Low tire pressure warning system with mechanical latching

• US 3,977,355 A
• Filed: 11/12/1975
• Issued: 08/31/1976
• Est. Priority Date: 11/12/1975
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Schlanzky, Manfred P. H., Lorenz, Edwin A.
• Primary Examiner(s): Woodiel, Donald O.
• Application Number:
  US05/630,957
• Time in Patent Office: 293 Days
• Field of Search: 73/146.5, 116/34 R, 116/114 PV, 340/58
• US Class Current: 116/34.00R
• CPC Class Codes: B60C 23/007 having multiple wheels arranged side by side
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

An air switch senses abnormally low pressure in a tire and provides a pneumatic signal to an actuator which moves a magnet from a normal position to a warning position. An electrical detection system senses that the magnet is in a warning position and provides a low pressure warning signal to the vehicle operator. The actuator contains a mechanical latch to assure that the magnet remains in a warning position even if the pneumatic signal should cease. A reset feature allows the latch to be disengaged to return the actuating mechanism to normal condition when proper tire inflation pressure has been restored.

Claims

1. A low tire pressure warning system for providing and maintaining an indication of tire pressure decrease below a normal value comprising,

normally closed vlave means connected to a tire and having an inlet in communication with tire pressure, the valve having an outlet and means responsive to tire pressure for opening the valve to exhaust tire air under pressure through the outlet when tire pressure decreases below a normal value,

actuator means pneumatically connected to the outlet of said valve means including an actuator element biased to a normal position and responsive to the pressure of said tire air exhausted through the outlet for movement from the normal position to a warning position when tire pressure decreases below a normal value, and a latch mechanism responsive to movement of the actuator element to the said warning position for holding the actuator element in warning position irrespective of the continuance of the tire air pressure from the said valve outlet,

and means responsive to the actuator element in warning position to provide a low tire pressure indication.

2. A low tire pressure warning system for providing and maintaining an indication of tire pressure decrease below a normal value comprising,

normally closed valve means connected to a tire and having an inlet in communication with tire pressure, the valve having an outlet and means responsive to tire pressure for opening the valve to exhaust tire air under pressure through the outlet when tire pressure decreases below a normal value,

actuator means pneumatically connected to the outlet of said valve means including an actuator element biased to a normal position and responsive to the pressure of said tire air exhausted through the outlet for movement from the normal position to a warning position when tire pressure decreases below a normal value, the actuator element including elongated means connected for longitudinal linear movement upon movement of the actuator element and having an abutment portion, and a latch mechanism comprising a detent element mounted for movement transverse to the elongated means, biasing means for moving the detent element into engagement with the abutment portion of the elongated means when the actuator element is moved to warning position for holding the actuator element in warning position irrespective of the continuance of the tire air pressure from the valve outlet,

and means responsive to the actuator element in warning position to provide a low tire pressure indication.

3. A low tire pressure warning system for providing and maintaining an indication of tire pressure decrease below a normal value comprising,

normally closed valve means connected to a tire and having an inlet in communication with tire pressure, the valve having an outlet and means responsive to tire pressure for opening the valve to exhaust tire air under pressure through the outlet when tire pressure decreases below a normal value,

actuator means pneumatically connected to the outlet of said valve means including an actuator element biased to a normal position and responsive to the pressure of said tire air exhausted through the outlet for movement from the normal position to a warning position when tire pressure decreases below a normal value, the actuator element including elongated means connected for longitudinal linear movement upon movement of the actuator element and having an abutment portion, and a latch mechanism comprising a detent element mounted for movement transverse to the elongated means, the elongated means interfering with movement of the detent element to hold the detent element in normal position when the actuator element is in normal position, biasing means for moving the detent element into engagement with the abutment portion of the elongated means when the actuator element is moved to warning position for holding the actuator element in warning position irrespective of the continuance of the tire air pressure from the valve outlet, and manually operated reset means connected to the detent means for returning the detent means to normal position thereby allowing the actuator element to return to normal position,

and means responsive to the actuator element in warning position to provide a low tire pressure indication.