding the'reduced portion 21. In thread-I ing the machine, a considerable number of turns of wire are accumulated'on the block, so' as to permit the wire to cool and rest between' successive drafts. The 'wire'is taken off the block in a enerally axialdirection over the sheave 28 f I Carried y an arm 29 .which is mounted fo'r'r'ota-" tion about an axis aligned with the axis of the block 18 in a manner to be described in detail below. "The wire is then carried upwardly and guided over the pulley 32 'disp'osedabove thedrawings, Fig. 1 illustrates a top plan view of a wire drawing machine em;

center of the drum l8, thence downwardly and around the pulley or sheave 33 to the die box l where it is drawn through another die on to the drum or block H of substantially identical construction with the block is. v

The wire is led away from the block IS in the same manner as from the block l8, that is, it is carried over the pulley 34 supported by the arm 35, over pulleys 3G and 3! to the die-box l8 and its associated die. The wire is drawn through the die box it and die lilo on to the finishing drum or block'lll which is of slightly different construction, in that it is provided with axially extending bars 38 for retaining a coil of wire of considerable size on the drum, the bars and coil being protected by a wire guard 35. The finishing unit is also preferably provided with an upwardly extending arm or bracket All adapted to support a hoist for removing the coil of wire from the finishing block.

In general, the three units may be of substantially identical construction so far as the supporting frames and driving mechanisms are concerned, The motors of units l6 and H are controlled by motor-driven rheostats M and 42, while a manually-operated rheostat 43 is provided for controlling thespeed of the motor 2%,

around in a clockwise direction. On the other I hand if the wire is being removed from the block Different gear ratios may be employed within the units as the drum of each succeeding unit must be operated at a higher rate of speed than the speed of the preceding unit due to the reduction and corresponding elongation of the wire as it passes through each succeeding die. The die box on the first unit ill is arranged slightly difierently than the'die box on the remaining units and the finishing unit employs a block or drum of somewhat different character and the guide pulleys are eliminated. from the finishing block. Generally speaking, however, the units preferably are of substantially identical construction, and as those skilled in the art will understand, it is not necessary to employ precisely three blocks or units, but the invention is useful in cornunction'with a machine embodying only two blocks, as well. as with a machine embodying more than three blocks. Further, the blocks need not be mounted on separate units, but may all he supported on a single bench or frame.

it is a characteristic of machines of this type that so long as wire is being removed from a blockat the same rate at which it is being drawn on to the block, then the guide over which the wire is withdrawn from the block will remain stationary. That is, for example, if the relationship between the speeds of the blocks is and Eli and the diameters of the wire after it has been drawn through the dies Mo and Etc are such that the same weight of wire is drawn through both dies per unit of time, then the wire will be drawn on to the block it at precisely the same speed at which it leaves the block it over the sheave 28. Thus the same number of turns of wire will remain on the block ill, and the bracket 29 and the pulley 28 will remain stationary with respect to the central axis of the block.

If wire is being withdrawn from the block faster than it is being supplied thereto, then the number of turns of wire on the block. will be reduced and the bracket 29' and pulley 28 will rotate around the central'axis of the block in a direction opposite to the rotation of the block, that is, in the drawings the block it? is driven in a counter-clockwise direction and under these circumstances the guide pulley 28 will swing at a slower rate than it is being drawn on to the block and accordingly, wire is being accumulated on the block, then the guide pulley 28 and bracket 28: will swing around the central axis of the block in the same direction as the direction of rotation of the block but at a slower speed.

I employ this characteristic motion of the guide over which the wire is withdrawn from the blocks to actuate'the automatic control mechanism for the speed of the motors driving the various blocks. That is, through a mechanism to be described in detail below, the rheostats 4i and 42, which control the motors 22 and 23 respectively, are automatically adjusted in response to movements of the pulleys 28 and 34, associated with the blocks l8 and I9 respectively, to control the speeds of the motors so that under ordinary operating conditions substantially the same number of turns of wire willremain on the blocks l8 and Is at all times, the motordriving either block being automatically adjusted with respect to the rate at which the wire is withdrawn to a succeeding block to insure that the wire is drawn on to and removed from the blocks at substantially the same speed.

In the embodiment shown 'in the drawings, the speed of the finishing block may be manually adjusted to a given value. Then the speed of the motor 23 will be automatically adjusted so that the block it will function to draw the wire through the die Elia at substantially the same speed that the wire is removed from the block IS to the die Mia and the finishing block 20. Similarly, the speed of motor 22 will be automatically adjusted so that the block ill will be driven at such a speed, depending upon the reduction eifected by the die 65a, that the wire will be drawn through the die Ma and on to the block it at substantially the same speed that it is removed from that block to supply wire to the die Elia as demanded by the operation of the block. l5.

A preferred form of automatic mechanism for so adjusting'the speeds of the motors and blocks is illustrated in the drawings. The mechanism associated with unit ill will be described, it being understood that the control mechanism is preferably identical for units ill and. it, or, in a machine embodying more than three blocks, for all blocks except the finishing block.

As shown in Fig. 3, the pulley 2% is supported by a bracket 29 which inturn is secured to an annular flange d5 extending from a hub 46. The hub is supported by suitable bearings 41 upon the upwardly extending shaft t8 which-is rigidlyniounted upon the block l8 and is coaxial therewith. Thus the bracket 29 and pulley 28 are free to swing around the shaft 48 and the pulley can properly guide the wire being withdrawn from the block regardless of any variation in rate of operation of the machine.

To tension properly the wire as it is being withdrawn from the block and to urge constantly the pulley into engagement with the wire, I preferably employ afriction drive which tends to rotate the hub and pulley in the direction of rotation of the block. This may comprise an annular plate 50 having an annular disk H of suitable friction material secured thereto, the friction material engaging the flat annular surface 52 formed on the upper part of the block II. The annular plate 50 has a threaded substantially cylindrical portion 53 extending upwardly down on the embodiment block 3 will be driven at the proper 7 2,272,187 therefrom, the internal threads on the cylindrical portion engaging external threads formed on the hub member 45, as indicated at 54. The driving engagement between the annular member 55 and the hub 45-is through the coil spring 55 which surrounds the cylindrical portion 53,

mounted on the annular flange 55 while the other end of the spring engages one of the series of pins 51, disposed in openings 58 in the upper flange 45. I I

By engaging the end 55 of the springwith different pins, the force exerted by the spring may be adjusted and correspondingly the frictional engagement between the friction material and the surface 52 may be varied by the adjustment of the spring. The arrangement is such that the clockwise direction.

one end of the spring engaging the screw 55 I flange rotates in a'clockwise direction and decreased when the flange rotates in a counter- Any suitable mechanism -may be employed for effecting this result, a preferred form of mechanismcomprising the motor driven rheostat 4| which controls the fied current of the motor 22 and which in turn i controlled by the switches 5| and 52. These switchas are operated by cams 55 and 54 engaging the switch levers 55 and 55, the cams being mounted upon a shaft 51 supported by asuitable bearing 55 preferably mounted on the upright plate 55 forming part of the frame of the unit. The shaft is rotated,either to leave both switches in the off position or to close one or the other, by means of action of the spring between the pin 51 and the screw 55 tends to rotate the threaded sleeve 55 with-respect to the threaded hub 45 in a direction to urge the friction material downwardly into engagement with the surface 52, that is, looking illustrated, if the pulley and flange are held stationary by the wire, the spring tends to rotate member 50 in a clockwise direction; however, this action is opposed by the counterclockwise rotation of the drum, which, a

through the friction material 5|, tends to rotate the member 55 in counter-clockwise direction and thus to reduce the pressure of.the friction material against the surface 55. Thus the friction drive is dependent on the adjustment of the spring and friction of the friction material against the sur- .face 52; with the result that the drive is automatically balanced in operation to maintain a tension in the wireproportional to the torque exerted by the spring between the members 50 and 45. By this means the force tending to rotate the upper flange 45 and thus .to swing the pulley about the axis of the block, and correspondinglythe tension onthe wire can be accurately controlled. In order to make for easy adjustment of the spring, the end engaging the pin 51 is pref-- erably extended outwardlybeyond the limits of the flange 45, to provide a convenient handle.

By this construction a simple and effective friction drive is provided, whereby the pulley is always urged to rotate in a direction of rotation of the blocker drum, l5, but whereby slippage can take place between the parts whenever the tension on the wire engaging the pulley exceeds a predetermined amount, which may be adis independent of the coeflicient of rection, for example, will result in closing the a lever 1| supported on pins 12 and 13 which are carried by the collar 14 keyed to the shaft 51. The leverextends downwardly and engages-the peripheral edge of a ring 15 mounted upon the flange 45 and rotatable therewith. Rotation of the flange 45 will thus result in therotation of the ring 15 which by frictional engagement will cause the lever- 1| to swing in one direction or the other depending upon the direction of rotation of v the flange and ring. The lever is urged into frictional engagement with the ring by the spring 15 acting between the upper end of the lever 1| and the washer 11 mounted on the upper pin 13. The

compression of the spring may be regulated by adjusting thepositior of the, washer on the pin. By this arrangement the lever 1| and the switches. 5| and 52 may be actuated immediately in response to movement of theflange 45 and ring 15, but continued rotation of the ring can have no damaging effect and willresult'in only slight wear, fortheconstruction is such that as the lever 1| is swung from its vertical position towards the extreme positions indicated in broken lines at H in Fig. 4, the pressure of the lever against the ring is gradually reduced'until in the extreme positions the pressure may be very slight.

The electrical connections are illustrated dia-' grammatically in Fig. 5'where it will beseen that swinging the lever 1| to the left in response to rotation ofthe ring I5 in counter-clockwise dicircuit through the switch'5 2. When this circult is closed, current will flow from the direct current supply main 15 through the conductor 5|, limit switch 52, switch'52, the fleld coil 55 of the rheostat motor. 55 and thence through the justed by the adjustment of the spring 55. The

tension on the wire is kept substantially constant for any given adjustment and any difference in the relative speeds at which the wire is beingdrawnon to and withdrawn from the block is promptly reflected and the swinging of the pulley 25 about the axis of the block. In the apparatus shown in the by rotation of the flange 45 the arm 55 of the rheostat 4| being swung in a drawings, the .pulley andflange will move in a 7 clockwise direction when the block is running too slowly, and move in a counter-clockwise direction when the block is running too fast (accumulating wire) with relation to the rate at which the wire is being withdrawn therefrom.

The rotation of the flange and pulley is utilized of the motor 22 so that the speed with respect to the speed of the succeeding block |5 so to control the speed that the accumulation of wire on the block' l5 will remain substantially constant. This is accomplished by connections between the flange and the controls for the motor 22 whereby the armature of the rheostat motor to the direct current supply line 55. This will result in the operation of the rheostat motor. 55 in a direction to decrease the speed of the main driving motor 22,

direction to'de'crease the resistance in the fleld circuit of the motor 22 and thus decrease its speed. Likewise if the lever 1| is swung to the right in response to clockwise rotation of ,the ring 15, the circuit will be completed through the switch 5| and limit switch55 (shown in open speed of the motor 22 is increased when the the rheostat comes to the end of its travel. This is accomplished by an extension on the rheostat arm 88 which engages the switches inthe extreme positions of the arm. In the; diagram shown the rheostat is at the position for the highest speed of operation of the motor 22, the circuit being from the D. C. supply line through the conductor 8| and all of the resistance of the rheostat to the rheostat arm 88 and from the arm through the-conductor 88 and the field 8| of the motor 22 back to the supply line 88. The arm 88 has opened switch 88 and stopped further operation of the rheostat motor in that direction, although the motor is ready for operation in response to closing of switch 82, to decrease the speed of motor 22. Thus no damage can take place to the'rheostat or the associated mechanism even though the friction ring II should continue to rotate in the same direction for a considerable length of time. This action may occur under various conditions of operation of the machine, particularly when the machine is being threaded and put into operation.

.As stated above, the automatic control mechanisms for units I8 and -II and their associated blocks I8 and I8 are substantially identical. Those skilled in the art will appreciate that an automatic control mechanism is not required for the finishing block 28, amanual control for the motor 24 driving this block preferably being provided. This control may comprise a rotatable control knob 82 secured to a shaft 83 extending to the rear of the unit where it is provided with a sprocket 84 connected by a chain 85 to a sprocket 96 mounted on the shaft of the hand.

operated rheostat 43. Thus the rheostat 43 and the speed of the motor 24 may be conveniently may be used to correlate the speed of that block with the speed of operation of the succeeding block I8.

The wire leaves theblock I8 over pulleys 34, 88 and 81 and is led through thefinishing, die IM to the finishing'block 28. As soon as willcient wire has been accumulated on the finishing block 28 to give suflicient frictional engagement between the block and the wire to permit the wire to be drawn through the finishing die, the tongs can be removed and the operation of the machine can be completely automatic. All of the motors are then put on their normal speed operation. The speed of the finishing block is manually adjusted ,to the desired rate by means of the control knob, and by means of the automatic mechanisms heretofore described, the

speeds of the blocks I8 and I8 are automatically correlated with the speed of the finishing block, the ultimate speeds of these blocks depending upon the relationship between the various diameters of the wire as it is drawn through the several dies.

Each of the units is provided with manual v means such as conventional push-button switches (not shown) for starting and stopping the respective motors and preferably the switches are arranged to operate the motors either at a slow speed for threading or at normal speed, in which latter case the speed of the motors is controlled by the respective rheostats associated therewith. These controls may be of any well-known type. In addition to the push-button control the units are preferably provided with bars I81, I82 and I83 respectively which are connected with switch mechanisms of any convenient type so that a push on any one of the bars will result in the stopping of the entire machine.

In operation the machine is threaded in the usual manner, that is, the wire or rod to be drawn, with a suitable point formed thereon, is first inserted through the die Ila, then by means of the usual tongs, is drawn around the drum I8 until the frictional engagement between the drum and the wire is suflicient to pull the wire through the die. The tongs are thenremoved and the desired number of turns are accumulated on the block l8. The wire is then led around the pulleys 28, 82 and 33, threaded through-the die lie and wound on the drum I8. The threading operations initially are carried out at slow speed of the motors, but if desired, the automatic control mechanism associated with the block I8 In'use, the automatic speed adjustment functions to bring the motors to proper speed a short time after the machine has been threaded and is operating normally. In long runs, the adjustments of the rheostats will automatically change in responseto changes in elongation occasioned by wear of the dies or changes in the characteristics of the material. However, these factors are all taken care of automatically as the need for adjustment arises. Accordingly, the machine may be operated for long periods of time so long as a continuous supply of wire is available to the first unit.

The automatic speed control of the machine increases the rate of production, and improves the efliciency of power utilization. The machine is also advantageous in that time is given between the successive drawing operations to permit the wire to cooland rest, which gives improved results, particularly with some types of alloys.

The foregoing description of a preferred form of my invention is given by way of example, it being evident that various changes and modifications in the preferred form described herein can be made by persons skilled in the art without departing from the spirit and teachings of my'invention. Therefore, it is to be understood that my patent is not limited to the preferred embodiment described herein or in any manner other than by the scope of the appended claims when given the range of equivalents to which my patentmay be entitled.

I claim:

1. In a continuous wire drawing machine comprising a plurality of dies, a plurality of blocks for drawing wire through said dies, said blocks being adapted to carry a reserve or accumulation of wire thereon, and means for withdrawing the wire from at least one of said blocks in an axial direction includinga guide for said wire rotatable about an axis substantially coaxial with said block, the combination of friction means tending to rotate said guide in the direction of rotation of said block, the tension of the wire against guidetending to rotate said guide in the opposite direction, and means controlled by the rotation of said guide for controlling the speed of said block to maintain the accumulation of wire thereon substantially constant;

in the rates atwhich wire is being drawn onto andwithdrawn from said block and means-controlled by the .rotationof said guide for controlling the speed of said block to maintain the accumulation of wire thereon substantially constant. I v

3. A continuouswire drawing machine comprising a plurality of dies, a plurality of blocks for drawing wire through said dies, said blocks being adapted to carry a reserve or accumulation of wire thereon, means for withdrawingthe wire from said blocks in, an axial direction including I a pulley for guiding said'wire, said pulley being swingable, about -an axissubstantially coaxial with said block, friction means tending to swing said pulley in the direction of rotation of said block, the tension of the wire against said pulley tending toswing said pulley in the opposite direction, andmeans controlled by the swinging'movement of said pulley for controlling the speed of said block to maintain the accumulation of wire thereon substantially constant.

4. In a continuous wire drawing machine of the type in which wire may be withdrawn from a block at a speed difierent from thatat which the wire is being drawn on to the block, a plurality of wire drawing blocks, at least one of said blocks having independently adjustable means for driving .said block and means automatically controlled by variations in the speed at which wire is withdrawn from said block as compared to the speed at which wire is being drawn on to said block for controlling the speed of said block so that the speed at which wire is withdrawn from said block will be substantially equal to the speed at which wire is being drawn on to said block and ,the accumulation of wire thereon will be [substantially constant.

5. A continuous wire drawing machine comprising a finishing block, a die associated therewith, means for driving said finishing block, manually operable means for adjusting the speed of said driving means, another block preceding said finishing block, a die associated therewith, said other block being arrangedto retain an accumulation or reserve of wire thereon, independently variable speed means for. driving said other said other block and controlled by variations in the speed at which wire is withdrawn therefrom as compared to the speed at which wire is drawn onto said-block for automatically adjust-' ing the speed thereof to maintain the accumulation or reserve of 'wire thereon substantially con- .stant in normal operation of the machine, re-

gardless of normal variations in the speed of said finishing block or normalchanges in the reduction eifected by the dies.

said block and coaxial therewithjfriction means tending to rotate said member with said block, a guide pulley for wire withdrawn from said block mounted on said member and -arranged so that engagement of the wire againstthe pulley tends to prevent rotation of said member andswitch means actuated by said flanged member whereby rotation of said member will result in operationof said motor driven rheostat and adjustmentof the speed of saiddriving motor.

'7. In axwire drawing machine, a block for drawing wire through a die, a driving motor for said block, an electrically operated rheostat for controlling the speed of said driving motor, a member mounted for rotation with respect to said rotate said member with said block, a guide for wire withdrawn from said block mounted on said member andarranged so that engagementof the wire with said guide controls the rotation of said member,; switch means actuated by said member, and electrical connections between said switch means andsaid rheostat whereby rotation of said member will result in operation of said rheostat and adjustment of the speed of said driving motor, and-a slip connection between said member and said switch means.

8. In a wire drawing machine having a frame structure, a block for drawing wire through a die, and a driving motor for said block, the combination of an electrically operated rheostat for controlling the speed of said driving motor, a

flanged member 'rotatably mounted upon whenwith said block, a guide pulley for wire withdrawnblock and coaxialtherewith, means tending to "ing carried by said block and coaxial therewith,

from said block mounted on said member and arranged so that engagement of the wireag'ainst the pulley tends to prevent rotation of said member, a ring rigidly mounted on and surrounding.

said flangedgmember and rotatable therewith, a

lever pivotallyemounted on said frame structure and frictionally engaging'said ring in a region spaced from said pivotal mounting whereby ro tation of said ring will result in a swinging movement of said lever-in one direction or the other,

depending on the direction of rotation of said ring, switch means actuated by said lever and electrical connections between said'switch means and said rheostat whereby rotation of said ring and flanged member will resultfin operation of said rheostat and in increasing or decreasing the speed of said driving motor, depending on the direction of rotation of said ring.

9. In a wire drawing machine having a frame structure, a blockfor drawing wire through a die, and a driving motor-for said block, the combination of an electrically operated rheostat for con trolling the speed of said driving motor, a guide for wire withdrawn from said block mounted for rotation about the axis of said block, the moveinent of said guide depending upon the relative rates at which wire is being drawn onto and withdrawn from said block, switch, means actuated by movement of said guide, there being a tween said switch means and said rheostat where- 6. Ina wire drawing machine, a block for drawing wire'througha die, a driving motorfor said block, a motor driven rheostat for controlling the speed of said driving motor, a flanged member rotatably mounted upon a bearing carried by by movement of said guide will result in operaguide.

' 10. In a wire drawing machine having a frame structure, a block for drawing wire through a die;

, friction connection between said switch means .and', said guide and electrical connections beand a driving motor for said block, the combination of an electrically operated rheostat for controlling the speed of said driving motor, a guide for wire withdrawn from-said block mounted for rotation about the axis of said block, the movement of said guide depending upon the relative' rates at which wire is being drawn onto and withdrawn from said block, a ring concentric" with said block and rotatable with said guide, a lever pivotally mounted on said frame structure and frictionally engaging said ring in a region spaced from said pivotal mounting whereby rotation of said ring will result in a swinging movement of said lever in one direction or the other, depending on the direction of rotation of said ring, switch means actuated by said lever and electrical connections between said switch means a and said rheostat whereby rotation of said ring and flanged member will result in operation of said rheostat and in increasing or decreasing the driving said member from said friction means and for urging said friction means into engagement with said block, and a guide pulley for wire withdrawn from said block mounted on said member and arranged so that engagement of the wire against the pulley tends to prevent rotation of said member and to oppose the action of the spring and thereby tends to reduce the pressure of said friction means against said block, whereby the tension of said wire may be controlled by adjusting said spring.

-12. In a wire drawing machine having a frame structure, a block for drawing wire through a die, and a driving motor for said block, the combination of a rheostat for controlling the speed of said driving motor, a guide for wire withdrawn from said block mounted for movement about the axis of said block, the movement'of said guide depending upon the relative rates at which wire is being drawn onto and withdrawn from said block, a ring concentric with said block and rotatable with said guide, means frictionally engaging said ring for controlling said rheostat whereby rotation of said ring will result in operation of said rheostat and in increasing or decreasing the speed of said driving motor, depending on the direction of rotation of said ring.

FRANK P. DAHIS'I'ROM.

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