CA2075538A1 - Tree root barrier combination, and method of manufacture - Google Patents

Abstract

ABSTRACT

A control barrier for preventing damage by tree roots to sidewalks and other structures is disclosed. Unlike some previous techniques for providing such barriers the invention provides by extrusion continuous lengths of control panels which are then sheared into desired lengths, which lengths can be three feet, four feet or more without changing the size or cost of the econom-ical extrusion die. Because the lengths can be long, the panels can be connected together in steeply stairstepped relationship and still have large overlaps and thus highly adequate connecting strengths. The necessity for any connector elements is elimina-ted. This is because the panels are extruded not only with root deflector elements, but with a Tee portion 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.

Description

aye 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 2 2~5~7tJ.~,~
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 ~7~J._b3~

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:

Claims (15)

1. A control barrier for controlling tree roots to prevent them from damaging sidewalks and other static structures, said control barrier comprising:
(a) a first control barrier panel having a thin flexible synthetic resin body that is sufficiently thick to prevent its penetration by tree roots, said body having edges that are parallel to each other, one of said edges having a continuous groove defining element formed thereon and which defines a continuous groove, the other of said edges having a continuous protuberant portion formed thereon, (b) a second control barrier panel having a thin flexible synthetic resin body that is sufficiently thick to prevent its penetration by tree roots, said body of said second panel having edges that are parallel to each other, one of said edges of said second panel having a continuous groove defining element formed thereon and which defines a continuous groove, the other of said edges of said second panel having a continuous protuberant portion formed thereon, (c) a third control barrier panel having a thin flexible synthetic resin body that is sufficiently thick to prevent its penetration by tree roots, said body of said third panel having edges that are parallel to each other, one of said edges of said third panel having a continuous groove defining element formed thereon and which defines a continuous groove, the other of said edges of said third panel having a continuous protuberant portion formed thereon, said protuberant portion of said second panel being shaped and sized to fit into said groove in said first panel in such relationship that insertion of said protuberant portion of said second panel into said groove in said first panel connects said first and second panels together at their edges, said protuberant portion of said third panel being shaped and sized to fit into said groove of said second panel in such relationship that insertion of said protuberant portion of said third panel into said groove in said second panel connects said third and second panels together at their edges, and (d) root deflector means provided on said first, second and third panels.

2. The invention as claimed in claim 1, in which said first, second, and third panels are identical to each other.

3. The invention as claimed in claim 1, in which each of said groove defining elements of each of said panels is integral with said body of such panel, and in which each of said protuberant portions of each of said panels is integral with said body of such panel.

4. The invention as claimed in claim 3, in which said body of each of said panels, said groove defining element of each panel, and said protuberant portion of each panel were formed simultaneously from a mass of hot synthetic resin.

5. The invention as claimed in claim 3, in which said body of each of said panels, said groove defining element ox each panel, and said protuberant portion of each panel were extruded simultaneously from a mass of hot synthetic resin.

6. The invention as claimed in claim 3, in which said body of each of said panels, said groove dunning element of each panel, and said protuberant portion of each panel, and said root deflector means of each panel, were extruded simultaneously from a mass of hot synthetic resin.

7. The invention as claimed in claim 1, in which said first, second and third panels are assembled with each other, said protuberant portion of said third panel being disposed in said groove in said second panel, said protuberant portion of said second panel being disposed in said groove in said first panel.

8. The invention as claimed in claim 7, in which said assembled panels are embedded in the ground in substantially vertical positions, with said groove defining means, said protuberant portions and said root deflector means disposed substantially vertically, in which a sidewalk or other static structure is disposed in the ground on one side of said assembled panels, and in which a tree is disposed in the ground on the other side of said assembled panels, said tree being of a type which, in the absence of said assembled panels, tends to extend roots that would damage said sidewalk or other static structure, said assembled panels being so oriented relative to said tree that roots from said tree that grow into contact with said panels are typically deflected downwardly by said bodies and by said root deflector means.

9. The invention as claimed in claim 8, in which said root deflector means are ridges on the side of said bodies relatively adjacent said tree, said ridges being at a steep angle relative to said bodies.

10. The invention as claimed in claim 1, in which each of said panels has a dimension, in the direction of said protuberant portions and of said groove defining elements and said root deflector means, that is at least twice as large as the dimension of each panel in a direction at a right angle to said protuberant portion and said groove defining means and said root defector means.

11. The invention as claimed in claim 1, in which each of said panels has a dimension, in the direction of said protuberant portions and of said groove defining elements and said root defector means/ that is at least several times as large as the dimension of each panel in a direction at a right angle to said protuberant portion and said groove defining means and said root defector means.

12. The invention as claimed in claim 1, in which the distance between said edges is less than two feet, and in which the dimension of said panel parallel to said edges is at least three feet.

13. The invention as claimed in claim 8, in which said ground is a hill, in which said static structure is a concrete stairway on said hill, and in which said panels are overlapped in stair step relationship.

14. A control barrier for controlling tree roots to prevent them from damaging sidewalks and other static structures, said control barrier comprising:
(a) a first control barrier panel having a thin flexible synthetic resin body that is sufficiently thick to prevent its penetration by tree roots, said body having edges that are parallel to each other, one of said edges having a continuous groove defining element formed thereon and which defines a continuous groove, the other of said edges having a continuous protuberant portion formed thereon, (b) a second control barrier panel having a thin flexible synthetic resin body that is sufficiently thick to prevent its penetration by tree roots, said body of said second panel having edges that are parallel to each other, one of said edges of said second panel having a continuous groove defining element formed thereon and which defines a continuous groove, the other of said edges of said second panel having a continuous protuberant portion formed thereon, (c) a third control barrier panel having a thin flexible synthetic resin body that is sufficiently thick to prevent its penetration by tree roots, said body of said third panel having edges that are parallel to each other, one of said edges of said third panel having a continuous groove defining element formed thereon and which defines a continuous groove, the other of said edges of said third panel having a continuous protuberant portion formed thereon, said protuberant portion of said second panel briny shaped and sized to fit into said groove in said first panel in such relationship that sliding of said protuberant portion ox said second panel longitudinally into said groove in said first panel locks said first and second panels together at their edges, and in such relationship that when thus locked said first and second panels are generally in the same plane as each other, said protuberant portion of said third panel being shaped and sized to fit into said groove of said second panel in such relationship that sliding of said protuberant portion of said third panel longitudinally into said groove in said second panel locks said third and second panels together at their edges, and in such relationship that when thus locked said third and second panels are generally in the same plane as each other, and (d) root deflector means provided on said first, second and third panels, each root deflector means on each panel extending parallel to said edges of such panel.

15. A method of protecting static structures from tree roots, which comprises:
(a) continuously extruding hot synthetic resin to form a continuous flexible panel having side edges one of which is a continuous protuberance and the other of which defines a continuous groove, said groove being sized and shaped to receive and hold said protuberance when said protuberance is slid therealong in a direction longitudinal to said panel, (b) shearing said continuous panel into a multiplicity of discrete identical panels, (c) assembling said discrete panels into a continuous panel, by means of said protuberances and grooves, whereby said side edges are perpendicular to the orientation they had during said extrusion step, (d) digging a trench in the earth between a tree and a sidewalk or other static structure, and (e) disposing said assembled continuous panel in said trench to prevent damage to said static structure by roots from said tree.