Counterweight for coordinate measuring machine

• US 4,835,871 A
• Filed: 10/31/1986
• Issued: 06/06/1989
• Est. Priority Date: 10/31/1986
• Status: Expired due to Term

• Current Assignee: Hexagon Metrology AB (Hexagon AB)
• Original Assignee: Brown & Sharpe Manufacturing Company (BNS Holding Incorporated)
• Inventors: Pesikov, Vitaly I.
• Primary Examiner(s): HAROIAN, HARRY
• Application Number:
  US06/925,323
• Time in Patent Office: 949 Days
• Field of Search: 33/1 M, 33/503, 33/504, 33/23.05, 33/505, 33/169 R, 33/170
• US Class Current: 33/1.00M
• CPC Class Codes: B23Q 11/0025 using resilient means, e.g. springs, hydraulic dampers
• CPC Class Codes: G01B 5/0016 due to weight on machine tools B23Q11/001

Abstract

Apparatus for counterbalancing a vertically movable element of a machine includes an air cylinder attached to the movable element on the axis of movement and having a small axial opening at its upper end. A piston located in the air cylinder is attached to a fixed machine element by a nonelastic, flexible member such as a thin, nylon-jacketed wire passing through the axial opening in the cylinder. Air under pressure sufficient to counterbalance the weight of the movable element is supplied to the space between the piston and the axial opening in the cylinder. The flexible member makes the counterbalancing assembly relatively insensitive to misalignment and vibration. Air is permitted to leak around the piston to reduce friction and to relieve pressure buildup during downward movement. In another embodiment, the air cylinder is attached to the fixed machine element.

Claims

1. Apparatus for counterbalancing a vertically movable element of a machine comprising:

a cylinder defining an elongated cylindrical space attached to the movable element with its axis parallel to the direction of movement of said movable element and having a small axial opening at its upper end, said opening in said cylinder being defined by a low friction jewel;

a piston located in said cylindrical space for axial movement therein;

a machine element fixed in the vertical direction and having a portion aligned with the axis of said cylinder;

connection means passing through said opening in said cylinder for connecting said piston and said portion of said fixed machine element while substantially eliminating friction and wear at said opening caused by misalignment between said movable element and said fixed machine element, said connection means comprising an elongated, thin stranded wire that is nonelastic in a longitudinal direction and is free to bend and flex in a transverse direction; and

means for supplying air under pressure to the portion of said cylindrical space between said piston and said opening in said cylinder sufficient to counterbalance the weight of said movable element.