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EP-4628240-B1 - RESISTANCE WELDING APPARATUS HAVING A FIXED ELECTRODE AND AN ELECTRODE MOVABLE BETWEEN A WORKING POSITION AND TWO SEPARATE REST POSITIONS

EP4628240B1EP 4628240 B1EP4628240 B1EP 4628240B1EP-4628240-B1

Inventors

  • BOUYGUES, Bruno
  • FRISON, Arnaud
  • GABILLARD, Mickael

Dates

Publication Date
20260513
Application Date
20250219

Claims (5)

  1. Resistance welding device comprising a clamp (1) to support an arm including a first part (1A) supporting a stationary electrode (2) and a second part (1B) supporting a translationally movable electrode (3), the electrodes (2, 3) being configured to be passed through by an electrical current and positioned to clamp metal elements in order to weld them, characterised in that the movable electrode (3) is configured to be movable between: a working position (P0) wherein the electrodes (2, 3) clamp the metal elements to be welded, a first opening position making it possible to insert, between the electrodes (2, 3) disposed opposite one another, the metal elements to be welded wherein the movable electrode (3) is in a first resting position (P1) and located at a first distance (D1) from the stationary electrode (2), a second opening position making it possible to insert, between the electrodes (2, 3) disposed opposite one another, the metal elements to be welded wherein the movable electrode (3) is in a second resting position and located at a second distance (D2) from the stationary electrode (2), greater than the first distance (D1) ; the welding device comprising blocking means which blocks the movable electrode (3) in the first resting position (P1), and actuating means which are designed to act on the blocking means to permit the movement of the movable electrode (3) to the second resting position (P2) under an effect of return means.
  2. Resistance welding device according to claim 1, comprising a cylinder rod (4) whereon the movable electrode (3) to be translationally driven is mounted, the cylinder rod (4) being integral with the return means configured to return the movable electrode (3) from the working position (P0) to the first resting position (P1), then to the second resting position (P2) when the movement is permitted.
  3. Resistance welding device according to claim 2, wherein the blocking means comprises a blocking latch (5) provided with a blocking finger configured to cooperate with a stop (61) arranged on an outer surface of the cylinder rod (4).
  4. Resistance welding device according to claim 3, wherein the blocking latch (5) is mounted pivotable about an axis of rotation (9) between a blocking position wherein the blocking finger cooperates with the stop (61) and a release position wherein the movement of the movable electrode (3) to the second resting position (P2) is permitted.
  5. Resistance welding device according to claim 4, wherein the actuating means includes an unlocking lever (10) configured to actuate pivoting of the blocking latch (5).

Description

Scope of the invention The field of the invention is that of resistance welding devices. The invention relates more particularly to such devices comprising a clamp for supporting an arm consisting of a first part supporting a fixed electrode and a second part supporting a moving electrode (see for example DE8815009 forming the basis of the preamble to claim 1). Prior art and its drawbacks Resistance welding machines generate very strong electric currents that pass through electrodes via electrical contacts within each electrode. The electrodes are designed to grip materials, particularly metallic elements, in order to weld them, creating a weld point. During the welding process, the passage of very high currents between the electrodes heats the materials due to their greater electrical resistance compared to the electrodes. For example, the very high currents passing through the electrodes range from 1,000 A to 15,000 Amperes. Spot welding machines are known to have a unit with a clamp supporting an arm, for example, a C-shaped arm. The arm has two arms: one supporting a fixed electrode and the other supporting a moving electrode. Modern welding machines include an actuator, for example, a pneumatic cylinder. The use of such a pneumatic cylinder allows for the control and application of linear movement to the moving electrode. This linear movement allows, in one direction, the moving electrode to be brought closer to the fixed electrode in order to clamp the materials to be welded in a working position, with the clamp in a closed position. In the opposite direction, the moving electrode to be moved away from the fixed electrode in order to release the materials, with the clamp moving from a closed to an open position. When the clamp is open, locking means secure the moving electrode. in a resting position away from his working position. Typically, the linear movement of the moving electrode from the rest position to the working position is initiated after activation of a control button configured to pressurize a chamber of the pneumatic cylinder. Once the weld point has been made, the moving electrode is configured to move from the working position to the rest position after deactivation of the control button for example, so as to induce a vacuum in the chamber of the pneumatic cylinder which was then under overpressure. One drawback of these resistance welding machines is that the distance between the working position and the resting position of the moving electrode is fixed. Specifically, this distance is predefined and optimized according to the geometries and thicknesses of the materials to be welded. To overcome this drawback, resistance welding machines exist in which this distance can be increased by manually manipulating the moving electrode of the clamp to move it further away from the fixed electrode, i.e., by retracting the moving electrode. For example, the means for locking the moving electrode in its resting position may include a clamping element, such as a clamping ring, against which the moving electrode is held and cannot move further away from the fixed electrode. In particular, the clamping element is designed, firstly, to be manually tightened onto the second part of the arm to hold the moving electrode in its resting position. Secondly, after manually loosening the clamping element, it is possible to directly manipulate the moving electrode, and in particular to move it further away from the fixed electrode before manually tightening it again to hold the moving electrode in a new resting position. However, with such a clamping device, an operator must manually move the moving electrode to change its resting position. Furthermore, the clamping efficiency of such a device inevitably degrades over time, particularly with repeated tightening and loosening cycles. Objectives of the invention The present invention proposes a welding apparatus equipped with a linear motion arm for a spot welding clamp with "C" movement. The welding apparatus has a mechanism which allows, on the one hand, the moving electrode to be moved between the clamping position, i.e. the working position, and the rest position, and on the other hand, the moving electrode from the first rest position to a retraction position located at a distance from the working position greater than the distance separating the working position from the rest position. Furthermore, the movement of the mobile electrode between its rest position and its withdrawal position is achieved without manual manipulation of the mobile electrode. Description of the invention To this end, the invention relates to a resistance welding apparatus comprising a clamp for supporting an arm having a first part supporting a fixed electrode and a second part supporting a moving electrode, the electrodes being intended to carry an electric current and to grip metallic elements for welding, the moving electrode being configured to move between: a working positi