David E Payette

US Patent:

7059063, Jun 13, 2006

Filed:

Dec 8, 2004

Appl. No.:

11/007689

Inventors:

Wilhelmus Godefridus Weekers - East Greenwich RI, US
Jens Hupkau - Ashaway RI, US
David W. Payette - East Greenwich RI, US

Assignee:

Hexagon Metrology AB - Stockholm

International Classification:

G01B 5/008

US Classification:

33702, 33704, 33503

Abstract:

A machine, such as a coordinate measuring machine, having an element and a structure movable with respect to each other along rails, wherein the rails have a different coefficient of thermal expansion than the structure to which they are attached. In one embodiment, a bar is disposed on the structure opposite the rails. This bar has a coefficient of thermal expansion, a stiffness, a spacing from the neutral axis of the structure, and a cross-sectional dimension such that the bar balances any thermal stresses in the structure caused by differential expansion or contraction of the structure and the rails with temperature changes to minimize any bending of the structure. In one embodiment, two rails are disposed on a beam, and a carriage travels on the two rails. For each rail, there is an associated bar disposed on an opposite surface of the beam. In another aspect, a pin extends into an elongated slot on a slide associated with the structure to allow the structure to expand and contact.

US Patent:

7191541, Mar 20, 2007

Filed:

Dec 6, 2005

Appl. No.:

11/294784

Inventors:

Wilhelmus Godefridus Weekers - East Greenwich RI, US
Jens Hupkau - Ashaway RI, US
David W. Payette - East Greenwich RI, US
John Langlais - Coventry RI, US

Assignee:

Hexagon Metrology AB - Stockholm

International Classification:

G01B 5/008

US Classification:

33702, 33503

Abstract:

A machine, such as a coordinate measuring machine, having a component or element movable with respect to a support structure along rails or guideways, wherein the rails have a coefficient of thermal expansion that is different from that of the support structure to which they are attached. Differential thermal expansion and contraction of the rails with respect to the support structure may be accommodated without binding or distortion of the rails by coupling each guideway to the support structure at two different points. Typically, the coupling at the first point is rigid and prevents any movement of the rail with respect to the support structure. The second coupling includes a flexible component that permits movement of the rail with respect to the support structure in a direction of movement of the element or component. This flexible component may be a leaf spring. In another embodiment, the first coupling may also be flexible.

US Patent:

6829838, Dec 14, 2004

Filed:

Sep 9, 2003

Appl. No.:

10/657903

Inventors:

Wilhelmus Godefridus Weekers - East Greenwich RI
Jens Hupkau - Ashaway RI
David W. Payette - East Greenwich RI

Assignee:

Hexagon Metrology AB - Stockholm

International Classification:

G01B 5008

US Classification:

33702, 33503, 33704

Abstract:

A machine, such as a coordinate measuring machine, having an element and a structure movable with respect to each other along rails, wherein the rails have a different coefficient of thermal expansion than the structure to which they are attached. In one embodiment, a bar is disposed on the structure opposite the rails. This bar has a coefficient of thermal expansion, a stiffness, a spacing from the neutral axis of the structure, and a cross-sectional dimension such that the bar balances any thermal stresses in the structure caused by differential expansion or contraction of the structure and the rails with temperature changes to minimize any bending of the structure. In one embodiment, two rails are disposed on a beam, and a carriage travels on the two rails. For each rail, there is an associated bar disposed on an opposite surface of the beam. In another aspect, a pin extends into an elongated slot on a slide associated with the structure to allow the structure to expand and contact.