Tiger-products-co-ltd TWR-180 User Manual download pdf (Page 33)

Assembly Section 3-7

ASSEMBLY

TWR-180 / TWR-120 12/04

The hydraulic phasing cylinder kit requires one double acting hydraulic circu it for operation. The system is

comprised of three hydraulic cylinders with depth stop collars, and allow s all wheels to be raised and lowered

simultaneously.

Before operation all air must be purged from the hydraulic lift circuit. Fully raise the cutter and hold the tractor’s

hydraulic control lever forward for 5 minutes to allow oil to fully circulate through the phasing cylinder circuit.

During operation the phasing cylinders should periodically be phased. The hydraulic lever should only have to be

held for 10-15 seconds to ensure system is phased.

Hydraulic Phasing Cylinders

A hydraulic phasing cylinder system works by

synchronizing the operation of a number of

hydraulic cylinders so that they extend and

retract at exactly the same rate. This allows a

multi-section machine such as a rotary cutter to

be raised and lowered evenly across its width.

Because a hydraulic cylinder has a ‘cylinder rod’

attached to the ‘piston’ the effective area on the

rod side of the cylinder is less than the basic

effective area of the cylinder.

In order to achieve synchronization cylinder diameters are

reduced as cylinders are connected to the ‘main cylinder’ so that

the effective area of the upstream cylinder on the rod side is the

same effective area of the downstream cylinder on the piston side.

The result of this stepping down of cylinder diameters is that all

cylinders move at the same rate resulting in a ‘level lift’.

Rephasing Groove

Hydraulic oil moves from one cylinder to the next through and indentation in the cylinder wall known as a

‘rephasing groove’. When the cylinder is fully extended this groove creates a bypass over the piston main seal,

allowing oil to flow to the next cylinder in the set. Since these grooves are quite small it will often take a number

of minutes for oil to completely circulate through the set of cylinders.

On initial startup of a phasing cylinder system it may take a number of minutes to force oil through the system and

purge out any air in the hydraulic lines. During normal operation small amounts of oil may leak past piston seals

causing cylinders to fall out of synchronization. Synchronization can be restored by fully extending cylinders and

holding the circuit open for period of time.

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Tiger-products-co-ltd TWR-180 User Manual Page 33