Conducting fluid type inertia responsive switch for motor vehicles

Claim 1

An automatic cutout switch for motor vehicles, comprising a housing at least partially of non conducting material and mountable in a fixed position on said motor vehicle, said housing having a normally vertical axis, a closed lower end portion and an open upper end portion, a cover removably mounted on said housing for closing said open upper end within said housing: first wall means defining a first compartment for mercury having a closed bottom portion and an open top portion, said first wall means having a first wall portion thereof surrounding said first compartment and extending parallel to said vertical axis from said bottom portion upwardly and terminating with said open top end thereof at a distance below said open upper end portion said first wall portion having a surface facing said first compartment said surface being cylindrical and extending parallel to said vertical axis, secOnd wall means defining a second compartment having an annular bottom surrounding said open top portion of said first compartment, said annular bottom being at a higher level than the bottom portion of said first compartment and at a lower level than the open top portion of said first compartment, the upper end of said second compartment coinciding with the upper open end of said housing, a lid normally closing said open top portion of said first compartment normally to prevent leakage of mercury therefrom, biasing means yieldably urging said lid into its closing position, said biasing means providing a preestablished closing force acting on said lid, and yieldable under the action of a pre-established impact intensity created under emergency conditions, guide means for said lid for guiding said lid from an open position thereof into its closing position under the action of said biasing means, a pair of electrically conducting contact members opening into said first compartment at opposite sides thereof at a distance from each other, thereby to allow the mercury contained in said first compartment to provide the only electrical contact between said contact members, one of said contact members being connectable to one of the terminals of the electrical power source of the motor vehicle and the other of said contact members being connectable to an electrical current distribution cable, normally closed passage means allowing, in open condition, communication between said bottom portion of the first compartment and said annular bottom of said second compartment thereby to allow mercury temporary contained in said second compartment to flow into said first compartment, and removable means for maintaining said passage means normally in closed conditions.