A keyboard

Abstract: The present invention relates to a keyboard designed so that the depression of any key top (3) causes a correspon­ ding switch (2) to be opened or closed through a keay stem (10). An upper board (5) of the keyboard is provided with a plural number of key stem guide holes (8) equally distanced in both the directions of X axis and Y axis. In said upper board (5), four slip stopper guide holes (9) are provided symmetrically with respect to each key stem guide hole (8) at a right angle to each other. Further­ more, slip stoppers (13) are provided extending from the bottom of said key top (3), symmetrically with respect to the key stem (10) at 180° to each other. Said key top (3) is available in plural number of sizes, that is, in sizes with the depth of width which is integral-number times the unit size. The key top (3) of the unit size is provided with one key stem (10), whereas the key top of n-times the unit size is provided with n pieces of key stems (10). The keys (1) arranged in the manner described above are designed so that their respective directions can be altered by 90°.

Description: The present invention relates to a keyboard to be used as an input device for a computer and other electronic equipment. In a common, conventional keyboard, a number of membranes or mechanical switches are installed on a lower board at a specified pitch, whereas a number of keys are installed on an upper board disposed above the key section so as to be able to move both upward and downward freely. Depressing the key top of any one of said keys causes the corresponding switch to be opened or closed through the key stem as an integral part of the key. The key top of a standard key is square with a side length of about 18mm, but the key tops of keys for highly frequent and special use have rectangular forms or sizes, which are an integral-number times the unit size of the standard key. In a conventional keyboard, even the special key such as a rectangular key 1 is provided with only one key stem 10 that extends from about the center of its bottom just above a corresponding switch 2 as shown in Fig. 6, a front view of a key, and Fig.7, a side view of a key. This arrangement prevents each key from being replaced by keys 1 of different forms and different switches. It is necessary for any such special-form key to be depressed evenly irrespective of the point of depression on the key top 3. To meet this requirement, in the case described in Fig.6, a crank-form interlocking rod 4 is incorporated so that even when the key is depressed at a point on the right end of the key top indicated with an arrow, the other end of the key top 3 can be depressed simultaneously by means of the interclocking rod 4, thereby preventing the key from being depressed unevenly as described with the dotted line. The upper board is indictated as number 5; the lower board as number 6; and the interlocking rod as number 4. As shown in Fig.6, in the case of a keyboard wherein the switches 2 are located just under the centers of the corresponding keys 1, the sizes and locations of the individual keys are fixed at the time of the design of the keyboard, and this leads to lack of flexibility in actual use, which prevents alterations of the key size and key layout. Thus, in order for the conventional keyboard to be capable of meeting such needs of alterations, a number of and a variety of parts must be provided such as the keys, switches, upper board, lower board, interlocking rod and others, which is not only uneconomical but also causes other problems such as the increase in the number of assembly processes. EP-A-0 087 369 discloses an electronic keyboard having a base, a flexible circuit defining a plurality of switches and a plurality of key means. The base member of the electric keyboard comprises a surface having a plurality of faces, where at least one face is oriented in a different plane from, but intersecting another face. The flexible circuit is disposed on the surface faces at different levels and the keys means are disposed on the flexible circuit. The German laid-open publication DE-A-33 10 313 discloses a keyboard for increasing flexibility when the same or different sized key heads are employed. The individual keys comprise a key head with resilient elements, a guide or contact pin 3 as well as a key displacement stop and a key base for one or more keys made of drawn plastic foil. The key head is uniformly connected to the key base 5 by means of the displacement stop projection. Contact elements associated with the key heads are arranged in the key base. The first object of the present invention is to provide what is called a general-purpose keyboard capable of flexibly meeting the needs such as the alterations of the size and layout of the keys so that even the keyboards of different equipment may be used. The second object of the present invention is to provide a keyboard that permits the alterations of the locations and sizes of keys by simply replacing the keys concerned. The third object of the present invention is to reduce the number of parts as far as possible by increasing the number of common parts. In accordance with the present invention, a keyboard, which fulfills the above goals, is provided as defined in claim 1. The further objects and features of the present invention will be clarified in more detail through the following description of the embodiments. Fig.1 is a perspective view of disassembled keyboard according to an embodiment of the present invention. Fig.2 is a cross-sectional view of the keyboard shown in Fig.1. Fig.3 is a perspective view showing the back of the unit-size key according to an embodiment of the present invention. Fig.4 is a perspective view showing the back of a key whose area is 2 times that of a unit-size key Fig.5 is a perspective view showing the back of a key whose area is 4 times that of a unit-size key. Fig.6 is a partial cut-away front view of a conventional keyboard. Fig.7 is a side view of the key shown in Fig.6. An embodiment of the present invention will be explained with reference to Fig.1 or Fig.5. The upper board is indicated as the number 5, and the lower board as number 6. Said upper board 5 is provided with a number of key stem guide holes 8 at equal distances in both the directions of X-axis and Y-axis. Four rectangular slip stopper guide holes 9 are provided around each key stem guide hole 8 and are provided symmetrically thereto at a right angle to each other. That is, for example, in the case shown in Fig.1, the 1st hole 9a, the second hole 9b, the 3rd hole 9c and the 4th hole 9d in clockwise direction are of the same size, though the 1st and 3rd holes are provided as sideways disposed rectangular holes, and the 2nd and 4th holes as vertically disposed rectangular holes. Figs.3, 4 and 5 show another embodiment concering the key. For instance, Fig.3 shows a key whose key top 3 is a square with a side length of a (mm). Fig.4 shows a key whose key top is a rectangle with shorter sides having a length of a (mm) and the longer sides having a length of 2a (mm). The area is 2 times that of the square key top. Fig.5 shows a key whose key top has side lengths of 2a (mm) and the area is 4 times that of the unit-size square key top. The sizes and forms of the key tops other than that of the unit-size square key top, such as the long-form, L-form or U-form key tops, are to be determined as integral times a (mm) depending oh the individual purposes. The unit-size key 1 shown in Fig.3 is provided with a key stem 10 extending from the bottom of key top 3. A coil spring 11 for opening or closing the switch 2 on the lower board 6 is forced into the central hole of said key stem 10 as exemplified by the key stem 10 shown on the left in Fig.2. Another coil spring 12 for pushing up the key 1 is provided around the key stem 10 as exemplified by the key stem 10 on the right in Fig. 2. Slip stoppers 13 with projections 14 are provided under the key top 3, symmetrically with respect to the key stem 10 at 180° to each other. In addition, column members 15 are erected on another set of positions which are also symmetrical with respect to the key stem at 180° to each other, but said members may be omitted. The unit-size key 1 composed in the manner described above is inserted into the key stem guide hole 8 and the slip stopper guide hole 9. The orientation direction of insertion can be changed at intervals of 90°. The key 1 shown in Fig.4 has a rectangular key top whose area is 2 times that of the unit-size key as explained previously. Said key is provided with two key stems 10 at a distance equal to that of the key stem guide holes 8 and 8. Of said two key stems 10, one which is not required to press the switch 2 has a diamter smaller than that of the other, so that said key stems can move up and down smoothly even when there is slight difference between the distance of key stem guide holes 8 and that of the key stems 10. The key 1 shown in Fig.4 whose area is 2 times that of the unit-size key has two slip stoppers 13 provided for each of its key stems 10. The stoppers 13 are provided symmetrically with respect to said key stem at 180° to each other, and the column members shown in Fig.3 are not provided. The key 1 shown in Fig.5 has a square key top whose area is 4 times that of the unit-size key top. Said key is provided with four key stems 10, and one slip stopper 13 is provided for each key stem 10. Of said four key stems 10, two key stems 10 distanced at 180° to each other provided with the coil springs 11 and 12 respectively. The keys having rectangular form, L-form, U-form and other forms are also composed in the manner similar to those of the keys described above. In the keyboard composed in the manner described in the foregoing, the keys 1 of various forms can be inserted into the corresponding key stem guide hole 8 and slip stopper guide hole 9 so that said keys can be installed through the engagement between the slip stopper 13 and the slip stopper guide hole 9. As described in the foregoing, in the case of the keyboard according to the present invention, the key stem guide holes on the upper board are pitched at equal distances in both X-axis and Y-axis directions, and the lengths of both the shorter sides and longer sides of the keys are maintained at integral ratios with respect to the unit length, so that the layout of the keys can be set freely. Furthermore, the keyboard according to the present invention permits the location of the keys already installed to be altered without disassembling the keyboard by simply replacing the keys from above the keyboard.

Claims: A keyboard, wherein the keys (1) are installed so that the depression on the key top (3) of any one of the keys (1) can cause the corresponding switch (2) on a lower board (6) to be opened or closed through a key stem (10) which is an integral part of the key (1), featuring key stem guide holes (8) provided at equal intervals in both X-axis and Y-axis directions, slip stopper guide holes (9) provided symmetrically with respect to each key stem guide hole (8) and slip stoppers (13) provided to extend from the bottom of the key top (3) symmetrically with respect to said key stem (10) at 180° to each other so that said slip stopper (13) can engage with said slip stopper guide holes (9), characterized in that the keys (1) are installed on an upper board (5), and that both the key stem guide holes (8) and the slip stopper guide holes (9) are provided on said upper board (5), wherein four slip stopper guide holes (9) are provided symmetrically with respect to each key stem guide hole (8) so that each slip stopper guide hole (9) forms the corner of an imaginary rectangle or square, respectively. A keyboard, according to claim 1, wherein a square key top (3) with each side defining a unit length is provided with one key stem (10) extending from the center of the bottom of the key top (3) and two slip stoppers (13) are provided around the circumference of the key stem (10). A keyboard, according to claim 1, wherein the key top (3) of each key (1) which is provided with one key stem (10) defines an unit area, wherein each key top (3) whose area is n-times the unit area is provided with n pieces of key stems (10), which extend from the bottom of the key top (3) and are disposed at equal distances to those of the key stem guide holes (8) wherein n is an integer and wherein the diameters of the key stems (10) which are not required to press a switch (2) are each slightly smaller than that of the key stem which is required to press the said switch (2). A keyboard, according to any of the claims 1 to 3, wherein all the slip stopper guide holes (9) are each rectangular and of the same size, wherein the said holes (9) are disposed around each key stem guide hole (8) so that the first and third slip stopper guide holes (9a, 9c) are oriented perpendicular to the second and fourth slip stopper guide holes (9b, 9d).

Inventors: YOSHIDA HARUO, YOSHIDA, HARUO
Applicants: SMK KK, SMK CO., LTD.
Application year: 1987
Main classification: H01H13
IPC codes: H01H13, H01H3, H01H11