more arresting engine and retractable sheave is bypassed, the deckedge indicator light will display the green and amber lights. SEQUENCE OF OPERATION Energizing the motor to raise the retractable sheave, by pressing the RAISE push button, causes the motor to rotate a helical gear keyed to its shaft. This transmits the motor force to another helical gear on the wormshaft. The wormshaft turns the worm and drives the worm gear on the sleeve. The worm gear rotates freely on the sleeve for part of the rotation, thus permitting the motor to gain speed before full loading. As the worm gear rotates, the lugs on its face engage the lugs on the face of the clutch bevel gear. Rotation of the clutch bevel gear, which is splined to the sleeve, rotates the sleeve, which is directly connected to the screw of the retractable sheave, thus raising the sheave. When the sleeve rotates, the limit bevel gear, keyed to the sleeve, rotates to turn the pinion of the geared limit switch. This is the only function of the limit bevel gear.    When a predetermined point is reached by the rotor of the geared limit switch, the RAISE circuit is broken and the raising operation ceases. As the geared limit switch is actuated, the green lamp (sheave UP lamp) will light in the deckedge light box. Energizing the motor to lower the retractable sheave, by depressing the LOWER push button, causes the motor and the drive system to operate in the reverse direction. Again there is free rotation until the lugs on the worm gear make a complete revolution before striking the other side of the lugs on the clutch bevel gear. The sheave lowers until it is completely seated and opens the torque limit switch to break the motor circuit. If an obstruction prevents the sheave from descending, the worm, which is still rotating because of the force of the motor, does not turn the worm gear. The worm is driven axially along the wormshaft until the torque limit switch is opened by the tripping plate washer. The torque limit switch may be adjusted to permit the sheave to seal with a predetermined force before the circuit is interrupted. The torque spring then absorbs the remaining inertia of the system after the circuit is broken. During the time the sheave is lowered and raised up until the time the RAISE geared limit switch is tripped, the red (sheave NOT UP) lamp glows on the deckedge light box. For manual operation, the handwheel must be mounted on its shaft and secured to the shaft with a setscrew. The declutch lever must then be thrown in a counterclockwise direction. This movement will slide the clutch bevel gear along the splined section of the sleeve to engage a gear on the handcrank shaft. When the handcrank is turned, the sleeve turns, rotating the sheave screw to raise or lower the sheave. The declutch lever remains in the clutch position until operation under motor power is resumed, at which time the handwheel is disconnected automatically by the clutch trippers. There is no danger to an operator if he or she is turning the handwheel when the motor is started, because the handwheel is disengaged instantly without shock or jolt. The following are instructions for removing parts in order to gain access to the unit when it needs servicing or inspecting: 1. Shut off the power. 2. Remove the limit switch cover. 3. Disconnect the power and control wires from the operating unit. 4. Remove the entire operating unit from the mounting pad. 5. Remove the electric motor. 6. Remove the mounting screws and take out the geared limit switch. 7. Remove the pipe flange (end opposite mounting pad), and take out the gland thrust ring. 8. Remove the housing cover from the end opposite the mounting pad. Remove the gland follower and packing cover. 9. Remove the lubricant from the housing. 10. Loosen the setscrew in the declutch lever hub and remove the declutch lever. 11. Remove the three capscrews from the handwheel through the cap and pull out the entire handwheel pinion assembly. 12. Loosen the jamnut and setscrew in the clutch fork and remove the declutch lever. 3-31