DD265100A1 - DEVICE FOR OPERATING A WELDING HEAD - Google Patents

Abstract

In particular, in the automatic welding of Kehlnaehten and the use of automatic welding systems for MIG, MAG, TIG and UP welding should be done by means of the device tactile sampling of a weld. The solution provides that between a high-melting material stylus 1 and a clamping 2 of the Meßfuehlers a highly elastic mold element 3 is assigned such that in case of lack of electrical contact between the stylus 1 and the foot parts 4; 5 a Nachfuehrung the welding torch 6 is carried out until the Meßfuehler the contact pieces 7; 8 approaches to an electrical connection. Fig. 1

Description

On the shaft of the welding torch, the adjustable contact pieces, which have the same electrical potential as that of the parts to be joined, are arranged in isolation. Will u.a. by a local contamination of the parts to be joined, such as scale or rust, dor direct electrical contact between the stylus and parts to be prevented, takes place on further approach of the probe to the shaft of the welding torch, the electrical contact of the probe with the contact pieces. This makes three operating states possible

- Electrical contact of the probe with the adherend

- electrical contact of the probe with the contact piece (disabled direct electrical contact with the adherend)

- no electrical contact of touch probe and joining part as well

no electrical contact of the probe with the contact piece, if in both cases the sensor is removed from the joining part.

embodiment

The invention will be explained in more detail below using an exemplary embodiment. The accompanying drawings show

Fig. 1: Representation of the welding head with sensor system ' Flg. 2-4: Representation of the three operating states of the sensor system

FIG. 1 shows a welding torch 6 for inert gas welding processes with a sensor system. The probe 1 of the sensor is made of a tungsten alloy, which prevents sticking of splashes v> * d. There is a highly elastic mold element 3 in the form of a compression coil spring, which is arranged in isolation in the clamping 2 of the probe between the probe tip 1 and a clamping 2 of the probe. If it comes as a result of rusted or scaled surfaces of the joining parts 4; 5 when touching the stylus tip 1 with the joining parts 4; δ not for electrical contact, there is also no signal from the Sensorverarboitungseinheit 9 to the control of the welding robot 10, so that the welding torch 6 in the sensor operation continues to move to the joining part 4 or 5. In this case, deforms the mold element 3 in the form of the compression coil spring to the electrical contact between the contact sleeve 11 of the probe and the contact pieces 7; 8. The thus supplied to the robot control signal causes an opposite movement of the welding torch 6. The mold element 3 in the form of the spring is relieved and the sensor returns to its original position. To adjust the distance contact piece 7; 8 and contact sleeve 11 are the contact pieces 7; 8 designed as an eccentric ring. By loosening the nut 12, by turning the eccentric rings, the distance between the contact sleeve 7; 8 and eccentric ring are infinitely eingeetelllt and fixed. The mold element 3 as a highly elastic compression coil spring of the probe prevents even in unwanted operating conditions plastic deformation or destruction of the probe. Operating conditions of this kind can u. a. due to incorrect operation, failure of the sensor processing unit or failure of peripheral devices. According to Fig. 2, there is a physical contact between the Taslspitze 1 and the joining part 4. When bare joining parts thus takes place also an electrical contact and a signal to the robot controller.

In the absence of electrical contact, the welding torch 6 continues to approach the joining part 4 and the shaped element 3 (compression coil spring) deforms until a contact between the contact piece 7 and contact sleeve 11 is made. (Fig.3) The gem. Fig. 4 illustrated operating state shows when neither a contact between the probe tip 1 and the joining part 4 is still between dom contact piece 7 and the contact sleeve 11.

Claims (2)

Apparatus for guiding a welding head to obtain signals about the distance of a welding torch from an ideal line of action by means of a combination of elastically movable and electrically contacting sensors and to ensure the position of the sensors after undesired operating conditions, characterized in that between one of refractory Material existing stylus (1) and a clamping (2) of the probe a highly elastic form element (3) is arranged such that in the lack of electrical contact between the stylus (1) and joining parts (4, 5) tracking the welding torch (6) so is long, until the probe approaches the contact pieces (7, 8) to an electrical connection. For this 2 pages drawings Field of application of the invention The invention relates to a device for guiding a welding head for the tactile scanning of a welding joint. In particular, in the automatic welding of fillet welds and in the use of automatic welding systems for MIG, MAG, TIG and UP welding, preferably for use in arc welding robots, the device should be used. Characteristic of the known state of the art It is known to use seam tracking sensors to compensate for manufacturing tolerances on welding machines, especially welding robots. Especially seams with smaller fillet thicknesses and small material thicknesses of the parts to be joined can hardly be produced in the required quality due to the repeat accuracy of the robot, manufacturing tolerances of the components and warping of the parts during welding without seam tracking sensors. The most common sensors are inductive, capacitive tactile and arc sensors. About signal evaluation of the arc, it is possible to keep the burner exactly in the seam without additional attachments increase the burner volume or mass (DE-OS 2611377). Problems of seam searching outside of the welding times are not solvable in this way. Furthermore, this possibility is limited to a few process variants and a variety of boundary conditions must be observed. Capacitive and inductive sensors have a large size due to the need for cooling to reduce temperature drift, thereby hindering accessibility to the torch. Another disadvantage of such systems is the welding of curved seams, as these systems cover a large sensed area and concave and convex surfaces can not be distinguished. The simplest systems are based on a direct mechanical scanning of the joint, corner or edge (eg DE-AS 1615451). By mechanical forces, generated by compression springs or by gravity, the scanning system, which is rigidly coupled to the welding torch, pressed against the workpiece and thus created a unique assignment burner weld. The big forces lead to heavy wear. The feedback to the controller is missing. Tactile sensors, which work with electrical potential difference between sensor and workpiece have oine punctiform sampling and with highly curved paths a constant distance of the burner is ensured. In DD-PS 240685 a special touch probe is described, in which the probe tip is made of a refractory, electrically conductive material on a highly flexible element. As a result, seams can be welded in which other sensor systems would interfere. Conditions for the functionality of such systems are metallic bare surfaces, which are usually possible with hot rolled material only by mechanical processing. Rust and scale layers impair the functionality or make the sensor ineffective. Systems that evaluate the mechanical deflection of the feeler (DD-PS 236 471) have a large volume and are very sensitive to undesirable operating conditions such as overshoot of the robot or collision. When welding outside the sensor preferred direction disturb the feeler. Even in the solutions described in US 3171012 undesirable operating conditions lead to deformation of the tactile feeler. Object of the invention The present invention aims to provide a sensor system with low volume, low cost, simple technical means and high reliability. Explanation of the essence of the invention The invention has for its object to gain signals by means of combination of elastically movable and electrically contacting sensor signals on the distance of the welding torch from the ideal line of action and to ensure the reproducibility of the sensor position even after undesirable operating conditions. According to the invention, the sensor consists of a clamping shaft, an elastic mold element and a refractory, electrically conductive stylus.