Patent GB-1105462-A (GB)
Title: Device for rendering control of operating apparatus unaffected by accelerations
IPC: H01H50/30
Filed: 1965-05-07
Abstract: 1,105,462. Electromagnetic relays. LA TELEMECANIQUE ELECTRIQUE. 7 May, 1965 [8 May, 1964], No. 19476/65. Heading H1N. [Also in Division F2] A mechanical device which, when it is rigidly fixed to the moving part of an operating mechanism, e.g. the armature of a magnetic relay or contactor, renders it insensitive to shocks comprises a plate 3, which represents the frame of an operating device and which is pivoted about a shaft on a table 1 guided between slides 2A, 2B and subjected to very high acceleration forces F, the plate being coupled to the table 1 by elastic means 5 so that it can oscillate about a mean position of rest H, H 1 . The mechanism, e.g. the contacts of an electric relay, coupled to the moving frame 3 and which are subject to its vibrations, is composed of two rotors 6, 7 rotatably mounted on shafts 8, 9 located on reference H, H 1  and having engaging peripheral teeth 6A, 7A. If only one statically balanced rotor (6) is used, Fig. 3 (not shown), vibrations of the plate of frame (3) about the reference (H, H 1 ) causes a relative rotational displacement (α) between the plate (3) and the rotor (6), the reference marks (12, 13) lying on different diameters of the rotor except at the instant the plate is passing through the horizontal reference (H, H 1 ). However, in the case in Fig. 1 (not. shown), where two statically balanced rotors (6, 7) are employed the references (12, 13) remain aligned on a single diameter of the rotor (6) as the plate (3) oscillates about the shaft (4) since, with the two rotors tending to rotate in opposite directions, the inertia couples are of equal and opposite sign and cancel each other out at the point of engagement of the teeth (6A, 7A). It is necessary, and sufficient, that the ratio between the radii of the pitch circles of the two rotors is equal to the ratio between the moments of inertia of the two corresponding rotors. Two identical rotors can be mounted upon a single axis and located in two parallel planes, at the rotors being connected by at least one reversing pin so as to rotate in opposite directions. The reversing pinion should either be made of light material or preferably it should be balanced by a contrarotating pinion of identical construction and mounted symmetrically. In a first embodiment, Fig. 4, an apparatus, comprising a frame 15, a yoke with two poles 16A, 16B, a central core 19 and an axial coil 17, two rotors, each constituted by a magnetic element 20A, 20B, are rotatably mounted on the core 19 and carry two toothed pinions 23A, 23B which are made of non-magnetic material and which engage at least one reversing pinion 24 having a shaft 25 mounted in a bearing 26 fixed to the frame 15. Contacts 30 are movable between the "on". and "off" positions 30B, 30A respectively by means of rollers 31A, 31B which work in helicoidal ramps 28A, 28B in a cylinder 27 carried by the shaft 25. The position of rest of the contactor 30 is ensured by a spring 32, and over-travel stops (36, 37), Fig. 5 (not shown), are provided. In a second embodiment, Fig. 8 (not shown), e.g. for alternating current, the flux is provided by two coils (17A, 17B) mounted on two fixed yokes (16A, 16B) forming cores, the contact operating system, which is the same as that described with respect to Fig. 4, being taken from the shaft (25) of the bevel pinion or from one of the rotors. A second bevel pinion could be arranged between the pinions (23A, 23B) symmetrically with respect to the first pinion. The shaft (25) can carry a cam (41), Fig. 10 (not shown), for operating the contacts instead of the cylinder with the helicoidal ramps 31A, 31B, as shown.