US2581328A - Constant tension control - Google Patents

Description

2 SI-IEETS-SHEET 1 G. MALCOM CONSTANT TENSION CONTROL K M F 0 w A INVEN TOR.

GLEN M50031.

W M W Jan. 1, 1952 Filed July 1950 Patented Jan. 1, 1952 CONSTANT TENSION CONTROL Glen Malcom, Columbus, Ind., assignor to Reeves Pulley Company, Columbus, Ind., a corporation of Indiana Application July 7, 1950, Serial No. 172,504

The present invention-relates to a constant tension control, and more specifically to means for controlling the operation of a storage roll or the like, and a delivery roll associated therewith, in such a fashion that tension in the material passing between the storage roll and the delivery roll shall be maintained constant throughout the cycle of operation in spite of variations in the effective diameter of the storage roll during that cycle. A further object of the invention is to accomplish such tension maintenance by measuring the value and direction of any tendency toward variation in tension through the medium of a slipping drive connection having a constant slip ratio under given load conditions, such ratio being oppositely variable in response to load variations, and transmitting that measurement, through a pair of transmitter units of a selfsynchronous system, to a receiver unit of such system, and then causing that receiver unit to adjust a control element, in accordance with such measurement, to vary the angular velocity of the storage roll. 1 l

Further objects of the invention will appear as the description proceeds.

One embodiment of the present invention finds its primary utility in the control of a loom beam during the winding of strands thereon, and the invention has been shown, and will be described, in that environment.

To the accomplishment of the above and related objects. my invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific construction illustrated and described, so .long as the scope of the appended claims is not violated.

Fig. 1 is a plan view of an embodiment of my invention shown in association with a loom beam;

Fig. 2 is a fragmental transverse section taken substantially on the line 2, 2 of Fig. 1;

I Fig. 3 is a somewhat diagrammatic illustration of a variable speed transmission, the elements of the self-synchronous system associated therewith, and means for adjusting the parts of the transmission; and

Fig. 4 is a wiring diagram.

Referring more particularly to the drawings, it will be seen that I have shown a loom beam Io supported in suitable bearings, and a delivery roll II flanked by idlers I2 and I3, arranged upon axes parallel with the axis of the loom beam. A strand or strands of material I4 will be fed be-' tween the idler I2 and the delivery roll II,

8 Claims. (o1; zs -ss) partially around -the delivery roll, thence between the delivery roll and idler I3, and so to the beam I0 upon which it is to be wound.

A power source for the entire mechanism illustrated is indicated generally by the reference numeral I5, and, in the illustrated embodiment of the invention, comprises an electric motor I6 connected to drive through a speedvarying unit II. For the purposes of the present disclosure, it may be assumed that the unit I! will remain always in one setting.

A plurality of V-belts I 8 provide a driving connection from the unit I! to a pulley I9 fixed on a shaft '20 supported in suitable bearings upon an axis parallel to that of the beam' I0. Sprockets 2| on the shaft 20 are connected by chains 22 to drive sprockets 23 fixed on a parallel shaft 24; and sprockets 25 are connected through chains 26 to drive sprockets Z'I fixed on the roll Il. Thus, the roll II, in the illustrated embodiment of the invention, is positively driven at a velocity constantly proportional to the velocity Of the power source I5.

Sprockets 28 drivingly connected to the beam ID are driven, through chains 29, from sprockets 30 on the output shaft 3| of a gear unit 32 which, in turn, receives power from the output shaft 33 (Fig. 3) of a variable speed transmission indicated generally by the reference numeral 34. Sprockets 35 on the shaft 20 are connected by chains 36 to drive the input element 31 of a slipping clutch indicated generally by the reference numeral 38. This clutch will be of the type which provides a substantially fixed slip ratio between its input element and its output element during continuance of predetermined load conditions, but in which that slip ratio is variable oppositely in response to opposite variations of the load driven through the clutch. The output element 39 of the clutch 38 is operatively connected to the input shaft of the transmission 34, whereby the shaft 40 is driven through the slipping clutch 38.

In the illustrated embodiment of the invention,

I have shown a conventional Reeves variablespeed transmission in which a pair of allochiral cones 4|, mounted upon the shaft 40 for axial adjustment relative thereto, comprise a driving pulley, while a similar pair of cones 42 comprise a driven pulley, an edge active belt 43 providing a driving connection between said pulleys. A lever 44 is operatively associated, through thrust bearings, with one disc of each pair, while a lever 45 is similarly associated with the other disc of each painsaid levers being fulcrumed, intermediate their ends, as at 46 and 41. This arrangement is such that, when the projecting ends of the levers M and 45 are moved toward each other, the discs .H will be moved toward each other to increase the effective diameter of the pulley defined thereby, while the discs 42 will be correspondingly moved away from each other to decrease. the effective diameter of the pulley defined thereby, thereby increasing the velocity at which the pulley 52 and the shaft 33 will be driven in response to constant speed rotation of the shaft 40. Obviously, separation of the projecting ends of the levers 54 and 15 will modify the speed ratio between the shafts 40' and 33, in the opposite direction.

Mechanical means, indicated generally by the reference numeral 48, is provided for controlling the positions of the levers 44 and 45. Such means may advantageously take the form of the control device illustrated and described in the patent to Harry Clay 2,306,541 issued December 29, 194.2. Thus,v the. mechanism is; may comprise, a fluid motor including a cyT- ihdler 5.9.. connected to. move with the lever 45 and a piston 50; reciprocably mounted inv the cylinder wand operatively connected to the lever 45, together with the valving means 51 for controlling relative movement of the cylinder 4-9 and piston 50.. The. valving means includes a control lever 52. in the illustrated embodiment of the invention, a bell crank lever 53 has one-arm 55connected by a link 54 to the lever 52 so that movement of its other arm 56 in opposite directions will result in opposite: movementsv of they lever 52.

A sprocket 51. carried on an extension of. the shaft 20,, is connected by a' chain. 58 todrive a sprocket 59 carried on the rotor or armature 65 of a, transmitterunit (ii of a self-synchronous system, A. sprocket 62 on the; shaft, 40, is connected by a chain: 53, to drive a sprocket 6.4 on the armature 55 of. a second transmitter unit 66. Electrical connections are, established be,- tween the units SI. and 6,6 and a. receiver unit 61, whereby the output: voltages of, the transmitter units are oppositely impressed upon the receiver unit. Thus, so long as the output voltages-of. the units ti and 66 are equal, the armature 68 of the receiver unit. 6-! willbe; locked against rotation; but when a difference exists between the output. voltages. of the two transmitter units, the, armature 58 or the receiver unit-will be rotated in adirection, and. ate rate, determined, by the direction and;.magnitude of that difference.

It: willv be noted that the shaft 20-. will rotate always at, a constant speed, while the speed of the shaft 40. will always be somewhat lower, since it, is drivenv through the, slipping clutch 3 8, and will vary somewhat in. response to variations in the slip ratio, oi the clutch 35. In order that the output voltage of the unit. 66 may equal that of the unit 6| during continue ance of normal slip-ratio: within the.- clutch 38, the two units :1: and 65 may-be difierently wound tocompensate for the difference in speed, or the ratio in the drive trainbetweenthe shaft 40 and the armature 55; may differ from that'in the drive train between the shaft 20 and the armature 6,0. l he armature: B8 of the receiver unit 61. carries a, drum 69' upon. which is wound acable 15: connected to the; arm 56' of the bell crank lever: 53; Obviously, as. the, armature 68; rotates" in" one direction, the. cable 70 will. be: wound to; swing the lever 53% in acounter-- clockwise direction. In order that the assembly may be responsive to shift the lever 52 in either direction, means is provided for resiliently opposing such movement of the lever 53. In the illustrated embodiment of the invention, a second cable F2, likewise connected to the lever arm 55, passes over a guide pulley i3 and supports a counterweight I! of such value as to be capable of shifting the lever 53 in a clockwise direction upon opposite rotation of the armature 68 to pay out the cable Ill.

In operation, the delivery roll II will be rotated to feed the strand I4 toward the beam it at a constant lineal velocity. While I have illustrated an embodiment of my invention in which the delivery roll II is driven from the power source i5, it will be clear that its rotation might be otherwise controlled.

As shown, and assuming that the transmission 34 is initially set to cause rotation of the beam i6 at the velocity of'the roll 5 I, it will be obvious that, as material begins to build up on the beam ill, the effective diameter of the beam is thereby increased,, whereby tension in that reach of. the strand. extending between the beam and the idler 13 will build up. When that tension for which the mechanism ispreliminarily set is attained, the clip in the clutch 3.8 will be such as to lock the armature $8 of the receiver unit 61. As the system continues to operate, there will be a tendency for the tension in thecritical reach of the strand Hi to increase further. which will cause excessive slip in the clutch 38, whereby the shaft 40 and its transmitter unit 66 will. lag behind the shaft 2 6 and its transmitter unit-6|. Thereby, the armature 58 will be. rotated toswing. the lever. 53 in. a counter-clockwise direction to shift the lever 53: to actuate the motor. 43' to separate the levers 44 and 45; thereby reducing the rotational speed of the-shaft 33. Thus, the tension in the critical reach: oi. the strand: will be reduced: andthe optimum slip ratio will be reestablished irr. thev clutch 39; to. reestablish equilibrium between the two voltages impressed orrthe. unitififi. Actually, of course, in practice, the clutch 35-" will continuously slip by: an amount slightly in. excess of its optimum slip' ratio, whereby the arma-- ture 68 will becontinuously rotated to maintain, at all times, the predetermined tension value in the critical reach of the strand.

In Fig. 4, I have diagrammatically illustrated the two transmitter units 6| and 66' and the receiver unit 6?, together with the locking connections therefor, supplied from a line through a main switch 82. Line wire 83 leads from one side of the switch 82 to one switch arm 85 of a switch assembly 86, said arm normally being in contact with. a terminal 86. on one side of the. locking connections. A terminal 88 at" the other side of. the locking comiections is normally contacted by a switch arm 8'! which. is connected, by wires 89, 8d and. 5!, with. a. line wirev 8 5 at the opposite side of the switch 82". During the cycle of operation above described, the switch arms 85 and 8? are intheir illustrated positions, and the self-synchronous system is-in operative condition.

When albeam has been filled, it must be doiied, and the system should be readily returned, quickly and, easily, to. a starting speed ratioduring the short period. requiredto replace-the filled beam with anew beam to be filled. Such return of the: system is simplified, inthe emf-- '5 'bodiment of my invention illustrated, by the means now to be described.

The switch arms 85 and 81 are located within the actuating influence of a relay including a 'coil 92, one end of which is connected by a wire 93 with the wire 99, and the other end of which is connected by a wire 94 to a terminal 95 of a normally open switch including a bridge piece 96 movable to a position bridging terminals 95 and 91. 'A wire 98 leads from the terminal 91 to line wire 83. When the beam has been filled and is to be doifed, the bridge piece 96 is manually moved into engagement with terminals 95 and 91, thereby establishing an energizing circuit for the coil 92 leadin from wire 83 through wire 98, terminal 91, bridge piece 96, terminal 95, wire 94, coil 92, wire 93, wire 99, and wire 9| to line wire 84. Energization of the coil 92 immediately shifts the switch arms 85 and 81 out of engagement with their respective contacts 86' and 88, thereby breaking the connections of the self-synchronous system and freeing the unit 61 from domination by the units 6| and 66. The counterweight II will now swing the bell crank lever 53 in a clockwise direction, unwinding the cable I9 from the drum 69 which, with the armature 68, will rotate freely after the connections of the self-synchronous system have been broken.

The above-mentioned movement of the bridge piece 96 closes, also, an energizing circuit for a relay in a second switch assembly 8|, including a coil I99, one side of which is connected by wire 99 to the wire 94, and the other side of which is connected by wire I9I with the wire 9|. This circuit may be traced from wire 83 through wire 98, terminal 91, bridge piece 99, terminal 95, wire 94, wire 99, coil I99, wire I9I, and wire 9| to wire 84.

Energization of the coil I99 shifts switch arm I92 into contact with a terminal I93, said terminal being connected by wire I94 with wire 83. The switch arm is connected by wire I95 to a terminal I95 of a normally closed switch including a bridge piece I91 which engages also a terminal I98 connected, by wire I99, with wire 94. Closure of the switch arm I92 upon the terminal I93 establishes a holdin circuit for the coil 92 leading from wire 83 through wire I94, terminal I93, switch arm I92, wire I95, terminal I96, bridge piece I91, terminal I98, wire I99, wire 94, coil 92, wire 93, wire 99 and wire 9| to wire 84; and a holding circuit for the coil I99 following, as traced above, to wire 94 and thence through wire 99, coil I99, wire I9I and wire 9| to wire 84. The locking connections of the selfsynchronous system, thus, will remain broken, once the button carrying the bridge piece 99 has been pressed, until the button carrying the bridge piece I9! is subsequently pressed to break the holding circuits Preferably, I will provide a light signal system for indicating the current conditions of the parts of the system. Thus, a wire II9 leads from the wire 83 to one side of a light bulb III, the other side of which is connected by wire II2 with line wire 84. So long as the switch 82 is closed, the light III will be energized. The switch mechanism 8| includes a second switch arm II3 which, upon energization of the coil I99, will be moved into contact with terminal H4. The terminal I I4 is connected by wire I94 with line wire 83, and the switch arm H3 is connected by wire II5 with one side of a light bulb H6. The other side of said light bulb is connected, by wire 1,

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through normally closed switch I I9, to wire I23 and so to line wire 84. Thus, when the coil I99 is energized, the bulb III; will be lighted; and it will stay lighted, to show that the system is in the course of returning to starting position, until the lever 44 strikes and moves the plunger I22 on which is carried bridge piece I29 normally bridging the terminals H8 and I2I of the switch II9.

When the operator sees that the light IIE has been extinguished, he knows that the system is in condition to be restarted by depression of the reset button carrying the bridge piece I91. When that button is depressed, the holding circuits for the relays 92 and I99 will be broken, and the switch arms 85, 81, I92 and II3will return to their illustrated positions, whereafter the cycle above described will be restarted.

Clutches of the character indicated at 38 are well known in the art and, since the details of clutch structure form no part of the present invention, the clutch has been illustrated diagrammatically. One such clutch currently available on the market is identified as a Hilliard adjustable-while-running slip clutch. The hand wheel I24 is operable to vary the torque transmission capacity of the clutch 39, thereby varying the value of the gross tension maintained in the stretch of material between the idler I3 and the beam I9.

It will be clear that the illustrated mechanism will be effective to control tension in the same way, if the roll I9 isoperating as an unwinding roll, by driving the rotor 68 in the opposite direction as the eifective diameter of the roll I9 decreases during unwinding.

I claim as my invention:

1. In a device of the class described, a delivery roll and a storage roll, said delivery roll being driven at a velocity constantly proportional to the lineal velocity of a strand running between said rolls, and means for controlling tension in that reach of such strand extending between said rolls, comprising speed-varying means for driving said storage roll including an element shiftable oppositely to vary oppositely the speed at which said storage roll is driven, and including a slipping drive connection having a substantially fixed slip ratio under predetermined load conditions, such ratio being oppositely variable in response to opposite load variations, a transmitter unit of a self-synchronous system having an armature operatively connected to rotate at a velocity constantly proportional to the velocity of said delivery roll, a second transmitter unit having an armature driven through said slipping drive connection, the effective voltage deliveries of said transmitter units being equal during continuance of such fixed slip ratio, a receiver unit having an armature, electric connections between said transmitter units and said receiver unit impressing the outputs of said respective transmitter units oppositely on said receiver unit armature, and means operatively connecting said receiver unit armature to shift said element.

aces-p28 siliently resisting movement of said valve means inv response to winding-in rotation of saidreceiver unit armature.

6,, The device of claim in which said means resisting movement of said valve means is a counterweight.

7. The device of claim 1 including switch means in said; electric connections operable at will to break said, connections thereby freeing said receiver unit armature from the domination of. said transmitter units.

8'. In a device of the class described, a storage roll, a delivery roll, a power source, means connecting said power source to drive said delivery roll at a velocity constantly proportional to that of said power source, a transmitter unit of a self-synchronous-system, having a rotor, means connecting said rotor to rotate at a velocity con stantly proportional tothat of said delivery roll; a speed-varying transmission comprising an input shaft, an output shaft, means for transmitting power between said shafts and an element shiftable oppositely to vary oppositely the speed ratio between said shafts, means connecting said power source to drive said input shaft including a slipping drive connection having a substantially fixed slip ratio under predetermined load conditions, such ratio being oppositely variable in response to opposite load variations, a second transmitter unithaving a rotor, means connect.- ing said input shaft to drive said second transmitter unit rotor at a velocity constantly proportional to that of said input shaft, a receiver unit having a rotor, electric connections between: said transmitter units and said receiver unit operative to lock said receiver unit rotor against tation during continuance of such fixed slip ratio and to enforce rotation of said receiver rotor in one direction upon increase in such ratio and rotation of said receiver rotor in the opposite direction upon decrease in such ratio, and means operatively connecting said receiver unit rotor to shift said element.

GLEN MALCOM.

No references cited.

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