GB579206A - Improvements in or relating to extensometers or similar instruments - Google Patents

Abstract

579,206. Indicating ; gauges. HAMILTON, A. M. March 29,1944, No. 5779. [Classes 106 (ii) and 106 (iv)] An extensometer or similar instrument comprises a metal strip havirig points of flexure near its ends which are connected to the extensible or movable member, and an intermediate point of flexure, the strip being inflexible elsewhere and indicating means comprising a member or members rigidly connected to the inflexible part or parts of the strip so as to execute the angular movement thereof. The invention may be applied to weighing-apparatus and temperature measuring devices. In Figs. 1 and 2, a metal plate substantially in the form of an isosceles triangle divided over part of a median, is bent to form a bent strip 20 provided with triangular arms 21, 22 arranged at right angles to the strip. A notch 24 is cut out of the plate to facilitate bending. Lugs 28 at the ends of the strip are secured to the web of a bridge to be tested. Pins 26 on an indicating pointer 27 are inserted in perforations in elements 25 formed on or secured to the arms so that deformation of the bridge member results in movement of the pointer. In a modification, a stylus is mounted on the arm 22 and a record chart is mounted on the arm 21. In a further modification, transparent wings 21 carrying scales are adapted to move on either side of the wing 22. In a device which may be used as outside calipers, Figs. 10 and 11, the ends of the strip 20 are secured to brackets 46 adjustably mounted on channel members 47 riveted to a frame 49 with adjustable plates 51 which may be separated by applying pressure to the ends of the channel members. A device 54 limits inward movement of the ends.