Load cell
AssigneeHoneywell International Inc.
InventorRichard Wade
Life of this patent
Estimating the term…
Abstract
The load cell for measuring a force in both push and pull includes a body assembly having a body element defining a measurement chamber with a closed end and an opposite open end, a protruding member positioned within the measurement chamber and extending from the closed end toward the open end. The load cell also includes a base assembly secured at the open end of the body element, including a base element; and a sense die attached to the base element and aligned with the protruding member, where a top surface of the sense die supports a Wheatstone bridge circuit configured to generate a signal based on a force exerted by the protruding member on the sense die. The body element, the protruding member and the base element are integrally formed from a common material which has a CTE close to the CTE of the sense die.
Claims20
A load cell, comprising:
- a body assembly comprising a body element defining a measurement chamber having a closed end and an open end, wherein the body element comprises a protruding member positioned within the measurement chamber and extending from the closed end toward the open end;
- and
- a base assembly secured at the open end of the body element, wherein the base assembly comprises a sense die aligned with the protruding member, wherein a top surface of the sense die supports a circuit configured to generate a signal based at least in part on a force exerted by the protruding member on the sense die,
- wherein the protruding member causes a stress in the sense die and the stress in the sense die correlates to a force,
- wherein the load cell is prestressed by the protruding member in a zero force condition associated with the load cell, and
- wherein the load cell is electronically calibrated to correlate a decrease in the stress within the sense die to a pull force exerted on the load cell, and an increase in the stress within the sense die to a push force exerted on the load cell.
A method of measuring a force, comprising:
- monitoring stress of a sense die of a load cell caused by force exerted by a protruding member on the sense die, the load cell comprising a body assembly and a base assembly, the body assembly comprising a body element defining a measurement chamber having a closed end and an open end, the body element comprising the protruding member and extending from the closed end toward the open end, the base assembly secured at the open end of the body element, and the base assembly comprising the sense die, wherein a top surface of the sense die supports a circuit configured to generate a signal based at least in part on a force exerted by the protruding member on the sense die, wherein the protruding member causes a stress in the sense die and the stress in the sense die correlates to a force, and wherein the load cell is prestressed by the protruding member in a zero force condition associated with the load cell;
- correlating the stress to a push force or a pull force applied to the body element relative to the base assembly;
- and
- calibrating the load cell to correlate a decrease in the stress within the sense die to the pull force, or an increase in the stress within the sense die to the push force.
Dependencies are inferred from the claim text.