Tire pressure warning device

• US 4,737,760 A
• Filed: 12/06/1984
• Issued: 04/12/1988
• Est. Priority Date: 12/06/1984
• Status: Expired due to Fees

• Current Assignee: Chung-Siung Huang, Hsien-Ching Kuo
• Original Assignee: Chung-Siung Huang, Hsien-Ching Kuo
• Inventors: Kuo, Hsien-Ching, Huang, Chung-Siung
• Primary Examiner(s): Rowland, James L.
• Assistant Examiner(s): Mullen, Jr., Thomas J.
• Application Number:
  US06/678,739
• Time in Patent Office: 1,223 Days
• Field of Search: 340/58, 340/539, 340/572, 116/34 R, 73/146.8, 267/153, 137/227
• 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 23/0496 Valve stem attachments positioned outside of the tyre chamber
• CPC Class Codes: Y10T 137/3662 With gauge or indicator

Abstract

A tire pressure warning device is disclosed which comprises a body adapted to be threaded into the valve stem of the tire, a pressure sensing valve in the body and an elastomeric compression spring acting on the sensing valve to open it when the pressure in the tire is below a predetermined value. In one embodiment an alarm in the body is adapted to produce an audible signal in response to air flow through the sensing valve. In another embodiment the body includes a distendable diaphragm as a pressure sensor and an elastomeric compression spring for closing a switch when the air pressure is below a predetermined value. A radio transmitter in the body transmits a warning signal when the switch is closed. A monitor detects a transmitted audio or radio signal and compares it with a stored reference signal and produces an output signal only when the transmitted signal corresponds to the stored signal.

Claims

1. In a tire pressure warning device of the type comprising:

a body adapted to be threaded onto the filler valve stem of a tire and to open the tire valve therein and admit pressurized air from the tire to an inlet passage in said body,

a pressure sensing valve in fluid communication with said inlet passage, the pressurized air therein tending to close said sensing valve,

actuating means acting on the sensing valve to open it when the pressure of the pressurized air is below a predetermined value whereby air from the tire is allowed to flow through the sensing valve to an outlet passage in said body,

and alarm means in fluid communication with the outlet passage and adapted to produce an alarm signal in response to flow of air through the sensing valve,

the improvement wherein,

said actuating means comprises a silicone rubber compression spring.

2. A tire pressure warning device comprising:

a body adapted to be threaded onto the filler valve stem of a tire and to open the tire valve therein and admit pressurized air from the tire to an inlet passage in said body,

a pressure sensor including a distendable diaphragm in fluid communication with said inlet passage,

switching means and a switch actuator,

said switch actuator comprising a silicone rubber compression spring for closing the switching means when the pressure of the pressurized air is below a predetermined value,

a radio transmitter and a battery in said body,

said switching means being adapted to connect the battery to the transmitter for transmitting a warning signal.