Grape Harvester Product

Overview

Mechanical grape harvesters are self-propelled machines engineered to streamline vineyard harvest operations by autonomously gripping vine canes, vibrating them to dislodge fruit clusters, and delivering grapes to a destemming unit. The design targets vineyards with dense plantings and uniform ripeness, processing 6–8 tonnes per hour with minimal fruit damage and reduced labor requirements.

The harvester straddles vine rows, positioning its shaker head to grip canes at the optimal height. A hydraulic-driven eccentric mechanism oscillates rods at 40–50 Hz, mimicking manual shaking but with consistent, high-frequency force. Dislodged clusters fall onto overhead catch plates angled inward, funneling fruit into a central chute. A conveyor belt with integral flight bars carries grapes upward to a perforated destemming drum, where rotating motion and friction separate berries from stems. Clean fruit drops into a 500 kg collection hopper for road transport to the winery.

How it works

Shaking and Catching: The operator positions the harvester straddling a vine row using proportional hydraulic steering. Pneumatic rod clamps grip canes at 1.5–2.0 m height. The hydraulic motor drives an eccentric mass at 2400 rpm; unbalance causes vertical oscillation transmitted through flexible rods to the canes. Frequency and amplitude are operator-adjustable via spool valve settings. Vibration intensity is tuned to detach mature grapes (30–40 N per bunch) while minimizing cane damage. Falling clusters are caught on V-shaped plates angled at 120° and guided downward into the collection chute.

Transport and Processing: The conveyor belt (1000 mm wide, 3.5 mm thick, nylon-reinforced) sits at 40° inclination driven by a 5.5 kW motor through a Drive Pulley. Fabric flight bars, glued at 300 mm spacing, prevent slippage and accelerate fruit upward. Speed is variable (0.5–1.0 m/s) to match flow rate from the shaker without overflow or bridging. At the top, grapes drop into the Destemmer Drum.

Destemming: The destemmer drum is a 600 mm diameter stainless steel perforated cylinder (4 mm holes) rotating at 400 rpm inside a casing. As grapes enter, they tumble against the drum surface; friction and centrifugal action separate berries from stems within 8–12 seconds. Separated berries fall through holes onto an inclined discharge screen; stems are ejected axially through a reject outlet. The screen ensures size-based separation: berries pass (6 mm holes), skins and debris are retained and blown out by the motor's centrifugal effect.

Hydraulic System: A 40 cc/rev axial piston pump, driven by the diesel engine, supplies pressurized fluid to the shaker motor (10 cc/rev displacement, 2400 rpm nominal), steering cylinder (80 mm bore, 400 mm stroke), and motorized rod clamps (50 mm bore pneumatic pilots). A 200 L steel reservoir provides residence time for thermal stabilization and sediment settling. Pressure-relief valves at 210 bar protect pump and actuators; directional control spool valves are proportionally modulated for smooth, responsive control.

Electrical and Controls: A 60 A three-phase alternator supplies 24 V DC (via rectifier) for auxiliary battery, lights, and sensor modules. Three electric motors drive the conveyor (5.5 kW), destemmer (2.2 kW), and hopper auger (0.75 kW) independently via contactors. An operator control panel (mounted on the seat post or armrest) integrates proportional joysticks for steering and shaker intensity, momentary buttons for conveyor direction and hopper discharge, and rocker switches for motor enable and emergency stop.

Chassis and Mobility: The straddle chassis is a welded 50×50 mm tube frame supporting dual 11.5/80–15.3 pneumatic tires (load index 180 per tire) on independently sprung axles. Leaf spring packs (6–8 plies, clamped at ends) isolate vibration from the engine and shaker assembly. Hydraulic dampers (piston type) attenuate oscillations at 1–2 Hz, crucial for ride comfort and operator safety on rough orchard terrain. Maximum slope negotiable is 12°; the steering geometry is Ackermann-type with a turning radius of 6 m at full lock.

Harvest Operations

Typical deployment: one harvester, one tractor with bulk bins or trailer, and one assistant operator per machine. The harvester moves down the row at 1.5–2.0 km/h (adjustable walk speed via engine throttle), stopping every 10–15 vines to harvest. The shaker is engaged for 4–6 seconds per vine; fruit drops into the hopper. When full (30–40 seconds of continuous harvesting), the auger is engaged, discharging fruit into a waiting bin on the parallel vehicle. Row work continues until the field block is complete, typically 6–8 hours for a 2-hectare section.

Maintenance Windows: After 40 hours of operation, change the hydraulic filter element (return line, 10 µm absolute). Every 160 hours, drain and replace hydraulic fluid (ISO VG 46, anti-wear zinc-based). Inspect rods, clamps, and elastomeric bushings monthly; replace if tears, cracks, or permanent set exceeds 25%. Belt tension (checked every 20 hours via deflection) should be maintained at 10–15 mm mid-span. Destemmer drum perforations block after 60–80 tonnes; clean with soft brush or replace if damaged.

Fruit Quality: Mechanical harvesting captures 95–98% of ripe grapes with <5% damage rates on cultivars suited to the method (e.g., Cabernet Sauvignon, Concord). Destemming efficiency (berries separated cleanly from stems) exceeds 90% when flow rate and drum speed are balanced. Oxidation is minimal because fruit residence time from harvest to hopper is <5 minutes, and the sealed hopper protects from light and air exposure during transport.