FI104357B - Spring molding of wood laminate - Google Patents

Abstract

The slat consists of a number of veneers of the same width glued together such that the width of the slat increases in the middle. Beneath the sprung slat's neutral zone (b) between the veneer strips (1-5), and symmetrical with the centre is a layer of at least one ply (7,8,9) which is much thinner than the veneer strips and shorter than the sprung slat. The layer consists of coloured sheets stepped lengthwise and made of resin-impregnated cellulose paper or glass fibre fabric, 0.2 to 0.5 millimetres thick.

Description

I 104357

Laminated spring strip - Fjäderlist av trälaminat

The invention relates to a laminate spring strip of thin plywood strips glued to one another and having a thickness increasing from the ends of the spring strip toward its center.

Such spring moldings are known (DE-U-67 50 118). They are used to make beds, deck chairs, armchairs or the like. The spring moldings are known in the art to be slightly curved to provide the required prestress and are mounted on the furniture with the convex side facing upwards. It is hoped that these spring bars will have progressive suspension characteristics, i.e., that the spring force will increase as the deflection increases.

Known spring strips consist of a plurality of interleaved plywood strips, some of which extend over the entire length of the spring strip, some of which are shorter and arranged stepwise and symmetrically with respect to the center of the long strips to form a sheet spring arrangement.

With such a spring strip, the thickness of the plywood strips is 1.0 to 1.7 mm and the number of plywood strips extending over the entire length of the spring strip is 5 to 7.

: Y: There are some drawbacks to these well-known spring moldings. One disadvantage is that they are difficult to manufacture because the thickness of the plywood extruded stack is not ...: not uniform and cannot be extruded into compression molds which have a regular pattern. . 20 curvature. Another disadvantage is that the transition points between the long ply and the short ply plywood are stepped so that the spring strips cannot be sufficiently compressed in the region of the ends of the short plywood layers. This disadvantage could be eliminated by the ends of the short plywood ply would, however, involve an undesirably higher manufacturing cost.

Another disadvantage of the known spring lists is that when packing the stack, the same difficulties are encountered because the thickness difference between the center and the ends of the stack is quite large. This also entails significant costs in connection with transport.

• · • * '. . The technical problem underlying the invention is, therefore, to provide a strut strip of laminated wood • · · * · '30 with progressive striking properties, the manufacture of which does not present the difficulties described above.

This technical problem is solved according to the invention by providing a layer of at least one lamellae, which is substantially thinner than the plywood strips and shorter than the spring strip, symmetrically centered below the neutral plane of the spring bar between the plywood strips.

Since, in the case of the spring strips of the invention, the lamellae between the plywood strips are substantially thinner than the actual plywood strips, there is no problem of joining between the lamellae ends and the surfaces of the plywood strips.

Preferred details of the invention are set forth in claims 2 to 6. The invention will now be explained by means of an exemplary embodiment shown in the figure.

The figure shows - not to scale - a sectional view of the layer structure of the spring bar according to the invention. In the exemplary embodiment shown, each long line represents a strip of plywood having a thickness of 1.0 mm to 1.7 mm extending over the entire length of the spring bar. In the structure shown, the spring strip consists of five strips 1-5 of plywood. The neutral plane of this structure is illustrated by the dashed line 6. Below it are provided shorter lamellae 7, 8 and 9 having a thickness of about 0.2 to 0.5 mm and having different lengths. They consist of resin impregnated cellulose paper or fiberglass fabric of high tensile strength which may be colored.

The suspension characteristics of the spring bar can be adjusted by the number of blades and their dimensions. Singers of different colors can express the different characteristics of the strings of strings.

• · * »« · «· · •« • # · • • • • • • • • • • •

«I

• · · • «• ·« «· ·« »I ·

• M

»· · • * · • • • • • • m! · I ♦ · \; / ·;

Claims (6)

1. Made of turin, interlaced glued veneer strips made of 5 layer wood, which the thickness of the spring mold increases from its ends towards the middle part, characterized in that a neutral part (6) between the veneer strips (1-5) is arranged below the spring strip (1-5). symmetrically, of at least one slat (7, 8, 9) formed, layers which are substantially thinner than the veneer strips and shorter than the spring strip. 10 Spring strip according to claim 1, characterized in that the layer is formed by several longitudinally stepped slats (7, 8, 9). Spring strip according to claims 1 and 2, characterized in that the slats 15 (7, 8, 9) are arranged between two adjacent veneer strips (4, 5). Spring strip according to claims 1 and 2, characterized in that the slats (7, 8, 9) are arranged in the spaces between the spring strips (3, 4, 5) advantageously. . breathe. .Ϊ '' 20 • · 5. Spring strip according to any of the preceding claims 1-4, characterized c ·. , ·. thereof, that the slats (7, 8, 9) are formed of resin impregnated cellulose paper or I / I glass fiber web, the thickness of which is 0.2-0.5 mm. • · · · »M Spring bar according to claim 5, characterized in that the slats (7, 8, 9) have been colored. • · · • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·