US3812758A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bolt head which measures and maintains preload
Assignee: Kaman Aerospace Corp
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Filing: 1972-10-24
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Granted: 1974-05-28
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Expires: 1992-10-24
Abstract
Abstract A bolt providing an indication of pre-load and continuous load thereafter wherein the bolt head has recesses on both sides thereof leaving a central ring which functions as a diaphragm spring and deflects along the bolt axis as a function of load. An indicator pin is mounted in or forms part of the ring so as to deflect with the ring, moving through a passage in an indicator washer or ring which closes the top recess and which permits a ready determination, by comparison of the relative positions of pin and indicator ring, of bolt pre-load. A further embodiment of the pre-load indicating device eliminates the indicator pin and replaces the indicator washer with a transverse buckled column, which indicates load along the bolt axis by the deflected location of the buckled column.
Inventors
- 👤 R Bossler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:06
CPC Classifications
F; F16; F16B; F16B31/00; F16B31/02; F16B31/025; G; G01; G01L; G01L5/00; G01L5/24
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
149 words
A bolt comprising: a first member having a shaft portion extending along a bolt axis and terminating in a head with a first annular recess on one side of said head between a surface for bearing against a clamped member and the juncture of said shaft and said head and a second annular recess on the opposite side of said head so as to define a ring between said recesses which deflects along the bolt axis with increasing and decreasing load and having an indicator pin with a portion joined to said defined ring for movement therewith and a portion extending out of said defined ring away from said shaft portion, and an annular indicator ring mounted in said head and having a central passage through which said indicator pin extends so that the relative position of said pin and said indicator ring indicates the load on said bolt.
Claim 2
Dependent Claim
149 words
A bolt comprising: a first member having a shaft portion extending along a bolt axis and terminating in a head with a first annular recess on one side of said head between a surface for bearing against a clamped member and the juncture of said shaft and said head and a second annular recess on the opposite side of said head so as to define a ring between said recesses which deflects along the bolt axis with increasing and decreasing load and having an indicator pin with a portion joined to said defined ring for movement therewith and a portion extending out of said defined ring away from said shaft portion, and an annular indicator ring mounted in said head and having a central passage through which said indicator pin extends so that the relative position of said pin and said indicator ring indicates the load on said bolt.
Claim 3
Dependent Claim
50 words
A bolt as in claim 1, wherein said first recess is concave, with the center of curvature falling on a line extending parallel to said bolt axis and said second recess extends from a maximum depth near the periphery of said head to a minimum depth near said bolt axis.
Claim 4
Dependent Claim
19 words
A bolt as in claim 2, wherein said pin is cylindrical with its axis coincident with said bolt axis.
Claim 5
Dependent Claim
14 words
A bolt as in claim 1, wherein said head has peripheral torque applying surfaces.
Claim 6
Dependent Claim
29 words
A bolt as in claim 1, wherein said indicator ring is mounted in a groove at the outer periphery of said second recess and substantially closes said second recess.
Claim 7
Dependent Claim
106 words
A bolt comprising: a first member having a shaft portion extending along a bolt axis and terminating in a head with a first annular recess on one side of said head between a surface for bearing against a clamped member and the juncture of said shaft and said head and a second annular recess on the opposite side of said head so as to define a ring between said recesses which deflects along the bolt axis with increasing and decreasing load, and a transverse buckled column mounted in said second recess so that the relative position of said buckled column indicates the load on said bolt.
Claim 8
Dependent Claim
106 words
A bolt comprising: a first member having a shaft portion extending along a bolt axis and terminating in a head with a first annular recess on one side of said head between a surface for bearing against a clamped member and the juncture of said shaft and said head and a second annular recess on the opposite side of said head so as to define a ring between said recesses which deflects along the bolt axis with increasing and decreasing load, and a transverse buckled column mounted in said second recess so that the relative position of said buckled column indicates the load on said bolt.
Claim 9
Dependent Claim
25 words
A bolt as in claim 6, wherein said second recess is at least partially filled with protective material to shield said buckled column from damage.
Claim 10
Dependent Claim
14 words
A bolt as in claim 6, wherein said head has peripheral torque applying surfaces.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |