Pressure-sensitive sensor, and grip apparatus and robot manipulator equipped with the same

• US 8,875,584 B2
• Filed: 11/12/2012
• Issued: 11/04/2014
• Est. Priority Date: 12/09/2011
• Status: Expired due to Fees

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Sasajima, Kenta
• Primary Examiner(s): Noori, Max
• Application Number:
  US13/674,906
• Publication Number:
  US 20130145856A1
• Time in Patent Office: 722 Days
• Field of Search: 737/74, 738/18, 738/623.81, 738/623.91, 737/14
• US Class Current: 73/774
• CPC Class Codes: G01L 1/005 by electrical means and not provided for in G01L1/06 - G01L1/22
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress

Abstract

A pressure-sensitive conductive rubber for reference is provided inside a housing in such a state that preload is imposed thereon. A pressure-sensitive conductive rubber for detection is also provided inside the housing in such a state that preload is imposed thereon and an external load acts thereon. A load detecting circuit applies voltage to the pressure-sensitive conductive rubbers to determine the external load based on a difference between a detected value corresponding to electric current flowing through the pressure-sensitive conductive rubber for reference and a detected value corresponding to electric current flowing through the pressure-sensitive conductive rubber for detection.

Claims

1. A pressure-sensitive sensor comprising:

a first pressure-sensitive conductive rubber provided inside a housing in such a state that preload is imposed thereon;

a second pressure-sensitive conductive rubber provided inside the housing in such a state that the preload is imposed thereon and an external load acts thereon;

a load detecting portion for applying voltage to the first and second pressure-sensitive conductive rubbers to determine the external load based on a difference between a first detected value corresponding to electric current flowing through the first pressure-sensitive conductive rubber and a second detected value corresponding to electric current flowing through the second pressure-sensitive conductive rubber; and

a biasing portion for pressing the first and second pressure-sensitive conductive rubbers integrally against an inner wall surface of the housing to impose the preload on the first and second pressure-sensitive conductive rubbers,

wherein the biasing portion has a movable member provided inside the housing to be movable, and an elastic member for biasing the movable member in a direction in which the movable member is pressed against the first and second pressure-sensitive conductive rubbers, and

wherein an opening portion is formed in the housing, and an acting piece is provided on the second pressure-sensitive conductive rubber to project outside of the housing through the opening portion so that the external load will act on the second pressure-sensitive conductive rubber.

2. The pressure-sensitive sensor according to claim 1, wherein said acting piece is covered with a cover member.

3. A grip apparatus equipped with the pressure-sensitive sensor according to claim 1.

4. A robot manipulator equipped with the pressure-sensitive sensor according to claim 1.