Metal tools and implements – making – Blank or process – Cutlery
Reexamination Certificate
1999-06-18
2001-05-29
Peterson, Kenneth E. (Department: 3724)
Metal tools and implements, making
Blank or process
Cutlery
C076SDIG008, C030S346580, C030S346530
Reexamination Certificate
active
06237444
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to a disposable, single-edged safety razor blade of the type having a cutting edge and an opposing, blunt non-cutting edge and, more particularly, to an improved safety razor blade tool having a “rubberized,” slip-resistant protective cover over the non-cutting edge to allow for a more comfortable and secure grip of the safety razor blade when used as a cutting tool.
Referring to
FIG. 1
, there is shown a disposable, single-edge safety razor blade
15
that was originally developed for shaving. The blade
15
is substantially rectangular and has a lengthwise cutting edge
16
and an opposing non-cutting edge
17
. A thin metal strip
18
, coextensive with the length of the blade is wrapped around the non-cutting edge
17
and crimped in place to serve as a protective cover for the non-cutting edge. This strip
18
also provides a thicker profile for easier handling and holding of the blade
15
by a user.
While single-edge disposable razor blades have long been supplanted for shaving purposes by more modern razor blades and disposable razors, such blades have found wide-spread use as general purpose, low cost, disposable, light-duty cutting tools. For example, people, use the safety razor blades for scraping paint from glass and for cutting sheets of paper and other materials.
While blade holders of various designs providing a good grip for cutting for the type of blade shown in
FIG. 1
are known and available, most users prefer to use the blade without a holder by grasping the metal strip
18
during use. Accordingly, it would be desirable to provide the disposable, single-edged razor blade of the type shown in
FIG. 1
with a protective cover for the non-cutting edge that provides a more secure grip to improve the effectiveness of the blade as a general purpose cutting tool.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a safety razor blade tool comprising a substantially rectangular, single-edged safety razor blade having a cutting edge and an opposing non-cutting edge and a thermoplastic protective cover fixedly attached to the non-cutting edge. The protective cover is substantially coextensive with the length of the non-cutting edge of the blade and has a resilient, slip-resistant surface. The protective cover comprises two substantially identical, complimentary cover parts. Each cover part comprises an injection-molded substantially rigid inner layer of thermoplastic material and a rubberized outer layer covering the rigid inner layer, the outer layer comprising a compatible, injection-molded thermoplastic rubber.
In a preferred embodiment, the thermoplastic rigid inner layer comprises a polyolefin and the rubberized outer layer comprises ethylene-propylene-diene monomer rubber. In this embodiment, most preferably, the polyolefin is polypropylene. In another preferred embodiment, the thermoplastic rigid inner layer comprises a polyvinyl chloride and the rubberized outer layer comprises a hydrogenated adduct of a styrene-butadiene block copolymer with maleic anhydride.
The safety razor blade tool according to the present invention may be produced by providing a substantially rectangular, single-edged safety razor blade having a cutting edge and an opposing non-cutting edge. The substantially rigid thermoplastic is then injected in a viscous state into an injection-molding device. Next, the substantially rigid thermoplastic in a viscous state is allowed to solidify. After the substantially rigid thermoplastic has solidified, a thermoplastic rubber in a viscous state is injected into the injection-molding device, the thermoplastic rubber being compatible with the substantially rigid thermoplastic. Next, a first cover part comprising an inner layer and an outer layer is formed, the inner layer comprising the substantially rigid thermoplastic and the outer layer comprising the compatible thermoplastic rubber covering the inner layer. A second cover part is formed either sequentially with or, preferably, simultaneously with the first cover part. The second cover part is substantially identical to and complementary with the first cover. Finally, the first cover part and the second part are fixedly attached to the non-cutting edge of the razor safety blade.
In a preferred embodiment of the method of producing the safety razor blade tool, the attaching step comprises joining the cover parts of the safety razor blade tool by ultrasonic welding.
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Bic Corporation
Choi Stephen
Pennie & Edmonds LLP
Peterson Kenneth E.
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