GB568509A - An instrument for recording surface roughness - Google Patents

Abstract

568,509. Recording surface roughnees. TOMLINSON, G. A. March 23, 1943, No. 4702. [Classes 106 (ii) and 106 (iv)] An instrument for recording surface roughness comprise a feeler 4 which has a rounded end 5 contacting _the surface, the feeler being movable longitudinally in a base 2 provided with a sole, plate 1 to rest on the surface. The rounded end 5 of the feeler is large enough not to be influenced by minor roughness and the sole plates span a considerable number of the roughness crests to be recorded. The feeler 4 passes through a disc 3 secured to the sole plate 1 and has adjustably attached to it a second disc 6. The two discs are connected by three springs 8, inclined to the axis of the feeler so that as the feeler moves longitudinally, it is also caused to have a rotational motion, this motion being transmitted to a recording arm 10 to make a record on a smoked plate on a table 16 slidable along guides 12, 13. As the instrument is moved to explore the surface under test, the record table 16 is given a similar but reduced motion by a cord 23 attached to a fixed point 24 and operating a lever 20 pivoted at 21 and engaging a pin 22 on the table. The instrument is balanced by a weight 28 on an arm 30. The weight 28 may be replaced by a guide plate 31, Fig. 2, when the instrument is to be used on a convex surface. For use on a concave surface, support is obtained by providing two bars below the longer edges of the base 2.