"power and free" overhead conveyor
max. 8 182 kg, 4" - 6" Dearborn Mid-West Conveyor

A power and free (P&F) conveyor consists of a continuously-moving powered chain, which when engaged, moves a free (non-powered) load-carrying trolley through the conveyor system. The powered chains are typically drop-forged rivetless - link type (such as X-458 or X-678).

In a P&F conveyor system, force is applied to the free load-carrying trolley via a retractable dog, which is integral to the front free trolley. This retractable dog engages a dog which is integral to the power chain. Power is then transmitted to the free trolley. The retractable dog on the free trolley can be engaged and disengaged through the use of a blade-type stop mechanism, or by the mechanical reaction of the load carrying trolley accumulating on a trailing trolley in the free track.

A typical carrier arrangement is supported by two or more free trolleys using pivoting, load-bearing king pins. The trolley that leads is the front (accumulation) trolley. The rear or trailing trolley is equipped with a ramp or beaver tail that provides the means to begin the accumulation process.

P&F conveyors offer one performance characteristic that sets them apart from the overhead trolley conveyor family, i.e., built-in flexibility. This feature allows them to accomplish the following functions within the same system without impacting simultaenous operations occurring in other areas of the conveyor system:

Move product through production areas on specific job centers.
Stop in place for load and unload operations.
Accumulate loaded and empty carriers for high-density storage.
Speed changes as required to maintain a specific production rate or to create buffer zones.