GB1274939A - Device for sensing the position of a movable part - Google Patents

Abstract

1,274,939. Non-contact making switches. OLYMPIA WERKE A.G. 18 Aug., 1969 [16 Aug., 1968], No. 41174/69. Heading H3B. [Also in Division G4] The position of a movable member 14 e.g. a key stem of an input key is sensed by the variation in flux in the flux path 12 of a transfluxor 30 caused by a permanent magnet 15 or electromagnet arranged to be movable by the member 14. Initially, when the magnet 15 is in its rest position, current is: passed through winding 27 to magnetize the transfluxor around aperture 17 so that when an alternating signal is applied to interrogate the core no output is obtained from output winding 22. If the magnet 15 is moved into the position shown by dotted lines in limb 12 the transfluxor 30 is unblocked so that when an interrogate signal is again applied to the winding 26 an output is obtained at winding 21. When the magnet 30 returns to its original position the transfluxor remains in its set or unblocked condition. A plurality of the transfluxors 30 each including a plurality of output windings 21-24 of a four unit binary coding may be connected in an input keyboard, Fig. 2. Depression of a key (not shown) results in the corresponding transfluxor core 30 being set so that when an interrogate signal is applied to winding 26 output signals on windings 21-24 gated at 33 by a signal from winding 25 are applied to outputs 41 to 44. The transfluxors 30 may be additionally set by signals from an auxiliary keyboard 31. The arrangement may be used for punched tape readers or in tape punches.