US2358731A - Thread-end clamping device - Google Patents

Description

Sept. 19,1944. c, U, OLSON 2,358,731

THREAD-END CLAMPING DEVICE Filed June 5, 1942 IN VEN TOR.

Cfzarls Z Olson: I

Patented Sept. 19, 1944 UNITED STATES PA I NT FEE Q THREAD-END GLAMPING DEVICE Charles U. Olson, Evanston, Ill. f g f Application June 5, 1942, Serial No; 4455878 2 claims; (01.1'12-252) 1 The present invention relates to a thread-end- 'clamping device adapted for use in connection with a sewing machine whereby unintentional withdrawal of the thread end from the eye of the needle due to accidental movement of the thread in a direction away from the needle may be effectively controlled without impairingthe free feeding of the thread to the needle as required by the sewing operation;

It is a further object of this invention to pro-' claimed and illustrated in the accompanying drawing:

Fig. 1 is a fragmentary elevation showing the present thread end clamping attachment in cp erative position on the frame of a conventional sewing machine; in the full lines the presser foot and presser foot lever are shown with the parts positioned as when in thread-clamping position and in dotted lines with the parts positioned as when in thread-releasing position.

Fig. 2 is an enlarged detail View of the present attachment showing the position of the parts when the same are in thread gripping position.

Fig. 3 is a similar view showing the position of parts when the thread is in released relation and being fed to the needle during sewing.

Fig. 4 is a sectional View on line 44 of Fig. 1.

Fig. 5 is a detail view taken on line 5-5 of Fig. 4.

The thread-end clamping mechanism contemplated by this invention is preferably mounted on the sewing machine head portion or frame in which the needle mechanism and the presser foot shaft operates. 7

Reference being had more particularly to the drawing, |0 designates a supporting member or plate having an opening near an edge thereof through which the member l0 may be attached to the side of the sewing machine head by the usual screw fastening at the lower limits of a plate usually employed to enclose the needle and presser foot mechanism in the machine head. The upper portion of the plate I0 is preferably offset outwardly of its lower portion so as to permit disposal of the upper portion of the plate III on the machine head plate I above the shoulder at the lowerlimits of said platen and yet dispose" the lower part 01" theplate ID in a verlGYCtILl'plarie in proximityto the path of movement of the needle l8. 7

Secured to the plate H] are a pair of eyes I5 and I6 through which the thread n is arrange to travel lengthwise of the plate Ill in a path oblique to the path of the needle l8. Intermediate the eyes I5 and 16 "is a cylindrical member 23 mounted for rotation about a'pivot 24 about which the thread I1 is adapted to be drawn bent in its path between said eyes l5 and l6. The thread I1 is preferably ar'range'd to contact the surface of the member 23 through an arc of sub-;

stantially degrees by means of a bearing or cylindrical member 20 projecting from the plate Ill just below the limits of theuppe r portion of the plate 'H] and a similar bearing 20 projecting from the plate I0 just below the cylindrical member 23. The member 23 is so arranged with respect to the pivot 24 that its center of gravity is below the pivot 24 whereby the member 23 is adapted to rotate by gravity toward a position in contact with the portion of the thread ll in engagement with the bearing 2| therebelow. Ac-

oordingly, movement of the thread IT in a direction away from the needle l8 will cause the thread H to exert suflicient frictional contact with the member 23 as to tend to drive the member 23 into closer clamping engagement with the thread I! engaging the bearing 2|, to positively limit further movement of the thread in a direction away from the needle l8.

Operation of the member 23 in a direction away from the thread I! engaging the bearing 2| to permit release of the thread I! for movement toward the needle I8 is brought about upon initial movement of the thread IT in a corresponding direction due to the frictional contact provided between the thread I1 and the member 23 which tends to drive the latter in a movement away from the bearing 2|.

Due to vibration set up in the frame of the sewing machine during sewing whereby unintentional movement of the member 23 into clamping engagement with the thread sometimes occurs, it is desirable to provide means for positively maintaining the member 23 in a position clear of the bearing 2| during sewing operations. To this end the plate I0 is provided with a slot 32 in which a pin 3| projecting from the bearing or member 23 isadapted to establish limits for rocking movementof the member 23. The pin 3| is so extended as to intersect the path of a lever 30 mounted for pivotal movement on the reverse side of the plate I!) whereby the lever 30 may be operated to raise and hold the pin 3| in a limited position with respect to the slot aforesaid and thereby maintain the member 23 away from the bearing 2|. Operation of the lever 30 is obtained through a leaf spring 35 anchored to the lever 30 and preferably projecting laterally into the path of a suitable lug or projection carried by the presser foot bar of the sewing machine. As shown in the drawing, the lug may take the form of a conventional cutter blade 36 mounted for adjustment on the presser foot bar.

Thus when the presser foot is in idle or raised position the blade 36 is lifted to a position clear of the leaf spring 35 so as to permit the member 23 to operate by gravity to assume a thread clamping position, and when the blade 36 is lowered through lowering ofthe presser foot shaft and presser foot into operative or sewing position, the blade 36 engages the spring 35 to resiliently hold the pin 3| against the edge of the slot to limit or bias the member 23 into a position clear from the bearing 2| so as to release the thread l'l for movement toward the needle l8.

from its spirit and scope as set forth in the ap-;.

pended claims.

What is claimed is:

1. In a thread-end clamping .device adapted for attachment to the frame of a sewing machine,

25 The arcuate thread engaging surfaces of the a supporting member, means associated with said supporting member through which a strand of thread is trained to travel in a predetermined path including a bearing presenting a threadengaging surface of convex cross-sectional contour; means cooperating with the thread portion in engagement with said bearing to prevent movement of the thread in a direction away from a needle associated with said machine including a member pivotally mounted on said support for movement on said support toward and away from said bearing and about which said thread strand has contact throughout an arc of substan tially 180 degrees, and means through which said member is biased to a position away from said bearing including a resilient lever adapted to coact with a projection on the presser foot shaft of said machine when the presser foot is in work position, V

'2. In a thread-end clamping device adapted for attachment to the frame of a sewing machine, a supporting member, means associated with said supporting member through which a strand of thread is trained to travel in a predetermined path including a bearing presenting a thread engaging surface of convex cross-sectional contour, means cooperating with the thread portion in engagement with said bearing to prevent movement in a direction away from a needle associated with said machine including a cylindrical member mounted for pivotal movement on said support toward and away from said bearing and biased by gravity for movement toward said bearing, and means actuated by the presser foot control associated with said machine for eifecting movement of said cylindrical member away from said bearing.

CHARLES U. OLSON.

Images