A centrifugal friction clutch is provided which includes a first friction member to be fixed on a rotary shaft; a support portion to be fixed on the rotary shaft; a centrifugal device disposed on the support portion, the centrifugal device including a cam portion and a centrifugal arm extending the cam portion, the cam portion being rotating relative to the support portion when the centrifugal arm moves; and a friction connecting member disposed between the first friction member and the support portion. When the support portion rotates along with the rotary shaft, a free end of the centrifugal arm moves radially outwardly under a centrifugal force and drives the cam portion to rotate, the cam portion urges the friction connecting member toward the first friction member when the cam portion rotates.

An actuator primarily activated by transversal acceleration arising from rotational acceleration of a rotatable object is presented. The object is rotatable in a plane of rotation (P) about an object pivot point in the plane of rotation (P). The actuator comprises at least two bodies adapted to be rotatably, in or parallel to the plane of rotation (P), coupled to the object at a body pivot point of each body. The body pivot point and/or the body is arranged such that a mass distribution of the body is nonuniform about the body pivot point. Due to the nonuniform mass distribution about the body pivot point, the actuator is configured to transition to an activated state, in response to rotational acceleration of the object, by the at least two bodies rotating about their respective body pivot points in a direction opposite to a direction of the rotational acceleration of the object.

An actuator primarily activated by transversal acceleration arising from rotational acceleration of a rotatable object is presented. The object is rotatable in a plane of rotation (P) about an object pivot point in the plane of rotation (P). The actuator comprises at least two bodies adapted to be rotatably, in or parallel to the plane of rotation (P), coupled to the object at a body pivot point of each body. The body pivot point and/or the body is arranged such that a mass distribution of the body is nonuniform about the body pivot point. Due to the nonuniform mass distribution about the body pivot point, the actuator is configured to transition to an activated state, in response to rotational acceleration of the object, by the at least two bodies rotating about their respective body pivot points in a direction opposite to a direction of the rotational acceleration of the object.