A pallet jack, also known as a pallet truck, pump truck, or jigger is a tool used to lift and move 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...

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The front wheels are mounted inside the end of the forks, and as the hydraulic jack is raised, the forks are separated vertically from the front wheels, forcing the load upward until it clears the floor. The pallet is only lifted enough to clear the floor for subsequent travel.

Powered pallet jack

Powered pallet jacks, also known as electric pallet trucks, walkies, single or double pallet jacks, are motorized to allow lifting and moving of heavier and stacked pallets. These generally contain a platform for the user to stand while hauling pallets around a warehouse or loading/unloading trucks. The powered pallet jack is generally moved by a throttle on the handle to move forward or in reverse and steered by swinging the handle in the intended direction. Some contain a type of dead man's switch

Dead man's switch

A dead man's switch is a switch that is automatically operated in case the human operator becomes incapacitated, such as through death or loss of consciousness....

 rather than a brake to stop the machine should the user need to stop quickly or leave the machine while it is in use. Others use a system known as ``plugging`` where in the driver turns the throttle from forward to reverse (or vice-versa) to slow and stop the machine, as the dead man's switch is used in emergencies only.

Operational limitations

• Reversible pallets cannot be used.
• Double-faced nonreversible pallets cannot have deckboards where the front wheels extend to the floor.
• Enables only two-way entry into a four-way notched-stringer pallet, because the forks cannot be inserted into the notches.

Typical Dimensions

The North American industry seems to have 'standardized' pallet jacks in several ways:

• Width of each of two Forks: 7"
• Fork Width, i.e. The dimension between the outer edges of the forks: Available as 20¼" and 27"
• Fork Length: Available as 36", 42", 48"* Lowered Height: 2.9"
• Raised Height: At least 7.5", but some will raise higher

External links

• OSHA hazards of working with pallet jacks
• Pallet jack history -- This New Truck Gets Under the Load and Lifts It, Popular Science
  Popular Science
  Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...
  
  monthly, December 1918, page 54, Scanned by Google Books: http://books.google.com/books?id=EikDAAAAMBAJ&pg=PA54