Forwarder Product

Overview

The forwarder is a self-propelled wheeled harvester designed to collect felled logs from the stump and transport them to the roadside landing. Unlike skidders that drag logs, forwarders load logs into an elevated cargo Cargo Bunk using a loader Loader Crane with a hydraulic Grapple Unit. The wheeled chassis provides excellent road-going capability, making forwarders indispensable for long-distance log hauling in mechanized forestry.

The machine consists of an articulated frame connecting a front Chassis Frame with steering Front Axle Assembly, engine compartment, and rear bunk mounted on a turntable pivot. A forwarder-diesel-engine powers a variable displacement pump supplying proportional Hydraulic System to the boom, grapple, and steering systems. The Bogie Axles with dual wheels per side carry 25 tonne loads on forest roads.

How it works

The operator controls the forwarder from an air-suspended Operator Cabin using a multi-axis proportional Joystick Control. The engine drives a Main Pump supplying 250 bar through a Proportional Valve to all actuators.

To load logs, the operator articulates the frame using steering cylinders in the Steering Cylinder, positioning the crane base over the log pile. The Crane Rotation Motor rotates the boom, extending the Main Boom using its Boom Lift Cylinder. The secondary Knuckle Boom with its Knuckle Cylinder articulates for precise placement. The operator opens the Grapple Unit using proportional pilot signals, closes it around the log, and retracts the boom to stack the load in the bunk.

The Grapple Frame houses four Left Grapple Finger and Right Grapple Finger fingers actuated by paired Grapple Cylinder cylinders. The grapple can rotate ±180° via the Grapple Rotator motor, allowing logs to be oriented lengthwise or crosswise in the bunk. A typical load cycle takes 2–3 minutes per log.

Once the bunk is full (20–25 tonnes), the operator drives toward the landing using steering via the Steering Cylinder. The articulated Main Frame Beam and Articulation Hinge allow the chassis to bend up to ±25°, maintaining wheel traction on uneven terrain. The Bogie Axles with air-suspended Air Spring absorb ground shock, protecting the load and operator.

At the landing, the operator reverses into position and uses the crane to unload logs one by one onto the log deck. The Brake Circuit provides proportional braking through Brake Caliper calipers on all wheels, with pilot pressure modulated by the operator's foot pedal through the proportioning valve.

Crane and Grapple Design

The Loader Crane is a knuckle boom system comprising a main boom and articulated knuckle, reaching 12–14 m total length. The Main Boom is a seamless steel box tube 280×250 mm, lifted by a Boom Lift Cylinder rated 120 mm bore at 250 bar. The Knuckle Boom is a secondary 4 m segment articulated via a Knuckle Cylinder, enabling the grapple tip to reach over the bunk frame and place logs precisely without collision.

The Grapple Unit delivers 35 tonne clamp force from paired cylinders. The Grapple Frame is a ductile iron casting 800 mm wide with fingers extending 1200 mm. Each finger is hardened steel with an elastomer pad to prevent log crushing. The Grapple Rotator motor enables 360° rotation, allowing the operator to orient logs horizontally along the bunk or vertically to maximize capacity.

Chassis and Suspension

The forwarder sits on two rear Bogie Axles rated 15 tonne per side, plus a single front Front Axle Assembly for steering. Each rear axle is a cast ductile iron tube with 5:1 final drive gearing connected to a hydraulic motor. The Wheel Hub Assembly uses dual wheels (750×400 mm) per side, providing excellent traction on soft ground.

The Air Spring suspension on each bogie absorbs road shock, maintaining operator comfort and load stability. The Brake Caliper disc brakes on all axles are modulated by a proportioning valve connected to a pilot-operated accumulator, delivering smooth proportional stopping force.

The articulated frame hinge at Articulation Hinge uses a spherical bearing allowing ±25° articulation. This flexibility is critical for forest roads that lack grading, allowing the machine to crab over ruts and rocks while maintaining all wheels on the ground.

Bunk and Load Security

The Cargo Bunk is a 6 m × 2.5 m platform with a 15 mm steel Load Deck Plate featuring a raised pattern to prevent log rolling. Four removable Stake Assembly stakes (1.8 m tall) are bolted to the frame, providing lateral containment. Four lever-ratchet Chain Tensioner chains secure the load, each rated for 5 tonne tension.

Typical loads are 20–25 tonnes of mixed logs, or 12–15 long logs (30+ m length) loaded singly. The bunk turntable mounted on the Crane Mounting Turntable permits the entire rear section to rotate relative to the front frame, improving maneuverability on narrow forest roads and unloading precision.

Fuel and Power

The Diesel Engine is a turbocharged 6-cylinder diesel rated 200–250 kW, meeting Euro 3 emissions. The Fuel Tank holds 250 L, providing 8–10 hours of operation on a full tank. The Radiator is an aluminum bar-plate design driven by a variable-speed fan, maintaining optimal engine temperature during high-load cycles.

A modern forwarder can transport 80–120 tonnes per shift depending on log size and road distance, making it a critical productivity tool in industrial harvest operations.