US1955666A - Tension-device - Google Patents

Description

J. A. ANDERSON TENSION DEVICE April 17, 1934.

3 Sheets-Sheet 1 Filed May 4. 1932 April 17, 1934. J. A. ANDERSON TENSION DEVICE I Filed May 4, 1952 5 Sheets-Sheet 2 w n|.l llluul lvl lll IHHIIIIIIII} :um umum a El ma I I lkmfll Q a. 43M 5 I Aprii 17, 1934. J, AND R ON 1,955,666

TENSION DEVICE Filed May 4, 1932 3 Sheets-Sheet 3 if .6 7/-% nnnnnnfi 2 27 y 7 F5; 7

Patented Apr. 17, 1934 TENSION-DEVICE Johan A. Anderson, Cranston, R. 1., assignor to Universal Winding Company, Boston, Mass, a corporation of Massachusetts Application May 4, 1932, Serial No. 609,321

10 Claims.

This invention relates to winding machines for winding cops, cones and other forms of packages of yarn, thread and similar strand materials; and particularly to improved means for 6 regulating the amount or degree of tension applied to the yarn being wound .in accordance with the linear speed or rate of draft of the latter. Y

In the following specification and claims the term yarn is employed in a general sense to apply to all forms of strand material, either textile or otherwise, and the designation package is intended ,to indicate the product of the winding machine whatever its form.

One object of the present invention is to provide a differential tension-device adapted to operate automatically to maintain a uniform tension on the yarn during the winding.

Another object of the invention is to provide a device of the type specified which is controlled by the growth of the winding to act positively to reduce the applied tension on the yarn as the speed of draft of the latter increases whereby to maintain the ultimate tension uniform throughout'the winding.

Another object of the invention is to provide a device of the type specified which acts positively to control the tension applied to the yarn without the use of levers, weights or other elements liable to cause vibration or chatter of the tension-members.

Another object of the invention is to provide a device of the type specified having means arranged to act directly on one or both of the tension-members between which the yarn-feeds to progressively separate said members to efiect a progressive diminution in the tension applied to the running yarn as its linear speed increases.

Another object of the invention is to provide an improved device of the type specified which is of simple construction, direct in action and proof against derangement or getting out of order.

Further objects of the improvement are set forth in the following specification which describes a preferred embodiment of the invention, by way of example, as illustrated by the accompanying drawings. In the drawings:

Fig. 1 is an elevational viewof a winding machine unit showing the essential elements of the winding mechanism and illustrating the present improved tension-device as applied to use therewith;

Fig. 2 is an enlargedside view of the tensionr, device and differential controlling means therefor;

Fig. 3 is a plan view of the tension-device and controlling means showing the parts in position at the commencement of the winding operation; f Fig. 4 is a similar view showing the parts in their relationship to a later stage in the progress a of the winding;

Fig. 5 is' a detailed perspective view of the helical cam for regulating the adjustment of the tension-members;

Fig. 6 is a perspective view of one of, the adjusting elements for the cam;

Fig. '7 is a sectional view taken through the fingers of the tension-members and showing them' acting on the yarn to apply the maximum degree of tension at the start of the winding; and

Fig. 8 is a similar view showing the tensionfingers in more open position to apply less tension on the yam at a later stage in the winding operation. I The present invention is concerned particularly with positively-driven winding machines wherein the winding-spindle is rotated at a constant rate of speed so that during the winding of a package thereon the speed of draft or linear rate of movement of the yarn progressively increases with the increase in circumference of the wound mass. It is well known to those skilled in the art that in winding on machines of the-type specified, as the winding progresses and the package increases in circumference the yarn must feed thereto at an accelerated rate or with an increased speed of draft and, therefore-unless controlled, the tension on the rlmning yarn will be augmented or increased from this cause. It has heretofore been proposed to provide means for gradually relieving or reducing the applied tension on the yarn during the growth of the package and the present invention is distinguished from such known devices in that it provides a positive control of the tension-members rather than through the use of pivoted levers, adjustable weights and like unstable elements liable to vibration.

The invention is herein shown as applied to use on a winding machine of conventional type wherein the package is wound on a positivelydriven winding-spindle and the yarn traversed longitudinally of the axis thereof by means of a reciprocating thread-guide. Referring to Fig. l

of the drawings, 2 designates a portion of the side member or frame of a gang winding machine comprising a plurality of winding heads or units, only one of which is herein shown. It will be understood that the winding mechanisms are assembled on the frame in gangs of any suitable number with all the units of the same construction. The frame 2 may be'of substantially boxlike construction mounted on suitable legs, not herein shown, and in this form it provides a casing or housing for certain elements of the winding mechanism. The opposite sides of the frame 2 support suitable bearings in which are jou'rnaled a horizontal winding-spindle 3 and a parallel cam-shaft 4. Pivotally mounted on the camshaft 4 is a traverse-frame 5 embodying a trackway for the reciprocating thread-guide which traverses the yarn lengthwise of a paper tube, bobbin or other yarn-carrier placed on and rotated by the winding-spindle 3.

In accordance with a usual construction the thread-guide 10 is in the form of a. button-like element mounted on a blade or arm 12 which is attached at its lower end to a horizontal traversebar or rod 13. The traverse-bar 13 slides in a grooved guideway 14 formed in a horizontal cross-member 15 of the traverse-frame 5, being held in place by aguide-plate or traverse-frame back 6 formed as a part of or fastened to the traverse-frame 5 at 9. The guide-arm 12 bears against a finished face '7 on the traverse-frame back 6 and as the package builds up on the coptube .1: the guide is forced radially away from the winding-spindle 3, thereby swinging the traverse frame 5 in a clockwise direction as viewed in Fig. 1. To counterbalance the traverse-frame 5 "against the pressure of the package on the thread-guide 10 the frame is preferably provided with a counterweight 8 depending therefrom in the manner of a pendulum. As a further means for resisting the action of the package to swin the guide away from the spindle 3, differential pressure-means are attached to the counterweight 8, this latter means being later described in connection with the operation of the tensioncontrolling device forming the subject of the present invention.

The traverse-bar 13 is reciprocated in its guideway 14 on the traverse-frame 5 by any suitable means such as a cylindrical cam 16 indicated in Fig. 1. The cam 16 is of conventional type comprising a circular rim 17 supported by spokes 18 which radiate from a hub 19 mounted fast on the cam-shaft 4. The rim 17 of the cam16 is provided with a helical groove which engages a roller or follower 22 on the traverse-bar 13, these connections not being herein shown or described in detail as they are of a well known construction commonly used in the art. Suffice it to state that the winding-spindle 3 and cam-shaft 4 are connected by gearing or other suitable means to rotate in unison but at different speeds, and the cam 16 driven from the shaft 4 operates to reciprocate the traverse-rod 13 to traverse the thread-guide 10 longitudinally of the windingspindle.

A suitable dogging-device comprising a pivoted arm 20 which frictionally engages a tapered groove in an arcuate quadrant 21 acts to control the swinging movement of the traverse-frame 5 as the guide recedes from the winding-spindle 3 during the growth in the winding. The arm 20 is resiliently urged into engagement with the groove in the quadrant 21 to resist retrogressive movement of the thread-guide 10 toward the winding-spindle while permitting free movement of the traverse-frame 5 in the opposite direction.

Suitable stopping mechanism is usually provided for each winding unit to automatically control the operation of the machine, but these devices are not herein shown or described since they do not directly relate to the invention of the present application.

The yarn y or other strand material to be wound feeds through a groove 11 in the threadguide 10 and a wire thread-bail 24 is usually provided on the traverse-frame back 6, across which the strand draws as it leads from the tension-device arranged below. The tensiondevice. indicated generally by the reference numeral 25 in the present drawings, is mounted on a frame or bracket 26 bolted to a boss 2'7 on the side of the frame 2, see Figs. 1 and 3. In the embodiment of the invention as herein illustrated the tension-device 25 comprises two opposite tension-plates or members 29 and 30 which are of the type known as finger tensions. Each plate or member 29 and 30 is formed with parallel tines or fingers 31 and 32 adapted to be disposed in alternate staggered relationship to bear against the running yarn to cause it to follow a more or less sinuous course whereby to provide resistance to its draft. The tension-plates 29 and 30 are mounted on the tension-bracket 26 by means of a vertical rod 33, one tension element being preferably fixed and the other pivoted on the rod to adapt the latter to swing toward and away from the fixed member to vary the relationship of the tension-fingers and thereby con-' trol the degree of sinuosity or. undulation in the course of the yarn feeding therebetween. The tension-bracket 26 reaches outwardly from the side of the frame 2 and is provided with upper to project at right-angles from its plate portion,

the ears being pierced with holes for receiving the rod. A screw 40, see Figs. 2, 3 and 4, is inserted through a hole in the plate portion of the tension-member 29 and screwed into an ear or lug 41 on the tension-bracket 26 to hold the member 29 in fixed position.

The opposite, movable tension-member 30 is pivoted on the rod 33 by means of arms 42 and 43 bent at right-angles to its main plate portion and pierced to receive the rod. The two arms 42 and 43 on the tension-member 30 are of generally triangular shape in plan view, as shown most clearly in Figs. 3 and 4, and each arm is provided with a rolled forward edge or upwardly bent lip 44 which acts as an abutment against which the yarn is adapted to bear to prevent it from sliding rearwardly through the tensionelements. That is to say, the yarn is adapted to draw across the faces of the lips 44 to position it between the tension-fingers and prevent it from getting out of place.

The rearward inclined edge 45 of the upper arm 42 of the tension-member 30 is provided with a bearing surface adapted to be engaged by the controlling means which acts to position the tension-members one with respect to the other to control their action on the yarn. As shown in Figs. 1, 3 and 4 the bearing edge 45 is reinforced with a rounded element 46 which may comprise a short length of rod slitted to receive the edge of the arm and soldered or brazed thereto. The tension- fingers 31 and 32 of the two members 29 and 30 are preferably stamped or shaped in concavo-convex form as indicated in Figs. '7 and 3 of the drawings to provide rounded surfaces for contacting with the yarn. Referring to Fig. 3 of the drawings, the opposite ends of the fingers may be further formed with rounded protuberances 28 which serve as abutments to further define the course of the yarn across their convex faces and prevent it from whipping out from between the fingers. In accordance with a preferred form of construction the outer ends of the tension- fingers 31 and 32 are connected by integral strips 4'7 and 48 to provide a grid-like structure for each of the tension-members. The two end strips 47 and 48 are bent or fiaredoutwardly at an angle to each other whereby they provide a sort of trough or reentrant guideway for directing the yarn into place between the fingers 31 and 32 when it is drawn upwardly through the trough. As a further means for guiding the yarn into position between the tensionmembers 29 and a wire guide 49 having a vshaped or reentrant opening is fastened to the bottom of the tension-bracket 26.

The present drawings illustrate a yarn-cleaner or slub-catcher 50 attached to the top of the tension-bracket 26 above and in line with the tension- fingers 31 and 32, but as this device forms no part of the present invention it will not be further described. Suffice it to state that an opening is provided between a rod 51 and a plate 52 through which the yarn y passes as it feeds to the thread-guide 10.

The movable tension-member 30 which, as be fore noted, is pivoted on the rod 33 may be maintained in cooperative relation with the fixed member 29 .by any suitable means such as a weight or spring. In the present embodiment of the invention the movable member 30 is provided with an arm 54 extending rearwardly from its plate portion with its end in position to be operated upon by a spring-pressed plunger 55. The plunger 55 is mounted to slide in a bore 56 in a cylindrical lug 57 on the side of the bracket 26. The plunger 55 is formed with a reduced shank-portion around which is coiled a helical spring 58 pocketed in the bore 56, the spring tending to force the plunger outwardly to act on. the arm 54 to swing the tension-member 30 to close the tension-fingers together. The swinging movement of the tension-member 30 under the action of the springplunger 55 is limited by the engagement of the trough portions or vertical strips 47 and 48 on the tension-membersas the fingers 31 and 32 pass by each other.

It has been previously stated that pressure is applied to the traverse-frame 5 to resist its swinging movement as the thread-guide 10 is forced outwardly from the axis of the windingspindle 3, the purpose being to cause the threadguide to bear against the package at all times during the winding whereby to insure the laying of the coils of yarn accurately in position and to compact the mass to produce a firm stable package. It is a well known principle that the resistance to the receding movement-of the guide should'be greatest at the start of the winding when the package is smalland decreasegradually as the diameter of the package increases so as not to result in excessive pressure which might cause bulging of the wound mass at its ends. For this purpose of reducing the resistance to the movement of the thread-guide various forms of differential pressure devices have been provided frame member 2 and its rearward end carries a crank-arm 63 secured fast on its reduced portion by means of a nut 64. The crank-arm 63 has a series of screw-threaded holes 65 into one of which is screwed the bent end 66 of a connecting rod 6'7 having its opposite end 68 bent around and hooked through a hole in a lug 70 projecting from the side of the counterweight 8 of the traverse-frame 5. It will be vobvious that as the thread-guide 10 moves away from the windingspindle 3 with the growth of the winding and the counterweight 8 swings in a clockwise direction the link or connecting rod 6'7 will act to turn the crank-ar'm 63 in a clockwise direction as viewed in Fig. 1. By adjusting the end 66 of the connecting rod 67 in the different holes 65 a greater or less movement of the crank-arm 63 and the shaft 61 may be effected.

Fast on the rod or shaft 61 in abutting relation with the boss 62 on the frame 2 is a hub-member 71 which carries the weight-arm 60. The member '71 may be secured fast on the rod pr shaft 61 by a set-screw 69 or any other suitable means. The member 71 is formed with a forwardly-projecting hub 73 on which an annular portion '74 of the weight-arm 60 is rotatably mounted. The weightarm 60 is formed with anarcuate slot '75 for receiving a screw '76 screwed into an arm 77 on the mounting member 71. Through this means the arm 60 may be adjusted rotatably about the axis of the member 71 to regulate its initial position at the start of the winding. The outer end of the arm 60 is formed with a series of notches 78'into which may be hooked a headed pin or stud 79 projecting from the side of a weight 80 to suspend the latter in different positions on the arm. A hairpin-shaped wire 81 is received in suitable holes in the end of the arm 60 with its longer portion reaching across the top of the openings '18 and held in a hole in the inner portion of the arm, the wire servingto hold the weight 80 in place on the arm. It will be understood from the foregoing that as the thread-guide 10 recedes from the winding-spindle 3 and the traverse-frame 5. is swung in a clockwise direction the. link 67 will move the crank-arm 63 whereby to rotate the shaft 61. As the shaft 61 is rotated in this manner the weight-arm 60 is swung upwardly to reduce its leverage and thereby the pressure applied by the weight 80 to resist the swinging movement of the traverse-frame.

In the'present embodiment of the invention the shaft 61 is employed as an intermediate element actuated from the transverse-frame 5 to operate the means for controlling the tension on the yarn. It is to be understood, however, that any other suitable moving element actuated during the progress of the winding may serve as the operating means for the tension-controlling means. Referring to Figs. 3, 4 and 5 of the drawings, in the present preferred form of construction, the means for adjusting the movable tension-member 30 with respect to the fixed member 29 consists in a cam 85 mounted on the shaft 61 and having a substantially helical face 86 which engages against the bearing-element 46 on the arm 42 of the tension-member 30. As

shown most clearly in Fig. 5 of the drawings the cam 85 is preferably constructed in the form of 86 is a shorter inclined face 89 of greater inclination which completes the circumferential rim of the cam.

The cam-disk or member 85 is preferably mounted on the shaft 61 to adapt it for adjustment angularly of the axis .thereof to provide for setting the edge of the rim of the disk in contact with the bearing-member 46 when the traverse-frame 5 is in its initial position with the thread-guide 10 against the surface of the cop-tube a: on which the package is to be wound. The winding machine is usually provided with means for holding the cop-tubes of varying diameter and therefore the adjustable arrangement of the tension-control cam 85 is convenient for setting the cam to provide for the proper degree of tension on the yarn at the start of the winding. As a simple and convenient means for adjustably mounting the cam-disk 85 on the shaft 61 I provide a series of serrations 90 nadiating from its axial hole 91 and adapted to engage corresponding serrations on the face of a disk or washer 92 fastened to the end of the shaft. The disk or washer.92 is secured to the end of the shaft 61 by means of an axial screw 93 and the cam-disk is rotatably mounted on the shaft to be held with its serrations or teeth in engagement with the serrations on the washer by means of a helical spring 94 encircling the shaft and bearing against the hub 73 of the member 71. Through this arrangement the cam-disk 85 may be rotated on the shaft 61 with its teeth 90 acting as a ratchet in cooperation with the teeth on the washer 92'. After the cam-disk 85 has been adjusted with the edge 86 of its flange 8'7 engaging the bearing element 46 on the arm 42 on the tension-member 30 the ratchet-teeth act to hold the disk fast with the shaft 61. As the shaft 61 is rotated from the movement of the traverse-frame 5 during the recession of the thread-guide 10 from the windingspindle 3 the cam-disk 85 is turned to cause its helical face 86 to move the arm 42 on the tension-member 30 to shift the latter from closed position as illustrated in Fig. 3 to a more open position as shown in Fig. 4. The method of operation of the complete device is as next explained.

The winding machine is prepared for operation by drawing the strand of yarn y from its supply upwardly through the tension-device 25, thence through the slot in the slub-catcher 50, from which point it is led across the threadbail 24, through the groove 11 in the threadguide 10 and its end attached to the tube a: on

' the winding-spindle 3. At the start of the windwhen the two tension-members 29 and 30 are I in closed relationship, that is, with their tension- fingers 31 and 32 assuming a position of substantial vertical alinement as illustrated in Fig. '7. With this setting of the device the strand of yarn y draws between the tension- fingers 31 and 32 in such manner as to direct it in a course of maximum sinuosity. it being understood that the plunger-pin 55 acts on the arm 54 of the the other. Between the ends of the helical edge tension-member 30 to maintain the latter in closed position with respect to the fixed member 29.

The operation of the machine is started to effect rotation of the winding-spindle 3 whereby the yarn is wound on the cop-tube :r and traversed longitudinally thereof by the reciprocating thread-guide 10. As the mass of yarn builds up on the tube a: it forces the thread-guide 10 radially away therefrom as indicated by the dashlines in Fig. 1 of the drawings, the traverseframe 5 being swung on the shaft 4 as a pivot under this action. As the traverse-frame 5 swings in a clockwise direction it draws the crank-arm 63 downwardly to raise the pressure lever 60 whereby to gradually reduce the force of the weight 80 in resisting the outward movement of the thread-guide 10 awayfrom the axis of the package.

During the turning of the shaft 61 under the action of the crank-arm 63 the cam-disk 85 is rotated in a clockwise direction as viewed in Figs. 1 and 2. The rotative movement of the cam-disk 85 causes its helical face 86 to ride on the bearing-member 46 to swing the arm 42 forwardly as viewed in Figs. 3 and 4, thereby causing the tension-member 30 to be swung on its pivot-rod 33 to gradually shift its fingers 32 with respect to the fingers 31 on the fixed member 29. The effect of this action is clearly shown in Figs. 7 and 8 of the drawings, the change in the relationship of the tension- fingers 31 and 32 serving to provide a straighter course for the strand of yarn y whereby as its sinuosity is reduced it will feed through the tension-device with less resistance, that is with less tension applied thereto. In this way the tension applied to the yarn is gradually diminished as the winding increases in diameter in accordance as required by the increase in the lineal rate of movement or speed of travel of the yarn through the tension-device.

It will be observed from the foregoing that the present invention provides a particularly simple yet ingenious means for positively controlling the relationship of the tension-members during the III crates automatically to maintain a substantially constant and uniform tension on the yarn from start to finish of the package. The yarn being thus wound under uniform tension, a more perfeet and properly formed package is produced without danger of excessive compression in the outer layers tending to bulge and break down the,

ends of the wound mass.

As a particular feature of improvement in the present invention the adjustment of the tensionmembers is effected positively by direct engagement with one of said members in opposition to the pressure which maintains the members closed. Through this arrangmeent all liability of vibration or chattering of the tension-members, a source of trouble with previously used devices, is entirely eliminated whereby to avoid any fluctuations in the applied tension to the yarn.

While the invention is herein shown and described as embodied in a preferred form of construction, it is to be understood that modifications may be made in the structure and arrangement of the parts of the device and in the method of applying it to use without departing from the spirit or scope of the invention. Therefore, without limiting myself in this respect, I claim:

1. ma winding machine, the combination of a tension-device for tensioning the yarn feeding to the package, and a movable member having a cam-face inclined obliquely to its direction of movement and arranged to act on the tensiondevice to reduce the amount of tension applied to the yarn as thelinear rate of feed of the latter increases.

- 2. In a winding machine, the combination of a tension-device for applying tension to the yarn feeding to the package, a cam having a face inclined obliquely to its direction of movement and arranged to act on the tension-device to reduce the amount of tension applied to the yarn, and means for moving said cam.

3. In a winding machine, the combination of a tension-device for applying tension to the yarn feeding to thepackage, a rotatable cam having a face inclined in the direction of its axis and arranged to act on the tension-device to reduce the amount of tension applied to the yarn, and means for rotating the cam.

4. In a winding machine, the combination of a tension-device comprising opposite members adapted to bear against the yarn as it feeds to the package being wound, a helical cam arranged to separate the tension-member to reduce the amount of tension applied to the yarn, and means to operate the cam.

5. In a winding machine, the combination of a tension-device comprising opposite members adapted to bear against the yarn to apply tension thereto, a rotatable cam having a helical face arranged to act to separate the tensionmembers to reduce the tension applied to the yarn, and means to rotate the cam.

6. In a winding machine, the combination of a tension-device for applying tension to the yarn feeding to the package, a helical cam operative on the tension-device to reduce the amount of tension applied to the yarn, and means to operate the cam.

'7. In a winding machine, the combination of a tension-device comprising opposite members adapted to bear on the yarn to apply tension thereto, a rotatable member having a helical cam-face on its side engaging with one of said tension-members to cause it to move the latter to -vary the amount of tension applied to the yarn,

and means actuated concurrently with the increase in diameter of the winding to rotate the cam-member.

8., In a winding machine, the combination of a pair of tension-members adapted to bear against the yarn to apply tension thereto, a rotatable member having a cam-face disposed helically of its axis and adapted to bear against one of said tension-members to move it with respect to the other member to reduce the tension applied to the yarn, and means actuated concurrently with the growth in the winding to operate the cam.

9. In a winding machine, the combination of a tension-device comprising a relatively fixed element and an element movable toward and away from the fixed element to bear upon the yarn drawing therebetween, a cam' having a helical face engagingagainst the movable element, and means operative during the growth of the winding to move the cam to shift the movable tension-element to progressively reduce the amount of tension applied to the yarn.

10. In a tension-device, the combinationof a tension-member adapted to bear against a running yam to apply tension thereto, a helical cam engaging said tension-member to displace it to vary the amount of tension applied to the yarn,

and means for continuously operating said cam.

11. In a tension-device, the combination of a pair of tension-members relatively movable one with respect to the other, a rotatable cam having a helical face acting upon one of the tensionmembers to move the latter, and means for rotating the cam.

12. In a tension-device, the combination of a pair of tension-members, arranged in opposite relationship to bear against a yarn drawing therebetween, one of said tension-members being movable relatively to the other member to vary the amount of tension applied to the yarn, a cam having a helical face engageablewith the movable tension-member, and automatically-operated means for rotating the cam.

13. In a tension-device, the combination of a pair of tension-members arranged in opposite relationship to bear against a yarn drawing therebetween, resilient means for maintaining said tension-members in cooperative position to act on the yarn, a cam having a helical face acting against one of said tension-members to move it with respect to the other member to vary the amount of tension applied to the yarn, and means for automatically operating said cam.

14. A tension-device comprising a tensionmember adapted to bear against a yarn drawing thereacross, a rotatable cam having a helical face engaging the tension-member to adapt it to displace said member to vary the amount of tension applied to the yarn, means for rotating the cam, and means for adjusting the position of the cam with respect to its rotating means.

15. A tension-device comprising a pair of ten- 11? sion-members adapted to bear against a yarn drawing therebetween, a rotatable cam having 'a helical face engaging one of the tension-members to shift it with respect to the other member to 115 teeth, a shaft for rotating the cam, a collar fast on said shaft and provided with teeth adapted to engage the teeth on the cam, and means forresiliently maintaining the teeth on the cam and collar in engagement.

17. In a winding machine, the combination of a shaft, a cam on said shaft provided with a helical face, a tension-device having relatively movable members adapted to bear against a yarn, and means engaging the face of thejcam and moved therefrom to change the relative position of the tension-members to reduce the tension applied to the yarn.

18. In a tension-device, the combination of opposite members adapted to bear against a yarn drawing therebetween, one of said members being movable with respect to the other member to vary the amount of tension applied tothe yarn and said movable tension being provided with an arm, a disk-like cam having a circumferential rim formed with a helical face adapted to bear against the arm on the movable tension-member to change the position .of the latter, and means for rotating the cam.

JOHAN A. ANDERSON.

Images