Pattern Changer Valve – Holmbury Inc.

Holmbury’s OCUKAC2318 is a high quality  pattern changing valve with a steel body and hardened spool for pilot applications, such as switching between John Deere and Cat control patterns on excavators.



Pattern Changer Valve

I recently installed one of these valves on a Caterpillar 321B excavator. Right out of the box, its ready to go. On this installation however, I decided to modify the spool and make a spool extension, so the handle would come up through the 1/2″ floor plate. This allowed utilizing all of the existing pilot lines without modification, and the addition of four 3′ pilot lines.




Extending the spool length and mounting the handle on the extended side allowed for flush mounting the valve on the underside of the floor plate. To modify the spool, a hole was drilled and tapped into the spool end(it’s a little tricky as it is a hardened spool), then an extension was machined to thread in. The extension was loctited in and cross drilled parallel to the original handle hole on the other end.This put the handle at one end of the spool, while leaving the limiting stops at the other end.

Check out the pictures below.  This valve is very compact and perfect for pattern changing applications. I would definitely use it again. Check out Holmbury Inc. http://www.holmburyusa.com/