GB1528181A - Overload system for a mechanical device - Google Patents

Abstract

1528181 Breaking-pieces ALFRED HERBERT Ltd 16 Dec 1975 [14 Jan 1975] 1454/75 Heading F2X A shearable component such as a shear pin 5 for use in an overload system for a mechanical device, e.g. a machine tool, has a blind bore 8 therein traversing one or more predetermined planes of shear defined by one or more peripheral grooves 7. A portion 9 of the blind bore 8 is enlarged and threaded to receive a union 10 connecting a fluid supply pipe 11 to the bore 8. As shown in Fig. 1, the shear pin 5 is used to connect a roller 4 to a bifurcated cam follower arm 1 and has two grooves 7. If the pin shears at either of the grooves 7, the shear occurs across the bore 8 which then becomes openended. A number of pins 5 may be supplied in parallel from a common pressure source (Fig. 4, not shown) with a pressure-sensitive switch incorporated in the circuit. The switch is in its operative position when pressure is maintained in all the pins 5 but assumes an inoperative position and thereby breaks an electrical circuit, e.g. to a motor driving a cam shaft actuating the arms 1, when the circuit becomes depressurized, as would occur should one of the pins 5 shear due to an overload. The system could also be arranged to give a remote alarm indication of failure of one of the pins by using the pressure-sensitive means, or by separate means.