Vehicle-tire-air-pressure-sensing-and-indicating device

• US 3,978,448 A
• Filed: 06/09/1975
• Issued: 08/31/1976
• Est. Priority Date: 06/09/1975
• Status: Expired due to Term

• Current Assignee: Schrader Automotive Incorporated
• Original Assignee: The Scovill Manufacturing Co. (Morito Company Limited)
• Inventors: Vago, Otto Zoltan
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/585,088
• Time in Patent Office: 449 Days
• Field of Search: 340/58, 200/61.22, 200/61.25
• US Class Current: 340/445
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0425 Means comprising permanent magnets, e.g. Hall-effect or Reed-switches

Abstract

In a vehicle tire pressure indicator system, a reed switch mounted on the vehicle frame adjacent a wheel is connected to indicator means in the vehicle. An elongage tubular housing of generally cylindrical outer configuration is disposed on the wheel lengthwise parallel to the axis of the wheel. One end of the housing, the outer end, is attached to the tire valve while the other end carries a covered bellows on the end of which is a magnet. The housing is situated to be adjacent the reed switch each time the wheel rotates. Tire pressure is communicated to the chamber surrounding the bellows inside the cover so that when tire pressure is high, the bellows shrinks and draws the magnet away from the reed switch, not influencing it. When tire pressure drops, the bellows extends, moving the magnet toward the switch, triggering the indicator means. The bellows is sealed by having its single bore plugged with a ball member. The bellows contains a stop limiting its collapsing movement. Valve means are provided in the outer end of the housing to shut off the communication means with the tire when the communications means is removed from the housing so that the system may be checked without losing tire pressure.

Claims

1. In a vehicle-tire-air-pressure-sensing-and-indicating device having magnetic-field sensitive switch means mounted on the vehicle adjacent the wheel connected through electrical means to indicating means within the vehicle, magnet means, mounting means on the wheel assembly mounting the magnet means for movement toward and away from the switch means in directions parallel to the axis of the wheel, the mounting means comprising a bellows having one end fixedly supported on the wheel assembly, the other end carrying the magnet means, and housing means surrounding the bellows and connecting means connecting the housing means to the tire;

the improvement wherein the bellows has a central bore at one end closed by a ball member to seal the bellows and the bellows is formed with an internal axially disposed elongate stop means limiting the collapse of the bellows, the housing means comprises an elongate, generally cylindrical tubular element disposed in a circular opening in the wheel structure and lying in a disposition parallel to the axis of the wheel and the connecting means includes tube means connected to the outer portion of the housing means and extending to the usual fill valve fitting of the tire on the wheel.

2. A vehicle-tire-air-pressure-sensing-and-indicating device as claimed in claim 1 wherein the bellows includes internal stop means extending in a direction longitudinal of the bellows to prevent collapse of the bellows beyond a certain length when the pressure in the tire is high.

3. A vehicle-tire-air-pressure-sensing-and-indicating device as claimed in claim 2 wherein the stop means extends from the magnet end of the bellows toward the stationary end.

4. A vehicle-tire-air-pressure-sensing-and-indicating device as claimed in claim 1 wherein the outer end of the housing is threaded and the tube means is connected to the threaded end of the housing by an adapter having a valve core biased toward open disposition with an outwardly-facing operating pin, the adapter being inserted into the threaded end, threaded thimble means on the threaded end holding the adapter projecting into the threaded end, and stationary depresser means in the housing depressing the core pin to open the valve when the adapter is so projected.

5. A vehicle-tire-air-pressure-sensing-and-indicating device as claimed in claim 1 wherein the bellows is sealed.

6. In a vehicle-tire-air-pressure-sensing-and-indicating device having magnetic-field sensitive switch means mounted on the vehicle adjacent the wheel connected through electrical means to indicating means within the vehicle, magnet means, mounting means on the wheel assembly mounting the magnet means for movement toward and away from the switch means in directions parallel to the axis of the wheel, the mounting means comprising a bellows having one end fixedly supported on the wheel assembly, the other end carrying the magnet, the bellows containing a gas at substantially uniform pressure at all times, and having tubular housing means surrounding the bellows and connecting means connecting the housing means to the tire;

the improvement wherein the housing means includes an elongate generally cylindrical tubular element enclosing and coaxial with the bellows and mounted on the wheel and extending lengthwise in a direction parallel to the axis of the wheel, the bellows being sealed and containing an axially disposed elongate stop means to limit the collapsing movement of the bellows, the connecting means including tube means connected to the outer end of the housing means and extending to the usual fill valve fitting of the tire on the wheel, and valve means in the connecting means at the housing means adapted to close automatically the connecting means when the connecting means is disconnected from the housing means as in testing the device.

7. A device as claimed in claim 6 wherein the valve means comprises a spring-pressed poppet-type valve biased toward closed disposition disposed in the connecting means and normally held open by means on the housing when the connecting means is connected to the housing means.

8. A device as claimed in claim 6 wherein the housing is disposed at a radius on the wheel equal to the radius on the wheel of the conventional wheel holding studs.