US2316508A - Strand handling apparatus - Google Patents

Description

April 13, 1943. w. C EWALDSON 1 5 STRAND HANDLING APPARATUS Filed Aug. 14, 1941 '3 Sheets-Sheet l W. .6. EWA LDSON BY I emw M ATTORNEY April 13, 1943. w. c. EWALDSON STRAND HANDLING APPARATUS V 3 Sheets-Sheet 2 Filed Aug. 14, 1.941

"aamwiw ATTORNEY p 3,1943. w. c. EWALDSON v 2,316,508

' STRAND HANDLING APPARATUS Filed Aug. 14, 1941 3 Sheets-Sheet 3 I I a \r s: 4

I I D o A m 2 =9 2 L a x INVEN TOR W.G. EWALDSO/V 8) ,4 r m NEY Patented Apr. 13, 1943 UNITED STATES PATENT OFFICE 2,316,508 I STRAND HANDLING APPARATUS Waldemar C. Ewaldson, Millington, N. J'., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application August 14, 19511, Serial No. 406,855

8 Claims.

This invention relates to strand handling apparatus, and more particularly to apparatus for controlling the longitudinal speed of electrical cable while in process of manufacture.

In the manufacture of cable, especially of the somewhat complexly organized multi-conductor cables employed in telephony, a plurality of constituent strands may be rotated to intertwist the strands while the intertwisted strands are propelled longitudinally. The pitch, or degree of twist, of the cable thus produced depends upon the ratio between the rotary speed of twisting and the linear speed of advance of the cable. The cable is usually advanced by being wound up on a take-up reel or drum, with or without the aid of some form of capstan; or, if the cable is to undergo further treatment, may be advanced by a capstan. Being thus pulled along against resistance offered by the twisting means and by tensioning devices applied to the supply reels or to the strands being supplied, tension is maintained in the cable by the advancing or pulling means. If the resistance rises or drops for any reason, the tension will rise or drop, and the pulling means will pull the cable along too slowly or too rapidly. Hence the speed of advance of the cable tends to vary more or less inversely as the tension; and uniformity of pitch of the cable depends upon uniformity of tension.

An object of the present invention is to provide an improved. apparatus actuable by and in response to a change in tension in an advancing cable or other strand to correspondingly alter the speed of advance, which apparatus shall be sensitive and quick to respond, shall be efiective in proportion to the magnitude and .swiftness of the change in tension, and shall operate to control over compensation and consequent hunting.

With the above and other objects in view, the invention may be embodied in .a strand handling apparatus having means to advance a strand longitudinally and means adjustable to. control the speed of advance of the strand ,-means responsive to variations of tension in the strand to adjust the speed control means, and means to cause "the responsive means to actuate the speed control means intermittently.

Other objects and features of the invention will appear from the following detailed description of one embodiment thereof taken'in connection with the accompanying drawings in which the same reference numerals areapplied to identical parts in the several figures and in which Fig. 1 is a view in front elevation of an apparatus constructed in accordance with the invention;

Fig. 2 is'a similar view of the apparatus with added elements;

Fig. 3 is a plan view of the showing of Fig. 2;

Fig. l is a wiring diagram of the electrical control circuit;

Fig. 5 is an enlarged detail view of a portion of the switch supporting and actuating levers;

Fig. 6 is a section on the line 66 of Fig. 5;

Fig. 7 is a detached diagrammatic view of the variable speed transmission;

Fig. 8 is an enlarged detail view on the line 8-8 of Fig. 7; and I Fig. 9 is a diagrammatic view of the apparatus of Fig. 2 showing one form of driving means for the strand.

' As herein disclosed, the invention is illustrated as applied in connection with the spooling or taking up of a cable or other like strand, only so much of the related apparatus being shown as is necessary for an understanding of the invention.

Let it be assumed that a-cable i9 is being advanced longitudinally of itself from left to right in Figs. 1 and 2 by being wound upon a spool, reel, drum or other analogous rotatable take-up means or by being drawn along by a capstan l8 or other advancing means, at the right, against some resistance afiorded by :means at the left (not shown), e. g. (cable forming means of some kind. Let it 'be further assumed that the cable advancing me ns .18 .be driven by mechanical or other interconnections, e. g. shafts i1 and gears I!6,. from the (output shaft 42 of a suitable variable speed transmission device suchas that generally indicated at 40. The particular device 49 here shown is that commercially known as a Reeves variable speed transmission and is described in detail hereinafter, but any analogous suitable ,device may be used instead.

The weight of the cable, which is unsupported during its passage through the distance shown,

the cable .by means of the apparatus embodying the invention. 7

Ahorizontal lever 20, pivotably mounted on a hollow, transverse, horizontal shaft 2 I supported in a pedestal 26, carries a sheave or roller 22,

which rides on the downwardly curved free hangplate 30 to operate the switches 35 and 35 respectively and are confined in their motion between fixed stop pins under them and adjustable stop screws above them as shown. A second horizontal plate-like support or lever I30 is mounted on the pedestal 26 on a pivot I3I vertically under the shaft 2I and spaced therefrom. The support I30 is rotatable on its pivot but against frictional resistance. arms of the support I30 and respectively under the ends of the levers 31 and 38 are mechanical contact shoes I31 and I 38 to coact with the lower edges of the outer ends of the levers 3'I and 38 respectively as hereinafter described. Pawls 21 and 28 suitably mounted on depending extensions of the plate 30, are arranged to just pass the respective ends of the lever I30 when the parts are in the-normal position shown in Fig. 1. The two switches 35 and 36 are connected into the power supply circuit of the motor 52 (Fig. 4) which drives the control shaft 43 (Fig. '7) of the variable speed means 40. The switches are so connected that when switch 35 is closed, the motor 52' drives the shaft 43 to lessen the speed of the output shaft 42, while closing switch 35 causes the speed of shaft 42 to increase. The wiring diagram in Fig. 4, showing the interconnections of the switches 35 and 3B in the power supply to the motor 52, is believed to be self-explanatory and not to' need detailed description. 7

To describe the operation of the arrangement of Fig. 1, let it be assumed that the cable I9 is increment of speed at the shaft 42, pauses for a brief interval, effects another increment, pauses again as if to see if the total correction is sufficient, and so on until the sag of the catenary begins-to diminish. When the sag begins to diminish, the lever moves counterclockwise, carrying the plate 30 with it. The lever 38 is lifted clear of the shoe I38. A moment later the On the upper edges of the horizontal being advanced from left to right with its speed cable in lessened and the catenaryon whichthe The lever 20 turns member 22 is supported sags. clockwise, carrying the shaft 2I and the plate 30 with it. The lever 38 comes down on the member I38 and is moved on the plate 30 to close the switch 36. The motor 52 starts and drives the shaft 43 to cause the speed of the output shaft 42 i to increase and thus increase the speed of the advance of the cable and hence the tension in the cable. Meanwhile the lever 20 continues to turn. The pawl 28 moves below and under the corresponding end of the lever I30 while the pawl 21 moves above and away. The pressure of the lever 38 on the shoe I38 turns the lever I30. Since the pivot of I30 is below the pivot of 30, the contact edge of 38 slides inwardly along the top face of the shoe I38. The top face of each shoe I31 and I38 is transversely notched or serrated in-the manner best shown in Fig. 5. When the contact edge of 38 falls into the first of these serrations,

tor 52' stops.

As shown, conditions are prepawl 28 engages under the lever I30; and the whole returns to the status of Fig. 1. In the drawing the gap between the levers 31 and 38 and the shoes I31 and I38 respectively is exaggerated for clarity. In practise it will preferably be barely suificient .to enable the operation asdescribed with a minimum time lapse between the start of motion of the lever 20 and the responsive start of actuation of the motor 52.

It isv believed that the operation in case of an undesired "increase in tension in the cable with consequent lifting of the catenary is too obvious after the above to require detailed explanation.

As before stated, the cable advancing means (not shown) is assumed to be driven from the output shaft 42 of the device 40, while the input shaft 4! is driven by any suitable constant speed driving means (not shown). A pair ofmutually opposed cones 44, 44 is mounted on the shaft M and keyed thereto to-be freely slidable thereon but enforcedly rotatable therewith. A similar pair ofcones 45, 45 is mounted in like fashion on the shaft 42. A pair of levers 45, 46 is mounted on fixed pivots. The upper end (Fig. 3) of each lever 48 is pivotally secured to one of the cones 45 while its lower part is similarly attached to one of the cones 44 at an equal distance from its fulcrum. The lower end of each lever 46 carries a nut engaging with respectively oppositely threaded portions of the control shaft 43. The shaft 43 is drivable through a sprocket and chain drive 49 and a wheel andworm drive 50, 5| by a reversible electric motor 52. Connections to a suitable source of electric current (not shown) to run the motor in one direction or the other, are controlled by the switches and 36 respectively as indicated in Fig.4.

As described, overcorrection is obviated by the described coaction of the levers 31 and 38 with the serrated shoes I31 and I38 respectively, from which it results that the apparatus effects a partial correction, pauses momentarily, effects another partial correction, pauses again, and is completely inhibited to operate, substantially when satisfactory correction is completed.

a layer after layer is wound on. Such change occurs usually somewhat abruptly when a layer is completed and the next turn of winding is laid on the just completed layer. If, however, some cause effects a' very slow variation of tension, it may happen that, when an increment of speed of the shaft 42 is made, the new speed and tension of the cable are such that conditions are just balanced with the contact edge of the switch lever in the bottom of one of the serrations of the shoe. As the lever Zllremains then 'in its new position, and also the plates 30 and I30 with both switches open, no new speed increment is effected and the whole process remains at the new tension level thus established differing slightly from the desired level.

In cases such as that last described, recourse may well be had to the amplified form shown in detail in Figs. 2, 3, and 6. Here an upward extension 29 is attached rigidly to the middle of the plate 30 and carries a sheave 3|. A cord 32 is attached at one end to an adjustable extension on the lever 20, passes over one member of a double guide sheave 33, around the sheave 3|, around the other sheave 33, and over a guide sheave 34 to an extension 54 on the shaft 43 to which it is secured after being wound a number of times thereon. The plate 30 is not here tight on the shaft 2| as in Fig. 1, but is freely rotatable thereon and is held in the normal position shown in Fig. 2 between the spring 39 and the cord 32. The lever [30, as before, is movable against friction on its pivot I3 I.

Should the lever move clockwise, it pulls the cord 32 and thus moves the plate also clockwise with the results described above in connection with Fig. 1 where the plate turns in like manner with the shaft 2|. The switch 36 is closed and the motor 52 drives the shaft 43, thus actuating the speed control to increase the speed of the output shaft 42. However, at the same time the cord 32 is unwound from the extension 54, allowing the spring 39 to return the plate 30 and thereby also the lever I30 to the normal position, opening the switch 36 and stopping the motor 52 to annul the actuation of the control.

The control exercised primarily by the serrated shoes I31 and I38 coacting with the levers 31 and 38 respectively, is such that an incorrect tension in the cable is corrected by intermittent step by step approximation, which may fall triflingly short of full correction but cannot become excessive. The control exercised by the cord 32 primarily is such that an incorrect tension in the cable is, in practise, corrected by a trifling overcorrection which is then corrected in turn, the consequent hunting being damped out rapidly. By combining the two controls, as in Fig. 2, each serves to make good the marginal errors of the other. While either i wholly satisfactory by itself in most cases in practise, there may be a few instances where the extreme delicacy of control afforded by the combination may be preferred.

The combination of switches actuable by movement of the plate 30 under control of the cord 32 which in turn is controlled both by the lever 20 and by the extension 54, is not per se a part of the present invention, being a part of one phase of the present invention only in combination with the serrated shoe control. The cord control is described and claimed per se in copending application Serial No. 406,856, filed of even date herewith by Harry H. Merwin, and assigned to the same assignee as the present invention. Reference may be had to the said copending application for details of disclosure and description of the cord control not made wholly clear herein.

The embodiments of the present invention herein disclosed are illustrative and may be variously modified and departed from without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1 In a strand handling apparatus having means to advance a strand longitudinally and means adjustable to control the speed of advance of the strand, means responsive to variations of tension in the strand to adjust the speed control means, and means to cause the responsive means to actuate the speed control means intermittently to approximate a desired speed step by step.

2-. In a strand handling apparatus having means to advance a strand longitudinally and means adjustable to control the speed of advance of the strand, means responsive to variations of tension in the strand to adjust the speed control means, and means to cause the responsive means actuate speed control means intermittently, in combination with means actuable by the control means to annul the actuation of the control means.

3. In a strand handling apparatus having means to advance a strand longitudinally in a free hanging catenary and including adjustable variable speed transmission means to control the speed of advance of the strand and thereby the tension in the strand, a member supported on the catenary of the strand and movable thereby in response to variations in the tension of the strand, means actuable by the member to adjust the speed control means, and means interposed between the member and the adjusting means to cause the member to actuate the adjusting means intermittently to approximate a desired speed step by step.

4. In a strand handling apparatus having means to advance a strand longitudinally in a free hanging catenary and including adjustable variable speed transmission means to control the speed of advance of the strand and thereby the tension in the strand, a member supported on the catenary of the strand and movable thereby in response to variations in the tension of the strand, means actuable by the member to adjust the speed control means, and means interposed between the member and the adjusting means to cause the member to actuate the adjusting means intermittently, in combination with means actuable by the control means to annul the actuation of the control means.

5. In a strand handling apparatus having means to advance a strand longitudinally in a free hanging catenary and including adjustable variable speed transmission means to control the speed of advance of the strand and thereby the tension in the strand, a member supported on the catenary of the strand and movable thereby in response to variations in the tension of the strand, electrical switch means to adjust the speed control means, a serrated shoe to coact with the switch means to actuate the same intermittently, and means actuable by the member to cause relative motion of the switch means and the shoe to actuate the switch means.

6. In a strand handling apparatus having means to advance a strand longitudinally in a free hanging catenary and including adjustable variable speed transmission means to control the speed of advance of the strand and thereby the tension in the strand, a member supported on the catenary of the strand and movable thereby in response to variations in the tension of the strand, electrical switch means to adjust the speed control means, a serrated shoe to coact with the switch means to actuate the same intermittently, and means actuable by the member to cause relative motion of the switch means and the shoe to actuate the switch means, in combination with means actuable by the control means to annul the actuation of the control means.

7. In a strand handling apparatus having means to advance a strand longitudinally in a free hanging catenary and including adjustable variable speed transmission means to control the speed of advance of the strand and thereby the tension in the strand, a member supported on the catenary of the strand and movable thereby in response to variations in the tension of the strand, a lever movable by the member, electrical switch means mounted to be movable by the lever and actuable to adjust the speed control means, and a serrated shoe mounted to be movable by the lever to have motion relative to the switch means to actuate the switch means intermittently,

8. In a strand handling apparatus having means to advance a strand longitudinally in a free hanging catenary and including adjustable variable speed transmission means to control the speed of advance of the strand and thereby the tension in the strand, a member supported on the catenary of the strand and movable thereby in response to variations in the tension of the strand, a lever movable by the member, electrical switch means mounted to be movable by the lever and actuable to adjust the speed control means, and a serrated shoe mounted to be movable by the lever to have motion relative to the switch means to actuate the switch means intermittently, in combination with means actuable by the control means to annul the actuation of the control means.

VVALDEMAR C. EWALDSON. 4

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