Whiting springs and balancers

We offer made to measure Whiting springs and balancers. In order to appreciate the value of ‘’made to measure’’, we present the following facts and will try to disperse some fallacies. 

The role of the balancer

The role of the balancer is to absorb most of the door’s weight, so that the operator may not have to exert a strength exceeding say 5 lbs (2.3 kgs) to lift or lower the door along its entire height.

How does it work?

The Whiting balancer is made up of a fixed shaft (it does not turn) and two spring assemblies with drums towards the walls for the cables to roll onto. Each spring thus absorbs half of the door’s weight.

Let us assume for a moment that the springs of the balancer are well calibrated for the door’s specific dimensions and weight.

In the full-open position, there is little tension on the cables and springs, essentially what it takes for the door to remain open. As we lower the door, the cables unroll from the drum, add turns to the springs and increase its tension: the force required from the operator to lower the doors remains the same. The reverse force required to lift the door also remains the same along the full course.

All spring assemblies are not equal

There are two types of Whiting spring assemblies: 2376 and 7176. The coils of the 7176 spring assembly have a greater diameter (more strength) and use an aluminum drum, vs the nylon drum of the 2376. The 7176 is typically (but not limited to) used for Coldsaver doors, which are heavier.

The two types of spring assemblies can be built with several different coil diameters, reflecting the different door dimensions and weights. Three main factors determine the type of spring assembly and the coil diameter and length:

• height of the door: determines the number of cable turns around the drum
• width of the door: determines maximum spring length
• weight of the door: determines the type of spring assembly and the coil’s diameter/length

The length of the coil has a significant impact: a shorter spring is stronger. You can intuitively prove this by manually winding a spring over 60 cm and then winding the same spring over 30 cm…

A well-adapted and adjusted balancer will result in a small, constant force being required to lift and lower the door over its full height. The oft-seen and heard notion that there is a standard replacement balancer assembly for dry freight doors and a standard replacement balancer assembly for insulated doors is at best, frivolous…

How do you recognize that you have the wrong balancer?

A sure telltale sign of a balancer not calibrated for your door: the door is very heavy at the bottom, yet flies up a bit above middle height. If you need two hands to bring it down from the full-open position, you really don’t have the right balancer…

Note that a door that is evenly hard to lift and lower along its full height may only need that the rollers and hinges be repaired and lubricated, the tracks be cleaned, and possibly a balancer adjustment.

Life expectancy

A well-calibrated balancer, properly adjusted and maintained (lubricated) has a typical life expectancy of 15 000 to 25 000 openings. It is after a mechanical part and, like tires, will not last for ever. Practically speaking, a well-maintained balancer installed on a unit effecting 20 deliveries per day, 240 days a year, will typically last from 3 to 5 years before breakdown. There are of course exceptions, one way and the other.

Periodic maintenance of the balancer will maximise life expectancy. On the other hand, an overtaxed balancer (as in the foregoing example) will break sooner than later.

Costs

A made-to-measure balancer is no more expensive that an off-the-shelf balancer, but will offer a better overall performance and will last longer.