KR920004268B1 - Stud welding apparatus with two-wire control - Google Patents

Abstract

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Description

Stud welding device

The schematic diagram of the stud welding system which implements this invention provided with the stud welding tool connected with two control lines, and a remote control apparatus.

* Explanation of symbols for main parts of the drawings

10: welding tool 12: welding control device

16: Chuck 18: Stud

32: welding cable 36: solenoid core

38: coil 48: trigger

50: welding cycle control circuit 52: welding power source

PS: power source SC: low current detection circuit

OPTd: Photosensitive Silicon Controlled Rectifier OPTe: Light Emitting Diode

RD: red light emitting diode GD: green light emitting diode

D1, D2: Shielding Diode U1: Single Junction Transistor

The present invention relates to a stud welding device using only two control leads between a stud welding tool and a remote control device for a welding cycle.

In the drawn arc stud welding technique, a stud with an end welded to the workpiece is generally held by a chuck perpendicular to the workpiece and presses the workpiece. The stud is held by a chuck leg of a stud welding tool with a support leg that carries a welding foot in contact with the workpiece placing a spark or ferrule around the stud. The trigger in the welding tool is pushed close to the start switch and pressed to start a welding cycle that is fully automatic. The solenoid coil in the tool receives the energy and pulls the core into the coil, causing it to retract from the workpiece. At that time, the guide arc is established between the stud and the workpiece and the main welding arc is continuously applied to the guide arc. When energy is lost in the coil, the forward spring retracts the studs from the workpiece, such as a welding arc that is held until the studs contact the workpiece. The molten metal at the stud end and the workpiece is solidified to complete the weld.

Conventionally, four control leads have been used between a remote control device and a welding tool, housed in a suitable container with a power source for the welding arc. Two leads were required between the start switch of the welding tool and the remote control device to initiate the welding cycle, and two leads were needed to effectively move the studs during the welding cycle. The welding cycle must also be run independent of the starting state to ensure that the cycle time is operator independent.

Although a device having two control leads between a welding tool and a welding control device is known in the prior patent, certain stages of the welding cycle in that patent depend on the state of the start switch controlled by the operator. Thus, in US Patent Re-22,310, issued to Mr. Nelson on May 11, 1943, the welding current must remain on until the trigger is released. In US Pat. No. 2,942,096, issued to Mr. Jones on June 21, 1960, the trigger for the start switch must be released before the stud advances to the workpiece. In stud welding cycles controlled by this method, the cycle tends to be long, which is good when the welding cycle is long, but not very good in recent welding cycles, particularly small studs that generally last momentarily. In addition, although a device having two wires has been used in a conventional stud welding tool in which a solenoid coil is placed in series with a welding current cable, this has problems such as heat generation and limited use of welding current. In addition, a device with three wires has been used to a limited extent in direct current devices, but if the wires are connected incorrectly, the damage will be significant.

The present invention provides a two-wire control system between a stud welding tool and a remote control device, wherein the two leads effectively initiate a welding cycle upon closing of the start switch in the welding tool and during the welding cycle regardless of the state of the start switch. Connect tool and remote control to move the stud. The use of only two conductors and the elimination of two additional conductors reduces equipment costs, especially in construction sites where the distance between the tool and the control unit exceeds 30.5 m (100 ft) in some applications. The removal of the two leads also increases the maneuverability of the tool and reduces the cost of repairs if the leads are damaged. Thus, using only two conductors instead of three or four conductors reduces the possibility of improper connection of the conductors by the operator, which may damage the control device.

It is therefore a primary object of the present invention to provide a stud welding device using only two control leads between a stud welding tool and a welding control device to initiate and control a welding cycle.

Another object of the present invention is to provide a two-wire control apparatus for use in a stud welding circuit in which a stud welding cycle is performed regardless of the state of the start switch of the welding tool.

It is another object of the present invention to provide a stud welding system which is inexpensive and reduces the possibility of improperly connecting control leads of the system.

It is a further object of the present invention to provide two control leads for a stud welding system that increase the maneuverability of the stud welding tool and reduce the maintenance.

Other objects and advantages of the present invention will be described in detail with reference to the accompanying drawings by preferred embodiments.

In the figure, the stud welding tool 10 according to the invention lies remote from the welding control device 12. The stud welding tool 10 has a main housing 14 of dielectric material made of several separate components. The chuck 16 is placed at the front end of the tool to hold the studs 18 welded to the workpiece. An appropriate flame screen 22 is placed around the stud 18. The spark shield is placed such that the end of the stud slightly penetrates the back of the spark shield before the end of the stud presses the workpiece so that the stud initially makes good electrical contact with the workpiece. The flame film 22 is positioned and supported as a support foot 24 held in front of the tool by a pair of adjustable legs 26 provided in the housing 14. It is easier to use a mobile ferrule whose permanent flame film is held at a similar position with a suitable support foot according to known techniques.

The chuck 16 is attached to a chuck leg 28 that is electrically connected to the main welding cable 32 with a cable clamp 30. The rear cable clamp portion 34 is attached to the cable clamp 30 and fixes the solenoid core 36. The solenoid core 36 moves in the longitudinal direction of the tool along the cable clamp 30, the cable clamp portion 34, the chuck leg 28, the chuck 16 and the stud 18. The solenoid core 36 rises and extends into the fixed solenoid coil 38 to be advanced back and forth within the coil as power is supplied through the leads 40, 42. The adjustable stop 44 at the rear of the coil 36 determines the degree to which the core retracts into the coil, thus determining the degree to which the studs retract from the workpiece during the welding cycle. The reverse or forward spring 46 reverses the studs in the workpiece after the main welding arc has been established during the cycle time and after the power is shorted to the coil 38.

The stud welding cycle begins when trigger 48 is pressed and continues and completes even if the trigger is released immediately or is maintained after completion of the welding cycle. The welding cycle is controlled by the welding power supplied from the welding power source 52 through the welding cycle control circuit 50, and generally the welding cycle control circuit and the welding power source are one remote from the welding tool 10. Lies in a cabinet The welding power circuit is completed through a ground line 54 in the workpiece and a ground line 56 in the welding power source 52. The accessory components of the welding control device 12 are placed in one module in the cabinet and are electrically connected to the welding cycle control circuit 50.

The distance from the stud welding tool 10 to the welding control device 12 may be considered as greater than 30.5 m (100 ft), for example when the equipment is used in a construction area. Conventionally, four conductors or conductors have been required between the stud welding tool and the welding control device 12 in addition to the main welding cable 32. Two leads were required between the start switch of the tool and the remote control to start the welding cycle, and the two leads needed to transfer power to the solenoid coil 38 to control the movement of the studs during the welding cycle.

The present invention requires only two conductors or leads between the tool and the control device. Only two conductors are used to reduce equipment costs, especially where long conductors are used. Two conductors are removed to make the tool easier to operate with less weight. Damage to the lead is also frequent in applications similar to the construction area, thus reducing maintenance and refurbishment costs. In addition, when only two wires are used, there is less possibility that the wires are inappropriately connected. Facility damage is also reduced.

At the start of the welding cycle, the stud presses on the workpiece until the spark 22 contacts the workpiece. Next, when trigger 48 is pressed, solenoid coil 38 imparts energy to force core 36 back into the coil and removes chuck leg 28, chuck 16 and stud 18 from the workpiece. Let back. The guide arc is established at the time between the stud and the workpiece, and then the main welding arc is applied to the guide arc. The coil 38 loses energy after a predetermined cycle time and the forward spring 46 retracts the core 36, the chuck leg 28, the chuck 16 and the stud 18 from the workpiece. The main welding arc is held when the stud contacts the workpiece. According to this embodiment, the molten metal in the stud and the end and the workpiece remain molten until contacted, at which time the molten metal solidifies to complete the welding.

The overall control system is a low voltage power source (PS) which can be DC if good AC but polarity is indicated and a shield placed on the welding tool 10 and the reaction means in the form of a low current sensing circuit (SC), shown in dotted lines. Diodes D1 and D2 are provided.

When the trigger 48 is pressed, the trigger contacts the start switch 58. The circuit is thereby completed through the limiting resistor R1 and the shielding diode D1 connected from the power source PS through the leads 60 and 62 and from the lead 66 to the leads 64. Conductors 60 and 66 connect only the welding control device 12 and the welding tool 10. The voltage is determined as the capacitor C1 rectified by the diode D3 as a current limited by the resistor R2.

The shielding diode D2 prevents current from flowing through the solenoid coil 38, and the diode D4 prevents the control voltage from coming out of the welding cycle control circuit 50. Zener diode ZD maintains the voltage at capacitor C1 at a safe level.

The voltage across the capacitor C1 is applied across the low current sensing circuit SC. The sensing circuit includes a single junction pulse circuit and an optical pair silicon controlled rectifier. The capacitor C2 in the low current sensing circuit SC is charged through the resistor R3 to the firing point of the single junction transistor U1. When the transistor U1 is turned on, the transistor causes the capacitor C2 to discharge through the light emitting diode OPTe and emits infrared rays. The photosensitive silicon controlled rectifier OPTd, which is packaged in the same way as the light emitting diode OPTe and is a component of the low current sensing circuit SC, operates by detecting the infrared rays. The photosensitive silicon controlled rectifier OPTd is connected to the initiating circuit arrangement of the welding cycle control circuit to start the welding sequence.

At the start of the welding cycle current flows through lead 68 and diode D4 and lead 60 and lead 40 and shield diode D2 and solenoid coil 38. The circuit is completed through the conducting wire 42, the conducting wire 66, and the welding cycle control circuit 50. This embodiment provides a current to actuate the solenoid and raise the stud 18 during the welding cycle. Diode D5 and resistor R4 across coil 38 provide a free-wheeling clamp to protect the control circuitry. Resistor R2 limits the current from the solenoid supply during the welding cycle to protect the power supply PS.

The low current sense circuit SC can be replaced with another low current mandatory relay circuit such as a sensitive relay or solid state switch that can initiate the welding cycle control circuit 50.

When an AC power source is used, the red and green light emitting diodes RD, GD are connected to the welding control device 12 to indicate the state of the electrical installation. Resistor R5 limits the current of the diode. If the circuit is broken, the diode will not work. If the circuit is properly connected, the green diode will work. When the control wires 64 and 66 are reversed, the red diode is activated. When both diodes operate, the orange light appears because the diode is placed in a small container, which indicates a short circuit in the circuit arrangement. Both diodes also operate when trigger 48 is pressed and a welding cycle begins.

Modifications and variations are possible in the above embodiments without departing from the spirit and spirit of the invention.

Claims (14)

A welding tool having a chuck 16 as a means for holding a stud, an electrical solenoid coil 38, a solenoid core 36 connected to the chuck as a stud holding means, a start switch 58, and the solenoid coil Is a stud having a welding cable 32 electrically connected to the chuck, which is a stud holding means, and a process cycle control circuit 50 which is a means for controlling the power supply to the coil independent of the closing time of the start switch. A welding cycle control device remote from the welding tool, a welding power source 52 which is a means for supplying power to the welding cable separately from the solenoid coil so as to form an arc when the stud and the workpiece are spaced apart, and the control means A stur for welding the stud to the workpiece, having a low current sensing circuit SC which is a means of reacting to the closing of the start switch to initiate this welding cycle. A welding device comprising: only two conductors (60,66) for connecting the reaction means to the start switch and the control means to the start switch to connect the reaction means to the control means. A stud welding device according to claim 1, wherein the reaction means is electrically connected in parallel with the control means. A welding tool having a chuck 16 as a means for holding a stud, an electrical solenoid coil 38, a solenoid core 36 connected to the chuck as a stud holding means, a start switch 58, and a stud holding means To form an arc when the stud and the workpiece are spaced apart from the control device remote from the welding tool having a welding cable 32 connected thereto and a welding cycle control circuit 50 that is means for controlling the supply of power to the coil. And a low current sensing circuit (SC), which is a means for responding to the closing of the start switch to cause the control means to initiate a welding cycle. In a stud welding device for welding a stud to a workpiece, the conductor in the welding tool for electrically connecting the contact portion of the start switch and the solenoid coil 38. And means in the conductor means for flowing current only in one direction through the coil and only in the opposite direction through the start switch, and between the conductor means and the reaction means to transfer a control current and a solenoid coil current. A stud welding device, characterized in that it has two conductors connected to it. 4. A stud welding device according to claim 3, wherein the conductor means connects the reaction means parallel to the control means. 4. A stud welding device according to claim 3, wherein the two light emitting diodes are electrically connected in opposite directions at both ends of the lead and effectively indicate three states of the device. 4. The device of claim 3, wherein the first light emitting diode is electrically connected at both ends of the lead in one direction to indicate a state of the device, and the second light emitting diode is opposite at both ends of the lead to indicate the second state of the device. And electrically connected in a direction, said diode effectively executing two light beams to indicate a third state of the device. A welding tool having a chuck 16 as a means for holding a stud, an electrical solenoid coil 38 connected to the chuck as a stud holding means, a start switch 58 and a welding cable 32 electrically connected to the stud holding means And a welding cycle control circuit remote from a stud welding tool having a welding cycle control circuit 50, which is a means for controlling the power supply to the solenoid coil, and a welding cable to form an arc when the stud and the workpiece are spaced apart. A stud welding device having a welding power source 52, which is a means for supplying power, and a low current sensing circuit SC, which is a reaction means in response to closing the start switch to initiate a welding cycle, and welding the stud to the workpiece. A conductor means for electrically connecting the reaction means in parallel with the control means, and a start switch electrically connected to the solenoid coil. Conductor means for connecting current through the coil, conductor means for flowing current only in one direction through the coil and only in the opposite direction through the start switch, conductor means for conveying control current and solenoid coil current; A stud welding device comprising two conductors connected to the reaction means. 8. A stud welding device according to claim 7, wherein the power source is connected in series with the reaction means at both ends of the two conductors. 8. A stud welding device according to claim 7, wherein the reaction means comprises an optical pair silicon controlled rectifier. 8. A stud welding device according to claim 7, wherein the reaction means comprises a single assembly transistor in line with the diode to receive energy when the light emitting diode and the single junction transistor operate. 8. A stud welding device according to claim 7, wherein the reaction means comprises a low current essential relay circuit. 8. The method of claim 7, wherein the first light emitting diode is electrically connected at both ends of the lead in one direction to indicate whether the leads are properly connected, and the second light emitting diode is opposite to indicate whether the leads are improperly connected. And electrically connected at both ends of the conductor in a direction, wherein the two diodes are turned on when there is a short circuit in the welding circuit device. A welding tool having a chuck 16 as a stud holding means, an electrical solenoid coil 38, a solenoid core 36 connected to the chuck as a stud holding means, a start switch 58 and electrically connected to the stud holding means. A welding cycle control circuit remote from the stud welding tool having a welding cable 32 and a welding cycle control circuit 50, which is a means for controlling the supply of power to the coil, between the stud and the workpiece as they are spaced apart. A stud on the workpiece with a welding power source 52, a means of powering the welding cable to form an arc, and a low current sensing circuit SC, a reaction means in response to closing the start switch to initiate a welding cycle. In the stud welding apparatus for welding the welding device, the reaction means is connected to the start switch to connect the reaction means to the control means, and the control means is connected to the start switch. And two light emitting diodes electrically connected across the wire in opposite directions to show three states of the device. A welding tool having a chuck 16 as a stud holding means, an electrical solenoid coil 38, a solenoid core 36 connected to the chuck as a stud holding means, a starter switch 58, and a chuck as a stud holding means. A welding cycle control circuit remote from a stud welding tool having a welding cable 32 connected to the wire and a welding cycle control circuit 50 that is a means for controlling the supply of power to the coil, and when the stud and the workpiece are separated from each other. A workpiece having a welding power source 52, which is a means for powering the welding cable to form an arc in between, and a low current sensing circuit SC, which is a reaction means in response to closing the start switch to initiate a welding cycle. A stud welding device for welding a stud, the apparatus comprising: connecting a reaction means to a start switch and connecting a control means to a start switch to connect the reaction means to a control means; Two lead wires connected to the tooth, a first light emitting diode connected across the lead in one direction to show one state of the device, and a first light diode crossing the lead in an opposite direction to show another state of the device. A stud welding device comprising two light emitting diodes, said light emitting diodes effectively acting on two lights to show a third state of the device.

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