Low cost keyboard with key tops defining surface of curved profile
AssigneeHoneywell Inc.
InventorKevin F. Clancy
Life of this patent
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Abstract
A keyboard having a plurality of rows of depressable keys whose key tops define a surface of concave profile curved about an axis. The concave profile is achieved with key tops and key stems of identical configuration by maintaining a key holder plate which carries the key stems in a concave profile. The concave profile of the key holder plate is produced by forming the plate with graduated flexibility across its width and mounting it on a substantially rigid base so that a region of the plate located midway between its edges is drawn to a position outside the plane containing the edges of the plate by means of a plurality of fasteners between the base and a plate located along its length.
Claims12
A keyboard having a two dimensional array of keys, each key having a key top and each movable along an axis, said keys arranged in a plurality of rows where said plurality of rows has two outer rows and whose key tops are located in surface of curved profile, comprising:
- a key holder plate having mutually orthogonal width, length and thickness, the width generally extending between first and second parallel lines and the length extending between first and second ends, said key holder plate being relatively rigid along its length and having graduated flexibility across its width, its flexibility decreasing with distance from the first or second lines to a location intermediate the first and second lines said key holder plate having an array of key guide apertures extending through its thickness along axes of key movement transverse to said width and length;
- a plurality of keys mounted in the key guide apertures;
- a substantially rigid base underlying said key holder plate;
- and
- snap retaining means between said base and said key holder plate, said snap retaining means located inboard of the outer rows of keys, and between the first and second ends of said base for restraining the portion of said key holder plate along said location to a position outside the plane defined by the first and second lines to configure the array of key tops and a surface of curved profile.
A keyboard comprising:
- a base with a concave upper surface thereon, the upper surface being curved about an axis;
- a membrane switch assembly overlaying the concave surface on said base, said switch assembly forming a plurality of rows of switches, the rows being generally parallel with said axis, the switches being individually actuatable by exerting force on the switch assembly at the switch location;
- an array of resilient frustoconical boots overlaying said switch assembly and arranged in a plurality of rows so that a boot is substantially aligned with each switch location, each boot having a large open end adjacent said switch assembly and a small closed end of which the inner surface contacts the switch assembly when the boot is depressed;
- a key holder plate having an array of key guide apertures therethrough and arranged in a plurality of rows so that a key guide aperture is substantially aligned with each switch location, said key holder plate being substantially rigid along the rows of key guide apertures and having graduated flexibility transverse to the rows of key guide apertures, with the area of maximum stiffness located between the outer rows;
- a plurality of keys mounted in the key guide apertures for movement toward and away from said base, the outer surfaces of the small ends of said boots abutting said keys so as to bias them away from said base;
- and
- snap retaining means for securing said key holder plate to said base in a concave profile about said axis, said snap retaining means including a plurality of fasteners spaced along the area of maximum stiffness of said key holder plate for restraining said key holder toward said base.
A method of producing a keyboard having a two dimensional array of keys whose key tops define a surface of concave profile curved about an axis, the method comprising the steps of :
- providing an actuator assembly including a plurality of depressable keys mounted in a plate in an array of key guide apertures arranged in a plurality of parallel rows, the key holder plate being substantially rigid along the rows of key guide apertures and having graduated flexibility transverse to the rows of key guide apertures, with the area of maximum stiffness located substantially midway between the outer rows;
- providing a switch assembly including a substantially rigid base having a concave upper surface thereon curved about an axis, a membrane assembly overlaying the concave surface on the base and having an array of electrical switching elements therein arranged in a pattern corresponding to the pattern of key guide apertures in the actuator assembly, and an array of key return elements overlaying the membrane assembly in a pattern corresponding to the pattern of key guide apertures in the actuator assembly, the switching elements being individually actuatable by exerting a force on the membrane assembly at the switching element locations;
- and
- attaching the actuator assembly to the concave upper surface of base of the switch assembly in a manner that the rows of key guide apertures are parallel with the axis of curvature of the concave surface, the edges of the key holder are held spaced from the concave surface, and the area of maximum stiffness of the key holder is drawn toward the curved surface by means of a plurality of fasteners spaced along the length of the area of maximum stiffness, whereby the key holder is restrained in a concave profile.
Dependencies are inferred from the claim text.