GB941503A - Improvements in and relating to units for rack assemblies - Google Patents

Abstract

941,503. Rack-mounted electrical apparatus. T. N. J. ARCHARD, and M. A. HAMMOND. July 3, 1962 [Nov. 9, 1961], No. 40195/61. Heading H1R. [Also in Division A4] In a unit suitable for mounting in a rack and comprising a main frame accommodating and supporting a plurality of contiguous auxiliary frames, each auxiliary frame comprises at least one side member pivotally mounted eccentrically at its front and rear ends in the frame the angular position of the said member about its pivots determining at least one lateral dimension of the frame. As shown, Fig. 1, a main frame comprises two U-shaped end strips 10 coupled by four supporting bars 12 and a front piece 14. Each auxiliary frame consists of a rectangular front plate 19 coupled to a rectangular rear plate 20 by means of four rectangular tie-rods 21 which are eccentrically pivoted with respect to plates 19, 20 so that when the auxiliary frame is inserted in a screening can, Fig. 2, the tie rods 21 are in the position shown in full lines in Fig. 3; when no screening can is used, the tie rods are in the position shown in broken lines, so that the width and depth of the auxiliary frame are constant. If the strips 30 joining channel sections 29 of the screening can 28 are mounted outside the can they are staggered on the two sides of the can so as to minimize the clearance between adjacent cans. The tie rods 21 may be circular, elliptical &c. Pins 22 on rear plate 20 engage apertures 23 in locator strips 17 to locate the auxiliary frame, and the latter is secured in the main frame by captive screws 24 which engage threaded apertures 25 in the transverse members 15 of front piece 14; spring-loaded catches (not shown) which engage apertures 25 may be used for temporarily holding the frames in place. A chassis or printed circuit board carrying electrical equipment is screwed to the tie rods 21; alternatively, the tie-rods may be grooved to receive the chassis or board. If plastic tie-rods are used they may be provided on each major surface with a pair of parallel projections between which the chassis or board is held; the projections on the outer surfaces of the tie-rods are sheared off so that such tie rods are limited to one of the two angular positions shown in Fig. 3. To connect the equipment in an auxiliary frame with an external circuit, plugs may be let into the rear plate 20 and complementary sockets be provided in plates mounted on further locator strips on the main frame, which may be fitted with top, bottom and side covers. For ease of transportation, the unit may be inserted in a carrying case 35, Fig. 4. In order to tilt the case to facilitate the reading of meters mounted on the front plates 19 of the unit, the case is provided with two telescopic legs 36 which may be secured in a plurality of positions by the engagement of springs in notches in the legs.