Conveyor Sorter

Overview

A conveyor sorter is the machine that turns a stream of mixed parcels into sorted batches by destination. Cartons drop onto an induction conveyor, pass single-file through a barcode scan tunnel that reads each label, and are then pushed off the main line onto the chute matching their destination. The version described here is a sliding-shoe sorter, the workhorse of e-commerce and parcel hubs: it handles a wide weight and size range gently, runs at up to 6000 cartons an hour, and reads better than 99.5% of labels on the fly.

The whole machine is built on a bolted Conveyor Frame of structural steel on adjustable legs, so a line can be laid out to fit a building and re-pitched later. Parcels travel over a chain of Belt Conveyor Section and Roller Conveyor Section zones, each independently driven, and field devices land in a central PLC Control Cabinet that ties scanning to diverting.

How it works

Each Belt Conveyor Section is a self-contained zone: an endless belt runs over a lagged drive pulley turned by a geared induction Conveyor Drive Motor, tensioned against an idler tail pulley and carried on support rollers. Driven Roller Conveyor Section zones do the same job where a flat surface is not required, transmitting power between rollers with a shared belt. Every zone motor has its own Variable-Frequency Drive in the Motor Controller Bank, so the PLC can run zone-accumulation logic, slowing and gapping parcels so they arrive at the diverts one at a time.

The label is read by the Scan Station, a tunnel of imaging heads that captures the barcode from several sides as the parcel passes, while a light grid measures its height. The decoded barcode is handed to the PLC CPU Module, which already knows the parcel's position from the upstream photo-eyes, so it can schedule the exact divert.

Sortation happens at each Sliding-Shoe Divert. An array of shoes rides the moving slats; when a tracked parcel reaches the divert, a servo Divert Actuator steers a guide rail that sweeps the shoes diagonally across the belt, pushing the carton smoothly onto its take-away chute without stopping the line. The operator watches throughput and clears jams from the Operator HMI.