WELDING EQUIPMENT AND PROCEDURES

Description

Technical area

[0001] The invention relates generally to a device and a method for fastening a bolt to a substrate (see, for example, US 2 491 479 A). State of the art

[0002] Numerous devices and methods are known for attaching various bolts to a substrate for various applications. For example, a bolt is brought into contact with the substrate and subjected to an electric current. As soon as the electric current flows between the bolt and the substrate, the bolt is lifted from the substrate, forming an arc. The released energy causes the material of the bolt and the substrate to partially liquefy. The electric current is then switched off, and the bolt is immersed in the liquefied material, while this material cools and solidifies. The bolt is then firmly bonded to the substrate.

[0003] To provide the necessary energy to liquefy the material of the bolt and the substrate in a sufficiently short time, devices are known that generate a very high-intensity electric current and supply it to the bolt via an appropriately dimensioned electrical cable. To prevent oxidation of the liquefied material, it is known to purge the contact point between the bolt and the substrate with an inert gas.

[0004] In applications such as building or ship construction, bolts of various sizes with a thread are used, into which an object is screwed to fasten the object to the substrate. Some parameters of the fastening process, such as the duration and electrical power of the electrical current, must be adjusted by the user on the device and adapted to the bolt used. Finally, the user assesses the quality of the connection between the bolt and the substrate through a visual inspection. The quality of the connection therefore also depends on the user's experience and skills. Description of the invention

[0005] The object of the invention is to provide a device and / or a method with which the fastening of a bolt to a substrate is simplified and / or improved.

[0006] This object is achieved in a device for welding welding studs to a substrate, with a welding gun which comprises a stud holder for each welding stud, with a welding device, with a gas container, with a gas line for conducting gas from the gas container to the stud holder, with a valve arranged in the gas line, and with a control device for controlling the valve, which is intended to open the valve during a predetermined period of time before the start of a welding process in order to automatically purge the gas line with gas from the gas container when the device is switched on and / or after a standstill period of the device.

[0007] Automated purging of the gas line may reduce the waiting time before a welding process and / or gas consumption.

[0008] An advantageous embodiment is characterized in that the control device is designed to initiate a welding process when the predetermined period of time has elapsed. An alternative embodiment is characterized in that the control device is designed to signal to a user of the device that the device is ready for a welding process when the predetermined period of time has elapsed.

[0009] A further advantageous embodiment is characterized in that the gas container is carried by the welding device, the gas line and / or the welding gun.

[0010] A further advantageous embodiment is characterized in that the device comprises a gas flow control device for controlling a gas flow through the gas line, wherein the gas flow control device comprises the valve.

[0011] A further advantageous embodiment is characterized in that the device comprises a first electrical cable for conducting welding current from the welding device to the welding gun and a second electrical cable for conducting the welding current from the substrate to the welding device.

[0012] The object is also achieved in a method for welding a welding stud to a substrate, in which a device is provided with a welding gun, which comprises a stud holder for the welding stud, with a welding device, with a gas container, with a gas line for conducting gas from the gas container to the stud holder, and with a valve arranged in the gas line, wherein the valve is opened for a predetermined period of time in order to flush the gas line with gas from the gas container, and the welding stud is welded to the substrate while gas from the gas container flows around the welding stud.

[0013] An advantageous embodiment is characterized in that the welding of the welding stud to the substrate is initiated when the predetermined time period has elapsed. An alternative embodiment is characterized in that a user of the device is signaled that the device is ready for a welding process when the predetermined time period has elapsed. Examples of implementation

[0014] The invention is explained in more detail below using exemplary embodiments with reference to the drawings. It shows: Fig. 1 schematically shows a welding device.

[0015] In Fig. 1A welding device 10 for welding a welding stud 20 to a substrate 30 is schematically shown. A material of the welding stud 20 and a material of the substrate 30 are electrically conductive, in particular metallic. The welding device 10 comprises a welding gun 40 with a trigger switch 41 designed as a push-button switch, a welding device 50 with a housing 51, a first electrical cable 61, a second electrical cable 62 with a connection terminal 63, an electrical supply cable 64 designed, for example, as a power cable, an electrical communication line 65, a gas container 70 designed as a gas can or gas cylinder, and a gas line 72 designed as a gas hose.

[0016] The first cable 61 serves to supply the welding stud 20 with electrical current via the welding device 50. The second cable 62 serves to electrically connect the base 30 to the welding device 50 when the connecting terminal 63 is clamped to the base 30. When the welding stud 20 comes into contact with the base 30, an electrical circuit is closed, so that the welding stud 20 can be subjected to welding current from the welding device 50, which can be, for example, direct current or alternating current. For this purpose, the welding gun 40 comprises a Fig. 1Welding current contact element (not shown). The welding device 50 includes a device (not shown) for converting electrical current from the supply cable 64 into welding current, which includes, for example, an electrical capacitor, a thyristor, an insulated-gate bipolar transistor, or other power electronic components, as well as an associated control unit with a microprocessor to provide the welding current with the desired voltage and current.

[0017] The welding device 50 has an input device 51 with actuating elements 52 and an output device 53 with a visual display element 54 and a wireless transmission unit. The input device 51 serves to allow a user of the welding device 10 to input parameters of a welding process to be performed with the welding device 10, such as the electrical voltage, current intensity, power and duration of the welding current, the position and speed of the stud, and so on.The output device 53 serves to output information, such as information about parameters of the welding process, information about recorded emissions of the welding process or other variables, information about a quality of the welding process, information about measures to improve the welding process, information about recorded properties of the welding stud or information derived from the aforementioned variables, and / or recommendations or instructions for cleaning and / or maintenance of the welding device 10, in particular the welding gun 40, to the user.

[0018] The communication line 65 is used for communication between the welding gun 40, in particular a Fig. 1not shown control device of the welding gun 40, and the welding device 50, in particular the control device and / or the input device 51 and / or the output device 53. This communication, for example, accomplishes an exchange of information about the parameters of a welding process in order to achieve or facilitate, for example, a synchronization of the welding current with a movement of the welding stud 20. In embodiments not shown, the communication between the welding gun and the welding device occurs wirelessly, by radio, or by means of the first electrical cable that carries the welding current.

[0019] The welding gun 40 has a housing 42 with a mouth 46, from which a handle 43 with the trigger switch 41 protrudes. The welding gun 40 further has a stud holder 44, on which the welding stud 20 is held during a welding process. For this purpose, the stud holder comprises, for example, two, three, four, or more resilient arms (not shown in detail), between which the welding stud 20 is inserted and held by a clamp fit. The welding gun 40 further has a welding current contact element for applying a welding current to the welding stud 20, which is integrated into the stud holder 44, for example in the form of one or more of the resilient arms.

[0020] The welding gun 40 further includes a control device 99 for controlling the various components and devices of the welding gun and the welding device 50. The control device 99 is provided for controlling one or more parameters of the welding process. For this purpose, the control device 99 comprises various electronic components, such as one or more microprocessors, one or more temporary or permanent data memories, and the like.

[0021] The welding gun 40 further comprises a stud lifting device designed as a first lifting magnet, which moves the stud holder 44 with a force away from the muzzle 46 to the rear (in Fig. 1 upwards) when the bolt lifting device is activated. The control device 99 communicates with the bolt lifting device via a signal line (not shown) in order to control the bolt lifting device, in particular to activate and deactivate it.

[0022] The welding gun 40 further comprises a stud insertion device designed as a spring element or as a second lifting magnet, which pushes the stud holder 44 forwards (in Fig. 1 downwards) when the stud insertion device is activated. The control device 99 communicates with the stud insertion device via a signal line (not shown) in order to control the stud insertion device, in particular to activate and deactivate it. If the stud insertion device is designed as a spring element, this spring element is preferably tensioned when the stud holder is moved rearward by the stud lifting device, so that the spring element moves the stud holder forward as soon as the stud lifting device is deactivated.

[0023] The gas line 72 serves to supply a contact area between the welding stud 20 and the substrate 30 with a shielding gas from the gas container 70 to protect the contact area from oxidation by ambient oxygen during a welding process. The gas line 72 conducts the shielding gas to the stud holder 44.

[0024] The welding device 50 has a gas container receptacle 73 arranged in the housing 51, in which the gas container 70 is exchangeably received, so that the gas container 70 is carried by the welding device 50. In an embodiment not shown, the gas container is attached, in particular fastened, to the outside of the welding device, for example, to its housing. The gas line 72 has a gas connection element 74, which is arranged on the gas container receptacle 73 for connecting the gas container 70 to the gas line 72.Furthermore, the welding device 10, and in particular the welding device 50, has a gas flow control device 75 designed as a valve, in particular a solenoid valve, for controlling a gas flow through the gas line 72. The gas flow is controlled, for example, by adjusting a cross-sectional area of ​​the gas flow control device 75 or by adjusting a duration or frequency of one or more open phases of the gas flow control device 75. The control of the gas flow is preferably coordinated with the other parameters of the welding process and / or the gas volume in the gas line 72.

[0025] The gas flow control device 75 is arranged entirely within the housing 51 and carried by the welding device 50 and serves to control a gas flow to the contact area between the welding stud 20 and the substrate 30. The gas flow control device 75 comprises a controllable valve, which is controlled, for example, by the control device 99. Among other things, the control device 99 is provided to open the valve during a predetermined period of time in order to purge the gas line 72 with gas from the gas container and initiate a welding process or to signal to a user of the welding device 10 that the welding device 10 is ready for a welding process when the predetermined period of time has elapsed. The automated purging of the gas line 72 may reduce the waiting time before a welding process and / or gas consumption.Furthermore, the welding device 10, and in particular the welding device 50, has a fill level detection device 76 for the gas container 70. The fill level detection device 76 is preferably arranged entirely within the housing 51 and carried by the welding device 50. The fill level detection device 76 comprises a pressure sensor arranged in the gas line 72, for example, on the gas connection element 74, for measuring the internal pressure of the gas container, as well as a data processing device that detects the number of welds performed. In embodiments not shown, the fill level detection device comprises a sensor, in particular for measuring the weight or inertia of the gas container, the pressure or temperature gradient during gas flow control, an acoustic response of the gas container contents, or the like.Additionally or alternatively, the fill level detection device 76 comprises a storage medium which is attached to the gas container 70, and a data processing device which is carried by the welding device and is suitable for storing information about a fill level of the gas container 70 on the storage medium and / or reading it from the memory and / or outputting it by means of the output device 53, for example its display element 54.

[0026] In a welding process using the welding device 10, the substrate 30 and the stud 20 are first provided. In a further step, a user enters information via the input device, for example, information about desired parameters of the subsequent welding process. In a further step, the welding stud 20 is subjected to a welding current between the welding stud 20 and the substrate 30 by the welding device 50 using the first cable 61 and the second cable 62. In a further step, the welding stud 20 is lifted from the substrate by the stud lifting device while maintaining the welding current flowing between the welding stud 20 and the substrate 30, whereby an arc forms between the welding stud 20 and the substrate 30.In particular, due to the heat generated by the arc, a material of the welding stud 20 and / or the substrate 30 is then partially liquefied. In a further step, the welding stud 20 is immersed into the liquefied material of the welding stud 20 or the substrate 30 by means of the stud immersion device. The liquefied material of the welding stud 20 or the substrate 30 then solidifies, so that the welding stud 20 is firmly bonded to the substrate 30.

[0027] To purge the gas line 72 with gas from the gas container 70, the valve of the gas flow control device 75 is opened for a predetermined period of time, and the welding stud 20 is welded to the substrate 30 while gas from the gas container 70 flows around the welding stud 20. Welding of the welding stud 20 to the substrate 30 is initiated when the predetermined period of time has elapsed. Alternatively, a user of the welding device 10 is signaled that the device is ready for a welding process when the predetermined period of time has elapsed. This automatic purging of the gas line is preferably always performed, in particular only when the welding device 10 is switched on and / or after a prolonged downtime and / or after replacing parts of the gas line 72.

[0028] The individual process steps are controlled by the control device 99, which, in particular, also regulates the parameters of the welding process, such as an electrical voltage, a current intensity, and a duration of the welding current, or a time and speed of the bolt movement, or a bolt position, or a gas flow through the gas line 72. Furthermore, the fill level of the gas container 70 and the number of welds performed are detected, stored, and output.

[0029] The invention has been described using examples of a device for fastening a first object to a second object, as well as a manufacturing method for such a device. The features of the described embodiments can also be combined with one another as desired within a single fastening device or a single manufacturing method. It should be noted that the device and method according to the invention are also suitable for other purposes.

Claims

1. Device (10) for welding welding studs (20) to a substrate (30), with a welding gun (40), which comprises a stud holder (44) for a respective welding stud (20), with a welding unit (50), with a gas container (70), with a gas line (72) for conducting gas from the gas container (70) to the stud holder (44), with a valve arranged in the gas line (72), and with a control device (99) for controlling the valve, characterized in that the control device (99) is intended to open the valve only for a predetermined period of time before the start of a welding operation in order to automatically flush the gas line (72) with gas from the gas container (70) when the device (10) is switched on and / or after a downtime of the device (10).

2. Device according to Claim 1, wherein the control device (99) is intended to initiate a welding operation when the predetermined period of time has elapsed.

3. Device according to Claim 1, wherein the control device (99) is intended to signal to a user of the device (10) that the device (10) is ready for a welding operation when the predetermined period of time has elapsed.

4. Device according to one of the preceding claims, wherein the gas container (70) is carried by the welding unit (50), the gas line (72) and / or the welding gun (40).

5. Device according to one of the preceding claims, further comprising a gas flow control device (75) for controlling a gas flow through the gas line (72), the gas flow control device (75) comprising the valve.

6. Device according to one of the preceding claims, further comprising a first electrical cable (61) for conducting welding current from the welding unit (50) to the welding gun (40) and a second electrical cable (62) for conducting the welding current from the substrate (30) to the welding unit.

7. Method for welding welding studs (20) to a substrate (30), with the steps of a) providing a device (10) with a welding gun (40), which comprises a stud holder (44) for a respective welding stud (20), with a welding unit, with a gas container (70), with a gas line (72) for conducting gas from the gas container (70) to the stud holder, and with a valve arranged in the gas line (72), b) opening the valve for a predetermined period of time to automatically flush the gas line (72) with gas from the gas container (70) and c) welding the respective welding stud (20) to the substrate (30) while gas from the gas container (70) is flowing around the respective welding stud (20), characterized in that in step b) the valve is opened only for the predetermined period of time before the start of the welding operation when the device (10) is switched on and / or after a downtime of the device (10) and / or after parts of the gas line (72) have been exchanged.

8. Method according to Claim 7, in which step c) is initiated when the predetermined period of time has elapsed.

9. Method according to Claim 7, in which a user of the device (10) is signaled that the device (10) is ready for a welding operation when the predetermined period of time has elapsed.