Distance measuring arrangements
First Claim
1. A distance measuring arrangement including an accelerometer transducer having an inertial mass, switching means arranged to be operated by the inertial mass, and an electromagnetic coil energizable by the switching means to produce a constant force acting on the inertial mass such that the switching means is opened and closed in a repetitive cycle, the proportion of each cycle for which the switching means causes the coil to be energised being dependent upon the sense and magnitude of an applied acceleration force, said arrangement also including signal means operable to provide in each cycle a signal representing said proportion of each cycle and integration means operable to integrate the signals with respect to time for a plurality of cycles to provide an indication of the distance travelled by the measuring arrangement.
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Accused Products
Abstract
A distance measuring arrangement has an accelerometer transducer of the force balance type in which a switch closed by the action of an acceleration force causes a constant current to flow in a coil to oppose the force and open the switch. The switch opens and closes in a repetitive cycle at the resonant frequency of the system, the closed switch gating clock pulses to integration means. The transducer may take two forms. In the first the proportion of time that the switch is closed in each cycle is proportional to the acceleration value. Distance measurement comprises counting the clock pulses to effect a first stage of integration and summating the counter totals every 1000 clock pulses to give a distance travelled signal. In the second, the proportion of time that the switch is closed in each cycle is proportional to the square root of the acceleration value and distance measuring comprises counting the clock pulses to give a signal proportional to the square root of distance travelled. In both cases this signal may be compared with a stored predetermined value to effect a control function.
7 Citations
11 Claims
- 1. A distance measuring arrangement including an accelerometer transducer having an inertial mass, switching means arranged to be operated by the inertial mass, and an electromagnetic coil energizable by the switching means to produce a constant force acting on the inertial mass such that the switching means is opened and closed in a repetitive cycle, the proportion of each cycle for which the switching means causes the coil to be energised being dependent upon the sense and magnitude of an applied acceleration force, said arrangement also including signal means operable to provide in each cycle a signal representing said proportion of each cycle and integration means operable to integrate the signals with respect to time for a plurality of cycles to provide an indication of the distance travelled by the measuring arrangement.
Specification