Abstract This invention relates to a fluid pressure alarm for use primarily on vehicle tires including a self-contained powered radio transmitter in a cylindrical housing threaded on the inflation stem of the vehicle tire, the housing having means maintaining pressure communication between the interior of the tire and that of the housing, and a pressure responsive switch device biased by control pressure in a control pressure compartment of the housing and movable to energize the transmitter upon a predetermined pressure differential between that of the control compartment and that of the vehicle tire, the radio signal to be picked up by a receiver in the cab of the vehicle. it can be used as a pressure differential alarm on other pressurized gas or liquid environments.
A tire pressure alarm for use on the valved inflation stem of a vehicle tire, wherein the improvement comprises: an elongated housing having means for securing it on a vehicle tire inflation stem, a radio transmitter and a circuit therefor including a battery in said housing, a sealed control chamber in said housing having pressurized atmospheric air therein to substantially match the temperature response characteristics of the air in the vehicle tire, said control chamber including means adjustable to selectively preset the pressure of the air therein to the optimum pressure in the vehicle tire, and a circuit maker in the housing in said transmitter circuit and including means responsive to the pressures in said control chamber in the vehicle tire operable to close the transmitter circuit responsive to positive and negative air pressure differentials in the vehicle tire.
Claim 2
Dependent Claim
139 words
A tire pressure alarm for use on the valved inflation stem of a vehicle tire, wherein the improvement comprises: an elongated housing having means for securing it on a vehicle tire inflation stem, a radio transmitter and a circuit therefor including a battery in said housing, a sealed control chamber in said housing having pressurized atmospheric air therein to substantially match the temperature response characteristics of the air in the vehicle tire, said control chamber including means adjustable to selectively preset the pressure of the air therein to the optimum pressure in the vehicle tire, and a circuit maker in the housing in said transmitter circuit and including means responsive to the pressures in said control chamber in the vehicle tire operable to close the transmitter circuit responsive to positive and negative air pressure differentials in the vehicle tire.