Improvements in grab-buckets

Abstract

Abstract 347,472. Grab buckets. UNRUH & LIEBIG, ABTEILUNG DER PENIGER MASCHINENFABRIC UND EISENGIESSEREI AKT.-GES., 28, Naumburgerstrasse, Plagwitz, Leipsic, Germany. April 15, 1930, No. 11943. Convention date, April 19, 1929. [Class 78 (iv).] Grab-buckets of the type in which an electric motor is mounted on the grab itself are characterized in that hydraulic transmission mechanism is used between the motor and the scoops. Fig. 3 shows a motor e, a pump g driven thereby through gearing f, an oil tank t and valve mechanism i all mounted within a casing c to which the scoops a are pivoted at b. Cylinders d are mounted on one of the scoops a, the piston rods which they operate being located on the opposite scoop. As shown diagrammatically in Fig. 4, the valve mechanism i comprises three chamber i<1>, ill, i<111> through which passes a rod m which is operated by an electromagnet k and provided with valve members n, n<1>, the position shown being such that the chambers i<1>, ill are in communication but isolated from the chamber i<111>. Oil passes from the tank t through the pump g, chamber i<1>, pipes 7 .. 10 and cylinders d to the rear sides of the pistons h, also through the chamber ill, pipes 3 .. 6 and ducts p within the rods o to the front sides of the pistons ; the front sides being of larger area, a differential pressure effect is obtained and the scoops are opened. When the rod m is operated so that the chambers i<11>, i<111> are connected but isolated from i<1>, pressure on the front of the pistons through i<11> is cut off, and the pressure on the rear side closes the scoops, oil being forced from the cylinders through the ducts p and chambers ill, i<111>back to the tank t. The motor is operated simultaneously with the magnet k, and a safety valve is provided.

Inventors

No inventors recorded.

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