Shibaura ST329, Operator'S Manual

Page: 29 / 72

CONTROLS, INSTRUMENTS AND OPERATIONS
27
Upper Link Compression Loads
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As the equip-
ment is pulled through the soil. the draft caused by
soil resistance tends to rotate the equipment up-
ward around the lower link hitch points. This draft
creates a pushing or compressive force on the up-
per link. When changes in soil resistance cause the
draft to increase, the compression force on the
upper link will also increase. These changes in
upper link compression, signal the hydraulic sys-
tem through internal linkage, to raise the equipment
slightly to maintain uniform draft.
WARNING
： ： ： ：
Always lower the hydraulic
lift and all other hydraulic equipment
before stopping the tractor.
SHIBAURA tractors having the Hydraulic Draft
Control option are equipped with two lever hydrau-
lic lift control systems. The operation of each sys-
tem is described below :
TWO LEVER CONTROLS
POSITION CONTROL OPERATION
The two lever control system is shown in Figure 35 .
Position control is obtained by placing the draft
control lever all the way forward and then moving
the position control lever to position the equipment
as desired. The front (position) lever is used to set
the desired working height or depth.
DRAFT CONTROL OPERATION
Draft control is obtained by placing the position
control lever in the forward position. Use the draft
control to adjust the draft setting (the lift system will
automatically maintain the selected draft as de-
scribed above).
OPERATING IN BOTH POSITION AND DRAFT
CONTROL
The position control may be used together with the
draft control as follows :
1. Set the position control lever at the maximum
desired implement depth. The hydraulic system will
not lower the implement below the preselected
depth. (This will also prevent “diving” which may be
encountered with light equipment, such as a rear
blade, when grading or backfilling.)
2. Adjust the draft control lever for the maximum
draft load (pull) desired.
The hydraulic lift system will now provide normal
draft response within the range set by the position
control. This adjustment provides more uniform
depth while maintaining an even pull in widely
varying soil conditions.
WARNING
： ： ： ：
Make sure the area is
clear of people before lowering equip-
ment.
HYDRAULIC LIFT ROCKER
The hydraulic lift rocker, Figure
36 , has two holes
for attaching the upper link, Attach the link in the
lower hole for light draft loads (cultivating) and in
the top hole for heavier draft loads (plowing)
shouwn.
Figure 36 - Hydraulic Lift Rocker
NOTE
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： ：
：
Fix the draft-arm with pin, Figure 36 , when
operating equipment without draft control.