GB284809A - Improvements in electro-magnetic movements for relays, signal repeaters, track indicators and the like - Google Patents

Abstract

284,809. Automatic Telephone Manufacturing Co., Ltd., and Tarrant, R. W. Nov. 25, 1926. Indicators and annunciators and like single indication signalling devices; order apparatus.- An electromagnetic movement has armatures which are adjustable to facilitate the use of the movement as a two- or three-position indicator or relay. In the three-position indicator shown, the armatures 10 of the electromagnets 6 are frictionally mounted on a non-magnetic spindle 9 which is pivoted in a U-shaped frame 1 and carries an indicating arm 11. The armatures 10 are polarized by a U-shaped permanent magnet 3 and the arm 11 may be operated into positions on either side of its normal position by energization of the electromagnets 6 by reverse currents. The armatures are adjustable with respect to the electromagnets by sliding them along or rotating them about the spindle 9, and in this manner the apparatus may be adapted for maximum operation at a particular current value or over a range of current values. The apparatus may be mechanically biased to adapt it for use as a twoposition indicator by rotating one of the armatures into a position outside the influence of the electromagnets. Alternatively a special balance weight or the weight of the indicating arm may be utilized. The apparatus also may be adapted for use as a two-position indicator having no normal position. As applied to signal repeaters, or track indicators for railway signalling, the mechanical bias is arranged to bring the indicator into the " wrong " or " track occupied " position. The indicating arm may be replaced by a contact arm to adapt the apparatus for use as a relay.