JPH054935Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a claw member for holding a printed circuit board of a carrierless automatic soldering device, and particularly to a resin claw member.

(Prior Art) A carrierless automatic soldering device is equipped with an endless chain that runs oppositely along the frame of the device, and has a large number of claw members (hereinafter simply referred to as "claws") that are engaged with the endless chain. Soldering is carried out by gripping and holding a printed circuit board from both sides using a soldering device (also available), and rotating it over a fluxer, preheater, solder bath, and cooler. Therefore, these claw members are immersed in flux or molten solder together with the printed circuit board. If the claws are made of a metal that can be wetted by solder, the solder will adhere to the claw members metallically, and the solder will gradually build up thickly, interfering with proper holding of the printed circuit board.

Therefore, the claws of automatic soldering equipment have traditionally been made of high-carbon castings, stainless steel, or metal claws whose surfaces are coated with a heat-resistant resin such as polytetrafluoroethylene, to which solder does not easily adhere. . These metal claws are strong, but the casting and cutting process required to make the claws is time-consuming, and the claws are heavy, so if they are attached to the entire chain along an endless chain, the weight will be quite large. Therefore, these conveying devices not only have to be strong in strength, but also have a large amount of power, which increases the cost of devices other than the claws.

In view of the drawbacks of such metal claw members, resin claws have recently been proposed. Utility Model No. 53-63664,
See also No. 61-190359. Resin claws have excellent advantages in that solder does not adhere to them and they are lighter than metal claws, making it possible to reduce the weight of the conveying device and requiring less power to rotate the claws.

However, the resin claws easily break off from the main body after long-term use, resulting in the inconvenience of having to stop the device and replace the claws each time.

Furthermore, a kind of vibration occurs in the pawl member during running, making it impossible to run smoothly. The vibration generated in the claw member is naturally transmitted to the printed circuit board. Since printed circuit boards in recent years are mounted with high density, it is necessary to accurately position the printed circuit board during soldering in order to prevent solder defects and improve the productivity of printed circuit boards. Therefore, the above-mentioned vibration is an important technical problem to be solved because it reduces the productivity of carrierless automatic soldering equipment and increases the cost of printed circuit boards.

(Problem to be solved by the invention) Thus, the purpose of the invention is to reduce breakage of the resin pawl member as much as possible, extend its life, and at the same time reduce the vibration of the pawl member during running. It is an object of the present invention to provide a pawl member that can prevent the soldering from occurring, ensure smooth running, improve soldering accuracy, and improve the yield of printed circuit boards.

When the present inventor investigated the cause of breakage of resin claws, it was found that the resin claws were rubbed and worn out. In other words, when a printed circuit board is soldered using a carrier-less automatic soldering machine, the printed circuit board is heated in the preheater and solder bath, so it thermally expands in the lateral direction, and the claw members holding the printed circuit board become attached to the frame of this machine. begins to impose pressure on Therefore, the claw member runs while the back side is rubbed against the frame, but since resin claws are softer than metal frames, the back side of the claw body that rubs against the frame wears out, making that part weak. It gets old and breaks.

(Means for Solving the Problems) In order to achieve this objective, the inventor of the present invention has conducted various studies and found that, first of all, if the contact between the back surface of the claw body and the frame is surface contact, the entire surface should be However, if it comes into contact with the protrusion provided on the back of the claw body, the sliding movement will be relatively smooth and the minimum sliding performance will be ensured. I found out that this happens.

However, the inventor of the present invention further investigated the problem and discovered that if a resin protrusion was simply provided on the back side of the claw member, the protrusion would wear out quickly (within 2 to 3 months).
It was discovered that it was not practical.

Therefore, the inventor of the present invention made extensive studies to improve the abrasion resistance by applying a metal material to the protrusions provided on the back side of the resin claw member, and as a result, he decided to embed metal pieces in the inner surface of the protrusions. It has been found that by adopting a seemingly simple configuration, not only improvement in wear resistance but also unexpectedly significant improvement in sliding properties between the protrusion and the frame can be achieved. Such an improvement in slidability cannot be achieved by, for example, a configuration in which the entire protrusion is made of metal and a resin is embedded in the inner surface of the protrusion.

In other words, the present inventor has achieved high levels of wear resistance and slidability by embedding a metal piece in the inner surface of the resin protrusion provided on the contact surface of the main body of the claw member with the frame. Knowing that it could be ensured, he completed this idea.

Thus, the present invention provides a claw member for holding a printed circuit board that is attached to an endless chain that runs along a frame of a carrierless automatic soldering device, and includes a locking part that locks to the endless chain, and a locking part that locks the endless chain. It is composed of a main body that hangs down from the main body and has a protrusion on the contact surface with the frame, and a claw tip for holding a printed circuit board provided at the tip of the main body, (i) the claw member is made of resin. and (ii) a claw member for holding a printed circuit board of a carrier-less automatic soldering device, characterized in that it includes a metal piece buried inside the projection made of resin with its surface exposed.

Here, the purpose of the above-mentioned "protrusions" is to make the pinching interval more accurate, that is, to maintain the nail interval accurately, and also to prevent vibrations caused by full-surface contact and enable smooth sliding. Other structures are not particularly limited as long as at least the tip provided on the main body portion is flat on the back surface of the claw member relative to the printed circuit board holding side.

In addition, a metal piece is embedded inside the protrusion so that the sliding surface of the protrusion and its upper surface are on the same plane, reducing the wear of the resin due to contact with the frame as much as possible. There is. The shape of the protrusion is preferably circular, and in that case, the metal piece embedded therein is preferably a concentric annular body. For example, a male thread is formed on a ring-shaped metal piece and screwed into a female thread provided inside the protrusion.

As described above, according to the present invention, since the surface of the metal piece is exposed on the surface of the resin protrusion, wear resistance is improved and significant wear of the resin portion is eliminated. In addition, because a metal piece is embedded inside the contact surface of the resin protrusion, direct contact between the metal piece embedded in the protrusion and the metal of the frame, and the impact of a collision are absorbed by the surroundings. The resin is relaxed and the conformability of both contact surfaces, that is, the sliding properties are improved.

Therefore, according to the present invention, the synergistic effect of improving the wear resistance and sliding property by embedding the metal piece in the inner surface of the resin protrusion is achieved.

(Operation) Next, the present invention will be further explained with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view of a claw according to the present invention. It consists of an upper locking part 3 and a lower claw tip part 4. A female metal screw 5 is embedded in the locking portion 3. This is not limited to screws, but may be any locking means. A protrusion 10 having a flat surface is provided on the back surface of the claw body 2. Although the shape and number of the protrusions 10 are not particularly limited, it is preferable that the protrusions 10 have a circular shape as shown in the illustrated example, and only one protrusion 10 is provided approximately at the center. In terms of area ratio, it is sufficient if it is less than half of the back surface of the nail body. If there are too many, the significance of the protrusion will be lost.

FIG. 2 is an assembled perspective view showing how the claw member is attached to the endless chain, and FIG. 3 is a cross-sectional view when assembled.

In the illustrated example, only one locking portion 3 of the claw member 1 is shown, and is first attached to the endless chain 7. In that case,
The claw member is attached to the endless chain by threading the female screw 5 with the male screw 8 of the endless chain 7 running along the frame. The claw tips 4 for holding the printed circuit board are hook-shaped, and the printed circuit board P is placed on the hook-shaped portion, and the printed circuit board is held between the opposing claw tips.

In the example shown in FIG. 2, a metal piece 9 is embedded in a resin body and installed on the back surface of the main body 2, that is, the part that contacts the frame 6. In the illustrated example, a resin protrusion 10 is provided on the back surface of the main body 1, and a metal piece 9 is embedded in the resin protrusion 10. By installing a metal piece, preferably an annular metal screw, exposed on the surface, wear of the protrusion 10 is reduced as much as possible, and by arranging the metal piece 9 inside the protrusion 10, collisions between metals, The contact is softened by the resin surrounding the metal piece, improving the fit of the protrusion to the frame and improving sliding performance.

When we looked at the service life of a claw member with a resin protrusion and a claw member made of the same resin with a metal piece embedded in the protrusion in an actual soldering device, we found that the former lasted only 2 to 3 months. Previously, the claw member had to be replaced due to wear, but according to the present invention, the claw member equipped with a protrusion embedded with a metal piece does not require replacement even after approximately four years have passed since it was first used. In this invention,
One of the significances of embedding a metal piece within the protrusion is this improvement in wear resistance.

In addition to extending the service life as described above, in this invention, by embedding the metal piece inside the protrusion, direct contact between the metal piece and the frame is eliminated, and the protrusion fits better into the frame. This makes it possible to smoothly transport the claw members that hold the printed circuit board between them, suppressing the generation of vibrations and noise, and enabling quiet operation.

In other words, according to the present invention, when soldering is performed using a carrierless automatic soldering device, the vibration generated in the claw member is suppressed, so the vibration of the printed circuit board during soldering is reduced, and soldering is performed accurately and with high precision. Printed circuit boards can be soldered with high yield.

Such a synergistic effect of the present invention cannot be achieved with other embodiments in which a metal piece is applied to the protrusion, such as an embodiment in which the entire protrusion is made of metal, or an embodiment in which the entire protrusion is made of metal and a resin is embedded inside the protrusion surface. It is not done.

(Effects of the invention) As detailed above, according to the invention, a protrusion with a metal piece embedded is provided in the part where the resin claw member contacts the frame, so that the claw moves toward the frame due to thermal expansion of the printed circuit board. It does not wear easily even if it is pushed and rubbed strongly against the frame, and there is no vibration when running, so it can be used in a stable state for a long time, and the sliding properties between the protrusions and the frame can be further improved. Despite its simple configuration, excellent practical effects can be obtained, and the present invention is of great significance.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a claw member of a carrierless automatic soldering device according to the present invention; FIG.
FIG. 3 is an assembled perspective view illustrating the attachment of the pawl member to the carrier-less automatic soldering device; and FIG. 3 is a schematic cross-sectional view when the pawl member according to the present invention is attached to the carrier-less automatic soldering device. 1... Claw member, 2... Claw body, 3... Locking part,
4...Claw tip, 6...Frame, 7...Endless chain, 9...Metal piece.

Claims (1)

[Scope of Claim for Utility Model Registration] A claw member for holding a printed circuit board that is attached to an endless chain running along a frame of a carrierless automatic soldering device, comprising a locking portion that locks the endless chain, and a locking portion that locks the endless chain. It is composed of a main body part that hangs down from the stop part and has a protrusion on the contact surface with the frame, and a claw tip part for holding a printed circuit board provided at the tip of the main body part, (i) the claw member is made of resin. (ii) A claw member for holding a printed circuit board of a carrier-less automatic soldering device, characterized in that it comprises a metal piece buried inside the projection made of resin with its surface exposed.