Abstract:
Electric switches are described in which a resilient, electrically conductive, elastomeric member is spaced adjacent but apart from contact means; among features are the elastomeric connector: of sheet form; on metal contacts as a movable contact bridge; defining a simple and durable multiple switch array including a keyboard, a digital coding assembly and a detector; and as the means, especially with proper selection of distributed conductive particles in the elastomer for limited conductivity, of eliminating the electrical effects of bounce in solid state electronic logic circuitry and the like. Fabrication of the switch as a simple, thin compact laminate using printed circuit boards is shown using the preferred silicone elastomer and carbon filler. In preferred embodiments pressure against conductive elastomer sheet means will cause it to connect to a contact element conductively and release of pressure will cause the sheet means to disconnect. The sheet means can be used as a floating connection for one or more circuit elements, and in this form has particular application in a keyboard assembly, particularly in connection with replaceable printed circuit boards and in digital coding techniques with a single printed circuit board. Preferably, the sheet means resiliently, reversibly deforms from first to second conditions, typically engaging the contacts in the deformed or bulged condition. Preferably in one condition the sheet means takes a planar form, positioned by a spacer layer from the contacts. And preferably the contacts are elements of a printed circuit.
Abstract:
A tactile or snap-action membrane keyboard comprises tactile or snap- action protrusions 18 in a membrane sheet 12, each protrusion being asymmetrical with respect to a line or plane of reference. Such a protrusion is stated to be less sensitive to variation in location of actuating force than prior symmetrical protrusions.
Abstract:
TACTILE MEMBRANE KEYBOARD WITH ASYMMETRICAL TACTILE KEY ELEMENTS A tactile or snap action membrane keyboard is presented wherein the tactile or snap action key elements are protrusions in a membrane sheet, the protrusions being asymmetrical to preprogram the collapse of the tactile element.
Abstract:
In a key arrangement, especially in a key field, which has a snap actuating function, a more reliable snap action is achieved, on curvatures moulded in a diaphragm and effecting the snap actuating function when depressed, if these curvatures are asymmetrical with reference to an axis or an axial cutting plane.