Strap fastener

Details Strap fastener Strap fastener

1999-05-21

2001-07-10

Brittain, James R. (Department: 3626)

Buckles, buttons, clasps, etc.

Separable-fastener or required component thereof

With third detached member completing interlock

C024S168000

Reexamination Certificate

active

06256847

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to fasteners and to devices for preventing electrostatic discharge. More particularly, the present invention relates to a fastener which can be polymeric.
BACKGROUND OF THE INVENTION
Electrostatic discharge, as well as the mere presence of a static electric field, can be extremely detrimental to sensitive electronic (solid-state) parts. Modern semiconductors and integrated circuits may be degraded or destroyed by such static buildup. One common tool used to control static discharge and buildup is a conductive grounding tether which is designed to drain away excess electrostatic charge. A general discussion of such devices can be found in U.S. Pat. Nos. 4,677,521, 5,018,044, and 5,184,274.
The wristbands and tethers disclosed in these patents have many parts which add to the cost of the devices. While those devices have features which make them advantageous for particular uses, they are relatively expensive when considered for the most basic task of safe and effective grounding. Less expensive and simpler bands have been designed, such as those shown in U.S. Pat. Nos. 3,857,397 and 4,698,724, but those designs suffer from certain inherent limitations. For example, both of these designs are unitary wristband/tethers, meaning that if the tether portion of the device breaks, the wristband becomes useless, or vice-versa, and also meaning that if the user desires to walk away from his or her workstation he or she must completely take off the wristband, or must allow the tether portion to dangle, in contrast with the designs that allow the tether to be detachably connected to the wristband. Both of these designs are also ill-suited for use in a dual conductor system (such as that shown in the '044 patent). Finally, the means for adjusting the effective size of the wristband must be applied separately to the band, such as the hook-and-loop fastening strips in the '397 patent, or the adhesive layer in the '724 patent This separate application step increases processing cost, but it is critical that the device achieve a proper exact adjustment since it must have good contact with the skin to be sufficiently conductive, and yet not be so tight to constrict circulation or otherwise be uncomfortable.
Alternatives to the hook and loop fastening described in the '397 patent require pressing together overlapping portions of a strap to establish interlocking contact to secure the strap in a looped configuration of desired dimensions. For example, U.S. Pat. Nos. 3,514,815, 3,518,727, and 4,872,242 provide elongated, flexible straps with means on their upper and lower surfaces for connection between surfaces. When formed into a loop, the straps are positioned with teeth on one surface adjacent to valleys on the opposite surface. The teeth and valleys will nest together, under suitable pressure, so that interlocking connection between teeth and valleys occurs. Upon wrapping one of the disclosed flexible straps around, for example, a cable bundle, the teeth and valleys provide interlocking means capable of self-engagement along a length where the strap overlaps itself.
U.S. Pat. Nos. 4,178,751 and 4,941,236 disclose interlocking structures for securing straps, associated with watches, around the wearer's wrist. The '236 patent discloses an interlocking means in the form of a clasp for a watch band. In this case the free end portions of the band include magnetic segments. End portions may be secured together under the influence of the magnetic force. The strap ends have surfaces contacting one another where they overlap with mutually nesting, uniformly spaced interlocking teeth; the magnetic segments provide a holding force resisting separation of the end portions while the nested teeth prevent sliding disengagement between the ends. In the '751 patent, an injection-molded casing for a watch module includes an integrally molded wristband. The casing also includes a metal form partially covered by integrally molding a thermoplastic material over the form and may, by design, leave sections of the underlying metal exposed. Attachment of the wristband to the wearer's wrist involves clasp portions that nest together, held by interlocking projections formed at the edges of the clasp portions.
Known fasteners, including hook and loop strips and interlocking structures, present some difficulties when adjusting the loop size of a strap. The fastening characteristics of hook and loop closures ensure that, whenever the hooked material and the looped fabric are near each other they tend to cling to one another. Premature clinging may occur requiring several attempts to adjust the loop to the desired size. The hook portions pick up undesirable debris like lint, hair, and other fibrous matter that impairs performance. Interlocking straps include molded rib structures that need aligning before interlocking the fastener components, and may be difficult to remove or may otherwise be inflexible.
It would, therefore, be desirable and advantageous to devise a durable low-cost, low-part count wristband (which can be made of a flexible polymer or polymeric material) with secure fastening, easy removal and convenient strap loop size adjustment.
SUMMARY OF THE INVENTION
A reclosable fastener includes an insert element and a retention element. The insert element has opposing surfaces, opposing side edges, and at least one end. The retention element has a central longitudinal axis, opposing surfaces, opposing side edges, at least one end. The retention element also has a plurality of discrete, spaced projections extending generally orthogonally from at least one side edge of one of the opposing surfaces. At least one of the projections has a free end that includes a hook portion extending generally orthogonally from the projection toward the central longitudinal axis. The width of the insert element can be equal to or less than the width of the retention element The fastener operates in a first condition and a second condition. In the first condition the fastener is open and the insert element is disengaged from the retention element. In the second condition the fastener is closed and the insert element engages the retention element such that the hook portion of the retention element faces the adjacent surface of the insert element.
In moving from the first condition to the second condition the insert element engages the retention element by overlaying onto the retention element and being pressed into place. In moving from the second condition to the first condition the insert element disengages from the retention element by peeling from the retention element.
The fastener has a shear holding function that is independent of the force required to engage and disengage the insert element and the retention element to move from the first condition to the second condition and from the second condition to the first condition.
Optionally, in the second condition the opposing side edges of the insert element can contact the spaced projections of the retention element.
Optionally, the insert element includes a plurality of discrete, spaced projections extending from at least one opposing side edge in the plane of at least one of the opposing surfaces.
The reclosable fastener can be made of only a single functional material that permits the projections on the retention element to flex during engaging and disengaging. The single functional material can be an element, a compound, a mixture, or a combination. Also, the reclosable fastener can be made integrally as one piece or as two separate pieces.


REFERENCES:
patent: 3147522 (1964-09-01), Schumm
patent: 3263292 (1966-08-01), Fekete
patent: 3514815 (1970-06-01), Evans
patent: 3518727 (1970-07-01), Eberle et al.
patent: 3857397 (1974-12-01), Brosseau
patent: 4178751 (1979-12-01), Liautaud
patent: 4581792 (1986-04-01), Spier
patent: 4677521 (1987-06-01), Frazier
patent: 4698724 (1987-10-01), Burvee
patent: 4872242 (1989-10-01), Allan
patent: 4907321 (1990-03-01), Williams
patent: 4941236 (1990-

Affiliated with

Also associated with

Rating

Strap fastener does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Strap fastener, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Strap fastener will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2512974