Copyright © 2000 Rayco - All Rights Reserved
Printed in U.S.A.
RG 1635A STUMP CUTTER
RAYCO
®
50
T
ROUBLESHOOTING
Likewise, in the tongue IN/OUT circuit, the high
pressure is directed to one or the other side of the
directional control valve, through the hand of the
operator, causing the cutting boom to move in or out.
In the case of retracting IN the cutting boom, for
example, the operator pulls the IN/OUT lever toward
him, and the valve spool shifts to allow high pressure
fluid to enter the
rod
end port of the telescoping tongue
cylinder, while simultaneously the spool opens a
passage that allows fluid from the cylinder
body
end
port to exhaust through the control valve body back
to the reservoir, where the oil is then recycled through
the hydraulic system. When the high pressure
overcomes opposing forces, the piston inside the
cylinder moves toward the exhausting body end port,
retracting the entire machine toward the trailer hitch,
and thus retracting the cutting wheel away from the
stump.
Likewise, in the boom SWING circuit, the high
pressure is directed to one or the other side of the
directional control valve, through the hand of the
operator. The circuit is similar to the cutting boom
motion circuits described above, except that two
opposing cylinders are used rather than just a single
cylinder. In the case of swinging cutting boom to the
left, for example, the operator pulls the boom SWING
lever toward him, and the valve spool shifts to allow
high pressure to the
rod
end port of the
left
cylinder
and to the
body
end port of the
right
cylinder, while
simultaneously the spool opens a passage that allows
fluid from the
rod
end port of the
right
cylinder and from
the
body
end port of the
left
cylinder, to exhaust
through the control valve body back to the reservoir,
where the oil is then recycled through the hydraulic
system.
Some additional elements enhance the boom
swing circuit.
1. A boom SWING SPEED control (10) is
included in a line which connects the two
directional control valve ports leading to the
boom swing cylinders. It is simply a hand-
operated needle valve. The farther it is opened,
the more leakage occurs between the two sides
of each cylinder, which slows down the cutting
boom swing motion. This can eliminate stalling
of the machine due to too much side pressure
against a stump, by requiring of the operator a
greater degree of lever movement for a given
change of boom motion speed.
Trouble-
Shooting
Hydraulic System
Description of Hydraulic System
The oil tank (reservoir) holds the hydraulic oil in supply
for the hydraulic circuits.
All cutting boom motion is accomplished by controlled
pressure applied within hydraulic cylinders.
That pressure is created by the hydraulic pump (8),
which is driven by the engine through a V-belt. The
hydraulic pump should require no special maintenance.
The pump, a gear type, draws hydraulic oil from the
reservoir (1), and energizes it through a high pressure
hose (11), at 2.86 GPM at 1,500 psi when engine
speed is 2,800 rpm, to the three bank control valve (9).
The control valve contains an integral relief valve
which prevents system pressure from exceeding 1500
psi. The control valves, under the influence of the
operator's hands upon the levers, control the movement
of the cutting wheel UP/DOWN cylinder (14), the
telescoping tongue IN/OUT cylinder (15), and the
SWING cylinders (16 & 17). Exhaust oil from the
control valve is routed through a return hose (18), and
back to the reservoir.
The hoses that run to the cylinder ports are attached
to respective ports of the directional control valve. In
the cutting boom UP/DOWN circuit, the high pressure
produced by the pump, is directed to one or the other
side of the directional control valve, through the hand
of the operator, causing the cutting boom to move up
or down. In the case of lifting UP the cutting boom, for
example, the operator pulls the UP/DOWN lever
toward him, and the valve spool shifts to allow high
pressure fluid to enter the
rod
end port of the lift
cylinder, while simultaneously the spool opens a
passage that allows fluid from the cylinder
body
end
port to exhaust through the control valve body back to
the reservoir, where the oil is then recycled through
the hydraulic system. As the weight of the cutting
boom is thus overcome by the high pressure, the
piston inside the cylinder moves toward the exhausting
body
end port, raising the cutting boom.
