GB2039684B - Hinge mechanism for a coin testing mechanism - Google Patents

Abstract

The aim of the invention is to provide a hinge mechanism for a coin testing mechanism which permits adequate separation of two plates, even close to the hinge axis, in conditions where the separation of the plates remote from the hinge axis must be limited. The two plates 12 and 13 are coupled by a hinge pin 19 which passes through slots 21 in lugs 22 on the plate 13 and holes in lugs 20 on the plate 12. A coil spring 23 is disposed around the hinge pin 19 and has its free ends secured to a cantilever leaf spring 28 secured to the plate 13. The slots 21 extend perpendicular to the plate 13 and the springs 23 and 28 co-operate to hold the hinge pin 19 in the bottom of the slots 21. The coil spring has a central loop 24 which bears against the edge of the plate 12 and thus serves to bias the two plates together about the hinge axis. A lever 31 pivoted on the plate 13 carries a cam surface 32 which co-operates with a cam follower surface 35 on the plate 12 so that when the lever is actuated the plates are forced progressively apart by the cam surface riding up the cam follower surface. The coil spring 23 initially allows the plate 12 to pivot about the hinge axis away from the plate 13 but eventually plate 12 strikes an abutment 38 which prevents further rotation of the plate. Further movement of the cam surface up the cam follower surface causes the leaf spring 28 to flex and allow separation of the plates along the edges adjacent the hinge pin 19.