Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1998-10-19
2001-02-13
Dye, Rena L. (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S116000, C428S117000, C428S131000, C428S138000, C052S402000, C052S783100
Reexamination Certificate
active
06187401
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a double-walled body with cover panels between which spacers are arranged.
Double-walled bodies of the type mentioned here can be used wherever there is a need for structures of low mass and a high degree of rigidity, for example for fast-moving machine tables. Previous lightweight structures have been produced by a sandwich construction method, but the rigidity of these does not always satisfy requirements. Also known are extremely machining-intensive integral construction methods with high-outlay cast or welded structures, which are complex and expensive to produce.
SUMMARY OF THE INVENTION
The object of the invention is thus to provide a double-walled body which has good rigidity properties and is relatively straightforward and cost-effective to produce.
In order to achieve this object, a double-walled body which has spacer between the walls is proposed. It is distinguished in that the spacers are designed as cylinders, in particular tubes, of which the cylinder axes run orthogonally with respect to the cover-panel surfaces, in that one set of tubes (first tubes) is of a length which corresponds to the clear width between the cover panels, and in that another set of tubes (second tubes) engages in, or through, apertures in the cover panels by way of the end regions in each case, and in that the interior of at least some of the second tubes accommodates fastening means, in particular threaded bushes. The task of the first tubes is to fix the distance between the cover panels while the double-walled body is assembled. This is a straightforward way of ensuring that the cover-panel surfaces are aligned precisely parallel to one another at a desired distance apart. The second tubes are longer than the first tubes, and this means that their end regions at least extend into, and preferably engage through, the apertures in the cover panels, thus connecting the cover panels to one another. The cover panels and the tubes can thus be assembled quickly and easily without any other auxiliary means, for example spacers and clamping elements. Following assembly of the double-walled body, fastening means which serve for receiving, for example, clamping and/or retaining elements are introduced into the second tubes. The double function of the second tubes, namely connecting the cover panels and receiving fastening means, eliminates further machining operations, for example providing receiving and/or threaded bores in the double-walled body, in order to provide possible fastening means for subassemblies, for example a drive unit, as a result of which the double-walled body can be produced in a straightforward and cost-effective manner.
A preferred embodiment of the double-walled body is one in which the tubes are supported against one another by way of their lateral surfaces. The tubes are arranged between the cover panels such that each tube is adjacent to at least one further tube. The arrangement of the tubes with respect to one another may be such that their lateral surfaces are in contact with one another. This additionally increases the bending and torsional strength of the double-walled body.
A particularly preferred embodiment of the double-walled body is distinguished in that the end regions of the tubes are joined to the corresponding cover panel. This achieves a high degree of rigidity for the entire panel and tube structure. Joining takes place by means of an integrally bonding joining method, welded joints being preferred as a result of their high bending and torsional strength and of the optimum flux of force. If the double-walled body is subjected to relatively low loading then soldered joints and/or adhesive bonds are also possible. Laser welding is the proposed welding method since, as a result of their concentrated heat intensity, lasers have only a small active region, this resulting in joining with low degrees of warpage and stressing. The use of numerically controlled welding robots, which can be controlled by means of a CAD/CAM coupling, makes it possible to automate assembly of the double-walled body, with the result that the production costs are reduced. It is also conceivable for the cover panels and the tubes to be joined to one another in a frictionally locking manner, at least in some regions of the double-walled body. This improves, for example, the handling of preassembled cover panels and tubes, that is to say cover panels and tubes which have not yet been joined to one another.
Also preferred is an embodiment of the double-walled body in which the tubes are cut to length from bar stock by a cutting method, in particular laser cutting, and are used for setting up the double-walled body without any further machining. The clean, precise, that is to say planar, cut surface of the laser-cut tubes means that further machining, for example deburring, is not necessary, with the result that the tubes can be fitted directly. It is also possible here to use numerically controlled cutting machines in order to reduce the costs. The term “cutting method” also covers machining methods, for example cutting into, or cutting off, the bar stock by means of a suitable cutoff tool in a lathe.
Also preferred is an embodiment of the double-walled body which is distinguished in that, at their ends, the tubes each have planar end surfaces which run orthogonally with respect to the cylinder axes, in particular tube axes. This ensures that the cover-panel surfaces are positioned flush on the end surfaces of the first tubes, and that the distance between the cover panels at any point is constant within a narrow tolerance range.
A particularly preferred embodiment of the double-walled body is distinguished in that the fastening means are retained in the second tubes by means of a filling of plastic. It is possible for the remaining annular space between the inner lateral surface of the tubes and the outer surface of the fastening means to be filled with a suitable, hardening foaming or casting compound. This means that the fastening means are quickly and cost-effectively fixed in position on the double-walled body.
Also preferred is an embodiment of the double-walled body in which the bore of the second tubes has a thread and/or is designed as a close-fit bore, preferably with a press fit, into which correspondingly designed fastening means can be respectively screwed or inserted. The thread and the close fit can be produced before the double-walled body is assembled, for example before the operation of cutting to length from bar stock. This eliminates the need for reclamping of the tubes and of the double-walled body, as a result of which the production times are reduced.
Also preferred is an embodiment of the double-walled body in which the tubes are designed as polygonal tubes. Since the tubes are supported against one another when subjected to bending and/or torsion, the planar surfaces on the exterior of the tubes cause the forces which act on the tubes when the latter are subjected to loading to be distributed, as a result of which the surface pressure is reduced. This makes it possible to use tubes with relatively thin walls, as a result of which the overall weight of the double-walled body is reduced.
Finally, also preferred is an embodiment of the double-walled body in which the space between the two cover panels has a foamed-plastic filling. This quasi-embedding of the tubes in a filling prevents noise-inducing and disrupting vibrations, which may be caused, for example, by the first tubes, and the penetration of dirt. Furthermore, the bending and torsional strength of the double-walled-body structure is increased.
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patent: 630464 (1963-07-01), None
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patent: 4
Gringel Martin
Heisel Uwe
Blüco-Technik Blümle KG
Dye Rena L.
Ostrolenk Faber Gerb & Soffen, LLP
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