Labrie Automizer Versa Hand, Maintenance Manual

Page: 163 / 190

Troubleshooting 155
Tailgate Locking Mechanism
N
OTE
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Refer to the main hydraulic schematic.
The tailgate locking mechanism is equipped with hydraulic safety systems that prevent accidental
unlocking of the tailgate during operation. One of the safety systems is the velocity fuse with the
power bleed feature; the other is the holding valve.
The spool inside the tailgate section of the valve is designed in such a way as to allow pressure to pass
through it every time pressure is building up in the hydraulic system (that is when the packer is
working). The pressure “burst” goes to the holding valve into port D1 and then out to the cylinder by
port U1 (see Figure 8-9). This will keep the tailgate cylinders pressurized and the tailgate closed
when packing material.
The velocity fuse, located on the right-hand side of the valve, will make sure to drain any slow moving
oil coming from the piston side of the tailgate cylinders. Since the rod side is being pressurized with
the “power bleed” system, the other side has to drain to avoid any pressure build-up. The velocity fuse
makes the piston side open to tank when the oil is moving under 3
gallons per minute, and will shut
close when a flow signal is sent.
Figure 8-8 Velocity fuse