The Howard HK32 is a PTO-driven ground cultivator, designed for agricultural soil preparation. It is available in two main gearbox configurations: a three-speed lever change gearbox (HK32D) or a two-speed lever change gearbox (HK32ZS). The machine is suitable for attachment to tractors equipped with standard three-point linkage, specifically Category 2 or 3, depending on the model.
Function Description:
The HK32 Harrovator is designed to efficiently prepare seedbeds by cutting through soil and managing stones, while retaining moisture in the lower soil layers. Drive is transmitted from the tractor's PTO through a PTO shaft, which includes an overload safety clutch unit, to the gearbox. From there, a heavy-duty gear train drives pairs of contra-rotating blades. The machine's operational characteristics, such as blade rotational speed, cultivation depth, and tractor forward travel speed, can be varied to produce a range of tilths suitable for most soil types. It is particularly effective for quickly and economically producing seedbeds.
Important Technical Specifications:
The HK32 series includes several models, each with specific dimensions and power requirements:
- HK32-250 D: Tillage Width: 250 cm, Overall Width: 260 cm, Weight: 950 kg, Power Requirement: 50-125 kW (70-170 HP), Number of Rotors: 10, Noise Level: ≤70 dB(A).
- HK32-300 D: Tillage Width: 300 cm, Overall Width: 309 cm, Weight: 1050 kg, Power Requirement: 60-125 kW (80-170 HP), Number of Rotors: 12, Noise Level: ≤70 dB(A).
- HK32-350 D: Tillage Width: 350 cm, Overall Width: 360 cm, Weight: 1300 kg, Power Requirement: 70-125 kW (95-170 HP), Number of Rotors: 14, Noise Level: ≤70 dB(A).
- HK32-400 D: Tillage Width: 400 cm, Overall Width: 407 cm, Weight: 1450 kg, Power Requirement: 75-125 kW (100-170 HP), Number of Rotors: 16, Noise Level: ≤70 dB(A).
These weights are specified with an R8-crumble roller but without a levelling bar.
Gearbox Specifications:
- HK32D (Three-speed): Can be supplied for either 540 or 1000 rpm tractor PTO. The lever positions (1, 2, 3) provide different blade speeds (e.g., 250, 300, 360 rpm for 540 rpm PTO; 270, 330, 400 rpm for 1000 rpm PTO).
- HK32ZS (Two-speed): Standard for 1000 rpm PTO, offering rotor speeds of 274 and 318 rpm. Other rotor speeds are possible by changing select gears, and conversion to 540 rpm input speed is also possible, though not recommended.
Rotor Units:
The rotor units are equipped with tapered roller bearings (C) designed to handle high radial and axial loads. A precisely machined spacer (D) ensures optimal bearing function. The crown nut (E) clamps the components tightly onto the rotor, tightened to a torque of 600-650 Nm.
Usage Features:
- Depth Control: Tillage depth is regulated by a rear-mounted open Crumble Roller or Packer Roller. The roller is free-floating, and depth can be adjusted by changing the pin on the L.H. and R.H. sides of the adjustable upper stop pins.
- Levelling Bar (A): A rear-mounted levelling bar, attached to two floating arms (C) and adjustable vertically by spindle (B), ensures a level and even seedbed by breaking down clods.
- Side Plates (D): These restrict outward movement of soil, preventing ridges from forming between worked areas. They should be adjusted to the working depth and can move outwards in stony conditions.
- Wheel Mark Eradicators: Spring tine eradicators can be mounted on the front tool bar to eliminate tractor wheel marks. They are adjustable in operating depth and laterally to ensure optimal positioning behind tractor wheels.
- Combi-Hitch (optional): A rear linkage system that allows attachment of additional equipment like seeders, toolbars, or PTO-driven injectors. A hydraulic Combi-Hitch option further enables weight transfer of the mounted implement closer to the tractor, reducing required lifting force and improving transport stability.
- Blade Selection: Howard Harrovator blades (A) are specifically designed for efficient soil cutting and stone handling. Bent, worn, or broken blades should be replaced immediately with original Howard bolt assemblies (B), tightened to 260 Nm.
- Overload Clutch: The PTO shaft is fitted with an overload safety clutch (friction or cut-out type) to protect both the tractor and the Harrovator from damage during overload conditions. Friction clutches (204066248, 204056754) are adjusted by tightening nuts evenly. Cut-out clutches (204007982, 204007996, 204057194, 204057192, 204057193) are preset and automatically re-engage after clearing the obstruction and re-engaging the PTO at idling speed.
Maintenance Features:
- Pre-Operation Checks: Before use, ensure the Harrovator is on firm, level ground with the parking prop lowered. Check all guards, covers, warning labels, and safety devices are correctly fitted. Inspect the work area for obstructions.
- Lubrication: The main gearbox is delivered with SAE 85W-140 oil, and the gear train housing is filled with 00-consistency grease. Oil levels should be checked before first use: to the dipstick mark for the 3-speed gearbox (6.5 L) and to the oil level plug for the 2-speed gearbox (8 L). The gear train grease level should cover the lower edge of the gears by at least 10 mm. All oil and grease points, including the PTO shaft, should be lubricated as detailed in the lubrication chart.
- Fastener Checks: All bolts, nuts, and fasteners, especially blade bolts, must be tight. Re-tighten them after the first hour of work.
- Blade Maintenance: Regularly inspect blades for wear or damage and replace as necessary.
- Crumble Roller Scrapers: Periodically adjust the scrapers (C) on the crumble roller. Set the roller on level ground and slip scrapers forward until they lightly touch the tube. Clean and oil the roller after each use to prevent clogging.
- PTO Drive Shaft: Always ensure the PTO drive shaft guards are undamaged, securely fitted, and rotate freely. The guard tubes must not separate or jam, and a minimum overlap of 200 mm is required in working position. Sliding surfaces and bearings should be clean and lubricated.
- Storage: When disconnecting the Harrovator, ensure it is stable and fully supported. The PTO shaft should be placed in its designated support.
Safety Precautions:
The manual emphasizes safety, requiring operators to read and understand the instructions, wear appropriate safety gear (footwear, gloves, earmuffs), and avoid loose clothing. It highlights the importance of maintaining a safe distance (minimum 10 meters) from rotating parts and thrown objects. Never operate the machine without guards, perform adjustments while running, or work on excessively steep slopes. During transport, adhere to all road traffic regulations, ensure proper lighting and warning signs, and maintain adequate front axle load on the tractor (at least 20% of the tractor's unladen weight). The PTO drive shaft angle must never exceed 40 degrees.
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