Low mass pointer element for a pressure measuring mechanism
AssigneeWelch Allyn, Inc.
InventorsRaymond A. Lia, Robert L. Vivenzio, James M. Baxter, Michael Kehoskie
Life of this patent
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Abstract
A low-mass pointer element for a pressure measuring mechanism is made from a lightweight plastic paper material and includes a center hub having a through aperture which is sized to accommodate a rotatable shaft end of the pressure measuring mechanism. An indicating end of the pointer element is sloped downwardly toward a dial face relative to the center hub to prevent parallax along with a counterbalancing portion. The indicating end is inwardly tapered to a flattened distal end to provide equivalent stiffness, but with considerably less mass so as to significantly reduce stress loads on a corresponding movement mechanism.
Claims30
A pressure measuring mechanism comprising:
- an axially extending shaft member having a first end and a locking member disposed in proximity to said first end;
- a dial face disposed in relation to the first end of said axially extending shaft member;
- and
- a pointer element adapted for rotary movement with respect to said dial face, said pointer element comprising:
- a center hub having a recess for receiving the locking member of said axial shaft;
- an indicator portion extending from said center hub;
- and
- a counterbalance portion for counterbalancing said indicator portion, said counterbalance portion oppositely extending from said center hub, said indicator portion being inwardly tapered to a blade end, and in which said pointer element is formed from a lightweight material.
A movement mechanism for a measuring device, said movement mechanism comprising:
- an axially movable shaft member having opposing first and second ends;
- axial displacement means for moving the first end of said shaft member in an axial direction;
- a fixed support;
- at least one spring member coaxially positioned relative to said shaft member axis and helically wound about said axially movable shaft member, said helically wound spring member being attached at one end to an intermediate portion of said shaft member and attached at an opposite end to said fixed support, wherein said displacement means acts directly on said shaft member to cause it to translate in said axial direction, said helically wound spring member to flex, and said axially movable shaft member to rotate, said helically wound spring further supplying a restoring force to return said shaft member to an initial position when said axial displacement means stops moving the first end of said axially movable shaft member;
- a dial face having measuring indicia fitted around the first end of said axially movable shaft member;
- and;
- a low mass pointer element fitted onto the first end of said axially movable shaft member, said pointer element being capable of circumferential movement relative to the indicia of said dial face.
Dependencies are inferred from the claim text.