Directional control-key mechanism

Abstract: A directional control-key mechanism used for a controller of a TV game machine, which mechanism has a long service life. A support member (15) is secured to a key (14) with a circuit board (18) therebetween. A lowermost portion of the support member (15) is in contact with a portion of a bottom case (12) of the controller. The support member (15) has a radially extending portion (15a) under the circuit board (18). a plurality of elastic members (25) are arranged between the circuit board (18) and the radially extending portion (15a). A portion (25a) of each of the elastic members (25) is in a position lifted from the circuit board (18) and a contact material (26) is provided on a top surface of the portion (25a). On a surface of the circuit board (18), there are provided a pair of electrodes at a position directly above the portion (25a).

Description: The present invention relates to a directional control-key device, and more particularly to a directional control-key device used for a controller such as an input device used for playing TV games. In a TV game machine and a portable computer game machine, there is often provided a directional control-key. By using such a key, a player of a TV game can move an image on a display of the TV game machine in a desired direction such as up and down or right and left. The size of the directional control-key is relatively larger than that of a key generally used as an input key of computers. when using the directional control-key, a portion of the key is pressed so that operator can input a desired signal corresponding to the pressed position of the key with respect to the center thereof. A description will be now be given, with reference to Fig.1, of a conventional control-key device of a TV game machine. As shown in Fig.1, a conventional directional control-key comprises a key body 3 having a top surface 3a for being handled by an operator (or player) and a bottom plate 5 fixed on a bottom surface of the key body 3. The bottom plate 5 is provided with a hemispherical member 6 at the center thereof. The key body 3 is positioned above a portion of a circuit board 7 provided in a housing which comprises an upper case 1 and a bottom case 2. The key body 3 is inserted into an opening 1a of the upper case 1 so that the top surface 3a of the key body 3 protrudes from a surface of the upper case 1. A plurality of elastic members 8, made of electrically conductive rubber, are provided between the bottom plate 5 and the circuit board 7 so that the elastic members 8 are radially arranged a predetermined distance apart from the center of the key body 3. Each of the elastic members has a raised portion 8a around the center thereof, and a top surface of the raised portion 8a makes contact with the bottom plate 5. A bottom surface of the raised portion 8a of each of the elastic members 8 is separated from the surface of the circuit board 7 where electrodes are formed. These electrodes are provided so as to generate electric signals when a pair of these electrodes under the raised portion 8a of each of the elastic members 8 are connected by the elastic members 8. The above-mentioned hemispherical member 6 is positioned on the center of the bottom plate 5 between the bottom plate 5 and the circuit board 7 with a small gap 13 formed between a tip of the hemispherical member and the surface of the circuit board 7. It should be noted that the gap 13 between the tip of the hemispherical member and the circuit board is formed because it is difficult to accurately control the height of the elastic members 8 due to the material, namely due to the electrically conductive rubber, of the elastic member 8. Usually, four elastic members and four respective pairs of electrodes are provided on the circuit board so as to generate signals corresponding to up, down, right, and left. When a pressing force is applied to the surface 3a of the key body 3, the key body 3 starts to move downward against an elastic force exerted by the elastic members 8, until the tip of the hemispherical member 6 makes contact with the surface of the circuit board 7. Supposing that the pressing force is applied on the right side, in Fig 1, of the top surface 3a from the center thereof, the key body then starts to pivot about the tip of the hemispherical member 6. Accordingly, after the tip of the hemispherical member 6 is in contact with the circuit board 7, only the elastic member 8 on the right side in Fig.1 is continued to be pressed down. Eventually, the bottom surface of the raised portion 8a of the elastic member 8 on the right side makes contact with a pair of the electrodes positioned under the raised portion 8a. Thereby, the pair of electrodes are electrically connected, resulting in a generation of a signal corresponding to a direction of the position of the top surface 3a to which the pressing force is applied, in this case a signal representing "right". According to the operation of the conventional control-key device, the tip of the hemispherical member 6 hits every time the circuit board 7 when the key body 3 is pressed. The impact of these hits results in wear of the tip of the hemispherical member or the surface of the circuit board 7. If a wear amount becomes large after considerable use of the control-key, then, before the tip of the hemispherical member 6 makes contact with the circuit board 7, the elastic members 8 positioned on opposite sides of the center of the key body 3 are simultaneously pressed against the position where the pair of electrodes located in each of the elastic members are connected by the elastic members 8. This results in malfunctioning of the TV game machine, or difficulty in controlling movement of an image on a display of the TV game machine. US-A-4408103 describes a control-key device in which the key body has a bottom plate formed by a central hemispherical member which rests on a bearing surface, and radially extending arms which depress respective resilient switch contacts against a circuit board when the key body is tilted. The key body has an upper hemispherical dome surface which slides against a cooperating convex casing surface, so that the key body is held in place on the bearing surface by the casing surface. If the bearing surface or the hemispherical member wears, the control-key device becomes looser in operation, and the arms are lowered, reducing the gap between the resilient switch contacts and the circuit board. It is a general object of the present invention to provide an improved and useful directional control-key device used for TV game machines and the like, in which directional control-key device the above-mentioned problems are eliminated. A more specific object of the present invention is to provide a directional control-key device which has a long service life without malfunctioning due to wear of a part thereof. In order to achieve the above mentioned object, a directional control-key device according to the present invention comprises a key and pairs of electrodes, a given pair of electrodes being momentarily connected by means of an elastic member pressed by the key in accordance with a portion of the key being pressed, the directional control-key being characterized in that; the key is connected with a support member having a radially extending portion, the support member having a generally round shaped tip portion being in contact with a base; a circuit board plate is provided between the key and the support member so that the radially extending portion is a predetermined distance apart from a bottom surface of the plate; a plurality of elastic members are provided between the circuit board plate and the support member, each of the elastic members having a portion attached to the circuit board plate and having a lifted portion in a position separated from a surface of the circuit board plate and elastically movable against the surface of the circuit board plate; a contact material is attached on a top surface of each of the lifted portions and a pair of electrodes are provided at a position directly above each of the contact materials on the circuit board plate; an when a pressing force is applied onto a portion of the key, the support member is inclined about a point where the tip portion of the support member is in contact with the base, the contact material provided on an opposite side with regard to the center of the key on the radially extending portion making contact with a corresponding pair of electrodes. According to the present invention, the tip portion of the support member is always in contact with the base and thereby there is no impact force applied to a contacting point. Accordingly, wear of the contact point is less than that of the conventional mechanism. Further, even if the contact point has been worn in the mechanism according to the present invention, there are no undesired influences on the operation of the mechanism because wear of the contact point merely makes a gap between the electrodes and the contact material slightly larger. This gives a completely different effect as compared to the conventional mechanism in which two pairs of electrodes are connected simultaneously when the contact point has been worn. Therefore, no malfunction of the TV game machine occurs due to wear of the contact point. Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. Fig.1 is a cross sectional view of a conventional directional control-key device; Fig.2 is a plan view of a portion of a controller used for playing TV games in which an embodiment of the present invention is incorporated; Fig.3 is a cross sectional view of a directional control-key device according to the present invention; and Fig.4 is a cross sectional view of a variation of the directional control-key device shown in Fig.3. A description will now be given, with reference to Figs.2 and 3, of an embodiment of a directional control-key device according to the present invention. Fig.2 shows a portion of a controller of a TV game machine in which a directional control-key device is incorporated. The controller has a plastic upper case 11, and from a top surface of the upper case 11, a top portion of a directional controlkey-top 14 protrudes. An operator (or a player of the TV game) can control a moving direction of an image on a display of the TV game machine by pressing a portion of the control key-top 14. For example, if the operator presses a right side portion of the control key-top 14, an image (the image may be a character) moves to the right on the display. Fig.3 is a cross sectional view of the controller shown in Fig.2 taken along a line III-III. The directional control-key device according to the present invention comprises a key body 20 and a plurality of elastic members 25. The key body 20 comprises the key-top 14 and support member 15 secured to a stem 14a of the key-top 14 by a screw 17. The support member has a radially extending portion 15a, and in an opening of the support member 15 in which opening the screw 17 is inserted is provided with a tip portion 16 having a convex shape directing downward. The tip portion 16 is press fitted into the opening of the support member 15. The stem 14a of the key-top 14 extends through a hole 18a provided on a circuit board 18 in the upper case 11. The tip portion 16 is placed on a protrusion 12a of a bottom case 12 of the controller. A top portion of the key-top 14 protrudes from an opening 11a of the upper case 11 so that the operator can press a desired portion of a top surface 14b of the key-top 14. Under the key-top 14 and between the key-top 14 and the support member 15, there is provided a circuit board plate 18 on which a circuit necessary for the controller is formed. The circuit board plate 18 is fixed to the bottom case 12. The stem 14a extends through a hole 18a formed on the circuit board plate 18. Between the radially extending portion 15a of the support member 15, a plurality of elastic members 25 are provided. Each of the elastic members 25 is attached to a bottom surface of the circuit board plate 18 so that they are arranged on a circumference. Each of the elastic members 25 has a portion 25a having a relatively large thickness and being in a portion separated from the surface of the circuit board plate 18. Accordingly, there is formed a gap between the top surface of the portion 25a and the bottom surface of the circuit board plate 18. The portion 25a is supported by a relatively thin portion 25b and thereby the top portion 25a is allowed to elastically move up and down. A bottom surface of the portion 25a is in contact with a top surface of the radially extending portion 15a and the support member 15 is thereby always pressed to the protrusion 12a of the bottom case 12. On a top surface of the portion 25a of each of the elastic members 25, a contact material 26 is attached and a pair of electrodes 27 are provided on the bottom surface of the circuit board plate 18 at a position directly above the contact material 26. The electrodes 27 are part of an electrical circuit formed on the circuit board plate and the electrical circuit is so formed to generate a signal used for moving an image on the display when the pair of electrodes is electrically connected. A description will now be given, with reference to Fig.3, of an operation of the above-mentioned directional control-key mechanism. When a pressing force is applied to a portion of the right side of the top surface 14b, it means an operator desires to move an image on the display to the right, the key body 20 is then inclined to the right side about a point where the tip portion 16 is in contact with the protrusion 12a of the bottom case 12. Accordingly, the radially extending portion 15a of the support member 15, on the left side in the figure, is lifted up. As the key body 20 inclines, the portion 25a of the elastic member 25 positioned on the lifted radially extending portion 15a comes closer to the circuit board. Finally, the contact material 26 on the portion 25a makes contact with a pair of electrodes 27 on the left side of the figure, resulting in connection of the pair of electrodes 27. When the pressing force is released, the key body 20 returns to its original position due to an elastic force exerted by the elastic members 25. Similarly to the above-mentioned operation, if a force is applied on the left side of the key-top 14, the electrodes on the right side are connected. In the above-mentioned mechanism, the tip portion 16 is always in contact with the surface of the protrusion 12a and thereby there is no impact force applied to a contacting point. Accordingly, wear of the contact point is less than that of the conventional mechanism. Further, even if the contact point has worn in the mechanism according to the present invention, there is no influences to the operation of the mechanism because wear of the contact point merely makes a gap between the electrodes 27 and the contact material 26 slightly larger. This gives a completely different effect as compared to the conventional mechanism in which two pairs of electrodes are connected simultaneously when the contact point has worn. Therefore, in the mechanism according to the present invention, no malfunction of the TV game machine occurs due to wear of the contact point. It should be noted that, similarly to the conventional mechanism, the elastic member 25 may be made of electrically conductive rubber instead of providing the contact material on the top surface of the portion 25a of each of the elastic material 25. Fig.4 is a variation of the embodiment according to the present invention shown in Fig.3. In this Fig.4, parts that are the same as those shown in Fig.3 are given the same reference numerals as previously, and descriptions thereof will be omitted. In the variation shown in Fig.4, a key body 30 comprises a key-top 14 and support member 35 which is press fitted to a hole 35b formed on a stem 14a of the key-top 14. A tip portion 35c is formed as a part of the support member 35. A radially extending portion 35a corresponds to the radially extending portion 15a shown in Fig.3. According to this variation the key body 30 comprises fewer parts than the key body 20 shown in Fig.3. Additionally, assembly of the key body 30 is simply performed by press fitting without using tools such as a screw driver. Thus this variation can reduce manufacturing costs while having the same advantages as those in the embodiment shown in Fig.3

Claims: A directional control-key device comprising a key-top (14) and pairs of electrodes (27), a given pair of electrodes being momentarily connected by means of an elastic member pressed by the key-top in accordance with a portion of the key-top being pressed, the directional control-key device being characterized in that: said key-top (14) is connected with a support member (15) having a radially extending portion (15a), said support member (15) having a generally round shaped tip portion being in contact with a base (12a); a circuit board plate (18) is provided between said key-top (14) and said support member (15) so that said radially extending portion is a predetermined distance apart from a bottom surface of said circuit board plate (18); a plurality of elastic members (25) are provided between said plate circuit board (18) and said support member (15), each of said elastic members (25) having a portion attached to said circuit board plate (18) and having a lifted portion (25a) in a position separated from a surface of said plate (18) and elastically movable against the surface of said circuit board plate (18); a contact material (26) is attached on a top surface of said lifted portion (25a) and a pair of electrodes (27) are provided at a position directly above said contact material (26) on said circuit board plate (18); and when a pressing force is applied onto a portion of said key-top (14), said support member (15) is inclined about a point where said tip portion of said support member (15) is in contact with said base (12a), said contact material (26) provided on an opposite side of the portion where the pressing force is applied with regard to the center of said key-top (14) on said radially extending portion (15a) making contact with said corresponding pair of electrodes (27). The directional control-key device as claimed in claim 1, characterized in that: said key-top (14) has a stem (14a) extending through an opening (18a) of said circuit board plate (18), and said support member (15) is secured to said stem (14a). The directional control-key device as claimed in claim 2, characterized in that: said stem (14a) has a hole (35b) and said support member (35) is press fitted into said hole (35b). The directional control-key device as claimed in claim 1, characterized in that: said circuit board plate (18) is comprised of a circuit board on which an electric circuit is formed, and said circuit board is secured to a housing (12), said base (12a) being formed as a part of said housing (12). The directional control-key device as claimed in claim 1, characterized in that : said movable portion and said portion of elastic material are made of electrically conductive rubber instead of providing said electrical contact (26) on said movable portion.

Inventors: MATSUMIYA HIROSHI, MATSUMIYA, HIROSHI
Applicants: SEGA ENTERPRISES KK, SEGA ENTERPRISES, LTD.
Application year: 1993
Main classification: H01H25
IPC codes: H01H25, H01H13