Pneumatic counterbalance for optical head gantry
First Claim
1. A pneumatically counterbalanced gantry coupled to a support structure for translation relative to a test object, comprising:
- a gantry including an instrument for performing surface measurements of a test object;
a structure mechanically coupled to the gantry so as to allow said translation of the gantry over a translation path, the translation being opposed by a friction force; and
a pneumatic system coupled to the gantry so as to oppose a movement of the gantry along said translation path;
wherein the pneumatic system is pressurized during operation of the gantry with a pressure sufficient to overcome a force producing said movement of the gantry, but said pressure is not large enough to also overcome said friction force.
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Accused Products
Abstract
A pair of pneumatic cylinders is used to counterbalance the weight of a large gantry supporting the optical head of an interferometric profiler. The gantry is supported by the cylinders within pairs of linear-bearing rail that provide a large vertical travel. The pressure in the cylinders is adjusted so as to provide an upward force sufficient to oppose the weight of the gantry and prevent its descent, but not so great as to cause it to rise. In essence, the counterbalance pressure is adjusted to equilibrate the weight of the gantry in such a way that a small force applied manually upward or downward will cause the gantry to move easily in either direction, thereby making it possible for an operator to position the optical head rapidly and with minimum effort as required for the initial alignment with a test object.
13 Citations
23 Claims
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1. A pneumatically counterbalanced gantry coupled to a support structure for translation relative to a test object, comprising:
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a gantry including an instrument for performing surface measurements of a test object; a structure mechanically coupled to the gantry so as to allow said translation of the gantry over a translation path, the translation being opposed by a friction force; and a pneumatic system coupled to the gantry so as to oppose a movement of the gantry along said translation path; wherein the pneumatic system is pressurized during operation of the gantry with a pressure sufficient to overcome a force producing said movement of the gantry, but said pressure is not large enough to also overcome said friction force. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A pneumatically counterbalanced gantry for an optical profilometer, comprising:
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a gantry including an optical instrument; a support structure including linear bearings mechanically coupled to the gantry for vertical translation of the gantry over a translation path, the translation being opposed by a friction force; a pneumatic system including an air cylinder coupled to the gantry so as to oppose a descent of the gantry along said translation path; a reservoir pneumatically coupled to the cylinder; and a pressure regulator connected to the pneumatic system and to an air source, wherein the pneumatic system is pressurized at all times of operation of the gantry with a pressure sufficient to overcome a downward force produced by the weight of the gantry, but said pressure is not large enough to also overcome said friction force. - View Dependent Claims (12, 13, 14)
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15. Method of supporting a gantry with a counterbalance force for translation relative to a test object, comprising the steps of:
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providing a structure mechanically coupled to the gantry so as to allow said translation of the gantry over a translation path, the translation being opposed by a friction force; and providing a pneumatic system coupled to the gantry so as to oppose a descent of the gantry along said translation path; wherein the pneumatic system is pressurized at all times of operation of the gantry with a pressure sufficient to overcome a downward force produced by the weight of the gantry, but said pressure is not large enough to also overcome said friction force. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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Specification