SMB/SB Installation and Maintenance Manual 140-11000 • July 2003
5.2 Manual Operation
In the event of a power failure, the actuator can be operated by hand using the handwheel. The actuator has an automatic handwheel
declutching arrangement. For manual operation, the declutch lever is pulled downward. This mechanically disconnects the electric
motor from the handwheel through the clutch assembly.
SMB-000 and SMB-00
Piece numbers refer to Figures 7.1 to 7.3 and 7.4 to 7.8.
For the SMB-000 and the SMB-00, the Clutch Ring (piece #33) and the Clutch Keys (piece #23) are moved upward until the Clutch
Keys engage with the lugs on the bottom of the Handwheel (piece #5). For the side-mounted Handwheel on the SMB-00, the Clutch
Keys engage the lugs on the bottom of the Bevel Gear (piece #100).
Trippers (piece #28, 29) hold the Clutch Keys in this position. The actuator will remain in hand operation indefinitely until the
electric motor is energized and the Tripper Cams (piece #27) mounted on the Worm Shaft (piece #43) cause the trippers to release the
Clutch Ring (piece #33) and the Clutch Keys (piece #23) from their hand position. This is an automatic feature of the actuator.
SMB-0 through SMB-4
Piece numbers refer to Figures 7.9 to 7.11.
The declutching action is similar to that of the smaller SMB actuators. When the Declutch Lever (piece #10) is depressed, the
Declutch Shaft (piece #24) causes the Declutch Fork (piece #12) to push the Worm Shaft Clutch Gear (piece #41) out of engagement
with the motor helical gearing and into engagement with the Handwheel Clutch Pinion (piece #42). The Clutch Trippers (piece #32,
33) lock the worm shaft clutch in this position. When the Handwheel (piece #5) is rotated, the Handwheel Gear (piece #7) turns the
Handwheel Clutch Pinion (piece #42) and the Worm Shaft (piece #43), placing the actuator into manual operation.
When the electric motor is energized, the Tripper Pins (piece #51), which are part of the Worm Shaft Clutch Gear (piece #41),
cause the Trippers to be released, allowing the Worm Shaft Clutch (piece #50) to be released from hand operation and engage in
motor operation.
For all actuator sizes, when the handwheel is turned, the motor does not rotate; and when the motor is in operation, the handwheel
does not rotate in manual operation.
SMB-5 through SMB-5T
Piece numbers refer to Figures 7.13 to 7.16.
The declutching action is similar to that of the smaller SMB-0 through 4 actuators. When the Declutch Lever (piece #9) is
depressed, the rotation of the Declutch Shaft (piece #30) causes the Declutch Fork (piece #14) to push the Sliding Gear Clutch (piece
#51) out of engagement with the Flexible Jaw Clutch Housing (piece #50) and into engagement with the Handwheel Gear (piece #6).
The Clutch Trippers (piece # 33, 34) lock the Drive Shaft Clutch in this position. When the Handwheel (piece #5) is rotated, the
Handwheel Shaft and Pinion (piece #40) turns the Handwheel Gear (piece #6) and the Hollow Drive Shaft (piece #55), placing the
actuator into manual operation.
When the electric motor is energized, the Motor Clutch Gear Cam Pins (piece #52), which are part of the Flexible Jaw Clutch
Housing (piece #50), causes the Clutch Trippers (piece #33, 34) to be released, allowing the Sliding Gear Clutch to be released from
hand operation and engage in motor operation.
For all actuator sizes, when the handwheel is turned, the motor does not rotate; and when the motor is in operation, the handwheel
does not rotate.
5-2
Flow Control Division
Limitorque Actuation Systems
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