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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a portable, folding, vehicle-mountable observation tower that can be attached to a moving vehicle and safely permit a user to be positioned on the tower. More particularly, this invention relates to such a tower which can be releasably mounted to the cargo portion of any standard pickup truck without requiring any modification to the truck and which allows substantially full cargo capacity, whether the tower is in an up position or a folded and stored away position.  
           [0003]    2. Description of Related Art  
           [0004]    The prior art discloses a variety of collapsible towers typically used by hunters as towers which are secured to a moving vehicle, such as an ATV. Examples of various collapsible tower arrangements are illustrated in U.S. Pat. Nos. 4,800,986 and 5,409,081. The prior art also discloses various collapsible towers which are basically towed units. Illustrations of this kind of collapsible tower are shown and described in U.S. Pat. Nos. 4,442,919, 5,862,827, and 6,347,684 B1.  
           [0005]    U.S. Pat. No. 5,881,839 illustrates one example of a collapsible hunter&#39;s stand that is mounted in a truck bed or within the cargo area of a pickup truck. One obvious disadvantage of the mobile hunter&#39;s stand illustrated in this patent is clearly illustrated on the front page of the patent, where it is obvious that the stand or collapsible tower, when in an extended (usable) position, takes up some of the available space within the cargo area of the truck. This is one of the specific disadvantages that the features of the present invention seek to overcome.  
         SUMMARY OF INVENTION  
         [0006]    In accordance with the preferred features of the present invention, there is provided a portable, foldable observation tower for attachment to a movable vehicle that is adapted to be secured non-permanently via a support member to different sized cargo portions of a moving vehicle, and is further adapted to permit full usable cargo space capacity when the tower is being used, comprising: (i) a tower structure including means to allow a user to sit on the tower; and (ii) a support member to which the tower structure is secured, the support member including front and rear channel members to which the tower is releasably secured, each channel member having two end portions, each end portion of the channel members being in contiguous relation to a device that is slidable with regard to the channel members and adapted to be secured to the channel members, each device extending from a member that is structured to be force-fit and secured against the cargo frame of the vehicle in a non-permanent manner so as to lock the support member to the cargo frame.  
           [0007]    The collapsible observation tower in accordance with the features of the present invention, in addition to overcoming some very basic disadvantages of similar tower structures that are illustrated in the prior art, provides a collapsible, portable, and adaptable observation tower that can be supported by a moving vehicle, and which in addition offers the following combination of advantages:  
           [0008]    (i) The tower structure itself in accordance with the features of the present invention does not require being bolted or permanently secured to the vehicle or the truck bed. Therefore, no holes have to be drilled into the vehicle or truck bed. The tower is either clamped or strapped into position;  
           [0009]    (ii) Due to the way the tower is mounted to the side rails of the vehicle, full cargo space capacity is allowed with the tower in place on the truck bed (in the cargo area);  
           [0010]    (iii) The tower structure along with its support member in accordance with the features of the present invention permits the same tower structure to be mounted on all sized pickup trucks, e.g., compact, full-size, short-bed, long-bed, stepside, and flairside;  
           [0011]    (iv) The tower structure and its support member can be mounted on truck cargo areas along with tool boxes that are side-mounted or cross-mounted;  
           [0012]    (v) The tower structure and its support member can be adjusted front to back on either the side rails of the vehicle or on its permanently mounted tool boxes;  
           [0013]    (vi) The tower structure and its support member is reachable from the tailgate portion or the rear bumper portion of the truck. Therefore, the cargo area of the truck can be fully utilized, and a user does not have to crawl under or over any portion of the tower structure and its support member to use the cargo space;  
           [0014]    (vii) Both the tower structure and its support member can be installed and removed for storage off the truck by one person;  
           [0015]    (viii) Both the seat portion and the folding foot platform of the tower structure are incorporated into the tower structure;  
           [0016]    (ix) The seat portion of the tower structure includes a safety/steady rest rail that swings up for clearance and which provides a safety feature for the user;  
           [0017]    (x) The tower structure includes a removable cooler/gear rack and a removable table top for use as a tray; and  
           [0018]    (xi) The tower structure is not only mobile, it is truly a portable structure.  
           [0019]    In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0020]    For a fuller understanding of the invention, reference is made to the following detailed description of various preferred embodiments of this invention taken in connection with the accompanying drawings in which:  
         [0021]    [0021]FIG. 1 is a perspective view of a cargo portion (i.e., the rear view) of a truck including the lower portion of a tower structure positioned on a support member secured on the side walls of the cargo area in accordance with the features of the present invention;  
         [0022]    [0022]FIG. 2 is a perspective view of a tower structure and support member in a folded position ready for storage in accordance with the features of the present invention;  
         [0023]    [0023]FIG. 3 is a perspective view of a tower structure and support member in an extended position, ready for being secured to a vehicle and for use in accordance with the features of the present invention;  
         [0024]    [0024]FIG. 4 is a perspective view of various parts of the tower structure and its support member before being assembled; and  
         [0025]    [0025]FIG. 5 is an end elevational view, partially in cross section, of an end portion of a support member which is secured to a side wall of a truck cargo area by a clamp in accordance with the features of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0026]    In the following detailed description, the tower structure system (i.e., the tower and the tower support member) in accordance with the features of the present invention is described in conjunction with its various applications. In this context, however, it should be noted that those of ordinary skill in the art will contemplate alternative applications of the subject matter according to the present invention. Furthermore, the present invention is not meant to be limited to only the applications described and illustrated herein.  
         [0027]    [0027]FIG. 1 clearly illustrates one of the most basic advantages of the present invention. As shown in FIG. 1, there is illustrated a truck generally referenced as  10 , having a cargo area generally referenced as  11 . A tower structure system in accordance with the features of the present invention is in position within cargo area  11  and is releasably secured to the cargo area  11  in a manner such that full cargo space capacity is permitted. Due to the manner by which the tower generally referenced by  12  is mounted on the truck side rails  15  and  16 , the major advantages of the present invention over prior art systems are achieved. As illustrated, the tower portion  12  of the tower structure system is non-permanently secured to truck  10 . Tower  12  is secured to a tower support member generally referenced by  12 A which is secured to truck  10 . The tower support member  12 A consists of front and rear channel members  19  and  20 , respectively, in combination with angle beam members  21  and  22 . Each end portion  17  of each of the channel members  19  and  20  is in contiguous relation to a device  18  that is slidable with regard to the channel members and adapted to be secured to each channel member  19  and  20  at their end portions  17 . Each device  18 , preferably in the form of a plate member, is firmly secured and extends from each of the angle beam members  21  and  22 , e.g., by welding the device to the angle beam members  21  or  22 . Each angle beam member  21  or  22  is structured so as to be force-fit against one of the truck cargo side rails  15  or  16 . In the embodiment illustrated in the drawings, each angle beam member  21  and  22  is formed of a right angle of about 90°, and is force-fit against an upstanding side rail  15  or  16  of the cargo area by securing the internal surface portion of each angle beam member against the inside and upper surfaces of each side rail member  15  or  16 , as illustrated in FIG. 1. Each device  18  is preferably in the form of an upstanding plate member which lies in contiguous relation against the channel members  19  and  20 , respectively. Each channel member  19  and  20  includes a plurality of openings (holes)  26 . Holes  26  also extend through each of the channel members  19  and  20 . When each angle beam member  21  and  22  is in its proper position, i.e., force-fit against the truck cargo side rail members  15  and  16 , then an opening (hole)  26  on each upstanding plate member  18  is matched with a matching opening  26  on each channel member  19  and  20 , and a threaded bolt fastener  28  is firmly positioned within a set of openings to firmly secure the tower support member to an individual truck cargo area to which the tower structure system in accordance with the features of the present invention is desired to be secured. Also, as illustrated in FIG. 1, each leg member  29  of tower  12  is secured to a channel member  19  and  20  by clip devices  30 . The clip devices  30  can be any of various types of clip devices that can secure each of the tower legs  29  to channel members  19  and  20 , but are devices that preferably form a U-shaped channel so that each clip device can locate and position a leg member  29  of tower  12  in place. Each clip  30  is retained in position by, for example, clevis pins which secure each of the vertical legs  29  of tower  12  to clip devices  30 .  
         [0028]    [0028]FIG. 2 illustrates tower  12  in a folded position (i.e., a position used for storing tower  12  including tower support member  12 A when not in use). As shown, tower  12  includes a foldable seat member generally referenced by  31  and a safety bar  33  which can rotate so as to be able to fit about the upper body portion of a user, and thereby help to prevent a user from falling out of the tower when seated therein. Tower  12  includes a plurality of cross bars  32  which serve as the ladder feature of the tower, i.e., enabling a user to climb up or down the tower, when the tower is in an extended and usable position as shown in FIG. 3.  
         [0029]    Tower  12  is illustrated in an extended and ready-to-use position secured to tower support member  12 A in FIG. 3. All that is required is that tower support member  12 A be secured to the cargo area of a truck. As shown, tower  12  includes an A-frame ladder portion  34 ; a folding seat member  31  which includes a rear back support member  35  and a seat support member  37 ; a safety support rail  33  which helps prevent the user from falling out of the seat member  31  and which rotates so as to enable the user to climb down from the tower; a footrest member  39 ; and a tray-type storage member  40 .  
         [0030]    Various other options can be included with tower  12 , depending upon the particular use of the tower, i.e., for hunting, for wild game and bird watching, for photography, for general surveillance purposes, etc. For example, items such as a cooler tray, tool tray, cup holder, gun rack, bow and arrow rack, camera holding device, etc. are just a few examples of the various options that can be included. The portable folding observation tower  12  as shown in FIG. 3 is able to be secured to a support member  12 A in accordance with the features of the present invention, which then enables tower  12  to be mounted on any standard pickup truck  10  (see FIG. 1) without any modification to the truck. When tower  12  is in its folded position (see FIG. 2), one can transport the tower and its support member in the truck cargo and still be left with full cargo capacity. When in an up or extended or “in use” position (see FIG. 3), and positioned in the truck cargo (see FIG. 1), tower  12  extends about ten to twelve feet of height into the air above the truck and still leaves the truck with full cargo capacity. However, it is within the scope of the present invention that the tower  12  can extend to various other heights. Once the tower assembly is assembled and the tower is to be secured or mounted on the truck in a ready-to-use position, no bolting or unbolting is required. The user simply clamps or unclamps the tower structure from or to the truck, as needed.  
         [0031]    The portable observation tower as defined herein is easily mounted and removed from a pickup truck to which it is easily secured, and is also completely collapsible and removable. The observation tower with its support member in accordance with the unique features of the present invention is designed to fit within and used with any standard pickup truck, short or long bed, step or flare side. The tower system can be shipped in a completely disassembled condition, and assembled at the location where it will be used. When assembled, the tower system (tower  12  and tower support member  12 A) can be installed on the side rails  15  and  16  of a pickup truck (see FIG. 1). When in transport, the tower system can be locked in a collapsed position, thereby removed from any obstacles that may be encountered by the tower if it was in a totally upright (ready for use) position. When in use, the tower is locked in the upright position for a comfortable, stable, elevated seating platform with a footrest, backrest, and a steady rest for birdwatching, hunting, surveillance, or any other observation type requirements it may serve.  
         [0032]    One preferred method for assembling the observation tower along with its support members is described herein below with reference to FIG. 4. The process of assembling the tower can begin by positioning (i.e., mounting) each of the two angle beam members  21  and  22  onto the side rails  15  and  16  of truck  10 , which can best be seen in FIG. 1. Thereafter, front and rear channel members  19  and  20  are positioned on angle beam members  21  and  22  and secured in place by aligning an opening  26  (see FIG. 1) on the channel members with an opening  26  on plate member  18  and inserting a threaded bolt fastener through both openings to secure the support member  12 A for the tower in place. Thereafter, the seat and backrest section  31  is secured to that part of the tower structure  41  that forms the rear part of the ladder  34  (see FIG. 3) for the tower to form a stepladder and folding platform. That portion of the tower structure which includes the ladder steps  32  and a footrest member  39  is then secured to the folding seat member  31 , forming a basic tower structure. The four leg members  29  of the tower structure are then secured to the channel members  19  and  20  by clip devices  30  (see FIG. 1). Thereafter, the safety rail  33  is then mounted to the folding seat member  31 . An optional removable storage platform or a removable tabletop could then be secured to the tower.  
         [0033]    The tower system in accordance with the features of the present invention allows for the use of the pickup truck cargo space to carry a full cargo load while the tower system lies in place within the truck, i.e., in either an upright or collapsed position. The tower system, including both the tower structure  12  itself and the support structure  12 A which enables the tower to be releasably secured to the truck, can be removed from the pickup truck in a fully assembled condition for storage, or disassembled to save storage space.  
         [0034]    [0034]FIG. 5 illustrates one particular example of a mechanism illustrating how the support member  12 A can be releasably secured to the body of a truck. Illustrated in cross section is an angle channel member  22 , preferably a right angle member, which is shown secured to the body side section  16  of a truck by a clamp screw arrangement  40 . To prevent the channel member  22  from damaging the truck body when it is forced into contact with the truck cargo side wall  16 , a rubber mat  41  is preferably positioned between the angle channel member  22  and the truck body  16  during the time that the angle channel member  22  is clamped by the clamp screw  40  to the truck body  16 .  
         [0035]    The present invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.

Summary:
A tower system adapted to be secured non-permanently to different sized cargo portions of a moving vehicle is disclosed. The system comprises (i) a tower structure including means to allow a user to sit on the tower; and (ii) a support member to which the tower structure is secured, the support member including front and rear channel members to which the tower is releasably secured, each channel member having two end portions, each end portion of the channel members being in contiguous relation to a device that is slidable with regard to the channel members and adapted to be secured to the channel members, each device extending from a member that is structured to be force-fit and secured against the cargo frame of the vehicle in a non-permanent manner so as to lock the support member to the cargo frame.