Importance

Loading Importance Indicators...

Abstract

A descent slowing device is disclosed that includes a housing having an input driving shaft and a driving pulley fitted thereon and accommodating therein a gear train and an impeller adapted to be driven through the gear train by a driving pulley about which is trained a rope or line. When one end of the line descends owing to a load acting thereon to rotatively drive the driving pulley and hence the impeller, the rotation of the impeller is restrained by rotation control oil or similar viscous fluid in which the impeller is immersed, thereby controlling the descent of the load at a constant slow speed. According to the invention, the impeller comprises four blades, the rotating speed ratio of the impeller to the input driving shaft being more than 40:1. Moreover, the driving pulley is formed with a rope receiving groove comprising line abutting projections and non-contact recesses alternately arranged. There are provided a stationary pulley and pendulum pulleys, the line passing between the pendulum pulleys, respectively, and the stationary pulley to cause a frictional compression of the rope between one of the pendulum pulleys and the stationary pulley. Descent is thus controlled if the load is very large, and line slippage is avoided. With the above arrangement, the device according to the invention operates smoothly and securely even after long unused periods of time, under continuous load conditions, and at high or low temperature conditions.

Loading the Abstract Image...

First Claim