Patent Application
20090235589
The subject disclosure relates generally to a horizontal side-moving door and more specifically to a breakaway element for such a door.
Typical horizontal side-moving doors include either a rigid or semi-rigid planar door panel that translates horizontally in front of a doorway or a flexible door panel that coils about a roller as a leading edge of the flexible panel translates horizontally in front of the doorway. Horizontal side-moving doors with a flexible panel and a roller can be referred to as horizontal side-rolling doors.
Horizontal side-rolling doors, such as the one disclosed in U.S. Pat. No. 4,096,902; include one or two vertical rollers at either one or both lateral edges of the doorway. Some horizontal side-rolling doors have a single roller at one side of the doorway with a single curtain that extends and retracts across the full width of the doorway.
In some cases, the “single curtain” is actually comprised of two layers, each having its own vertical take-up roller. In such cases, the two rollers are right next to each other at one lateral edge of the doorway. As the door opens, the two layers of the curtain separate at the edge of the doorway and wrap upon their respective rollers.
Other horizontal side-rolling doors include two individual curtains, each supported by its own roller at opposite lateral edges of the doorway. For such doors, the leading edges of the two separate curtains meet at the center of the doorway as the door closes. To open the door, the two curtains move apart from each other and wrap upon their own roller (or set of rollers if each curtain has two layers).
The leading edges of roll-up curtains and planar door panels are often reinforced by a relatively rigid vertically elongate member that can be susceptible to being accidentally struck by a forklift passing through the doorway. The collision can damage the door, particularly the elongate member. To prevent such damage, some horizontal side-moving doors have an adjustable telescopic, spring-return arm mechanism with an internal detent or stop that helps establish a normal operating length. The arm mechanism extends diagonally between the elongate member and its supporting track follower. In the event of a collision, the arm mechanism yields resiliently to protect the door. Although somewhat effective, such a mechanism is bulky, heavy and expensive.
Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity and/or conciseness. Additionally, several examples have been described throughout this specification. Any features from any example may be included with, a replacement for, or otherwise combined with other features from other examples.
In order to open and close door 10, the leading edges of curtains 12 and 16 are attached to relatively rigid elongate members 24 that are coupled to a drive unit 26. Members 24 can be made of rectangular steel tubing or any other suitable material and having any suitable shape. For the illustrated example, drive unit 26 comprises two track followers 28 and 30 that are mounted for horizontal translation along an overhead track 32 that is installed in proximity with an upper edge 34 of doorway 14. Elongate member 24 extends downward from track follower 30, and the other elongate member 24 extends downward from track follower 28. A chain 36 and/or cogged belt powered by a motor-driven wheel 38 and an idler wheel 40 is coupled to track followers 28 and 30. Track follower 28 connects to an upper section 36a of chain 36, and track follower 30 connects to a lower section 36b of chain 36 so that depending on the rotational direction of driven wheel 38, drive unit 26 either moves elongate members 24 apart or together to respectively open or close the door 10.
To hold elongate members 24 substantially vertical to facilitate operation and proper-closed alignment of members 24 yet still make the door 10 able to survive an accidental impact with a forklift or some other collision, elongate members 24 are each supported by a brace 40 that includes a readily replaceable, inexpensive breakable member 42, as shown in
In the operative position of
If force 44 or 46 is excessive, breakable member 42 shears or breaks from being in an intact shape (
Upon breakage, to prevent any broken pieces of member 42 from falling to the floor or striking someone or something, a setscrew 60 screwed into lower end 54 and holds a central section 42a (first piece) of breakable member 42 to end 54, and other setscrews 62 screwed into lugs 56 hold broken end pieces (second piece) 42b to lugs 56.
After a breakaway incident, setscrews 60 and 62 can be partially unscrewed, and the broken pieces of member 42 can be replaced by an unbroken member 42 of intact shape. Until such a repair can be done, a pivotal coupling 64 between elongate member 24 and track follower 30 allows member 24 to hang generally vertical so that door 10 can still be open and closed while brace 40 is disconnected.
Pivotal coupling 64 can be a sleeve 66 journalled to a generally horizontal shaft 68, wherein shaft 68 is attached to track follower 30, and sleeve 66 is attached to the upper end of elongate member 24. Such a coupling permits pivotal motion in the same general direction that forklifts pass through doorway 14, thus elongate member 24 can “break away” or swing in a direction that member 24 is mostly likely to be struck.
To ensure that the leading edges of curtains 12 and 16 can come together in sealingly tight engagement when door 10 closes, elongate members 24 preferably hang generally parallel and vertical as viewed face-on in
To ensure that the leading edges of curtains 12 and 16 are substantially coplanar, the length of brace 40 can be made adjustable. In a preferred example, a threaded shank 74 of brace 40 can be screwed farther in or out of ends 50 and/or 54 to adjust the brace's 40 overall length.
In an alternate example, shown in
It should be noted that the actual structure of track 32 and track followers 28 and 30 could vary widely and still be within the scope of the disclosure. In the illustrated example, track follower 30 includes several rollers 76 for weight support and for limiting the tipping of track follower 30. An extension arm 78 can enhance the track follower's 30 ability to resist tipping. Additional rollers 80 can further resist tipping and help guide the track follower 30 along the length of track 32. In some cases, extension arm 78 on track follower 30 and a similar extension arm 82 on track follower 28 can pass by each other in an overlapping relationship, as shown in
At least some of the aforementioned examples include one or more features and/or benefits including, but not limited to, the following:
In some examples, a horizontal side-moving door includes a breakaway feature that protects the door from permanent damage in the event of a collision with the door.
In some examples, the breakaway feature is incorporated in a brace that is used for holding a leading edge of the door's curtain substantially vertical.
In some examples, the horizontal side-moving door is still functional even after a breakaway incident occurs.
In some examples, the breakaway feature includes a shear pin that does not fall to the floor after it shears into multiple pieces.
In some examples, a breakable member is incorporated in a brace that is used for holding a leading edge of the door's curtain substantially vertical. Other than the breakable member breaking, the brace basically has no moving parts once the brace is installed.
In some examples, after the breakable member breaks, a pivotal connection between a track follower and a reinforced leading edge of the door's curtain allows the relatively rigid leading edge to swing away from the general direction of impact.
The foregoing examples provide a better way of protecting a horizontal side moving door from impact. Furthermore, although certain example methods, apparatus and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.
