GB1445615A - Foot-operated control device - Google Patents

Abstract

1445615 Actuation of switches & rheostats; electric motor control SIEMENS AG 20 June 1973 [26 June 1972] 29397/73 Headings H1N and HIS A foot-control device, Fig. 1 as used for actuating dental apparatus comprises a housing 1 from which projects an actuating member 2 provided with foot application means 3 movable in a horizontal plane, a footplate 16 and three depressible actuating elements 4, 5, 6 for control elements such as a rheostat and electrical switches situated within the housing. As shown in Fig. 2 the actuating member 2 is T-shaped with the lines joining the extremities of the T forming a notional isosceles triangle. At the ends of the crossbar 9 are attached pivot pins 10, 11 which can slide in guideways 12, 13 and when the foot application means 3 is deflected against restoring action of a spring 16 to either side of its basic position represented by line 14 it describes a predetermined curved path away from the base line of the notional triangle as represented by lines radiused R 1 and R 2 . In another embodiment, Fig. 4, the pins and guides are replaced by V-shaped notched bearings 23 ... 26 of which the V-blocks can be fixed to the baseplate 28 as shown or provided in the ends of the T-crossbar but either arrangement enables the foot application means 21 of the actuating member 20 to be depressed downwards against the action of a common restoring spring 27 to operate a switch 31 when the member 20 is in its basic position. Also in the Fig. 4 embodiment the footplate 40 is hinged about an axis 45 to actuate a switch 48 by downward pressure. The remaining internal features shown in Fig. 4 also apply to Fig. 1 and comprise a rotary potentiometer rheostat 30 and further switches 43 and 44 actuated by a plate 33 of the actuating member when in an operating end position in which position it can be retained by permanent magnets 41, 42 acting on an armature 32. The potentiometer which is used for speed control of an electric motor drive is driven by a pin 36 attached to the actuating member acting in the slot of an arm 35 which is attached to the potentiometer pivot. Suitable functions for the other switches and control elements are described with reference to the drive for a dental drill. A further embodiment (Fig. 5, not shown) describes a pivotal bearing arrangement for the actuating member in the manner of a double-acting swing door hinge. Specifications 1,445,612, 1,445,613, 1,445,614 and 1,445,616 are referred to.