Abstract:
A switch for electrically connecting a first terminal with a plurality of other terminals. A contact movable into and out of electrical engagement with a plurality of base contacts is employed. The movable contact may comprise physically parallel wires affixed to a flexible plate, as well as wires which radiate radially outwardly from a point. The physically parallel wires may be inclined to the base contacts or the base contacts may be of different thicknesses to achieve sequential contacting of the base contacts by the movable contact. The base contacts may be any convenient shape, or in the form of concentric spirals or interspersed parallel segments or adjacent triangular-shaped segments.
Abstract:
A low force, low throw, touch operated switch comprising at least one flexible-contact element having a flexible portion and an electrical contact-making portion that is to be deflected into contact with at least one base element. The flexible portion has an effective dimension L and an equivalent spring constant in an axial direction. The contact-making portion is separated by a distance d from an associated base element which is chosen to be less than about 0.008 inch to provide low throw in the switch and to ensure substantially simultaneous and broad area electrical contacting and arc distribution between contact-making portion and base element. The length L is also selected so that the ratio d/L is less than about 0.02, so as to enhance the transverse deflection. The switch is rendered a low force device by selection of the equivalent axial spring constant so that with the d to L relationship just-mentioned the transverse force necessary to touch actuate the switch to produce electrical contact between the contact-making portion and the associated base contact is less than about 100 grams. Parallel contact operation for suitable current division is achieved through the use of a plurality of parallel and extended contact segments that constitute the contact-making portion of the element. Series gaps are utilized to aid in arc suppression and making and breaking of the electrical circuit by including the flexible-contact element as an intermediate element making contact with a plurality of base elements. A corrugated flexible-contact element structure is included to provide good spring action and to achieve a wiping effect to break welds that may be formed during contact closure. The flexible-contact element structure may be provided by a bowed plate with wires affixed thereto.