Apparatus for measuring mechanical forces and force actions

• US 5,335,544 A
• Filed: 02/21/1992
• Issued: 08/09/1994
• Est. Priority Date: 06/23/1989
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Riethmuller, Werner, Wagner, Bernhard, Schnakenberg, Uwe, Benecke, Wolfgang
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US07/778,893
• Time in Patent Office: 900 Days
• Field of Search: 73/862.382, 73/514, 73/517 R, 73/517 B, 361/280, 338/5, 338/46, 437/228
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/12 by alteration of electrical resistance G01P15/0897, G01P15/105 take precedence
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends

Abstract

An apparatus for measuring mechanical forces and force actions by means of body, a restoring element and a movable mass, with elements for limiting the deflections of the movable mass. The movable mass is deflected against the resistance of the restoring element under the influence of a mechanical force which, with the aid of sensors, is converted into electrical signals. The elements for limiting deflection include at least two parallel tongues fixed respectively to the restoring element and to the movable mass, and a bridge element fixed at right angles to one of the tongues, at least partly overlapping the other of the tongues.

Claims

1. Apparatus for measuring mechanical forces and force actions, comprising:

a fixed body;

a movable mass which is displaceable relative to said fixed body in at least two directions;

a resilient restoring element coupling said fixed body to said movable mass; and

first and second means for limiting displacement of said movable mass in each of said two directions, each of said first and second means comprising;

at least a pair of first rigid tongues connected at an end thereof to one of said restoring element and said movable mass, and at least a pair of second rigid tongues connected at an end thereof to said fixed body;

said first and second rigid tongues being parallel to and overlapping each other;

and a bridge element arranged at right angles to said tongues, said bridge element being connected to one of said pairs of rigid tongues, and extending over the other of said pairs of rigid tongues, in a direction of displacement of said movable mass.

2. Apparatus according to claim 1, wherein said restoring element is constructed as a bender bar fixed on one end to the body and having a free end which carries the movable mass;

two rows of tongues connected to the bender bar are interleaved with tongues connected to the fixed body in comb-like manner; and

the tongues connected to the fixed body and the tongues connected to the bender bar respectively are connected by cantilever bridge elements, which span the intermediate tongues with a predeterminable clearance.

3. Apparatus according to claim 1, wherein deformation of the restoring element caused by a force action is determined by means of integrated resistance strain gauges.

4. Apparatus according to claim 2, wherein deformation of the restoring element caused by a force action is determined by means of integrated resistance strain gauges.

5. Apparatus according to claim 1, wherein facing plates are fitted to parts fixed to the body and movable parts of the apparatus and form a capacitor with a variable plate spacing, the acting force being measured by the determination of the capacitance change.

6. Apparatus according to claim 2, wherein facing plates are fitted to parts fixed to the body and movable parts of the apparatus and form a capacitor with a variable plate spacing, the acting force being measured by the determination of the capacitance change.

7. Apparatus according to claim 1, wherein the fixed body, the restoring element and the tongues are made from silicon or a silicon compound, and the bridges for connecting the tongues are made from a metal, silicon or a silicon compound.

8. Apparatus for measuring mechanical forces and force actions, comprising:

a fixed body;

a movable mass which is displaceable relative to said fixed body in at least two directions;

a resilient restoring element coupling said fixed body to said movable mass; and

first and second means for limiting displacement of said movable mass in each of said two directions, each of said first and second means comprising;

at least one first rigid tongue connected at an end thereof to said restoring element or said movable mass, and at least one second rigid tongue connected at an end thereof to said fixed body;

said first and second rigid tongues being parallel to and overlapping each other;

and a bridge element arranged at right angles to said tongues, said bridge element being connected to one of said rigid tongues, and extending over the other of said rigid tongues, in a direction of displacement of said movable mass.