Tire pressure warning devices
First Claim
1. A tire pressure warning device comprising the combination of a non-rotating assembly for mounting on a non-rotating part of a vehicle and including a pick-up, and a rotating assembly for mounting on a wheel of the vehicle so that it passes adjacent the non-rotating assembly, said rotating assembly including a single coil adapted to be energized by movement of the rotating assembly past the non-rotating assembly, a pressure actuated switch sensitive to tire pressure and arranged to close at normal tire pressure, and synchronizing switch means operable to permit release of the energy stored by said coil whilst said coil is adjacent said pick-up, said single coil, pressure actuated switch and synchronizing switch means being arranged in series, the arrangement being such that said release of energy is prevented if the pressure operated switch opens.
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Accused Products
Abstract
A vehicle tire pressure warning system includes a rotating assembly and a non-rotating assembly. The non-rotating assembly includes a magnet and a pick-up coil. The rotating assembly includes a series circuit comprising a coil, a magnetically operated switch and a pressure actuated switch which is closed when the tire pressure is adequate. The magnetic switch is closed periodically by the magnet and current is induced in the coil. When the magnetic switch re-opens the coil is coupled to the pick-up coil and the flux collapse in the coil causes a signal to be induced in the pick-up coil. The absence of such a signal indicates that the tire pressure is too low and is detected by a counter system for each wheel which counts the number of pulses from all the wheels between pulses from the associated wheel.
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Citations
12 Claims
- 1. A tire pressure warning device comprising the combination of a non-rotating assembly for mounting on a non-rotating part of a vehicle and including a pick-up, and a rotating assembly for mounting on a wheel of the vehicle so that it passes adjacent the non-rotating assembly, said rotating assembly including a single coil adapted to be energized by movement of the rotating assembly past the non-rotating assembly, a pressure actuated switch sensitive to tire pressure and arranged to close at normal tire pressure, and synchronizing switch means operable to permit release of the energy stored by said coil whilst said coil is adjacent said pick-up, said single coil, pressure actuated switch and synchronizing switch means being arranged in series, the arrangement being such that said release of energy is prevented if the pressure operated switch opens.
- 10. A vehicle pressure warning system including a plurality of tire pressure warning devices associated respectively with a plurality of wheels of the vehicle, each tire pressure warning device comprising the combination of a non-rotating assembly for mounting on a non-rotating part of a vehicle and including a pick-up, and a rotating assembly for mounting on a wheel of the vehicle so that it passes adjacent the non-rotating assembly, said rotating assembly including a single coil adapted to be energized by movement of the rotating assembly past the non-rotating assembly, a pressure actuated switch sensitive to tire pressure and arranged to close at normal tire pressure, and synchronizing switch means operable to permit release of the energy stored by said coil whilst said coil is adjacent said pick-up, said single coil, pressure actuated switch and synchronizing switch means being arranged in series, the arrangement being such that said release of energy is prevented if the pressure operated switch opens, a plurality of counters associated with the respective devices and adapted to acquire a count state, a logic circuit connecting the pick-up of the respective devices to the counters so that each counter is periodically reset by pulses produced by its associated device and counts pulses produced by all the other devices, warning means, and means sensitive to the count state of each counter to make operative said warning means if the count state of a counter exceeds a predetermined value.
Specification