Tow-Behind Leaf Vacuum Loader

Overview

A tow-behind leaf vacuum loader is the machine municipalities and grounds contractors use when leaf volume outgrows blowers and tarps: residents rake leaves to the curb, and the loader follows the truck, inhaling the piles. It is a pneumatic conveyor. An engine-driven Impeller Assembly generates a high-velocity airstream; leaves entrained at the Pickup Nozzle travel up the Intake Hose, pass through the impeller, which shreds them roughly 4:1 by volume, and are blown out the Discharge & Trailer Interface into a trailer or truck box. One operator on the nozzle and one driver replace a raking crew, moving up to about 25 m³ of loose leaves per hour.

The whole machine rides on the Trailer Chassis, a single-axle trailer towed behind the collection vehicle so the discharge chute hangs over the receiving box.

How it works

The Engine Assembly is a governed 627 cc V-twin with the impeller mounted directly on the crankshaft stub through a Taper Hub, no belts or gearbox, so the fan turns at engine speed and the only drivetrain maintenance is the engine itself. At 3,600 rpm the 740 mm Impeller Disc gives blade tip speeds around 140 m/s, producing roughly 4,200 m³/h of flow and 35 m/s of air velocity at the nozzle mouth.

Velocity is the design currency. Wet maple leaves need conveying air above roughly 25 m/s to stay entrained in a vertical hose run; below that they fall back and slug the hose. This is why the flared Pickup Nozzle matters more than it looks: its skid plate and flare meter bypass air around the pile so the hose never fully plugs, keeping velocity up even when the operator buries the mouth in leaves.

Unlike a clean-air fan, this impeller works in the material stream. Each Impeller Blade is a flat paddle of abrasion-resistant steel with a bolt-on Shredder Serration on its leading edge; leaves and small twigs crossing the eye are struck at over 100 m/s and cut against the serrations. Shredding is not cosmetic, the 4:1 volume reduction is what makes the haul economical, quadrupling the payload of each trip to the compost site.

The Blower Housing is a welded spiral volute that collects the swirl off the blade tips and accelerates it toward the throat. Debris scrubs the outer wall continuously, so a bolt-in Wear Liner takes the erosion and is replaced, typically every few hundred hours in gritty curbside service, instead of the Volute Case itself. Sand and gravel ingested with curb leaves are also why the engine breathes through a cyclonic Air Cleaner.

Intake boom and discharge

A 3 m length of 250 mm wire-helix hose full of moving leaves is heavy, so the hose hangs from a counterweighted Boom Arm on a Boom Swivel, letting the operator sweep about 180° of curb from one trailer position while steering only the nozzle weight.

On the pressure side, the Discharge Chute rotates to aim into the receiving box and its Deflector spreads the stream so the load fills evenly. The trailer interface is deliberately simple: two Trailer Clamps seat the chute on the box wall, and a Mesh Cover over the box does the critical separation job, it vents the 4,200 m³/h of conveying air while retaining the shredded leaves. Without a permeable cover the box pressurises and blows material back out; with a solid tarp the airflow has nowhere to go at all.

Chassis and operation

The Chassis Frame carries engine, housing and boom over a solid Axle Beam with highway-rated hubs, towed on a 50 mm ball through the Hitch Tongue with crossed Safety Chains and an LED Light Kit for legal road towing at up to 40 km/h. A Jack Stand holds the tongue when parked.

Starting is electric, from an 12 V Battery through the Ignition Switch, hand-cranking an engine with a 740 mm steel flywheel bolted to it is not practical. The Throttle Control is normally set to governed full speed and left there; conveying performance collapses quickly below rated rpm.

The hazard profile is blunt: the impeller will shred anything the hose can swallow, and curb piles hide cans, stones and the occasional brick, which exit the chute at projectile speed. Operators keep bystanders away from the discharge arc, and the serrations and liner are inspected whenever the Hour Meter flags a service interval, since a blade unbalanced by impact damage shakes the whole machine through the rigid crankshaft mounting.