JPH0418948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a stud welding apparatus using only two control wires for the welding cycle between the stud welder and a remote control device.

Conventional technology In the drone arc stud welding technology,
Studs that are end-welded to the workpiece are held substantially perpendicular to the workpiece by chucks and are pressed against the workpiece. In addition to chuck legs that hold the stud, stud welders have support legs that support a welding foot that positions a spark shield or ferrule around the stack and in contact with the workpiece. When the welding machine trigger is pulled,
The activation switch closes and a completely automatic welding cycle begins. When the solenoid coil in the welding machine is energized, the wick is retracted into the coil and the chuck pulls the stud away from the workpiece. At that time, a pilot arc is created between the stud and the workpiece, and then the main welding arc is applied above the pilot arc. When the coil is deenergized, the pusher spring forces the stud against the workpiece. Normally, the welding arc is maintained until the stud contacts the workpiece. The weld is then completed when the molten metal on the stud end and workpiece solidifies.

Problems to be Solved by the Invention Conventionally, there are usually four control wires between a welding machine and a control device located away from the welding machine in a suitable box together with a power source for the welding arc. Electric wires have been used. Two electrical wires were required between the activation switch within the welding machine and the remote control to initiate the welding cycle, and two electrical wires were required to move the stud during the welding cycle. Moreover, the welding cycle proceeds independently of the state of the activation switch, and the timing of the welding cycle must be independent of the operator.

Early patents include a connection between the welding machine and the control device.
There are some that list two control wires, but
In those patents, certain steps of the welding cycle were independent of the state of an operator-controlled activation switch. For example, U.S. Reissue Patent No.
In the case of Re-22310 (issued May 11, 1943),
Welding current continues until the trigger is released. In the case of U.S. Pat. No. 2,942,096 (issued June 21, 1960), the activation switch trigger must be released before the stud hits the workpiece. The inherent variable factors of the stud welding cycle controlled as described above may be acceptable for longer welding cycles, but for newer welding cycles,
It is completely useless, especially for smaller studs that usually last a fraction of a second. solenoid·
Early stud welders, in which the coil was in series with the welding current cable, also used two wires, but this had the disadvantages of heat build-up and limiting the welding current that could be used. , has some drawbacks. Additionally, three wires were used to a limited extent for direct current equipment, but if the wires were connected incorrectly, they could be severely damaged.

The present invention provides a two-wire control system between the stud welder and a remotely located controller. Two electrical wires initiate the welding cycle when the start switch on the welding machine is closed, and then connect the welder to a remote control to control the stud operation during the welding cycle, independent of the state of the start switch. Make the move. By using only two wires and thus eliminating two additional wires,
This reduces equipment costs, especially when used in construction sites where the distance between the welding machine and the control equipment is more than 100 feet (30 meters). Additionally, eliminating two wires increases the maneuverability of the welder and also reduces the cost of maintaining the wires in the event of damage. Using only two wires instead of three or four wires reduces the chance that the operator will connect the wires incorrectly.
No damage to control equipment.

In view of the above, it is a first object of the present invention to provide a stud welding machine that initiates and controls a welding cycle using only two wires between the welding machine and a welding control device. .

A second object of the present invention is to provide a two-wire control system that can be used in a stud welding circuit to advance the stud welding cycle independently of the state of the welder's start switch.

A third object of the present invention is to provide a stud welding device that is inexpensive and has less possibility of erroneously connecting the control wires of the device.

A fourth object of the present invention is to provide a two-wire type control device for a stud welding machine that improves the maneuverability of the stud welding machine and has low maintenance costs.

Many other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiments thereof and the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings illustrate a stud welding machine 10 embodying the invention and a remotely located welding control device 12. Welding machine 10 typically includes a main housing 14 of insulating material made of several separate parts.
has. Chuck 1 located at the front end of the welding machine
6 holds the stud 18 which is welded to the workpiece. A suitable spark is placed around the stud 18.
Shield 22 is placed. First, in order to make good electrical contact between the stud and the workpiece, the end of the stud should slightly protrude outside the shield before it is pressed against the workpiece.
The shield is positioned. The shield 22 is mounted on a support foot 2 held at the front of the welder by a pair of adjustable legs 26 attached to the housing 14.
4 is supported and positioned. Rather than a permanent spark shield, a disposable ferrule can be used which is held in a similar position with suitable support feet known in the art.

Stud chuck 16 is attached to chuck leg 28 which is electrically connected to main welding cable 32 by cable clamp 30. A solenoid core 36 is secured to a rear cable clamp portion 34 attached to the clamp 30. Core 36 connects cable clamp 30 and section 3
4. moves in the longitudinal direction of the welding machine with chuck leg 28, chuck 16, and stud 18; core 3
6 extends into a pull and hold solenoid coil 38 and is pulled or retracted into the coil when power is applied through conductors 40,42. An adjustable stop 44 at the rear of the coil 36 defines the extent to which the core retracts into the coil and therefore the stud from the workpiece during the welding cycle. A return spring, pusher spring 46, pushes the stud back into the workpiece after the main welding arc has occurred between the workpiece and the stud for a period of time, and after power to coil 38 has been removed.

A stud welding cycle begins when the trigger is pulled and continues to completion regardless of whether the trigger is immediately released or held until the welding cycle is complete. The welding cycle is controlled via a welding control circuit 50, and welding power is supplied from a welding power source 52. Control circuit 50 and welding power source 52 are typically placed in a single cabinet that is stationary apart from welding machine 10. The welding power circuit is connected to the ground wire 54 in the workpiece.
This can be done by passing the ground wire 56 in the welding power source 52. Additional elements of the welding control device 12 may include one or more components mounted within or on the cabinet.
The welding cycle control circuit 50 can be electrically connected to the welding cycle control circuit 50.

The distance from the welding machine 10 to the control device 12 is, for example, when the device is used at a construction site.
It is expected that it will often exceed 100 feet (30 meters). Conventionally, in addition to the main welding cable 32, four conducting wires or electric wires were required between the welding machine 10 and the welding control device 12. That is, two electrical wires are required between the welding machine and the remote control to initiate the welding cycle, and an additional solenoid coil 3 is required during the welding cycle.
Two electrical wires were required to supply power to the stud 8 and control the movement of the stud.

In the present invention, there are two
Only real conductors, i.e. electric wires, are required. Since only two wires are used, equipment costs are lower, especially if long wires are required. The removal of two electrical wires reduces associated weight and allows the welder to be operated more easily. Damage to the wires is also less severe, especially in construction sites and similar uses, and therefore maintenance and replacement costs are lower.
Moreover, if only two are used, there is less chance of connecting the wires incorrectly, and therefore damage to the equipment is considerably less.

To begin the welding cycle, the stud is pressed against the workpiece until the spark shield 22 contacts the workpiece. Next, when you pull the trigger 48,
Solenoid coil 38 is energized and core 36 is retracted into the coil, pulling chuck leg 28, chuck 16, and stud 18 away from the workpiece. At this time, a pilot arc occurs between the stud and the workpiece, followed by a pilot arc.
The main welding arc is added above the arc. Then, after a predetermined period of time, coil 38 is demagnetized and pusher spring 46 pushes core 36, chuck leg 28, chuck 16, and stud 18 back toward the workpiece. The main welding arc typically lasts until the stud contacts the workpiece. This ensures that the molten metal on the end of the stud and the workpiece remains molten until it makes contact, at which point it
The molten metal solidifies to complete the weld.

The welding control device is arranged in a low voltage power supply PS (preferably alternating current, but direct current of indicated polarity is also acceptable), response means in the form of a small current detection circuit SC shown in dotted lines, and in the welding machine 10. Blocking
It has diodes D1 and D2.

When trigger 48 is pulled, the contacts of activation switch 58 close. This creates a circuit from power supply PS through wires or conductors 60, 62, limiting resistor R1 and blocking diode D1 in wire 64, and wire or conductor 66. The only connections between welding machine 10 and welding control device 12 are electrical wires or conductors 60 and 66. With this circuit, voltage is applied across capacitor C1, rectified by diode D3, and current limited by resistor R2.

Blocking diode D2 prevents current from flowing through solenoid coil 38 and diode D4 blocks weld cycle control circuit 50.
prevents the control voltage from appearing. Zener
Diode ZD fixes the voltage on capacitor C1 at a safe level.

The voltage across the capacitor C1 is applied across the small current detection circuit SC. This circuit SC has a unidirectional pulse circuit and an optically coupled silicon controlled rectifier. Capacitor C2 in circuit SC is charged through resistor R3 to the point at which the discharge of unijunction transistor U1 begins. When transistor U1 becomes conductive, it discharges capacitor C2 through light emitting diode OPTe, causing infrared rays to be emitted for a short period of time. A photosensitive silicon controlled rectifier OPTd, which is actually in the same package as the diode OPTe and forms part of the detection circuit SC, detects this light and conducts. Rectifier OPTd is connected to the start circuit of welding cycle control circuit 50 to start the welding cycle.

When a welding cycle begins, current flows through conductor 68, diode D4, wire or conductor 60, conductor 40, diode D2, and solenoid 38. conductor 42, wire or conductor 66,
A circuit passing through the control circuit 50 is formed. This provides current to activate the solenoid and lift the stud during the welding cycle. Diode D5 and resistor R4 across coil 38 provide a freewheeling clamp to protect the control circuitry. Resistor R2 limits the current from the solenoid power supply during the welding cycle;
Protect the power PS.

The detection circuit SC is another small current request relay circuit,
For example, a sensing relay or solid state switch capable of activating the welding cycle control circuit 50 may be substituted.

When using an AC power source, a red light emitting diode RD and a green light emitting diode GD are connected in the control device 12 to indicate the status of the electrical equipment. Resistor R5 limits the current to these diodes. If there is a break in the circuit, neither diode will light up. If the circuit is connected correctly, the green diode will light up.
If control wires 64 and 66 are reversed, the red diode will illuminate. When both diodes are lit, the light appears orange because they are placed close together in a small container. This indicates that there is a short circuit in the circuit. Both diodes also light up when trigger 48 is pulled and a welding cycle begins.

Various modifications to the embodiments described above will occur to those skilled in the art. It is to be understood that such modifications may be made without departing from the scope of the invention, provided they are within the spirit and spirit of the claims.

[Brief explanation of drawings]

The accompanying drawing is a schematic representation of a stud welding apparatus embodying the invention, having a stud welder and a separate control device interconnected by two control wires. 10... Stud welding machine, 12... Welding control device placed at a distance, 14... Main housing, 16
...chuck, 18 ... stud, 20 ... workpiece, 22 ... spark shield, 24 ... support foot, 26 ... adjustable leg, 28 ... chuck leg, 30 ... cable clamp, 32 ... Main welding cable, 34 ... Rear cable clamp section, 36 ... Solenoid core, 38 ... Solenoid coil, 40, 42 ... Conductor, 44 ... Adjustable stop, 46 ... Return (for extrusion) ) Spring, 48...Trigger, 50...Welding cycle control circuit, 52...Welding power source, 54...Ground wire,
56... Earth wire, 58... Contact, 60, 62,
64, 66, 68...Electric wire (conductor), PS...Low voltage power supply, D1, D2...Blocking diode, R1, R2, R3, R4, R5...Resistor,
C1, C2... Capacitor, D3, D4, D5...
...Diode, ZD...Zener diode,
U1...Single junction transistor, SC...Small current detection circuit, OPTe...Light emitting diode, OPTd...
Photosensitive silicon controlled rectifier, GD...Green light emitting diode, RD...Red light emitting diode.

Claims (1)

[Claims] 1. A welding device having a stud holding means, an electric solenoid coil, a solenoid core connected to the stud holding means, a starting switch, and a welding cable electrically connected to the stud holding means. a welding control circuit for controlling power supply to said coil; means for supplying power to said welding cable for generating an arc between mutually spaced studs and workpieces; a welding control device remote from the welding tool, having means responsive to closing operation of the activation switch to initiate a cycle; The welding control circuit and the starting switch are connected by only two electric wires, and the responding means is connected in parallel to the welding control circuit, and the starting switch is connected in parallel to the solenoid coil. 1. A stud welding device characterized in that it has a conductor means of: 2. The device according to claim 1, further comprising two light emitting diodes connected to the two electric wires in opposite directions to effectively indicate three states of the stud welding device. Device. 3. A first light emitting diode indicating a first state of a stud welding device connected to the electric wire in one direction, and a first light emitting diode of the stud welding device connected to the electric wire in a direction opposite to the first light emitting diode. and a second light emitting diode that indicates the second state of the stud welding apparatus, and both of the light emitting diodes emit light to effectively indicate the third state of the stud welding apparatus. The device described. 4. a welding tool comprising a stud holding means, an electric solenoid coil, a solenoid core connected to the stud holding means, an activation switch, and a welding cable electrically connected to the stud holding means; a welding control circuit for controlling the power supply to the welding cable, means for supplying power to the welding cable to generate an arc between the mutually spaced studs and the workpiece, and for causing the welding control circuit to initiate a welding cycle. a welding control device remote from the welding tool, the welding control device having means for responding to the closing operation of the start switch; and a stud welding apparatus for welding studs to a workpiece by a drone arc method, two electrical wires connecting to an activation switch, and conductor means in the welding tool connecting the activation switch in parallel to the solenoid coil, and connecting the response means to the welding control circuit. A stud welding device characterized by being connected in parallel. 5. The device according to claim 4, further comprising two light emitting diodes connected to the two electric wires in opposite directions to effectively indicate three states of the stud welding device. Device. 6 a first light emitting diode connected to the wire in one direction and indicating a first state of the stud welding device; and a first light emitting diode connected to the wire in an opposite direction from the first state of the stud welding device; 4. The welding device according to claim 4, further comprising a second light emitting diode that indicates the second state, and both of the light emitting diodes emit light to effectively indicate the third state of the welding device. Device.