GB565504A - Improvements in or relating to gauges for internal measurements - Google Patents

Abstract

565,504. Gauges. KAPELLA, Ltd., and COOKE, E. A. March 16, 1943, No. 4269. [Class 106 (ii)] A gauge for measuring internal diameters of gun barrels or other tubes comprises a body A carrying two relatively movable gauging elements F, F<4>, the relative movement of which controls an indicating or recording instrument, and two pairs of ligament springs A<1>, A<2> and A3, A<4> (not shown) by which the body A is supported from a guide member C<1> slidable along the tube to be gauged. The guide member, which may constitute the tool for boring the gun barrel, carries an adapter C to which are connected the springs A<3>, A<4> supporting an annulus B bearing the springs A<1>, A<2> connected to the body A, which is accordingly free to move with its axis parallel to itself. Mounted on ball bearings in the body is a hollow member D bearing three adjustable reaction points F<4> and F<6>, F<7> (not shown) and the feeler F which is spring-pressed inwards against a spring-pressed lever H<1>, pivoted at H<2>. The feeler F is adjusted initially by a wedge H controlled by a worm H<7>. Movement of the feeler and hence of the lever H<1> affects the reluctance of coils H<4>, leads from which pass through a tube C' to a meter and a potentiometer, Fig. 6 (not shown) affording a measure of the movement. The hollow member D is rotated through a small angle for successive measurements. The weight of the gauge body A is compensated by an adjustable spring A<5>. A follower member G<1> is normally locked up clear of the tube, but in gauging the bore of a rifled barrel, an end cap G is released and turned until the follower G<1> lies'on the base of one of the grooves and the feeler F lies on one of the crests. The end cap and follower are then locked in position, and the gauge is passed through the bore once for each groove. In the modification shown in Fig. 8, movement of the feeler S rocks a block R, pivotally secured to the frame by springs R3 at right angles, and the block displaces an armature axially to affect the reluctance of coils Q. In this case, the guide member C' embraces the gauge body. The reaction point S<1> may be adjusted through a block similar to R, Fig. 13 (not shown), and instead of the other two reaction points, a steadying plate V, Fig. 14, with suitably shaped ends V<1> may be employed.