| 摘要 |
<p>The drive train to the operating parts of a sewing machine incorporates an electromagnetic brake and clutch system. The clutch plate is of a ferro-magnetic material, and is fitted with a friction cladding. It is mounted to the driven shaft with the help of flexible and sprung discs between the clutch plate and the shaft, so that the plate can slide axially along the shaft, while the flywheel on the drive shaft lies opposite the friction cladding of the clutch plate. A fixed electro-magnetic unit is energised to press the clutch plate against the surface of the flywheel. A rigid brake disc of a ferro-magnetic material and fitted with a brake lining, is fitted to the driven shaft. An electro-magnetic unit acts together with the brake lining and the limit surface attached to the housing, and flexible sprung discs between the housing and the electromagnetic unit, so that when it is energised the electromagnetic unit moves along the driven shaft and can be controlled to retract from the brake disc. A threaded ring has its thread engaged in the housing, and slides along the driven shaft under controlled rotation to bear against the limit surface and to bring it to or from the break disc. The design allows an adjustment to give the optimum gap between the brake lining on the brake disc and the corresp. surface while the electro-mtoro is running and the machine shaft is rotating.</p> |
