Valve mounted pneumatic tire pressure sensing switch

• US 3,908,105 A
• Filed: 05/20/1974
• Issued: 09/23/1975
• Est. Priority Date: 05/20/1974
• Status: Expired due to Term

• Current Assignee: Howard M. Schuler
• Original Assignee: Howard M. Schuler
• Inventors: Schuler, Howard M.
• Primary Examiner(s): Scott, James R.
• Application Number:
  US05/471,506
• Time in Patent Office: 491 Days
• Field of Search: 200/61.22-61.25,83R,83B,83N,83S 116/34 340/58 73/146.5,146.8,49
• US Class Current: 200/61.25
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: H01H 35/24 Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow wherein the change of pressure is caused by change of temperature H01H37/36

Abstract

A pressure sensing switch for use in a low pressure monitoring and warning system for a pneumatic tire comprising a housing and an improved dimpling metal dome therein, to provide a normally open pressure-sensitive switch, adapted for mounting as an extension to the valve stem of a pneumatic tire. The dimpling metal dome is mounted within the housing with its convex face in communication with the pressure in the pneumatic tire such that the dimpling of the dome will open the electrical contact whenever the tire pressure is above a predetermined norm. Means are provided in the side of the housing in electrical contact with the base and convex face of the dome in order to establish the switch circuit, and to provide for adjustment of the prestress force on the dome. Screw terminals are also provided for the external connection of electrical connecting wires to the remainder of the monitoring and warning system.

Claims

1. A tire pressure sensing switch device for mounting on the valve stem of a pneumatic tire comprising a. a body having axially aligned, longitudinally spaced apart threaded apertures, respectively, for mounting on a tire valve stem and for receiving a valve core, b. an orifice extending through said body transversely of and between said apertures, c. a plug of insulating material received in one end portion of said orifice, d. an electrical terminal mounted in said plug and insulated thereby from said body, e. an annular shoulder at the other end of said orifice, f. a pressure chamber between said plug and said shoulder and communicating with said apertures, g. a thin metal, dimpling-type diaphragm traversing said chamber and secured against said shoulder, h. a contact element for electrically connecting said terminal and the flexing crest of said diaphragm in one position of the latter, and i. means for making constant electrical connection with said diaphragm to complete an electrical circuit through said terminal and said diaphragm crest in said one position thereof, said diaphragm crest being adapted to respond to changed pressure condition in said pressure chamber to separate said crest from said contact element and thereby break said circuit, j. said body being substantially symmetrical and balanced about the axis of said aligned apertures to minimize bending stresses applied to the supporting tire valve stem in operation.

2. A tire pressure sensing switch device as described in claim 1 in which said diaphragm crest is positioned to flex in the direction axially of said orifice, said contact element being threadedly mounted in said plug substantially coaxially with said diaphragm crest for adjustment of the diaphragm shape in said one position thereof.

3. A tire pressure sensing switch device as described in claim 1 in which said means for making constant electrical contact with said diaphragm comprises a closure in the end of said orifice opposite said plug, and further including a second terminal mounted in said closure and electrically connected to said diaphragm.