JPH0724000Y2 - Component drop detector - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component drop detecting device for detecting a component drop from a substrate whose front and back are reversed.

[0002]

2. Description of the Related Art In recent printed circuit boards, in order to mount electronic parts at a high density, parts have been mounted on both front and back surfaces of the board. in this way,
In order to mount the components on both sides of the printed circuit board, first, with the substrate facing upward, ordinary lead components are inserted into this surface, and the leads are clinched to temporarily fix the components. Next, the substrate is turned upside down with the back side facing up. Then, a chip component such as a Melf resistor is directly placed on the conductor land portion of the substrate with the back surface facing upward, and soldering is performed on the back surface.

In order to mount the components on the back surface of the board in this way, the board must be inverted (180 °) as in the step shown in, but at this time, it should have been temporarily fixed on the surface of the board. Often, the lead components were not fully temporarily secured (eg, without clinching), and were often dropped from the board. In order to prevent a defective printed circuit board with such a dropped component from entering the market, it is necessary to detect this immediately after the component is dropped from the printed circuit board and find the defective printed circuit board.

As a device for detecting such a component dropout, for example, a component drop detection device as disclosed in Japanese Utility Model Publication No. 2-41920 is known. The component drop detecting device will be described below with reference to FIG. The printed circuit board 1 having the lead component 2 mounted on the front surface A is transported by the transport conveyor 3. After that, when the printed circuit board 1 enters the hole 4a in the reversing device 4, the reversing device 4 detects this and reverses 180 ° while sandwiching the printed circuit board 1 by the hole 4a. Then, when the printed circuit board 1 inverted by 180 ° rides on the carrier conveyor 5, the printed circuit board 1 is naturally separated from the hole 4a by the carrier force of the carrier conveyor 5, and the printed circuit board 1 is carried by the carrier conveyor 5, as shown by. Chip components and the like are mounted on the back surface B of the printed circuit board 1 as in the process. The lead component 2 dropped when the printed circuit board 1 is inverted is guided to a guide 7 provided below the reversing device 4. The guide 7 is provided with an optical sensor 9. The optical sensor 9 includes a light emitting section 91 including a light emitting diode or the like for outputting detection light and a light receiving section 9 for receiving the detection light.
2 and.

When the dropped lead component 2 passes the detection light, the detection light is blocked, so that the light receiving section 92 detects the fall of the lead component 2 by the blocking of the detection light.
The display lamp 6 is turned on to give an alarm. Therefore, it is possible to detect the fall of the lead component 2 when the substrate is turned over, and it is possible to prevent the defective substrate from which the component is dropped from entering the market.

[0006]

However, if the optical sensor 9 is used to detect such a component drop, the following problems will occur. FIG. 4 is a top view of the guide 7 as seen in the vertical direction (the direction indicated by the arrow D in FIG. 3), but as shown in FIG. 4, the detection light is linear, so the detection range is very narrow. Therefore, in order to pass the dropped lead component 2 within this detection range, the guide 7
The diameter of must be reduced. However, if the diameter of the guide 7 is reduced and the guide 7 is narrowed in this way, the lead component 2 may be caught in the guide 7 and stop inside the guide 7. Then, as shown in FIG. 3, when the stopping position of the lead component 2 is above the detection range, the lead component 2 does not pass the detection range as a matter of course, and therefore the lead component 2 falls off the printed circuit board 1. However, this cannot be detected. On the contrary, if the diameter of the guide 7 is increased in order to prevent the lead component 2 from being caught, the ratio of the detection range to the diameter becomes small, and the component 2 falls without passing through the detection range.
As a result, the dropout of the lead component 2 cannot be detected. Further, if an attempt is made to increase the detection range, the light emitting unit 91 and the light receiving unit 92 are required correspondingly, which causes a cost problem.

An object of the present invention is to detect a component drop quickly when the substrate is turned over and to detect the component drop accurately without missing the component drop.

[0008]

In order to solve the above-mentioned problems, the present invention provides a carrying means for carrying a substrate on which a component is mounted, and a reversing means for inverting the board carried by the carrying means. Disposed at least below the position at which the substrate is completely reversed by the reversing means and on the floor surface,
Drop detection means for detecting a drop of a component mounted on the substrate by vibration at the time of the fall, and vibration absorbing means provided between the drop detection means and the floor surface for absorbing the vibration of the floor surface. It is characterized by having and.

[0009]

In the present invention, the optical sensor is not used, but the drop detecting means for detecting the drop of the component by the vibration at the time of the drop is used. Most of the parts fall off when the reversing means completes the reversing of the substrate. In the present invention, the drop detecting means is provided at least below the reversing completion position. When the component falls off from the substrate during reversal, the component falls toward the drop detecting means, and when the component collides with the drop detecting means, the drop detecting means vibrates at this time. Detect the fall. As described above, in the present invention, the drop of the component is detected by the vibration, so that the detection range can be widened and the drop of the component can be detected accurately without overlooking. Therefore, according to the present invention, there is no problem such as missing of parts that occurs due to a narrow detection range such as an optical sensor.
Moreover, since the vibration absorbing means absorbs the vibration of the floor surface due to the operation of the peripheral equipment, the vibration of the fall detecting means itself can be suppressed and the unexpected vibration can be eliminated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a component drop detecting device according to an embodiment of the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals, and the configurations and operations of the transport conveyors 3, 5 and the reversing device 4 have already been described, and thus the description thereof will be omitted. As described with reference to FIG. 3, the board 1 on which the lead component 2 is mounted is reversed by the reversing device 4, but in this example, it is a fall detection means for detecting the fall of the lead component 2 at the time of reversal or after reversal. The drop detector 10 is provided from below the position where the printed circuit board 1 is completely inverted to below the conveyor 5.

The drop detector 10 includes a component receiving portion 11 for directly receiving the fall of the lead component 2, a vibration sensor 12 for detecting a vibration degree of the receiving portion 11, and a vibration sensor 12 for this.
An abutment 13 that supports the spring, a spring 14 provided at the lower portion of the abutment 13, and a base 15 that supports the spring 14 and is in direct contact with the floor surface 16. The component receiving portion 11 is a rectangular shape made of a thin iron plate. FIG. 2 shows a top view seen from the arrow C in FIG. 1 at this time. Also, the vibration sensor 1
2 is composed of a movable portion 121 and a main body 122.
The movable portion 121 is made of a magnetic body that moves vertically in the main body 122, and directly contacts the component receiving portion 11 to support the component receiving portion 11 by magnetic force. A piezoelectric element (not shown) and a detection circuit (not shown) are provided in the main body 122.
The detection circuit in 2 converts the pressing force (strain amount) when the movable portion 121 directly contacts the piezoelectric element into a voltage, and determines whether this voltage (pressing force) is a predetermined value or more.
Therefore, in this example, the movable part 121 is usually the spring 14 described later.
However, when the lead component 2 falls and collides with the component receiving portion 11, the collision of the lead component 2 causes the movable portion 121 together with the component receiving portion 11 to vibrate greatly in the vertical direction. Due to this vibration, a large pressing force is generated in the piezoelectric element, and when the voltage (pressing force) of the main body 122 of the vibration sensor 12 when the movable portion 121 vibrates becomes a predetermined value or more, the lead component 2 causes the component receiving portion 1
It judges that it has fallen to 1 and outputs an alarm signal. In this example, the detection sensitivity is set high so that an alarm signal is output even if the lightest lead component 2 falls.

The spring 14 at the bottom of the abutment 13 absorbs vibrations from the peripheral equipment (for example, the conveyors 3, 5 etc.) transmitted from the floor surface 16 so that the movable portion 121 does not vibrate due to this vibration. It is provided. By doing so, it is possible to prevent erroneous detection of component drop due to vibration from peripheral devices. The drive stopping device 17, which is electrically connected to the vibration sensor 12, stops the driving of the conveyors 3 and 5 when detecting the alarm signal from the vibration sensor 12. Further, the buzzer 18 sounds an alarm when it detects an alarm signal.

Next, the operation of this example will be described. If the lead component 2 falls off the printed circuit board 1 at the time when the printed circuit board 1 reaches the reversal completed position or when the reversed printed circuit board 1 starts to be conveyed by the conveyor 5, the lead component 2 drops to the component receiving portion 11. . Lead parts 2
When the component collides with the component receiving portion 11, the movable portion 121 vibrates. When the voltage (pressing force) of the main body 122 of the vibration sensor 12 during the vibration of the movable portion 121 becomes a predetermined value or more,
It is determined that the lead component 2 has fallen, an alarm signal is output and the buzzer 18 is operated to notify the surrounding workers and the like that the component has fallen, and the defective substrate is prevented from flowing to the next process. The drive stop device 17 is operated to stop the drive of the conveyors 3, 5. After that, if the worker picks up the dropped lead component 2 in the component receiving portion 11 and further takes out the printed circuit board 1 at the inversion completion position, the original work can be started.

As described above, in this example, the defective substrate can be promptly found at the time when the lead component 2 comes off, so that the defective substrate can be prevented from entering the market. Further, in the present example, the component receiving portion 11 is, so to speak, a detection range, so this detection range is extremely wide, and it is possible to detect this accurately without missing a component drop. Therefore, in this example, there is no problem such as missing of parts that occurs due to a narrow detection range such as an optical sensor.

In this example, the component receiving portion 11, that is, the drop detector 10 is provided from below the reversal completion position to below the conveyor, but the present invention is not limited to this, and at least only below the reversal completion position. Even if the component receiving portion 10 is provided within the range, the component drop can be sufficiently detected. Moreover, it is possible to prevent erroneous detection due to vibration from peripheral devices, and it is possible to detect component drop with high accuracy. In particular, when detecting the vibration of a lightweight component, the effect can be more exerted.

[0016]

As described above, according to the present invention, it is possible to detect a component drop quickly when the substrate is turned over, and to accurately detect the component drop without overlooking it.

[Brief description of drawings]

FIG. 1 is a block diagram showing a component drop detection device according to an embodiment of the present invention.

FIG. 2 is a top view of the component drop detection device as seen from the arrow C in FIG.

FIG. 3 is a configuration diagram showing a conventional component drop detection device.

4 is a top view of the guide 7 as seen from the arrow D in FIG.

[Explanation of symbols]

 10 ... Fall detector 11 ... Component receiving part 12 ... Vibration sensor 13 ... Abutment 14 ... Spring 15 ... Base 16 ... Floor

Claims (1)

[Scope of utility model registration request] 1. A carrying means for carrying a board having a component mounted on its surface, a reversing means for reversing the board carried by the carrying means, and at least below a position where the board has been completely reversed by the reversing means. Is provided on the floor surface and is provided between the fall detection means and the floor surface, the fall detection means for detecting the fall of the component mounted on the substrate by the vibration at the time of the fall, and the floor. A component drop detecting device, comprising: a vibration absorbing means for absorbing surface vibration.