GB767670A - Device for defective vibration - Google Patents

Abstract

767,670. Detecting vibrations. ROLLSROYCE, Ltd. Nov. 25, 1955 [Nov. 26, 1954], No. 34421/54. Class 106 (4). A device for detecting a vibration having an acceleration greater than a preselected value comprises a movable element or beam 4 pivotally mounted on a part of or on a part connected rigidly to the vibrating mechanism the beam having a considerable mass 3 substantially concentrated at its centre of gravity 30, a first contact 6 rigidly connected to the beam, a cooperating contact 31 carried on the fixed part, resilient means, e.g. the spring 19 to load the beam to close the contacts and a circuit the breaking of which at the contacts 6, 31 causes the operation of a warning or control device, the arrangement being such that when the vibration of the mechanism has an acceleration above the preselected value the beam will oscillate to break the contacts preferably so that they " bounce " in such a manner as to be open for a large proportion of the time. As shown, the beam 4 is tubular and elastic, preferably of steel, and the distance between the contacts and the centre of gravity is about ten times the distance between the centre of gravity and the pivot axis. Bolted to the mass 3 are a pair of fulcrum blocks 9 having pins 14 pivotally supported in the casing. The fulcrum blocks 9 are generally cylindrical but are cut to semi-cylinders centrally to allow them to be telescoped into each other inside the groove 8 during assembly. The load on the spring 19 may be varied by a nut 23 adjusting the spring lengthwise of a pillar 21. A lever 39 mounted on a spindle 38 operated by an external handle has a spring- loaded tappet 40 which may be raised into contact with the beam 4 to open the contacts 6, 31 for test purposes.