Gravity Flow Rack

Overview

A gravity flow rack stores cartons on sloped roller or skate-wheel lanes so that gravity moves each carton from the rear load aisle toward the front pick face. As a picker removes the lead carton, the next carton rolls forward to take its place. Because cartons are loaded at the back and picked from the front, stock rotates first in, first out, which suits dated and lot-controlled goods. The format concentrates many SKUs into a compact pick face and keeps the next carton always presented, so it is a mainstay of order-picking and kitting areas.

Compared with static shelving, flow rack roughly doubles the SKUs reachable from a single pick position and removes the walking and reaching needed to find the next carton. Compared with pallet flow, it works at the carton and tote scale rather than full pallets, feeding hand-pick operations rather than fork trucks.

Frame and Structure

The load is carried by the Upright Frame assemblies. Each frame is two roll-formed Upright Post uprights joined by Frame Brace members, standing on Base Plate plates with levelling Levelling Foot Pad feet. The posts carry a slotted pattern so lane brackets can hook in at any height, letting the rack be reconfigured as the SKU mix changes.

Frames are tied together by the Bracing Set set. Horizontal ties and diagonal braces square the structure and resist the sway loads that come from cartons rolling and being pulled off the pick face. The whole rack is fixed to the slab by the Floor Anchor Set, with an anchor at every base plate, because the pick-face pull and replenishment push both tend to walk an unanchored rack forward over time.

Flow Lanes

Each Sloped Lane Bed is a single carton lane pitched 3 to 7 degrees toward the front. Light cartons run on a Skate-Wheel Track of many small wheels, which spreads the carton weight and tolerates soft or irregular box bottoms. Heavier or wider cartons run on full-width Lane Roller units instead. A Lane Divider keeps cartons in line, and a flared Entry Guide funnels each carton into the lane at the load end.

The slope is set by the Flow Step-Down Bracket step-down brackets. Each Bracket Slope Arm hooks into the slotted post and drops the front of the lane below the rear, with a Slope Shim for fine pitch adjustment and a Bracket Safety Clip locking it to the post. Getting the slope right is the central design problem of a flow rack. Too shallow and light cartons stall partway down; too steep and heavy cartons reach the face too fast and slam the stop.

Speed Control

Because carton weight varies, slope alone cannot hold a safe and consistent face speed. The Brake Roller solves this. A Brake Element inside the Brake Roller Tube applies centrifugal or viscous drag that rises with speed, so a heavy fast carton is braked hard while a light slow one is barely touched. Brake rollers are placed near the front of deeper lanes to hold the lead carton to roughly 0.3 to 0.5 m/s as it reaches the pick face. Each roller turns on its Ball Bearing sets and is held by a Brake Roller Axle.

Pick Face

The Pick Face is where the operator works. A Front Stop holds the lead carton at the pick line so it does not roll off the rack. A Carton Separator lifts or eases the lead carton slightly so it can be drawn off without the queue behind shoving it. A Lane Label Holder presents the SKU and location label, and Pick Front Guide rails square the carton to the picker. A well-set pick face presents a clean, square carton at a comfortable height with the label readable, which is what keeps pick rates high.

Materials, Variants and Use

Posts and beams are roll-formed steel, powder coated or galvanized. Lanes use plated steel or impact-resistant plastic wheels. Variants include carton flow built into the lower levels of a pallet rack with bulk storage above, full mobile flow benches for kitting, and pick-to-light flow where each lane carries a display and confirm button.

Gravity flow rack is chosen for order picking of small and medium cartons, for kitting lines that need many components presented at one station, and for buffering fast movers ahead of packing. It earns its place where pick density and stock rotation matter more than the simple flexibility of static shelving, and where the product is too small or too light to justify pallet-scale flow.