Patent GB-275255-A (GB)
Title: Selectors
IPC: H01H67/12
Filed: 1927-07-29
Abstract: 275,255. Merk, F. July .30, 1926, [Convention date]. Selectors.-In a selector involving group and individual contact selection, both operations are effected by a setting member which is moved in the same direction and in steps of equal length by a single stepping mechanism. The invention is described as applied to a panel switch of the brush-choosing type. Each brush-set a, b, c1, c2, Fig. 2, of a vertical row, is mounted on a carriage comprising three bars 12, 13, 14 and carrying guide members 28 adapted to slide in slots in a frame mounted on the face of the panel. A common guide frame 35, Fig. 11 is used for a panel. Each brush set comprises two inner brushes C1, C2, Fig. 2, electrically connected to the central bar 13 and having backwardly extending tongues adapted to engage the lateral edges of the bank contacts b<1>, and a pair of outer brushes a, b which rest upon insulating pins 33 on the inner brushes c1, c2, and are formed with tongues for wiping over the edges of the contacts a<1>, c<1>. The tension of all the brushes urges them towards the centre bar 13, but they are normally held outwardly and clear of the contacts by tongues 15 on a spring 16, the tension of which holds it against the bar 13. The end of the spring 16 is bent over horizontally to for a projection 20, Fig. 5, provided with a slot 18 through which passes the bar 13. The brush sets are displaced relatively to one another on the sliding carriage, in such a manner that one step brings the first set in front of the beginning of the first contact group, two steps brings the second set in front of the beginning of the second contact group, and so on. Tripping fingers 34, Fig. 1 are mounted opposite the beginning of each contact group on a rotatable spindle 32 which is turned by a magnet, after the first stepping operation has brought a certain brush-set to the beginning of the wanted group, to cause a tripping finger 34 to strike the projection 20, Fig. 5 and press back the spring 16 of this brush-set to a, position in which the tongues 15 fall into apertures 19, Fig. 7, in the brushes c1, c2. The brushes thereby assume their effective positions and during the next stepping movement wipe over the contacts. Electrical connection is maintained with the brushes through springs 31, Fig. 9 which wipe over the bars 12, 13, 14. The upper and lower covering plates of the horizontal bank sections of contacts are provided with lateral extensions which fit into recesses in the end uprights of the panel where they are held by covering strips 41, Fig. 11. The stepping magnet 21, Fig. 9 with its stepping and holding pawls 38, 39 is mounted on a frame plate 37, the ratchet bar 24 being slidably mounted between two guide bars 22 and being adjustably secured to the brush carriage by a member 25. On release, the carriage is stepped on until the brushes c1, c2 of the tripped set engage a spreader 29, Fig. 11 at the top of the contact group. The brushes c1, c2 are then forced apart to move all the brushes to their non-wiping positions where they are held by the spring 16, Fig. 2, which resumes its normal position against the bar 13. The Specification as open to inspection under Sect. 91 (3) (a) states that the spreaders 29 may be adjustably mounted upon the individual guide frames for the brush carriages, and that the invention is applicable to switches in which the single stepping movement first acts upon a rotary brush choosing element, or in which the brushtripping members slide upon the brush carriages. This subject-matter is not included in the Specification as accepted.