Operating Principles

The basic operating principle of an automatic swimming pool cover is not much unlike an overhead garage door. In fact, some of the earlier models had large spring tensioning systems that helped the gear motors in their travels as well as acting as a cushioning or shock-absorbing device in the event of any obstructions.

Pulling the pool cover off the swimming pool is accomplished by the turning of a spindle or drum which the cover wraps-up on, while pulling the pool cover over the swimming pool is accomplished by the turning of a set of reels which the pool cover ropes wrap-up on.

 

There are two basic powertrains for an automatic pool cover system, the first being an electric gear motor driven and the second being a hydraulic pressure driven.

 

Electric gear motor driven - This type of unit is driven by any number of brands and sizes of electric gear motors (suited for the size and configuration of the pool cover) placed at the drive end of the mechanism. The gear motor turns in the direction of desired cover travel. Switching of travel direction is accomplished by a simple set of reversed single-dog gears and a double-dog gear. Adjustable torque-limiting devices are used to limit stress on the system at the ends of the covers travel as well as acting as stop sensors. The electric motors being used by todays manufacturers are designed especially for this application and are completely submersible, so water damaged motors are a thing of the past.

 

Hydraulic pressure driven - This type of unit is operated by hydraulic pressure generated by a hydraulic pump, which is generally located at the pool equipment pad. The hydraulic pressure (between 600 and 800 psi.) is supplied by two hydraulic lines from the hydraulic pump to the hydraulic motor or motors at the drive end of the mechanism. With a single hydraulic motor application the same double-dog gearing system as in the electric unit is used to switch direction of travel. With a dual-motor application a manifold is used to switch direction of travel. Adjustable pressure relief-valves are used to limit stress on the system at the ends of the covers travel as well as acting as stop sensors.