This invention relates to a combination of a device for the retention of the bolt shoot of an emergency exit door and a bolt shoot.
It is known that in many buildings, in particular those which are open to the public, the provision of special safety doors which can be opened easily from at least one side in the case of emergency, is often required. Doors of this type, which are also called "panic exits", are, for example, required for emergency exits in public buildings. Some locks used for these emergency exit doors are fitted with bolt shoots which slide vertically within the actual door; the bolt shoots, operated by special spring-loaded devices, are designed to fit into a special hole in the doorframe. The bolt shoots are moved into the lowered (open) position by means of an external mechanism (for example a panic bolt push-bar). An example of such an anti-panic system is known from WO 83/01644.
Such locks are often fitted with a retention device for holding the bolt shoot in the lowered position when the door is open. The retention device is usually moved by means of a mobile part between a withdrawn position inside the door area and an active position projecting from the door, for example adjacent to the bolt shoot.
When the door is closed, this mobile part is pushed down by coming into contact with the door head and the retention device is deactivated. When the door is opened this mobile part is sprung into the active, projecting position and retains the bolt shoot. Obviously, then the door is closed and the mobile part comes into contact with the door head, it is pushed into the lowered position again and frees the bolt shoot.
Retention devices already in use are not however without drawbacks which limit their effectiveness. In particular, some of them are of too large a size, and are not always acceptable in proportion to the dimensions of the door and its frame. Other models of retention devices require a great deal of precision during mounting to avoid preventing correct operation, which can lead to increased costs and risk of malfunction. For example, there have been complaints that the mobile part can jam in the closed position inside the bolt shoot guide, which may be manufactured with a slightly widened shape.
It is an object of the present invention to provide a retention device in which the above disadvantages are reduced or substantially obviated.
It is a further object of the invention to provide a retention device with a simple conception, sure reliable operation and versatile application.
The present invention provides a combination of a bolt shoot of an emergency exit door and a device for the retention of said bolt shoot, the device comprising a lever unit mounted for rotation about a horizontal axis between a lowered position and an active raised position, biasing means for biasing the lever unit into the active position; latch means formed on the lever unit and located in front of the bolt shoot according to the hand of the door, and adapted to project above the door when the lever unit is in the active position; characterised in that said lever unit further comprises a catch unit mounted on the lever unit which is adapted in the active position to engage a toothed section of the bolt shoot to prevent it from moving upwards.
An embodiment of a retention device according to the invention will now be described with reference to the accompanying drawings in which:
The retention device (1) has a box-type housing (3), which is of an inverted U-shape, and has a hole (4) on the upper side (3a), through which the bolt shoot (2) passes freely.
This bolt shoot (2) is moved vertically in known manner by a suitable spring-loaded mechanism which is not illustrated.
Its upper end (2a) fits into a special socket (5) in the door head (6). The bolt shoot (2) is also guided by a collar (7) mounted on the outside of the housing (3).
Inside the housing (3), an oscillating lever unit (8) is mounted for rotation above a horizontal axis, by a pivot (9) which is mounted between the sides (3b) of the housing (3).
The free end of the lever unit (8) forms a latch (10) which extends upwards, in the median vertical plain of this lever (8), forming a bracket which holds the bolt shoot (2). The latch (10) is located in front of the bolt shoot (2), according to the hand of the door (indicated with an A in the illustration).
As will be further described later, in the active position, part of the end of the latch (10) protrudes from an opening (11) on the top side (3a) of the housing (3). This end section of the latch (10) forms an inclined plant (10a) which is opposite to the door hand A.
During rotation, a catch unit (13) attached to the lever unit by means of a transverse pin (12) also rotates above the pivot (9). The catch unit (13) comprises a bent U-shaped element and, in the active position, is adapted to engage a toothed section (14) of the bolt shoot (2) to prevent it from sliding upwards.
The toothing (14) on the bolt shoot (2) has a serrated profile, comprising a series of downwardly pointing conical teeth. The catch unit (13) is used to engage these teeth with the front edge of its underside (13a), which works essentially as a pawl.
The catch unit (13) and the lever (8) are moved together by a torsion spring (15) which is wound round the pivot (9) and is at one end hooked on to a bend (16) on the upper side (3a) of the housing (3). At the free end, the spring (15) acts on the rear edge of the underside (13a) of the catch unit (13), pushing the catch unit (13) into the active position.
In operation, when the door is opened by moving the bolt shoot (2) downwards, the latch (10) is no longer retained in its lowered position by the contact of its tip with the door head (6). The lever (8) can therefore rotate into the raised active position under the pressure of the spring (15). In this position, the pawl formed by the catch unit (13) engages one of the conical teeth of the serrated section (14) of the bolt shoot (2), locking the bolt shoot in the lowered position, against the force of the spring acting on the bolt shoot, as shown in Figure 1.
When the door is closed, the device moves in the opposite direction to A; the inclined plane (10a) of the latch (10) comes into contact with the edge of the door head (6) and is therefore compelled to withdraw. The lever (8) thus rotates into the lowered position, against the spring (15), freeing the bolt shoot (2) from the catch unit (13) and the bolt shoot (2) moves upwards into its slot (5) as shown in Figure 2.
In summary, this embodiment of a device according to the invention provides an excellent solution to the problem of the retention of emergency exit bolt shoots. It should be noted in particular that the location of the latch (10) in front of the bolt shoot (2) results in a reduction in overall dimensions, particularly with regard to the transverse axis, and makes easy, rapid mounting possible, since great precision is not required.
The device also has a very simple structure, which is an advantage for both effectiveness and manufacturing costs, as well as being very sturdy, so as to ensure adequate duration even when used continuously.