| 摘要 |
1,252,564. Actuators. ENGLISH ELECTRIC CO. Ltd. 28 May 1969, [31 May, 1968], No. 26224/68 Heading B8J [Also in Division F2] A valve actuator comprises an electric motor 2, 4 driving through "pick-off" gears 14, 20 to a worm 34 meshing a worm-wheel 36 which drives a hollow output shaft containing a nut (not shown) engaging a threaded spindle 38 for controlling the valve (not shown). The "pickoff" gear 14 is keyed on its shaft 6 and releasably retained thereon by a circlip 58, whilst the other "pick-off" gear 20 is freely mounted on a sleeve 22 and urged, by a Belleville spring 28 retained by a nut 30, against a friction faced coupling member 26 keyed to the sleeve 22 within which the worm shaft 24 is relatively axially slidably keyed at 32, the combined shaft 24 and sleeve 22 being journalled at 54 and 52 in a casing 8. Relative axial movement between the shaft 24 and sleeve 22 is restrained by a pre-compressed pack of Belleville washers 40 retained by spaced collars 44, 46 on a reduced portion 42 of the worm shaft 24 within the sleeve 22, the collars 44, 46 being seated against the inner splines 32 and a screwed ring 48, respectively. A motor cut-out switch (not shown) housed in an adjacent case 56 includes a rod 57 operated by axial displacement of the worm shaft 24, against the resistance of the spring pack 40, on torqueoverload. |
