Single Clutch
The engagement of the clutch is by a diaphragm spring load, disengagement is effected when the clutch release bearing moves the spring fingers towards the flywheel. The clutch disc is positioned between the flywheel face and the clutch pressure plate and normally carries a torsion damper, these clutches are normally used on tractors in the range of 15 to 100 HP.
The steel housing is normally pressed steel, cast iron pressure plate which is used with sintered friction materials is very tolerant of operating temperatures up to 600 degrees C which can be evident with intermittent overload conditions.
Single Clutch with Independent Drive for PTO
The construction is as per a single clutch , but when an independent PTP drive is required this is facilitated by a splined hub inside the cover assembly which engages with a hollow shaft passing through the transmission, in this way the PTO drive is being driven whenever the engine is running and independent of the clutch operation. These clutches are in common use in tractors in the power range of 15 to 100 HP.
Double Clutch
This arrangement provides two independently actuated clutches with one unit, the primary clutch is for the wheel drive, and the secondary clutch for the PTO drive. The engagement load for both clutches is provided by a single diaphragm spring located between the wheel drive and PTP pressure plates. Both clutches are normally engaged and only disengaged when the driver operates the clutch pedal or a separate PTO lever. Two types of the clutch are used as follows:This arrangement provides two independently actuated clutches with one unit, the primary clutch is for the wheel drive, and the secondary clutch for the PTO drive.
The Independently Operated: here clutch engagement and disengagement are independent effected through two separate clutch release bearing mechanisms.
Sequentially Operated: in this design only one clutch release bearing is used, which during operation disengages the wheel drive clutch first and if required further depression of the clutch pedal will then disengage the PTO clutch second. Release of the clutch pedal will PTO clutch first followed by the wheel drive clutch.
These clutches are used in tractors in the power range 15 to 100 HP with a two shaft transmission.
Double Clutch with PTO Safety
Two independently actuated clutches within one unit. The diaphragm spring provides the engagement load for the wheel drive clutch only which is disengaged in the same way as a double clutch. In the safety PTO clutch, the PTO clutch is normally disengaged and is activated by the driver operating the engagement lever which moves the PTO engagement bearing forward which through the clutch engagement levers, provides the engagement load which transmits the torque through the PTO clutch disc. The term Safety is used because the PTO clutch is normally disengaged at engine start up, in the event of a mechanical failure of the clutch linkage, the PTO clutch will always immediately disengage automatically.
