Strip material with tab-like parts for forming fasteners

A strip of polymeric sheet material adapted to cut into lengths to form releasably engageable pieces of a fastener. The strip has a row of tab-like parts bent along bend lines out of the plane of a main part of the strip to define an opening through the strip; and the main part and tab-like parts of the strip have adjacent edge surfaces disposed at an included angle in the range of about 60 to 90 degrees with respect to the adjacent bend line so that when the tab-like parts on each of two lengths of the strip are simultaneously fully inserted through the openings in the other length with the tab-like parts projecting generally in opposite directions, the edge surfaces of the tab-like parts on one length will make frictional engagement with the edge surfaces of the main part of the strip on the other to frictionally hold the lengths in releasable engagement.

TECHNICAL FIELD 
The present invention relates to fasteners of the type having portions 
adapted for releasable engagement, and in one aspect to such fasteners in 
which both portions of the fasteners have essentially the same structure. 
DISCLOSURE OF INVENTION 
The present invention provides a simple, inexpensive, effective, easily 
made fastener that makes firm partially self aligning engagement. 
According to the present invention there is provided a fastener comprising 
first and second pieces of stiff flexible polymeric sheet material, each 
piece having a plurality of aligned, equally spaced, similarly shaped and 
oriented, generally U shaped through slits. The slits define a row of 
tab-like parts of the piece and a surrounding main part of the piece. Each 
of the tab-like parts is bent along a bend line between the ends of the 
slits defining the tab-like part to project in the same direction out of 
the plane of the main part of the piece to define an opening through the 
piece beneath the tab-like part. The bend lines of the tab-like parts are 
parallel and extend transverse of the piece, and the main part and 
tab-like parts of the piece have opposed edge surfaces adjacent the 
opposite ends of the slits disposed at an included angle in the range of 
about 60 to 90 degrees (preferably about 70 to 80 degrees or 75 degrees) 
with respect to the adjacent bend line so that when the tab-like parts on 
each of the two pieces are simultaneously fully inserted through the 
openings in the other piece with the tab-like parts projecting generally 
in opposite directions, the edge surfaces of the tabs-like parts on one 
piece will make frictional engagement with the edge surfaces of the main 
part of the piece on the other to frictionally hold the pieces in 
releasable engagement. 
The pieces can be attached to different backing layers to be releasably 
attached by the fastener, with the surfaces of the pieces opposite that 
from which the tab-like portions project against the backing layer and the 
pieces attached to the backing layers at positions spaced from the row of 
tab-like parts so that when the pieces are engaged the tab-like parts of 
one of the pieces can move to positions between the other piece and the 
backing attached to the other piece. When the backing layers are of rigid 
material, the pieces after engagement can only be disengaged by 
simultaneously sliding all of the tabs out of engagement with each other 
which takes an initial effort sufficient to overcome the frictional 
engagement between the surfaces. When the backing layers are of flexible 
material, the pieces after engagement can be disengaged either by 
simultaneouly sliding all of the tab-like portions out of engagement with 
each other which also takes an initial effort sufficient to overcome the 
frictional engagement between the surfaces, or by peeling the fastener 
portions apart one tab at a time, which peeling can facilitate separating 
the fastener portions particularly when they are used on garments, such as 
to fasten together tensioned elastic portions of garments such as 
brassieres. 
The pieces of the fastener can be cut from a strip of the stiff flexible 
polymeric material in which the tabs can be formed by passing the strip 
through a rotary die assembly.

DETAILED DESCRIPTION 
Referring now to the drawing, there is shown in FIG. 1 an elongate stiff 
flexible strip 10 of polymeric material (e.g., polypropylene in the range 
of about 0.025 to 0.051 centimeter (0.010 to 0.020 inch) thick) according 
to the present invention that is adapted to be cut into lengths to form 
releasably engageable pieces 11 of a fastener. 
The strip 10 and each piece 11 cut from the strip 10 has a plurality of 
equally spaced, aligned, similarly shaped and oriented, generally U shaped 
slits 12 along its length, which slits 12 define a row of tab-like parts 
14 of the strip 10 or piece 11, and a surrounding main part 15 of the 
strip 10 or piece 11. Each of the tab-like parts 14 is bent along a bend 
line 16 between the ends of the slit 12 defining the tab-like part 14 in 
the same direction out of the plane of the main part 15 of the strip 10 or 
piece 11 to define an opening through the strip 10 or piece 11 beneath the 
tab-like part 14, and the slits 12 and tab-like parts 14 in the strip 10 
of sheet material 10 can easily be formed by passing a strip of the sheet 
material through the nip of a pair of die wheels 13 as is illustrated in 
FIG. 2. 
The bend lines 16 of the tab-like parts 14 are parallel and extend 
transverse of the strip 10 or piece 11 of sheet material such that an 
imaginary line perpendicular to one of the bend lines 16 and bisecting the 
adjacent tab-like part 14 will bisect all of the tab-like parts 14 along 
the strip 10 or piece 11. The tab-like parts 14 and the main part 15 of 
the strip 10 or piece 11 of sheet material have adjacent edge surfaces 18 
and 20 respectively adjacent the opposite ends of the slits 12, which edge 
surfaces 18 and 20 are disposed at an included angle 22 (see FIG. 1) in 
the range of about 60 to 90 degrees and preferably in the range of about 
70 to 80 degrees or about 75 degrees with respect to the adjacent bend 
line 16. With this orientation of the edge surfaces 18 and 20, when the 
tab-like parts 14 on each of two lengths or pieces 11 of the strip 10 of 
sheet material are simultaneously fully inserted through the openings in 
the other piece 11 of sheet material with the tab-like parts 14 projecting 
generally in opposite directions (as is sequentially illustrated in FIGS. 
5-7 in which the pieces 11 being engaged are attached to backing layers 
26), the edge surfaces 18 of the tab-like parts 14 on one piece 11 will 
make frictional engagement with the edge surfaces 20 of the main part 15 
of the other piece 11 (see FIG. 8) to frictionally hold the pieces 11 in 
releasable engagement. 
Typically when the two pieces 11 are used as a fastener they are each 
attached to a different backing layer 26 as is illustrated in FIGS. 3 and 
4 for one of the pieces 11 and in FIGS. 7-9 for two of the pieces 11. The 
pieces 11 are each attached along one of the surfaces of the backing layer 
26 with the tab-like parts 14 of the piece projecting away from the 
backing layer 26, and the pieces are attached to the backing layer 26 
(e.g., by staples, sewing stitches, adhesive or fusion as by ultrasonic 
welding) at positions 30 parallel to and spaced from the sides of the row 
of tab-like parts 14 so that when the pieces 11 are engaged, the tab-like 
parts 14 of one of the pieces 11 will be positioned between the other 
piece 11 and the backing 26 attached to the other piece, as can best be 
seen in FIG. 9. 
When the backing layers 26 are of rigid material, the pieces 11 after 
engagement can only be disengaged by simultaneously sliding all of the 
tab-like parts 14 out of engagement with each other which takes an initial 
effort sufficient to overcome the frictional engagement between the 
surfaces 18 and 20. When the backing layers 26 are of flexible material, 
however, the pieces 11 after engagement can be disengaged either by 
simultaneously sliding all of the tab-like parts 14 out of engagement with 
each other (which also takes an initial effort sufficient to overcome the 
frictional engagement between the surfaces 18 and 20), or by peeling the 
pieces 11 apart from one end to disengage two tab-like parts 14 at a time 
as is illustrated in FIG. 10. Such peeling can facilitate separating the 
pieces 11 particularly when they are used on garments. 
As one preferred example, the tab-like parts 14 on a piece 11 made from 
0.015 inch thick polypropylene can have a width along the bend line 16 of 
about 0.25 inch, an angle 22 of 75 degrees, a length at right angles to 
the bend line 16 of about 3/16 inch and a tip radius opposite the bend 
line 16 of about 3/32 inch about a center spaced at a right angle from the 
bend line 16 by about 3/64 inch, and the bend lines 16 of the tab-like 
parts 14 along the piece 11 can be spaced by about 9/16 inch. 
The present invention has now been described with reference to one 
embodiment thereof. It will be apparent to those skilled in the art that 
many changes can be made in the embodiment described without departing 
from the scope of the present invention. For example, while rounded tips 
on the tab-like parts 14 are prefered for most uses, triangular tips may 
also be useful for some purposes; and other sheet materials such as metal 
or polymeric sheet material of polyester or nylon may be preferred for 
certain uses. Thus the scope of the present invention should not be 
limited to the structures described in this application, but only by 
structures described by the language of the claims and the equivalents of 
those structures.