DE19615204C1 - Table-mounted butt welding equipment for joining thermoplastic pipes - Google Patents

Abstract

Table-mounted equipment for butt welding of plastic pipes comprises a base(1) with a lower face (2), a first clamping face for a pipe holder, a first, front linear guide (8) and a second, rear linear guide (9) for a slide (11) with a second clamping face for a further pipe holder. The second linear guide (9) is further from the base surface (2) than the first linear guide (8). Slide (11) movement brings the coaxial pipe holders towards each other. A pipe end planing tool (20) between the pipe holders is interchangeable with a heating element for plasticising the pipe ends and the plane (20) or heating element are moved laterally along and swivelled around a third linear guide (19).

Description

The invention relates to a device for butt welding thermoplastic pipes, in particular as a table device for pipes diameter up to 250 mm, with a machine bed with a footprint and with a first clamping surface for at least one pipe holder and with a first, front linear guide and one arranged behind it second linear guide for a slide, which has a second clamping surface for at least one further pipe holder, with the Slide at least two coaxial tube holders against each other are, with a planer for the pipe ends, with one against the Replaceable planing heating element for plasticizing the planer Tube ends and with a third linear guide for permanent storage, Cross-shifting and swiveling movement of the planer and heating element.  

Devices of this type are required to make line sections thermoplastic pipes used to transport fluid media serve to weld together tightly and mechanically highly resilient. The properties of such welded joints are based on existing standards made extremely high demands, for example must the formation of clearly visible welding beads can be seen. At the planer is at least one rotating disc that is provided with a cutout and a planing knife. When planing the planer is swung in between the two pipe holders, whereby the plane axis coincides with the axes of the pipe ends. The first only roughly pre-cut pipe ends are then against the planer shifted so that two annular cut surfaces are created, the exact run radially. The distance between the pipe ends then becomes again enlarged and the planer from its working position into one Rest position swung out, switched off and laterally on one corresponding linear guide shifted. On the same linear guide there is a plate-shaped heating element that is preheated accordingly and in the place of the planer in the distance between the Pipe ends is pivoted into it. Then the two pipe ends relatively displaced against the heating element under flat contact and - preferably by means of a program control - to the required Brought welding temperature. Then the heating element is switched off again pivoted back into a rest position, whereupon the plasticized pipe ends with corresponding force against each other be moved so that they are absolutely tight and mechanically high be resiliently connected. Both the planer as well the heating element are free on their common linear guide slidable so that they are always exactly in the middle between the two Can adjust pipe ends.  

In known devices of the type described above, this is Machine bed cuboid with a horizontal surface. The axes of the linear bars are located here guides that serve for the counter movement of the pipe holder, also in a horizontal plane. The linear guides are used for guidance a carriage on which at least one pipe holder is attached. A such an arrangement is also described in EP 0 453 903 A2. Also here the machine bed or base frame is cuboid with a horizontal surface.

Due to obvious prior use is a series of generic prior known directions in which the machine bed and the carriage close an approximately cuboidal structure, if one from one for the Movement of the slide required free space between a vertical wall the machine bed and the carriage. The axes of three rod-shaped linear guides also lie horizontally Level.

Due to obvious prior use, non-generic plastics continue to be used pipe welding machines for large pipe diameters up to 630 mm known in which in a base frame over its entire length two rod-shaped horizontal linear guides for four pipe holders are clamped, of which the rear linear guide is arranged higher than the front one. However, these devices have no clamping surfaces for pipe holder. Rather, the pipe holders are diametrical opposite points with bearing bushes for direct guidance on the linear guides, and two of them are hydraulic driven. A third linear guide for the alternating use of Planer and heating element are missing; rather, these are only temporary carried by the linear guides for the pipe holder and must be in the train of the workflow exchanged by hand during a welding process will.  

In the known generic devices, the following occur Disadvantages on: The pipe holder, which transmit considerable axial forces must form lever arms of considerable length. This promotes a certain stiffness of the Slide on the linear guides. By the height of the machine bed and the additional height of the linear guides and the tube holder has that entire device has a considerable overall height. Because such devices usually are placed on a work table, the are to observing and operating parts in an unfavorable position for the operator.

The invention is therefore based on the object of a device described genus to improve in that the heavy Sliding movement on the linear guides reduced and the Ease of use and the ability to observe are facilitated and improved will.

The solution to the problem is the one specified at the beginning Device according to the invention in that the second linear guide has a greater distance from the footprint of the machine bed than the first, front linear guide.

This is the one given by the axes of the two linear guides Work level to a certain extent towards the operator inclined so that they operate the device more easily and the individual Can better observe and influence work processes. At least compared to the second linear guide, the lever arm is also the Pipe holder shortened. So the machine bed is through the relative position of the two linear guides to each other according to the invention ergonomically designed. This is particularly the case if the  Height difference "H" between the first linear guide and the second Linear guide is between 10 and 100 mm.

It is particularly advantageous if the machine bed and the Carriage in the area of the second linear guide with the protruding upwards Wall parts are provided in which the second linear guide, formed as a guide rod, is mounted.

This measure allows the machine bed in the direction of the loading servant be trained even more sloping.

Further advantageous configurations of the subject matter of the invention result from the other subclaims.

An embodiment of the subject matter of the invention is explained below with reference to FIGS . 1 to 8.

Show it:

Fig. 1 is a front view of the complete device,

Fig. 2 is a vertical section through the article of FIG. 1 along the line II-II,

Fig. 3 is a side view in the direction of arrow III in Fig. 1, but without a heater and without planer, and

FIGS. 4 through 8, the lever ratios of the prior art and subject of the invention in a comparatively representation.

In Fig. 1 a machine bed 1 is shown, which has a mounting surface 2 to be placed on a work table or the like. The machine bed 1 has a clamping surface 3 which is already significantly lower than the clamping surfaces in the prior art. A fixed but adjustable pipe holder 5 is fastened on this clamping surface 3 by means of a first angle piece 4 . A second angle piece 6 can be used to fasten a further tube holder, not shown here. The machine bed 1 also has a left side wall 7 . In the machine bed 1 , the left ends of two linear guides designed as round rods are fastened, namely a front first linear guide 8 and a second linear guide 9 , which are arranged in staggered height and the right ends of which are fastened in the right side wall 10 of the machine bed 1 . On the linear guides 8 and 9 , a slide 11 is displaceable in a corresponding recess in the machine bed 1 , specifically by means of a toothed rack 12 ( FIG. 2) attached to the slide 11 , into which a pinion (not shown here) engages from below, which at the end a shaft 13 is attached, which is driven by a turnstile 14 by hand.

The top of the carriage 11 is formed by a further clamping surface 15 on which a second tube holder 17 is adjustably attached by means of a further angle piece 16 . By means of yet another angle piece 18 , an additional tube holder, likewise not shown here, can be fastened on the slide 11 . The clamping surfaces 3 and 15 lie in a common, horizontal plane. The pipe holders 5 and 17 are concentric with respect to a common axis AA, this axis also defining the position of the axes of the pipe ends to be welded together. The tube holder 5 and 17 are formed as clamping rings and can be clamped firmly on the articulated connection 41 diametrically opposite side by a clamping spindle 42 against the pipe to be machined.

As is apparent from Fig. 3, the elbow 6 is formed on its upstanding leg 6 a according to the tube diameter as a partial cylinder surface. The same applies to the leg 18 a of the angle piece 18th This makes it possible to use the legs 6 a and 18 a even without an annular pipe holder 5 and 17 as a pure support body for the pipes to be welded.

On a third, rear linear guide 19 ( FIG. 2) - parallel to the linear guides 8 and 9 - a planer 20 and a plate-shaped heating element 21 are pivotally arranged. The planer 20 is driven by a hand drill 22 , which is detachably connected to the planer 20 at a great distance from the AA side. The planer 20 can consequently be pivoted into the distance between the tube holders 5 and 17 without hindrance by the tube holder 17 with its axis of rotation concentric to the axis AA by means of a hand lever 23 . In the rest position, the heating element 21 is surrounded on both sides by a contact protection 43 which consists of two sheet metal disks which are connected by a spacer bolt 44 and are pivotably and displaceably mounted on the third linear guide 19 .

After the planing of the two pipe ends by the planer 20 has ended, the latter is pivoted back into its rest position about the linear guide 19 and shifted to the right. The preheated heating element 21 now takes the place of the planer 20 and is likewise pivoted into the space between the tube holders 5 and 17 by means of a hand lever 24 . The sequence of the steps and the effects has already been stated in the introduction.

It can be seen from FIGS. 2 and 3 that there are two bearing blocks 25 on the rear of the machine bed 1 , between which the third linear guide 19 is clamped. Fig. 2 shows the planer 20 in its working position. It has two disks 27 driven by the hand drill 22 within a housing 26 , only one of which is visible. The disk 27 has a cutout 28 for the chip passage and a knife 29 . In the housing 26 there is an electrical switch 30 , the stylus of which is supported in the working position on the linear guide 9 and thereby closes the switch 30 . This switch is in series with another switch which is located in the hand lever 23 and can be closed by means of a lever 31 . The circuit is closed by connecting the two switches in series, so that any risk of an accident is excluded, since the planer 20 cannot be switched on outside of its working position. A stop 32 , which bears against the rear of the machine bed 1 , prevents the planer 20 from pivoting back too far.

It can be seen in particular from FIG. 2 to what extent the linear guides 8 and 9 , which are at a distance D, are successively arranged in height, the height difference being defined by the dimension H. This difference in height can, for example, be between 10 and 100 mm, or larger for larger machines.

The axes of the linear guides 8 and 9 define a virtual working plane EE, which runs down to the front 33 of the machine bed 1 . The course of the working plane EE is essentially followed by the upper side of the machine bed 1 , which, below the linear guides 8 and 9 and the movement path of the slide 11, has a top wall 34 which is lowered relative to the side walls 7 and 10 and slopes towards the front 33 . It can be seen that below the carriage 11 the machine bed 1 , which is designed as a shell-shaped casting, has a very particularly low height.

The housing 26 of the planer 20 also has a cantilever 35 which is supported from above on the front linear guide 8 and engages under it by means of a hook 36 so that the oscillating reaction forces of the planer 20 are intercepted.

As can be seen from FIG. 3, not only the top wall 34 ( FIG. 2) has a course falling towards the front. Rather, the side walls 7 and 10 also have surfaces 37 and 38 , which slope towards the operating side. As can be seen, the sloping surfaces 37 and 38 are arched upwards.

As can be seen again from Figs. 1 and 3, the machine bed 1 and the carriage 11 in the region of the second upper linear guide 9 with upwardly projecting wall parts are provided 39 and 40 which are approximately semi-cylindrical and in which the second linear guide 9 is mounted . This also ensures that, despite a relatively high position of the second linear guide 9, the front of the machine bed 1 is designed to be particularly low, and the clamping surfaces 3 and 15 are once again clearly offset from the wall parts 39 and 40 towards the bottom.

The relationships are explained more clearly with reference to FIGS. 4 to 7, which show partial sections from devices for a pipe diameter D of 160 mm, and with reference to FIG. 8.

FIGS. 4 and 5 show details of the prior public use previous model of the subject invention, and specifically, FIG. 4 is a front view and FIG. 5 is a side view in the direction of the arrow V in Fig. 4. On the carriage 11 a which on the linear guides 8 a and 9 a is slidable, a tube holder 17 a is attached. Whose lever arm h₁ compared to the axes of the linear guides 8 a and 9 a lying in a horizontal plane is 183 mm.

FIGS. 6 and 7 show the analog details of the subject invention, and specifically, FIG. 6 is a front view and FIG. 7 is a side view in the direction of the arrow VII in Fig. 6. The inclination of the plane E-E, in which the axes of the linear guides 8 and 9 lie, and the lowering of the clamping surface 15 thus enabled the lever arm h₂ of the tube holder 17 compared to this plane EE only 135 mm.

Fig. 8 shows in abscissa the displacement forces P (in N) of the tube holders against each other and on the ordinate the bending moments M (in Nm). Line 45 shows the situation in the prior art and line 46 in the subject of the invention. It is made clear that the tube holder in the subject of the invention is less stressed on bending than in the prior art. The advantages in terms of ergonomics have already been mentioned above. In addition, it should also be pointed out that the shortening of the lever arm results in less elastic bending deformation of the tube holder during the welding process. This significantly reduces the displacement of the two pipe axes, which in turn has a positive influence on the accuracy of the weld, in particular on the uniform formation of the weld beads on the pipe circumference.

Claims (8)

1. Device for butt welding thermoplastic pipes, in particular as a table device for pipe diameters up to 250 mm, with a machine bed ( 1 ) with a footprint ( 2 ) and with a first clamping surface ( 3 ) for at least one pipe holder ( 5 ) and with a first , front linear guide ( 8 ) and a second linear guide ( 9 ) arranged behind it for a slide ( 11 ) which has a second clamping surface ( 15 ) for at least one further tube holder ( 17 ), with at least two coaxial tube holders through the slide ( 11 ) ( 5 , 17 ) are displaceable against one another, with a planer ( 20 ) for the pipe ends, with a heating element ( 21 ) which can be exchanged for the planer ( 20 ) for plasticizing the pipe ends and with a third linear guide ( 19 ) for permanent storage, Transverse displacement and pivoting movement of the planer ( 20 ) and heating element ( 21 ), characterized in that the second linear guide ng ( 9 ) has a greater distance from the installation surface ( 2 ) of the machine bed ( 1 ) than the first, front linear guide. 2. Device according to claim 1, characterized in that the height difference "H" between the first linear guide ( 8 ) and the second linear guide ( 9 ) is between 10 and 100 mm. 3. Apparatus according to claim 1, characterized in that the third linear guide ( 19 ) for the planer ( 20 ) and the heating element ( 21 ) has a smaller distance from the installation surface ( 2 ) than the second linear guide ( 9 ) for the pipe holder ( 5, 17 ). 4. The device according to claim 1, characterized in that the machine bed ( 1 ) has surfaces ( 37 , 38 ) which slope towards the operating side. 5. The device according to claim 4, characterized in that the falling surfaces ( 37 , 38 ) are curved upwards. 6. The device according to claim 1, characterized in that the machine bed ( 1 ) and the carriage ( 11 ) in the region of the second linear guide ( 9 ) with upwardly projecting wall parts ( 39 , 40 ) are provided, in which the second linear guide ( 9th ), designed as a guide rod, is mounted. 7. The device according to claim 1, characterized in that the machine bed ( 1 ) below the linear guides ( 8 , 9 ) and the loading path of the carriage ( 11 ) one with respect to the side walls ( 7, 10 ) lowered to the front ( 33 ) has sloping ceiling wall ( 34 ). 8. The device according to claim 6, characterized in that the upwardly projecting wall parts ( 39 , 40 ) of the machine bed ( 1 ) and slide ( 11 ) have semi-cylindrical outer surfaces.