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472H Potato Harvester Owner Operator’s Manual
3.20.4 HARVESTING EFFICIENCY
Studying procedures and facts of mechanical harvesting can
help operate the harvester at maximum efficiency with mini-
mum cost.
A potato harvester normally works under a heavy load. For
each 1/2" of depth, a digger blade lifts an average of 150
tons of soil per acre. Harvesting 2 rows at a speed of 2
m.p.h. with the digger blades at a depth of 4" means that
the belted chains lift an average of 6 to 10 tons of soil per
minute. Operating just 1/2" deeper requires the belted chains
to lift another ton or more of soil per minute. Each ton of dirt
lifted requires more power and fuel expended and may pro-
duce only a few more potatoes. Thus, maximum harvesting
efficiency and economy may mean recovering less than
100% of the crop. The additional power, fuel, and time re-
quired to lift an extra inch or two of soil, plus the probability
of reducing the separating efficiency, may be more expen-
sive than the value of a few potatoes left in the field. For
example, harvesting 98% of your potatoes may result in
more net profit than digging two inches deeper and harvest-
ing 100%. Consider this factor as you begin harvesting. Com-
pare costs of maximum recovery and maximum efficiency
in determining the most efficient digging depth in your situ-
ation.
Regardless of digging depth, blades should scour freely for
best digging action. Watch for spill-out around the ends of
the blades. Excessive spill-out may require the use of an-
other type of blade or that the speed of the primary belted
chain is too slow relative to forward travel speed.
Carry the soil two-thirds or three-fourths of the way up the
primary belted chains. This provides maximum protection
for the potatoes. The pitch and speed of the belted chain
and the amount of shaker agitation determines soil separa-
tion.
3.21 GENERAL LOW DAMAGE PO-
TATO HARVESTING
Lockwood has always recognized that potato bruising con-
cerns the grower greatly and constantly searches for im-
proved methods of bruise reduction. Proper operator train-
ing has the most effect on potato bruising and is the most
controllable. The following section on low damage harvest-
ing contains suggestions for the operator and discusses
machine functions which you may use to maximize the quali-
ties built into the Lockwood harvester.
3.21.1 DIGGER BLADES
The performance and depth control of the digger blades will
help control bruising. Adjust the blade, regardless of type,
for the proper digging angle to allow correct feeding of pota-
toes onto the primary belted chain. Adjust blades so that
potatoes do not bump into the front of the primary belted
chain. Keep the blades scoured and sharp to maintain even
flow of dirt and potatoes into the primary area. Improper
blade angle or poor scouring will cause the potatoes to “boil”
ahead or spill out the sides of the digger nose.
Digging too deeply will result in carrying much more dirt into
the machine than necessary and will increase the amount
of power required to pull the harvester.
The belted chain normally used is 45 - 56 mm pitch chain
on the primary digger section and 45 mm - 50 mm pitch with
rubber covering on the secondary section. The design of
these pitches provide for the best separation under the wid-
est range of conditions. Your Lockwood Dealer has other
patterns and pitch lengths available.
3.20 OPERATING HINTS
The belted chains in the harvester perform two major func-
tions: they convey the dug material and provide separation
of the soil and trash from the potatoes. The belted chain
pitch determines the capacity of the belted chains. The belted
chain speed and forward harvester ground speed affect the
material volume the belted chain can carry. In order to ob-
tain the lowest crop damage possible, maintain proper load-
ing onto the belted chains. Provide potatoes with a “cush-
ion” to minimize damage while eliminating as much dirt and
trash as possible to achieve proper loading. Varied engine
RPM and gear selection will change the belted chain speed
relative to the ground.
Operating at too shallow of a depth will cause the blades to
cut potatoes or miss them entirely. Check the digging depth
at the beginning to verify proper harvesting of the crop.
3.21.2 BELTED CHAINS:
