Pushbutton-actuated excess-current switch

摘要

A bell-crank-like switching connector is supported on a switch rod having a pushbutton such that it is pivotable and is displaceable along the switch rod. A first lever arm of the switching connector is lockable underneath a protrusion of a bimetallic strip. A second arm bears a contact piece associated with a fixed contact piece. Tabs protrude beyond a latching edge of the first lever arm and upon switching on of the switch they slide over lateral regions of an associated latching edge of the protrusion of the bimetallic strip and thereby make a wear-producing mechanical contact of the two latching edges impossible. The switching connector is exposed to the pressure of a switch spring coaxial with the switch rod. A button spring acting upon the pushbutton and having a substantially smaller spring rate is likewise disposed coaxially with the switch rod and is supported on the switching connector. The contact pressure and the contact separating force are therefore determined practically only by the switch spring. For switching the switch on, the end face of the switch rod presses upon an extension of the second lever arm running on a housing projection, in order to make the contact piece of the second lever arm approach the fixed contact piece and to reduce contact chatter. A recess in the switch rod for the extension causes a long spacing distance between the contacts to be maintained in an unintended tripping position of the switch.