DE1183353B - Vacuum deep drawing process for covering upholstered workpieces with a covering material and a device for its implementation - Google Patents

Description

Vacuum deep drawing process for covering padded workpieces with a coating material and device for its implementation. The invention relates on a vacuum deep drawing process for covering padded workpieces with a cover fabric, in which the upper pull fabric is under the overpressure of the atmosphere pressed against vacuum against the surface of the workpiece and with the edges this is glued. The invention also relates to a device for Implementation of this procedure.

In a known method or those known in connection therewith Device for covering upholstered workpieces with a covering material in a vacuum deep drawing process serves to hold the workpiece on a workpiece carrier one on the workpiece carrier remote side lockable and evacuable chamber.

The chamber is in this case by means of a piece of the covering material to be applied self lockable.

By evacuating the chamber, the covering material is exposed the external atmospheric pressure is pressed against the workpiece, whereupon a hot welding or gluing process for attaching the cover to the workpiece follows. The edges of the Covering material are clamped, and one between the workpiece and the clamping point The section of the outer covering material comes to rest on parts of the device and cannot be used for the actual coating of the workpiece itself. This Section must therefore after the upper covering material has been glued to the workpiece be cut away. This means a considerable waste of material and makes the method or the operation of the device is uneconomical.

But there is not just a need, an economically working one To create a device for covering padded workpieces, but also that Covering of padded workpieces with gas-permeable covering material enable.

This is not possible with the known device, since the coating itself forms the closure of the vacuum chamber and must therefore be impermeable to gas.

The invention is based on the object of a method or a To create a device for covering upholstered workpieces with a covering material, which are characterized by the advantages mentioned. This is done according to the invention achieved by the fact that the covering material is cut to size and is placed loosely on the workpiece and the space surrounding the workpiece, the to form the vacuum chamber, with a reusable one that is separate from the cover material airtight membrane is closed.

When this method is used, it is no longer the same as with the known ones Process required that the blank of the coating material substantially over his final dimensions beyond being oversized by up to one around the edges to reach the clamping point lying on the device.

There is thus no significant waste of material. Since the The blank of the coating material no longer even closes the evacuable chamber forms, this does not need to be impermeable to gas, so that this process is much more generally applicable than the known method.

As in the known process, the cutting of the cover material is pulled over the lower edge of the material by placing the workpiece on a Support is placed that is smaller than the lower surface of the workpiece, can, according to a further advantageous feature of the invention, the membrane together the cut over the lower edge of the workpiece The advantage of saving material by eliminating a high proportion of waste is particularly noticeable weight.

Advantageously, you can with the Uberziehvorgang on the In the middle part of the covering material, additional area of the workpiece to be covered to the atmospheric pressure exert mechanical pressure. This is particularly of Advantage when the workpiece itself is made of elastically deformable material which must be expected that it will decrease in flexibility in the course of use and shrinks. The use of additional mechanical pressure has the advantage of that even with a later reduction in flexibility and shrinkage of the material the workpiece remains under sufficient tension in the covering material, so that it does not wrinkle.

Preferably, when using a thermosetting adhesive, the Membrane can be heated for the upper drawing process. The heating temperature is preferably at about 65 to 1500 C.

An apparatus for carrying out the method according to the invention can in addition to the known for receiving the workpiece on a workpiece carrier serving, lockable and evacuable on the side facing away from the workpiece carrier Chamber as a closure of this chamber an airtight provided as part of the device, have elastically deformable membrane, the cover material when open Chamber can be inserted between the workpiece and the membrane.

The work table and / or the membrane of the device can be heated be, and if the work table can be heated, a guided through the work table, be placed on this lowerable carrier, which is used to carry the workpiece. A device designed in this way is particularly suitable for coating workpieces, where the edges of the covering material in the edge areas of the lower surface of the workpiece are to be glued.

When the workpiece is supported on a non-lowerable support is, can in the direction of the envelope of the cover material around the lower edge of the Workpiece movable pressing devices can be provided, which are used to press the serve to be glued to the underside of the workpiece edges of the covering material These pressing devices, which, when actuated, are located on the edges of the lower The surface of the workpiece forming folds of the membrane occur, serve to increase the contact pressure in the area in which the edges of the covering material with the the lower surface of the workpiece are to be glued.

The invention is illustrated below with reference to the drawings of exemplary embodiments explained in more detail.

Fig. 1 is a partially sectioned perspective view a device according to the invention in its working position; F i g. 2 is a Section through parts of the device in an operational position; F i g. 3 and 4 are sectional perspective views of fabricated in accordance with the invention padded items; Fig. 5 shows in perspective, partially in section, a Another example of a device according to the invention; Figs. 6 and 7 are sectional views further modifications of the invention; Figs. 8 and 9 are sectional views of pressing devices to support the gluing process; F i g. 10 is a Angular view of such a pressing device.

As in particular in FIG. 1 and 2 of the drawings the device in the simplest case from a vacuum table as work table 11 and an elastomeric membrane 14, which is in a peripheral flange or a frame 15 a and 15b is fixed by means of screws 15c.

The membrane can be made of any flexible elastomer with sufficient Be heat resistance and gas impermeability. A latex with good elongation both at ambient temperature as well as at elevated temperatures can be used.

However, the use of a membrane made of vinylidene fluoride hexafluoropropylene rubber copolymer is preferred, a highly heat-resistant rubber, sold under the> Viton <(trademark) Du Pont de Nemours & Co., Inc.

Such membranes can withstand temperatures of 1500 C and above Withstand continuous operation and temperatures of 2600 C if not used continuously.

The work table 11 has a raised workpiece carrier in the middle 12. A base plate 16 of a workpiece made of cardboard, wood, fiber or the like rigid material, the area of which is larger than that of the workpiece carrier 12, is with protruding edge placed centrally on its surface. When the workpiece carrier 12 and the base plate 16 are circular, the diameter of the latter is for example about 5 cm larger than that of workpiece carrier 12. The lower surface of the base plate 16 is in the area adjoining its vertical edges up to approximately 2l / s cm inwardly covered with adhesive. A core that corresponds to the desired Form of the finished piece a sheet 17b of resilient cushioning material, e.g. Latex foam rubber, and a second layer 17a of such a cushioning material may have, is placed centrally on the base plate 16. This is followed by the Upholstery core 17 a, 17 b a blank 18 made of cover material placed, which is slightly larger than the surface of the base plate 16, so that the} that of the blank is over the vertical edges of the base plate protrude when centered over the cushion core 17 a, 17 b is placed. The lower surface of the blank 18 is in the over the Edges of the base plate 16 protruding portions 19 coated with adhesive.

The core 17 a, 17 b made of cushioning material can be made of any conventional Upholstery material, e.g. B. latex, rubber foam, urethane foam, vinyl foam, hair pads, rubber coated hair, wood wool, cotton, wadding, wire and insulated Wire springs or combinations of these materials exist. Any material that is resilient can be used as a cushion. As a tYbetzugsw fabric can any natural or synthetic fabric, e.g. B. cloth, leather, coated fabrics or permeable coated fabrics, vinyl films, rubber-synthetic resin mixtures etc., be vexdet.

Any heat-setting, thermoplastic adhesive can be used as the adhesive and pressure-binding adhesives can be used. A suitable warminP dendes adhesive is an aqueous dispersion of polyvinyl acetate synthetic resin, which about 55 to 6001.

Has solids in dispersion, and a suitable one pressure-setting The adhesive is neoprene phenol cement (US Pat. No. 2,918,442).

If the parts 16 and 17 a and 17 b and the blank 18 on the Workpiece carrier 12 are placed on the work table 11, the membrane 14 is on the Work table 11 is lowered and the air between the membrane 14 and the surface the work table 11 is sucked off by means of vacuum lines 23.

Instead of the membrane 14 stretched in a frame up to the work table 11 lower can advantageously be a flange or raised frame 20 on the Surface of the vacuum table 11 provided and fastened by means of screws 22, on which the inner part 15 b of the membrane frame 15 rests upon lowering. This raised frame 20 runs around the workpiece carrier 12 on the work table 11 and the workpiece 16, 17 a, 17b composed of parts 16, 17 b and 18, 18. The membrane 14 presses the lower surface of the blank 18 into contact with the adhesive-coated portion 19 of the lower surface of the base plate 16. Tensioning the membrane around the workpiece 16, 17 a, 17 b, 18 causes the blank 18 pulled tight and glued to the underside of the base plate 16 in section 19 will.

Of course, the workpiece according to the invention can also be used directly on a vacuum work table 11 with a flat surface without a raised workpiece carrier 12 can be produced. In this case the glue is instead on the bottom the base plate 16 is applied to parts of the vertical side surfaces thereof, and the blank 18 is due to the action of the membrane 14 only on these vertical Surface parts attached.

If a hot-melt adhesive, for example a polyvinyl acetate adhesive water-based, is used, the membrane 14 may prior to lowering the same be heated on the work table 11. The heated membrane alone is sufficient around the adhesive provided in section 19 on the underside of the base plate 16 to stick.

If necessary, the raised workpiece carrier can also be used a heating element 24 can be arranged. In general, heating the membrane is sufficient to a temperature between 65 and 150 ° C.

The vacuum is maintained until the adhesive has set, for which 1 minute is generally sufficient. Then the vacuum is released, the membrane 14 is raised and the finished workpiece provided with the coating taken.

In the modified embodiment according to FIG. 6 that have a lifting and lowerable workpiece carrier, a heating plate 25 is provided, which on the upper surface of the work table 11 is placed. This heating plate is used for Activation of the on the underside of the base plate 16 of the workpiece and to the Edges of the blank 18 provided adhesive. The heating elements of this heating plate 25 are denoted by 24.

The workpiece carrier 45 has the shape of a piston that is slidable is passed through the heating plate 25 and the work table 11 and with a Piston rod 30 is firmly connected. With the help of this piston, which is in the middle of the The lower surface of the base plate 16 engages the workpiece, the latter is about the upper surface of the heating plate 25 can be raised and can be lowered to this area. For the production an airtight seal between the piston and the heating plate 25 is used Locking ring 35.

The workpiece has the same structure as that of FIG. 1 and 2, and there could be a second layer in addition to the single layer 17 shown a be provided. To generate the for pulling the cover cut on Vacuum lines 23 are provided for the vacuum required for the workpiece.

The vacuum is generated when the workpiece is raised. When the full vacuum is reached, the piston-like workpiece carrier 45 is by means of the piston rod 30 lowered; until the lower surface of the base plate 16 under the Pressure of the membrane 14 against the heating plate 25 is pressed.

This pressure is used to glue the blank 18 and the underside of the base plate 16.

As shown in Fig. 7, this pressure can be supported by an arrangement consisting of a piston rod 36 and a press foot 38. This press foot 38 can advantageously according to the finished shape of the coated Workpiece be shaped. This press foot 38 can also advantageously be a radiant heating source The recesses shown in FIG. 7 serve to accommodate them 37.

When using a Gnind plate 16 made of a softer and more flexible material Material, it may be desirable to use a composite workpiece carrier 45, of how F i g. 7 shows of two spaced apart by means of spacers held flat plates 45 a and 45 b is formed, on the top of which the base plate 16 of the workpiece rests.

As shown in FIG. 8 and 9 can be seen to improve the adhesive effect effective pressure jaws 41 may be provided during the gluing process.

These jaws are advantageously made up of several regular ones Formed over the circumference distributed parts 41 a and 41 b. According to FIG. 8 is everyone Pressure jaws 41 rigidly on a plate 40 which can be actuated by means of a piston rod attached. The piston rod is connected to a piston 48, which is under the influence one through lines 46 resp.

47 introduced pressure medium in a chamber 39 plays.

In the embodiment according to Figure 9, the parts of the pressure jaw 41 rigidly attached to one of several angle levers 44, the free end of which in a socket 42 common to all angle levers 44 by means of a ball joint is stored.

The socket 42 is on a socket 43 of the piston rod 36 of the press foot 38 slidably arranged independently of the last ren. F i g. 3 shows a perspective Section through a finished padded object, the surface of which has grooves 17 c.

For example, such grooves in the layer 17 b of the cushioning material, e.g., foam rubber, may be provided and the blank 18 vacuum formed and have lists protruding into the grooves of the cushioning material. Instead of this can be a blank made of thermoplastic material during the covering process be heated so that under the effect of the vacuum and the pressure of the membrane form protruding strips in the blank in the grooves of the cushioning material.

Such patterns can also be used before the actual pull-up process by gluing the blank 18 with a layer 17 b of the upholstery, for example by means of electricity or by supplying heat, under pressure.

In all cases in which the covering material is impermeable to air air ducts 16 a (Fig. 3) must be provided in the base plate 16. It is enough Usually five to six narrow holes are sufficient.

F i g. 4 shows one in perspective and in section sprung upholstered article made according to the invention. the with 17 a designated layer consists of metal springs on the base plate 16 by means any adhesive can be attached. The free end of the springs is covered by a layer of coarse canvas over which the upholstery material in a layer 17 b, for example made of foam, matted hair, etc., placed The cover is formed by a blank 18 again. Recommended for such objects it turns out to use feathers whose length is from the center to the edge of the object is progressively less and the desired shape of the finished article is equivalent to.

F i g. 5 shows an embodiment in perspective a device according to the invention as independently superposed on legs 11 a Unit. The heat required for the bonding process is provided by infrared lamps 33 supplied in a housing 34. On movable side rods 28 here are shown as racks, a carrier 29 is arranged, which the membrane 14 wears.

This arrangement can be raised and lowered by means of a driven pinion, which engage in the teeth 31 of the rods 28.

By moving the rods 28 downward, the membrane 14, those in the middle above the workpiece carrier 12 and the workpiece placed on it (not shown) is lowered when the membrane frame 15 a, 15 b on the frame 20 of the appropriate size rests, which is attached to the surface of the work table 11 is, the space between the workpiece and the diaphragm via the lines 23 evacuated. As a result, the membrane, and with it the blank, is pressed against the workpiece. The membrane presses the edges of the blank against the underside of the Workpiece. Now the workpiece carrier is moved down until its upper surface is lower than the upper surface of the work table. This is communicated to the pole 30 reached, which the workpiece carrier 12 with a pressure medium-operated cylinder 26 connects, which can be operated by means of a switch 27.

The method according to the invention works as quickly as possible is, also solidified thermoplastic materials, for example foam rubber, as Use the baseplate and finish the enrobing process before the thermoplastic Material melts. In this case, of course, pressure adhesive may be used Glue can be used.

Claims (11)

Claims: 1. Vacuum deep drawing process for covering upholstered Workpieces with a coating fabric in which the cover fabric is below the top pressure of the atmosphere against vacuum pressed against the surface of the workpiece and is glued to this with the edges, d a characterized by the fact that the Cut the covering material to size before laying it on and open the blank (18) loosely the workpiece (16, 17 a, 17 b, 18) is placed and the space surrounding the workpiece, which is to form the vacuum chamber, reuse with a piece that has been separated from the blank airtight membrane (14) veer closes. 2. The method according to claim 1, characterized in that the Workpiece (16, 17a, 17b, 18) in a known manner on a workpiece carrier (12 or 45), which is kielner than the lower surface of the workpiece, and that the membrane (14) and the blank (18) over the free lower edge of the workpiece pulls. 3. The method according to claim 1 or 2, characterized in that one on the with the middle part of the blank (18) to be covered surface of the Workpiece (16, 17 a, 17 b, 18) and / or on the edge areas of the lower surface of the workpiece, in which the edges of the blank (18) are glued to the workpiece should be, exerts a mechanical pressure in addition to atmospheric pressure. 4. The method according to any one of claims 1 to 3, characterized in that that the membrane (14) with known weaving of heat-adhesive adhesive heated for the coating process. 5. The method according to claim 4, characterized in that the Membrane (14) heated to about 65 to 1500 C. 6. Device for performing the vacuum forming process according to Claim 1 with a serving for receiving the workpiece on a workpiece carrier, can be closed and evacuated on the side facing away from the workpiece carrier Chamber, characterized in that the closure of the chamber is a part of the device provided airtight, elastically deformable membrane (14), wherein a blank (18) of the covering material with the chamber open between the workpiece (16, 17 a, 17 b, 18) and membrane (14) can be inserted. 7. Apparatus according to claim 6, characterized in that the membrane (14) is heatable. 8. Apparatus according to claim 6 or 7, characterized in that the work table (11) of the device can be heated and that a through the work table (11) guided, on this lowerable carrier (45) is provided, which is to be supported of the workpiece (16, 17 a, 17 b, 18) is used. 9. Apparatus according to claim 6 or 7, characterized in that in the direction of the envelope of the blank (18) around the lower edge of the workpiece (16, 17 a, 17 b, 18) movable pressing devices (41, 41 a, 41 b) for pressing the edges of the blank (18) to be glued to the underside of the workpiece are provided. 10. Apparatus according to claim 9, characterized in that the Pressure devices (41, 41a, 41b) are pressure medium operated 11. Device according to one of claims 6 to 10, characterized in that one against the top of the workpiece (16, 17 a, 17 b, 18) pressable mechanical pressing device (36 to 38) is provided. Publications considered: German Auslegeschrift No.1077962.