Abstract:
A bumper assembly for a loading dock includes a bumper that is moveable between an operative position and a stored position. In the operative position, the bumper extends well above the dock platform to prevent excessively high trucks, trailer beds, and cargo containers from being parked over the top of the dock platform. In the stored position, the bumper is positioned so as not to obstruct loading and unloading of cargo. In some cases, the bumper is biased to the operative position to encourage operators to normally leave the bumper in that position. In some embodiments, the bumper is selectively moveable away from the vehicle or container that the bumper is blocking to facilitate subsequently moving the bumper to its stored position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention generally pertains to dock bumpers and more specifically to a moveable dock bumper. 
     2. Description of Related Art 
     A loading dock provides a platform of a height roughly equal to that of an average truck trailer bed. This allows forklifts and other pallet carriers to readily transfer cargo between the dock and the trailer bed. Since trailer bed heights vary, the loading dock usually includes a dock leveler that provides an adjustable ramp to accommodate the various heights. When a truck backs into the dock, bumpers mounted adjacent the dock leveler are often used to help prevent the rear of the trailer bed from damaging itself or items associated with the dock, such as a door or door frame. Such bumpers create a gap between the dock and the rear of the trailer bed, thus dock levelers usually include a lip extension that bridges the gap. 
     In some cases, a truck or trailer bed may be excessively high, or a truck may deliver a swap body or similar cargo container to the dock. A swap body is a large container designed to be carried upon the trailer of a truck, or on a ship or railroad car. Swap bodies often have four self-supporting legs that store when in transit, and deploy when left at a loading dock. When delivered to a dock, swap bodies are often too high to catch a conventional dock bumper whose top is generally flush with the dock platform. Thus, the delivery of swap bodies are known to damage docks as well as the swap bodies themselves. The same is true for trucks and trailer beds that are excessively high. 
     A dock-mounted bumper extending several inches above the platform could prevent such damage, but the raised bumper could also obstruct loading and unloading. Although forklifts and pallet carriers themselves are capable of avoiding a raised bumper, the presence of pallets and/or their load on the fork truck may limit this capability, as they may need to be lifted up and over the bumper in order to be placed to either rear side of the trailer bed or swap body. If there is sufficient head clearance within the truck or swap body, a forklift can lift a pallet up and over a raised bumper. However, many pallet carriers can only lift a pallet a couple of inches off the floor, thus the rear sides of the trailer bed or swap body can become virtually inaccessible. 
     Some raised bumpers are moveable, such as those disclosed in French Patent 2686913 and German Patent 29804117; however, they have their drawbacks. Although the &#39;913 bumper raises and lowers, its support frame remains extended above the dock platform, thus the bumper&#39;s frame remains an obstruction. The &#39;117 reference discloses a raised bumper that can slide off to one side. However, once a swap body is leaning tightly up against the bumper, it may be difficult to overcome the friction between the swap body and the face of the bumper, thus making it difficult to reposition the bumper. The same problem could occur if a truck backs its trailer bed tightly up against the bumper. 
     SUMMARY OF THE INVENTION 
     To accommodate truck trailers and swap bodies of various height, a loading dock is provided with a bumper that is moveable between an operative position and a stored position, wherein upon moving from the operative position to the stored position, the bumper moves in a direction that traverses an abutment face of the bumper. 
     In some embodiments, the bumper lowers upon moving from its operative position to its stored position. 
     In some embodiments, the bumper is able to swing away from a truck, trailer, or container that may be parked up against the bumper. 
     In some embodiments, the bumper swings about a substantially horizontal axis. 
     In some embodiments, the bumper swings about an axis that traverses a horizontal plane. 
     In some embodiments, the bumper can rise above a frame that supports the bumper. 
     In some embodiments, the bumper is mechanically urged toward its operative position. 
     In some embodiments, the movement of the bumper is foot-actuated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a perspective view of one embodiment of a moveable bumper in a stored position. 
     FIG. 1B is a cross-sectional view taken along line  1 B— 1 B of FIG.  1 A. 
     FIG. 1C is a cross-sectional view taken along line  1 C— 1 C of FIG.  1 B. 
     FIG. 2A is a perspective view of the moveable bumper of FIG. 1A, but shown in its operative position. 
     FIG. 2B is a cross-sectional view taken along line  2 B— 2 B of FIG.  2 A. 
     FIG. 3A is a perspective view of the moveable bumper of FIG. 2A, but with the bumper released of its operative position and in a retracted position. 
     FIG. 3B is a cross-sectional view taken along line  3 B— 3 B of FIG.  3 A. 
     FIG. 4A is a top view of another embodiment of a moveable bumper in an operative position. 
     FIG. 4B is a cross-sectional view taken along line  4 B— 4 B of FIG.  4 A. 
     FIG. 4C is a partial cross-sectional end view taken along line  4 C— 4 C of FIG.  4 A. 
     FIG. 5A is a top view of the embodiment of FIG. 4A, but with the bumper in a stored position. 
     FIG. 5B is a cross-sectional view taken along line  5 B— 5 B of FIG.  5 A. 
     FIG. 5C is a cross-sectional view taken along line  5 C— 5 C of FIG.  5 A. 
     FIG. 6A is a top view of another embodiment of a moveable bumper in an operative position. 
     FIG. 6B is a front view of the bumper of FIG.  6 A. 
     FIG. 6C is a cross-sectional view taken along line  6 C— 6 C of FIG.  6 A. 
     FIG. 7A is a top view of the bumper of FIG. 6A, but with the bumper shown in its stored position. 
     FIG. 7B is a front view of the bumper of FIG.  7 A. 
     FIG. 7C is a cross-sectional view taken along line  7 C— 7 C of FIG.  7 A. 
     FIG. 8 is the same view as FIGS. 6B and 7B, but with the bumper shown in its retracted, equilibrium position. 
     FIG. 9 is similar to FIG. 1B, but of another embodiment. 
     FIG. 10 is similar to FIG. 2B, but of another embodiment. 
     FIG. 11 is a cross-sectional view taken along line  11 — 11  of FIG.  10 . 
     FIG. 12 is the same as FIG. 10, but with the bumper released. 
     FIG. 13 is similar to FIG. 3B, but of another embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     To accommodate a cargo carrier  21 , such as trucks, trailers and swap body containers of various heights, a loading dock platform  10  is provided with a bumper assembly  12  having a moveable bumper  14 , as shown in FIGS. 1A and 1B through  3 A and  3 B. In this embodiment, bumper assembly  12  includes a bumper frame  16  (a generally U-shaped channel) that is anchored to dock  10 , preferably between a dock leveler  18  and a conventional bumper  20 , although bumper assembly  12  can be used without conventional bumper  20 . Even so, here the conventional bumper  20  helps prevent trucks and trailers of low or standard height from backing up against the building or getting so close as to obstruct the operation of dock leveler  18 ; while bumper  14 , being moveable relative to frame  16 , is able to rise above platform  10  to help prevent higher vehicles and swap body containers from backing up and over dock platform  10 . FIGS. 1A and 1B show bumper  14  in its lowered, stored position, while FIGS. 2A and 2B show bumper  14  in its raised, operative position. 
     To guide the vertical movement of bumper  14  relative to frame  16 , a pin  22  extending from a mounting surface  24  of bumper  14  slides within a slot  26  in frame  16 . A smaller second pin  28  extending from bumper  14  also moves within the constraint of slot  26  to limit the extent to which bumper  14  may swing outward from frame  16 . In some embodiments, pin  28  limits the outward movement of bumper  14  to about one or two inches, as indicated by dimension  30 . If desired, pin  28  may serve as a replaceable weak link should bumper  14  ever be forced outward beyond its normal limit. 
     In some embodiments, bumper  14  is urged to its operative position by a force  32  that is provided by at least one of a mechanical spring force, a gas spring force, gravity, hydraulic actuation, pneumatic actuation, and electromotive actuation. For example, in one embodiment, force  32  is provided by an actuator  34 , such as a normally retracted gas spring  36  that connects pin  22  of bumper  14  to a stationary point  38  on plate  40  of bumper frame  16  (see FIG.  1 C). Actuator  34  is schematically illustrated to represent any type of powered actuator such as those employing hydraulic, pneumatic, or electromotive actuation, and to further represent any type of non-powered spring. 
     To hold bumper  14  at its stored position against the urging of force  32 , a latching mechanism is employed, specifically latch  42  engages pin  22 . Pivoting latch  42  counterclockwise about a pin  44  releases pin  22 , which allows actuator  34  to lift bumper  14  to its raised, operative position. The actuation of latch  42  can be carried out by numerous devices including, but not limited to, a solenoid, a pneumatic or hydraulic cylinder, or a linkage mechanically coupling the operation of the bumper to that of dock leveler  18  or the movement of a vehicle at dock  10 . However, in one embodiment, a foot-actuated release mechanism  46  operates latch  42 . Release mechanism  46  includes a bar  48  having slots  50  that slidingly engage pins or bolts  52  and  54  that protrude from frame  16 . Pushing down on a foot-receiving member  56  extending from the top of bar  48  moves a lower end  58  of bar  48  to release latch  42 . A tension spring  60  connecting pin  54  to a pin  62  urges bar  48  upward and latch  42  counterclockwise. It should be noted that although in some embodiments mechanism  46  and member  56  are foot-actuated, actuation can also accomplished by a variety of other actions including, but not limited to, an overhead door descending to a closed position. Using a door for actuation could automatically raise a bumper as the door closes. 
     As actuator  34  lifts bumper  14 , an angled protrusion  64  on mounting surface  24  engages an angled block  66  that is pivotally connected to frame  16  by way of a pin  68 . Protrusion  64  engaging block  66  forces bumper  14  outward. The upper movement of bumper  14  can be limited by any one of a variety of travel limiting devices, such as the travel limit of actuator  34  itself or a cross bar  70  on mounting surface  24  engaging a stop  72  that is disposed on frame  16 . 
     From the raised, operative position of FIGS. 2A and 2B, bumper  14  can be returned to its stored position by a powered actuator  34  or by the application of a manual force, such as by pushing down against a foot-receiving member  74  on bumper  14 . However, if a vehicle or swap body is parked tightly up against an abutment face  76  of bumper  14 , the resulting pressure against bumper face  76  may make it very difficult to move bumper  14  from its position of FIGS. 2A and 2B directly to its stored position of FIGS. 1A and 1B. Thus, bumper  14  may first need to be moved to a retracted position away from the parked vehicle or swap body. 
     To do this, bumper  14  is moved in a direction that traverses bumper face  76  (in this case, in a rearward direction relative to the vehicle) by first pivoting block  66  downward, away from protrusion  64 , as shown in FIGS. 3A and 3B. If desired, a manually held pipe  78  (FIG. 2B) temporarily engaging a short lever  80  on block  66  can help provide the necessary leverage to manually rotate block  66 . With bar  66  pivoted downward and disengaged from protrusion  64 , bumper  14  is now free to move back and away from the vehicle or container that may be parked at dock  10 . Once the pressure on the abutment face  76  is released, bumper  14  is readily pushed back down to its stored position by applying downward pressure against foot-receiving member  74 . A tapered portion  81  of latch  42  allows pin  22  to snap underneath latch  42 , which holds bumper  14  in its stored position after pressure on foot-receiving member  74  is released. A tension spring  82  urges block  66  to its position shown in FIG.  1 B. 
     A release mechanism is thus provided which, in this embodiment, comprises a block  66  and protrusion  64 . In a first, non-release configuration (FIG.  2 B), the release mechanism prevents the bumper  14  from moving in a direction that traverses the bumper face  76  (i.e. in a rearward direction relative to the vehicle). In the non-release configuration, the release mechanism may also provide a load path for reacting the force applied by the vehicle to the bumper back into a fixed structure such as the loading dock. The release mechanism also has a second, release configuration (FIG. 3B) in which it permits movement of the bumper  14  in a rearward direction—so that the retracted bumper can be returned to a stored position. In this embodiment, the release mechanism is configurable between its first, support configuration and its second, release configuration by virtue of rotation of block  66  about pin  68 . This rotation is facilitated by use of lever  80  acting on block  66 . 
     In operation, bumper  14  is normally left in its raised, operative position of FIGS. 2A and 2B. After a vehicle or container is parked against bumper  14  or  20 , the release mechanism can be placed in its release configuration by block  66  being rotated to release the pressure against bumper  14  and allow bumper  14  to be pushed back down to its stored position of FIGS. 1A and 1B. Since the remaining presence of a bumper above the loading dock surface would otherwise be an impediment to the loading process, the ability of the present bumper to be released and return to a stored position (even when pressure is being applied to the bumper face) is a valuable feature of this design, and (in part) distinguishes this design over those non existing. The vehicle or container is then loaded or unloaded as needed. After the vehicle departs or the container is removed, an operator steps on foot-receiving member  56  to allow bumper  14  to return to its raised, operative position of FIGS. 2A and 2B. 
     In an alternate embodiment, a bumper assembly  84  includes a bumper  86  that provides movement transverse to the bumper face by manually rotating between an operative position of FIGS. 4A-4C and a stored position of FIGS. 5A-5B, that is by rotation about an axis that is generally vertical (more vertical than horizontal). The rotation is provided by a pin  88  that extends downward from a base structure  90  and slips into a sleeve  92  that is embedded in dock  10  at a slight angle. The angle urges bumper  86  to swing towards its operative position of FIGS. 4A-4C. In moving to the operative position, a lip  94  extending from base  90  slips underneath a mating lip  96  that is fixed relative to dock  10 . A latch  98  pivots about a pin  100  in base  90  to catch a forward surface  102  of lip  96 . Lip  96  engaging latch  98  and lip  94  holds bumper  14  in its operative position. 
     Depressing a foot-receiving lever  104  that extends from latch  98  raises latch  98  against its own weight to disengage from surface  102 . This allows bumper  86  to be manually rotated to its stored position of FIGS. 5A-5B. Thus, the release mechanism according to this embodiment comprises lever  104  and lip  96 /surface  102 . In the first, non-release configuration of FIG. 4B, the mechanism prevents bumper  86  from moving transversely to the bumper face. In the second, release configuration disengagement of lever  104  from surface  102  permits the transverse movement. Bumper  86  can be held in its stored position by virtue of the bumper&#39;s rotation simply being at its top-dead-center, or if desired, an obvious detent, stop, or latch can be provided at this position. 
     The use of bumper assembly  84  at its stored and operative positions is similar to that of bumper assembly  12 . 
     In another embodiment, a bumper assembly  106  includes a bumper  108  that provides movement transverse to the bumper face by manually rotating between an operative position of FIGS. 6A-6C and a stored position of FIGS. 7A-7C, that is, by movement of the bumper face between a generally vertical operative position and a generally horizontal stored position. A bumper mounting structure  110  includes two arms  112  that are rotatably pinned to a fixed bumper frame  114  via a pin  116 . A brace  118  is pivotally connected to structure  110  by way of a pin  120 . A lower end  122  of brace  118  rests atop a fixed L-shaped support plate  124  and engages a pivoting plate  126  (see FIG. 6C) to help hold bumper  108  in its raised operative position against the downward urging of a tension spring  128  and/or the pressure a vehicle or container pushing against an abutment face  130  of bumper  108 . 
     Brace  118 , however, can also tuck underneath structure  110  when bumper  108  is in its stored position. Upon bumper  108  moving to the stored position, plate  126  pivots about a fixed pin  130  to cause a latch  132  to engage a lip  134  on structure  110  (see FIG.  7 C). Latch  132  engaging lip  134  holds bumper  108  in its stored position against the upward urging of spring  128 . 
     Spring  128  is connected at points  136  and  138 , which are positioned to provide bumper  108  with an equilibrium position, as shown in FIG.  8 . Such an intermediate position prevents bumper  108  from slamming to either of its operative or stored positions. Thus, bumper  108  is manually moved from its intermediate position to its operative and stored positions by pushing up or down against an upper portion of bumper  108 . In this embodiment, the upper portion of bumper  108  serves as a foot-receiving member  140 . 
     To release bumper  108  from its operative position to its intermediate position, or to release bumper  108  from its stored position to its intermediate position, an operator depresses a foot-receiving member  142  that extends from plate  126 . Depressing member  142  when bumper  108  is in its operative position (FIG. 6C) rotates plate  126  about pin  130  to lower an upper edge  144  of plate  126  below support plate  124 . This allows lower end  122  of brace  118  to slide from support plate  124  and over onto dock platform  10 , thus allowing spring  128  to pull bumper  108  down to its intermediate position. The release mechanism here thus includes plate  126  and brace  118 . In the non-release configuration, engagement between brace  118  and plate  126  in the FIG. 6C position prevents transverse movement of the bumper  108 . In the release configuration, plate  126  no longer forms an impediment to rearward movement of brace  118 , and bumper  108  is thus permitted to also move rearwardly (i.e. in a direction transverse to the bumper face). Depressing member  142  when bumper  108  is in its stored position (FIG. 7C) rotates plate  126  about pin  130  to disengage latch  132  from lip  134 . This allows spring  128  to pull bumper  108  up to its intermediate position. A tension spring  146  having one end  148  fixed and an opposite end  150  connected to plate  126  urges foot-receiving member  142  to a normally raised position. It should be noted that the material thickness of bumper  108  in its stored position may have an objectionable projection above dock platform  10 . In that case platform  10  can be provided with a recess or depression (not shown) to allow bumper  108  to store with its upper surface in a flush relationship with dock surface  10 . 
     FIGS. 9-12 illustrates a bumper assembly  152  that is similar to bumper assembly  12 , but is provided with different actuation and latch/release mechanisms. FIG.  9 . shows assembly  152  with a bumper  14 ′ latched in a stored position; FIG. 10 and 11 illustrate a raised, operative position; FIG. 12 shows bumper  14 ′ being released from its operative position; and FIG. 13 illustrates a retracted position. 
     To raise bumper  14 ′ from its stored position of FIG. 9 to its raised position of FIG. 10, an actuator  34 ′ such as a normally extended gas spring  36 ′ is used. Gas spring  36 ′ has one pin connection  156  on a lug  158  that is fixed relative to bumper  14 ′ and has another pin connection  160  that is fixed relative to a frame  16 ′. Gas spring  36 ′ urges pins  156  and  160  apart, thus urging bumper  14 ′ upward. 
     To hold bumper  14 ′ down at its stored position, against the urging of spring  36 ′, a latch mechanism  162  is disposed near the upper end of bumper assembly  152 . Latch mechanism  162  includes a catch  164  that is attached to a top plate  166  of bumper  154  and releasably engages a lever-actuated hook  168  that pivots about a pin  170 . A tension spring  172  urges hook  168  to engage catch  164 . 
     To release bumper  14 ′ from its stored position of FIG.  9  and allow spring  36 ′ to push bumper  14 ′ up to its operative position of FIG. 10, lever-actuated hook  168  is pushed down, as indicated by arrow  174 , which disengages latch mechanism  162 . In this embodiment, pin  22  reaching the top of slot  26  limits the upward travel of bumper  14 ′, thus eliminating the need for stops  70  and  72  of bumper assembly  12 . It should be noted, that instead of pin  28  of bumper assembly  12 , the outward pivotal motion of bumper  14 ′ can be limited by a U-shaped bar  176  attached to frame  16 ′ and a heal plate  178  attached to bumper  14 ′. The pivoting of bumper  14 ′ can then be limited by bar  176  engaging bumper  14 ′ or by heal plate  178  engaging frame  16 ′. It should also be noted that limiting a bumper&#39;s outward pivotal motion or upward travel in the manners just described could be applied to either bumper assembly  12  or  152 . 
     Disengaging latch  162  also allows a spring-loaded hinge  180  to pivot upper plate  166  upward relative to bumper  14 ′. The upward pivotal motion of plate  166 , in turn, lifts a push arm  182  that can later be used to help release bumper  14 ′ from its operative position. For example, when truck  21  is exerting pressure against an abutment face  76  of bumper  14 ′, the pressure tends to hold bumper  14 ′ at its raised, operative position, thus making it difficult to move bumper  14 ′ directly from its operative position to its stored position. To relieve the pressure, bumper  14 ′ can be moved away from truck  21  in a direction that traverses abutment face  76  by first pushing down on top plate  166 , as indicated by arrow  184  of FIG.  12 . This pivots plate  166  about hinge  180 , which pushes arm  182  downward. This, in turn, forces a butt  186  at a lower end of arm  182  to push down against block  66 , thus pivoting block  66  counterclockwise, as viewed in FIG.  12 . When the distal end of block  66  pivots below angled protrusion  64 ; bumper  14 ′ is free to pivot about pin  22  from the bumper&#39;s operative position of FIG. 12 to its retracted position of FIG.  13 . Upon doing so, angled protrusion  64  rides over the top of block  66 , which pivots block  66  further downward and out of the way. Thus the release mechanism here comprises the same block  66  and protrusion  64  as in the similar embodiment of FIGS. 1-3. Movement of the block  66  to configure the release mechanism in the release configuration is facilitated by the operation of plate  166  and arm  182 . 
     Once bumper  14 ′ backs away from truck  21 , bumper  14 ′ can be readily pushed down from its retracted position of FIG. 13 back to its stored position of FIG.  9 . This can be done manually by pushing down on top plate  166 , or can be done automatically by an overhead door pushing down on plate  166  as the door descends to a closed position. 
     The actual design of push arm  182  can vary, however, in a preferred embodiment the upper portion of arm  182  is guided by a U-shaped guide  188  that is narrow enough to slip between a slot  190  in block  66 , as shown in FIG.  11 . The width of butt  186  can slip between the two angled protrusions  64 , but is too wide for slot  190  of block  66 . This allows butt  186  to recede between protrusions  64  as bumper  14 ′ ascends from its stored to operative position. As bumper  14 ′ ascends, an upper beveled portion  192  of butt  186  rides along a lower tapered portion  194  of block  66 , which pushes butt  186  between protrusions  64 . Butt  186  is preferably biased toward block  66  to ensure that butt  186  upon descending can engage the top of block  66  for releasing bumper  14 ′ from its operative position. Such biasing can be readily accomplished by spring force or by gravity in conjunction with the shape and pivot location (e.g., point  196 ) of arm  182 . 
     Although the invention is described with reference to a preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the claims that follow.