METHOD AND DEVICE FOR WELDING TWO HOLLOW PROFILED RODS MADE OF PLASTIC

Abstract

A method for welding two hollow profiled rods made of plastic to form a window frame. The profiled rods to be joined together are heated to a predetermined temperature by inserting a welding plate between their connecting surfaces and pressing the same against the welding plate, forming outer and inner beads, and the profiled rods are pressed together under pressure after removing the welding plate, with a simultaneous increase in the size of the weld bead. For all cross sections of the profiled rods and the plastics used for manufacturing the window frames, to obtain a type of shadow groove on the top side and/or front side and on the bottom side and/or rear side of the finished window frame in the area of or near the connecting sites of the finished window frame, only the outer beads formed on the visible surface of the subsequent window frame in the area of or near the connecting sites of the two profiled rods are pressed slightly inward after removing the welding plate forming an oblique edge, and then are removed together with the inner beads, and then the connecting surfaces of the two profiled rods are joined together.

Claims

1. A method for welding two hollow profiled rods (4) of plastic to form a window frame, wherein the profiled rods (4) to be joined together are heated to a predetermined temperature by inserting a welding plate (3) between a connecting surface and pressing against the welding plate (3), forming outer and inner beads (8a, 8b), and are pressed together under pressure after removing the welding plate (3) with a simultaneous increase in the size of the weld bead, the method comprising after removing the welding plate (3), only the outer beads (8a) formed on a visible surface of the subsequent window frame near the connecting sites of the two profiled rods (4) are pressed slightly inward forming an oblique edge, and then are removed together with the inner beads (8b), and then the connecting surfaces of the two profiled rods (4) are joined together.

2. The method according to claim 1, wherein after removing the inner and outer beads (8a, 8b), the welding plates (3) are again moved briefly between the connecting surfaces of the profiled rods (4), and the connecting surfaces and are reheated.

3. A device for carrying out the method according to claim 2, wherein a welding head and a welding plate (3) and two tension units, each of which has an upper and a lower bordering ramp, receiving the two profiled rods (4) and press the connecting surfaces against the welding plate (3), wherein at least one slide (2) that is movable at a right angle to the visible surface of the subsequent window frame is arranged near the mutually facing end faces of each bordering ramp (1) for shaping the beads (8a, 8b).

4. The device according to claim 3, wherein an effective end face (5) of each bordering ramp (1) runs at an angle of approximately 45 to 70 to a base surface of said bordering ramp.

5. The device according to claim 4, wherein the slide (2) has a wedge-shaped cross section, a free end face (7) together with the base surface of each bordering ramp (1) forms a right angle or approximately a right angle.

6. The device according to claim 5, wherein a separating device is designed as a blade (9) and can be moved parallel to a surface of the subsequent window frame and is provided for each bordering ramp (1).

7. The device according to claim 6, wherein the two separating devices of a window corner are both guided on a common carriage.

8. The device according to claim 7, wherein the two separating devices are held on the carriage so they are adjustable in height.

9. A device for carrying out the method according to claim 1, wherein a welding head and a welding plate (3) and two tension units, each of which has an upper and a lower bordering ramp, receiving the two profiled rods (4) and press the connecting surfaces against the welding plate (3), wherein at least one slide (2) that is movable at a right angle to the visible surface of the subsequent window frame is arranged near the mutually facing end faces of each bordering ramp (1) for shaping the beads (8a, 8b).

10. The device according to claim 9, wherein an effective end face (5) of each bordering ramp (1) runs at an angle of approximately 45 to 70 to a base surface of said bordering ramp.

11. The device according to claim 3, wherein the slide (2) has a wedge-shaped cross section, a free end face (7) together with the base surface of each bordering ramp (1) forms a right angle or approximately a right angle.

12. The device according to claim 3, wherein a separating device is designed as a blade (9) and can be moved parallel to a surface of the subsequent window frame and is provided for each bordering ramp (1).

13. The device according to claim 12, wherein the two separating devices of a window corner are both guided on a common carriage.

14. The device according to claim 13, wherein the two separating devices are held on the carriage so they are adjustable in height.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] This invention is described in greater detail on the basis of an exemplary embodiment, which is shown in greatly simplified form in the drawing and is not drawn to scale.

[0011] FIGS. 1-5 show details of the main parts of a device for carrying out the invention in successive method steps according to embodiments of this invention.

DETAILED DESCRIPTION OF THE INVENTION

[0012] In FIGS. 1-4 of the drawings, the device according to this invention for welding profiled rods forms an essentially known window frame, only one so-called bordering ramp 1, a slide 2 and a welding plate 3 as shown with these being components of a welding head, which is essentially known and is therefore not shown here. The bordering ramp 1 shown sits on the top side of a hollow profiled rod 4 made of plastic, only portions of which can be seen, its two end faces being cut to specification and its internal continuous chambers normally being of different sizes due to appropriately arranged webs. On the bottom side of the profiled rod 4, which cannot be seen in the figure, there is a second advantageously identical bordering ramp 1, which is arranged in mirror image to the first bordering ramp 1, such that the profiled rod 4 is clamped between the two bordering ramps 1 and protrudes above the end face 5 of the bordering ramp 1, which runs obliquely and protrudes there by a predetermined amount, usually approximately 3 mm. This end face 5 runs at an acute angle of approximately 45 to 70, advantageously less than 60. A slide 2 having a wedge-shaped cross section and an end face 7 running at a right angle to the profiled rod 4 is guided displaceably on the end face 5, so that there is a right angle or approximately a right angle here between the end face 7 and the base surface of each bordering ramp 1.

[0013] As shown in FIG. 5, the mentioned welding head has a second profiled rod 4, which is also clamped between two bordering ramps 1 in the manner described above, and with which a slide 2 is also assigned to the bordering ramp 1. This arrangement is known to be provided in mirror image on the other side of the welding plate. It may be assembled with two, four or six welding heads, depending on the design of the welding system.

[0014] To initiate the welding and/or joining operation now, the welding plate 3, which is normally outside of the area of the profiled rods 4 and is heated, is inserted between the end face and the connecting face of the two profiled rods 4, wherein each bordering ramp 1 is initially a distance of approximately 3 mm from the welding plate 3 (FIG. 1). Now the profiled rods 4 are pressed against the welding plate 3 with a predetermined force. Therefore, the end face and/or the connecting face of the two profiled rods 4 each is heated and partially melted. The size of the pressing force of the profiled rods 4 on the welding plate 3 is retained here, so the distance between each bordering ramp 1 and the welding plate 3 is reduced, and a bead 8a, 8b (FIG. 2) is formed both outside and inside the wall of each profiled rods as well as on all webs situated in the interior of the profiled rods 4, its shape possibly being different and differing from the shape shown in simplified form here. As soon as the distance between the bordering ramp 1 and the welding plate 3 has been reduced by approximately , which is approximately 2 mm, the pressing force is reduced, and the profiled rods 4 are retracted from the welding plate 3. Next the welding plate 3 is removed from the area of the profiled rods 4.

[0015] The slide 2 is operative next. By a drive (not shown) of a known design, the slide is moved out of its position according to FIGS. 1 and 2 and into the position shown in FIG. 3 by moving along the end face 6 of the bordering ramp 1. In this position, the tip of the slide 2, which is advantageously slightly rounded, is approximately at the center of the thickness of the outside wall of the profiled rod 4. With this movement of the slide 2, the resulting outer bead 8a, which is still in a plastic condition due to the heating that has preferably occurred, is necessarily pressed inward and/or downward, e.g., by approximately 1.1 mm, whereupon the two weld beads 8a and 8b are combined to form one larger bead 8c, the shape of which also does not correspond exactly to the shape drawn in the figure (FIG. 3).

[0016] In a subsequent step, a blade 9 mounted on a carriage (not shown), for example, is used as the separating device, which is moved at a right angle to the plane of the drawing along the end face 7 of the slide 2, wherein at least most of the bead 8c of the profiled rod 4 is separated (FIG. 4). It can be advantageous if the carriage (not shown) holds another blade 9, so that most of the bead 8c is separated at the same time on both end faces of the profiled rods 4 being connected to one another. Thus, the two separating devices of a window corner are guided on a shared carriage, and the two separating devices can be held on the carriage in such a way (not shown here) that they are adjustable in height. The separated parts of the beads 8c can then be removed by a stream of air, for example, out of the area of the profiled rods 4 being connected to one another. Following that, the two slides 2 are first moved back so far away from the profiled rods that they are outside of the wall, as can be seen clearly in FIG. 5. Next, the end faces of the two profiled rods 4, which have been mitered and are still in the heated and therefore plastic state, are pressed against one another and welded (FIG. 5). This figure also shows that a small groove 10 having a V-shaped cross section remains at the surface between the two profiled rods 4 in the area of or near the connecting site. This groove 10 may also have a slightly different shape, depending on the design of the tip of the slide 2.

[0017] It is possible to move the welding plate 3 again into the area of the two profiled rods 4 after removing the separated beads 8c and to again press the profiled rods 4 against the welding plate 3. However, this pressing operation is carried out only briefly and with an extremely low pressing force, so that the length of the profiled rods 4 is shortened only insignificantly as a result, but the end faces of the profiled rods 4 are heated again. Such a brief pressing operation is understood to be a period of approximately 2 sec. to 15 sec., depending on the type and thickness of the material of the profiled rods 4.

[0018] It is known that the profiled rods 4 may be made of plastic to form a window frame, the upper and/or front surface of which is rarely completely planar. In most cases, an inclination or a rounded surface is provided on the inner and/or outer edge. To also ensure that an outer bead is no longer being formed even in these areas, for example, the slide 2 may be designed to be profiled. It is possible for at least two separate slides 2 to be provided, of which the second slide 2 runs at an angle to the first slide 2.

[0019] German Patent Reference DE 10 2017 111 606.0, filed 29 May 2017, the priority document corresponding to this invention, to which a foreign priority benefit is claimed under Title 35, United States Code, Section 119, and its entire teachings are incorporated, by reference, into this specification.