Washington Administrative Code › Title 204 - State Patrol (Equipment) (See also Titles 212, 446 and 448) › Chapter 204-76 - Standards for brake systems › Section 204-76-030 - Definitions

Current through Register Vol. 24-14, July 15, 2024
(1) "Air brake
			 hose" means any flexible hose used as an integral part of a service or
			 auxiliary (emergency stopping) air brake system, where flexibility in a
			 connection is mandatory due to vehicle design and includes the service and
			 emergency air hoses between vehicles in a combination of vehicles.
(2) "Air brake reservoir" means a storage
			 container for compressed air.
(3)
			 "Air compressor" means a device which compresses air used for actuation of the
			 brakes and/or other components of the vehicle.
(4) "Air gauge" means a gauge usually mounted
			 on the instrument panel which indicates the air pressure in the air reservoir
			 tanks, brake application pressure, or other air system pressures.
(5) "Air governor" means a regulator which
			 controls the supply of air pressure for the brake system, generally by
			 controlling the air compressor cut-in and cut-out pressure within a preset
			 range.
(6) "Air over hydraulic
			 brake system" means a hydraulic type brake system actuated by an air-powered
			 master cylinder.
(7) "Air pressure
			 protection valve" means a unit through which air flow is prevented except when
			 a preselected input pressure is exceeded.
(8) "Brake" means an energy conversion
			 mechanism used to retard, stop, or hold a vehicle.
(9) "Brake assembly" means an assembly of
			 brake parts, the components of which are determined according to the type or
			 design of the brake system.
(10)
			 "Brake cam" means a cam mounted on the camshaft and located between the ends of
			 the brakeshoes. When rotated by the brake camshaft, the cam expands the
			 brake-shoes against the brakedrum.
(11) "Brake camshaft" means the camshaft
			 which is held to the vehicle axle housing or backing plate by bosses containing
			 bronze or nylon bushings. Air pressure is converted into mechanical force by
			 the brake chamber which is attached by a push rod to the slack adjuster. The
			 slack adjuster multiplies the force by the lever principle and applies the
			 force to the brakeshoes.
(12)
			 "Brake chamber or actuator" means a unit in which a diaphragm converts pressure
			 to mechanical force for actuation of the brakes.
(13) "Brake cylinder" means a unit in which a
			 piston converts pressure to mechanical force for actuation of the
			 brakes.
(14) "Brake master
			 cylinder" means the primary unit for displacing hydraulic fluid under pressure
			 in the brake system.
(15) "Brake
			 pedal" means a foot-operated lever which, when actuated, causes the brake(s) to
			 be applied.
(16) "Brakeshoe" means
			 a rigid half-moon shaped device with friction material affixed to the outer
			 surface. The brake-shoes are generally mounted on a backing plate and are
			 located inside the brakedrum. When expanded by the brake mechanism, the
			 brakeshoes press the brake lining against the brakedrum, which creates friction
			 to stop the rotation of the wheels, which in turn stops the vehicle.
(17) "Brakeshoe anchor pin" means a pin which
			 holds the brakeshoe in its proper place within the brakedrum and serves as a
			 pivot for the brakeshoes. One end of each brake-shoe is generally connected to
			 the backing plate or spider by anchor pins.
(18) "Brake system" means a combination of
			 one or more brakes and the related means of operation and control.
(19) "Brake wheel cylinder" means a unit for
			 converting hydraulic fluid pressure to mechanical force for actuation of a
			 brake.
(20) "Contamination" means
			 any grease, oil, or brake fluid on the brake lining, pad friction surface, or
			 braking surface of the brake drum or rotor.
(21) "Diaphragm" means a rubber partition
			 placed between the two halves of the brake chamber. When air pressure is
			 introduced into the chamber on one side of the diaphragm, the pressure flexes
			 the diaphragm and exerts force on the pushplate attached to the push rod. The
			 pushplate is held up against the diaphragm by a light duty return
			 spring.
(22) "Disc brake" means a
			 brake in which the friction forces act on the faces of a disc.
(23) "Disc brake caliper assembly" means the
			 nonrota-tional components of a disc brake, including its actuating mechanism
			 for development of friction forces at the disc.
(24) "Disc (rotor)" means the parallel-faced
			 circular rotational member of a disc brake assembly acted upon by the friction
			 material.
(25) "Drum" means the
			 cylindrical rotational member of a drum brake assembly acted upon by the
			 friction material.
(26) "Drum
			 brake" means a brake in which the friction forces act on the cylindrical
			 surfaces of the drum.
(27) "Foot
			 valve" means a brake application and release valve located on the floor or
			 firewall of the motor vehicle between the throttle and the clutch. It may be
			 either a treadle or a pedal and is operated by foot pressure applied by the
			 driver to apply air pressure to the service brake system. The valve may be
			 either attached to the treadle or may be remotely mounted under the floor and
			 connected to the pedal by means of a rod. This valve generally applies air
			 pressure to all braking axles on all vehicles in the combination.
(28) "Hydraulic brake system" means a brake
			 system in which brake operation and control utilizes hydraulic brake
			 fluid.
(29) "Pedal reserve" means
			 the amount of total pedal travel left in reserve when the brake pedal is
			 depressed to the "brake applied" position.
(30) "Push rod" means the sliding rod
			 projecting from a brake chamber and connected to the slack adjuster by which
			 the force of compressed air in the brake chamber is transmitted to the
			 brakeshoes through connecting linkage during a brake application.
(31) "Safety valve" means a pressure release
			 unit used to protect the air system against excessive pressure.
(32) "Service brake system" means the primary
			 brake system used for slowing and stopping a vehicle.
(33) "Slack" means the sum of all clearances
			 in the braking system and total system elasticity.
(34) "Slack adjuster" means a lever attached
			 to the brake camshaft and connected to the brake chamber push rod. The slack
			 adjuster provides a means of adjusting the brakes to compensate for brake
			 lining wear.
(35) "Straight air
			 brake system" means a mechanical type brake system actuated by air pressure in
			 brake cylinders or brake chambers.
(36) "Supply air" means the air that is under
			 pressure in the air supply system of a vehicle. It consists of those lines or
			 tanks, except protected air tanks, which are under pressure when the system is
			 fully charged and when all valves are in the normal position with the brakes
			 unapplied.
(37) "Vacuum assisted
			 hydraulic brake system" means a hydraulic type brake system which utilizes
			 vacuum to assist the driver's effort to apply the brakes.
(38) "Vacuum brake reservoir" means a storage
			 container for vacuum.
(39) "Wedge
			 brake" means a wheel brake which uses air or hydraulic pressure to force wedges
			 instead of cams between the brakeshoes to apply the shoes against the
			 brakedrums. In air applied wedge brake systems, the brake actuator axis is
			 parallel to the axle and pushes directly on the wedge in this direction instead
			 of being mounted at right angles to push a slack adjuster and rotate a cam as
			 in the conventional type of air brake system.
Statutory Authority:
				  RCW
				     46.37.005. 83-21-080 (Order 83-10-01), §
				  204-76-030, filed 10/19/83; 80-10-006 (Order 80-07-01), § 204-76-030,
				  filed 7/25/80.