The application relates to an overhead door assembly and particularly to a sectional door having elongated panels.
Overhead door assemblies, such as those generally used in loading docks, garages, warehouses, or other enclosed structures, typically include a sectional door assembly that is guided by a vertical track installed on either side of the doorway. Follower elements, such as rollers, are typically affixed to the door assembly and ride within the track as the door is raised and lowered. The door may be raised and stored in a generally vertical orientation, such as found in vertical lift and high lift installations, or the door may travel to a horizontal overhead position, such as found in a standard lift installation. Regardless of configuration, the doors can be manually operated up and down, or motor-driven. To ease the operation of the door, a torsion spring is often used to offset the weight of the door assembly.
According to one aspect, an impact resistant sectional door includes a plurality of interlockingly coupled extruded thermoplastic polymer elongated panels stacked adjacent to one another. An elongated panel edge includes a channel and an adjacent edge of an adjacent panel includes a protrusion. The protrusion nests in the channel. Each end of each elongated panel is supported by an end cap. The impact resistant sectional door also includes a plurality of door hinges. Each end cap is rotatingly coupled to an adjacent end cap by the door hinge having a shaft with a roller slidingly mounted in a pivot between adjacent end caps. The roller is adapted to ride in a door track and to pivot about a rolling plane of the roller. An impact load applied to one or more elongated panels causes one or more of the elongated panels to elastically deform at a spring rate in response to the impact and one or more of the protrusions to slide away from one or more of the channels, while at least one shaft slides in at least one pivot of the plurality of door hinges and at least one roller pivots while remaining in the door track. The impact resistant sectional door remains substantially undamaged.
In one embodiment, two or more elongated panels share a common pair of end caps.
In another embodiment, the elongated panel is about 96 inches long and the impact load causes a deflection at or near a mid-span of about 4 inches.
In yet another embodiment, the elongated panel is about 18 feet long and the impact load causes a deflection at or near a mid-span of about 4 feet.
In yet another embodiment, the protrusion includes a trapezoidal shape and the channel includes a similar trapezoidal shape.
In yet another embodiment, a ledge of a first elongated edge of at least one of the elongated panels is separated from an adjacent ledge of an adjacent elongated panel second elongated edge by a gap VGAP2, and a peak of the protrusion is separated from a trough of the channel by a gap VGAP1 and wherein VGAP2 is less than VGAP1.
In yet another embodiment, at least one elongated edge and an adjacent elongated edge of at least a portion of the elongated panels includes a relief cut near at least one face side of the elongated panel.
In yet another embodiment, at least a portion of adjacent elongated panels both include the relief cut at or near at least one face of the elongated panels and the relief cuts form an angle of about 120 degrees therebetween.
In yet another embodiment, the end caps include U channels.
In yet another embodiment, the thermoplastic includes PVC.
In yet another embodiment, the thermoplastic comprises a flexible material.
In yet another embodiment, the impact resistant sectional door remains substantially undamaged as defined to about plus or minus 20% by the equation: Deflection≈(8−6×fd2)+(0.0034×fd)+0.19, where the Deflection is in inches and fd is the force in pounds applied to the door at about a midpoint of the door.
In yet another embodiment, the impact resistant sectional door remains substantially undamaged as defined to about plus or minus 20% by the equation: Deflection≈(0.005×fd)−0.05, where the Deflection is in inches and fd is the force in pounds applied to the door at about a midpoint of the door.
In yet another embodiment, each of the elongated panels includes hollow cavities and further includes insulation disposed within and one or more of the hollow cavities defined by one or more internal support ribs adapted to substantially maintain a shape of the elongated panel during an expanding insulating foam cure process.
In yet another embodiment, at least one of the elongated panels includes three internal support ribs spanning from a front face of the elongated panel to a rear face of the elongated panel, at least one of the ribs disposed at about a center of the elongated panel.
In yet another embodiment, the impact resistant sectional door further includes an additional hinge between one or more adjacent groups disposed at about mid-span of the elongated panels.
In yet another embodiment, the impact resistant sectional door further includes at least two extruded thermoplastic polymer elongated panels stacked adjacent to one another, the elongated panel edge includes a tube and the adjacent edge of the adjacent panel includes a knob, the knob rotatingly nesting in the tube to form a knob-tube joint, the end caps of the at least two extruded thermoplastic polymer elongated panels further includes a break-away brush coupling to the door track, wherein following a deflecting impact load applied to the elongated panels having the knob-tube joint, the at least two extruded thermoplastic polymer elongated panels push away from the door track while rotating about the knob-tube joint.
According to another aspect, a flexing impact resistant sectional door includes a plurality of interlockingly coupled extruded thermoplastic polymer elongated panels stacked adjacent to one another. An elongated panel edge includes a channel and an adjacent edge of an adjacent panel includes a protrusion. The protrusion nests in the channel. Each end of each elongated panel is supported by an end cap. The flexing impact resistant sectional door also includes a plurality of door hinges. Each end cap is rotatingly coupled to an adjacent end cap by the door hinge having a shaft with a roller slidingly mounted in a pivot between adjacent end caps, the roller adapted to ride in a door track and to pivot about a rolling plane of the roller. An impact load applied to one or more elongated panels causes one or more of the elongated panels to elastically deform at a spring rate in response to the impact and one or more of the protrusions to slide away from one or more of the channels. At least one shaft slides in at least one pivot of the plurality of door hinges and at least one roller pivots while remaining in the door track. In response to the impact load, one or more elongated panels deflect and following removal of the impact load, the flexing impact resistant sectional door assumes an original unflexed intact state.
According to yet another aspect, a flexing impact resistant sectional door includes a plurality of interlockingly coupled extruded thermoplastic polymer elongated panels stacked adjacent to one another. An elongated panel edge includes a channel and an adjacent edge of an adjacent panel includes a protrusion. The protrusion nests in the channel. Each end of each elongated panel is supported by an end cap. The flexing impact resistant sectional door also includes a plurality of door hinges. Each end cap is rotatingly coupled to an adjacent end cap by the door hinge having a shaft with a roller slidingly mounted in a pivot between adjacent end caps. The roller is adapted to ride in a door track and to pivot about a rolling plane of the roller. An impact load applied to one or more elongated panels causes one or more of the elongated panels to elastically deform at a spring rate in response to the impact and one or more of the protrusions to slide away from one or more of the channels, while at least one shaft slides in at least one pivot of the plurality of door hinges and at least one roller pivots while remaining in the door track. In response to the impact load, one or more elongated panels deflect and following removal of the impact load, the sectional door remains in a partially deflected state until pushed back into an original unflexed intact state.
According to yet another aspect, a method for protecting a sectional door from an impacting force includes: providing the sectional door which includes a plurality of extruded thermoplastic polymer elongated panels nestingly coupled to each other by interlocking arrangement between adjacent elongated panels of a protruding cam on an edge of the elongated panel and a recessed cam channel on an edge of another adjacent elongated panel; displacing the sectional door by the impacting force to a face of one or more elongated panels of the sectional door; causing the protruding cam to rise up a surface of the recessed cam channel; removing the impacting force; and restoring the sectional door to an original undamaged state as the protruding cam falls back to an original relationship with respect to the surface of the recessed cam channel.
In one embodiment, the step of causing the protruding cam to rise up includes causing the protruding cam to rise up the surface of the recessed cam channel and to exit the channel and the step of restoring the sectional door to the original undamaged state further includes pushing one or more elongated channels causing the protruding cam to fall back into the channel.
The foregoing and other aspects, features, and advantages of the application will become more apparent from the following description and from the claims.
The features of the application can be better understood with reference to the drawings described below, and the claims. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles described herein. In the drawings, like numerals are used to indicate like parts throughout the various views.
A typical sectional door assembly has a number of elongated panels extending transversely across the width of the door opening. The panels are arranged vertically atop one another and the abutting horizontal edges are pivotally connected by hinges to permit relative rotation between the panels. When the door opens in a standard lift installation, the hinges allow the panels to curve around onto horizontal sections of the guide track. In industrial applications, the panels are typically fabricated from heavy gauge roll formed steel for durability.
One problem with sectional door assemblies, especially in warehouse or loading dock environments, is that they are often hit by forklifts, trailers, loaded pallet jacks, and even trucks. Consequently, the door assembly may sustain damage ranging from moderate to severe. The sectional panels may be permanently deformed, the door assembly may extricate from the track assembly, or the track assembly may buckle to the point of being inoperative. The impact damage may involve expensive repairs, temporary loss of the security and environmental protection provided by the door, and in some cases may require repair of the vehicle that hit the overhead door.
Previous efforts have been made to contend with destructive forces accidentally imparted to sectional doors. In one example, a replacement sectional panel was devised to take the place of the damaged panel. The replacement sectional panel member consisted of several interlocked panel members formed of various widths. The panel members could be assembled in different combinations to create a door panel of a desired total width. In other efforts, various means were used to allow a door to pop out of its tracks to avoid damage
Prior attempts at making an overhead door assembly more tolerant of impact loads generally fall into a broad category termed “knock out” configurations. In one class, the track follower or roller element that is fixed to a door panel is designed to disengage or pop out from the guide track, thereby reducing to zero the resultant forces imparted to the track and/or building wall. In one particular example, the track follower comprises stiff nylon brush bristles secured to the vertical edges of each panel. The bristles, which are positioned horizontally along the vertical edge of each panel, span the entire vertical length of the door assembly and ride inside the guide track. The bristles provide much lower resistance in case of an impact, and safely pop out of the track at smaller impact loads. In another class, the panel may disengage from the roller element. A release mechanism springs the panel free from the track, allowing it to safely pivot out of the way.
Once disengaged, various methods have been devised to reengage the panel or roller elements. Some methods are complex, and some are claimed to be simple, but all require manual effort and involve interruption of work time. Furthermore, once the panels are disengaged from the track there no longer exists an environmental seal around the door, which may be critical in refrigerated operations. Thus, although prior ‘knock-out’ methods can be useful and may be advantageous for certain applications, they suffer drawbacks.
Most overhead door assemblies fall into two general categories. A first category encompasses unmodified doors that are rigid and unyielding, and therefore highly susceptible to impact damage. A second category encompasses so-called knock-out designs that pop out at pre-determined impact loads, but require reinstallation to the track.
It was realized that there is a need for a more flexible door assembly that can yield or deflect under impact load but, like a spring, return to its original position without having to be reinstalled.
One solution is a new flexible overhead door assembly includes elongated panels which have a characteristic spring rate. In some embodiments, the spring rate permits the door assembly to deflect over three inches under an impact load of approximately 400 pounds, and then return to its original position when the impact load is removed. It was further realized that a flexible overhead door assembly having elongated panels that can absorb a large impact load without popping out of the tracks and without damaging the track follower elements can solve the problem of overhead door assembly impact.
The spring rate can be achieved, for example, by arranging the door panels into flexible segments. In one exemplary embodiment, the elongated door panels are interlocked and paired. The interlock along the longitudinal or lateral seam between a pair of panels can be configured to allow relative movement such that when impacted, one panel follows a constrained path. When the impact load is removed, the constraining forces cause the panel to move in reverse direction and return to its normal position.
The sectional door assembly 14 has a number of elongated panels 18 extending transversely across the width of the door opening. In some embodiments, in order to provide the required flexibility and environmental endurance, each panel 18 may be formed of ultraviolet-inhibited, weather resistant polyvinylchloride (PVC). The panels may be arranged vertically atop one another with an interlocking feature. Furthermore, the panels 18 may be grouped to provide a characteristic spring rate for the sectional door assembly 14. In some embodiments, the panels 18 are grouped in pairs 19a, 19b, 19c, and 19d. Note that in the exemplary embodiment of
An end cap 22 may be provided to support the flexible panels 18 on each side. In the exemplary embodiment of
Typically elongated panels are similar to each other, such as when extruded from a common mold. However, there can be embodiments where elongated panels are different from an adjacent elongated panel. For example, there could be an elongated panel with a protrusion running along both edges next to an adjacent elongated panel having corresponding channels running along both edges.
Also, the panels at the two ends of the door (e.g. the top most and bottom most elongated panels) might or might not have channels or protrusions, because those two elongated panels typically do not engage the edge of an adjacent panel.
As noted earlier, the panels 18 may be secured at their ends by a rigid end cap 22. Combinations of materials, as described herein, including, for example, size, gap spacing, a characteristic spring rate allow the door assembly 14 to flex and return to its original shape.
Example: Elongated panels 18 were formed of PVC having a width W=96 inches, a height H=12 inches, and a thickness t=3.0 inches. Suitable vertical and horizontal gaps were found to be in a range between 0.10 and 0.30 inches, which provided some lateral movement prior to contact. Additionally, a relief cut defined by α=120 degrees allowed for further deflection and rolling.
Example: A panel and interlock arrangement sustains a 400 pound impact force, deflects approximately three inches, and returns to its original shape.
Referring now to
It can now be seen that an impact resistant sectional door typically includes a plurality of interlockingly coupled extruded thermoplastic polymer elongated panels stacked adjacent to one another. An elongated panel edge includes a channel and an adjacent edge of an adjacent panel includes a protrusion. The protrusion nests in the channel. Each end of each elongated panel is supported by an end cap. The impact resistant sectional door also includes a plurality of door hinges. Each end cap is rotatingly coupled to an adjacent end cap by the door hinge having a shaft with a roller slidingly mounted in a pivot between adjacent end caps. The roller is adapted to ride in a door track and to pivot about a rolling plane of the roller. An impact load applied to one or more elongated panels causes one or more of the elongated panels to elastically deform at a spring rate in response to the impact and one or more of the protrusions to slide away from one or more of the channels, while at least one shaft slides in at least one pivot of the plurality of door hinges and at least one roller pivots while remaining in the door track. The impact resistant sectional door remains substantially undamaged.
In some situations, in response to an impact load, one or more elongated panels deflect and following removal of the impact load, the flexing impact resistant sectional door assumes an original unflexed intact state, such as without any manual intervention. In other situations, in response to the impact load, one or more elongated panels deflect and following removal of the impact load, the sectional door remains in a partially deflected state until pushed back (e.g. pushed back manually by hands) into an original unflexed intact state.
Method:
It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
This application claims priority to and the benefit of co-pending U.S. provisional patent application Ser. No. 61/878,034, FLEXIBLE OVERHEAD DOOR ASSEMBLY, filed Sep. 15, 2013, and co-pending U.S. provisional patent application Ser. No. 61/879,091, FLEXIBLE OVERHEAD DOOR ASSEMBLY, filed Sep. 17, 2013, both of which applications are incorporated herein by reference in their entirety.
Number | Date | Country | |
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61879091 | Sep 2013 | US | |
61878034 | Sep 2013 | US |