New Holland Workmaster 50, Service Manual

Page: 404 / 1067

Hydraulic systems - Main lift system
(9) that is pushed by the spring of shaft (21) which in turn will position itself for the discharge position (S) . In this way
the position levers will not interfere with the functioning of the draft control levers.
By positioning the draft control lever (2) against backstop. Draft control shaft (16) is caused to rotate clockwise.
The crank (15) being an integral part of shaft (16) ,will reach its extreme position of clockwise rotation, and by means
of tension rod (17) will move roller (11) , the latter acting on the draft cam (12) . This causes flywheel (7) to rotate
clockwise which by means of function shock absorber (8) produces the anti-clockwise rotation of transmission lever
(9) thus setting the distributor shaft (21) in delivery position (C) and consequently lifting the arms.
The arms will come to a stop only as soon as the piston comes into contact with the pin of the limit stop (22) .
This limit stop, by means of tension rod (23) causes lever (9) to rotate clockwise, thereby compressing the spring of
friction shock absorber (8) and thus releasing shaft (21) which now can move to the neutral position (N) where it is
pushed outward by its spring.
Moving the draft control lever (2) toward backstop (E) , the leverage system will function in the following manner:
The crank (15) being an integral part of the draft shaft (16) , rotates counter-clockwise and by means of tension rod
(17) causes roller (11) to slide on flywheel (7) .
The roller (11) when it meets the inclined plane of the draft cam (12) , permits the counter-clockwise rotation of fly-
wheel (7) which by means of shock absorber (8) will rotate transmission lever (9) in a clockwise manner thus leaving
distributor shaft (21) free to move into neutral position (N) and continuing the movement of lever (2) , in the discharge
position (S) , causing the arms to lower.
In fact, during the initial part of the movement toward backstop (E) , of draft control lever (2) the corresponding lowering
of the arms does not happen yet.
The traction force on the top link point (20) acts on tension rod (18) in the direction indicated by the arrow (+) (positive)
causing flywheel (19) to rotate clockwise together with draft cam (12) which is fastened to the same pin.
When the inclined plane of draft cam (12) meets roller (11) , a clockwise rotation of flywheel (7) is achieved which
by means of shock absorber (8) will cause transmission lever (9) to rotate counter-clockwise thereby moving the
distributor shaft (21) into neutral position (N) and stopping the movement of the arms.
As the traction force is increased, draft cam (12) will further move roller (11) thus incrementing the movement as
described above.
The distributor shaft (21) will move from neutral position (N) to delivery position (C) causing the arms to be lifted.
When the traction force diminishes, shaft (21) will return to the neutral position or to the lowering position which will
mean an inverse movement of the leverage systems to what is described above.
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