JPS61292825A - Keyboard - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a keyboard used as an input device for an electronic typewriter 9, a personal computer, OA equipment, etc. The present invention relates to a keyboard in which stretch or wrinkles are not caused in a circuit pattern board due to thermal expansion or contraction of a frame due to temperature fluctuations.

<Prior Art> Conventionally, keyboards used as input devices for electronic typewriters, office automation equipment, etc. generally include a frame that supports a large number of keys in a vertically movable manner, and a coil spring that biases each key upward. It consists of an elastic member such as a rubber spring or a rubber spring, a membrane switch with a circuit pattern including electrodes formed on a film with a spacer interposed, and a support plate that supports the membrane switch from below. The support plate is fixed to the upper cover.

<Problems to be Solved by the Invention> Furthermore, since the membrane switch is not directly positioned on the frame that holds the key, a misalignment occurs in the position of the key press operation part and the electrode of the membrane switch. was there. For this purpose, the membrane switch was completely fixed to the frame with screws, etc., but if the frame is made of synthetic resin, etc., which has greater thermal expansion and contraction than the membrane switch, the frame Thermal expansion and contraction of the membrane switch causes tension and wrinkles in the membrane switch, causing chattering and key-in delays in the switching operation of the electrodes.

<Objective of the Invention> The present invention has been made in consideration of the above points, and is capable of accurately positioning a circuit pattern board with respect to a frame, without causing misalignment between the suppression actuation part of the key and the electrode of the circuit pattern board, It is an object of the present invention to provide a keyboard that does not cause tension or wrinkles on a circuit pattern board due to thermal expansion or contraction of a frame, and can prevent chattering and key-en delay.

Means to solve problems〉 In order to achieve the above object, the keyboard of the present invention is provided.

A large number of keys whose key stems are guided and supported in the vertical direction by a frame, and a circuit pattern board that includes the same number of sets of electrodes as the keys, which are always electrically insulated, and the electrode sets are electrically connected when the keys are pressed. , a keyboard having an elastic member interposed between a key and a circuit pattern board to normally hold the key in an inoperative position, the frame facing the circuit pattern board and extending along the longitudinal direction of the circuit pattern board. The pattern board has three positioning protrusions that protrude downward on a line, and the pattern board has oval holes that fit with the respective positioning protrusions at positions facing the positioning protrusions, and among the three oval holes, the central oval The longitudinal direction of the hole is perpendicular to the longitudinal direction of the circuit pattern board, and the oval holes on both sides are configured so that their longitudinal directions are parallel to the longitudinal direction of the circuit pattern board.

<Example> An embodiment of the present invention will be briefly described below with reference to the drawings.

Fig. 1 shows an exploded perspective view of the keyboard in an electronic typewriter, Fig. 2 shows a lateral sectional view of the keyboard, Fig. 3 shows an enlarged sectional view of the key switch section, and Fig. 4 shows a frame 1. A back view is shown.

The flat frame 1 constituting the upper cover of the keyboard is integrally molded from ABS resin, etc., and has a number of holes 9 in a predetermined arrangement into which key stems are inserted, and the surface has holes 9 around which the key stems can be moved up and down. Guide tube 2 that guides
is installed protrudingly. On the back surface of the frame 1, as shown in FIG. 4, an annular pressing part 3 is provided protruding around the hole 9, and
Three positioning protrusions 4, 5, 6 are protruded along the longitudinal direction of the circuit pattern board (to be described later), that is, on a straight line in the lateral direction, for positioning the circuit pattern board and the frame 1. Note that the three wooden protrusions 7 protruding from the bottom of the frame 1 in FIG. A large number of bosses 8 are provided protrudingly.

An elastic member 10 for biasing the key upward is disposed on the lower side of the frame 1. This elastic member 10 is formed into a sheet shape of silicone rubber, for example, and is supported by the frame l so as to be able to move up and down. An inverted cup-shaped bulge 11 is protruded at a position corresponding to each key, and a switch operating part 11a for pushing the membrane switch 12 is formed inside the center of the inverted cup-shaped bulge 11. The elastic member 10 has positioning protrusions 4, 5, 6 and 7, which protrude from the back surface of the frame 1. A hole into which the screw hole post 8 is inserted is bored at a predetermined location.

The membrane switch 12 is a known thin film switch in which a circuit pattern including electrodes is formed on the opposing surfaces of a pair of insulating films such as polyester films, and a spacer is interposed. A metal support plate 13 and a circuit pattern board 20
is configured.

When the circuit pattern board, that is, the membrane switch 12 and the support plate 13 are accurately positioned and stacked on the back side of the frame 1, the positioning protrusions 4.5 of the frame 1.
Membrane switch 12 and support plate 1 located opposite to 6
There are 14 oval holes on each of the 3.・15.16 will be drilled. These oval holes 14, 15, 16 are provided on a straight line along the longitudinal direction of the circuit pattern board 20, and are formed to fit into the positioning protrusions 4, 5, 6, respectively.

The longitudinal direction of the center oval hole 15 is the circuit pattern board 2.
The oval holes 14 and 16 on both sides are formed such that their longitudinal directions are parallel to the longitudinal direction of the circuit pattern board 20. In addition, on the membrane switch 12, holes that loosely fit into the threaded post holes 8 of the frame l are bored at opposing locations, and on the support plate 13, holes with a smaller diameter than the threaded post posts 8 are formed on opposite sides of the respective bosses. provided at certain locations.

A key stem 18 of a key 17 is fitted into each guide tube 2 of the frame 1 so as to be vertically movable. It is urged upward by the member 10, and the upside-down piece provided at the lower end of the member 10 engages with the frame 1, thereby regulating the upper limit of its protrusion.

Each member of the keyboard configured as described above is assembled in the assembly process as follows. First, the elastic member 10 is placed on the upside-down frame 1, and the elastic member 10 is inserted with its inverted cup-shaped bulging portion 11 into the annular pressing portion 3 on the back side of the frame, and at the same time inserts the elastic member 10 into the hole provided at a predetermined location. are inserted into the positioning protrusion 4.5.6, protrusion 7, and screw hole post 8 on the frame side, thereby performing accurate positioning, and the membrane switch 12 is placed on the elastic member lO. , the support plate 13 is placed on the membrane switch 12, and at this time, the oval holes 14, 15, 16 provided in the membrane switch 12 and the support plate 13 are
positioning protrusions 4. each protrude onto the elastic member 1θ.
5.6 is fitted. The membrane switch 12 and the support plate 13 are accurately positioned in the lateral direction, that is, in the longitudinal direction of the circuit pattern board 20, by fitting the oval hole 15 in the center with the positioning protrusion 5, and the oval holes 14, 16 and the positioning protrusion on both sides. By fitting 4.6, the positioning in the vertical direction, that is, in the direction orthogonal to the longitudinal direction of the circuit pattern board 20 is accurately positioned, and the assembly can be carried out quickly without causing any looseness or wrinkles or tension on the membrane switch 12. , assembly is performed with high precision. Then, screws are screwed into each screw hole post 8 from the back surface of the support plate 13, and the circuit pattern board 20 is screwed to the frame 1 with the elastic member 10 interposed therebetween.

In the keyboard having such a structure, when the key 17 is pressed down, the inverted cup-shaped bulge 11 of the elastic member 10 is pushed down by the key stem 18, and the switch actuating part 11a formed inside the bulge 11 is moved onto the circuit pattern board 20. This causes the upper film of the membrane switch 12 to bend and bring the upper and lower electrodes into contact with each other, but the frame 1 deforms due to thermal expansion and contraction, causing wrinkles and tension in the membrane switch 12. In this case, chattering and key-in delays are likely to occur in the switching operation.

However, in the keyboard with the above configuration, a resin with larger thermal expansion and thermal contraction than that of the circuit pattern board 20 is used for the frame 1, and even if the frame 1 expands and contracts relatively largely due to heat, the The oval holes 14 allow displacement of the positioning protrusions 4.6 on both sides, which expand and contract the most with the center as a reference, and for this reason, the membrane switch 12 is wrinkled by thermal expansion and contraction of the frame l. Chattering in switching operations and key-in delays can be prevented without causing tension or tension.

In the above embodiment, the elastic member 10 is a so-called rubber spring, but an elastic member such as a coil spring may also be used.Also, instead of a membrane switch, the circuit pattern board 20 may include a rubber spring on the same surface of a hard board. It is also possible to use a patterned substrate on which a pair of electrodes are provided, and to provide a conductive part that makes the electrodes conductive in the switch operating part.

<Effects of the Invention> As explained above, according to the keyboard of the present invention, three positioning protrusions are provided protruding in a straight line along the longitudinal direction of the circuit pattern board on the back surface of the frame, and one positioning protrusion is provided on one circuit pattern board. An oval hole is provided at a position facing each positioning protrusion, the longitudinal direction of the central oval hole is perpendicular to the longitudinal direction of the circuit pattern board, and the longitudinal direction of the oval holes on both sides is parallel to the longitudinal direction of the circuit pattern board. It was configured to do so. Therefore, during manufacturing, by fitting these positioning protrusions with the oval holes, the circuit pattern board can be accurately positioned and assembled to the frame, and a frame with larger thermal expansion and contraction than the circuit pattern board can be used. Even if the frame expands or contracts due to heat, the oval holes on both sides prevent the displacement of the positioning protrusions on both sides, which are likely to become misaligned, thereby reducing wrinkles and tension on the circuit pattern board caused by thermal deformation of the frame. Chattering and key-in delays caused by this can be prevented.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is an exploded perspective view of the keyboard, Fig. 2 is a cross-sectional view of the keyboard in the lateral direction, Fig. 3 is an enlarged sectional view of the key switch section, and Fig. 4 is the back side of the frame. It is a diagram. l... Frame, 4.5.6... Positioning protrusion, 10... Elastic member, 14.15.16... Oval hole, 17... Key, 20... Circuit pattern board. Patent applicant II 1 Figure

Claims (1)

[Scope of Claims] A key stem includes a large number of keys guided and supported in the vertical direction by a frame, and the same number of sets of electrodes as the keys, which are always electrically insulated, and the electrode sets are electrically connected when the keys are pressed. A keyboard comprising a circuit pattern board connected to the circuit pattern board, and an elastic member interposed between the key and the circuit pattern board to normally hold the key in an inoperative position, the frame facing the circuit pattern board. The circuit pattern board has three positioning protrusions projecting downward in a straight line along the longitudinal direction of the circuit pattern board, and the pattern board has oval holes in positions facing the positioning protrusions that fit with the respective positioning protrusions. Of these three oval holes, the longitudinal direction of the central oval hole is perpendicular to the longitudinal direction of the circuit pattern board, and the longitudinal direction of the oval holes on both sides is parallel to the longitudinal direction of the circuit pattern board. A keyboard featuring