Patent ID: 7045724

Claim:
A jerk-initiated switch adapted to be mounted on and to be in electric contact with a support, said jerk-initiated switch comprising: an insulating housing adapted to be mounted on the support in an upright direction, and having an inner bottom wall surface, and an inner peripheral wall surface which extends upwardly from a periphery of said inner bottom wall surface and which defines an accommodation chamber therein, said inner bottom wall surface having a central area and a circumferential area surrounding said central area; a plurality of electric contact terminals displaced angularly from one another about a centerline which extends from said central area in the upright direction, each of said electric contact terminals including a shank extending in the upright direction, and a contact protrusion extending radially from said shank and having a portion protruding toward the centerline such that said portions of said contact protrusions form vertices of a polygon that defines a horizontal plane intersecting the centerline at a polygonal center, the polygon having a pair of first vertices connected by a first diagonal and a pair of second vertices connected by a second diagonal, the first and second diagonals passing through the polygonal center, and first and second polygonal sides that interconnect a corresponding one of the first vertices with the second vertices adjacent thereto, the polygonal center being distant from said central area along the centerline, the corresponding one of the first vertices, one of the two second vertices adjacent thereto, the first polygonal side, and the second polygonal side, respectively, by a height, a first diagonal section, a second diagonal section, a first length, and a second length, respectively; and an electrically conductive ball which is disposed to be rollable on said inner bottom wall surface, and which has a spherical radius of a dimension that is larger than both the height and the longer one of the first and second lengths, and that is smaller than the shorter one of the first and second diagonal sections, said central area having a topography which is configured such that said electrically conductive ball is displaced from an upright position, where said electrically conductive ball rests on said central area to establish a first switching state between two adjacent ones of said contact protrusions of said electric contact terminals through one of engagement and disengagement with said electrically conductive ball, to a jerked position, where said electrically conductive ball is jerked out of said central area to establish a second switching state between said two adjacent ones of said contact protrusions the other one of engagement and disengagement with said electrically conductive ball.