Whether off-highway equipment is used in construction, agriculture, mining, or whatever, a continuing trend is versatility. Machines that can perform multiple tasks can be greater utilized to shorten the return on investment of the machine. For example, an excavator that was acquired for digging and loading can increase its value if it can break concrete or use a grapple to transfer scrap when it’s not needed for digging.
To do this, the excavator or other machine needs quick-acting couplings to allow quick-and-easy changing from one tool to another. To eliminate an operator from having to physically connect or disconnect multiple hydraulic lines, multiple couplings can be grouped into a manifold so that all hydraulic lines can be connected or disconnected all at once. Electrical lines can even be incorporated into the manifold so that all connections to an implement can be made at once. Even the simplest attachments have a supply and return line, and more complex attachments may have eight or more hydraulic lines.
The manifolds can also be used with special-purpose machines, such as a road paver. These machines perform multiple tasks at once, but they are not designed to do anything else. Still, a coupling group for specific implements can drastically speed maintenance if a failure occurs. Instead of having to disconnect multiple lines to replace an implement, the process can be done in one quick, easy step by using multiple couplings manifolded together.
The key to success However, a manifold must be designed with quick-acting couplings suited for the application. Matt Mulder, vice president of Faster Inc., Maumee, Ohio, suggests that no-spill, flat-face couplings are ideal for mobile equipment because of their cleanliness and leak free operation. Oil spills attract and accumulate dirt, so using couplings that don’t leak during connection and disconnection not only keeps equipment and environments cleaner, but also reduces the potential for dirt to find its way into the hydraulic system.
Mulder explains that quick-acting couplings for mobile equipment must accommodate the pressure, flow, temperature, potentially corrosive environments, and specific type of hydraulic fluid encountered in these demanding applications. They must also be rugged enough to tolerate impacts, shock, and vibration often encountered at work sites.
Pressure can be especially critical because of the rapid increases in pressure that can occur when a tool hits an immovable object like a large rock. When breakers or similar devices are used, pressure may undergo rapid pressure pulsations inherent to these tools. And even though the coupling is rated to accommodate normal system pressures, these pressure spikes can cause fluid to slowly seep, or “weep,” out of the hydraulic system.