CN218676875U - Key structure, long key assembly and key device - Google Patents

Abstract

The utility model relates to a keyboard button technical field provides a key structure, long key assembly and button device, this key structure includes the base, upper cover and axial structure, axial structure includes the main part, the extension, adaptation portion and a plurality of balancing portion, one side of main part is located to the extension, the opposite side of main part is located to adaptation portion, the same one side of main part is located with adaptation portion to each balancing portion, and each balancing portion is around setting up in adaptation portion, the upper cover is opened and is equipped with the through-hole structure that is used for spacing balancing portion, so that the relative institute upper cover of axial structure steadily moves telescopically. The application discloses a button structure can once be the die sinking and make and obtain axle construction, has saved the installation of balancing pole and support and to its installation space who reserves, and like this, the structure of this button structure is simpler, and is also easy with the assembly process of key cap.

Description

Key structure, long key assembly and key device

Technical Field

The utility model relates to a keyboard button technical field especially provides a button structure, have this button structure's long key assembly and have this button structure's button device.

Background

At present, keyboards have been widely used in various fields, wherein the hand feeling of the keys is also a concern of users.

Especially for longer keys such as left SHIFT, right SHIFT, ENTER, BACKSPACE, etc. In the use, in order to prevent that long button from pushing down the in-process and taking place unbalanced condition, can set up extra balancing unit such as balancing pole or satellite axle usually, balancing unit generally includes the balanced body of rod and support etc. add the balancing pole structure and not only increase die sinking expense and cost, simultaneously, also can lead to the system assembly complicated, produce the abnormal sound easily, press the card and wade the scheduling problem, be unfavorable for the dismouting and to simplification development.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application aims to provide a key structure and aims to solve the problems that the key structure in the existing key device is complex and is not easy to disassemble and assemble.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:

in a first aspect, an embodiment of the present application provides a key structure, including a base, an upper cover covering the base, and a shaft structure penetrating through the upper cover and capable of moving telescopically relative to the upper cover, where the shaft structure includes a main body portion, an extension portion, an adaptation portion, and a plurality of balance portions, the extension portion is disposed on one side of the main body portion and adapted to the base, the adaptation portion is disposed on the other side of the main body portion and adapted to a key cap, each balance portion and the adaptation portion are disposed on the same side of the main body portion, and each balance portion is disposed around the adaptation portion; the upper cover is provided with a through hole structure used for limiting the balance part, so that the shaft structure can stably move in a telescopic mode relative to the upper cover.

The beneficial effects of the embodiment of the application are as follows: the application provides a button structure, set up a plurality of balancing portions at the epaxial structure, and, each balancing portion directly sets up on the main part of axial structure, compare in traditional button structure, balancing pole and support have been saved, in the assembly, the key cap directly packs into the axial structure on, and be connected with adaptation portion looks adaptation, and simultaneously, the through-hole structure looks adaptation of each balancing portion and upper cover, promptly and the upper cover between the junction more, further increase the stability that the axial structure pushed down the process, finally, the key cap can steadily go up and down relative button structure, feel better. In conclusion, the key structure can be manufactured into the shaft structure through one-time die sinking, and the mounting of the balance rod and the support and the reserved mounting space of the balance rod and the support are omitted, so that the structure of the key structure is simpler, and the key structure is easy to assemble with a keycap.

In one embodiment, each of the balancing portions is symmetrically disposed on the main body portion with respect to a central axis of the fitting portion.

In one embodiment, the key structure further includes a guiding structure, and the guiding structure includes a guiding portion disposed on the balancing portion and a guiding adapting portion disposed on the upper cover and adapted to the guiding portion.

In one embodiment, the balancing part comprises a first sub-part arranged on the main body part and a second sub-part arranged on the first sub-part and facing away from the fitting part, and the second sub-part is fittingly connected with the keycap.

In one embodiment, the second sub-portion defines a groove structure adapted to the key cap; alternatively, the first and second electrodes may be,

the second sub-portion is provided with a groove structure, and a sleeve matched with the keycap is arranged in the groove structure.

In one embodiment, one end of the second sub-portion is integrally formed with one end of the first sub-portion.

In one embodiment, the second sub-portion and the first sub-portion are separately disposed, and one end of the second sub-portion is detachably connected to one end of the first sub-portion.

In a second aspect, an embodiment of the present application further provides a long key assembly, which includes a bottom plate, a key cap, and the key structure described above, wherein a base of the key structure is fixed on the bottom plate, the key cap is adapted to the adapting portion of the key structure, and each balancing portion of the key structure extends along a length direction of the key cap.

The beneficial effects of the embodiment of the application are as follows: the application provides a long button subassembly, on the basis that has above-mentioned button structure, this long button subassembly's overall structure is simpler, changes in the assembly.

In one embodiment, the upper cover of the key structure is fixedly connected to the bottom plate.

In a third aspect, an embodiment of the present application further provides a key device, including the above key structure.

The beneficial effects of the embodiment of the application are as follows: the application provides a button device, on the basis that has above-mentioned button structure, the dismouting of being convenient for, and the cost is lower.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a key structure according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of an axle structure of a key structure according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a key structure according to a second embodiment of the present invention;

fig. 4 is a schematic structural diagram of an axial structure of a key structure according to a second embodiment of the present invention;

fig. 5 is a schematic structural diagram of an axial structure of a key structure provided in the third embodiment of the present invention;

fig. 6 is an exploded view of a long key assembly according to an embodiment of the present invention;

fig. 7 is an exploded view of a long key assembly according to a second embodiment of the present invention;

fig. 8 is a schematic structural diagram of a key cap of a long key assembly according to an embodiment of the present invention.

Wherein, in the figures, the various reference numbers:

100. a key structure;

10. a base; 20. an upper cover; 20a, a via structure; 30. a shaft structure; 31. a main body portion; 32. an extension portion; 33. an adapting section; 34. a balancing section; 35. a guide structure; 351. a guide portion; 352. a guide fitting portion; 341. a first sub-section; 342. a second sub-section; 34a, a slot structure; 34b, a sleeve; 361. a clamping hole; 362. a clamping arm;

200. a long key assembly; 201. a base plate; 202. a keycap; 203. a cap body; 204. and (6) mounting the column.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Traditional key structure is when fitting with big key cap, except the axis body, still need be being provided with balanced structure, this balanced structure is including setting up two satellite axles in the relative both sides of axis body and the balanced strip of connecting these two satellite axles, like this, big key cap then has three position of being connected with this key structure, promptly, is connected with axis body and two satellite axles respectively. However, the conventional key structure has a complicated overall structure due to the addition of the satellite axis and the balance bar, and is complicated to assemble. In view of the above problems, the embodiments of the present application provide the following solutions:

referring to fig. 1 and 3, a key structure 100 of the present application includes a base 10, an upper cover 20, and a shaft structure 30. The base 10 and the cover 20 are adapted to be coupled to a base plate of a key device, and the shaft structure 30 is adapted to be coupled to a key cap 202.

Specifically, the base 10 is buckled with the upper cover 20, and the shaft structure 30 penetrates through the upper cover 20 and can move telescopically relative to the upper cover 20, so as to meet the pressing requirement of the key cap 202. The shaft structure 30 includes a main body portion 31, an extension portion 32, an adapter portion 33, and a plurality of balance portions 34.

Here, the main body 31 mainly plays a bearing role, and the extension portion 32, the fitting portion 33, and the balance portions 34 are connected.

The extension portion 32 is disposed at one side of the main body portion 31 and is adapted to the base 10, wherein the extension portion 32 is a rod or a similar rod structure and is adapted to the base 10 to prevent the shaft structure 30 from coming off the base 10.

The fitting portion 33 is disposed on the other side of the main body portion 31 and is fitted with the key cap 202, where the shape and structure of the fitting portion 33 are not limited so as to be fittingly connected with the key cap 202, for example, the key cap 202 is provided with a mounting post 204, the fitting portion 33 is a mounting sleeve fitted with the mounting post 204, and the mounting post 204 is inserted into the corresponding mounting sleeve. And, the number of the fitting portions 33 is also adjusted more practically.

Illustratively, the number of the fitting parts 33 is one, then, the fitting parts 33 are located at the central position of the main body part 31, such as the central point, or the geometric center, or the symmetric center, etc., and correspond to the extension parts 32, i.e., at this time, the extension parts 32 are also located at the central position of the main body part 31, so as to achieve smooth extension and retraction of the shaft structure 30 relative to the upper cover 20. And, each balance portion 34 is disposed around the fitting portion 33, so that the coupling position between the shaft structure 30 and the upper cover 20 is increased and the stability is improved.

Of course, in other embodiments, when facing a keycap 202 with a longer length, the number of the adapting portions 32 may be increased, so that the number of the direct connection positions between the shaft structure 30 and the keycap 202 is increased, so that the force transmission between the keycap 202 and the shaft structure 30 is more balanced, and a more pressing feeling is obtained.

Each balance part 34 and the adapting part 33 are arranged on the same side of the main body part 31, each balance part 34 is arranged around the adapting part 33, and the upper cover 20 is provided with a through hole structure 20a for limiting the balance part 34, so that the shaft structure 30 can stably extend and retract relative to the upper cover 20. It can be understood that the addition of the balance portion 34 improves the connection position between the shaft structure 30 and the upper cover 20, so that the shaft structure 30 is more stable in the lifting process relative to the upper cover 20, and especially when the size of the key cap 202 is too large, a user can ensure that the key cap does not deviate under the condition of uncertainty of pressing the position of the key cap 202, and then the shaft structure 30 is lifted smoothly relative to the upper cover 20. Here, the smooth pressing does not mean that the key cap 202 does not move with the fitting part 33 in an offset manner, but the probability of the movement in an offset manner is reduced, so that there is a smooth probability that a high probability occurs in the pressing of the key cap 202.

Specifically, for example, when the key cap 202 is a space key cap, a user often presses the opposite ends of the space key cap during use, so that the conventional key structure is prone to cause the space key cap to incline during pressing, which leads to a pressing and jamming condition, and after the balance part 34 is additionally provided, the number of connection positions between the outer wall of the shaft structure 30 and the inner wall of the through hole structure 20a of the upper cover 20 is increased, so that the shaft structure 30 is more moved relative to the upper cover 20.

Therefore, the shape and structure of each balance portion 34 and the position of each balance portion 34 on the main body 31 are not limited, so that the key cap 202 can be smoothly pressed down.

Illustratively, the balance portion 34 is a block structure having a circumferential side wall that matches a hole wall of the through-hole structure 20a of the upper cover 20. Alternatively, the balance portion 34 is a contoured structure having a circumferential side wall that is fitted with the hole wall of the through-hole structure 20a of the upper cover 20.

Illustratively, the shape and structure of each balance portion 34 are the same, and the adapted periphery is symmetrically disposed with the central axis of the adapted portion 33 as the symmetric center, so that the adapted portion 33 is matched with the hole wall of the through hole structure 20a of the upper cover 20 to be balanced in force. Alternatively, each balance portion 34 may be disposed on the main body 31 in an asymmetric manner, and only the force balance between the adapting portion 33 and the hole wall of the through hole structure 20a of the upper cover 20 in the adapting connection process needs to be achieved, for example, the distances from the center of gravity of each balance portion 34 to the central axis of the adapting portion 33 are equal, and the weights of each balance portion 34 are the same.

The application provides a key structure 100, set up a plurality of balancing parts 34 on axial structure 30, and, each balancing part 34 directly sets up on axial structure 30's the balancing part 34, compare in traditional key structure 100, balancing pole and support have been saved, in the assembly, key cap 202 directly packs into on axial structure 30, and with adaptation portion 33 looks adaptation connection, simultaneously, each balancing part 34 and the through-hole structure 20a looks adaptation of upper cover 20, promptly with the position of being connected between the upper cover 20 more, further increase the stability that axial structure 30 pushed down the process, finally, key cap 202 can steadily rise to descend and feel better relative key structure 100. In summary, the key structure 100 of the present application can be manufactured to obtain the shaft structure 30 by opening the mold once, and the installation of the balance bar and the bracket and the reserved installation space thereof are omitted, so that the structure of the key structure 100 is simpler, and the assembly process with the key cap 202 is also easy.

Specifically, referring to fig. 1 and 3, in one embodiment, each of the balance portions 34 is symmetrically disposed on the main body portion 31 with the central axis of the fitting portion 33 as the center. It can be understood that the balance parts 34 are identical in shape and structure and have the same weight, so that the central axis of the fitting part 33 of the shaft structure 30 is the force balance center of the whole shaft structure 30, and thus, when the force balance center of the key cap 202 is coincident with the central axis of the fitting part 33, the key cap 202 is more stable during the pressing down process.

For example, as shown in fig. 1, in the long key cap 202 such as a space key, the balance parts 34 and the fitting parts 33 are arranged in a line along the length direction of the long key cap 202. Thus, the force bearing area of each balance part 34 is the same as that of the inner wall of the long key cap 202. Or, the balancing parts 34 are arranged in a cross shape with the central axis of the adapting part 33 as the center, and similarly, the long keycap 202 can be stressed in a balanced manner in the pressing process.

Or, for example, when the key cap is large, for example, a key cap for carriage return or a key cap for blank space, the number of the balance parts 34 is more than two, and in this case, the balance parts 34 are disposed on the main body part 31 at intervals centering on the central axis of the fitting part 33. Likewise, the balance portions 34 are identical in shape and structure and equal in weight, so that the center axis of the fitting portion 33 of the shaft structure 30 is the center of force balance of the entire shaft structure 30.

Referring to fig. 1, in order to increase the contact area between the balance portion 34 and the upper cover 20, the limiting effect on the shaft structure 30 is improved. Then, the key structure 100 further includes a guiding structure 35, and the guiding structure 35 includes a guiding portion 351 disposed on the balancing portion 34 and a guiding adapting portion 352 disposed on the upper cover 20 and adapted to the guiding portion 351.

Illustratively, the guiding portion 351 is a groove opened on the balancing portion 34, and the extending direction of the groove is the same as the extending and retracting direction of the shaft structure 30 relative to the upper cover 20, and the guiding fitting portion 352 is a protrusion provided on the upper cover 20, and fits with the groove by the protrusion to form a guiding function to the shaft structure 30.

Specifically, as shown in fig. 1, in the present embodiment, the number of the balance parts 34 is two, the two balance parts 34 are symmetrically disposed on the main body part 31 centering on the central axis of the fitting part 33, the guide parts 351 are disposed on the end surfaces of the two balance parts 34 away from the fitting part 33, the guide parts 351 are grooves, and the guide fitting parts 352 are disposed on the hole walls of the through-hole structure 20a of the upper cover 20, the guide fitting parts being protrusions.

Illustratively, the guiding portion 351 is a rib provided on the balance portion 34, and the extending direction of the rib is the same as the extending and retracting direction of the shaft structure 30 relative to the upper cover 20, and the guiding fitting portion 352 is a groove provided on the upper cover 20, and the rib and the groove are adapted to form a guiding function for the shaft structure 30.

Referring to fig. 3 to fig. 5, in an embodiment, the balancing portion 34 includes a first sub-portion 341 disposed on the main body portion 31 and a second sub-portion 342 disposed on the first sub-portion 341 and away from the adapting portion 33, and the second sub-portion 342 is adapted to be connected to the key cap 202. It is understood that, in the present embodiment, the balance portion 34 is composed of two parts, such that the overall length of the balance portion 34 is longer or the side length in the circumferential direction is longer, and in order to increase the position of fitting with the key cap 202 and ensure that the key cap 202 is smoothly pressed down, the second sub-portion 342 away from the fitting portion 33 is fitted with the key cap 202. For example, if the mounting post 204 is provided at a position corresponding to the key top 202, a blind hole or the like is formed in the second sub-portion 342 so as to fit the mounting post 204. In this way, the shaft structure 30 having the balance portion 34 of the present embodiment can be fitted to the key cap 202 having a longer length.

For example, the second sub-portion 342 may be disposed along the extending direction of the first sub-portion 341, i.e., disposed in parallel with an included angle of 180 °. Of course, in other embodiments, the extending direction of the first sub-portion 341 and the extending direction of the second sub-portion 342 form an included angle smaller than 180 °.

Illustratively, the number of the balance parts 34 is two, the two balance parts 34 are symmetrically provided to the main body part 31 centering on the central axis of the fitting part 33, the lengths of the first sub-parts 341 of the two balance parts 34 are the same, and the lengths of the second sub-parts 342 are also the same, and a guide part 351 is provided on the end surface of the second sub-part 342 away from the fitting part 33, the guide part 351 being a groove, and a guide fitting part 352 is provided on the hole wall of the through-hole structure 20a of the upper cover 20, the guide fitting being a protrusion.

Referring to fig. 4, in one embodiment, the second sub-portion 342 defines a groove structure 34a adapted to the key cap 202. It will be appreciated that the slot structure 34a is adapted to the inner wall of the key cap 202 with the mounting post 204, so that the connection between the balance 34 and the key cap 202 further improves the smoothness of the key cap 202 during its movement.

Alternatively, referring to fig. 5, in another embodiment, the second sub-portion 342 has a groove structure 34a, and a sleeve 34b adapted to the key cap 202 is disposed in the groove structure 34a. It can be understood that the sleeve 34b is adapted to the mounting post 204 on the inner wall of the key cap 202, and the sleeve 34b can be replaced according to the size of the key cap 202, i.e. the outer diameter of the sleeve 34b can be kept consistent to fit the groove structure 34a of the second sub-portion 342, and the inner diameter of the sleeve 34b can be adjusted according to the size of the mounting post 204. In this way, the balance 34 can accommodate different types of key caps 202.

The first sub-portion 341 and the second sub-portion 342 of the balancing portion 34 may be connected by an integral molding method or may be detachably connected according to actual use requirements. Wherein, to the two adopt integrated into one piece mode to connect, the structural stability of balancing portion 34 is higher, avoids the easy condition that takes place the pine in junction to take place, and, to the two adoption detachably connected mode, then can adjust the whole length or the width of balancing portion 34 according to the second sub-portion 342 of different length of demand replacement.

Referring to fig. 4, in one embodiment, one end of the second sub-portion 342 is integrally formed at one end of the first sub-portion 341. It is understood that the second sub-portion 342 and the first sub-portion 341 may extend in the same direction, that is, one end of the second sub-portion 342 is integrally formed at one end of the first sub-portion 341 away from the adapting portion 33. Of course, in other embodiments, one end of the second sub-portion 342 may be integrally formed at other ends of the first sub-portion 341, that is, the balance portion 34 with different shape structure is obtained.

Referring to fig. 5, in an embodiment, the second sub-portion 342 and the first sub-portion 341 are separately disposed, and one end of the second sub-portion 342 is detachably connected to one end of the first sub-portion 341. Here, the second sub-portion 342 can be connected to the first sub-portion 341 by a screw, and of course, the second sub-portion 342 can also be connected to the first sub-portion 341 by a plug-in or snap-in connection.

For example, as shown in fig. 5, a clamping hole 361 is formed on the first sub-portion 341, and a clamping arm 362 is provided on the second sub-portion 342, and the clamping arm 362 is clamped into the clamping hole 361 to realize the detachable connection therebetween.

Referring to fig. 6 and 7, the long key assembly 200 provided by the present application includes a bottom plate 201, a key cap 202 and the key structure 100, wherein the base 10 of the key structure 100 is fixed on the bottom plate 201, the key cap 202 is adapted to the adapting portion 33 of the key structure 100, and each of the balancing portions 34 of the key structure 100 extends along the length direction of the key cap 202. It will be appreciated that the bottom plate 201 provides the necessary support and power for the key structure 100. The key cap 202 provides a pressing feedback to the key structure 100.

On the basis of the key structure 100, the long key assembly 200 provided by the present application has a simpler overall structure and is easier to assemble.

Here, as shown in fig. 8, the key cap 202 includes a cap body 203 and a mounting post 204 provided on the cap body 203, and the mounting post 204 is fittingly connected to the fitting portion 33 of the shaft structure 30 of the key structure 100. And the balance part 34 of the shaft structure 30 is in abutting fit with the mounting post 204 of the cap body 203.

Referring to fig. 6 and 7, in one embodiment, the upper cover 20 of the key structure 100 is fixedly connected to the bottom plate 201. It can be understood that the upper cover 20 of the key structure 100 is adapted according to the size of the balance part 34 of the shaft body, and the upper cover 20 is connected with the base 10 in a snap-fit manner.

The embodiment of the present application further provides a key device, which includes the key structure 100.

The application provides a button device, on the basis that has above-mentioned button structure 100, the dismouting of being convenient for, and the cost is lower.

The above description is only exemplary of the present invention and should not be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A key structure, characterized by: the key cap comprises a base, an upper cover and a shaft structure, wherein the upper cover is covered with the base, the shaft structure penetrates through the upper cover and can move telescopically relative to the upper cover, the shaft structure comprises a main body part, an extension part, an adaptation part and a plurality of balance parts, the extension part is arranged on one side of the main body part and is adapted to the base, the adaptation part is arranged on the other side of the main body part and is adapted to the key cap, the balance parts and the adaptation part are arranged on the same side of the main body part, and the balance parts are arranged around the adaptation part; the upper cover is provided with a through hole structure for limiting the balance parts, so that the shaft structure can stably move in a telescopic manner relative to the upper cover.

2. The key structure according to claim 1, wherein: each balance part is symmetrically arranged on the main body part by taking the central axis of the adapting part as a center.

3. The key structure according to claim 1, wherein: the key structure further comprises a guide structure, and the guide structure comprises a guide part arranged on the balance part and a guide adaptive part arranged on the upper cover and matched with the guide part.

4. A key structure according to any one of claims 1 to 3, wherein: the balance part comprises a first sub part arranged on the main body part and a second sub part arranged on the first sub part and deviating from the matching part, and the second sub part is matched and connected with the keycap.

5. The key structure according to claim 4, wherein: the second sub-part is provided with a groove structure matched with the keycap; alternatively, the first and second electrodes may be,

the second sub-portion is provided with a groove structure, and a sleeve matched with the keycap is arranged in the groove structure.

6. The key structure according to claim 4, wherein: one end of the second sub-portion is integrally formed at one end of the first sub-portion.

7. The key structure according to claim 4, wherein: the second sub-part and the first sub-part are arranged in a split mode, and one end of the second sub-part is detachably connected to one end of the first sub-part.

8. The utility model provides a long key assembly, includes bottom plate and key cap, its characterized in that: the key structure of any one of claims 1 to 7, further comprising a base of the key structure fixed to the base plate, the key cap being adapted to the adapter of the key structure, and the balance portions of the key structure extending along a length of the key cap.

9. The long key assembly of claim 8, wherein: the upper cover of the key structure is fixedly connected to the bottom plate.

10. A key device, characterized by: comprising a key structure according to any one of claims 1 to 7.

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