Release mechanism for a sectional door

Information

  • Patent Grant
  • 6615898
  • Patent Number
    6,615,898
  • Date Filed
    Wednesday, May 30, 2001
    23 years ago
  • Date Issued
    Tuesday, September 9, 2003
    21 years ago
Abstract
A release mechanism for protecting a sectional door under impact allows one or more door panels to breakaway from its guide track without damaging the door. The release mechanism includes a snap-in pin that can be selectively repositioned to provide various operating modes. Examples of operating modes include unidirectional release, bi-directional release, and a disabled mode. In some cases, the breakaway threshold is greater in one direction than another. In the disabled mode, the release mechanism is not meant to release. Some embodiments include a door locking mechanism that still allows the release mechanism to operate.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The subject invention generally pertains to sectional doors and more specifically to a release mechanism for such a door.




2. Description of Related Art




A sectional door typically includes a series of panels whose adjacent horizontal edges are each pivotally connected by a row of hinges. As the door opens or closes, the door panels travel along two lateral tracks that in one configuration curve between horizontal and vertical. To close the door, the tracks guide the panels to a vertical position. When the door opens, the hinges allow the panels to curve around onto horizontal sections of the tracks, where the door panels store horizontally overhead. In other configurations, the sectional door maintains a generally vertical, planar configuration and is stored more directly above the doorway. Such doors, regardless of their configuration, can be powered up or down or can be manually operated. To ease the operation of the door, a torsion spring is often used to offset the weight of the door panels. Sectional doors are commonly used as residential garage doors; however, they are also often used in warehouses and other industrial buildings.




When used in high-traffic industrial applications, sectional doors are very susceptible to being struck by large trucks, trailers, forklifts and other vehicles passing through the doorway. There are different reasons why vehicles collide with doors. One of the more common causes is a door's torsion spring becoming weak with age or not being properly preloaded. This can allow a door to droop down into the doorway from a fully open position or not open fully at all. In such cases, an upper edge of a vehicle traveling through the doorway may strike the lower portion of the drooping door, which can damage one or more door panels, as well as damage door-mounting hardware, such as hinges, rollers and track.




Doors are also often installed adjacent to a dock leveler of a loading dock. When the door is closed, such doors can be damaged as material handling equipment stage loads on the dock leveler. For instance, a forklift may accidentally push a load up against the door.




Consequently, some doors are provided with some type of breakaway feature that allows a door to give way to a collision without being damaged. For example, a sectional door described in U.S. Pat. No. 5,727,614 includes a track-following roller that can break away from its mounting bracket in reaction to a collision. After the collision, the roller can be reattached to the bracket. The breakaway device, however, has its limitations. Upon breaking away, the roller can completely separate from the mounting bracket, thus an impact could throw the roller where it may be difficult to find. This is particularly true for a loading dock door that is installed adjacent to a dock leveler. In such cases, the roller may fall into a pit that is underneath a conventional dock leveler or fall into some snow that may be just outside the building. It also appears that the '614 device breaks away at a predetermined force, which cannot be readily adjusted or altered once the door is installed. Depending on the application, it may be desirable to have a door that breaks away in one direction easier than another. For instance, for heavier doors, it may be desirable to have a higher breakaway force in one direction (from outside to inside), so that the door does not break away under its own weight when fully open and stored overhead. It some cases, for example, it may be beneficial to have a door whose breakaway feature only acts in one direction. In windy areas, it may be better to have a door that only breaks away in an outward direction to avoid the door giving way to strong winds.




Another breakaway device, shown in U.S. Pat. No. 6,039,106 does include a means for adjusting the breakaway force. The breakaway force is adjusted by turning a setscrew, which adjusts the pressure that a spring-loaded plunger exerts against a detent of a track-following guide member. Under sufficient breakaway force, the guide member is able to swing its detent out from underneath the force of the plunger; however, the guide member does not completely separate from the plunger. The swinging motion also releases the guide member out from within the track, which releases the door to avoid damage. Although the device has an adjustable breakaway, it appears that the breakaway force is the same in both directions and that the device cannot be readily locked to disable the breakaway feature.




Other examples of breakaway mechanisms are shown in U.S. Pat. Nos. 5,392,836 and 6,053,237. These devices; however, share some of the same limitations of the other breakaway devices that have already been discussed.




SUMMARY OF THE INVENTION




In order to provide a versatile breakaway device for a sectional door, a release mechanism includes a first member for releasably coupling a track-following guide member to a bracket connected to the door. The first member may be able to snap into and out of the guide member to allow the guide member to move between an operative position where the guide member engages the track and a dislodged position where the guide member separates from the track, or the first member may engage or disengage the guide member in other ways.




In some embodiments, the guide member includes a roller.




In some embodiments, the release mechanism releases easier in one direction than another.




In some embodiments, the release mechanism is selectively reconfigureable to a releasable mode and a non-releasable mode.




In some embodiments, the release mechanism is selectively reconfigureable by selectively inserting a pin in different holes.




In some embodiments, the release mechanism includes a releasable pin that is U-shaped.




In some embodiments, the release mechanism is capable of being reset to its operative position without the use of tools.




In some embodiments, the first member and the guide member completely separate from each other upon moving from the operative position to the dislodged position.




In some embodiments, the guide member is pivotal about the retaining member.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a front view of one embodiment of an overhead-storing sectional door in a partially open position, with the door being viewed from inside a building and looking out.





FIG. 2

is a cross-sectional view taken along line


2





2


of FIG.


1


.





FIG. 3

is a front view of one example of a door panel hinge.





FIG. 4

is an end view of the hinge of FIG.


3


.





FIG. 5

is an end view of one embodiment of a release mechanism.





FIG. 6

is a front view of FIG.


5


.





FIG. 7

is a top view of a guide member of the release mechanism shown in FIG.


6


.





FIG. 8

is a cross-sectional view taken along line


8





8


of

FIG. 1

, showing a release mechanism is an operative position.





FIG. 9

is similar to

FIG. 8

, but with the release mechanism in a dislodged position.





FIG. 10

is similar to

FIG. 8

, but with the pins of the release mechanism in a different position.





FIG. 11

is similar to

FIG. 10

, but with the release mechanism in a dislodged position.





FIG. 12

is a top view of a guide member that provides a release mechanism with bi-directional breakaway.





FIG. 13

is a perspective view of a retainer being inserted into a block of a guide member to provide unidirectional breakaway.





FIG. 14

is similar to

FIG. 13

, but with the retainer being inserted into the block so as to disable the breakaway feature.





FIG. 15

is a top view of the block of

FIGS. 13 and 14

with a roller inserted in the block.





FIG. 16

is similar to

FIG. 8

, but of another release mechanism in an operative position.





FIG. 17

is the release mechanism of

FIG. 16

, but with the release mechanism in a dislodged position.





FIG. 18

is a cross-sectional view taken along line


18





18


of FIG.


16


.





FIG. 19

is similar to

FIG. 1

, but with the door closed.





FIG. 20

is a cross-sectional view taken along line


20





20


of

FIG. 19

(with some features pertaining to the rollers and release mechanism omitted for clarity).





FIG. 21

is a cross-sectional view taken along line


21





21


of

FIG. 1

(with some features pertaining to the rollers and release mechanism omitted for clarity).











DESCRIPTION OF THE PREFERRED EMBODIMENT




A sectional door


10


, shown partially open in

FIGS. 1 and 2

, includes a series of door panels


12


,


14


,


16


and


18


that are interconnected along their adjacent horizontal edges by hinges


20


. As door


10


opens or closes relative to a doorway


22


defined by a wall


23


, guide members


24


guide the movement of the panels along two lateral tracks


26


and


28


. In this example, tracks


26


and


28


curve between horizontal and vertical; however, it is well within the scope of the invention to have tracks


26


and


28


run generally linearly or only curve slightly, so that when the door opens, the door panels move above doorway


22


while remaining in a generally vertical or slightly angled orientation. To close door


10


, the vertical sections of tracks


26


and


28


guide the panels to a vertical position across doorway


22


, as indicated by the positions of panels


12


and


14


. When door


10


opens, hinges


20


allow the panels to curve around onto the horizontal sections of tracks


26


and


28


, where the door panels store horizontally overhead, as indicated by the position of panel


18


.




The actual structure of panels


12


,


14


,


16


and


18


can vary from one door to another, vary among panels of the same door, or be the same for each panel of the same door and still remain well within the scope of the invention. A door panel according to this embodiment comprises a foam core


30


protected by a tough outer shell


32


. Shell


32


may comprise a rectangular metal frame that supports two parallel face panels. The metal frame can also serve as a strong base to which door hardware can be mounted, such as hinges


20


and pliable seals


34


. Seals


34


help seal the gap between adjacent door panels. In some cases, hinges


20


comprise a hinge pin


36


that pivotally couples two U-shaped hinge plates


38


and


40


, as shown in

FIGS. 3 and 4

. Hinge plates


38


and


40


can be fastened to the edge of a door panel by way of fasteners


42


. It should be noted; however, that the present invention can be applied to doors with other types of hinges; different types of seals (or no seals); and door panels of various other designs, such as those that are solid or hollow.




The primary focus of the invention is to provide a sectional door with a feature that helps protect a door that may be subjected to excessive forces, such as forces that occur during an impact. Such a feature can be provided by a release mechanism


44


that allows one or more door panels (or even just part of one panel) to move away from its guide tracks in response to a sufficient breakaway force being exerted against the door.




In a preferred embodiment, release mechanism


44


includes a U-shaped bracket


46


that attaches adjacent an edge (preferably to the frame) of a panel (e.g., panel


12


) by way of a fastener


48


, as shown in

FIGS. 5 and 6

. Between two flanges


50


and


52


, bracket


46


supports guide member


24


, which in this case, includes a nylon block


54


that supports a shaft


56


of a roller


58


(or some other type of track-guided element, not limited to only those that roll). In some cases, the axial position of shaft


56


can be limited or restrained by some feature such as a conventional cotter pin, C-clip, E-clip, push nut, sleeve


102


(to be explained further with reference to

FIG. 15

) or in the case of the preferred embodiment, a setscrew


60


that clamps against the side of shaft


56


.




To render mechanism


44


releasable under impact (or some other sufficient force applied in the direction indicated by arrow


62


of FIG.


9


), block


54


is releasably coupled to bracket


46


in a manner that allows guide member


24


to move from an operative position of

FIG. 8

to a dislodged position of FIG.


9


. At the same time, block


54


is also coupled to bracket


46


such that the guide member


24


stays attached to the panel even after moving to the dislodged position. Toward that end for release mechanism


44


, elongated elements, such as pins


64


and


66


couple block


54


to bracket


46


. The term, “pin” refers to any elongated element, examples of which include, but are not limited to, a clevis pin, roll pin, cotter pin, dowel, screw, rivet, nail, threaded rod, etc. Although pins


64


and


66


are used in a preferred embodiment, other elongated elements that do not necessarily resemble a pin are also well within the scope of the invention. Pin


64


extends through two aligned holes in flanges


50


and


52


, with a portion


64


′ (

FIG. 6

) of pin


64


extending through a hole


68


(

FIG. 7

) in block


54


. In this way, guide member


24


is pivotally mounted to the panel. Alternatively, opposite ends of pin


64


can be welded or otherwise attached to flanges


50


and


52


without the use of holes in the flanges of bracket


46


. In a similar manner, pin


66


also extends through two aligned holes in flanges


50


and


52


; however, to provide release mechanism


44


with the ability to break away, a portion


66


′ (

FIG. 6

) of pin


66


is received within a slot


70


in block


54


. In this way, a releasable coupling is created between guide member


24


and panel


12


, wherein pin


66


is a first member adapted for selective engagement with the guide member


24


to form a releasable coupling that allows the guide member to move from the engaged to the dislodged position by virtue of complete separation between guide member


24


and pin


66


in response to a force exerted in direction


62


, which is generally perpendicular to panel


12


. A neck


72


of slot


70


is reduced in width to allow pin


66


to selectively engage (e.g., snap in or out) with block


54


, as block


54


swings about pin


64


between the operative and dislodged positions. Pin


64


thus forms a second member that fastens guide member


24


to panel


12


such that guide member


24


stays with panel


12


even after it has moved to the dislodged position.




Disengagement between pin


64


and slot


70


occurs when an impact force applied against and generally perpendicular to panel


12


, as indicated by arrow


62


, is reacted by a counter force that track


28


exerts against roller


58


in an opposite direction. The counter force being spaced apart from pin


64


produces a clockwise (as viewed in

FIG. 9

) torque on block


54


about pin


64


. The torque forces block


54


to rotate about pin


64


and away from pin


66


(thus separating therefrom) when the force applied along direction


62


is sufficient release pin


66


from slot


70


.




To return release mechanism


44


from its dislodged position to its operative position, panel


12


is moved back to its normal operating position adjacent track


28


, roller


58


is reinserted into track


28


, and pin


66


and block


54


are reconnected. To reconnect pin


66


and


54


, the two can be snapped back together or pin


66


can be lifted or lowered lengthwise back into slot


70


once slot


70


is realigned with the holes that receive pin


66


. The terms, “snap” and “snapped” refer to the engagement or disengagement of two elements, wherein at least one of the elements resiliently deforms as the two elements engage or disengage.




Although pins


64


and


66


are preferably non-frangible, in some cases it may be desirable to make pin


64


(and/or pin


66


) frangible. Pin


64


when frangible could release block


54


from bracket


46


under a predetermined force that is sufficient to break pin


64


but not be so great as to significantly damage other parts of release mechanism


44


. Thus, a frangible pin


64


can serve as a sacrificial piece that is relatively inexpensive and easy to replace after panel


12


is dislodged. To render pin


64


frangible, pin


64


can be made of a relatively weak material or be sized to limit its strength.




To selectively disable the breakaway feature of release mechanism


44


, pin


66


is removed from slot


70


and the corresponding holes of bracket


46


, and reinserted through another set of holes


74


and


76


that are in bracket


46


and block


54


, respectively, as shown in FIG.


10


.




To allow a door panel to move in response to an impact from either direction (i.e., from inside to outside, as indicated by arrow


62


of

FIG. 9

, or from outside to inside, as indicated by an arrow


76


of FIG.


11


), a release mechanism


44


′ can be provided with a modified block


78


, as shown in FIG.


12


. Block


78


is similar to block


54


; however, a slot


80


in block


78


replaces hole


68


of block


54


. Slots


70


and


80


are similar in that they both allow their respective pins


66


and


64


to selectively and engage and release block


78


. Sufficient force acting against a door panel in the direction of arrow


77


can force block


78


to swing about pin


66


and break away from pin


64


, or sufficient force acting in an opposite direction (direction


62


of

FIG. 9

) can force block


78


to swing about pin


64


and break away from pin


66


. Thus, release mechanism


44


′ has two pivot points: pin


64


and


66


. Moreover, pin


64


in this embodiment forms a second member that is adapted for selective engagement with the guide member. Thus, both pins


64


and


66


are capable of pivotally mounting guide member


24


to panel


12


when breakaway or release occurs about the other pin, while at the same time being capable of themselves selectively disengaging from guide member


24


for an appropriately directed breakaway force. To provide one or more guide member


24


with sufficient clearance to swing to the position of

FIG. 11

, door panel


12


and/or the other door panels are provided with a notched out section


79


.




In some cases, pin


64


and slot


80


, and pin


66


and slot


70


may be sized differently to provide release mechanism


44


′ with a breakaway threshold that is greater in one direction than the other. In other cases, the dimensions of pins


64


and


66


and their fit within their respective slots


80


and


70


may be identical and still provide a threshold differential or breakaway threshold that is greater in direction


77


than in direction


62


by virtue of track


28


being closer to pin


66


than to pin


64


, which provides a leverage advantage to a force acting in direction


62


(opposite to direction


77


). To provide an equal breakaway threshold in both directions, the engagement between pin


64


in slot


80


may be made loser than the engagement between pin


66


and slot


70


to compensate for the threshold differential brought on by pins


64


and


66


being at an unequal distance away from track


28


.




Although pins


64


and


66


have been described as individual pins, the two pins can be joined or formed as a unitary U-shaped retainer


82


, as shown in

FIGS. 13-15

. Retainer


82


comprises a pin


84


and a pin


86


that are connected by a cross member


88


. Retainer


82


can be used in conjunction with a block


90


that is similar to blocks


54


and


78


. The distance between a hole


92


and a slot


94


is preferably the same as the distance between a hole


96


and hole


92


, with the layout of slot


94


and holes


92


and


96


corresponding to a matching pattern of three holes in a bracket similar to that of bracket


46


. Inserting retainer


82


in the position of

FIG. 13

(i.e., pin


84


in hole


92


, and pin


86


in slot


94


) provides a release mechanism that operates like release mechanism


44


of FIG.


9


. And inserting retainer


82


in the position of

FIG. 14

(i.e., pin


84


in hole


92


, and pin


86


in hole


96


) disables the breakaway feature to provide an operating mode similar to release mechanism


44


of

FIG. 10. A

hole


98


for a setscrew


100


is positioned so as not to interfere with hole


96


. Sleeve


102


, as shown in

FIG. 15

, extends over the shaft of the guide roller to reinforce the shaft and help establish a certain spacing between the roller and block


90


.




As a further illustration of the inventive release mechanism, an alternative embodiment including release mechanism


44


″ is provided, as shown in

FIGS. 16-18

. Release mechanism


44


″ includes a guide member


24


′ whose shaft


56


′ is pivotally coupled to a door panel


12


′ by way of a pin


104


that that can be connected to panel


12


′ directly or connected indirectly through a bracket


106


. With sufficient force acting in direction


62


, guide member


24


′ pivots about pin


104


to disengage or separate from a releasable bracket


108


, which is attached to panel


12


′ at a position between pivot pin


104


and the portion of guide member


24


′ engaged with the track. In some embodiments, releasable bracket


108


is a snap-action device; however, bracket


108


is schematically illustrated to encompass any device that is adapted for selective engagement (

FIGS. 16 and 18

) and disengagement (

FIG. 17

) with guide member


24


′. Releasable bracket


108


thus forms a first member adapted for selective engagement with the guide member


24


′ in a similar sense to the way that pin


66


of the embodiment of

FIG. 9

is adapted for selective engagement with guide member


24


. That is, the concept of adapted for selective engagement can encompass the situation where the guide member is yieldable relative to a generally rigid first member (as in slot


70


yielding relative to the generally rigid pin


66


in

FIG. 9

) and the situation where the guide member is generally rigid, and it is the first member that yields relative to the guide member (as in releasable bracket


108


yielding relative to generally rigid shaft


56


′ of guide member


24


′ in FIGS.


16


-


18


). In all of the embodiments described so far, then, the guide member is pivotally mounted to the panel, and a first member is provided that is adapted for selective engagement with the guide member to selectively place the guide member in an operative position and a dislodged position, with the first member and guide member being separated in the dislodged position.




To allow door


10


to be held in a closed position without limiting the breakaway ability of a release mechanism, door


10


is provided with a latch mechanism


110


, as shown in

FIGS. 1

,


2


and


19


-


21


. Latch mechanism


110


includes a base


112


whose position is stationary and a traveling bar


114


, which is attached to panel


14


. A pin


116


rotatably couples an arm


118


to base


112


, so arm


118


that can swing over and thus capture traveling bar


114


to inhibit door


10


from opening, as shown in

FIGS. 19 and 20

. Even though arm


118


engaging bar


114


inhibits panel


14


from rising, door panel


14


can still be forcibly dislodged in direction


62


, because panel


14


(as it becomes dislodged) can move bar


114


from the restraint of arm


118


by moving arm


144


in direction


62


.




To release door


10


under normal, non-breakaway conditions, arm


118


can swing away from bar


114


and preferably swing over and onto a stationary bar


120


that extends from base


112


, as shown in

FIGS. 1

,


2


and


21


. To inhibit arm


118


from accidentally swinging off bars


114


or


120


, a distal end of each bar


114


and


120


can be provided with a hole to receive the shackle of a padlock


122


, whereby padlock


122


can hold arm


118


at either selected location: on bar


114


or


120


.




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.



Claims
  • 1. A release mechanism for a door panel of a door whose movement is guided by a track, the release mechanism comprising:a bracket attachable to the door panel; a guide member being adapted to travel along the track as the door opens and closes; and a first member disposed on the bracket and adapted for selective engagement with the guide member to selectively place the guide member in an operative position and a dislodged position, wherein the guide member in the operative position is adapted to engage the track, and the guide member in the dislodged position is adapted to disengage the track, wherein the first member is frangible to release the guide member upon the first member breaking at a predetermined level.
  • 2. A release mechanism for a door panel of a door whose movement is guided by a track, the release mechanism comprising:a bracket attachable to the door panel; a guide member being adapted to travel along the track as the door opens and closes; and a first member disposed on the bracket and adapted for selective engagement with the guide member to selectively place the guide member in an operative position and a dislodged position, wherein the guide member in the operative position is adapted to engage the track, and the guide member in the dislodged position is adapted to disengage the track, wherein a first portion of the first member is able to selectively snap into and out of engagement with the guide member by virtue of a slot in the guide member.
  • 3. The release mechanism of claim 2, wherein the slot runs substantially parallel to the first portion of the first member.
  • 4. A release mechanism for a door panel of a door whose movement is guided by a track, the release mechanism comprising:a bracket attachable to the door panel; a guide member being adapted to travel along the track as the door opens and closes; a first member disposed on the bracket and adapted for selective engagement with the guide member to selectively place the guide member in an operative position and a dislodged position, wherein the guide member in the operative position is adapted to engage the track, and the guide member in the dislodged position is adapted to disengage the track; and a second member selectively insertable through a hole in the bracket to engage the guide member, such that the second member being inserted in the hole maintains the guide member in the operative position.
  • 5. The release mechanism of claim 4, wherein the first member and the second member are integrally joined to each other to comprise a unitary U-shaped piece.
  • 6. A release mechanism for a door panel of a door whose movement is guided by a track, the release mechanism comprising:a guide member being pivotally mounted to the door panel and being adapted to travel along the track as the door opens and closes; and a first member disposed on the panel and adapted for selective engagement with the guide member to selectively place the guide member in an operative position and a dislodged position, wherein the guide member in the operative position is adapted to engage the track, and the guide member in the dislodged position is adapted to disengage the track, wherein the first member is able to selectively snap into and out of engagement with the guide member by virtue of a slot in the guide member.
  • 7. A release mechanism for a door panel of a door whose movement is guided by a track, the release mechanism comprising:a guide member being pivotally mounted to the door panel and being adapted to travel along the track as the door opens and closes; a first member disposed on the panel and adapted for selective engagement with the guide member to selectively place the guide member in an operative position and a dislodged position, wherein the guide member in the operative position is adapted to engage the track, and the guide member in the dislodged position is adapted to disengage the track; and a second member disposed on the panel and being adapted for selective engagement with the guide member, wherein the first member and the second member are integrally joined to each other to comprise a unitary U-shaped piece.
  • 8. A release mechanism for a door panel of a door whose movement is guided by a track, the release mechanism comprising:a bracket attachable to the door panel; a guide member being adapted to travel along the track as the door opens and closes; and a retainer selectively movable to a first position and a second position, wherein the guide member is able to returnably break away from the bracket when the retainer is in the first position, however the retainer in the second position prevents the guide member from returnably breaking away, wherein the pin in the second position extends along a slot in the guide member.
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