Keypad with long key travel and improved touch feeling
AssigneeThales
InventorJean-Louis Bigand
Life of this patent
Estimating the term…
Abstract
A keypad includes at least one push-button switch and a key to operate the switch along a translational axis. The geometric dispersions of the keypad are accounted for, to the lengthening of the travel of the key and to the enhancement of the tactile sensation when the key is pressed to operate the switch. The keypad includes a plunger, interposed between the key and the switch, of which a stiffness along the translational axis increases continuously with an increase in the compression of the plunger. A slight stiffness at the beginning of compression allows a long travel of the key, while a greater stiffness at the end of compression gives a good tactile sensation with an assured contact even when there are off-center pressures on the key.
Claims14
A keypad comprising:
- a push-button switch;
- a key making it possible to operate the push-button switch along a translational axis;
- and
- a plunger interposed between the key and the switch, a stiffness of the plunger along the translational axis increasing with a travel of the key before the switch is actuated, the plunger comprising a recess, a portion of the plunger comprising the recess defining an upper portion of the plunger which has a first stiffness, and a remaining portion of the plunger defining a lower portion of the plunger which has a second stiffness, the second stiffness being greater than the first stiffness, at the beginning of the travel of the key, the plunger being essentially deformed at the upper portion of the plunger, and beyond a point of travel for which the key comes into contact with a bottom of the recess, the plunger being essentially deformed at the lower portion of the plunger, the stiffness of the plunger therefore increasing in line with the first and then the second stiffness.
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Dependencies are inferred from the claim text.