Systems and methods for a hack-proof security keyboard are described. In some embodiments, a keyboard module may include a first circuit configured to detect activation of a plurality of keys and a second circuit configured to detect activation of a subset of the plurality of keys, where the second circuit overlies the first circuit. In other embodiments, a method may include detecting an electrical signal received from a secondary membrane of a keyboard, where the keyboard includes a primary membrane configured to detect individual activation of any of a plurality of keys, and where the secondary membrane is configured to output the electrical signal in response to concurrent activation of a subset of the plurality of keys. The method may also include performing a selected action in response to the detection.

An electromagnetic relay includes a fixed spring, a fixed contact configured to be swaged so as to be attached to the fixed spring, a movable spring, and a movable contact provided on the movable spring so as to be capable of making contact with the fixed contact, wherein a swaged portion of the fixed contact is formed so as not to protrude from a surface of the fixed spring.

Switch apparatus (54), designed to detect relative movement between first and second members (60, 62), includes a switch assembly (48) comprising a switch unit (20), a biasing element (50), and an operating member (52). The unit (20) has a conductive housing (22) with first, second, and third electrical pin contacts (36-40) and a shiftable body (46). The body (46) is magnetically correlated with both the element (50) and operating member (52). When the members (60, 62) are close, the operating member (52) maintains the shiftable body (46) in one switch position, whereas when the members (60, 62) are separated, the biasing element (50) magnetically moves body (46) to another switch position, thereby detecting the relative movement).

A seat occupancy sensor includes: a first sensor group having a plurality of first sensor cells that are arrayed in a front-rear direction of a seat and become conductive as a load is applied thereto; a second sensor group having a plurality of second sensor cells that are arrayed in the front-rear direction, farther on a front side of the seat and closer to an end of the seat in a width direction than the first sensor group, and that become conductive as a load is applied thereto; and an electronic control unit. The electronic control unit determines that someone is sitting on the seat when both of at least one of the first sensor cells and at least one of the second sensor cells become conductive.

A deadman switch system includes a primary deadman switch actuator and a secondary deadman switch actuator for controlling the flow of an air/abrasive mix through a flow line of a delivery system. The secondary deadman switch is positioned in series with a primary deadman switch actuator such that the controlled flow will not function unless first the primary deadman switch and then the secondary switch are closed. The preferred embodiment of the switch is a low-profile configuration adapted to be mounted in axial alignment with the flow line in a manner to minimize interference with normal operation of the system. The switch can include multiple open/close elements, for selectively controlling different flow functions.

Provided is a relay switch device including a relay housing, a first upper fixing terminal and a second upper fixing terminal arranged side by side over an inside and an outside of the relay housing, a first lower fixing terminal electrically connected to the first upper fixing terminal and arranged under the first upper fixing terminal to be apart a predetermined distance from the first upper fixing terminal, and a second lower fixing terminal electrically connected to the second upper fixing terminal and arranged under the second upper fixing terminal to be apart a predetermined distance from the second upper fixing terminal, and a circuit mode switch module provided to selectively contact the first and second upper fixing terminals or the first and second lower fixing terminals by moving a predetermined distance.

Provided is a relay switch device including: a relay housing; a first upper fixing terminal and a second upper fixing terminal arranged side by side over an inside and an outside of the relay housing; a first lower fixing terminal electrically connected to the first upper fixing terminal and arranged under the first upper fixing terminal to be apart a predetermined distance from the first upper fixing terminal, and a second lower fixing terminal electrically connected to the second upper fixing terminal and arranged under the second upper fixing terminal to be apart a predetermined distance from the second upper fixing terminal; and a circuit mode switch module provided to selectively contact the first and second upper fixing terminals or the first and second lower fixing terminals by moving a predetermined distance.

A circuit breaker includes first and second terminals, first and second vacuum interrupters, an interconnection part, an actuator, an operating rod, and a lever system. The first terminal is connected to a fixed contact of the first vacuum interrupter. The second terminal is electrically connected to a fixed contact of the second vacuum interrupter. The interconnection part is associated with a movable contact of the first and second vacuum interrupters when the circuit breaker is in a closed state. A first end of a first lever arm is coupled to the movable contact, and a second end is coupled to the operating rod. When transitioning from an open to a closed state, the actuator moves the operating rod to move the second end of the first lever arm and the second end of the second lever arm.