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(11) | EP 0 181 130 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Push-button switch structure for telephone or the like |
| (57) A push-button switch structure for a telephone or like equipment includes a plurality
of push-buttons which respectively are received in openings of an upper casing of
the equipment. An elastic sheet adapted to support the push-buttons is tightly pressed
against the upper casing by a frame member, thereby maintaining the interior of the
casing liquid-tight. A pin-like projection extends downwardly from the center of and
inside each of the push-buttons. which protrudes upwardly beyond the upper casing,
while a generally U-shaped projection extends upwardly from that portion of the sheet
which is aligned with an actuator of each switch body to be mated with the pin-like
projection. |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a push button structure for push-button switches which are used with an electronic equipment such as a telephone.
[0002] In the art of telephones, various kinds of switches have been proposed for particular applications. For example, a push-button switch arrangement which fulfills the function of a dial comprises a plurality of push-buttons which are received in a plurality of openings formed through the outer surface of the casing of a telephone. The push-buttons each being engraved with a numeral or like symbol are manipulatable from outside the telephone casing. In another example, the outer surface of a telephone casing is partly covered with an elastic sheet, or pad, and switches are arranged below the elastic sheet.
[0003] The problem with the push-buttons which are received in the openings is that drops of water and other impurities easily enter the casing of the telephone through the outer surface of the telephone, bringing about various problems in practical use. Meanwhile, the elastic sheet scheme, although it offers a liquid-tight structure, renders the manipulation awkward due to the sheet which constitutes the outer surface of the telephone casing and, thereby, often invites erroneous manipulations. In addition, such a sheet imposes limitations on the design of a telephone.
SUMMARY OF THE INVENTION
[0004] It is therefore an object of the present invention to provide a reliable push-button switch structure for a telephone or the like which prevents waterdrops and other impurities from entering the equipment
[0005] It is another object of the present invention to provide a push-button switch structure for a telephone or the like which is easy and efficient to manipulate.
[0006] It is another object of the present invention to provide a push-button switch structure for a telephone or the like which enhances freedom of design.
[0007] It is another object of the present invention to provide a push-button switch structure for a telephone or the like which is easy to assemble.
[0008] It is another object of the present invention to provide a generally improved push-button switch structure for a telephone or the like.
[0009] A push-button switch structure for use in an electronic equipment of the present invention comprises a casing made up of an upper casing part and a lower casing part which are assembled in an integral configuration, the upper casing being formed with a plurality of through openings, a plurality of push-buttons which respectively are received in the through openings to protrude outwardly beyond the upper casing, an elastic sheet member formed with retaining means integrally therewith for retaining the push-buttons such that each of the push-buttons is movable through the associated through opening when manipulated from outside, and a dealing member liquid-tightly isolating an interior of the casing from the outside by pressing peripheral portions of the elastic sheet member tightly against peripheral portions of an underside of the upper casing where the through openings are positioned.
[0010] In accordance with the present invention, a push-button switch structure for a telephone or like equipment includes a plurality of push-buttons which respectively are received in openings of an upper casing of the equipment. An elastic sheet adaped to support the push-buttons is tightly pressed against the upper casing by a frame member, thereby maintaining the interior of the casing liquid-tight. A pin-like projection extends downwardly from the center of and inside each of the push-buttons, which protrudes upwardly beyond the upper casing, while a generally U-shaped projection extends upwardly from that portion of the sheet which is aligned with an actuator of each switch body to be mated with the pin-like projection.
[0011] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompaying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]
Figs. 1-3 are fragmentary vertical sections each showing a telephone to which a particular example of various prior art push-button switch structures is applied;
Fig. 4 is an exploded perspective view of a telephone to which a push-button switch structure embodying the present invention is applied;
Fig. 5 is a fragmentary sectional side elevation of the telephone shown in Fig. 4; and
Fig. 6 is a perspective view demonstrating engagement of a push button and an elastic sheet in accordance with the embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] While the push-button switch structure for a telephone or the like of the present invention is susceptible of numerous physical embodiments, depending upon the environment and requirements of use, a substantial number of the herein shown and described embodiment have been made, tested and used, and all have performed in an eminently satisfactory manner.
[0014] To better understand the present invention, a brief reference will be made to some examples of prior art push-button switch structures for a telephone and others, shown in Figs. 1-3.
[0015] Referring to Fig. 1, a push-button switch structure which is installed in a telephone or the like is shown. A push-button mechanism, generally 10, serves the dialing function and comprises a plurality of push-buttons 12 which are integral with a switch body 14. A telephone 16 includes an upper casing 16a which constitutes an operating section, and a lower casing 16b. The upper casing 16a is formed with a plurality of openings 18 therethrough. The push-button mechanism 10 is fixed in place by a support plate 20 with the push-buttons 12 inserted into the openings 18 from below. The problem with this kind of structure is that drops of water are apt to enter the telephone through the clearances between the edges of the openings 18 and those of the push-buttons 12, often inviting malfunctions.
[0016] Referring to Fig. 2, a push-button mechanism 22 comprises a plurality of push-buttons 24 each of which is operatively mounted in a switch body 26 which in turn is rigidly mounted on a support plate 28. Meanwhile, the upper casing 16a of the telephone 16 is partly removed and has the removed area covered with an elastic sheet, or pad, 30. The mechanism 22 is disposed in the telephone 16 below the elastic pad 30 in such a manner that the push-buttons 24 make light contact with the underside of the pad 30. Although such a strcuture is superior to the structure of Fig. 1 concerning liquid-tightness, the operationability is poor because an individual has to manipulate the push-buttons 24 from above the pad 30.
[0017] Referring to Fig. 3, a push-button mechanism 32 comprises push buttons 34 which are similar to those of Fig. 1 and a pad 36 which is similar to that of Fig. 2, the push-buttons 34 and the pad 36 being formed integrally with each other. The upper casing 16a of the telephone 16 is provided with a plurality of openings 38, while a frame member 40 which is dimensioned large enough to surround the openings 38 is fixed to the upper casing 16a inside the telephone 12. The integral push buttons 34 and pad 36 are rigidly supported by the upper casing 16a and the frame member 40. Disposed below and aligned with the push buttons 34 are the switch bodies 26 and actuators 42 which respectively are associated with the switch bodies 26. The switch bodies 26 and actuators 42 are mounted on a support plate 44 such that the actuators 42 remain in light contact with the underside of their associated push-buttons 34. The dilemmatic situation with this kind of structure is that while each of the push-buttons 34 needs to be hard enough to promote efficient manipulation, the pad 40 needs to be elastic enough for the actuators 42 to be depressed.
[0018] The present invention constitutes a solution to the various problems particular to the prior art push-button switch structures as discussed above. Particularly, the present invention constitutes an improvement over the structure of Fig. 3 and allows the push buttons 34 and the pad 36 to be formed independently of each other and assembled together afterwards.
[0019] A push-button switch structure embodying the present invention will be described with reference to Figs. 4-6. In Figs. 4-6, the same or similar structural elements as those shown in Fig. 3 are designated by like reference numerals.
[0020] The structure of the present invention, generally 46, shares the same construction with the structure of Fig. 3 concerning the upper casing 16a and lower casing 16b of the telephone 16, the frame 40, the support plate 44, the switch bodies 26 and their associated actuators 42 and, therefore, description of such parts and elements will be omitted. As shown in Figs. 5 and 6, the structure 46 comprises a plurality of push-buttons 48 each of which is provided with a pin-like projection 50 at the center of its interior and inserted into a corresponding one of the openings 38 of the upper casing 16a from below to extend upwardly beyond the upper casing 16a. Meanwhile, a sheet 52 which is made of rubber or like elastic material is provided with a plurality of generally U-shaped projections 54 on its upper surface, the projections 54 respectively being associated with the projections 50 of the push-buttons 48. A plurality of lugs 56 extend downwardly from the lower surface of the sheet 52 to face the actuators 42 of the switch bodies 26. The U-shaped projections 54 on the upper surface of the sheet 52 respctively are mated with the pin-like projections 50 of the push-buttons 48, while the lugs 56 on the lower surface of the sheet 52 are located close to, or substantially in contact with, the actuators 42 of the switch bodies 26.
[0021] In the construction shown in Figs. 5 and 6, the sheet 52 is tightly pressed along its edges by stepped portions 40a of the frame member 40 against projections 58 which extend in the peripheral portions of the underside of the upper casing 16a. Such insures liquid-tightness and prevents drops of water and others which would damage the switch bodies 26 and others from penetrating into the telephone through the upper casing 16 a. In addition, the configuration of the push buttons 48 which does not have to be sheet-like frees the telephone from design limitations and promotes easy and efficient manipulation.
[0022] Further, in this particular embodiment, electrical circuit elements of the telephone 16 may be mounted on the lower casing 16b and the push-buttons 48 and others of the operating section of the telephone 16, on the upper casing 16a. Hence, the subassembly associated with the upper casing 16a and that associated with the lower casing 16b can be produced independently of each other.
1. A push-button switch structure for use in an electronic equipment, comprising:
(a.) a casing made up of an upper casing part and a lower casing part which are assembled in an integral configuration, said upper casing being formed with a plurality of through openings;
(b) a plurality of push-buttons which respectively are received in said through openings to protrude outwardly beyond the upper casing;
(c) an elastic sheet member formed with retaining means integrally therewith for retaining the push-buttons such that each of said push-buttons is movable through the associated through opening when manipulated from outside; and
(d) a sealing member liquid-tightly isolating an interior of the casing from the ouside by pressing peripheral portions of said elastic sheet member tightly against peripheral portions of an underside of the upper casing where the through openings are positioned.
2. A push-button switch structure as claimed in claim 1, wherein each of the push-buttons
comprises a pin-like projection which extends from a center of and inside said push-button,
each of retaining means of the sheet member comprising a generally U-shaped projection
which extends from an upper surface of the sheet member to be mated with said pin-like
projection.
3. A push-button switch structure as claimed in claim 1, wherein the peripheral portions
of the underside of the upper casing comprise projections, the sealing member comprising
a frame member having stepped portions which abut against said projections, the peripheral
portions of the sheet member being compressed between said projections of the upper
casing and said stepped portions of the frame member.
4. A push-button switch structure as claimed in claim 2, wherein the sheet member
comprises lugs which extend from a lower surface of the sheet member in alignment
with the U-shaped projections.
5. A push-button switch structure as claimed in claim 4, wherein switch bodies each
having an actuator which is to be depressed by any of the lugs of the sheet member
associated with said actuator are disposed in the casing.