A tire puncture detecting device having a pressure chamber defined by a flexible diaphragm and held in communication with the interior of the tire, an atmospheric chamber communicating with the atmosphere, and a spring plate member disposed in the pressure chamber and supporting on the front face thereof a magnet and on the rear face thereof a central portion of the flexible diaphragm. The spring plate member is normally maintained in a retracted position under the air pressure in the pressure chamber against the bias of a resilient member disposed rearwardly of the spring plate member. When a reduction in the air pressure in the pressure chamber exceeds a predetermined degree, the spring plate member buckles so as to quickly project forwardly under the force of the resilient member. In this manner, the magnet supported on the spring plate member is moved closer to an alarm circuit switch located in front of the device and energizable by magnetic force, thereby actuating the switch. Puncturing of the tire is thus detected rapidly and reliably.
A pressure gauge for a pneumatic tire includes a casing, a pressure responsive signal-generating device disposed in the casing, an electric power source connected electrically to the signal-generating device, and a switch assembly connected electrically to the electric power source. The switch assembly includes a normally open reed switch, a magnet member and a magnet support. The reed switch is electrically connected to the electric power source. The magnet member is disposed movably in the casing to produce a magnetic field for activating the reed switch to an ON position, and is movable toward the reed switch via a centrifugal force produced upon rotation of the pneumatic tire. The magnet support is disposed adjacent to the reed switch to movably hold the magnet member, and has a biasing unit to provide a biasing action to move the magnet member away from the reed switch when the centrifugal force is absent.
A device and method for signaling differential pressure change occurring during leak testing of an evaporative emission control space in a motor vehicle fuel system. A casing has sensing ports one of which is communicated to a reference pressure, such as atmospheric pressure, and another of which is communicated to sense pressure in the evaporative emission control space. As difference between the reference pressure and the pressure in the control space changes, the net magnetic flux acting on a magnetoresistive sensor changes. The sensor is electrically connected to the vehicle electrical system for signaling the differential pressure. The device may be used for both positive and negative pressure leak testing.
This invention relates to the dispensing of liquids by means of a fluid dispensing apparatus (10) having one or more of a leakage detection means (94), a latching solenoid (84), and a fluid flow meter (20). The invention also provides each of the leakage detection means, the latching solenoid, then fluid flow meter, a fluid dispensing installation, and a method of dispensing fluid. In some embodiments, the fluid dispensing apparatus is a pre-payment water dispensing meter.
A device and method for signaling differential pressure change occurring during leak testing of an evaporative emission control space in a motor vehicle fuel system. A casing has sensing ports one of which is communicated to a reference pressure, such as atmospheric pressure, and another of which is communicated to sense pressure in the evaporative emission control space. As difference between the reference pressure and the pressure in the control space changes, the net magnetic flux acting on a magnetoresistive sensor changes. The sensor is electrically connected to the vehicle electrical system for signaling the differential pressure. The device may be used for both positive and negative pressure leak testing.
