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EP-4059650-B1 - HANDHELD WELDING GUN WITH A DISPLACEMENT MEASURING SYSTEM

EP4059650B1EP 4059650 B1EP4059650 B1EP 4059650B1EP-4059650-B1

Inventors

  • Brandl, Björn
  • BRIEL, KARL-HEINZ
  • IVO, HUBERT
  • Jung, Inge
  • Oehlbach, Alexander
  • REICH, THOMAS
  • SCHUG, ALEXANDER
  • SPIESS, Manuel
  • Weber, Kai-Marius

Dates

Publication Date
20260506
Application Date
20210316

Claims (12)

  1. Handheld welding gun (10) for welding an element (22) to a component comprising: - a housing (12) with a main portion (14) and a grip (16) with a trigger (18), the grip extending from the main portion, - a holding unit (20) mounted on the main portion (14) and adapted to movably hold one element (20) between a lift position and a plunge position, - a linear actuator unit (30) with a linear actuator housing (32) and a linear actuator rod (34) adapted to actuate the holding unit (20) in order to move the element (22) between the lift position and the plunge position, the linear actuator rod (34) extending partly inside and partly outside the linear actuator housing (32), - a nozzle (24) surrounding the holding unit (20) and adapted to contact the component, - a welding current contact element arranged in the housing (12) and adapted to direct a welding current to the element (22), the handheld welding gun (10) being characterised by : - a sensor unit (50) adapted to measure different parameters during the welding process, - a processing system (52) with a control card (54) adapted to control one or more parameters of the welding process, - a displacement measuring system (62) communicating with the control card (54), and further characterised in that the linear actuator, the displacement measuring system (62) and the control card (54) are connected together such as to form a compact actuator unit, the displacement measuring system (62) being mounted on the control card (54) and in that the actuator unit is mounted in the main portion at an opposite side of the holding unit.
  2. Handheld welding gun (10) according to claim 1, wherein the displacement measuring system (62) is an optical measuring system and comprises an encoder (64) arranged on the control card (54) and an encoder strip (66).
  3. Handheld welding gun (10) according to claim 2, wherein the encoder strip (66) is fixed to the linear actuator rod (34) through a strip holder and is slidingly movable with regard to the encoder (64).
  4. Handheld welding gun (10) according to claim 2 or 3, wherein the encoder (64) is encapsulated.
  5. Handheld welding gun (10) according to any of claims 1 to 4, wherein the control card (54) is attached to the linear actuator housing (32).
  6. Handheld welding gun (10) according to any of claims 1 to 5, wherein the linear actuator rod (34) is so constructed that it is movable along a longitudinal axis (X) with regard to the linear actuator housing (32) and is secured against rotation around said longitudinal axis (X).
  7. Handheld welding gun (10) according to claim 6, wherein the linear actuator rod (34) is secured against rotation around said longitudinal axis (X) by the linear actuator housing (32).
  8. Handheld welding gun (10) according to any of claims 1 to 7, wherein the linear actuator rod (34) has a non-circular cross-section shape.
  9. Handheld welding gun (10) according to claim 8, wherein the linear actuator rod (34) has an oblong cross-section shape.
  10. Handheld welding gun (10) according to any of claims 1 to 9, wherein the movable parts of the linear actuator are guided within the linear actuator housing (32) by a bearing (40a, 40b), for example a sintered bronze bearing.
  11. Handheld welding gun (10) according to any of claims 1 to 10, wherein a coil body (42) is arranged within the linear actuator housing, and wherein two bearings (40a, 40b) are arranged between the coil body (42) and the linear actuator housing (32), and wherein the first bearing is arranged at a first end of the coil body (42), and the second bearing is arranged at a second end of the linear actuator housing.
  12. Handheld welding gun (10) according to claim 11, wherein the bearings (40a, 40b) are in direct contact with the coil body (42).

Description

The present invention relates to a welding gun, and notably to a handheld welding gun for welding an element to a component according to the preamble of claim 1 (see for example DE 43 14 528 A1). More particularly, the present invention relates to a hand welding device for short-time arc welding of elements, such as metal studs, to parts, such as metal sheets. Welding is a process that has become ubiquitous in various industries for a variety of types of applications. For example, welding is often performed in applications such as shipbuilding, aircraft repair, construction, and so forth. While these welding operations may be automated in certain contexts, there still exists a need for manual welding operations. In short-time arc welding (also known as stud welding) elements such as metal studs are welded onto metal parts such as metal sheets. The studs serve as anchors for various fastening purposes. Accordingly, the studs may be configured as threaded studs (with metric thread), as coarse-threaded studs, pine tree studs, T-studs, etc. In the automotive industry, stud welding has been much used for some years. Here the stud welding technology serves to fasten body parts, to lay electric leads, to fasten carpeting, to weld bolts to car body panels, wherein fixing clips made of plastic are fixed to connect to the bolts, to which fixing clips cables, wires etc. are fixed, etc. A stroke ignition process may especially be used. A metal stud is first placed in the location on the metal sheet where it is to be welded on. Then a so-called pilot current is switched on and the metal stud is lifted somewhat relative to the metal sheet. Thus, an electric arc is set. Then the welding current proper is switched on and the mutually opposed faces are incipiently fused by the high-energy electric arc. Then the metal stud is again lowered onto the metal sheet so that the respective melts will mingle. The arc is short-circuited. The combined melt solidifies and the welding operation is complete. EP1432544A1 from the applicant discloses a known hand held welding gun including an element holder, an electromagnetic actuator operably advancing the holder, and a pneumatic element feeding hose. In some manual welding operations, it may be desirable to monitor weld parameters throughout the welding operation and/or welding gun use before or after the welding operation. While, in automated welding process, the weld parameters may be robotically controlled, parameters like gun motion, damages, ... in a welding operation with a handheld welding gun the welding parameters may depend on the operator's welding technique, the weld pattern and position, the experience of the welding operator, and so forth. Unfortunately, it may be difficult to measure this weld motion during a welding operation due to features of the welding environment, operator considerations, and so forth. It is well-known to use sensors in a welding apparatus in order to monitor weld parameters. US9975196 for instance discloses an inertial measurement unit affixed to an apparatus. The inertial measurement unit is endowed with a tri-axis gyro and a tri-axis accelerometer. US10335883 is directed to a gravity-based weld travel speed sensing system. An orientation sensor is associated with a welding torch and configured to sense a welding torch orientation relative to a direction of gravity. EP3177423 A1 relates to a welding system comprising position detection systems with a controller configured to determine welding parameters during the welding session based on the outputs of the detection systems. In EP3243040, a system for measuring the orientation of a welding torch for a manual arc welding process is disclosed. It is an object of the present invention to specify an improved handheld welding gun adapted to monitor a welding operation but also a welding gun use and behaviour before and after the welding operation. According to a first aspect of the present invention, a handheld welding gun for welding an element to a component is defined in claim 1. Further preferred embodiment of this first aspect of the invention are defined in the dependent claims. The first aspect of the present invention provides a compact handheld welding gun easily operated by a user. The known welding guns comprise several sensors or measurement system in order to improve the welding process. Displacement measurement systems are often arranged in welding guns, as notably disclosed in DE102016108612. However, implementing such systems often leads to cumbersome welding guns, which are not easy to handle. This is therefore also an object of the present disclosure to provide a compact welding gun with very low tolerances for the measuring system. Connecting the control card, the displacement measuring system and the actuator together as defined in claim 1 allows a compact unit, easily mounted within the housing. No further control card is necessary, the displacement measurement system is accurate