JPH0242394Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spot welding machine for spot welding a predetermined number of welding points by manual operation by an operator on a workpiece to be welded held in a clamper. .

[Problems that conventional technology and ideas try to solve]

In a spot welding machine, the tip of the spot gun wears out in proportion to the number of dots, so conventionally the time interval between tip polishing was indicated on a so-called kanban to ensure welding quality. In other words, chip polishing is carried out at the operator's discretion based on such instructions, and the number of dots during polishing is not always accurate, and it is also a hassle to change kanban cards depending on the content of the work. Furthermore, another problem with such a spot welding machine is that an inexperienced operator may make a mistake in the number of dots on the workpiece.

In view of these points, it is an object of the present invention to provide a spot welding machine of the type mentioned at the beginning, which can accurately know when to polish a chip and can monitor whether the number of dots applied to each workpiece is correct or incorrect. shall be.

[Means for solving problems]

In order to achieve this objective, the present invention provides a first method for counting spot welding signals, as shown in FIG.
counter 1 and display 2 that displays the counted value
and a second counter 4 which similarly counts the spot welding signal and is reset when the clamper 3 is clamped or unclamped by the operator, and the count value of the second counter is set to a predetermined value when the clamper 3 is operated by the operator. an unclamping restraining circuit 7 that disables the unclamping operation of the clamper 3 when this determining circuit determines that they do not match, and a scoring number determining circuit 5. An alarm device 6 that gives an alarm according to the judgment result of step 5.
It is equipped with

[Effect]

Both counters 1 and 4 count up each time the welding current flows. A counter 1 causes a display 2 to sequentially display the cumulative number of dots of the spot welding machine.
Thereby, when the displayed value reaches a predetermined value, the operator polishes the chip and resets the counter 1. The counter 4 counts the number of dots for each workpiece by being reset when the clamper 3 is clamped or unclamped, and the dot number judgment circuit 5 responds to the unclamping operation to determine whether the number of dots at that time is correct. It is determined whether or not it is, and an "OK" or "NG" signal is sent to the alarm 6 according to the determination result. As a result, the operator can know whether there is a work error by checking whether or not the alarm 6 issues an alarm at the end of welding each workpiece, and furthermore, if they do not match, the unclamp restraint circuit 7 causes the clamper 3 to be unclamped. By disabling the clamping operation, it is possible to ensure that the required number of welding points are welded.

[Example of idea]

In FIG. 2, 10 is a spot gun suspended on a balancer as a hanging tool, and the air cylinder 16 is operated manually to hold the workpiece 15 between the tip tip 13 and the pin 14 as a fulcrum. When the timer time elapses, spot welding current is supplied. A transformer 11 is suspended from a balancer and supplies welding current to the spot gun 10. A current sensor 17 detects a spot welding current and generates a spot welding signal.

20 is a clamper that holds the workpiece 15 to be welded, and a cylinder 21 moves an arm 22 around a pin 23.
By reciprocating and rotating the welding member 15, the workpiece 15 is clamped between the pedestal 24 and the pedestal 24. 26 is the object to be welded 15
A switch 27 operates the cylinder 21 to clamp it, and a switch 27 unclamps it. During welding, the workpiece 15 is clamped as shown in the figure, and the worker 1
Reference numeral 9 indicates a switch 18 of the spot gun 10, which causes the tip end 13 to hold the object 15 to be welded, and causes spot welding current to flow therethrough.

Figure 3 shows the circuitry attached to such a spot welding machine, including a counter 31 that counts the pulsed spot welding signal output from the current sensor 17 for chip polishing management, and a counter 31 that counts the pulsed spot welding signal output from the current sensor 17 and displays the counted value. A display 32 and an alarm 33 that notifies you by light or sound when the count value reaches the value to be polished are provided. Additionally, a counter 35 which similarly counts spot welding signals for monitoring the number of dots and is reset by the operation signal of the switch 26, and a counter 35 which is activated in response to the operation signal of the switch 27 and whose count value at that time is set in advance. A dot count judgment circuit 36 that issues an NG signal if the values do not match; a switch circuit 37 that serves as an unclamp restraint circuit that disables the unclamping operation of the cylinder 21 in response to this NG signal; An alarm 38 that emits light or sound in response, and a display 39 that displays the count value of the counter 35 that counts up sequentially are provided. These display device 32, alarm device 33,
As shown in FIG. 2, the alarm 38 and the display 39 are arranged upward so that the operator 19 can see them.

The operation is as follows.

When the workpiece 15 to be welded is set on the pedestal 24 and the operator 19 operates the switch 26, the workpiece 15 is clamped and the contents of the counter 35 are cleared. Worker 19
Each time the spot welding spot welds a predetermined position of the workpiece 15 with the spot gun 10, the counters 31 and 35 count up. When the worker 19 operates the switch 27 when he/she judges that the work is finished,
The number of dots determining circuit 36 takes in the contents of the counter 35 and determines whether the number of dots is a regular number unique to the workpiece 15 to be welded. If it is normal, no alarm is issued and the next workpiece 15 is set. At this time, by operating the switch 26, the counter 35 starts counting again. During this time, the number of dots can be checked on the display 39 at any time. Moshi Switch 27
If the number of dots is abnormal during operation, the dot number judgment circuit 36 outputs an NG signal and activates the alarm 38, and also opens the switch circuit 37 to cut off the unclamp signal from the switch 27. Unclamping of the workpiece 15 by the cylinder 21 is made impossible. While each workpiece 15 is sequentially welded in this manner, the counter 31 accumulates the number of spot welds, and the number is displayed on the display 32. When the number of points to be polished is reached, the alarm 38 issues a polishing instruction.

[Effect of idea]

As mentioned above, according to the manually operated spot welding machine of the present invention, since the cumulative number of spot welding can be checked on the display, the polishing point can be accurately determined.
It also leads to quality improvement. Additionally, there will be no misunderstandings about the polishing time, and there will be no need to replace kanban cards due to takt fluctuations. Errors in the number of spot welds for each object to be welded are automatically notified, and since the clamper does not unclamp, this also leads to improved quality and suppresses variations in finish due to skill level.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the attached parts of a spot welding machine according to the present invention, Figure 2 is a schematic mechanical configuration diagram of a spot welding machine according to an embodiment of the present invention, and Figure 3 is a circuit diagram thereof. FIG. 10...Spot gun, 20...Clamper, 2
6, 27... switch, 6, 33, 38... alarm, 2, 32, 39... indicator.

Claims (1)

[Scope of Claim for Utility Model Registration] In a spot welding machine for spot welding a predetermined number of welding points manually by an operator on a workpiece to be welded held by a clamper, a first counter for counting spot welding signals; a display device that displays the counted value of this counter; a second counter that similarly counts spot welding signals and that is reset when the clamper is clamped or unclamped by the operator; and the second counter that is reset when the clamper is operated by the operator. a number-of-strikes determining circuit that determines whether the counted value of the counter matches a predetermined value; and if this number-of-strikes determining circuit determines that they do not match, it disables the unclamping operation of the clamper. A spot welding machine comprising an unclamp restraint circuit and an alarm that issues an alarm in accordance with the judgment result of the dot number judgment circuit.