The invention relates to an electrode flatness controller used to control the position accuracy of upper and lower electrodes in robotic resistance welding probes, with measuring cylinders having a non-rotary structure, such measuring cylinders being resistant to external contacts and impacts, thereby ensuring repeatability and high accuracy of the measurements, further allowing to check angular variations in the electrodes through measurements at two points for each electrode, as well as generating feedback, based on measured engagement between the electrode holder and the electrode, to report that the service life of the electrode holder has expired, requiring replacement.

PRIOR ART Resistance welding employed in numerous fields such as automotive, aerospace technologies, steel structures, steel manufacturing, manufacturing of high-precision devices, electrotechnics and machinery is a process of jointing by means of the heat generated by the resistance of metal parts against the electrical current passed therethrough. The parts are partially melted to set up the medium required for welding, then electrical current is cut off and pressure is exerted on the workpieces followed by cooling under this pressure to ultimately yield a non-removable joint.

Correct position of upper and lower welding electrodes used in robotic probes is of great importance for the accuracy and quality of the welding process.

A so-called Tip Alignment Checker (TAC) device by OBARA to perform checks on the positions of the electrodes in robotic probes is disclosed, wherein two separate measuring cylinders positioned perpendicularly to each other are employed to carry out measurements by contacting the electrodes appropriately positioned. Once measurement has started, both cylinders simultaneously reciprocate to read and store cylinder positions at electrode contact points, which are then utilized as reference values for subsequent checks. One of the disadvantages in this device is that measuring cylinders are located within the impact area of the robot and installed without any protection. Any contact from the robotic probes at any time and in any manner hinders the accurate reading capability of the cylinders.

A further disadvantage is that the shafts of the measuring cylinders are lack of any measure against rotation. During the movement of the measuring cylinders, potential rotation of the shafts leads to faulty measurements by the high-precision sensors since such readings are relative to the magnetic ring in the piston hub inside the measuring cylinders.

A further disadvantage is that only the position shifts of the electrodes can be determined without the capability of measuring angular variations between the electrodes. Moreover, the wear condition of the electrode holder is not measured and therefore no data relevant for replacement intervals is generated.

As a result, the requirement to eliminate the drawbacks and disadvantages of current configurations and applications in the prior art has necessitated an improvement in the related technical field.

OBJECT OF THE INVENTION

The present invention relates to a resistance welding electrode flatness controller developed in order to eliminate the aforementioned disadvantages and introduce new advantages in the related technical field. The object of the invention is to provide for the construction of an electrode flatness controller as equipped with measuring cylinders having a non-rotary structure, such measuring cylinders being resistant to external contacts and impacts. Another object of the invention is to provide for the introduction of an electrode flatness controller offering repeatability and high accuracy of the measurements thanks to the construction of an electrode flatness controller as equipped with measuring cylinders having a non-rotary structure, such measuring cylinders being resistant to external contacts and impacts.

Yet another object of the invention is to provide for the construction of an electrode flatness controller, allowing to check angular variations in the electrodes in addition to position shifts, as well as generating feedback, based on measured engagement between the electrode holder and the electrode, to report that the service life of the electrode holder has expired, requiring replacement.

The structural and characteristic features and all advantages of the invention will be more clearly understood through the following figures as well as the detailed description with reference to such figures, therefore consideration should accordingly be made with reference to these figures and the detailed description.

BRIEF DESCRIPTION OF FIGURES

Embodiments of the present invention briefly summarized above and discussed in more detail below can be understood by reference to the exemplary embodiments of the invention illustrated in the accompanying drawings. It should be noted, however, that the appended drawings only illustrate typical embodiments of the present invention and are not to be construed as limiting its scope, as the invention may therefore allow for other equally effective implementations. In order to facilitate understanding, identical reference numerals have been used where possible to identify identical elements in the figures. The figures are not to scale and can be simplified for clarity. It is contemplated that the elements and features of an embodiment can usefully be incorporated into other embodiments without the need to further description.

Figure 1 : Representative perspective view of the article of the invention.

Figure 2: Representative exploded view of the article of the invention.

Figure 3: Representative detail view of the probes and probe holders of the invention.

REFERENCE NUMERALS

1. Main body

2. Measuring body

3. Controller 4. Bushing

5. Cylinder body

6. Cylinder shaft

7. Sensor

8. Floating joint connector 9. Probe

10. Probe holder 11. Fitting

12. Cylinder guard

13. Air unit bracket

14. Regulator 15. Valve

16. Upper electrode

17. Lower electrode

DETAILED DESCRIPTION OF THE INVENTION

Preferred alternatives of the resistance welding electrode flatness controller of the present invention in this detailed description are described solely for a better understanding of the subject without any limiting effect.

The invention relates to an electrode flatness controller used to control the position accuracy of upper and lower electrodes (16, 17) in robotic resistance welding probes, with measuring cylinders having a non-rotary structure, such measuring cylinders being resistant to external contacts and impacts, thereby ensuring repeatability and high accuracy of the measurements, further allowing to check angular variations through measurements at two points for each of the upper and lower electrodes (16, 17), as well as generating feedback, based on measured engagement between upper and lower electrodes (16, 17) and electrode holders, to report that the service life of the electrode holder has expired, requiring replacement.

In general, the article of the invention comprises at least one probe (9) to measure, instantly by contacting, the positions of upper and lower electrodes (16, 17), to determine angular variations by two-point measurements, and further to generate feedback reporting that the service life of the electrode holder has expired, requiring replacement, at least one probe holder (10) to support the measuring probes (9), at least one cylinder shaft (6) to drive reciprocal movement of the probes (9) and at least one cylinder body (5) accommodating such cylinder shaft (6), at least one bushing (4) to support linear movements of the probe holders (10) and the probes (9) attached thereto, at least one floating joint connector (8) to eliminate the misalignment between the cylinder shaft (6) and the probe (9), at least one sensor (7) to measure the positions of the probe (9), at least one cylinder guard (12) to protect the measuring cylinders from any impact, contact and external influence, at least one valve (15) to pneumatically actuate the cylinder shaft (6) driving the reciprocal movement of the probes (9), at least one regulator (14) to adjust the pressure of the air supplied to the measuring cylinders, at least one air unit bracket (13) to position the valve (15) and the regulator (14), at least one fitting (11) to ensure air connection to the measuring cylinders, at least one controller (3) accommodating items such as display, PLC, buttons, electrical control elements to control the device, at least one measuring body (2) to house the measuring cylinders and the probes (9), and at least one main body (1 ) to support the entire structure.

On the main body (1) supporting the whole structure are a measuring body (2) made of metal with low thermal expansion, and a controller (3). The bushings (4) disposed on the measuring body (2) accommodate the linear movements of the measuring cylinders. The cylinder body (5) is filled with pressurized air, and the cylinder shaft (6) reciprocally moves to actuate the probe holder (10). The probe (9) movably coupled to the probe holder (10) abuts the obstacle it encounters during motion and waits for a while to allow the sensor (7) to obtain a reading. The floating joint connector (8) absorbing axial misalignments between the cylinder shaft (6) and the probe (9) allows correct positioning of the probe (9). Pressurized air connections are provided with fittings (11), the regulator (14) is used to regulate the air pressure and a slidable and single-coil valve (15) is utilized to provide pneumatic movement of the measuring cylinders. The cylinder guard (12) is utilized to protect the measuring assembly from external influences.