Multi-directional switch having a plurality of manual switches

Abstract: A plurality of fixed contacts and a movable contact are provided on a substrate so that opposite contacts form a unit switch. A holding plate having a holding corner is mounted on the substrate, and an operating plunger having a plurality of radially extending arms is slidably mounted in a hole formed in the holding plate, and rotatably held in the holding corner so as to be tilted about the holding corner. A plurality of projections are formed on the underside of the plunger, each of the projections is provided corresponding to the movable contact.

Description: BACKGROUND OF THE INVENTION The present invention relates to a multi-directional switch comprising a plurality of manual switches and used in electronic devices such as a portable telephone, video camera, car radio and others. The multi-directional switch comprises a plurality of fixed contacts circularly arranged in a housing, and an operating plunger tiltably provided in the housing and having a plurality of branches, each having a movable contact which can be contacted with a corresponding fixed contact in the housing by manipulating the operating plunger, thereby producing a specific signal. Fig. 10 is a plan view of a multi-directional switch disclosed in the Japanese Utility Model Application Laid Open, 1-11431, Fig. 11 is a sectional side view of the switch. A multi-directional switch has four push button switches 12 on a substrate 11, disposed on a cross line. An operating plunger 13 has an operating lever 13a, a spherical portion 13c, a conical recess 13d, four restricting portions 13b on the cross line, each restricting portion 13b has a parallelepiped shape. The operating plunger 13 is rotatably held by a spherical portion 15a of a cover of a case 14 and a conical support 16 secured to the substrate 11. The plunger 13 has four receiving arms 13e and four operating arms 13f in the cross line direction. A spring 17 secured to the case 14 engages with each receiving arm 13a, thereby holding the operating lever 13a of the plunger 13 in the vertical position. In accordance with the above described construction, the inclination direction of the plunger 13 is restricted by restricting portions 13b to four directions on the cross line. Four perforations 18 are formed in the spherical portion 15a, each corresponding to the restricting portion 13b. Thus, the plunger 13 can be tilted, inserting the restricting portion 13b in the perforation 18. If the plunger 13 is pushed in other directions than the cross line direction, the plunger 13 can not be tilted since the restricting portion 13b engages with a stopping portion 15b of the cover 15. When the plunger 13 is tilted in one of the four directions the operating arm 13f pushes a push button 12a of one of the switches 12. In the conventional switch 10, since the conical support 16 is provided in the central position of the switch, it is impossible to modify the switch to a versatile switch in which an additional push button switch is provided at the central position. Further, in such a versatile switch, the plunger must be provided so as to be vertically moved to operate the central switch. However, in the conventional switch, the height of the switch becomes large. In addition, since the spherical portion 13c is provided in the central portion, a vertical guide portion for vertically guiding the operating lever 13a is provided on the spherical portion 15a, the height of the switch becomes large, and the construction thereof becomes complicated. Further known multidirectional switches are disclosed in United States patents numbers US-A-5621196 and US-A-5631453 and European patent publication number EP-A-0837419A2. US-A-5621196 describes a multidirectional switch according to the preamble of claim 1, formed by a substrate having a central fixed contact and a plurality of peripheral fixed contacts cooperating with a central movable contact and a plurality of peripheral movable contacts so that opposed pairs of fixed and movable contacts form unit switches, a holding plate mounted on the substrate and forming a first holding corner and an operating plunger with a plurality of radially extending arms slidably mounted in a hole in the holding plate and rotatably held in the holding comer so as to be able to tilt about the holding corner. US-A-5632453 describes a multidirectional switch formed by a substrate having a plurality of spaced apart fixed contacts cooperating with a plurality of spaced apart movable contacts where each of the movable contacts is provided above a fixed contact so that the opposed fixed and movable contact pairs form unit switches in which the unit switches formed by opposed pairs of fixed movable contacts are operated by a plurality of separate operating arms. EP-A-0837419 discloses a multidirectional switch comprising a plurality of fixed contacts, a deformable conductive plate and an operating plunger, in which the deformable plate can be deformed by the operating plunger to contact different ones of the fixed contacts. SUMMARY OF THE INVENTION An object of the present invention is to provide a multidirectional switch having a central switch. Another object is to provide a multidirectional switch which may be reduced in size and height and simple in construction. According to the present invention, there is provided a multidirectional manual switch comprising: a substrate having a central fixed contact and a plurality of peripheral fixed contacts and a central movable contact and a plurality of peripheral movable contacts, each of the movable contacts being provided above each of the fixed contacts so that opposite contacts form a unit switch; a holding plate having a first holding corner formed on an underside thereof and mounted on the substrate; an operating plunger having a plurality of radially extending arms, and slidably mounted in a hole formed in the holding plate, and rotatably held in the first holding comer so as to be tilted about the first holding comer, characterized in that a plurality of peripheral plungers are pivotally held by the holding plate, each of the peripheral plungers being provided above one of the peripheral movable contacts, a plurality of first projections are formed on the underside of the operating plunger, the first projections comprise a central projection corresponding to the central movable contact, and a plurality of peripheral projections, each of the peripheral projections being corresponding to one of the peripheral plungers. The operating plunger is axially slidably held in the holding corner. A plurality of second holding corner are formed on the underside of the holding plate, a peripheral plunger is provided between the peripheral projection and second holding corner so as to be pivoted about the corner, a second projection is formed on the underside of the peripheral plunger, each of the peripheral fixed contacts is offset from the peripheral projection and disposed so that the peripheral movable contact is depressed by the second projection. The stroke between a top of the central projection and a surface of the central fixed contact is smaller than a stroke between a top of the second projection and a surface of the peripheral fixed contact. The length between the peripheral first projection and the second projection is longer than a length between the second projection and the second holding corner. These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a plan view showing a multi-directional switch according to the present invention; Fig. 2 is a sectional view taken along a line II-II of Fig. 1; Fig. 3 is a sectional view taken along a line III-III of Fig. 1; Figs. 4 to 6 are similar drawings to Fig. 1 to 3 for explaining one of operations of the switch; Figs. 7 to 9 are similar drawings to Figs. 1 to 3 for explaining another operation of the switch; Fig. 10 is a plan view of a conventional multi-directional switch; and Fig. 11 is a sectional side view of the switch. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figs. 1 through 3, the multi-directional switch of the present invention comprises a flat body 1 and a flat operating plunger 5. The body 1 is formed by laminating a plastic holding plate 3, a plastic spacer 4 and a substrate 2. As shown in Fig. 1, the body 1 has a square shape. The holding plate 3 has a hole 3a in a shape of a cross. Each branch hole of the hole has a narrow base portion and a wide end portion. The operating plunger 5 has four arms having a similar shape to the hole 3a and is slidably mounted in hole 3a. Each arm of the operating plunger 5 comprises a narrow base portion 5e and a manipulating end portion 5f. The gap between the manipulating end portion 5f and the wall of the hole 3a is small so that the arm may not pivot in the hole. Referring to Figs. 1 and 2, the holding plate 3 has four holding corner 3b between adjacent branch holes 3a. The operating plunger 5 has four projections 5c between adjacent base portions. The projections 5c are rotatably held by the holding corner and prevented from upwardly removing, thereby providing a first fulcrum D. Referring to Fig. 1, five rectangular apertures 4a (two apertures are not depicted) are formed in the spacer 4 at a central portion and at four portions corresponding to manipulating end portions 5f of the operating plunger 5. The rectangular aperture 4a at the end portion 5f is disposed at the right angle to the arm of the plunger 5. In each aperture 4a, a rectangular movable contact 6 is disposed and positioned therein. As shown in Fig. 2, the movable contact 6 has an arcuated shape in section having a central top portion 6a and opposite ends 6b. Each end 6b contacts with a fixed contact 8 provided on the substrate 2. The top portion 6a of a central movable contact 6 is positioned above a central fixed contact 9 on the substrate 2. Referring to Figs. 1 and 2, on the underside of a central portion of the operating plunger 5, a spherical central projection 5a is formed corresponding to the central fixed contact 9, and a spherical peripheral projection 5b is formed on the underside of each manipulating end portion 5f. A peripheral metal plunger 7 having a spherical projection 7a is disposed on the movable contact 6 at the end portion 5f. An inner side end of the peripheral plunger 7 contacts with the spherical projection 5b of the end portion 5f and the outer side end engages with a holding corner 3c of the holding plate 3, and the spherical projection 7a contacts with the top portion 6a of the movable contact 6. Thus, the holding corner 3c provides a second fulcrum E. The stroke S1 (Fig. 2) between the top of the spherical projection 5a and the surface of the fixed contact 9 is set to a value smaller than the stroke S2 (Fig. 3) between the projection 7a and the fixed contact 9 (S1<S2). As shown in Fig. 3, the length L1 from the contact point of the projection 5b with the plunger 7 to the contact point of the projection 7a with the movable contact 6 is set a value larger than the length L2 from the contact point 7a to the second fulcrum E (L1> L2). In operation, referring to Figs. 5 and 6, when a central portion of the operating plunger 5 is depressed by a finger of an operator as shown by an arrow F, the operating plunger is lowered, keeping a horizontal position. Consequently the central movable contact 6 is yielded to be contacted with the central fixed contact 9 on the substrate 2. Thus the fixed contacts 8 are connected to the central fixed contact 9 by the movable contact 6, so that the central switch is closed. At that time, since the stroke S2 is larger than the stroke S1, the projections 7a do not largely deform the peripheral movable contacts 6 as shown in Fig. 6. Therefore, the peripheral switches are not closed. Referring to Figs . 8 and 9, when one of the manipulating end portions 5f of the operating plunger 5 is depressed, the plunger 5 is tilted about the first fulcrum D as shown in Fig. 8. Thus, the spherical peripheral projection 5b deforms the peripheral movable contact 6, so that the movable contact 6 is contacted with the fixed contact 9. Thus, the peripheral switch is closed. At that time, the central projection 5a does not largely move as shown in Fig 8. Therefore, the projection 5a does not largely deform the central movable contact 6. Thus, the central switch is not closed. Since L1 is larger than L2, the projection 7a deforms the movable contact 6 at a small force. In accordance with the present invention, a multi-directional switch having a central switch can be provided. Since the multi-directional switch is composed by a flat body and a flat operating plunger, the thickness of the switch can be reduced and the construction is simple. In addition, since the plunger is mounted in a hole of the body, the thickness is further reduced. While the invention has been described in conjunction with preferred specific embodiment thereof, it will be understood that this description is intended to illustrate and not limit the scope of the invention, which is defined by the following claims.

Claims: a multidirectional manual switch comprising: a substrate (2) having a central fixed contact (9) and a plurality of peripheral fixed contacts and a central movable contact (6) and a plurality of peripheral movable contacts (6), each of the movable contacts being provided above each of the fixed contacts so that opposite contacts form a unit switch; a holding plate (3) having a first holding comer (3b) formed on an underside thereof and mounted on the substrate; an operating plunger (5) having a plurality of radially extending arms, and slidably mounted in a hole (3a) formed in the holding plate, and rotatably held in the first holding corner so as to be tilted about the first holding corner, characterized in that a plurality of peripheral plungers (7) are pivotally held by the holding plate, each of the peripheral plungers being provided above one of the peripheral movable contacts, a plurality of first projections are formed on the underside of the operating plunger, the first projections comprise a central projection (5a) corresponding to the central movable contact, and a plurality of peripheral projections (5b), each of the peripheral projections being provided corresponding to one of the peripheral plungers. The multidirectional manual switch according to claim 1 wherein, the operating plunger is axially slidably held in the holding comer. The multidirectional manual switch according to claim 1 wherein the movable contact has an arcuated shape in section, having a central top portion and opposite ends. The multidirectional manual switch according to claim 1, further comprising a plurality of second holding corner (3b) formed on the underside of the holding plate, a peripheral plunger provided between the peripheral projection and the second holding corner so as to be pivoted about the corner, a second projection (7a) formed on the underside of the peripheral plunger, each of the peripheral fixed contacts being offset from the peripheral projection and disposed so that the peripheral immovable contact is depressed by the second projection. The multidirectional manual switch according to claim 3 wherein the opposite ends of the movable contact are contacted with opposite fixed contacts. The multidirectional manual switch according to claim 4 wherein a stroke (S1) between a top of the central projection and a surface of the central fixed contact is smaller than a stroke (S2) between a top of the second projection and a surface of the peripheral fixed contact. The multidirectional manual switch according to claim 4 wherein the length (L1) between the peripheral first projection and the second projection is larger than a length (L2) between the second projection and the second holding corner.

Inventors: MIYASHITA ISAO, MIYASHITA, ISAO
Applicants: CITIZEN ELECTRONICS, CITIZEN ELECTRONICS CO., LTD.
Application year: 2000
Main classification: H01H25
IPC codes: H01H3, H01H25, H01H21