Vestil HYDRA-HD handleiding
Handleiding
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Copyright 2015 Vestil Manufacturing Co. Page 16 of 18
Detailed Explanation of Hydraulic System Operation:
Raising the deck:
The sequence of events begins with the foot pedal in the neutral, or “home”, position. The operator first activates
the hydraulic system by pressing the foot pedal down. This is referred to as the “power-stroke”. Next, after releasing
the foot pedal, the piston return spring (B) exerts an upward force on the piston. Consequently, oil flows from the
reservoir, through the inlet check valve, and into chamber A. At the same time, oil trapped in chamber B (from a prior
cycle) flows across the back-fill check into chamber A. When another power stroke occurs, the inlet check valve
closes, which prevents oil from flowing back into the reservoir; simultaneously, the outlet check valve opens and oil
flows into the cylinder. In preparation for the next stroke, the piston return spring forces the piston and the foot pedal
back to the home position. Chamber A again fills with oil as the piston rises.
The pump piston has two modes of operation: 1) Low-pressure, high-volume; and 2) High-pressure, low-volume.
1. Low-pressure, High-volume.
When raising an unloaded or lightly loaded platform, the piston will function in low-pressure mode. As the
operator presses the foot pedal (power stroke):
a. Back-fill check remains closed;
b. High / low volume relief poppet remains closed; and
c. All oil in chamber A flows into the cylinder.
2. High-pressure, low-volume
When raising a partly loaded or heavily loaded platform, the piston will function in high-pressure mode. As the
operator executes a power stroke:
a. Back-check remains closed;
b. High / low volume relief poppet opens;
c.
A volume of oil equal to the annulus (piston diameter minus the rod diameter) flows from A to B;
d. Oil equal to the cross-sectional area of the rod flows to the cylinder; and
e. The opening force of the high / low volume relief poppet adds to the cylinder load resistance.
Pressure relief system
If a load that exceeds the maximum rated load is placed on the deck, or a mechanical malfunction interferes with
the movement of the deck, the pressure relief valve will open during a power-stroke. The pressure relief valve reduces
the likelihood that excessive loads will damage the lifter frame or the hydraulic system. The pressure relief valve
shunts oil directly from chamber A to the reservoir.
Release valve assembly
The foot-actuated release valve assembly is the mechanism that allows the deck to lower. When the release pedal
is pressed down, the release valve opens, and oil flows from the cylinder to the reservoir. The lowering rate is
adjustable; instructions appear under “Release pedal adjustment” on p. 11. Lowering rate is also variable: the farther
down the release pedal is pressed, the more rapidly the deck descends. The weight of a load on the deck affects the
flow rate, and therefore, a heavier load will lower more rapidly than a lighter load, regardless of the lowering rate
selected. When the operator lets the pedal loose, the release pedal tensioning spring returns the release pedal to the
home position, which automatically closes the valve.
Bekijk gratis de handleiding van Vestil HYDRA-HD, stel vragen en lees de antwoorden op veelvoorkomende problemen, of gebruik onze assistent om sneller informatie in de handleiding te vinden of uitleg te krijgen over specifieke functies.
Productinformatie
| Merk | Vestil |
| Model | HYDRA-HD |
| Categorie | Niet gecategoriseerd |
| Taal | Nederlands |
| Grootte | 10426 MB |
