Pallet jack

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Typical manual pallet jack (lowered)

A pallet jack, also known as a pallet truck,[1] pallet pump, pump truck,[1] or jigger[1] is a tool used to lift and move pallets.

Operational principle[edit]

The jack is steered by a 'tiller' like lever that also acts as the pump handle for raising the jack. A small handle on the tiller releases the hydraulic fluid, causing the forks to lower. The front wheels inside the end of the forks are mounted on levers attached to linkages that go to levers attached to the jack cylinder. As the hydraulic jack at the 'tiller' end is raised, the links force the wheels down, raising the forks vertically above the front wheels, raising the load upward until it clears the floor. The pallet is only lifted enough to clear the floor for subsequent travel. Oftentimes, pallet jacks are used to move and organize pallets inside a trailer, especially when there is no forklift access or availability.

Operating mechanism
Pallet jack in lowered position, allowing it to be inserted under a load on a pallet
 
Jack showing how wheels drop, lifting forks and load. The steering tiller and raised hydraulic cylinder are clearly visible on the right
 
Underside of a jack showing linkages under forks
 

History[edit]

Manual pallet jacks have existed since at least 1918.[2] Early types lifted the forks and load only by mechanical linkages. More modern type uses a hand pumped hydraulic jack to lift.

Types[edit]

Manual pallet jack[edit]

A manual pallet jack is a hand-powered jack.

Powered pallet jack[edit]

An electric pallet jack. The recharging lead can be seen.

Powered pallet jacks, also known as electric pallet trucks, walkies, single or double pallet jacks, or power jack, are motorized to allow lifting and moving of heavier and stacked pallets. Some contain a platform for the user to stand while moving pallets. 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 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[edit]

  • Reversible pallets cannot be used.
  • Double-faced non-reversible pallets cannot have deck-boards 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[edit]

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" (51.4 cm) and 27" (68.6 cm)[3]
  • Fork Length: Available as 36" (91.4 cm), 42" (106.7 cm), 48" (122 cm)[3]
  • Lowered Height: 2.9" (7.5 cm)[3]
  • Raised Height: At least 7.5" (19.1),[3] but some will raise higher

In Eurasia the overall dimensions are similar, as modern container palletization has forced standardization in the dimensional domain globally.

See also[edit]

References[edit]

  1. ^ a b c "PALLET JACKS, KNOWN AS A PALLET TRUCKS". Task Forklifts. Retrieved 31 August 2014. 
  2. ^ "This New Truck Gets Under The Load And Lifts It" (Scan by Google Books). Popular Science Monthly (Modern Publishing Company (Bonnier Corporation)). Vol.93 (Iss.6): p.54. December 1918. ISSN 0161-7370. Retrieved 31 August 2014. 
  3. ^ a b c d "Standard 2.9” Pallet Jack". U.S. Global Resources (USGR). Retrieved 31 August 2014. 

External links[edit]