Force sensing apparatus

• US 4,836,034 A
• Filed: 07/14/1987
• Issued: 06/06/1989
• Est. Priority Date: 07/15/1986
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ohta, Eiichi, Ebi, Yutaka, Eguti, Hirotoshi, Kimura, Yuhji, Izumi, Kohji
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): Raevis, Robert R.
• Application Number:
  US07/073,290
• Time in Patent Office: 693 Days
• Field of Search: 73/794, 73/862.35, 73/862.33, 73/862.32, 73/862.65, 73/862.64, 73/862.62, 73/862.66, 73/862.04, 73/862.05, 73/862.06 , 73/862.47, 73/862.48
• US Class Current: 73/862.044
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 5/162 of piezoresistors

Abstract

A force sensing apparatus comprising:

a plate-like strain producing body;

a central portion disposed integrally at a center of the body and having higher rigidity than the body;

a peripheral portion disposed integrally along a periphery of the body and having higher rigidity than the body; and

a plurality of sensing elements formed on a surface of the body and having an electric resistance variable in accordance with a deformation thereof in order to simultaneously sense mutually orthogonal X, Y and Z axial components of an external force applied to the body via the central portion or the peripheral portion, the sensing elements being on the same plane.

Claims

1. A force sensing apparatus comprising:

(a) a plate-like body, said plate-like body comprising;

(i) a central portion disposed integrally at the center of said plate-like body and having a first rigidity;

(ii) a thin flat plate portion disposed integrally around said central portion and having a second rigidity lower than the first rigidity; and

(iii) a peripheral portion disposed integrally along the periphery of said platelike body and having a third rigidity higher than the second rigidity;

(b) a plurality of sensing elements formed on a planar surface of said plate-like body and having an electric resistance variable in accordance with a deformation thereof in order to simultaneously sense mutually orthogonal X, Y, and Z axial components of an external force applied to said plate-like body via said central portion or said peripheral portion; and

(c) a plurality of holes provided along a circumference of a circle located on said thin flat plate portion, the number of said holes being 8 or a multiple of 8,

wherein;

(d) each one of said plurality of sensing elements is formed on an expanding portion of said plate-like body defined by two adjacent holes and in which, during use of said force sensing apparatus, the distribution of stresses is uniform.

2. A force sensing apparatus of claim 1 wherein:

(a) said plate-like body is made of an aluminum alloy or stainless steel and

(b) each one of said plurality of sensing elements is made of a thin semiconductor film.

7. A force sensing apparatus of any one of claims 1 to 6 wherein:

(a) said plate-like body is made of an aluminum alloy or stainless steel and

(b) each of said plurality of first, second, and third sensing elements is made of a thin semiconductor film.

3. A force sensing apparatus comprising:

(a) a plate-like body, said plate-like body comprising;

(i) a central portion disposed integrally at the center of said plate-like body and having a first rigidity;

(ii) a thin flat plate portion disposed integrally around said central portion and having a second rigidity lower than the first rigidity; and

(iii) a peripheral portion disposed integrally along the periphery of said plate-like body and having a third rigidity higher than the second rigidity;

(b) a plurality of first sensing elements provided on an X axis on said plate-like body and having electric resistances variable in accordance with deformation thereof for sensing a moment around a Y axis on said platelike body orthogonal to the X axis on said platelike body;

(c) a plurality of second sensing elements provided on the Y axis having electric resistances variable in accordance with deformation thereof for sensing a moment around the X axis; and

(d) a plurality of third sensing elements provided on a Z'"'"' and a Z" axes on said plate-like body in the plane defined by the X and Y axes at angles of 45°

to the X and Y axes, respectively, for sensing a force in the direction of a Z axis perpendicular to the surface of said plate-like body,

(e) said plurality of first, second, and third sensing elements being co-planar.

4. A force sensing apparatus of claim 3, wherein a plurality of holes are provided along a circumference of a circle located on said thin flat plate portion.

5. A force sensing apparatus of claim 4, wherein the number of holes is 8 or a multiple of 8.

6. A force sensing apparatus of claim 5, wherein each of said plurality of first, second, and third sensing elements is formed on an expanding portion of said plate-like body defined by two adjacent holes and in which, during use of said force sensing apparatus, the distribution of stresses is uniform.