Reach Truck

Overview

A reach truck is an electric forklift built for narrow warehouse aisles. Its defining feature is the Reach Mechanism: the whole mast slides forward on a pantograph carriage so the forks can place a pallet into a rack that sits beyond the truck's wheels, then retract so the body stays narrow while travelling. This lets a warehouse run aisles of 2.5-2.9 m where a counterbalance forklift would need 3.5-4 m. The truck carries the load between two forward Straddle Leg, so it does not need the large rear counterweight of a sit-down forklift. It serves single- and double-deep racking up to roughly 13 m, and is the standard machine for high-bay storage of palletised goods.

Reach trucks are battery powered and run indoors on smooth concrete. The operator usually stands or sits sideways in a compartment at the rear, with the mast and load in clear view down the aisle. Lift, reach, tilt, sideshift, travel, and steering are all electrohydraulic or electric, coordinated by a vehicle controller.

Chassis and counterweight

The Chassis and Counterweight is a welded steel frame that ties together the drive unit, the mast, and the battery box. Two forward Straddle Leg project under the load, each ending in a Load Wheel with a polyurethane tread that takes the load reaction. A sprung rear Caster Wheel keeps the chassis stable over floor joints. Because the legs bracket the load forward of the wheels, a reach truck needs far less ballast than a counterbalance truck. The Counterweight is a modest cast iron mass low in the frame, and the heavy battery itself acts as additional ballast. The battery sits in a Battery Compartment with a roll-out Battery Tray on rollers so a depleted pack can be swapped for a charged one in a few minutes.

Mast and forks

The Telescopic Mast is a multi-stage telescopic mast. Stacked steel channels nest inside each other and slide on hardened Mast Roller guides. The main Lift Cylinder rams raise the telescoping stage, and a centre Free-Lift Cylinder raises the carriage within the collapsed mast height, which matters when working through a doorway or under a low beam. Lift Chain leaf chains run over sheaves to double cylinder travel into carriage travel. The Fork Carriage runs up the inner channel on its own rollers and carries two forged Fork Arm tines. The carriage also holds a Fork Tilt Cylinder that pitches the forks a few degrees to cradle a load at height, and a Sideshift Cylinder that slides the forks left or right to line up with a pallet without repositioning the truck. A Lift Height Encoder on the lift sheave reports fork height so the controller can slow the mast near the top and support rack-position selection.

Reach mechanism

The reach mechanism is what sets this truck apart. A Scissor Pantograph of cross-linked scissor arms carries the mast, and a double-acting Reach Cylinder extends and retracts it along Reach Rail rails set into the straddle legs. To deposit a pallet, the operator reaches the mast out over the legs, lowers onto the rack beam, then retracts. A Reach Position Sensor reports reach position so the controller can interlock travel while the load is extended.

Traction and hydraulics

The Traction Drive Unit unit combines drive and steering in one assembly at the rear. An AC AC Traction Motor drives the Steer-Drive Wheel through a reduction Gearbox Housing with Helical Gear Pair sets, while an electric Steer Motor turns the whole unit on a Steering Slew Ring slew bearing for full power steering. A spring-applied Electromagnetic Brake holds the truck when it is stopped or powered down.

The Hydraulic System supply pressure to every cylinder. A Pump Motor drives a Hydraulic Gear Pump on demand rather than continuously, which saves energy. A Proportional Valve Bank of proportional spools meters oil to lift, reach, tilt, and sideshift so the operator gets smooth, independent control of each. A Reservoir with a return filter and breather holds the oil, and Pressure Sensor units report load pressure for weight display and overload protection.

Electrical and control

The Drive Electronics and Control system runs everything from the battery DC bus. A Traction Inverter and a Pump Inverter, each built around an IGBT Power Module and a DC-Link Capacitor, drive the two AC motors. A Vehicle Control Unit built on a Compute SoC Module reads the operator inputs and sensors and commands the inverters over a CAN bus carried in the main Wire Bundle. The operator works from a Operator Compartment compartment with a Steering Tiller, fingertip Control Levers, a traction pedal, and an Operator Display built on an LCD Panel that shows battery state, lift height, load weight, and fault codes.

Safety and battery

The Safety and Signalling group covers an Overhead Guard over the operator, an Emergency Stop, a horn, LED work lights, a warning beacon, and Limit Switch interlocks. Power comes from a Traction Battery built from Battery Module units of Li-ion Cell, 21700 cells, or a lead-acid pack on older trucks, managed by a Battery Management System and housed in a heavy steel Battery Case that doubles as ballast.

Variants and use

Reach trucks come as stand-on or seated models, with single- or double-deep reach, and with mast heights chosen for the rack. Cold-store versions seal the electronics and hydraulics against condensation. Some carry camera systems and height pre-select to speed work at the top of tall racks. The machine is the backbone of high-bay pallet storage, where aisle width drives the cost of the building and the reach mechanism buys back floor space that a counterbalance truck would waste.