Tuesday, August 22, 2006
Four-wheel drive option for new mower
Howard Price Turf Equipment, the Chesterfield, Mo., manufacturer of commercial turf care equipment, has introduced a new mower targeted to commercial lawn care professionals in landscaping and municipal applications. The new Hydro Power 1280 mower is powered by a choice of two Yanmar diesel engines and features an optional hydrostatic four-wheel drive system.
The standard engine is the four-cylinder, naturally aspirated Yanmar 4TNE88 diesel engine rated 52 hp at a mechanically governed speed of 3100 rpm, with 101 lb.ft. of torque at 1600 rpm. The 133.5 cu.in. engine features direct injection, 18.0:1 compression ratio, forced lubrication system via an integral trochoid pump, a Nelson muffler, and a Donaldson RadialSeal air filter with dual element filter and dust unloading valve.
The optional engine is a four-cylinder, water-cooled, Yanmar 4TNE84T turbocharged diesel engine rated 61 hp at a maximum governed speed of 3100 rpm, with 101 lb.ft. of torque at 1600 rpm. This engine uses a Yanmar supplied muffler.
Engine accessories for these engines include a 400 W electric intake air preheater designed to aid in cold starting; mechanical fuel feed pump with replaceable 120 micron fuel filter/water separator; 12 V, 40 amp alternator; and Radiator Specialties 7 fins per in. radiator and oil cooler assembly.
The engine drives a 2.48 cu.in./rev hydrostatic pump through a Guardian Industries hydraulic pump drive system. The pump's maximum system flow is 32 gpm. A mechanical linkage, connected to an operator-actuated traction foot pedal, controls the variable forward/reverse ground speed through a servo control valve. This design is intended to give the operator smooth and easy control of the transmission pump.
The hydrostatic transmission powers Eaton series 2000 wheel motors, each with a displacement of 14.9 cu.in./rev, which drive the front wheels. The optional four-wheel drive system includes two Eaton series 2000 hydraulic motors, each with a displacement of 6.2 cu.in./rev, on the rear wheels. The rear-mounted turning axle assembly and four-wheel drive system are packaged by Fluidrive, Inc.
The optional four-wheel drive system, which is activated by a dash-mounted switch, has a pressure equalized flow distribution to the rear wheel motors through Fluidrive's Equa-Trac valve system. This design allows a tight turning radius, without scarring turf while in the four-wheel drive mode, while providing better vehicle traction, according to the company. Ground speed for the 1280 mower is zero to 16 mph in forward and zero to 5 mph in reverse in two-wheel drive.
Piggybacked to the hydrostatic transmission is an Ultra Hydraulics tandem gear pump providing power for the open center hydraulic system that drives the cutting blades. This pump has a displacement of 1.19 cu.in./rev and a maximum flow of 15 gpm at each section. One section of the pump powers the front mower deck while the other section of the pump provides power in a series circuit for the two wing decks. The system is limited to 3000 psi.
An electrohydraulic manifold block with solenoid switch from Sterling Hydraulics controls on/off, braking and pressure relief functions. The blades are driven by Ultra Hydraulics gear motors with 1.16 cu.in./rev displacements.
The mowing deck raise and lower functions, as well as the power steering system are powered by a third Ultra Hydraulics gear pump. The mower deck hydraulic lift system has a relief pressure of 2000 psi. The cylinder for the front deck has a 2 in. bore x 4 in. stroke, and each wing deck is raised by a single 2 in. bore x 10 5/16 in. stroke cylinder.
Mower deck raise and lower functions are controlled by three separate three-position valves. The lift valve function includes an automatic float position. Each deck lift system also incorporates a limit switch to automatically cut hydraulic power to the blades if the deck is raised vertically more than 20[degrees] above the horizontal plane. The wing decks can also be used to aid in wheel traction or weight balance for different mowing conditions by raising or lowering the deck off the ground.
The steering system is a full hydraulic power system with a supply pressure relief setting of 1000 psi. An Eaton Char-Lynn series 2, nonload reaction-type steering valve controls a 1.75 in bore x 7 in. stroke steering cylinder.
The hydraulic system uses a 15 gal. reservoir with an in-tank filter screen on the suction line. A 10 micron, full-flow spin-on Donaldson filter is located on the pressure side of the Eaton hydrostatic transmission charge pump, while a Zinga spin-on full-flow 10 micron filter is used in the return circuit before the fluid returns to the sump.
The parking and service braking is provided by two individual 9 in. x 2 in. drum brakes on the front traction drive wheels. Each wheel can be independently operated by individual foot pedals to assist steering. Braking assist is also provided by the dynamic braking effect of the hydrostatic traction drive system.
Instrumentation and controls for the 1280 mower consist of a Datcon hour-meter, fuel gauge and water temperature gauge. The indicator lights, also from Datcon, include one each for mower blade and cruise control engagement, four-wheel drive engagement and hydraulic filter restriction, battery, parking brake engagement, engine water temperature and engine oil pressure. Audible alarms are also included for low oil pressure and high engine coolant temperature.
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