US2404850A - Driving and stopping mechanism for sewing machines - Google Patents

Description

July 3, E$4fi 1 g, 1,, H- 2,44,50

1 DRIVING AND STOPPING MECHANISM FOR SEWING MACHINES I Filed 001:. 15, 1945 4 Sheets-Sheet 1 y 9% c. L. KNOTT 2 404 21;

'DRIVING AND STOPPING MECHANISM FOR SEWING MACHINES Filed Oct. 15, 1945 4 Sheets-Sheet 2 y 19746; .c. L. KNOTT 2,404,850

DRIVING AND STOPPING MECHANISM FOR SEWING MACHINES Fil ed Oct. 15, 1945 4 Sheets-Sheet s M 3@, 129% km mm wa DRIVING AND STOPPING MECHANISM FOR SEWING MACHINES Filed 091:. 15, 1943 4 Sheets-Sheet 4 Patented July 30, 1946 DRIVING AND STOPPING MECHANISM FOR SEWING MACHINES Clyde L. Knott, Beverly, Mass, assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Application October 15, 1943, Serial No. 506,319

Claims.

stopping mechanisms and is hereinafter illustrated as embodied in a heavily constructed shoe sewing machine of the type disclosed in an application for United States Letters Patent Serial No. 194,594, filed in the name of the present inventor on March 8, 1938, now Patent No. 2,362,649, granted October 26, 1943, in which the main shaft is driven positively at a lower speed while the machine is being brought to rest than during sewing, the lower speed of the main shaft being such that the reduction in speed will enable the shaft readily to be stopped at a predetermined position with the stitch forming devices free of the work operated upon.

In certain types of driving and stopping mechanisms, particularly for shoe sewin machines, it is convenient to provide a drive shaft having a clutch thereon actuable by lengthwise movement of the drive shaft and, as a means for connecting the drive shaft with other rotating parts, there is provided a helical or spiral gear on the drive shaft meshing with a corresponding gear on a second adjacent shaft, the driving reaction of the inclined teeth on one gear tending, under some circumstances, to thrust the teeth on the other gear axially and to move the drive shaft lengthwise in a direction which will prevent disengagement of the clutch. Also, the mechanism for driving the sewing shaft of such a machine at lower speed before bringing it to rest, includes a radially out timing cam connected to a low speed braking clutch member and a follower engaging the cam at one side of the shaft on which it is slidably mounted to throw the lower speed driving mechanism into operation. The cam follower is coupled automatically at the end of an operation to a yielding slide which acts to resist movement of the follower, thereby causing the low speed braking clutch member and cam to be moved bodily along the shaft toward its cooperating clutch member and the speed of the shaft to be reduced and then the shaft to be driven through a predetermined portion of a rotation. After being driven through a predetermined portion of the rotation, the cam moves the clutch member out of engagement with its cooperating clutch member and the shaft is brought to rest. The speed of rotation at the lower speed thereafter is insufficient to cause the shaft 'to be rotated beyond a predetermined stop-' ping position so that the machine may be stopped accurately in proper stopping position and with the smallest possible delay.

Due to the arrangement of the radially cut z j timing cam and the follower engaging the cam at one side of the shaft, the sliding movement of the cam on the shaft may be impeded to some extent by frictional resistance produced as a result of unsymmetrical application of the pressure between the cam and the follower. Also after the parts have become worn, the resulting looseness may affect adversely an even application of pressure throughout the area of the clutching surfaces between the low speed braking clutch members. Where uneven braking and clutching pressures exist between clutchingsurfaces, these surfaces when in use show indications of excessive wear and the driving power of the clutch is substantially impaired within a short time after'the clutchis adjusted to take up looseness from wear. Y

It is a general object of the present invention to provide a driving and stop-ping mechanism for a heavily constructed shoe sewing machine in which the difliculties above referred to are avoided and the operation and construction of which, are substantially improved. A further object of-the invention is to prevent the reaction of a helical gear drive connection between adjacent rotating shafts, one of which is movable lengthwise and carries a clutch member thereon, from affecting the disengagement of the clutch adversely and to provide a controlling arrangement for such a drive connection in which the driving reaction will improve the ease of control and the effectiveness of the clutch.

Other objects are to simplify and improve the construction and mode of operation of a'low speed'braking clutch in a driving and stopping mechanism to secure the greatest possible efficiency with the clutching surfaces employed and to reduce the likelihood, even after excessive wear, of uneven pressures between the clutching surfaces or of improper movements of the clutch l members toward and from each other.

In the attainment of these and other objects, one feature of the invention is embodied -in a driving and stopping mechanism having adrive shaft, a clutch actuable by movementlengthwise of the shaft, manuallyoperable means for controlling the clutch pressure, and a helical ear transmission connected to the'shaft and formed with teeth inclined to the axis of the shaft in a direction tending to throw the clutch out of operation while a load is being imposed on the transmission so that an accurate and smoothly responsive manualcontrol of the clutch pressure may be obtained. This construction and arrangement enables the rotation of the shaftrto driver.

be controlled effectively at all times and the clutch to be engaged and disengaged readily so long as the parts are rotating idly. As soon as a load is applied to the helical gear transmission, there is a tendency to separate the members of the clutch or to cause the clutchto slip, depending upon the force applied to move the shaft lengthwise. Also, there is no reaction of the helical gear transmission to prevent disengagement of the clutch members either when it is desired to bring the machine to rest or, instarting the machine, to cause a sudden uneven engagement of the clutch. In. the particular constructionhereinafter described, one clutch mem clutch plate beyond a neutral position between said clutch members and thereby to hold it out of driving relation with both; clutch members.

Another feature of the present invention redates to the use ofthrust means engaging a radial surface on a low speedbraking clutch member having a radially cut cam for throwing the .clutch member into and out of operation, said thrust means being located at the side of the main shaft supporting the clutch member opposite from -a follower engaging the radially cut-cam to equalize the pressure throughout the area of the clutching surfaces between the clutch member and its 1 Thus, the highest possible driving force is obtainable with minimum areas of clutching surfaces, the surfaces being pressed together uniformly throughout their extent and not with greater pressure along one portion than another In this way, excessive wear is avoided on the clutching surfaces when under heavy pressure, and when the surfaces-are underrelatively light pressure, they are effective to produce a maximum'possible rotational force in the main shaft on'which the clutch members are mounted. In

- accordance-with this feature, the follower engaging the cam is coupled to a yielding slide to cause the clutch member to engage its driver, and the tion with the accompanying drawings, in which Fig. 1 is a view in side elevation, partly brokenaway of a highspeed heavily constructed shoe sewing machine having a driving and stopping mechanism embodying the features of the present invention;

.If'ig. 2 is a right side view, partly in section and partly broken away, of the portion of the machine including the driving and stopping mechanism taken in a plane passing through the main sewing shaft for the machine and through the drive shaft;

Fig. 3 is a detail view illustrating the same parts of the machine taken in vertical section at right angles to the section of Fig. 2;

; Fig. 4 is a plan view of a portion 0f the low -speed driving mechanism on themain shaft of.-

the machine;

Fig. 5 is a view in side elevation and partly in section of the drive shaft, illustrating the positions of the parts while the machine is operating at high speed; and

Fig. 6 is a similar View illustrating the positions of the parts while the machine is operating at intermediate speed.

The machine herein illustrated is the same except as hereinafter described as that disclosed in the patent application above referred to and is a heavily constructed shoe sewing machine having a sewing head 2 which is mounted upon the upper end of a frame 4 of generally rectangular vertical section connected to a base 6 of similar shape. The machine is driven by an electric motor 8 carried, at the rear of the base 6 through connections including a belt Ii) passing about a pulley 12 fast to an intermediate drive shaft 14 for the main driving means of the machine. The

main driving means is connected by .a pair of pulleys l6 and IS on the shaft l4 about which are carried beltszfi and 22, respectively, extending to pulleys 24 and 2B, fast to a main. sewing and operating shaft 28 (see Figs. 1, 2,3 andfl); i The devices operated by the main shaft 28: comprise the sewing instrumentalities ofa heavily constructed McKay type machine. including r a straight hook needle 30 and a looper for thread ing the needle contained within a rotatable shoe supporting horn 32 mounted on the mainframe 4 of the machine: The main driving means. acts,

'upon depression of. a control treadle 34; mounted in the base 6, to connect the continuously rotat- 7 ing motor with the main shaft 23v and, upon release of the treadle,-a.low speed driving and braking mechanism is thrown into operation,

first, to actas a brake in reducing the speed of the sewing shaft 28 and, then, to drive the sewing shaft until a predetermined position, of the shaft is reached with the needle disengaged fromthe work.- The. main driving means comprises clutches formed bylthepulleys l6 and, I8 whichare ro- -tatable onthe shaft l4 and a central clutch plate 36 secured to the shaft l4 and disposedibetween the pulleys l6 and I8. .The shaft I4 is so mounted as to be capabl of slight longitudinal movement,

and the clutch plate 36is provided-at opposite sides with facings 38 the surfaces of which cooperate with flanges formed onthepulleys I6 and .l 8

'so'that, when the shaft Mslides longitudinally,

the plate 33 will be forced into driving relation with one or the other of the pulleys. The pulleys l6 and I8, 24 and. 26 have difierentdiameters so that the belts 20 and 22 will cause the operating shaft 28 to rotate at different speedsfwhen lone clutch or the other is closed.

The low speed driving and braking mechanism is mounted on themain sewing and operating shaft 28 and is similar to that disclosed in United States LettersPatent No. 1,099,328, granted June 9, 1914, upon an application ofLaurence E, Top]- ham andNo. 1,298,758, granted April 1, 1919,,upon

an application of William 0. Meyer, which have a low speed worm wheel similar to that indicated at 40 rotatable on the-operating shaft. The worm wheel 40 is" driven through a worm 42 secured to a cross shaft provided at its outeriend with'a pulle 46. The-worm wheel has an inner conical clutching surface arranged to cooperate" witha correspondingly shaped surface on a movable clutcnmember 48 rotatable with but slidable along the operating shaft 28 The hub'of the movable clutch memberis provided with] a. radially cut timing cam slot 50 in which a cam follower 152 rides so that the cam follower is vibrated continuously along the operatmg shaft while the machine is running. The cam follower 52 is mounted on one arm of a vibrating hell crank 54 fulcrumed on a stud 56 secured in the head 2 of the machine, and another arm of the bell crank has an elongated recess or slot into which the upper end of a vertical lock bolt or pin '58 may enter to couple the bell crank to a horizontally movable carrier or slide 6!) for the lock bolt 58, the lock bolt being spring pressed up wardlyinto engagement with the recess in the vibratin bell crank 54. The carrier 60 is acted upon by a spring 62 coiled about one end of a threaded rod 64 projecting from the carrier 60. The spring 6.2 extends beyond the end of the rod Bland surrounds the end of a bolt 66 spaced from the end of the rod 64 and secured in th head 2 of the machine, thus urging the carrier 6!! yieldingly toward the right of .Fig, 3. The rod 64 car-- .ries check nuts 68 for compressing the spring 62 andfor limiting the expansion of the spring when the check nuts come into engagement with the side Portion of the head 2 in which the carrier slides. When the lock bolt 58 enters the recess in the bell crank 54., th bell crank is restrained from vibration and the cam slot 50 causes the follower 52 to press the movable clutch member 48. into engagement with the worm wheel All for a predetermined part of a rotation. When the I speed of the main shaft 28 is substantially reduced by the braking effort of the clutch, the clutch member 48 is disengaged from the worm wheel 49 and the main shaft brought to rest, the rotation of the worm wheel being at such a low speed that the momentum of the, main shaft is quickly overcome by friction.

For driving the pulley 46 of the low speed driving and braking mechanism, there is a belt T0 surrounding the pulley 46 and a continuously rotating pulley 12 secured to the outer end of a shaft 14 supported in suitable bearings, the axis of which shaft passes at right angles to the intermediate drive shaft M. The shaft M is driven by means of helical gears 15 and 18 made fast respectively to the drive shaft I4 and th shaft is.

When the treadle 34 is first depressed with the machine at rest, the lock bolt 58 is withdrawn from engagement with the bell crank 54, thus rendering the low speed driving and braking mechanism inoperative and, b the same movement of the treadle, the clutch plate 36 is pressed into frictional engagement with the pulley I6, as illustrated in Fig. 6, to drive the main shaft. When the treadle is depressed further, the clutch plate is disengaged from the pulle l6 and forced positively against the driving pulley l8, as indicated in Fig. '5, against the force of a spring H by power actuated mechanism 19 driven by the helical gear '18, described more fully in the application referred to, so that the main shaft 28 will be rotated at a higher speed. While the machine is at rest, the spring 1! retains the clutch plate 35 out of engagement with the pulley. l8.

The treadle connections for moving the drive shaft I4 longitudinally act directly and include a vertical link 80 (see Fig. 1), a three-armed lever 82, and a horizontal rod a l connecting the lever with a forked shifting lever 88 having pins en gaging the collar 88 on the driv shaft I4. These connections are effective to shift the shaft 14' longitudinally and to bring the clutch plate against the pulley IS with the desired pressure. as shown in Fig. 6, but, when a sudden load is imposed on the helical transmission gears 15, 18,

unless the inclination of the gear teeth is in the proper direction with respect to the axis of the shaft, there a tendency to move the shaft and the clutch plate 36 forcibly with a substantial impact against the pulley Hi, thereby interfering with the proper control of the machine and preventing the clutch from being disengaged from the polic it when it is desired to reduce the speed or disengage the clutch plate 35 wholly from the pulley I 6, as in Fig. 2.

According to a feature of the present invention, the angular relation of the inclined teeth on the gears TB and 18 to the axis of the drive shaft is so arranged that "the only reaction on the shaft when a sudden load is imposed on the gears, is in a direction to move the clutch plate away from the clutching surface of the pulley 'lfi throw the low speed clutch out of operation. Thus, there is no opportunity for the low speed clutch 36., IE to act erratically. during engagement, to grab or to remain in engagement when it is desired to disengage the plate from the pulley l6.

To prevent the reaction of the helical gears 16 and 18 from forcing the clutch plate 3:6, after being disengaged from the clutching surface of the pulley it, against the clutching surface "of the pulley It, the endwise movement of the gear '16 is limited by an and thrust bearing on the frame 4, as shown in Fig. 5. In order that the drive shaft 14 and the clutch plate 36 may be moved to drive the pulley IB, the helical gear 16 is slidingly mounted on the shaft l4 and is .provided with a key :92 loosely fitting a keyway in the shaft I 4, and the shaft is formed with a shoulder as against which the gear iii presses to disengage the clutch from the pulley t6 and to maintain the plate in a neutral position between the clutch pulleys l6 and [8 out of driving engagement with either one. A suitable clearance space 96 is provided between the gear and. the bearing portion of the frame 4 in which the shaft l4 rotates at the side of the gear 16 opposite the thrust bearing .90. Thus, the clutch plate 36 and its supporting drive shaft l4 may be shifted to engage either of the clutch members consisting of the pulleys Hi and i8 and may be disengaged without any substantial resistance being offered to their movements by the transmission comprising the helical gears i5 and I8.

The location of the cam follower 52 at one sid of the main shaft 28 causes one portion of the movable clutch member -48 to be pressed with greater force than another against the worm wheel 4E! particularly when the parts become worn and excessive locseness exists between the bearin surfaces of the clutch member 48 on the main shaft 28. Also, the application of pressure by the follower 52 on the cam 59 at one side of the center of rotation produces a tilting movement of the cam on the shaft 28 about an axis transverse. to the shaft 28 in such a way as to increase the frictional resistance against sliding movement of the clutch member 48 on the shaft toward and from the clutch member 48 at the opposite side or the shaft 28 from the cam follower 52. When the lock bolt 58 couples the lock bolt carrier to the bell crank 56, the carrier 6!! is moved slightly as the clutch member 48 is pressed against the worm wheel, and this slight movement is sufiicient to transmit acorresponding movement to the lever 98 which is fulcrumed on a pin I 04 secured in the sewing head 2 of the machine. For transmitting movement to the lever 98, an arm'of the leverslidingly receives a pinjlflt around which is coiled a compression spring 'I 08 acting at one end against the arm of the lever 98 and at the other end against a shoulder on the carrier 60. The pin I06 is fixed at one end in the carrier 60 and has at the other end a pair of check nuts I ID for limiting the movement of the lever 98 under the force of the spring I68. During normal sewing operations when the lock bolt 58 is disengaged from the bell crank 54, the checknuts hold'the thrust lever 98 in a. position with the roll'lllll disengaged from thesurface I02. The arrangement is such that the'lever 98 will move the roll I against the surface I02 as soon as the roll 52 on the bell crank begins to press the clutch member towards the worm wheel 40. Since the roll I80 engages the surface I02 at a greater'distance from the center of the shaft 28 than the point of contact of the .cam roll 52 with the cam slot 59, the spring I 08is so constructed that its pressure together with the pressure of the spring 62 will be inversely proportional to the ratio of the distances between the cam follower52 and the center of the shaft to the roll I00 and the center. of the shaft. In this way, the forces applied by the-follower 52 and the roll I00 will exactly balance each other about the shaft 28 as a center, and the pressure of the clutch member 48 on the worm wheel 40 at either side of the shaft will be equalized.

fastened at diametrically opposite points onthe outer surface of the shaft.

For convenience in construction and operation,

the lock bolt is actuated through connections acting to withdraw. the lock bolt from the bell crank 54 immediately during the first part of the down- I ward depression of the foot treadle 34. These connections include a rod H6 pivotally connected between the lower end of the lock boltand a lever I'I8 fulcrumed on a stud !20, a cam lever I22 fulcrumed on a screw I24 having a cam surface engaged by a roll I26 on the lever H8 and a rod I28 pivotally connected between the cam lever and an arm of the treadle actuated lever 82.

The nature and scope of the invention having been indicated and a specific embodiment thereof having been described, what is claimed is:

. 1.A driving and stopping mechanism having,

of operationwhen the shaft is moved to release the clutch pressure witha load imposed on the transmission. v g

3. A driving and stopping mechanism having, in combination, a shouldered'drive shaft, a clutch 'actuable by lengthwise movement of the" shaft, manually operable means for controlling l the lengthwise position of the shaft, a transmission comprising a helical gear slidable on but mounted to rotate with the shaft, the teeth of said gear being cutat an inclination to the axisof the shaft to 'cause the clutch to be throwntoutof operation when the shaft is moved to release the clutch pressure with a load impose'donthe transmission, and'a thrust bearing for said helical gear for preventing lengthwise movement of the shaft after the clutch is rendered inoperative.

4. A driving and stopping mechanism having, in combination, a drive shaft, a pair of clutch members rotatable on the shaft, a central clutch plate between the clutch members, means for shifting the shaft lengthwise to press the clutch plate against either of said members, a transmission comprising a helical gear slidable onbut mounted to rotate with theshaft, the teeth on said gear being cut at an inclination to the axis of the shaft to cause the shaft to move the clutch plate under reaction of load'on the transmission away from one of said pair of members when the pressure of the clutch plate on said one clutch member is relieved, and an end thrust bearing for said helical gear for preventingthe shaft from being moved by said gear beyond a neutral position between said clutch members.

. 5. A driving and stopping mechanism having,

in combination, a drive shaft, a pair of clutch members rotatable on the shaft, a centralclu tch plate between the clutch members, means for shifting the shaftlengthwise to press the clutch plate against either of said members, a transmission comprising a helical gear slidable on but mounted to rotate with the shaft, the teeth'on said gear being cut at an inclination to the axis of the shaft to cause the shaft to move the clutch plate under reaction of load on the transmission awayfrom one of said pairkof members when the shaftis moved to release the pressure of the a clutch plate'on said one clutch member, an end in combination, adrive shaft, a clutch actuable by movement lengthwise of the shaft, manually operable means for controlling the clutch pressure, and a helical gear transmission connected toxthe shaft and formed with teeth inclined to the axis of the shaft in a direction to throw the clutch out of operation when the clutch pressure is partially released with a load imposed on the transmission.

2. A driving and stopping mechanism having, in combination, a shouldered drive shaft, a clutch 'actuable by lengthwise movement of the shaft,

manually operable means for controlling the lengthwise movement of the shaft, and a transmission comprising a helical gear slidable on but mounted to rotate with the shaft, the teeth of said gear being cut at an inclination to the axis of the shaft to cause the clutch to be thrown out 75 in thrust bearing for said helical gear for preventing the shaft from being moved by said gear beyond a neutral position between said clutch members, and yielding means for retaining the clutch plate out of engagement with the other of said pair of clutch members.

6. A driving and stopping mechanism having, in combination, a drive shaft, high and low speed clutch members rotatable on the shaft, a central clutch plate secured to the shaft between the clutch members, manually operable means for shifting the shaft endwise to control the pressure of the clutch plate against the low speed clutch member, power actuated means for disengaging the clutch plate'from the low speed clutch member and actuating it against the highspeed clutch member, and a transmission for the power actuated means, comprising a helical gear on the shaft having teeth cut at an inclination to the axis of the shaft to cause the reaction of the helical gear on the shaft to move the clutch plate away from the low speed clutch member when the pressure is released by the manually actuable means, with a load imposed on-the transmission.

7. A driving and stopping mechanism, having, combination, a shouldered drive shaft, high and low speed clutch member's rotatable on the shaft, a central clutch plate secured to the shaft between the clutch members, manually operable means for shifting the shaft endwise to control the pressure of the clutch plate against the low speed clutch member, power actuated means for disengaging the clutch plate from the low speed clutch member and actuating it against the high speed clutch membena transmission on the shaft having teeth out at an inclination to the axis of the shaft to cause the reactionof the transmission under load to move the helical gear against the shoulder on the drive shaft and the clutch plate away from the low speed clutch. member when the pressure is released by the manually operable means, and a thrust bearing for preventing the reaction of the transmission from moving the clutch plate against the high speed clutch member.

8. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch for driving the shaft, a low speed braking clutch member slidable along the shaft, a low speed driver on the shaft, and means for disengaging the high speed clutch and for engaging the braking clutch member with the low speed driver, comprising a radially cut timing cam connected to the braking clutch member, a follower engaging the cam at one side of the shaft, means for causing the braking clutch member to engage its driver, and thrust means engaging a radial surface on the braking clutch member at the side of the shaft opposite from the cam follower to equalize the pressure between the braking clutch member and its driver at opposite sides of the shaft.

9. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch for driving the shaft, a low speed braking clutch member slidable along the shaft, a low speed driver on the shaft, and means for disengaging the high speed clutch and for engaging the braking clutch member with the low speed driver, comprising a radially cut timing cam connected to the braking clutch member, a follower engaging the cam at one side of the shaft, a yielding slide, means for coupling the follower to the slide to cause the braking clutch member to engage its driver, and thrust means engaging a radial surface on the braking clutch member at the side of the shaft opposite from the cam follower to equalize the pressure between the braking clutch member and its driver at opposite sides of the shaft.

10. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch for driving the shaft, a low speed braking clutch member slidable along the shaft, a low speed driver on the shaft, and means for disengaging the high speed clutch and for engaging the braking clutch member with the low speed driver, comprising a radially cut timing cam connected to the braking clutch member, a follower engaging the cam at one side of the shaft, a slide, means for coupling the follower to the slide to cause the braking clutch to be driven, thrust means engaging a radial surface on the braking clutch member at the side of the shaft opposite from the follower to equalize the pressure between the braking clutch member and its driver at opposite sides of the shaft, and yielding means interposed between the slide and the thrust means.

11. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch 10 for driving the shaft, a low speed braking clutch member s'li'dabl'ealong the shaft, a low speed driver on the shaft, and means for disengaging the high speed clutch and for engaging the braking clutch member with the low speed driver, comprising a radially cut timing cam connected to the braking clutch member, a follower engaging the; cam at one side of the shaft, a yielding slide, means for coupling the follower to the slide to cause the braking clutch member to engage its driver, a thrust lever, means carried, by the thrust l'ever engaging a: radial surface on the braking clutch member at-the side of the shaft opposite from the-follower to equalize the pres+ sure between the braking clutch member and its driver at opposite sides of the shaft, and; a spring interposed between the slide and the thrust lever.

12. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch for driving the shaft, a braking'clutch member slidable along the shaft, a cooperating clutch member on the shaft, and means for dis-engaging the high speed clutch and for engaging the braking clutch member with its cooperating member, comprising a radially cut timing cam connected to the braking clutch member, a lever vibrated by the timing cam, a lock bolt for causing the lever to be restrained against movement by the timing cam when the high speed clutch is disengaged, a lock bolt carrier mounted to move at right angles to the lock bolt, and thrust means connected to the lock bolt carrier for engaging a radial surface on the braking clutch member at the side of the shaft opposite from the fol lower to equalize the pressure between the braking clutch member and its cooperating member at opposite sides of the shaft when the lock bolt engages the vibrating lever.

13. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch for driving the shaft, a braking clutch member slidable along the shaft, a cooperating clutch member on the shaft, and means for disengaging the high speed clutch and for engaging the braking clutch member with its cooperating member, comprising a radially cut timing cam connected to the braking clutch member, a lever vibrated by the timing cam, a lock bolt for causing the lever to be restrained against movement by the timing cam when the high speed clutch is disengaged, a lock bolt carrier mounted to move at right angles to the lock bolt, a. thrust lever yieldingly connected to the lock bolt carrier, and a roll on the thrust lever engaging a radial surface on the braking clutch member at the side of the shaft opposite from the vibrating lever to equalize the pressure between the braking clutch member and its cooperating member at opposite sides of the shaft when the lock bolt engages the vibrating lever.

14. A driving and stopping mechanism having, in combination, a main shaft, a high speed clutch for driving the shaft, a low speed braking clutch member slidable along the shaft, a low speed driver on the shaft, and means for disengaging the high speed clutch and for engaging the braking clutch member with the low speed driver, comprising a radially cut timing cam connected to the braking clutch member, a follower engaging the cam at one side of the shaft, a slide, means for coupling the follower to the slide to cause the braking clutch to be driven, thrust means engaging a radial surface on the braking clutch member at the side of the shaft opposite from the follower to equalize the pressure between the braking clutch member and its driver at-opposite sides of the shaft, and yielding means interposed between the slide and the thrust means proportioned to. cause the force applied to the thrust means to balance the force applied to the follower. 1 I I '1 15. A driving and stopping mechanism having,

in combination, a main shaft, a high speed clutch lever to be restrained against movement bythe timing cam when the high speed clutchis .disengaged, a lockbolt. carrier mounted to move at right angles to the lock bolt, a spring acting on the lock bolt carrier to maintain the carrier yieldingly in position, thrust means connected to the carrier for engaging a radial surface of the braking clutch member at the side of the shaft opposite from the follower and a spring connecting the thrust means and carrier proportioned to apply together with the carrier spring a pressure which is inversely proportional to theratio of the distance between the cam follower and the center of the shaft to the distance between the thrust means and the center of the shaft.

CLYDE L. KNOTT.

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