Operation 3 - Relief Valve; Operation 4 - Hose Burst Condition - jcb 214e Service Manual

Backhoe loader

Hide thumbs Also See for 214e:

Table of Contents

www.WorkshopManuals.co.uk

Hose Burst Protection Valve

Boom & Dipper Operation (Cont'd)

Operation 3 - Relief Valve

If during normal operation the pressure in the rod side of the

dipper ram increases (for example, by the operation of the

bucket against an obstacle), increasing pressure in the ram

enters at port Y. The position of spool F prevents this

increasing pressure from venting back to the tank. The

pressure increases to such a point that it moves plunger K

off its seat (to the right) against the force of spring L.

The new position of plunger K opens a connection to cavity

J, the pressure is high enough to move spool F to the left

against the force of spring H. The new position of the spool

creates a connection from the rod side of the ram to port B.

Note that oil exhausted via port B will not reduce to low

pressure until the A.R.V. in the excavator valve block also

If a burst hose or other leakage occurs in the feed to the rod

(raise) side of the ram, check valve C will be kept firmly held

on its seat by the back pressure generated due to the weight

the load in the bucket and the force of spring

Oil trapped between the valve and the ram will prevent

movement of the load. To lower the load, see Lowering The

Circuit Descriptions

Purchased from www.WorkshopManuals.co.uk

BACKHOE VALVE

Component Key:

4cx 3cx 214 215 217