Another key safety concern with a garage door involves the section joint and other gaps or entrapment points on a door. The Consumer Product Safety Commission estimates there are as many as 20,000 injuries a year related to garage door use in the United States.
Springs that lose tension or relax over time can pose a significant danger if the garage door is released from the opener, while in the up position—potentially leading to a free falling door.
The bottom roller brackets located at the bottom corners of the door are always under extreme tension since the counterbalance cables are attached to these brackets. Therefore, one should never attempt to remove or loosen the screws that attach these brackets to the door as serious injury can result. This also applies to other spring hardware such as the setscrews, cable drums, lag screws, lift cables, etc.
Most overhead garage doors are equipped with torsion springs which do not need safety restraint cables since the torsion shaft running through the springs restrains the spring if it breaks. Torsion springs are superior to extension springs since they are easier to fine tune and balance the weight of the door more evenly. However, torsion springs can be life threatening to an unsuspecting homeowner trying to replace a spring or fix the center spring support bracket.
Garage doors with extension springs would normally be installed with a restraint cable running through the center of these springs. This is necessary because the springs weaken from the fatigue and stress exerted on the steel wire from opening and closing the door. If an extension spring breaks, it can seriously injure anyone present in the garage or damage adjacent property. The cable running through the center restrains the spring in the event of a failure.
All moving parts of the door should be lubricated monthly. The door tracks should never be lubricated since the lubricant will only create a sticky surface on the track that can attract more dirt and grime, resulting in a door that is really difficult to operate. The bearings, hinges, and rollers should be lubricated for proper and safe operation. Torsion springs should also be lubricated with a light coat of oil to reduce the friction between the coils and to eliminate any noises and to even increase the life of the springs.
The balance of the door should be checked monthly. One should be able to raise and lower the door without any resistance and it should smoothly roll along the tracks and should remain stationary at any point of travel. Usually a door that does not pass these tests is out of balance and should be adjusted.
An extension spring counterbalance system consists of a pair of stretched springs running parallel to the horizontal tracks. The springs lift the door through a system of pulleys and counterbalance cables running from the bottom corner brackets through the pulleys. When the door is raised, the springs contract, thus lifting the door as the tension is released.
?Extension spring lift mechanism
Other factors like poor garage door maintenance, loose tracks, or components will shorten the life of torsion springs. Owners are advised to avoid applying grease to the garage door tracks, this will prevent the wheels on the rollers from doing their job. Only the bearings, hinges, and spring wire require lubricant.
Most garage door manufacturers, garage door dealers, either produce and sell garage doors fitted with torsion springs that have a minimum of 10,000 – 15,000 cycles which is estimated to last between 3 to 7 years. However, it is important to remember that if the weight of the garage door is increased by adding glass, additional insulation, or even several coats of paint, the life of the torsion spring may be greatly be reduced.
?Life of torsion spring
A torsion spring counterbalance system consists of one or two tightly wound up springs on a steel shaft with cable drums at both ends. The entire apparatus mounts on the header wall above the garage door and has three supports: a center bearing plate with a steel or nylon bearing and two end bearing plates at both ends. The springs themselves consist of the steel wire with a stationary cone at one end and a winding cone at the other end. The stationary cone is attached to the center bearing plate. The winding cone consists of holes every 90 degrees for winding the springs and two set screws to secure the springs to the shaft. Steel counterbalance cables run from the roller brackets at the bottom corners of the door to a notch in the cable drums. When the door is raised, the springs unwind and the stored tension lifts the door by turning the shaft, thus turning the cable drums, wrapping the cables around the grooves on the cable drums. When the door is lowered, the cables unwrap from the drums and the springs are rewound to full tension.
?Torsion spring lift mechanism
A common material for a new garage door is steel sheet formed to look like a raised panel wooden door. Steel doors are available in uninsulated, insulated, and double skin steel. A design mimicking carriage house doors has become quite popular since about 2002, and many manufacturers clad the exterior of a steel door with composite, vinyl boards, or DecamTrim to give it the appearance of wood. Steel carriage doors are becoming the most popular carriage door due to weight of the door, no rotting, and a large amount of designs. A more economical alternative for garage doors is steel stamped construction.
?Materials and insulation
In the UK (and other parts of the EU), ‘insulated’ roller garage doors are available, using an aluminium lathe which is then foam filled, which not only adds thermal but acoustic insulation.
Roller doors are usually constructed of corrugated steel. Other materials can be used (eg; transparent corrugated fibreglass) where strong impact resistance is not required. Corrugations give the door strength against impacts. A typical single car garage roller door will have a preloaded spring inside the rolling mechanism. The spring reduces the effort required to open the door. Larger roller doors in commercial premises are not sprung and use a manual pulley and chain system or a geared motor to raise and lower (roll up and roll down) the door. Roller doors cannot be effectively insulated.
?Insulation of Sectional Garage Door
Garage doors can be made out of many materials, but steel, aluminum, wood, and vinyl (polyethylene) are the most popular materials. A few manufactures are making energy efficient garage doors by putting foamed-in-place polyurethane insulation in monolithic panel and sectional garage doors.
Sectional doors are usually constructed of six to eight panels and slide up and overhead. Sectional doors occupy exactly the same amount of internal garage space as a monolithic door. Sectional doors have two distinct advantages over single panel monolithic doors: – Sectional doors do not require any space outside the garage to open. A vehicle may park very close to the garage before opening the door. – Each panel of a sectional door has its own connection to the door track. This increases reliability and robustness compared to a monolithic doors which has only a couple of track connections for the whole panel.
?Sectional garage doors
Single panel doors are constructed from one monolithic panel. From the closed position a single panel door will slide up and overhead on rails to the fully open position. A disadvantage of monolithic panel doors is that the swing up arc of the door occurs partially outside the garage. This means a vehicle must stop and park several feet in front of the door to avoid being hit by the garage door when it is opened.
?Single panel garage doors
?Sectional-type overhead garage doors in the style of carriage house doors. They are steel with exterior cladding.
?Up-and-over garage door.
A typical overhead garage door consists of several panels hinged together that roll along a system of tracks guided by rollers. The weight of the door is balanced by either a torsion spring system or a pair of extension springs. The upward-lifting garage door was invented in 1921 by C. G. Johnson, who also invented the electric garage door opener in 1926.
?Sectional garage door.
7 Extension spring lift mechanism
6.1 Life of torsion spring
6 Torsion spring lift mechanism
5 Materials and insulation
4 Roller doors
3 Sectional garage doors
2 Single panel garage doors
A garage door is a large door on a garage that can either be opened manually or by a garage door opener. Garage doors are necessarily large to allow passage of automobiles and/or trucks.
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