| 摘要 |
<p>A linear actuator (10) has reversible electric motors (21,22) in a housing (23) driving a screw-threaded shaft (13) engaging a roller nut (14). A tubular housing (15) attached to the nut (14) has at its remote end an internal seating (16) and load securing lugs (29). An hydraulic shock absorber unit (17), giving linear deceleration, is normally held in its most relaxed condition between the seating (16) and an end of a spacer tube (30) butting against the nut (14). When the nut (14) is within the shock absorber stroke distance of the driven end (19) of the shaft (13), the free end (18) of the shaft (13) compresses the shock absorber unit (17) against the seating (16). When the nut (14) is within shock absorber stroke distance of the free end (18), a ring (37) engages a stop collar (41), thereby holding the shock absorber body (35) at a fixed distance from the end (18), and the spacer tube (30) compresses the shock absorber unit (17). A centrifugal brake (80) (Figs. 8 and 9) is provided on a drive coupling pulley (27). <IMAGE></p> |
