Sidewinder Circuit - Toro Groundsmaster 3500 30807 Service Manual

Sidewinder Circuit

The gear pump (P2) is directly coupled to the hydrostat
through gear pump (P1) and driven by the engine. It sup-
plies hydraulic pressure for operating the power steer-
ing system, raising and lowering the cutting units,
operating the sidewinder unit, and replenishing the
closed loop traction circuit (charge pressure). The pump
takes its suction directly from the hydraulic tank.
During conditions of not lifting or not lowering cutting
units, flow from the gear pump (P2) is by- passed
through the power steering valve, 2- spool lift/sidewind-
er valve, and hydraulic manifold directly to the hydrostat
and the charge relief valve. Flow then returns to the gear
pump inlet and hydraulic tank.
Move Right (Extend)
When the sidewinder is to be shifted right, the 2- spool
valve is positioned by moving the cutting unit shift lever
to RIGHT. Flow is directed to the cap end of the side-
winder cylinder. Hydraulic pressure against the cylinder
piston moves the rod causing the sidewinder cylinder to
extend (move right). At the same time, the piston pushes
the hydraulic fluid out of the cylinder, back through the
Groundsmaster 3500
spool valve and hydraulic manifold, and to the hydrostat.
When the cutting unit shift lever is released, spring ac-
tion returns the valve to its original position and by-
passes flow back to the hydrostat and stopping cylinder
movement. The cylinder position is locked in place since
there is no complete circuit of flow to or from the side-
winder cylinder when the lever is released.
Move Left (Retract)
When the sidewinder is to be shifted left, the 2- spool
valve is positioned by moving the cutting unit shift lever
to LEFT. Flow is directed to the rod end of the sidewinder
cylinder. Hydraulic pressure against the cylinder piston
moves the rod causing the cylinder to retract (move left).
At the same time, the piston pushes the hydraulic fluid
out of the cylinder, back through the spool valve, hydrau-
lic manifold, and to the hydrostat. When the cutting unit
shift lever is released, spring action returns the valve to
its original position and by- passes flow back to the hy-
drostat stopping cylinder movement. The cylinder posi-
tion is locked in place since there is no complete circuit
of flow to or from the sidewinder cylinder when the lever
is released.
Page 5 - 27 Hydraulic System