ES361562A1 - Mechanically actuated warning device - Google Patents

Abstract

Door chimes comprise plates B, C sounded by a hammer D which is operated by a dead-centre mechanism comprising a conically-shaped cam F secured to a push-button which causes an arm 8 and hence hammer D to which it is connected by a spring 10, to swing between plates B, C. Arm 8 is spring biased against cam F and the push button is spring biased outwardly of the housing (A, Fig. 1, not shown) so that hammer D always returns to the position shown in Fig. 1 in solid lines. In alternative embodiments of the dead-centre mechanism (Figs. 7-9, not shown) arm 8 is connected to hammer D by a fork (30) engaging a lug (31) or a large aperture (40) engaging a lug (41), and spring 10 is connected between hammer D and the base of the housing A. Alternatively, arm 10 may be connected to a lug on the hammer-arm 6. In all embodiments, adjustable stops 14 act against spring 10 to prevent hammer D resting against plates B, C. Plate B preferably produces a lower note than plate C. Both plates are supported (Fig. 3, not shown) on preferably nylon foam washers clamped by wires around their centres to pins 4, for acoustic insulation. Slots (26) improve the resonance of housing (A) (Fig. 6, not shown), whose base (1) is screwed to a door (P). A peephole (25) in housing (A) (Fig. 1, not shown) is coaxial with spyglass lens mounted in the tubular push button, which is prevented from being wedged by arm 8 by spring 11a.