Pneumatic pressure sensor device
First Claim
1. A pneumatic pressure sensor switch device for a pneumatic tire, comprising:
- means for mounting said device entirely in an inflation chamber of the tire, a sensor having two closed chambers filled with gas, a first chamber of said chambers being bordered by two flexible diaphragms in opposite walls thereof, a first diaphragm of said diaphragms separating said first chamber from and being exposed to the pressure in the inflation chamber of the tire, a second diaphragm of said diaphragms separating said closed chambers mutually and carrying an electrical contact point moving therewith and cooperating with a stationary contact point in the sensor, an electric circuit including said contact points, a transmitter to give radio signals to the outside when said circuit is closed, said first closed chamber between said two diaphragms being filled by gas under pressure above atmospheric pressure, so that movements of said first diaphragm are adapted to vary the pressure of the gas in said first chamber by which pressure variation the second diaphragm is moved, a second closed chamber being filled with a gas under pressure above atmospheric pressure said electrical contacts being open at higher outside pressures on said first diaphragm and closed by said second diaphragm at lower outside pressures on said first diaphragm.
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Accused Products
Abstract
A pneumatic pressure sensor switch device for giving a warning signal if a pneumatic vehicle tire has too low pressure has a gas-filled chamber, separated from the inflation space in the tire by a first flexible diaphragm, and having another, second flexible diaphragm as its opposite wall, which has electrical contact means cooperating with a stationary contact point in the sensor. If the tire pressure is not too low, the first diaphragm is moved by the tire pressure to compress the gas in the said gas-filled chamber, which gas moves the second diaphragm out of contact with the stationary contact point. If the tire pressure drops below a certain value, the second diaphragm closes an electric circuit with battery and transmitter, so that a signal is given to the outside. There may be a third diaphragm bordering another closed chamber and by an electric series-connection to said second diaphragm, avoiding that a signal is given at atmospheric outside pressure, so as not to lose energy during storage or absence of a tire on the wheel. There may be two or more such sensors giving a signal at different pressures and they may be embodied so as to give signals in the correct pressure range in tires having two different inflation pressures in view of different loads of the vehicle or adaptation to switching tires from front to back of the vehicle.
30 Citations
11 Claims
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1. A pneumatic pressure sensor switch device for a pneumatic tire, comprising:
- means for mounting said device entirely in an inflation chamber of the tire, a sensor having two closed chambers filled with gas, a first chamber of said chambers being bordered by two flexible diaphragms in opposite walls thereof, a first diaphragm of said diaphragms separating said first chamber from and being exposed to the pressure in the inflation chamber of the tire, a second diaphragm of said diaphragms separating said closed chambers mutually and carrying an electrical contact point moving therewith and cooperating with a stationary contact point in the sensor, an electric circuit including said contact points, a transmitter to give radio signals to the outside when said circuit is closed, said first closed chamber between said two diaphragms being filled by gas under pressure above atmospheric pressure, so that movements of said first diaphragm are adapted to vary the pressure of the gas in said first chamber by which pressure variation the second diaphragm is moved, a second closed chamber being filled with a gas under pressure above atmospheric pressure said electrical contacts being open at higher outside pressures on said first diaphragm and closed by said second diaphragm at lower outside pressures on said first diaphragm.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
Specification