Transcript Important Features for Utility Tractors 11 15 06a

Important
Features for
Utility Tractors
Herb Willcutt
MSU Ag & Bio Engineering
11/15/06
Goals
• Better understand utility tractor terminology
used by manufacturers, sales reps and
farmers
• Discuss utility tractor features important for
accessibility
Transmissions (in order of $$$)
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Gear or collar shift
Quick/Power reverser
Sync Shuttle Shift
Hydrostatic (Compact tractors under 50 hp)
Power Quad (power shift within range)
Power shift (larger tractors)
IVT (Infinitely Variable Transmission)
Range Control
• Most transmissions have 2 or 3 ranges with 3 to 5
“gears” in each range.
• I.e. 3 ranges with 4 gears + reverse in each range
provides 12 forward speeds and three reverse
speeds.
• Ranges usually indicated
• as “A”, “B” or “C”
• Ranges are used with
• other transmission types
• for speed flexibility
Gear transmission
• Clutch used for speed
or direction changes
• Least expensive
• Least productive
in loader operations
• Usually limited in
speed ranges
Quick/Power Reverse
• Ease of changing from
forward to reverse
• Must use clutch to
change speed or
direction
• Must be stopped to
change speed or
direction
Synchronized Shuttle Shift
• Provides
shifting
speeds
without
fully
stopping
Hydrostatic
• Compact tractors under 50 hp
• Infinite speed and direction control
– Great for loaders, slow speed operations and
wide range of speeds such as mowing
• Single or dual pedal operated
• Cruise feature to lock speed (release with
brake or cruise switch)
Power Quad
• Bump lever control of speed and direction
• Clutch necessary for starting (safety) and
range control only
• Each gear change will result in slight “jerk”
as speed changes for a constant engine rpm
Full Power Shift
• All speeds and reverse are shifted with
hydraulic clutch packs
• Bump lever control
• Forward to reverse without clucthing
• Slight “jerk” for each speed setting change
• Clutch necessary only for starting safety
• Usually an option only on larger tractors
IVT (Infinitely Variable
Transmission)
• Infinite transmission speeds form 0 mph to
max speed
• Dial in speed setting
• European design (and primary use)
• Combines hydrostatic and planetary gears
with computer control for smooth “jerk
free” and efficient speed control to match
the job
Remote Hydraulics
• One or two rear valves
– Mechanical actuated with
lever
– Electrical actuated with
solenoid
• Joystick (loader control)
• Placement of controls
– Joystick valves may block
right entrance and egress
(especially add on loader
valves)
PTO (Power Take Off)
• 540 RPM standard at an engine speed
• Independent
– Lever to engage shifted with clutch
– PTO controlled by hydraulic clutch pack
• Semi independent
– Push clutch to control the PTO
– Common with hydrostatic transmissions
• Two stage clutch
– Push down half way to change gears, all the way to
disengage the PTO
– Found on older tractors
Hitches
• Three point
– Fixed lower
links
– Telescoping
lower links
– Quick
hitches
Lower
Link
Stabilizer
Fixed
Drawbar
Parking Brake Actuation
• Push pedal/pull latch
• Automotive lever
• Transmission lock position
Differential Lock
• Locks all drive wheels
together
• If one drive wheel slips
other side will not stop
pulling
• Engaged on the go by
depressing a pedal with a
heal
• Releases when axle torque
on each side returns to
near equal
Front Wheel Assist
• Provides power to all 4
wheels
• Decreases rolling resistance
of front wheels
• May increase turning
radius slightly
• Better handling, traction
and stability
• Superior performance for
loaders where weight shifts
from full to empty bucket
• May increase the operator
platform height because of
tire sizes
Operator Platforms
• Open, two post ROPS
• Open, two post ROPS with canopy
– Canopy may limit access height for lifts or
for a person who cannot bend easily
• Four Post ROPS
– May limit access
• Cab
Operator Platforms
• Flat deck
• Straddle mount/Isolated
open
• Steps
– Rigid and flex
– Step height
– Right vs. left cab entrance &
egress
Steering
• Power vs manual steering
– Most late model tractors will have power
steering even on smaller tractors
• Tilt, telescoping and fixed steering shaft
– Tilt & telescope provides greater access
– Operator comfort once in seat
Tire Types
R1 Agricultural, Max traction in soft soil
R3 Turf, smooth ride
R4 Industrial, loaders, mowers, firm soil stiff sidewalls & ride
Loader Attachment Methods
Conclusion
• There are many features offered on utility
tractors that affect performance,
productivity, ease of control, access and
price.
• Choose wisely to match the tractor, options,
the job and the operator’s abilities for best
performance.