Hard working excavators, tunnel boring, mining, oil field and forestry equipment use a variety of tool attachments. This allows them to be versatile for a multitude of activities, all necessary to perform the work at hand. Some of these attachments require multiple connections to the hydraulic lines, depending on their individual function, whether it be digging, scraping, scooping, grabbing and lifting, cutting, or any other articulated motion.
At the job site, equipment tool attachments might be changed out several times in the process it takes to complete the project. A machine operator can save time and efficiently utilize a single piece of equipment by switching out a bucket for a scraping blade or rock crushing hammer or any other attachment end that is needed.
Heavy-duty screw-to-connect quick couplings are the best choice for these types of tool attachment connections. They allow the hydraulic lines between the equipment and the tool attachment to be quickly disconnected and reconnected without extensive downtime.
Screw-to-connect couplings are built to withstand the demanding requirements of applications where hydraulic lines are subjected to the stress of high-pressure impulses. The repeated pounding of pressure in the lines and through the coupling can wreak havoc and easily cause damage to the internal components and sleeve locking mechanism of any standard quick coupling.
The threaded sleeve on a screw-to-connect coupling provides a secure connection that is resistant to loosening or disconnection caused by vibration. It is also a good defense from the damaging effects of material Brinelling, which results from hydraulic shock when repeated pressure impulses cause the metal to deform. When Brinelling occurs on a quick coupling with a standard sleeve mechanism, the coupling can become permanently locked together and inoperable. Threaded sleeves on screw-to-connect couplings prevent Brinelling and keep couplings in working order to be reliable for repeated connection and disconnection.
Parker understands the rigorous performance expectations that define screw-to-connect quick couplings. The FET and 59 Series have both been engineered to meet the challenge. Built from high strength materials, these couplings are rated for pressures up to 6,000 psi. They also enable connection while hydraulic lines are under residual pressures up to 5,000 psi and disconnection at 2,500 psi. The ability to connect the couplings while under pressure allows equipment operators to switch-out tool attachments without first having to spend time bleeding pressure off the system.
Parker FET and 59 Series also have flush face valves that are designed for non-spill operation, virtually eliminating fluid loss at disconnection and featuring low air inclusion at the connection. Air inclusion in a hydraulic system causes diminished performance and increased wear of system components. Non-spill valves guard against the damaging pressure checking from trapped air in the lines.
As the FET and 59 Series have many similarities, they also have some significant differences that are important considerations when choosing the best screw-to-connect coupling for your heavy-duty application.
Parker’s FET Series is directly interchangeable with other manufacturers’ screw-to-connect couplings of similar design. The threaded sleeve uses the same style of connecting threads as the competitive designs, which can take up to seven sleeve rotations to complete a full connection of the two coupling halves. This is a very popular and widely used interchange design. FET Series Couplings have an FNC coating and stainless steel valves for extended durability and corrosion resistance. They are available in a wide range of body sizes up to 2 inches. Heavy-duty Code 62 Flange ends are also an option for the larger sizes.
Parker’s 59 Series is highly engineered with the end-user in mind. This unique screw-to-connect coupling makes the most demanding hydraulic connections manageable. Rugged Acme threads in the connecting sleeve resist damage, and the larger thread form is easier to keep clean from dirt and debris. The double start feature quickly aligns the threads to provide fast engagement and a full connection requires only 2.5 sleeve rotations. The 59 Series also has an integrated bearing that adds a swivel function to ease the frustration of dealing with hoses under pressure.
The FET Series is ideal for any high impulse screw-to-connect application, especially where couplings need to be interchangeable with other similar couplings already installed on equipment in use. In contrast, Parker’s 59 Series has a unique design and brings the benefits of added performance features to provide a faster, cleaner and easier connection that far exceeds other heavy-duty screw-to-connect couplings available today.
Learn more about Parker’s screw-to-connect solutions.
Article contributed by Lori Wessels, product sales manager, Quick Coupling Division, Parker Hannifin Corporation.