The instant an overload occurs, the pressure of the drive and

reset springs is overcome by the extra force applied to them.

The drive pawl is forced out of its engaged position from the

rotor and as it pivots up, the reset pawl lifts and locks it out of

contact with the rotor as shown in Figure 2. The clutch then

rotates freely.

When the overload condition has been corrected, the clutch

is reset by inserting a hexagon wrench in the reset screw

and turning the screw clockwise until the reset pawl releases

the drive pawl. When the drive pawl re-engages with the

rotor, the reset screw must be backed out to its original stop

position. This is essential to restore the torque to its original

setting.

Fully Automatic or Semi-Automatic

The instant an overload occurs, the pressure of the drive and

reset springs is overcome by the extra force applied to them.

The drive pawl is forced out of its engaged position from the

rotor. After one revolution the drive pawl will automatically

return to its engaged position. If the overload is still present,

it will not seat and will continue to rotate until overload has

been removed. The drive should be stopped as soon as

possible. After the overload condition has been corrected the

drive must be “jogged” until the drive pawl engages with the

rotor.

Note: Models “SB” and “SP” are semi-automatic because the

actuating plate must be manually reset. See models F (page

27) or SA for fully automatic operation.

Limit Switch Pin

A Limit Switch Pin is furnished as a standard item for

model SA and SM to activate a limit switch that triggers

the electrical controls. The travel of the Limit Switch Pin

protruding radially from the clutch housing is controlled

by the drive pawl motion upon disengagement. The Limit

Switch Pin can only be effective if the housing continues to

turn when an overload occurs and the rotor stops, (i.e., the

housing is the driver and the rotor is the driven). The housing

RPM must be considered to determine the time for the Limit

Switch Pin to revolve around before contacting the limit

switch.

The standard Limit Switch Pin extension is 1-inch, however,

it can be made flush with the housing when engaged. If the

Limit Switch Pin is not required, it can be omitted from the

assembly with a “Z1” suffix.

If instantaneous operation of a limit switch is required or if

the housing stops upon overload, see Page 25 for the Limit

Switch Plate Actuator or the Model F on page 27. Units which

include this device do not have the Limit Switch Pin.

Housing

Limit Switch Pin

Retracted

Reset Spring

Drive Pawl

Engaged With

Rotor

Rotor

Drive Spring

Figure 1 – Engaged

Drive Pawl Locked

Out Of Contact

With Rotor

Limit Switch Pin

Extended

Reset Pawl

Engages Notch

in Drive Pawl

Manual

Reset Screw

Figure 2

Disengaged - Manual

Limit Switch Pin

Extended

Reset Pawl Holds

Drive Pawl In Contact

With Rotor

Drive Pawl

Disengaged From

Rotor

Figure 3

Disengaged - Automatic

Trig-O-Matic Overload Clutches ORC Series

Standard Model S

18 Boston Gear 800-825-6544 .....P-1500-BG 1/12