Why aren't counterweights used more for garage doors?

Question

One of my garage door torsion springs broke again. It makes me wonder why some sort of counterweight system isn't used instead. Torsion springs seem to have a 90 day warranty generally and are "rated" for up to 15,000 cycles. It seems like there is a lot less stress on a system that uses counterweights, this company has a counterweight system for high use places (condo buildings or businesses with large garages or car washes) with warranties for 100,000-500,000 cycles.

Is it initial cost? Space required? Just to keep repairmen in business?

Answer 1

It makes me wonder why some sort of counterweight system isn't used instead.

I'd guess it's because residential garages are normally a bit limited on space and the counterweights need somewhere to go. Torsion springs are nice because they take up relatively little room on the ceiling of the garage, as opposed to counterweights, which would need space to travel vertically and a footprint in which to travel.

If a builder was thinking ahead, he might be able to find a way to get counterweights inside of a wall, similar to what is done with counterweighted windows. This could be an issue later on if a different garage door is used that requires different counterweights since you'd have to open a wall to replace them.

A duty cycle of 15,000 equates to about 10 years if a door is opened four times a day, every day of the year. Most automatic garage door openers can be expected to last 10-15 years. You didn't mention if you have an automatic opener, but it would make sense to tie the replacement of both of these items to the same timeframe.

Safety is another concern. With torsion springs, if one breaks, it stays within the shaft/tube that it's mounted to. If an extension spring breaks, it can go flying anywhere in a garage (unless restrained by safety cables). If a counterweight rope breaks, the weight can fall on you, your child, your pet, or your expensive car. In all cases, if the supporting mechanism fails, the door can fall onto something, assuming it's not also restrained by an automatic door opener.

Just to keep repairmen in business?

I'm sure planned obsolescence is part of the issue here, but not necessarily the main culprit. All mechanical devices have a service life, and it's usually a balancing act between service life and cost when it comes to specifying a system. I can't see why a counterweight system would cost more than a spring system, but I'm not a garage door installer.

You could always ask your local garage door installer if they offer a counterweight system for a residential garage. I can't seem to find anyone online offering these for residential garage doors, though.

Answer 2

I’ll be installing a custom counterweight for my new garage door – it requires some clever engineering to make it work since a residential garage door doesn’t have a fixed weight: its track bends right above the door opening, and the part that is in the horizontal raceway provides no vertical load to the counterweight. So, as the door opens, it gets lighter and lighter.

The solution I chose is to segment the counterweight: as it descends, the segments get caught on retainers so that the effective weight of the counterweight decreases the closer to the floor it is. Each segment weighs just 3 lbs, making installation easy, and there’s plenty of them so the operation will be smooth. A silicone washer will absorb the shock of the segments coming into contact with the perches and with the counterweight stack.

Another solution I considered was a linkage (4-bar or two of them in series) to scale the load – not a problem with designing it; but manufacturing it would be too much effort for me.

Another workable solution would be a cam that could even be manufactured out of wood, but I didn’t care enough to set things up to actually do that.

Since the counterweight will be made of a stack of custom cast cement blocks, with attachment points for skate bearings as raceway rollers, it will have a small footprint and will be confined to an enclosure.

I’m designing the system with a factor of safety of 5 after redundancy is lost, and the weight reduction system makes it inherently safe on the counterweight end of things: by the time the counterweight hits the bottom of the enclosure (a.k.a. the floor), it will weigh about a pound (from the point of view of the door) and that will be only the retainer plate for the cement blocks, as all the blocks will be resting on their padded perches throughout the travel range.

I have figured a 3D printed last-resort brake for the garage door, so if both redundant cables snap on either side, the door will be immobilized by the sacrificial brake parts.

The cables are going to be a redundant pair for each side of the door, with separate attachments to both the door and the counterweight stack, so that no single point of failure will affect both cables at the same time. The cables will be routed in a PVC pipe for confinement in case one snaps. The idlers for the cables are 11in diameter cast iron parts with suitable grooves that I found at a junkyard – I installed four ball bearings at each end of the cast shaft sleeve, and the shaft will be supported on both ends. This provides a decent bend radius for the oversized cable – twice as large as the minimum from the cable spec sheet. It also will look quite steampunk I think.

I expect the counterweight system to be maintenance free and to easily outlast the house. I hate the garage door springs with a passion – I have dealt enough with them to just lose all respect for whoever came up with the idea, for the execution is so poor.

I’ll also install my own opener – a junkyard worm gearbox I found in perfect condition, and a standard electric motor – both oversized for the job. A simple and reliable cable tension “sensor” will provide overload and safety protection – a really simple system that will disconnect power to the motor and short the windings for electrodynamic braking should the cable get too taut or gets pulled too hard.. No electronics: just a spring loaded rocker with a roller, and two adjustable cams on the rocker to trigger a set of micro switches (again, redundant). The motor has soft start. The opto sensor “eye” will be a standard industrial Omron part that should last forever in the conditions I will be using it in.

So, all in all a counterweight system is perfectly feasible if you want to make one yourself; but perhaps most people wouldn’t pay the cost if it was a commercial product. It would cost way more than a spring does. Unsightliness-wise, it will be neatly tucked in the space between each door and the side wall. Nobody will even notice it’s there if they won’t be told first :)

I’ll probably update this answer once I get some pictures whenever I find time to install this thing.

Update: installation is happening as I write this.

Answer 3

Seems like to me the reason is a counterweight provides a constant offset to the door weight and that weight changes as the door is brought back to horizontal. I suppose there would be a way to design a variable counterweight mechanism but that would end up more complicated(costly) than the springs.

Answer 4

The reason counter weights are not used anymore is due to a couple factors. The limited space like they mentioned in the above comments but the main reason for smaller residential garages the added weight of having heavy weights hanging on the side of the door header does nightmares to the structure over the years. I'm dealing with a job right now where the entire front wall has warped due to have heavy counter weights hanging for years. When a spring is used all the tension is on the spring itself and not on the structure.

Answer 5

In most of the residences, the garage door is constructed in a limited space and due to this counterweights are not used more. As this requires huge space, it is not applicable for those who are living in a small area. If we use counterweights, sometimes there can be jamming which can affect the garage door. Now, most of the local garage door installer doesn’t offer a counterweight system for a residential garage because of the disadvantages and limitations.

Answer 6

I'll just list some reasons counterweights are bad.

1) You need vertical space reserved for them, as opposed to the unused ceiling space for springs.

2) If a cable fails, both the door and the counterweight will fall down. Fast. And hurt something. (extension springs are required to have a retention cable run thru them, and torsion springs have nowhere to go)

3) Counterweights have to dangle freely (unless you're planning on installing a very expensive raceway); which implies high probability of interference or jamming.

Answer 7

My 2 cents: Springs are easily adjustable , counter weights difficult. I remember counter weighted windows; when the rope broke , the repair was a mess - getting into the frame. I have had many doors with both spring types and never had a spring failure ; I have had a couple cables break. And you need cables for a counter weight. I really have a hard time thinking of an advantage for weights.

Answer 8

Counter weight systems are typically manufacture using steel weights... you need pay for 100 pounds of counterweight steel for every 100 pounds of door weight. A torsion spring is 5 lbs of steel. You buy steel by the pound. Do the math

Answer 9

I think the many reasons include space, complexity in linkage and the hardware store can cram it in a short fiber mass-produced one size fits all box. I have never looked at spring loaded doors as the paragon of safety having installed and demolished a freighter load of them with many scary near enough misses regardless of proper form of action. Honestly I think counter weights are great. I have owned houses with window sash weights beautifully hidden, screen doors closed by weighty junk hung on fishing line, however they are light compared to garage doors. Most municipalities feel a permit and fee is in order regardless of the quality of junk (oops) product sold to and installed by the licensed "Professional" My guess?