How Garage Doors Work Archives - DDM Garage Doors Blog

Garage Door Pulleys

Saturday, June 17th, 2023 at 11:11 am by Philip Kendall

Garage door pulleys are part of the counterbalance system for extension spring doors. Most doors have four pulleys, or two on each side. There are two stationary pulleys, and a pulley attached to one end of each extension spring. Garage door pulleys are not the same as cable drums, which perform a similar function on garage door torsion spring assemblies.…

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Twin Contact Bottom Seals

Tuesday, May 9th, 2023 at 2:35 pm by Philip Kendall

Garage door bottom seals act like a garage door gasket. They keep water, debris and small animals from coming in under the bottom of your garage door. Since there are a variety of different types of bottom seals and retainers, deciding which type to use can be difficult.…

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How Commercial Operator Clutches Work

Saturday, December 31st, 2022 at 1:11 pm by Philip Kendall

Commercial Operator Clutches are one of the safety devices that operator manufacturers use to keep their doors from causing injuries or damage. The clutch will slip, which keeps the operator from forcing the door open or shut if something is obstructing it.…

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Different Types of Limit Switches

Wednesday, November 2nd, 2022 at 8:04 pm by Dan Musick

Limit switches are used to keep the garage door opener from trying to open a garage door that is already open, or trying to close a door that is already closed. Throughout the history of garage doors, engineers have come up with a wide variety of limit switch designs.…

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Amarr Pinch-proof Doors

Wednesday, October 5th, 2022 at 3:17 pm by Philip Kendall

Amarr created a unique, pinch-proof design for their doors.

The basic principle behind pinch-proof hinges is to prevent people from trying to close the door manually by sticking their fingers between the sections of the door. Smashed fingers have led to numerous lawsuits.…

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How to Counterbalance a Bi-fold Hangar Door

Saturday, May 7th, 2022 at 9:40 am by Liz Dzik

Usually, you can find large bi-fold hangar doors at airports or in specialty production shops. We get requests for torsion spring hardware to counterbalance smaller bi-fold doors from time to time.

A view of a bi-fold hangar door that is partially open.

On bi-fold doors, the top of the door is hinged and secured to the outside top of the opening.…

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LiftMaster Logic 5 Voltages

Friday, September 25th, 2020 at 3:36 pm by Dan Musick

In most commercial operators sold in the last century, there were two voltages: the incoming line voltage, and the lower secondary voltage from the transformer. This was usually 24-28 volts with alternating current. On rainy days in my early years, this lower voltage would often produce a noticeable shock.…

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Functions of a LiftMaster Logic 5 Control Board

Friday, September 11th, 2020 at 2:09 pm by Dan Musick

Four-wire motors

When I first got into the door business, the most common wiring for a 110-volt circuit consisted of a four-wire motor and two power leads. The two power leads ran straight to the motor. The other wires from the motor could go to either power lead.…

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Counter and Timer Modification for LiftMaster Operators

Tuesday, September 8th, 2020 at 4:10 pm by Dan Musick

In order to test the cycle life of different spring systems, we designed a Counter and Timer Modification for LiftMaster Operators. This modification allows the operator to close immediately after opening and to open immediately after closing. As a result, we can run the operator nonstop for days at a time so that a 10,000 cycle test can be completed in just a few days.…

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Limit Switches

Friday, August 28th, 2020 at 5:02 pm by Dan Musick

Garage door opener limit switches electrically limit the door travel as it opens and closes. These switches “tell” the opener or operator when to stop. In this video, we explain how LiftMaster limit switches work, and how to adjust them.

How they work

LiftMaster uses a common system of nuts on a shaft to limit the movement of garage doors.…

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