MTZ 1220.1, Operator'S Manual

Page: 90 / 244

MTZ 1220.1/1220.3 Section D. Construction and Operation
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Fig.. D-30. Hydraulic power lift construction:
1 – monoblock; 2 – draft sensor leverage; 3 – position sensor; 4 – RHL lifting levers shaft; 5 – regulator-
distributor; 6 – position lever; 7 – draft lever; 8 – lid; 9 – position sensor leverage; 10 – lifting levers; 11 –
shackle axle; 12 – draft sensor coupling link; 13 – pin; 14 – draft sensor rod; 15 – cover; 16 – adjusting shims
for draft sensor spring; 17 – draft sensor spring; 18 – dish; 19 – nut
The control unit is mounted in the mon-
oblock (1) (Fig. D-30) and consists of a
position sensor in the form of a bracket
attached to shaft (4) of the RHL lift lev-
ers (10); draft sensor involving the cou-
pling link (12) mounted on axle (11) in
the monoblock (1) and coupled with rod
(14) on pin (13). The spring (17) pre-
loaded by the nut (19) is fitted on the rod
(14). Through a leverage system (9) the
position sensor (3) is connected to posi-
tion handle (6). The pin (13) of the rod
(14) is coupled with draft handle (7)
through leverage (2).
The control unit operates as follows:
When the position control is used, the
draft handle (7) (Fig. D-30) should be
shifted to its foremost position, in the di-
rection of the tractor forward travel. Fur-
ther control of the hitch linkage is
achieved by means of the position lever
(6) (Fig. D-30) and handle (7) via ropes
(5) (Fig. D-29). When moving the lever
(6) backward, the hitch linkage is lifted
and then moving the lever (6) forward,
the hitch linkage is lowered. This adjust-
ing process is performed by means of
the regulator-distributor built in the mon-
oblock (1) and controlled be means of
the position sensor (3).
When the draft control is used, the
position handle (6) should be shifted to
its foremost position, in the direction of
the tractor forward travel, corresponding
to the bottom position of hitch drop links.
The draft control handle (7) is set to the
required ploughing depth; further the
process of adjustment is fulfilled by the
built-in regulator-distributor (5) under
control of the draft sensor.
Using the position control handle (8) (8)
(Fig. D-29) for limiting the ploughing
depth when operating in the draft control
mode makes it possible to achieve the
combination adjustment.
The Regulator-Distributor (5) built-in
into the monoblock (1) is an adjusting
element of the hydraulic power lift. It is a
slide-valve gauge whereby the operating
position like “Lift”, “Drop”, “Neutral” and
RHL automatic control can be achieved.
The hydraulic power lift drive (Fig. D-29)
consists of a bracket (4) with the draft
(7) and position (8) handles mounted on
it. The latter are connected to the draft
(11) and position (10) levers, respec-
tively, by means of two-way ropes (5).
The control levers are locked by spring-
loaded
friction disks.