SUMMARY OF THE INVENTION
This invention provides a momentary electrical push switch that can be configured for 2 or more activation positions. The switch has a top surface, or “key” top, which is pressed down upon in different areas to actuate the switch's different activation positions. The key top can be of various shapes, such as quadrangles, circle, hexagon, etc., or irregular shapes, to suit a particular application.
The key top can be graphically and/or topographically divided into multiple segments, or activation zones, each corresponding to a different activation position of the switch. The segments can be of varying sizes and shapes on a given key.
The key allows free-form movement when pressing down upon it, without requiring the user to use specific or narrowly-defined motions to actuate the various activation positions. This is useful and/or necessary where fluidity of motion is required, such as in typing, where users can be operating the keys with great rapidity and with individualized typing styles in which the manner in which they push the keys, and the particular area of the key they strike, can vary widely from user to user.
FIELD OF THE INVENTION
The present invention relates to input devices, particularly to a momentary-action push switch for operation in electronic devices, a push switch with a key-like top actuator button, and a switch with multiple activation positions which outputs different signals in response to pressing forces applied to different areas of the button's top surface.
BACKGROUND OF THE INVENTION
Momentary electrical push switches, particularly with essentially flat tops and with varying shapes, are widely used in electronic devices, for inputting information as well as control commands into the device.
Such switches are typically configured with limited symmetrical activation positions that require the user to use specific or narrowly-defined motions to actuate the various activation positions.
This invention addresses the need for a multi-position push switch which can have activation positions at various non-uniform and/or non-symmetrical areas on the button top, and which allows free-form movement when pressing down upon it, which is advantageous where fluidity of motion is required, such as in typing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows shows key (10) in a side perspective view, with contact ring (11) extending downward from the bottom face of the key.
FIG. 1a shows a view of key (10) from the bottom, with circular contact ring (11).
FIG. 1b shows a cross-sectional view of key (10) and the contact ring top surface (12).
FIG. 1c shows a bottom-upside perspective of key (10) with compressible silicone center element (13) located in the center of contact ring (11).
FIG. 2 shows a magnified section of key (10) with contact ring top surface (12) making contact with surface (20) below the key when the key is pressed down from the top.
FIG. 2a shows center element (13) deforming slightly as key (10) is being pressed down at a slight angle to the horizontal causing center element (13) to be pressed down upon surface (20).
FIG. 3a shows the top face of key (30) with 6 activation positions, where the key top is divided into 6 segments (30a-30f).
FIG. 3b shows contact ring (34), indicated by a dotted outline, as it would be seen if looking through the top of key (30).
FIGS. 3c and 3e show the electrical contact arrangements of top layer (31) and bottom layer (33), respectively, of a flexible membrane switch positioned under key (30).
FIG. 3d shows electrically non-conductive spacer layer (32) with window cutouts (32a-32f), which is positioned between top and bottom layers (31) and (33) when the switch is assembled.
FIG. 3f shows an alternate top layer (35) with contact pattern (35a) that could be used with bottom layer (33) in the membrane switch.
FIG. 3g, shows a top view of the multi-layer assembly of the membrane switch with top layer (35), spacer layer (32) beneath the top layer, and bottom layer (33) beneath the spacer layer.
FIG. 4a shows the concentric positioning of the windows of the spacer layer (32) shown in FIG. 4f in relation to key (30) and its contact ring (34), shown in dotted lines.
FIG. 4b shows the concentric positioning of the windows of the spacer layer in relation to the key and the contacts of top layer (31), shown in FIG. 4e.
FIG. 4c shows cross-section (A-A) of an assembly consisting of, top to bottom: key (30) (FIG. 4d), top switch layer (31) (FIG. 4e), spacer layer (32) (FIG. 4f), and bottom switch layer (33) (FIG. 4g), and their respective cross-sections (A-A). The downward arrows (B) represent a downward force being applied to the top of the key at segment 5 (30e) shown in FIG. 4d.
FIGS. 5a-5c show the result of a finger pressing down on key (30) at activation positions (30a), (30b) and (30c), respectively, causing the key to make contact with the surface beneath it at locations (A), (B) and (C), respectively.
FIGS. 6a-6c show the result of a finger pressing down on key (30) at activation positions (30a), (30b) and (30c), respectively, causing the key to make contact with contacts (31a), (31b) and (31c), respectively, of top layer (31) of the membrane switch shown in FIG. 4e.
FIGS. 7a-7c show a finger pressing down on key (30) at activation position (30b), at 3 different points within that key segment, with the finger pressing at the locations shown in FIGS. 7a-7c causing contact ring (34) to press down on switch top layer (31) at contact sections (70), (71) and (72), respectively.
FIG. 8a shows a wide radial aperture width (82) of window (80a) in switch spacer layer (80) and a narrow radial aperture width (83) of window (81a) in switch spacer layer (81).
FIG. 8b shows top switch layer (84) for a 4-position key with contacts (84a-84d), top switch layer (86) for a 5-position key with contacts (86a-86e), and top switch layer (88) for a 6-position key with contacts (88a-88f) of varying arc lengths.
FIG. 9a shows key (90) with 5 activation positions (90a-90e).
FIG. 9b shows contact ring (91), shaded and indicated by a dotted outline, as it would be seen if looking through the top of key (90).
FIG. 9c shows the top layer (92) of a membrane switch with 20 contacts arranged in a circle, with the contacts electrically grouped into 4 groups.
FIG. 9d shows the bottom layer (94) of a membrane switch with 20 contacts arranged in a circle, with the contacts electrically grouped into 5 groups
FIG. 9e shows switch spacer layer (96), with a window (97) between the top and bottom layers that is a continuous open circle.
FIG. 9f shows the contact ring (91) concentrically aligned with respect to the spacer opening (97) in the key assembly.
FIG. 10a shows top switch layer (92) with its circle of 20 contacts (93) labeled a-t, which are connected to circuit traces labeled 1-4.
FIG. 10b shows bottom switch layer (94) with its circle of 20 contacts (95) labeled a′-t′, which are connected to circuit traces labeled A-E.
FIG. 10c shows a magnified view of contacts c-f, wherein a key contact ring is making contact with top switch layer (92) below it with a contact section arc (100) that spans contacts c, d and e.
FIG. 10d shows a magnified view of contacts c-f, wherein a key contact ring is making contact with top switch layer (92) below it with a contact section arc (100) that spans only contacts d and e.
FIG. 10e is a truth table, Table 1, showing the key segment of key (90) shown in FIG. 9a actuated for given simultaneous connecting of combinations of contacts t-h of switch layer (92) with corresponding contacts t′-h′ of switch layer (94) positioned underneath it.
FIG. 11 shows an angled parallelogram key shape (110) with six activation positions (110a-110f).
FIG. 11a shows key (110) with circular contact ring (111), indicated by a dotted outline, as it would be seen if looking through the top of the key.
FIG. 11b shows key (110) from a bottom view, with contact ring (111).
FIG. 11c shows the positions of electrical contacts (114) of a top switch layer and windows (115) of a spacer when arranged beneath key 110.
FIG. 11d shows key (112) with oval contact ring (113), indicated by a dotted outline, as it would be seen if looking through the top of the key.
FIG. 11e shows key (112) from a bottom view, with contact ring (113).
FIG. 11f shows the positions of electrical contacts (116) of a top switch layer and windows (117) of a spacer when arranged beneath key 112.
FIG. 12a shows key (120) with a circular contact ring (121) having straight facets positioned at various locations around the contact ring.
FIG. 12b shows a magnified section (122) of contact ring (121) with a straight facet of width (123).
FIG. 12c shows key (124) with a contact ring (125) that is not a continuous circle, but rather has cutouts (126) located at various positions around the ring.
FIG. 13 shows 2 identical keys (10) and (131) surrounded by faceplate (130) and suspended across 2 support beams (133) by means of flexible material (132) attached to the underside of the keys.
FIG. 13a shows a cross-section of FIG. 13 at A-A, with flexible material (132) attached to the underside of the key outside the area of the contact ring (11).
FIG. 13b shows a cross-section of key (134) in which the key is surrounded by flexible material (135) and has an internal core (136) consisting of a rigid material.
FIG. 14 shows 2 identical keys (141a) and (141b) surrounded by a faceplate (140) and suspended across 2 support beams (143) by a flexible material (142).
FIG. 14a shows key top (141a) viewed from the bottom and contact ring section (144).
FIG. 14b shows in exploded B-B cross-section that key (141a) has a separate contact ring section (144).
FIG. 14c shows cross-section A-A of FIG. 14, with the raised central circular surface (144b) shown in FIG. 14b attached to the bottom surface of the key top (141a), which captures the flexible support material (142) in-between the two.
FIG. 15a shows a flexible suspension (150) for key (151) shown in FIG. 15b.
FIG. 15c shows A-A cross-section of key (151).
FIGS. 15d and 15e show a top and bottom view, respectively, of key (151) attached to suspension (150).
FIG. 16 shows 2 identical keys (151) and (161) surrounded by a faceplate (160) and suspended across 2 support beams (162) by suspension (150), and shows locations of contact ring (151a) and compressible snap action dome (151c) as they would be seen if looking through the top of key (151).
FIG. 16a shows key (151) A-A cross section of FIG. 16.
FIG. 17a shows suspension (150) from FIG. 15a.
FIG. 17b shows key (171) viewed from the bottom and contact ring section (172).
FIG. 17c shows in exploded A-A cross-section that key (171) has a separate contact ring section (172).
FIG. 17d shows a bottom view of key (171) attached to suspension (150).
FIG. 17e shows B-B cross-section of key (171) with contact ring section (172) attached to suspension (150).
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a preferred embodiment of the key (10) in a side perspective view. A contact ring (11) extends downward from the bottom face of the key. The contact ring top surface (12) is the part of the key that makes contact with an electrical, optical, or electro-mechanical detection mechanism immediately below it to cause actuation of an electrical signal corresponding to which area of the key's top surface has been pressed by the user. In the preferred embodiment shown in FIG. 1, and the corresponding cross-section view of FIG. 1b, the contact ring top surface (12) has a rounded profile. FIG. 1a shows a view of key (10) from the bottom, with the circular contact ring (11) centered on the key. FIG. 1b shows the cross-section of key (10) across the line A-A. Surface (12), as well as part or all of the contact ring, can be constructed from either a rigid, or non-rigid flexible deformable, material.
FIG. 1c shows a bottom-up side perspective of key (10) with a center element (13) located in the center of the contact ring (11) and extending above the top of the contact ring. The center element shown is a soft-silicone compressible dome typically found in the construction of computer keyboards. A variety of shapes and materials, preferably with flexible and compressible properties, can be used for a center element, with one of the advantages being to provide a tactile feel and response during key depression. A silicone dome such as that shown in FIG. 1c can provide a dual-state “oil can” snap action that is felt when pressing keys on a typical computer keyboard. A center element can also facilitate the key tilting down at an angle when pressed anywhere non-central on its top surface, rather than the entire key moving down in a horizontal disposition. A center element is not required for the operation of the key, however.
FIG. 2 shows a magnified section of key (10) of FIG. 1, illustrating the contact ring top surface (12) making contact with a surface (20) below the key when the key is pressed down from the top in a manner causing the key to move downward at a slight angle to the horizontal, referenced by imaginary line (22) extending normal to surface (20) and up through the key. The result of the key contacting surface (20) with an angular attitude is that only a partial circumferential section (21) of the contact ring top surface makes contact with surface (20). Surface (20) would typically contain an electro-mechanical component, such as the flexible membrane switch shown in FIG. 4c, which discerns where a given contact section (21) is located along the circumference of the contact ring, resulting in the producing of an electrical signal indicating which of the key's activation positions section (21) corresponds to.
FIG. 2a shows center element (13) deforming slightly as key (10) is being pressed down at a slight angle to the horizontal and the center element is pressed down upon surface (20).
In FIGS. 1 and 2, the contact ring (11) is shown as a ring encircling an empty interior area; however, alternatively the interior area of the ring can be partially or completely filled in (solid), since the contact ring meets surface (20) below at an angle when the key is pressed down (FIG. 2 and FIGS. 5a-5c), and the interior area of the contact ring does not affect the operation of the invention in any way.
FIG. 3a shows the top face of a key (30) with 6 activation positions, which can be a key such as (10), where the key top is divided, graphically and/or topographically, into 6 segments (30a-30f) with corresponding indicia marked 1 thru 6, respectively, on the face of the key. The area delineated by each segment defines the activation zone of each activation position of the key, such that if the key is pressed down anywhere within a given activation zone, it will cause actuation of its associated activation position. FIG. 3b shows contact ring (34), indicated by a dotted outline, as it would be seen if looking through the top of the key.
For an embodiment wherein the detection mechanism underneath the key is a flexible membrane switch, typically constructed of thin sheets of polyester with electrically-conductive contacts, FIG. 3c shows the top layer (31) of a flexible membrane switch with its electrical contacts facing down, as if looking through from the top. Top layer (31) has 6 contacts (31a-31f) electrically connected together. FIG. 3e shows the bottom layer (33) of the switch with its 6 contacts (33a-33f) facing up. None of the contacts are electrically connected to each other.
FIG. 3d shows an example of a separation layer (32) which is made of an electrically non-conductive material and serves as both a mechanical spacer and electrical insulator and is positioned between top and bottom layers (31) and (33) when the switch is assembled. The separation layer (32) has cutouts, or windows, (32a-32f), which correspond to the locations of contacts (31a-31f) and (33a-33f) and allow the top contacts to come into electrical contact with their corresponding bottom contacts when pressed down by the contact ring (34). In the example spacer shown in FIG. 3d, the windows (32a-32f) are separated by spans of spacer material (32g) between adjacent windows. The spans (32g) between the windows serve as separators between the activation positions, and the spans can be made narrower or wider to decrease or increase the operational separation between activation positions.
In the example shown in FIGS. 3c and 3e, the pattern of the contacts of the top and bottom layers, not including the connections to them, are identical: if placed one layer on top of the other, each top layer contact would be identical in size, shape and location to the bottom layer contact beneath it. FIG. 3f shows an example of an alternate top layer (35) that could be used with bottom layer (33) but its contact pattern (35a) does not have a 1:1 correspondence in shape or size to the contact pattern of (33). It is only required, as shown in the example of FIG. 3g, that the areas of the top contact pattern (35a) and bottom contact pattern (33a-33f) correspond within the window areas (32a-32f) of the separation layer where the contact ring will be pressing down to make an electrical connection between the layers.
FIG. 4c shows a cross-section (A-A) of an assembly, consisting of, top to bottom: key (30), top switch layer (31), spacer layer (32), and bottom switch layer (33). FIGS. 4d-4g show the cross-section location (A-A) of those switch elements, respectively. FIG. 4a shows the concentric positioning of the windows of the spacer layer in relation to the key and its contact ring (34), and FIG. 4b shows the concentric positioning of the windows of the spacer layer in relation to the key and the top layer's contacts.
The downward arrows (B) in FIG. 4c represent a downward force being applied to the top of the key at segment 5 (30e); this would cause the contact ring (34) to press downward on contact (31e) of the top switch layer so that the top layer deforms downward through window (32e) of the spacer layer so that contact (31e) touches, and makes electrical contact with, bottom layer contact (33e). This would create an electrical connection actuating activation position 5 (30e) of the key.
In this embodiment of the switch design, each key activation position has its own spacer layer window through which the corresponding top and bottom switch layer contacts come together to make an electrical connection and actuate that activation position.
FIG. 5a shows the result of a finger pressing down on key (30) at activation position (30a). This causes the key to make contact with the surface beneath it at location (A), as explained in FIG. 2. If the key assembly is that shown in FIG. 4c, then this would cause contact ring (34) to press down on contact (31a) of top switch layer (31) as shown in FIG. 6a. FIG. 5b shows the result of a finger pressing down on the key at activation position (30b), which causes the key to make contact with the surface beneath it at location (B), resulting in contact ring (34) pressing down on contact (31b) as shown in FIG. 6b. FIG. 5c shows the result of a finger pressing down on the key at activation position (30c), which causes the key to make contact with the surface beneath it at location (C), resulting in contact ring (34) pressing down on contact (31c) as shown in FIG. 6c.
FIGS. 7a-7c show a finger pressing down on key (30) at activation position (30b), but at 3 different points within that key segment. For the finger pressing at the location shown in FIG. 7a, the contact ring (34) will press down on switch top layer (31) at contact section (70). For the finger pressing at the location shown in FIG. 7b, the contact ring (34) will press down on switch top layer (31) at contact section (71). For the finger pressing at the location shown in FIG. 7c, the contact ring (34) will press down on switch top layer (31) at contact section (72). Thus, the key can be pressed at various locations within a given key segment and will actuate that activation position as long as the contact section falls within the confines of the switch spacer layer window for that activation position.
FIG. 8a shows how the radial width of the aperture of the windows in a switch spacer layer can be varied to tune the downward force, or actuation force, required to press down on the key to actuate an activation position. The examples show window (80a) having a wide aperture of width (82), and window (81a) having a narrow aperture of width (83). As the radial width of the window increases, less force is needed to cause the top switch layer to deform in order to press down upon the bottom switch layer. The thickness of the spacer layer will also affect required key actuation force: the thicker the spacer layer, the larger the distance separating the top and bottom switch layers, and thus the farther the top layer must deform to touch the bottom layer.
The number, locations, and sizes of activation positions on a key can be tailored to a specific application or requirement by varying the configuration of contacts on the top and bottom switch layers along with the corresponding windows in the switch spacer layer. FIG. 8b shows examples of this: top switch layer (84) for a 4-position key with contacts (84a-84d) and the corresponding spacer window (85) for each contact; top switch layer (86) for a 5-position key with contacts (86a-86e) and the corresponding spacer window (87) for each contact; and top switch layer (88) for a 6-position key with contacts (88a-88f) and the corresponding spacer window (89) for each contact. As shown by the example of top switch layer (88), the activation zones of a key do not necessarily have to be the same size or in a symmetrical or regularly-spaced configuration.
In an alternate switch configuration, as shown and explained in FIGS. 9a-10d and Table 1, there is not a dedicated partitioned spacer window for each of the key's activation positions, such as shown in the example of FIG. 3d. There is also not a single top layer contact, with a single corresponding bottom layer contact, defining each activation position, such as shown in the examples of FIG. 3c and FIG. 3e.
FIG. 9a shows the top face of key (90), which can be a key such as (10), where the key top is divided, graphically and/or topographically, into 5 segments, or activation positions, (90a-90e) with corresponding indicia marked 1 thru 5, respectively, on the face of the key. FIG. 9b shows contact ring (91), shaded and indicated by a dotted outline, as it would be seen if looking through the top of the key.
FIG. 9c shows the top layer (92) of a membrane switch that would be located below the key with its electrical contacts facing down, as if looking through from the top; it has 20 contacts arranged in a circle, and the contacts are electrically grouped into 4 groups. FIG. 9d shows the bottom layer (94) of the membrane switch located below the key; it has 20 contacts arranged in a circle, and the contacts are electrically grouped into 5 groups. In this example, the pattern of the contacts of the top and bottom layers, not including how they are connected, are identical: if placed one layer on top of the other, each top layer contact would be identical in size, shape and location to the bottom layer contact beneath it.
FIG. 9e shows the switch spacer layer (96): the window (97) between the top and bottom layers is a continuous open circle, without any of the inter-window separations such as (32g) as shown in FIG. 3d. Such separations could be included but are not in the present example. Thus the center element (96a) of the spacer layer in this example is a separate piece of material centered within, but not connected to, the outer circle cutout of the spacer layer.
FIG. 9f shows how the contact ring (91) would be concentrically aligned with respect to the spacer opening (97) in the key assembly. The key assembly would be in the same fashion as shown in FIG. 4c: each of the 20 contacts of the switch top layer would be directly above its corresponding bottom layer contact, and the key contact ring, switch top layer contacts, spacer layer, and bottom layer contacts would be vertically concentrically aligned, top to bottom, respectively.
FIGS. 10a and 10b show switch layers (92) and (94), with their circles of 20 contacts (93) and (95) labeled a-t and a′-t′ respectively for purposes of illustration. The 4 groups of contacts in FIG. 10a are connected to circuit traces labeled 1-4, and the 5 groups of contacts in FIG. 10b are connected to circuit traces labeled A-E.
FIGS. 10c and 10d show a magnified view of contacts c-f (93). In an example configuration, FIG. 10c is a representation of the contact ring (91) making contact with switch layer (92) below it (as explained in FIG. 2) with a contact section arc (100) that spans twice the center-to-center pitch of the contacts (93). This contact section span (100) would, at any given location along the circle of contacts, press down on either 2 contacts simultaneously, such as d and e (FIG. 10d), or 3 contacts simultaneously, such as c, d, and e (FIG. 10c). As a result, in this configuration there would be 40 (2×20 contacts) distinct contact combinations: 20 with 2 contacts pressed simultaneously, and 20 with 3 contacts pressed simultaneously.
Table 1 is a truth table showing the key segment 1-5 (90a-90e) actuated for given simultaneous connecting of combinations of contacts t-h (93) of switch layer (92) with corresponding contacts t′-h′ (95) of switch layer (94) positioned underneath it. Row 7 of the table shows the instance illustrated in FIG. 10c, where contacts c, d, and e are simultaneously pressed down and connect with corresponding contacts c′, d′, and e′ underneath, respectively: the connecting of contact c with c′ connects circuit traces 2 and C together, the connecting of contact d with d′ connects circuit traces 2 and D together, and the connecting contact e with e′ connects circuit traces 2 and E together. This is encoded by Table 1 as an actuation of key segment 2, indicated in the rightmost column.
The example contact configuration shown in FIGS. 9c, 9d, 10a, and 10b shows all contacts (93) and (95) as the same size, spaced uniformly around the circle; however, both the size of each individual contact, as well as individual inter-contact spacings, can be varied to suit different applications.
If a key construction incorporating flexible deformable materials resulted in a contact arc that varied in length depending on the amount of force being applied downward upon the key (e.g., a light pressure would span a contact pitch of 1, a greater pressure a pitch of 2, up to a pitch of 4 at maximum pressure), then a corresponding truth table could be constructed to provide for that. As an example: if only contact c (FIG. 10a) was pressed down, that would actuate key segment 2; if contacts t, a, b, and c were pressed down simultaneously, that would actuate key segment 1; if contacts a, b, c, and d were pressed down simultaneously, that would be in-between key segments 1 and 2, so no key segment would be actuated.
In this embodiment of the invention as illustrated by the examples in FIGS. 9a-10d, wherein the designated area on the key top for each key segment is determined by software (i.e., the configuration of the key's truth table such as Table 1), an additional feature is that a key's segments can be changed on the fly purely in software, allowing a key to have its key segment areas, as well as its number of key segments, dynamically changeable. By distinguishing applied pressure to the key through how many contacts, e.g., (93), are pressed down simultaneously, this design can also enable a pressure-sensitive functionality, such as providing a second key segment within a key segment: fewer contacts pressed within a key segment (light pressure) would actuate a primary signal for that key segment, and more contacts pressed within that key segment (exerting further pressure) would actuate a secondary signal for that same key segment.
The keys of this invention in the previous figures have been illustrated as squares, but a key of this invention can be implemented in a variety of shapes such as a circle, hexagon, etc., or even irregular shapes. As an example, FIG. 11 shows an angled parallelogram key shape (110) with six activation positions (110a-110f). Such a key can be used, for example, as a 6-position key for the keyboard invention taught in U.S. Pat. No. 7,131,780. FIG. 11a shows key (110) with contact ring (111), indicated by a dotted outline, as it would be seen if looking through the top of the key. FIG. 11b shows key (110) from a bottom view, with contact ring (111). The contact ring does not necessarily have to be a circle; FIGS. 11d-11f show key (112) with an oval contact ring (113). As with a circular contact ring such as (111), where the electrical contacts (114) and corresponding spacer windows (115) shown in FIG. 11e correspond to the shape and size of the circular contact ring, the electrical contacts (116) under key (112) and their corresponding spacer windows (117) shown in FIG. 11f would correspond to the shape and size of the oval contact ring (113).
FIG. 12a shows key (120) with a circular contact ring (121) having straight facets positioned at various locations around the contact ring. FIG. 12b shows a magnified section (122) of key (120) with a straight facet of width (123).
FIG. 12c shows key (124) with a circular contact ring (125) that is not a continuous circle, but rather has cutouts (126) located at various positions around the circle.
FIG. 13 shows an embodiment of a suspension for key (10). Two identical keys (10) and (131) are shown surrounded by a faceplate (130). The keys are suspended across 2 support beams (133) by means of a flexible material (132) which is attached to the underside of the key. FIG. 13a shows a cross-section of FIG. 13 at A-A, and shows the flexible material attached to the underside of the key outside the area of the contact ring (11).
FIG. 13b shows a cross-section of a configuration similar to that of FIG. 13a, but instead of a separate flexible material attached to the key, the key (134) is also constructed from the same flexible material, with an internal core (136) made of a more rigid material, so that the key and flexible suspension (135) extending to the support beams (133) are a single piece.
FIG. 14 shows an embodiment similar to that shown in FIG. 13, with 2 identical keys (141a) and (141b) surrounded by a faceplate (140) and suspended across 2 support beams (143) by a flexible material (142). The keys are of a 2-piece construction. FIG. 14a shows key top (141a) viewed from the bottom and contact ring section (144), which are 2 separate pieces attached together. This is shown in the exploded B-B cross-section of FIG. 14b: key (141a) has a separate contact ring section (144) with a raised central circular surface (144b). FIG. 14c is cross-section A-A of FIG. 14, and shows the raised central circular surface (144b) shown in FIG. 14b attached to the bottom surface of the key top (141a), which captures the flexible support material (142) in-between the two. The gap (145) shown in FIG. 14b is just enough to allow the flexible support material) to fit securely between the top section and the contact ring section.
The 2-piece construction of this key allows the contact ring (144a) to extend to the outer edges of the key without encountering the problem of not having enough surface area on the key bottom on which to attach the suspension.
FIG. 15a shows a suspension (150) for key (151) shown in FIG. 15b with contact ring (151a). For this suspension to work optimally, it should be made out of a thin, flexible material such as spring steel. The suspension has a central section (150a) to which the key directly attaches, as shown in FIGS. 15d and 15e. This central section is connected to a side element (150c) on either side via a connecting element (150b). The side elements then connect to a top and bottom support element (150d) which would be anchored to a supporting structure such as shown in FIG. 16 to properly suspend the key.
FIG. 15b shows the underside of key (151), which has a small cylindrical peg (151b) protruding near each corner, which is also shown in the A-A cross-section of key (151) in FIG. 15c. These pegs pass through their corresponding holes (150g) in the suspension to attach the key to the suspension, as shown in the bottom-side view of FIG. 15e. If the key is constructed of a material such as ABS or other plastic, these pegs can be heat-staked to form a strong and permanent attachment of the key to the suspension.
The objective of the design of this suspension is to allow the key to move freely and unconstrained—and with equal resistance—in any direction when pressed downward at activation areas on its top surface. This allows optimal functionality of the key. The serpentine bends (150e) of the side elements (150c) each act as an independent suspension at each of the corners of the key. In addition, the narrow connecting elements (150b) allow the key limited rotation about axis (152) shown in FIG. 15d.
The key motion can be tuned to a lighter or heavier force by varying a number of elements of the suspension, including the distance of the serpentine bends (150e), the width of the connecting elements (150b) and side elements (150c), the thickness and type of the suspension material, etc.
FIG. 16 shows an embodiment similar to that shown in FIG. 13, with 2 identical keys (151) and (161) surrounded by a faceplate (160) and suspended across 2 support beams (162) by suspension (150), which is attached to the support beams by means of fasteners (163). The keys each contain a compressible snap action dome (151c) beneath the bottom surface of the keys, such as (13) shown in FIGS. 1c and 2a and discussed in the Detailed Description of the Drawings. The locations of contact ring (151a) and snap action dome (151c) as they would be seen if looking through the top of key (151) are indicated by dashed outlines. FIG. 16a shows key (151) A-A cross section of FIG. 16 including A-A cross-section of snap action dome (151c).
FIG. 17d shows, from a bottom view, how a 2-piece key design similar to that shown in FIGS. 14a and 14b would attach to suspension (150) from FIG. 15a. The key consists of a top key section (171) and a contact ring section (172) that attaches to the bottom of the top section, as shown in FIGS. 17b, 17d and 17e. FIG. 17e is the B-B cross-section of FIG. 17d: it shows the contact ring section is attached to the top key section at the raised circular surface (171b) shown in FIG. 17c, which is an exploded A-A cross-section of FIG. 17b. The gap (172) is just enough to allow the suspension (150) to fit securely between the top section and the contact ring section, as shown in cross-section FIG. 17e.
As shown in FIGS. 17b and 17d, the 2-piece construction of this key allows the contact ring (172a) to extend to the outer edges of the key while allowing the suspension's central section (150a) to remain a single piece with sufficient area for adequate strength and mechanical integrity.
Patent Grant
11232919
