GB247706A - An instrument for continuously indicating or recording tensile and compressive strains - Google Patents

Abstract

247,706. Taylor, J. L. Dec. 29, 1924. Linear - dimension gauges. - Comprises an extensometer in which a spring blade is subjected to either the compressive or tensile strain to be measured and arms secured to the end of the blade move angularly relative to each other to effect an indication or record. The spring blade c is initially bent and arranged between the ends of two longitudinal members a, b arranged within a tubular guide d formed with oppositely arranged longitudinal slots. The member a is fixed to the tube while the member b slides without turning in the tube and is made variable in length by making it in two screwed lengths connected by a turnbuckle f. Loclmuts f<2> serve to secure the lengths in any adjusted position. The end of the tube receiving the member a is threaded to receive an adjustable screw a which forms a fine adjustment for the length of the device. The inner ends of the members a, b may be formed with hardened anvils grooved to receive the ends of the spring blade. To these ends are secured arms g, h to the former of which is pivoted a scale plate i which is engaged by the end of the latter arm which forms an index. In a modification, a graduated disc is pivoted to the end of the arm g adapted to be rotated continuously or intermittently and a curve traced by the end of the arm h. For calibrating the scale plate, the spring c together with the attached arms are taken out and placed in a similar instrument in which the tube is fitted with a micrometer screw instead of the part a.