GB516175A - Improvements in sewing machines - Google Patents

Abstract

516,175. Sewing machines. UNION SPECIAL MACHINE CO. June 22, 1938, No. 18552. Convention date, June 22, 1937. [Class 112] The thread-tensioning and take-up means of a sewing-machine are arranged in an enclosed part of the frame between needle-driving connections at one end of the main shaft and looper and feed connections at the other end. Stitch-forming devices; thread-tensioning devices; threads, controlling otherwise than in stitch-forming.-The invention is described as applied to a two-needle feed-off-the-arm machine having a main shaft 15 supported in four bearings 16 .. 19, with bevel gear connections 12 between the left-hand bearings 16, 17 driving the needle-bar 7 as described in Specification 516,016, and eccentrics 34 between the righthand bearings 18, 19 actuating the looper and spreader mechanism, as described in Specification 516,018, and the feed mechanism as described in Specification 516,017. The threads - controlling devices are arranged in a compartment 71 in the frame, isolated from the driving connections for other parts of the machine by walls carrying the bearings 17, 18. The take-ups comprise two flanged cams 87 on the shaft 15, one handling both the needle threads and the other both the looper threads. Each thread has on individual tension 74, Figs. 2 and 7, comprising a pair of discs 76 mounted on a slotted, threaded pin 78, screwed into the frame, and pressed together by a spring 85 adjusted by a nut on the spindle. The upper disc 76 in the case of the needle-thread tension devices, has a web passing through the slot of the pin 78 for engagement by a pin 111 sliding in a bore in the lower part of the pin 78 and actuated by a cam 110 on a shaft 102 to release the tension when the presser-foot is lifted as described below. A plate clamped between a flange 81 on the pin 78 and the frame carries two pairs of thread-guiding pins 83, and threadguiding passages 89, 93 and 91 are also provided in or -on the frame. Frames.-The compartment 71 containing the thread-handling devices has a cover 95 hinged at one end at 96 and provided with spring friction-fastening fingers 97. The needle-driving gears 12 are enclosed in a compartment provided with a cover-plate 72, an outer cover 67 covering this and the presser-foot lifting mechanism. Presser-bars.-The presser-bar 56, Figs. 2 and 6, sliding in guides 57, 58, is pressed downwards by a leaf spring 61 anchored to the frame at its rear end and formed with a forked front end pressing on the flange of a cap 64 on the upper end of the presser-bar; the pressure of the spring is adjustable by means of a screw 66 passing through the cover 67. The lifting of the presserbar when stitching is not in progress is effected by a crank 98 actuated from a treadle on other control through a crank 103, on the shaft 102 carrying the thread-tension release cams, and a link 105; the crank 98 engages under a collar 100 fixed on the presser-bar. Rotation of the presser-bar is prevented by a lug 68 on the collar 100 engaging guides on the frame.