GB1438938A - Electrical socket assemblies - Google Patents

Abstract

1438938 Two part coupling M K ELECTRIC Ltd 14 June 1973 [30 June 1972 7 Nov 1972] 30732/72 and 51319/72 Heading H2E A shutter on a surface-mounted twin flat-pin socket, maintaining insulated closure of the socket mouths unless plugs are simultaneously inserted in both, comprises shutter plate 18 over socket mouths, operated by plug pins 30. Recesses 24 in cover-plate 12 engage lugs 23 centrally on shutter 18; other lugs 26 projectupward into socket opening 13 in cover-plate 12 with wedge faces so that insertion of plugs forces shutter 18 firstly backwards from the cover-plate and secondly downward (as in Fig. 4), opposed by oblique return spring 32. If only one plug enters, the other end of shutter and projections 23 remain engaged, preventing movement. Rivetted cap plates 34 retain shutter when cover-plate is removed for wiring. In an alternative embodiment (Fig. 5, not shown) the shutter pivots about a central pillar with square retention cap in square recess on top surface of shutter, the pillar being surrounded by the return spring. Wedge action of dual plug entry forces back and rotates shutter, compressing the spring; single plug entry tilts the shutter, preventing clearance of downward projections under the cover-plate and of the square cap, and leaving the other end lug of the shutter engaged, so preventing rotation.