US3796493A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring pitch of precision lead-screw by light-wave interference
Assignee: Tokyo Institute of Technology
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Filing: 1971-12-22
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Granted: 1974-03-12
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Expires: 1991-12-22
Abstract
Abstract A pair of feelers are brought into contact with the same thread flank of a screw to be measured at two points whose phase differs from each other by 180*. The pair of feelers are mounted on a slide movable in any direction without rotation on a carriage in a plane parallel to a plane in which the carriage travels in the axial direction of the screw to be measured. The feed of the carriage per revolution of a screw to be measured is so adjusted as to be approximately equal to the pitch of the screw. The midpoint between the spherical ends of the pair of feelers in contact with the same thread flank is located at the corner point or vertex of a corner cube reflector which is formed upon the slide. The light beam from the corner cube reflector is reflected by a reflector. The pitch of the screw is measured by the lightwave interference between the light beams separated by a halfmirror, one of which is reflected at the corner cube reflector and the said reflector. The measured value is compared with a reference pitch.
Inventors
- 👤 A Yamamoto
- 👤 I Yoshimoto
- 👤 Y Tanimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:52
CPC Classifications
G; G01; G01B; G01B5/00; G01B5/14; G01B5/16; G01B5/163
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
198 words
A pitch measuring apparatus for measuring a pitch of a screw comprising a means for holding a screw to be measured for rotation about the axis thereof; b means for rotating said screw about the axis thereof; c a carriage adapted to displace in parallel with said axis; d a slide mounted on said carriage movable in any direction without rotation in a plane in parallel to a plane in which said carriage travels; e a pair of feelers spaced a constant distance apart and mounted on said slide in such a manner that said pair of feelers can make contact with the same thread flank of said screw at two points whose angular displacement with respect to the axis of the screw is 180*; f a corner cube reflector formed on said slide and having a corner point at the midpoint between said feelers; g a light source adapted to emit light in parallel with said axis; h means for reflecting said light emitted from said light source in said corner cube reflector and reversing said light reflected in said corner cube reflector to cause the light-wave interference; and i means for detecting said light wave interference.
Claim 2
Dependent Claim
198 words
A pitch measuring apparatus for measuring a pitch of a screw comprising a means for holding a screw to be measured for rotation about the axis thereof; b means for rotating said screw about the axis thereof; c a carriage adapted to displace in parallel with said axis; d a slide mounted on said carriage movable in any direction without rotation in a plane in parallel to a plane in which said carriage travels; e a pair of feelers spaced a constant distance apart and mounted on said slide in such a manner that said pair of feelers can make contact with the same thread flank of said screw at two points whose angular displacement with respect to the axis of the screw is 180*; f a corner cube reflector formed on said slide and having a corner point at the midpoint between said feelers; g a light source adapted to emit light in parallel with said axis; h means for reflecting said light emitted from said light source in said corner cube reflector and reversing said light reflected in said corner cube reflector to cause the light-wave interference; and i means for detecting said light wave interference.
Claim 3
Dependent Claim
31 words
The pitch measuring apparatus as set forth in claim 1 wherein said screw is located in the space defined in the proximity of the corner point of said corner cube reflector.
Claim 4
Dependent Claim
49 words
A pitch measuring apparatus as set forth in claim 1 wherein the diameter of the spherical ends of said pair of feelers in contact with said same thread flank is made equal to that of the steel balls which are retained in a ball retaining screw to be measured.
Claim 5
Dependent Claim
50 words
A pitch measuring apparatus as set forth in claim 1 wherein the diameter of the spherical ends of said pair of feelers in contact with said same thread flank is made substantially equal to that of the steel balls which are retained by a ball retaining screw to be measured.
Claim 6
Dependent Claim
132 words
A pitch measuring apparatus as set forth in claim 1 wherein said light wave interference means comprises a a light source; b a half-mirror adapted to split light from said light source into two light beams by reflection and transmission; c said corner cube reflector in which said light beam transmitted through said half-mirror is reflected; d a first reflector adapted to reflect back and reverse in direction the light beam emerging from said corner cube reflector; e a second reflector disposed so as to reflect back said light reflected by said half miRror back toward said half mirror to cause the light-wave interference with said light emerging from said corner cube reflector after said reflection by said first reflector; and f a light-wave interferometer positioned to detect said light wave interference.
Claim 7
Dependent Claim
42 words
A pitch measuring apparatus in accordance with claim 1, wherein said corner cube reflector is comprised of three reflective surfaces mounted in three planes at right angles with respect to each other, the three planes being positioned to define an imaginary hexahedron.
Claim 8
Independent Claim
170 words
A method for measuring a pitch of a screw comprising holding and locating a screw to be measured between the centers of a headstock and a tailstock of a pitch measuring apparatus; contacting the same thread flank of said screw with a pair of feelers at two points whose angular displacement with respect to the axis of the screw is 180*, fixing said pair of feelers to a slide mounted and movable in any dirction without rotation on a carriage in a plane parallel with a plane in which said carriage travels on a bed of said pitch measuring apparatus; rotating said screw to be measured about the axis thereof while said contact of said pair of feelers with said same thread flank is maintained, and reflecting light from a light source off of a corner cube reflector positioned with a corner point at the mid-point between said feelers for determining the pitch of said screw by measuring the displacement of said slide in the axial direction of said screw.
Claim 9
Independent Claim
170 words
A method for measuring a pitch of a screw comprising holding and locating a screw to be measured between the centers of a headstock and a tailstock of a pitch measuring apparatus; contacting the same thread flank of said screw with a pair of feelers at two points whose angular displacement with respect to the axis of the screw is 180*, fixing said pair of feelers to a slide mounted and movable in any dirction without rotation on a carriage in a plane parallel with a plane in which said carriage travels on a bed of said pitch measuring apparatus; rotating said screw to be measured about the axis thereof while said contact of said pair of feelers with said same thread flank is maintained, and reflecting light from a light source off of a corner cube reflector positioned with a corner point at the mid-point between said feelers for determining the pitch of said screw by measuring the displacement of said slide in the axial direction of said screw.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |