Fireproof shaft door for elevators

A fireproof shaft door for an elevator installation has an improved heat insulation towards the shaft side in the case of a fire at the floor side of the door. A door is filled with heat insulating spaces and heat insulating mat and is positioned at the floor side of a framework which is carried by a door suspension. The framework is horizontally displaceable on a roller and is guided at a lower edge by a sliding guide engaging a recess in a threshold. Horizontal spars, which are provided with ventilation apertures, are attached to the door box at the shaft side. Heat insulating plates are attached to the spares to cover the shaft side of the framework. A first hollow space is formed between the door box and the heat insulating plates and functions as natural chimney in which fresh air circulates. A vertically extending recess is formed in a closing edge of the door box to form a second hollow space in which fresh air circulates when the door is closed.

BACKGROUND OF THE INVENTION 
The present invention relates generally to elevator installations and, in 
particular, to a fireproof door for an elevator shaft. 
The German patent document DE-A1 25 12 536 discloses a box-like elevator 
shaft door, in which cooling air feed openings are provided in the lower 
region of the metal door cover plate at the shaft side and cooling air 
outlet openings are provided in the upper region of the same. Thereby, the 
metal door cover plate at the lobby side is cooled uniformly and the metal 
door cover plate at the shaft side is protected against excess heating. 
The French patent document FR-A1 2 610 311 discloses an elevator shaft door 
which has a frame and which serves as a carrier for a respective 
insulating panels arranged at the lobby side and at the shaft side. The 
frame itself is filled with an insulating mat. A fire resistance of two 
hours is achieved with this door construction. 
A disadvantage of the known fireproof shaft doors is that they do not meet 
the more severe regulations of certain countries in respect of the 
permitted temperature gradient between the fire side and cool side. 
SUMMARY OF THE INVENTION 
The present invention concerns a fireproof shaft door for an elevator 
installation having an improved heat insulation towards the shaft side in 
the case of a fire at the floor side of the door. A door box is filled 
with heat insulating spaces and heat insulating mat and is positioned at 
the floor side of a framework which is carried by a door suspension. The 
framework is horizontally displaceable on a roller and is guided at a 
lower edge by a sliding guide engaging a recess in a threshold. Horizontal 
spars, which are provided with ventilation apertures, are attached to the 
door box at the shaft side. Heat insulating plates are attached to the 
spares to cover the shaft side of the framework. A first hollow space is 
formed between the door box and the heat insulating plates and functions 
as natural chimney in which fresh air circulates. A vertically extending 
recess is formed in a closing edge of the door box to form a second hollow 
space in which fresh air circulates when the door is closed. In an 
alternate embodiment, the spars can extend vertically. 
The present invention solves the problem of the known fireproof doors and 
provides specified rigidity, fire resistance and heat insulation. 
The advantage achieved by the present invention is that, in the case of 
fire at the lobby or floor side, the elevator shaft remains available to 
the fire service as an escape path due to the improved heat insulation at 
the shaft side. A further advantage is that, in spite of improved fire 
protection properties, the total weight of the shaft door can be kept 
small. Another advantage is that heat bridges between the heat insulating 
layers can be avoided to a large extent. Another advantage is that the 
usual fire protection sluices in front of the elevator doors at each floor 
are not necessary.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A fire can occur in an area F adjacent an elevator shaft door opening, the 
opening being bounded at a bottom edge by a floor 1 of a lobby 2, at an 
upper edge by a lintel beam 3 and laterally by a pair of spaced apart door 
posts 4 as shown in the FIGS. 1 and 2. The lintel beam 3 and the door 
posts 4 form a shaft opening of an elevator shaft 5 and are backed by a 
hollow door frame 6. The door frame 6 is filled with a heat insulating 
substance 7 and is attached to the lintel beam 3 by a horizontally 
extending flange 8 and to the door posts 4 by a pair of vertically 
extending flanges 9. In order to accommodate construction and mechanical 
deviations, a heat insulating sealing bead 10 is provided between the door 
frame 6 and the lintel beam 3 and between the door frame 6 and the door 
posts 4. 
The upper horizontal portion of the door frame 6 is connected with a 
horizontally extending fastening rail 11. A roller guide 12 is attached to 
and extends downwardly from a transverse carrier 13. The carrier 13 has a 
lower end attached to the door frame 6 and extends upwardly toward the 
rail 11 to an upper end and then rearwardly toward the elevator shaft 5. 
The rearwardly extending portion of the carrier 13 is connected between 
the rail 11 and the roller guide 12. A door suspension 14 extends 
downwardly from a roller 15 which is positioned in the roller guide 12. A 
vertically extending cover 16, having a layer of heat insulating material 
attached to a rear surface thereof, spans the roller guide 12 and the door 
suspension 14 adjacent to the elevator shaft 5. The lower horizontal 
portion of the door frame 6 is terminated at the shaft 5 by a horizontally 
extending, U-shaped threshold carrier 17 having a vertically extending 
metal cover plate 18 attached to a rear leg thereof. Positioned in a 
groove formed in the threshold carrier 17 is a sliding guide 20. A 
vertically extending guide carrier 21 includes a guide blade 22 having an 
upper edge attached to a shaft door as explained below and a lower edge 
attached to the sliding guide 20. 
A vertically extending framework 23 is attached along an upper edge thereof 
to and supported by the door suspension 14. A door box 24 is attached to 
the frame 23 on the lobby side or the fire side and, as illustrated in the 
FIG. 2, is filled with alternating heat insulating spaces 25 and heat 
insulating mats 26 in a layered sequence beginning at the lobby side with 
a space 25, then a mat 26, then a space 25, and then a mat 26. A plurality 
of horizontally extending spars 28, each having a plurality of ventilating 
apertures formed therein, are attached to a rear surface of the box 24. 
One of the spars 28 at the upper end of the box 24 is attached to the door 
suspension 14 and another one of the spars 28 at the lower end of the box 
24 is attached to the upper edge of the guide blade 22. Thus, the 
framework 23 is guided in movement along the roller guide 12 by the guide 
20 sliding in the threshold 19. 
Attached to the spars 28 and facing the shaft 5 are heat insulating plates 
29. In a variation or alternate embodiment, the spars 29 can extend 
vertically. A first hollow space 30 is bounded by the box 24 and the heat 
insulating plates 29. The space 30 acts as natural chimney, in which fresh 
air denoted by A circulates. The door box 24 is formed from two leaves 
which abut at vertically extending closing edges, each of the closing 
edges having a recess 31 formed therein. The recesses 31 are aligned with 
the spaces 25 closer to the shaft 5 and face one another to form a second 
hollow space 32 which serves as a chimney when the doors are closed. 
In accordance with the provisions of the patent statutes, the present 
invention has been described in what is considered to represent its 
preferred embodiment. However, it should be noted that the invention can 
be practiced otherwise than as specifically illustrated and described 
without departing from its spirit or scope.