| 摘要 |
519,866. Damping air - screw vibrations. SARAZIN, R. R. R. Oct. 13, 1938, No. 29690. Convention date, Feb. 28, 1938. [Class 108 (iii)] [Also in Group XXIV] Air-screw vibrations are damped by means exerting a damping force parallel to the rotary axis. The air-screw is axially slidable on its shaft and subject to action of centrifugal masses swinging parallel to the shaft. In Fig. 2, the air-screw 2 is slidable on its driving-shaft 6, being driven through balls 16 which are in apertures in a cylindrical cage 22 and engaging longitudinal grooves 14, 12 respectively in the air-screw and in a sleeve 20 fast on the shaft. Arms 34, transversely pivoted at'30 to the sleeve 20, pass through and engage an extension 40 of the air-screw hub, and carry masses 48 pivoted at 42. Disturbance of the equilibrium between the forward pull of the air-screw and the rearward pull of the masses, by longitudinal forces, is resisted by the inertia of the masses. Pairs of opposite masses may have different natural frequencies to damp more effectively vibrations of different frequencies. Specification 444,222 is referred to. In Fig. 4, the drive is effected through caged rollers 56 round a square-sectioned sleeve ori the shaft. In Fig. 6, movement of the cage 22 is controlled bya lever 66 with its ends in recesses in the screw-hub and the shaft. |
