Static structures (e.g. – buildings) – Composite prefabricated panel including adjunctive means – Sandwich or hollow with sheet-like facing members
Reexamination Certificate
2000-09-07
2002-05-07
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Composite prefabricated panel including adjunctive means
Sandwich or hollow with sheet-like facing members
C052S232000, C052S001000, C052S784110, C052S784120, C052SDIG005
Reexamination Certificate
active
06381917
ABSTRACT:
BACKGROUND OF THE INVENTION
Numerous safety requirements are imposed on lift or elevator doors, which requirements have to be observed during construction of the so-used door panels. Thus, for example, the heat transmission through the lift door must be minimal, wherein the door panel shall withstand a large and, in particular, canted mechanical load at one side. Known door panels (cf DE 19645517) used for lift doors have been formed from two walls, i.e. a front wall and back wall, which are welded together. Through one or more bent profile to members of the back wall an air space between the front wall and back wall is maintained, which ensures a sufficient heat-shielding property.
The connection of the two walls is carried out by spot welding in corresponding inset locations, so that the least possible contact of the two oppositely-disposed walls is produced by the connection.
The rigid connection of the front wall with the back wall does indeed ensure on the one hand a permanent rigidity, but in the case of the heating of door panel, for example in the case of fire, the door panel is warped by different heat expansions predominantly due to temperature difference between the front wall and back wall. The warping of a lift door in the case of fire hampers the opening of the door which may be jammed due to the warping and thus represents a certain risk to safety. Moreover, maximum permissible gap widths, which are prescribed for the purpose of preventing breakthrough of flame, may be exceeded.
BRIEF DESCRIPTION OF THE INVENTION
The object of the invention is therefore to provide a door panel which satisfies all requirements for rigidity of a lift door with respect to mechanical loading, running smoothness and sound transmission while avoiding the above-mentioned disadvantages.
The foregoing and other objects and purposes are met by a door panel according to the invention in which connecting means are provided between the front wall and back wall which release under the action of heat. In addition, at least one heat-resistant connection is provided.
The heat-resistant connection ensures that the lift door panel does not fall apart in the presence of heat and fire and thus remains able to be manipulated as an entirety, while the connection which is releasable under the action of heat between the front wall and back wall enables a relative movement between the two walls in the case of fire. Warping under the action of heat is thereby avoided as would be the case, due to different heat expansion, with a rigid connection over the entire area of the door panel.
A lift door constructed with door panels according to the invention accordingly cannot jam to the extent that is the case with conventional doors so that an easier manipulation is made possible and the permissible gap widths are not exceeded in the case of fire.
Preferably, the heat-resistant connection is arranged at an edge region of the door panel, which is not visible in the installed state of the lift door. Such an arrangement provides an improved appearance of the lift panel at its visible surfaces in comparison with known door panel constructions. Previously used weld points, for example, are difficult to conceal without costly further processing.
In an advantageous development of the invention an area gluing is provided for realizing the heat-releasable connection. The area gluing offers advantages with respect to production engineering, while properties can be realized which were previously able to be achieved only by weld points distributed over the area of the door panel, without large points of contact of the front wall and back wall. A corresponding high overall rigidity of the door panel overall can be achieved by way of the corresponding area connection created by the area gluing. The gluing moreover enables, through the use of an appropriate material between the two walls of the door panel, good sound and vibration damping with an area connection, without the front wall and back wall being in direct contact. Furthermore, a cold production process for construction of the door is possible with the assistance of a gluing step; the results of the gluing is a flat, largely distortion-free door panel which requires at the most minimal further processing.
In a particular embodiment of the invention the heat-resistant connection can be formed to be flexible to a certain extent. This enables, even with such a heat-resistant connection, a relative movement to compensate for different thermal expansions. Such a flexibility is possible in accordance with the invention, as the requisite high rigidity of the door panel can be substantially insured by the additional heat-releasable connection, such as the area gluing. Usual connecting means, such as rivets, screws, detent connections, spot welds or the like can be used for the heat-resistant connection.
Advantageously, the door panel according to the invention may be constructed to be merely double-skinned. The production and stockholding not only with respect to the variety of parts, but also with respect to the assembly of the door panel, are thereby substantially simplified over conventional door constructions.
Advantageously, an upper mounting, by means of which the door panel is able to be fastened to a suspension carriage, may be provided. By means of such a suspension carriage the door panel can be displaced in a guided manner in lateral directions, so that, for example, a telescoping lift door can be constructed from several door panels traveling adjacent to or into one another.
In a particularly advantageous embodiment of the invention the heat-resistant connection between the front wall and the back wall is provided in the region of the upper mounting. This heat-resistant connection can, for example, be combined with the fastening to the suspension carriage. The fastening to the suspension carriage and the connection between front wall and back wall thus can be undertaken with one and the same screw connection Such an arrangement has the effect that, on release of the connection which is not heat-resistant in the case of fire, both front wall and back wall remain fastened in a suspended manner at the suspension carriage.
Advantageously the upper mounting of the door panel is formed by integral shaping of the front wall and/or back wall. The cost in production of the door panel is thereby reduced and, in particular, the above-mentioned double-skinned mode of construction is favored.
The front wall and back wall may be tightened or clamped in the suspension carriage in the region of the upper mounting. The heat-resistant connection between the front wall and back wall is realized by this tightening or clamping in the suspension carriage, while the transverse rigidity of the door panel in the installed state is increased.
Advantageously, at least one bent longitudinal profile member portion is provided in the front wall and/or back wall. Such a bent longitudinal profile member, which can, for example, be made up with a right-angled or trapezium-shaped cross-sectional profile formed by stamping of one or both of the said door panel walls, considerably increases the stiffness of the door panel and can at the same time serve as a spacer between the walls. The bent longitudinal profile member is for that purpose preferably formed to be continuous over the entire length of the door panel so that corresponding bending moments which, for example, act due to mechanical loading in the middle region of the door panel are fully dissipated into the edge regions without weak points.
Advantageously, at least one bent transverse profile member, which at least partly engages over the bent longitudinal profile member, is provided in the edge region. Support of the bent longitudinal profile member on the transverse profile member thereby results upon the occurrence of bending stresses in the door panel and provides a further improvement of resistance to such stresses through improved bending stiffness.
Both the bent longitudinal profile member and the bent transverse profile member ca
Feistenauer Harald
Thielow Frank
A Phi Dieu Tran
Friedman Carl D.
Inventio AG
Schweitzer Cornman Gross & Bondell LLP
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