Patent Application
20250180159
Piles are vertical posts or poles driven into the ground or attached to other objects. Piles may be formed of wood, concrete, steel or other materials. Commonly, piles are used to stabilize or hold other objects. In a typical application, piles are driven into the ground and a floating dock or similar floating object is held horizontally in place by the pile. The floating dock of other floating object comprises a pile guide. The pile extends through an internal area of the pile guide that allows vertical movement of the dock of other floating object relative to the pile, but retards horizontal movement.
Pile guides in common use have inadequate service lives. Most pile guides in common use are formed of metal. Metal pile guides are not sufficiently resistant to environmental factors such as weather and sunlight. Particularly in salt water applications, corrosion of metals, even galvanized metals, leads to replacement of the pile guides.
As the pile guide moves upwardly and downwardly relative to the pile, friction is present between the pile and the pile guide. Concrete piles in particular result in abrasion and wear of the pile guide. In some cases, the pile guide may comprise wheels to reduce friction, but wheels require bearings that do not have a long service life in wet applications, and particularly in salt water.
Steel piles may result in less frictional interaction with the pile guide than concrete piles or wood piles, but steel piles are subject to corrosion. Some steel piles may be coated to resist corrosion, but the coating wears off due to weather and abrasion with the pile guide, exposing steel surfaces to weather and salt water, and the resulting corrosion.
Abrasion and wear of pile guides is exacerbated by inaccurate placement of piles, especially piles that are driven or otherwise placed in the ground. The spacing of piles may not match the position of pile guides on a floating dock or floating object with precision. Piles may not be positioned exactly vertically. These factors mean that piles may place more force, and therefore more, or even complete, loading one side of the pile guide, resulting in more rapid wear of one side of the pile guide. However, the solution is frequently to replace the entire pile guide at substantial trouble and expense.
There is a need for a low friction pile guide that is resistant to environmental degradation, and also has easily replaceable components.
The present invention is a pile guide having a body formed of thermoplastic polymer, such as polyethylene. The body has an internal area constructed and arranged to receive and retain a pile in the internal area of the body. A plurality of spaced apart inserts formed of thermoplastic polymer, such as polyethylene, are attached to the internal area of the body and extend outwardly from the internal area of the body so that contact of the pile is with the inserts. The inserts are replaceable so that as the inserts wear due to frictional engagement with the pile, worn inserts may be replaced without replacement of the other components of the pile guide. The inserts are preferred to be formed of a corrosion resistant, low friction, chemical resistant, high impact and low moisture absorbing thermoplastic material.
The body 2 of the invention as shown in this embodiment is circular and annular. The body has an internal circumference 8 through which a pile traverses as the pile guide moves vertically in use. The body has a plurality of slots 10 formed in the top surface of the body for receiving the inserts. It is preferred that the body is formed as a continuous member having no gaps.
In this embodiment, the inserts 4 are formed as an inverted “L” shape. The shorter leg of the L meets the longer leg at 90° angle. The shorter leg is inserted into a slot 10 of the body 2 and fastened to the body. The inserts are preferred to be attached to the body by a fastener 12 that is removable, such as a threaded fastener, which allows each insert to be replaced as necessary due to wear or other defects in the insert. The inserts extend outwardly from the internal circumference of the body so that they are positioned between the pile and the body.
In this embodiment, there are eight (8) inserts 4 that are spaced apart at equal intervals. As shown in
In a preferred embodiment, the inserts 4 are formed of ultra-high molecular weight polyethylene (UHMW). UHMW is preferred because it has high sliding capabilities and is abrasion resistant. UHMW provides reduced friction and reduced wear due to abrasion as compared to other materials and other thermoplastics. UHMW is also corrosion resistant, has high impact strength and low water absorption compared to other materials and thermoplastics.
However, UHMW is difficult to form into shapes, such as by machining, compared to other thermoplastics. Therefore, the use of multiple small inserts 4 of a simple geometric shape is preferred over larger inserts of more complex geometry. The eight (8) inserts shown in the embodiments depicted in
The body 2 is formed of a thermoplastic such as polyethylene. One material that may be used is high density polyethylene (HDPE). HDPE is easy to machine, easy to form and easy to weld, while providing high strength to density. HDPE has excellent impact resistant and is corrosion proof. HDPE is less expensive than UHMW. HDPE provides lower material cost for the relatively larger body than a body formed of UHMW. (UHMW would be difficult to form as the body.) The HDPE body can be welded to the attachment plate 6. The combination of UHMW and a thermoplastic such as HDPE provides a pile guide that is strong and is corrosion and weather resistant in hostile environments such as marine applications, while providing abrasion resistance and low friction when sliding against a pile. The UHMW inserts 4 can be easily and cost effectively replaced, without the necessity of removing and replacing an entire pile guide or removing the pile guide body from the pile.
The pile guide is therefore formed of two materials that are preferred to be durable and corrosion resistant, such as thermoplastics. The body 2 is formed of a first thermoplastic, and the inserts 4 are formed of a second thermoplastic that has lower frictional characteristics than the first thermoplastic; that is, the second thermoplastic has higher sliding characteristics than the first thermoplastic.
In an embodiment of the invention, attachment plate 6 is formed of the same thermoplastic as the first thermoplastic of the body 2. While the drawings show the attachment plate as a flat plate, the attachment plate is not limited to any particular structure, but may be formed as required by the particular application.
The body 202 and inserts 204 as shown in
The attachment plate 206 as shown in
The attachment plate 206 as shown in
In another embodiment of the clips 218, the clips are Z-shaped. A first end of the Z-shaped clip is attached the body, such as by a fastener. The opposite end of the Z-shaped clip is inserted into a slot 220 formed in the inserts. The middle section of the Z-shaped clip meets the ends at a right angle.
Clips may be used in geometric configurations of the body other than the rectangular body to provide additional stabilization of the inserts, especially where the pile guide is large and/or the inserts are exposed to substantial force. The clips should not extend across the sides of the inserts further than necessary so that the useful life of the inserts is not greatly reduced as the inserts wear. The slots 220 as shown in
In yet another embodiment of the invention, the inserts may be formed in multiple parts that cover the entire or substantially the internal circumference of the body. There are not fewer than two (2) inserts. For example, the inserts may be formed as semi-circles that collectively form a circle that covers the entire internal circumference of the body. The inserts could comprise more than two (2) inserts, but not less than two, since the inserts must be easily removable, and because one (1) insert is likely to be subject to more wear than the remaining inserts. The body and inserts may be formed of materials as indicated herein, and the inserts attached to the body so as to be removable. Threaded fasteners may be used to attach the inserts to the top of the body as shown in the drawings.
In each embodiment, an insert or inserts attached to one side of the body may extend further into the internal area of the body than inserts on another side of the internal area of the body. The installer may observe that a pile has an orientation that will bias the pile toward one side of the pile guide. To accommodate for this bias, an insert or inserts may extend further out from the body, such as by being thicker, providing more thermoplastic material on one part of the internal area of the body to compensate the anticipated increase in wear.
