GB347056A - Cam and follower mechanisms - Google Patents

Abstract

347,056. Cam mechanism. FAIRWEATHER, W., 65, Chancery Lane, London. - (Singer Manufacturing Co.; Elizabeth, New Jersey, U.S.A.) June 21, 1930, No. 18968. [Class 80 (iii).] In a cam-and-follower mechanism particularly for use in sewing-machines, means are provided for projecting the follower into the cam groove, together with a latch for detaining the follower outside the groove, and normally idle means on the cam to trip the latch when the groove is in register with the follower, and manual means for rendering these means active. The invention is illustrated as applied to the clamp-closing mechanism of a buttonhole sewing-machine. The work-clamp 9 of usual form, has an arm 10 fulcrumed at 11 on a block 12 carried by a plate 8. The arm is depressed to closed position by a cam 13 on a rock shaft 14 having a rearwardly extending arm 15 in position to be depressed by the roll 16 on the arm 17 of the usual three-armed lever 17, 18, 19 fulcrumed at 20 on the standard 2. The arm 18 carries a slide bolt 21 constituting a cam follower provided with a roll 22 entering the groove 23 in the cam wheel 25. This wheel has a belt groove connected to the source of power. The plunger 21 is prevented from entering the groove by a latch arm 33 rocking on a stud 34 and urged by a spring 35. A manually operated bell crank 37, 38 is also mounted on the stud 34 connected by a rod 39 to a treadle or finger lever. When the rod is pulled down to start the machine a latch 40 holds it in this position throughout the cycle of operations. An arm 38 of the bell crank carries a latch 50, rock shaft 47 and crank arm 48. A shoulder 54 of the latch lever engages a pin 55 on the latch 33 and releases this when the follower is in register with the groove.