U.S. patent number 3,899,805 [Application Number 05/379,147] was granted by the patent office on 1975-08-19 for indented sheet.
This patent grant is currently assigned to The Dow Chemical Company. Invention is credited to William J. McMillan.
United States Patent |
3,899,805 |
McMillan |
August 19, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Indented sheet
Abstract
Indented sheet structure is disclosed which describes a surface
of repeating hollow projections, and repeating pocket areas or
valleys, at least certain of the pocket areas having a restricted
neck opening defined by the side profile(s) of projection(s) in
adjacent positioning thereto. Like sheets are interdigitatable, in
which posture, the projections snap fit into the restricted pocket
areas of the opposite sheet, to mechanically interlock the sheets
at a multiplicity of distributed points.
Inventors: |
McMillan; William J. (Midland,
MI) |
Assignee: |
The Dow Chemical Company
(Midland, MI)
|
Family
ID: |
23496009 |
Appl.
No.: |
05/379,147 |
Filed: |
July 13, 1973 |
Current U.S.
Class: |
24/584.1; 428/33;
428/141; 24/DIG.38; 264/299; 428/99; 428/178 |
Current CPC
Class: |
E04C
2/32 (20130101); B32B 3/06 (20130101); B32B
3/28 (20130101); A44B 18/0053 (20130101); Y10T
428/24355 (20150115); Y10T 24/45152 (20150115); Y10T
428/24661 (20150115); Y10S 24/38 (20130101); B32B
2250/40 (20130101); Y10T 428/24008 (20150115) |
Current International
Class: |
A44B
18/00 (20060101); E04C 2/32 (20060101); B32b
003/30 () |
Field of
Search: |
;161/116,123,131,133,119,120,125,130,127 ;52/519 ;264/241,299 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lesmes; George F.
Assistant Examiner: Thibodeau; Paul J.
Attorney, Agent or Firm: Halldorson; Burke M.
Claims
What is claimed is:
1. An indented sheet describing at a surface portion thereof,
repeating, regularly distributed, hollow projections, a like
distribution of repeating pocket areas, at least certain of such
projections including enlarged head portions, respectively,
restricted neck regions defined in said pocket areas through means
of said enlarged heat portions, said enlarged heat portions
comprising cap elements affixed to said projections, such indented
sheet being comprised of sufficiently resilient material for
deformable, resilient passage of such enlarged heat portions by a
like-sized restricted neck region for purpose of interlocking such
surface portion to a like surface or the equivalent thereof.
2. The indented sheet of claim 1 wherein said pocket areas are of
generally inverted configuration and size to the projections.
3. The indented sheet of claim 2 wherein said projections taper
away from the plane of the sheet.
4. An indented sheet structure describing along a surface portion
thereof the combination comprising a multi-linear pattern of hollow
projections, a like pattern of repeating pocket areas, such
patterns being out of phase so that said surface portion is
interdigitable with a like surface, at least certain of said
projections having cap elements affixed thereto and defining
restricted neck regions in said pocket areas, said indented sheet
being comprised of sufficiently resilient material for deformable,
resilient passage of such cap elements by a like-sized restricted
neck region for purpose of interlocking such surface portion with a
like surface or the equivalent thereof.
5. The indented sheet of claim 4 wherein said projections taper
away from the plane of the sheet.
6. The indented sheet of claim 5 wherein said pocket areas are of
generally inverted size and configuration to said projections.
7. The indented sheet of claim 6 wherein said projections are
generally pyramidal in shape.
Description
The primary objective of this invention is to provide indented
sheet structure describing a surface which is mechanically
interlockable with a like surface.
The present invention more specifically contemplates an indented
sheet describing over at least part of a major surface thereof,
repeating hollow projections, and repeating pocket areas or
valleys, the outline of the latter being preferably of generally
inverted sizing and configuration to the projections. At least
certain of the projections include offset profiles such as in the
form of an enlarged head or head portion, which collectively or
individually define restricted neck openings in the hollows of
adjacent pocket areas. When interdigitated with a like surface, the
sheets mechanically interlock or tie together through forcible
entry of the projections into the restricted pocket areas of the
like sheet.
Further features and advantages of the invention will be more
apparent in and by the following more detailed description and
specification hereof, taken in connection with the accompanying
drawings wherein:
FIG. 1 is an isometric view illustrating a section of indented
sheet made according to the general teachings and principles of
this invention;
FIG. 2 is a fragmentary top view isolating one of the many
identical pocket areas of the indented sheet of FIG. 1, and shows
by imaginery dotted line representation, the restricted neck
opening of the isolated pocket area.
FIG. 3 is a cross sectional view of the indented sheet of FIG. 1 as
it would appear if viewed along reference line X--X, and
additionally shows a like indented sheet in mechanically
interlocked assembly with the FIG. 1 sheet;
FIG. 4 is a view like FIG. 3, only with the like sheets being
nested by reversely facing the sheets, for compactness in storing
and porting plural units thereof;
FIG. 5 is a view like FIG. 1, only showing a modified form of the
invention;
FIG. 6 is a cross sectional view through FIG. 5, taken along
reference line Y--Y thereof; and
FIGS. 7 and 8 are views like FIG. 6, respectively, only showing
still further modified forms of the invention.
Referring now to the drawing, FIG. 1 illustrates a section of
indented sheet 10 describing over a major surface portion 12
thereof, spaced apart, hollow projections 14 of pyramidal shape and
which repeat in a rectangular pattern. Each projection is capped by
an element 16 of miniature pyramidal shape, which is positioned
symmetrically over the upper tip or apex thereof, and which extends
downwardly, and terminates approximately at the mid-height of the
projection.
Cap elements 16 may be attached by gluing, heat sealing, riveting,
or the like, or may be integrally formed in molding the sheet. The
cap elements define a species of what is referred to herein as an
enlarged head or head portion 18 associated with each or at least
certain of the projections 14. The underside of each head portion
defines a circumferentially continuous offset profile 20, in the
otherwise generally uniformly tapered sidewall of each
projection.
Sheet 10 further defines numerous spaced apart pocket areas or
valleys 22 of substantially inverted configuration and sizing to
projections 14, and which repeat in a like rectangular pattern to
that of the projections. The offset profiles 20 of projections 14
collectively define a restricted neck opening or passage 24,
located at approximately mid-depth in each pocket area. The
imaginery outline of one such restricted neck opening 24 is
described by dotted lines in FIG. 2 to assist visualization
thereof.
Referring now to FIG. 3 the same illustrates a pair of identical
sheets 10 and 10' placed in interdigitated positioning with respect
to the other, that is, with the projections 14 of the sheet 10
intimately cradled in the inverted pyramidal shaped pocket areas of
sheet 10'. To obtain this position, sheets 10 and 10' are firmly
pressed together, thereby resiliently forcing the enlarged head
portions 18 of the projections past the restricted neck openings 24
of the opposite sheet. Each projection, at least in the central
area of sheet 10, is thus forcibly slipped between a quadrant of
projections on the opposite sheet 10', and vice versa, whereby
profiles 20 abut in the horizontal plane, forming a fastening point
at each corner 26 of the respective projections. The like sheets 10
and 10' are thus expediently locked together at numerous generally
regularly distributed points, thereby avoiding entirely the need
for, or only having supplemental need for extraneous rivets,
staples, adhesives, and the like, to fasten or tie together the
indented sheet structure of this invention.
Referring now to FIG. 4, sheets constructed under these teachings
may be nested, for compactness, in storage and porting. To this end
projections 14 are tapered in a manner to fit and nest into the
hollow undersides of the projections defined in a succeeding sheet
in a nested or stacked arrangement thereof. Employing a solid cap
element 16 makes it virtually impossible for the sheets to bind
together when nested. A greater outside as opposed to the inside
diameter of the projections can also be designed into the sheet
structure to discourage binding between nested sheets such as, for
example, if the sheets are to be constructed employing a hollow
enlarged head portion of the types shown in subsequent embodiments
hereof.
Referring specifically to the embodiment of FIGS. 5 and 6, a
selectively placed hollow knob 28 is located at each corner 26a of
the pyramidal shaped projections 14a of the modified sheet 10a
shown here. The knobs collectively define a pocket area 22a of
generally the same outline as that shown in FIGS. 1 and 2, wherein
the projections surrounding each such pocket area 22a describe a
restricted neck opening therein of similar character to pocket
areas 22 above. A distinction, however, is that the offset profile
20a of each projection 14a is discontinuous in form, rather than
circumferentially continuous about the projection. Functionally,
sheet 10a will interlock with an identical sheet, or any generally
like sheet such as sheet 10 supra, provided the proportions are
correct between the two sheets sought to be interlocked.
The invention is further illustrated by way of the FIG. 7
embodiment which depicts an offset profile 20b displaced downwardly
from the mid-level height of pyramidal shaped projections 14b. The
profile 20b is formed by indenting the side wall of projections 14b
as at 30 near the base of each projection. The profile 20b may be
continuous, by means of a circumferentially continuous indentation,
or discontinuous by means of a localized indentation at each or
certain of the corners 26b of projections 14b. Using the condition
of four local indentations associated with each projection, the
head portion 18b can comprise a local knob 28b selectively disposed
at each of the four corners 26b of projections 14b, respectively.
Each such knob is in linear alignment with, but spaced upwardly
from an indentation 30 at each such corner position. For reasons as
will be evident, the spacing of the knobs from the top of
projection 14b, corresponds to the spacing of the indentations from
the base of the projections. In the interlocked position between
interdigitated sheets 10b (not shown), knobs 28b are caused to snap
into the indentations 30, respectively, resulting in a mechanical
interlocking of the surfaces.
By way of yet still another illustration of the invention, in FIG.
8 the projections 14c of sheet 10c demonstrate the use of a double
enlarged head portion associated with projections 14c, such double
head portion being indicated by 18c and 18c'. Assuming again
truncated pyramidal shaped projections set in rectangular pattern,
the head portions may comprise a double interruption or undercut
ledge structure 32 and 34 formed locally at corner(s) 26c of each
projection 14c. Such double interruption, in turn, provides a
double offset profile structure 20c and 20c', and corresponding a
double restricted neck opening in the pocket areas 22c of the
sheet. In the interdigitated position of sheet 10c with a like
surface (not shown), it will be apparent that the head portions 18c
and 18c' provide a double strata or double level mechanical
fastening formation with the pocket areas of a like or generally
like surface, and vice versa.
Referring now to some of the generalities of this invention,
projections of the characteristic type intended herein may be
formed to have any practical and desired shape, so long as the same
include an offset profile capable of defining an appropriately
sized, restricted neck opening in a sufficient number of the pocket
areas, to provide a surface structure firmly attachable by
interlocking to a like surface, or the equivalent thereof. As
illustrative examples, therefore, the invention may be practiced
utilizing generally spherical or hemispherical projections,
saddle-shaped generating areas as shown in U.S. Pat. No. 3,227,598,
triangular and various other polygonal shapes which may be
truncated or otherwise, provided such projections are modified in
structure according to the teachings hereof. The projections
intended hereby may be of uniform height or tapered. Moreover,
while it is oftentimes desirable to have one side of the sheet
flat, such as the underside of sheet 10 illustrated in FIG. 1, it
is understood that the present invention can be practiced employing
sheets having raised areas on both sides thereof, by modifying at
least one side of such sheet in accordance with these teachings.
Also, while the invention has been described particularly whereby
the pattern is rectangular in nature, that is, each quadrant of
projections collectively defines or surrounds a pocket, and vice
versa, numerous other patterns may be employed so long as the
teachings herein are observed.
Preferred materials for constructing the sheet structure hereof
includes synthetic resinous thermoplastics such as, for example,
vinyl chloride, styrene, ethylene, propylene, and various like
materials as homopolymers or copolymers. Particularly impact
polystyrene would be an excellent material for use herein. The
sheets if formed from formable plastic sheet materials such as the
above or other polymeric sheet materials, can be fabricated by heat
and/or pressure forming techniques.
While certain representative embodiments and details have been
shown for the purpose of illustrating the invention, it will be
apparent to those skilled in the art that various changes and
modifications can be made therein without departing from the spirit
and scope of the invention.
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