Pressure responsive sensing device

• US 4,201,081 A
• Filed: 07/17/1978
• Issued: 05/06/1980
• Est. Priority Date: 07/17/1978
• Status: Expired due to Term

• Current Assignee: Alamo Group Incorporated
• Original Assignee: M & W Gear Company
• Inventors: Bonomo, Melvin E.
• Primary Examiner(s): Yasich, Daniel M.
• Application Number:
  US05/925,046
• Time in Patent Office: 659 Days
• Field of Search: 73/141 A, 73/141 R, 73/745, 73/746, 73/726, 73/727, 73/728, 73/820, 177/208
• US Class Current: 73/862.581
• CPC Class Codes: G01L 1/02 by hydraulic or pneumatic means
• CPC Class Codes: G01L 9/0041 Transmitting or indicating the displacement of flexible diaphragms

Abstract

A pressure responsive sensing device includes a housing defining a chamber. The chamber is filled with a non-compressible fluid and is closed at one end by a diaphragm. The diaphragm is retained in position by a cover plate. A stem connected to the outside of the cover plate projects through a bearing passage and has an outer end exposed to receive a force. A force on the end of the stem is transmitted via the plate and diaphragm against the fluid in the chamber. The pressure in the chamber, in turn, is transmitted ,o an electronic transducer sensing device through a constricted passage in the wall of the housing.

Claims

1. An improved pressure sensitive transducer measurement device comprising, in combination:

a housing, said housing defining a chamber open at one end having a tubular housing wall;

a generally non-compressible fluid within the chamber;

a constricted passage through the housing wall to the chamber for receipt of said fluid;

an electronic transducer device attached to the housing in communication with the constricted passage and on the outside of the chamber;

a cover plate over the open end of the housing and attached to enclose the chamber;

a diaphragm member retained between the cover plate and the housing and defining a generally planar interior surface of the chamber at the open end;

a plate member retained by the cover plate in opposed relation with the diaphragm member on the side of the diaphragm member opposite the interior of the chamber;

said cover plate having a bearing passage defining a bearing surface; and

a stem connected to the plate member and having an anvil attached to an end, said end generally frictionlessly projecting through the bearing passage in the cover plate for receipt of a force, said stem transmitting said force through the plate member against the diaphragm and to the noncompressible fluid within the chamber, so that the pressure in the fluid is equal to the force divided by the area of the interior surface of the diaphragm member, said pressure being transmitted through the constricted passage to the electronic transducer device, the diameter of the constricted passage and the ratio of the area of said plate member to the anvil so dimensioned to thereby avoid hysteresis in the output of said device, the ratio of the length of the bearing surface to the diameter of the stem being greater than 2.0 to 1.

2. The device of claim 1 wherein the ratio of the area of the surface of said plate member against the diaphragm to the exposed area of said anvil is substantially 10 to 1.

3. The device of claim 1 wherein the ratio of the length of said bearing surface to the diameter of said stem is substantially 2.5 to 1.