DD246062A1 - MEASURING SENSOR FOR TACTILES SENSOR - Google Patents

Abstract

On automatic welding systems for MIG, MAG and UP welding, malfunction of tactile sensors due to rust, scale and paint layers must be avoided. A measuring contact for tactile sensors which reacts to direct electrical contact as well as to mechanical deflection is achieved according to the invention in that a stylus 1 is fixed radially and axially without functional contact with a workpiece 3 by means of a membrane 2. To reinforce or when using a membrane 2 with less flexibility, a compression spring 4 may additionally be arranged axially behind the membrane 2. High-melting electrically conductive material as stylus 1 is responsible for a trouble-free flow. Upon electrical contact of the stylus 1 with the workpiece 3, a signal to the robot controller 11 is given by the sensor evaluation unit 10. If no electrical contact is possible, it comes with further approach of the welding head to the workpiece 3 to a deflection of the stylus 1 and electrical contact between stylus 1 and contact element 8. The Sensorauswerteeinheit 9 is responsible for the mechanical deflection of the stylus. Fig. 1

Description

To ensure proper functioning, the contact element 8 and the workpiece 3 have the same potential and the stylus 1 forms another potential. Upon electrical contact of the stylus 1 with the workpiece 3 is given by the Sensorauswerteeinheit 10, a signal to the robot controller 11. Is due to rust or scale on the workpiece 3 no electrical contact possible, it comes with further approach of the welding head to the workpiece 3 to a deflection of the stylus 1 and to an electrical contact between the stylus 1 and the contact element 8. Parallel draws the sensor evaluation unit 9 is responsible for the mechanical deflection of the stylus 1. In order to be able to correct a horizontal and vertical guidance of a robot welding torch according to FIG. 2, it is advantageous to arrange two feeler pins in parallel on the welding torch of the robot.

Claims (2)

Invention claim: 1. Probe for tactile sensor, softer responsive to direct electrical contact as well as mechanical deflection, characterized in that a stylus (1) without functional contact with a workpiece (3) by means of a membrane (2) is radially.und axially fixed. 2. Sensor for tactile sensor according to item 1, characterized in that for enhancing the effect of the membrane (2) in addition a compression spring 4 is arranged axially behind the membrane (2). For this 2 pages drawings Field of application of the invention The invention relates to a sensor for tactile sensor, in particular for automatic welding systems for MIG, MAG and UP welding and preferably for use in arc welding robots. Characteristic of the known technical solution It is known to use seam tracking sensors to compensate for manufacturing tolerances for seam tracking on welding machines, especially on welding robots. Especially seams with small fillet thicknesses and small material thicknesses of the joining parts are hardly due to the repeatability of the robot, manufacturing tolerances of the components and distortions of the parts during welding without seam tracking sensors in the required quality. The most commonly used sensors are tactile, inductive, capacitive and arc sensors. Arc sensors require a high control engineering effort and the exact compliance with a variety of boundary conditions. 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, since these systems cover a large sensed area and concave and convex paths can not be distinguished. Tactile sensors, which work with electrical potential difference between sensor and workpiece, have a punctiform sampling and with highly curved paths, a constant distance of the burner is ensured. Conditions for the functioning of such systems are metallically bright surfaces, which can usually only be achieved by mechanical methods such as blasting or tumbling. Rust and scale layers considerably impair the functionality or render the sensor ineffective. This can result in additional effort to ensure the sensor use, which makes the product more expensive. Object of the invention The aim of the invention is to avoid malfunction of tactile sensors by rust, scale and paint layers. Essence of the invention The invention has for its object to develop a responsive to direct electrical contact and mechanical deflection sensor for tactile sensors. According to the invention the object is achieved in that a stylus is fixed radially and axially without functional contact with a workpiece by means of a membrane. To reinforce the membrane, a compression spring is additionally arranged axially behind the membrane. embodiment The invention will be explained below with reference to an embodiment with associated figures. Fig. 1: Schematic representation of a sensor with additional compression springs behind the diaphragm Fig. 2: Schematic representation of parallel arranged sensor on a welding torch The sensor shown in Figure 1 for a tactile sensor is used for horizontal guidance of a welding head during fillet welding. A stylus 1 is made of a tungsten-torium alloy to prevent the adhesion of spatters. A receptacle 4 and a nut 5 of the axial position assurance of the stylus 1 by supporting the membrane 2 in the housing 6. A contact element 8 is separated by means of an insulating layer 7 from the housing 6. In addition, behind the membrane 2, a compression spring 4 may be arranged axially in such a way that the effect of the membrane can be enhanced or a membrane 2 with low flexibility can be used.