Pop-Up Wheel Sorter

Overview

A pop-up wheel sorter is a powered conveyor section that diverts cartons, totes and polybags onto branch lanes by raising banks of angled wheels through the carrying surface. When a wheel bank is flush with the bed, product passes straight over it on the carry rollers. When the Pop-Up Wheel Bank is raised, the skewed wheels contact the underside of the product and push it sideways onto a takeaway lane while it is still moving forward. The result is a smooth, low-impact divert that handles a wide product mix at sustained rates of 60 to 120 cartons per minute per lane.

These sorters sit in the middle band of sortation technology. They are gentler and quieter than pushers or paddle diverters, cheaper than shoe sorters or cross-belt loops, and they handle a broader range of product than a simple roller diverter. A typical installation has several divert banks along a single carry line, each feeding a shipping lane, a packing station or a returns chute.

Carrying Surface and Divert Banks

The Carry Conveyor Bed carries product across the machine on 50 mm rollers driven from below. Between the rollers sit the wheel cassettes. Each Divert Wheel is fitted with a polyurethane tyre and set at the divert angle, commonly 22 degrees for gentle merges or up to 45 degrees for tight branch spacing. Rows of wheels are linked by an O-ring drive so the whole Cassette Frame turns as a unit, with the Side Guide Rail keeping product square before it reaches the divert window.

The carry rollers turn continuously. The divert wheels also turn continuously when raised, so there is no acceleration shock at the moment of divert. The product is simply lifted a few millimetres onto the spinning angled wheels and carried off at a vector that combines the carry speed and the wheel speed. Keeping both surfaces moving is what lets the machine divert heavy cartons without scuffing labels or tipping tall product.

Lift Mechanism and Pneumatics

Each cassette is raised by the Lift Mechanism. An air bellows inflates against a pivot link, lifting the cassette 8 to 15 mm in 40 to 80 ms. When the controller exhausts the bellows, the Cassette Return Spring pulls the cassette flush with the bed again. Fast lift and settle times set the minimum gap the machine needs between cartons, so the actuator is sized for speed rather than force.

The Pneumatic Supply supply clean, dry air at 6 bar through a Filter-Regulator Unit. A Solenoid Valve Manifold holds one fast solenoid per bank, and local reservoirs buffer the air draw during sort bursts so that supply pressure does not sag when several banks fire in quick succession. A Pressure Sensor reports supply pressure back to the controller, which flags a fault if pressure drops below the level needed for reliable lift timing.

Drive System

The Drive System separates carry drive from divert drive. A Carry Gearmotor of 1.5 to 3 kW turns the carry rollers through a Gearbox Housing and poly-V belting. A separate Servo Motor or gearmotor drives the Divert Line Shaft, which distributes torque to every wheel cassette through timing belts. Splitting the drives lets the divert speed be tuned for product handling independently of line speed, and lets the carry line keep running while individual banks are serviced.

Controls, Tracking and Scanning

The Control System are built around a PLC that tracks each carton from the moment it is read until it reaches its assigned bank. A Belt Position Encoder on the carry shaft gives the controller a continuous position reference, so the PLC knows where every tracked carton is to within a few millimetres. When a carton reaches its divert window, the matching solenoid fires and the bank lifts.

The Scanner & Sensing Array reads each carton on entry. Top and side Barcode Imager units capture the routing barcode regardless of label orientation, while Photo-Eye Sensor sensors confirm gaps and presence. A Dimensioning Light Curtain measures carton width so the controller can size the divert window and avoid clipping a wide carton against the lane wall. A Bare PCB with an Microcontroller handles the high-speed sensor interface and passes tracking events to the PLC.

Structure and Variants

The Structural Frame is a welded and bolted steel structure on adjustable legs, with Sheet Metal Panel guarding over the drives. Frame height is set to match the upstream and downstream conveyors, and the legs are levelled so the bed stays flat across its width.

Variants cover left-hand, right-hand and dual-sided diverts from a single carry line. Narrow-pitch versions place banks closer together for dense lane fans, while heavy-duty versions use wider wheels and stronger bellows for cartons up to 35 kg. Common uses include order fulfilment shipping sortation, parcel induction to chutes, returns processing, and routing to multiple packing stations from one feed line. Because the divert is gentle and the carry line never stops, the machine suits operations that mix small polybags with large cartons on the same run.