US 4,978,824 AGranted

Electrical switches

AssigneeRedcliffe Electronics Limited

InventorJohn W. Allen

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Abstract

In an electrical switch having two stable contact states, e.g., a snap-acting butterfly type switch which includes a spring biased movable actuator mounted in a housing and pivotally engaged by contact carrying arms which are urged together by a tension spring, a fulcrum cooperates with each contact arm during normal operation. During movement of the actuator in a first direction, the contact arms pivot about the fulcrums and the contacts begin to move away from a first stable state. When the horizontal position of the arms is reached, the arms pivot rapidly under influence of the tension spring and the contacts "snap" to the second stable state. During the spring biased return movement of the actuator, the contact arms pivot without contact movement until the horizontal position is passed and snap-action occurs. The switch is characterized by an increased gap between the fixed contact when in the open state and/or by a reduction in the amount of actuator movement required for causing the contacts to move from the open to the closed state.

Claims20

Dependent claims

A snap action electrical switch comprising:

a housing;
a displaceable actuator at least in part disposed within said housing;
first electrical contact means mounted within said housing for defining a portion of a path for the flow of electrical current through said housing said first contact means including a stationary electrical contact;
at least a second electrical contact means disposed within said housing for cooperation with said first contact means in defining said current flow path, said second contact means including a movable electrical contact, said stationary and movable contacts having at least a first relative orientation in which said contacts having at least a first relative orientation in which said contacts are spaced apart and a second relative orientation in which said movable contact is in contact with said stationary contact;
means establishing a path for the flow of electrical current between said first electrical contact means and the exterior of said housing;
at least a first movable member coupled to said actuator and to said second electrical contact means movable contact, said first movable member imparting movement to said movable electrical contact in response to displacement of said actuator;
means for resiliently biasing said first movable member whereby said first movable member has at least a first orientation, a second orientation and an unstable equilibrium orientation intermediate said first and second orientations, said first orientation of said first movable member corresponding to said first relative orientation of said contacts and said second orientation of said first movable member corresponding to said second relative orientation of said contacts, said first movable member being arranged to move between said first and second orientations in response to displacement of said actuator, at least one of said first and second orientations of said first movable member being a stable orientation;
means cooperating with said first movable member for causing said movable electrical contact to move towards said stationary electrical contact in a contact-closing direction as said first movable member moves from said first orientation towards said unstable orientation, said contacts remaining closed as said first movable member moves from said second orientation towards said unstable orientation;
and
means for establishing a path for the flow of electrical current between said second electrical contact means and the exterior of said housing.

7 more elements

An electrical switch comprising:

a housing;
a displaceable actuator disposed within said housing;
at least a first pair of electrical contacts disposed within said housing;
means establishing paths for the flow of electrical current between said electrical contacts and the exterior of said housing;
at least a first movable member coupled to said actuator and to one of said electrical contacts, said first movable member imparting movement to said one of said contacts;
means for resiliently biasing said first movable member whereby said first movable member will have a first orientation in which said contacts are closed, a second orientation in which said contacts are open and unstable equilibrium orientation intermediate said first and second orientations, said first movable member moving between said first and second orientations in response to displacement of said actuator, at least one of said first and second orientations being a stable orientation;
and
means for causing said first movable member to move more rapidly in a first direction from the second orientation towards the unstable orientation than in a second direction from said first orientation towards the unstable orientation in response to the same amount of initial displacement of said actuator.

5 more elements

A snap action electrical switch comprising:

a hollow housing;
a displaceable actuator at least in part mounted within said housing;
at least a first movable elongated contact arm disposed within said housing, said first contact arm extending generally transversely with respect to the direction of displacement of said actuator and being rotatably coupled at one end to said actuator;
a first electrical contact means positioned within said housing, said first contact means including a first movable electrical contact mounted on said first contact arm;
at least a second electrical contact means disposed within said housing for cooperation with said first electrical contact means, said second contact means including a second stationary electrical contact;
means for establishing paths for the flow of electrical current between said first and second electrical contacts and the exterior of said housing;
means resiliently biasing said first contact arm for causing said first electrical contact to engage and disengage said second electrical contact in response to displacement of said actuator;
and
a fulcrum positioned to engage said first contact arm from a first side thereof at a point located between said first electrical contact and said one end of said arm whereby said first contact will pivot about said fulcrum only during movement of said first electrical contact towards said second electrical contact from a position where it is disengaged from said second electrical contact.

6 more elements

Dependencies are inferred from the claim text.