Wheel chocks (or chocks) are wedges of sturdy material placed closely against a vehicle's
wheel
A wheel is a circular component that is intended to rotate on an axle bearing. The wheel is one of the key components of the wheel and axle which is one of the six simple machines. Wheels, in conjunction with axles, allow heavy objects to be ...
s to prevent accidental movement. Chocks are placed for safety in addition to setting the
brakes
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction.
Backgroun ...
. The bottom surface is sometimes coated in rubber to enhance grip with the ground. For ease of removal, a
rope
A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similarl ...
may be tied to the chock or a set of two chocks. One edge of the wedge has a concave profile to contour to the wheel and increase the force necessary to overrun the chock. Most commonly, chocks are seen on
aircraft
An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or by using the Lift (force), dynamic lift of an airfoil, or in ...
and train cars.
Automobiles usually have
parking brake
In road vehicles, the parking brake, also known as a handbrake or emergency brake (e-brake), is a mechanism used to keep the vehicle securely motionless when parked. Parking brakes often consist of a cable connected to two wheel brakes, which i ...
s on the rear wheels. If the rear axle is jacked off the ground with only the parking brake set, the vehicle may roll on the front wheels and fall. Chocking the front wheels prevents this mishap.
Motorcycle and bicycle chocks are bifurcated and fit around the wheel, supporting the bike and preventing its movement.
The mining industry uses wheel chocks to protect lubrication trucks and heavy maintenance vehicles from slipping on off-road terrain when placed in Park. The huge haul trucks, which can weigh up to 450 tonnes, require a much larger wheel chock that itself will weigh almost 40 kilograms. These circumstances will benefit from urethane wheel chocks that are lightweight enough to be maneuvered, yet can withstand the responsibility of holding a truck if a brake should fail. The Mine Safety and Health Administration (MSHA) has established standards that wheel chocks are used when a vehicle is parked on a grade, and OSHA has guidelines that require wheel chocks during loading or unloading of a heavy truck.
Parking chocks
A
parking space
A parking space, parking place or parking spot is a location that is designated for parking, either paved or unpaved. It can be in a parking garage, in a parking lot or on a city street. The space may be delineated by road surface markings. ...
commonly contains a parking chock (also known as a parking curb, parking bumper, wheel stop, parking chock, curb stop, bumper block,
and turtarrier), a barrier which is used to prevent cars from pulling too far into the space and obstructing an adjacent parking space, curb, or sidewalk.
This barrier is usually made of
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...
or recycled plastic and will normally be a horizontal bar to prevent the tires from moving forward or a vertical bar that may cause damage to the vehicle if contact is made. In a parking garage, the barrier will often be a concrete wall. The recycled plastic parking stops are lighter weight than concrete and will not crack or chip. This lighter version can be installed by one person and will resist auto oils and fuels and will never need maintenance such as repainting.
Gallery
File:Un cal pour voiture.jpg, Wheel chock placed under a car's wheel.
File:Airbus A321-231 - British Airways - G-EUXH - EHAM (2).jpg, Chocks being fitted to a British Airways
British Airways (BA) is the flag carrier airline of the United Kingdom. It is headquartered in London, England, near its main hub at Heathrow Airport.
The airline is the second largest UK-based carrier, based on fleet size and passengers ...
Airbus A321
The Airbus A321 is a member of the Airbus A320 family of short to medium range, narrow-body, commercial passenger twin engine jet airliners; it carries 185 to 236 passengers. It has a stretched fuselage which was the first derivative of the b ...
.
Image:F-117 Nighthawk fighter during an end of runway check.jpg, An airman
An airman is a member of an air force or air arm of a nation's armed forces. In certain air forces, it can also refer to a specific enlisted rank. An airman can also be referred as a soldier in other definitions.
In civilian aviation usage, t ...
prepares to pull the landing gear wheel chock of an F-117 Nighthawk
The Lockheed F-117 Nighthawk is a retired American single-seat, twin-engine stealth attack aircraft developed by Lockheed's secretive Skunk Works division and operated by the United States Air Force (USAF). It was the first operational aircr ...
attack aircraft during an end of runway check at Kunsan Air Base
Kunsan K-8 Air Base is a United States Air Force base located at Gunsan Airport, on the west coast of the South Korean peninsula bordered by the Yellow Sea. It is located in the town of Gunsan (also romanized as Kunsan), about south of Seoul.
...
, South Korea.
See also
*
Chocks
*
Railway wheel stop
References
External links
* {{Commonscat-inline, Wheel chocks
Aviation ground support equipment
Tools