JPS647225Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic slowing device for an engine-driven welding machine, and more particularly to an automatic slowing device for an engine-driven welding machine that automatically reduces the engine speed when welding is stopped.

In general, engine-driven welding machines have an automatic slowing device that automatically reduces the engine speed when welding is stopped, and immediately turns the engine into high speed when welding starts, in order to prevent noise and save fuel. is often used. Conventionally, as this type of automatic slowing device, one utilizing a plunger solenoid 4 shown in FIG. 1 is known. As shown in FIG. 1, in this automatic speed reduction device, when welding work is stopped, a detection device (not shown) consisting of a current transformer, etc., which detects the presence or absence of welding current, responds to the stoppage of welding work and activates an electromagnetic solenoid 5. to excite,
The plunger 5A is attracted into the electromagnetic solenoid 5. When the plunger 5A is sucked, the connecting rod 6
Pull the upper end 2B of the governor lever 2 toward the low-speed control direction L via the lever. For this reason, the governor lever 2
resists the elastic bias of the return spring 3, swings about the governor shaft 2S as a fulcrum 2A, pulls the governor rod 1 in the direction of arrow A, and rotates the engine at a low speed. On the other hand, when welding is started, a detection device (not shown) detects the welding current and demagnetizes the electromagnetic solenoid 5. Therefore, the governor lever 2 is tilted in the direction of high speed rotation H by the elastic bias of the return spring 3, and pushes out the governor rod 1 in the direction of arrow B, thereby causing the engine to rotate at high speed.

However, the mutual connection between the members 1, 2, 5A, and 6 is such that the plunger 5A, the connecting rod 6, the governor lever 2, and the governor rod 1 are operated smoothly by the energization of the electromagnetic solenoid 5. A certain amount of play is provided between the electromagnetic solenoid 5 and the plunger 5A, and a certain amount of clearance is also provided between the electromagnetic solenoid 5 and the plunger 5A. For this reason, each of the above members 1,
2, 5, 5A, and 6 tend to resonate with engine vibrations, and such resonant vibrations often cause damage to movable parts and connecting parts, resulting in a lack of durability.

In order to solve this problem, the present inventor devised an automatic slowing device using an electromagnet 30, as shown in FIGS. 2 and 3. In the automatic speed reduction device, the governor lever 22 is made of ferromagnetic material. The governor lever 2
2 is a bending portion 2 that can freely swing around the governor shaft 22S as a fulcrum 22A, and faces the electromagnet 30.
The upper end 22 of the tongue piece 22D bent at 2C
It sticks out from B. The electromagnet 30 is attached to the frame of an engine-driven welding machine with a bracket 35, and is attached to a yoke 33.
It consists of an iron core 31 and a coil 32. A gap 3 is formed between the open end 33A of the yoke 33 and the iron core 31.
4, and when the tongue piece 22D is attracted, the iron core 31, the yoke 33, the tongue piece 22D, and the iron core 31
A closed magnetic path is formed leading to the magnet, so that a large attraction force can be obtained with a small excitation current. The electromagnetic solenoid 32 is connected to a detection device that detects the presence or absence of welding current.

When the welding operation is stopped, the welding current will not flow, so the detection device will respond to this and
2 is excited and the tongue piece 22D is attracted to the iron core 31. Such attraction causes the governor lever 22 to swing toward the low speed side L, causing the engine to rotate at a low speed via the governor rod 1. When welding starts, the detection device demagnetizes the coil 32 in response to this, and the governor lever 22 is swung toward the high speed side H by the elastic bias of the return spring 3, and the engine is immediately rotated at high speed via the governor rod 1. Make it.

However, as the automatic slowing device is used, the iron core 31 and tongue piece 22D become magnetized, and after welding is stopped, the welding rod and the welding base metal are short-circuited to start welding, and as a result, the detection device is activated. Even if the coil 32 is demagnetized, the tongue piece 22D does not immediately detach from the iron core 31 due to the magnetic force between the iron core 31 and the tongue piece 22D, and the governor lever 22 moves to the high speed side H after a certain time delay. It may tilt to For this reason, there is a problem that the engine does not rotate at high speed immediately after welding starts, making it difficult to generate arcs.
If the magnetic force magnetized to the iron core 31 and the tongue piece 22 increases, the tongue piece 22D will not separate from the iron core 31 even when the coil 32 is demagnetized, causing a situation where the engine will not rotate at high speed. There is.

Therefore, in view of the above-mentioned circumstances, the present invention has been proposed, even if the engine is automatically slow-speed controlled when welding is stopped by using an electromagnet, the iron core of the electromagnet becomes magnetized as it is used as in the past, and the magnetic force of the magnetization causes the governor lever to move. An object of the present invention is to provide an automatic slowing device for an engine-driven welding machine that can effectively eliminate the problem of switching between a high-speed control position and a low-speed control position becoming slow and eventually not operating. do.

The present invention was made to achieve the above object, and is capable of tilting and is elastically biased in the direction of controlling the engine to the high speed side, and when welding is stopped, the engine is controlled to the low speed side against the elastic bias. In an automatic slowing device for an engine-driven welding machine, which is equipped with a governor lever that tilts in a direction to control the speed, the governor lever is provided with a permanent magnet, and one of its two magnetic poles is oriented in the direction in which the governor lever is to be tilted to a low speed control position. An electromagnet is installed at the low speed control position of the governor lever,
Automatic loosening of engine-driven welding machines, which is arranged opposite to the above permanent magnet, and the electromagnet is connected to a DC power source via a polarity switching relay that responds to the detection signal of a detection device that detects the presence or absence of welding current. It is characterized by a speed device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic slowing device for an engine-driven welding machine according to the present invention will be described below with reference to the drawings. In Figures 4 and 5, Figures 2 and 3
The same parts as those in the figures will be described with the same reference numerals. The governor lever 22 is swingable between a high speed control position H and a low speed control position L using a governor shaft 22S as a fulcrum 22A, like the one shown in FIGS. 2 and 3, and the governor rod 1 is connected to the upper end 22B. and is elastically biased by a return spring 3 in the direction of the high speed control position H. Tongue piece 2 on governor lever 22
The fact that it has 2D is also similar to that shown in FIGS. 2 and 3. A permanent magnet 40 is fixed to the tongue piece 22D. The permanent magnet 40 is attached to the tongue piece 22D with the S pole facing toward the front surface. The electromagnet 30 is placed opposite the permanent magnet 40. The electromagnet 30 is fixed to a frame 47 of the engine-driven welding machine via a bracket 43. The electromagnet 30 has a coil 32 wound around an iron core 31. Coil 32 is connected to DC power supply 41 via polarity switching relay 44 . The polarity switching relay 44 connects the coil 32 with the normally open contact ra _-1 interposed.
One terminal 32a of the coil 32 is connected to the negative electrode of the DC power source 41, and one terminal 32a of the coil 32 and the positive electrode of the DC power source 41 are connected via a normally closed contact rb _-1 . Furthermore, magnetic switching relay 4
4 connects the other terminal 32b of the coil 32 and the positive electrode of the DC power supply 41 through a normally open contact ra _-2 , and connects the other terminal 32b of the coil 32 through a normally closed contact rb _-2 . It is designed to be connected to the negative electrode of the DC power supply 41. A coil 42 that energizes the normally open contacts ra _-1 , ra _-2 and the normally closed contacts rb _-1 , rb _-2 is connected to a detection device 45 that detects the presence or absence of welding current. The detection device 45 is supplied with operating power by a DC power source 49 and has a reed switch 48 interposed in one of the two output lines 46 that supplies welding current to the welding rod and the welding base material. have.

Next, the operation of the automatic slowing device of the engine-driven welding machine having the above configuration will be explained. First, the engine is driven to perform a predetermined warm-up operation. During the warm-up operation, the governor lever 22 is manually positioned at a certain low rotation speed as before. When the warm-up operation is completed, the detection device 45 does not detect the welding current because no welding work is being performed at the time of completion, and therefore the detection device 45 detects the welding current from the coil 42.
The normally open contacts ra _-1 and ra _-2 remain in the demagnetized state.
is maintained in an open state and the normally closed contacts rb _-1 and rb _-2 are maintained in a closed state, and the DC power supply 41 causes the surface of the electromagnet 30 to have a different polarity with respect to the S pole on the surface of the permanent magnet 40, that is, the N pole. Excite it so that Therefore, the electromagnet 30 attracts the permanent magnet 40, thereby tilting the governor lever 22 to the low speed control position L, causing the engine to operate at low speed. Next, to start welding work, short-circuit the welding rod and the welding base material,
A short circuit current flows through the output line 46 and is detected by the detection device 4.
5 detects and energizes the coil 42, which closes the normally open contacts ra _-1 and ra _-2 , and also closes the normally closed contacts rb _-1 and rb _-2.
opens. Therefore, the DC power supply 41 supplies the coil 32 with an excitation current whose positive and negative polarities are opposite to those described above. The polarity of the electromagnet 30 is reversed to become an S pole, which repels the S pole on the surface of the permanent magnet 40. This repulsive force works with the return spring 3 to tilt the governor lever 22 to the high speed control position L, and the engine drive at high speed. During welding work, a welding current flows through the output line 46, so the detection device 45 detects the coil 4.
2 is maintained, the polarity of the electromagnet 30 is also maintained at the S pole, and the governor lever 22 is maintained at the high speed control position H. When the welding operation is stopped, the detection device 45 no longer detects the welding current in the output line 46, so the detection device 45 demagnetizes the coil 42. By demagnetizing the coil 42, the normally open contacts ra _-1 and ra _-2 open, and the normally closed contacts rb _-1 and rb _-2 close, so that the DC power supply 41 has the positive and negative polarities with respect to the coil 32. Provides an excitation current in the opposite direction. Electromagnet 3
0, the polarity is reversed and becomes the N pole, and the permanent magnet 40
The permanent magnet 4 has a different polarity from the S pole on the surface of the permanent magnet 4.
Adsorbs 0. Therefore, the governor lever 22 is tilted to the low speed control position L to operate the engine at low speed. Thereafter, the above operation is repeated every time welding work and every time welding is stopped.

``Effects of the invention'' As described above, according to the automatic slowing device for an engine-driven welding machine according to the present invention, even if the engine is automatically slowed down using an electromagnet when welding is stopped, it will not work like the conventional one. No problems occur due to the use of electromagnets. In other words, as it is used, the iron core of the electromagnet becomes magnetized, and the switching operation of the governor lever between the high-speed control position and the low-speed control position becomes slow due to the magnetic force of the magnetization, and eventually the electromagnet and the governor lever are attracted to each other by the magnetic force of the magnetization. This effectively eliminates the problem of not being able to control the automatic slow speed due to the condition of the governor lever being in the same position, and the responsiveness of the switching operation between the high-speed control position and the low-speed control position of the governor lever is excellent, making it easy to use. It's extremely convenient.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the main parts of an automatic slowing device for a conventional engine-driven welding machine, Figure 2 is a configuration diagram of the main parts of an automatic slowing device that uses an electromagnet, and Figure 3 is a perspective view of the main parts of an automatic slowing device of a conventional engine-driven welding machine. FIG. 4 is a perspective view of the main parts of the automatic speed reduction device of the engine-driven welding machine according to the present invention, and FIG. 5 is a perspective view of the main parts of the automatic speed reduction device of FIG. 4. be. 3... Return spring, 22... Governor lever, 30... Electromagnet, 40... Permanent magnet, 41
...DC power supply, 44...Polarity switching relay.

Claims (1)

[Scope of utility model registration request] An engine-driven welding machine equipped with a governor lever that is freely tiltable and elastically biased in a direction to control the engine to a high speed side, and tilts in a direction to control the engine to a low speed side against the elastic bias when welding is stopped. In the automatic speed reduction device, a permanent magnet is provided on the governor lever, one of the two magnetic poles thereof is oriented in a direction in which the governor lever is to be tilted to a low speed control position, and an electromagnet is provided at the low speed control position of the governor lever, and an electromagnet is provided in the low speed control position of the governor lever. An automatic engine-driven welding machine characterized in that the electromagnets are arranged facing each other and connected to a DC power source via a magnetic switching relay that responds to a detection signal from a detection device that detects the presence or absence of welding current. slow speed device.