GB908580A - Position and orientation detector for a lift cage or the like - Google Patents

Abstract

908,580. Detecting the position of skips or cages in shafts. PEEBLES & CO. Ltd., BRUCE. Feb. 1, 1961 [Nov. 4, 1959], No. 37462/59. Class 78 (4). A retractable member in the shaft of an unguided lift cage or mine skip co-operates with the cage or skip to give a signal which is operative only if the cage or skip has a predetermined orientation about a vertical axis and is at the same time at a predetermined level in the shaft. The retractable member in Fig. 1 comprises two parallel arms 22 pivotable together about an axis 23 from a retracted position parallel to the walls of a mine shaft 13 into the position shown in which they embrace the skip 11. If the skip is at the predetermined level and orientation, both the electromagnetic cores 16 carried by the respective arms 22 will embrace corresponding ferromagnetic armatures 15 on the skip so that a signal is derivable from windings on each of the cores. These signals form the inputs of an AND logic system which gives an output only if both inputs are simultaneously present. The retractable member in Fig. 3 is a U-shaped frame 30 which is horizontally slidable to embrace the skip 11 which, if it is at the predetermined level and orientation, depresses a plunger 34 which releases a catch to allow spring-biased movement of a ferromagnetic armature into a position embraced by the fixed core of a detector of the type comprising an armature and core such as 15 and 16 in Fig. 1, this detector being wholly carried by the frame 30. The means for moving the frame 30 into skip-embracing position comprises a fluid-pressure ram 27, the actuation of which is followed by that of a second such ram 37 by which the system of levers 38, 39, 29 are moved from the position shown into one in which projections 31 on levers 29 engage recesses 32 on the skip to hold the latter in the said predetermined position. This skip-holding condition may be detected and signalled by a further armature-and-core detector arranged in an AND logic system with the detector actuated by plunger 34, so that loading of the skip when controlled by the output of this AND system can only take place with the skip firmly held at the predetermined position and orientation. Specification 860,396 is referred to.