DE9317990U1 - Button structure - Google Patents

Description

GLAWE, DELFS, MOLL & PARTNERS - .-. ..,.,,,,...»_.,_ .

I . JajGCLASSINE REPRESENTATIVE AT THE EUROPEAN PATENT OFFICE

RICHARD GLAWE, Dr.-lng. (1952-1985)

KLAUS DELFS, Dipl.-lng., Hamburg

WALTER MOLL, Dipl.-Phys. Dr. rer. nat, Munich

ULRICH MENGDEHL, Dipl.-Chem. Dr. rer. nat., Hamburg

HEINRICH NIEBUHR, Dipl.-Phys. Dr. phil. habil., Hamburg

ULRICH GLAWE, Dipl.-Phys. Dr. rer. nat., Munich

Chicony Electronics Co., Ltd., Bernhardmerkau,Dipl.-Phys.,Munich

Taipei, Taiwan, R. &Ogr;. C. PO Box 26 01 62 PO Box 13 03 ₉₁

80058 Munich 20103 Hamburg

Liebherrstrasse 20 Rothenbaumchaussee

80538 Munich 20148 Hamburg

Tel. {089) 22 46 65 Tel. (040) 4 10 20

Fax (089) 22 39 38 Fax (040) 45 89

Tel. 5 22 505 Tel. 17 403 156

HAMBURG &rgr; 15762/93 N/kk (#130)

Key structure This invention relates to a key structure.

The keyboard of a computer system serves as an input device that consists of a row of keys. A key structure is activated to trigger a specific input signal as soon as any key in this keyboard row is pressed. Various well-known types of key structure will be explained in more detail here.

Fig. 4 is an exploded view of a key assembly according to its conventional design. This key assembly generally consists of a key cap, a key base and a rubber cone. The key cap is attached to the key base by its base hooks located on opposite sides. The sound when the keys are pressed is caused by the vibration when the key cap is pressed down and immediately afterwards raised to its original position by the rubber cone.

Fig. 5 to 7 show another key structure according to its conventional design. This structure also consists of a rubber cone, a key base and a key cap. The key cap consists of a lower piston with

Dresdner Bank AG Hamburg 04*030 448 OCf JBLZ200 800 00)· PWätgiro Hamburg 1476 07-200 (BLZ 200 100 20)

square cross-section, which is inserted into a square opening in the middle of the key base. The square bottom piston of the key cap has four longitudinal ribs arranged along its four edges, as well as two oppositely arranged spring strips, which are arranged on two opposite sides and are each bent outwards. The key cap is fixed thanks to the engagement of the spring strips in two oppositely arranged notches located on the underside of the key base. The function of this key structure is, however, unsatisfactory. During assembly, the square bottom piston in the key cap can accidentally be inserted into the square opening in the middle of the key base the wrong way round. The spring force of the spring strips must be precisely controlled so that the key cap can be moved vertically without it coming loose from the key base and falling off. However, it is not easy to be able to precisely control the spring force of the spring strips. Since the top edge of the square hole in the center is formed by a spring strip at an acute angle and the bottom edge of the plunger of the key cap is a right angle, it is difficult to insert the plunger in the key cap into the right-angled hole in the center of the key base during assembly. Furthermore, the four longitudinal ribs that serve to guide the movement of the plunger into the square hole in the center of the key base cannot move the key cap properly. Therefore, the key cap generates a vibration when the key is pressed and returned to its original position by the rubber cone.

The object of the invention is to create a key structure that is stable and durable in use and produces hardly any noise during use.

Another object of the invention, taking the above circumstances into account, is to provide a key structure that does not cause any vibration during operation. Another object of the present invention is to provide a keyboard whose long-term operation does not cause pain in the fingers and hands. Still another object of this invention is to provide a keyboard that significantly reduces the noise during operation. Another object is to provide a keyboard that does not involve high costs in manufacturing.

According to the preferred embodiment of the invention, the key assembly has an internal piston that is inserted into an opening in the key base and causes a circuit located inside a membrane to be triggered when the rubber cone is pressed. The piston has four pairs of elongated ribs located in the four edges on the inner wall of the key base. Two spring hooks are attached to the edges on the underside of the key base. Each spring hook has a spring that is attached to two sides at a distance from the piston, a hook part on the underside of the hook and two beveled edges. These two beveled edges are connected on two sides between the hook part and the hook that serves to guide the hook part into the hooking position. This causes no noise when the piston moves. Since the piston is square, it cannot be inserted into the rectangular projection the wrong way round during assembly of the key assembly. The inner upper edge of the rectangular projection of the key base is slightly rounded. Thanks to this design, the key cap can be easily inserted into the rectangular projection of the key base. Since the piston of the key cap is brought into contact with the smooth inner wall in the rectangular projection of the key base with its four pairs of longitudinal ribs, the contact area between the piston and the projection is reduced,

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thereby significantly reducing friction. The gaps on the piston on two opposite sides of the spring hooks allow the movement of the hooks to be carried out without noise from the piston when the respective key is pressed. Therefore, the key cap moves stably when it is pressed down by the operation. Since the rounded edges are respectively on the spring hooks and serve to guide the hook parts into the respective hooking position with the respective edges of the key base, the piston will not cause vibration during the upward movement, which significantly reduces noise. Furthermore, the rubber cone according to this invention is also better designed than those in the conventional structure. After being pressed down, the rubber cone of the invention can easily return to its original shape. Fig. 3 shows the difference in spring force between the rubber cone according to this invention and the rubber cone of the conventional structure. The curve line 0 of the rubber cone according to this invention is smoother than the curve line 0' of a rubber cone in a conventional structure.

The invention is described below using an advantageous embodiment with reference to the accompanying drawings for example.

Fig.* 1 is an exploded view of a key assembly of a preferred embodiment of this invention;

Fig. 2 shows the key structure shown in Fig. 1 in section;

Fig. 3 is a comparison table showing the relationship between the impact of the key cap and the spring force of the rubber cone according to this invention and that according to the conventional embodiment;

Fig. 4 shows an exploded view of a conventional

key structure;

Fig. 5 is an exploded view of another conventional key structure;

Fig. 6 shows the piston of a key cap of a key structure shown in Fig. 5, which swings after an impact; and

Fig. 7 shows the key structure shown in Fig. 5 in section.

As shown in Figs. 1 and 2, a key assembly according to the preferred embodiment of this invention generally consists of a keycap 1, a keybase 2, a frame 3, a rubber cone 4 and a diaphragm 5. The diaphragm 5 is located on the bottom. The frame 3 is located at a distance above the diaphragm 5 and supports the keybase. The keycap is mounted on the keybase 2. The rubber cone 4 is held on the diaphragm 5 under the frame 3 in alignment with the keycap 1.

The keycap 1 is rectangular. The top of the keycap 1 is curved inwards for better touching with the fingers. A rectangular piston 11 extends downwards from the keycap 1. This piston 11 consists of four pairs of elongated guide ribs, each arranged around the edges of this piston, two symmetrical longitudinal spaces 111 on its two opposite sides, two spring hooks 112 on its two opposite sides - located between the symmetrical longitudinal spaces 111 - and a lower edge 115 on its underside. Each spring hook 112 has two bevelled edges 113, which are arranged on both sides between the spring and its hook end.

The key base 2 consists of a hollow, rectangular projection 21 with a smooth inner wall 212 on all its

four sides and a slightly rounded guide edge 211 around the smooth inner sides 212 on its upper side. This rounded guide edge 211 serves to insert the right-angled piston 11 of the key cap 1 into the right-angled protrusion 2. The key base 2 also has two lower edges 213, which each engage with the spring hook 112 of the key cap 1.

The frame 3 is arranged at a distance above the membrane 4 for supporting the key base 2. The frame 3 has an opening (not shown) corresponding to the rectangular projection 21 so that the rectangular piston 11 of the key cap 1 can be inserted therein.

The rubber cone 4 consists of a small upper ring 41 fixed to the bottom, a large lower ring 44, a horn-like conical wall 43 between the upper ring 41 and the lower ring 44 and which narrows upwards towards the upper ring 41, and a stool 42 at the bottom of the upper ring 41 in the middle inside the bevelled wall 43.

The membrane 5 consists of an upper switching layer 51, which is provided with a silver contact 511, a lower switching layer 52, which has a silver contact 512, and an intermediate insulating layer 53, which is provided with an opening 54 and is located between the contacts 511, 512.

As shown in Fig. 6, the piston 11 of the key cap 1 is guided into the right-angled projection 21 by the slightly rounded guide edge 211 of the key base 2. After insertion, the lower end of the piston 11 hits the upper ring 41 of the rubber cone 4 with its edge 115 and is thus held in place. The lower edge is held above the stool 42. The spring hooks 112 are each held in place by the lower edge 213. Therefore, by pressing down the

Keycap 1, the upper ring 41 on the rubber cone 4 is pressed down by the lower end of the piston 11. As soon as the rubber cone 4 is pressed down by the lower end of the piston 11 with the stool, it comes into contact with the contact 511 located on the upper switching layer 51. The stool 42, when pressed down, enters the opening 54 located in the intermediate insulating layer 53, and then comes into contact with the contact 512 of the lower switching layer 52. This transmits a specific input signal in the circuit in the membrane 5 from the keyboard to the computer. As soon as the keycap 1 is released again, the rubber cone 4 immediately returns to its original shape, so that it moves the keycap 1 back up to its original position. During the upward movement of the piston 11, the spring hooks 112 are guided by the respective bevelled edges 113 until they again hit the edge 113 and are held by it. In this way, no noise is caused.

The invention can be summarized as follows. The key structure consists of a key cap which has a piston which is inserted through an opening in the key base and, when pressed down, presses on a gununi cone of this key cap. This triggers a signal from the circuit in a membrane. The piston consists of four pairs of elongated ribs, each of which is arranged on its sides at a distance from one another and at the edges of the smooth inner wall of the key base. Two spring hooks are held by the edges on the underside of the key base. Each spring hook has a hook which is delimited on both sides by gaps at a distance from the piston. A hook part is located on the underside of the hook. Two beveled edges are connected on both sides between the hook part and the hook so that the hook part can be guided into the hooked position after each depression of the piston without causing noise.

Claims (5)

· · I Protection claims 1. Key structure, characterized in that it comprises: a membrane (5) consisting of a lower switching layer (52) with a first contact (512), an upper switching layer (51) with a second contact (511) which is arranged at a distance above the first contact (512), and an intermediate insulating layer (53) with an opening (54) between the first and second contacts; a rubber cone (4) consisting of a hollow frustoconical wall (43) located on the membrane (5), an upper ring (41) on top of the conical wall (43), and a stool (42) located inside the conical wall (43) below the upper ring (41) and at a distance above the second contact (511); a frame (3) arranged at a distance above the rubber cone (4) and provided with an opening which corresponds to the upper ring (41) on the rubber cone (4); a key base (2) having a hollow and rectangular projection (21) which, with its inner walls (212), defines an opening which is in communication with the opening in the frame (3) and with the upper ring (41) on the rubber cone (4), wherein the key base (2) further comprises two lower edges (213) which are located on its underside on two opposite sides; and a key cap (1) whose rectangular lower piston (11) is inserted through the opening in the key base (2) and rests against the upper ring (41) of the rubber cone (4), the lower piston (11) having two symmetrical pairs of elongated spaces (111) on its two opposite sides and two opposite sides spring hooks (112) located between each pair of elongated spaces (111) which are held by the lower edge (212) on the underside of the key base (2). 2. Key structure according to claim 1, characterized in that the surface of the key cap (1) is bent inwards for better contact with the fingers. 3. Key assembly according to claim 1 or 2, characterized in that the rectangular lower piston (11) of the key cap (1) has four pairs of elongated ribs each located around its four edges and in contact with the inner wall of the hollow, rectangular projection (21) of the key base (2). 4. Key structure according to one of claims 1 to 3, characterized in that the inner wall of the hollow rectangular projection (21) of the key base (2) is formed from four smooth planes around the opening of this hollow, rectangular projection (21) and slightly rounded guide edges (211) are provided around this opening. 5. Key structure according to one of claims 1 to 4, characterized in that each spring hook (112) of the rectangular lower piston (11) of the key cap (1) consists of a spring, a hook part extended downwards from this spring and two bevelled edges (113) which are arranged on both sides between the spring and the hook part.