GB610241A - Improvements in and relating to cased transformers, chokes and the like - Google Patents

Abstract

610,241. Transformers and inductances. BRYCE & CO., Ltd., W. A., and ATKINS, J. A. April 2, 1946, No. 10158. [Class 38 (ii)] To facilitate the assembly and encasing of transformers, chokes and the like provided with conventional laminated cores and windings the core clamping members are provided with attached cages in which are trapped loose nuts adapted to receive studs or bolts which clamp the laminations together and/or secure the casing thereto, the nuts being prevented from turning in the cages while having freedom for some lateral movement. Fig. 1 shows a transformer sealed within a biscuit-tin type casing which consists of a body portion 1 of rectangular cross-section open at both ends, and flanged top and bottom panels 3, 2 respectively. (One side is shown cut away to reveal the interior.) The core clamping members consist of angle-brackets formed by bending blanks 11, Fig. 10, at right-angles along lines 11h to form side flanges 11a, 11b, and top and bottom lugs 11d, 11e, the flanges 11a having elongated holes 11c to receive bolts 9 which pass through corresponding holes in the core 7, and the lugs 11e having inset portions on opposite sides around which metal tabs on the cages 14 are bent to secure the latter in position. The cages are in the form of small openbottomed boxes made from sheet metal blanks, and a square nut 15 is located in each of them before it is seated on and attached to its respective lug 11e. In assembling the parts, after clamping the core 7 by a bracket 11 along each corner the upper lugs 11d of the brackets are secured to the top panel 3 of the casing by studs 4 and nuts 12, and the ends of the transformer windings are connected to terminals 5 on the top panel, after which the open-ended casing 1 is slid over the transformer and its upper edges disposed underneath the side flanges of the panel 3. The bottom panel is placed in position and held by studs 4 which are inserted through holes therein to engage nuts 15 within the cages 14. The studs are provided with flanges 4a which may be soldered to the casing after assembly, and the flanges of panels 2, 3 may also be soldered to the body 1 which they overlap. The nuts 15 have a conical countersunk hole or " lead " to enable them to be picked up readily by the studs 4.