The solenoid uses a push rod to actuate the sear in this system. Another common type is a float that raises a rod to actuate a microswitch. Semi trucks use air pressure, rather than hydraulic fluid, to actuate the brake. They are also often used in paintball gun triggers to actuate the CO2 hammer valve. The engine has a four-valve head with splayed rocker arms to actuate the valves. Two distinct actions are required to actuate the switches again. These cams would actuate switches to turn on the lights in sequence. Campagnolo creates Delta brakes, with a parallelogram linkage to actuate the calipers. The brakes are rod and spring operated with cams inside the drums to actuate. For example, a current loop could actuate an evacuation siren or command synchronized traffic signals. V logic level inputs to actuate a relay. In turn, muscles generate forces which actuate joints. Traditional generator protection elements typically actuate and block reclosing in about 15 cycles. By changing tones, the mobile radio would actuate a different repeater site. Not all of these disturbances spring from sectarian differences, but those differences actuate many fracases.