Abstract:
A roll-out cargo bed comprises a frame structure configured to connect to a cargo bed of a vehicle, a plurality of bearings mounted to the frame structure, a deck connected to the frame structure, and a cable tension release mechanism disposed within the frame structure. The cable tension release mechanism may comprise a plurality of pulleys strategically spaced to facilitate extending the roll-out cargo bed. The roll-out cargo bed may further comprise a damper mechanism to reduce vibrations during transportation.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This application claims priority to U.S. Provisional Patent Application No. 60/539,161 entitled “ROLL-OUT TRUCK BED” and filed on Jan. 26, 2004 for Tony Kobylski and Terry A. Kobylski, which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to extendable cargo beds and more particularly relates to roll-out cargo beds with a cable tension release mechanism. 
   2. Description of the Related Art 
   Trucks and vehicles with a cargo area are generally used to transport equipment from one location to another. Typically, a cargo bed is built into the body of a vehicle to provide storage space for transporting various items. Problems arise, however, when a user must load and unload the equipment from the cargo area. The sides of the vehicle, which define the cargo area and enclose the equipment during transportation, become a barrier to the user while loading and unloading the equipment. Often, the user is not able to reach or pull out the items in the cargo bed, especially those items located near the cab of a vehicle. Consequently, the user must climb into the cargo bed, lift or move a particular item, and then jump out of the vehicle to finish unloading the item, which can be an extremely difficult and time-consuming process. Usually more than one person must collaborate to effectively load and unload a vehicle. The loading and unloading process can be costly and inconvenient and, in certain instance, can increase the health risk of the loader due to poor ergonomic conditions. 
   In recent years, extendible cargo beds that retract into the vehicle for transportation have enabled users to load/unload items outside of the vehicle cargo area. The extendible cargo beds available, however, are generally fraught with many faults. First of all, the moving platform for loading cargo is often difficult to control or manipulate. The weight from the cargo on the extended platform can cause the platform to slant and can stretch connecting cables, often destroying fragile cable tension release mechanisms. In certain cases the platform may derail, causing other calamities. In addition, the extendible cargo beds are often difficult to install and remove; thus, if the cable tension or the rail systems of an extendible cargo bed fail, the user may have a difficult time fixing the associated problems. 
   Another common problem that occurs in extendible cargo beds is vibration. During transportation, the motion from traveling and the load on the extendible cargo bed can cause the platform and corresponding frame members to sway and knock against each other. The resulting noise can be annoying to anyone in close proximity. In addition, the motion may negatively affect the components of the extendible cargo bed. 
   From the foregoing discussion, it should be apparent that a need exists for a reliable extendible cargo bed with an improved cable tension release system. Beneficially, such an apparatus and system would minimize the number of stresses that disrupt a cable tension release system. Additionally, the extendible cargo bed would be easy to control and would be easily installed/removed from the bed of a vehicle. 
   SUMMARY OF THE INVENTION 
   The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available extendible cargo beds. Accordingly, the present invention has been developed to provide a roll-out cargo bed with a tension release mechanism that overcomes many or all of the above-discussed shortcomings in the art. 
   A roll-out cargo bed, in one embodiment, comprises a frame structure configured to connect to a cargo bed of a vehicle, a plurality of bearings mounted to the frame structure, a deck connected to the frame structure, and a cable tension release mechanism disposed within the frame structure. The cable tension release mechanism facilitates safely extending the deck of the roll-out cargo bed. In one embodiment, the cable tension release mechanism comprises a plurality of pulleys strategically positioned to minimize the amount of force required to release locking pins, thereby enabling the user to easily extend the roll-out cargo bed. 
   In one embodiment, the cable tension release mechanism further comprises a plurality of brackets for mounting the pulleys to the frame structure, a plurality of cables, a plurality of spring loaded locking mechanisms, a polygonal-shaped rod, a pull lock knob configured to connect to the polygonal-shaped rod, and a pull rod sleeve to connect the polygonal-shaped rod to the cables. Handles, such as U-shaped handles, may be used to control the roll-out cargo bed and to function as a stop to prevent overextending associated cables. The polygonal-shaped rod, in one embodiment, may be inserted into a corresponding polygonal shaped hole in a cross member of the frame structure, consequently limiting the rotational movement of the polygonal-shaped rod. Thus, the polygonal-shaped rod prevents the cables from twisting and stretching. 
   In another embodiment, the roll-out cargo bed may further comprise a damper mechanism to reduce vibrations in the frame structure during transportation and other activity. The damper mechanism may comprise a bumper stop connected to the frame structure in one embodiment. Consequently, the deck or other components of the frame structure may be frictionally retained in a locked position against the bumper stop. The damper mechanism further protects the frame structure and reduces motion transferred to the cargo items. 
   Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
   Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
   The present invention provides a tension release mechanism that increases the stability and utility of the roll-out cargo bed. In addition, a damper mechanism reduces problems associated with vibration. These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
       FIG. 1A  is perspective view illustrating one embodiment of a roll-out cargo bed in a storage position in accordance with the present invention; 
       FIG. 1B  is a perspective view illustrating one embodiment of a roll-out cargo bed in an extended position in accordance with the present invention; 
       FIG. 2  is an exploded view of one embodiment of a roll-out cargo bed of the present invention; 
       FIG. 3A  is an end view illustrating one embodiment of a plurality of bottom rails attached to a mounting strap; 
       FIG. 3B  is a side view illustrating one embodiment of a bottom rail in accordance with the present invention; 
       FIG. 3C  is a cross-sectional view of one embodiment of a bottom rail in accordance with the present invention; 
       FIG. 3D  is a partial side view of a top rail in accordance with the present invention; 
       FIG. 4  is a top view illustrating one embodiment of a frame structure of the present invention; 
       FIG. 5  is a perspective view of one embodiment of a roll-out cargo bed of the present invention without a deck; 
       FIGS. 6A-6C  are side views of various embodiments of a plurality of cross members in accordance with the present invention; 
       FIG. 7  is a top view of one embodiment of a pulley assembly of a cable tension release mechanism in accordance with the present invention; 
       FIGS. 8A-8B  are an end view and side view of one embodiment of a bumper stop of a damper mechanism in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
   Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     FIG. 1A  illustrates one embodiment of a roll-out cargo bed  1000  connected to a truck bed  1002 . The roll-out cargo bed  1000  preferably fits within the truck bed  1002  such that a tailgate  1004  or other type of enclosure may be opened and closed without obstruction. The roll-out cargo bed  1000  comprises a deck  100 , a plurality of handles  120 , a frame assembly, and a pulley assembly (not shown). 
   The deck  100  rests on top of the frame assembly in certain embodiments. The combined structure can typically support about the same amount of weight that a truck bed  1002  can support, which is about 1200 lbs. The deck  100  may be sized to correspond to the dimensions of a particular truck or vehicle. Thus, the deck  100  can efficiently store or transport nearly the same amount of equipment as the original truck bed  1002 , or the cargo bed of a chosen vehicle. Typical sizes may range between about 60 to about 94 inches. In certain embodiments, the roll-out cargo bed  1000  may be angled to fit the angled beds  1002  or angled tailgates  1004  of certain trucks currently available in the market. Consequently, the deck  100  does not catch on the tailgate  1004 . Additionally, the deck  100  may be carpeted or the like to provide a pleasant work surface. In one embodiment, the deck  100  is spray-coated with urethane to prevent weathering. The deck  100  may also provide protection to the original truck bed  1002 . 
   The roll-out cargo bed  1000  of  FIG. 1A  is in a storage position  1006 , which comprises the deck  100  being located within the confines of the truck bed  1002  and being locked by pins to the frame assembly. The storage position  1006  may also comprise a transport position for transporting cargo on the roll-out cargo bed  1000 . 
     FIG. 1B  illustrates one embodiment of a roll-out cargo bed  1000  in an extended position  1008 . In an extended position  1008 , a user may access equipment  110  from the sides of the deck  100 . 
   To facilitate extending the roll-out cargo bed  1000 , a plurality of handles  120  may be attached to the frame assembly and/or deck  100 . The handles  120  enable one user to control the movement of the roll-out cargo bed  1000  using one or two hands. Of course, more than one user may assist pulling the deck  100  from the storage position  1006  to an extended position  1008  if desired. A U-shaped handle  120  may also have a dual function as a stop to help maintain the tension of the cables, which will be described below in greater detail. In addition, a pull lock knob  140  allows a user to release spring-loaded locking pins. Consequently, a user can control how far the deck  100  extends with the pull lock knob  140 . 
   To accommodate the user, the roll-out cargo bed  1000  may have a plurality of locking positions to secure the deck  100  in a stable position. For example, the roll-out cargo bed  1000  may be locked in a storage position  1006  as discussed above, or the roll-out cargo bed  1000  may be locked in a variety of extended positions  1008 . In one embodiment, the roll-out cargo bed  1000  has a minimum of three locking positions. In  FIG. 1B , the roll-out cargo bed  1000  is locked midway between the tailgate  1004  and the cab  1012  of the truck. In a fully extended position, the deck  100  may lock with about 18 inches of the deck  100  remaining just inside of the tailgate  1004  in one embodiment. Consequently, a user may access nearly the entire deck  100  from outside of the vehicle. For discussion purposes, references to “front” refer to the general direction toward the cab  1012  of the truck and references to “back” refer to the direction toward the tailgate  1004  of the truck. 
     FIG. 2  further illustrates the functional components of one embodiment of a roll-out cargo bed  1000  of the present invention. The components include a deck  100 , a frame assembly  200 , and a pulley assembly  300 . The frame assembly  200  comprises straps  220 , bottom rails  240 , top rails  260 , and cross members  280 . The pulley assembly  300  comprises handles  120 , a pull lock knob  140 , an adjustment mechanism  310 , a square rod  320 , a bracket stop  330 , a cable sleeve  340 , a plurality of pulleys  350 , cables  360 , spring-loaded locking mechanisms  370 , and bumper stops  380 . 
   The deck  100 , as illustrated, may be secured to a frame assembly  200  with a plurality of fasteners such as bolts or screws  102 . In one embodiment, the deck  100  is made of plywood, though any rigid, durable material may be appropriate. Additionally, the deck  100  may consist of one flat piece, or the deck  100  may consist of several smaller sections. 
   In one embodiment, the deck  100  includes holes  104  to connect the deck  100  to the frame assembly  200 . In one embodiment, screws  102  are screwed into tapped holes  282  in the cross members  280  of the frame assembly  200 . The number of holes  104  may vary with the number of cross members  280 . For example, a 94-inch embodiment of a roll-out cargo bed  1000  may include four cross members  280 . Accordingly, the deck  100  may have eight holes  104 , two holes  104  corresponding to each cross member  280 . Alternatively, a 60-inch embodiment of a roll-out cargo bed  1000  may only include three cross members  280 . Thus, the deck  100  may comprise only six holes  104 , two holes  104  corresponding to each cross member  280 . 
   The frame assembly  200  may be secured to a truck bed  1002  by way of a plurality of straps  220 . The straps  220  may contain holes  222  to secure the roll-out cargo bed  1000  to the truck bed  1002  with fasteners such as bolts. In one embodiment, the straps  220  are made from steel to provide support to the roll-out cargo bed  1000 . The bottom rails  240  may be welded to the straps  220  in certain embodiments. The bottom rails  240  may be made from a hollow, rectangular tube. The top rails  260  may be L-shaped and may fit on top of the bottom rails  240 . The rails  240 ,  260  and cross members  280 , in certain embodiments, are made from steel. The cross members  280  accordingly may be welded to the top rails  260 . 
   The pulley assembly  300  of the present invention allows a user to control the roll-out cargo bed  1000  as the deck  100  transitions from a locked storage position  1006  to various extended positions  1008 . The present invention provides an improved cable tension release mechanism that is safer to use and more effective than the cable tension release mechanisms known in the art. The present invention permits a user to control the tension and movement of the cables  360 . As a result, the locking pins stay in place and the deck  100  transitions more smoothly and accurately. The cable tension release mechanism will be discussed below in greater detail. 
   Referring now to  FIGS. 3A-3B ,  FIG. 3A  illustrates one embodiment of a mounting strap  220  attached to a plurality of bottom rails  240 . The mounting straps  220 , in one embodiment, are solid, rectangular metal bars. Preferably, a roll-out cargo bed  1000  comprises three mounting straps  220 : a back mounting strap  220 , a middle mounting strap  220 , and a front mounting strap  220 . The strap  220  as represented in  FIG. 3  is from an end view as if the viewer is looking from the back of the truck bed  1002  toward the front. 
   In one embodiment, the bottom rails  240  are securely welded to the straps  220 . As mentioned, the mounting straps  220  may vary in size depending on the size of a particular vehicle. The mounting bar(s)  220  may rest against the floor of the truck bed  1002 , and in certain embodiments, are fastened to the truck bed  1002  with bolts. Accordingly, the front and middle straps  220  may have holes  222  to receive bolts. In one embodiment, the back strap  220  does not include holes  222 , because the weight of the deck  100  in an extended position  1008  presses the back strap  220  down against the bed of the truck  1002 , thereby reducing the need for additional fasteners. However, holes  222  may be included in the back strap  220  as well in certain embodiments. 
   The back strap  220  may further include one or more flat bars  221  welded between the bottom rails  240  and the mounting strap  220  ( FIG. 2 ). The flat bar may serve as an intermediate layer or spacer to stabilize the roll-out cargo bed  1000 . Also, if a truck has a raised tailgate  1004  or a tailgate  1004  that angles upward, the flat bar lifts the roll-out cargo bed  1000  above the tailgate  1004 . Consequently, the deck  100  rolls out and slightly angles up, thereby avoiding contact with any part of the truck. Also, the weight of the items on the deck  100  does not cause the deck  100  to tip downward because of the slight upward angle. In one embodiment, the flat bar has dimensions of about 3½ by 2¼ by 2 inches. 
     FIG. 3B  illustrates in greater detail the characteristics of one embodiment of a bottom rail  240 . The roll-out cargo bed  1000  may comprises a plurality of bottom rails  240 . In one embodiment, the roll-out cargo bed  1000  comprises a right rail  240  and a left rail  240 . Slots  242 , holes  244 , and holes  246  represent those as viewed by looking at the interior side of the rails  240 . 
   The bottom rails  240  may be hollowed-out tubes that permit bearings connected to the top rail  260  to roll inside the bottom rails  240 . Slots  242  allow the bearings connected to the top rail  260  to traverse the length of the bottom rail  240 . The slots  242  may cover about ⅔ the length of the rails  240  to enable extension of the deck  100  ( FIG. 1 ). The holes  244  permit bolts to secure bearings  250  in the bottom rail  240 . The oblong holes  246  are configured to receive pins configured to extend through the top rail  260  and the bottom rail  240 , thereby locking the rails  240 ,  260  together. 
   When the pins are locked in the holes  246   a , the roll-out cargo bed  1000  is in a storage position  1006 . When the pins are locked in the holes  246   b  and  246   c , the roll-out cargo bed  1000  is in a midway extended position and a fully extended position  1008  respectively. The pins, in one embodiment, are connected to cables  360  that are controlled by the pulley assembly  300 . The pins may extend through designated holes in the top rails  260  and through the holes  246  in the bottom rails  240 . 
     FIG. 3C  illustrates a cross-sectional view of a bottom rail  240  with a slot  242 . The bearing  250  preferably fits inside the hollowed section. In one embodiment, the roll-out cargo bed  1000  comprises eight bearings  250 : two bearings  250  connected to each top rail  260  and two bearings  250  connected to each bottom rail  240 . In a storage position  1006 , the four bearings  250  in the top rails  260  are located near the front of the truck while the four bearings  250  in the bottom rails  240  remain in a fixed position near the back of the truck. The bearings  250  in the top rails  260  roll on the inside of the hollow tube of the bottom rail  240  when transitioning from a storage position  1006  to an extended position  1008 . 
   The bearings  250  in the bottom rails  240  may be fastened or bolted to the bottom rails  240 . Each rail  240  may comprise two bearings  250 . In one embodiment, the top side of the bottom rail  240  includes a slot  252  to permit the bearings  250  to roll on the interior side of the top rail  260 . Accordingly, the center of the bearings  250  may be located slightly above the center of the bottom rail  240  as illustrated such that the bearings  250  may extend above the top surface of the bottom rail  240 . The bearings  250  may be secured with bolts and nuts. In one embodiment, the nuts may be welded to the inside of the bottom rails  240 . In one embodiment, the bearings  250  may have a diameter of about 1.653 inches and a width of about 0.508 inches and may be made of steel. In one embodiment, standoffs may be used with the bolts. 
   The top rails  260  may be substantially L-shaped and may be situated on top of the bottom rails  240 . Accordingly, the length of the top rail  260  may correspond to the length of the bottom rail  240 . As mentioned, the top rails  260  may ride on top of bearings  250 . The bearings  250  connected to the top rail  260  are preferably located near the front end of the rail  260  near the cab  1012 , thereby enabling the bearings  250  to roll within the hollow bottom rail  240 . Because the bearings  250  are securely attached to the top rail  260 , the deck  100  may roll to an extended position without rolling off of the bottom rails  240 . 
     FIG. 3D  illustrates one embodiment of a top rail  260  with holes  262 ,  264 . In one embodiment, a bearing hole  262   b  closest to the cab  1012  on each top rail  240  is preferably offset slightly from the bearing hole  262   a  to allow the bearings  250  to maintain constant contact with the bottom rails  240  during transition. The offset bearing  250  prevents the deck  100  from tipping downward in the extended position  1008 . In one embodiment, the offset bearing  250  is 1/16 of an inch higher than the rest of the bearings  250 . A hole  264  is configured to receive a locking pin. The locking pin may remain in the same hole  264  in the top rail  240  and move with the top rail  260 . 
     FIG. 4  illustrates one embodiment of the frame assembly  200  including mounting straps  220 , cross members  280 , and rails  240 ,  260 . More specifically,  FIG. 4  illustrates the location of the bearings  250  in one embodiment when the roll-out cargo bed  1000  is in a storage position  1006 . Two bearings  250   a - b  are located in the top rail  260  near the cab  1012  of the truck. Two bearings  250   c - d  are located in a fixed position in the bottom rails  240  near the tailgate  1004  of the truck. 
   The weight of the equipment  110  on the deck  100  pushes downward on the rails  240 ,  260  in the storage position  1006 . Subsequently, the bearings  250   a - b  ride on the bottom interior surface of the hollow bottom rails  240  during the majority of the transition from the storage position  1006  to the extended position  1008 . Nearing the fully extended position  1008 , however, the weight of the equipment  110  on the extended deck  100  causes pressure upward on the front of the top rails  260 . Consequently, the bearings  250   a - b  of the top rail  260  roll on the top interior surface of the bottom rail  240 . 
   As a result, the bearings  250   a  near the truck cab  1012  are preferably offset to compensate for the weight and drop of the deck  100  in the extended position  1008 . Thus, the deck  100  rolls out of the truck at an angle substantially parallel to the ground without dropping significantly. The offset bearing  250   a  is preferably set about 1/16 inches above the bearing  250   b . Accordingly, the offset bearing  250   a  contacts the top interior surface of the hollowed portion of the bottom rail  240  while the bearing  250   b  continues to contact the bottom interior surface, thereby preserving the horizontal position of the extended deck  100 . 
     FIG. 5  illustrates in greater detail the frame assembly  200  of one embodiment of a roll-out cargo bed  1000  combined with the pulley assembly  300 . The pulley assembly  300  offers an improved tension release mechanism. As mentioned previously, the tension release mechanism may include the handles  120 , a pull lock knob  140 , an adjustment mechanism  310 , a square rod  320 , a bracket stop  330 , a cable sleeve  340 , a plurality of pulleys  350 , cables  360 , spring-loaded locking mechanisms  370 , and bumper stops  380 . 
   In one embodiment, a user releases the pins from the holes  246  in the bottom rail  240  by pulling on the pull lock knob  140 . The pull lock knob  140  is stopped by the U-shaped handle  120 , so the user cannot overextend the cables  360  with normal use. The pull lock knob  140  is connected to an adjustment mechanism  310  that allows the user to adjust the tension on the cables  360  if necessary. The adjustment mechanism  310  may be located near the interior side of the cross member  280   c.    
   The adjustment mechanism  310  is preferably connected to a rod. In one embodiment, the rod is a square rod  320 . The square rod  320  may be made from a hard metal such as steel or iron that does not stretch or bend easily. Accordingly, the metal rod  320  is an improvement in the art because the rod  320  replaces a large length of cable  360 , which is prone to stretch. Also, the rod  320  may be passed through one or more holes  286 . In one embodiment, a hole  286  has the same cross-sectional shape as the rod  320 . Because the metal rod  320  does not stretch or twist, the tension on the shorter length of cables  360  is more easily maintained. Furthermore, the rod  320  has a polygonal shape to catch against a similarly-shaped pull rod guide  500  as mentioned previously. Thus, the position of the rod  320  is preserved. The rod  320  does not twist or rotate. Consequently, the fixed position creates a more stable system that resists the stretching or twisting that can potentially destroy the pulley assembly  300 . 
   The metal pull rod  320  may be connected to a cable sleeve  340 . The cable sleeve  340  connects the pull rod  320  to the cables  360 . The cables  360  wrap around the pulleys  350  and connect to a spring-loaded locking mechanism  370 . The spring-loaded locking mechanism  370  controls the locking pins that insert into the holes  246 , 264  and lock the roll-out cargo bed  1000  into position. 
     FIGS. 6A-6C  illustrate in greater detail various embodiments of cross members  280 . As mentioned previously, the number of cross members  280  may vary depending on the length of the roll-out cargo bed  1000 . The cross members  280  may comprise a front cross member  280   a , middle cross member(s)  280   b , and a back cross member  280   c . The cross members  280  are preferably made from angle iron. Holes  282  permit a fastener such as a bolt to connect the front cross member  280   a  to the deck  100 . Side view  283  illustrates nuts  284  welded to the cross member  280   a . In an alternative embodiment, the holes  282  are tapped in order to eliminate the nuts  284 . 
     FIG. 6A  further illustrates the front cross member  280   a  with a plurality of pulley brackets  400  welded to it. The pulley brackets  400  are L-shaped and include a hole  402  to secure a pulley  350  to the pulley bracket  400  with a fastener such as a nut and bolt assembly. In addition, holes  403  may permit tension pins to keep cables  360  in place. 
   Also illustrated are locking pin guides  450 . The locking pin guides  450  are welded to the cross member  280   a  to guide locking pins into the holes  264  in the top rails  260  and into the holes  246  in the bottom rails  240 . The locking pin guides  450  may be rectangular in shape and may comprise a hollowed-out center for a locking pin to run through the locking pin guide  450 . Additionally, the locking pin guide  450  may include a spacer (not shown) to help position the locking pin guide  450  properly. 
     FIG. 6B  illustrates one embodiment of a center cross member  280   b . The center cross member  280   b  comprises a hole  286  configured to receive a pull rod guide  500 . The pull rod guide  500  receives a square rod  320  that is configured to keep the pulley cables  360  from twisting. The guide  500  may be made from a section of square hollow tubing as illustrated. Alternatively, the pull rod guide  500  may be any polygonal shape that corresponds to the shape of the rod  320 . Preferably, the pull rod guide  500  is welded to the cross member  280   b . The guide  500  may be inserted through the hole  286  and welded into the hole  286 . 
     FIG. 6C  illustrates one embodiment of a back cross member  280   c . The back cross member  280   c  includes holes  288  to connect a plurality of U-shaped handles  120  to the back cross member  280   c . The cross member  280   c  also has a hole  290  to permit the pull lock knob  140  to be accessed by the user. The pull lock knob  140  connects to the pulley assembly  300  to allow the user to release the pins that lock the deck  100  in position. The U-shaped handle  120  may function as a stop for the pull lock knob  140 . Consequently, the pull lock knob  140  may be located between the U-shaped handle  120  and the back cross member  280   c . The pull lock knob  140  may be inserted into the hole  290 , and then the U-shaped handle  120  may be connected over top of the pull lock knob  140 . A user may pull on the handles  120  to pull the deck  100  from a storage position  1006  to an extended position  1008 . 
     FIG. 7  further illustrates some of the components of the pulley assembly  300  of the present invention. The U-shaped handle  120  functions as a stop for the pull lock knob  140 . The adjustment mechanism  310  allows the user to adjust the tension on the cables  360  by loosening or tightening the jam nut  312 . 
   The pulley assembly  300  also includes a bracket stop  330 . The bracket stop  330  is connected to the pull rod  320  and prevents the cables  360  from retracting too far. The bracket  330  may be L-shaped and stops against the cross member  280   b . Accordingly, the pulley assembly comprises a plurality of stops. The U-shaped handle  120  prevents the cables from extending too far, and the bracket stop  330  prevents the cables from retracting too far. Thus, the tension on the cables is maintained at a constant, functional level. 
   The cable sleeve  340  is a hollow square tube that includes holes  342  to secure the sleeve  340  to the square rod  320  and to the cables  360 . The cables  360  are preferably made from stainless steel aircraft gauge braided cable, though any metal cord may be suitable. 
     FIG. 7  also illustrates an adjusted pulley angle. The pulleys  350  are placed such that the angle α is greater than about twenty degrees. In one embodiment, the angle α is about forty-five degrees. A wider angle may enable the user to pull out the locking pins with less effort. As a result, the pulley assembly  300  is easier to manipulate and control: the user applies less force to release the pins. Because the user applies less force, the assembly  300  is less likely to be disrupted or yanked out of place, a hazard that could potentially destroy the tension system. 
   Also, the improved pulley system  300  allows the locking mechanisms  370  to function more easily, consistently maintaining locking pins in the proper position. The controlled tension and regulated movement of the cables  360  prevents the pins from being knocked out of the locking pin guides  450 . 
   The pull lock knob  140  allows the user to grasp the knob  140  with a few fingers while his/her hand remains around the U-shaped handle  120 . Thus, the user can control the deck  100  with the U-shaped handle  120  and can control the release of the pins with the pull lock knob  140 . The knob  140  includes a threaded hole that enables the adjustment mechanism  310  to be connected to the pull lock knob  140 . The pull lock knob  140  may be made of aluminum. The knob  140  may also include a finger grip  144 . The finger grip  144  preferably has a diameter greater than the diameter of the hole  290  in the back cross member  280   c , so the knob  140  may not retract into the hole  290 . The hole  290  also functions as a stop in the pulley assembly  300 . 
   The adjustment mechanism  310  may comprise an all-thread member  314  that may be inserted into a threaded hole. A nut  312  may control the amount of adjustment that may be made to the cable tension. 
   Screws or other forms of fastener may connect the pull rod stop bracket  330  to the square pull rod  320  near the center cross member  280   b . To allow the bracket  330  to be secured with screws, the bracket  330  may include holes  332 . Additionally, the bracket  330  may be L-shaped and may be made from flat bar stock. The pull rod stop bracket  330  maintains the tension of the cables  360  by preventing the cables  360  from becoming too loose. Once the user releases the pull lock knob  140 , the stop bracket  330  catches on the center cross member  280   b . Thus, the cable tension remains controlled. 
   The cable sleeve  340  connects the cables  360  to the square pull rod  320 . The sleeve  340  may be made from hollow metal tubing. In addition, the sleeve  340  may include holes  342  on top to connect the sleeve  340  to the square pull rod  320  with screws. The holes  342  do not extend through the bottom of the sleeve  340 . Holes  344 , however, may extend from one side of the sleeve  340  to the other side. Holes  344  allow the braided cable  360  to run through the holes  344 . 
   The pulley bracket  400  is preferably attached to the front cross member  280   a  as illustrated in  FIG. 6A . The brackets  400  are placed a calculated distance apart from each other so the angle created between the cables  360  is greater than 20 degrees. In a preferred embodiment, the angle is about 45 degrees. The increased angle allows the user to release the locking pins with greater ease as mentioned previously. The tension release mechanism places less stress on the cables  360  and other components of the pulley assembly  300 . Consequently, the pulley assembly  300  is more durable. A nut and bolt assembly  352  may secure the pulley  350  to the pulley bracket  400 . Tension pins  404  inserted into holes  403  keep the cable  360  from slipping off of the pulley  350 . 
   A spring-loaded locking mechanism  370  may be connected to a cable  360 . When the user pulls on the pull lock knob  140 , the added tension on the cables  360  pulls the pins  372  out of the holes  246  in the bottom rails  240 . Accordingly, when the pins  372  are pulled out, the deck  100  is free to roll out to an extended position  1008 . The locking pins  372  may lock the roll-out cargo bed in a plurality of locked positions. 
   The locking pins  372  may comprise a hole  373  that extends through the locking pin  372  to receive tension pins  374 . The tension pins  374  hold the spring  375  in a wound position against the locking pin guide  450 , or locking pin sleeve. Alternatively, locking pins  372  may comprise a C-clip to replace the tension pin  374 . 
   The locking pin guide  450 , as mentioned previously, may be welded to the cross member  280   a  and may include a spacer. A washer  376  may separate the spring  375  from the tension pins  374 . The spring  375  has stored pressure pushing against the tensions pins  374 . When the locking pin  372  is released from a locking position, the pressure of the spring  375  restores the pin  372  back into a pin hole  246  in the bottom rail  240 . Additionally, the locking pins  372  may have holes  377  to allow the pins  372  to be connected to the cable  360 . Furthermore, the locking pins  372  are preferably made of stainless steel. 
     FIGS. 8A-8B  illustrate one embodiment of a bumper stop  380  of the damper mechanism. The bumper stop  380  prevents movement of the deck  100  during travel. The weight of the equipment  110  on the deck  100  and the movement of the truck cause the deck  100  to rock back and forth, causing the components of the frame assembly  200  to hit against each other. The bumper stops  380  lessen the sound and vibration caused from the impacts. The bumper stops  380  are preferably made of vulcanized rubber or a similar resilient material. In one embodiment, a vibration dampener  381 , such as those used as feet on washers or refrigerators, comprises the bumper stop  380  of the present invention. 
   The bumper stops  380  function when the deck  100  is locked in the storage position  1006 . Preferably, the bumper stops  380  are connected to a mount  382  that is welded to the bottom rail  240 . The mounts  382  may be L-shaped and may be made of angle iron. A mount  382  may be connected to the front end of a bottom rail  240  such that the back of the bumper stop  380  faces the cab  1012  of the truck. The mount  380  is preferably welded between the front end of the bottom rail  240  and the front pin hole  246   a  in the bottom rail  240 . Thus, when the deck  100  is in a locked storage position  1006 , the top rail  260  is tight against the bumper stop  380 . The bumper stop  380  prevents movement of the deck  100  and frame assembly  200 . 
     FIG. 9B  illustrates one manner of mounting the bumper stop  380  to the mount  382 . A screw or a bolt  385  may extend through a threaded standoff  386  to connect to the vibration dampener  381 . A jam nut  387  may be included to secure the vibration dampener  381 . 
   Thus, a user pushes the deck  100  tightly against the bumper stops  380  to lock the deck  100  in the storage position  1006 . Because the stops  380  are made of rubber, the stop  380  gives just enough for the locking pins  272  to lock into place in the holes  246   a . Once the pins  272  are in place, the rubber bumper stops  380  maintain pressure against the deck  100 , thereby putting pressure on the pins  272 . The pins  272  are consequently locked tightly into position. The stops  380  accordingly minimize the movement and noise caused by the deck  100 . 
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.