Abstract:
A deck plank is co-extruded from an extrusion die which receives molten plastics materials supplied from three separate plastic extruders to provide the plank with opposite sides having different colors. Preferably, the base plank is extruded from a lower cost material such as reground scrap polyvinylchloride (PVC), and thin PVC cap layers are co-extruded on opposite sides of the base plank in different colors. Opposite edges of each plank have longitudinally extending grooves for receiving hidden fasteners in the form of screws extending through short flat tie pieces or a continuous sealing tie strip projecting into the opposing grooves of adjacent planks.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to a deck plank of extruded plastics material and its assembly onto a supporting structure, for example, of the general type disclosed in U.S. Pat. No. 6,301,842 which issued to the Assignee of the present invention. As disclosed in this patent, it is known to extrude deck planks from a plastics material such as polyvinylchloride (PVC) and wherein the base plank is extruded of a less expensive reground or scrap plastics material or PVC, and the top surface is formed by a thin co-extruded capstock layer of more expensive or virgin PVC. The capstock layer provides the top surface with a predetermined durable color and a top pattern surface, for example, a knurl surface with a raised diamond pattern. It has also been found desirable to provide a deck plank which is reversible and with opposite sides having different colors. For example, one side of the deck plank may be gray or off white, and the opposite side may have a color of light brown or a color and texture similar to a treated wood deck plank. It is further desirable to provide for simple and quick assembly of extruded deck planks with hidden fasteners and sometimes with a water-tight seal between adjacent planks so that rain water runs off the ends of the assembled planks.  
         SUMMARY OF THE INVENTION  
         [0002]    The present invention is directed to an improved deck plank of extruded plastics material and which provides all of the desirable features mentioned above. In addition, the deck plank of the invention provides a high strength/weight ratio and substantially reduces a dealers inventory of deck planks since each deck plank is offered with side surfaces in two different colors and may be simply reversed by the customer for selecting between the colors. It is to be understood that the term “deck plank” as used herein includes any plank which is used for supporting people or articles, such as a plank used for making boat docks or for making platforms of all types.  
           [0003]    In general, an extruded deck plank constructed in accordance with the invention includes parallel spaced side walls integrally connected by spaced transverse walls which are preferably perpendicular to the side walls. The transverse walls forming opposite edge walls of the deck plank define longitudinally extending slots or grooves within the center of the plank so that the plank is symmetrical about a reference plane extending through the grooves. The side walls of the deck plank are co-extruded with a capstock layer of plastics materials which are supplied from separate extruders to provide the opposite side walls with side surfaces of different colors, thereby permitting the customer or consumer to select between the two colors for the color of the top surface of the deck.  
           [0004]    Preferably, the base deck plank is extruded of a less expensive reground scrap material, and the different colored cap layers are extruded of the virgin plastics material with the cap layers extending along the opposite edge walls to the center grooves. When the deck planks are assembled on a supporting frame structure, such as parallel spaced joists, short key or tie pieces or strips project into the opposing grooves of adjacent planks and provide a spacer between the planks. The tie pieces or strips are extruded with flexible fins which provide for a water-tight seal between adjacent deck planks.  
           [0005]    Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a perspective view of a deck plank constructed in accordance with the invention and with a middle portion removed to illustrate an indefinite length;  
         [0007]    [0007]FIG. 2 is an end view of the deck plank shown in FIG. 1;  
         [0008]    [0008]FIG. 3 is a fragmentary section illustrating a plurality of the deck planks shown in FIG. 1 installed on a supporting structure; and  
         [0009]    [0009]FIG. 4 is an enlarged fragmentary section of the deck plank shown in FIGS.  1 - 3  and with a tie piece or strip exploded therefrom. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0010]    [0010]FIGS. 1 and 2 illustrate a deck plank  10  which is co-extruded from three different plastics materials, such as PVC materials, and includes a pair of side walls  12  integrally connected by perpendicular transverse walls including intermediate webs or walls  14  and opposite edge walls  16 . Each of the edge walls  16  includes a longitudinally extending U-shaped portion  18  defining a corresponding slot or groove  21 . The grooves  21  are within the center portions of the edge walls  16  so that the plank  10  is symmetrical about a center reference plane P extending through the center of the grooves  21 . As shown in FIGS. 1 and 2, each of the side walls  12  is extruded with parallel spaced traction grooves  23  which are located in longitudinal alignment with the interconnecting intermediate connecting walls  14 . The traction grooves  23  also eliminate the appearance of any sink lines in the side walls  12  due to the intermediate walls  14 .  
         [0011]    Referring to FIG. 4, each of the side walls  12  and the connecting portions of the edge walls  16  down to the grooves  21  have corresponding base layers  26  and  27  which are integrally extruded with the intermediate walls  14  and the U-shaped portions  18  to form a base plank. The base layers  26  and  27  are co-extruded with thinner capstock or cap layers  32  and  34 , respectively, and the cap layers  32  and  34  are supplied from separate corresponding extruders which extrude plastics materials or PVC of different colors so that the outer surfaces of the opposite side walls  12  have different colors. For example, cap layers for one side wall  12  and adjoining edge walls  16  may be gray or off white, and the cap layers for the opposite side wall  12  and adjoining edge walls  34  may be tan or clay or a color resembling treated wood. Preferably, the inner base layers  26  and  27 , the U-shaped portions  18 , and the intermediate walls  14 , forming the base plank, are extruded of a less expensive reground scrap material or PVC, and the cap layers  32  and  34  are extruded of a virgin plastics material or PVC. The side walls  12  and the end walls  16  have a total predetermined thickness, for example, between 0.080 and 0.090″, and the cap layers  32  and  34  have a thickness of about 0.025″.  
         [0012]    Referring to FIG. 3, a series of deck planks  10  of a predetermined length, for example 12 feet, are installed on a supporting structure, for example, in the form of parallel spaced wood joists  45 . A C-channel strip  47  is first mounted on the joists  45  with suitable fasteners (not shown). The C-channel  47  is preferably formed of extruded plastics material or PVC and may have a height as shown in FIG. 3 to project into a slot  21  of the first deck plank  12 . The C-channel may also have a height which covers the entire edge wall  16  of the plank  12  and overlaps the top surface of the top wall  12 , thereby covering the slot  21  within the plank. After the first plank  12  is inserted into the C-channel, a retaining piece or strip  50  is inserted into the groove  21  on the opposite edge of the plank. A fastener, for example, in the form of a self-threading screw  52 , is inserted on a diagonal through the strip  50  and the corner of the plank and into the each wood joist  45 .  
         [0013]    As shown in FIG. 4, the retaining strip  50  is preferably extruded from a plastics material such as polypropylene and includes a V-shaped center portion  54 , opposite side wing or flange portions  56  and a vertical depending spacer portion  58 . Flexible sealing fins  62  are extruded on the outer edges of the flange portions  56 , and small V-shaped grooves  64  are extruded in the portion  54  to facilitate starting the self- tapping screws  52 . The retaining strips may be in short sections, for example, having a length of 1¾″ and are similar to the retaining biscuits disclosed in U.S. Pat. No. 6,402,415. The strips  50  may also be continuous along the entire length of the plank  12 . When the strips  50  are continuous and are inserted as shown in FIG. 3, the flexible sealing fin  62  forms a water-tight seal between the strip and the plank. Similarly, when the next adjacent plank  10  is installed, as shown in FIG. 3, the strip forms a water-tight seal with the adjacent plank, and the spacer portion  58  of the strip forms the proper spacing between the adjacent planks. With the water-tight seal between adjacent planks, rain water on the planks flows to the ends of the planks and not through the planks.  
         [0014]    When an edge wall  16  is exposed along an edge portion of the deck, for example, at a series of steps, an extruded cover strip  70  (FIG. 3) having a T-shaped cross-sectional configuration, is inserted into the corresponding groove  21  with sufficient interference fit to retain the strip. Prior to inserting the strip, a fastener or self-threading screw  52  is inserted diagonally through the lower portion of the outer plank  10 . Small V-shaped grooves  72  are extruded at the entrance of the U-shaped portions  18  of each plank  10  to facilitate starting a diagonal screw  52  when a retaining strip  50  is not required.  
         [0015]    From the drawings and the above description, it is apparent that a deck plank constructed in accordance with the present invention and its installation provides desirable features and advantages. For example, the deck plank  10 , with its side walls  12  and edge walls  16  co-extruded with capstock layers of different colors, provides the consumer or customer with a selection of one of the two colors for use as the top surface of the deck plank and also reduces the inventory required by a dealer who stocks the deck planks, thereby saving inventory expense. In addition, the grooves  21  in opposite edge walls  16  provide for receiving the hidden fasteners or tie strips  50  which provide for quickly installing the deck planks  10 . Furthermore, when continuous tie strips  50  are used between adjacent deck planks, the flexible sealing fins  62  provide for continuous water-tight seal between the adjacent deck planks along the length of the planks so that water does not drain through the planks between the opposing edge walls  16  of adjacent planks and onto objects below. The V-shaped portions  54  of each strip  50  and the guide grooves  64  and  72  provide for convenient and precision installation of the strip  50  with the self threading screws  52 .  
         [0016]    While the deck plank herein described and its method or construction and assembly constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to the precise plank and method described, and that changes may be made therein without departing from the scope and spirit of the invention as defined in the appended claims.