GB1105319A - Improvements in and relating to apparatus for determining the co-efficient of friction - Google Patents

Abstract

1,105,319. Friction tests. C.N. ROWE. Aug. 31, 1965 [July 15, 1964], No. 29041/64. Heading G1S. A self-contained portable unit for measuring the coefficient of friction between a standard surface and another surface comprises a housing 9, 10, 11, a carriage and a drive for moving it at a steady speed within the housing, a shoe 52 on which the standard is provided and which is connected to the carriage through a spring device 47, 49 and an indicator 34 mounted on the carriage and indicates the stress in the spring device, the arrangement being such that in use the stress in the spring device provides a corresponding tension tending to pull the shoe along the other surface and as the carriage moves the stress and tension increase until the friction between the standard and other surface is just overcome whereupon the indicator registers at the moment of movement a value dependent upon the limiting friction between the two surfaces. The carriage slides on guide rods 14, its movement being limited by rubber headed stops 19, 20 engaging side flanges 16, 17. The carriage is urged to move to the right by a coiled spring 21. The movement of the carriage is dampened by a dashpot cylinder 27. The live pointer 34, with a slave pointer 35 is mounted on a spindle 39 having a drum 42 rigidly fixed thereto. The measuring operation is started by pressing control knob 58 which through a lever system releases the carriage for movement by spring 21. The shoe 52 will not move immediately because of the frictional force and hence the drum 42 is rotated by the force in rod 47 building up stress in spring device 45, 49, carrying the pointers 34, 35 over the scale. When the frictional force is just overcome the shoe will suddenly move relieving the stress in the spring device so that the drum and live pointer 34 rotate back to zero position. The carriage will continue to move and the cycle will be repeated until the carriage reaches abutment 20. The slave pointer 35 will record the maximum frictional force and the scale may be calibrated directly in coefficients of friction.