DE20110970U1 - Construction and construction of stairs and pedestals made of wood-based materials - Google Patents

Description

Reference number: 201 10 970.0
My reference: FHV ERKt
Applicant / Owner: Ernst Kwiatkowski

Description Structure and construction of stairs and landings made of wood materials

In general , stair treads and landings made of wood-based materials are traditionally made from several solid wood scantlings glued together in the respective length or, more recently, from solid wood cuts that are finger-jointed or butt-jointed on the front side, also from several scantlings glued together to the required total width.

The geometry of the glue joint can be straight or wavy; the latter increases the glue surface and thus the load-bearing capacity of this type of connection. The disadvantage here, however, is the increased use of material.

These products are classified under the general term solid wood panels . (EN 13017 - 2:2000 p.3; DIN 18334: 2000 -12 p.15)

Steps and platforms made of solid wood panels ( 1 ), usually made from high-quality local hardwood or imported wood, have a very high material price component. An additional disadvantage is the unavoidable natural shrinkage and swelling behavior of solid wood when there are higher humidity fluctuations than intended (according to DIN 18 334 HF = 9% + / - 3% during installation), and thus not entirely unproblematic for the manufacturer's guarantee.

The advantages of solid wood panels are their good performance characteristics of natural, undamaged wood and the low cost of further edge processing to produce the finished product once the geometry of the individual steps (straight or spiral) has been determined.

(1) is still the most widely used product in step and staircase construction, with the better qualities of the suitable wood species reaching a very high price level and therefore, despite the available quantities, there are too few consumers.

Strong multi-layer plywood panels can also be used.

(DIN 68 705 - 3 to 5)

Steps and landings made of multi-layer plywood panels ( 2 ) are also very expensive and are therefore rarely used, since an additional layer of joined sliced veneer from the higher-quality stair timbers must be applied to both sides of the relatively expensive base plate - plywood. This layer is usually based on the appearance of solid wood (continuous strips or butt-jointed short pieces).

Additional costs arise from the necessary processing of the vertical edges by gluing so-called "foreign edges" all around. In the step area, according to DIN regulations, a 6 mm thick foreign edge must be glued on, which can be visually disturbing if the wood structure of the edge does not match the veneer on both sides.

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Page - 2 - Description

Advantages are the almost impossible shrinkage of the carrier plate due to the layer structure and the high static values of the individual stages. The applicant is not aware of any competent manufacturers of (2).

Furthermore, several variants are known with the carrier plate made of chipboard (according to DIN 68 763) with a double-sided knife veneer layer of approx. 0.6 mm to 2.5 mm thickness, depending on the manufacturer, to form so-called veneered composite panels with a symmetrical structure. They achieve very good static values due to the multi-layer structure and have very low shrinkage and swelling behavior.

( DE-PS 32 41 685 C2 , DE - PS7 20 791 , DE-GM 69 30539 ) The visible top layer is also modeled on solid wood by joining the individual veneer strips together and gluing them onto the chipboard ( like 2 )

Steps and landings made of veneered composite panels ( 3 ) have a not inconsiderable price advantage over (1), especially with a veneer layer of 0.6 to approx. 1.5 mm thickness, which does not correspond to DIN 18 334 : 2000 -12 p. 15. The performance characteristics are limited, especially with high foot traffic, since sanding and repainting the parts is hardly possible with this thin wear layer!

The price advantage of this product outweighs the limited usability.

With the minimum thickness of 2.3 mm of the wear layer after sanding required by DIN 18 334, the material is indeed stronger, but due to the technical processing of the so-called thick veneers, it can be assumed that the inner wood structure has been broken. This also results in a significant reduction in quality compared to (1), as after prolonged use and care, grey hairline cracks appear in the step surface, which have filled up with foreign particles (dust/cleaning agents, etc.).

The disadvantage here again is the machining with "foreign edges", depending on the geometry of the step parts ( as 2).

Thus, (3) only achieves a certain market share due to the price advantage over (1), since an alternative product that approximately combines all the advantages of (1 to 3) cannot yet be offered in the sector "steps and platforms made of wood-based materials".

The total thickness of the steps and landings from (1) (2) or (3) varies between approx. 40 - 65 mm, depending on the structure, type and purpose of the finished staircase systems (DIN 18065).

Page - 3 - Description

The invention specified in claim 1 is based on the problem of creating a panel structure for steps and platforms which combines the advantages of solid wood panels (1) with the advantages of composite panel technology ( 2 or 3 ) without limiting the industrial applicability of the invention, and which achieves financial benefits for manufacturers and consumers, particularly when using types of wood that are well suited for steps and platforms.

At the same time, the new symmetrical 5-layer structure achieves good statics and significantly reduces the problematic shrinkage / swelling behavior of solid wood.

This problem is solved with the features listed in claim 1 and illustrated in Fig. 1 and Fig. 2.

The invention also ensures that the steps/platforms in the walking area are technically and visually similar to a solid wood product (1). The visible tread of the steps is no longer destroyed by a foreign edge subsequently glued to the tread edge area, regardless of its thickness.

This advantageous property of the finished steps / landings is specified in claim 2 and shown in Fig. 3.

The invention for which protection is sought in the claims is therefore

1. the general base plate structure, with the wood material combinations shown in Fig. 1 and 2, from which individual steps and platforms can then be manufactured, and

2. the design of the longitudinal edges on the base plates according to Fig. 3, which guarantee a closed tread in the heavily used walking area of the stairs.

Claims (2)

1. Structure and construction of stair treads and landings made of wood materials, characterized in that the raw or base plates required for this according to Fig. 1 have a symmetrical structure according to Fig. 2, are coated with at least 4 mm thick, joint-glued ( 3 ), continuous ( 1 ) or butt-jointed wooden cover layers ( 2 ) made of calibrated solid sawn veneers, and have a transverse wooden layer ( 9 ) of at least 1.2 mm thick between the carrier plate and the two cover layers.
The length ( 4 ) or width ( 5 ) as well as the total thickness ( 6 ) of the raw panels can be varied and is determined by the technical capabilities of the manufacturer and the intended use.
The carrier plate in Fig. 2 can consist of chipped and re-glued wood material ( 7 ), e.g. chipboard, OSB board, MDF/HDF boards, or of solid wood bars ( 8 ), glued or laid loosely. 2. Stair steps or landings according to protection claim 1, characterized in that the longitudinal edge/external edge ( 10 ) glued on one or both sides according to Fig. 3 is to be worked in such a way that the self-contained wooden covering layer ( 1 ; 2 ) on both sides is retained.