Measuring apparatus

• US 4,078,314 A
• Filed: 05/10/1976
• Issued: 03/14/1978
• Est. Priority Date: 05/13/1975
• Status: Expired due to Term

• Current Assignee: Renishaw PLC
• Original Assignee: Renishaw Electrical Limited (Renishaw PLC), Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: McMurtry, David Roberts
• Primary Examiner(s): Aegerter, Richard E.
• Assistant Examiner(s): Stearns, Richard R.
• Application Number:
  US05/685,073
• Time in Patent Office: 673 Days
• Field of Search: 33/1 M, 33/169 R, 33/172 R, 33/172 E, 33/174 R, 33/174 L, 33/174 P, 33/174 PC
• US Class Current: 33/503
• CPC Class Codes: G01B 7/012 Contact-making feeler heads therefor
• CPC Class Codes: G01B 7/02 for measuring length, width or thickness G01B7/004, G01B7/12 take precedence

Abstract

In a work piece measuring probe the movement of a stylus in three dimensions is sensed by respective inductive transducers having sensing coils fixed to a support in positions adjacent three mutually perpendicular surfaces defined on the stylus.

Claims

1. Probe for use in measuring apparatus comprising a probe support member, a stylus holder, means for supporting the stylus holder on the support member for translation in three orthogonal dimensions, means carried on said stylus holder defining three flat mutually perpendicular surfaces respectively perpendicular to said three dimensions, three proximity sensors secured to the support member in positions confronting the respective flat surfaces and each positioned to sense movement of the adjacent said surface in a direction perpendicular thereto.

2. Probe according to claim 1 comprising a mass of magnetically responsive material extending from the stylus support member and defining said surfaces, and wherein the sensors comprise inductive means cooperating to sense movement of the mass.

3. Probe according to claim 1 comprising an extension extending from the stylus holder, a head of magnetically responsive material provided at the free end of the extension and defining said surfaces, and wherein the sensors comprise inductive means cooperating to sense movement of the head.

4. Probe according to claim 1 comprising an extension connected to the stylus holder to move together therewith, a head secured to the extension at the end thereof remote from the stylus holder, the head defining said three surfaces, one of said surfaces facing away from the stylus holder, the head being spaced from said sensors with clearance therebetween, the head being made of magnetically responsive material, and wherein the sensors comprise inductive means for sensing movement of the head.

5. Probe according to claim 1 wherein said means for supporting the stylus support member comprise a first, a second and a third parallelogram unit, each of said units comprising a pair of spaced apart rigid members and a pair of spaced resilient members secured to the rigid members in position therebetween, said units being connected in series in the sense of there being one rigid member common to the first and second units and another rigid member common to the second and third units, the remaining rigid members of the first and third units being common respectively to the stylus holder and the support member.

6. Probe according to claim 1 wherein said means for supporting the stylus holder comprise a first and a second rigid member arranged in spaced relationship, a pair of resilient members connected to the rigid members in position therebetween, said first rigid member constituting said stylus holder, a first extension constituting a stylus connected to the side of the first rigid member facing away from the second rigid member, means defining an opening in the second rigid member, a second extension connected to the side of the first rigid member confronting the second rigid member and extending with clearance through said opening, the second extension having an end situated at the side of the second rigid member facing away from the first rigid member, and said flat surfaces being provided on said end of the second extension.