APPARATUS FOR MEASURING TIRE PRESSURES

• US 3,596,509 A
• Filed: 08/18/1969
• Issued: 08/03/1971
• Est. Priority Date: 03/26/1966
• Status: Expired due to Term

• Current Assignee: Raffaelli Giulio
• Original Assignee: Raffaelli Giulio
• Inventors: RAFFAELLI GIULIO
• Application Number:
  US04/850,992
• Time in Patent Office: 715 Days
• US Class Current: 73/146.3
• CPC Class Codes: G01L 17/00 Devices or apparatus for measuring tyre pressure or the pressure in other inflated bodies
• CPC Class Codes: Y10T 137/3662 With gauge or indicator
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm

Abstract

A pressure gauge for communication with the air in a tire including a graduated circular scale rotatable with respect to a pointer in response to the pressure in the tire. The pointer is operatively connected to a galvanometer controlled by a circuit having two thermistors responsive to the temperatures of the air in the tire and the ambient air respectively.

Claims

1. An apparatus for measuring the inflation pressure in tires corrected for temperature variations to ambient temperature comprising:

support means;

a graduated scale rotatably carried by said support means;

driving means operatively connected to said scale and to said tire for rotating said scale in response to the actual inflation pressure in said tire;

indicator means carried by said support means and overlying said scale to indicate the reading on said scale; and

galvanometric means including means operatively connected to said indicator means and to said tire for shifting said indicator means with respect to said scale to cause said indicator means to indicate a reading on said scale corresponding to the inflation pressure the tire would have had if the tire were at ambient temperature.

2. Apparatus as set forth in claim 1 further including brake means for selectively locking the position of said indicator means a predetermined period of time after said driving means has rotated said scale.

3. Apparatus as set forth in claim 1 wherein said driving means includes mechanism for causing said scale to be rotated logarithmically in response to the inflation pressure in the tire.

4. Apparatus as set forth in claim 1 wherein said galvanometric means includes a pointer, a galvanometer, a first pickup responsive to the ambient air temperature operatively connected to said galvanometer, and a second pickup responsive to the air in the tire operatively connected to said galvanometer, said galvanometer constructed and arranged to combine the outputs differentially from said pickups and shift said pointer.

5. Apparatus as set forth in claim 2 wherein said brake means includes an electromagnetic brake, a timer, and a switch electrically connected in series, said switch activated by said driving means as said driving means shifts said scale and said timer actuating said brake a predetermined period of time after said switch is activated.

6. Apparatus as set forth in claim 4 wherein said galvanometer defines an air gap shaped so as to compensate for the deviations in the displacement of said pointer.