A spring has a dome portion having a dome shape bulging convexly, an outer peripheral portion disposed along the entire periphery of the dome portion, first and second support portions disposed at both ends of the outer peripheral portion, a valley bending portion disposed between the dome portion and the outer peripheral portion, and bent concavely upward, a first crest bending portion disposed between the outer peripheral portion and the first support portion, and bent convexly upward, and a second crest bending portion disposed between the outer peripheral portion and the second support portion, and bent convexly upward, wherein the outer peripheral portion includes a first and second side end portions which are not connected with the first and second support portions, and the valley bending portion disposed between the dome portion and the first and second side end portions extends linearly or curved inwardly in a longitudinal direction.

A spring has a dome portion having a dome shape bulging convexly, an outer peripheral portion disposed along the entire periphery of the dome portion, first and second support portions disposed at both ends of the outer peripheral portion, a valley bending portion disposed between the dome portion and the outer peripheral portion, and bent concavely upward, a first crest bending portion disposed between the outer peripheral portion and the first support portion, and bent convexly upward, and a second crest bending portion disposed between the outer peripheral portion and the second support portion, and bent convexly upward, wherein the outer peripheral portion includes a first and second side end portions which are not connected with the first and second support portions, and the valley bending portion disposed between the dome portion and the first and second side end portions extends linearly or curved inwardly in a longitudinal direction.

A spring has a dome portion having a dome shape bulging convexly, an outer peripheral portion disposed along the entire periphery of the dome portion, first and second support portions disposed at both ends of the outer peripheral portion, a valley bending portion disposed between the dome portion and the outer peripheral portion, and bent concavely upward, a first crest bending portion disposed between the outer peripheral portion and the first support portion, and bent convexly upward, and a second crest bending portion disposed between the outer peripheral portion and the second support portion, and bent convexly upward, wherein the outer peripheral portion includes a first and second side end portions which are not connected with the first and second support portions, and the valley bending portion disposed between the dome portion and the first and second side end portions extends linearly or curved inwardly in a longitudinal direction.

A spring has a dome portion having a dome shape bulging convexly, an outer peripheral portion disposed along the entire periphery of the dome portion, first and second support portions disposed at both ends of the outer peripheral portion, a valley bending portion disposed between the dome portion and the outer peripheral portion, and bent concavely upward, a first crest bending portion disposed between the outer peripheral portion and the first support portion, and bent convexly upward, and a second crest bending portion disposed between the outer peripheral portion and the second support portion, and bent convexly upward, wherein the outer peripheral portion includes a first and second side end portions which are not connected with the first and second support portions, and the valley bending portion disposed between the dome portion and the first and second side end portions extends linearly or curved inwardly in a longitudinal direction.

A switch mechanism has a compliant buckling bar that includes a single fixed end mounted to a mounting surface and a free end that is displaced with respect to the fixed end. The mounting of the fixed end to the mounting surface may constitute the only fixed connection between the bar and the mounting surface. The bar moves between two stable positions in response to a transition force applied transversely to the free end. Residual stress in the bar may be higher when the free end is at each of the stable positions than when the free end is at a neutral position located between the stable positions.

A pressure switch including: a spring blade; a ram pin having an angled bottom surface and laterally restrained in movement, where upward movement of the ram pin engages the spring blade such that the spring blade snap deflects to an engaged position, and where downward movement of the ram pin engages the spring blade such that the spring blade snap deflects to an unengaged position; a ball bearing in contact with the angled bottom surface of the ram pin; and an adjustment screw laterally restraining the ball bearing in movement, where a lateral inward movement of the adjustment screw relative to an outside surface of the pressure switch causes an upward movement of the ram pin, and where a lateral outward movement of the adjustment screw relative to the outside surface of the pressure switch causes a downward movement of the ram pin.

A fixed core includes: a fixed core tapered portion having a diameter increased in an attraction direction; and a fixed core circular portion having a fixed outer diameter and extending in the attraction direction from an end of the fixed core tapered portion. A movable core includes a movable core tubular portion in which a movable core hole is defined. The movable core hole is a space into which the fixed core tapered portion and the fixed core circular portion can enter. The movable core tubular portion includes: a movable core cylindrical portion having a constant inner diameter; and a movable core tapered tubular portion having an inner diameter decreased from an end of the movable core cylindrical portion in a non-attraction direction.