EP0146883B1 - Corner forming method for spacer frames of edge-sealed insulating glazing units - Google Patents

Abstract

In a process of manufacturing a spacer frame for a perimeter-bonded insulating glass pane, a metal tubular bar is filled with a granular desiccant and is subsequently bent in each corner-forming portion about an axis which is at right angles to two parallel cheeks of the bar. The two cheeks are drilled through in each of said corner-forming portions to form two bores and a small quantity of the granular desiccant is removed from each of said corner-forming portions through at least one of said bores therein before said corner-forming portion is bent.

Description

The invention relates to a method for forming the corners of spacer frames for edge-glued insulating glass panes by bending metallic hollow profile bars, which are already filled with a desiccant, about an axis running at right angles to the two mutually parallel flanks of the hollow profile bar.

The invention further relates to a device for removing granular desiccants according to the preamble of claim 13. In the case of edge-glued insulating glass, two individual glass panes are glued to one another by a spacer frame inserted between them and kept at a distance. The spacer frames usually consist of metallic hollow profile bars, usually made of stainless steel or aluminum, which are filled with a desiccant, which serves to keep the residual moisture enclosed in the insulating glass pane so low that the insulating glass panes cannot fog up when the temperature drops inside. The finished spacer frames filled with the desiccant are coated on both sides with a permanent adhesive and sealant (usually a polyisobutylene) before installation in an insulating glass pane, which adheres to two separate glass panes after inserting the spacer frame and thereby the solid Causes bond within the insulating glass pane.

Granular desiccants, which are easy to pour, are mostly used to fill the hollow spacer frames. Molecular sieves are mostly used as drying agents; another option is to use silica gel.

The most common way of producing spacer frames is based on straight profile sections, which are initially filled with the desiccant and at their ends with a stopper, e.g. B. made of foam rubber, ver. closed and then connected by means of corner angles, which are inserted into the ends of the profile sections, to form a closed frame. However, using corner brackets has a number of disadvantages: numerous steps are required to assemble the spacer frames, the corner connections are often quite unstable and require a particularly careful coating with the adhesive and sealant to be applied to the flanks of the spacer frame.

In this patent application, the flanks are always the mutually parallel walls of the hollow profile bars or the spacer frames formed from them, which rest in the finished insulating glass pane with the two individual panes thereof - with the adhesive being interposed.

It has also already been proposed to produce the spacer frames from a single hollow profile bar by bending the corners, so that there is only a single joint in each spacer frame and has to be closed by a connecting part, the joint both at one of the frame corners and in the area can lie between two adjacent corners.

Now the bending of hollow profile bars with small bending radii is not quite easy, in the present case it is made even more difficult by the fact that the hollow profile bars are filled with a granular, almost incompressible desiccant. Although it has already been proposed to fill the spacer frame with the desiccant only after the corners have been bent, this procedure is quite complex since, for this purpose, all four legs of the spacer frame have to be opened, individually filled and then sealed again.

• An den Ecken der Isolierglasscheiben erhält man eine sehr viel tiefere Randfuge als über den geradlinigen Abschnitten des Abstandhalterrahmens, und diese tieferen Randfugenbereiche lassen sich nur schwer mit einem der üblichen zäh-pastösen Dichtungsmittel füllen, mit denen randverklebte Isolierglasscheiben üblicherweise versiegelt werden. Ausserdem sind die viertelkreisförmig gebogenen Rahmenecken gut sichtbar, wenn die lsolierglasscheiben in rechteckige Fensterrahmen ohne abgerundete Ecken eingebaut werden, es sei denn, man erhöht die Falzbreite der Fensterrahmen über das übliche Maß hinaus so weit, bis sie auch die viertelkreisförmig gebogenen Abstandhalterrahmenecken verdeckt.

If you want to bend hollow section bars that are already filled with desiccant, you have to struggle with the problem that the desiccant is increasingly compressed in the corner areas as the bending process progresses, which often leads to the hollow section being torn open due to the incompressibility of the desiccant. To avoid this, it has already been proposed (Austrian patent application No. 7018/78) to bend the frame corners in a quarter circle with a larger bending radius. Although this reduces the risk of tearing open the hollow profile at the corners of the frame, it does have other disadvantages:

• At the corners of the insulating glass panes, a much deeper edge joint is obtained than above the straight-line sections of the spacer frame, and these deeper edge joint areas are difficult to fill with one of the usual tough-pasty sealants with which edge-bonded insulating glass panes are usually sealed. In addition, the quarter-circle curved frame corners are clearly visible if the insulating glass panes are installed in rectangular window frames without rounded corners, unless the rebate width of the window frames is increased beyond the usual size until it also covers the quarter-circle curved spacer frame corners.

Furthermore, it has already been proposed to slit the hollow profile bars filled with the desiccant with a milling tool before bending in the interior of the later frame corners. The position of the slots exactly marks the apex of the corners and makes the bending process a little easier, but does not prevent the hollow profile bars from tearing on the outside when working with small bending radii (EP-A-0 003 715).

In addition, it has already been proposed that the hollow be filled with the desiccant Do not just cut profile bars at the point where the apex of a corner later lies, but also blow out a smaller part of the desiccant from the hollow profile bar through the interface. This counteracts the risk of tearing open the hollow profile bars during bending.

However, the latter two methods have the disadvantage that the shape, the width and the position of the slots must be carefully selected so that they close automatically during the bending process to such an extent that further drying agent leakage is prevented after the bending. This cannot be guaranteed in every case. In addition, the incisions in the corner region of the spacer frames represent a weakening, which makes the spacer frames, which are not very stable anyway, even more unstable.

The invention has for its object to provide a simple and inexpensive method for forming the corners of spacer frames, by means of which the spacer frames can be bent from hollow profile bars already filled with desiccant with small bending radii, without the frames tearing open at the corners and without the hollow profile bars before bending the corners on the inside of a later corner would have to be cut open, so that the weakening by such a cut is not necessary. A device for removing granular desiccant is also to be created.

This object is achieved by a method with the features specified in claim 1. Furthermore, the object is achieved by a device with the features described in claim 13. Advantageous developments of the invention are the subject of the dependent claims.

According to the invention, the hollow profile bars filled with a desiccant are not cut open on the inside of the later spacer frame over its width, but are drilled out on the two flanks where a corner is provided. These holes make it possible to remove a small amount of the desiccant filled into the hollow section rod from the area intended for the corner. How large this quantity has to be depends on how much the volume of the hollow profile rod is reduced when bending in the area of a corner. This reduction in volume can easily be determined experimentally for different hollow profile bars.

After removing the intended amount of desiccant from the area intended for the corner, the hollow section rod is bent to form a corner. As a result of the bending process, the holes in the flanks close automatically, as a compression occurs on the flanks during bending. There is also an expansion of the metallic profile wall on the outside of the respective corner, but this expansion does not extend to the flanks, because the flanks do not usually extend directly to the later outside of the spacer frame, but through inclined surfaces with which the outer wall of the Spacer frame forming profile wall are connected.

By bending the corners, the holes in the flanks are closed so far that a granular desiccant can no longer escape. Any remaining openings are completely closed by the subsequent coating of the flanks of the spacer frame with an adhesive and sealing compound. This is a major advantage of the invention.

The result is a spacer frame which is bent from one piece and is absolutely tight at all of its curved corners and is undamaged on the inside and outside in the corner area. Such a frame has optimal stability.

The bores in the two flanks of the hollow profile rod are preferably mirror images of the central plane of the hollow profile rod parallel to the flanks, in particular precisely on the bisector of each corner. Through openings arranged in this way, the desiccant can be removed most easily from the corner region and the bending process itself is also promoted by such an arrangement of the openings because the flanks which are usually raised when bending hollow profile bars are due to the material removed by the boring raise less from the flanks at this point than in the prior art. Nevertheless, when carrying out the method according to the invention, it is advisable to clamp the flanks of the hollow profile rod to be bent at the bending point between a pair of clamping jaws or between a hold-down device and an abutment arranged parallel to the hold-down device, in order to raise the flanks in a manner known per se prevent. Due to the installation of the spacer frames in an insulating glass pane, the flanks could of course not be tolerated.

In principle, the flanks of the hollow profile bar could be drilled out with a drill which is placed on one flank from the outside, drilled through it and then hits the second flank through the interior of the hollow profile bar. Preferably, however, the flanks of the hollow profile rod are both drilled from the outside inwards, expediently by simultaneously feeding two opposing drills onto the two flanks. This has the advantage that the burr generated by the drilling is on the inside on both flanks and does not interfere with the later installation of the spacer frame in an insulating glass pane. Furthermore, two further disadvantages are avoided, which occur when using only one drill which is passed through the interior of a hollow profile rod: this one drill would need one to behave long feed path and could run on a web lying inside the hollow profile in some profile shapes.

Since the desiccant to be removed from the area of the later corner is to be removed through the holes, the diameter of the holes depends on the grain size of the desiccant used. The holes must of course be at least large enough that the largest grain of desiccant can still pass through. In the currently customary granulations of the desiccants used for filling into spacer frames, it is expedient to use bores with a diameter between 2 mm and 3 mm, preferably between 2.6 mm and 2.9 mm.

The desiccant is preferably removed by applying compressed air to one of the bores after the flanks of the hollow profile rod have been drilled open, thereby blowing out desiccant from the opposite bore. Furthermore, it is preferably provided that in addition to blowing compressed air into this, a bore is directed to the opposite bore compressed air pulses. In this way, it is possible to remove a grain of the desiccant, which may have become jammed in the bore from which the desiccant is to be blown out, from the bore, so that at most a very brief blockage of the bore can occur. In order to increase the effect of such compressed air pulses, they are preferably directed onto the bore alternately from different directions. Removing the desiccant is also made easier if you alternately pressurize the two holes; A change of blowing direction every 0.1 s to 0.2 is particularly effective.

In principle, the desiccant could be blown out of the hollow profile rod on both sides through the holes. Preferably, however, it is only blown out to one of the holes; it is then possible to control the amount of desiccant removed in a relatively simple manner (see pages 16 and 17). Escape of desiccant from one of the holes can be done, for. B. simply prevent that a blow nozzle with a correspondingly small mouth width is placed directly on this one bore. On top of this, this has the advantage that the compressed air can penetrate directly into the hollow profile rod from this one blowing nozzle. The nozzle (s) arranged on the other side of the hollow profile rod can easily be at a distance from the bore located there, since the compressed air pulses emanating from them do not penetrate deeply into the hollow profile rod, but are only intended to clear jammed desiccant particles.

In order for the bend to take place in a defined form and at a precisely defined point, it is preferred to slightly press in that wall of the hollow profile bar which is inside after the bending, before bending along the line where the vertex of the corner is after the bending, without cutting them open.

In addition, it is preferred to carry out at least the removal of the desiccant from the later corner area with a horizontally lying hollow profile rod running vertically with its flanks, and from this position to also carry out the bending about a horizontal axis. With such an arrangement, it can be assumed that desiccant only slips to a small extent in the free space created in the interior of the hollow profile rod, so that there is free space essentially over the entire profile width during the bending process. In particular, it is advisable to arrange the hollow profile rod in such a way that, at least when the desiccant is removed, it faces upward with that wall which is inside after the bending. Desiccant sliding into the area between the holes then leaves at least that part of this area free in which the greatest compression occurs during bending.

How much the hollow profile rod is compressed on its inside and stretched on the outside can be influenced to a certain extent by the choice of the position of the bending axis. The bending axis is preferably placed in such a way that it passes through the two flanks and intersects the bisector of the corner.

But it could also be on the outside of the hollow profile rod.

In order to be able to blow out a precisely defined amount of desiccant, the desiccant is blown into a collecting mold, which is placed on a flank of the frame profile. This collecting form has the shape of an open cylinder at the head end with a piston arranged displaceably therein. This cylinder is placed with its head end on one of the bores and its piston, depending on the hollow profile rod to be bent, is brought into such a position that the size of the chamber volume between the front of the piston and the flank of the hollow profile rod, on which the cylinder is placed, corresponds exactly to the amount of desiccant to be removed. A blowing nozzle is placed on the opposite hole in the hollow profile rod and the amount of desiccant to be removed is blown into the opposite cylinder by means of this blowing nozzle. The distance between the blowing nozzle and the cylinder can be varied to adapt to hollow profile bars of different widths. After the predetermined amount of desiccant has been blown out of the hollow profile rod, the cylinder is removed from the hollow profile rod and the desiccant accumulated in it is expelled from the head of the cylinder or - after the piston has been withdrawn to behind a lateral outlet opening in the rear part of the cylinder - through it aspirated outlet opening.

The piston is guided with so much play in the cylinder that compressed air can flow along the piston and escape from the cylinder, but not the desiccant that has accumulated in the cylinder, as long as the piston has not been withdrawn so far that it has released the side outlet opening.

The cylinder head preferably also contains at least one, preferably two mutually opposite air outlet nozzles which open into the opening of the cylinder head and are directed obliquely out of the opening of the cylinder head. Such nozzles can be used, preferably alternately, to direct compressed air pulses into that bore in the hollow profile rod on which the cylinder is placed. Grains of desiccant, which may have got stuck in the bore of the hollow profile rod, can be freed again by these compressed air pulses.

• Figur 1 zeigt in Schrägansicht einen Hohlprofilstab, welcher bereits mit einem Trockenmittel gefüllt ist, vor einem Biegevorgang,
• Figur 2 zeigt in Schrägansicht denselben Hohlprofilstab nach dem Biegen einer Ecke, und
• Figur3 zeigt einen waagerechten Schnitt durch den Hohlprofilstab aus Fig. 1 mit einer auf die beiden Flanken aufgesetzten Vorrichtung zum Entfernen von Trockenmittel durch die Bohrungen in den Flanken.

The invention is explained in more detail below with reference to the attached schematic drawings:

• FIG. 1 shows an oblique view of a hollow profile rod, which is already filled with a desiccant, before a bending process,
• Figure 2 shows an oblique view of the same hollow section bar after bending a corner, and
• Figure 3 shows a horizontal section through the hollow profile rod from Fig. 1 with a device placed on the two flanks for removing desiccant through the holes in the flanks.

1 shows a metallic hollow profile rod, consisting of a base 1, of a wall 2 which is parallel to the base but narrower than the base 1 and two side walls which connect the base 1 and the wall 2 opposite the base and are divided into two flanks 3a and 3b parallel to one another and at right angles to the base 1 and two bevels 4a and 4b which lead from the flanks 3a and 3b to the wall 2. The base 1 forms the inside of the later spacer frame and is provided with a perforation 5, through which a granular desiccant filled into the hollow profile rod 6 can absorb and bind moisture from outside the hollow profile rod.

In order to be able to bend a rectangular spacer frame from such a hollow profile bar, which is already filled with the desiccant 6, the two flanks 3a and 3b of the hollow profile bar are drilled transversely at the intended bending point, in a plane which is at right angles to the longitudinal axis of the hollow profile rod and contains line 7, which later marks the vertex of the corner. The bores 8 are best produced simultaneously on both flanks 3a and 3b by twist drills 9 placed on the outside. The burr formed during drilling is then inside in both cases and does not interfere.

After the flanks 3a and 3b have been drilled out, part of the desiccant 6 is removed from the intended corner region through the bores 8. This is expediently done with the hollow profile bar lying down, the narrow wall 2 lying on a horizontal base 10. This has the advantage that slipping of desiccant 6 from the side into the intended corner area is limited and, above all, below the base 1 in the alignment of the bores 8, that is, where the greatest compression takes place during bending Free space remains in the hollow section bar.

After removing the intended amount of desiccant 6, the hollow section rod is pressed in a little at its base 1, waving to the right in the longitudinal direction of the hollow section rod, along the line 7 which, after the corner (FIG. 2) has been bent, marks the apex of the corner . The base can be pressed in along line 7 using a wedge-shaped tool; Make sure that the base 1 is only pressed in but not cut. The hollow profile rod is then bent through 90 °, preferably out of the position shown in FIG. 1, so that even after bending, one leg 11 still lies on the horizontal base 10, while the bent leg 12 projects vertically upward.

The bending itself can be done in a manner known per se; basically suitable bending devices are described in EP-B-1-9703 and in the older German patent application P 32 31 698.4 or in the published Austrian patent application 1354-82. It is advisable to clamp the flanks 3a and 3b in the vicinity of the bores 8 between two clamping jaws with flat clamping surfaces during the bending process, so that otherwise possible flaring up of the flanks is avoided.

The two bores 8 are practically completely closed by the bending process. When further handling with the bent profile bar or later with the finished bent spacer frame, no more desiccant can escape from the holes 8.

Finally, the holes 8 are sealed absolutely tight by coating the flanks 3a and 3b with an adhesive and sealing compound (usually polyisobutylene), which is required at a later point in time, which is required in the production of the insulating glass panes, in order to apply two individual glass panes with the to connect the spacer frame between them firmly.

The method according to the invention thus gives a spacer frame which is absolutely tight in the corner region and is not cut open along the inner apex line 7, so that the frame is mechanically very stable, no loss of desiccant into the interior of an insulating glass pane is possible, and / which in Corner area also has no cracks on the outside, because due to the desiccant removed from the corner area, there is no longer any fear of the profile walls being overstretched.

A device of the type shown in FIG. 1 is used to remove the desiccant from the area of the bores 8 in the hollow profile bar. This device consists on the one hand of a blowing nozzle 20 which covers the bore 8 and is placed on one flank 3a of the hollow profile bar, and on the other hand from a cylinder 21, which is placed with its one open end on the opposite flank 3b of the hollow profile rod and covers the bore 8b located there. The cylinder bore 22 is stepped, in such a way that the diameter of the bore is smaller in the front part of the cylinder than in the rear part of the cylinder. At the transition from the rear part of the bore to the front part of the bore in the cylinder there is a collar surface 23 which forms a stop for a stepped piston 24. The front portion 24a of the piston has a smaller diameter than the rear portion 24b of the piston. With the collar surface 25 formed between the front section 24a and the rear section 24b, the piston strikes the collar surface 23 of the cylinder. With its rear portion 24b, the piston 24 is guided in seals 26 and 27, which are arranged in the rear portion of the cylinder. The front section 24a of the piston plunges into the narrower section of the cylinder bore 22 and its immersion depth determines the size of the cavity in the cylinder head 28 between the piston 24 and the flank 3b of the hollow profile rod. A certain amount of desiccant 6 is blown into this cavity by means of the blowing nozzle 20 from the hollow profile rod. The compressed air flowing in the direction of arrow 29 through the blowing nozzle 20 enters the hollow profile rod through the bore 8 and out of the hollow profile rod through the opposite bore 8b and thereby drives part of the granular desiccant out of the bore 8b into the cylinder head 28. The front section 24a has so much play in the narrower front section 22a of the cylinder bore that the air flows along the piston 24 and can leave the cylinder through a rearward side outlet 30. On the other hand, the play of the front section 24a of the piston in the front section 22a of the cylinder bore is so small that the granular desiccant 6 cannot get along the piston into the outlet 30 as long as the piston with its front section 24a is still in the front section 22a of the cylinder bore plugged. Only when the amount of desiccant determined by the piston position has been removed from the hollow profile rod is the cylinder 21, for example, moved a little way downwards perpendicularly to the plane of the drawing, the piston 24 is pulled back to an end position, which is shown in dashed lines in FIG. 1, and the desiccant in the cylinder head is sucked out through the outlet port 30.

In the cylinder head, two air outlet nozzles 31 are also provided at two diametrically opposite points, which are directed into the opening of the cylinder head 28 and through which compressed air pulses can be directed alternately against the bore 8b during the blowing out of the drying agent 6 from the hollow profile rod in order to separate individual grains of the To get rid of desiccants that may have got stuck there.

Claims (16)

1. A process of shaping the corners of spacer frames for use in insulating glass panes having adhesively joined edges, wherein hollow profiled metal bars previousla filled with a granular desiccant are bent about an axis which is at right angles to the two mutually parallel side walls of the hollow profiled bar,
characterized by the following steps :

a) The two side walls (3a, 3b) of a hollow profiled bar are formed with through bores where the formation of a corner is intended,

b) a small amount of the desiccant (6) which has been filled into the hollow profiled bar is removed from the region that is intended for the corner;

c) the hollow profiled bar is bent.

2. A process according to claim 1, characterized in that the bores (8) in the two side walls (3a, 3b) of the hollow profiled bar are mirror images of each other with respect to that center plane of the hollow profiled bar which is parallel to the side walls (3a, 3b).

3. A process according to claim 1 or 2, characterized in that both side walls (3a, 3b) of the hollow profiled bar are drilled from the outside to the inside.

4. A process according to any of the preceding claims, characterized in that the bores (8) have a diameter between 2 mm and 3 mm, preferably between 2.6 mm and 2.9 mm.

5. A process according to any of the preceding claims, characterized in that the desiccant (6) is removed in that compressed air is blown into one of the bores (8).

6. A process according to claim 5, characterized in that compressed air is blown into one of the bores (8) and compressed air pulses are directed to the opposite bore (8a).

7. A process according to claim 6, characterized in that said compressed air pulses are directed to the bore (8b) from different directions in alternation.

8. A process according to claim 6, characterized in that the two bores (8) are supplied with compressed air in alternation.

9. A process according to any of the preceding claims, characterized in that before the bending operation that wall (1) of the hollow profiled bar which is disposed on the inside after the bending is slightly depressed, but is not cut open, along that line (7) and which the apex of the corner is disposed after the bending.

10. A process according to any of the preceding claims, characterized in that the hollow profiled bar extends horizontally and has vertical side walls (3a, 3b) at least during the removal of the desiccant (6) from the region which will subsequently form the corner and at the beginning of the bending operation performed about a horizontal axis.

11. A process according to claim 10, characterized in that the wall (1) of the hollow profiled bar which is disposed on the inside after the bending operation faces upwardly at least during the removal of the desiccant.

12. A process according to any of the preceding claims, characterized in that the axis about which the bar is bent extends through the two side walls (3a, 3b) and intersects the angle bisector of the respective corner.

13. Apparatus for removing granular desiccant from hollow profiled bars having through bores, for use in a process according to any of the preceding claims, characterized by a blast nozzle (20) in combination with a cylinder (21), which contains a displaceably mounted piston (24) and is disposed opposite to the blast nozzle (20) at a variable distance thereform and is open at the forward end of the cylinder head (28).

14. Apparatus according to claim 13, characterized in that at least one air discharge nozzle (31) is provided in the head of the cylinder (21) and is directed into the opening of the cylinder head (28).

15. Apparatus according to claim 13 or 14, characterized in that a lateral exit opening (30) is provided in the rear portion of the cylinder (21) and is connected to a suction device.

16. Apparatus according to claim 15, characterized in that the piston (24) has such a clearance in the cylinder (21) that air can flow past the piston (21) and the granular desiccant (6) cannot flow past the piston (21).

Images