DICTIONARY OF AUTOMOTIVE TERMS - "Br"

Bra:

A protective cover, usually of leather or vinyl, which is mounted to the front of a vehicle to protect the finish from stones.
Also See:
stealth Bra

Brace:

1. A support beam to give reinforcement between two objects.
2. A member connecting two nodes of a structure out of plane with the main members, for stiffening purposes. Depending on the applied loads it may be subject to tensile or compressive forces. Also called swaybrace.

Also See:
roof brace
speed brace

Bracing:

1. To stiffen something by using a brace.
2. The staying or supporting rods or ties which are used in the construction or strengthening of a structure.
3. A brace.
   Also See:
   cross bracing

Bracing wires:

The wires used to support the wings of biplanes and the earlier monoplanes.
Also See:
drag wires
landing wires

Bracket:

A support device which is often a right-angled shape.
Also See:
angle bracket
bilge bracket
bottom bracket
bumper bracket
drive end bracket
end bracket
fender support bracket
margin bracket
slip-ring end bracket
spring bracket
towing bracket
tripping bracket
wing support bracket

Bracket arms:

The transverse projecting arms on the poles, for supporting the overhead contact wire equipment for a tramway or railway system.

Bracket set:

See:
chassis bracket set

Bracket shell:

See:
bottom bracket shell

Bracket spindle:

See:
bottom bracket spindle

Bragg angle:

The angle the incident and diffracted X-rays make with a crystal plane when the Bragg equation is satisfied for maximum diffracted intensity.

Bragg curve:

Graph giving average number of ions per unit distance along beam of initially monoenergetic alpha particles (or other ionizing particles) passing through a gas.

Bragg diffraction:

Diffraction of X-rays according to the Bragg equation

Bragg rule:

An empirical relationship according to which the mass stopping power of an element for alpha particles (also applicable to other charged particles) is proportional to (relative atomic mass) ^-05

Bragg's law:

See:
Bragg equation

Braided hose:

A rubber hose which is covered in a woven material or braided wire. Used for various hoses under the hood.

Brake:

1. To slow down a vehicle.
2. The mechanism that converts motion ( kinetic energy) into heat energy through friction. The most common instance is found in the wheels of cars where the brake shoes or disc pads are designed to press against the brake drum or brake disc.

Also See:
action brakes
air brake
anti-lock brakes
anti-lock brake system
armature brake
assisted brakes
band brake
bleeding the brakes
block brake
bonded brake lining
cable brake
caliper disc brake
cantilever brakes
clutch brake
coaster brake
disc brake
disc brake gauge
disc brake rotor
disc brakes
double leading brake shoe
drum brake
dual brakes
duo-servo brake
E-brake
emergency brake
engine brake
fixed-caliper disc brake
fixed-cam brake
flexible brake pipe
floating caliper disc brake
flushing the brakes
foot brake
forward brake shoe
four wheel disc brakes
high-mounted brake light
hinged-caliper disc brake
hub brake
hydraulically-activated brakes
hydraulically-assisted brakes
hydraulic assisted brakes
hydraulic brake booster
hydraulic brakes
inboard brake
jake brake
jam on the brakes
jam the brakes
juice brake
leading brake shoe
low brake pedal
master brake cylinder
maximum brake power
mechanical brakes
non-servo brake
park brake
park brake extension
parking brake console
parking brake lever strut
parking brake lever
parking brake pedal
parking brake
pin slider caliper disc brake
power assisted brakes
power brake
press brake
primary brake shoe
primary forward brake shoe
prony brake
pumping the gas brakes
pump the brakes
reverse brake shoe
rim brake
riveted brake lining
rollercam brake
self-energizing brake shoe
service brake
servo action brake
servo brake
shooting brake
single-anchor self-energizing brake
sliding-caliper disc brake
sprag brake
spring brake
U-brake
uni-servo brake
vacuum assisted brake
ventilated brakes

Brake actuator:

A unit which converts hydraulic pressure, air pressure, vacuum, or electrical current or other forms of energy to a force which applies a brake.

Brake adjuster:

1. A device which moves the brake drum shoes closer to or further apart from the drum.
2. A device or mechanism used to set and maintain the proper clearance between the brake lining and drum.

Brake adjusting spanner:

A British term for brake wrench

Brake adjusting wrench:

A wrench which is used to adjust the brake shoes.

Brake anchor:

A steel stud or pin upon which one end of the brake shoes is either attached to or rests against. The anchor is firmly affixed to the backing plate.

Brake, anti-lock:

See:
anti-lock brakes

Brake antiroll device:

See:
brake anti-roll device

Brake anti-roll device:

A unit installed in the brake system to hold brake line pressure when the vehicle is stopped on an upgrade, when the vehicle is stopped on the upgrade and the brake pedal released, the anti-roll device will keep the brakes applied until either the clutch is released or as on some models, the accelerator is depressed.

Brake assembly:

An assembly of the non-rotational components of a brake including its mechanism for development of friction forces.

Brake backing plate:

A rigid metal (steel) plate, located inside the brake drum, on which the wheel cylinder, brake shoes, and other brake parts are mounted. The braking force applied to the shoes is absorbed by the backing plate.

Brake balance:

1. The ratio of front-to-rear braking force.
2. The split of braking power between the front and rear axles. Proper brake balance allows the driver to use the full braking ability at all four wheels when stopping the car.

Brake band:

1. A band, faced with brake lining, that encircles a brake drum, it is used on several parking brake installations. It differs from brake shoes in that brake shoes squeezes against the inside surface of a drum while a brake band squeezes against the outside surface of a drum.
2. A flexible circular metal band which surrounds a brake drum and contracts around it to create the friction necessary to stop the vehicle. The rubbing surface of a brake band is faced with a brake lining material.

Brake bias:

The front/rear distribution of a vehicle's braking power. For the shortest stopping distance, brake bias should match the vehicle's traction at each end during hard braking brake modulation -- the process of varying pedal pressure to hold a vehicle's brakes on the verge of lockup. Ideally, the brakes will unlock with only a slight reduction in the pressure needed to lock them. Typically, however, a considerable pressure reduction is required.

Brake bleeder:

A valve attached to each wheel brake. This valve can be opened and closed to allow air to be removed or bled from the brake lines.

Brake bleeding:

See:
bleeding the brakes

Brake block:

A molded piece of friction material attached to shoes and pads to serve as the brake lining.
See:
brake pad

Brake booster:

1. A mechanical device which attaches to the brake system to multiply the force the driver applies with his foot (or hand as in the case of a motorcycle). The device uses air, vacuum, or hydraulic fluid to accomplish this purpose. Sometimes called "power assisted brakes," "vacuum assisted brakes," "hydraulically assisted brakes," or just "power brakes." In most cars, the boost comes from engine intake vacuum. In motorcycles it comes from hydraulic fluid.
2. A device utilizing a supplementary power source to reduce pedal (or lever) force in a hydraulic brake system.
3. An arch (usually built from aluminum or carbon fiber) which attaches to the brake bosses of a bicycle in conjunction with the brake. The powerful braking force of V-Brakes or linear pull brakes can cause frames and forks to flex and waste energy which could have been applied to the rims. The booster acts as a brace to prevent frame flex induced during braking.

Also See:
hydraulic brake booster
vacuum brake booster

Brake boss:

The brazed-on pivots attached to frames and forks for cantilever and "V" style brakes. Shift lever bosses are brazed-on pivots for down-tube-mounted shift levers. Most newer "road" bicycles have the shifters mounted on the handlebars, so they use the old-style lever bosses as attachment points for housing stops.

Brake cable:

1. A wire cable which activates the brakes. Used on motorcycles, trailers, and automobile parkbrakes.
2. A wound steel cable running from the brake levers of a bicycle to the brake calipers.

Brake cable housing:

The outer, colored housing into which a brake cable is inserted.

Brake caliper:

1. The component of a disc brake that converts hydraulic pressure into mechanical energy.
2. The device in a disc brake that converts hydraulic pressure back into the mechanical force used to apply the brake pads against the rotor.

Also See:
calipers

Brake chamber:

A unit in which a diaphragm converts pressure to mechanical force for actuating a brake.

Brake check:

Trucker slang for jamming on your brakes in traffic as in "Watch out we're doing a break check up ahead."

Brake check valve:

See:
check valve

Brake console:

See:
parking brake console
computer brake control

Brake controller:

See:
anti-lock brake controller

Brake cylinder:

1. A cylinder containing a movable piston actuated by hydraulic pressure to push fluid through the lines and wheel cylinders and force the brake lining or pads against a drum or disc.
2. A unit in which a piston converts pressure to mechanical force for actuation of a brake.

Also See:
wheel cylinder
master brake cylinder

Brake disc:

1. The component of a disc brake that rotates with the wheel and is squeezed by the brake caliper and pads, which creates friction and converts the energy of the moving vehicle into heat.
2. The parallel-faced, circular, rotational member of a brake acted upon by the friction material.
3. A British term for brake rotor.

Brake disc type:

A braking system that instead of using the conventional brake drum with internal brake shoes, uses a steel disc with caliper type lining application, when the brakes are applied, a section of lining on each side of the spinning disc is forced against the disc thus imparting a braking force. This type of brake is very resistant to brake fade.
Also See:
disc brake.

Brake dive:

The action of the front end of a vehicle as it dips down when the brakes are applied. Opposite to squat.
Also See:
anti-dive system
anti-lift
anti-squat system

Brake drag:

Failure of the brakes to release completely when the driver's foot is removed from the pedal.

Brake drum:

1. A cast iron or aluminum housing bolted to the wheel, that rotates around the brake shoes. When the shoes are expanded, they rub against the machined inner surface of the brake drum and exert a braking effect upon the wheel to slow or stop the vehicle. In some cases an external band surrounds the drum to reduce the motion of the wheel.
2. The rotating cylindrical component of a drum brake system on which the brake shoes act to slow or stop the vehicle.

Brake drum lathe:

A machine to refinish the inside of a brake drum.

Brake dust:

The dust created as the brake linings wear down in normal use. Brake dust usually contains dangerous amounts of asbestos.

Brake dynamometer:

A device that measures the power and torque of an engine by restricting its speed (braking) so as to gauge its output

Brake effectiveness buildup:

A temporary increase in brake effectiveness during a stop or snub.

Brake efficiency:

The retarding force expressed as a percentage of the total vehicle weight

Brake extension:

See:
park brake extension

Brake fade:

1. Reduction or loss in braking force due to loss of friction between brake shoes and drum (or brake pads and disc). Caused by heat buildup through repeated or prolonged brake application.
2. The partial or total loss of braking power that occurs when excessive heat reduces friction between the brake linings and the rotor or drum.

Also See:
heat fade
water fade

Brake failure:

The total inability of the brakes to function. May be caused by worn out pads or shoes, broken hydraulic lines, broken cable or other linkage, non-functioning master cylinder, low or empty brake fluid reservoir, etc.

Brake feel:

A discernible, to the driver, relationship between the amount of brake pedal pressure and the actual braking force being exerted. A special device is incorporated in power brake installations to give the driver this feel.

Brake fluid:

A special fluid used in hydraulic brake systems to stop or slow the vehicle. Never use something else in place of regular fluid. There are four types of brake fluid on the market. DOT 3, DOT 4, DOT 5, and DOT 5.1.
Also See:
silicone brake fluid

Brake fluid level indicator:

A unit in a hydraulic brake system which indicates the amount of brake fluid.

Brake fluid level warning switch assembly:

A unit used to actuate a warning device indicating a reservoir fluid level lower than a preset value.

Brake fluid reservoir:

In an automobile, it is a translucent tank located in front of the master cylinder. It usually has two chambers containing brake fluid. In a motorcycle, it may be found on the handlebar (for the front brake) or near the back of the bike (for the rear brake).

Brake flushing:

Cleaning the brake system by flushing with alcohol or brake fluid. This is done to remove water, dirt, old brake fluid, or any other contaminant. Flushing fluid is placed in the master cylinder and forced through the lines and wheel cylinders where it exits at the cylinder bleed screws.

Brake gauge:

See:
disc brake gauge

Brake hood:

A plastic, rubber, or leather covering mounted around the brake levers to keep out the dust and to provide a non-abrasive placement for the hands during cycling

Brake horsepower:

(bhp) A measurement of the actual usable power (not calculated power) measured at the output shaft (usually the crankshaft) rather than at the driveshaft or the wheels. Thus none of the auxiliaries (gearbox, generator, alternator, differential, water pump, etc.) are attached. It is called the brake horsepower because the shaft power is usually measured by an absorption dynamometer or "brake." This is not the brake on the vehicle's wheels but a testing device applied to the shaft. This instrument is applied to stop or absorb the rotation of the output shaft and returns a value. One bhp = 746W or (approx) 3bhp = 4kW. Compare SAE gross horsepower and SAE net horsepower.
Also See:
horsepower

Brake hose:

A flexible high-pressure hose that is reinforced. It connects between the brake pipes and the brake assembly. It needs to be flexible because of the constant movement of the suspension.

Brake hose coupler:

A separable mechanical connector for a brake hose between the towing and the towed vehicle.

Brake lathe:

1. The machine used to resurface the friction surfaces of brake discs or drums.
2. A machine used to refinish brake drums and disc brake rotors.

Brake handle:

A hand-operated lever which, when actuated, causes the brake(s) to be applied.

Brake lever:

1. A blade attached to the right side of a motorcycle handlebar which usually activates the front brake.
2. A device for activating the park brake.
3. A curved blade found on either side of a bicycle handlebar which activates the front or rear brakes.
   

Also See:
parking brake lever

Brake lever strut:

See:
parking brake lever strut

Brake light:

A red light at the rear of the vehicle which is activated when the brakes are applied. Also called "stop light."
Also See:
high-mounted brake light
auxiliary brake lights

Brake light switch:

An electrical switch, operated either mechanically or hydraulically (depending on the car) causes the brake lights to come on when the brakes are activated.

Brake line:

See:
brake lines

Brake lines:

1. A system of hoses and metal tubes through which the brake fluid flows from the master cylinder to the brake calipers at each wheel. Cracks or breaks in these lines will cause the fluid to leak out and result in loss of brakes.
2. Small-diameter rigid steel tubing used to channel hydraulic pressure from the master cylinder to the wheel cylinder or caliper in a brake system. May have either a double or ISO flaring at fittings.

Brake lining:

1. A heat-resistant friction material (usually asbestos) that is attached to the brake shoe (either riveted or bonded). When the shoe is pressed against the brake drum, the lining grabs the inside of the drum, which stops the vehicle and also prevents the drum and the shoe from wearing each other away.
2. A special friction material with which brake shoes or brake pads are lined. It withstands high temperatures and pressures. The molded material is either riveted or bonded to the brake shoe, with a suitable coefficient of friction for stopping a vehicle.

Also See:
bonded brake lining
riveted brake lining

Brake lining wear sensor:

A unit used to actuate a warning device indicating a brake lining thickness less than a preset value.

Brake lock:

See:
steering wheel and brake lock

Brake magnet:

A permanent magnet or electromagnet which produces a braking effect, either by inducing eddy currents in a moving conductor or by operating a mechanical brake by means of a solenoid.

Brake master cylinder:

The part of the hydraulic brake system which stores the brake fluid. As the brake pedal is applied pressure is forced against a small movable piston in the master cylinder to push hydraulic fluid through the lines to the wheel cylinders and force the brake linings against the drum (in the case of drum brakes) or force the brake pads against the disc (in the case of disc brakes).

Brake mean effective pressure:

(BMEP)

1. The average pressure in the cylinders of an engine divided by its mechanical efficiency, i.e., the ratio of the power actually delivered at an output shaft to the power developed in the cylinders. It is used as an indication of torque.
2. That part of the indicated mean effective pressure (IMEP) developed in an engine cylinder output equal to the brake horsepower of the engine; the product of IMEP and mechanical efficiency.

Brake pad:

1. The friction material or lining which is secured to metal plates. They press against the brake disc or rotor to enable the wheel to stop. They are to be distinguished from brake shoes which press against the inside of a drum.
   
2. On a bicycle, brake pads are blocks of rubber-like material fastened to the end of the brake caliper; they press against the wheel rim when the brakes are applied. Also called brake block. Sometimes the term "brake pad" refers to both the pad and the metal backing.

Also See:
ceramic brake pad
sintered metal brake pad

Brake pads:

See:
brake pad

Brake pad wear indicator:

A device which detects the thickness of the brake pad by using an L-shaped strap which will scrape against the disc when the pad thickness is below tolerance. Others use an electrical circuit in which a worn pad closes an electrical circuit that illuminates a light on the dash panel.

Brake parachute:

Parachute attached to the tail of some high-performance aircraft and streamed as a brake for landing. Sometimes a ribbon canopy is used for greater strength and on large aircraft a cluster of two or three is required to give sufficient area with convenient stowage. Also called landing parachute and parabrake

Brake pedal:

A foot operated device which engages the brakes to stop or slow the rotation of the wheels.
Also See:
low brake pedal
parking brake pedal
spongy brake pedal

Brake pipe:

A steel pipe used to transmit the brake fluid.
Also See:
flexible brake pipe

Brake piston:

On a motorcycle, pressure from the brake lever (when squeezed) forces the brake fluid to flow from the master cylinder down through the brake line and into the caliper. The pressure of the brake fluid causes the piston to push the brake pad to rub against the disc, thus stopping movement of the motorcycle.

Brake piston tool:

A disk brake tool used to rotate the piston back into the caliper when replacing pads

Brake, power:

See:
power brakes
maximum brake power

Brake power assist:

A device installed in a hydraulic brake system that reduces pedal effort.

Brake pressure modulator valve:

(BPMV) A combined assembly of the electronic control unit and hydraulic control unit, used in tome GM vehicles, Also called the Electro-Hydraulic Control Unit (EHCU).

Brake puck:

See:
brake pads

Brake pucks:

See:
brake pads

Brake pulling:

A situation where the vehicle moves to one side when the brakes are applied. It is usually due to uneven application of the brakes from side to side.

Brake, parking:

See:
parking brake
emergency brake

Brake proportioning valve:

A valve that limits braking force to the front or rear wheels, usually as a function of pedal effort or line pressure, loading of the vehicle or front-rear weight transfer, to prevent wheel locking and provide the most effective braking.

Brake retarder:

An auxiliary energy conversion system used to supplement the service brake unit on a moving vehicle.

Brake rod:

A long rod which connects between the brake pedal and the brake actuating lever.

Brake rotor:

The brake disc which is attached to the wheel and is surrounded by a brake caliper.
Also See:
disc brake rotor

Brakes, antilock:

See:
anti-lock brakes

Brakes, anti-lock:

See:
anti-lock brakes

Brakes, cantilever:

See:
cantilever brakes

Brake servo:

A device which multiplies the driver's physical effort in applying the brakes by using manifold vacuum.

Brake servo unit:

See:
brake servo

Brake shoe:

1. That part of the brake system, located at the wheels, upon which the brake lining is attached. There are usually two shoes (curved or arc-shaped pieces) in each wheel. When the wheel cylinders are actuated by hydraulic pressure they force the brake shoes apart and bring the lining into contact with the brake drum. In this way the vehicle is slowed or stopped. On a bicycle, it is the metal part that holds a brake pad and is bolted to the end of a brake caliper.
2. A crescent-shaped (for drum brakes) or a square/rectangular (for disc brakes) piece of metal faced with brake lining material and forced against the revolving drum or disc to create friction. In a disc brake system, the brake shoe may be called a brake pad.

Also See:
double leading brake shoe
forward brake shoe
leading brake shoe
primary brake shoe
primary forward brake shoe
reverse brake shoe
secondary brake shoe
self-energizing brake shoe
single leading brake shoe
trailing brake shoe.

Brake shoe grinder:

A grinder used to grind brake shoe lining so that it will be square to and concentric with the brake drum.

Brake shoe heel:

That end of the brake shoe closest to the anchor bolt or pin.

Brake shoe hold-downs:

Spring-loaded retainers that hold brake shoes against the backing plate.

Brake shoe return spring:

A spring which is attached to the two brake shoes. After the brake is applied, this spring pulls the shoes away from the drum.

Brake shoes:

The components of a drum brake assembly that are surfaced with brake lining and forced against the brake drum to generate friction.

Brake shoe toe:

The free end of the shoe, it is not attached to or resting against an anchor pin.

Brake sidepull:

See:
sidepull brake

Brakes linear pull:

See:
linear pull brakes

Brake snub:

The act of retarding a motor vehicle between two positive speed values by the use of a brake system

Brake snubbing time:

Time elapsed during a brake snub from the start of brake application to the instant the lower speed value is reached.

Brakes, power:

See:
power brakes

Brake stopping distance:

Distance travelled by a motor vehicle from the start of a brake application to the point at which the motor vehicle reaches a complete stop.

Brake stopping time:

Time elapsed by a motor vehicle from the start of a brake application to the instant the motor vehicle reaches a complete stop

Brakes V:

See:
V brakes

Brake system:

A system that uses hydraulic pressure to enable your vehicle to slow and stop safely. Consists of the master cylinder, brake lines, and disc or drum brakes at each wheel.
Also See:
anti-lock brake system

Brake system actuation distance:

The distance travelled between the start of brake application and the instant at which a specified brake system pressure is obtained

Brake system actuation time:

The time elapsed between the start of brake application and the instant at which a specified brake system pressure is obtained

Brake system cleaner:

A type of solvent designed exclusively for cleaning brake system components. It will not destroy plastic, rubber, or synthetic rubber components and it dries quickly, without leaving a residue.

Brake test:

A testing procedure which determines the efficiency of a vehicle's brakes in order to pass safety tests.

Brake thermal efficiency:

The efficiency of an engine reckoned in terms of the brake horsepower; given by the ratio of the heat equivalent of the brake output to the heat supplied to the engine in the fuel or steam.

Brake torquing:

A procedure generally used in performance tests to improve the off-the-line acceleration of a vehicle equipped with an automatic transmission. It is executed by firmly depressing the brake with the left foot, applying the throttle with the vehicle in gear to increase engine rpm, then releasing the brakes. Brake torquing is particularly effective with turbocharged cars because it helps overcome turbo lag.

Brake warning light:

An indicator light on the dash which indicates problems such as low fluid level in the brake fluid reservoir, a malfunction in any of the hydraulic brake circuits, or excessive wear of the brake pads or shoes. It also illuminates when the parkbrake is applied. When the ignition is first started, the light will illuminate momentarily to show that the light is working.

Brake wrench:

A wrench which is used to adjust the brake shoes. The British call it a "brake adjusting spanner."

Braking:

The action of operating the devices for slowing the motion of a vehicle.
Also See:
active braking time
aerodynamic braking
all-out braking
cadence braking
diagonal split braking system
dual-circuit braking system
dual-line braking system
dual braking system
engine braking effect
heavy braking
hydraulic braking system
late braking
light braking
regenerative braking
stab braking
trail braking

Braking distance:

A measurement of the distance that a vehicle will travel from the time the brakes are first applied to the actual moment it stops.
Also See:
stopping distance

Braking effect:

See:
engine braking effect

Braking efficiency:

Braking effort as a percentage of the weight of the vehicle.

Braking effort:

The amount of strength needed by the operator to bring a vehicle to a stop or the amount of resistance in the brake system.

Braking force:

The amount of strength needed by the operator to bring a vehicle to a stop or the amount of resistance in the brake system.

Braking force ratio:

The sum of the retarding forces developed by each braked wheel divided by the "as tested" gross mass of the vehicle or combination.

Braking notches:

Positions of the angle of a drum-type controller which apply some form of electric braking.

Braking ratio:

The distribution of braking effort between the front and rear wheels.

Braking system:

All the components that contribute to stopping the vehicle.
Also See:
anti-lock braking system
diagonal split braking system
dual-circuit braking system
dual-line braking system
dual braking system
hydraulic braking system
secondary braking system
single-circuit braking system
single-line braking system

Braking time:

See:
active braking time

Braking Torque:

1. The torque required to bring an electric motor down from running speed to a standswtill.
2. The torque developed by an electric motor during dynamic braking conditions

Branch:

1. An alternative mode of radioactive decay.
2. Electric components comprising a minimum path between junction points of common connection in a network. Also called arm
   See:
   acoustic branch

Branch-circuit:

A circuit branched off a main circuit.

Branch exchange:

See:
private branch exchange

Branching:

The existence of two or more modes or branches by which a radionuclide an undergo radioactive decay, e.g., copper-64 can undergo β ^- , β ⁺ and electron-capture decay

Branch jack:

See:
jack

Branch switch:

A term used in connection with electrical installation work to denote a switch of any type for controlling the current in a branch circuit.

Brand number:

A series of identifying numbers and letters which some companies burn into the sidewall rubber of a truck tire to show their initials, mounting date, etc.

Brasilsat:

A Brazilian communications satellite system

Brass:

An alloy of copper and zinc, but other elements such as aluminum, iron, manganese, nickel, tin, and lead are frequently added. There are numerous varieties.
Also See:
admiralty brass alpha brass
alpha-beta brass
beta brass
copper alloys

Brasses:

Those parts of a bearing which provide a renewable wearing surface; they consist of a sleeve or bored block of brass split diametrally, the two halves being clamped into the bearing block by a cap.

Brass hammer:

A hammer with a brass head which is used to pound steel pins etc. into place without damaging them because the brass head is softer than steel.

Brass punch:

A drift or punch made of brass which is used to remove bushings and bearing races because brass does not score or mark steel.

Braun tube:

Original name for cathode-ray tube, after K. F. Braun (1850-1918) the inventor.

Brayton cycle:

A constant-pressure cycle of operations used in gas turbines.

Braze:

To join two pieces of metal together by heating the edges to be joined and then melting drops of brass or bronze on the area. Unlike welding, this operation is similar to soldering, except a higher melting point material is used.

Braze on:

See:
braze-ons

Braze-on:

See:
braze-ons

Braze-ons:

Parts for mounting shift levers, cable guides, pump pegs, chain hangers, front and rear eyelets, derailleurs, water bottle cages, and racks, which are fastened to a bicycle frame through a type of soldering process known as brazing.

Braze welding:

Making an adhesion groove, fillet, or plug connection with a brazing alloy.

Brazing:

Making an adhesion groove, fillet, or plug connection with a brazing alloy, brass, spelter, or brazing solder between the adjoining surfaces.

Brazing solders:

Alloys used for brazing. They include copper-zing (50-55% copper), copper-zinc-silver (16-52% copper, 4-38% zinc, and 10-80% silver), and nickel-silver alloys.

Brazing flux:

Substance applied to surfaces to be joined by brazing or soldering to keep oxides from forming and to produce joints.

Breadth:

See:
beam

Breadth coefficient:

See:
distribution factor

Breadth factor:

See:
distribution factor

Break:

1. The action of an item when it no longer holds integrity -- usually resulting in unusable pieces.
2. The shortest distance between the contacts of a switch, circuit breaker, or similar apparatus, when the contacts are in the fully open position.
3. To dismantle a vehicle for parts.
4. To separate as when a switch breaks contact when it is shut off
5. Trucker slang for "I'd like to break-in" or "interrupt" as in "Can I get a break."

Also See:
air break
impact break
circumferential break

Break-10:

Trucker slang for "I want to talk (on channel 10)" as in "Can I get a break one-oh."

Break away:

See:
breakaway

Breakaway:

The action of a wheel when it turns very rapidly and loses traction so that there is no contact with the ground. Bias-belted tires and radial tires resist the breakaway action better than a bias ply tire.
Also See:
spark breakaway

Breakaway barricade:

A road obstruction which is designed to warn motorists that the road is unpassable or that there is construction in a particular lane. It is easily dismantled (thus "breakable").

Breakbulk vessel:

A general, multipurpose, cargo ship that carriers cargoes of nonuniform sizes.

Break down:

1. To cease to operate as in our car broke down on the highway.
2. To lose its insulating effectiveness. The sudden passage of current through an insulating material at breakdown voltage.

Breakdown:

1. A failure of a mechanism or vehicle as in we had a breakdown on the highway.
2. A loss of insulating effectiveness. The sudden passage of current through an insulating material at breakdown voltage.

Breakdown crane:

A portable jib crane carried on a railway tram or tow-truck, for rapid transit to the scene of an accident.

Breakdown diode:

See:
zener diode

Breakdown recovery:

Rescue of a vehicle that has suffered a breakdown by towing it to a service station, etc.

Breakdown service:

A service provided by a tow-truck in providing repairs at the place where the breakdown occurred.

Breakdown Torque:

The maximum torque of an electric motor that will develop at rated voltage without a relatively abrupt drop or loss in speed

Breakdown truck:

A tow-truck.

Breakdown voltage:

(BDV) The potential difference at which a marked increase in the current through an insulator or a semiconductor occurs.
Also See:
disruptive voltage
anode breakdown voltage

Breaker:

1. A person who dismantles a vehicle for parts. Also called a dismantler.
2. A cushioning layer between the belt layers and the tread in radial tires.
3. A device for removing contact.
4. A circuit breaker
5. The tread bracing part of tire.
6. Trucker slang for a CB'er who asks to use a channel as in "Who's that breaker out there."

Also See:
bead breaker
chain breaker
circuit breaker
dual breaker points
glaze breaker

Breaker arm:

The movable part of a pair of contact points in a distributor or magneto.

Breaker cam:

The lobed cam rotating in the ignition system which interrupts the primary circuit to induce a high tension spark for ignition.

Breaker gap:

See:
contact breaker gap

Breaker plate:

1. The movable plate inside the distributor to which the points and the condenser are attached.
2. Device fitted in front of the extruder screw to aid mixing.

Also See:
contact breaker plate
extrusion

Breaker point:

See:
breaker points
contact breaker point

Breaker point distributor:

An older style of distributor which used breaker points to act as an on-off switch to interrupt current flow through the primary winding of the coil. It also incorporated a rotor arm and condenser. In modern vehicles, it is replaced by a breakerless distributor and is usually called "electronic ignition system."

Breaker points:

A mechanical switch in the distributor with two metal contact points (usually made of silver, platinum, or tungsten) that open and close. When the points are closed, energy is stored in the primary windings of the coil. When the breaker points open, this energy is transferred to the secondary windings of the coil and stepped up, resulting in a high voltage to fire the plugs. The air gap between the breaker-point surfaces is critical. If the gap is too small, the timing is retarded, if too wide advanced. Also called points, contact points, and ignition points.
Also See:
dual breaker points
contact breaker point.

Breakerless:

A distributor or ignition system where the mechanical switching device (such as points or contacts) are replaced by an electronic switching device through the use of transistors. They are also called contactless or all-electronic ignitions.

Breaker strip:

Strip of wood or plastic used to cover joint between outside case and inside liner of refrigerator.

Breaker's yard:

A British term for a salvage yard.

Breaker-triggered transistorized ignition:

A transistorized ignition system whose distributor is the same as that of a coil ignition system, but whose contact breaker switches only the control current of the transistor, not the primary current. Usually not fitted as original equipment.

Breakeven:

In fusion, situation when the power produced exceeds the power input for heating and confinement.

Break in:

See:
break-in

Break-in:

Period of operation between the installation of new or rebuilt parts and the time in which the parts are worn to the correct fit, driving at a reduced and varying speed for a specified mileage to permit parts to wear to the correct fit. British term is "run-in."

Breaking capacity:

The capacity of a switch, circuit breaker, or other similar device to break an electric circuit under certain specified conditions.

Breaking piece:

An easily replaceable member of a machine subject to sudden overloads, made weaker than the remainder, so that in breaking it protects the machine from extensive damage.

Braking radiation:

See:
bremsstrahlung

Breaking stress:

The stress necessary to break a material, either in tension or compression.
Also See:
strength measures

Break-in oil:

Special formulated oil used in a new engine for a specified amount of time so that all bearing surfaces, etc. are properly seated.

Break jack:

See:
jack

Break one-oh:

Trucker slang for "I want to talk (on channel 10)" as in "Can I get a break one-oh."

Break-out box:

(BOB) A service tool that tees-in between the computer and the multi-pin harness connector. Once connected in series with the computer and the harness, this test device permits measurements of computer inputs and outputs.

Breakover:

The area of a dent in a panel where the sheet metal is actually buckled into the opposite direction of its normal shape.

Break time:

The length of time the contact breaker points remain open. Opposite to dwell

Break up:

British term for dismantling a vehicle and selling the parts. Similar to part out

Breakwater:

1. Plates fitted on a forward weather deck to form a V-shaped shield against water that is shipped over the bow.
2. A natural or artificial coastal barrier serving to break the force of the wave so as to provide safe harborage behind, it differs from the bulwark in that it has the sea on both sides of it.

Breakwater-glacis:

An inclined stone paving of piers and breakwaters, designed to take the force of impact of the waves.

Breasthook:

A triangular plate bracket joining port and starboard side stringers at the stem.

Breathalyze:

To administer a breathalyzer test.

Breathalyzer:

A device into which a driver blows to determine the amount of alcohol in his breath (and thus in his blood)

Breathalyzer test:

A test given by the police to determine if a driver has exceeded the allowable alcohol content in his system.

Breather:

A vent in the crankcase for relieving internal pressure or admitting air.
Also See:
crankcase breather
oil breather pipe
oil breather

Breather pipe:

A vent or pipe opening into the interior of the engine. It is used to assist ventilation the pipe usually extends downward to a point just below the engine so that the passing air stream will form a partial vacuum thus assisting in venting the engine.
Also See:
oil breather pipe

Breather port:

The small passage between the master cylinder fluid reservoir and the area behind the primary cups of the pistons. This port allows fluid from the reservoir to fill the area behind the cups when the brakes are applied, which prevents air bubbles from traveling around the lips of the primary cups as the brakes are released.
Also See:
replenishing port

Breathing:

The action of taking in air for combining with fuel for burning as energy and then exhausting it.
Also See:
breathing capacity

Breathing capacity:

The volume of air that enters the cylinder during each intake stroke. Volumetric efficiency is determined by comparing the actual volume of air with the maximum possible amount. Also called air capacity.

Breath test:

See:
breathalyzer test

Bredig's arc process:

A process for making colloidal suspensions of metals in a liquid by striking an arc in the liquid between two electrodes of the metal.

Breech block:

A movable block used for closing and opening an aperture, originally in guns but now also in machines.

Breeching:

Space in hot water or steam boilers between the end of the tubing and the jacket.

Breeder:

Fusion reactor in which further fuel (tritium) is bred from lithium blanket surrounding the fusion chamber.

Breeder reactor:

A fission reactor which produces more fissile material than is consumed in its operation. Fast reactors can be so designed.

Breeding ratio:

The number of fissionable atoms produced in fertile material per fissionable atom, destroyed in a nuclear reactor. Symbol b _r . The quantity b _r -1 is known as the breeding gain.

Bremsstrahlung:

Electromagnetic radiation emitted when a charged particle changes its velocity. Thus when electrons collide with a target and suffer large decelerations, the X-radiation emitted constitutes the continuous X-ray spectrum. From the German for braking radiation.

Brevet:

Literally, the word means "certificate," "patent," or "diploma" in French. In randonneuring, it means two things: certification of having successfully done a randonné, and the long-distance bicycle event itself of at least 200 kilometers. Brevet and randonnée are often interchangeable terms, but a randonnée might be considered to be less structured or less formal than a brevet.

Brewster:

A vehicle brand of which the 1925-1948 models with required application are classic cars.

BRG:

Acronym for British Racing Green

Bricklayer hammer:

A special hammer for chipping cement blocks and bricks.

Bridge:

1. A metal support which is installed in the valve slot of a wheel rim and prevents the flap and tube from bulging through the slot under high pressure and high heat conditions. Also called lemna.
2. Circuit often used for measurement of the impedance of passive components, for both ac and dc. Four arms of the bridge are arranged in a diamond-shaped configuration, three comprising accurately known impedances and the fourth, the unknown. A voltage supply is connected to two opposite corners of the diamond and a detector between the other two. By adjusting the known component values, the bridge is balanced when the detector shows a null signal and equations are then available for the unknown in terms of the other three arms of the bridge.
3. A structure spanning a river, road, etc. giving communication across it.

Also See:
arch bridge
bailey bridge
balance-bridge
bowstring bridge
flying bridge
house bridge
navigating bridge
port bridge

Bridge bearing:

Bearing on which the decks of bridges rest to accommodate esp. horizontal thermal expansion and contraction. Usually a steel plate on steel rollers or a laminated structure of steel plates sandwiching blocks of rubber. Also See:
expansion rollers
laminated bearing

Bridge bolts:

High-strength bolts used to fasten together the halves of a split brake caliper.

Bridge classification:

Bridge structures can be classified into five groups, each of which imposes loads on their materials in different ways.

Bridged:

See:
diode

Bridge Formula

A bridge protection formula used by federal and state governments to regulate the amount of weight that can be put on each of a vehicle's axles, and how far apart the axles (or groups of axles) must be to legally carry a given weight.

Bridge fuse:

A fuse in which the fusible wire is carried in a holder, supported by spring contacts at its two ends; it is thus easily removable for renewing the fuse wire.

Bridge gauge:

A measuring device for directing the relative movement of two parts of a machine due to wear at bearings, etc.

Bridge hanger:

A form of hanger of small vertical dimensions, for supporting the overhead contact-wire of a traction system under bridges or tunnels.

Bridge igniter:

A device for detonating the air bag.

Bridge-megger:

A portable instrument for measuring large resistances on the Wheatstone-bridge principle. A megger contains a source of emf and the instrument dial on which the balance is indicated.

Bridge oscillator:

Oscillator in which positive feedback and limitation of amplitude is determined by a bridge, which contains a quartz crystal for determining the frequency of oscillation. Devised by Meachan for high stability of operation in crystal clocks, etc.

Bridges and materials:

The dependence of the length of the span of a bridge on the strength of materials.

Bridge transition:

A method, employed in connection with the series-parallel control of traction motors, in which the change from series to parallel is effected without interrupting the main circuit, and without any change in the current flowing in each of the motors.

Bridge washer:

A protective thin metal washer installed at the valve stem between the flap and rim base to prevent the tube and flap from protruding through the valve slot as a result of high pressure and high temperature.

Bridging:

A characteristic of undercoats that occurs when a scratch or other imperfection in the surface isn't completely filled. Usually due to under-reducing the primer or using a solvent that dries too fast.
Also See:
gap bridging

Bridle:

A portion of an overhead contact-wire system. It extends longitudinally between supporting structures and is attached at intervals to the contact-wire, in order to retain the latter in its proper lateral position.

Bright:

A lustrous, shiny finish. Opposite to matt

Bright annealing:

The heating and slow cooling of steel or other alloys in a carefully controlled atmosphere, so that oxidation of the surface is reduced to a minimum and the metal surface retains its bright appearance.
Also See:
box annealing

Bright emitter:

A thermionic valve with a pure tungsten cathode, heated by a dc current to 2600K in order to emit electrons. Originally used on all thermionic valves; now superseded by treated cathodes which emit at much lower temperatures.

Brightener:

An addition agent added to an electroplating solution to produce bright deposits.

Brightening:

See:
anode brightening
chemical brightening

Brightness:

See:
luminance As a quantitative term, brightness is deprecated.

Brightness control:

Control which alters the brightness on a cathode-ray tube.

See:
automatic brightness control

Bright plating:

The production of a fairly bright deposit from an electroplating plant. Such surfaces require little finishing.

Brilliance:

The presence of considerable numbers of high harmonics in musical tone, or the enhancement of these in sound reproduction.

Brillouin formula:

A quantum mechanical analogue in paramagnetism of the Langevin equation in classical theory of magnetism.

Brillouin scattering:

The scattering of light by the acoustic modes of vibration in a crystal, i.e., photon-phonon scattering.

Brillouin zone:

Polyhedron in k-space, k being the position wavevector of the groups or bands of electron energy states in the band theory of solids. Often constructed by consideration of crystal lattices and their symmetries.

Brine:

Water saturated with a chemical such as salt.

See:
alcohol brine

Brinelled:

A type of wear in bearing components that is a series of dents in the races or cups

Brinell hardness:

A test of a metal's hardness by hydraulically pressing a hard ball into the metal.

Brinell hardness test:

A method of measuring the hardness of a material by measuring the area of indentation produced by a hard steel ball under standard conditions of loading. Expressed as either Brinell hardness number (BHN) or, preferably, B_H following the number, which is the quotient of the load on the ball in kilogram force divided by the area of indentation in square millimeters.

Bristol:

See:
Arnolt Bristol

Britannia metal:

Alloy series of tin (80-90%) with antimony, copper, lead, or zinc, or a mixture of these.

British Association:

(BA) A term used to describe a series of fine, small diameter threads for electrical and precision equipment.

British Association screw-thread:

(BA thread) A system of symmetrical vee threads of 47.5° included angle with rounded roots and crests. It is designated by numbers from 0-25, ranging from 6.0 to 0.25mm in diameter and from 1 to 0.07mm pitch. Used in instrument work, but now being superseded by standard metric sizes. Even numbers are preferred sizes.

British Leyland:

(BL) A former manufacturer of British automobiles, now called the Rover Group.

British Motor Corporation:

(BMC) A former manufacturer of British automobiles which changed its name to British Leyland and then to the Rover Group.

British Racing Green:

(BRC) A dark green color which used to be the official racing color for British cars.

British Standard brass thread:

A screw-thread of Whitworth profile used for thin-walled tubing. It has 26 threads per inch for each diameter.
Also See:
British Standard Whitworth thread

British Standard Fine:

(BSF) The fine screw thread used on most British vehicles before metrication. The coarse thread was British Standard Whitworth

British Standard pipe thread:

(BSP thread) A screw-thread of Whitworth profile, but designated by the bore of the pipe on which it is cut (e.g., 3/8 in gas) and not by the full diameter, which is a decimal one, slightly smaller than that of the pipe. Also called British Standard Whitworth thread.

British Standards Institution:

(BSI) An organization which prepares and issues British standard specifications.

British Standard specification:

(BSS) A specification of efficiency, grade, size, etc., drawn up by the British Standards Institution, referenced so that the material required can be briefly described in a bill or schedule of quantities. The definitions are legally acceptable.

British Standard Whitworth:

(BSW) A coarse screw thread used on British vehicles before metrication. It has a profile angle of 55° and a radius at root and crest of 0.1373 x pitch; 1/6 of the thread cut-off. The pitch is standardized with respect to the diameter of the bar on which it is cut.

British Standard Wire Gauge:

See"
Standard Wire Gauge

British thermal unit:

(BTU) A measurement of the amount of heat required to raise the temperature of one pound of water, one degree Fahrenheit (usually taken as 60° to 61°F). Equivalent to 252 calories, 778.2 ft-lbf, 1055J. 10⁵ Btu=1 therm.

Brittle fracture:

Fracture which occurs with no discernable plastic deformation, i.e., in the elastic region of the stress-strain curve. Caused by propagation of a crack as distinct from yielding. In metals it may be either intergranular or by cleavage along certain crystal planes.
Also See:
strength measures

Brittleness:

The tendency to brittle fracture, i.e., without significant plastic deformation. Loosely used as the opposite of toughness, but more precisely means having low values of toughness or fracture toughness.
Also See:
acid brittleness
blue brittleness
strength measures

Brittle point:

A low extreme temperature at which a substance (like rubber) fractures on sudden impact.

Brittle temperature:

Point at which a material changes in fracture behavior, from ductile to brittle. For polymers, it is often a little below T_g. Sometimes denoted T_B. Sensitive to sample geometry (e.g., stress concentrations) and rate effects, such as occur in impact tests.

Broach:

1. Bringing a metal surface to the desired shape by forcing (pushing or pulling) a multiple-edged cutting tool across the surface.
2. A metal cutting tool for machining holes, often non-circular; it consists of a tapered shaft carrying transverse cutting edges, which is driven or pulled through the roughly finished hole.

Broad-base tower:

A transmission line tower with each leg separately anchored.

Broad gauge:

A railway gauge in excess of the standard 4 ft 8½ in (1.435 m). In particular, the gauge of 7 ft (2.134 m) laid down by Brunel but also the standard gauges of e.g., India, Russia, and Spain.

Broglie wavelength:

See:
de Broglie wavelength

Broken-in:

A condition in which a new engine has overcome any wear-in problems.

Broken storage:

The spaces between and around cargo packages, including dunnage, and spaces not usable because of structural interference.

Broker:

An intermediary with legal authority to operate on behalf of the manufacturer.

Bronze:

An alloy of copper and tin; but now applied to other alloys not containing tin, e.g., aluminum bronze, manganese bronze, and beryllium bronze.
Also See:
alpha bronze
aluminum bronze
beryllium bronze
copper alloys
phosphor-bronze
sintered bronze

Bronze welding:

See:
braze welding

Brough:

A vehicle brand of which the 1925-1948 Superior with required application are classic cars.

Brougham:

See:
Cadillac Eldorado Brougham

Brow:

A small inclined ramp to allow passage of trucks over a hatch coaming or bulkhead door sills etc.

Brown and Sharpe wire gauge:

(B and S wire gauge) A system of designating the diameter of wire by numbers; it ranges from 0000 (0.46 in) to 50 (0.001 in).
Also See:
American Standard Wire Gauge

Brownian movement:

Small movements of bodies such as particles in a colloid, due to statistical fluctuations in the bombardment by surrounding molecules of the dispersion medium. It may be directed by movement of a galvanometer coil. Also called Brownian motion and colloidal movement and pedesis.
Also See:
colloidal state

Bruise:

Any tire injury which weakens, breaks, or separates the carcass cords without damaging the visible rubber surface.

Brush:

1. A paintbrush.
   Also See:
   airbrush
   
2. The pieces of carbon, graphite, or copper, that rub against the commutator on the generator or starter motor or against the slip rings on an alternator and conducts current from the power supply to the armature windings. As they wear down, they need to be replaced.
3. A rubbing contact on a commutator, switch, or relay. Also called wiper.

Also See:
battery brush
carbon brush
card brush
cup-shaped wire brush
file card brush
spark plug brush
third brush
wire brush

Brush-box:

That portion of the brush-holder of an electrical machine in which the brush slides or in which it is clamped.

Brush contact:

See:
laminated contact

Brush curve:

The voltage drop between the brush arm and the segment beneath the brush at points along the brush width plotted against brush width as an indication of the correctness of compole flux density in a dc machine.

Brush discharge:

Discharge from a conductor when the potential difference between it and its surroundings exceeds a certain value but is not enough to cause a spark or an arc. It is usually accompanied by hissing high noise. Also called brushing discharge and corona.

Brushes:

See:
brush

Brush gear:

A general term used to denote all the equipment associated with brushes of a commutating or slip-ring machine.

Brush holder:

A device which keeps the carbon brushes in an electric motor in contact with the commutator or slip ring.
Also See:
brush-box
box-type brush-holder

Brush-holder arm:

The rod or arm supporting one or more brush holders. Also called brush spindle or brush stud.

Brushing discharge:

See:
brush discharge

Brush lead:

See:
brush shift

Brush plating:

Method in which the anode carries a pad or brush containing concentrated electrolyte or gel which is worked over the surface to be plated. Similar methods are used for brush polishing

Brush rocker:

A support for the brushes of an electrical machine which enables them to be moved bodily around the commutator.

Brush-rocker ring:

See:
brush rocker

Brush shift:

The amount by which the brushes of a commutating machine are moved from the center of the neutral zone. Also called brush lead.
Also See:
backward shift
forward shift

Brush spindle:

See:
brush-holder arm

Brush spring:

A spring which pushes against the back end of a carbon brush in an electric motor to force it against the commutator or slip ring.
Also See:
carbon brush spring

Brush stud:

See:
brush-holder arm

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