Extension Springs vs. Torsion Springs
There are two types of spring systems commonly used
on sectional garage doors.
Extension springs
Sometimes referred to as stretch springs function
much as their name indicates; as the door travels down, the springs stretch
out parallel to the horizontal track increasing the counterbalance force
as more of the weight of the door moves from the horizontal track to the
vertical position. With proper spring selection the counterbalancing of
the spring will match the weight of the door so that the door will “balance”.
Torsion springs
Achieve this counterbalance with springs that wind
up as the door travels down. The amount of “tension” that is generated
is the result of a number of factors that include the size of the spring
wire, the length of the coil, and the diameter of the coil. Other factors
in spring selection include the weight of the door, the diameter of the
drums and the radius of the track (the curved part between the horizontal
and the vertical track), and how much the spring is wound up.
Proper selection of torsion springs is not a matter of happenstance, but
requires careful calculation. Just remember that you can’t just put any
spring up and expect to balance it by simply adjusting the number of turns
(how much the spring is wound up). Torsion springs are mounted on a bar
or shaft usually across the top of the door, (when the door is in the
closed position), as pictured in our home page.
There are a number of advantages to the torsion system
over the extension systems. Because the torsion springs lift the door
by turning a shaft that turns the cable drums, both sides of the door
are lifted simultaneously. This makes for smooth operation which in turn
helps a door system to wear less and last longer. Lifting the door smoothly
and evenly is particularly important on wider doors like those wide enough
for two cars to pass under. The number of turns used to balance a door
is a matter of door design. Because the cable length is taken up on the
cable drums the full length of the cable needs to be wound up with enough
extra turns to hold the door up in the open position.
Spring Breakage
All springs will eventually break from usage. The motion
of stretching on extension springs or coiling up and uncoiling on torsion
springs causes metal fatigue which will result in a break. It is the same
principle as bending a coat hanger back and forth until it breaks. The
significant difference here is that spring steel can be bent back and
forth many more times before it fatigues.
Are you ready to replace your broken spring?
Call us,
we might be able to have your door fixed today!
Highlife Springs
Years ago it was common that garage doors were used
only a few times a day for the car to go out in the morning and back in
at night. Peoples habits have changed. We seldom walk anywhere and we
use our cars to come and go. The garage door gets used more than the front
door.
With multiple car families, the use of double wide
garage doors, remote controlled operators, both husband and wife working
and kids coming home from school and letting themselves in through the
garage door via a digital entry system or key switch, it’s easy to see
how garage door use has doubled many times over. With the increased use,
springs are cycled more and logically don’t last as long. That’s why we
offer highlife springs.
Longer life springs can be made
in a variety of ways including the use of a higher quality of wire such
as “piano wire”. This however, is not cost effective as the wire costs
too much.
The most common way to provide highlife springs is
to increase the wire diameter of standard spring wire and correspondingly
increase the length of the coil so that the lifting strength of the spring
remains the same. In effect what you have is a bigger spring, with the
same lifting capacity, that lasts longer. The more you increase the size
of the spring the longer it will last. (This of course must be done through
careful calculations).
For our purposes, the highlife
springs that we offer have a 2 1/2 time the life expectancy of the “standard
springs” used on most new doors. The industry standard for residential
springs is a 10,000 cycle spring, meaning it will go up and down (one
cycle) ten thousand times before it breaks.
We use that same standard as a minimum for our “standard
spring”. Our “highlife” spring us a minimum standard of 20,000 cycles.
For a nominal increase in the cost of a spring change we offer the option
of a considerable increase in performance. The number of turns required
on a particular spring is determined by the length of the cable (which
in turn is determined by the height of the door and the specific headroom
application) and the diameter of the cable drums.
Most 7’ high doors with 4” drums require approximately
7 1/2 full turns or 30 quarter turns.
Some other doors have 5” drums that would require approximately
6 full turns or 24 quarter turns.
!!--Warning--!!
We do not recommend that you attempt to adjust the
springs yourself. It can be very dangerous without the right tools or
a correct understanding of your particular system.
The colors painted on some springs will usually identify the spring size. Until about 1988 there wasn’t a universal color code for spring sizes and each company used their own. Since then the National Association of Garage Door Manufactures standardized colors to indicate wire size and right or left hand wind. We have used this color code since then.
The paint, particularly red, orange
and brown are often mistaken for rust spots and make the springs look
used when in fact they are new. Because of the high carbon content of
spring steel, torsion springs tend to rust easily, even without getting
wet they can get enough moisture out of the air to put on a good coat
of rust. Even brand new springs will rust up some from the time they are
manufactured to the time they arrive at your home.
Generally this will not affect the performance of the
spring or its longevity, but will make it a little noisy. Coating the
spring with a light oil (not grease) will usually eliminate the noise.
This is something that can be done two or three times a year to keep things
running smooth.
Not all spring designers and manufactures make springs
with the same physical dimensions, and the physical dimensions of a replacement
spring need not be identical to the original as long as the spring has
been properly converted. To do this the springs rating in terms of Inch
Pounds Per Turn or IPPT must be determined. We do this from a series of
charts. Then an acceptable spring with perhaps a different Inside
Diameter or Wire Size can be found with the same IPPT. Care must be taken
to insure that the replacement spring has an acceptable life expectancy.
To do proper conversions one needs to know what the ID or Inside Diameter
of the coil is, the wire size in 1/1000’s of an inch, the Coil Length
and the Wind of the spring (RW right hand wind or LW left hand wind).
Other significant conversions that can be made by using IPPT is the ability to convert from a one spring system to a two spring system or from a three spring system to a two spring system, or in situations where the springs are not of equal size. Most larger doors (16’ wide) have two springs. These are attached to a single shaft so that each springs lifting capacity (IPPT) combines with the other for a total IPPT required to balance that particular door. Usually these springs are attached to the header to a center plate that attaches the springs on their stationary end to the header of the garage door. In cases like these one spring must be wound one direction while the other must be wound the opposite so that when they are wound up they will both lift the same direction.
As far as lifting ability is concerned
it does not matter if one spring or multiple springs are used as long
as the totals are correct. For example, if a given door requires 65.2
IPPT to successfully balance the door, this can be achieved by the use
of a single spring with a 65.2 IPPT rating or two spring with a 32.6 IPPT
rating each. The same door could use one spring with a 26.0 IPPT rating
and a another with a 39.2 IPPT rating.
It is preferable however, to keep the springs close
to the same size to minimize back and forth movement of the shaft while
the door operates.
Doors larger than eight or nine feet wide are better served by two springs than a single spring for the same reason. On extremely heavy doors, usually commercial applications, where more than two springs are needed it is best to use even numbers of springs to avoid the same back and forth movement of the torsion shaft.








