Abstract:
A flexible cargo bed tie-down system that allows the user to easily change, adjust, customize, and adapt his or her vehicle to specific needs at any given moment, and that interfaces with the rest of the vehicle in an optimum manner from a functional, structural, and aesthetic standpoint. Tie-down track(s) are provided that are integral with the body of the vehicle such that the exterior contour of the track(s) do not extend appreciably beyond the contour of the adjacent portions of the body. This permits the track(s) to blend in with the body of the vehicle, which improves functionality because the track(s) do not obstruct the placement of items on the vehicle. The track(s) are provided with a predetermined region that provides for controlled deformation of the vehicle body in case of a collision.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 09/874,979, entitled “Flexible Truck Bed Tie-Down System”, filed Jun. 7, 2001. Accordingly, this application is also entitled to the benefit of U.S. Provisional Patent Application Serial No. 60/242,724 entitled “Flexible Truck Bed Tie Down System and Gate Extender,” filed Oct. 25, 2000. The entire contents of this provisional application are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of vehicles. More specifically, the present invention relates to a flexible tie-down system for vehicles. 
     The explosion in the popularity of pick-up trucks and/or sport utility trucks (SUTs) has fueled a proliferation of new body configurations. Trucks are offered as standard cabs, king cabs, crew cabs, SPORT TRACS, and the like. Likewise, truck interiors have been adapted to meet the needs for more comfort, more passenger capacity, and the like. One area of the pick-up truck that has yet to undergo a similar evolution is the cargo bed itself. 
     It is ironic that the most utilitarian element of what is essentially a utilitarian vehicle is, in practical terms, not especially useful. As currently conceived, the standard full-sized pick-up bed is little more than a large empty volume with a few tie-down points scattered along the perimeter of its interior walls or along a bed rail. There is an enormous opportunity to improve the utility and ease of use of a truck bed. 
     Some trucks are used primarily for work and others primarily for recreation. Many trucks do double-duty supporting both of these spheres of activity. One of the most glaring deficiencies of current bed design is that they are not readily adaptable to the wide variety of applications required by the end user. A truck bed should be able to support and accommodate the very different requirements that are associated with a diverse range of activities. 
     Generally speaking, bed usage may be grouped into three broad categories: hauling, securing, and separating items in the payload. Most truck users need to perform each of these tasks with some frequency. Yet the demands placed on the bed for hauling are significantly different from those needed to secure or separate items in and around the bed. 
     When hauling yard waste, plywood, recreational gear, and other items, the ideal condition is to maximize the interior volume of the bed and to maintain an easily accessible loading surface. When securing individual objects in the bed, such as dirt bikes, ATVs, air tanks, furniture, and other items, the ideal condition is to have multiple sturdy tie-down points in close proximity to the object being secured. When hauling and securing combinations of items—heavy objects and fragile equipment, for example—it becomes necessary to separate these items from one another. 
     This situation has led to a brisk business in after-market systems created by after-market manufacturers. However, while many of these systems are at least partially effective, they are not necessarily designed to interface with the truck in an optimum manner from a functional, structural, and aesthetic standpoint. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a truly flexible cargo bed tie-down system that allows the user to easily change, adjust, customize, and adapt his or her vehicle to specific needs at any given moment, and that interfaces with the rest of the truck in an optimum manner from a functional, structural, and aesthetic standpoint. 
     An important feature of the invention is that, in the invention, tie-down track(s) are provided that are integral with the body of the truck such that the exterior contour of the track(s) do not extend appreciably beyond the contour of the adjacent portions of the body. This permits the track(s) to blend in with the body of the truck, which improves functionality because the track(s) do not obstruct the placement of items on the truck. This also permits the portions of the body of the truck that support the tracks(s) to be specifically designed to take large loads, which thus allows the track(s) to support, separate and/or secure large loads. This is in contrast to currently available after-market products which sit on top of the body of the truck. Such after-market products and existing trucks are not necessarily designed to interface in an optimum manner, from a functional, structural and aesthetic standpoint. 
     Another important feature of the invention, is that the tie-down track(s) may be configured to deform at a predetermined region thereby permitting for controlled deformation of the body in case of a collision. According to one embodiment of the invention, the deformation region may include a region of the track having a reduced cross-sectional area. In another embodiment of the invention, the defromation region may include a gap between two portions of the track. In either of the aforementioned embodiments, an insert may be located in the deformation region to facilitate movement of a tie-down connector along the track. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in further detail below in conjunction with the following drawings: 
     FIG. 1 is an end view of a truck embodying the invention. 
     FIG. 2 is a sectional view of plane  2 — 2  of FIG.  1 . 
     FIG. 3 is a sectional view of plane  3 — 3  of FIG.  1 . 
     FIG. 4 is a sectional view of plain  4 — 4  of FIG. 1 (with a tie-down fitting installed). 
     FIG. 5 illustrates an example of a tie-down fitting. 
     FIG. 6 illustrates another example of a tie-down fitting. 
     FIG. 7 illustrates an example of a tire cradle. 
     FIG. 8 illustrates an example of a tank fitting. 
     FIG. 9 illustrates an example of a cargo net arrangement. 
     FIG. 10 illustrates an example of a cargo divider. 
     FIG. 11 illustrates an example of a foldable storage box in a stored position. 
     FIG. 12 illustrates the foldable storage box being placed in the storage position. 
     FIG. 13 illustrates the foldable storage box in the storage position. 
     FIGS. 14 through 17 illustrate an example of a tailgate extender, having a track, in four different positions. 
     FIG. 18 illustrates an example of an arrangement of crossbar members. 
     FIG. 19 illustrates an example of a pulley arrangement supported by the crossbar members. 
     FIG. 20 illustrates one possible configuration of a track and fittings on a crossbar member. 
     FIG. 21 illustrates a sectional view of plane  21 — 21  of FIG.  20 . 
     FIG. 22 illustrates an example of a storage box for storing tie-down fittings and/or other items. 
     FIG. 23 is a sectional view of the storage box of FIG.  22 . 
     FIG. 24 is an example of another arrangement of tracks, according to the invention. 
     FIG. 25 is an example of another arrangement of a track, according to the invention. 
     FIG. 26 is an example of another arrangement of tracks, according to the invention. 
     FIGS. 27 through 31 illustrate a type of fitting that may be used according to the invention. 
     FIGS. 32 through 34 illustrate another type of fitting that may be used according to the invention. 
     FIG. 35 is a perspective view of a track according to an embodiment of the present invention. 
     FIG. 36 is a perspective view of a vehicle bed according to an embodiment of the invention. 
     FIG. 37 is a partial perspective view of the interior view of a vehicle bed according to an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 illustrates an end view of a truck  100  configured in accordance with one embodiment of the invention. 
     As shown in FIG. 1, the truck  100  has a cargo bed, or area,  110  behind a cab (or passenger compartment)  120 . There are two sidewalls  122 ,  124  on the sides of bed  110  and front wall  125 . In this particular configuration, the truck  100  also includes a tailgate  130 . Tracks  141  and  142  are located in bed  110 . The left sidewall  122  has a track  143  which opens inward and another track  144  which opens upward. Similarly, sidewall  124  has an inward facing track  145  and an upward facing track  146 . A rearward facing track  147  is located on front wall  125  behind cab  120 , and the free end of tailgate  130  includes a track  148 . 
     FIG. 2 is a sectional view of plane  2 — 2  of FIG.  1 . FIG. 2 illustrates track  141  recessed in bed  110 . The track  141  is in the shape of a channel and has two inward turning lips  141 A and  141 B. The track  141  is provided with a slot opening S. The design of track  142  (with respect to bed  110 ) is similar to the design of track  141 . 
     FIG. 3 is a sectional view of plane  3 — 3  of FIG.  1 . As shown in FIG. 3, track  148  is located on the free end of tailgate  130 . Track  148  has inward turning lips  148 A and  148 B and a slot opening S. 
     FIG. 4 is a sectional view of plane  4 — 4  of FIG. 1, with a tie-down fitting installed. As illustrated, track  145  faces inward and track  146  faces upward. The design of tracks  145  and  146  is similar to the design of tracks  141  and  148 , as discussed above. Similarly, tracks  143  and  144  are similar to tracks  145  and  146 . 
     An important feature of the invention is that the tracks are outside of the passenger compartment (in the FIG. 1 embodiment the tracks are behind the passenger compartment). This allows the storage of larger, heavier loads. Another important feature of the invention is that the tracks  141  to  148  are integral with the body of truck  100  such that the exterior contours of the tracks do not extend appreciably beyond the contour of adjacent portions of the body. 
     For example, the exterior contour of track  141  is flush with cargo bed  110 . In FIG. 3, the upper horizontal surface of track  148  is flush with the uppermost portion  132  of tailgate  130  and the surface  148 C of track  148  is flush with the surface  134  of tailgate  130 . Similarly, as shown in FIG. 4, the exterior contours of tracks  145  and  146  do not extend appreciably beyond the contour of adjacent portions of the body. 
     This design permits the tracks to blend in with the body of the truck, which improves functionality because the tracks do not obstruct placement of items into or on the truck. Also, in the invention, the portions of the body of the truck that support the tracks are specifically designed to accommodate the tracks and to take large loads, which thus allows the tracks to support or secure large loads. As discussed above, this is in contrast to currently available after-market products which sit on top of the body of the truck. Such after-market products and existing trucks may not necessarily be designed to accommodate each other in an optimum manner, from a structural viewpoint. 
     The contour of the adjacent portions of the body of the truck can be formed by, for example, structural steel, aluminum and other material that forms part of the structural part of the body, sheet metal, sheet aluminum or other material, and/or plastic (either separate or with a track encapsulated). The track slots can be pointed in any direction, for example, upward, downward, outboard, inboard, rearward, forward, or at an angle. Also, when the tracks are not in use, the tracks can be covered with a protective strip of, for example, rubber or plastic, which fits into the slot opening. 
     In this particular embodiment of the invention, the geometry of the tracks is similar to the geometry of channels manufactured for industrial framing applications (for example for supporting pipes and electrical lines). This allows a user to employ a wide variety of commercially available fittings to customize and adapt the tie-down arrangement to the particular task at hand. 
     FIGS. 4 and 5 illustrate an example of a tie-down fitting  210 . Fitting  210  may be used with rope, straps, and the like to secure items in and/or to the bed. This fitting  210  has three separate parts, a nut  212  available from (for example) the manufacturers listed below, a male threaded commercially available eye  214 , and a washer  216 . The nut has two grooves  212 A and  212 B that are intended to mate with the in-turned lips of the track (such as lips  145 A and  145 B of track  145 ). In this embodiment, washer  216  has a metal portion  216 A and an elastic portion  216 B. This fitting can be moved anywhere along a track and then fixed in a desired location. The fitting can also be released from the track, for example, by twisting or unscrewing the fitting and then removing the fitting in a direction approximately perpendicular to the track. Providing fittings that can be inserted anywhere along the track and that are movable within the track allows the user to customize and adapt the truck to the task at hand by providing the appropriate number and spacing of fittings required for the task at hand. Also, because the fittings are releasable, they can be removed when not needed, so that they do not become an obstruction. 
     To use the assembly, the nut  212  is placed into the channel (or track), the washer  216  is placed on a threaded part of the eye  214 , and then the nut  212  is turned 90 degrees such that the grooves  212 A,  212 B in the nut mate with the in-turned lips  145 A and  145 B of the channel. Then, the eye is screwed into the nut until tight. This squeezes the track between the nut and the washer/eye assembly. The pressure locks the entire assembly to the track. The fitting is removed by loosening the nut/eye assembly, and turning the nut 90 degrees. 
     FIG. 6 illustrates another example of a tie-down fitting  310 . This fitting  310  can be used for securing a wide variety of items to a track. As shown in FIG. 6, fitting  310  includes a commercially available nut  312 , a knob portion  314 , a plastic or steel washer  315 , and a washer  316 . A contact portion  314 A of knob  314  is designed to hold an object between contact portion  314 A (and washer  315 ) and a track. The washer  316  is bonded to the nut  312  and rests on top of the track to keep the nut from falling into the track. An example of use of such a fitting will be described in further detail below in conjunction with FIGS. 10,  20  and  21 . 
     FIG. 7 illustrates an example of a specialized fitting  400  having a tire cradle  410  for use with the track system described above. This fitting  400  can be positioned and then secured, for example, to track  147  on front wall  125  behind the cab using fittings  420  and  430 . Fittings  420  and  430  are similar to fitting  210 , described above. Two straps  411  and  413  are used to secure a tire within the cradle  410 . This tire cradle can be used with the other fittings described in this patent specification to provide numerous tie-down points to stabilize, for example, a mountain bike or motorcycle, within the cargo bed. 
     It will be appreciated that the fittings described in this patent specification can be used in conjunction with, for example, ropes, straps, rubber tie-downs, and the like, to secure objects to tie-down points throughout the cargo bed. 
     FIG. 8 illustrates an example of a tank fitting  510  for use, for example, with the side tracks described above. Fitting  510  includes two commercially available bands  512  and  514  which are approximately in the shape of a quarter circle. The bands are joined at one end by a tightening assembly, such as a threaded knob  516 . The other ends of the bands are shaped to lie within one of the tracks (for example, track  145 , as shown in FIG.  8 ). Such fittings allow adjustable and secure placement of, for example, scuba tanks, and the like, near the bed perimeter. 
     FIG. 9 illustrates an example of a cargo net arrangement  600 . Arrangement  600  includes a cargo net  610  which is secured to tracks  141 ,  142 , and  148  using fittings  622 ,  624 ,  626 , and  628 . Fittings  622 ,  624 ,  626 , and  628  are similar to fitting  210 , shown in FIG.  5 . 
     The tracks at the side of the bed and/or the tracks at the bottom of the bed, can also be used to secure a cargo divider, as shown in FIG.  10 . FIG. 10 illustrates a cargo divider  710  secured to tracks  141 ,  142 ,  144 , and  146  using fittings  722 ,  724 ,  726 , and  728 . Fittings  722 ,  724 ,  726 , and  728  are similar to fitting  310 , shown in FIG.  6 . 
     FIGS. 11 to  13  depict a folding/stowable box arrangement  800  which is provided by the invention. FIG. 11 illustrates an example of the box in the storage position. When not in use, a lid  810  of the box and a rear side  820  of the box are folded together and are stored flat against the front wall  125  of the cargo bed to maximize bed space, as shown in FIG. 11 (in FIG. 11, the lid  810  is hidden behind the side  820 ). When the user desires to place the box in the storage position, both the lid  810  and the rear side  820  are moved rearward using fittings  822  and  826  to guide the side  820  and maintain the side  820  approximately perpendicular to the cargo bed. Then, knobs  824  and  828  are tightened to secure fittings  822  and  826  to tracks  145  and  143 . Then, lid  810 , which is stored in slots  821  of side  820  (lid  810  is not shown in FIG. 12 in order to show slot  821  clearly), is pivoted, for example by a hinge, to cover the interior of the box, as shown in FIG.  13 . 
     FIGS. 14 through 17 illustrate an example of a tailgate extender  900 , having a crossbar member  948 , in four different positions. As shown in these figures, the tailgate  130  is positionable such that the primary plane of the tailgate  130  is either vertical (FIG. 14) or horizontal (FIGS. 15 to  17 ). Crossbar member  948  runs in a direction perpendicular to the longitudinal direction of the truck. A first member  952  and a second member  954  are connected to the crossbar member  948 . The first member  952 , the second member  954 , and the crossbar member  948  lie in the same plane. 
     A connection assembly (to be described below) connects the crossbar member  948  to the tailgate  130  via at least the first and second members  952  and  954  such that: 
     (1) the first member  952 , the second member  954 , and the crossbar member  948  lie in the primary plane of the tailgate  130  to act as an upright for loads when the tailgate  130  is vertical (as shown in FIG.  14 ); 
     (2) the first member  952 , the second member  954 , and the crossbar member  948  lie in the primary plane of the tailgate  130  to act as an extension of the tailgate  130  for longer loads when the tailgate  130  is horizontal (as shown in FIG.  15 ); 
     (3) the first member  952 , the second member  954 , and the crossbar member  948  lie in a plane perpendicular to the primary plane of the tailgate  130  to act as an upright (or rear support) when the tailgate is horizontal (as shown in FIG.  16 ); or 
     (4) the first member  952 , the second member  954 , and the crossbar member  948  lie in a plane perpendicular to the primary plane of the tailgate  130  to act as a step when the tailgate  130  is horizontal (as shown in FIG.  17 ). (Also, the tailgate extender can be positioned as shown in FIG. 17, except with the tailgate closed, to provide another configuration, for example, for storing long objects). 
     The first and second members  952  and  954  can be stored within the tailgate  130  by pushing them into the tailgate (in which case the crossbar member  948  simply acts as a track on the free end of the tailgate similar to track  148  in FIG.  1 ). The first and second members  952  and  954  are secured to the tailgate  130  in one of the three relative positions by: (1) sliding the first and second members  952  and  954  into one pair of holes  962  and  964  which are parallel to the primary plane of the tailgate and securing the members by pins  932  and  934 ; or (2) sliding the first and second members  952  and  954  into one pair of holes  961  and  963  which are perpendicular to the primary plane of the tailgate  130  and securing the members by pins  932  and  934 . Pins  932  and  934  go through holes in tailgate  130  and members  952  and  954 . 
     FIGS. 18 and 19 illustrate an example of an arrangement  1000  of crossbar members  1100  and  1200  that can be, used to support, for example, ladders, plastic pipe, a large sea kayak, and other long objects. These crossbar members allow the cargo bed  1010  to be free for other gear. In addition, the longitudinal spacing of the crossbar members  1100  and  1200  can be adjusted to secure tall objects (such as appliances) between the crossbar members. (One way of securing such crossbar members to the tracks will be described below in connection with FIGS. 20 and 21.) 
     The crossbar members  1100  and  1200  can support, for example, a beam  1310  that can be cantilevered near the rear end of the truck to support a pulley system  1320 . FIG. 19 illustrates an example of pulley system  1320  being employed to easily load a heavy, awkwardly-sized object (wheel W) into the cargo bed  1010 . In one variation, upward facing tracks  144  and  146  may be eliminated and crossbar members  1100  and  1200  are secured to inward facing tracks  143  and  145 . 
     FIG. 20 illustrates one possible configuration of a track  1410  and fittings  1420 ,  1430 , and  1440  on a crossbar member  1400 . Fittings  1420 ,  1430 , and  1440  are commercially available from various industrial framing manufacturers (listed below). As described above, one of the advantages of the invention is that a vehicle owner may use a wide variety of readily available fittings, in conjunction with the track system, to customize his or her truck and adapt the truck to the owner&#39;s particular requirements at hand. It will be appreciated that other types of fittings, which include additional tracks, can be provided. 
     FIG. 21 illustrates a sectional view of plane  21 — 21  of FIG.  20 . As shown in FIG. 21, crossbar member  1400  is secured to track  144  by securing a horizontal portion  1450  of crossbar member  1400  to the track using a knob fitting  1460  and a nut  1470 . A suitable design for such a fitting is illustrated in FIG.  6 . 
     FIGS. 22 and 23 illustrate an example of a storage box  1500  in an outer side panel of a truck for storing fittings and/or other items. The box  1500  is supported by a slide  1510 . 
     FIG. 24 is an example of another arrangement  1600  of tracks, according to the invention. As illustrated in FIG. 24, arrangement  1600  includes tracks  1610 ,  1620 ,  1640 , and  1650  mounted to the inner sidewall of a cargo bed  1680  such that the exterior contours of these tracks do not extend appreciably beyond the contour of the adjacent portions of the body. Similarly, track  1630  is mounted to the front wall of cargo bed  1680  such that the exterior contours of the track do not extend appreciably beyond the contour of the adjacent portions of the body. 
     FIG. 24 also illustrates tracks  1660  and  1670  which project approximately one inch above cargo bed  1680 . Thus, tracks  1660  and  1670  do extend appreciably beyond the contour of adjacent portions of the body. FIG. 24 illustrates that tracks according to the invention (tracks  1610 ,  1620 ,  1630 ,  1640 , and  1650 ) may be mounted on the same vehicle which also has tracks ( 1660  and  1670 ) which do extend appreciably beyond the contour of the adjacent portions of the body. 
     FIG. 25 is an example of another arrangement  1700  of a track  1710 , according to the invention, that does not extend appreciably beyond the contour of adjacent portions  1720  of the body. 
     FIG. 26 is another example of another arrangement of tracks  1800 , according to the invention. As shown in FIG. 26, the arrangement includes a number of body panels,  1810 ,  1820 ,  1830 ,  1840 , and  1850 . The body panels are joined, for example, by fasteners  1862 ,  1864 , and  1866 . Tracks  1872  and  1874  are mounted to the body panels by, for example, welds  1871 ,  1873 ,  1875 , and  1877 . The tracks can be connected to the body by other means, such as bolts. As shown in FIG. 26, the tracks  1872  and  1874  are mounted to the panels such that the exterior contours of tracks  1872  and  1874  do not extend appreciably beyond the adjacent portions of the body. In the most preferred embodiment, the exterior contours of the tracks are substantially flush with the adjacent portions of the body. However, the exterior contours of the track can extend up to one-eighth of an inch beyond the adjacent portions of the body, one-quarter of an inch beyond the contour of the adjacent portions of the body, or up to one-half of an inch beyond the contour of the adjacent portions of the body. 
     An alternative embodiment of a track according to the present invention is shown in FIG.  35 . As shown in FIG. 35, the track  350  includes a deformation region  354 . The deformation region  354  is provided to decrease stiffness and therefore permit controlled deformation of the cargo bed. If the vehicle is involved in a collision, the tie-down tracks installed in the cargo bed provide reinforcement and reduce the amount of energy absorbed by the vehicle body. This embodiment of the present invention provides a tie-down track with reduced stiffness and increased energy absorption. The location of the deformation region is predetermined to provide for controlled deformation and energy absorption by the vehicle body. 
     The track  350 , shown in FIG. 35, is provided with the predetermined deformation region  354  so that when sufficient load is applied to the track  350 , the track deforms. In one exemplary embodiment, the deformation region  354  is a gap between a first portion  351  and a second portion  355  of the track. The gap may be configured to include an insert  353 . The insert  353  may be formed to have the same cross-sectional configuration of the track portions  351 ,  355 . Alternatively, the insert  353  may have a slot opening where the inwardly turning lips of the channel are omitted, such as shown in FIG. 35, to facilitate insertion and removal of a fitting, for example. The provision of the slot without lips may also serve to prevent the deformation region  354  from being used as a tie-down point, because a fitting cannot be secured to a track without the inwardly turning lips. Alternatively, the deformation region may include a wider slot to prevent the use of the region as a tie-down point. 
     FIG. 35 is an exploded view of the track  350 , therefore, it should be noted that the insert  353  provides for a continuous surface for sliding or rolling a fitting along the track. The insert  353  is preferably formed of a material having a lower stiffness than the track portions  351 ,  353  such as plastic or sheet metal, for example. The provision of the insert  353  allows for the track portions  351 ,  355  to deform relative to one another if the vehicle is involved in a collision. The track, as shown in the figures and described herein, is described while installed in the cargo bed of a truck. However, the track  350  may be installed in any number of suitable light weight consumer vehicles having the need for tie down tracks such as, for example, SUVs, minivans, station wagons, etc. 
     The track shown in FIG. 35, may be positioned at any location throughout the vehicle bed. The track  350  may be positioned in the longitudinal direction of the vehicle along the floor or side of the cargo bed. 
     FIG. 36 discloses a track  3000  positioned along the side wall of the cargo bed. The track  3000  includes a rear portion  3010  and a front portion  3030 . The track  3000  includes a gap  3040  located between the front and rear portions of the track. The gap  3040  serves as the deformation region that reduces the stiffness of the track  3000  and the cargo bed. The provision of the gap  3040  permits the two track portions  3010 ,  3030  to move relative to one another in case of a collision or similar event applying a large force to the vehicle body. 
     FIG. 36 also discloses a track having two track portions  1660 ,  1670  and a gap  1665  located therebetween. According to the present invention, the tie-down track may include a complete gap between two track sections (e.g. gap  1665 ) or a region in which the track has reduced stiffness or strength. For example, when a channel is employed as the track, the deformation region may include a gap only in the side walls and lips of the channel with the base of the channel extending continuously from the first portion  3010  to the second portion  3030 . Furthermore, in either instance, an insert (such as shown in FIG. 35) may be provided between the two track portions. 
     According to another embodiment of the present invention, a track having a deformation region is provided in the floor of the cargo bed. As shown in FIG. 37, the floor of the cargo bed  110 , includes two tracks  300 . Each track includes two separate portions  301 ,  302  with a deformation region  304  therebetween. As mentioned above, with regard to FIG. 36, the deformation region may comprise a gap or region of reduced strength and stiffness. An insert for guiding a tie-down fitting may be included in the deformation region to facilitate sliding or rolling the fitting between the two portions  301 ,  302  of the track  300 . 
     FIGS. 27 to  31  illustrate another type of fitting  1900  that may be used. If the fittings described above in connection with FIGS. 5 and 6 are not tightened enough or if the eye (or knob) is turned, the assembly can loosen and may fall out of the track. On the other hand, if the fitting is tightened too tightly, especially in the case of an aluminum track, there could be damage or premature wear of the track. 
     The FIGS. 27-31 embodiment provides a more positive engagement with the track that does not rely as much on the user having the correct “feel” in tightening the thread/nut assembly. In this embodiment, the tie-down fitting does not clamp onto the track, but instead stays in place by a combination of a pin and a lock bar. As will be described below, this embodiment of the invention requires holes in the back side of the track(s). 
     As shown in the Figures, there are four major pieces to this design. A center shaft  1910  is provided with an eye  1920  (or other type of fitting/connection) on one end, a square shank  1930  in the middle, and a pin  1940  on the other end. Eye  1920 , shank  1930 , and pin  1940  are formed together as one piece. A rectangular lock bar  1950  is provided with a hole the same diameter as the pin end  1940  of the center shaft  1910 . A spring locking ring  1960  has a square hole to match the shank  1930  of the center shaft and includes a recessed area which houses an internal spring  1968 , notches for fingers, and a boss  1962  to engage the track opening. A set screw  1952 , or pin, secures the lock bar  1950  to the center shaft. In this particular configuration, a link  1922  is attached to the eye  1920  of the center shaft. 
     To assemble the unit, the spring  1968  is slid onto the center shaft  1910  stopping against a larger diameter near the eye end. The locking ring  1960  is then slid over the square shank  1930  of the center shaft  1910 . Then, the lock bar  1950  is installed over the center shaft pin  1910 , and is aligned so that the long side of the lock bar  1950  is perpendicular to a long side of the locking ring boss  1962  and is screwed (or pinned) in place by screw  1952 . 
     To install the fitting  1900 , the entire unit is positioned in a track  2020 , opposite a track hole  2010 , with the lock bar  1950  aligned with the track, as shown in FIG.  29 . The center shaft  1910  is pushed to overcome the spring pressure, allowing the lock bar  1950  to pass the sides of the track opening. Then, the entire unit is rotated until the boss  1962  on the locking ring  1960  aligns with the track opening and the spring forces the locking ring  1960  down against the track, as shown in FIG.  30 . This also causes the lock bar  1950  to be wedged in between the back of track  2020  and track lips  2022  and  2024  (this keeps the pin  1910  engaged in the hole  2010  and keeps the entire assembly from pulling out of the track). To remove, the thumb pushes down on the center shaft  1910  and fingers on either side of the locking ring  1960  lift the locking ring  1960  and boss  1962  away from the track opening, as shown in FIG.  31 . The entire unit is then rotated 90 degrees, allowing the locking bar  1950  to disengage from the track. 
     This embodiment thus provides an arrangement that is simple, easy to use, and provides very positive locking action. As long as the boss  1962  holds the lock bar  1950  from rotating, the only way to move or remove the tie-down fitting would require destruction or gross distortion of the track and/or tie-down fitting. 
     FIGS. 32 through 34 illustrate another type of fitting that may be used according to the invention. This type of fitting also requires tracks with holes. In this embodiment, the assembly  2100  includes a loop  2110  welded to a pin  2120  after the pin is inserted through a plastic (or metal) spring  2130  and spacer  2140 , which in turn is mechanically bonded to a rectangular metal locking bar  2150 . This arrangement allows the loop/pin assembly to spin freely with respect to spring  2130 , spacer  2140 , and locking bar  2150  at all times. A projection  2122  on the bottom of pin  2120  and a projection on the top of pin  2120  (not visible in the drawings) maintain spring  2130 , spacer  2140 , and bar  2150  on the pin (while still allowing relative rotation therebetween). 
     To use this fitting  2100 , the fitting is positioned over the track  2220  above a track hole  2210 , as shown in FIG.  33 . The pin  2120  is inserted into the hole  2210 , with the rectangular locking bar  2150  positioned to drop into the track. The spring  2130  (and therefore the locking bar  1950 ) is then twisted 90 degrees clockwise until detents  2132  and  2134  on the underside of the spring drop into the track, as shown in FIG.  34 . The tension between spring  2130  and locking bar  2150  on the track  2220  maintain the assembly in this position. 
     To remove this tie-down, the spring  2130  (and the locking bar  2150 ) is rotated counter-clockwise. 
     Numerous other types of fittings may be used with the invention, for example, supports for plate glass racks, supports for ladders, and the like. Suitable off-the-shelf fittings are readily available for strut systems and are offered by, for example, Unistrut (Wayne, Mich.); Midland-Ross Corp., Superstrut Division, (Oakland, Calif.); and B-Line Systems, Inc. (Highland, Ill.). 
     The invention is not limited to the preferred embodiments described above. For example, a track could be mounted directly to the tailgate without the use of members  952  and  954 . Variations and modifications of the invention will occur to those in the field, in light of the above teachings. The invention is therefore defined by reference to the following claims.