Abstract:
A lightweight plastic pick up truck box for use on street grade, light-duty pick-up trucks. It is another aspect of the present invention to provide a plastic pick up truck box with a light-duty truck dumping mechanism for pick-up trucks utilizing plastic molded truck box beds, with the tilting mechanism being used to dump the contents out of the pick-up truck box bed. Another embodiment of the invention includes a double-folding tailgate/ramp which can be utilized to extend to the ground in order to allow for easy carrying and loading of a pick-up box. The combination of the plastic molded pick-up truck box bed having inserts therein with a hydraulic stanchion support and dumping mechanism yields a light-duty truck which can be used for dumping. Although in its most simple form, a singular stanchion and hydraulic dumping mechanism may be utilized, more than one stanchion and hydraulic lifting mechanism may also be utilized.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]     This patent application claims the benefit of U.S. Provisional Application No. 60/414,970 filed on Sep. 30, 2002, and co-pending U.S. patent application Ser. No. 10/530,257, which will mature into U.S. Pat. No. 7,032,977. 
     
    
     TECHNICAL FIELD  
       [0002]     This patent application relates to pick up trucks with a truck box attached to the rear of the truck, and more particularly relates to a formed plastic pick up truck box, adaptable for attachment to a dump truck tipping mechanism for use with a light-duty truck.  
       BACKGROUND OF THE INVENTION  
       [0003]     Pick up trucks have become a mainstay in the automotive market for agricultural, commercial, landscaping and other uses. Generally, these pick up trucks are used for loading and hauling, but sometimes it is easier to dump the load out of a pick up truck than it would be to unload the cargo box of the pick up. However, dump trucks are usually large heavy-duty trucks with heavy-duty hydraulics systems for lifting the relatively heavy metal truck box beds. The lifting and tipping systems not only have to lift the truck box itself but it must also lift the contents of the box as well.  
         [0004]     In order to increase fleet mileage and better comply with environmental standards, the automotive industry has been trying to reduce the weight of their vehicles. They have been increasingly looking at resin plastic pick-up boxes, as they are sometimes lighter in weight than a traditional steel metal pick-up truck boxes. One type of pick-up truck box made of plastic is made by a powder molding technology owned by 3DM Technologies, Inc., of Troy, Mich. The pick-up truck box made by their process is approximately 100 pounds less than a standard metal pick-up truck box, lending itself to a much simpler method and mechanism for affecting a dump truck tipping mechanism. By powder molding the truck box itself, stanchion supports and other metallic inserts can be molded directly into the pick-up truck box, acting as connecting and attachment points for the hydraulic dumping mechanism.  
         [0005]     It is an aspect of the present invention to utilize the reduced weight and singular component truck box bed created by the use of plastic forming technology for making a light weight, one piece plastic body, and especially a plastic truck box bed that can be easily lifted, The PCT International Patent Application Serial No. PCT/US02/03298 for the invention entitled “Processes For Forming Plastic, Apparatuses For Forming Plastic, And Articles Made Therefrom”, also owned by the present owners of this application, is incorporated herein by reference. U.S. Provisional Patent Application No. 60/414,969 is also incorporated herein by reference.  
         [0006]     Therefore, it is an aspect of the present invention to provide a lightweight plastic pick up truck box for use on street grade, light-duty pick-up trucks. It is another aspect of the present invention to provide a plastic pick up truck box with a light duty dumping mechanism. This is especially desirable for providing a lightweight dumping pick up truck without having the need to purchase a special heavy-duty truck. Also, as the truck box is made by various plastic forming technologies, such as the powder molding technology described above, the weight of the box should be less than the conventional truck boxes, and a light duty dumping mechanism can be utilized.  
         [0007]     Because the payload capacity may be increased due to less weight, this makes the dump truck tipping mechanism more desirable. The present invention provides these aspects and advantages and also provides a tailgate construction which can reach down to the ground such that a normal size light-duty pick-up truck can be utilized for running various tools and equipment directly up the tailgate into the bed of the truck, allowing the easy loading of wheeled vehicles, such as heavy duty wheelchairs, recreational vehicles such as ATVs and motorcycles, as well as the loading of small livestock, including dogs and the like.  
       SUMMARY OF THE INVENTION  
       [0008]     In accordance with the above-noted advantages and desires of the industry, the present invention provides a lightweight plastic pick up truck box for use on street grade, light-duty pick-up trucks. It is another aspect of the present invention to provide a plastic pick up truck box with a light duty dumping mechanism for use in a street grade pick-up truck, a method of making the same, and a standardized pick-up truck conversion kit for converting an off-the-belt plastic pick-up truck box to a dumping mechanism. The present invention includes a various types of plastic pick up truck boxes and beds, along with plastic truck beds having molded-in stanchion supports and other metallic inserts molded directly into the plastic pick-up truck box itself, in order to act as connecting and attachment points for the hydraulic dumping mechanism which is called for in one embodiment of the present invention.  
         [0009]     One specific preferred embodiment has certain features including a plastic pick-up box for attachment to the chassis of a pick-up truck including a hydraulic lifting mechanism and a compatible tailgate for dumping the contents of the pick-up box.  
         [0010]     In yet another embodiment of the present invention, a method of making such a plastic pick up truck box, along with its complementary plastic cousin, that being a plastic dumping pick-up truck mechanism is also disclosed, wherein the pick-up box is molded utilizing various plastic forming technologies, and, in the case of the dump truck, also incorporating certain metallic inserts into the mold prior to the melting of the plastic, resulting in a one piece construction of a pick-up box that can be attached to the chassis of a standard pick-up truck.  
         [0011]     The invention is particularly useful for applications of small load movement, and especially in situations where a small pick-up truck is easier to maneuver, for example apple orchards and the like, between the trees, etc. Other advantages include the lower purchase price of a pick-up truck compared to a full size dumping truck, as well as the fact that a normal pick-up truck does not need to be stopped and weighed at every weigh station on an expressway.  
         [0012]     Although the invention will be described by way of examples hereinbelow for specific embodiments having certain features, it must also be realized that minor modifications that do not require undo experimentation on the part of the practitioner are covered within the scope and breadth of this invention. Additional advantages and other novel features of the present invention will be set forth in the description that follows and in particular will be apparent to those skilled in the art upon examination or may be learned within the practice of the invention. Therefore, the invention is capable of many other different embodiments and its details are capable of modifications of various aspects which will be obvious to those of ordinary skill in the art all without departing from the spirit of the present invention. Accordingly, the rest of the description will be regarded as illustrative rather than restrictive. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     For a further understanding of the nature and advantages of the expected scope and various embodiments of the present invention, reference shall be made to the following detailed description, and when taken in conjunction with the accompanying drawings, in which like parts are given the same reference numerals, and wherein:  
         [0014]      FIG. 1  is a side elevational view of a light-duty pick-up truck mechanism made in accordance with the present invention;  
         [0015]      FIG. 2  details the hydraulic lifting mechanism in place within the light-duty plastic pick-up truck box;  
         [0016]      FIG. 3  is a detail of a stanchion for lifting;  
         [0017]      FIG. 4  is an exploded perspective of inserts being placed into the mold;  
         [0018]      FIG. 5  is an exploded perspective showing male and female reinforcing metal mesh components being placed into the mold;  
         [0019]      FIG. 6  illustrates the male and female molds held against each other; and  
         [0020]      FIG. 7  is a cutaway perspective view of a truck box bed made in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     With combined reference to  FIGS. 1-4 , there is shown a first embodiment of the present invention with a plastic pick up truck box in combination with a second embodiment of the present invention that includes a tipping mechanism generally denoted by the numeral  10 . Mechanism  10  may include a hydraulic lifting mechanism  12  attached to a plastic material truck box bed  14 .  FIG. 2  shows more details of a stanchion  18  which is attached to the hydraulic lifter  12  of  FIG. 1 . Stanchion  18  is shown in its relative placement to the plastic pick-up truck box  14  and is the acting member to effect the tipping of the box. Stanchion  18  may be attached to a metal stanchion transverse support  20  located on the underside of the truck box, as shown in  FIG. 2 . The hydraulic lifter  12  would then be capable of being activated from within the cab of the truck  22  as seen in  FIG. 3 .  
         [0022]     As shown in  FIG. 1 , the hydraulic cylinder  12  is a single stroke hydraulic cylinder and is attached to stanchion  18  which extends upwardly and is attached to the underside of the truck box body. It must be noted that the present invention also contemplates any number of hydraulic cylinders, as well as any other conventional tipping mechanism. What is important, though, is that the metal stanchion transverse supports should be able to be molded into the plastic in order to hold it in place. In this embodiment, hydraulic cylinder  12  extends, stanchion  18  rises up and tips the truck box bed which is pivotally attached to the truck frame by pivot  17 .  
         [0023]     The truck box body which makes this configuration possible is made by various plastic forming technologies, which also allows for the molded-in inserts of the transverse metal stanchion support  20  as seen in  FIG. 3 . The terms “resin”, “thermoset plastic”, “liquid plastic”, “powder” and “particulate” are used herein interchangeably. Of course, any number of stanchion supports may be utilized, and they may be incorporated into the plastic molded truck box bed, as well as they may attach to any number of reinforcements within the plastic molded material itself. The stanchion pivots on a pivoting access  21  which allows the truck box body  14  to tip up when the hydraulic cylinder  12  is extended. The hydraulic lines appear in the hydraulic cylinder  12  in  FIG. 1 , and are activated by a hydraulic line activator and/or switch located within cab  22 . Such means for activation is not shown, although the actuator is standard in the art. The top side of truck box body  14  is illustrated in  FIG. 3 , as well as shown in  FIG. 4 . Truck tailgate  16  may also be made out of the powder mold technology. It is envisioned that tailgate  16  could be made into a configuration that will touch the ground when the truck box is tipped, thereby allowing wheelchairs, motorcycles, dogs, livestock, etc., to climb into the truck box.  
         [0024]     Therefore, the present invention has provided a new plastic formed pick up truck box bed, as well as another embodiment that may also include a tipping mechanism in combination with a plastic molded truck box body for making a regular sized one-ton pick-up truck into a tilting dump truck. The plastic mold truck box body makes possible the tilting or tipping mechanism because the truck box body made of powder mold is approximately 95 pounds less than a standard steel pick-up box. Because there is less weight to lift, the tilting mechanism becomes very simple. When a payload of one ton is placed in the truck, the reduced weight of the truck box body significantly increases the capability of a hydraulic cylinder to lift, which enables the present invention.  
         [0025]     Furthermore, the present invention is especially enabled because the plastic mold technology allows for any reinforcing insert to be placed directly into the plastic mold itself. For example, the metal support bars which act as transverse stanchion supports, such that the foamed plastic center can foam up around and encapsulate the stanchion supports, thereby giving a high rigidity factor to the truck box body itself. It is this combination of factors, i.e. the light-weight construction, the ability to encapsulate and incorporate metal stanchion support inserts into the mold, as well as the use of a hydraulic cylinder which is the preferred combination for the present invention.  
         [0026]      FIG. 4  illustrates a female plastic mold halve generally denoted by numeral  30  wherein inserts  32  are placed on the floor of the mold  34  in and around the mold wheel well indentation. As disclosed in the reference incorporated herein, the plastic mold procedure generally includes two complementary molds, a male mold and a female mold. The plastic mold method includes clamping both male and female molds together and forming plastic therebetween.  
         [0027]     Looking next to  FIG. 5 , there is shown a female plastic mold halve  30  with inserts  32  located therein. A male metal reinforcing mesh component  40  having a male mesh wheel well indentation  44  may be placed into the mold prior to the placement of the foaming plastic. Also shown in  FIG. 5  is a male mold halve  48  which is also receiving a female metal reinforcing mesh component having a female mesh wheel well indentation  46 . Both the male and female plastic mold halves  30  and  48 , respectively, are attached to a tipping mechanism  36  in order to dispose of the unmelted contacted plastic particulates once the desired skin thickness has been achieved.  
         [0028]     In essence, in this one embodiment, the two plastic mold halves may be contacted with plastic for a length of time to achieve a certain skin thickness, preferably from about 1 millimeter to about 10 millimeters. The general experience is that a mold heated to at least 300° Fahrenheit contacting a polypropylene or polyurethane plastic particulate material needs approximately one minute per 1 millimeter of desired thickness for contacting. In the event that a coarser material, such as pellets rather than powder is contacted, those contacting times may need to be longer. In the use of liquid plastic, setting times are dictated by the various Once the desired thickness has been achieved, the excess powder contacting the heated mold is removed, for example by tipping, or by vacuum, and then any desired inserts are placed into the female mold, followed by the placement of foamable thermoplastic particulate material. The male mold is then placed over the female mold, as shown further hereinbelow with reference to  FIG. 6 , and the heat from the heated molds “kickoff” and expand the thermo plastic material to the height that the male and female molds are held apart. Once the part has been achieved, the mold is cooled, and the resulting part has been manufactured.  
         [0029]     Looking now to  FIG. 6 , there is shown the male and female mold halves of  FIG. 5  in their nested configuration held in place by a trunion generally denoted by the numeral  52 , including a trunion pillar  54 . The male and female molds  48  and  30 , respectively, are nested together and held together at a particular distance apart to achieve the desired thickness of resulting article, and placed upon trunion platform  56 . After the molds have been cooled, the resulting article appears as that shown in  FIG. 7 , and is generally denoted by numeral  60 . The powder mold truck box bed  60  includes an upper skin  62 , a lower skin  64 , and a foamed plastic interior  66 . As one can see, inserts  32  (from  FIG. 4 ) are locked into place and secured via the foamed plastic interior  66 . The inserts have been placed into the mold in their desired locations so that they may be merely bolted on to the stanchion supports as illustrated in FIGS.  1  thru  3 .  
         [0030]     Suitable materials especially include polyethylene and polypropylene among other plastics, and these materials may be formed by injection molding, vacuum molding, transfer molding, or any other suitable plastic forming technologies.  
         [0031]     Further stanchion supports and inserts may be necessary for different configurations of varying pick-up truck box beds, and those modifications can be made without undo experimentation on the part of the practitioner.  
         [0032]     A plastic pick up truck box can be made with the present invention with a light-duty dumping mechanism for use on a pick-up truck chassis. This truck box may comprise a plastic pick-up truck box bed having a sandwiched plastic configuration formed from plastic material in a two sided mold, and where said plastic pick-up truck box bed may include an inner and an outer skin with a center extending therebetween. At least one metallic stanchion supporting insert may be encapsulated within the plastic configuration pick-up truck box bed. Furthermore, a lifting mechanism can be attached to at least one metallic stanchion encapsulated within the pick-up truck box bed, and the lifting mechanism would also extend and be attached to the chassis of the pick-up truck. A pivot point is located between and connecting the pick-up truck chassis and the double skinned plastic configuration pick-up truck box bed, whereby the lifting mechanism then lifts against the stanchion supporting insert and tilts the pick-up truck box bed against the pivot point so that the pick-up truck bed is able to dump its contents.  
         [0033]     In order to make the plastic pick up truck box stronger, reinforcing metallic mesh sheets may be formed to a likeness of the pick-up truck box bed, and then be formed right into the center of the sandwiched configuration to provide a higher modulus of strength to the pick-up truck box bed. With this construction, a tailgate capable of extending to the ground for easier loading can be realized.  
         [0034]     The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings with regards to the specific embodiments. The embodiment was chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims which are appended hereto.