GB190006920A - Improvements in Cranes and Hoisting Apparatus. - Google Patents

Abstract

6920. Williams, A. E. April 12. Cranes.-The carriage a carrying the jib g runs along rails b on the side of a jetty. The lifting- rope passes from the winding-drum n around a pulley i at the end of the jib back to a travelling carriagej, around a pulley on which it passes to the usual skip p. The pulley l is mounted in a frame free to rotate about an axis parallel to the jib. Upon the axle of the drum n is also mounted a second drum 19, from which a rope 20 passes over pulleys at the top of the crane to a balance weight 22. A rope r attached to the inner end of the car j passes to a drum S, from which also a second rope passes to a balance weight z, which thus in the absence of a load tends to move the carriage j inwards along the jib. A load, however, overcomes the weight z, and forces the carriage j to the outer end of the jib, where it may be secured by a catch. For unloading a ship into a barge, therefore, as shown, the carriage runs automatically in and out. The jib is balanced by a weight on an arm 2 connected to the jib by a rope 4, in such a way that the movement of the weight varies with the movement of the jib. The pulley i at the end of the jib may have sliding bearings, and be fitted with a ram working in a cylinder in communication with a pressure gauge so that the weight of the load may be estimated.