Joining films/foils of intermediate layers

Abstract

The invention generally relates to intermediate layers (shim-type stacked foils/films) as adjusting elements for mechanical structures.

Claims

1. Edge-bonded or laminated shims comprising a plurality of sheets of the same or different kinds, characterized in that the sheets are bonded to one another by welding and are bonded together on at least one edge on one or several sites by welding.

2. The shims according to claim 1, characterized in that the sheets are bonded together on at least one edge by at least one weld line.

3. The shims according to claim 1, characterized in that the sheets are bonded together on at least one edge by a plurality of weld lines.

4. The shims according to claim 1, characterized in that the sheets are further bonded together with an adhesive on part of the area, the full area, and/or peripherally.

5. The shims according to claim 1, characterized in that the sheets comprise metal foils, polymer sheets, fabrics, fiber composite materials, especially of glass, carbon, ceramic or aramid fibers, or mixtures of the above mentioned materials.

6. A process for preparing edge-bonded or laminated shims comprising providing a plurality of sheets of the same or different kinds, characterized in that the sheets are bonded to one another by welding; cutting or punching individual sheets out at first in the form of the end product; stacking said individual sheets on one another or in the form of a staircase; fixing the layers, and welding said sheets together at the front surface or peripheral edge.

7. The process according to claim 6, characterized in that the areas and/or edges are welded together using a radiation source.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) In a first embodiment, the above object of the invention is achieved by edge-bonded or laminated shims comprising a plurality of sheets of the same or different kinds, characterized in that the sheets are bonded to one another by welding.

(2) Welding means (according to EN 14610 and DIN 1910-100, as well as within the meaning of the present invention) the non-detachable bonding of components with the application of heat and/or pressure, with or without welding additives, wherein additives are rather not employed according to the invention.

(3) According to the invention, the necessary welding energy is supplied from outside, wherein welding auxiliaries, such as protective gases, welding powders or pastes may facilitate welding, or even make it possible. Welding, also within the meaning of the present invention, is performed by supplying heat to melt the material or by supply of heat and additional exposure to force (pressure) on the stack of the sheets. Thus, the sheets are connected to one another in the edge region of the shims by the welded connection. In contrast to book spine bonding, however, no separate adhesive is applied here, but the sheets are connected to each other by fusion.

(4) It is particularly preferred within the meaning of the present invention that the welding connection is created by laser welding, because joining can then be effected with a high welding speed, a narrow and lean shape of the weld, and with low thermal warping. It is known that laser welding or laser beam welding is usually performed without supplying an additional material. The laser radiation is focused by means of an optical system, in which the laser beam has a typical diameter within a range of a few tenths of millimeters, which generates very high energy concentrations when the laser employed possesses the typical powers of a few kilowatts of laser power. Accordingly, it is possible according to the invention to bond several sheets together by an extremely thin weld on at least one outer edge of the stack of sheets by welding. One or several weld lines may be present on at least one edge, and in addition, a plurality of weld lines may also be present on at least one edge or one peripheral area. Thus, a stable connection of the individual sheets is achieved, so that the sheets can be peeled off simply.

(5) In addition to the welding connection of the individual sheets according to the invention, it is of course also possible to additionally adhesive-bond the sheets, which may consist of the same or different materials and/or have different thicknesses, on part of the area or on the full area and/or peripherally.

(6) Any sheets can be employed as the material for the sheets of the shims as long as they can be welded. This means that individual parts can be welded together to form components of the desired quality by the common effect of the suitability of the material to be welded (welding tendency), a construction suitable for welding (welding safety) and a suitable organization of manufacture (possibility to weld). Accordingly, metal foils, polymer sheets, fabrics, fiber composite materials, especially of glass, carbon, ceramic or aramid fibers, or mixtures of the above mentioned materials are particularly preferred according to the present invention.

(7) Another embodiment of the present invention relates to a process for preparing the above defined edge-bonded or laminated shims. This process according to the invention is characterized in that edge-bonded or laminated shims comprising a plurality of sheets of the same or different kinds are bonded together at first by welding.

(8) Thus, while the first steps of the preparation of the shims according to the invention correspond to those of the prior art, these are welded together on at least one side or edge after the individual sheets have been stacked. Accordingly, it is possible according to the invention to weld together not only cuboid or cubic shims, but also sheets stacked in a staircase manner, in which part of the tread is also bonded to the riser of the next sheets.

(9) It is particularly preferred within the meaning of the present invention to use a radiation source, especially a laser radiation source, for welding the areas and/or edges.

(10) Another embodiment of the present invention relates to the use of the shims, for example, in vehicle construction, aeronautics, electrical engineering or measuring technology, especially in generator or transformer construction.

(11) It is also possible to employ the above defined shims for electrical insulation.

(12) The shim according to the invention is a time- and cost-optimized alternative to known shims.

(13) In a preferred embodiment of the present invention, it is possible to treat a loose or compressed stack of sheets peripherally with a radiation source.

(14) Thus, shims are bonded to one another only in partial areas of the sheets, which is done only on the circumference, i.e., the front surfaces, of the sheet. In a staircase-shaped embodiment of the shim, the step is optionally also welded, which is usually not interfering, however.

(15) This kind of bonding according to the invention enables a flexible radius design for curved surfaces whenever two curved surfaces must be kept at a distance in applications. Also, different types of materials can be bonded together with a wide variety of advantageous properties for the application, such as: avoiding contact corrosion, introducing sliding layers, integrating thicker interior material sheets, which introduce stiffness and higher pressure strengths and offer advantages in cost by reducing the number of layers. The shims according to the invention conform particularly well to curved surfaces, especially if there is no area-based connection between the sheets.

(16) Therefore, it is particularly preferred to cut or punch out the individual sheets in the form of the end product as known from the prior art, in order to stack them exactly on one another. Subsequently, the layers are fixed, and then, the previously defined front surface(s)/peripheral edge(s) are treated. The connection should be elastic enough to offer mechanical strength for a low use area, and to resist the shocks from handling and transport.