| 摘要 |
1,155,131. Magnetic couplings. STEWARTWARNER CORP. 29 June, 1966 [30 June, 1965], No. 29213/66. Heading H2A. Apparatus for deriving a substantially constant speed output from a variable speed input device comprises a rotatable shaft driven by a hysteresis drive, and an eddy current device to supply a retarding torque to the shaft proportional to its speed, to maintain its speed constant at speeds above a certain low speed, and means for adjusting the position of the eddy current device axially of the shaft for selecting the constant speed. As shown, the eddy current device consists of an aluminium or copper cup 24 surrounding an output shaft 18 and extending between a discshaped permanent magnet 16 on output shaft 18 and a hardened steel cup 14 on an input shaft 10, forming a hysteresis coupling. The speed of shaft 18 above, e.g., 400 r.p.m., may be selected by adjusting the position of cup 24 axially on a boss 22 which with it has threaded engagement. The output shaft drives a clock 34 or hour meter constituting a fixed load torque which is a negligible proportion of the total torque above the "certain low speed" mentioned above. The invention enables the escapement of the clock or meter to the dispensed with. In a modification the eddy current cup 24 and boss 22 are separate from the hysteresis coupling 14, 16 and are associated instead with a further magnet fixed to the output shaft intermediate its ends. A steel cup secured to the shaft 18 to serve as a flux return path faces and surrounds the eddy current cup and its magnet. Reference has been directed by the Comptroller to Specification 1,009,501. |
