Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Headed fastener element with nut – washer – securing means or cap – Deformable securing means
Reexamination Certificate
1999-05-18
2001-06-05
Estremsky, Gary W. (Department: 3627)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Headed fastener element with nut, washer, securing means or cap
Deformable securing means
C411S339000
Reexamination Certificate
active
06241443
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a fastener for securing workpieces together and more particularly to a multiple piece fastener including a pin and a collar.
One example of such a fastener can be seen in U.S. Pat. No. 4,846,611, “Fastener System and Fastener for Shipping Containers and the Like” issued to Sadri et al., assigned to the same assignee as the present invention and incorporated herein by reference. This patent discloses an elongated pin having a head portion and a shank portion. The shank portion includes a set of helical splines to engage a bore in a tubular collar. As the collar is pressed onto the pin, the splines flow the collar material into grooves associated with the splines to provide an interference engagement between the two. To keep the splines from significantly expanding the collar radially as it is pressed onto the pin, the degree of interference between the splines and the bore and the relative hardness of the pin to the collar are controlled. In the disclosed preferred embodiment, the pin has been heat-treated and has a hardness of approximately two times the hardness of the collar.
Another example of such a fastener can be seen in U.S. Pat. No. 4,627,775, “Blind Fastener with Grip Compensating Means”, issued to Dixon, assigned to the same assignee as the present invention and incorporated herein by reference. This patent discloses a blind fastener including an elongated pin and a tubular collar. The pin includes a single forming or extruding land having a diameter that is larger than an inner diameter of the collar. As the collar is pressed onto the pin, the extruding portion extrudes a portion of the collar material into a lock groove associated with the extruding land to lock the collar to the pin. This operation also results in the radial expansion of the collar due to the force from the extruding land. In one embodiment disclosed, the pin has been heat-treated to a hardness of R
c
48-52.
SUMMARY OF THE INVENTION
The present invention provides a fastener for fastening multiple workpieces (or multilaminate workpiece) together. The fastener includes a pin and a collar for engaging the pin. The pin includes a pin head for engaging one exposed surface of the workpieces and a pin shank for positioning through a bore in the workpieces. The pin shank includes, sequentially moving away from the pin head, a shoulder, a second working surface having a second working edge with a second outer diameter, a second locking groove having an inner diameter less than the second outer diameter, a first working surface having a first working edge with a first outer diameter, a first locking groove having an inner diameter less than the first outer diameter, a breakneck groove and a pin tail having a plurality of pulling grooves. The collar includes an enlarged head and a through bore.
The collar is placed over the pin shank and an installation tool is used to grip the pulling grooves. The installation tool presses the collar onto the pin. As this happens, the first working edge engages the through bore of the collar and moves material from the through bore into the first locking groove to create a lock between the collar and the pin. Continued movement of the collar with respect to the pin engages the second working edge with the through bore of the collar and moves material from the through bore into the second locking groove to create an additional lock between the collar and the pin.
In one embodiment, the outer diameter of the second working edge is greater than the outer diameter of the first working edge so that the second working edge engages collar material not engaged by the first working edge. Alternatively, or in conjunction with the first embodiment, the first working edge can be provided with a non-round cross-section so that it only engages selected arcuate sections of the collar through bore. The second working edge is also provided with a non-round cross-section, rotated with respect to the first working edge cross-section so that the second working edge engages different arcuate sections of the collar through bore than the first working edge engages.
It is preferred that the proportions and positioning of the working surfaces, working edges, locking grooves and collar through bore be set such that as the first locking groove fills with collar material and a push-out value resulting from the lock of the first locking groove stops increasing, the push-out value resulting from the lock of the second locking groove continues to increase. This staging by use of the multiple working edges and locking grooves helps maximize the push-out value of the fastener over a broader clamping range than the use of only one such working edge/locking groove combination. Additional working edge/locking groove combinations can also be utilized. As the workpieces become firmly clamped between the pin and the collar, additional application of force by the installation tool will break off the pin tail at the breakneck groove.
The present invention can also be utilized with blind-type fasteners.
The use of the staged locking system described above also allows the use of a pin that has only been hardened through the working process and does not require additional heat-treating.
It is therefore an object of the present invention to provide a staged fastening system that maximizes the gripping force of the fastening system over a broad clamping range.
It is a further object of the present invention to provide a fastener having an increased resistance to pin push-out and loss of clamp loads over extended periods of use.
It is a further object of the present invention to provide a pin and collar type fastener where the pin needs no additional hardening beyond the work-hardening imparted by the pin manufacturing process.
It is a further object of the present invention to provide a fastener especially adapted for manufacturing shipping containers and the like having multilaminate constructions.
The foregoing and other objects, features, characteristics and advantages of the present invention as well as the methods of operation and functions of the related elements of structure, and the combination of parts and economies of manufacture, will be apparent from the following detailed description and the appended claims, taken in connection with the accompanying drawings, all of which form a part of the specification, wherein like reference numerals designate corresponding parts in the various figures.
REFERENCES:
patent: 3277771 (1966-10-01), Reynolds
patent: 3515419 (1970-06-01), Baugh
patent: 4127435 (1978-11-01), Angelosanto et al.
patent: 4405273 (1983-09-01), Ruhl et al.
patent: 4473914 (1984-10-01), Haft
patent: 4609317 (1986-09-01), Dixon et al.
patent: 4615655 (1986-10-01), Dixon
patent: 4635310 (1987-01-01), Kendall
patent: 4863325 (1989-09-01), Smith
patent: 5054977 (1991-10-01), Schultz
patent: 5228817 (1993-07-01), Cosenza
patent: 5562379 (1996-10-01), Rausch
patent: 5810530 (1998-09-01), Travis
Corbett Robert J.
Harbin Thomas
Estremsky Gary W.
Harness & Dickey & Pierce P.L.C.
Huck International Inc.
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