US2116889A - Sewing machine safety device - Google Patents

Description

May'lO, 1938. H. GUNTHER.

SEWING' MACHINE SAFETY DEVICE Filed July *3,v 1936 2 Sheets-Sheet 1 May 10, 1938. H.. GUNTHER sEwING MACHINE SAFETY DEVICE Filed July 3, 195s 2 Sheets-Sheet 2 y?? @EE fil Patented May 10, 1938 UNITED STATES PATENT oEFlcE 2,116.ss9 SEWING MACHINE SAFETY DEVICE Hermann Gunther, lizabeth, N. J., assignor to- The Singer Manufacturing Company, Elizabeth, N. I., a corporation of New Jersey Application July 3, 1936, Serial No. 88,737

11 Claims.

One of the objects of this invention is to provide an improved safety device which will prevent the Work-clamp from being raised until the predetermined number of stitch-forming cycles has been completed, the usual trimmer mechanism operated to sever the threads, and the machine has come to rest.

Another object of this invention is to provide ay safety device which may be 'readily applied to machines already in use and which is character-.

ized by its compactness, durability and simplicity, and its provisions facilitating its accurate assembly and incorporation in existing machines.

A still further object of this invention is to provide an improved safety device which will prevent the presser-bar lifting lever frombeing raised when the machine begins its cycle of operations or to prevent the machine from being started until theapresser-bar lifting lever is in its normal position. f

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forthand illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention' and the advantages attained thereby will be readily understood by those skilled in the art.

Figure 1 is a rear side elevation of a sewing machine showing my improved safety device applied thereto. l Y

Figure 2 is a sectional view ofthe controlling `cam-and disk, taken along the line 2-2 of Figure l.

locking disk or ring. A

As represented, the machine is constructed with a frame comprising/the cylinder-bed or Work-arm I from which rises the standard 2 carrying a bracket-arm ril terminating in a hollow within the free end of the hollow .cylinder-bed I. y

The work is adapted to be clamped between the *upper and lower members of a work-holder Figure 3 isa perspective view of the clampmain-shaft 5.

which, in the particular embodiment illustrated, is moved to and fro over the work-support to position the stitches in accordance with the'desired pattern. The present work-holderis of the general type disclosed in the patent to Barron No. 1,205,317, of November 21, 1916', and comprises the sliding bar 8 carrying a work-supporting plate 9 at the end adjacent the stitch-forming mechanism. Mounted on the bar 8 is a bracket Il having at itsfree end a head II which carries the usual presser-bar I2 terminating in a workclamp or worl-holder I2' which is spring urged towards the plate 9. Projecting forwardly from the presser-bar I2 through a slot in the face of the head II is a rod I3 the extremity of which lies above and in the path of vertical movement of the arm I4 of a bracket-piece xed to the lower end of the usual work-holder lifting bar I5 carried by the head 4.

The work-holder is moved longitudinally of the Work-arm I by means of the usual cam slot 5|! in the inner face of the controller cam wheel I6 (see Fig. 2), which imparts rocking motion to a lever II. The motion of the lever Il is communicated in a well known manner to the vertical postv I8.n rising from the rear end of the bar. The workholde'r is vibrated laterally of the work-arm I about the post Il as a pivot by means of the usual connections with the cam slot I9 in the outer face of the controller cam I6. The connections include the bell-crank lever 20, pitman 2|", rockshaft 22 and arm 23. 'I'he means for imparting longitudinal and lateral movements to the workthread-cutter, not shown, for cutting the threads usual belt shifting guide arm 4I rigid with it.

The stop-lever 4I) carries A the Spring pressed plunger rod 42 adapted to engage the Stopping cam 43 iixed to the pulley 44 which is xed to the The cycle of operation of the machine is Started by actuation of the angle lever 45 which causes the lever 40 to move to the right as Y idler pulley 46 to the fast pulley 44 thereby starting the cycle of-operation. The stop-lever 40 is locked in running position (the position shownin latch 48 mounted upon the frame 49 by means of the fulcrum screw stud 5l and is adapted to be tripped for disengagement of the stop-lever by means of the tripping stud 52 carried upon the inner face of the controller cam i6. The threadcutting and stop-motion mechanism are fully described in the said Horton patent and further description is deemed unnecessary.

It will be understood that a machine. of the present type when tripped into action, automatically performs a definite series of operations under control of the cam l and is then brought to rest by the stop-motion device. Operators of these machines often anticipate the moment that the cycle of operation is completeand press on a treadle' which, in practice, is connected by a chain to the usual presser-bar lifting lever which is pivoted to the arm 3 at 25. The 'operator sometimes presses on the treadle and raises the presser-bar and work-holder before the machine has come to rest and when this occurs the thread or needle may be broken, o r the thread-cutter may not have had time to operate and sever the thread close to the underside of the work. To make it impossible for the operator to raise the presser-bar by pressing on the treadle before the machine has come to rest I have provided the machine with an attachment which may be readily xed to existing machines. The attachment comprises a ring 2l detachably secured to the outer face of the controller cam it by the screws 28 and a hardened steel ringer 3l which is adjustably secured to a substitute presser-bar lifting lever 2&3 by the set screw 32, the lever 2d having a treadle-chain lug 24. The controller cam is rotated 180 for each operative cycle of the machine and the ring 21 is formed with two diametrically opposite notches 29 and 30 in its l periphery with which the finger 3l alternately registers when the machine is in stop position.

' It Ywill be obvious from the foregoing that the nger 3l normally rides upon the periphery of the ring 2l and the ring 21 is so timed with the operation of the machine that the finger overlies one of the notches 29 or 30 only when the machine is in stop position and. therefore, the lever 24 can only be operated to lift the presserbar when the machine has come to rest.

The ring 2l is made of cast iron and to prevent excessive wear on the edges of the notches 29 and 3B and also to provide means for accurately timing the point in the cycle of operation of the machine at which the lever 24 may be operated, hardened steelwear plates 33 are adjustably secured in grooves 3G in the periphery actuated during the initial stitch-forming cycles and before theiinger 3l rides out of the notch the free end of the lever 24 may be extended to a. point at which it will overlie the belt-shifting guide arm 4I when this arm is in the position indicated in dotted line in Fig. 1. As previously described the angle lever 45 is actuated to move the stop-lever 40 and belt-shifting arm 4l to -the right as viewed in Fig. 1, and it will be obvious that if the lever 24 is depressed so as to raise the presser-bar I2 the free end 41 of the lever will prevent the beit-shifting arm 4| and stoplever 40 from being shifted to the dotted line position to start the machine. On the other hand, if the lever 24 is in the position shown in Figure 1 then the stop-lever 40 and belt-shifting arm 4i may be moved to the dotted line position to start the machine and it will be noted that when the arm 4I is in the position shown 1n dotted lines the lever 24 is locked so that it cannot be actuated to raise the work-clamp. Just prior to the end ofthe cycle of operation the stop-lever 40 and arm 4I are automatically shifted back to the full line position and therefore, the arm di is moved out of the way of the end 4l of the arm 24. However, the finger 3l is riding on the disk 21 at this point inthe cycle and consequently the lever 24 cannot beactuated until the nger 3l overlies one of the notches 29 or 30 in the ring 2l, at which time the machine has come to rest.

It will be apparent that the above described construction may be modified so that operation of the lever 24 is prevented by other movable p of work-clamp it will be obvious that other types" of work-clamps may be used and my improved safety device may be embodied in various types of sewing machines that perform a definite series of operations and then come to rest.

Having thus set forth the nature of the invention, what I claim herein is:-

1. In a sewing machine adapted toperform a definite series of operations in combination stitchforming mechanism including a reciprocatory needle, a shiftable work-holder, a cam for con trolling the shifting movements of said workholder, manual means for raising and lowering said .work-holder and means carried by said cam for preventing said work-holder from being raised until the machine has completed its series of operations.

2. In asewing machine adapted to perform a denite series of operations, in combination, stitch-forming mechanism including a reciprocatory needle, a work-holder, means for causing said needle and work-holder to vibrate relative to each other, a cam for controlling the series of operations of the machine, means for raising said work-holder, and means under control of said cam for preventing the work-holder from being raised until the machine has completed its series of operations.

3. An attachment for a sewing machine having a work-holder, means for raising said workholder, and a rotatable cam, comprising a ring attachable to said cam 'and mechanism interposed between said ring and said raising means for preventing said raising means being operated except at predetermined intervals.

4. An attachment for sewing machines having a rotatable element, a work-holder and means for. raising said work-holder, comprising a memtory needle, a. stop-motion device, a cam for con-.- n trolling the cycleof-operation of the machine:l l a work-holder, a lever for raising and lowering said'work-holder, a member on said cam and means under the combined control of said stopmotion device and said member for preventing thelever from being actuated except at predetermined times to raise the work-holder.

6. In a sewing machine adapted to perform a definite series of operations, in combination, stitch-forming mechanism including a reciprocatory needle, a stop-motion device, a cam for controlling said stop-motion device, a work-holder, means for raising said work-holder, means under control of said stop-motion device for preventing said work-holder vfrom being raised at the beginning of the cycle of operation and a member carried by said cam for preventing said workholder from being raised until the machine has completed its cycle of operation and come to rest.

7. An attachment for a sewing machine having a work-holder, a lever for raising said workholder, and a controller cam, comprising a finger carried by said lever and a ring adapted lto be secured to said cam, said ring having a plurality of notches in its periphery which are adapted to underlie the finger on said lever at predetermined times, whereby said lever may be actuated to raise said work-holder.A

8. A safety device for sewing machines having a work-holder, a lever for raising said workholder and a cam for controlling the operation of the machine, comprising a ring actuated by said cam and having one or more notches in its.

outer periphery. and a linger adiustably secured -a lever for raising said work-holder, means shiftable into the path of movement of said lever at the beginning of a series of operations to prevent said work-holder from being raised, and a second means for preventing said lever from being raised until the machine has come to rest.

10. In a sewing machine adapted to perform a definite series of operations in' combination,

stitch-forming mechanism including a reciproca# tory needle, a work-clamp, a stop-motion devicel including a pivoted lever, and a clamp lifting lever having interengaging relation witi said lever. 11. In a sewing machine adapted to perform a definite series of operations, in combination, stitch-forming mechanism including a reciprocatory needle, a work-clamp, a stop-motion device including, a pivoted member, and a clamp-lifting lever, said member and said lever being so constructed and arranged that each is movable into the path of movement of the other.

HERMANN GNTHER.

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