LiftMaster Model J Drive Components - DDM Garage Doors Blog

Posted November 6th, 2020 at 6:46 pm by Dan Musick

One of the more common LiftMaster Operators is the jackshaft operator. How does the torque get from the motor to the counterbalance shaft of the sectional overhead type door? In this video, we trace the torque as it moves through the LiftMaster Model J drive components.

In this video, you can see how the mechanical drive components of a LiftMaster Model J operator work.

The torque power begins with the motor drive shaft. Secured to this is the small pulley which moves the v-belt. This belt transfers torque to the clutch pulley, which is secured to the clutch shaft with only pressure plates to allow for slippage. The shaft goes through the operator frame to the other side where it’s held in place with washers and a ring clip.

Inside the operator frame is a series of sprockets and chains to reduce the operator speed and increase the torque. This transfers torque from the lower clutch shaft to the upper drive shaft.

The driveshaft goes through the operator frame to the other side, where a sprocket is secured to the shaft. As the sprocket turns, the drive chain turns the torsion shaft sprocket which is secured to the shaft. This in turn opens and closes the door when the motor is running.

LiftMaster Model J Operator

If you need assistance with installing a jackshaft operator, please watch our YouTube video titled, “How to Install LiftMaster Jackshaft Operators.”

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