US2205213A

US2205213A - Tension device for wire drawing benches

Info

Publication number: US2205213A
Application number: US147307A
Authority: US
Inventors: Gerhard P Lessmann
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1937-06-09
Filing date: 1937-06-09
Publication date: 1940-06-18
Anticipated expiration: 1957-06-18

Description

June 18; 1940. R MANN 2,205,213

TENSION DEVICE FOR WIRE DRAWING BENCHES Filed June 9, 1957 l N V E N TO R @nam PAwmwm.

.ATTOIRNEY '15 tension upon the wire between each drum and A further object of my invention is to provide 15 85 cross section area, as would increase the drawing Another Object of my invention is o p v de 35 Patented June 18, 1946 r fiTA'FES PATENT OFFKIE TENSIQN DEVICE FOR WIRE DRAWING BENCHES Gerhard Lessmann, Forest Hills, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application June a, 1937, Serial No. 147,307 s Claims. (01. 205-14 My invention relates, generally, to wire drawa die in response to variations of the physical mg machinery and, more particularly, to a syscharacteristics of the wire.-

tem for maintaining the proper back tension A further object of the invention is to proupon a wire as it is being drawn through a die. vide a device which shall function to increase I In the manufacture of wire, it is common practhe back tension on a wire which is being drawn tice to pull the wire stock through a die to rethrough a die in response to an increase in duce its section by rotating a drum upon which resistance-to-drawing as the wire passes through the wire is mound, then unwinding the wire from the die.

the drum and drawing it through a succeeding Another object of the invention'is to provide die to further reduce its section by winding it a control system which shall function to increase upon another drum and thus continuing through the back tension on a wire as it is being drawn successive dies until the desired reduction has through a die in response to an increase in been obtained. load on the motor that is drawing the wire It has been found desirable to maintain a back through the die.

the next succeeding die. This back tension a device which shall function to maintain a submakes it possible to pass larger stock through stantially constant back tension on a wire as a given die than could be passed without back it is being drawn through a die. tension and thus reduces the number of dies re- Another object of my invention is to provide quired for a given reduction. This back tension a device for maintaining a substantially constant 20 also reduces the work required to be done in back tension on a wire as it is being drawn each die for a given reduction of wire section through a die so long as the front tension on the and thus decreases the heating of the wire caused wire remains substantially Constantby drawing it through the die. For this reason, A further object of my invention is to provide. the wire may be drawn through the die at a a system for so controlling the relative speed greater speed than when back tension is not of two successive wire block motors as to mainemployed, with the same amount of heating. tain a substantially constant back tension on a For a given material, a given forward pull, a wire as it is drawn through a die. given desired reduction and a given speed of A further object of my invention is to provide material feed, a definite ratio exists between a system-for drawing wire which shall function 30 the forward pull on the wire and the back teno p d a given reduction of the Wire W t sion which will give the best results. It follows a minimum of apparatus, a minimum number that such changes in the physical characteristics of steps in the drawing process and at a maxiof the material, such as ductility, hardness and .mum speed.

a system for drawing wire which shall function to prevent breaking of the wire during the draw ing process by automatically limiting the stress on the die block during the drawing operation. These and other objects and advantages of my I This ratio varies with different forward invention may be readily understood by reference 40 to the following detailed description taken in sions and is alwa such that an increase in forward tension r zuires that there be an inqi fi with the accompanymg drawing m resistances in the die wouldincrease. the forward pull on the wireind would'not provide the proper ratio between the forward pull on the wire and the back tension if the back tension were a fixed amount.

crease in back tension to secure the best draw- Figure 1 is a diagrammatic illustration of the 8 lesllltselements of structure of the preferred embodin the mrward Pull and die reslstance are ment of my invention and their cooperative reallowed to become great enough, there is danger lationships; and of the wire being pu a Y Pmviding the Fig. 2 is a diagrammatic illustration of a modi- 9 increase in back tension with increase flcation of the structure illustrated in Fig. 1. 5 of die resistance and f on p h s dan er is In carrying out the preferred embodiment of eliminated. my invention, I provide a floating sheave over The object of y invention is to Provide 8 which the wire passes in travelling from a wire device which shall function to vary the back block to the succeeding die block. The sheave 3.; tension on a wire which is being drawn through is carried by'a piston which is movable in a cylinder by fluid pressure which is applied to the cylinder. The sheave and piston are so mounted as to increase the back tension of the wire when fluid pressure in the cylinder is increased. The die block is so mounted as to be deflected by the front tension on the wire, 'or the frictional resistance of the wire in the die block, the degree of deflection being proportional to the front tension or frictional resistance. The deflection of the die block is made to control a regulator which, in turn, causes increase of the fluid pressure in the cylinder to increase the back tension on the wire.

A regulator is controlled by the positioning of the back tensioning sheave to vary the speed of the preceding wire block motor to air in maintaining increased back tension without the necessity of continuous movement of the sheave supporting piston.

A modification of this system operates to regulate the fluid pressure in the cylinder in response to changes in the loading of the wire block motor which is drawing the wire through the die.

Referring to Fig. 1 of the drawing, wire 3 is wrapped around motor-driven drum 4, and is drawn through die 5 to reduce it in section. Wire 3 is fed to the die 5 over guide sheave 6, after being unfound from motor-driven drum 7 and passing over tensioning sheave 8. Drums 4 and 1 are driven by motors 9 and I0, respectively.

The die 5 is mounted on a pivoted arm II, which is biased by spring |2 to move in a direction opposite to that in which the wire is moving. A contact element |3,is mounted on arm H, and is disposed to close a set of contacts M in the event that the pull of the wire on the die exceeds a predetermined amount, and to close contacts |5 in the event that the pull on the die is less than a predetermined amount.

The tension on the wire 3 as it passes between the drums 4 and 1 is regulated by fluid pressure operated piston l6, which moves in the pivotally mounted cylinder I! under force of fluid pressure supplied by regulating valve l8, which regulates the fluid pressure supplied from the pressure reservoir to the cylinder l1.

The pressure regulating valve |8 comprises a chamber l9, valve and chamber 2|, which is connected to cylinder IT. The flexible diaphragm 22 forms one wall of chamber 2|, and is connected by rod 23 to the valve 20. Spring 24 acts on the underside of the diaphragm 22 to hold the valve 20 in such a position as will supply a predetermined pressure to cylinder l1;

Variation of the pressure in cylinder I1 is brought about by a variation in the pressure on the lower side of diaphragm 22 which is efiected by varying current flowing in a solenoid coil 25, which acts upon a solenoid core 26 to exert a force on the diaphragm 22 opposite to the force of spring 24.

A regulator 21 so governs the current in solenoid coil as to supply a pressure incylinder H, which varies with the displacement of the die block 5. This regulator comprises a relay 28, which is connected across the supply lines XY, in series with a resistance 29, which is normally shorted by the contact element of relay 3|. The circuit for relay 28 extends from the supply conductor X through conductor 32, resistance 29, which is shorted by contact element 30 through

conductors

33 and 34, conductor 35, the coil of relay 28, and conductor 39 to the other side of the source of supply Y. When relay 28 is energized, its contact element 29a closes acircult through the coil of relay 3| which extends from the supply conductor K, through conductor 36, contact element 28a, conductor 31, the coil of relay 3| and conductor 38 to the other side of the source of supply Y.

With relays 3| and 28 connected as described.

-it will be seen that relay 28 is being intermittently energized and deenergized by the shorting of resistance 29 by the contact element 30 or the relay 3| and the removal of the short from the resistance 29 by a contact element 30 of relay 3| when relay 3| is energized through the closure of contact element 28:: of relay 28. This produces a vibration of arm 40, which is operated by relay 28, and produces a movement of movable contact element 4| between stationary contacts 42 and 43.

It will be seen that one of the contact elements I 5, associated with the die 5, is connected by conductor 44 with the lower stationary contact 43 and that the other contact element |5 is connected to the coil of relay 45 through conductor 46. It will also be seen that stationary contact 42 of the regulator is connected through conductor 41 to one of the contact elements I4, and that the other contact element I4 is connected through conductor 48 to the coil of relay 49.

Thus it will be seen that, as contact element 4| of the regulator alternately engages its associated contact elements 42 and 43, relay 45 will be energized in the event that movable contact element I3, actuated by the movement of the die, is in enagagement with contact elements l5, and that relay 49 will be energized in the event that movable contact element I3 is in engagement with contact elements l4.

The operating circuit for relay 45 extends from supply conductor X, through conductor 36, coil of relay 45, conductor 46, contact elements I5, contact element l3, conductor 44, contact elements 43 and 4|, arm 40, conductor 50 and conductor 39 to the other side 01' the source of supply Y, The circuit for relay 49 extends from supply conductor X, through conductor 36, coil of relay 49, conductor 48, contact elements |4, movable contact element l3, conductor 41, contacts 42 and 4|, arm 40, conductor 50 and conductor 35 to the other side of the source of supply Y.

The circuit for solenoid 25 extends from supply conductor X, through conductor 35, resistance 5| which may be shorted by the contact element 52 of relay 45 when the relay is energized, resistance 53, which is normally shorted by contact element 54 of relay 49 when relay 43 is deenergized, conductor 55, solenoid coil 25, resistanc 56, and conductor 51 to the other side of the source of supply Y.

It will be seen that energization of relay 45 will raise contact element 52 to short circuit resistance 5|, thus decreasing the resistance in series with solenoid 25. This decrease in resistance in the circuit of coil 25 will cause increased current flow in the coil and will cause a decrease in the pressure supplied to cylinder H, The energization of relay 49 will cause its movable contact element 54 to remove the short from resistance 53, thus increasing the resistance in the circuit of solenoid 25 and causing decreased current flow in the solenoid. This will result in causing valve 20 to increase the pressure in cylinder l1 and to thus cause upward movement of sheave 8.

In order that the travel of the piston I may of motor it to thus govern the rate of feed of wire 3 to the die 5. The regulator 58 controls the current flow in the field coil 59 of motor In in response to predetermined movements of the sheave 8. The regulator comprises relays 60 and El, which function very much the same as relays 3| and 28, respectively, in regulator 21, hereinbefore described, and produce a vibration of arm 62 to move contact element 63 alternately into engagement with contact elements 64 and 65. Contact elements 64 and 65 are connected to relays 66 and 61, which function in the manner described hereinbefore in connection with relays 55 and 49, respectively, to vary the current in field coil 59 by including resistance 68 in, or removing resistance til'from, the field winding 59 of the motor I0.

In the operation of the device, in the event that for some reason, such as achange in the hardness of the material of the wire, too great a pull is placed upon wire 3 in passing through die 5, the die will move against the tension of spring 12 to cause movable contacts element 43 to bridge contact elements it and close the circuit to relay 39, which circuit will be intermittently completed through contact elements 4| and 42 of the regulator. This intermittent energization of relay 49 will cause its contact element 54 to intermittently remove the short circuit from resistance 53 and thereby decrease the current in solenoid 25. The decrease in current in solenoid 25 will cause valve 20 to increase the pressure in cylinder II which will tend to cause an upward movement of piston l6 and sheave 8 to increase the back tension on the wire.

The increase in the back tension on the wire 3, by upward movement of sheave 8, will permit the wire to be drawn through the die 5 without increasing the tension on the wire as it is pulled by drum 4 to such an extent as would be likely to break the wire at the die. In other words the increase in back tension reduces'the resistance to drawing and prevents the drawing tension from becoming excessive.

In the event of such a change in the character of the wire as would cause decreased resistanceto-drawing and would allow spring l2 to move die block 5 to the left, decreased tension on the wire would be brought about by closure of contact element l3 to decrease the pressure in cylinder ll through increase in current in solenoid 25 by energization of relay B5 to short circuit resistance 5|.

In the event that continued increases of tension in the wire are required to maintain the proper balance on the two sides of the die 5, regulator 58 responds to the displacement of contact element 65 which moves with the sheave it to increase the current in field 59 of motor W to thus tend to decrease the speed of motor in and thus increase the back tension on wire 3. This regulation of the field current of motor it) perproper tensioning of the wire with a limited displacement of the piston 96 and sheave 8.

In the modification of Fig. 2, I have shown a means for controlling the operation of the regulator in response to variations of the load on motor 9 which are caused by variations in the resistance-to-drawing of the wire in the block 5. In this modification, a resistance 10 is connected in series with the motor 9, and a relay ii is connected across this resistance so as to be responsive to the voltage drop in the resistance. Like reference characters indicate the same or equivalent elements in the two figures.

In the operation of the modification of Fig. 2, in the event that the resistance-to-drawing in the die 5 increases, the increased load on the motor 9 will cause increased drop in resistance It), thus causing relay H to move contact element l3 against the tension of spring, i2 to bridge contact elements M. This will close an energizing circuit for the relay 49, as hereinbefore described in connection with the operation of the apparatus shown in Fig. 1, to tend to cause an upward movement of sheave 8 to increase the backward tension on the wire 3.

In a like manner, decrease in resistance-todrawing in die block 5 will cause a decrease in the current drawn by motor 9 and will permit spring l2 to move contact element 83 to bridge contact elements is, which will energize the relay 45 to cause the regulator Hi to reduce the pressure in the cylinder i1 and thus decrease the back tension on the wires.

In compliance with the requirements of the patent statutes, I have shown and described herein described, but is capable of modification by one skilled in the art, the embodiments herein shown being merely illustrative of the principles of my invention.

I claim as my invention:

1. In a system fordrawing wire, means for drawing a wire through a die, means mounting the die for movement in accordance with the drawing force exerted on the die, means for maintaining a back tension on the wire as it is drawn through the die, and means for automatically varying the back tension in response to movement of the'die.

2. In a system for reducing the cross-sectional area of a length of material, means for passing the material through a device which will cause reduction in the cross-sectional area of the material including means for exerting a forward tension on the material, means for maintaining a back tension on the material, and pressure fluidoperated means acting on the material responsive to variations in the forward tension for varying the back tension on the material.

3. In a wire drawing system, means for drawing a wire through a die to reduce the cross-sectional area of the wire, means for maintaining a back tension on the wire, means including a fluid pressure operated device acting on the wire ior automatically varying the back tension on the wire in response to .variationsin physical characteristics of the wire.

4. In a wire drawing device, a die, means for pulling the wire through the die, means for maintain a back tension on the wire, means including a fluid pressure operated device acting on the wire for automatically varying the back tension on the wire in response to variations in the resistanceeto-drawing of the wire.

5. In a system for drawing wire, means for drawing a wire through a die, means for maintaining aback tension on the wire, means including a fluid pressure operated device acting on the wire for automatically varying the back tension on the wire in response to variations in the loading of the means for drawing the wire through the die. I

6. In a system for drawing wire, a die,

i'or drawing a wire through the die, means for maintaining a back tension on the wire, means including a fluid pressure operated device acting on the wire for automatically varying the back tension on the wire in response to the variations in the force exerted on the die in drawing the wire through the die.

7. In a system for drawing wire, a die, means for drawing a wire through the die, means for maintaining a back tension on the wire, means including a fluid pressure operated device acting on the wire for controlling the back tension on the wire, and means responsive to the variations in the force exerted on the die in drawing the wire through the die for varying the fluid pressure acting on the fluid pressure operated device to thus vary the back tension on the wire.

8. In a wire drawing device, means for pulling a wire through a die, means for maintaining a back tension on the wire, means including a fluid pressure operated device acting on the wire for controlling the back tension on the wire, and means responsive to the variations in physical characteristics of the wire for varying the fluid pressure acting on the fluid pressure operated device to thus vary the back tension in accordance with variations in the physical characteristics of the wire.

9. In a wire drawing system, a die, means for pulling the wire through the die, means for maintaining a back tension on the wire, means including a fluid pressure operated device acting on the wire for controlling the back tension on the wire, and means responsive to the loading of the pulling means for varying the fluid pressure acting on the fluid pressure operated device to thus vary the back tension in accordance with variations in the loading of the pulling means.

10. In a wire drawing device, in combination, a die, means for pulling a wire through the die to reduce its cross-sectional area, means for so mounting the die as to permit a displacement of the die an amount which is proportional to the. force exerted on the die by the wire as it is pulled through the die, means for maintaining a back tension on the wire, means for adjusting the back tension on the wire, and means whereby the back tension adjusting means is actuated in accordance with the degree of displacement of said die.

11. In a wire drawing device, a die, means for pulling a wire through the die comprising a motor, means for maintaining a back tension on the wire, pressure-fluid actuated means acting on the wire for adjusting the back tension on the wire, and means whereby the back tension adjusting means is actuated in accordance with'the loading of the motor.

12. In a wire drawing device, a die, means for pulling a wire through the die, means for maintaining a back tension on the wire comprising a member over which the wire travels before entering the die, said member being so disposed as to cause variation of the back tension on the wire when the member is moved, means governing the movement of the member comprising a fluid actuated piston, and means responsive to the force exerted on said die in pulling the wire through the die for controlling the fluid flow to said piston to thereby vary the back tension on said wire in accordance with the force exerted on said die by said pulling means.

13. In a wire drawing device, a die, means for pulling a wire through the die comprising a motor, means for maintaining a back tension on the wire comprising a member over which the wire travels before entering the die, said member being so disposed as to cause variation of the back tension on the wire when the member is moved, means governing the movement of the member comprising a pressure fluid actuated piston, and means responsive to the loading of said motor for controlling the fluid flow to said, piston to thereby vary the back tension on said, wire in accordance with the loading of said pulling motor.

14. In a wire drawing device, a die, means for pulling a wire through the die comprising an electric motor, means for maintaining a back tension on the wire comprising a member over which the wire travels before entering the die, said member being so disposed as to cause variation of the back tension on the wire when the member is moved, means governing the movement of said member comprising a fluid actuated piston and an electrically controlled valve device for governing the fluid flow to said piston, a current responsive device responsive to the load current to said electric motor, means whereby said current responsive device controls the operation of said electrically controlled valve device to thereby vary the back tension on the wire in accordance with the loading of said electric motor.

15. In a wire drawing device, a die, means for pulling a wire through the die, means for maintaining a back tension on the wire comprising a member over which the wire travels before entering the die, said member being so disposed as to cause variation of the back tension on said wire when the member is moved, means governing the movement of the member comprising an electrically controlled fluid actuated piston, means for so mounting the die as to cause displacement of the die in the direction of travel of the wire in accordance with the force exerted upon the die by the wire as it is drawn through the die, means whereby the displacement of said die controls the operation of said electrically controlled fluid actuated piston to thereby vary the back tension on the wire in accordance with the force exerted upon the die by the wire as it is drawn through the die.

16. In a wire drawing system having a series of motor-driven wire blocks each of which draws a wire through a die and from each of which the wire is fed to the next succeeding die, a die, a member over which a wire which is being drawn travels in passing from a feeding wire block to the die, said member being so disposed as to vary the tenson in the wire between the die and the feeding wire block upon movement of the member, means responsive to the resistanceto-drawing of the wire for moving said member, and means responsive to predetermined movement of said member for varying the speed of the feeding wire block motor.

GERHARD P. LESSMANN.