Lower - Toyota 7BPUE15 Service Manual

Toyota Orderpicker Model

Lower

The lower button commands the carriage to
lower. When the lower button is pressed, the
the load holding solenoid valve opens. The
proportional valve opens and allows hydraulic
fluid to return from the lift cylinders to the
reservoir.
When lower is no longer requested, the
proportional valve opens and the load holding
valve closes.
See Figure 9- 13 on page 9-44. (The electrical
schematic legend is on page 9-2.)
1. As the control handle lower switch is
closed, a digital ground is applied to
JPC 13-7 on the carriage manager.
2. The carriage manager sends a lower
command message to the steer/tractor
manager over the transmit/receive lines.
9- 1 1.
Figure
00700-CL222-05, 1 5
Service Manual
on Steer/Tractor Controller
2005
March
Section
3. The steer/tractor manager provides the
negative potential for the lift/lower
proportional valve coil a t JPT12-8,
indicated by the load holding solenoid LED
Figure 9- 1 1 on page 9-4 1. The lift/lower
proportional valve ramps closed (this valve
is normally open).
4. The steer/tractor manager provides the
negative potential for the load holding
valve coil a t JPT12-9, indicated by the load
holding solenoid LED (IL6-9). See
Figure 9- 1 1 on page 9-4 1. The coil
energizes and the load holding valve
opens.
5. The steer/tractor manager varies the
negative potential for the lift/lower
proportional valve coil a t JPT12-8,
indicated by the load holding solenoid
LED. The lift/lower proportional valve
gradually opens allowing hydraulic fluid to
return to the reservoir. See Figure 9-12.
9.
Theory of Operation