GB225431A - Clutch device - Google Patents

Abstract

225,431. Fairweather, W., (Singer Manufacfuring Co.). Feb. 27, 1924. Clutches, ratchet; operating clutches.-In buttonhole-sewing and other machines, clutches of the friction roller type are operated by rollerengaging levers moved by a cam rotated by the movement of radially sliding blocks striking successively against a relatively stationary main clutch-operating lever. In buttonhole-sewing machines, a clutch is used to rotate a driven element for part of a revolution to close the work clamp and trip the stop-motion device starting the stitch-forming mechanism, whereupon the clutch is automatically disengaged and the driven element positively stopped. The stitch stop-motion device, when the stitching is finished, again trips the clutch into engagement to rotate the driven element for the remainder of the revolution to cut the buttonhole and the sewing-threads, open the work clamp, &c., whereupon the clutch is automatically disengaged and the driven element positively stopped, as before. The driving-pulley (not shown) has a cylindrical rim between which and cam faces 34 on a plate 28 secured to the driven member 6 are spring- pressed ratchet clutch rollers 32. Bearing on the rollers 32 are levers 30 pivoted on the plate 28 and bearing also on a cam plate 37, which is loose on a central shaft and is slotted to engage a roller 41 on a link 12 connecting a block 9 sliding radially in the member 6 with a second sliding block 10 through the medium of a bell crank lever 17. A spring 20 bearing on the block 10 tends to move both blocks radially outwards. Lugs 23, 26 on the blocks project into the path of a block 48 on a clutch-operating and stop lever 46 turning on a pivot 47, a pin 55 in the lever engaging a cam groove 54 in the hub of the driven member 6. The lever 46, when swung manually on its pivot 43 in starting the action, releases the lug 23 in contact therewith so that the blocks 9, 10 move outward and rotate the cam 37 to remove the levers 30 from the clutch rollers 32 and allow them to clutch together the driving-pulley and the member 6. The cam 54 so returns the lever 46 that the lug 26 strikes the cam surface 51 on the block 48 to disengage the clutch and comes to rest against the stop 52, back motion of the member 6 being prevented by a spring-pressed latch 50. The lug 26 is released when the stitch-forming stop motion actuates the lever 46 again, rotation of the member 6 continuing till the lever 46 is returned by the cam 54 and the lug 23 engages the block 48 at the completion of the revolution.