JPS6136023Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a push button switch.

Push button switches installed in small electronic devices such as small electronic calculators are equipped with a contact sheet made of an elastic insulating material with a plurality of movable contacts formed on the bottom side above the circuit board, and when the push button is pressed, the contact sheet is moved from the top side. A device is used in which the movable contacts are brought into contact with fixed contacts formed on the circuit board by pressing from the side.

The contact sheet used in this push button switch has a recess formed on the lower surface of the sheet in order to obtain the stroke of the movable contact relative to the fixed contact, and a movable contact formed on the bottom surface of this recess.

However, in recent years, as electronic devices have become more multi-functional, the wiring configuration of circuit boards has become more complex. Therefore, in order to simplify the wiring configuration on the circuit board, leads that connect to the movable contacts are placed on the bottom surface of the contact sheet. is formed in one direction in which the contacts are arranged (for example, in the row direction), and leads that connect to the fixed contacts are formed on the upper surface of the circuit board in the other direction in which the contacts are arranged (for example, in the column direction). However, in this case, an insulating plate must be interposed between the contact sheet and the circuit board in order to insulate the leads on the lower surface of the contact sheet from the circuit board. For this reason,
The disadvantage is that the push button switch is thicker and has a larger number of parts, making assembly difficult and uneconomical.

By the way, the open part of the recessed part of the contact sheet is closed by the circuit board, and air accumulates inside. When pressing the contact sheet with a push button, the air in the recessed part acts as resistance, which hinders the pressing operation. For this reason, air escape grooves are formed on the lower surface of the contact sheet to communicate with each of the recesses in order to release the air in the recesses.

The present invention was developed in view of the above circumstances, and includes an air escape groove in the contact sheet, a lead connected to the movable contact and the terminal electrode in the air escape groove, and a board placed on the bottom surface of the contact sheet. By providing fixed contacts and terminal electrodes corresponding to the movable contacts and terminal electrodes, there is provided a push button switch which eliminates the need for an insulating spacer and which can greatly simplify the switch structure.

An embodiment of the present invention will be described below with reference to drawings.

This embodiment is a case in which the push button switch of the present invention is installed in a small electronic calculator, and is shown in Figs. 1 and 2.
The figure shows a push button switch, and FIG. 3 shows a contact sheet. In the figure, 1 is an upper case, 2 is a lower case combined with the upper case 1, and 3 is a circuit board provided in these cases 1 and 2. A plurality of button holes 4 are formed in the upper case 1 and arranged in row and column directions, and push buttons 5 are provided in these button holes 4 so as to be movable up and down. On the upper surface of the circuit board 3, a plurality of fixed contacts 6 are formed by a printing method in rows and columns, and for example, leads 7 connecting the movable contacts 6 arranged in the column direction (width direction of the circuit board 3) are connected to each movable contact. Each row of contacts is formed by a printing method. Note that a plurality of terminal electrodes 8 are formed at one end of the upper surface of the circuit board 3.

The contact sheet used in this invention is upper case 1.
The sheet body 9 is provided in a layered structure between the circuit board 3 and the circuit board 3, and has a sheet body 9 made of an elastic insulating material such as insulating rubber such as silicone rubber. A plurality of circular convex portions 10 are formed on the upper surface of the sheet body 9 and are arranged side by side in the row and column directions, and a presser protrusion 9a is formed to protrude from one end. A plurality of circular recesses 11 are formed on the lower surface of the seat body 9 and are arranged in the row and column directions, and these recesses 11 face the protrusions 10 on the upper surface of the seat. Further, air escape grooves 12 are formed on the lower surface of the seat body 9 for each row of movable contacts, for example, connecting the recesses 11 arranged in the row direction (the longitudinal direction of the seat body 9). 12
One end extends from the recess 11 located on one end side of the seat body 8 and is gathered at the base of the protruding piece 9a,
The other end extends from the recess 11 located on the other end side of the seat body 8 to the other end edge of the seat body 3 to form an open part 12a. Note that the bottom surface of the recess 11 and the air escape groove 12 have the same depth, and the bottom surface of the recess 11 and the bottom surface of the air escape groove 12 are on the same plane. Therefore, the recesses 11 in the row direction communicate with each other through the air escape grooves 12. Furthermore, each recess 11
A circular movable contact 13 is formed at the center of the bottom surface of each by printing. Leads 14 are printed on the bottoms of the air escape grooves 12 in each row of the recesses 11, and these leads 14 connect the movable contacts 13 formed on the bottoms of the recesses 11 in each row to each other. ing. Therefore, each lead 14 is formed along the row direction, and each movable contact 13 arranged in the row direction is formed with a lead 14 for each row.
Connected with Note that each lead 14 extends from the movable contact 11 on one end side of the seat body 9 to one end of each air escape groove 12, and
The protruding pieces 9a of the sheet body 9 are formed so as to extend therefrom and connect to a plurality of terminal electrodes 15 formed on the lower surface of the protruding piece 9a of the sheet body 9, respectively. Movable contact 13 and lead 14
is formed on the bottom surface of the recess 11 and the air escape groove 12 and is located inside the bottom surface of the seat body 9, and has an insulating distance from the parts provided outside the bottom surface of the seat body 9. The depth of the recess 11 and the air escape groove 12 is set so that the movable contact 13 and the lead 14 have an insulating interval.

The sheet body 9 is provided overlappingly on the upper surface of the circuit board 3, and each recess 11 surrounds each fixed contact 6 of the circuit board 3, and each movable contact 13 faces above each fixed contact 6. The terminal electrodes 15 of the sheet body 9 are in direct contact with the terminal electrodes 8 of the circuit board 3. In this case, the lower open portions of the recess 11 and the air escape groove 12 of the seat body 9 are closed by the circuit board 3. An upper case 1 combined with a lower case 2 is provided on the upper side of the seat body 9, and the upper case 1 fixes the seat body 9 onto the circuit board 3 by pressing the protrusion 9a. The convex portion 10 of the seat body 9 supports and pushes up the push button 5 of the upper case 1.

Then, the convex portion 1 of the seat body 9 is pressed via the push button 5.
When 0 is pressed downward from above, the portion of the sheet body 9 where the concave portion 10 is formed elastically bends downward, so that the movable contact 13 also moves downward and comes into contact with the fixed contact 6 on the circuit board 3. In this case, the air accumulated in the recess 11 of the seat body 9 is pushed out by the deflection of the seat body 9, and
Since it passes through the interior and is discharged to the outside from the open portion 12a, the pressing operation against the sheet body 9 can be performed satisfactorily. When the pressing force from the push button 5 is released, the seat body 9 returns to its original state due to its elasticity, and the movable contact 1
3 is separated from the fixed contact 6.

Therefore, in the contact sheet used for this push button switch, the lead 14 connected to the movable contact 13 is
is formed at the bottom of the air escape groove 12 on the lower surface of the seat body 9 and is located inside the lower surface of the seat body 9 at a predetermined distance, so that the upper surface of the circuit board 3 that contacts the lower surface of the seat body 9 and this It does not come into direct contact with wiring such as leads formed on the top surface, but is spaced apart by a predetermined insulating interval. Since the sheet body 9 has an insulating property, even if it comes into direct contact with the circuit board 3 and its wiring, the wiring of the circuit board 3 and the leads 14 will not be electrically connected via the sheet body 9. Therefore, insulation can be maintained between the leads 14 of the sheet body 9 and the wiring of the circuit board 3 without providing an insulating spacer. Therefore, the sheet body 9 with the leads 14 formed on the lower surface side can be directly superimposed on the circuit board 3 without intervening an insulating spacer. Moreover, since the leads 14 are formed by effectively utilizing the space of the air escape grooves 12 conventionally formed in the sheet body 9, special structural or manufacturing measures such as insulating coatings are required to insulate the leads 14. There is no need to take any measures. Then, a wiring structure in which the leads 14 for connecting the movable contacts 13 to the sheet body 9 of the contact sheet and the leads 7 for connecting the fixed contacts 6 to the circuit board 3 are divided into the row and column directions is connected to the sheet body 9 and the circuit. It can be employed without using an insulating spacer between it and the substrate 3.

Note that the air escape grooves in the seat body are not limited to the row direction, but may be formed in the column direction or other directions. The leads in the sheet body can be formed in the air escape groove along that direction so as to suitably connect the movable contacts, and are not limited to being formed along the row direction as in the embodiment. Although it is preferable to form the lead on the bottom surface of the air escape groove in terms of insulation from the circuit board, it is also possible to form the lead on the side wall of the air escape groove if this insulation can be achieved. Further, the form of the recessed portion of the seat body is not limited to the embodiment. The convex portion of the seat body may be formed to be integrated with the push button, for example, and does not necessarily need to be formed. This contact sheet can be widely applied to push button switches used in small electronic devices.

As explained above, the push button switch of this invention is
The air escape groove of the contact sheet is effectively used to form a lead, and the terminal electrode connected to the lead directly connects the contact sheet and the circuit board without using an insulating spacer or the like, allowing both to be connected at the same time. Since the terminal electrodes of the switch can be connected, the switch can be made thinner and the number of parts can be reduced, making assembly easier and more economical. Moreover, since there is no need to take any special measures to insulate the leads, it is very advantageous and economical in terms of structure and manufacturing.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is an exploded perspective view showing the case where the push button switch of the present invention is applied to a small electronic calculator; Fig. 2 is a sectional view showing the push button switch; FIG. 3 is a perspective view of the contact sheet viewed from the bottom side. 1... Upper case, 2... Lower case, 3...
Circuit board, 5...Push button, 6...Fixed contact, 7...
Lead, 9...Sheet body, 10...Protrusion, 11
... recess, 12 ... air escape groove, 13 ... movable contact, 14 ... lead.

Claims (1)

[Scope of utility model registration request] A sheet main body made of an elastic insulating material in which a recess for forming a movable contact is formed on one side and an air escape groove is formed by connecting these recesses, and the recess is pressed from the other side; a contact sheet provided with a movable contact, a lead formed in the air escape groove and connected to the movable contact, and a portion of which is a terminal electrode; A push button comprising a fixed contact corresponding to a movable contact of a contact sheet, and a substrate connected to the fixed contact and provided with a lead whose part is a terminal electrode corresponding to the terminal electrode of the contact sheet. Switch.