Abstract:
A restraint for a parked swap body container includes a face stop that can be selectively positioned to a restraining position and a release position. In the restraining position, the face stop is adapted to engage a front face of the container to limit the extent to which the parked container can move away from an edge of a truck loading dock. In The release position, the face stop allows a truck to remove the container from the loading dock. The restraint may also include a frame that can be repositioned longitudinally to accommodate containers of various lengths. A fine adjustment can be added to further limit horizontal movement of the container. And an optional bottom support could engage the bottom of the container to provide even more support.

Description:
BACKGROUND OF THE INVENTION 
     1. Field Of The Invention 
     The subject invention generally pertains to swap body containers, and more specifically, to a device that restrains a parked swap body container. 
     2. Description Of Related Art 
     A swap body is typically a large freight container having four retractable legs. The legs are usually retracted while the swap body is in transit on the bed of a truck, trailer, ship, or rail car. When parked at a truck loading dock, the legs are typically extended to support the container upon a driveway with the floor of the container generally aligned flush to the floor of the loading dock. This allows a forklift to drive into the container for loading or unloading, yet allows the truck that delivered the container to leave. 
     While the legs provide a vertical/columnar support for the weight of the container and its contents (and material handling equipment), the legs are not designed to resist substantial horizontal forces. Substantial horizontal forces, however, can be exerted on the legs. For example, if the forklift inside the container was to suddenly stop by applying the brakes or striking cargo, the horizontal reaction force would be transmitted to the container&#39;s legs. Since a forklift can weigh thousands of pounds, and given the relative instability of the legs to resist horizontal movement, it is possible that an abrupt stop or collision could cause the container to move horizontally away from the dock, opening up a potentially hazardous gap between the container and the dock. Further, such horizontal movement could place a torque or bending force on one or all of the legs, causing them to buckle, or fold up, or (in a worst-case scenario) to collapse altogether. Such an accident might seriously harm the forklift operator, others nearby, the cargo or surrounding structure. 
     One means for restraining a truck trailer atop a railroad car is disclosed in U.S. Pat. No. 4,718,800. The device includes a support plate (item 18) for engaging a kingpin that extends out from underneath the bottom of the trailer. The support plate is rather wide, possibly to accommodate a slot having a wide lead-in for catching a kingpin that may be disposed substantially off-center or difficult to see, and thus, possibly difficult to align to the slot. Moreover, with the kingpin being underneath the container, it may be difficult to visually confirm that the pin is fully engaging the plate. Of course, such a device also relies upon the presence of a kingpin to properly operate. 
     SUMMARY OF THE INVENTION 
     In order to minimize undesirable horizontal movement of a swap body, there is provided a restraint for a parked swap body container that includes a face stop that can be positioned to a restraining position or a release position relative to the front face of the container. In the restraining position, the face stop is adapted to engage a front face of the container to limit the extent to which the parked container can move away from an edge of a truck loading dock. In the release position, the face stop allows movement of the container, for example to allow a truck to remove the container from the loading dock. 
     Such a restraint helps keep a swap body container from slipping too far away from the edge of the dock, thereby possibly avoiding creating a hazardous gap between the container and the edge of the loading dock and the related undesirable forces on the legs that could lead to their failure. 
     In some embodiments, the restraint is able to be removed to a location that is completely out of the way for delivering and removing a swap body from a loading dock, or possibly for facilitating snow removal of the loading dock&#39;s driveway. 
     Some embodiments also include a fine adjustment which is advantageous in further limiting the extent to which a parked swap body container could otherwise move away from the loading dock. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a restraint engaging a swap body container that is parked at a loading dock. 
     FIG. 2 is a left end view of FIG.  1 . 
     FIG. 3 is a more detailed side view of the restraint of FIG.  1 . 
     FIG. 4 is a right end view of FIG.  3 . 
     FIG. 5 is a side view of the restraint of FIG. 3, but with the restraint in its release position. 
     FIG. 6 is a side view of another embodiment with a restraint in its release position. 
     FIG. 7 is a side view of the restraint of FIG. 6, but with the restraint in its restraining position. 
     FIG. 8 is a side view of another restraint embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2, respectively, show a side and front view of a swap body  10  parked upon a driveway  12  of a truck loading dock area  14 . Swap body  10  is primarily a relatively large freight container  16  whose length  18  from a front face  20  to a rear face  22  may exceed  23  feet and whose width  24  may be about 8 feet or more. Swap body  10  typically includes four legs  26  that can extend downward to support the weight of container  16  when parked. However, when swap body  10  is in transit on, for example, the trailer bed of a truck, legs  26  are typically repositioned for storage by being folded up underneath a bottom  28  of container  16 . When a truck delivers swap body  10  to loading dock area  14 , extending legs  26  allows the truck to leave, while container  16  may be loaded or unloaded by a forklift  30  through a user access  32 . 
     Movement of lift truck  30  inside the container, particularly quick stops and quick starts, results in forces F (FIG. 1) being exerted on the container. As legs  26  support container  16  in place, these forces F are transmitted to the legs, and can lead to torques and stresses within the legs that could lead to their failure. Use of a container restraint as disclosed herein helps support the container to minimize its movement away from the dock, and thus minimize harmful stresses on the legs. Accordingly, this problem is minimized by providing a restraint that limits the movement of container  16  away from an adjacent structure such as a loading dock by engaging a front surface of the container. 
     An example of such a restraint is shown in FIGS. 3 and 4. Here, a restraint  38  is provided with a base such as, for example, a channel  41  anchored to driveway  12  by way of anchor bolts. To prevent horizontal movement of the container  16 , a face stop  42  is coupled to the base or channel  41  so as to be movable between a restraining position (wherein the face stop  42  is disposed adjacent face  20  of container  16  to prevent or impede movement thereof) and a release position (wherein face stop  42  is disposed to not impede movement of face  20 ). The coupling between face stop  42  and base  41  is such that face stop  42  can be secured or locked into the restraining position. 
     While a face stop according to one embodiment could be directly coupled to the base (see FIG. 8, for example), the exemplary restraint according to FIGS. 3-5 shows the face stop  42  coupled to the base  41  through additional components. In particular, an engaging assembly  55  is provided, which includes face stop  42 . Engaging assembly  55  also includes a bottom support such as channel  56 , upon which face stop  42  is preferably mounted for movement, as discussed in greater detail below. Bottom support  56  also advantageously engages and supports a bottom surface  28  of container  16  when the restraint is in the restraining position, helping to give enhanced vertical stability and collapse-prevention to container  16 . 
     The coupling of face stop  42  to base  41  is achieved by virtue of engaging assembly  55  being mounted for movement relative to base  41  through a movable assembly  43 . In the restraint of FIGS. 3-5, the movable assembly is a linkage comprising arms  44 ,  46 ,  50  and  52 , each of which are pivotally mounted both to the engaging assembly  55  and to base  41 . At base  41 , arms  44  and  46  pivot together as a pair about a common axis  68 , while arms  50  and  52  also pivot as a pair about another common axis  70 . The upper ends of arms  44 ,  46 ,  50  and  52  are pivotally coupled to engaging assembly  55  at pivot points  58 ,  60 ,  62  and  64  respectively. The arms are of generally the same length and pivot in unison with each other to raise and lower engaging assembly  55  in an attitude that is generally level or parallel to base  41 . This allows face stop  42  and bottom support  56  to remain generally square to container  10 , as assembly  43  lifts assembly  55  to the restraining position. 
     In one embodiment, movable assembly  43  is moved by a powered actuator, such as a fluid actuated cylinder  66  (e.g., hydraulic or pneumatic). In this restraint, cylinder  66  extends between lower axis  70  and an upper shaft  71 . It should be appreciated, however, that cylinder  66  can be mounted in other configurations that can also forcibly pivot the arms of assembly  43 . For example, cylinder  66  can be mounted in a configuration similar to that of a manual jack  108  shown in FIG.  6 . Also, instead of a cylinder, other actuators or manual power could be used. Cylinder  66 , however, has an additional benefit of being lockable in an extended position, and thus also serves to lock face stop  42  in place relative to base  41  to further provide a restraining function. 
     While face stop  42  could be fixed relative to bottom support  56 , here an adjustment  76  advantageously mounts stop  42  for horizontal movement. Varying lengths of swap bodies could mean that a non-adjustable stop  42  could be significantly displaced from front face  20  even when in the restraining position. So the horizontal adjustment provides a way of “snugging up” or taking up the gap that might otherwise exist between stop  42  and the face of various length containers. In one embodiment, a lead screw  90  driving a nut  88  provides the horizontal adjustment. Nut  88  extends through a slot  78  to attach to face stop  42 . Lead screw  90  is rotatably supported by a bearing plate  92  at one end and driven at an opposite end by a drive  94 , such as a motor (e.g., hydraulic, pneumatic or electric). Drive motor  94  rotating screw  90  moves nut  88  to feed stop  42  linearly in a direction that depends on the motor&#39;s direction of rotation. Guide tracks  86  can be added to further guide the movement of stop  42  along bottom support  56 . 
     It should be appreciated by those skilled in the art, that the foregoing description of adjustment  76  is just one of many mechanisms available to adjust stop  42  relative to frame  40 . Therefore, adjustment  76  has been schematically illustrated to encompass those other mechanisms, examples of which would include, but not be limited to: manual actuators, hydraulic or pneumatic cylinders, linear ratchets, discrete repositionable stops, and various clamping devices. Moreover, it is well within the scope of invention to incorporate the adjustment anywhere from stop  42  to driveway  12  such as, for example, at an interface where frame  40  engages driveway  12 . 
     In the operation of restraint  38 , cylinder  66  extends to lower engaging member  55  down to a release position, possibly all the way down against driveway  12 , as shown in FIG.  5 . The low profile provides enough vertical clearance to allow a truck carrying a swap body to pass over restraint  38  with the truck&#39;s right and left wheels straddling each side. After the truck positions swap body  10  at loading dock  14 , legs  26  are extended downward to a position to support container  16  upon driveway  12 . Once swap body  10  is self-supported, the truck can depart the loading dock area. Cylinder  66  then retracts to pull the four arms of linkage assembly  43  back to a more upright position. This raises face stop  42  (here carried on engaging member  55 ) to a restraining position where channel  56  or track  86  engages the underside of container  16 , as shown in FIG. 3 and 4. Should a gap result between face stop  42  and front face  20 , adjustment  76  can drive stop  42  against face  20  to close the gap, and thus more firmly restrain container  16 . After container  16  is safely loaded or unloaded, it can be released by cylinder  66  once again lowering engaging member  55  back down to its release position, as shown in FIG.  5 . 
     In a closely related embodiment, shown in FIGS. 6 and 7, a restraint  96  includes a mobile base  41 ′ that is mountable to driveway  12 . However, retractable swivel casters  98  extending below a bottom surface  102  of base  41 ′ also allow restraint  96  to be moved in a lateral direction across driveway  12 . This allows restraint  96  to be removed from the area, so it presents no impediment to a truck delivering or removing swap body  10 . It also allows a single restraint to be used at several positions within one dock area to accommodate swap bodies of various lengths, or even moved to another dock area altogether. 
     One possible way of temporarily fixing restraint  96  to driveway  12  to allow it to perform its restraining function is by having a plug  100  protrude below surface  102  of restraint  96 , so that it extends into a socket  106  imbedded in driveway  12 . In this exemplary embodiment, casters  98  normally extended by springs  110  support base  41  ′ to elevate plug  100  above the top surface of driveway  12 . This allows positioning of restraint  96  (without plug  100  dragging against the driveway) to align plug  100  to a socket  106 . Once aligned, an actuator, e.g., manually operated jack  108 , pivots arms  104  to raise an engaging assembly  55 ′ up against container  16 . Continued jacking of assembly  55 ′ up against the bottom of container  16  forces base  41 ′ downward against the surface of driveway  12 . The forced downward motion of base  41 ′ overcomes springs  110  to retract casters  98  and force plug  100  into socket  106 , as shown in FIG.  7 . 
     If a gap remains between face stop  42  and the front face of container  16  after restraint  96  is in its restraining position (e.g., base  41 ′ is fixed relative to driveway  12 ), the gap can be reduced or eliminated by an adjustment assembly  76 .′ In this restraint, adjustment  76 ′ includes a manually operated crank  114  that operates a screw and nut combination (e.g., screw  90 ′ and nut  88 ) for feeding stop  42  in a manner comparable to that of adjustment  76 . Further, the horizontal positioning of face stop  42  could be carried out in a variety of other ways, such as those already discussed with reference to adjustment  76 . 
     To return restraint  96  to its release position, jack  108  is retracted until base  41 ′ lifts plug  100  out of socket  106 , so restraint  96  can be rolled laterally clear of container  16 . By moving face stop  42  laterally to its release position and clear of container  16 , restraint  96  does not necessarily have to collapse all the way down to driveway  12  in order for a truck to have access to deliver or remove container  16 . It should be appreciated by those skilled in the art, that although a pivoting style lifting mechanism is used to position face stop  42  in its restraining position, other mechanisms or structure could be employed such as, for example, mounting a face stop on a conventional wheeled trailer jack releasably lockable to driveway  12 . 
     As an option, in FIG. 6, socket  106  can be shielded by a sliding plunger  116  to help keep dirt from entering socket  106 . In this example, a threaded adjustment  118  helps align plunger  116  flush with driveway  12 , while a compression spring  120  allows plug  100  to still protrude into socket  106 . 
     In another embodiment, shown in FIG. 8, container  16  is restrained by a pivoting face stop  122  that is directly coupled to a base  124  anchored to driveway  12 . To restrain or release container  16 , face stop  122  pivots about a pin  125  that attaches face stop  122  directly to base  124 . In the restrain position, a brace  126 , attached to face stop  122  (either the front or back) and base  124  by way of pins  130  and  132  respectively, holds face stop  122  generally up against face  20  of container  16 . Any gap remaining between stop  122  and face  20  can be taken up by an adjustment  128 , such as, for example, a turnbuckle that varies the length of brace  126  between its mounting pins  130  and  132 . Other examples of adjustment  128  would include, but not be limited to, lead screws, hydraulic or pneumatic cylinders, linear ratchets, discrete repositionable stops, and various manual actuators or adjustable clamping devices. Of pins  130  and  132 , at least one is preferably made readily detachable or disengagable to allow face stop  122  to be quickly raised and lowered between its restrain and release position. In one exemplary embodiment, a series of holes or detents  134  provides a selection of locations at which pins  125  and  132  can be positioned to accommodate containers of various lengths. 
     To release container  16 , detachable pin  132  allows stop  122  and brace  126  to swing down and clear of container  16 . The pivoting motion can be performed manually or powered by some conventional actuator, such as those already discussed. 
     It should be noted that each restraint shown herein could also be provided with a means for sensing when the restraint is in a restraining position. Appropriate visual signals (red and green lights, etc.) or audio signals could be connected to this sensing means to give dock personnel, drivers and the like appropriate indications that the swap body either is or is not properly restrained from movement. 
     Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those skilled in the art. Therefore, the scope of the invention is to be determined by reference to the claims that follow.