Closure fasteners – Bolts – Emergency operating means
Reexamination Certificate
1998-05-18
2004-08-24
Estremsky, Gary (Department: 3677)
Closure fasteners
Bolts
Emergency operating means
C292S172000
Reexamination Certificate
active
06779819
ABSTRACT:
BACKGROUND
This invention relates to an exit device having an elongated securing member, and more particularly to an exit device including a press bar on the inside of a door. When the press bar is pushed, it retracts the securing member so that the door can be opened.
State and federal codes have required that exit doors for public buildings be equipped with devices so that occupants exiting a building can press a panic bar or press bar to actuate the latchbolt of the door. Such pressing—as opposed to turning a handle or knob—is natural, particularly with persons escaping a building in a panic or an emergency situation.
Devices of this sort are well known, an example being disclosed by the U.S. Pat. No. 4,796,931 to George E. Heid. The Heid patent describes the linkages between the press bar and a latchbolt which is pivotally mounted adjacent the open end of the door.
Such structures have been designed to function under extreme conditions such as, for example, a group of people rushing to exit a smoke-filled building. A large number of such persons arriving at a closed door can exert a great outward force on the door and the exit device.
A standard exit device test by Underwriters Laboratories replicating such conditions involves exerting a horizontal outward force of 250 pounds against a closed door to test the exit device installed thereon. A further test during the application of the 250 pound force described above, requires that the press bar operate at a force of less than
50
lbs. This press bar force augments the 250 pound force mentioned above so that the total outward force on the latch can be up to 300 pounds. To counter this enormous force in the opening direction, designers of exit devices have avoided the preferred, more secure reciprocating deadbolt due to the high lateral friction generated under such conditions, and have adopted pivoted latchbolts.
In other words, while rectangular or square deadbolts, as known in the lock industry, offer better strength and security, they require a substantial force to slide them to retracted position under the above extreme conditions because of the large perpendicular forces acting on the bearing surfaces. Because failure of an exit device to open could be catastrophic, the preference for square or rectangular deadbolt-type locking members has been cast aside for the easier-opening pivoted latchbolt. The latchbolts have strike-engaging latching surfaces which are curved or beveled, thereby easing the resistance to retraction in the keeper as the door and exit device are pressed outward, but exerting lateral forces when the door is under pressure which separate the door and the frame thereby reducing door security. As a result, doors equipped with pivoted latchbolts have been more vulnerable to vandalism. Also, in fire situations in which enormous heat has warped the door and frame, pivoted latchbolts have been known to fail and pop open during fire tests.
For the foregoing reasons there is a need for an exit device which provides the security of a deadbolt while at the same time being operable under conditions of high outward force.
SUMMARY
An exit device for a door comprising a securing member assembly overcomes the aforementioned problems through the provision of an elongated securing member, such as a deadbolt or the like, for extending into a keeper mounted adjacent a free end of the door, the elongated member moveable longitudinally from an extended position to a retracted position; a pivoting member having a peripheral surface, the peripheral surface engaging a surface of the elongated securing member as the pivoting member pivots for retracting and supporting the elongated securing member from a direction opposite the direction the door opens; and means for actuating the pivoting member for moving the elongated member from the extended to the retracted position, the elongated member returning to the extended position when the press bar is released.
The actuating means of the securing member assembly may comprise, for example, a press bar assembly operatively connected to the pivoting member or elongated member whereby the press bar, when pressed, will move the elongated member longitudinally from extended to retracted position. The pivoting member serves as an anti-friction bearing roller to shoulder the inward force of the elongated securing member during its retraction as the door is pushed open and the elongated securing member is pressed hard outward against its keeper in the door frame.
Further, the pivoting member may further comprise a keeper-engaging surface for engaging a keeper and pivoting the pivoting member to retract the elongated securing member as the door is closed. The pivoting member also serves as an anti-friction device as the door closes to retract the elongated securing member as the keeper-engaging surface on the pivoting member forces the pivoting member to pivot and in turn drives back the elongated securing member.
The securing member assembly for the exit device of the present invention may further comprise means for effecting deadlocking of the elongated securing member in the extended position and means for canceling deadlocking of the elongated member.
Using an elongated securing member gives a mortise-lock degree of security to a surface-mounted exit device.
Accordingly, it is an object of this invention to provide an exit device having an elongated securing member, such as a deadbolt or the like, as its securing member.
A further object of this invention is to provide an exit device having a deadbolt as its securing member wherein the deadbolt is mounted adjacent a free end of the door for longitudinal movement from an extended to a retracted position.
A still further object of this invention is to provide an exit device having a deadbolt as its securing member which does not require substantial force to move the deadbolt from the extended to the retracted position.
Another object of this invention is to provide an exit device having a deadbolt as its securing member for a door having a press bar on the inside of the door to actuate the deadbolt.
Still another object of this invention is to provide an improved exit device having a deadbolt as its securing member which will meet the aforementioned requirement of opening under conditions of great outward force on the door and exit device.
A related object of this invention is to provide an improved exit device for a door having a press bar on the inside of the door to actuate the deadbolt, the door opening with minimal pressure on the press bar despite great outward force on the door.
Yet another object of this invention is to provide an exit device having an improved degree of security.
Similarly, an object of this invention is to provide an improved exit device which is less vulnerable to vandalism.
With more particularity, it is an object of this invention to provide an improved exit device having a deadbolt as its securing member with a deadlocking feature.
A feature of this invention is an elongated member, such as a deadbolt or the like, as the securing member of an exit device.
A further feature of this invention is a pivoting member which upon actuation drives the deadbolt into a retracted position.
A still further feature of this invention is linking means connecting the press bar and deadbolt whereby when the press bar is pressed the deadbolt will move longitudinally from extended to retracted position.
Another feature of this invention is the pivoting member, generically referred to herein as a retractor blade, which serves as an anti-friction bearing roller to bear the force against the deadbolt in the door opening direction during retraction of the deadbolt as the door is pushed open and the deadbolt is pressed against its keeper.
A related feature of this invention is a bearing surface on the retractor blade bearing against a surface of the deadbolt for progressively rolling along the deadbolt surface as the deadbolt is retracted.
Still another feature of this invention is a keeper-engaging surface on the retractor blade
Estremsky Gary
Johnston Michael G.
Moore & Van Allen PLLC
Yale Security Inc.
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