SUPER MAJOR SUPPLEMENT HYDRAULIC POWER LIFT GENERAL DESCRIPTIONThe hydraulic power lift fitted to the Fordson Super Major offers a choice of operating
control enabling either Qualitrol (constant draft) or Position
Control (constant depth or height) to be selected according to the work being undertaken and the
ground conditions encountered.
An auxiliary control plate is fitted as standard equipment to facilitate operation of remote rams and incorporated in the auxiliary plate assembly is a flow
control device enabling the rate of hydraulic work to be adjusted irrespective of engine speed.
" Live " hydraulics are automatically available when a '' Live " power take-off (optional equipment) is fitted, and gives the advantage that the
tractor may
be stopped or
gear changes carried out without affecting the operation of the hydraulic system.
Hydraulic Lift Linkage
With the introduction of the new hydraulic system for the Fordson Super Major the layout of the rear linkage has been modified and it is no longer necessary to use the two position lower links to improve weight transference under arduous conditions.
This option will, however, continue to be supplied through service for previous production tractors.
The new linkage is readily convertible to suit either Category 1 or Category 2 implements, the necessary conversion parts being supplied as standard equipment with all Super Major tractors.
The lower a link end swivel balls are removable and the Category 2 balls fitted to the lower links during production can be replaced by the smaller pair supplied with the I tractor.
Similarly, the
top link can be fitted with an alternative rear end piece, again the Category 2 end being fitted in production and the alternative Category 1 part being supplied with the tractor.
A heavy duty check chain
bracket is now fitted as standard to all Super Major Tractors, either heavy duty or standard check chains being fitted as requested and the lower links being drilled to take either chain.
The check chain shackles incorporate two holes to allow the lift arms to be swung closer or further apart according to the different size of implement in use. Only heavy duty check chain brackets, with either single or double holes, will be supplied in service and can be used for replacement of all previous brackets including heavy duty and standard single hole and heavy duty and standard two position brackets.
When replacing a previous type standard bracket (three
bolt fixing) with a
current heavy duty bracket (four bolt fixing) it will not be necessary to fit
the extra bolt.
The automatic
clutch release previously used is not suitable for current production tractors mainly due to the changes to the top link pivot bracket.
A new installation has been released for use with the new hydraulic system and details of this will be issued as separate information.
This unit is normally only used under arduous conditions and has therefore only been released with Category 2 ball ends in the top link.
Top
Cover Assembly
Oil is fed, under
pressure from the pump, via a feed pipe to a flange at the top of the
transmission casing and from here into drillings in the top cover assembly.
The top cover acts as a
housing for the control linkage and has attached to it the lift cylinder assembly which acts as a combination of
valve chest and ram
cylinder housing, and also the auxiliary service and
flow control plate assembly.
Fitted in the top cover is a
check valve, the purpose of which is to stop the return of oil from the
ram cylinder when the implement is in the transport
position, and also a pressure
relief valve which protects the hydraulic system from damage should an attempt be made to lift an excessive load.
Flow Control DeviceUnder certain conditions of operation it is preferable to be able to control the rate of flow of oil to the ram cylinder or auxiliaries.
When ploughing for instance, only a slow oil feed is required, whereas when using auxiliary equipment such as front end loaders a fast rate is sometimes required.
On the Super Major a flow control device is incorporated in the auxiliary service plate assembly which allows such control to be applied.
Incorporated in the control unit is a
restrictor which locates in the main feed from the pump thus when the control
knob is screwed '' out" the control unit and hence the restrictor is rotated and greater
restriction is applied to the flow of oil, and vice versa.
The limiting position either way is indicated by the marking '' F " (fast or maximum flow) and " S " (slow or minimum flow) on the auxiliary control housing.
The pump side of the restrictor is connected to the front face of a control valve whilst a branch drilling on the lift (or auxiliary service) side connects with the rear face of the valve.
Oil passing the flow control valve restrictor experiences a slight pressure drop duz to the restriction to flow, therefore oil at full pressure is fed to the front face of the flow control valve
plunger and oil at reduced pressure to the rear face of the plunger.
If the pressure difference is sufficient to overcome the pressure of the flow control valve
spring, the plunger will move and allow oil from the high pressure side of the restrictor to bleed-off into the transmission.
The amount of oil which is bled-off will depend on the pressure difference between the two faces of the flow control valve plunger, this difference being in direct relation to the position of the flow control valve restrictor.
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