Abstract A rotary accelerometer using a piezoxide (prepolarized ceramic piezoelectric element). A shaft drives a rotating mass in the form of a cylindrical sleeve through a resilient connection in one embodiment. During angular deceleration, the rotating mass tends to lead because of inertia and the resulting force is applied to a cam device which converts that force into a compressive stress applied to the piezoxide to generate a voltage analog of deceleration. In another embodiment a block mass is attached to a piezoxide block directly, so that inertial forces during deceleration are directly applied to the piezoxide. The combination is then mounted so as to respond to tangential forces about a decelerating shaft.
The invention set forth in claim 1 in which said cam means comprises a thin walled cylindrical cage having a plurality of slots running at an angle with respect to shaft parallels, one end face of said cylindrical cage being firmly and coaxially connected to said shaft and the second end face being positioned substantially against one face of said transducer; and means including said resilient connection are included, whereby said second end face tends to extend axially in response to twisting of said cage to apply said compressive foRce when said mass tends to lead said shaft.
Claim 2
Independent Claim
90 words
A device for generating a signal which is the analog of angular acceleration comprising: a rotatable shaft, the angular acceleration of which is to be measured; a stationary piezoelectric transducer for generating an electrical signal which is a function of the compressive force applied to the transducer; and an inert mass coupled to the shaft for rotation therewith by a torque transmitting coupling, the coupling having means for applying a force to the transducer which is proportional to the torque transmitted and independent of the angular velocity of the shaft.
Claim 3
Dependent Claim
68 words
A device for generating a signal which is the analog of angular acceleration as defined in claim 3, wherein the coupling is a torsional member, the axial length of which varies as a function of the torque transmitted and the end of the torsional member abuts against the transducer whereby an electrical signal will be generated in the transducer in proportion to the torque transmitted through the coupling.