GB758782A - Improvements in electromagnetic relays - Google Patents

Abstract

758,782. Electromagnetic relays. WESTINGHOUSE AIR BRAKE CO. July 20,1954 [July 24, 1953], No. 21086/54. Class 38(5) A relay similar in many respects to that disclosed in Specification 708,985 comprises a magnetic shell 2 surrounding a core 7 and winding 8, a four-armed armature 16 having a spindle 18 being pivoted on the core, the armature arms 22 co-operating with pole pieces 13 carried by a non-magnetic plate 10. The shell 2 together with a disc 3 welded thereto forms a sealed enclosure, contactcarrying posts 5 being mounted in glass beads 4 in the disc. An insulating contactactuating spider 17 secured to the armature hub 21 has six notches 28 formed in its upstanding peripheral wall 25 which engage the extremities of respective spring contact fingers 33 having contacts 37, 38. When the coil 8 is not energized the bias in the fingers 33 holds the contacts 37 against back contacts 31, energization of the coil causing the ends of the notches 28 to flex the fingers so that contacts 38 engage front contacts 32, this engagement taking place before the arms 22 engage the pole pieces 13. To prevent rebound of the armature on back stops 12 when the coil is de-energized the spider 17 has a peripheral groove 29 frictionally engaged by a resilient inertia ring 30 whereby when the armature is arrested by the stops 12, the ring 30 continues to rotate and exerts a force on the spider to hold the armature against the stops. The ends of the fingers 33 are bifurcated and of unequal length, the longer upper tips 35 co-operating with the notches 28. To allow for contact misalignment the surfaces of the contacts 31, 32 are arcuate about an axis at right angles to that about which the surfaces of contacts 37, 38 are arcuate.