Final project for an applied fluids and hydraulic class.

1. MET 230 Team Project Brian Backner
Spring 2016 Joe Legan
The Problem
Rough terrain forklift. Pg200, Figure 6-1. Do not include servocontrols,onlyDCVs. Mustinclude the
followingcontrols: Angularcontrol of the bar (750 lbsweight,with6000 lb liftingcapacity). Extension
control of the bar. Extensioncontrol of the forks. Rotational control of the forks. Include safetydevices
that will notletthe loadfall if powerisremovedfromthe pump.
Assumptions
Goingoff of a similardesignwe are usingthe followingassumptions:
 The maximumliftweightisat12’ in frontof the vehicle
 Total arm lengthis55’ witha maximumheightof 45’
 Engine powerof 100 hp
 Operatingpressure forthe systemis3000 psi
 Time for full extensionis16 seconds
 Time for liftis12 seconds
 Pump90% efficient
 The duty cycle of everythingbutthe primaryliftingandextensioncylindersisnegligible

2. MET 230 Team Project Brian Backner
Spring 2016 Joe Legan
Class 3 Lever
Fcyl = [(L1 + L2)/L2 x Cos()]*Fload => (30/9) x 6750 = 22500 lbf
Lift
A = F/p => 22500 lb/3000 psi = 7.5 in2
Boom
A = F/p => 6000 lb/3000 psi = 2 in2
Volume of Flow Needed
Lift - 102” x 7.5” = 382.5 in3
Boom Extension – 655.2” x 2.5 in2
= 1638 in3
Fork Extension – 24” x 2.5 in2
= 60 in3
Heat Loss
Lift – 765 in3
/12 sec => 16.6 gpm
Boom – 1638 in3
/16 sec => 26.6 gpm
Pump – [(1/.9 – 1)(3000 psi x 50 gpm)] / 1714 = 9.72 hp
Lift – (3000 psi x 16.6 gpm)/1714 = 29.1 hp
Boom – (3000 psi x 26.6 gpm)/1714 = 46.6 hp
Total hp loss 85.42 x 2544 = 217308 BTU/hr
Thisfigure isassumingall systemsare running100% of the time,inrealitythisnumberwillbe muchlower
due to the nature of how a forklift is used.
Sequence Flow Chart
Boom Angular Control
UP
• Controlsare operatedcausingSolenoidA toenergize.The DCV shiftsrightaligningportsPandA.
• Fluid begins flowing through the Check valve, bypassing the counter balance valve and into the
piston side of the cylinder.
• Fluid from the rod end of the cylinder flowsout and into the B port of the DCV and back to the
tank.
• Once at limitof the range of motionthe pressure increasesandthe internal pilotof the pressure
relief valve opens.

3. MET 230 Team Project Brian Backner
Spring 2016 Joe Legan
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir.
Down
• Controlsare operatedcausingSolenoidBto energize. The DCV shifts left aligning ports P and B.
• Pressure builds causing the external pilot of the Counter Balance Valve to open the valve.
• Fluid begins flowing out of the piston side of the cylinder and back to the tank.
• Once at limitof the range of motionthe pressure increasesandthe internal pilotof the pressure
relief valve opens.
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir.
Boom and Fork Extension
Extension
• Controlsare operatedcausingSolenoidA toenergize.The DCV shiftsrightaligningportsPandA.
• Fluidflowsoverthe CBV checkvalve on the pistonendof the Boomcylinderwhile fluidfromthe
rod end flows through the Sequence Valve check valve and back to the B port.
• Fluidflowsfromthe T port through the filterand oil to air heat exchangeronit wayback to the
reservoir.
• Once the Boom cylinder reaches full extension the internal pilot of the Sequence Valve opens
allowing fluidto flow through the check valve of the CBV and into the piston end of the Fork
Cylinder.
• Fluid flows from the rod end of the Fork Cylinder and through the Filter and Oil to air heat
exchanger on its way back to the reservoir.
• Once at limitof the range of motionthe pressure increasesandthe internal pilotof the pressure
relief valve opens.
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir.
Retraction
• Controlsare operatedcausingSolenoidBto energize.The DCV shifts left aligning ports P and B.
• Pressure is applied to the rod end of the Fork Cylinder, this opens the external pilot of the CBV
and fluid begins flowing out of the piston end of the cylinder.
• Once the Fork Cylinderisfullyretractedandthe pressure increasesopeningthe Sequence Valve
and allowing pressure to be applied to the rod end of the Boom Cylinder.
• The pressure opens the pilot of the Boom Cylinder CBV and fluidflowsout of the piston end of
the cylinder and back to the B port of the DCV.
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir

4. MET 230 Team Project Brian Backner
Spring 2016 Joe Legan
• Once at full retraction the pressure increases and the internal pilot of the pressure relief valve
opens.
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir
Fork Angular Control
Up
• Controlsare operatedcausingSolenoidA toenergize.The DCV shiftsrightaligningportsPandA.
• Pressure in applied to the piston end of the cylinder causing the forks tips to rotate up.
• Fluid from the rod end of the cylinder flows back to port B, over a filter and back to the tank.
• Once at limitof the range of motionthe pressure increasesandthe internal pilotof the pressure
relief valve opens.
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir.
Down
• Controlsare operatedcausingSolenoidBto energize.The DCV shifts left aligning ports P and B.
• Pressure in applied to the rod end of the cylinder causing the forks tips to rotate down.
• Fluidfromthe pistonendof the cylinderflowsback to port A, over a filter and back to the tank.
• Once at limitof the range of motionthe pressure increasesandthe internal pilotof the pressure
relief valve opens.
• Fluid flows through the Filter and Oil to air heat exchanger on its way back to the reservoir.
Description Make Model # Quantity
Lift Cylinder JLG 91403009 2
Tilt Cylinder JLG 91403008 1
Boom Cylinder
Texas
Hydraulics
91413152 2
Pump JLG 91413007 1
Hydraulic Control Valve JLG 91403541 3
Tank JLG 91405034 1
Hose Assembly JLG 84719469 1
Engine John Deere 91415007 1
Filter JLG 91404005 2