DOOR STRUCTURE

Abstract: A door structure (1) comprises: a first plate (2) serving as fixed frame with an opening (4) enclosed by a peripheral edge (3); and a door (7) connected pivotally to this first plate (2) by at least one hinge construction (5, 6) such that with its peripheral zone (8) the door can co-act sealingly with said peripheral edge (3); which first plate (2) carries a number of peripherally arranged clamps (9), which lamps are simultaneously rotatable by a collective operating mechanism (10) with an operating handle (11) and through rotation can co-act with the peripheral zones (12) of corresponding non-round continuous holes (13) in the door (7), which peripheral zones (12) have for each clamp (9) a contact surface (14) inclining relative to the main plane of the door structure (1) in the closed situation, which continuous holes (13) have a form such that a clamp can pass therethrough. The door structure (1) has the characteristic that the door (7) comprises a second plate (15) which is strengthened with at least one beam welded to this plate (15) and extending between two clamps (9) situated on either side of the door; the clamps (9a, 9b) are arranged symmetrically pairwise on rotation shafts; the continuous holes (13) in the door are correspondingly formed slotted holes; each peripheral zone of a continuous hole (13) in the door (7) has two substantially symmetrically located, inclining clamp contact surfaces (14a, 14b).

Description: DOOR STRUCTURE The invention relates to a door structure, comprising: 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. Such a door structure is known. 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. 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 streng- thening 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 stiff- ness 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 materi- al 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- con- sisting 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. The invention will now be elucidated with reference to the annexed drawings . In the drawings : figure 1 shows a perspective view of a door structure according to the invention; figure 2 shows a perspective view of the door structure according to figure 1 from the other side; figure 3 shows on larger scale a partly broken-away perspective view of a clamp; figure 4 is a partly broken-away perspective view on enlarged scale of the clamp according to detail IV of figure 3; figure 5 is a longitudinal section through the clamp according to figure 4; and figure 6 shows the clamp according to figure 4 in an alternative embodiment on still further enlarged scale. The figures show a door structure 1. This door structure 1 according to the invention comprises a first plate 2 serving as fixed frame with an opening 4 enclosed by a peripheral edge 3 and a door 7 pivotally connected to this first plate 2 by at least one hinge construction 5, 6 such that with its peripheral zone 8 door 7 can co- act sealingly with said peripheral edge 3, which first plate 2 carries in this embodiment ten peripherally arranged clamps 9, which clamps 9 are simultaneously rotatable by a collective operating mechanism 10 with an operating handle 11 and can co-act through rotation with peripheral zones 12 of corresponding non-round continuous holes 13 in door 7, which peripheral zones 12 have for each clamp 9 a contact surface 14 inclining relative to the main plane of door structure 1 in the closed situation, which continuous holes 13 have a form such that a " clamp 9 can pass therethrough. Door 7 comprises a second plate 15 which is strengthened in this embodiment with three beams 16, 17, 18 which are welded to this plate 15 and which extend between two clamps situated on either side of the door. Clamps 9 are constructed such that they each consist of two sub-clamps, designated for instance 9a and 9b in figure 4, which are arranged symmetrically pairwise on a rotation shaft 16. The continuous holes 13 in the door are slotted holes, the form of which by and large corresponds with the form of clamps 9, and are so much larger that the clamps can pass through the holes . Each peripheral zone 12 of a continuous hole in door 7 has two substantially symmetrically located, inclining clamp contact surfaces 14a, 14b. It is noted that the angle at which the inclining clamp contact surfaces 14a, 14b extend can be freely chosen within certain limits. What is essential is that clamps 9a, 9b can be placed in wedging co-action with the inclining surfaces 14a, 14b in question. In this respect attention is drawn to the fact that various functional modifications are possible. The clamps themselves can for instance be provided with inclining surfaces co-acting with corresponding non- inclining elevations. By rotating the clamps the same operation is then obtained, i.e. by displacing handles 11 a rotation of the clamps takes place such that owing to the inclining contact surfaces a slight swinging of the door takes place relative to the fixed frame, whereby the desired clamping can be ensured. It is further noted that the clamps can be arranged on the door, in which case the continuous holes and the associated contact surfaces in the zones around the holes form part of the fixed frame. Door 7 is generally elongate, the common axis of hinges 5, 6 extends in vertical longitudinal direction and strengthening beams 16, 17, 18 extend in horizontal transverse direction. The second plate 15 is substantially flat and each beam has a U-shaped profile and is welded substantially wholly to this plate 15 with its free edges 19. Figures 3, 4, 5 and 6 show clearly that around- the rotation shaft 16 of a clamp 9 is situated a filler piece 20 fitting into the corresponding hole in door 7. This filler piece can be of any suitable material. Filler piece 20 can for instance be manufactured from metal, but a suitable plastic can also be considered. In respect of rt 0 J P P 0 ζ t to rt J X Φ ra TJ --• PJ Ω Φ - ≤ tr Φ P Φ tr ^ rt tr Φ 3 o P φ 0 P φ ra ra Ω *< P- d drically formed contact surfaces 23a and 23b come into clamping contact with the respective contact surfaces 14a and 14b, The situation obtained hereby is shown in figure 5. Figure 5 shows in broken lines the free situation and in full lines the closed situation of the door structure . Contact surfaces 14, 14a, 14b can form an integral part of the separate elements 23 which are welded to plate 7 and have the continuous holes 13, but can also be embodied as protrusions separately arranged on these elements 23. It is noted that the angle of inclination of contact surfaces 14 in figures 4 and 5 differs from this angle in figure 6. *****

Claims: CLAIMS 1. Door structure (1), comprising: a first plate (2) serving as fixed frame with an opening (4) enclosed by a peripheral edge (3) ; and a door (7) connected pivotally to this first plate (2) by at least one hinge construction (5, 6) such that with its peripheral zone (8) the door (7) can co-act sealingly with said peripheral edge (3); which first plate (2) carries a number of peripherally arranged clamps (9) , which clamps (9) are simulta- neously rotatable by a collective operating mechanism (10) with an operating handle (11) and through rotation can co-act with the peripheral zones (12) of corresponding non-round continuous holes (13) in the door (7), which peripheral zones (12) have for each clamp (9) a contact surface (14) inclining relative to the main plane of the door structure (1) in the closed situation, which continuous holes (13) have a form such that a clamp (9) can pass therethrough; characterized in that the door (7) comprises a second plate (15) which is strengthened with at least one beam welded to this plate (15) and extending between two clamps situated on either side of the door; the clamps (9a, 9b) are arranged symmetrically pairwise on rotation shafts; the continuous holes (13) in the door are correspondingly formed slotted holes; each peripheral zone (12) of a continuous hole (13) in the door (7) has two substantially symmetrically located, inclining clamp contact surfaces (14a, 14b) . 2. Door structure as claimed in claim 1, characterized in that the door (7) is generally elongate, the hinge construction (5, 6) extends in longitudinal direction and the or each strengthening beam (16, 17, 18) extends in transverse direction. 3. Door structure as claimed in claim 1, characterized in that the second plate (15) is substantially flat and the beam (16, 17, 18) has a U-shaped profile, which beam (16, 17, 18) is welded substantially wholly to this plate (15) with the free end edges (19) of the U. 4. Door structure as claimed in claim 1, characterized in that round the rotation shaft (16) of a clamp (9) is situated a filler piece (20) which fits into the corresponding hole in the door (7) . 5. Door structure as claimed in claim 1, characterized in that each continuous hole (13) in the door (7) is wholly enclosed by material. 6. Door structure as claimed in claim 1, characterized in that the clamps (9) and the associated holes (13) are placed symmetrically. 7. Door structure as claimed in claim 1, characterized in that the door structure (1) consists substantially of metal, for instance steel. 8. Door structure as claimed in claim 1, character- ized in that the second plate (15) consists of steel plate with a thickness of 3-10 mm, in particular about 5 mm. 9. Door structure as claimed in claim 1, characterized in that the beam (16, 17, 18) has a wall thickness of 2-8 mm, in particular about 4 mm, and consists of steel with high yield point, for instance QSTE 420 with a yield point of ≥ 350 kPa. 10. Door structure as claimed in claim 1, characterized by a neoprene rubber sealing ring (21) which seals the door (7) relative to the first plate (2) in closed situation. *****

Inventors: GROENEVELD DIRK HUGO, GROENEVELD, DIRK, HUGO
Applicants: GROENEVELD DIRK HUGO, GROENEVELD H D BEHEER, BEHEERMAATSCHAPPIJ H.D. GROENEVELD B.V., GROENEVELD, DIRK, HUGO
Application year: 1998
Main classification: E05C9
IPC codes: B63B43, E05B17, E05B63, E05C9, E06B5