Patent GB-191205453-A (GB)
Title: Improvements in or relating to Starting and Stopping Mechanism for Sewing or other Machines.
Inventor: BOULT ALFRED JULIUS
IPC: D05B69/22
Filed: 1911-09-04
Granted: 1912-09-04
Abstract: 5453. Boult, A. J., [United Shoe Machinery Co.]. Sept. 4, 1911. Sewing-machines; stopping-gear, non-automatic.-A stopping - mechanism for high-speed sewing and other machines comprises the combination with the main driving-mechanism adapted to be thrown into and out of operation by the operator, of a low - speed driving- mechanism which, when thrown into operation acts first as a friction brake to retard the movement of the machine and then drives the machine at a reduced speed to stopping position, and means timed by the driven parts of the machine for throwing the low-speed driving-mechanism into operation when the main driving-mechanism is thrown out. The low-speed driving- mechanism may rotate in the same direction as or in the opposite direction to the high-speed mechanism. The application to shoe-sewing machines of the type illustrated in Specification 17,328/08 is described. The cam shaft 6 is driven during the sewing operation by a pulley 7 and is controlled by a treadle-operated clutch. A clutch member 18 is mounted to run loose on the shaft 6 and is driven continuously at slow speed in the reverse direction by worm gearing 19 and belt 22. The member 18 is connected to the shaft 6 to slow it down and then reverse it when the main drive is stopped by mechanism constructed as follows. An inner clutch member 18<1> is mounted on a sleeve 29 secured to the pulley 7 by a slide-block 27 and a spring-pulled bolt 28. A cam-groove 31 in the sleeve engages the end of a bell - crank lever 32 and rocks it idly during the sewing operation. When the main drive is stopped, the free end 33 of the lever is locked, thereby causing the sleeve 29 to slide on the shaft 6 against the pull of the spring 28, and so putting the clutch 18, 18<1> into operation. The clutch acts first as a friction brake to stop the forward rotation, and then the member 18 drives the shaft 6 backwards until the ' stop ' position is reached, when the cam 31 acts to separate the clutch members 18, 18<1>. The locking-bolt 34, Fig. 5, for the lever 32 is mounted in a slide 35, the movement of which is restrained by an adjustable spring 36, which thus determines the friction between the clutch members. The locking-bolt is pressed upwards by a spring 40, but is held down out of engagement with the lever 32 by a connexion 47 with the starting-treadle. the base 45 of the bolt 34 carries a rock-shaft 43 having an arm 46 connected with the rod 47, and a latch 41 which is rocked 'by the shaft 43 through a pin - and - slot lost-motion device. When the treadle is depressed, the rod 47 rocks the shaft until the latch 41 bears against the slide, and then the bolt 34 is drawn down until the latch passes under the shoulder 42. When the treadle is released, the bolt does not move upwards to engage the lever 32 until the rock-shaft 43 has dislodged the latch 41. A positive stop 48, Fig. 6, and a brake band 48' may be provided for the cam shaft 6. The stop 48 engages a shoulder 50 on a disk on the cam shaft, and is operated by a lever 52 pivoted at 49. This lever is rocked by the device 153, which in machines of the type described in Specification 17,328/08 is actuated by the reversal of the cam shaft to throw off the thread tension. The brake band 48' may also be put on by the lever 52. The brake-band may be released on starting by a connexion with the treadle-operated rod 47. A pin on the rod enters a slot in a lever 123 which is adjusted to turn the eccentric stud 125 to which the brake-band is attached.