U.S. patent number 3,634,915 [Application Number 05/028,410] was granted by the patent office on 1972-01-18 for zipper tooth.
Invention is credited to Herbert Alberts.
United States Patent |
3,634,915 |
Alberts |
January 18, 1972 |
ZIPPER TOOTH
Abstract
A zipper tooth has a body portion with an opening at one end for
connection to a tape to form a zipper stringer of a slide fastener.
At the other end of the body portion is an engaging head. Just
behind the engaging head are a pair of grooves, one on each side of
the body portion. The grooves are contoured to accommodate portions
of the engaging heads of other similar zipper teeth. At each end of
each of the grooves are outwardly extending tapered projections.
The projections are rolled over to provide endwalls for the grooves
so that a cavity is formed for locking accepting portions of
engaging heads of other zipper teeth.
Inventors: |
Alberts; Herbert (312 Sao
Paulo, BR) |
Family
ID: |
21843302 |
Appl.
No.: |
05/028,410 |
Filed: |
April 14, 1970 |
Current U.S.
Class: |
24/402 |
Current CPC
Class: |
A44B
19/06 (20130101); Y10T 24/2538 (20150115) |
Current International
Class: |
A44B
19/02 (20060101); A44B 19/06 (20060101); A44b
019/04 () |
Field of
Search: |
;24/205.13 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Gelak; Bernard A.
Claims
What is claimed is:
1. A zipper tooth for inclusion in a zipper by connection to the
tape thereof, said zipper tooth comprising a body portion having
top, bottom and first and second side surfaces, means at one end of
said body portion and positioned intermediate said top and bottom
surfaces for engaging the tape of the zipper stringer, an engaging
head at the other end of said body portion, said engaging head
being symmetrical about a plane intermediate said side surfaces and
parallel thereto, first and second grooves in said first and second
side surfaces, each of said grooves being similarly contoured to
receive the engaging head of other zipper teeth, and four tapered
projections, each of said tapered projections extending outwardly
from a different one of the peripheral edges of said grooves, to
provide endwalls at the ends of said grooves whereby cavities are
provided for lockingly accommodating portions of the engaging heads
of other zipper teeth, each of said tapered projections having a
first surface adjacent a groove, said first surface being
substantially planar and parallel to said top and bottom surfaces,
and having a second surface displaced from said groove, said second
surface being slanted with respect to said top and bottom
surfaces.
2. The zipper tooth of claim 1 wherein said engaging head includes
two ears transversely extending in opposite directions.
3. The zipper tooth of claim 2 wherein each of said ears has a back
surface which is perpendicular to said plane and defines one of the
walls of one of said grooves, and a front surface in a plane
oblique to said plane.
4. The zipper tooth of claim 2 wherein each of said ears has flat
top and bottom surfaces for stopping against the first surfaces of
said tapered projections.
Description
This invention pertains to slide fasteners or zippers and, more
particularly, to zipper teeth for connection to tapes or the like
to form the stringers of slide fasteners.
In recent years, there has been a trend in the slide fastener
industry to make zippers from plastic. In many cases, the zippers
are made by the injection molding of thermoplastic materials. In
the teeth of such zippers there must be provided
asymmetrical-shaped members or the teeth require further
operations, such as slitting, after the molding to provide positive
locking of the teeth after closure of the zippers. In other words,
the positive locking prevents lateral displacements between
adjacently meshed zipper teeth. Heretofore, such zipper teeth,
because of their construction, had points of weakness which
subjected the teeth to easy breakage.
Furthermore, the molds for such zipper teeth often required
cam-operated mold parts that are reciprocatingly driven. If such
molds were not used then the resulting molded product required
further mechanical deformations, such as cutting, punching or
stamping. In any event, all of these possible solutions required
complicated equipment which is extremely costly. Even neglecting
the cost of the equipment, the production rates of such pieces is
relatively slow. These two factors greatly increase the cost of the
final product.
It is, accordingly, an object of the invention to provide improved
zipper teeth which while being simple to manufacture provide the
positive intertooth locking heretofore obtained by complex molding
and forming operations.
It is another object of the invention to provide improved zipper
teeth which are molded from simple two-part molds and which require
no further punching or cutting to provide recesses for locking the
meshed teeth against lateral movements.
Briefly, the invention contemplates a zipper tooth for part of a
zipper stringer wherein the zipper tooth is connected to a zipper
tape. The zipper tooth comprises a body portion having means at one
end for engaging the tape of the zipper stringer. At the other end
of the body portion is an engaging head. Behind the engaging head
there is at least one groove which is contoured to receive a
portion of the engaging head of another zipper tooth. At least one
tapered projection extends outward from the body portion in the
region of a portion of the periphery of one end of the groove.
The zipper tooth is molded in this manner and, thereafter, the
tapered projection is rolled over to provide an endwall for the
groove so that an engaging head received by the groove is stopped
from moving in the direction of the rolled-over tapered projection,
out of the groove.
Other objects, the features and advantages of the invention will be
apparent from the following detailed description of the invention
when read with the accompanying drawings, wherein:
FIG. 1 shows a perspective view of a zipper tooth in accordance
with the invention;
FIG. 2 shows a side view of the zipper tooth of FIG. 1 (the other
side view, not shown, is identical);
FIG. 3 shows a bottom view of the zipper tooth taken along the line
3--3 of FIG. 2 (the top view, not shown, is identical);
FIG. 4 is a cross-sectional view of a plurality of meshed zipper
teeth similar to the zipper tooth of FIG. 1; and
FIG. 5 is a cross-sectional view taken along the line 5--5 of FIG.
2.
The zipper tooth 10, according to the invention, comprises a body
portion 12 and an engaging head 14 fixed to one end of and integral
with the body portion 12. Body portion 12 has a top surface 16, a
bottom surface 18 and side surfaces 20 and 22.
Passing through body portion 12 at the other end thereof is a
generally elliptically cross-sectioned passageway 24 which opens to
the rear end of body portion 12. In a finished zipper stringer the
beaded tape (not shown) is tightly fitted in passageway 24.
Immediately behind engaging head 14 are a pair of identical
parallel grooves 26 and 28. Groove 26 is in side surface 20 and
groove 28 in side surface 22. Grooves 26 and 28 are so contoured to
accept the ears 30 and 32 of the engaging heads of identical other
zipper teeth. (See FIG. 4.)
If the zipper teeth 10 were merely fabricated as described up to
this point it is apparent that any relative movement of the teeth
in an out of the plane of FIG. 4 (hereinafter called lateral
movement) would result in the separating of the meshed
stringers.
In order to prevent this lateral movement and to positively lock
the ears of the engaging heads in grooves, endwalls are formed at
the ends of the grooves so that cavities are defined.
The endwalls are formed in the following manner. When the zipper
tooth is molded, it is molded with tapered projections 52, 54, 56
and 58 shown in dotted lines in FIGS. 1 and 5. A typical tapered
projection 50 (FIG. 5) extends outward (upward) from top surface 16
along a portion of the periphery of groove 26. Projection 50 has
one surface 60 which is coplanar with groove 16 and perpendicular
to top surface 16 and another inclined surface 62 making an acute
angle with surface 60.
I have discovered that, with such a tapered shape, if a compressive
force is applied to the heat softened projection, the projection
will fold over in a direction away from the inclined surface. Such
rolling over of the dotted line projection 50 is shown by solid
projection 50' in FIG. 5 with surface 62 becoming surface 62'.
In FIGS. 1 to 3, the tapered projections 50', 52', 56' and 54' are
shown in their rolled-over final position. As is apparent from
these Figures, the rolled-over projections 50' and 54' provide
endwalls for groove 26 to provide a cavity which lockingly accepts
an ear of an engaging head. These endwalls prevent any relative
lateral displacement of adjacently meshed zipper teeth.
While only one embodiment of the invention has been shown and
described in detail, there will now be obvious to those skilled in
the art, many modifications and variations satisfying many or all
of the objects of the invention as defined by the appended
claims.
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