Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TREE ROOT BARRIER COMBINATION, AND METHOD OF MANUFACTURE
Background of the Invention
Since the invention of the basic tree root control
harrier as taught by Patent No. ~,019, 279, different
inventions and approaches have been employed in exports to
reduce manufacturing costs, reduce installation labor,
minimize shipping and storage space, etc. Some of these
inventions and approaches have involved the use of
injection-molded synthetic resin barrier panels having Tee
portions at opposite ends thereof. The Tee portions of
adjacent panels are connected to each other by narrow
extruded synthetic resin connector elements, each such
element having two parallel grooves that receive and hold
the Tee portions of adjacent panels.
Injection molds are very expensive.. For large
panels, injection molds are prohibitively expensive and
impractical. Very importantly, it is not practical or
economical to make deep control barriers, or relatively
strep stair step control barriers for use on slopes, with
any injection molded panels now on the market.
Summary of the Invention
It has now been conceived to extrude continuous
lengths of control panels and then shear them into desired
lengths, which lengths can be three feet, four feet or
more without changing the size or cost of the economical
extrusion die. Because the lengths can be long, the
panels can be connected together in steeply stairsteppad
relationship and still have large overlaps and thus highly
adequate connecting strengths.
The necessity for any connector elements is
eliminated. This is because the panels are extruded not
only with root deflector elements, but with a Tee portion
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at one edge of each panel and a corresponding groove
defining element at the other edge thereof.
The panels can be shipped without any assembly, with
no chance that there will not be enough (or will be too
many) connector elements for the number of panels.
Preferably, pairs of panels are preassembled with each
other before shipment and storage, to reduce labor at the
job site and to make a factory check to be sure that the
Tees fit correctly into the grooves.
Brief Description of the Drawings
Fig. 1 is an isometric view at a hillside having
stairs thereon, and also having control barrier panels
connected to each other in stair step relationship for
prevention of root damage to the stairs, a part of the
hillside being shown as broken away to expose thy panels;
Fig. 2 is an elevation Al view taken from a point at
the right in Fig. 1, looking at the hillside with the
stairs thereon and also with trees on opposite sides of
this stairs, two narrow trenches being shown that are
adapted to receive the barriers;
Fig. 3 is an end view of one of the root control
barrier panels of the present invention, showing it
connected to the edge of one other panel;
Fig. 4 corresponds to Fig. 3 but shows three panels,
in smaller scale;
Fig. 5 is a side view of one of the root control
panels, showing the side not shown in Fig. 1; and
Fig. 6 is a diagrammatic view of the apparatus
employed to manufacture the root control panels.
Detailed Discretion of the referred Embodiment
The disclosure of U.S. Patent No. 4,019,279 is hereby
incorporated by reference herein.
Referring first to Fig. 3 of the drawings of the
present application, each panel 10 has a large body 11
that is very preferably planar. Body 11 has an inner
2~'75~?~3
surface 12 and an outer surface 13 that are parallel to
each other and coextensive. As described in the cited
patent, the body is made of a material, and has a
thickness, such that the body is impervious to penetration
by the tree roots to be controlled. Furthermore, at least
on the inner surface 12 thereof, the body is preferably
smooth.
In the best mode contemplated by the inventor, the
entire panel 10 is polyethylene and has a body that is
lo 0.080 inch thick, all surfaces being smooth. The body 11
has substantial flexibility.
The word "inner" as used in the present specification
and claims denotes the side of the panel 11 that is
relatively adjacent the tree whose roots are to be
controlled. Conversely, the word "outer" denotes the side
remote from such tree
Provided as spaced points along the inner surface 12
of body 11 are means to prevent the tree roots from
growing horizontally along the panel for more than a
predetermined distances. In the best mode contemplated by
the inventor, such means are ridges or ribs 14 having side
surfaces 16 that are at right angles to inner surface 12
and that meet such surface 12 at sharp corners. In the
best mode, thy ridges or ribs 14 are 0.080 inch thick.
Thy edge 17 of ridge 14 is spaced 0.50 inch from inner
surface 12, in the best mode.
Referring to the left portion of Fig. 3, there is
provided in integral relationship with body 11 a groove
forming (defining) element 18 that extends inwardly from
inner surface 12 at the edge of the body 11. Element 18
comprises a wall 19 that corresponds to ridge 14 in Avery
respect except that wall 19 has integrally connected
thereto at its inner edge a wall 20 that is parallel to
body 11, extending away from ridge 14.
Wall 19 is indented from the edge of the adjacent
portion of body 11, namely the left edge as viewed in Fig.
3, and wall 20 extends for a distance equal to the amount
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of indent. Accordingly, wall 20 terminates in the same
plane as the left end of body 11.
Opposed flanges 21,22 are provided at the left end of
wall 20 and at the left end of body 11, extending toward
each other and being separated from each other by a
distance slightly greater than the thickness of body 11.
There is thus formed by elements 11 and 19~22 a groove 23
(Fig. 6) of rectangular configuration (in section) as
shown, the groove 23 communicating through a slot 24 (Fig.
lo 6) with the space at the left edge of panel 10 as shown in
Fig. 3.
Proceeding next to a description of the right edge of
each panel 10 as viewed in Fig. 3, namely the panel
portion at the edge remote from groove defining portion 18
ox each panel, this is a Tee section 26 that is integral
with body 11 and is sized to be a slip fit in the above-
described groove 23 and slot 24. Stated conversely, the
groove 23 and slot 24 are sized or dimensioned so that
their walls are slip fits relative to the walls of Tee 26.
Tee 26 is perpendicular to body 11, as is the
longitudinal axis of the groove 23 as such groove is
viewed in cross section. The Tee 26 is connected
integrally to an offset section 27 that is parallel to
body 11. At the left end of offset section 27, it
collects integrally to an inclined section 28 that extends
downwardly to and is integral with the right end of body
11 as viewed in Fig. 3. In the illustrated example of the
best mode, the inclined section 28 is at a forty five
degree angle to body 11.
One edge 29 of Tee 26 lies substantially in the plane
of inner surface 12 as illustrated at the right in Fig. 3.
Tee 26 is spaced sufficiently far from inclined section 28
that the above-described flanges 21,22 may be received,
there being substantial clearance between flanges 21,22
aloud the inclined section 28 opposed thereto as illustrated
at 30 Fig. 4.
At least one side of groove-forming element 18 acts
as a ridge or rib to deflect roots downwardly, as does the
above described ridge 14. Such side is the surface of
wall 19 that is relatively adjacent ridge 14. At the
opposite side of the groove forming element 18, roots are
deflected downwardly by the outer (left in Fly. 3) surface
of flange 21 and by the corresponding outer (left) end of
well 20.
To assemble two panels 10 together, the Tee 26 is
slid longitudinally into the groove 23 (Figs. 3 and 6),
with slot I receiving section 27. This can be done until
the two adjacent panels 10 are coterminous, or may be only
partial as described subsequently. The relationships are
such that the bodies 11 of the panels are coplanar as
shown in Fig. 4.
The panels 10 may be shipped in cartons without any
preassembly with other panels, there being a substantial
number of panels stacked on top of each other in each
carton. According to the best mode contemplated by the
inventor, the panels will be shipped in preassembled
relationship, there hying two preassembled panels in each
carton and with other pairs of two preassembled panels
stacked on top of them.
By shipping the panels in preassembled relationship
as described, it is assured that each Tee 26 will fit into
its associated groove 23. Then, at the job site, in
situations where only one panel is desired (for example,
to complete a predetermined length of barrier), only one
panel is used after the other panel is disassembled from
it. It is known that any panel that can be readily
preassembled at the factory in slip-fit relationship can
be readily disassembled at the job site.
In the best mode, each panel has a dimension of one
foot from the center of groove forming element 18 at one
edge thereof to the center ox Tee 26 at the other edge
thereof. The spacing between each of such centers and the
center of ridge 14 is six inches. Thus, two preassembled
panels are approximately two feet in overall width.
d of Manufacture
Each panel 10 is formed by extrusion of hot synthetic
resin, with the groove forming element 18 and the Tee 26
integral with body 11, with the ridge 14 also integral
with body 11, all of these elements being unitary and
formed simultaneously from the same mass of hot synthetic
resin. Because each panel 10 is relatively narrow, much
less than two feet in width prior to the described
preassembly, the extrusion dies employed are relatively
inexpensive and, furthermore, tolerances relative to wall
thickness are readily maintained.
Referring to Fig. 6, an extrude is shown
schematically at 31, having dies 32 the swaps of which
corresponds generally to the shape shown in Fig. 3.
shear 33 is adapted to cut the extruded synthetic resin
into desired lengths.
A continuous length Of extruded synthetic resin is
shown at aye. After this continuous length has cooled
sufficiently, it passes through shear 33 and is cut into
individual panels 10. It is to be understood that the
process is continuous, with the shear 33 being spaced from
extrude 31 a distance appropriate for cooling of the
synthetic resin.
In the best mode, the length of each panel 10 is at
least about twice the width thereof, and is preferably
several times the width thereof. Standard lengths of the
panels are three feet and four feet for the one foot width
described above. Other length may be custom cut to any
reasonable length, such as seven feet.
Descrie~1ED_~f the Combinations
Let it be assumed, for example, that a root control
barrier approximately three feet in height is to be
installed at a new sidewalk (not shown) that has been
poured in a new tract of houses, to protect that sidewalk
from being cracked and raised by the roots of trees
planted between the sidewalk and houses reference being
made to the above-cited patent. A narrow trench (not
shown) is then made along the inner side of the sidewalk,
sufficiently deep to barely receive the three foot
barrier. Assuming that the panels have been boxed and
shipped with stacks of two-assembled panels, as stated
above, each pair of assembled panels is assembled with
other pairs thereof by sliding the Tees 29 and sections 27
into grooves 23 and slots 24. The resulting continuous
barrier is then dropped into the trench in such
orientation that ridges 14 are relatively remote from the
sidewalk and relatively adjacent the trees.
Accordingly, roots from the trees and growing toward
the sidewalk engage the inner surface 12 of the control
barrier, following which (typically) they grow
substantially horizontally until they engage one of the
elements 16 or lo, or flange 21. Then, the roots are
deflected downwardly along the ridge 14, etc., until they
reach the bottom of the tarrier, following which they turn
underneath the barrier and pass harmlessly below the
sidewalk.
It is to he understood that the trench is backfilled
with earth and/or gravel shortly after the control barrier
is disposed therein. As indicated, the depth of the
trench is such that the upper edge of the barrier is
substantially at the surface of the ground.
In Fig. 4, three barriers 10, lob and lo are shown
as assembled together. It is to be understood that these
and other barriers lo are identical to each other.
Referring next to Figs. l and 2, a concrete stairway
34 is disposed in a trench in an inclined hillside 35,
with the lower portion of the stairway beneath the surface
36 of the earth, and with the horizontal 38 and vertical
39 portions of the stairway above such surface 36.
Planted in the hillside 35 are trees 40,41 that are
located (for example) four or five feet from the sides of
the stairway 34. To protect stairway 34 from the roots of
trees 40,41 (which trees have roots that will damage
static structures such as stairway 34 in the absence of
control barriers, reference being made to the cited
patent), control barriers are provided on the sides of the
stairway 34.
Thus, narrow trenches 43 (Fig. 2) are dug in the
hillside, sufficiently deep to receive control barrier
panels 10 of the desired length. Many control panels 10
are assembled together as described above, the number of
panels often being sufficiently large that the barrier
will be adjacent the full (or any desired) length of
stairway 34.
Adjacent panels lo are assembled together in only
partially overlapping relationship, as shown in Fig. 1,
and are inserted into trenches 43 with the ridges 14
remote from the stairway 34 and relatively adjacent the
respective trees 40,41. Because of the substantial length
of the panel sections, preferably three or four feet,
there is adequate overlapping of the connected panel edge
to create strength, while still having sufficient
projection of the panels into the earth that the tree
roots will be jar below stairway 34 before passing
there beneath without causing damage thereto.
Each entire barrier may be fully assembled before
being introduced into a trench. Alternatively, only one
(or a few) panels may be introduced into a trench,
following which additional panels are assembled and
introduced while the first-assembled panels are already in
the trench.
There is backfilling of earth and/or gravel into the
trench.
In the best mode, the upper ends of the various
panels 10 are so cut off that there is about one-half inch
(continuous) height of panel above the ground surface 36,
as shown in Fig. l. Stated otherwise, the upper panel
ends are caused to be inclined correspondingly to surface
36 and slightly there above.
With the described construction, the roots grow
directly downwardly as directed by ridges 14, etc.; they
do not tend to grow perpendicularly to the inclined
surface 36 of the earth.
It is to be understood that each Tee 26 could have
other shapes, for example generally cylindrical.
lo Correspondingly, the grooves 23 (Fig. 6) would have the
same shapes. Regardless of the exact shape of the Tee or
other protuberance, there is caused to be (a) locking of
the panels so that they cannot readily pull apart, and (b)
sufficient closeness at the joints that tree roots will
not normally grow there through.
It is to be understood that the present barrier may
also be used around the roots or root ball of a tree, as
taught by the cited patent.
The foregoing detailed description is to be clearly
understood as given by way of illustration and example
only, the spirit and scope of this invention being limited
solely by the appended claims.
What is claimed is:
