GB896256A - Improvements in or relating to a position indicator - Google Patents

Abstract

896,256. Electric selective signalling systems. SCHWEIZERISCHE WAGONS-UND AUFZUGEFABRIK A.G. July 8, 1958 [July 22, 1957], No. 21920/58. Class 40 (1). [Also in Group XXX] A device for indicating the position of a moved object with one degree of freedom. e.g. a. lift car (see Group XXX), comprises a magnetic storage element having two stable states of magnetization determined by magnetic actuating elements moved relatively to the storage element so that, according to the direction of passage of an actuating element, one of said states is produced in the storage element and this state is detected and converted to an electrical signal. As applied to a lift system, on passing a magnet 9 in the shaft a magnetic element 1, mounted on the car, has its polarity changed thereby reinforcing or opposing the magnetic flux in an element 5, and so varying the inductance of a coil 8 which is connected in a control circuit where the variation of current flowing through coil 8 indicates the position of the car. In a modification, Fig. 2 (not shown), the element 5 is replaced by a semi-conductor which registers a change in potential when the magnetic field between magnets 1 and 4 changes. In a further modification, Fig. 5 (not shown), the magnetic element is in the form of a loop, the element 5 is in the form of a toroid and to render the element 5.more sensitive to the direction of the magnetic flux between the ends of the element 1, an additional magnetic element is provided.