METHOD, APPARATUS AND MATERIALS FOR PRESERVING WOOD

Abstract

Methods and devices for protecting fence posts include placing or forming a sleeve around a lower portion of the post at ground level. The sleeve can be formed by applying a liquid plastic material around the post, and then thermally or chemically converting the liquid plastic material to a solid state, whereby the solid sleeve resists abrasion caused by the high-speed line of a string trimmer.

Claims

1. A method of treating a post having a below-ground portion and an above-ground portion, comprising: applying a plastic coating circumferentially around the post at an area of the post that during trimming is in contact with a high-speed rotating line; the plastic coating, when solidified, forming a hard, plastic protective sleeve bonded permanently to the post.

2. The method of claim 1, wherein the step of applying a plastic coating comprises one of a group consisting of spraying, dipping and painting a liquid thermoplastic material.

3. The method of claim 2, wherein the thermoplastic material is a thermoplastic polyester selected from the group consisting of high density polyethylene (HDPE) low density polyethylene (LDPE), polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene, polyester, acrylic, e.g., Lucite, cellulosic, acrylonitrile butadiene styrene (ABS), polycarbonate, acetyls, polytetrafluoroethylene (PTFE), and mixtures and variants thereof.

4. The method of claim 1, wherein the thermoplastic material is a thermoplastic nylon.

5. The method of claim 1, wherein the step of applying a plastic coating comprises one of a group consisting of spraying, dipping and painting a liquid thermosetting material.

6. The method of claim 5, wherein the liquid thermosetting material is selected from the group consisting of phenolic resin, urea-melamine, polyester and epoxy resin.

7. The method of claim 1, wherein the plastic protective sleeve has a thickness of between one and three millimeters, and has a combination of hardness, fracture toughness and tensile strength sufficient to resist abrasion from the high-speed rotating line.

8. A post comprising: an elongated wooden member having a first, above ground portion, and a second, below ground portion which is capable of being secured in a post hole to hold the elongated member vertically upwardly, the first and second portions being separated at a ground level; and a hard, plastic protective sleeve bonded to the elongated member, and circumscribing the post at an area at and extending upwardly above the ground level for a length of the first portion.

9. The post of claim 8, wherein the hard, plastic protective sleeve extends the full length of the second and covers a bottom of the second portion.

10. The post of claim 8, wherein the hard, plastic protective sleeve is made of a thermoplastic material selected from the group consisting of high density polyethylene (HDPE), low density polyethylene (LDPE), polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene, polyester, acrylic, e.g., Lucite, cellulosic, acrylonitrile butadiene styrene (ABS), polycarbonate, acetyls, polytetrafluoroethylene (PTFE), and mixtures and variants thereof.

11. The post of claim 8, wherein the hard, plastic protective sleeve is made of a thermosetting material selected from the group consisting off phenolic resin, urea-melamine, polyester and epoxy resin, and mixtures and variants thereof.

12. An apparatus for protecting a post having an upper end, a lower end adapted to mount in the ground up to a ground level, comprising: a sleeve capable of being mounted circumferential around the post at or near the ground level; the sleeve being made of a material capable of resisting abrasion caused by a high-speed line of a string trimmer.

13. The apparatus of claim 12, wherein the sleeve is made of a material selected from the group consisting of thermoplastic resin, thermosetting resin, chemically setting resin, metal and ceramic materials.

14. The apparatus of claim 12, wherein the sleeve comprises two complementary, pre-formed parts, and listening means for affixing the two parts onto the post.

15. The apparatus of claim 12 wherein the two complementary parts together form one of a circular, square and D-shaped cross section when assembled together.

16. The apparatus of claim 15, wherein the two complementary parts are formed by one of injection molding and 3-D printing.

17. A method of forming a protective sleeve for a post, comprising the steps of: collecting plastic material; heating the plastic material until it becomes liquefied; applying the liquefied material around the post at around a ground level of the post; curing the liquefied material until hardened.

18. The method of claim 17, wherein the collecting step includes collecting solid waste plastic material and placing the collected waste plastic material in a heating chamber.

19. The method of claim 17, wherein the step of applying includes one of spraying, dipping, brushing and rolling the liquefied plastic material on the post.

20. The method of claim 17, wherein the curing includes cooling the liquefied plastic material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a side elevational view of a conventional fence having a plurality of vertical posts and horizontal boards, and showing the ground in cutaway view to illustrate the below-ground portion of each post;

[0024] FIG. 2 is an enlarged side elevational view of a lower portion of one of the posts shown in FIG. 1, with a horizontal broken line showing the ground level, and two parallel horizontal lines showing a zone of exposure on the post to damage from high speed line from a string trimmer;

[0025] FIG. 3 is an enlarged side elevational view of the end portion of the post of FIG. 2, with a protective band circumscribing the post and covering the zone of exposure;

[0026] FIG. 4 is a horizontal sectional view of the end portion of the post of FIG. 3, taken along line IV-IV of FIG. 3;

[0027] FIG. 5 is an enlarged side elevational view of an alternative embodiment of the present invention, showing a boot extending from approximately the ground level of the post to, and covering, the bottom of the post;

[0028] FIG. 6 is a vertical sectional view taken along line V-V of FIG. 5;

[0029] FIG. 7 is a sequential schematic view of a method of forming a plastic sleeve, which starts with a section of PVC pipe, cutting the pipe longitudinally into two arcuate sections, placing the sections around a post, and securing the sections in place on the post;

[0030] FIG. 8 is a schematic view of another method of applying a thermoplastic material to a post, according to another embodiment of the present invention, including a heating chamber for containing scraps of plastic material;

[0031] FIG. 9 is a schematic view of the heating chamber of FIG. 8 with melted plastic material and a post being dipped in the melted plastic;

[0032] FIG. 10 is a schematic view of a post protector showing two C shaped parts that are placed around a circular section post and moved together to form a cylindrical sleeve;

[0033] FIG. 11 is a schematic view of a post protector showing a square “U” shaped part and a flat part that are placed around a square section post and moved together to form a square sleeve;

[0034] FIG. 12 is a schematic view of a post protector showing a “C” shaped part and a flat part that are placed around a D-shaped post and moved together to form a D-shaped sleeve; and

[0035] FIG. 13 is an enlarged schematic view showing a connecting means for holding two pans of a sleeve together.

DETAILED DESCRIPTION OF THE INVENTION

[0036] Referring to FIGS. 1 and 2, a fence 10 has a plurality of vertical posts 12, 14 and 16, and a plurality of horizontal boards 18, 20 and 22. The posts 12, 14 and 16 are wooden, and typically made of pressure treated pine. The posts illustrated herein are circular in cross section, but it is understood that the posts could have virtually any cross-sectional shape, including rectangular, square, compound curved, and the like. Other types of wood can be used, but since fences, particularly in farm use, can be miles long, it is important to limit the cost per post. Thus, pine is preferred due to its relatively low cost, but other conifer woods are also used, such as spruce and fir, those being particularly useful for smaller fencers, such as in cities and suburbs, due to somewhat higher cost per post. Cypress and cedar are also desirable for urban and suburban uses, but again, they tend to be even higher cost per post. Some commercially available posts are not pressure treated but can be stained or painted to add protection from rot and weather damage. In those events, the stains do not extend more than a millimeter or two into the surface, and paints reside on the surface.

[0037] The boards 18, 20 and 22 are typically made of oak, typically one inch thick by six inches wide, and most typically have three boards, but four board fences are also commonly employed. The boards are typically nailed to the posts.

[0038] The posts 12, 14 and 16 are secured in the ground by first digging a posthole. The lower end portions 12a, 14a and 16a of the posts 12, 14 and 16 are placed in the post holes and then held tightly in place by packed dirt, or in the case of urban and suburban uses with smaller numbers of posts, concrete (typically ready-mix concrete) can be poured into the hole dried to create a firm hold in the vertical upright position. The ground 24 is shown as a horizontal line extending between the posts 12, 14 and 16, and is shown cutaway to reveal the lower portions of the post being permanently set in the ground.

[0039] Other means of setting posts in the ground are available, particularly for large volumes of fencing, such as in agricultural settings where fence posts can be set for miles. Farm fencing can carry wire instead of boards, such as strands of barbed wire, or American wire, “chicken” wire, and other forms that are supported on posts. The lower end of the post can be shaped to a point and driven in the ground with post driver, as are known and available as tractor-driven implements. Some post drivers need no tapering or sharpening of the end of the post to be drive to a sufficient depth to be stable and strong.

[0040] The ground 24 absorbs rainwater and maintains a permanent moisture content that eventually will lead to rot of a wooden post. Once the lower portion of the post rots, the entire post must be replaced, at cost and inconvenience. Pressure treatment of wooden posts is designed to extend the life of a post.

[0041] In the normal course of maintenance, grass 26 and other plant growth grows under the fence boards and around the posts. It is common practice to use a string trimmer 28, sometimes called a “weed eater,” is used to trim the plant growth under the fence and around the posts. When the high-speed line of the string trimmer hits a post, over time, the surface of the post is eroded by the line. The amount of erosion, over the course of months and years of trimming, will be sufficient to cut into the post to penetrate the depth of pressure treatment fluid, thus exposing untreated wood to moisture. When this happens, the post will lose its protection from rot at around the ground level of the post, which is also a place where moisture from the ground or from rain, can wick into the post and cause rot over times.

[0042] The location of erosion of a post is illustrated in FIG. 2. The ground 24 is represented as a broken horizontal line. An area subject to erosion, abrasion or deterioration of the post surface by high-speed line from a string trimmer is shown as zone 29, which extends circumferentially around the post, slightly above and slightly below the ground level. One aspect of the present invention is to provide a protective material over the zone 29, where the protective material has sufficient hardness, and toughness, to resist erosion by the high-speed line of a string trimmer. If the post has not been set in the ground, protective material can be applied over the zone 29 so that when the post is set in the ground, some of the zone is underground and some above ground. If the post has already been set, the zone will have to be all above ground, so it will shift upward. As an in situ retrofit, the zone 29 can be covered with a sleeve of the type described herein.

[0043] As shown in FIG. 3, a band 30 is disposed over the zone 28 and is permanent y affixed thereto. The band 30 is affixed to the lower portion 14a of the post after the post is pressure treated, stained or painted. The band 30 is preferably made of a plastic material that has a hardness and/or fracture toughness, or other physical properties that render the band 30 resistant to abrasion or cutting by a rotating line of a string trimmer. As seen in FIG. 4, the band 30 completely circumscribes the circular post at the lower portion thereof. The thickness of the band 30 can range from a millimeter to several millimeters, and its length (along the post) can range from a few inches to a length that completed covers the lower portion of the post and the bottom of the post, as shown in FIGS. 5 and 6. There, a boot 32 covers the full length of the in ground portion of the post and the bottom, thus providing not only protection from abrasion by string trimmers, but also direct rot from exposure to moisture in the ground.

[0044] In a preferred embodiments, the band 30 and the boot 32 are made of a thermoplastic material, such as a thermoplastic polyester selected from the group consisting of high density polyethylene (HDPE), low density polyethylene (LDPE), polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene, polyester, acrylic, e.g., Lucite, cellulosic, acrylonitrile butadiene styrene (ABS), polycarbonate, acetyls, polytetrafluoroethylene (PTFE), and mixtures and variants thereof. Thermoplastic materials can be applied in liquid form at elevated temperatures, and when cooled they form hard, solid surfaces. In the case of the band 30, the hardness of the thermoplastic material will resist abrasion from string trimming around the posts of a fence. Many of these plastics are in widespread use for beverage containers, plastic wrappings, plastic packaging and the like, and are thus considered relatively inexpensive.

[0045] The band 30 can be retrofitted in situ by applying the plastic material around the post and then having the plastic material cool to become solid, or heated to be solid, depending on whether the plastic is thermosetting or thermoplastic. In that case, the band will start at ground level and extend upwardly by a length sufficient to shield the post from abrasion by high-speed rotating string trimmers. If the post is not yet set in the ground, the band can be applied using a variety of means, and the boot 32 can be formed by dipping the post in liquid plastic material. The post could also be coated with plastic material by other means, such as with a brush or roller. Two part epoxy resins can also be mixed and applied, and air dried

[0046] Virtually any thermoplastic material can be used, with the preferred choices depending on cost, availability and environmental factors. Nylon, or polyamides, can be used either in the monomer or polymer form. High density polyethylene (HDP) is particularly advantageous because it has a relatively low melting point and is available both in commercial quantities from plastics suppliers, and also as scrap or waste, as many bottles and packaging are made of the material and can be collected, shredded, melted and recycled as post protecting sleeves. Generally, preferred plastic materials will have a relatively low melting point so that the material can be applied in heated, liquid form to the post, by brushing, rolling, spraying, dipping or any other suitable means, and then as the liquid plastic cools, it will harden on and bond to the post.

[0047] Alternatively, a thermosetting material can be used, whereby the plastic material is applied to the post in liquid form and then heated to a temperature sufficient to harden and permanently bond to the post. Virtually any thermosetting plastic can be used, although particularly preferred materials are selected from the group consisting of phenolic resin, urea-melamine, polyester and epoxy resin.

[0048] Once heated, or cooled, the plastic material hardens and adheres to the post and provides a permanent harrier to high speed rotating lines from string trimmers. For cost and efficiency, and ease of handling, it is preferred to use thermosetting plastics that have low melting points, and thermosetting plastics that have a relatively high transition temperature (from liquid to solid state).

[0049] Other materials besides plastics can be used as barriers to abrasion. For example, cotton fabrics, similar to those used to make clothing, can be cut into bands and adhered in place using adhesives or other means. Cotton fabric, or cotton polyester blends, tends to resist abrasion from string trimmers, but suffers from being less permanent and less protective, although fabric will nonetheless be effective. Sleeves can also be made of aluminum, rubber, synthetic rubber and other elastomers if pre-formed to be attached to the post at the ground level.

[0050] Although preferred embodiments have been described whereby plastic bands are formed in situ as a retrofit after a post is set in the ground, and where the plastic bands or boots are formed on the post before setting in the ground, other embodiments include preforming plastic or metal hands or sleeves and installing them on the posts after the posts are set in the ground. FIG. 7 shows in sequence a method of making a band for protecting a circular cross-sectional post at or around the ground level of the post. First, a short length of PVC pipe 34, of an inner diameter approximately the same as the outer diameter of the post The pipe 34 is cut longitudinally into two halves, forming two arcuate sections 36 and 38. Each section is placed around the post at the zone of abrasion, at the ground level and extending upwardly from there, and then secured in place by any appropriate means, such as nails 40 or screws, pins, staples, etc. PVC piping is preferred because it is in abundant supply and relatively inexpensive. For “half post” cross-sections of a generally D-shape, one arcuate section can be couple with a flat piece of PVC to form the “D” shape and thereby encase the post at the ground level and slightly above.

[0051] In another aspect of the invention, waste plastic 42, such as from plastic beverage containers, can be shredded and placed in a heating chamber 44 whereupon a heating element 46 is activated to convert the solid waste plastic into a liquid slurry. As seen in FIG. 9, a post 48 is dipped into the heating chamber 44 to cover the lower end of the post in the liquid thermoplastic shiny 50, and subsequently cooled until the liquid hardens and becomes permanently affixed to the post. Alternatively, the liquid can be fed to a spray device, or simply brushed or rolled onto the post.

[0052] Sleeves according to the present invention can easily be made using injection molding or 3-D printing to make two complementary parts of a sleeve that can be assembled on the post in situ. Referring to FIG. 10, two C-shaped parts 52 and 54 can be injection molded or 3-D printed to be of a desired length and width to fit around a circular section post, beginning at the ground level. The two parts 52 and 54 are moved together as shown by the directional arrows and then joined either together or to the post or both. Joining means can be any conventional manner. The thickness of the parts does not have to be great, and can be on the order of a millimeter or two, or less than a millimeter. These parts are particularly suited for 3-D printing which is known to use a variety of plastic materials any number of which could be used to form the parts.

[0053] FIG. 11 shows a variation of the FIG. 10 embodiment where the post is of a square cross-sectional shape. In this case, a first part 56 has a square “U” shape, and a second part 58 has a flat, linear shape. When the two parts are positioned around the post at the ground level and moved together according to the directional arrows, a sleeve is formed around the post that protects the post from high-speed rotating string from a string trimmer.

[0054] FIG. 12 represents yet another variation for a split post having a D-shaped cross section. In this case, the sleeve is made from a C-shaped part 60 and a flat, linear part 62 that are placed around the post at the around level and moved together according to the directional arrows.

[0055] As seen in FIG. 13, end portions 64 and 66 of complementary parts can be provided with complementary fastener means, such as a snap-fitting head on end portion 64 which fits into a whole provided in end portion 66. When the two parts are brought together, the complementary fastener portions lock the two parts around the post to form the sleeve.

[0056] Commercially available two-part epoxy resins, of the type used for coating wood tabletops, can be used as coatings on the post at the area exposed to string trimming. Typically, the two part resins come with a resin and a hardener that are mixed just before use in a mixing container in a 1 to 1 ratio. The epoxy cures after application to a hard, clear finish.

[0057] Whether a resin or thermoplastic or thermosetting material, when in liquid form, the material can be augmented with a ceramic powder, such as clay or silica, to enhance the abrasive resistance, and UV resistance. Adding a ceramic powder, or any other inorganic constituents, can also reduce the cost of application, as these materials are less expensive than resins and other plastics.

[0058] Although specific embodiments of the present invention have been described, it will be understood by those of skill in the art that there are other embodiments that are equivalent to the described embodiments. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiments, but only by the scope of the appended claims.