Patent GB-854030-A (GB)
Title: Impulse-type electromagnetically actuated devices
IPC: H01H51/01
Filed: 1957-12-06
Abstract: 854,030. Electromagnetic relays; relay actuation. CLEMENTS, W. W. Dec. 6, 1957, No. 38036/57. Class 38 (5). An electromagnetic relay armature is moved to and fro between two stable positions at successive energizations of the operating coil, and an auxiliary magnetic member is moved on each de-energization so as to set the relay for the next operation. As shown in Figs. 1 and 3 the coil 1 surrounds a core 2 attached at its lower end to a U-shaped magnetic member 7 having pivots 15 for the U-shaped armature 12 which engages a stop 19 on the top of the core 2. An auxiliary member 3, pivoted at 4 to a fixed support 6, carries two magnetic shoes 9L, 9R and has a projection 17 above the pivot 4 which is coupled by a spring 18 with a projection 16 on the armature. When the coil 1 is energized the armature 12 is attracted away from the Fig. 1 position by the shoe 9R which is in contact with the core 2. During this movement the spring 18, whose ends are biased apart, passes a dead-centre position and tends to rotate the member 3 to bring its other shoe 9L into contact with the core 2 but this cannot take place until the coil is de-energized, whereupon the parts assume the Fig. 3 position. On the next energizing impulse the operation is reversed. In Fig. 5 two series or parallel coils 21 have cores magnetically connected by a strip 22A and the armature 31 is pivoted at 24. The armature has a contact-arm 36 coupled by a spring 38 to the auxiliary member 28 arranged so that the spring tends to retain the latter symmetrical in relation to the armature. The magnetic shoes 29L, 29R of the member 28 pass through holes in the armature to engage poles 30L, 30R. When the coils are energized the armature is attracted to the pole 30R since its gap at the other pole remains substantially unaltered owing to the presence of the shoe 29L. During the movement a pin 39B on the arm 36 passes the lowest point of a bent spring strip 39A and is retained in its other stable position. The spring 38 biases the member 28 so that it tends to follow the armature but is held until the coils are de-energized. In a modification of this arrangement the armature may be biased to its stable positions by a snap-action spring strip (Fig. 14, not shown). The armature and member 28 may be U-shaped with their ends engaging poles of a straight core surrounded by a single coil (Fig. 11, not shown). In a further modification (Fig. 12, not shown), the U-shaped armature and member may each be formed of three separate limbs, the outer limbs being pivoted at each end of the coil and mechanically linked. In Fig. 8 the coil 41 is surrounded by magnetic members 42A . . . 42C and a non- magnetic tube 61 contains the armature 51 which is coupled to a contact 60A and a snapaction spring strip 59. The auxiliary member 43 is " centred " by springs 58 and has two magnetic shoes 49L, 49R connected by the bent part 48 which is guided for rectilinear movement by pins 44. When the coil is energized the armature 51 and member 43 move together straining one spring 58 and the spring 59 snaps to its other stable position. When the coil is de-energized the strained spring 58 moves the member 43 so that the shoe 49R comes into contact with the armature. Alternatively (Figs. 16 to 18, not shown) the shoes 49L, 49R may be coupled by non-magnetic strips passing through slots in the armature and contacts may be mounted on projecting ends of the snapaction spring 59.