John Deere stx38 - Manual (Page 184)

5 - 20
3/21/97
THEORY OF OPERATION POWER TRAIN
THEORY OF OPERATION
CLUTCH PEDAL AND BELT
TRACTION DRIVE SYSTEM
OPERATION STX30 & STX38
(SN —210000)
Function:
The function of this system is to transfer power from
the engine to the transaxle. This system also allows the
power transfer to be interrupted in order to stop in gear,
change to a different gear or direction, engage power
again, or shift to neutral and push the unit with the
engine on or off.
Major Components:
• Engine drive sheave
• Drive belt
• Clutch pedal and shaft
• Actuating spring assembly
• Bellcrank assembly
• Transaxle drive sheave
Theory of Operation:
As the clutch pedal (A) is depressed, the clutch shaft
pulls the clutch actuating spring (B) assembly forward.
Initial movement of the pedal compresses the spring in
the actuating assembly and once compressed
transfers the movement to the bellcrank (C). As the
bellcrank (C) is rotated, drive belt (D) tension is
released. This allows the engine drive sheave (E) to
rotate without transferring power to the belt (D) due to
slack in the drive belt. As the bellcrank (C) is rotated,
the belt tension spring (F) is stretched.
M42156
A
C D
B
E
F