A loading dock is a recessed bay in a building or facility where truck

Truck

A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile...

s are loaded and unloaded. They are commonly found on commercial and industrial buildings, and warehouse

Warehouse

A warehouse is a commercial building for storage of goods. Warehouses are used by manufacturers, importers, exporters, wholesalers, transport businesses, customs, etc. They are usually large plain buildings in industrial areas of cities and towns. They usually have loading docks to load and unload...

s in particular.

Loading docks may be exterior, flush with the building envelope

Building envelope

The building envelope is the physical separator between the interior and the exterior environments of a building. Another emerging term is "Building Enclosure". It serves as the outer shell to help maintain the indoor environment and facilitate its climate control...

, or fully enclosed. They are part of a facility's service or utility infrastructure, typically providing direct access to staging area

Staging area

A staging area is a location where organisms, people, vehicles, equipment or material are assembled before use.- In construction :...

s, storage rooms, and freight elevators.

Basics

In order to facilitate material handling, loading docks may be equipped with the following:

• Bumpers - protect the dock from truck damage, may also be used as a guide by the truck driver when backing up.
• Dock leveler - a height-adjustable platform used as a bridge between dock and truck
  Dock plate
  In a loading dock, one problem to overcome is the problem of bridging the gap between a truck and the dock or warehouse floor. Not all trucks are the same height, and the height of the trailer floor within a truck can vary according to how heavily the truck is laden. Thus there is not only a gap...
  
  , can be operated via mechanical (spring
  Spring (device)
  A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...
  
  ), hydraulic
  Hydraulics
  Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control,...
  
  , or air powered
  Pneumatics
  Pneumatics is a branch of technology, which deals with the study and application of use of pressurized gas to effect mechanical motion.Pneumatic systems are extensively used in industry, where factories are commonly plumbed with compressed air or compressed inert gases...
  
   systems.
• Dock lift - serves same function as a leveler but operates similar to a scissor lift to allow for greater height adjustments.
• Dock seals - compressible foam blocks against which the truck presses when parked; seals are used at exterior truck bays in colder climates where this will provide protection from the weather.
• Truck or vehicle restraint system - a strong metal hook mounted to the base of the dock which will hook to the frame or bumper of a trailer and prevents it from rolling away during loading operations, can be operated via manual, hydraulic, or electrical systems; this system can replace or work in conjunction with wheel chocks
  Chock (wheel)
  Wheel chocks are wedges of sturdy material placed behind a vehicle's wheels to prevent accidental movement. Chocks are placed for safety in addition to setting the brakes. The bottom surface is sometimes coated in rubber to enhance grip with the ground. For ease of removal, a rope may be tied...
  
  .
• Dock light - a movable articulating light mounted inside the dock used to provide lighting inside the truck during loading operations.
• Loading Dock Software - provides a method for tracking and reporting on the loading dock activity.

Warehouses that handle pallet

Pallet

A pallet , sometimes called a skid, is a flat transport structure that supports goods in a stable fashion while being lifted by a forklift, pallet jack, front loader or other jacking device. A pallet is the structural foundation of a unit load which allows handling and storage efficiencies...

ized freight use a dock leveler, so items can be easily loaded and unloaded using power moving equipment (e.g. a forklift). When a truck backs into such a loading dock, the bumpers on the loading dock and the bumpers on the trailer come into contact and create a gap; also, the warehouse floor and the trailer deck may not be horizontally aligned. The most common dock height is 48” – 52”, though heights of up to 55" occur as well. A dock leveler bridges the gap between a truck and a warehouse to accommodate a forklift.

Where it is not practical to install permanent concrete loading docks, or for temporary situations, then it is common to use a mobile version of the loading dock often called a yard ramp

Yard ramp

A yardramp, sometimes called mobile yardramp or container ramp, is a movable metal ramp for loading and unloading of shipping containers and vehicle trailers, without the need for permanent docking bays...

.

Dangers

There can be very serious accidents on loading bays. One example is trailer creep (also known as trailer walk, or dock walk) which occurs when the lateral and vertical forces exerted each time a forklift truck enters and exits the trailer cause the trailer to slowly move away from the dock resulting in separation from the dock leveler. Factors that affect trailer creep are the weight and speed of the lift truck and load, the gradient of the ground the trailer is parked on, the condition of the suspension and the air pressures, the type of transition (dock levelers, dock boards) being used, and whether the trailer has been disconnected or if it is still connected to the tractor.

Separation of a vehicle from the loading also occurs when a driver prematurely pulls away while the truck is still being loaded/unloaded. This issue is usually caused through a driver not correctly observing traffic lighting signals on a loading bay which prohibit the movement of the trailer. Also, it is important to ensure drivers are fully trained with regard the Safe System of Work he/she is expected to follow.

Major manufacturers & Distributors

1. Dynamic Loading http://www.dynamicloading.com
2. Butt http://www.butt.de
3. Rite Hite Ramps http://www.ritehite.com
4. Beacon Technology http://www.beacontechnology.com