JPH0349429Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a circuit board case, and is applied to, for example, a booster, a modulator, etc. in a video tape recorder set, and has a structure in which the case can be bent from a single plate by providing a connecting plate portion. It is an object of the present invention to provide a circuit board case that can be simplified in configuration.

Generally, in a video tape recorder set, a booster and a modulator each having a circuit board case structure are wired as shown in FIG. In Figure 1,
The booster 1 passes a signal input from an antenna input terminal 2 through a high-pass filter 3, a band-pass filter 4, and an amplifier 5, and then distributes the signal through a distributor 6.
One of the outputs further passes through an amplifier 7, a mixing circuit 8, and a high-pass filter 9, and then outputs a signal from a television output terminal 10 to a television tuner, thereby causing the television to display normal video and audio. The other output of the distributor 6 is supplied via an amplifier 11 to a VTR output terminal 12 to a VTR tuner, and the video and audio signals are recorded on a video tape by a magnetic head.

During video and audio playback, the modulator 13 sends the playback video signal from the tape and magnetic head to the video input terminal 14 and the playback audio signal to the audio input terminal 1.
5 respectively. The video signal is supplied to a mixing circuit 22 via a clamp and amplification circuit 21, and the audio signal is also supplied to the mixing circuit 22 via an amplifier 23 and an FM circuit 24 to be mixed with the video signal. The output of the mixing circuit 22 is balanced amplitude modulated in a balanced amplitude modulation circuit 25 using a reference signal from an oscillation circuit 26 (the frequency of this signal can be varied by a trimmer capacitor 40 described later), and further passed through an amplifier 27. The signal is supplied to the mixing circuit 8 of the booster 1 via the modulator output terminal 28 and the modulator input terminal 29, and thereafter the video and audio signals are reproduced on the television in the same manner as in the above case.

Here, in the conventional video tape recorder set, the booster 1 and the modulator 13
Each of the circuit board cases has a separate circuit board case structure, and in particular, the top surface of the case of the modulator 13 is open.

However, according to this, since the top surface of the case of the modulator 13 is open, a plurality of (usually four)
It is not possible to bend the side plates of the three pieces from a single plate (i.e., after bending the three side plates to a U-shape, it is difficult to bend the last side plate to close the U-shape using a press. ), it was divided into two pieces and the last separate side plate was assembled in the assembly process, but this had the drawbacks of requiring a large number of parts and making the assembly work troublesome.

The present invention eliminates the above-mentioned drawbacks, and embodiments thereof will be described below with reference to the drawings.

FIG. 2 is an overall perspective view of an RF unit to which an embodiment of the circuit board case of the present invention is applied, and FIGS. 3A and 3B are a plan view and a vertical sectional view of the RF unit, respectively. The same parts as in FIG. 1 are given the same reference numerals and their explanations will be omitted.

In FIG. 2, the RF unit 32 has a booster 1' and a modulator 13' integrated into one. The booster 1' includes the booster circuit board 33 in the case 34.
It is covered by the booster case part 34a of
Also, the modulator 13' is connected to the modulator circuit board 3.
5 is enclosed by the modulator case portion 34b of the case 34.

The case 34 is made by press punching a single metal plate as shown in FIG.
f, 34g, and 34h, and in particular, the case side plates 34e, 34f, and 34g are integrally connected by a U-shaped connecting plate 34i, and these are bent as appropriate along the dotted line in the figure. It is box-shaped as shown in Figure 2. The case top surface 34c has an opening 34j, holes 34k, 34l, the shield plate 34d has a punched hole 34m, and a lower end recess 34n, and the side plates 34e to 34h have horizontal holes in the upper and lower positions, respectively. The extending protrusion 34p and the engaging convex portion 34q are formed to protrude outward, respectively, and the side plate portion 34
e, 34g, and 34h each have an inward cut-and-raised portion 34r at an appropriate height position, and the side plate portions 34e and 34g each have a lower end bent portion 34s, and the other side plate portions 34f,
34h is a pair of mounting plate parts 34t (holes 34t-
1), and has a lower end recess 34u and a hole 3 as appropriate.
It has 4v. Further, cutouts 34w are provided at adjacent corners of each side plate 34e to 34h to facilitate die cutting and bending of each side plate 34e to 34h.

Further, the connecting plate portion 34i is connected to the case side plate portion 34.
It is most appropriate to form them at the upper end portions of the holes e, 34f, and 34g (that is, the edge portions of the opening surfaces). This is because the board 38 is attached from the bottom of the case 34, so if the connecting plate 34i is formed at the lower end, the connecting plate 34i will get in the way of the board 3.
This is because it becomes difficult to attach the item 8. In addition, since the case top surface portion 34c and the shield plate portion 34d are also connected at the upper end portions of the case side plate portions 34e, 34f, and 34g, the connecting plate portion 34i is formed at the upper end portion of the case side plate portions 34e, 34f, and 34g. In this case, the structure of the case 34 can be simplified.

Here, the case upper surface part 34c, the shield plate part 3
4d, side plate portion 34h, and both side plate portions 34e, 34
The booster case portion 34a is formed by each right half portion in FIG. 4 of g, and the module is constituted by each left half portion in FIG. Rator case part 34
b is constructed.

In addition, in the above structure, especially the side plate parts 34f and 3 in FIG.
Two rib portions 34t-2 are punched out from the inside of the case and deformed at the fold line portions with each mounting plate portion 34t of 4h.
is formed. Therefore, at the time of the RF unit 32 alone or each mounting plate part 3 of the RF unit 32,
4t to a video tape recorder set board (not shown) and tightening screws using the holes 34t-1, the mounting plate portion 34t is attached to the side plate portions 34f and 34f due to the reinforcing function of the rib portions 34t-2.
The perpendicularity to 34h is stable without being out of order, the configuration is extremely stable, and the assembly work is easy.

The booster circuit board 33 has a first circuit board on the upper surface of the board 36.
Each circuit component 3 that constitutes each circuit 3 to 9, 11 in the figure
7, which is fitted into the booster case part 34a from the bottom of the case until it abuts the three inward cut-and-raised parts 34r.
It is fixed by soldering to g and 34h. Also, a cylindrical antenna input terminal 2 and a television output terminal 10
are attached to the holes 34k and 34l of the case top surface 34c, respectively, and the legs 2a and 10a are attached to the board 3, respectively.
6 and soldered. Similarly, the side plate portion 34
The VTR output terminal 12 is attached to the hole 34v of h and connected to the board 36. Booster 1' is thus completed.

Next, the modulator circuit board 35 is attached to the board 38
A circuit component 39 consisting of each circuit 21 to 27 shown in FIG. 1 is provided on the upper surface of the modulator case portion 34.
The protruding plates provided on the left and right sides of the board 38 in FIG.
d, the side plates 34e, 34f, and 34g are soldered and fixed to complete the modulator 13'. At this time, the modulator side substrate 38 is fixed at a position lower than the booster side substrate 36 by the step size 1, as shown in FIG. 3B. The reason for providing this step is the height level of the mounting base of the antenna input terminal 2 and television output terminal 10 relative to the case top surface 34c.
The height level of the trimmer capacitor 40 on the top surface of the oscillation circuit 26, which is the highest among the modulator circuit components 39 (this height level is eventually regulated to match the height level of the connecting plate portion 34i), is approximately the same height. As a level, as will be described later, the top surfaces of the booster 1' and the modulator 13' can be commonly covered by simply one cover 44,
Antenna input terminal 2 and television output terminal 1
Since the leg portions 2a and 10a of 0 are limited to a certain length to prevent the influence of other signals, the step size l is
It is something that causes

Further, a protruding plate portion protruding from the side plate portion 34f of the modulator side board 38 constitutes a terminal plate portion 38a, and a pair of terminal molds 41, 4 are provided on the upper surface of the terminal plate portion 38a as shown in FIG.
2 is fixed. The terminal mold 41 is for the booster, and the terminals 41a to 41c in FIG. 3A are for the booster power supply, the ground, and empty terminals, respectively, and the terminal mold 42 is for the modulator, and the terminals 42a to 42f in FIG. are for grounding, for modulator power supply, for inputting a reproduced audio signal, for grounding, for inputting a reproduced video signal, and for grounding, respectively.

Also, the punched hole 34m-1 of the shield plate portion 34d,
34m-2, there are feedthrough capacitors 43a and 4, respectively.
3b is inserted and fixed. The feedthrough capacitor 43a is a power supply for the booster 1' connected to the terminal 41b,
Further, both ends of the feedthrough capacitor 43b are connected to the modulator output terminal print and the modulator input terminal print (corresponding to numerals 28 and 29 in FIG. 1, respectively) on the modulator side and booster side boards 38 and 36, respectively. This feedthrough capacitor 43
According to a and 43b, the shield plate portion 34 prevents the oscillation signal of the oscillation circuit 26 from being coupled to the booster 1' side.
It can be effectively prevented in cooperation with d. Also, print 2 of the above terminals to connect the modulator and booster.
Since the feedthrough capacitors 8 and 29 are arranged at positions facing each other on the substrates 38 and 36, the feedthrough capacitors 4
The length of the connecting wire via 3a and 43b is also small, and the structure is simple and the assembly work is easy.
The feedthrough capacitors 43a and 43b are shown in FIG. 3B,
Although it is provided above the substrate 36 of the shield plate 34d, it may be provided in the portion between the substrates 36 and 38 of the shield plate 34d.

44 is the upper cover, and the three holes 44 in FIG.
a, 44b, 44c, and a plurality of tongue pieces 44d bent downward on the four sides, especially four tongue pieces 44d.
4d has an engagement hole 44e. This cover 44
In this case, the holes 44a and 44b are loosely fitted into the antenna input terminal 2 and the television output terminal 10, respectively, on the top surface of the case 34, and the tongue pieces 44d on the four sides are fitted to the outside of the side plate parts 34e to 34h, respectively, to form an upper protrusion. 3
It is attached by riding elastically on 4P. At this time, the lower surface of the cover 44 is connected to the case upper surface portion 34c of the booster 1' and the connecting plate portion 34 of the modulator 13'.
i in common, and the engagement holes 44e of the four tongue pieces 44d elastically engage with the upper engagement protrusions 34q of the side plate parts 34e to 34h, respectively, and are firmly locked. Note that the hole 44c of the cover 44 faces the rotor shaft 40a of the trimmer capacitor 40, and the rotor shaft 40a is inserted by a driver (not shown) through the hole 44c.
The oscillation frequency of the oscillation circuit 26 can be adjusted by adjusting the rotation of the trimmer capacitor 40. However, as described above, since the trimmer capacitor 40 is at the same height level as the connecting plate 34i, the rotor shaft 40
Since point a is close to hole 44c, the above adjustment work is easy.

Reference numeral 45 denotes a lower cover, which has a plurality of tongue pieces 45a bent upward on both sides (having appropriate engagement holes 45b).
and bent plate portions 45c and 45d on the other both sides, respectively.
has. The cover 45 has a tongue piece 45a and bent plate parts 45c and 45d fitted to the outside of the side plate parts 34e to 34h, respectively, to the lower surface of the case 34, and a lower protrusion 34p.
The engagement holes 45d are elastically engaged and locked with the lower engagement protrusions 34q, respectively. The RF unit 32 is thus completed. In addition, in the above unit 32, the booster 1'
The VTR output terminal 12 and the signal input terminal molds 41 and 42 of the modulator 13' are arranged on side plate portions 34h and 34f of the case 34 which are not adjacent to each other so as to be spaced apart from each other so that input signals are not mixed with each other.

According to the RF unit 32, the case portion 34a
The booster 1' inside and the modulator 13' inside the case part 34b constitute a case 34 in which both case parts 34a and 34b are bent from a single metal plate, so they can be arranged side by side in a compact manner. As a result, the overall configuration is simplified, and the man-hours for manufacturing and assembly can be reduced. The reason why the case 34 can be bent from a single plate is mainly due to the provision of a connecting plate portion 34i that connects the side plate portions 34e to 34g, and the side plate portions 34e and 3 on both sides.
4g is common to both the booster and the modulator, and the connecting plate portion 34i also serves as a reinforcing rib, and furthermore, as described above, is brought into contact with the upper cover 44 to ensure good mutual ground potential. Further, the connecting plate portion 34i is not particularly limited to the U-shape, and when the modulator case is used alone, side plate portions may be provided on each of the four sides of the square-shaped connecting plate portion and bent integrally. In addition, when the other case part 34a is integrally provided on one side as in the present application, the above-mentioned U-shape may be used. Since it can be set precisely, various shapes can be easily formed from a single sheet, and the range of applications is extremely wide.

In addition, since openings are formed in the upper parts of the case parts 34a and 34b, when adjusting the electronic components arranged on each circuit board 33 and 35 (adjustment of these electronic components is usually done after assembly). ), this adjustment can be easily performed and maintenance work can also be facilitated.

Next, the structure in which the booster and modulator are attached to a video tape recorder set will be explained by comparing the conventional example and the present invention. FIG. 5 shows a configuration in which a conventional separate booster 1 and modulator 13 are attached to a video tape recorder set 51. The booster 1 is fixed to the inner surface of the rear side plate of the set 51, and the antenna input terminal 2 and the television output terminal 10 protrude rearward. Modulator 1
3 is fixed on a board in the set 51, connected to the booster 1 as appropriate, and further connected to a VTR tuner 52 in the set 51. According to this, in order to readjust the trimmer capacitor 40, it was necessary to disassemble the upper panel of the set 51, which was difficult.

However, according to the RF unit 32 in which the booster and modulator are integrated as in the present application, the sixth
When the set 51 is fixed to the inner surface of the rear plate as shown in the figure and each terminal 2, 10 is projected rearward, the trimmer capacitor 40 can be easily readjusted through the hole in the rear plate, which is extremely convenient.

In the above embodiment, a circuit board case in which two circuit boards, a modulator circuit board and a booster circuit board, are disposed as the circuit board was used as an example. Of course, the present invention can also be applied to a circuit board case and a circuit board case in which three or more circuit boards are arranged.

As described above, according to the circuit board case of the present invention, the entire case can be formed from a single board by bending, simplifying the configuration and reducing the number of assembly steps. Since the opening faces the circuit board, it has the advantage of allowing easy adjustment and maintenance of electronic components disposed on the circuit board.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the circuit configuration of a general booster and modulator, Figure 2 is an overall perspective view of an RF unit to which an embodiment of the circuit board case of the present invention is applied, and Figures 3A and B are RF above respectively
The plan view and longitudinal sectional view of the unit, Figure 4 are above.
Exploded view of the RF unit case, Figures 5 and 6
The figures are perspective views showing a conventional booster and a modulator according to the present invention, respectively, attached to a video tape recorder set. 1, 1'...Booster, 2...Antenna input terminal, 10...Television output terminal, 12...
VTR output terminal, 14...Video input terminal, 15...
... Audio input terminal, 26 ... Oscillation circuit, 28 ... Modulator output terminal, 29 ... Modulator input terminal, 32 ... RF unit, 33 ... Booster circuit board, 34 ... Case, 34a, 34b ...
Case part, 34d... Shield plate part, 34e-3
4h...Side plate part, 34i...Connecting plate part, 34t...
...Mounting plate part, 34t-2...Rib part, 34w...
Notch portion, 35...Modulator circuit board, 36,
38... Board, 37, 39... Circuit parts, 40...
...Trimmer capacitor, 41, 42...Terminal mold, 43a, 43b...Feedthrough capacitor, 44,
45...Cover, 51...Video tape recorder set.

Claims (1)

[Scope of Claim for Utility Model Registration] In a circuit board case in which all circuit boards installed therein are enclosed by a case with an open top, A connecting plate portion extending parallel to the circuit board and integrally connecting the adjacent case side plate portions and integrally connecting the other adjacent case side plate portion and having input/output terminals arranged therein. A shield plate part that is integrated with the case side plate part through the case top part and shields the case by dividing it into two rooms, and a shield plate part that covers the open part of the case. A circuit board case further comprising: a cover that is electrically connected to the connecting plate by coming into contact with the connecting plate in an installed state.