PULSE STRETCHER FOR A RECEIVER OF A PNEUMATIC TIRE LOW PRESSURE MONITORING AND WARNING SYSTEM

• US 3,796,990 A
• Filed: 09/15/1972
• Issued: 03/12/1974
• Est. Priority Date: 09/15/1972
• Status: Expired due to Term

• Current Assignee: Charles E. Hill
• Original Assignee: Charles E. Hill
• Inventors: Hill, Charles E.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/289,552
• Time in Patent Office: 543 Days
• Field of Search: 340/58,224 200/61.22,61.25,61.26
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0433 Radio signals

Abstract

An electrical apparatus or pulse stretcher is provided and a pneumatic tire low pressure monitoring and warning system using same wherein such apparatus increases the effective time duration of useable electrical signals supplied thereto to thereby activate an indicator associated therewith. The apparatus comprises an NPN transistor having base, collector, and emitter electrodes and a cooperating PNP transistor having base, collector, and emitter electrodes with the PNP transistor having its collector electrode connected directly to the indicator and to the base of the NPN transistor by a positive feedback loop, each useable signal being supplied to the base of the NPN transistor through a rectifying diode and stored in a capacitor connected functionally from base to ground. The signal operates to turn the PNP transistor ON and simultaneously supply a voltage through the collector electrode of the PNP transistor to activate the indicator whereby the transistors operate to increase the effective time duration of each useable signal supplied to the NPN transistor.

Claims

1. A pneumatic tire low pressure monitoring and warning system comprising, means sensing a low pressure condition in a pneumatic tire supported on an associated vehicle by a rotatable support, a transmitter carried by and being rotatable with said rotatable support with said transmitter being actuated by said sensing means and providing output signals at a radio frequency in response to said low pressure condition;

a receiving antenna attached at a fixed position on said vehicle adjacent said tire;

said antenna receiving useable ones of said output signals only during a portion of each complete rotation of said transmitter therepast;

a receiver;

means operatively connecting said receiving antenna to said receiver;

indicating means operatively connected to said receiver and being activated thereby; and

means in said receiver for increasing the effective time duration of said useable ones of said output signals, said increasing means assuring said indicating means is activated only in response to said low pressure condition and comprising, an NPN transistor having base, collector, and emitter electrodes, a cooperating PNP transistor having base, collector, and emitter electrodes, said PNP transistor having its collector electrode connected to said indicating means and a positive feedback circuit connecting said collector electrode of said PNP transistor to said base electrode of said NPN transistor, each useable signal being supplied to said base of said NPN transistor and operating to turn said PNP transistor ON and simultaneously supply a voltage through said collector electrode of said PNP transistor to activate said indicating means, each useable signal being increased in effective time duration due to hysteresis of said feedback circuit, time delay in reduction in potential of said base of said PNP transistor, and time delay introduced by said feedback circuit.

2. A system as set forth in claim 1 in which said indicating means is an indicator lamp.

3. A system as set forth in claim 1 in which said transmitter is a self-pulsed transmitter, and said indicating means is an indicator lamp.

4. A system as set forth in claim 3 in which said positive feedback circuit has a resistor provided therein.

5. A system as set forth in claim 4 and further comprising a second resistor operatively connected between said collector electrode of said PNP transistor and said base electrode of said PNP transistor.