Movable or removable closures – With means mounting closure for swinging – With latch or lock
Reexamination Certificate
2000-02-29
2001-07-17
Redman, Jerry (Department: 3634)
Movable or removable closures
With means mounting closure for swinging
With latch or lock
C292S004000
Reexamination Certificate
active
06260304
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to door structures.
2. Background of the Prior Art
A known door structure includes:
a first plate serving as fixed frame with an opening enclosed by a peripheral edge; and
a door connected pivotally to this first plate by at least one hinge construction such that with its peripheral zone the door can co-act sealingly with said peripheral edge;
which first plate carries a number of peripherally arranged clamps, which clamps are simultaneously rotatable by a collective operating mechanism with an operating handle and through rotation can co-act with the peripheral zones of corresponding non-round continuous holes in the door, which peripheral zones have for each clamp a contact surface inclining relative to the main plane of the door structure in the closed situation, which continuous holes have a form such that a clamp can pass therethrough.
The known door structure is used for instance in explosion-sensitive conditions, such as for instance in the extraction of fossil fuel, as well as for military applications, for instance on board military vessels.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a door structure which meets very high mechanical requirements and is nevertheless relatively light. The door according to the invention must be to a great extent fire- and explosion-proof. The explosion resistance must also be guaranteed if the door can be loaded in an explosion by a pressure wave which has a tendency to open a closed door.
With a view to the above stated objectives, the invention generally provides a door structure of the described type which has the feature that the door comprises a second plate which is strengthened with at least one beam welded to this plate and extending between two clamps situated on either side of the door;
the clamps are arranged symmetrically pairwise on rotation shafts;
the continuous holes in the door are correspondingly formed slotted holes;
each peripheral zone of a continuous hole in the door has two substantially symmetrically located, inclining clamp contact surfaces.
The at least one beam increases the bending stiffness of the plate. Should it be wished to achieve the same increased bending stiffness by increasing the plate thickness, the weight of the door would become considerably greater.
The two clamps arranged symmetrically in relation to each associated rotation shaft ensure a symmetrical load on said rotation shaft in the case of tensile strain. In contrast to usual clamps, there need hereby be no fear of bending of the rotation shaft in for instance explosion conditions. Such a known bending can result in a tightened clamp springing open. Partly for this reason the explosion resistance leaves something to be desired in known door structures.
A specific embodiment has the special feature that the door is generally elongate, the hinge construction extends in longitudinal direction and the or each strengthening beam extends in transverse direction. It is noted here that the strengthening beams are preferably arranged in a regularly distributed pattern.
In the case of a door whereof the peripheral zone is provided in the usual manner with a peripheral edge extending transversely of the main plane, strengthening beams can be omitted in the area of the end edges. The placing of the beams can then be limited to the middle zone of the door.
A preferred embodiment has the special feature that the second plate is substantially flat and the beam has a U-shaped profile, which beam is welded substantially wholly to this plate with the free end edges of the U. Of fundamental importance is that the beam contributes essentially over its whole length to the bending stiffness of the second plate. In this respect it is necessary that the connection between the U-beam and the plate is not brought about for instance by means of screws or spot welds but by a full welding of the free end edges of the U-profile fixedly to the plate.
In order to achieve the best possible explosion resistance, all potential passages must be blocked as effectively as possible. In this respect an advantageous embodiment can have the special feature that round the rotation shaft of the clamp is situated a filler piece which fits into the corresponding hole in the door.
In known door constructions is it usual for a continuous hole for a clamp to debouch freely into the opening present in the first plate. In the case of explosion load a bending of the door can hereby result such that the clamps leave the continuous holes via said debouchments. A variant of the structure according to the invention which does not have this drawback has the special feature that each continuous hole in the first door is wholly enclosed by material.
The door structure according to the invention is preferably embodied such that the clamps and the associated holes are placed symmetrically.
A preferred embodiment has the further special feature that the door structure consists substantially of metal, for instance steel.
The term “substantially” is understood to mean that the door construction may also comprise non-dominant components of a different composition. A door construction can for instance comprise thermal insulation material such as mineral wool. In addition, appropriate parts are generally provided with anticorrosive and protective coatings, while sealing means can for instance consist of rubber-like materials.
A specific choice for the door structure according to the invention entails the second plate consisting of steel plate with a thickness of 3-10 mm, in particular about 5 mm.
Another choice consists of the beam having a wall thickness of 2-8 mm, in particular about 4 mm, and consisting of steel with high yield point, for instance QSTE 420 with a yield point of ≧350 kPa.
A particular embodiment is further characterized by a neoprene rubber sealing ring which seals the door relative to the first plate in closed situation.
REFERENCES:
patent: 2511268 (1950-06-01), Schiff
patent: 3180303 (1965-04-01), Hamilton
patent: 4435921 (1984-03-01), Marin
patent: 4527760 (1985-07-01), Salacuse
patent: 4971369 (1990-11-01), Jean
patent: 5086587 (1992-02-01), Andrews
patent: 5129693 (1992-07-01), Schmitt
patent: 5199369 (1993-04-01), Meyer et al.
patent: 6101764 (2000-08-01), Guy-Paul
patent: 3341544 (1985-06-01), None
patent: 0552505 (1993-07-01), None
patent: 00895 (1913-01-01), None
patent: 1013693 (1965-12-01), None
patent: 2181777 (1987-04-01), None
patent: 2195958 (1988-04-01), None
patent: 2224072 (1990-04-01), None
Beheermaatschappij H.D. Groeneveld B.V.
Redman Jerry
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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