Pulse stretcher for a receiver of a pneumatic tire low pressure monitoring and warning system

Claim 2

An electrical apparatus for providing a reliable indication when a repetitive series of effective output pulse signals of short time duration are supplied thereto as the result of a low pressure condition in a pneumatic tire of as associated vehicle, said effective pulses being separated by ineffective intervals of much greater time duration than the effective pulses, said electrical apparatus comprising a first electrical device which extends the time periods of said effective output pulses from said electrical apparatus indefinitely when activated by one of said short duration effective pulses; indicating means displaying an inadequate indication when the pulse signal of short time duration is used to control said indicating means directly; and a second electrical device associated with said indicating means for terminating the extended effective output pulses generated by said first electrical device after a preselected time interval and thereby generating effective control pulses of much longer time duration than the short time duration effective output pulses.

Claim 3

In a pneumatic tire low pressure monitoring and warning system having; means sensing a low pressure condition in a pneumatic tire supported on an associated vehicle by a rotatable support; a transmitter carried off center by said rotatable support and being rotatable therewith at a distance from the central axis of rotation, said transmitter being actuated by said sensing means and generating output signals at a radio frequency in response to said low pressure condition; a receiving antenna attached at a fixed position adjacent said tire within the near field of said transmitter, the coupling between said transmitter and said receiving antenna being subject to variations resulting from differences in distance, orientation and shielding between said transmitter and said receiving antenna; said receiving antenna receiving usable radio frequency signals only during a relatively small portion of each complete rotation of said transmitter therepast when the coupling is maximized; a receiver; and means operatively connecting said receiving antenna to said receiver; said transmitted radio frequency signal generating in said receiver a discontinuous control signal comprising a repetitive series of effective pulse signals of short duration, said effective pulses being separated by ineffective intervals of much greater time duration than said effective pulses; the improvement comprising a first electrical device which extends the time periods of the effective output pulses indefinitely when activated by one of said short duration effective pulses; indicating means providing an inadequate indication when said pulse signal of short time duration is used to control said indicating means directly; and a second electrical device associated with said indicating means for terminating said extended effective output pulses generated by said first electrical device after a preselected time interval and thereby generating effective control pulses of much longer time duration than the short time duration effective pulses wherein the long duration control pulses control said indicating means to thereby define the identifiable indication by a repeated activation of said firSt electrical device.

Claim 4

In a pneumatic tire low pressure monitoring and warning system having; means sensing a low pressure condition in a pneumatic tire supported on an associated vehicle by a rotatable support; a transmitter carried off center by said rotatable support and being rotatable therewith at a distance from the central axis of rotation, said transmitter being actuated by said sensing means and generating output signals at a radio frequency in response to said low pressure condition; a receiving antenna attached at a fixed position adjacent said tire within the near field of said transmitter, the coupling between said transmitter and said receiving antenna being subject to variations resulting from differences in distance, orientation and shielding between said transmitter and said receiving antenna; said receiving antenna receiving usable radio frequency signals only during a relatively small portion of each complete rotation of said transmitter therepast when the coupling is maximized; a receiver; and means operatively connecting said receiving antenna to said receiver; said transmitted radio frequency signal generating in said receiver a discontinuous control signal comprising a repetitive series of effective pulse signals of short duration, said effective pulses being separated by ineffective intervals of much greater time duration than said effective pulses; the improvement comprising a first electrical device which extends the time periods of the effective output pulses indefinitely when activated by one of said short duration effective pulses; indicating means providing an inadequate indication when said pulse signal of short time duration is used to control said indicating means directly; and a second electrical device associated with said indicating means for terminating said extended effective output pulses generated by said first electrical device after a preselected time interval and thereby generating effective control pulses of much longer time duration than the short time duration effective pulses wherein the long duration control pulses control said indicating means to thereby define the identifiable indication by a repeated activation of said firSt electrical device.

Claim 5

An apparatus as set forth in claim 1 in which said first electrical device is an SCR.

Claim 6

An apparatus as set forth in claim 3 in which said indicating means is a filament lamp.

Claim 7

An apparatus as set forth in claim 4 in which said second electrical device is a bimetallic strip, and in which said indicating means is a flasher filament lamp wherein said second electrical device is combined with said indicating means.

Claim 8

In a pneumatic tire low pressure monitoring and warning system as set forth in claim 2 the further improvement wherein said first electrical device is an SCR.

Claim 9

In a pneumatic tire low pressure monitoring and warning system as set forth in claim 6 the further improvement wherein said indicating means is a filament lamp.

Claim 10

In a pneumatic tire low pressure monitoring and warning system as set forth in claim 7 the further improvement wherein said second electrical device is a bimetal strip and in which said indicating means is a flasher filament lamp wherein said second electrical device is combined with said indicating means.

Claim 11

In a pneumatic tire low pressure monitoring and warning system as set forth in claim 8 the further improvement comprising an RC filter and a current limiting resistor connected to said SCR.

Claim 12

In a pneumatic tire low pressure monitoring and warning system as set forth in claim 6 in which each of said transmitters comprises a self-pulsed oscillator.