CA1114347A - Hidden wire pole - Google Patents

Abstract

ABSTRACT
Splines which are partially inserted into longitudinal grooves in wood members, such as, outdoor light poles, are dis-closed. Conduit (e.g., electrical wires or piping) is recessed in the groove and is protected by the spline. The spline is attached to the member on only one side of the groove so that it moves with that side of the groove as the groove expands and contracts. The outer face of the spline is wider than the mouth of the groove and lies flush against the periphery of the member. Thus, even when the groove expands, the spline's outer face covers the groove and protects the wires.

Description

ë' BACKGROUND OF TIIE INVENTION

This invention relates to splines that are inserted into grooves. More particularly, this invention relates to splines that are inserted into longitudinal grooves in wooden members to hide and protect conduit recessed therein. (As used herein, the term "conduit" means any wire, pipe, tube, rope, rod,or the like, for example, electrical wire, pneumatic tubing, water pipes~ or control rods, that may be recessed in such grooves~.
It is often desirable to hide conduit inside members, such a~, poles, for aesthetic and protective reasons. For example, in geographic areas where electricity is carried by underground cables rather than by overhead lines, outdoor lamp posts sometimes are hollow, metal poles having the electrical supply lines to the fixtures inside. In many areas wooden poles are used for reasons of economy. Since it is economically impractical to drill an internal passageway for the wires in wood poles measuring twenty-five feet or more, external longitudinal grooves have been used.
The groove is cut along the outer surface of the pole and the electrical supply wires are recessed therein.
A continuing problem, however, has been how to seal the mouth of the groove (the cut in the periphery or circumference of the pole) in an aesthetically pleasing way and still protect the wires in the groove over a period of time. Complicating this pxoblem is the natural tendency of wood to expand and contract, thereby changing the size and shape of the groove. Such expan-sion and contraction are caused by changes in the woodls moisture content due to environmental conditions, particularly, the weather U.S. Patent No. 1,972,187 ~th? '18~ patent) discloses forming a longitudinal dove-tailed groove in a wooden lamp post, recessing electrical lines th~reîn and sealing the groove with two strips of wood that form a dove-tailed wedge and are held in place by screws. No adhesive is used.

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, 'P` g' U.S. Patent No. 3,360,601 (the '601 patent) discloses a ; groove in a wooden light pol~, which groove has a rectangular or triangular cross-section. The electrical supply wires to the fixture are recessed in the groove, and the rectangular groove is "closed by a suitable plugstrip," the nature of which is not disclosed. The triangular groove is sealed by reinserting the triangular strip cut out to form the groove. Adhesive is used on both internal faces of the triangular (wedge-shaped) strip to secure it in place.
' U.S. Patent No. 3,562,403 (the '403 patent) discloses forming two longitudinal grooves in a wooden utility pole and recessing electrical wires in one of the grooves. The stated purpose of the other groove is to relieve internal stress. The groove containing the wires is capped by a wood putty filler, and several layers of polyester resin and glass fiber are applied around the exterior of the pole. Optionally, the pole is wrapped with cellophane or paper before the resin-fiber mixture is applied.
Neither the '187 nor the '601 patent re~ognizes the ~' problem of groove expansion. Such expansion may result in loss of the spline inserted in the groove or decrease in the protection of the hidden wire, or both. In any event, any crack formed be-tween the spline and the side o~the groove makes the pole un-sightly. The '403 patent, while not referring specifically to groove expansion, acknowledges the related problems of checking and splitting. To overcome them, the '403 patent discloses that the poles should be encased in plasticg with optional cellophane --or paper wrapping thereunder; however, this substantially in-~ creases the cos~ and complexity o such poles.
; ' Thus, these patents fail to disclose aesthetically pleasing, easily installed, relatively inexpensive, and durable splines for protecting hidden conduit recessed in a groove in a member subject to aircumferential expansion and contraction.

, SUMM~RY

It has now been discovered that conduit recessed in a longitudinal groove in a member subject to circumferential ex-pansion can be protected from the weather in a relatively i~expen-sive, aesthetically pleasing manner. This is accomplished by employing a spline comprising an outer face portion and an in~
sertion portion. The spline i~ attached to the member on only one side of the groove.
The cross-section of the preferred spline is "T"- or mushroom-shaped. The outer face of the spline, the top of the "T", is wider than the mouth of the groove, which allows the spline to continue to cover the groove ~and hide and protect the conduit recessed therein) even when the groove becomes wicler ~ue to natural circumferential expansion of the pole.

BRIEF DESCRIPTION OF T~E DRAWINGS

In order to more fully describe the present invention, reference will be made to the accompanying drawings in which:
Figure 1 is a view of an outdoor lighting pole;
~ igure 2 is an enlarged cross-sectional view oE the pole taken along line 2-2 of Figure l;
Figure 3 is an enlarged view of a portion of Figure ~;
~ igure 4 is an exploded view of Figure 3;
Figure 5 is a cross-sectional view of the pole and spline of Figures 1 to 4 after the pole has cracked and the groove thereby widened;
Figure 6 is a cross-sectional view showing another spline of this invention;
Figure 7 is a cross-sectional view illustrating a key~ol~-shaped groove;

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Figure 8 is a cross~sectional view of a pole and spline in which the electrical wires are contained as a uni-t within the insertion piece of the spline;
Figure 9 is a cro~s sectional v:iew of a pole and a spline in which the wires are contained within a groove in the insertion plece;
Figure 10 is a cross-sec-tional view of a pole in combina-tion with an irregularly-shaped spline;
Figure 11 is a cross~sectional view of a pole and a truncated triangularly-shaped spline; and Figure 12 is a cross-sectional view of a spline inserted in a pole having a rectangular cross-s~ction.
DETAILED DESCRIPTION OF THE INVENTION
The spline of this invention may be used in any member subject to circumferential expansion and contraction having a longitudinal groo~e. Such members may be of any size or shape.
For example, if the member is an outdoor lighting pole, its cross-; sectional shape may be rectangular, circular, or triangular, the length may be from just a few feet up to 25 feet or more, and the cross-sectional area may be from a few square inches to several sguare feet or more. Usually, the member is an outdoor lighting pole having a circular cross~sectional area.
The long~tudinal groove in the member is as long as circumstances require. For example, the groove in an outdoor lamp post haviny a fixture at its top would require a groove running the length of the pole. The depth and width of the groove must be sufficient to accommodate the insertion piece of -the spline~ Addi-tionally, if the conduit to be recessed in the groove is not part of the insertion piece of the spline, then the groove must be large enough ko contain it as well as the insertion piece.
Generally, the groo~e will be from 0.5 to 5 inches deep, prefer-ably from 0.5 to 2 inches deep. The width may range from O.l to

2 inches, preferably from O.l to 1 inches.

Techniques for making the groove are well-known. ~ny wood-working tool that can cut a groove along the pole may be used. For example, a standard circular saw blade,with the cutting edge appropriately modified, mounted in a portable or jig-type p~wer head could be used.
The spline is roughly "T"-shaped in cross-section. It can also be described as mushroom-shaped in cross-section. The spline may be viewed as comprising two sections. The outer face o the spline is the section that is visible after the spline has been installed. The outer face is analogous to the top of the "T"
or the cap of the mushroom. The insertion piece of the spline is the portion that is inserted into the groove in the longitudinal member~ It is analogous to the base of the "T" or the stem of the mushroom.
The spline may be manufactured using any known techni~ue, such as, extrusion. The two portions of the spline may be made separately and later joined or the spline may be made as a unit~
The spline may be made in standard lengths or in long segments that could, for example, be wound on a spool.
~0 The spline may be composed of any material that is chemioally inert, has good outdoor aging characteristics, excellent electrical properties (for example, high resistivity), good abra- , sion resistance, and is hard, tough, light weight, and noninflam-able.Generally, a plastic is used but other materials (e,g., metals or wood) may be used dependi~g on the particular service.
Preferably, the spline is compDsea of polyvinylchloride and is ~lexible. Cellulose b~utyrate may also b~ used~
The outer face of the spline is usually from 0.01 to 0.5 inches thick, preferably from 0.01 to 0.25 inches thick. The outer face need not be of uniform thickness~ For example, the ends of the ou~er ~ace may be of one thickn~ss and gradual:Ly increase to a maximum thickness at the point where the outer face ; meets the insertion piece9 The outer Eace may be of any sh~pe. It is desirable, however, that the shape not prevent the outer face oE the spline from lying against the pèriphery of the member. This is for aesthetic reasons as well as to prevent water ~rain, sleet, and so forth) from entering the groove. Thus, if the spline is being inserted into a member having a circular cross-section, the outer face of the spline will generally have approximately the same curvature as the member so that the outer face may lie flush against the memberO If the spline is being used on a flat surface 10. of a member, the outer face will generally also be flat, for the same reason.
The width of the outer face must be greater than the width of the grooveO It is a feature of this invention that as the sides of the groove move farther apart, due to the natural circumerential movement of the member, the mouth of the groove remains hidden by the outer face of the spline. Thus, the spline-and-pole unit will remain aesthetically pleasing and the conduit . ~
will be protected even khough the groove enlarges. In contrast, the splines of the prior. a~ do not cover the mouth of the groove. ~:
Thus, watar can enter the mouth of the groove and promoke cracking.
The insertion piece may be o any shape so long as it possesses a suitable surface for bonding to one of the faces of the groove, assuming adhesive is to be.used to attach the in-sertion piece to the member. In that case, if the groove is sub-stantially triangular in cross-sec~ion, the insertion piece will also have at least one side forming a corresponding angle with the outer face, and usually a triangular insertion piece ~ill be used. If the groove i5 substantially rectangular, the i~sertion piece will also be generally rectangular. Naturally, the spline ; 30 need not touch the back wall of the groove or conform to the shape of the back portion of khe groove. For example, a rectangular insertion piec~ can be used with a keyhole-shaped groove. The insertion piece need not be solid and, in fact, the conduit may becompletely encased within the insertion piece.
Generally, the insertion piece meets the outer face mid-way between the two edges of the outer face. Howeverl the inser-tion piece may also meet the outer face at other points~ For example, the insertion piece could meet the outer face near one of the tw~ edges of the outer face, in which case the cross-section o~ the spline would resemble an "L".
A~other essential feature of the present invention is that the spline is attached to the member on only one side of the groove. If the spline were attached to the member on both sides of the groove, circ'umferential expansion of the member and con-sequential widening of the groove would cause failure of the spline, of the means for attaching the spline to the member, or of both. For example, if adhesive were used on both sides of the ~' ~ groove and the groove widened, the spllne might not remain ad-'~ hered to the same side of the groove along the entire length of the member. In that case, the spline would appear to snake along the member. It is also possible that the spline could fall out 2'0 of the member. By attaching the spline to the member~on only ~ne of the two sides of the groove, the possibility of such tensive forces is eliminated.
' Any means may be used to attach the spline to the member and the point of attachment may vary. E'or exa~ple, nails, staples, or the like may be used without ~dhesive to attach the outer face to the periphery of the member. A'lternatively, adhesive may be usea between the insertion piece a~d the corresponding inner surface of the groove and one side of the outer face nailed to the ; periphery of the member. Another possibility is that adhesive alon~ is used, between the insertion piece and the inner surface of the groove, between the member and the outer face of the spline, or in both places. Preferably, the attaching means is aclhesive and ': ' ' ' ~

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3~`7 it is used both between the member and the outer face and between the insertion piece and the inner surface of the groove. In any case, it is essential that the spline be attached to the member on only one side of groove.
The procedure for installing the spline is as follows.
First the groove is formed using any suitable technique. Then, if the conduit is separate from the spline, the conduit is placed into the groove. Adhesive, staples, or the like may be used to secure the conduit in the groove. If adhesive is to be used to attach the spline to the member, the adhesive is applied to the member on one side of the groove or to the spline or to both and `
the insertion piece is inserted into the groove. If means such as staples are to be used, the spline is inserted and the outer face stapled to the member.
If adhesive is used it should be weather-resistant.
Desirably, the adhesive should be able to withstand direct weathering for approximately 7 years or more. Because the mem~er may expand and contract at or near the side of the groove to which the spline is adhered, the adhesive must possess sufficient dry elasticity to prevent such expansion and contraction from breaking that ad-hesive bond. Thus, desirably, the adhesive should have 300% to 500% shrink and stretch capability. Also, the adhesive should cure sufficiently in a relatively short period of time to allow handling. Such curing should not be affected by compounds normally present in the member. For a wood member these compounds include water, wood oils and resins, and preservatives. Additionally, the compounds present should have minimal effect on the properties of the cured adhesive.
A preferred group of adhesives is tha-t disclosed in United States Patent No. 3,372,083. These adhesives are made from an isocyanate-terminated prepolymer and an isocyanate adduct of an unmodified tar. The 3~7 prepolymer is a polyurethane-type made from polyols and isocyanates having at least two reactive isocyanato yroups. The adduct is made by reacting a bituminous substance with an isocyanate having one or more reactive isocyanato groups. Vulchem 116 adhesive, manufactured by Mameco International of Cleveland, Ohio ~nd which, according to Mameco, is covered by the aforesaid patent, ha,s been found es-pecially useful.
Turning now to the Figures, Fig. 1 depicts an outdoor street light 10 employing the present invention. The street light 10 comprises wooden member 12, spline 30, and fixture 14.
Figure 2 is a cross-sectional view of wooden member 12 `
and spline 30 taken along line 2-2 of Fig. 1. A longitucLinal, rectangular shaped groove in wooden member 12 is defined by left-side wall 16, ri~ht-side wall 18, and rear wall 20. Wire 4~ is recessed in the groove and is hidden from view by spline 10, which has the preferred "T"-shaped cross-section.
In Figure 3, an enlarged view of the area surrounding spline 30, it is seen that adhesive layer 22 bonds wire 40 and spline 30 to the member. The outer face of the spline is bonded to the periphery of the member and the insertion piece and wire are bonded to the left inner surface of the groove. Thus, the spline is attached to the member on the left side of the groove by means of 'IL" shaped glue line 22. Spline 30 is fully inserted into the gxoove so that the outer face lies against the periphery (or cir-cumference) of member 12.
Figure 4 is an exploded view of Fig. 3. Wire 40 actually :: -contains three wires 42. Insertion piece 34 and outer face 32 are seen to comprise spline 30.

Figure 5 is a view of Fig. 2 later in time after a ~ 30 longitudinal crack has developed in w~oden member 12. Right ; gxoove wall 18 has moved away from wire 40 and insertion piece 34.

~ However, this crack is not visible from the outside because outer .

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3~ ~' face 32 o~ spline 30 is wide enough to hide the crack, Further-more, outer face 32 has remained in close contact with the periphery of wooden member 12, thus pro~ecting wire 40 from environmental factors, such as, the weather.
In Figure 6, walls 116, 118, and 120 define a longitudinal, rectangular groove in member 112. A layer of adhesive 122 secures wire 140 and spline 130 to the member on the left side of the groo~e. Spline 130 comprises outer face 132 and insertion piece 134. In this case, spline 130 has been fabricated such that in-sertion piece 134 meets outer face 132 near one edge of the outer face. Such an asymmetrical spline may be used, for example, when it is anticipated that the groove expansion will occur primarily on one side of the groove. Here, expansion is expected primarily on the side of wall 118.
In Figure 7, member 212 contains a keyhole-shaped yroove defined by left wall 216, right wall 218, and rear circular wall 220. Wire 240 is recessed in the circular portion 220 of the groove. Spline 230 is attached to the member on the left side of *he groove by means of nails 236. Outer face 232 lies against the perimeter of member 212.
In Figure 8, walls 316, 318, and 320 define a rectangular groove in member 312. Wires 342 are contained within insertion piece 334 of spline 330~ Adhesive layer 322 bonds insertion piece 334 to wall 316 of the groove and outer face 332 lies against the periphery of member 312. There is no adhesive be-tween the outer face of the spline and the memberO
In Figure 9, walls 416, 418, and 420 define a rectangular groove in member 412. Spline 430 compris~s outer face 432 and insertion piece 434. The insertion piec~ is open at the back and ~30 wires 442 have been recessed thexein. A layer of adhesive 422 bonds the spline to the member on the left side of the groove.

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In Fi~ure 10, walls 516, 518, and 520 define a rectangular groove in member 512. Spline 530 comprises outer face 532 and insertion piece 534. The as~mmetrical insertion piece 534 com-prises a triangular portion and a rectangular portion and is bonded to wall 516 by glue line 522. Wires 542 lie in the space between insertion piece 534 and right wall 518.
In Figure 11, walls 616 and 618 define a triangular groove in member 612. Wires 6g2 are recessed at the back of the groove and are held in place by spline 630. Spline 630 comprises outer face 632 and insertion piece 634, the latter having a truncated triangular ~or trapezoidal) shape. A layer of adhesive 622 bonds insertion piece 634 to wall 616. Note that the left side of insertion piece 634 conforms to wall 616. It is not necessary that the right side of insertion piece 634 conform to wall 618 because they are not being adhesively joined.
In Figure 12, member 712 having a rectangular cross-section is shown. Walls 716, 718, and 720 define a groove into which wires 742 and spline 730 are inserted. Adhesive layer i22 bonds insertion piece 734 to wall 716. Outer face~732 of spline 730 is flat rather than curved so that it can lie flush against the outer wall of the member. Wires 742 are not glued or other-wise bonded in place, but are held in place by the spline.
It should be understood that -the various embodiments shown in the figures are fox illustrative purposes only. Other modifications and variations will be apparent to those skilled in the art and the claims are intended to cover all such modifications and variations.

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Claims (23)

WE CLAIM:

1. In combination, (a) an elongate member having a longitu-dinal groove therein, said member being subject to circumferential expansion and said groove having conduit recessed therein;
(b) a spline comprising an outer face and an insertion piece, said outer face being wider than the groove is at the periphery of the elongate member and said insertion piece being inserted into said groove; and (c) means attaching the spline to the member on only one side of the groove.

2. The combination of claim 1 wherein the spline is of polyvinylchloride or cellulose butyrate.

3. The combination of claim 1 wherein the elongate member is an outdoor lamp post.

4. In combination, (a) an elongate member having a longitu-dinal groove therein, said member being subject to circumferential expansion and said groove having conduit recessed therein;
(b) a spline comprising an outer face and an insertion piece, said outer face being wider than the groove is at the periphery of the elongate member and said insertion piece being inserted into said groove; and (c) a layer of adhesive adhering the spline to the member on only one side of the groove.

5. The combination of claim 4 wherein the elongate member is substantially rectangular or circular in cross-section.

6. The combination of claim 4 wherein the spline is of polyvinylchloride or cellulose butyrate.

7. The combination of claim 4 wherein the adhesive is made from an isocyanate-terminated prepolymer and an isocyanate adduct of an unmodified tar.

8. The combination of claim 4 wherein the conduit is located within the insertion piece.

9. The combination of claim 4 wherein the spline is generally "T"-shaped in cross-section.

10. The combination of claim 4 wherein the elongate member is an outdoor lamp post.

11. In combination, (a) an elongate wooden member having a longitudinal groove therein and said groove having conduit recessed therein;

(b) a spline comprising an outer face and an insertion piece, said outer face being wider than the groove is at the periphery of the wooden member and said insertion piece being inserted into said groove; and (c) a layer of adhesive adhering the spline to the member on only one side of the groove.

12. The combination of claim 11 wherein the spline is of polyvinylchloride or cellulose butyrate.

13. The combination of claim 11 wherein the adhesive is made from an isocyanate-terminated prepolymer and an isocyanate adduct of an unmodified tar.

14. The combination of claim 11 wherein the conduit is located within the insertion piece.

15. The combination of claim 11 wherein the spline is generally "T"-shaped in cross-section.

16. The combination of claim 11 wherein the elongate member is substantially circular in cross-section and the groove is substantially rectangular in cross-section.

17. The combination of claim 16 wherein an electrical wire is recessed in the groove and the spline is generally "T"-shaped in cross-section.

18. A method for hiding and protecting conduit recessed in a longitudinal groove in an elongate member subject to circumferential expansion by means of a spline comprising an outer face and an insertion piece, comprising (a) forming the groove;
(b) placing conduit into the groove; and (c) inserting the insertion piece into the groove and attaching the spline to the member on only one side of the groove.

19. The method of claim 18 wherein the member is of wood.

20. The method of claim 18 wherein adhesive is used to attach the spline to the member.

21. The method of claim 18 wherein the spline is of polyvinylchloride or cellulose butyrate.

22. The method of claim 18 wherein the conduit is electrical wire.

23. The method of claim 18 wherein the spline is generally "T"-shaped in cross-section.