US20060272222A1

US20060272222A1 - Heat shielded sealing curtain

Info

Publication number: US20060272222A1
Application number: US11/485,878
Authority: US
Inventors: David Hoffmann; Charles Ashelin
Original assignee: Individual
Current assignee: Rite Hite Holding Corp
Priority date: 2000-04-13
Filing date: 2006-07-13
Publication date: 2006-12-07
Also published as: WO2004074140A2; US20030177720A1; WO2004074140A3; US20080047211A1

Abstract

A sealing curtain for a loading dock includes a pliable heat shield that helps protect the sealing curtain from concentrated heat generated by a truck's taillight being pressed against the sealing curtain. The heat shield is preferably placed just underneath a sealing surface of the sealing curtain. The heat shield reflects heat away from an inner surface and disperses the heat over a broader area to reduce the peak temperature of any hot spots. The sealing curtain may be height adjustable to position the heat shield at various heights along the loading dock.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 10/369,973 entitled “Heat Shielded Sealing Curtain,” filed Feb. 20, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 09/548,876, filed Apr. 13, 2000, both of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The subject invention generally pertains to a loading dock and more specifically to a dock seal disposed around a doorway of the dock.
2. Description of Related Art
When an exterior doorway of a building is used as a loading dock for vehicles, especially trucks, the perimeter of the doorway may include a loading dock shelter. The shelter may be formed of rigid or compressible header and side panels. Head curtains and side curtains, referred to collectively as sealing curtains, are typically used over these panels to seal-off gaps that would otherwise exist between the exterior face of the building and the back end of the truck. Such sealing allows cargo from the rear of the truck to be loaded and unloaded while the dockworkers and the cargo are protected from the weather. The header panel runs horizontally across the top of the doorway and the side panels run vertically along each lateral edge of the doorway. Sealing is provided by backing the truck up against the shelter, so that the curtains sealingly engage the vehicle as it is backed-up.
Constant usage damages the external surfaces of dock shelters and these sealing curtains. The curtains, for example, are exposed to harsh weather conditions, made even harsher by fluctuations in weather conditions. Additionally, the curtains are ofttimes exposed to intense heat during normal operation due to the taillights on trucks. This exposure occurs when taillights, located along the upper rear edge of the truck, push against the sealing curtain or dock shelter. The taillight problem is increasingly more prevalent, as the National Highway Traffic Safety Administration (NHTSA) has recently issued interpretative rules/communications regarding Federal Motor Vehicle Safety Standard No. 108. FMVSS-108 requires a cluster of three identification lamps to be mounted as close as practicable to the top of truck vehicles. These lights are ideally placed at the extreme height of the vehicle and are used to identify the vehicle to other motor vehicles.
The lights are often placed in the upper, back corners of truck beds and can create intense heat concentrations that over time will damage dock shelters and sealing curtains, in particular sealing curtains. The lights may be turned off during loading and unloading. But if the truck operator inadvertently leaves the lights on, the outer surfaces of the dock shelter or sealing curtain will absorb the heat generated by these taillights. The excessively high temperatures that result will wear on the structures, degrading their appearance. More importantly, the high temperatures may crack the structures and, in some extreme cases, may even cause the structures to burn or melt at the points of contact.
It is, therefore, desirable to have sealing curtains that can withstand intense heat and still offer other desirable features such as resiliency, lightweight, appearance, etc.

SUMMARY OF THE INVENTION

In order to provide a sealing curtain that can tolerate heat generated by a vehicle's taillight, a sealing curtain comprising a sealing surface for engaging the parked vehicle; and a heat shield adjacent the sealing surface, wherein the heat shield and the sealing surface are pliable and wherein the heat shield has a higher thermal conductivity than the sealing surface to dissipate heat from the parked vehicle across the sealing curtain.
In some embodiments, a heat shield is positioned adjacent a sealing surface to protect the sealing curtain from heat damage.
In some embodiments, a sealing curtain is provided with a heat shield that has appreciable thermal conductivity to help disperse heat.
In some embodiments, a sealing curtain is provided with a heat shield that has appreciable reflectivity to reflect some heat away from an inner surface of the sealing curtain or to reflect some heat away from a material behind the sealing curtain.
In some embodiments, a sealing curtain is provided with a heat shield that can withstand a higher temperature than a sealing surface of the sealing curtain, whereby the heat shield helps protect the sealing curtain from heat damage.
In some embodiments, a sealing curtain is provided with a leading edge that is height adjustable.
In some embodiments, the sealing curtain includes an armor pleat at its edges.
In some embodiments, the sealing curtain includes a head curtain that runs substantially horizontally.
In some embodiments, the sealing curtain includes a side curtain that runs substantially vertically.
In some embodiments, a sealing surface of a sealing curtain includes raised elements that assist in heat dissipation across the sealing curtain.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dock pad that includes a heat shield.
FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1.
FIG. 3 is a cross-sectional view similar to that of FIG. 2, but of another embodiment.
FIG. 4 is a perspective view of an example sealing curtain that includes a heat shield.
FIG. 5 is a perspective view of the sealing curtain of FIG. 4 showing additional detail.
FIG. 6 is a perspective view of an example sealing curtain having an adjustable height.
FIG. 7 is a perspective view of an example structure having a sealing curtain of an adjustable height with two side curtains of separately adjustable height.
FIG. 8 is a perspective view of an example side curtain having a heat shield.
FIG. 9 is a front view of the structure of FIG. 8 showing support struts in the side curtains.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To create a weather seal between the rear of a truck 10 (or some other vehicle) and the perimeter a loading dock doorway 12, a dock pad 14 (or dock pad assembly) is installed, as shown in FIG. 1. In this example, dock pad 14 includes a side pad 16 mounted along each lateral edge of doorway 12, and a top or head pad 18 installed along the doorway's upper edge. Pads 16 and 18 are resiliently compressible, so as truck 10 backs up against them, the pads compressively and sealingly conform to the contour of the truck's rear edges.
To provide dock pad 14 with durability and resilient compressibility, pad 14 includes a resiliently compressible foam core 20 covered by a tough outer cover 22, as shown in FIG. 2. In this example, core 20 consists of a polyurethane or foamed polyester, such as, for example, an L24 open-cell polyurethane foam provided by Leggett & Platt of Carthage, Mo. It should be appreciated by those skilled in the art; however, that a wide variety of other synthetic or natural foams may also work well. In some embodiments, cover 22 is a 3022_MFRLPC_DC7 material provided by the Seaman Corporation of Wooster, Ohio. Other examples of cover materials would include, but are not limited to, HYPALON, canvas duck, rubber-impregnated fabric, and coated nylon fabric.
In assembling pad 14, cover 22 wraps at least partially around core 20, and the two are attached to a relatively rigid backer 24, such a formed steel channel or a wood board. Backer 24, in this example, provides a mounting surface 26 that facilitates the installation of pad 14. A conventional fastener or anchor can be used to attach backer 24 to a wall 28 of a loading dock 30. In some embodiments, cover 22 attaches to the side edges of backer 24 by any one of a variety of fasteners including, but not limited to, screws, VELCRO, rivets, hooks, and adhesive. Core 20 can be frictionally held to cover 22, or the two can be joined in a more positive manner. For example, cover 22 can be connected to core 20 with adhesive, straps, hooks, VELCRO, stitches, screws, etc.
To make pad 14 more resistant to heat, such as heat generated by a taillight 32 pressing against certain points 34 on a sealing surface 36 of pad 14, a heat shield 38 is attached to pad 14. In some embodiments, heat shield 38 is incorporated within a Commercial Material RTCM01, which consists of two flexible sheets or layers of perforated aluminum foil reinforced with a polyethylene scrim or fabric, as provided by Radiant Technology, of Dallas, Tex. The flexibility of shield 38 is preferably sufficient to allow dock pad 14 to compressively conform to the contour of the truck's rear edges and then decompress to the pad's original shape. Heat shield 38 can be attached to pad 14 using adhesive, friction, hooks, straps, stitches, and/or various other fasteners. Shield 38 can be attached to the exterior or interior of pad 14, however; shield 38 is preferably installed between cover 22 and foam core 20 for structural, functional, and aesthetic reasons.
Placing shield 38 underneath cover 22, helps keep cover 22 exposed to the outside, thus taking advantage of the cover's toughness, weather resistance and pliability. Moreover, shield 38 preferably has a higher reflectivity than core 20 and cover 22. This can be beneficial in cases where the cover can withstand a higher temperature than the core, wherein “withstand a higher temperature” means a material can be raised to the higher temperature and then substantially recover its original properties after its temperature returns to normal. For example, if the foam of core 20 has an auto ignition point (i.e., temperature at which the material self-ignites without being triggered by a spark or a flame) of 700 degrees Fahrenheit and cover 22 has an auto ignition point of 900 degrees, then heat shield 38 with high reflectivity could reflect heat away from the foam and redirect it into cover 22, which may be able to handle the heat better. In some embodiments, both cover 22 and core 20 have a lower auto ignition point than heat shield 38 (e.g., when shield 38 is one of the two layers of aluminum foil contained within Commercial Material RTCM01).
To reduce peak temperatures of core 20 and/or cover 22 when heated by taillight 32, heat shield 38 is made of a material that has a higher thermal conductivity than core 20 and/or cover 22. The maximum temperature at areas of concentrated heat, such as points 34, is reduced by shield 38 being able to effectively disperse the heat over a broader area. The term, “thermal conductivity” refers to a material's ability to conduct heat of a given temperature gradient along a given length and through a given cross-sectional area of the material, thus thermal conductivity is a property of the material itself, and is generally independent of the material's shape. A typical unit of measure for thermal conductivity would be (Btu)/(hr)(ft)(° F.).
To provide even greater heat protection, another embodiment, similar to that of FIG. 2, provides a dock pad 14′ with two heat shields 38′, as shown in FIG. 3. It is believed that additional heat protection is provided by the additional overall thickness of the two shields and perhaps partially provided by virtue of an additional slight air interface 40 that may exist between the two shields 38′. Moreover, for a given total thickness, two individual shields instead of one relatively thick one is more flexible, just as a stack of individual cards is more flexible than a stack of cards whose faces are glued together.
A strap 42 inserted through a slit 44 in foam core 20′ helps hold the two shields 38′ in place. A loop 46 at each end of strap 44 engages holes 48 in shields 38′; however, strap 42 could attach to shields 38′ in a variety of other ways as well. Also, strap 42 could feed around the back of core 20′ to eliminate the need for slit 44; however, strap 42 extending through slit 44 helps keep strap 42 and shields 38′ from shifting along the length of a pad.
To provide even greater heat protection, FIGS. 4 and 5 show an embodiment with a sealing curtain 50 (a head curtain, in this illustration) that has an integral heat shield. The sealing curtain 50 is installed around a loading dock doorway 52, partially covering side pads 54. The sealing curtain 50 may be adapted for retrofitting onto existing dock pads, extending over an existing head pad and side panels. The sealing curtain 50 includes two armor pleat sections 56 and 58 at the outer sides of the sealing curtain 50. The armor pleats 56 and 58 are formed of a series of overlapping sections 60 and 62, respectively. The armor pleats 56 and 58 may be positioned to coincide with the edges of the sealing curtain 50. The edges of the truck, where intense lights are disposed, typically contact the sealing curtain 50 at the armor pleats 56 and 58, which provide additional abrasion protection when the truck is backed into and away from the doorway 52. Additional pleats may be employed extending down the length of the side panels 54 to offer further protection. The overlapping sections 60 and 62 reduce abrasion wear not only because of extra layering, but also because sections are movable relative to one another.
In addition to pleats, the side panels 54 may each include heat shield layers, for example, if the side panels 54 are side pads formed of compressible foam cores that are susceptible to heat damage.
The sealing curtain 50 includes a middle section 64 extending between the armor pleats 56 and 58. The middle section 64 is formed of an outer, sealing surface 66 and an inner surface 68, as shown in FIG. 5. Sandwiched between surfaces 66 and 68 is a heat shield 70. The heat shield 70 may be any of the materials described with respect to other examples described herein. The heat shield 70 preferably has a higher heat reflectivity than the sealing surface 66 and the inner surface 68. Therefore, the head shield 70 will not only protect covered structures, like head panels or side panels, it will also protect the sealing curtain 50 itself.
The material of the heat shield 70 may have a higher thermal conductivity than the surfaces 66 and 68, as described above, as well. As a higher thermal conductivity material, the heat shield 70 will disperse heat from the high-temperature points where a taillight abuts the sealing curtain 50. Dispersing heat through a high thermal conducting material will greatly decrease the likelihood that the sealing curtain 50 will be damaged at these hot spots. High thermal conductivity materials, like aluminum-based materials, are preferred, due to their durability, resistance to deformation over time, structural support, and flexibility. As with heat shield 38, the heat shield 70 may be attached to the sealing curtain 50 using adhesive, friction, hooks, straps, stitches, and/or various fasteners. Also, the heat shield 70 may alternatively be attached at the exterior of the surface 66 exposed to an on-coming truck.
Further still, the heat shield 70 may comprise multiple layers or sheets that individually or collectively provide heat shielding. For example, the heat shield 70 may be a heat trapping structure sandwiched between the surfaces 66 and 68. The heat shield 70 preferably extends from armor pleat 56 to armor pleat 58, so as to provide heat shielding against taillights that may contact at any point on the sealing curtain 50. The heat shield 70 may also extend under the armor pleats 56 and 58 to add further protection at these locations. A heat shield may also be integrated into each of the overlapping sections 60 and 62, if so desired, such that each pleat has a separate heat shield layer.
To further shield the sealing curtain 50 from heat damage, the sealing surface 66 may be embossed with a pattern of raised elements 72. The raised elements 72 may be patterned with sufficient spacing between adjacent elements to further dissipate the heat from a taillight over a number of contacts points. A checkerboard pattern is preferred, though various patterns and various raised elements may be used.
FIG. 6 shows an example sealing curtain 50′, which is similar to that of sealing curtain 50 and which is height adjustable so that it may overhang a desired amount from the top edge of the loading dock doorway 52. The sealing curtain 50′ overhangs upper portions of the side panels 54′, as well. To adjust the sealing curtain 50′, a rod 74 is placed at a leading edge 76 of the curtain 50′. The rod 74 may be attached to the leading edge 76 by overlapping a portion of the sealing curtain 50′ onto itself forming a slot for receiving the rod 74. The rod 74 provides rigidity and preferably extra weight to allow the sealing curtain 50′ to be pulled by a series of ropes 78, 80, 82. The ropes 78, 80, and 82 may be part of a single rope or part of a rope pulling mechanism and either way are used to raise and payout the leading edge 76. The rod 70 may be weighted to bias the sealing curtain 50′ to fall upon release of tension in the ropes 78, 80, 82. A counter-balancing weight may be used to bias the sealing curtain 50′ to a certain height above the floor of the doorway 52. In the illustrated example, the ropes 78, 80, and 82 are connected through loops attached to a frame 84 that extends from the doorway 52. The frame 84 includes parallel slats 86 and parallel slats 88 and 90. The frame 84 may be part of a dock shelter, for example a head panel of the same.
Other pulling mechanisms known to persons of ordinary skill in the art may also be used for moving the sealing curtain 50′. For example, it may be useful to use a chain in lieu of ropes, and it may be desirable to use either a manual pull mechanism or an automatic one.
Adjusting the position of the leading edge 76 allows the sealing curtain 50′ to provide heat shielding for vehicles of various heights. Thus, the sealing curtain 50′ provides an adjustable-height heat shield for a loading dock. Preferably, the heat shield is formed of a material that is flexible enough to pay out from a raised position and structurally rigid enough to maintain its shape and properties in a lowered position.
Numerous alternatives to the examples shown may be used, for example, sectioning the sealing curtain 50′ so that a middle portion 64′ or an armor pleat portion 56′ (not shown) 58′ are separately height adjustable. FIG. 7 shows an example heat shielding structure 100 formed of a sealing curtain 101 having a head curtain 102, a first side curtain 104, and a second side curtain 106, each individually height adjustable. The head curtain 102 is adjustable over a central portion of a doorway 108 and, in the illustrated example, extends below a header panel 110 that extends horizontally across the top of the doorway 108 adjacent two vertically extending side panels 112, 114. The head panel 110 and side panes 112, 114 may be rigid or compressible structures. The side curtain 104 extends over the side panel 112, and the side curtain 106 extends over the side panel 114. In the illustrated position, the side curtains 104 and 106 have been extend below the height of the sealing curtain 102. Also, in the illustrated example, the curtains 102, 104 and 106 each have heat shields like the heat shield 70 described above. A heat shield 116, for curtain 104, is shown sandwiched between a sealing surface 118 and an inner surface 120. The heat shield 116 preferably has a higher heat reflectivity than the sealing surface 118 and the inner surface 120. The heat shield 116 may also have a higher thermal conductivity than the surfaces 118 and 120, as well. Further still, the heat shield 116 may comprise multiple layers or sheets that individually or collectively provide heat shielding. The head curtain 102 has a heat shield (not shown) like the heat shield 70 of FIG. 5. Any of the curtains 102, 104, and 106 may have amour pleats or embossed raised portions, as described above with respect to FIG. 5.
FIGS. 8 and 9 show an example of another application of a heat shield. A vehicle shelter 200 includes a head panel 202 and two side panels 204 attached to an exterior wall face defining a doorway 206. Two side pads 208 are attached to side panels 204 for example using a conventional hook and loop attachment device 210 commonly referred to as Velcro fasteners. The loop portion of attachment device 210 may be attached to one of the side curtains 208 or the side panel 204 and the latch portion attached to the other of the side curtains 208 or the side panel 204, wherein the latch and loop portions may latchably engage each other and attach the side curtain 208 to the side panel 204. The side curtain 208 and the side panel 204 may be selectively released by pulling the hook and loop portions apart.
The size, number and location of the attachment devices 210 may be adjusted to provide the proper support for the side curtain 204. It will be appreciated that the side curtain 208 may be releasably connected to the side panel 204 using snap fasteners, zippers or other methods known to those skilled in the art. If desired the side curtain 208 may also be fixedly attached to the side panel 204 using stitching or other methods known to those skilled in the art which would permanently affix the side curtain 208 to the side panel 204.
The side curtains 208 have heat shields 212 similar to heat shields 70 described above. The heat shield 212 is sandwiched between a sealing surface 214 and an inner surface 216 and may be formed of the materials previously described. In particular, the heat shield 212 preferably has a higher heat reflectivity than the sealing surface 214 and the inner surface 216. The material of the heat shield 212 may have a higher thermal conductivity than the surfaces 214 and 216, as well. Further still, the heat shield 212 may comprise multiple layers or sheets that individually or collectively provide heat shielding. The side curtains 208 may include amour pleats, with or without heat shields, as well.
FIG. 9 shows the side curtains 208 with a plurality of substantially resilient stays 218 (shown in phantom) that provide additional rigidity, lateral support and shape to the side curtain 208 and which may be embedded in the side curtain 208 or slidably inserted into pockets provided in the side curtains 208. The stays 218 will resiliently bias the side curtain 208 towards a substantially straight position.
Although the invention is described with reference to a these examples, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. For example, other sealing curtains employing a heat shield may be used. The sealing curtains, both sealing curtains and side curtains may be attached to dock shelters, compressible dock pads, and the like, in ways other than those depicted. Moreover, the curtains may be used alone. The scope of the invention is to be determined by reference to the claims that follow.

Claims

1. A sealing curtain adapted to seal against a vehicle parked against the sealing curtain, comprising:

a sealing surface for engaging the parked vehicle; and

a heat shield adjacent the sealing surface, wherein the heat shield and the sealing surface are pliable and wherein the heat shield has a higher thermal conductivity than the sealing surface to dissipate heat from the parked vehicle across the sealing curtain.