Pallet Flow Rack

Overview

A pallet flow rack stores full pallets on deep, inclined roller lanes so that each loaded pallet rolls forward under its own weight from the rear load aisle to the front pick aisle. A fork truck pushes a pallet onto the back of a lane, the pallets ahead of it index forward, and the lead pallet is drawn out at the front. Because loading and picking happen at opposite ends, stock rotates first in, first out, which is the reason pallet flow is chosen for dated food, beverage and pharmaceutical stock. Lanes can run from a few pallets deep to twenty or more, packing dense storage while keeping every lane a separate selective face at the front.

Pallet flow trades the random access of selective racking for far higher density and automatic stock rotation. It differs from drive-in racking, which is also deep but loads and unloads from the same aisle and rotates last in, first out. It scales the gravity-lane idea of carton flow up to full pallets weighing 300 to 1500 kg, which changes almost every engineering choice in the structure.

Frame and Structure

The deep lane loads are carried by the Upright Frame assemblies. Each frame uses heavy Upright Post uprights joined by Frame Brace members on welded Base Plate plates. Aisle-end posts carry a Column Guard because a fork truck pushing pallets onto a lane is the most common cause of frame damage. The Load & Pick Beam assemblies span between frames at the load and pick ends, carrying the lane ends through Beam Connector joints locked by a Beam Safety Pin.

Frames are tied by the Bracing Set set and fixed to the slab by the Floor Anchor Set. Anchoring is critical here. A deep lane of loaded pallets stores a large amount of energy, and the dynamic loads of pallets indexing forward and of fork trucks pushing at the rear would walk an unanchored structure. Every frame is anchored, with heavier fixings than carton flow needs.

Roller Lanes

Each Inclined Roller Lane is a pallet-wide bed of heavy Gravity Roller units carried on Roller Side Rail side rails, pitched at about 4 percent. The slope is shallow compared with carton flow because the pallets are heavy and the goal is a slow, controlled creep rather than a free roll. A Lane Guide Rail centres each pallet, and a replaceable Wear Strip takes the abrasion at the pallet contact edges. The rollers turn on sealed Ball Bearing sets sized for the repeated heavy point loads.

Speed Control

A loaded pallet on a 4 percent slope would accelerate to a dangerous speed over a long lane, so the Speed Controller governs flow. Centrifugal Brake Roller units are spaced down the lane, each holding a Brake Element that applies drag rising sharply with speed. The result is a near-constant creep of about 0.2 m/s regardless of how heavy the pallet is or how many pallets are queued behind it. Spacing the brakes down the full lane, rather than only at the front, keeps the whole queue moving smoothly and stops pallets from gapping and then slamming together.

Separation at the Pick Face

When the lead pallet is removed, the weight of the queue behind it must not slam the next pallet against the picker or the truck forks. The Pallet Separator handles this. A Separator Arm holds the second pallet back while the lead pallet is drawn out, and a Separator Cam tied through the Separator Linkage releases it to index forward only after the lead pallet has cleared. The Coil Spring returns the mechanism. This staged release is what makes deep pallet flow safe to pick by hand or by truck.

Loading and Entry

At the rear, the Entry Stop & Guide assembly squares each pallet as it is loaded. A Load Back Stop sets the load datum, Entry Flare Guide guides funnel a slightly misaligned pallet into the lane, and a Load End Bumper absorbs the push of the fork truck. Good entry geometry matters because a pallet pushed in crooked can jam a deep lane that is hard to clear.

Materials, Variants and Use

Posts, beams and rails are structural or heavy roll-formed steel, powder coated or galvanized. Rollers are steel for the heaviest loads. Variants include full-depth flow for buffer storage, shallow two to four pallet flow built into pick modules, and carton-and-pallet hybrid bays with carton flow below and pallet flow above.

Pallet flow rack is chosen where high pallet throughput and strict stock rotation matter together, such as beverage and food distribution, cold storage staging, and manufacturing line-side buffers. It earns its place where the density of deep storage is needed but last in, first out rotation would be unacceptable.