U.S. patent number 3,751,852 [Application Number 05/115,013] was granted by the patent office on 1973-08-14 for plastic planter flat.
This patent grant is currently assigned to Fabri-Kal Corporation. Invention is credited to Gerald A. Schrepper.
United States Patent |
3,751,852 |
Schrepper |
August 14, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
PLASTIC PLANTER FLAT
Abstract
A compartmented tray thermoformed from a sheet of thermoplastic
material and having at least two rows of compartments, adjacent
compartments in each row being separated by cross ribs. A
reinforcing rib extends continuously from one end of the tray to
the opposite end thereof joining the pair of adjacent rows. Each of
the cross ribs and the reinforcing rib have a substantially
inverted U-shaped cross section and the height of the reinforcing
rib is greater than the height of the cross ribs to provide a
reinforcing structure transverse to each of the cross ribs to
strengthen the tray against bending. The cross ribs in one row of
compartments are offset with respect to the cross ribs of an
adjacent row of compartments but in each row all of said cross ribs
are modularly spaced.
Inventors: |
Schrepper; Gerald A.
(Kalamazoo, MI) |
Assignee: |
Fabri-Kal Corporation
(Kalamazoo, MI)
|
Family
ID: |
22358815 |
Appl.
No.: |
05/115,013 |
Filed: |
February 12, 1971 |
Current U.S.
Class: |
47/87; 229/406;
220/23.6 |
Current CPC
Class: |
A01G
9/028 (20130101) |
Current International
Class: |
A01G
9/02 (20060101); A01g 009/02 () |
Field of
Search: |
;47/34.13,37
;220/23.6,23.2,21,22,72,97D ;229/2.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pulfrey; Robert E.
Assistant Examiner: Rader; R. T.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A compartmented tray thermoformed from a sheet of thermoplastic
material, comprising:
a pair of upstanding side walls and a pair of upstanding end walls
and a bottom wall;
an upstanding reinforcing rib integrally molded in said bottom wall
and extending continously from one end of the tray to the opposite
end thereof to define a pair of adjacent longitudinally extending
rows on opposite sides of said reinforcing rib;
asymmetrical stiffening means disposed in said rows on opposite
sides of said reinforcing rib, said asymmetrical stiffening means
consisting of a plurality of upstanding first cross ribs integrally
molded into said bottom wall for separating one of said rows into
adjacent compartments and a plurality of upstanding second cross
ribs integrally molded into said bottom wall for separating the
other of said rows into adjacent compartments,
said second cross ribs being longitudinally spaced from and
nonaligned with said first cross ribs in said one row to thereby
define said asymmetrical stiffening means to effect a strengthening
of said tray against bending along a line of the cross ribs.
2. A compartmented tray according to claim 1, including also a
plurality of longitudinally extending rows each having a plurality
of elongated, longitudinally spaced and upstanding first ribs in
the bottom of said tray lower in height than and parallel to said
reinforcing rib for effecting further longitudinal stiffening of
said tray.
3. The compartmented tray defined in claim 2, including also a
plurality of longitudinally aligned, laterally spaced second ribs
in the bottom of said tray extending parallel to said reinforcing
rib and extending continuously between and perpendicular to said
cross ribs and drain openings extending through said bottom
arranged along said second ribs, said openings being of a diameter
greater than the width of said second ribs.
4. The compartmented tray defined in claim 3, wherein the upper
contour on each of said cross ribs is arcuate in shape.
5. The compartmented tray defined in claim 4, wherein the portion
of each of said cross ribs adjacent the reinforcing rib is lower
than the opposite end thereof adjacent one of said side walls.
6. The compartmented tray defined in claim 3, wherein the upper
contour on each of said cross ribs is concavely arcuate.
7. The compartmented tray defined in claim 1, including means
defining a plurality of stacking lugs on said tray to prevent a
plurality of stacked trays from sticking together.
8. A compartmented tray thermoformed from a sheet of thermoplastic
material, comprising:
a pair of upstanding side walls and a pair of upstanding end walls
and a bottom wall;
an upstanding reinforcing rib integrally molded in said bottom wall
and extending continously from one end of the tray to the opposite
end thereof to define a pair of adjacent longitudinally extending
rows on opposite sides of said reinforcing rib;
asymmetrical stiffening means disposed in said rows on opposite
sides of said reinforcing rib, said asymmetrical stiffening means
consisting of a plurality of longitudinally spaced and upstanding
first cross ribs integrally molded in said bottom wall and
extending perpendicularly to and between a side wall of said tray
and one side of said reinforcing rib to separate one of said two
rows into compartments and a plurality of longitudinally spaced and
upstanding second cross ribs integrally molded in said bottom wall
and extending perpendicularly to and between the other side wall of
said tray and the other side of said reinforcing rib to separate
the other of said two rows into compartments, each of said second
cross ribs being longitudinally spaced from and nonaligned with
said first cross ribs in said one row to thereby define said
asymmetrical stiffening means, said longitudinal spacing between
said first and second cross ribs being equal to one half the
spacing between said cross ribs in said first and second rows so
that said symmetrical first and second cross ribs will effect a
strengthening of said tray against bending along a line of the
cross ribs.
9. A compartmented tray thermoformed from a sheet of thermoplastic
material, comprising:
a pair of upstanding side walls and a pair of upstanding end walls
and a bottom wall;
an upstanding reinforcing rib integrally molded in said bottom wall
and extending continously from one end of the tray to the opposite
end thereof to define a pair of adjacent longitudinally extending
rows on opposite sides of said reinforcing rib;
asymmetrical stiffening means disposed in said rows on opposite
sides of said reinforcing rib, said asymmetrical stiffening means
consisting of a plurality of longitudinally spaced and upstanding
first cross ribs integrally molded in said bottom wall and
extending perpendicularly to and between a side wall of said tray
and one side of said reinforcing rib to separate one of said two
rows into compartments and a plurality of longitudinally spaced and
upstanding second cross ribs integrally molded in said bottom wall
and extending perpendicularly to and between the other side wall of
said tray and the other side of said reinforcing rib to separate
the other of said two rows into compartments, each of said second
cross ribs being longitudinally space from and nonaligned with said
first cross ribs in said one row to thereby define said
asymmetrical stiffening means, the spacing between an end wall of
said tray and the nearest cross rib in at least one of said first
and second rows being equal to a single spacing unit, said single
spacing unit being also equal to said longitudinal spacing between
any pair of said longitudinally spaced first and second cross ribs
so that said asymmetrical first and second cross ribs will effect a
stengthening of said tray against bending along a line of said
cross ribs.
10. The compartmented tray according to claim 9, wherein the number
of said first cross ribs in said one row is one greater than the
number of said second cross ribs in said other row.
11. The compartmented tray according to claim 10, wherein the
number of said first cross ribs equals three and the number of said
second cross ribs equals two.
Description
FIELD OF THE INVENTION
This invention relates to a compartmented tray and, more
particularly, relates to a thermoformed thermoplastic planter flat
having a plurality of compartments therein defining a modular
system for receiving a planter liner having a shape adapted to be
received in the compartmented tray.
BACKGROUND OF THE INVENTION
Thermoformed trays have been proposed for many uses, but in general
have been restricted to carrying relatively light loads. This
problem arises from the fact that in elongated compartmented trays
wherein the compartments are in lateral alignment, there is only a
small resistance to bending along the line of compartment
separators. This lateral alignment, however, follows in the prior
art from the necessity of the tray being able to receive a liner
having compartments of equal size and spacing.
One design for meeting this problem is set forth in Smith U.S. Pat.
No. 3,502,241 which discloses a compartmented tray having two rows
of compartments with adjacent compartments in each row being
separated by cross members which are colinear with the cross
members which separate the corresponding adjacent compartments in
the other row. As acknowledged in this patent, the colinear
relationship between the cross members presents a situation of only
nominal resistance against bending along the line of the respective
colinear cross members. As a result, it is necessary to provide a
reinforcing feature which here comprises a longitudinal reinforcing
member which joins the adjacent rows and has a height greater than
the height of the cross members. Nevertheless, although the problem
has been lessened by the provision of the central reinforcing rib,
the existence of the colinear cross members still presents a
bending problem along the line of the aligned cross members. This
bending limits the usefulness of this type of tray and has in the
prior art provided a continuing problem.
I have discovered that the compartmented tray may be adequately and
very simply strengthened by a relocation of the cross members,
namely by offsetting same with respect to each other in adjacent
rows while also spacing same in a modular manner to enable the tray
to continue to receive liners having evenly spaced compartments. I
have also discovered that the tray can be further strengthened by
making the upper laterally extending contour of the cross members
arcuate between ends thereof that are at different elevations to
thereby resist a bending moment applied to the tray along an axis
parallel to the longitudinal axis of the tray. Accordingly, the
objects of this invention include:
1. To provide a compartmented thermoformed tray incorporating an
improved strengthening feature to prevent bending of the tray along
a line transverse to the central reinforcing rib.
2. To provide a modular arrangement in the spacing between the
cross ribs in each row to accommodate the reception of a liner tray
having compartments of equal size and spacing.
3. To provide a compartmented tray which may be manufactured by
vacuum-forming, and/or pressure forming, a sheet of thermoplastic
material to the desired shape.
4. To provide a compartmented tray which may be manufactured by
presently known devices.
Other objects and purposes of this invention will be apparent to
persons acquainted with compartmented trays of this general type
upon reading the following specification and inspecting the
accompanying drawings, in which:
FIG. 1 is a perspective view of the compartmented tray embodying
the invention and a liner member which is adapted to be received in
the compartmented tray construction;
FIG. 2 is a top view of the compartmented tray;
FIG. 3 is a sectional view taken along the line III--III of FIG.
2;
FIG. 4 is a sectional view taken along the line IV--IV of FIG.
2;
FIG. 5 is an enlarged fragmentary sectional view of the encircled
portion A in FIG. 4; and
FIG. 6 is an enlarged fragmentary sectional view taken along the
line VI--VI of FIG. 2.
Certain terminology will be used in the following description for
convenience in reference only and will not be limiting. The words
"up," "down," "right" and "left" will designate directions in the
drawings to which reference is made. The words "in" and "out" will
refer to directions toward and away from, respectively, the
geometric center of the device and designated parts thereof. Such
terminology will include derivatives and words of similar
import.
SUMMARY OF THE INVENTION
A compartmented tray is thermoformed from a sheet of thermoplastic
material and has at least two rows of compartments, adjacent
compartments in each row being separated by cross ribs. A
reinforcing member extends continuously from one end of the tray to
the opposite end thereof joining the pair of adjacent rows. Each of
the cross ribs and the reinforcing rib have a substantially
inverted U-shaped cross section and the height of the reinforcing
member is greater than the height of the cross ribs to provide a
reinforcing structure transverse to each of the cross ribs to
strengthen the tray against bending. The cross ribs in adjacent
rows are offset from each other but arranged modularly in each row
in order to receive a compartmented liner wherein the compartments
are of equal size and spacing,
DETAILED DESCRIPTION
Referring now to the drawings in detail, a tray 10 (FIG. 1 and 2)
is thermoformed from a sheet of thermoplastic material and
comprises upstanding endwalls 11 and 13, sidewalls 12 and 14, and a
bottom wall 16, all integrally connected together. The upper edge
of each of the walls 11, 12, 13 and 14 is curled over as at 17
(FIG. 4). The curled upper edge 17 of each upstanding wall serves
to strengthen the upper edges thereof and to resist a bending
and/or flexing of the tray.
A longitudinal reinforcing rib 18 extends longitudinally of the
tray and is parallel with and is positioned, in this embodiment,
centrally between the upstanding sidewalls 12 and 14. The
reinforcing rib 18 has an inverted U-shaped cross section and is
integrally connected to the upstanding end walls 11 and 13 and the
bottom wall 16. The height of the reinforcing rib 18 is less than
the height of the upstanding walls 11, 12, 13 and 14.
The bottom wall 16 comprises a plurality of laterally spaced rows
21 of upstanding ribs 22 integrally formed therewith. The
upstanding ribs 22 extend longitudinally of the tray 10 parallel
with the reinforcing rib 18. Each rib 22 is longitudinally spaced
from an adjacent rib 22 to define a gap 23 (FIGS. 2 and 3). In this
particular embodiment, each rib 22 has an inverted U-shaped cross
section and is rounded at the longitudinal ends as at 24.
The bottom wall 16 also comprises a plurality of rows of laterally
spaced and parallel ridges 26 on opposite sides of the reinforcing
rib 18 which extend between and parallel to the ribs 22, the
reinforcing rib 18 and the sidewalls 12 and 14. A plurality of
longitudinally spaced holes 27 are provided in the ridges 26, which
holes 27 are greater in diameter than the width of each of the
ridges 26. In this particular embodiment, the ridges 26 are closely
adjacent the upstanding sidewalls 12 and 14 and the reinforcing rib
18. An intermediate ridge 28 is provided on the bottom wall 16
which extends parallel between the pairs of rows of ridges 26 on
opposite sides of the central reinforcing rib 18.
A plurality of cross ribs 31 are provided on one side of the
reinforcing rib 18, which cross ribs 31 extend perpendicular to the
sidewall 12 and the reinforcing rib 18 to define a row 19 of
compartments divided by said cross ribs. Each cross rib 31 has an
inverted U-shaped cross section and is integrally connected to the
bottom wall 16, the reinforcing rib 18, the ribs 21 and the ridges
26 and 28. The height of the cross rib 31 adjacent the central
reinforcing rib 18 is less than the height of the cenral
reinforcing rib 18 to rigidify the container where the cross ribs
are joined to the central reinforcing rib to prevent a bending on a
transverse axis to the central reinforcing rib. The upper contour
32 of the cross rib 31 is generally arcuate and curves upwardly
(FIG. 4) so that the end of the cross rib 31 adjacent the
upstanding sidewall 14 is approximately equal in height to the
height of the central reinforcing rib 18. The arcuate portion
serves to prevent a hinging action about the line of the cross ribs
31.
A plurality of further cross ribs 34 are provided on the other side
of the reinforcing rib 18, which cross ribs 34 extend perpendicular
to the upstanding sidewall 14 and the reinforcing rib 18 and define
a second row 21 of compartments divided by the cross ribs 34. The
cross ribs 34, like the cross ribs 31, have an inverted U-shaped
cross section and are integrally connected to the bottom wall 16,
the ribs 21, the ridges 26 and 28, the upstanding sidewall 14 and
the central rib 18. The height of the cross rib 34 adjacent the
central rib 18 is less than the height of the reinforcing rib. The
upper contour 36 of the cross rib 34 is generally arcuate and
curves upwardly (FIG. 4) so that the end of the cross rib 34
adjacent the upstanding sidewall 14 is approximately equal in
height to the height of the reinforcing rib 18. The arcuate portion
serves to prevent a hinging action about the line of the cross ribs
34.
The foregoing construction of the cross ribs 31 and 34 also serve
to prevent a bending of the tray about an axis parallel to the
central reinforcing rib 18.
The cross ribs 31 and 3 in the compartmented tray 10 are offset
from each other as illustrated in FIG. 2 and spaced from each other
and from the end walls 11 and 13 distances which are multiples of a
single spacing unit. Thus, in this embodiment, the distances from
the end walls 11 and 13 to the respectively adjacent cross ribs 31
are both equal to the single spacing unit and the spacing of the
remaining ribs 31 is twice said single spacing. Further, in this
embodiment the spacing between the cross ribs 34, and between the
end ones thereof and the end walls 11 and 13, is also twice said
single spacing unit. Further, in this embodiment, the longitudinal
spacing between a pair of cross ribs 31 is equal to twice the
longitudinal spacing between a cross rib 31 in row 19 and the next
adjacent cross rib 34 in row 21. Since the cross ribs 31 and 34 are
not aligned with one another, the strength of the tray is
substantially improved due to the lack of a continuous cross rib
extending laterally across the width of the tray.
The longitudinal spacing between the ribs 31 and 34 thus defines a
modular arrangement. The compartment 37 (FIG. 2), for example,
defined by the upstanding wall 12, the central reinforcing rib 18
and two of the cross ribs 31 is of a size to receive two
compartments of a compartmented liner, described below, the
compartment defined between either end wall 11 or 13 and the
nearest cross rib 31 will receive one compartment of such
liner.
The liner 38 comprises a receptacle 39 having a peripheral flange
40 is divided into a plurality of compartments 41 aligned in rows
42 and 43 and each are preferably interconnected to the other by a
perforable connection 44 to permit each compartment 41 to be
separated one at a time or in groups from the remainder of the
liner 38. Each compartment 41 is adpated to receive seedlings 45
therein and each compartment 41 has a plurality of openings 46 in
the bottom wall thereof to permit the seedlings to be watered with
the excess water draining through the openings 46.
When the liner is inserted into the compartmented tray 10, as
illustrated in dotted lines in FIG. 3, the liner will be supported
by its flange 40 on the upper curled over edge 17 on the tray 10.
The liner 38 is flexible enough so that it will sag and the bottoms
of each of the compartments will rest on the ribs 22. A pair of
compartments 41 in one of the rows 42 or 43 of the liner 38 will be
located between the cross ribs 31 and 34 and single ones of such
compartments will be located between the end walls 11 and 13 and
the respectively adjacent cross ribs 31. Thus, the longitudinal
spacing between one cross rib 31 in one row and the next adjacent
cross rib 34 in the adjacent row is equal to the width of one of
the compartments 41 in the liner 38. Thus, the modular arrangement
of the cross ribs 31 and 34 and their spacing from the end walls 11
and 13 is adapted to cooperate with the spacing arrangement between
the compartments 41 of the liner 38.
Further, the cross ribs 31 and 34 serve to prevent a shifting of
the liner 38 relative to the tray 10, such as might occur if the
liner 38 is inadvertently snagged by a piece of equipment which
places the seedlings 45 and/or the dirt in the compartments 41.
More specifically, the longitudinally facing sides 48 (FIG. 3) of
each of the compartments 41 engage the longitudinally facing sides
of the cross ribs 31 or 34. As a result, sufficient of such
compartments are restrained by the cross ribs 31 or 34 to deter a
relative shifting between the liner j38 and the tray 10.
The spacing or gap 23 between the longitudinal ends of the ribs 22
permits the water which drips out through the holes 46 in liner 38
to be able to drain out of the tray 10 through any of the holes 27.
The ridges 26 having the holes 27 therein serve to define a path
for the drained water after the water leaves the tray 10. That is,
the bottom surface of the ridge 27 is lifted off the support
surface as at 47 in FIG. 5 so that the water can flow toward the
longitudinal ends of the tray or the nearest cross rib 31 or
34.
A plurality of stacking lugs 35 (FIGS. 2 and 6) are provided in
each of the four corners of the tray 10 and serve to prevent a
plurality of stacked trays from sticking together. Each stacking
lug comprises a pocket 51 in each of the four corners of the
adjoining sidewalls 11, 12, 13 and 14 to define a projection 52
which will rest on the next adjacent edge portion 17 on the next
adjacent tray 10. Similarly, a plurality of stacking lugs 49 are
provided in each of the corners of each of the compartments 41 of
the liner 38 and serve to prevent a plurality of stacked liners
from sticking together.
While the tray 10 has been illustrated with two rows 19 and 21 of
compartments, any desired number of rows can be employed, with a
reinforcing rib joining each pair of adjacent rows. In each row,
however, the number of cross ribs 31 or 34 will be unequal to the
number of cross ribs in the next adjacent row. In the particular
embodiment illustrated in FIG. 2, the number of cross ribs 31
exceeds the number of cross ribs 34.
Although a particular preferred embodiment of the invention has
been disclosed in detail for illustrative purposes, it will be
recognized that variations or modifications of the disclosed
apparatus, including the rearrangement of parts, lie within the
scope of the present invention.
* * * * *