Shape measuring instrument

• US 20060271333A1
• Filed: 05/25/2006
• Published: 11/30/2006
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: Matsumoto, Takashi, Okita, Toshiyuki, Niino, Yasuo, Yamamoto, Yoshiji
• Granted Patent: US 7,353,616 B2
• Time in Patent Office: Days
• US Class Current: 702/150
• CPC Class Codes: G01B 5/20 for measuring contours or curvatures

Abstract

A shape measuring instrument is provided as being capable of measuring a surface shape of a target with a small contact force while changing the contact force. A measuring probe 32 is supported while a tilt θ is provided. A retracting force of the measuring force 32 is produced by the tilt θ, and thus, is obtained as mgsig θ which is much small as compared with a self weight “m”. On the other hand, biasing is provided with an extruding force Fc by means of an air cylinder 40. Thus, a contact force of the measuring probe 32 relevant to a work piece W is obtained as a difference between a measuring probe self weight tilt component mgsigθ and the extruding force Fc of the air cylinder 40 (F=Fc−mgsigθ), thus making it possible to reduce a contact force to be very small.

Claims

1. A shape measuring instrument, comprising:

a measuring probe which comes into contact with a surface of a target;

support member configured to support the measuring probe so that an axial direction of the measuring probe is tilted with respect to a horizontal direction and the measuring probe is retracted by a self weight;

biasing member configured to protrude the measuring probe to the side of the target against the self weight; and

a position detector configured to measure an axial position of the measuring probe.

2. A shape measuring instrument as claimed in claim 1, wherein the biasing member is an air cylinder to protrude the measuring probe by an air pressure.

3. A shape measuring instrument as claimed in claim 2, further comprising:

a drive shaft biased by the air cylinder; and

a driven shaft having the measuring probe and interlocked with the drive shaft.

4. A shape measuring instrument as claimed in claim 3, wherein the support member comprises an air bearing for supporting the drive shaft and the driven shaft.

5. A shape measuring instrument as claimed in claim 4, further comprises a common air pressure device supplying air pressure to the air cylinder and the air bearing.

6. A shape measuring instrument as claimed in claim 1, wherein the position detector is a linear scale.

7. A shape measuring instrument, comprising;

contact means for contacting with a surface of a target;

support means for supporting the contact means so that an axial direction of the contact means is tilted with respect to a horizontal direction and the contact means is retracted by a self weight;

biasing means for protruding the contact means to the side of the target against the self weight; and

position detecting means for measuring an axial position of the contact means.