JPH0594786U - Out-of-stock prevention device - Google Patents

Abstract

(57) [Abstract] [Purpose] An out-of-stock prevention device with a simple structure that guarantees a stable out-of-stock detection operation that does not cause detection errors due to the surrounding environment or magnetic field without risk of erroneous detection. Offer of. [Arrangement] A positioning guide pin having an air hole that protrudes from a cylinder portion toward a positioning portion of a component by air pressure and releases the air pressure to the protrusion portion, an air pressure supply means, and an air hole is shielded by the positioning component in a positioned state. And a pneumatic pressure detecting means for detecting a change in the pneumatic pressure generated in the cylinder portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a stockout prevention device, and more particularly, to a stockout prevention device for detecting a presence or absence of a component in positioning a part to prevent a subsequent work from being continued as a stock item.

[0002]

[Prior Art]

 Conventionally, this kind of shortage prevention device has been indispensable in the production process, and when parts to be joined or assembled are to be positioned relative to each other, one main part is preset. If there is no part to be attached to this position and it is automatically transferred to the subsequent process, serious inconvenience may occur. For example, in a positioning device incorporated in an electric resistance welding machine for welding a nut to a set position on the upper surface of a steel plate, a guide pin conventionally attached to the welding machine is used prior to the welding process. The holes in the steel plate are aligned with the holes in the nut. After that, however, a device shown in Fig. 2 has been used as a shortage prevention device to detect the presence or absence of the nut. ..

Here, 100 is a steel plate to which the nut 200 is to be welded, and 100 A and 200 A are pre-drilled holes in the steel plate 100 and the nut 200, for example, fixing holes used for assembly. 2A and 2B, 300 is a vertically movable guide pin having a spindle-shaped tip, and a magnetic coil 400 is provided inside the guide pin 300. By projecting 300 from the lower surface side of the steel plate 100 to the upper side, the hole 100A of the steel plate 100 and the screw hole 200A of the nut 200 are penetrated and both are positioned. At this time, the change of magnetism is detected as a current value by measuring the obtained current value with the meter 500 through the magnetic coil 400 built in the guide pin 300, and the presence or absence of the nut 200 is detected. ..

Besides, for example, as shown in FIGS. 2C and 2D, a magnetic coil 400 is provided above the position of the steel plate 100 to be positioned to detect the presence or absence of the nut 200 on the steel plate 100. Or a photo sensor 600 including a light projecting section 600A and a light receiving section 600B is arranged at a position where the nut 200 is to be positioned as shown in FIG. In some cases, the presence or absence of the nut 200 is detected by a detection means.

[0005]

[Problems to be solved by the device]

 However, in all of the above-mentioned conventional shortage prevention devices, it is necessary to dispose the power supply, wiring device, and electrical inspection parts in the vicinity of the welding machine, and these are used in the welding machine. Large current, or other electrical equipment installed in the factory, or the influence of lightning strikes, which can easily cause erroneous detection. There was a problem such as operation.

The object of the present invention is, in view of such a conventional problem, in order to solve the problem, it is suitable for a positioning device which has no fear of erroneous inspection and which can stably and easily detect a missing item with a simple configuration. It is to provide a shortage prevention device.

[0007]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention has an air hole that projects toward a positioning part along a cylinder part by air pressure, and has an air hole for releasing the air pressure on the projection part, and the projection part is positioned. Positioning guide pins formed corresponding to the shape of the parts, air pressure supply means for supplying the air pressure to the cylinder part, and fluctuations due to the parts blocking the air holes when positioned The air pressure detecting means for detecting the air pressure in the cylinder portion to detect the positioning state of the component is provided.

[0008]

According to the present invention, when the parts to be positioned are correctly positioned, even if the air pressure supplied to the guide pin projecting toward the positioning portion tries to escape from the air hole to the outside. The air pressure in the cylinder chamber is increased because the escape is shielded by the parts. Therefore, it is possible to detect the presence or absence of the positioning component or the positioning failure by the air pressure detecting means depending on whether or not the air pressure is increased.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The present embodiment is an example in which the nut 200 is incorporated in an automatic welding machine that resistance-welds the upper portion of the steel plate 100 at the holed position. That is, in FIG. 1A, reference numeral 1 is a lower electrode member of a welding machine, and the lower electrode member 1 has a stepped cylinder chamber 1A formed therein, and the stepped cylinder chamber 1A is used for positioning. The guide pin 2 is fitted in such a way that it can slide vertically. The guide pin 2 has, as shown in FIG. 1B, a stopper portion 2A having a divergent step at the lower end, and a bottomed air supply passage 2B formed along the axis thereof. Further, it is provided with a nozzle hole 2C for air injection, which penetrates laterally from a bottom portion corresponding to the upper end of the air supply passage 2B. Further, 3 is a socket for supplying compressed air to the cylinder chamber 1A, 4 is a socket to which a detection air pipe 5 for detecting fluctuations in the air pressure in the cylinder chamber 1A is attached, and 6 is air pressure detection means.

In contrast to the lower electrode member 1 as described above, 10 is an upper electrode member, and between the upper electrode member 10 and the lower electrode member 1, the steel plate 100 and the nut 200 to be welded are It is held in the positioned state, and resistance welding is performed by energizing both electrodes from the welding power source 11.

Next, the operation of the thus-configured out-of-stock prevention device that also serves as positioning will be described.

Now, when compressed air is supplied to the cylinder chamber 1 A of the lower electrode member 1 from the air supply source (not shown) via the socket 3, the tip of the guide pin 2 receives the air pressure and the tip portion of the guide pin 2 is a cylinder of the member 1. The chamber 1A is kept protruding upward from the opening 1B. On the other hand, before and after this state, the steel plate 100 is guided to this position manually or by automatic conveying means (not shown), the hole 100A is aligned with the tip of the guide pin 2, and then the tip of the guide pin 2 is positioned. The position of the nut 200 is adjusted by the guide pin 2 by fitting the nut 200 into the.

However, as long as the nut 200 is positioned at a normal position with respect to the steel plate 100 by the above operation, especially when the nut 200 is automatically supplied and positioned, the nut 200 is erroneously misaligned. May not be supplied or may not be properly fitted to the tip of the guide pin 2. In such a case, the compressed air supplied to the cylinder chamber 1A will be ejected from the nozzle hole 2C of the guide pin 2 to the outside with almost no resistance, so that the nut 200 is guided to the guide pin 2 in the air pressure detecting means 6. Detects a significantly lower air pressure than when it was fitted normally. Therefore, by detecting such a change in air pressure, it is possible to detect that the nut 200 is not properly positioned or the nut 200 is missing, and if necessary, change this into an electrical signal, for example. It is possible to display a warning or generate an alarm.

When the nut 200 is properly positioned, air jetted from the nozzle hole 2C of the guide pin 2 collides with the screw hole wall of the nut 200, and the fluid resistance is generated until it comes out of the screw hole 200A. There is little decrease in air pressure in the cylinder chamber 1A. Therefore, the air pressure detecting means 6 can detect this state and give the operator a judgment that the positioning is normally performed.

Therefore, thereafter, for example, the upper electrode member 10 is lowered by a driving unit (not shown), and the nut 200 and the steel plate 100 are sandwiched between the lower electrode member 1 and the welding power source 11 and By energizing between the steel plate 100 and the nut 200, the joint surface can be welded by its resistance heat.

In the embodiment described above, the guide pin 2 is slidably held in the cylinder chamber 1A of the lower electrode member 1 and the guide pin 2 is opened by the air pressure supplied to the cylinder chamber 1A. Although the guide pin 2 is fixed so as to protrude from the lower electrode member 1 in advance, the guide pin 2 for positioning is provided with the hole 100A of the steel plate 100 and the screw hole 200A of the nut 200. It goes without saying that the present invention can be applied to the case where the device is configured to be fitted and positioned one after another.

Further, with the configuration as described above, the welding dust or dust due to the spatter on the steel plate 100 is discharged from the injection hole 2C of the guide pin 2 prior to each feeding operation for positioning the nut 200. Since it is blown away by the jetted air, the effect of keeping the welded part clean can be obtained.

In the embodiment described above, the presence or absence of a member (nut) positioned in a state in which the guide pin 2 provided on the lower electrode member is projected upward by compressed air, and thereby fitted to the protruding portion. Has been detected via an air pressure detecting means for detecting fluctuations in air pressure. However, instead of this, although not particularly shown, a recess having a shape capable of positioning and holding a component such as a nut is provided on the upper surface of the lower electrode member, and a cylinder is formed below the recess. It is also possible to construct a vertically movable guide pin that can be moved upward by negative pressure.

In this case, on the cylinder side, a means for supplying a negative pressure between the cylinder and the guide pin and a means for detecting a change in the negative pressure are connected, and a suction orifice is formed at the top of the guide pin. Whether or not a positioning component such as a nut has been positioned in the above-mentioned recess can be similarly detected by the negative pressure fluctuation detecting means via the guide pin raised by the negative pressure. In this case, the positioning is performed. It suffices to position the part to be welded on the part and then lower the upper electrode member to perform the welding.

[0021]

[Effect of the device]

 As described above, according to the present invention, air pressure is projected toward the positioning portion along the cylinder portion, and the projection portion has the air hole for releasing the air pressure and the projection portion is positioned. A guide pin for positioning formed corresponding to the shape of the component, an air pressure supply means for supplying the air pressure to the cylinder portion, and a variation in the component when the component is positioned to block the air hole. Since the air pressure detection means for detecting the air pressure in the cylinder section to detect the positioning state of the parts is provided, a functional failure occurs due to a strong electric or optical current of the welding machine in the vicinity of the positioning. It is not necessary to provide such a device or component as described above, and it is possible to always detect the presence or absence of a missing item with stable positioning.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an application example of a shortage prevention device of the present invention to a resistance welding machine in a cross section (A) and a detailed cross section (B) of a guide pin of the component.

FIG. 2 shows a configuration of a conventional example, a guide pin type (A), (B) with a built-in electromagnetic coil, and a direct type (C) with an electromagnetic coil,
It is explanatory drawing of the detection operation shown by (D) and an optical sensor type (E).

[Explanation of symbols]

 1 Lower Electrode Member 1A Cylinder Chamber 1B Opening 2 Guide Pin 2A Stopper 2B Air Supply Passage 2C Nozzle Hole 6 Air Pressure Detection Means 10 Upper Electrode Member 11 Welding Power Supply 100 Steel Plate 100A Hole 200 Nut 200A Screw Hole

Claims (1)

[Scope of utility model registration request] 1. An air hole is formed so as to project toward a positioning part along a cylinder part, and the projecting part has an air hole for releasing the air pressure, and is formed in correspondence with the shape of the part on which the projecting part is positioned. The positioning guide pin, the air pressure supply means for supplying the air pressure to the cylinder portion, and the air pressure in the cylinder portion which is fluctuated by the component blocking the air hole when positioned, thereby detecting the air pressure. An out-of-stock prevention device, comprising: an air pressure detecting means for detecting a positioning state of parts.