Switch structure of electronic device

Abstract: This invention copes with miniaturization of an electronic device and provides a switch structure of the electronic device at inexpensive price. The switch structure of the electronic device comprises a case (an upper case 1 and a lower case 4) having supporting convex portions 4f, 4f, switches 3a, 3a mounted within the case, and a push button 2 containing arm portions 2c, 2c, 2c, 2c elastically deformable, push button portions 2b, 2b, and switch pushing convex portions 2e, 2e provided on an end of a surface of each push button portion. One end of each arm portion which is far from each push button portion is fixed to the case. Each supporting convex portion is provided so as to contact a position nearer each arm portion relative to a center of each push button portion, on the surface of each push button portion during the operation of each push button portion. Each switch pushing convex portion actuates each switch when the operation of each push button portion has terminated.

Description: BACKGROUND OF THE INVENTION: This invention relates to a structure of a switch of an electronic device like, for example, individual call signal receiver and more particularly to a structure of a switch of an electronic device of high-density parts mounting. Conventional switches such as known from GB-2300074 used in electronic devices often use a structure like seen in tact switches, in which a switch designed to be turned on by being pushed down is to be pushed by a push button provided upward. In document DE 9 013 577 U, the push-button carrying member is hinged on one face, and actuates a switch on the other face. Fig. 1 shows a schematic view showing an example of a conventional electronic device switch structure. This kind of the conventional switch has been disclosed in for example Japanese Unexamined Patent Publication (JP-A) No. 29449 of 1955. A push button 11 comprises an arm portion 11a, a push button portion 11b, and a switch pushing convex portion lic. A proximal portion of the arm portion 11a elastically deformable is fixed to a case 12. The push button portion 11b is disposed on a top face of an end portion of the arm portion 11a and the switch pushing convex portion 11c is provided on a bottom thereof. A tact switch 13 is provided downward of the switch pushing convex portion 11c. When the push button portion 11b is pushed, the arm portion 11a is elastically deformed, so that the switch pushing convex portion 11c comes into contact with the tact switch 13. If the arm portion 11a is further elastically deformed, the tact switch 13 is pushed by the switch pushing convex portion 11c so that this switch is turned on. When a force pushing the push button portion 11b is released, the arm portion 11a elastically deformed is returned to its original position. As a result, the switch pushing convex portion 11c leaves the tact switch 13 so that the tact switch 13 is turned off. If this kind of the switch structure is applied to an individual call signal receiver, for example, a substrate and the like are arranged below an indication panel, and therefore in many cases, a battery is contained downward of the push button portion 11b. In the individual call signal receiver in which a battery is contained downward of the push button portion 11b as described above, if it is intended to reduce the thickness of the case 12, a strong force is required for an operation of the push button portion 11b. This reason is that in the individual call signal receiver having such a structure, if the thickness of the case 12 is reduced, the conventional switch structure shown in Fig. 1 is applied, so that the switch portion is arranged beside of the battery. At this time, there is no sufficient gap in the horizontal and vertical directions, so that the length of the arm portion 11a cannot be obtained sufficiently. Thus, when the push button portion 11b is pushed down, the arm portion 11a indicates a behavior like a rigid structure, so that the motion of the push button portion 11b requires a strong force. On the contrary, if it is intended to weaken a force required for the operation of the push button portion 11b, in the individual call signal receiver in which a battery is contained downward of the push button portion 11b, there is no way but locating a switch between the push button portion 11b and the battery. Thus, the thickness of the case 12 must be increased. As a switch capable of satisfying these two contradictory requirements, for example a key board switch has been known. However, this kind of the switch costs too much. SUMMARY OF THE INVENTION: Accordingly, an object of the present invention is to provide a switch structure of an electronic device coping with miniaturization of electronic devices. Another object of the present invention is to provide a switch structure of an electronic device which can be produced at small cost. According to the present invention, there is provided a switch structure of an electronic device, as claimed in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS: Fig. 1 is a perspective view of an example of a switch structure of a conventional electronic device; Fig. 2 is a perspective view of an individual call signal receiver using a switch structure of an electronic device according to an embodiment of the present invention. By removing part of an upper case, a push button, and a substrate, the interior of the individual call signal receiver can be seen; Fig. 3 is a disassembly perspective view of the individual call signal receiver using the switch structure of the electronic device according to the embodiment of the present invention. The push button and the upper case are expressed upside down; Fig. 4A is a front view of the individual call signal receiver using the switch structure of the electronic device according to the embodiment of the present invention; Fig. 4B is a rear view of the individual call signal receiver using the switch structure of the electronic device according to the embodiment of the present invention; Fig. 5A is a sectional view showing a state before the operation of the push button is started in major parts of the individual call signal receiver using the switch structure of the electronic device according to the embodiment of the present invention; Fig. 5B is a sectional view showing a state showing halfway of the operation of the push button in major parts of the individual call signal receiver using the switch structure of the electronic device according to the embodiment of the present invention; and Fig. 5C is a sectional view showing a state showing that the operation of the push button has terminated in major parts of the individual call signal receiver using the switch structure of the electronic device according to the embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS: A preferred embodiment of the present invention will be described with reference to Figs. 2-5. Of course, the present invention is not restricted to this embodiment, but defined by the appended claims. An individual call signal receiver case comprises an upper case 1 and a lower case 4 as shown in Fig. 2. As shown in Fig. 3 (a push button 2 and the upper case 1 are expressed upside down), the upper case 1 has holes 1a, 1a through which two push button portions 2b, 2b pass and ribs 1b, 1b, 1c, 1c, 1d, 1d for fixing the push button 2. The push button 2 comprises a fixing portion 2a for fixing the push button 2, the push button portions 2b, 2b for a user to use and arm portions 2c, 2c, 2c, 2c. The fixing portion 2a is of substantially square rod and four arm portions 2c, 2c, 2c, 2c are provided on one of external faces thereof. The arm portions form two pairs each comprising two arm portions. The arm portions are connected by substantially semi-circular flange portions 2d, 2d. As shown in Fig. 2, on top faces of the flange portions 2d, 2d are provided the push button portions 2b, 2b in elliptic shape of a smaller size. As shown in Fig. 3, on front ends of bottoms of the flange portions 2d, 2d are provided switch pushing convex portions 2e, 2e. Between the arm portions 2c and 2c are provided cutout portions 2f, 2f. In the cutout portions 2f, 2f are projected substantially half the push button portions 2b, 2b, and rear faces of the projected portions are push button rear faces 2g, 2g. Further, grooves 2h, 2h are provided in the middle portion of the arm portions 2c, 2c of the fixing portion 2a. Further, the fixing portion 2a has holes 2i, 2i which the ribs 1d, 1d of the upper case 1 enter. On a substrate 3 are disposed switches 3a, 3a, such that they are arranged at the same distance as that between the switch pushing convex portions 2e, 2e. The lower case 4 has ribs 4a, 4a for supporting the switches 3a, 3a of the substrate 3 from below. A part of the lower case 4 is partitioned by a battery mounting wall 4b, and as shown in Figs. 5A-5C, a battery 5 is mounted in the battery mounting chamber 4c. An end portion of the battery mounting wall 4b acts as a supporting point portion 4d and dust proof convex portions 4e, 4e which can be contained in the cutout portions 2f, 2f are provided near a portion of the battery mounting wall 4b which is in contact with the fixing portion 2a of the push button 2. On each top face of the dust proof convex portions 4e, 4e is provided a semi-spherical supporting convex portion 4f. Further, each portion of the dust proof convex portions 4e, 4e is formed as a nails 4g projecting out from an end of the battery mounting wall 4b. Referring to Figs. 2 and 3, relations of the respective components will be described further in detail. The holes 1a, 1a are slightly larger than the push button portions 2b, 2b and smaller than the flange portions 2d, 2d. As a result, foreign matter cannot enter the interior of the case easily. The ribs 4a 4a support the switches 3a, 3a from below so that even when the switch pushing convex portions 2e, 2e push the switches 3a, 3a, the substrate 3 is not warped. The nails 4g, 4g of the lower case 4 engage the grooves 2h, 2h of the push button 2. Thus, the push button 2 can be fixed further firmly to the lower case 4. Thus, when the push button portions 2b, 2b are operated, the battery mounting wall 4b never rides over the fixing portion 2a of the push button 2. On the battery mounting wall 4b of the lower case 4 are provided the dust proof convex portions 4e, 4e which are slightly smaller than the cutout portions 2f, 2f of the push button 2 not so as to produce an obstacle against the motion of the push button 2 when the push button 2 is installed on the lower case 4. As a result, foreign matter cannot enter the interior of the case easily. Next, an operation of the push button 2 will be described with reference to Fig. 5. Fig. 5A is a sectional view of the push button 2 showing a state before the push button 2 is operated. The lower case 4 disposed behind the switch 3a of the substrate 3 has the ribs 4a to prevent the substrate 3 from being warped when the push button portion 2b of the push button 2 is pushed. There is a slight gap between the push button rear face 2g of the push button 2 and the supporting convex portion 4f of the lower case 4. Fig. 5B is a sectional view showing a state in which the push button 2 is being pushed. When the push button portion 2b is pushed down, the push button portion 2b is lowered vertically, so that the push button rear face 2g comes into contact with the supporting convex portion 4f. Even if this state is reached, the switch 3a is not actuated. Fig. 5C is a sectional view showing a state in which the operation of the push button 2 terminates. If the push button portion 2b is pushed further down, the push button 2 is moved as if it rotates with a contact point between the push button rear face 2g and the supporting point convex portion 4f of the lower case 4 as a fulcrum. Then, the switch pushing convex portion 2e pushes the switch 3a so that the switch 3a is turned on. If a force applied to the push button portion 2b is released, the push button portion 2b is returned to its original position by the elasticity of the arm portions 2c, 2c. In this individual call signal receiver, when the push button portion 2b is pushed, the arm portions 2c, 2c are elastically deformed with the supporting point portion 4d in contact with the fixing portion 2a as a fulcrum, so that the push button portion 2b is lowered. However, since the push button rear face 2g comes into contact with the supporting convex portion 4f of the lower case 4, the push button portion 2b acts with this contact point as a fulcrum. Thus, the side of the cutout portion 2f of the push button portion 2b is prevented from being depressed too much, so that the switch 3a can be pushed with a short stroke. At this time, the shorter a distance between the supporting point portion 4d and the supporting convex portion 4f, the more preferable because a distance between the push button portion 2b and the supporting convex portion 4f can be extended more. With such a structure, the push button 2 of the individual call signal receiver can be operated at a weak pushing force and at the same time, the individual call signal receiver can be formed in small and thin structure. Because the supporting convex portion 4f is provided on top face of the battery mounting wall 4b, a space inside the case can be effectively used.

Claims: A switch structure of an electronic device, comprising: a case (1, 4) having supporting convex portions (4f, 4f); switches (3a, 3a) mounted within said case; and a push button (2) containing arm portions (2c, 2c, 2c, 2c) elastically deformable, push button portions (2b, 2b), and a switch pushing convex portion provided on an end of a face of each said push button portion, whereby one end of each of said arm portions which is far from each said push button portion is fixed to said case, each said supporting convex portion (4f) is provided so as to contact the other end of said face of each of said push button portions (2b), during the operation of each said push button portion, and each said switch pushing convex portion actuates each said switch when the operation of each said push button portion has terminated, whereby a battery mounting chamber (4c) is provided in a region under said push button (2) as a part of said case (1, 4) and said supporting convex portions (4f, 4f) are provided on a surface of wall (4b) of said battery mounting chamber. A switch structure of an electronic device, as claimed in claim 1, characterised in that said push button (2) is fixed to said case (1, 4) by engagement between grooves (2h, 2h) provided on said push button and nails (4 g, 4g) provided on said wall (4b) of said battery mounting chamber (4c). A switch structure of an electronic device, as claimed in claim 2, characterised in that said push button (2) has arm portions (2c, 2c, 2c, 2c) and dust proof convex portions (4e, 4e) provided on said wall (4b) of said battery mounting chamber (4c) are located between said arm portions.

Inventors: YAMADA HIROSHI, YAMADA, HIROSHI
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1998
Main classification: H01H21
IPC codes: H01H21