Mechanical numeric keypad

Abstract

This application discloses a mechanical keypad. According to one embodiment, a mechanical keypad may include: a keycap including a post extending from its bottom surface; a structural element including a channel configured to receive the post passing through it; and a key retaining device that securely receives the post in a recess or opening formed therein via the channel, and includes a key switch interface on its lower surface. When the key post is securely received in the key retaining device, the keycap and the key retaining device can move substantially in tandem.

Description

Technical Field

[0001] This disclosure generally relates to mechanical keypads. Background Technology

[0002] Mechanical keypads are commonly found in point-of-sale devices, ATMs, and other similar equipment, sometimes serving as the sole point of interaction for users. These keypads can also become targets for tampering. For example, an attacker might attempt to access the keypad's secure area by removing one of its keys. Such access could lead to the leakage of secure information. Summary of the Invention

[0003] This application discloses a mechanical keypad. According to one embodiment, a mechanical keypad may include: a keycap including a post extending from its bottom surface; a structural element including a channel configured to receive the post passing through it; and a key retaining device that securely receives the post in a recess or opening formed therein via the channel, and includes a key switch interface on its lower surface. When the key post is securely received in the key retaining device, the keycap and the key retaining device can move substantially in tandem.

[0004] In one embodiment, the mechanical keypad may include a spring between the structural element and the keycap, such that when the keycap is pressed, the spring compresses, causing the key retainer to travel a shorter distance than the keycap travels.

[0005] In one embodiment, the key retaining device may be configured to be damaged when the key post is removed from the recess or opening.

[0006] In one embodiment, the post can be mechanically fixed in a key fixing device.

[0007] In one embodiment, the mechanical keypad may include multiple columns.

[0008] In one embodiment, the mechanical keypad may include a web between the keycaps and the structural elements, which prevents debris and foreign objects from entering the structural elements.

[0009] In one embodiment, the mechanical keypad may include key switches for interacting with a key switch interface, wherein pressing a keycap causes the key switch interface to actuate the key switches.

[0010] In one embodiment, the key retaining device is mechanically unstable relative to the key switch when the post is not received in the recess or opening therein.

[0011] In one embodiment, the lower surface of the key fixing device may have a convex portion.

[0012] In one embodiment, the key switch interface may protrude from the lower surface of the key fixing device.

[0013] According to another embodiment, a mechanical keypad may include: a keycap having a plurality of posts extending from its bottom surface; a structural element including a plurality of channels formed therethrough; a key retaining device that securely receives the plurality of posts in a post receiving structure formed therein on the opposite side of the structural element from the keycap, the key retaining device including a key switch interface on its lower surface; and a key switch layer including key switches that interact with the key switch interface and are registered with keys. The key retaining device may be mechanically unstable relative to the key switches when not properly engaged with the plurality of posts, and when the key posts are securely received in the key retaining device, the keycap and the key retaining device can move substantially in unison, and pressing the keycap causes the key switch interface securely receiving the key posts for the keycap to actuate the key switches.

[0014] In one embodiment, the key retaining device can be configured to be damaged when the key post is removed.

[0015] In one embodiment, the column receiving structure may include a recess.

[0016] In one embodiment, the column receiving structure may include an opening.

[0017] In one embodiment, the key switch may be centrally located between multiple posts.

[0018] In one embodiment, the mechanical keypad may be positioned within a housing and may include an alarm switch having an associated safety element located between the housing and the alarm switch, such that the alarm switch is activated when the housing and the alarm switch are separated.

[0019] In one embodiment, the bottom surface of the key fixing device may have a convex portion.

[0020] In one embodiment, the key switch interface may protrude from the key fixing device.

[0021] In one embodiment, a structural element may include a recess formed on its lower surface, wherein the recess is provided for a key fixing device.

[0022] In one embodiment, the mechanical keypad may include a spring between the structural element and the keycap, such that when the keycap is pressed, the spring is compressed before the key retaining device moves. Attached Figure Description

[0023] To gain a more complete understanding of the invention, its objectives, and advantages, reference is now made to the following description in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 A mechanical keypad according to one embodiment is depicted;

[0025] Figure 2 A cross-sectional view of a mechanical keypad according to one embodiment is depicted;

[0026] Figure 3 A cross-sectional view of the key fixing device along its length according to one embodiment is depicted; and

[0027] Figure 4A and Figure 4B An embodiment is depicted in which the keycap is pressed on its side edge. Detailed Implementation

[0028] The embodiments relate to a mechanical keypad. Some embodiments may use key-holding devices (such as key safety clips) to secure one or more posts of the keycaps via structural components (such as light guides). The keycaps do not directly actuate the key switches (e.g., key metal dome switches); instead, the key switches are actuated by the key-holding devices.

[0029] In some embodiments, the key retaining device may include a raised feature that interacts with the key switch, such as a key switch interface. If the key retaining device is not in place, is not properly aligned, is damaged, etc., the keycap may improperly actuate the key switch.

[0030] Some embodiments may provide additional security features. For example, in some embodiments, the key retaining device can be used to prevent unintended keycap removal, such as by vandalism, security attacks, etc. In one embodiment, if a keycap is removed, it is difficult or impossible to reattach the key retaining device to the keycap post without gaining secure access to the device's internal interior. Such access to the secure interior may activate security devices (e.g., alarm switches, case-open switches, etc.), thereby detecting an attack.

[0031] refer to Figures 1-3 According to some embodiments, a mechanical keypad is disclosed. Figure 1 An exploded view of a mechanical keypad according to one embodiment is depicted. Figure 2 Draw a cross-sectional view of a mechanical keyboard. Figure 3 A cross-sectional view of the key fixing device 130 along its length is depicted.

[0032] Embodiments of the mechanical keypad 100 may include a top shell 110, keycaps 115, a body 120, structural elements 125, key fixing devices 130, safety elements 135 (e.g., a shell opening switch or a portion thereof), a key switch layer 140, and a frame 145.

[0033] In one embodiment, the top shell 110 may be part of an enclosure in which a keypad is provided. Examples of enclosures include ATM enclosures, point-of-sale equipment enclosures, keypad lock enclosures, or any other suitable enclosure in which security of the key switches and / or electronics provided beneath the keypad is desired.

[0034] In one embodiment, keycap 115 may be provided as a set of keycaps, or as individual keycaps, etc.

[0035] In one embodiment, each keycap 115 may have one or more posts 117 provided on its underside. The posts 117 may be provided on the underside of the keycap 115 in any suitable manner and at any suitable location. For example, if a post 117 is provided, it may be provided at the center of the keycap 115, or it may be off-center. If multiple posts 117 are used, they may be arranged symmetrically, asymmetrically, etc. For example, if two posts 117 are provided, these two posts 117 may be arranged equidistant from the center of the keycap 115 and along a straight line bisecting the keycap 115. Other arrangements of multiple posts 117 may also be used.

[0036] In one embodiment, post 117 may be formed as part of keycap 115.

[0037] The web 120 may be provided and shaped to prevent debris and foreign matter (e.g., dust, water, etc.) from entering the structural element 125. In one embodiment, the web 120 may be made of a flexible material (e.g., silicone resin, silicone rubber, etc.).

[0038] In one embodiment, each keycap 115 may be bonded to the web 120 using, for example, an adhesive.

[0039] In one embodiment, the web 120 can provide a bias to return the keycap 115 to the upward position. The web 120 can also hold the keycap 115 in its intended position. If it becomes opaque or is obscured by the opaque layer, the web 120 can further prevent or reduce light leakage.

[0040] Structural element 125 can provide a structural basis for keycap 115. In one embodiment, post 117 from keycap 115 can pass through channels, holes, openings, or apertures 127 in structural element 125 and can move from structural element 125 with minimal (if present) resistance. For example, post 117 can slide within channels, holes, openings, or apertures 127 formed in structural element 125.

[0041] In one embodiment, structural element 125 may be a light guide, which can be used to provide backlighting for keycap 115. Structural element 125 may provide any additional functionality as needed and / or desired.

[0042] Key retaining device 130 may be provided on the opposite side of structural element 125 and may include one or more post receiving structures 134, such as openings or recesses, each for receiving a post 117. Each keycap 115 may be provided with a corresponding key retaining device 130.

[0043] In one embodiment, when the keycap 115 is not actuated or pressed, the top portion of the key retaining device 130 may contact the lower surface of the structural element.

[0044] The key retainer 130 can securely engage the post 117 such that the keycap 115 and the corresponding key retainer 130 move in unison when engaged. For example, the post 117 can be pressably engaged with an opening or recess 134 formed in the key retainer 130. For example, during assembly, the post 117 can be pushed into the opening or recess 134 of the key retainer 130 and can be held connected by mechanical force (e.g., friction) or by a unidirectional flexible bushing or flange that engages with the recessed portion of the post 117, so that the keycap 115 and the key retainer 130 move in unison or substantially in unison when engaged. In another embodiment, the post 117 can be secured to the key retainer 130 using adhesives, heat staking, welding, fastening clips, pin clips, etc. Other connection methods may be used as needed and / or desired.

[0045] In another embodiment, the key retainer 130 may engage the post 117 so that the keycap 115 and the corresponding key retainer 130 can move in unison, but by different distances. For example, a spring (not shown) may be provided between the post 117 and the key retainer 130. In this arrangement, although the keycap 115 and the key retainer 130 move substantially in unison, the keycap 115 may travel a greater distance than the key retainer 130 because the spring will compress, resulting in the key retainer 130 moving a shorter distance than the keycap 115.

[0046] In one embodiment, if any keycap 115 is unnecessarily removed, one or more posts 117 are removed from the key retainer 130, which may damage the key retainer 130 to the extent that the posts 117 cannot be securely reinserted to allow proper operation of the keypad. For example, the key retainer 130 may include a break point (not shown) such that when sufficient force is applied to pry off the keycap 115, the key retainer 130 may be damaged, broken, etc., preventing the posts 117 from properly re-engaging with the key retainer 130. In another embodiment, the retaining mechanism in the recess or opening 134 may be damaged, preventing the keycap 115 and the key retainer 130 from properly re-engaging. For example, if the posts 117 are to be reinserted into the recess or opening 134, the posts 117 and the opening 134 may not engage with each other, or the keycap 115 and the key retainer 130 may not move in unison.

[0047] The key-holding device 130 may have a tab or other structure (not shown) that engages with the post 117 when the post 117 is assembled and secured to the key-holding device 130. When forcefully separated, the tab or other structure may break off or otherwise be damaged, preventing the post 117 from being re-securely engaged when attempting to re-engage it to the key-holding device 130. In another embodiment, the post 117 may include a securing mechanism (not shown) that secures it to the key-holding structure 130, which may be damaged if the keycap is forcefully removed. For example, the post 117 may have a flexible tab (not shown) that allows it to be inserted and secured to the key-holding structure 130, or a pin or open-end clamp (not shown) that may be attached to the post during assembly to hold it in place relative to the key-holding structure. When forcefully removed, the tab, pin, open-end clamp, or similar mechanism will be damaged or cause the post 117, the key-holding structure 130, or both to be destroyed, preventing them from being properly and securely re-engaged.

[0048] In one embodiment, the key fixing device 130 may be a disposable device.

[0049] The key retaining device 130 may further include a key switch interface 132 on its lower surface. The key switch interface 132 may correspond to and interface with the key switch 144.

[0050] One or more alarm switches (not shown) may be provided on or with the key switch layer 140, frame 145, printed circuit board, etc. (not shown). For example, the alarm switches may be in the form of a case-open switch. For example, each alarm switch may interact with a safety element 135, which may be positioned between the top housing 110 and the alarm switch. In another embodiment, the safety element may be positioned between the structural element 125 and the alarm switch. Thus, when the top housing 110 and / or structural element 125 is removed, lifted, or separated from the key switch layer 140, frame 145, and / or printed circuit board, or its position is otherwise changed, the alarm switch can recognize such change and can trigger an alarm.

[0051] For example, in one embodiment, safety element 135 may be a safety plunger that, in its unchanged state, has a downward force applied to it to cause the plunger to engage similarly with an alarm switch. If the frame of the device is to be opened or tampered with, this downward force may be altered, reduced, or eliminated, which may cause the safety plunger to disengage from the alarm switch and trigger an alarm.

[0052] In one embodiment, the safety element 135 may extend through the key switch layer 140 into the frame 145 to interact with a printed circuit board (not shown) that may be inside or beneath the frame 145. In one embodiment, the safety element 135 may be an integral part of the top shell 110, structural element 125, or web 120.

[0053] In one embodiment, a recess (not shown) may be provided in structural element 125 for receiving the end of safety element 135. In another embodiment, a through hole may be provided in structural element 125 to allow safety element 135 to pass through structural element 125.

[0054] The key switch layer 140 may include one or more key switches 144. Each key switch 144 may be associated with a keycap 115. The key switch 144 may be formed as a dome on the key switch layer 140.

[0055] The key switch 144 may be offset from the post 117 and the channel, hole, opening, or aperture 127, such that if the keycap 115 is removed, the key switch 144 is not directly accessible via the channel, hole, opening, or aperture 127. For example, the key switch 144 may be positioned between the recess or opening 134 in the key retainer 130.

[0056] In one embodiment, the key switch layer 140 may be metal.

[0057] In one embodiment, the key switch layer 140 may be part of a printed circuit board.

[0058] In one embodiment, each key switch 144 may be formed as multiple layers. For example, the first layer may include a convex dome, while the second layer may include a switching circuit. The first layer may be adhered to the switching circuit, located on top of it, etc., such that when the first layer is pressed, contacted, etc., the switching circuit is actuated.

[0059] Other designs and mechanisms (e.g., mechanical switches, carbon switches, etc.) for key switch 144 may be used as needed and / or as desired.

[0060] In another embodiment, the key switch 144 may protrude from the plane of the key switch layer. For example, the key switch 144 may include a metal dome that, when pressed, causes key registration.

[0061] In one embodiment, the key retainer 130 may have a lower surface shape that is mechanically unstable relative to the key switch layer 140 and / or the key switch 144. For example, the key retainer 130 may have a convex lower surface, and the key switch layer 140 may include the key switch 144 having a dome-shaped structure made of metal or other suitable material, such that when the key retainer 130 is properly engaged, the lower surface of the key retainer 130 (e.g., the key switch interface 132) compresses the dome to align with the key. However, if the keycap 115 disengages from the key retainer 130, the key retainer 130 will not align with the key switch 144 because the lower surface of the key retainer 130 does not flatly abut against the dome of the key switch layer 140 and / or the key switch 144. Therefore, when the keycap 115 is pressed, the key switch 144 will not align with the key.

[0062] In one embodiment, mechanical instability caused by the lower surface of the key retainer 130 and / or the shape of the key switch 144 prevents the key retainer 130 from easily remaining in a properly aligned state with the key switch assembly. Therefore, when the keycap 115 has been removed or detached from the key retainer 130, it is difficult to reinsert the post 117 of the keycap 115 into the key retainer 130.

[0063] In another embodiment, the lower surface of the key retainer 130 may include a ridge or any other suitable shape that increases the mechanical instability of the safety device and the key switch layer 140, making it difficult to align the keycap 115 with the key retainer 130, so that pressing the keycap 115 will actuate the key switch 144.

[0064] In one embodiment, structural element 125 may be configured to include one or more recesses 146 on its lower surface. In one embodiment, a single recess 146 may be provided in which all key switches 144 are located. Therefore, in this embodiment, there is no mechanism for accommodating the removable key retaining device 130 near its associated key switch 144.

[0065] In another embodiment, a plurality of key switches 144 may be positioned within each recess 146. For example, recesses may be provided vertically or horizontally for all key switches 144 in a row or column. Thus, in this embodiment, the disassembled key retainer 130 will remain in the recess of its column or row, but it will still be difficult to align and reattach the key retainer 130 to the corresponding post 117.

[0066] In another embodiment, a recess 146 may be provided for each key switch 144. Thus, in this embodiment, a detachable key retainer 130 may remain in the recess of its key switch. The recess 146 may be formed larger than the key retainer 130 to allow any key retainer 130 removed, detached, or removed from the corresponding post 117 of the keycap 130, thereby allowing the benefit of aligning and reattaching the key retainer 130 to the corresponding post 117 of the keycap 115.

[0067] In one embodiment, the recess 146 may be formed by ribs 128 formed in the structural element 125. The number and orientation of the ribs 128 may vary as needed and / or desired.

[0068] The frame 145 can provide a base for the keypad and can accommodate external components such as processors and memory.

[0069] refer to Figure 3 The diagram provides a cross-sectional view of the key retaining device 130 along its length. The key retaining device 130 may include a key switch interface 132 on its lower surface. The key switch interface 132 may be convex, thereby enhancing mechanical instability with the key switch layer 140. In one embodiment, when the post 117 is secured in the key retaining device 130, the key switch interface 132 may be aligned with one of the key switches 144.

[0070] refer to Figure 4A and Figure 4B The keycap 115 may have a shape such that it can be pressed on the side end of the keycap 115 between the post 117 and the edge of the keycap 115. For example, in one embodiment, the keycap 115 may interface with the key retainer 130 such that when the keycap 115 is pressed on its side end, the interaction between the post 117 and the structural element 125 forces the keycap 115 and the key retainer 130 to move in a downward direction, thereby providing an acceptable feel to the user. The key retainer 130 creates a pivot point on the side opposite to the pressed end, which results in a lever action that facilitates engagement of the key switch 144, even if the keycap 115 is pressed off-center.

[0071] Those skilled in the art will understand that the present invention is not limited to the content specifically shown and described above. Rather, the scope of the invention includes combinations and sub-combinations of the features described above, as well as variations and modifications not present in the prior art. It should also be recognized that these embodiments are not mutually exclusive.

[0072] Those skilled in the art will readily understand that the embodiments disclosed herein are readily available and applicable. Many embodiments and adaptations of the invention, as well as many variations, modifications, and equivalent arrangements beyond the foregoing description, will be apparent or reasonably proposed from the invention and its foregoing description without departing from the spirit or scope of the invention.

[0073] Therefore, although the invention has been described in detail herein with respect to exemplary embodiments thereof, it should be understood that this disclosure is merely an illustrative and exemplary description of the invention and is intended to provide a feasible disclosure of the invention. Consequently, the foregoing disclosure is not intended to be construed as limiting the invention or to otherwise exclude any other such embodiments, adaptations, variations, modifications, or equivalent arrangements.

Claims

1. A mechanical keypad, comprising: A keycap, which includes a pillar extending from its bottom surface; A structural element comprising a channel configured to receive the column passing through it; as well as A key fixing device that securely engages the post in a recess or opening formed therein through the channel, and includes a key switch interface on its lower surface. When the post is securely engaged in the key fixing device, the keycap and the key fixing device move substantially in unison; and When the post is removed from the recess or opening, the key fixing device is damaged and cannot be re-engaged with the post.

2. The mechanical keypad according to claim 1, further comprising a spring between the structural element and the keycap, such that when the keycap is pressed, the spring is compressed, causing the key retaining device to travel a shorter distance than the keycap travels.

3. The mechanical keypad according to claim 1, wherein the post is mechanically fixed in the key fixing device.

4. The mechanical keypad according to claim 1, further comprising a plurality of posts.

5. The mechanical keypad according to claim 1, further comprising: The web between the keycap and the structural element prevents debris and foreign objects from entering the structural element.

6. The mechanical keypad according to claim 1, further comprising: Key switches for interacting with the key switch interface; Pressing the keycap causes the key switch interface to activate the key switch.

7. The mechanical keypad of claim 1, wherein the key retaining device is mechanically unstable relative to the key switch when the post is not received in the recess or opening therein.

8. The mechanical keypad according to claim 1, wherein the lower surface of the key fixing device includes a convex portion.

9. The mechanical keypad according to claim 1, wherein the key switch interface protrudes from the lower surface of the key fixing device.

10. A mechanical keypad, comprising: Keycaps, which have multiple pillars extending from their bottom surface; Structural element, which includes multiple channels formed therethrough; A key fixing device that securely engages the plurality of posts in a post receiving structure formed therein on the side of the structural element opposite to the keycap, the key fixing device including a key switch interface on its lower surface. as well as A key switch layer, comprising key switches that interact with the key switch interface and are registered with a key; The key fixing device is mechanically unstable relative to the key switch when it does not properly engage with the plurality of posts; When the post is securely engaged in the key fixing device, the keycap and the key fixing device move substantially in unison; Pressing the keycap causes the key switch interface, which is securely received by the post for the keycap, to actuate the key switch. When the post is removed, the key fixing device is damaged and cannot be re-engaged with the post.

11. The mechanical keypad of claim 10, wherein the post receiving structure includes a recess.

12. The mechanical keypad of claim 10, wherein the post receiving structure includes an opening.

13. The mechanical keypad of claim 10, wherein the key switch is centrally located between the plurality of posts.

14. The mechanical keypad of claim 10, wherein the mechanical keypad is positioned within a housing, and further includes an alarm switch comprising an associated safety element located between the housing and the alarm switch such that the alarm switch is activated when the housing and the alarm switch are separated.

15. The mechanical keypad according to claim 10, wherein the bottom surface of the key fixing device includes a convex portion.

16. The mechanical keypad according to claim 10, wherein the key switch interface protrudes from the key fixing device.

17. The mechanical keypad of claim 10, wherein the structural element includes a recess formed on its lower surface, wherein the recess is provided for the key retaining device.

18. The mechanical keypad of claim 10, further comprising a spring between the structural element and the keycap, such that when the keycap is pressed, the spring is compressed before the key retaining device moves.

19. A mechanical keypad, comprising: A keycap, which includes a pillar extending from its bottom surface; A structural element comprising a channel configured to receive a portion of the keycap and through which the post passes; as well as A key fixing device that securely engages the post in a recess or opening formed therein through the channel, and includes a key switch interface on its lower surface. When the post is securely engaged in the key fixing device, the keycap and the key fixing device move substantially in unison; When the keycap is pressed, the key retaining device separates from the structural element; and When the post is removed from the recess or opening, the key retaining device is damaged and cannot be re-engaged with the post.

20. The mechanical keypad of claim 19, further comprising a spring between the structural element and the keycap, such that when the keycap is pressed, the spring compresses, causing the key-holding device to travel a shorter distance than the keycap travels.

21. The mechanical keypad of claim 19, wherein the key retaining device is configured to be damaged when the post is removed from the recess or opening.

22. The mechanical keypad of claim 19, wherein the posts are mechanically secured in the key fixing device.

23. The mechanical keypad according to claim 19, further comprising a plurality of posts.

24. The mechanical keypad according to claim 19, further comprising: The web between the keycap and the structural element provides a bias that causes the keycap to reach an upward position, and the web prevents debris and foreign objects from entering the structural element.

25. The mechanical keypad according to claim 19, further comprising: Key switches for interacting with the key switch interface; Pressing the keycap causes the key switch interface to activate the key switch.

26. The mechanical keypad of claim 19, wherein the key retaining device is mechanically unstable relative to the key switch when the post is not received in the recess or opening therein.

27. The mechanical keypad according to claim 19, wherein the lower surface of the key fixing device includes a convex portion.

28. The mechanical keypad according to claim 19, wherein the key switch interface protrudes from the lower surface of the key fixing device.

29. A mechanical keypad, comprising: Keycaps, which have multiple pillars extending from their bottom surface; A structural element comprising a plurality of channels formed therethrough, wherein the plurality of channels are configured to receive a portion of the keycap and the plurality of posts; A key fixing device securely receives the plurality of posts in a post receiving structure formed therein on the side of the structural element opposite to the keycap, the key fixing device including a key switch interface on its lower surface. as well as A key switch layer comprising key switches that interact with the key switch interface and are registered with a key, wherein the key switches and the key switch interface are laterally offset from the plurality of posts of the keycap; When the post is securely received in the key fixing device, the keycap and the key fixing device move substantially in tandem; and When the keycap is pressed, the key switch interface, which securely receives the post for the keycap, is configured to actuate the key switch.

30. The mechanical keypad of claim 29, wherein the key retaining device is configured to be damaged when the post is removed.

31. The mechanical keypad according to claim 29, wherein the post receiving structure includes a recess.

32. The mechanical keypad of claim 29, wherein the post receiving structure includes an opening.

33. The mechanical keypad of claim 29, wherein the key switch is centrally located between the plurality of posts.

34. The mechanical keypad of claim 29, wherein the mechanical keypad is positioned within a housing, and further includes an alarm switch comprising an associated safety element located between the housing and the alarm switch such that the alarm switch is activated when the housing and the alarm switch are separated, wherein in an unchanged state, the safety element engages with the alarm switch due to a downward force, and wherein the downward force on the safety element is configured to change when the housing and the alarm switch are separated to activate the alarm switch.

35. The mechanical keypad according to claim 29, wherein the bottom surface of the key fixing device includes a convex portion.

36. The mechanical keypad of claim 29, wherein the key switch interface protrudes from the key fixing device.

37. The mechanical keypad of claim 29, wherein the structural element includes a recess formed on its lower surface, wherein the recess is provided for the key retaining device.

38. The mechanical keypad of claim 29, further comprising a spring between the structural element and the keycap, such that when the keycap is pressed, the spring is compressed before the key retaining device moves.

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