US3811157A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tamper-proof fastener
Assignee: Dzus Fastener Co Inc
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Filing: 1972-10-26
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Granted: 1974-05-21
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Expires: 1992-10-26
Abstract
Abstract A tamper-proof fastener adapted to fasten at least two panels together with the panels positioned to form an exterior surface and an interior surface and the panels having aligned openings therein to receive the fastener. The fastener includes a stud and a receptacle both of which are adapted to be partially extended into the openings in the panels. At least one laterally extending prong is on one of the stud and the receptacle and a corresponding cam surface terminating in a locking detent is on the other of the stud and the receptacle so that when the stud and the receptacle are positioned in the openings and rotated with respect to one another in one direction the prong will engage with and follow the cam surface into the locking detent. Thereafter, release of one of the stud and the receptacle will permit only rotation of both the stud and receptacle together. To disassemble, the receptacle is rotated with respect to the stud in a second direction until the prong is moved from the detent over the cam surface to the disengagement position.
Inventors
- 👤 P Schenk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:14
CPC Classifications
F; F16; F16B; F16B21/00; F16B21/02; F16B21/04; Y; Y10; Y10T; Y10T403/00; Y10T403/70; Y10T403/7005; Y10T403/7007
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
379 words
A tamper-proof fastener adapted to fasten at least two panels together with the panels positioned to form an exterior surface and an interior surface and the panels having aligned openings therein to receive the fastener comprising: a stud having a head portion and a body portion; the head portion being of greater diameter than the body portion; the body portion having an outer diameter less than the openings of the panels so as to be extendable therein with the head portion engaging with the exterior surface of the panels; a receptacle havIng a receiving portion and a flange portion; the receiving portion having a diameter less than the diameter of at least one of the openings in the panels so as to be extendable therein with the flange portion engaging with the interior surface of the panels; at least one laterally extending prong on one of said body portion and said receiving portion, and a corresponding cam surface terminating in a locking detent on the other of said body portion and said receiving portion so that when said stud and said receptacle are positioned in said openings and rotated with respect to one another in one direction, said prong will engage with and follow the cam surface into the locking detent whereupon release of one of said stud and receptacle will permit only rotation of both stud and receptacle together, and grasping of both of said members thereafter will permit rotation in another direction with respect to one another until the prong is removed from the detent over the cam surface to the disengagement position; the body portion of the stud containing a plurality of ramps terminating in a plurality of shoulders and spaced about the outer circumferential surface of the body portion of the stud so as to permit insertion of the stud in one direction and to facilitate retention of the stud within the panels when subjected to force in the opposing direction; and a body portion of the stud containing a plurality of radial projections extending therefrom to limit rotation thereof when inserted within the panels thereby alleviating the necessity of grasping of the stud on one side of the panel while rotating the receptacle into locking interengagement therewith from the other side of the panels.
Claim 2
Dependent Claim
379 words
A tamper-proof fastener adapted to fasten at least two panels together with the panels positioned to form an exterior surface and an interior surface and the panels having aligned openings therein to receive the fastener comprising: a stud having a head portion and a body portion; the head portion being of greater diameter than the body portion; the body portion having an outer diameter less than the openings of the panels so as to be extendable therein with the head portion engaging with the exterior surface of the panels; a receptacle havIng a receiving portion and a flange portion; the receiving portion having a diameter less than the diameter of at least one of the openings in the panels so as to be extendable therein with the flange portion engaging with the interior surface of the panels; at least one laterally extending prong on one of said body portion and said receiving portion, and a corresponding cam surface terminating in a locking detent on the other of said body portion and said receiving portion so that when said stud and said receptacle are positioned in said openings and rotated with respect to one another in one direction, said prong will engage with and follow the cam surface into the locking detent whereupon release of one of said stud and receptacle will permit only rotation of both stud and receptacle together, and grasping of both of said members thereafter will permit rotation in another direction with respect to one another until the prong is removed from the detent over the cam surface to the disengagement position; the body portion of the stud containing a plurality of ramps terminating in a plurality of shoulders and spaced about the outer circumferential surface of the body portion of the stud so as to permit insertion of the stud in one direction and to facilitate retention of the stud within the panels when subjected to force in the opposing direction; and a body portion of the stud containing a plurality of radial projections extending therefrom to limit rotation thereof when inserted within the panels thereby alleviating the necessity of grasping of the stud on one side of the panel while rotating the receptacle into locking interengagement therewith from the other side of the panels.
Claim 3
Dependent Claim
92 words
The invention in accordance with claim 1 wherein the prong extends laterally from the body portion of the stud, the receiving portion of the receptacle being hollow and open at the end distal from the flange on the receptacle so as to receive the body portion of the stud containing the prong therein, the interior surface of the receiving portion having the cam surface terminating in a locking detent thereon for engagement with the prong on the stud when the stud and receptacle are interconnected and rotated with respect to one another.
Claim 4
Dependent Claim
37 words
The invention in accordance with claim 2 wherein there are two diametrically opposed laterally extending prongs on the stud and a corresponding cam surface and locking detent for each prong on the interior surface of the receptacle.
Claim 5
Dependent Claim
42 words
The invention in accordance with claim 2 wherein the cam surfaces are of a predetermined length so that only one-quarter of a rotation is needed to shift the stud and receptacle with respect to one another between the locked and unlocked position.
Claim 6
Dependent Claim
72 words
The invention in accordance with claim 1 wherein the head of the stud has an undersurface conforming to the exterior surface of the panels, is of a minimum thickness and of predetermined strength and has a substantially smooth exterior exposed surface so as to minimize the portion of the fastener exposed to the exterior of the panels and to render it difficult to engage and rotate the stud portion of the fastener.
Claim 7
Dependent Claim
67 words
The invention in accordance with claim 1 wherein the flange on the receptacle is of a flexible material and is curved and circular in configuration with only the circumferential extremity thereof in contact with the interior surface of the panels when the receptacle is positioned therein so that when the fastener is engaged deformation of the flange will facilitate travel of the prong along the cam surface.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |