GB770951A - Improvements in or relating to apparatus for detecting slip between movable members - Google Patents

Abstract

770,951. Endless belt conveyers. GENERAL ELECTRIC CO., Ltd., and SPENCER, P. L. April 14, 1954 [April 16, 1953], No. 10436/53. Class 78 (1). [Also in Group XXIV] Apparatus for detecting when slip between a conveyer belt and its driving roller exceeds a predetermined value comprises two members coupled to the belt and roller respectively and arranged to move at the same speed when the slip is equal to said predetermined value, and means for detecting relative movement between said members when the slip exceeds the pre. determined value. In Figs. 1, 2, the driving pulley 11 of a conveyer belt 10 and a snub pulley 12 engaging the belt are connected through gearings 13, 15 to a disc 20 and annulus 21 respectively, the gearings being such that when a predetermined slip occurs between the pulley 11 and the belt, the disc and annulus rotate in the same direction at the same speed. If the slip becomes greater than this predetermined amount, the disc 20 rotates anticlockwise relatively to the annulus 21, whereby a sprung arm 23 secured to a block 22 on the disc engages a spring-loaded finger 26 pivoted at 27 and is deflected against a contact 25 so as to operate an indicator or shut down the driving motor. If the belt is driven in the opposite direction, the arm will engage a contact 24. Instead of using the gearing 13, 15, the size of the pulleys 11, 12 may be so arranged as to cause rotation of the disc 20 and annulus 21 at the same speed. In a modification, Figs. 3, 4, the gearings 13, 15 are connected to shafts 40, 41 of a differential gearing which, when the slip is equal to the predetermined value, rotate at equal speeds in opposite directions. When the slip exceeds this amount, the differential cage 46 rotates clockwise whereby teeth 47 on the cage engage pawls 52 pivotally mounted on a ring 50, so as to rotate the ring and bring projection 55 into engagement with the actuating plate 57 of a switch 58 and operate a motor control member or provide a warning. The invention may be used for indicating slip between a driving belt and a driven pulley or for indicating when the slip between two elements of a friction drive exceeds a predetermined amount. Specification 719,136 is referred to.