US3685716A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rivet center detector mechanism embodying strain gauge
Assignee: Rohr Inc
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Filing: 1971-04-29
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Granted: 1972-08-22
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Expires: 1991-04-29
Abstract
Abstract To determine whether or not a rivet has been delivered to, and is properly centered between a pair of complementary recesses provided in the fingers of an automatic riveting machine, a pair of strain gauges are operatively associated with the rivet holding fingers, the strain gauges being incorporated in opposite sides of a balanced, bridged circuit which is connected to actuate, selectively, a plurality of detectors, each detector, when actuated, indicating a relative separated condition of the rivet holding fingers.
Inventors
- 👤 Thomas T Frankie
- 👤 Larry B Pascoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:48
CPC Classifications
B; B21; B21J; B21J15/00; B21J15/10; B21J15/30; B21J15/32; B21J15/28
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
174 words
A rivet center detector for an automatic riveting machine having a pair of rivet holding fingers with complementary recesses therein for receiving a rivet of known size in centered, seated relation in said recesses, and means biasing the fingers toward each other to rivet holding position, said detector comprising; at least one strain gauge operatively associated with at least one of the fingers in a manner to vary the electrical resistance of said at least one strain gauge in one direction upon moving said at least one finger in a direction to increase the separation between the fingers, and to vary the resistance of said at least one strain gauge in the opposite direction upon moving said at least one finger in the opposite direction to thereby decrease the separation between the fingers, a bridged circuit incorporating said at least one strain gauge, and detector means responsive to each of a selected plurality of unbalanced conditions of the bridged circuit caused by such variations in the resistance of said at least one strain gauge.
Claim 2
Dependent Claim
174 words
A rivet center detector for an automatic riveting machine having a pair of rivet holding fingers with complementary recesses therein for receiving a rivet of known size in centered, seated relation in said recesses, and means biasing the fingers toward each other to rivet holding position, said detector comprising; at least one strain gauge operatively associated with at least one of the fingers in a manner to vary the electrical resistance of said at least one strain gauge in one direction upon moving said at least one finger in a direction to increase the separation between the fingers, and to vary the resistance of said at least one strain gauge in the opposite direction upon moving said at least one finger in the opposite direction to thereby decrease the separation between the fingers, a bridged circuit incorporating said at least one strain gauge, and detector means responsive to each of a selected plurality of unbalanced conditions of the bridged circuit caused by such variations in the resistance of said at least one strain gauge.
Claim 3
Dependent Claim
40 words
A rivet center detector as claimed in claim 1 wherein two strain gauges are operatively associated one with each of the fingers, and said strain gauges are incorporated in the bridged circuit so that their unbalancing effect thereon is cumulative.
Claim 4
Dependent Claim
53 words
A rivet center detector as claimed in claim 2 wherein the strain gauges are so located relative to the fingers that a change in separation of the fingers resulting in a decrease of the resistance of one of the strain gauges results in an increase of the resistance of the other strain gauge.
Claim 5
Dependent Claim
91 words
A rivet center detector as claimed in claim 1 wherein spring means biases the fingers toward each other, said spring means having a portion thereof which is bent in one direction by an increase in separation between the fingers, and is bent in the opposite direction by a decrease in such separation, and said at least one strain gauge is mounted on such spring portion for selective increase and decrease in the resistance of said at least one strain gauge upon bending such portion selectively in each of two opposite directions.
Claim 6
Dependent Claim
45 words
A rivet center detector as claimed in claim 4 wherein a strain gauge is mounted one on each of two opposite sides of said spring means portion and the strain gauges are so incorporated in the bridged circuit that their unbalancing effect thereon is cumulative.
Claim 7
Dependent Claim
20 words
A rivet center detector as claiMed in claim 4 wherein the spring means is an enclosing band of spring metal.
Claim 8
Dependent Claim
46 words
A rivet center detector as claimed in claim 5 wherein the spring means is an enclosing, generally C shape band of spring sheet metal and the strain gauges are mounted one inside and the other outside of the band and substantially medially between the ends thereof.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |