The subject disclosure generally pertains to loading dock seals and more specifically to a unique support panel for such a seal.
When an exterior doorway of a building is used as a loading dock for vehicles, such as trucks and tractor/trailers, the perimeter of the doorway often includes a dock seal. Dock seals close off gaps that would otherwise exist between the exterior face of the building and the back end of the trailer. Dock seals allow cargo from the rear of the trailer to be loaded or unloaded while dockworkers and the cargo are protected from the weather. Usually two side seals run vertically along the lateral edges of the doorway, and a top or head seal runs horizontally along the doorway's upper edge; however, additional seals can also be used.
A typical dock seal comprises a resiliently compressible foam core supported by a rigid backer, such as a wood plank or a formed metal plate. The foam core and backer are normally encased within a fabric outer cover. Sealing is provided by backing the trailer up against the seal so that the seal compressively conforms to the rear shape of the trailer. The foam core provides the necessary compliance and resilience to repeatedly conform to the shape of various trailers; the outer cover protects the foam core from dirt, water and wear; and the backer provides solid structure for mounting the seal to the wall and for supporting the foam core so that the foam core does not twist and roll within the fabric cover.
Due to the trailer's wheel suspension, adding or removing cargo and/or driving a forklift on and off the trailer bed can cause the rear of the trailer to repeatedly rise and lower a few inches. Although the incidental movement can be a problem, most dock seals are sufficiently wear resistant to tolerate such movement.
A more serious problem, however, can occur after a tractor backs its trailer up against the dock seal, and the trailer is subsequently unhitched from the tractor while the trailer is still up against the seal. The front end of the unhitched trailer might then be set back down on the trailer's landing gear or temporarily rehitched onto a special tractor (yard jockey or yard mule) designated specifically for shuffling trailers around the loading dock area. Hitching and unhitching the front end of the trailer can cause the entire trailer to tilt about its rear wheels. The resulting seesaw action produces substantial up and down movement at the rear end of the trailer, which can cut and abrade the dock seal.
Moreover, when the front end of the trailer is raised, which tilts the rear end of the trailer downward, the upper rear edge of the trailer can dig deeply into the dock's head seal. When the front end of the trailer is subsequently lowered, the trailer's rear edge can pry the head seal upward.
In some cases, the trailer's rear edge digs into the seal so deeply that the edge catches the seal's backer and pries the head seal off the wall. This particularly tends to happen with relatively thick backers that are made intentionally thick to provide the foam core with ample support. If the backer is too thin, however, or omitted entirely in order to prevent the trailer's rear edge from catching the backer, the foam core may tend to roll and twist within the outer fabric cover. Thus, it can be difficult to design a backer with a thickness that addresses both problems.
In some embodiments, a dock seal comprises a compressible body reinforced by an ultra-thin support panel.
In some embodiments, the thickness of the support panel is less than 2% of the compressible body's thickness.
In some embodiments, the thickness of the support panel is 0.5-1.5% of the compressible body's thickness.
In some embodiments, the support panel is a substantially flat piece rather than a formed sheet metal pan with flanges. As a flat piece, the support panel's material thickness is substantially equal to its panel projection, which maximizes the compressible projection of the dock seal.
In some embodiments, a flexible panel couples a dock seal and its support panel to a wall such that the flexible panel allows the seal and its support panel to move relative to the wall, wherein the movement is in a direction that is generally perpendicular to the seal's length.
In some embodiments, a support panel is embedded within a compressible body so that the support panel can be readily bonded in place.
In some embodiments, a dock seal includes a front compressible body for sealing against a vehicle and a rear compressible body for sealing against a building wall.
In some embodiments, the compressible body of a dock seal comprises a collapsible frame supporting a pliable cover.
In some embodiments, the support panel of a compressible body includes a series of holes that facilitates bonding the panel in place.
In some embodiments, a dock seal includes a front compressible body for sealing against a vehicle, a rear compressible body for sealing against a building wall, and an intermediate compressible body that helps in bonding a support panel and the rear compressible body to the front compressible body.
In some embodiments, the dock seal includes a compressible body and a support panel, wherein the relative densities and relative projections of the body and the panel are within a specific novel range such that the dock seal is particularly tolerant of deep gouging and prying by a vehicle pressing up against the seal.
When vehicle 10 is backed up against dock seal 20, as shown in
It is not unusual for vehicle 10 to press its rear edges 26 and 28 tightly against dock seal 20. If these edges subsequently move up and down due to vehicle 10 being loaded and unloaded of cargo, or the vehicle's trailer tilts due to the front end of the trailer being hitched or unhitched, then the trailers' rear edges 26 and 28 might dig deeply into seal 20. In some cases, the vehicle's upper rear edge 26 might pry head seal 22 upward from its position of
With a yard jockey, a typical operating sequence would be: 1) a yard jockey lifting the front end of the trailer (thus lowering the trailer's rear edge); 2) the yard jockey forcing the trailer's upper rear edge deeply into the dock's head seal (
To prevent damaging seal 20 under such conditions, head seal 22, lateral seals 24, and/or lower seal 32 can be of a construction that tolerates extreme compression, translation, rotation and/or distortion. This can be accomplished by supporting dock seal 20 with something other than a conventional backer; which is usually relatively thick and consumes volume that could otherwise be used for resilient compression and distortion. If a conventional backer of standard thickness were used to support the compressible portion of the seal, there is less room available for compression. In some cases, the support member is fastened to wall 16 with structure that allows some relative movement between seal 20 and wall 16. Although an example will be described with reference to head seal 22, the same seal design may also apply to lateral seals 24 and perhaps lower seal 32.
Referring to
Although the actual design of head seal 22 may vary, in a current example, support panel 44 is sandwiched between compressible bodies 40 and 42. Referring to
Even though it is conceivable and well within the scope of the disclosure to bond or otherwise attach support panel 44 directly to compressible body 40 and omit compressible body 42, such a design does not work quite as well as having support panel 44 interposed between two bondable bodies. If compressible body 40 is not firmly attached to support panel 44 (due to body 42 being omitted, due to the support panel being too pliable, and/or due to panel 44 and body 40 being of different materials that are not readily bonded by a common adhesive), compressible body 40 might move relative to panel 44 and roll within cover 38. With the addition of compressible body 42, it has been found that bodies 40 and 42, being of a similar material, can be readily bonded to each other to firmly capture support panel 44.
In a current example, compressible bodies 40 and 42 are made of a class L24 open-cell polyurethane foam; however, other foams and compressible or collapsible structures are well within the scope of the disclosure. Cover 38 can be any appropriate material including, but not be limited to, HYPALON, canvas duck, rubber impregnated fabric and coated nylon fabric. Support panel 44 can be made of metal, plastic or some other material that is substantially thinner and denser than front compressible body 36.
To mount head seal 22 to wall 16, any suitable fastener 54 can be used to fasten support panel 44 directly to the face of wall 16 or used to fasten support panel 44 to one or more flexible panels 56, which in turn are mounted to wall 16 via another fastener 58. When vehicle 10 pries upward against seal 22, as shown in
To maximize the compressibility of head seal 22, support panel 44 is much thinner than front compressible body 40. When in the relaxed state of
Also, head seal 22 may have a density ratio of less than 3%, wherein the density ratio is defined as density of front compressible body 40 divided by the material density of support panel 44. Even better results are achieved when the density ratio is less than 1%. For an optimum combination of the projection ratio and the density ratio, the density ratio is may be less than the projection ratio. For a current example, compressible projection 64 is about 8 to 23 inches, panel projection 66 is about ⅛ inch, front body 40 has a density of about 1.5 pounds per cubic foot (24 kg/m3), and support panel 44 has a material density of about 480 pounds per cubic foot when made of steel or about 58 pounds per cubic foot when made of HMW polyethylene.
To facilitate manufacturability, a slightly modified head seal 72 can be made as shown in
In other embodiments, shown in
In this particular example, each mechanism 106 includes a generally rectangular frame 108 (or some other suitable shape) with a generally U-shaped brace 110. The actual shapes of frame 108 and brace 110 may vary. Rotatable couplings 112 pivotally connect both legs of brace 110 to intermediate points on frame 108. A central section 114 of brace 110 can pivotally rotate within one or more anchors 116 that are fixed relative to wall 16. Frame 108 includes a section 118 that can both slide and pivot within a slot 120 defined by a track member 122. The pivotal connections at anchors 116 and couplings 112, and the combination pivotal/sliding connection at slot 120 allow frame 108 and brace 110 to move between the positions shown in
To help hold cover 104 taut, an elastic member 124 held in tension pulls an outer edge 126 of each frame 106 towards each other. Examples of elastic member 124 include, but are not limited to, a latex tube, a neoprene cord, helical spring, elastic strap, and the like. Elastic member 124 can be attached to frame 108 in any suitable manner. A similar elastic member 128 can be used for holding cover 104 to support panel 98, while a peripheral lip 130 on cover 104 can provide sealing between wall 16 and dock seal 94.
In some cases, elastic member 124 can be used for urging the dock seal to its expanded position. In other cases, however, where edge 126 moves in a generally linear motion between its positions of
Even though various head seals and lateral seal have been shown as generally straight elongate members, it is well within the scope of the disclosure to provide similarly constructed dock seals of other shapes and designs. Instead of one long member, for instance, head seals 22 and 76 can be comprised of two or more shorter segments that are mounted end-to-end to create an elongate seal assembly of a desired length.
In other cases, as shown in
As an alternative to the embodiment of
Although the invention is described with respect to various examples, modifications thereto will be apparent to those of ordinary skill in the art. The scope of the invention, therefore, is to be determined by reference to the following claims: