Spacer tube

A tubular hollow profile, particularly a spacer tube for the production of spacer frames for insulated glazing, has a profile wall. The profile wall is configured to be double-walled and has an outer wall made of metal, particularly stainless steel or aluminum, and an inner wall made of plastic, which are connected with one another, preferably in firm, i.e. non-displaceable manner. A device and a method for production of the hollow profile are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin-walled, tubular hollow profile, particularly a spacer tube for the production of spacer frames of insulated glazing, as well as to a method and a device for its production.

2. The Prior Art

Conventional insulated glazing has at least two panes of glass disposed parallel to and spaced apart from one another, between which a pane interstice having a defined width is provided. In order to permanently guarantee this predefined pane interstice, a circumferential space holder frame is provided between the two glass panes, which frame connects the two glass panes with one another in the region of their outer pane edges. In this connection, the spacer frame consists of a thin-walled spacer tube having an essentially flat rectangular cross-section, which was bent accordingly to form the spacer frame. Alternatively, the spacer frame consists of multiple individual spacer tubes, which are set onto one another via corner connectors.

Such spacer tubes are hollow profiles made of aluminum, for example, which are produced for example, by means of bending by rollers and subsequent welding of the abutting longitudinal edges of the aluminum strip. These spacer tubes have a wall thickness of 0.3 mm to 0.6 mm. Because of the good heat conductivity of aluminum, however, these spacer tubes made of aluminum have the disadvantage that the region of the outer pane edges, i.e. the pane border region, cools greatly at low outside temperatures. As a result, valuable heat energy is lost. If the temperature furthermore drops to below the dew point in this region, condensate forms, and this condensate can damage the frame construction, particularly in the case of wooden windows.

In order to reduce these effects, more and more spacer tubes made of materials that have clearly lesser heat conductivity have been in use since approximately the mid-1990s, and particularly within the course of the energy savings regulations (EnEV) that went into effect in 2002. In this connection, the term “warm edge” was coined. This term is used for the region of an insulated glazing in which the outer pane edges are connected with one another by means of the spacer tubes, whereby the spacer tubes consist of a material having low heat conductivity.

For example, such spacer tubes consist of stainless steel and have a wall thickness of 0.15 mm to 0.2 mm. These stainless steel spacer tubes are also produced from a stainless steel strip, by means of bending by rollers and subsequent welding of the abutting longitudinal edges of the strip. The spacer tubes made of stainless steel are characterized in that they can be easily processed further, particularly by machine. The spacer tubes can be cut to the correct length and bent to form the spacer frames, in simple manner. The material costs of stainless steel in particular, however, have increased tremendously in recent years.

Furthermore, spacer tubes made of plastic exist, which are produced by means of extrusion. Spacer tubes made of polymer materials having low heat conductivity values have a lower heat passage coefficient in comparison with spacer tubes made of stainless steel. Although such spacer tubes can be produced more cost-advantageously, further processing, particularly bending to form the spacer frames, is difficult. Furthermore, plastic is not ultra-violet (UV) ray resistant, tends to age, and is not completely diffusion-tight. For this reason, it is known to cover the backs of the spacer tubes with a metallic foil. The foil acts as a diffusion barrier. The other stated disadvantages of the spacer tubes made of plastic, however, are not eliminated with this cover.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a tubular, thin-walled hollow profile, particularly a spacer tube for the production of spacer frames of insulated glazing, having a low heat passage value, which can be produced in simple and cost-advantageous manner, and can easily be processed further.

Another object of the invention is to provide a device and a production method for simple and cost-advantageous production of such a hollow profile.

In one aspect, these and other objects are achieved by a tubular hollow profile, particularly a spacer tube for the production of spacer frames for insulated glazing having a profile wall configured to be double-walled and having an outer wall made of metal, particularly stainless steel or aluminum, and an inner wall made of plastic, which are connected with one another, preferably in firm, i.e. non-displaceable manner.

In another aspect, a device is provided according to the invention for production, particularly continuous production, of a tubular hollow profile, particularly of a hollow profile according to the first aspect of the invention above.

The device has, expediently, a metal strip cutting device for cutting a metal band, particularly a stainless steel band or an aluminum band, into multiple longitudinal metal strips that are parallel to one another, particularly stainless steel strips or aluminum strips.

The device further includes, expediently, a plastic strip cutting device for cutting a plastic band into multiple longitudinal plastic strips that are parallel to one another.

The device also includes a gluing device for gluing the metal strip to the plastic strip to form a profile wall strip having two lateral longitudinal edges, and, expediently, a notching or stamping device for introducing longitudinal grooves into a plastic strip top side of the plastic strip that faces away from the metal strip.

The device also includes a device for bending by rollers for deforming the profile wall strip to form a longitudinally slit endless hollow profile whose regions that have the longitudinal edges abut one another, and a welding device for producing a longitudinal weld seam by means of welding the two regions that have the longitudinal edges to one another.

The device also includes, expediently, a calibration device for calibrating the cross-sectional shape of the endless hollow profile, and a cutting device for cutting the endless hollow profile into hollow profiles having a predetermined length.

In a third aspect, a method is provided according to the invention for production, particularly continuous production, of a hollow profile according to the first aspect of the invention above, preferably using a device according to the second aspect of the invention above.

In accordance with the method, expediently, a metal band, particularly a stainless steel band or an aluminum band, is cut into multiple longitudinal metal strips that are parallel to one another, particularly longitudinal stainless steel strips or longitudinal aluminum strips.

Also, in accordance with the method, expediently, a plastic band is cut into the multiple longitudinal plastic strips that are parallel to one another, and the metal strip is glued to the plastic strip to form a profile wall strip having two lateral longitudinal edges.

Expediently, longitudinal grooves are introduced into a plastic strip top side of the plastic strip that faces away from the metal strip, and the profile wall strip is subjected to rolling deformation to form a longitudinally slit endless hollow profile whose two regions that have the longitudinal edges abut one another, whereby the profile wall strip is bent in such a way that the metal strip forms an outer wall and the plastic strip forms an inner wall of the endless hollow profile.

A longitudinal weld seam is produced by means of welding the two regions that have the longitudinal edges to one another. Expediently, the endless hollow profile is calibrated to its final cross-sectional shape, and cut into hollow profiles having a predetermined length.

Advantageous further aspects of the invention are discussed below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now in detail to the drawings and in particularFIGS. 1 and 2, the thin-walled hollow profile1according to the invention is shown. Hollow profile1has a profile wall2having an outer profile surface3and an inner profile surface4, whereby inner profile surface4encloses, i.e. establishes a profile interior5. According to the invention, hollow profile1is furthermore configured to be double-walled, in other words profile wall2has an outer wall6and an inner wall7, which are connected with one another, preferably in firm, i.e. non-displaceable manner. In this connection, outer wall6consists of metal, particularly stainless steel or aluminum, and inner wall7consists of plastic. Furthermore, outer wall6has a wall thickness of preferably 0.04 mm to 0.1 mm, preferably 0.05 mm to 0.08 mm. Inner wall7has a wall thickness of preferably 0.15 mm to 0.5 mm, preferably 0.3 mm. Furthermore, hollow profile1has a longitudinal expanse in the direction of a longitudinal profile axis8.

In this connection, the material of inner wall7is preferably a degradable, i.e. compostable plastic, which expediently consists of a renewable resource. Furthermore, it is practical if the plastic is suitable for being treated with ultrasound, particularly being stamped, i.e. notched by means of ultrasound, and if the plastic is suitable for being injection-molded and extruded. In particular, the plastic has biopolymers, preferably polyhydroxyalkanoates and/or polycaprolactone and/or polyester and/or lignin, and/or lignocellulose and/or natural resins and/or natural fatty acids and/or natural waxes, i.e. consists of these substances. It is practical if the melting point of the plastic lies at 100-170° C., preferably 120-150° C. Furthermore, the plastic preferably has the following material properties (alternatively or cumulatively).

Hollow profile1according to the invention is produced from a double-layer profile wall strip29(FIG. 3) by means of rolling deformation; this strip has a metal strip10, particularly a stainless steel strip or aluminum strip, coated with a plastic strip9, all of which will be discussed in greater detail below. As a result, hollow profile1has a longitudinal weld seam11that extends parallel to the longitudinal profile axis8. The regions of two longitudinal edges12of metal strip10that are adjacent to one another after bending by rollers are welded to one another by means of longitudinal weld seam11. In particular, outer wall6is bent around into the profile interior5in the region of the two longitudinal edges12, so that two flange cheeks13are formed, whereby the two flange cheeks13lie against one another and are connected with one another by means of longitudinal weld seam11. Longitudinal weld seam11is therefore preferably a beaded seam, and the weld connection is configured as a flange weld connection. Alternatively, longitudinal weld seam11can also be configured as an overlapping weld or as a butt weld.

Furthermore, hollow profile1is preferably a spacer tube14from which spacer frames for insulated glazing can be produced. For this purpose, spacer tube14has an essentially rectangular cross-section, whereby profile wall2has a ceiling wall15that is preferably planar, a floor wall16that expediently lies parallel to the former and is preferably planar, and two side walls17that are preferably planar. Side walls17are preferably disposed perpendicular to ceiling wall15and to floor wall16. Furthermore, it is practical if a transition wall18is provided between a side wall17and the floor wall16, in each instance. Side walls17and ceiling wall15preferably make a direct transition into one another. Furthermore, the walls15;16;17;18that lie adjacent to one another are disposed angled relative to one another, in each instance, and make a transition into one another by way of a bent edge, i.e. corner edge33, in each instance. In this connection, the two transition walls18are preferably configured as a type of bevel, in other words the corner region between a side wall17and the floor wall16, in each instance, is flattened by means of transition walls18.

Furthermore, it is practical if the expanse of the spacer tube14is greater in a width direction19athat lies perpendicular to longitudinal axis8than in a height direction19bthat is perpendicular to the former and to the longitudinal axis8. In this connection, ceiling wall15and floor wall16extend parallel to longitudinal axis8and to width direction19a, and side walls17extend parallel to longitudinal axis8and to height direction19b.

In the installed state of spacer tube14in the insulated glazing, ceiling wall15is disposed facing a pane interstice formed between two panes, and the two side walls17lie against the glass panes and are connected with them in known manner, to be moisture-tight and air-tight, by means of a suitable adhesive. Floor wall16consequently faces away from the pane interstice. As a consequence, longitudinal weld seam11, in order not to be visible in the installed state of spacer tube14, is preferably not disposed in the region of ceiling wall15. Preferably, longitudinal weld seam11is disposed in the region of one of the side walls17.

Furthermore, preferably multiple known passage recesses, i.e. perforation openings20, preferably in the form of slits that pass through ceiling wall15, are made, particularly punched, into ceiling wall15, whereby perforation openings20create a connection, in terms of flow technology, between the profile interior5and the pane interstice. Perforation openings20can also be configured, at least in part, as oblong holes that extend parallel to width direction19a(not shown).

FIG. 6shows a spacer frame40for insulated glazing which is formed by bending the spacer tube14that is described herein. The spacer frame40includes a separating cut41and a connector42.

In the following, the production of hollow profile1according to the invention will now be explained in greater detail, particularly using the production of spacer tube14, by means of the device according to the invention.

As already explained above, production of hollow profile1takes place by means of bending by rollers and longitudinal welding. For this purpose, first a relatively broad metal band, particularly a stainless steel band or an aluminum band, is cut into multiple longitudinal metal strips10that lie parallel to one another, particularly longitudinal stainless steel strips or longitudinal aluminum strips, and these are preferably wound up onto a reel. Alternatively, metal strips10are already present wound up onto a reel.

It is practical if, at the same time with the production of metal strips10, a relatively broad plastic band is cut into multiple plastic strips9that lie parallel to one another, in a plastic strip cutting device, and these are preferably wound up onto a reel. Alternatively, plastic strips9are also already present wound up onto a reel. In particular, the plastic band or the plastic strips9are produced by means of extrusion.

Subsequently, the two strips9;10are glued to one another in a gluing device, expediently using a melt adhesive23. For this purpose, the gluing device has an adhesive application device21(FIG. 4) that has a heated melting tank22for accommodating liquid melt adhesive23, an application roller24that can be driven about a horizontal axis of rotation, a counter-pressure roller25that can also be driven about a horizontal axis of rotation, but in the opposite direction of rotation, and, expediently, two strippers26,27, namely a metering stripper26and a closing stripper27. In this connection, application roller24is disposed below melting tank22, so that it closes melting tank22off toward the bottom and melt adhesive23is distributed on the region of a mantle surface24aof application roller24that faces melting tank22.

The two strippers26;27are disposed adjacent to application roller24, spaced apart from application roller24by a ring-shaped gap. In this connection, the distance of metering stripper26from application roller24determines the thickness of the adhesive layer that application roller24has on its mantle surface24aafter it passes metering stripper26, and thus the thickness of the adhesive layer to be applied. Closing stripper27prevents adhesive from exiting when roller24is at rest.

To apply melt adhesive23to a metal strip10, metal strip10is guided through between the two rollers24;25in a transport direction28. In this connection, melt adhesive23picked up by application roller24from melting tank22is applied to a metal strip top side10aof metal strip10. After adhesive23has been applied, plastic strip9is laid onto metal strip top side10awith a plastic strip underside9band pressed onto it, so that the two strips9;10are glued to one another over their full area and form profile wall strip29. In particular, in this connection, plastic strip9is laid onto metal strip10centered with reference to the expanse of profile wall strip29in a strip width direction30. Furthermore, the expanse of plastic strip9in the strip width direction30is less than the expanse of metal strip10in the strip width direction30, so that an edge region31of the metal strip is uncoated on both sides, in each instance (FIG. 3). In this connection, joining of plastic strip9and metal strip10preferably takes place continuously, by means of transporting the metal strip10in its longitudinal direction, particularly horizontally, drawing plastic strip9from the reel, laying plastic strip9onto metal strip10, and pressing the two strips9;10against one another by means of rollers.

In this connection, the melt adhesive23used is preferably a hot-melt adhesive, particularly a single-component polyurethane adhesive, whose basic substances are, in particular, polyurethane prepolymers having isocyanate groups. It is practical if the melt adhesive23used has a density of 1.15 to 1.25 g/cm3. Furthermore, the melt adhesive23preferably has a (dynamic) viscosity of 18,000 to 34,000 MPas. The melt adhesive23is furthermore preferably insoluble in water.

It is practical if the profile wall strip29produced by means of gluing is passed to a drying device, particularly a drying segment, in which the melt adhesive23can dry and harden.

Subsequently, profile wall strip29is passed to a notching or stamping device of the device according to the invention, by means of which longitudinal grooves or longitudinal beads or notches32that extend longitudinally are made, particularly stamped, in a plastic strip top side9athat faces away from metal strip10. Longitudinal grooves32extend parallel to a longitudinal strip direction36and expediently have a V-shaped cross-section. Longitudinal grooves32are made where the bent edges33of the subsequent hollow profile1lie. In this connection, it is practical if introduction of longitudinal grooves32takes place by heating the plastic material by means of ultrasound, and stamping the preferably wedge-shaped longitudinal grooves32into the heated material. For this purpose, the notching device has an ultrasound generation device, a sonotrode for passing the vibrations that are generated to the plastic strip9to be stamped, and an anvil roller that can be driven about a horizontal axis of rotation. The anvil roller is disposed below the sonotrode, and disposed spaced apart from the latter by a defined gap. The sonotrode has a horizontal stamping surface that faces the anvil roller, which has multiple bulges that are disposed adjacent to one another and stand away from the stamping surface, for making longitudinal grooves32. The bulges extend parallel to a transport direction, expediently a horizontal direction, and are disposed adjacent to one another perpendicular to the transport direction. In this connection, the placement and the number of bulges depends on the placement and the number of bent edges33. For stamping, profile wall strip29is guided through between the stamping surface and the anvil roller, with the plastic top side9afacing the sonotrode, in the transport direction, which is parallel to the longitudinal strip direction36. In this connection, the plastic material is heated by means of the sonotrode, and longitudinal grooves32are stamped into plastic strip top side9aby means of the bulges, with the application of pressure.

According to another embodiment of the invention, a rotating sonotrode that can be driven about a horizontal axis of rotation, in the direction of rotation opposite to the anvil roller, is used in place of the fixed sonotrode, whereby the speeds of rotation are synchronized. In this case, the sonotrode has ring-shaped bulges on its sonotrode mantle surface that project from that surface, which serve to introduce longitudinal grooves32. For this purpose, the bulges extend circumferentially in the circumference direction of the sonotrode roller.

After introduction of longitudinal grooves32, it is practical if the passage holes20are introduced into profile wall strip29, in known manner, in a punching device. For this purpose, profile wall strip29is guided between two punching rollers that are driven about a horizontal axis, in each instance, and spaced vertically apart from one another, in a transport direction that is preferably horizontal, parallel to the longitudinal strip direction36. The punching rollers have appropriate punching means. In particular, the one punching roller has teeth that project from its mantle surface, and the other punching roller has recesses that correspond to them.

After passage holes20have been made, profile wall strip29is continuously deformed in a device for bending by rollers, i.e. rolling deformation device of the device according to the invention, by means of rolling deformation, to form a longitudinally slit endless hollow profile38, in such a manner that its cross-sectional shape preferably already corresponds to the cross-sectional shape desired later. In particular, first the two free edge regions31are bent around to form the flange cheeks13, and subsequently, profile wall strip29is bent to form the longitudinally slit endless hollow profile38, in such a manner that the two flange cheeks13abut one another. In particular, profile wall strip29is bent, i.e. bent around at longitudinal grooves32. Profile wall strip29is therefore bent about axes that lie parallel to the longitudinal strip direction36, i.e. the subsequent longitudinal axis8.

Furthermore, profile wall strip29is deformed in such a manner that metal strip10lies on the outside, in particular, metal strip underside10bforms the outer profile surface3and it is practical if the two flange cheeks13are disposed at the top. To implement an overlapping weld seam or a butt weld, appropriate preparation takes place as required.

Rolling deformation takes place in known manner, using corresponding rolling deformation tools, particularly using multiple pairs of deformation rollers (not shown) that are disposed one behind the other in a transport direction that lies parallel to the longitudinal strip direction36, preferably a horizontal direction, in which the profile wall strips29are transported.

In this connection, profile wall strip29is guided between the two deformation rollers of a pair of deformation rollers, in each instance. In this connection, the one deformation roller has a circumference surface curved to be concave, and the other deformation roller has a circumference surface curved to be convex, whereby the circumference surfaces are coordinated with one another, and the curvature increases from one pair of deformation rollers to another, in such a way that the profile wall strip29is gradually bent into the longitudinally slit endless hollow profile38.

In a welding device37of the device according to the invention, which follows the rolling deformation device, the two flange cheeks13that abut one another are welded to one another by producing longitudinal weld seam11, particularly continuously. Welding takes place by means of laser welding, for example. For this purpose, welding device37has a laser beam generation device and means for deflecting the laser beam34and directing the laser beam34onto the flange cheeks13(FIG. 5). In particular, laser beam34is oriented in such a way that it encloses an angle α of 8° to 25°, preferably 10° to 15°, with the horizontal transport direction35in which the endless hollow profile38is being conveyed, i.e. with the surface to be welded. This arrangement brings about the result that laser beam34impacts the material to be welded in the shape of an elliptical point, thereby causing a longer melt bath to be formed and the energy to be better introduced into the material. This feature is a significant advantage particularly in the case of the thin wall thickness of outer wall6, and guarantees secure welding.

Welding device37is followed by a known calibration device of the device according to the invention, in which the welded endless hollow profile38is calibrated to its final cross-sectional shape. For this purpose, it is practical if the calibration device has multiple calibration rollers, in known manner.

Furthermore, the device according to the invention also has a device for cutting endless hollow profile38into hollow profiles1, particularly spacer tubes14having a predetermined length, which follows the calibration device. The cutting device is, for example, a flying saw, in other words a saw that moves along with endless hollow profile38in the transport direction while cutting.

Hollow profile1according to the invention has a very low linear heat passage coefficient because of the plastic inner wall7and the low wall thickness of the metal outer wall6that is possible as a result. In particular, the linear heat passage coefficient lies at 0.03 to 0.07 W/mK, preferably 0.035 to 0.05 W/mK. The low wall thickness of metal outer wall6furthermore has the advantage that tremendous material costs are saved in comparison with purely metal hollow profiles. Providing such low wall thickness values for the metal outer wall6is particularly possible because plastic inner wall7supports and stabilizes metal outer wall6, so that in particular, flange cheeks13can be pressed against one another with sufficient press-down forces even at such low wall thickness values, and reliable welding is achieved.

Furthermore, hollow profile1according to the invention can be processed further in excellent manner. In particular, spacer tubes14that consist of hollow profile1can be bent to form spacer frames, in conventional manner and on conventional machines.

Because of the metallic outer profile surface3, the hollow profile1according to the invention can also be painted without problems. Furthermore, the outer profile surface3is UV-resistant. The spacer tubes14according to the invention that have the stainless steel outer wall can also be used in the renovation or expansion of buildings in which conventional spacer tubes made of stainless steel or having a metallically shiny surface were used until now, because of this stainless steel outer surface.

Furthermore, the special selection of the hot-melt adhesive23and the plastic material is particularly advantageous, creating a preferably firm, i.e. non-displaceable, permanent bond between plastic strip9and metal strip10, i.e. of inner wall7and outer wall6.

It is furthermore advantageous that production of hollow profile1according to the invention can take place on conventional machines, to the greatest possible extent. Only the steps of cutting and gluing plastic strip9onto metal strip10and stamping of longitudinal grooves32are added. Stamping of longitudinal grooves32in turn has the advantage that the recovery forces after rolling deformation are small enough to be ignored, since no plastic material is displaced during rolling deformation.

Furthermore, as already explained above, it also lies within the scope of the invention to coat the hollow profile with paint on the outside. For this purpose, a metal band that is relatively broad, at first, for example, which is expediently wound up onto a reel, is pulled off this reel, passed through a paint coating device, and continuously coated with paint, on one side, in this device. Coating takes place by means of application of the paint by means of a known roller printing device having an application roller, for example. After subsequent drying of the paint in a dryer device through which the coated metal band is expediently guided continuously, the coated metal band is cut into multiple longitudinal strips10that are parallel to one another. It is practical if this also takes place continuously, in a cutting device.

Furthermore, the production method as a whole or the individual production steps can take place continuously, in other words in a single production line, or also non-continuously, in individual devices separated from one another. In the case of the continuous method; the individual devices are disposed one behind the other, in accordance with the method sequence.

Furthermore, introduction of the longitudinal grooves into the plastic strip9can also take place by means of a profiled and heated profile disk or another type of material displacement under the influence of heat.

Furthermore, it is also possible to provide the plastic strip with adhesive23in place of metal strip10. In particular, in this case, adhesive23is applied to plastic strip underside9b, whereby plastic strip9is guided through between the two rollers24;25with plastic strip underside9bfacing application roller24. Subsequently, the two strips are glued to one another as described above.

Of course, the hollow profile1according to the invention is not restricted to use as a spacer tube14, but rather can also be used as a hand rail and/or railing tube and/or water pipe and/or supporting tubular construction and/or substitution for the light-construction method, for example.