Abstract:
A retractable barrier includes a rollup or otherwise retractable panel that can extend between two spaced apart support members. When not in use, the panel can retract onto one of the support members to permit passage. The barrier provides substantial impact resistance by having the reactive force of the impact transfer directly between the barrier&#39;s retractable panel and its support members without having to rely on the strength of the panel&#39;s take-up roller or the strength of the roller&#39;s anti-rotation mechanism. This can be accomplished by having a slot-engaging stop member mounted directly to the panel itself. The stop member is preferably a pipe, rod, bar or some other vertically elongate member that can broadly distribute an impact reactive force over the height of the panel. In some embodiments, the barrier can be set for various doorway widths by simply repositioning the stop member&#39;s location on the retractable panel.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The subject invention generally pertains to retractable safety barriers and more specifically to a heavy-duty barrier whose design features make it particularly suitable for impeding heaving loads such as, for example, a forklift at a loading dock platform.  
         [0003]     2. Description of Related Art  
         [0004]     Many retractable safety barriers for doorways have been developed to help prevent children and pets from entering certain areas. To selectively open or block a doorway, some barriers include a rollup panel that can be unrolled to extend across and block the doorway. When not in use or to allow passage, the panel can wrap about a roller for storage along one side of the doorway. A few examples of retractable barriers with rollup panels are disclosed in U.S. Pat. Nos. 5,636,679; 5,690,317; 6,536,502; 5,505,244; and 6,056,038.  
         [0005]     Once such a rollup panel is extended across a doorway, usually some type of locking mechanism helps prevent the panel from unwrapping any farther so that the child or pet is unable to force the panel open. Such locking mechanisms typically include a little tab or pawl that engages a ratchet or some other type of tooth or slotted wheel, which in turn is coupled to the roller about which the panel is wrapped. The tab or pawl engaging the wheel hopefully prevents the roller from releasing the panel any farther. This may work well for light duty applications involving children and pets; however, such barriers do not appear adequate for industrial applications.  
         [0006]     In factories, for example, a forklift and other material handling equipment may need to travel near operating equipment such as machine tools (machining centers, turning centers, etc.). A permanent guardrail may prevent a forklift from striking the machine, but the guardrail may also interfere with material handling equipment trying to load and unload the machine of its work pieces.  
         [0007]     Truck loading docks may also have a need for a retractable barrier. A barrier may help prevent dockworkers and material handling equipment from accidentally falling off the edge of the dock&#39;s elevated platform. The platform&#39;s height is about the same as that of an average truck bed. Although a door typically exists at the edge of the platform, the door&#39;s strength may be insufficient to withstand the impact of a forklift, or the door may be left open for various reasons. The door, for instance, may be left open simply because the weather is nice, and the workers inside would like to enjoy some fresh air. With the door open, however, the loading dock platform may create a safety problem.  
         [0008]     Although costly massive safety gates have been used at loading docks, they can take up a lot of space even when they are opened to allow passage through the doorway. Even though they may be able to stop a slowly moving forklift, an impact can cause considerable damage to the gate due to the gate&#39;s limited ability to resiliently absorb the impact. Also, permanent or other conventional guarding may not be suitable for loading dock areas, as such guarding may interfere with operating the door, loading and unloading trucks, and operating a dock leveler that may be installed at the platform.  
         [0009]     A dock leveler is often installed at the loading dock platform to compensate for a height difference that may exist between the platform and the bed of the truck. A dock leveler typically includes a deck that is hinged at its back edge to raise or lower its front edge to generally match the height of the truck bed. Often an extension plate or lip is pivotally coupled to the deck to bridge the gap between the deck&#39;s front edge and a back edge of the truck bed. The deck and extended lip provide a path for forklifts to travel between the loading dock platform and the truck bed, thus facilitating loading or unloading of the truck. Unfortunately, a conventional barrier or guardrail extending over the dock leveler may restrict the deck&#39;s upward pivotal motion.  
         [0010]     Since a dock leveler and the adjacent door move in the area where guarding may be needed, it becomes challenging to provide the area with a barrier that is movable yet sufficiently strong to impede heavy material handling equipment. Thus, a need exists for a movable, heavy-duty industrial barrier, which is more compact in its stored position, is more capable of stopping a forklift without significant damage, and incorporates a more cost-efficient design.  
       SUMMARY OF THE INVENTION  
       [0011]     In some embodiments, a retractable rollup barrier is provided with substantial impact resistance by having the reactive force of the impact transfer directly between the barrier&#39;s retractable panel and its vertical support members without having to rely on the strength of the panel&#39;s take-up roller or the strength of the roller&#39;s anti-rotation mechanism.  
         [0012]     In some embodiments, a retractable rollup barrier includes a stop member that is carried by the rollup panel itself.  
         [0013]     In some embodiments, the stop member is an elongate member, such as a pipe, rod or bar that broadly distributes an impact reactive force over the height of the rollup panel.  
         [0014]     In some embodiments, the stop member comprises multiple separate members on the same vertical line. The separate members could be a series of pipes, rods, or bars that work together to broadly distribute an impact reactive force over the height of a retractable panel.  
         [0015]     In some embodiments, a retractable rollup barrier can be set for various doorway widths by simply repositioning a stop member&#39;s location on the rollup panel.  
         [0016]     In some embodiments, the extent to which a rollup panel can extend out from within a housing is limited by a thicker section of the panel being unable to fit through a narrower slot in one of the barrier&#39;s support members.  
         [0017]     In some embodiments, a retractable panel includes reinforcing straps that greatly increase the panel&#39;s strength.  
         [0018]     In some embodiments, the reinforcing straps of the retractable panel can be of a different color than the rest of the panel so that the panel is clearly visible when in use.  
         [0019]     In some embodiments, the panel includes a large warning label that is visible from a distance so that people in the area can see that a drop-off hazard exists even though a closed dock door may disguise the danger.  
         [0020]     In some embodiments, the rollup panel does not reach its full extension from within its housing until the panel experiences an impact. This feature allows a distal end of the panel to be readily hooked or unhooked from an anchored support member without the panel having to be pulled tightly against a hard stop to do so.  
         [0021]     In some embodiments, a retractable barrier straddles a dock leveler.  
         [0022]     In some embodiments, two anchor support members of a retractable barrier can serve as bollard-like members for protecting the lateral edges of a door from damage.  
         [0023]     In some embodiments, a distal end of a retractable panel can retract and stow within a pocket of a support member housing to protect the distal end from damage and avoid interfering with traffic when the retractable barrier is not in use.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a perspective view of a retractable barrier in an open or stored position.  
         [0025]      FIG. 2  is a perspective view of the retractable barrier of  FIG. 1  but showing the barrier partially open.  
         [0026]      FIG. 3  is a perspective view of the retractable barrier of  FIG. 1  but showing the barrier in a blocking position.  
         [0027]      FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 1 .  
         [0028]      FIG. 5  is a cross-sectional view taken along line  5 - 5  of  FIG. 3 .  
         [0029]      FIG. 6  is a cross-sectional view similar to  FIG. 5  but showing the panel experiencing an impact.  
         [0030]      FIG. 7  is a cross-sectional view similar to  FIG. 5  but with the barrier being set for a narrower doorway.  
         [0031]      FIG. 8  is a cross-sectional view similar to  FIG. 5  but with the location of the barrier&#39;s two support members being interchanged. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]     A retractable safety barrier  10  primarily intended for heavy duty industrial use is shown in  FIGS. 1-3 . The drawing figures show a view from within a building looking out through an open doorway  12 .  FIG. 1  shows barrier  10  in an open stored position,  FIG. 3  shows barrier  10  in a blocking position, and  FIG. 2  shows barrier  10  partway between its open and blocking positions.  
         [0033]     Although barrier  10  is particularly suited for installation on an elevated platform  14  of a loading dock  16 , barrier  10  can be readily applied to a broad range of heavy and light duty applications including, but not limited to, guarding machinery, guarding construction sites, restricting vehicular and pedestrian traffic, restraining cargo, restraining stock stored on high pallet racks, etc. Since the structure and function of various embodiments of barrier  10  may be similar regardless of the barrier&#39;s specific application, barrier  10  will be described with reference to its installation at loading dock  16 .  
         [0034]     Loading dock  16  may include a conventional dock leveler  18  whose pivotal deck  20  is presently shown at its cross-traffic position where the top surface of deck  20  is generally flush with platform  14 . Dock  16  also includes a door  22  that can provide access to a truck parked at the dock. When a truck is not present, door  22  is normally closed and the need for barrier  10  may not be apparent; however, the strength of door  22  may be insufficient to withstand the impact of a forklift. In some cases, door  22  may be left open, as shown, even though no truck is present. If the weather outside is mild, for instance, door  22  may be left open to help ventilate the building.  
         [0035]     Whether door  22  open or closed while no truck is present at the dock, platform  18  may create a falling hazard. A dockworker or material-handling vehicle, such as a forklift, may accidentally travel off the edge of platform  14  and fall onto the driveway just beyond doorway  12 . To help prevent such an accident, some type of barrier could be installed across the doorway. The barrier, however, would need to be movable to permit loading or unloading a truck at the dock, not interfere with the operation of the door, permit the operation of the dock leveler, and not obstruct traffic in the vicinity of the dock.  
         [0036]     To accomplish all of this, barrier  10  comprises a retractable panel  24  that can selectively extend and retract between two support members, which will be referred to as a first support member  26  and a second support member  28 . Support members  26  and  28  may be attached to the floor of platform  18 , attached to the wall of a building, and/or connected to adjacent structure (e.g., a doorway frame, door guide, etc.), wherein the adjacent structure is in turn attached to the building wall or the floor. In some cases, support members  26  and  28  are self-supporting members, wherein the members  26  and  28  are able to self-support their upper ends by simply having their lower ends be anchored to the floor. Members  26  and  28  could also be self-supporting in other ways, such as by being fixed to a structural member besides the floor, such as a wall adjacent the door opening. In some cases, support members  26  and  28  may be referred to as a “post,” wherein the term “post” refers to a member whose primary source of support comes from the floor. In a currently preferred embodiment, the “retractable” feature of panel  24  is provided by panel  24  being a pliable roll-up panel that retracts by wrapping about a roller  30 , wherein roller  30  is just one example of a take-up member. Other methods of retracting a panel include, but are not limited to, folding or translating interconnected sections of the panel.  
         [0037]     When panel  24  is pulled out from within first support member  26  and coupled to support member  28 , as shown in  FIGS. 3 and 5 , panel  24  provides a barrier that helps prevent people and vehicles from accidentally falling off the edge of platform  14 . When panel  24  retracts to its stored position of  FIGS. 1 and 4 , barrier  10  permits normal operation of the loading dock.  
         [0038]     For the illustrated embodiment, of  FIG. 3 , panel  24  comprises a fabric web  32  reinforced by one or more straps  34  made nylon or some other a high-test belting material. A proximal end  36  ( FIG. 5 ) of panel  24  connects to roller  30 , and a distal end  38  of panel  24  can be selectively stored within a pocket  40  of first support member  26  or releasably coupled to second support member  28 .  
         [0039]     In some cases, referring to  FIG. 5 , first support member  26  comprises a housing  42  that contains a frame  44 , which in turn supports roller  30 . Frame  44  comprises matching upper and lower plates  46   a  and  46   b  ( FIG. 8 ) with vertically elongate structural members  48 ,  50 ,  52  and  54  interposed between the two plates. Members  52  and  54  define a slot  56  and pocket  40 . Members  48  and  50  enable conventional fasteners  58  to fasten frame  44  within housing  42 . The orientation of frame  44  within housing  42  is based on which side of the doorway support member  26  is to be installed. This feature will be explained later.  
         [0040]     Roller  30  is installed between the upper and lower plates  46   a  and  46   b  with panel  24  extending through slot  56 . The main section of panel  24  is sufficiently thin to slide through slot  56  with the proximal end  36  of panel  24  being inside housing  42  and the distal end  38  of panel  24  being on the other side of slot  56 .  
         [0041]     To urge roller  30  to its stored position, roller  30  is preferably associated with a retracting mechanism, such as a conventional torsion spring  60 , which is schematically depicted by an arrow that indicates the direction that spring  60  urges roller  30 . When panel  24  disconnects from second support member  28 , spring  60  acting upon roller  30  draws panel  28  into first support member  26  for storage.  
         [0042]     Referring to  FIG. 2 , to move barrier  10  to its blocking position, a pliable handle strap  62  on distal end  38  can be used to manually pull rollup panel  24  onto a hook assembly  64  of second support member  28 . Hook assembly  64  includes one or more hooks, such as hooks  66 ,  68  and  70 , which can be welded to a plate  72 , which in turn is bolted to the main section of support member  28 . To couple panel  24  to support member  28 , the distal end  38  of panel  24  includes a metal bar  74  that can be hooked onto hook assembly  64 . When panel  24  is in its stored position, bar  74  can stow within pocket  40  so as not to interfere with nearby traffic. When panel  24  is at its blocking position, bar  74  being vertically elongate helps distribute a force of impact  76  ( FIG. 6 ) more evenly along the vertical span of panel  24 .  
         [0043]     To prevent impact force  76  from pulling panel  24  out from within first support member  26  or damaging roller  30  and its retracting mechanism, panel  24  carries a stop member  78 , such as a pipe, bar, or other structure that is too thick to fit through slot  56 . The structure surrounding slot  56  serves as a catch member  80  that prevents panel  24  from pulling stop member  78  out through slot  56 . Thus, most of a reactive force  82  that opposes impact force  76  passes through panel  24  and first support member  26  and bypasses roller  30  due to the interaction between stop member  78  and catch member  80 . Stop member  78  is preferably vertically elongate to evenly distribute reactive force  82  across the height of panel  24 . It will be appreciated that other reactive forces, including for example reactive force  82 ′, will be present in the system. Reactive force  82 ′ is distributed vertically along the vertical span of panel  24 , and is ultimately taken up by the second support member, by virtue of bar  74  and its interaction with hook assembly  64  in the current embodiment.  
         [0044]     To fit barrier  10  to various width doorways, stop member  78  can be selectively inserted into one of several possible sleeves  84 ,  86  or  88  that are sewn or otherwise attached to panel  24 . In this example, each sleeve comprises three vertically spaced apart loops formed of the same material as the panel&#39;s reinforcing straps. Stop member  78  is inserted in the selected sleeve while that sleeve is on the roller side of slot  56 , thus the chosen sleeve determines how far panel  24  can extend out from within first support member  26 .  
         [0045]     The horizontal spacing between sleeves  84 ,  86  and  88  enables the length of barrier  10  to be adjusted in discrete increments equal to the spacing between adjacent sleeves. Finer length adjustments can be achieved by changing the location of where mounting plate  72  of hook assembly  64  is attached to support member  28 . In selecting a location, second support member  28  includes several series of mounting holes  90  from which to choose. The actual spacing between adjacent sleeves of panel  24 , and the spacing between adjacent vertical rows of holes  90  can vary depending on the design; however, in some embodiments sleeves  84 ,  86  and  88  are spaced at twelve-inch increments, and the rows of holes  90  are horizontally spaced at three-inch increments, so the extended length of panel  24  can be adjusted in three-inch increments over a length of  24  inches.  
         [0046]     Minor reconfiguration of support members  26  and  28  allow interchanging their locations so that either support member can be on the right or left side of a doorway. For doorway  12 , for example, support members  26  and  28  can be reinstalled as shown in  FIG. 8 . To do this, frame  44  is inverted on first support member  26 , and hook assembly  64  is inverted on second support member  28 . Hook assembly  64  can be inverted by using the same mounting holes  90 . To permit the inverted installation of frame  44 , however, housing  42  is provided with two sets of mounting holes  92  and  94  from which to choose. Housing  42  also includes a right-hand opening  96  and a similar left-hand opening  98  through either of which panel  24  can extend depending on the orientation of frame  44  within housing  42 .  
         [0047]     To warn others in the area of dock  16  that a drop-off hazard may exist, even when door  22  is closed, panel  24  may be of contrasting colors (e.g., red and yellow, black and yellow, etc.). In some embodiments, for example, straps  34  are yellow and web  32  is red. Alternatively or in addition to, a warning label  100  can be prominently displayed on panel  24  to suggest that a safety hazard exists.  
         [0048]     Although the invention is described with reference to a preferred embodiment, it should be appreciated by those of ordinary skill in the art that various modifications are well within the scope of the invention. The barrier, for example, could comprise two retractable panels with one panel extending from one support member and the other panel extending the other support member. The two panels could then come together and connect to each other somewhere between the two support members. Each support member could have its own take-up member for its respective panel. Having the spring return force of one take-up member be less than that of the other could soften the impact of something striking the barrier. Storing two smaller panels on two support members rather than storing one large panel on a single support member could reduce the size of the larger of the two support members. Therefore, the scope of the invention is to be determined by reference to the following claims: