This application claims the benefit of provisional patent application No. 60/309,093 filed Jul. 31, 2001.
The field of the invention pertains to double doors that close together without a door frame in between. Normally the active door includes handles and a latch to provide for opening and closing the active door. Thus, at the intermediated handle elevation the passive door includes a strike plate and recess for the latch. The passive door may also include a separate strike plate and recess for a dead bolt at the intermediate level.
At the top corner of the passive door directly above the intermediate elevation strike plate is a vertically movable bolt engageable with a strike plate and recess in the door frame. Extended, the vertically movable bolt prevents opening of the passive door unless the active door is first opened releasing the cam actuator for the vertically movable bolt. In certain applications such as fire doors a bimetallic link will be included in the vertical bolt mechanism to prevent opening of the passive door in the event of high temperatures beyond the door.
Whether a steel door or a wooden door a considerable amount of door structure must be removed at the top corner to accommodate the vertical bolt mechanism. As a result this corner may be significantly weakened in routing out or cutting the door structure without damaging the door surfaces.
With a view toward avoiding significant damage to the passive door structure and simplifying installation of the vertical bolt mechanism the following mechanism configuration has been developed.
The new vertical bolt mechanism and installation that avoids damage to a door corner configuration comprises a vertical bolt case of tubular shape and a horizontal tubular transfer case. The mechanism is substantially contained within the bolt case and transfer case.
In the installation in the door the bolt case and transfer case require only two major holes in the door top and edge, each major hole being well spaced from the door corner and each major hole being directed perpendicular to the other. Installation requires insertion of the bolt case through the hole in the top of the door and the transfer case through the hole in the edge of the door. The two cases come together to form an L-shape within the door with the internal mechanism of each joined in engagement. Routing or cutting out of the inside of the door at the corner is thus avoided.
As shown in
The override guide 20 is contained within a transfer box 22 and is urged by an override spring 24 toward the top of the transfer box 22 as shown. A bimetallic strip 26 riveted 28 to the outside of the bolthead case 14 bends through a slot 30 in the case upon heating thereby preventing the bolt head from being retracted. A return spring 21 surrounds the bolthead 16 and threaded rod 18 and engages the underside of the D-hole guide 23 and the top of the transfer box 22.
The horizontal transfer mechanism 12 comprises a transfer case 32 containing a cam 34 rotatable about a pin 36. One end 38 of the cam 34 engages the bottom of the transfer box 22 and the other end 40 of the cam 34 engages a cam actuator and transfer slide 42 which in turn extends beyond a cover plate 44 and the door edge 46.
As is shown in
As illustrated in
The sheet metal door of
As is apparent the sheet metal door could have a variety of configurations with or without recesses that will accommodate the two-piece automatic bolt without disturbing or weakening door corner 68.
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