hydraulic valve

[6sunset6]

I was looking at a big chipper the local tree guy has. There is a winch option added that has the hydraulic motor sliding back and forth with a mechanical face dog clutch to engage. When the winch cable is off at an angle the frame had enough torque on it so the face dogs pop apart . The guys were really complaining about it.I took a look. The chipper hydraulics look good. Electrical switches running Vickers valves on a manifold. The reason for the face clutch is to allow free wheel.
With out changing anything on the valve bank I think the problem can be fixed with a double selector valve.
Assuming the hydraulic motor will free wheel if the motor supply lines are are connected open. Test this first by removing supply lines from the motor, engage face clutch and see if the winch cable can be pulled out. IF not A motor change might work. I have not looked at that. IF it does free wheel the I think a two position detented double selector valve would work.
The valve really wants a spool that in one position feeds the motor normally. In the other position the motor output is connected to input. The input line is connected to the return line. No changes to any other hydraulic controls on the machine. The face clutch would be replaced by a lovejoy coupling and the hydraulic motor bolted in the engaged position.
I have not been able to find a selector valve with a spool like this. The standard Prince selector valve I think would work if plumbed backwards. Ports C and D plumbed to the motor. A and E with a jumper hose across them. B and F supply lines. Anybody have an opinion on this?

 

[J_J]

What is it you want the motor to do in the neutral position. Allow the winch cable to be pulled?

A motor spool valve will run the motor in both directions, and free wheel in neutral.

An open center valve will also let the motor free as all ports are common. to tank.

If you wanted to lock the spool then an open center cyl spool would work, and to prevent the pump from trying to work as a motor, a double relief valve across the motor is requires.

Would this valve work for you?

Surplus Center - 1 SPOOL 8 GPM PRINCE MB11C5C1 MOTOR SPOOL VALVE

Could you also install a high pressure hyd gate valve or solenoid on/off valve across the input and output, lines, and then if you can pull the cable, the fluid would just recirculate with in the hyd motor.