Push-Back Racking
DistribuTek Leaning Center
With a rail-guided carrier provided for each pallet load, push back rack provides last-in-first-out deep lane storage. It gets its name from the manner in which it
operates,
where loads are placed on telescoping carts on inclined rails, which are
then pushed back into the rack with subsequent l oads. Push back rack
uses a common entrance and exit (the forklift loads and recovers from the same position),
requiring only one aisle for proper operation. Each storage lane has its own set
of carts, so they operate independently, increasing the selectivity of push back
as opposed to a drive-in system of the same depth. Depending upon the depth of the
push back lane, measured in pallet positions, there are a number of carts riding
a pair of rails, one pair of rails per lane. Since the last load inserted rests
on the cart rails as noted below, the number of carts is the number of positions
deep minus one. The first load inserted is placed upon the top cart of the telescoped
group. When the next load is inserted, the lift truck driver pushes the top cart
and its load back to expose the next cart, upon which the second load is set. This sequence is repeated until, when the loads are all pushed back, only the set of
rails upon which the carts ride is exposed. The last load is placed directly upon
the rails. Unloading is done in reverse order, and because the loads are to flow
toward the front of the lane, the lift truck driver must control the removal speed
to keep subsequent loads from -flowing to the front of the system. The increase
in selectivity and the potential for higher system utilization in comparison to
drive-in makes push back a logical choice for most operations, especially for those
requiring high throughput. Complexity and user needs normally limit push back to
2-5 positions deep.
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