GB745050A - Improvements in or relating to motion responsive devices such as accelerometers - Google Patents

Abstract

745,050. Electric accelerometer. STATHAM LABORATORIES, Inc. July 8, 1952 [Aug. 13, 1951], No. 17197/52. Class 40(1) [Also in Group XIX] A motion responsive device adapted for use as a vibrometer or an accelerometer comprises a liquid chamber adapted to be displaced in space, a liquid passageway in said chamber filled with a liquid inertial mass, said chamber being movable with respect to said liquid chamber inertial mass on displacement of said chamber in space to cause a motion of said liquid inertial mass entirely within said passageway and relative to the walls of said chamber, and means including a member positioned within said passageway responsive to said relative motion of said liquid inertial mass and said walls for measuring the magnitude of the relative displacement of said mass and said walls. For determining angular acceleration the device comprises a case 1, Figs. 1 and 2, having a centre core 3 and a top cover 4 defining a channel or passageway 2 of square cross-section. A barrier wall 6 having a circular orifice 7, Figs. 4 and 5, extends across the channel 2 into a recess 4a in the-core 3. A paddle 12 normally located in the orifice 7 is carried by the armature 11 of a known form of electric wire strain gauge comprising a frame 5 mounted on the wall 6 and carrying blocks 9, 10a, Fig. 6, for clamping one end of a spring 10, the other end of which is clamped between the armature 11 and a balance arm 15 to which a weight 16, Figs. 4 and 5, is movably attached. Strain wires 19 are stretched between pins 20 on the frame 8, armature 11 and balance arm 15 as shown. The case 1 contains a temperature compensating diaphragm 23. Any displacement of the liquid through the orifice 7 due to angular acceleration of the casing will cause displacement of the paddle 12 which will be measured by the-strain wire gauge suitably calibrated. In another embodiment for indicating linear acceleration the device comprises a cylinder 26a, Fig. 7, having end walls 28, 37 provided with vents 29, 38 respectively. The liquid is located between diaphragms held by gaskets 30. The paddle 43 is located in an orifice 32 in a barrier wall 31.