JPH0540993U - Fire alarm printed circuit board - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a printed circuit board of a fire alarm device having good noise characteristics and eliminating warpage due to thermal expansion. Constituting a printed circuit board 7 in which an electric circuit is formed by mounting an electric component 7a and the like on one side in a housing 1, and a conductive pattern having a relatively large area formed on the printed circuit board 7. The slit 7c is formed in 7b.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed circuit board of a fire alarm device such as a fire receiver, an interlocking operation panel or a fire detector.

[0002]

[Prior Art]

 FIG. 3 is an exploded perspective view showing an example of a door portion of a conventional fire receiver. In the figure, 31 is a door made of a metal plate which is attached to a main body (not shown) via a hinge so as to be openable and closable, and a square window hole 33 is provided slightly above the central portion of the front plate 32. There is. Reference numerals 34a and 34b denote printed circuit boards, on both surfaces of which wiring patterns are formed and electronic components and the like are mounted. Reference numeral 35 is a display plate having an L-shaped cross section made of a metal plate provided with a large number of display windows, and 36 is a switch plate provided with a large number of switches, etc., and printed on the back surface of the display plate 35 and the switch plate 36 with screws. The boards 34a and 34b are fixed and connected to a printed board or the like provided in the main body. Such a fire receiver gives an alarm when a fire occurs and turns on the indicator light of the area on the display board 35.

[0003]

[Problems to be solved by the device]

 The printed circuit boards 34a, 34b of the conventional fire receiver configured as described above have wiring patterns formed on both sides and electronic components are mounted on the printed circuit boards 34a, 34b. When the 34b is attached, a tool or the like may come into contact with an electric component, or the wiring pattern may be damaged to cause a short circuit, which makes the printed circuit board inconvenient to handle. Moreover, in order to prevent the contact of the printed board and the short circuit of the pattern, the insulating paper is arranged on the back surface of the printed board, which causes a cost increase.

Therefore, in order to solve such a problem, it is conceivable to use a single-sided mounting type printed circuit board A that does not require insulating paper and is easy to handle. The printed circuit board A thus configured has a conductive pattern (hereinafter, referred to as a solid wiring) in which a power source line or the like is formed in a large area in order to make an electric component B such as an IC less susceptible to noise. It is necessary to increase the number of patterns).

However, in the manufacturing process of the printed circuit board A, when the cream solder attached to the printed circuit board A on which the wiring pattern made of the copper foil is formed is passed through a reflow oven for melting and re-solidifying, it is shown in FIG. As described above, when a number of layers of glass fibers are once expanded, they are bonded with an epoxy resin that does not return to its original state, and a wiring pattern is provided on the surface. The printed circuit board A undergoes thermal expansion due to hot air heating in a reflow oven, The printed circuit board A has a higher coefficient of thermal expansion than the wiring pattern between the wiring pattern and the printed circuit board A having different thermal expansion coefficients. Therefore, when the temperature returns to room temperature, the wiring pattern is moved toward the wiring pattern side as shown in FIG. Warp occurs.

Due to this warp, the mounting holes of the printed circuit board A and the mounting holes provided in the fire alarm device do not match, and the printed circuit board A cannot be accurately mounted. Further, if the printed circuit board A is forcibly attached, the wiring pattern may be destroyed, the solder of the electric component B may be peeled off, or the like, which may cause a failure.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a printed circuit board of a fire alarm device having good noise characteristics and eliminating warpage due to thermal expansion. It was done.

[0008]

[Means for Solving the Problems]

 The printed circuit board of the fire alarm device according to the present invention comprises a printed circuit board in which an electric circuit is formed by mounting one side of electric components and the like on the printed circuit board. The slits are formed on a wide area conductive pattern.

[0009]

[Action]

 Slits are formed on a conductive pattern formed on a single-sided printed circuit board over a relatively large area. Then, cream solder is attached to this printed circuit board to mount electric parts and the like, and after hot air heating in a reflow oven that melts and re-solidifies the cream solder, it is naturally cooled to form a printed circuit board without warpage. The warp-free single-sided printed circuit board can be accurately and easily arranged at a predetermined position of the fire alarm device.

[0010]

【Example】

 FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which a door of a fire receiver using a printed circuit board according to the present invention is opened. In the figure, 1 is a box-shaped housing made of a metal plate, 2 is a door made of a metal plate that is attached to the housing 1 via a hinge so as to be openable and closable, and has a window hole slightly above the center. There is. 3 is an operation plate provided on the door 2, 4 is a display plate, 5 is an additional display plate, and 6 is a reinforcing plate of the display plate 4. Reference numeral 7 denotes a substantially rectangular single-sided printed circuit board that is fixed by abutting on the back surface of the display board 4, on which electrical components 7a and the like are mounted. A plurality of slits 7c orthogonal to the direction are provided to prevent warpage of the printed circuit board due to thermal expansion. Reference numeral 8 denotes a double-sided printed circuit board that is fixed by being brought into contact with the back surface of the operation plate 3, and 9 is an insulating paper attached to the back surface of the printed circuit board 8.

Reference numeral 10 is a printed circuit board fixed to the back plate of the housing 1, 11 is a terminal block mounted on the printed circuit board 10, and 12 is a protective plate of the printed circuit board 10. Reference numeral 13 is a transformer attached to the back plate, and 14 is a standby power supply.

In this invention as described above, the operation plate 3, the display plate 4 and the additional display plate 5 are arranged at predetermined positions in the window hole of the open door 2, and the display plate 4 and the operation plate 3 are arranged. The printed circuit boards 7 and 8 are fixed to the back surface of the with screws to connect with the printed circuit board 10 in the housing 1, and the door 2 is closed. Then, the operation panel 3 is operated to drive the fire receiver, and waits for a detection signal sent from, for example, a fire detector. When a fire occurs and a detection signal is sent from the fire detector, an alarm is issued and the indicator light of the area on the display board 4 is turned on.

In the above-mentioned embodiment, the case where a plurality of slits orthogonal to the length direction of the printed circuit board are provided has been described, but a plurality of slits may be provided in the lateral direction, and a comb tooth shape is also possible. Alternatively, it may be formed in a spiral shape.

[0014]

[Effect of the device]

 As described above, in this invention, the slits are formed in the conductive pattern of a relatively large area formed on the single-sided printed circuit board, so that good noise characteristics are secured and the warpage of the printed circuit board due to thermal expansion is eliminated. As a result, it is possible to obtain a printed circuit board for a fire alarm device that can be easily and accurately attached to a housing or the like, and does not cause damage to a wiring pattern or peeling of solder of components.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a door of a fire receiver using the printed circuit board according to the present invention is opened.

FIG. 3 is an exploded perspective view showing an example of a door portion of a conventional fire receiver.

FIG. 4 is a configuration diagram of a single-sided printed circuit board.

FIG. 5 is a side view of the printed circuit board in a thermally expanded state.

[Explanation of symbols]

 1 Case 2 Door 3 Operation Board 4 Display Board 5 Expansion Display Board 7, A Single Sided Printed Circuit Board 7a, B Electric Components 7b Solid Wiring Pattern 7c Slits 8, 10, 34a, 34b Double Sided Printed Circuit Board 9 Insulation Paper

Claims (1)

[Scope of utility model registration request] 1. A printed circuit board having an electric circuit formed by mounting an electric component and the like on one side of the housing, the printed circuit board having an electric circuit formed thereon. A printed circuit board of a fire alarm device characterized by being formed.