INTERROGATING TIRE PRESSURE INDICATOR

• US 3,723,966 A
• Filed: 09/14/1970
• Issued: 03/27/1973
• Est. Priority Date: 09/14/1970
• Status: Expired due to Term

• Current Assignee: Rolf K. Mueller, William G. Wolber
• Original Assignee: Rolf K. Mueller, William G. Wolber
• Inventors: Mueller, Rolf K., Wolber, William G.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/071,706
• Time in Patent Office: 925 Days
• Field of Search: 340/58 200/61.22,61.25 325/117,113,8
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: G06K 19/07764 the adhering arrangement making the record carrier attachable to a tire tire temperature or pressur control arrangements, see B60C23/00

Abstract

A tire pressure indicating arrangement in which a passive transponding element is used as the tire pressure condition responsive sensor at each tire and an active transmitter is used to interrogate either successively or simultaneously each transponder, each of which is in turn adapted to transpond back to a receiver in response to the transmitter signal in the event tire pressure declines to an unsafe level. The receiver signal is then used to activate an alarm or indicating device.

Claims

1. A vehicle wheel and tire assembly condition indicating arrangement comprising:

transmitter means for transmitting a signal of radio frequency radiation;

transponding means carried by said wheel and tire assembly and adapted to transpond a signal of radio frequency radiation in response to said transmitter means radiated signal;

sensor means causing a variation in the tRansponding activity of said transponding means in response to variations in said wheel and tire assembly condition;

indicator means carried by said vehicle providing indicator signals in response to said transponding means radiated signal indicating a variation in said wheel and tire assembly condition.

2. The arrangement of claim 1 wherein said sensor means includes pressure sensing means causing a variation in said transponding means activity in response to a change in tire pressure.

3. The arrangement of claim 2 wherein said sensing means includes means causing said transponding means to be inoperative above a predetermined pressure level in said tire.

4. The arrangement of claim 3 wherein said transponding means includes an oscillatory circuit and said sensor means includes means interrupting said circuit whenever said tire pressure exceeds a predetermined pressure level.

5. The arrangement of claim 1 wherein said transponding means includes a variable frequency oscillatory circuit and wherein said sensor means includes means varying the frequency of said oscillatory circuit in response to changes in said wheel and tire assembly condition.

6. The arrangement of claim 5 wherein said sensor means varies the capacitance of said circuit as a function of tire pressure.

7. The arrangement of claim 5 wherein said sensor means varies the inductance of said circuit as a function of tire pressure.

8. The indicator arrangement of claim 1 further including a plurality of said transponding means each carried by a respective wheel and tire assembly and wherein each of said transponding means signals is of a different frequency, and wherein said transmitter means transmits signals of a range of frequencies including said frequencies of each of said transponding means.