Tilt-Tray Sorter

Overview

A tilt-tray sorter is a high-speed sortation machine that carries each parcel on its own small tray around a closed loop and tips that tray sideways at the right point to drop the parcel into a destination chute. Because every parcel rides a dedicated tray and the tray can tip either way, the machine sorts a wide mix of shapes and sizes to hundreds of destinations at thousands of items an hour. It is the workhorse of parcel hubs, postal sorting centres, and large e-commerce fulfilment buildings, where a flood of mixed parcels has to be split to delivery routes, stores, or order bins quickly and accurately.

The sorter is built from a Track Loop that the trays circulate on, a Tray Carriers of tray carts, a Tilt Mechanism on each cart, a Linear Induction Drive that propels the loop, the Induction Stations stations that load parcels on, the Discharge Chutes that catch them, and a Sortation Control that ties it all together.

The loop and carrier train

The Track Loop is a closed circuit of Rail Section running rail and banked Curve Section curves, held at working height on Support Leg legs. Around it runs the Tray Carriers, a continuous chain of Carrier Cart carts joined by Cart Coupling couplings so they move as one. Each cart rides on polyurethane-treaded Running Wheel wheels on Ball Bearing bearings, kept centred by Guide Wheel guide wheels, and its cast Cart Frame carries a single Tray. The trays run nose to tail so the loop is effectively a moving shelf of addressable trays.

How a tray tips

The sort happens at the Tilt Mechanism. Each tray sits on a Tray Pivot so it can rock left or right, and it is held level by a Tray Latch against a Coil Spring return. When the tray reaches its assigned chute, a Tilt Actuator rotates it to the dump angle and the parcel slides off. Electric sorters drive the tilt with a small Servo Motor through a Helical Gear Pair, commanded by an on-cart Actuator Board; older or simpler machines use a wayside cam and a Cam Follower to trip the tilt mechanically. Either way the tray returns to level and re-latches before it reaches the induction point again, ready for the next parcel.

Propelling the loop

The carrier train is moved by a contactless Linear Induction Drive. Wayside Linear Motor Stator linear motor stators are spaced around the loop, and each one sets up a travelling magnetic field that drags the conductive Reaction Plate mounted under every cart, so the train is pushed along without any contact between the motor and the carts. The stators wind a Laminated Core laminated core and are powered by a Linear Motor Drive that holds the train at set speed. A Speed Encoder reads cart position so the drives and the tilts stay in exact time with the loop, which is what lets a tray dump precisely over its chute at full speed.

Loading parcels on

Parcels join the loop at the Induction Stations stations. A parcel arrives on a Induction Belt that accelerates it to loop speed, while a Barcode Scanner reads its label and a Dimensioning Unit checks it fits one tray. A Photoeye confirms the next tray is empty, and the belt slides the parcel onto that tray in step with the moving loop. From that moment the control knows which tray holds which parcel and where it has to go, so induction is where the sort decision is made and locked in.

Chutes and discharge

Around the loop sit rows of Discharge Chutes. When a tray tips, the parcel falls through a Divert Plate into a sloped Chute that carries it down to a bin, a bag, or a packing station. A Chute-Full Sensor on each chute tells the control when a destination is full so it stops sending parcels there and the operator can swap the bin. The number of chutes sets how many destinations the machine sorts to, from fifty for a small store-bound system to several hundred for a national parcel hub.

Control and use

The Sortation Control is the brain. A Sort Controller holds the map from label to chute, tracks every tray around the loop, and decides exactly which tray tips at which chute. It talks to the carts through wayside Cart Comms Board boards that send the tilt command as each cart enters a chute zone, over a network tied together by a Network Switch. Operators watch the loop on an LCD Panel screen. Tilt-tray sorters come in two main forms: a single-sided loop that dumps to one bank of chutes, used where floor space is tight, and a double-sided loop with trays that tip either way to chutes on both sides, which doubles the destinations in the same footprint. Both depend on the same idea, a dedicated addressable tray for every parcel, which is what gives the machine its accuracy across a mixed parcel stream.