JP3691120B2 - PCB mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printed circuit board mounting structure, and more particularly to a printed circuit board mounting structure that prevents electrostatic spark during active maintenance.
[0002]
In recent years, maintenance in electronic equipment is so-called active maintenance in which only a printed board or a failed printed board is replaced while the apparatus is normally operating. In this case, it is necessary to consider such that other printed boards that are operating normally in the shelf do not malfunction or break due to sparks such as static electricity charged on the printed boards.
[0003]
[Prior art]
FIG. 7 shows a conventional example of a printed board mounting structure used for active maintenance. In this conventional example, the printed board 3 is covered with a shield case 12 that has been subjected to antistatic treatment, thereby preventing sparks due to static electricity during active maintenance.
[0004]
In FIG. 7, reference numeral 1 denotes a shelf holding the back panel 2 on the back surface, and 32 denotes a connector for plug-in connection of the printed board 3 to the back panel 2.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional example, since the printed board 3 is put in the shield case 12, the width of one printed board 3 is increased, and accordingly, the mounting efficiency is lowered and the volume of the entire apparatus is increased. In addition to having the drawbacks, it has the disadvantage of incurring an increase in cost.
[0006]
The present invention has been made to solve the above-described drawbacks, and an object of the present invention is to provide a printed board mounting structure that can reduce the size and cost of the apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the printed board 3 is pressed against the reinforcing bar 20 of the back panel 2 before being connected to the back panel 2, and the printed board is interposed via the reinforcing bar 20. 3 is provided.
[0008]
The reinforcing bar 20 is provided to prevent the back panel 2 from warping due to the insertion force of the printed board 3, and an appropriate means is provided on the surface of the back panel 2, that is, on the connection surface side of the printed board 3. Arranged.
[0009]
The frame ground of the printed board 3 being taken through the reinforcing bar 20 means a state in which the ground line of the printed board 3 is short-circuited to the shelf 1 while the grounding metal 4A is in contact with the reinforcing bar 20. Therefore, the reinforcing bar 20 and the grounding metal 4A are formed of a conductor, and the grounding metal 4A is electrically connected to the ground of the printed board 3, and the reinforcing bar 20 is electrically connected to the shelf 1.
[0010]
Therefore, in the invention of claim 1, when the printed board 3 is mounted in the shelf 1, before the connector 32 on the printed board 3 is plugged into the connector on the back panel 2 or the contact pin 21, First, the grounding metal 4A comes into contact with the reinforcing bar 20 of the back panel 2, and charges such as static electricity on the printed board 3 are released. In the present invention in which the discharge path is formed before mounting on the back panel 2, it is not necessary to put the printed board 3 in the shield case 12, so that the mounting pitch of the printed board 3 can be reduced. The cost can also be reduced.
[0011]
According to the second aspect of the present invention, the printed circuit board 3 includes a grounding metal 4B that presses against the guide rail 10 when the printed circuit board 3 is inserted into the shelf 1 and takes the frame ground of the printed circuit board 3 through the guide rail 10. Added. The guide rail 10 is provided to guide the edge of the printed board 3 to guide the printed board 3 to the connection position in the shelf 1, and press-contacts the guide rail 10 when the printed board 3 is inserted into the shelf 1. In order to do this, the grounding metal 4B is mounted in a state of protruding forward from the insertion side edge of the printed board 3.
[0012]
Therefore, in inserting the printed board 3 into the shelf 1 according to the second aspect of the present invention, first, the grounding metal 4B is pressed against the guide rail 10 and the ground line of the printed board 3 is short-circuited to the shelf 1, so Static electricity is discharged. By connecting the printed board 3 to the frame ground when the shelf 1 of the printed board 3 is inserted, the other grounding metal fitting 4A is in contact with the reinforcing bar 20, that is, the printed board 3 is in the shelf 1. It is reliably prevented that a spark is generated between the adjacent printed circuit boards 3 while moving.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Shows the implementation of the embodiment of the present invention in FIGS. In the figure, reference numeral 1 denotes a shelf having a back panel 2 disposed on the back, which is formed of a conductive material, and shell ducts 11A and 11B for introducing cooling air into the shell are formed at the upper and lower portions thereof. .
[0019]
Reference numeral 20 denotes a long reinforcing rod disposed on the mounting surface side of the printed board 3 to reinforce the back panel 2. Both ends of the reinforcing bar 20 are fixed to a mounting member 13 erected on the side wall of the shelf 1. It spans between the left and right edges of the panel 2 and is fixed to the back panel 2 by a fastening member such as a screw. The reinforcing rod 20 and the attachment member 13 are formed of a conductive material such as a metal material, and are fixed to the shelf 1 formed of the conductive material by appropriate means such as screwing or welding.
[0020]
A guide rail 10 is fixed to the back surface of the upper shelf duct 11A and the upper surface of the lower shelf duct 11B in order to guide the upper and lower edges of the printed board 3 and guide the printed board 3 to a predetermined mounting position. 3 is formed in a U-shaped cross section so that the upper and lower edges of the three can be fitted. The guide rail 10 is made of a metal material such as aluminum, or is imparted with conductivity by metal plating on the surface of a synthetic resin material.
[0021]
On the other hand, the printed board 3 inserted into the shelf 1 and connected to the back panel 2 by plug-in is provided with a front shield plate 30 formed of a conductive material at the tip. The front shield plate 30 is provided to prevent electromagnetic noise from being emitted from the gap between the adjacent printed boards 3, 3..., And is connected to the ground line of the printed board 3 via a fixed terminal 33. . Further, an earth spring 34 is provided at the side edge of the front shield plate 30 to ensure contact with the front shield plate 30 of another adjacent printed board 3.
[0022]
In addition, a connector 32 for connection to the back panel 2 and first and second conductive materials are formed at the rear end of the printed board 3, that is, the edge on the connection side to the back panel 2. The ground metal fittings 4A and 4B are fixed. As shown in FIG. 2B, the first ground metal fitting 4A has a pair of elastic clamping pieces 40, 40. When the printed board 3 is inserted into the shelf 1, the elastic clamping piece 40 reinforces. It is provided at a position where the rod 20 can be clamped. The first grounding metal 4 </ b> A has a fixed piece 41 to the printed board 3, and is connected to the ground line of the printed board 3 through the fixed piece 41.
[0023]
On the other hand, the second ground metal fitting 4B is fixed to the upper and lower ends of the rear end of the printed board 3 in the vertical target posture, and is connected to the ground line of the printed board 3 through a fixing piece 41 to the printed board 3. . The second grounding metal 4 has an elastic piece 42 that protrudes outward from the printed board 3 and presses against the guide rail 10 when inserted into the shelf 1.
[0024]
Therefore, in this embodiment, when the printed board 3 is inserted into the shelf 1, first, the second grounding metal 4 B comes into contact with the guide rail 10, so that the electric charge accumulated on the printed board 3 passes through the guide rail 10. Then, it flows into the shelf 1 side and discharge is performed. Thereafter, when the printed board 3 is further inserted, the first grounding metal 4B is pressed against the reinforcing bar 20 before the connector 32 is fitted to the contact pin 21 of the back panel 2 as shown in FIG. Therefore, the remaining electric charge flows into the shelf 1 via the reinforcing rod 20 and the attachment member 13 and discharge is performed.
[0025]
3 and 4 show reference examples of the present invention. In the following description of the reference example, the same components as those in the above-described embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted.
[0026]
In this reference example , ground guide pins 5 having different cross-sectional shapes for each printed board 3 are projected from the back surface of the front shield plate 30 of the printed board 3. The earth guide pin 5 is a bowl-shaped member formed of a conductive material such as a metal material, and a pointed head 50 for guiding insertion into a guide hole 7 described later is formed at the tip.
[0027]
On the other hand, a guide body 6 is formed in the upper and lower shelf ducts 11A and 11B. The guide body 6 is for guiding the ground guide pin 5 instead of the above-described guide rail 10 to guide the connector 32 of the printed board 3 to the connection area of the back panel 2, as shown in FIG. 4B. The spring bodies 60, 60,... Into which the earth guide pins 5 can be press-fitted are fixed at predetermined intervals, or the spiral springs are fixed to the shell ducts 11A, 11B. As shown in FIG. 4C, the guide body 6 may also be formed with a printed board guide portion 51 that guides the upper and lower ends of the printed board 3 in addition to the guide portion of the ground guide pin 5.
[0028]
Further, a guide hole 7 having a shape that substantially matches the cross-sectional shape of the ground guide pin 5 on the printed board 3 side is formed in the front wall of the shelf duct 11, so that the printed board 3 can be inserted into a position other than a predetermined position. Is prevented.
[0029]
Therefore, in this reference example , when the printed board 3 selected by the guide hole 7 is inserted into the shelf 1, the ground guide pin 5 comes into contact with the guide body 6, and the electric charge on the printed board 3 is charged with the ground guide pin 5, and It flows into the shelf 1 via the guide body 6 and is discharged.
[0030]
5 and 6 show a second reference example of the present invention. In this reference example, a key member 9 having a different cross-sectional shape for each printed board 3 protrudes from the front shield plate 30 of the printed board 3 and the cross-sectional shape matches the front wall of the shelf duct 11. A key insertion opening 90 that permits insertion of only the printed board 3 having the key member 9 is opened, and insertion of the printed board 3 at an incorrect position is prevented. The key member 9 is made of a conductive material, and an insertion portion 31 communicating with an insertion hole 91 formed in the longitudinal direction of the key member 9 is opened at a corresponding portion of the front shield plate 30. .
[0031]
Further, a ground cable 8 is connected to the shelf 1. The ground cable 8 is formed by connecting a plug portion 80 to the tip of the conductive cable 81. By inserting the plug portion 80 into the insertion hole 91 of the key member 9, the ground line of the printed board 3 is connected to the shelf 1. Shorted to
[0032]
Therefore, in this reference example , first, the frame portion of the printed board 3 is taken by inserting the plug portion 80 of the ground cable 8 into the insertion portion 31, and then the printed board 3 is inserted into the shelf 1. During insertion into the printed board 3, erroneous insertion of the printed board 3 is prevented by the key member 9 and the key insertion opening 90.
[0033]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to prevent problems caused by discharge of the printed board without covering the printed board with the shield case.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
2A is a side view of FIG. 1, and FIG. 2A is an overall view, and FIG. 2B is an enlarged view showing a contact state of a ground metal fitting to a reinforcing rod.
FIG. 3 is a diagram showing a reference example of the present invention.
4 is a side view of FIG. 3, in which (a) is an overall view, (b) is an enlarged view of a guide body, and (c) is a view showing a modification of the guide body.
FIG. 5 is a diagram showing a second reference example of the present invention.
6 is a side view of FIG. 5. FIG.
FIG. 7 is a diagram showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shelf 10 Guide rail 11 Shelf duct 2 Back panel 20 Reinforcing bar 3 Printed board 30 Front shield board 31 Insertion part 4 Ground metal fitting 5 Ground guide pin 6 Guide body 7 Guide hole 8 Ground cable 80 Plug part 9 Key member 90 Key insertion hole

Claims (2)

A printed board mounting structure in which a printed board is plugged in to a back panel disposed on the back of the shelf,
A printed board mounting structure in which the printed board is provided with a grounding metal that presses against a reinforcing bar of the back panel before connecting to the back panel and takes a frame ground of the printed board through the reinforcing bar. In the printed circuit board mounting structure according to claim 1,
A printed board mounting structure in which the printed board is provided with a grounding metal that presses against the guide rail when the printed board is inserted into the shelf and takes the frame ground of the printed board through the guide rail.

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