This application claims priority to European Patent Application No. 19202442.0, filed on Oct. 10, 2019, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method for producing a butt-welded joint between two pipe segments of a pipe made of a weldable plastic material, each pipe segment being held by a gripping means, pipe end cross-sections of the pipe segments being machined with the aid of a tool means for forming welding contact surfaces, said welding contact surfaces being melted by means of a heating means and in the following being pressed against each other with a joining pressure for forming a butt weld which connects the pipe segments with each other in a joining plane. Moreover, the invention relates to a device for carrying out the method.

BACKGROUND OF THE INVENTION

From DE 10 2012 207 098 A1, a method and a device for producing a butt-welded joint between two pipe segments of a plastic pipe which are each held by a gripping means are known, in this method a gripping means taking hold of each of the pipe segments which are produced by way of separating cuts before they are disposed in the device, and opposite pipe end cross-sections of the pipe segments being machined one after the other with the aid of a tool means in order to form welding contact surfaces. For employing the tool means, it is moved into a clearance formed between the welding contact surfaces in the device in order to process the pipe end cross-sections subsequently upon supplying of the pipe segments by the gripping means with an axial supply movement. After the machining has been carried out for producing the welding contact surfaces, the tool means is replaced by a contact heating appliance, which is moved into the clearance formed between the pipe segments like the tool means.

For generating the butt weld, the welding contact surfaces, which are melted by means of the contact heating appliance, are lastly pressed against each other with a joining pressure after the contact heating appliance has been removed from the clearance formed between the pipe segments. The finished pipe connection is then removed manually corresponding to the placement of the pipe segments in the device which was effected previously.

When using the known device, it has in particular proven to be disadvantageous that the preparation of the pipe segments as a condition for producing the butt-welded joint requires a plurality of manufacturing or operation steps, which lead to correspondingly long construction times in particular in plant construction in connection with the piping systems, which are often intricate and have a plurality of pipe connections.

OBJECT AND SUMMARY OF THE INVENTION

The object of the present invention is therefore to propose a method and a device which simplify the production of pipe connections between pipe segments of plastic pipes in terms of reducing the manufacturing and operation steps, thus making correspondingly shorter construction times in plant construction possible.

In order to attain this object, the method in accordance with the invention has the features of claim1.

Corresponding to the method in accordance with the invention, the tool means is disposed in a stationary manner in a separating plane for machining the welding contact surfaces and a separating cut, for forming the pipe segments, is realised by the gripping means moving the pipe relative to the tool in the separating plane, said separating cut simultaneously serving to form the welding contact surfaces.

In accordance with the invention, the tool means, which generates the welding contact surfaces by machining the pipe end cross-sections, thus simultaneously serves to form the pipe segments by means of a separating cut cutting through the pipe. Here, the movement of the pipe relative to the tool means performed by the gripping means makes different orientations of the separating plane relative to a longitudinal pipe axis possible so that not only separating cuts in a separating plane which is disposed at an angle of 90° in relation to the longitudinal axis, but also any other separating angle can be set without the way how the pipe is held in the gripping means having to be changed.

It also proves to be particularly advantageous that arranging the tool means in a stationary manner for machining the welding contact surfaces makes it possible to employ a milling tool, which is in particular formed as an end mill, for simultaneously generating the pipe segments by separating the pipe in a separating plane and the surface finishing of the pipe end cross-sections for forming the welding contact surfaces in one process step.

In a preferred embodiment, each gripping means is guided by a handling means on a circular movement path in a movement plane which is parallel to the separating plane in order to perform the relative movement. Here, the longitudinal axis of the pipe tumbles in the separating plane while the separating cut is being realised, the tumbling angle corresponding to the inclination of the separating plane relative to the normal plane of the pipe. Thereby, separating cuts can be generated which make pipe connections having any pipe angle between 0° and 90° possible due to a following joining process of the pipe segments which are askew by 180° with respect to each other without the way in which the pipe segments are held in the gripping means having to be changed.

It is particularly advantageous if the pipe is grasped at a pipe end by a gripping means before the separating cut is realised and is displaced from a supply position into a processing starting position adjacent to the tool means, the second pipe end being grasped by the second gripping means in said processing starting position and both gripping means placing the pipe at the disposal of a cutting tool of the tool means for realising the separating cut.

In this way, it is not only possible to handle the pipe relative to the tool means by means by means of the gripping means, but it is also possible that one of the gripping means is used as a transfer means for withdrawing the pipe from a magazine means disposed in a supply position into a processing starting position.

It is particularly advantageous if the gripping means move each of the pipe segments until their welding contact surfaces are in contact with a heating surface of the heating means, which is disposed between the welding contact surfaces, after the separating cut has been realised.

In the case of a preferred embodiment of the heating means as a contact heating appliance, the welding contact surfaces are moved until they rest against the heating surfaces. In case the heating means is alternatively embodied as a radiant heating appliance, the welding contact surfaces can be positioned at a distance to the heating surfaces.

As has already been emphasised to be advantageous in connection with the tool means disposed in a stationary manner, supplying the pipe segments provided with the welding contact surfaces to a stationary heating means also proves to be advantageous since the focus can thus be put on effectiveness alone when realising the heating means, i.e. in particular on the heating-up time which can be achieved, without having to consider to the manageability or the possibilities of positioning the heating means.

If, after the welding contact surfaces have been heated, the welding contact surfaces are arranged opposite each other and parallel to each other and are moved against each other by way of a supply movement which is performed by at least one gripping means and serves to form a material connection in a joining plane, it is possible to freely choose the relative position of the joining plane relative to the separating plane and/or the heating means.

Preferably, the welding contact surfaces are heated up by means of a heating means which is disposed adjacent to the tool means in a stationary manner and the pipe segments are joined in a joining position adjacent to the heating means so that the paths the gripping means have to conduct with the pipe segments can be minimised.

It is also particularly advantageous if machining of the pipe end cross-sections for forming the welding contact surfaces, heating-up of the welding contact surfaces and joining of the welding contact surfaces take place in a common processing plane which is disposed between the handling means.

The device in accordance with the invention has the features of claim8in order to attain the object.

In the inventive device for producing a butt-welded joint between two pipe segments, the tool means is disposed in a stationary manner and the gripping means can be moved independently of each other in the direction of the spatial axes for handling the pipe segments relative to the tool means.

It is particularly advantageous if the heating means is disposed in a stationary manner and adjacent to the tool means.

Each of the gripping means is preferably disposed at a handling means having multiple movement axes, wherein it is particularly preferable if the handling means are formed as robots having at least five axes, wherein the gripping means have a sixth axis, in particular for performing a gripping movement. Embodying the handling means as a robot having six axes is particularly preferable.

If the tool means and the heating means are disposed in a common processing plane between the handling means which are each disposed in a stationary manner, it is possible to make the movement space of the handling means as small as possible so that robots having relatively small ranges make it already possible to perform the method in accordance with the invention.

The heating means can particularly advantageously be embodied as a contact heating means or radiant heating means.

