GB1003052A - Tool control mechanisms - Google Patents

Abstract

1,003,052. Controlling change speed gear, clutches and brakes. HANSEN GLOVE CORPORATION. Nov. 13, 1961, No. 40535/61. Headings F2C, F2D and F2L. A drive for a sewing machine needle-drive shaft 51 comprises an electric motor 16, a high speed electromagnetic friction clutch 22, 28, a low speed electromagnetic friction clutch 40, 28 for reduced drive through a gear train 30, 31, 39, 40, and an electromagnetic friction brake 49, 36 acting on the shaft 51 through the gears 39, 40 and the engaged low speed clutch 40, 28, and the control comprises a two-way treadle switch 63 energizing the clutches 22, 28 or 40, 28, and a two-way treadle switch 64 which, to stop the shaft 51 in either of two predetermined stopping positions (needle " up " or " down "), selectively energizes the brake 49, 36 through rotary switch means associated with the shaft 51. The drive is so arranged that before the shaft 51 is stopped it is first brought down to its low speed to reduce impact and permit stopping in a more definite position. The high speed clutch comprises a flywheel 22 adjustably secured to a hub 23 on the shaft of the motor 16, a friction disc 28 splined on a shaft 26 driving the shaft 51 through a belt 53, and a slip-ring energizing coil 25 rotating with the flywheel 22. The low speed clutch comprises the disc 28, the gear 40 and a stationary coil 45. The brake comprises a stationary brake member and coil 49, 34, and a clutch/ brake friction disc 36 splined on the shaft 33 integral with the gear 39 and engageable with the gear 31, by a spring 35, to complete the reduced drive train or the brake member 49, by energization of the coil 34, to station the shaft 33. The rotary switch means comprises an insulated commutator ring 77 which is in continuous contact with a brush 76 connected to the coil 34 and which has an offset pad 78 co-operating with diametrically opposite needle " up " and " down " brushes 60<SP>1</SP>, 61<SP>1</SP> connected to the switch 64. In operation, for high speed drive the treadle switch 63 is depressed to the position shown (in full line) for energization of the coil 25. To stop the needle in a selected position the treadle switch 63 is released to its opposite position to de-energize the coil 25 and energize the coil 45 for low speed drive, and the treadle switch 64 is moved to a selected position, e.g. as shown, in which, when the brush 60<SP>1</SP> is engaged by the pad 78, the coil 34 is energized to stop the needle in its selected position. For continuous low speed drive a switch 65 is opened to disconnect the switch 64 and cut out the brake coil 34. In the stop position, single stitches are possible by alternate operation of the switch 64. Reference has been directed by the Comptroller to Specifications 779,875 and 779,876.