Key device for keyboard

A key device for a keyboard, comprising:

• a circuit board unit;
• a position unit disposed on said circuit board unit, and including a surrounding frame that defines an inner hole, and that has a bottom surface and a top surface opposite to said bottom surface, a pair of first connection subunits that are connected to said surrounding frame, and a pair of second connection subunits that are connected to said surrounding frame,
• wherein an imaginary plane is formed in said inner hole and is coplanar with said top surface,
• wherein each of said pair of first connection subunits has at least one connection plate that is connected to said surrounding frame, and a connection portion that is connected to and extends from said at least one connection plate to be higher than said top surface in a height direction of said key device, and that has a guide surface facing the imaginary plane, the height direction being a direction from said bottom surface towards said top surface, and
• wherein each of said pair of second connection subunits has at least one connection plate that is connected to said surrounding frame, and a connection portion that is connected to and extends from said at least one connection plate to be higher than said top surface in the height direction, and that has a guide surface facing the imaginary plane;
• a scissor linkage mounted to said position unit in the height direction from said bottom surface towards said top surface, and including a first frame member and a second frame member that are pivotally connected to each other and that cooperatively define a through hole, said first frame member having two lower rods that are respectively and pivotally connected to said connection portions of said pair of first connection subunits, and two upper rods, said second frame member having two lower rods that are respectively and pivotally connected to said connection portions of said pair of second connection subunits, and two upper rods,
• wherein for said first frame member, each of said lower rods abuts against said guide surface of the respective one of said connection portions of said pair of first connection subunits, and
• wherein for said second frame member, each of said lower rods abuts against said guide surface of the respective one of said connection portions of said pair of second connection subunits;
• a resilient member disposed on said circuit board unit and extending through said through hole;
• and
• a keycap having a pair of first pivot portions that are respectively and pivotally connected to said upper rods of said first frame member, and a pair of second pivot portions that are respectively and pivotally connected to said upper rods of said second frame member.