GB1122295A - Improvements in or relating to moulds and processes for the production of electricalfunctional units - Google Patents

Abstract

1,122,295. Encapsulating electrical units. SIEMENS A.G. 3 Feb., 1966 [4 Feb., 1965], No 4706/66. Heading B5A. [Also in Division H1] Electrical functional units of the kind comprising a number of hardenable synthetic resin encapsulated conventional components e.g. a bi-stable multivibrator using two transistors, two diodes, three capacitors and seven resistors and the connecting wires whereof are exposed at the surface of the resin block and connected by printed circuits, are moulded in a mould unit comprising a silicone resin or polyethylene base 2 on which a plurality of injection moulded polystyrene mould wall members 3 are superimposed in each of which the components 23 may be located in a predetermined arrangement by their connecting wires engaging in uniformly disposed grooves 10, of a number thereof, extending from the inside edge 11 on the upper face of each member 3 and which grooves 10 are each intersected by a vertical bore 13 which facilitates the escape of entrapped air from the resin and the testing of the components by contact of a test gauge with the wires thereof after assembly. The bottom wall member (3) is located within a recess (5), (Fig. 9, not shown), in the base (2) which is provided with a plurality of further recesses (6) extending into the underside thereof and which are broken through to the face thereof where required to locate contact wires (22) which extend at right angles into the grooves (10) in the lower wall member (3). Successive wall members (3) are located, via recesses (15) (Fig. 6, not shown) on the underside thereof, on pins (14) projecting from an adjacent lower wall member (3) and which may be staggered to facilitate correct assembly and which location may also, or alternatively, be indicated by exterior projections (16) from each member (3). The electrical components are assembled on each wall member (3) by means of templates, (Fig. 2, not shown), and successive wall members (3) are stuck together by softening the surfaces thereof with solvent or with adhesive foil. To avoid leakage, the resin can initially be cast over the bottom of the mould. After removal of the base 2, the completed moulding is sawn out from the mould to expose the contact wires which may be connected by printed circuits.