US1191635A - Stop mechanism for sewing-machines. - Google Patents

Description

J. WHITELAW.

sToP MEcHAmsM FQ'R SEWING MACHINES.

` APPLICATION FILED AUG-27. 19|4.

IPatented' July 18,1916;

3 SHEETS-SHEET 1.

`1. wHlTELAw. STOP MECHANISM FOR SEWI'NG MACHINES.

APPucATloN FILED Aue'.27. 1914.

l Patented July 18, 1916.

' SSHEETS-SHEETZ.

I. WIIITELAW.

STOP MECHANISM FOR SEWING MACHINES. APPLICATION FILED AUG.27. I9I4.

- 3 SHEETSv-SHEETQ- da 6'.

17a/7565 www MQIW UNITED STATES PATENT oEEroE.l

JAMES WHITELAW, orv

ST. LOUIS, MISSOURI.

STOP MECHANISM FOR SEWING-MACHINES.

Application ined August 27,

T o all whom z't may concern.:

Be' it known that I, JAMESYWHITELAW, a citizen of the United States, residing at St. Louis, in the State of Missouri, have invented certain new and useful Improvements 1n Stop Mechanism for Sewing-Machines, of

' which the following is a specification.

` operation without injurious jar or shock to the arrested mechanism. A.

A further object of my invention 1s to provide a construction of the character de scribed employing jointly and cooperatively a yielding, self-returning stop-member and a brake actuated thereby, both acting on the parts to be' arrested, so that the progression l of the moving parts past the cyclic point in their movement where the stopping devices` are thrown into action is short, and the arrested, parts are spring-returned to their position of rest. f

Another object of my invention is to simplify and improve the construction of Stop motion devices for sewing machines and the like by novel correlation of clutching, stopping, stop-timing and operating mechanisms; and to improve in construction the elements and sub-combinations thereof.

In the drawings wherein -I have illustrated a single embodiment of my invention as applied to a sewing machine, for purposes o f full disclosure` Figure 1 is an illustration, diagrammatic in parts, of a sewlng machine, equipped with stop-motion andpower transmission means embodying my invention; Fig. 2 is an extended perspective of the stop-motion and clutch parts; Fig. '3 is aY vertical, longitudinal section therep through; Fig. 4 is a perspective detail of a clutch part; Fig. 5 is a perspective detail of a connector part.; Figs.v 6, 7 and 8 are sections on lines 6--6, 7-7 and 8 8 of Fig. 3;

Fig. 9 is a section on line9-9 of Fig. 1.

In the drawings 10 indicates. the main shaft of a sewing machine and b the fixed bearing at its power receiving end, beyond which the shaft projects .toreceve thestop Specication of Letters Patent.

1914. Serial No. 858,807.

motion and clutch devices. In the particular construction shown, a block 11-is keyed at l2 to the shaft to rotate therewith. It carries, relatively, theaxially shiftable means that throws into action the powerwheel clutch and the shaft-arresting means. The axially shiftable connector shown is a stifl'l baror key, 13, slidable axially in a groove 14 provided therefor lin block 11 and Patented July 18,1916'.

shiftable by the bell crank shifter-lever 15.

through .the intermediary of the conventional shifter yoke 16 and, grooved shifter vmember br controller 17, the latter secured as by screw 18'to theA shiftable bar 13. When moved to the right,v (Figs.v2 and 3,)

the shiftable member or connector, 13, sets a i clutch that connects power wheel 20 with the shaft 10; and when moved to the left said connector member throws the shaftstopplng appliances into action.

Power wheel 20 is loosely mountedy on the shaft 10-between the fast end collar 20a and the fast block 11, said wheel having in its inwardly facing hub .20 an annular recess 21 receiving-the reduced annular extension 11 of the block l1. In the annular clearance between the parallel surfaces 'of extension 11 and the outer wall of hub 20 is an expansible clutch-band 22 that rides in rotation with the fast block 11. In the particular construction shown the split clutch band 22, under normal tension, frees the power wheel 20, but it is expansible by the connector 13 to make fast frictional engagement.

with the power wheel and so, through the clutch, the connector member and the block 11, to communicate motion tothe shaft 10.

Specifically the confronting end-'walls 22 of the split clutch-ring converge outwardly and in the wider portion of this tapered Islit-*space there normally lies the outer end of' the connector member 13, so that the clutch-band is positively carried in rotation with the' shaft 10 at all times. The' walls of the connector member confronting the converging walls 22"of the clutch member are. .y

recessed and provided with spring-positioned anti-'frictional rollers 23, so that whenv` the clutch member isl moved to the right said rollers, riding along the converging faces 22 expand the clutch-band. This condition is shown in Fig. 3.

It will be observed that by the specific construction shown I am able to provide a veryefectively-working friction clutch, operable on relatively short movementv of the `(.:on-

1T receives a movable brake member, pref-` erably in the form of a split band 25 having one end rigidly mounted, through standard 2G and bolt'iZT, on a suitable part of the machine frame, and at its free end, arranged for compression-applying movement to be controlled by connector 13. Specifically the free end of the brake band carries a spring housing b() recessed to receive a compression spring 31 through which the brake-setting pressure is applied. Through the hous-` ing and spring passes a rod 32 having at its upper end a head 33 and at its lower end,

where it passes through the bottom of the housing, receiving the adjusting nut 31. Obviously, down 'ard pressure on head 33 will compress the spring and through the spring tension'will tend to set the brake, and when the connector-member 13 is appropriately moved to. the left it serves to communicate power from the main shaft to the spring-head 33 to cause the depression of the spring-head.

As an intermciliary between the controller member and the brake setting spring I preferably provide a striker member 40, and preferably associate with said striker a timing member or guard structure 41 that insures proper co-action of the connector 13 and the striker. When permitted by the guard 41, connector member 13 may positively engage the striker 40, to carry it in rotation and cause it functionally to act upon the brake-setting spring.

1n the specific construction shown,striker member 1() is a plate loose on the shaft 1'0 and interposed between the inner end of block 11 and the bearing block Y) or other appropriate part of the machine frame. The striker is capable of oscillatory movement to an extent limited by engagement of a pin 42 on the machine frame in a slot 43 of the striker, and it has a laterally bent finger 44 overhanging the head 33 of the brake-applying` spring, by which said striker is normally held in raised position as shown in Figs. 7 and 8. The b'ake construction is so located that the spring stands substantially tangential to the path of movenient of the striker-tinger 44. At a` suitable point in its periphery the striker is provided with a notch l5 of suitable depth to receive a head 13 of the connector-member 13. and in rear of the notch the perimeterbf the plate is cut down smaller than the maximum radius of head 13', as shown at i6. The annular surface of said striker plate in the axial path of said head 13. is preferably tapered or gradually thinned in a spiral 11T leading downward into the notch 15. If the head 13 of the controller 13 be pressed to the left, to make contact with the annular surface of the striker -LO a suitable time, or considerably number of degrees, before the controller reaches notch 45, said controller head will glide down the tapered surface 17 and make positive, square engagement with the leading end l5 of the notch -t so as to carry the striker rotatively with the shaft to compress the spring 32 and set the brake. It is important, however, in a machine wherein the rotating parts move rapidly, as in a high speed sewing-machine, that provision be made to insure that the connector 13 shall either make good, substantial contact with the notch wall 45 or shall not engage the notch at all; this to prevent battering up of the acting surfaces of the two parts, and other injury to the machine, by partial or ineffective engagement thereof. To this end the guard or timer Ll1 is provided. In the speciflc construction shown said guard takes the form of a met-al shield-piece pivoted between its ends, as at 50, to the extended finger of the striker, and acted on by a spring 51, interposed between its rear end and the striker, so that its forward or leading end, (which is preferably slightly thicker than the thickness of the striker member 10,) may normally rest uponthe suitably-reduced perimeter 46 of the striker plate 40 partially to close the notch 45. The receiving end of the guard is curved outwardly so that its end is located radially beyond the rota- .tive path of head 13 of the Connector, and

is provided with a tooth 53 with its receiving surface inclined` and its front edge squared, spaced apart from the wall 15 of the striker by the width of connector-head 13. Consequently. if the key or connector 13 be moved to the left to function with the striker at a time, in the rotation of the main shaft, before its head 13 axially registers with the guard member 41, the connectorhead, following down the inclined surface l? of the striker, will pass freely under the receiving end of the guard, and.` cooperating with the inclined portion 52 of the guard, will tilt the guard outwardly so that obviously the, connector head may; proceed un- `interruptedly under the tooth "53 and into engagement with the notch 45 of the striker. In such positoin it is fixed in relation to the striker, by wall 45 on the one side, tooth 53 on the other. But if the connector head vhas passed rotatively beyond the receiving end 52 of the guard 41 before the effort is made to engage the connector with the striker plate. then, as indicated iu dotted lines in Fig. S, the side surface of the guard -out making effective engagement with the,

striker. Ofcourse when the operator is thus trying to stop themachine t-he neXt revolution of the main shaft will bring about the desired result.

My stop motion construction may, of`

course, be applied to many forms of sewingmachines and many machines for other purposes, and its shifter yoke, or equivalent part, may be operated y in` any suitable fashion. In Fig. 1,however', I have shown diagrammatically parts of a machine for blind stitching of the general type known as the' Lewis machine, and in said illustration p represents diagrammatically a rigid presser foot, w a movable work handling mechanism below the presser foot, susceptible of being depressed against the tension of spring s to permit insertionY of thework. In such installations I prefer that the connections for ooerating thestop motion controller be combined with the connectionsfor operating the work handling mechanism, and in the specific construction shown the bell crank shifter lever 15 has link connections 60 with arocking gate 61 pivotally carried by a longitudinal' shaft 62 of the machine, said gate having a lever arm 63 extending therefrom in the path of movement of a rocker. 64 that also works on spring s to control depression of the work handlingmechanism w, said rocker being provided with a connection 67 extending to. any suitable lift or foot treadle. A spring 69 interposed between the bell-crank shifter-lever 15 and the part of :fi-ector member 18, rotatable with, but slid-4` able axially on, the main shafts, is thrown to the right, its antifrictional rollers 12 'spread i the band clutch 22 making effective clutchA engagement with the power wheel 20 so that power is applied to the main shaft 10. lVhen the slidable connector' or key 13 is moved. to the left during such part of the cycle of rotation of the main shaft that the head 13 of the connector may not strike upon the side surface of the timer guard 41, the left end of the connector will follow the incline 47 of the striker plate, 40` moving the guard 41 on'V its pivot, and the connector end will make positive 'engagement in the notch 45. Then the shaft is thus freed from the clutch and positively connected with tlic'strikeifLO, it

carries the latter around through a few degrees of rotation, the finger 44 `of the striker acting on spring head 38 to compress the spring 32 that vis carried by the brake band. This action I have found` in practice to be highly effective. By the combined action of the 'yielding spring and the friction brake the shaft is stopped substantially without jar or shock injurious to the machine. hOf course the higher the speed of the machine the further the spring will be compressed and the quicker will the'spring band V,be applied; but when the spring has acted and .has received. its compresslon, 1t returns the striker to its normal position, turning the shaft backward a fewdegrees. The return movement of thestrikeris limited by slot 43, and it will be noted, tooth 53 prevents overthrowing of the shaft due to the back-kick of spring 32 so *that the shaft-stoppage is uniform, and its final position `of rest is the same whatever may have been its running velocity. In a sewing machine, of course, this position at which the shaft is stopped is such that the needle isout ofthe goods, so that when the work handling devices are properly' positioned the goods may be free formanual movement.

claim is 1. In a stop motion for stopping a shaft at y Having described my invention, AwhatI apredetermined rotating position, the com- 2. In a stop motion, the combination of a rotatable shaft, aloose striker, a spring for opposing rotation of said striker, means carriedk inrotation by the shaft, axially shift-ll able thereon to engage or disengage said striker, and means to prevent engagement of said shiftable means andthe striker during a predetermined portion of the cycle of rotation of the shaft.

'3. In a stop motion of the character described, the combination vof. a shaft, brake means therefor including a band brake, and a brakesetting compression spring, a Striker loose on the shaft arranged-for cooperation with said springto compress said. spring and set said brake4 when said striker' is turned with the shaft, and means on the shaft, carried in rotation therewith, to move'k the striker, the last said means and the striker relatively movable to engage or disengage them.v

y 4. In a stop motion of the scribed, the coml'iination of a shaft, irake character de- "part for` coaction with. the Ispring movmeans, therefor including a band brake, and we a brake setting compression spring, a striker loose on the shaft arranged for cooperation with said spring to compress said spring and set said brakeV when said striker is turned with the shaft, means on the shaft, carried in rotation therewith, to move the striker, the last said means and the striker relatively movable to engage or disengage them, and a guard member for preventing engagement of said means with the striker during a predetermined portion of the rotating cycle of the main shaft.

5. In a device of the character described, the combination of a shaft, a` loose power wheel thereon having an inwardly facing recess, a split circumferentially expansible clutch-band within said recess rotatable with the shaft, shaft stopping means normally disconnected from the shaft, an axially shiftable member carried in rotation by the shaft, movable in one direction to expand said clutch-band and in the other direction to actuate said stopping means.

G. In a stop motion, a shaft, a loose part, means rotatively fast on the shaft axially shiftable thereon to engage said loose part; a. compression spring arranged tangentially to said loose part to be compressed thereby, and a band brake for the shaft comprising a split ring carrying a spring receiving socket at one end.

7. In a stop motion, a shaft, band-brake means therefor comprising a split compression band fast at one end and loose at the other, andV having a spring-socket at its loose end, a coiled compression spring carried by said socket, and means rotatable with said shaft forcompressing said spring.

8. Ina stop motion, a shaft, a band-brake means therefor comprising a split compression band' fast at one end and loose at the other, and having a spring socket at its loose end, a coiled compression spring carried by said socket, and means for compressing said spring comprising a. loose striker and a connector rotatable with the shaft and axially movable to engage or disengage the striker.

9. In a stop-motion, the combination of a shaft, a block fast thereon, a connector slidable in said block, a controller member fast on said connector, a shifter lever for said controller, a band brake coacting with said controller member, a compression spring connected with the brake to set it when the spring is tensioned, and a striker loose on the shaft, arranged to be engaged by the connector and, when so engaged, compress the spring.

10. In a stop motion for stopping a shaft at a predetermined rotating position, the combination with brake means for the shaft, of a. spring cooperating with said brake to set the brake when the spring is tensioned, a part for coaction with the spring movable rotatively with the shaft to tension the spring, means for effecting cooperation of said part and spring, and means to prevent such cooperation during a predetermined interval in the cycle of shaft rotation commencing approximately a quarter revolution in advance of the point of coperation.

l1. In a stop motion of the character described, the combination of a shaft, brake means therefor including a band brake, and a brake setting compression spring, a striker loose on the shaft arranged for cooperation with said spring to compress said spring and set said brake when said striker is turned with the shaft, means rotatable with the shaft and axially movable to engage or disengage the striker, and a guard member pivoted to the striker' and lying in the rotary path of the last said means for preventing engagement of said means with the striker during a predetermined portion of the rotating cycle of the main shaft.

In testimony whereof I hereunto set my hand in the presence of two subscribing witnesses.

JAMES VVHITELAW.

In the presence of R. M. LAWRENCE, J onN D. Rirrnr.

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