Movable or removable closures – With specified means to effect emergency release to closure
Reexamination Certificate
2000-07-13
2003-03-04
Strimbu, Gregory J. (Department: 3634)
Movable or removable closures
With specified means to effect emergency release to closure
C049S258000, C049S260000
Reexamination Certificate
active
06526695
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to automatic door assemblies. In particular, the present invention relates to a sliding door assembly having a damping device that provides controlled resistance to swinging movement of a panel during breakout.
BACKGROUND OF THE INVENTION
Sliding door assemblies known heretofore conventionally have a frame assembly with a pair of non-sliding panels mounted thereto and one or two sliding door panels that move in a generally rectilinear manner between opened and closed positions. The non-sliding panels are positioned such that they are on opposing lateral sides of the sliding panels when the sliding door panels are closed. During normal operation, a power-operated overhead door operator moves the sliding panel(s) between the opened and closed positions thereof.
Oftentimes, either the sliding panels, the non-sliding door panels, or both are provided with the capability to open outwardly in a swinging manner under an application of manual force to allow persons to pass through the door assembly during emergency conditions wherein the door operator is unable to open the sliding panel(s). This capability, referred to in the art as “breakout,” is usually required by state or local building codes as a safety measure for allowing exit from buildings during fires, power outages, and other such emergency situations wherein the door operator may be unable to function properly.
It has been known in the field of automatic door assemblies to provide the panels with breakout capability with a yieldable detent device for maintaining a breakout panel in its normal, non-breakout condition until a predetermined amount of force is applied to the panel. The amount of force required to move the panel in a breakout manner usually has a maximum set by local codes. However, once the panel has been moved out of its normal, non-breakout condition, these yieldable devices do not function to control the manner in which the panel continues to open.
To control the manner in which the breakout panel swings once breakout has begun and the panel is released from the above-described yieldable detent device, damping devices have been connected at one end to the top rail of the breakout panel and at the other end to the header that houses the door controlling unit. These devices are designed to provide controlled resistance to the swinging breakout movement of the panel. Specifically, these devices prevent the panel from being thrown open in an uncontrolled manner by persons seeking exit through the door assembly and also prevent high winds from acting on the panel and also throwing it open in a uncontrolled manner.
One example of a known damping device comprises a U-shaped track structure that defines a U-shaped channel and a rod with a plastic block on one end thereof. The track structure fixedly connects to the top rail of the door panel in the longitudinal direction thereof, the rod pivotally connects to the header of the door frame, and the rod and track structure are assembled together with the plastic block fit tightly in the U-shaped channel. As the panel is swung open during breakout, the plastic block slides within the U-shaped channel so that the friction between the block and the channel walls provides a controlled resistance to the panel's movement.
One problem with the use of these extendible and retractable devices can be appreciated from viewing FIG.
1
.
FIG. 1
is a schematic overhead view of a conventional door assembly
100
with a header
102
, a breakout panel
104
opened 90° from normal, and a damping device
106
for controlling the swinging movement of the panel
104
, such as the U-shaped channel and block arrangement mentioned above. The device
106
has a metal track
103
with interior surfaces and a plastic friction block
105
tightly received in the track
103
. The block
105
is mounted on a metal rod
107
and a spring
109
is disposed between the block
105
and the end of the track to resist the door panel's opening movements. The panel
104
is pivotally connected to the header
102
by pivot pin
108
. When a load is applied to the panel
104
, as indicated at F
L
, the pivotal connection between the rod
107
and the block
105
of the damping device
106
acts as fulcrum point. Also, the pivot pin
108
provides a fulcrum point. Accordingly, the application of load F
L
creates reaction forces at the pivotal connection between the rod
107
and the block
105
and on the pin
108
. These reaction forces are illustrated by the arrows shown in FIG.
1
.
It is to be understood that the reaction forces on the pivot pin may be created by structures other than an extendible door swing controlling device. For example, a shopping cart may become wedged between the breakout panel and the building exterior as the panel is being opened. Also, the breakout panel may contact a portion of the frame assembly as it approaches opening 180 degrees, thereby providing the panel with a leverage point. Thus, it could be broadly stated that these reaction forces are created as a result of a load that is applied to the breakout panel at a point distal the pivot pin which tends to pivot the breakout panel about a second point located intermediate the first point and the pivot pin.
Of particular concern in this arrangement are the reaction forces applied to the pivot pin
108
. In conventional panels, the bracket that carries the pivot pin
108
is only attached to the interior of the vertical side rail or stile. Thus, the forces applied to the pivot pin
108
will be transferred to and be borne by the stile. The problem with this is that most side stiles are thin-walled metal extrusions and may become deformed under the forces applied to the pivot pin
108
. Specifically, brackets that have been previously mounted inside side stiles are mounted by fasteners to only one side wall thereof with spacing provided between the bracket and the other side walls. As a result, when a force is applied to the bracket, this force is localized on the fasteners that mount the bracket. In addition, the spacing provided between the other side walls of the stile and the bracket allows the bracket to move under this force, thereby inwardly deforming the side wall to which it is mounted, particularly at the points where the fasteners are located. Permanent deformation of the side stile may result if the loads and reaction forces involved are high enough. One possible solution would be to use a stile with thicker walls. However, the costs of metal extrusions increase significantly as the wall thickness increases and likewise the overall weight of the panel increases.
In the above-described arrangement with the bracket mounted to one wall of the stile, the pin is normally extendible and retractable and a spring is mounted inside the bracket to bias the pin to its extended position. The advantage of this arrangement is that it makes the door panel relatively easy to install. Specifically, the installer retracts the pin, positions the door panel in place with the pin in alignment with its corresponding aperture on the door carrier or header, and then releases the pin for its spring-biased movement into the corresponding aperture.
Another prior art construction alleviates the stile deformation problem mentioned above with respect to the arrangement with the bracket mounted to a side wall of the stile. This second prior art construction is shown in FIG.
2
. This construction, generally indicated at
200
, comprises an upper bracket
202
that mounts to the sliding door panel carrier and a lower bracket
204
that mounts to the top rail of the door panel. The pivot pin
206
is fixed to the lower bracket
204
and pivotally mounted to the upper bracket by a ball bearing assembly
207
so that the upper and lower brackets
202
,
204
pivot relative to one another. When the door panel is assembled, the reaction forces discussed above are distributed to the top rail of the door panel in the longitudinal direction thereof. As a result, the problems associated wi
Pillsbury & Winthrop LLP
Strimbu Gregory J.
The Stanley Works
LandOfFree
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