Patent Application
20130305875
1. Field of the Invention
This invention relates to a linkage assembly, more particularly to a scissors-type linkage assembly for a key device.
2. Description of the Related Art
Referring to
The first and second levers 11, 12 are pivotally connected to each other by inserting the pivot shaft 111 into the pivot hole 121. Each of the first and second levers 11, 12 has one end coupled to the keycap 100. An angle defined between the first and second levers 11, 12 determines the position of the keycap 100.
In order to have sufficient supporting strength for the keycap 100 and to ensure that the pivot shaft 111 can stably rotate in the pivot hole 121, the diameter of the cross section of the pivot shaft 111 is preferably greater than 0.7 mm. Thus, the thicknesses of the first and second levers 11, 12 are required to be greater than 0.8 mm, which is adverse to the miniaturization of a key device.
Therefore, an object of the present invention is to provide a scissors-type linkage assembly for a key device that can overcome the aforesaid drawback associated with the prior art.
Accordingly, a scissors-type linkage assembly for a key device of this invention comprises:
a first lever having a lever body and a pivot shaft that protrudes laterally from the lever body, the pivot shaft having at least one arcuate portion with a curvature centered at an axis of the pivot shaft, and at least one non-arcuate portion connected to the arcuate portion, the arcuate and non-arcuate portions being rotatable about the axis of the pivot shaft; and
The arcuate portion contacts slidably and rotatably a hole-defining wall of the rounded hole portion, the non-rounded hole portion is wider than the non-arcuate portion, and the non-arcuate portion is movable toward or away from a hole-defining wall of the non-rounded hole portion and is capable of limiting an angle of rotation of the pivot shaft when contacting the hole-defining wall of the non-rounded hole portion.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which:
Before the present invention is described in greater detail with reference to the accompanying preferred embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.
Referring to
The first lever 3 has a lever body 32 and a pivot shaft 31 that protrudes laterally from the lever body 32. The pivot shaft 31 has an arcuate portion 311 and a non-arcuate portion 312 connected to the arcuate portion 311. In this embodiment, the arcuate portion 311 is formed with a curvature centered at an axis of the pivot shaft 31, and the non-arcuate portion 312 extends substantially radially from the arcuate portion 311. The arcuate and non-arcuate portions 311, 312 are rotatable about the axis of the pivot shaft 31. In this embodiment, a cross section of the arcuate portion 311 has a diameter of 0.4 mm.
The second lever 4 is formed with a pivot hole 41 that receives the pivot shaft 31, and that has a rounded hole portion 411 and a non-rounded hole portion 412. The rounded hole portion 411 is centered at the axis of the pivot shaft 31.
The arcuate portion 311 contacts slidably and rotatably a hole-defining wall 413 of the rounded hole portion 411. The non-rounded hole portion 412 is wider than the non-arcuate portion 312. The non-arcuate portion 312 is movable toward or away from a hole-defining wall 414 of the non-rounded hole portion 412 and is capable of limiting an angle of rotation of the pivot shaft 31 when contacting the hole defining wall 414 of the non-rounded hole portion 412. Accordingly, the displacement of the keycap 200 can be limited, and the thickness of the key device may be reduced.
As best shown in
This embodiment is similar to the first embodiment, except that, in this embodiment, the pivot shaft 31 has two of the non-arcuate portions 312, and the arcuate portion 311 is substantially circular in cross section. The non-arcuate portions 312 are opposite to each other substantially in a diametrical direction.
In addition, the pivot hole 41 has the rounded hole portion 411 and two of the non-rounded hole portions 412. The hole-defining wall 413 of the rounded hole portion 411 contacts slidably and rotatably the arcuate portion 311. The hole-defining walls 414 of the two non-rounded hole portions 412 are formed oppositely in the diametrical direction. Each of the hole-defining walls 419 is a surrounding wall to surround a respective one of the non-arcuate portions 312, and is flared from the hole-defining wall 413 of the rounded hole portion 411. Each of the non-arcuate portions 312 is movable between two opposite sides of the hole-defining wall 414 of a respective one of the non-rounded hole portions 412. When the arcuate portion 311 slidably and rotatably moves along the hole-defining wall 413 of the rounded hole portion 411, each of the non-arcuate portions 312 moves from one side of the hole-defining wall 414 of the respective one of the non-rounded hole portions 412 to the other side. Accordingly, the range of angular rotation of the pivot shaft 31 is limited by the hole-defining walls 414 of the non rounded hole portions 412.
In this embodiment, the pivot shaft 31 has two of the non-arcuate portions 312. The arcuate portion 311 has a cross sectional shape conforming to a major segment of a circle, and has two ends 3111, 3112 that are opposite to each other in a chordal direction of the cross section of the arcuate portion 311. The non-arcuate portions 312 extend oppositely and respectively from the two ends 3111, 3112 of the arcuate portion 311.
The hole-defining wall 414 of the non-rounded hole portion 412 of the pivot hole 41 has first, second, third and fourth wall segments 4141, 4142, 4143, 4144. The first wall segment 4141 is connected to the hole-defining wall 413 of the rounded hole portion 411. The second wall segment 4142 is spaced apart from the first wall segment 4141. The third and fourth wall segments 4143, 4144 are opposite to each other, each of which interconnects the first and second wall segments 4141, 4142. When the arcuate portion 311 slidably and rotatably moves along the hole-defining wall 413 of the rounded hole portion 411, one of the non-arcuate portions 312 moves away from the first wall segment 4141 to the second wall segment 4142, and the other of the non-arcuate portions 312 moves away from the second wall segment 4142 to the first wall segment 4141. Accordingly, the range of angular rotation of the pivot shaft 31 is limited by the hole-defining wall 414 of the non-rounded hole portion 412.
It should be noted that although the non-arcuate portions 312 are formed symmetrically in
The pivot shaft 31 has a cross sectional shape conforming to a major segment of a circle, an arcuate surface of the major segment forms the arcuate portion 311, and a chordal surface of the major segment forms the non-arcuate portion 312. The arcuate portion 311 has two ends 3111, 3112 that are opposite to each other in a chordal direction of the major segment. The non-arcuate portion 312 has two ends 3121, 3122 connected respectively to the two ends 3111, 3112 of the arcuate portion 311.
The pivot hole 41 has a cross sectional shape conforming to a major segment of a circle. The space of the major segment of the pivot hole 41 is larger than the volume of the pivot shaft 31. An arcuate surface of the major segment of the pivot hole 41 forms the hole-defining wall 413 of the rounded hole portion 411, and a chordal surface of the major segment of the pivot hole 41 forms the hole-defining wall 414 of the non-rounded hole portion 412.
When the arcuate portion 311 slidably and rotatably moves along the hole-defining wall 413 of the rounded hole portion 411, one of the two ends 3111, 3112 moves toward the hole-defining wall 414 of the non-rounded hole portion 412, and the other one of the two ends 3111, 3112 moves away from the hole-defining wall 414 of the non-rounded hole portion 412. Accordingly, the range of angular rotation of the pivot shaft 31 is limited by the hole-defining wall 414 of the non-rounded hole portion 412.
The pivot shaft 31 of this embodiment is similar to that of the fourth embodiment, except that, in this embodiment, the major segment of the pivot shaft 31 is beveled at a corner between the arcuate surface and the chordal surface. Accordingly, in this embodiment, the chordal surface and the beveled surface of the major segment form two non-arcuate portions 312 of the pivot shaft 31. With the beveled pivot shaft 31, the thickness of the first and second levers 3, 4 can be further reduced. In this embodiment, the pivot shaft 31 has an arc radius of 0.35 mm.
The shape of the pivot hole 41 of this embodiment is the same as that of the fourth embodiment.
When the arcuate portion 311 slidably and rotatably moves along the hole-defining wall 413 of the rounded hole portion 411, one of the two ends 3111, 3112 moves toward the hole-defining wall 414 of the non-rounded hole portion 412, and the other one of the two ends 3111, 3112 moves away from the hole-defining wall 414 of the non-rounded hole portion 412. Accordingly, the range of angular rotation of the pivot shaft 31 is limited by the hole-defining wall 414 of the non-rounded hole portion 412.
To sum up, with the specific designs of the pivot shaft 31 and the pivot hole 41, the range of angular rotation of the pivot shaft 31 can be limited, thereby limiting the displacement of the keycap 200. Moreover, in this invention, the first and second levers 3, 4 have reduced thicknesses, and the pivot shaft 31 is less likely to break and can rotate smoothly in the pivot hole 41. Thus, the first and second levers 3, 4 can be firmly connected with each other so as to support the keycap 200.
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.
