By Josh Cosford, Contributing Editor
If you’ve spent any reasonable amount of time working on or around mobile machinery, you’re very familiar with PTO-driven machinery, including the hydraulic pump. The PTO shaft exiting the rear of a farm tractor is used to power mechanical implements through a drive shaft, such as bailers or mowers, themselves sometimes attached to the tractor itself via a 3-point hitch. Pumps are also mounted to the PTO shaft, providing an easy source of hydraulic energy in addition to the tractor’s secondary hydraulic outputs.
For on-road machineries, such as stone slingers, dump trucks or fire engines, no such external drive shaft is used. Instead, the transmission of the vehicle has a removable panel where a power take-off is mounted to provide a drive shaft or pad mount for pumps or other purposes. A hydraulic pump, for example, mounts either directly or closely to the PTO unit, supplying hydraulic energy for various machine functions.
What both tractor and on-road PTO options require is a drive shaft terminating at the pump, eliminating any other purpose or potential for driving mechanical functions. Although options like a split shaft take-off or PTOs with multiple take-offs do exist, they’re expensive and bulky. As well, the location of the PTO drive is previously limited to under the truck or behind the tractor. A great new concept in the world of machine drives is the PTO through-drive motor.
A PTO through-drive motor allows the unique ability to mount the drive system anywhere your creativity conceives, so long as it’s run via a hydraulic pump elsewhere. Imagine mounting a drive shaft for a pond pump mounted at the end of an excavator’s arm? Or being able to mount a PTO driven implement to the back of your skid steer loader, powered by auxiliary hydraulics?
Linde offers such an animal, if you were doubting its existence, available as their HMV/R-02 series PTO motor. Essentially, it’ a through-drive motor with splined joints at either end allowing the attachment of various sizes of PTO shafts. Provided are two opposed shafts allowing it to fit in the driveline of existing equipment, so hydraulics can now power machinery previously only brought to life mechanically.
Just as with the standard HMV-02 series of motors from Linde, displacements are available all the way up to 331 cc/rev, and with up to 500 bar (7,250 psi), peak torque is well over 2,200 Nm (1,628 lb-ft), twisting with enough force to power most PTO driven machinery on the market. The Linde system works with five standard shaft sizes, each running ANSI B92.1 splined outputs.