My neighbor called me and asked me to come check out a problem with her garage door opener. When I went over, the problem was obvious. The drive end of the chain was lying on the floor, and the drive sprocket was still in the chain.
Worse, the drive shaft stub was still in the sprocket. The shaft was cut off clean as if by a lathe cut-off tool. As I checked into the problem, I couldn't find a bearing to support the shaft where it exited the drive module. I looked all around the floor hoping to find it, but had no luck. The shaft was supported only by the edge of the sheet metal frame. The pull of the chain had slowly, over time, completely severed the 1/2-inch shaft.
It was a well-known garage door opener brand. I had one just like it, so I examined my opener. Sure enough, mine also had no bearing. The shaft on my opener was cut about half-way through. It was still intact, but it wouldn’t be for long.
How could any designer or quality inspector accept and improve such a design screw-up? It wasn't that the brass bushing was missing during assembly. It appeared as though it was missing from the design itself.
Since the openers were both out of warranty, my neighbor and I both replaced our openers with other brands.
This entry was submitted by Robert Nepper and edited by Rob Spiegel.
Tell us your experiences with Monkey-designed products. Send stories to Rob Spiegel for Made by Monkeys.
Garage door openers move the heaviest moving object in your home, so it is surprising that the designers would omit a load bearring from the rotating object. However, it is still common to see metal on metal contact in consumer items. Ususally, the difference between professional and a consumer model from any manufacturer is the quality of the shaft bearrings.
Tim, even though consumer models do not go through the duty cycles of an idustrial product, poor design is not a good thing. As noted in the article, the two homeowners bought other brands.
Good point, Naperlou. This brand lost two customers -- and probably hundreds of others. I would also think there is a liability danger for damage to cars or people.
I wonder if this is an oversight or a deliberate design decision to save money. Either way, it's amazing that the company let the product out the door that way.
I think it's pretty clear this wasn't an oversight (since it failed out of warrantee).
Somebody probably got a hefty bonus the year they decided to cut the BOM by a couple $ (look at all the money they've saved over the years). Had the observer not been an Engineer, nothing bad would have happened to the manufacturer's reputation on discovery of this bad design.
Oh, wait. Nothing bad has happened to the manufacture's reputation since we still don't know who it is. But other manufacturer's also read this blog, so now they have an idea for future cost savings ...
I agree this wasn't an oversight. At some point in time the overall goal changed from designing the best thing you can that will last as long as it can to, build the best thing you can that will last long enough that someone won't complain when it breaks. I really hate that point in history. And I am pretty sure an engineer had nothing to do with it, because we like to make things that last forever. Until the world starts to understand that consumers will pay extra dollars for extra quality we will continue to spiral into this world of mediocracy.
I agree, Chuck. Your question is the mystery that runs through many of the Made by Monkeys postings. How could they let this happen? Why didn't somebody catch this? Once they knew about it, why didn't they change it? Very simple questions. I'd love to know the answers.
The answer lies (again) in corporate America's disdain for the very people it employs and markets to.To any given typical Corporation in the US today, there are three types of people:Employees, Customers, and Stock-Holders. Employees are expendable resources; lowest on the value scale. Customers are the next highest, but not above getting beaten down if a dollar gets in the way.Finally, the loftiest of all, is the Stock-Holder.Amazing enough, this breed of animal is the most hypothetical of all, and cannot be clearly defined; yet is most commonly referenced in reports and announcements when the CEO has his back against a wall. "We have a responsibility to our STOCK-Holders," is CEO-speak for "I need a bigger pay-raise". To heck with bushings & bearings. Only Dilbert knows what they're for anyway.
I agree, Jim. The shareholders constitute the most powerful group. If the CEO doesn't deliver a strong quarter, the shareholders can scream for his or her head. Customers can't do that, employees can't do that. Therefore, a company's management bows to the needs of the shareholders. Some CEOs can gain the confidence of shareholders and thus make some long-term decisions. But in most cases, it comes down to quarterly performance.
JimT, I agree with your ranking of Emloyee's, Customers, and stock-holders. However, this used to be a ranking that worked.
In the old days, people owned stock, and if the CEO started over compensating themselves, they got booted (no one likes seeing their own money get pilfered into someone elses pockets). At the same time, if you owned part of a company, you wanted it well run, so you were willing pay for good people. So there was this balance between being well compensated and over compensated.
The problem happened when 401K's and funds started being the primary stock-holders. That level of indirection made the fund runners the effective stock-holders (is proxy the term?). Who runs the funds? Other CEO's. So they start feeding off of each other's greed and self absorption and now they are all over compensated (actually it's a "let them eat cake" level of compensation).
What happens when a company doesn't do well? The fund runner's dump the stock and the CEO's jump ship. There is no feed back to the people that own the funds because the fund continues to do well. The company, however, fails (usually under the next CEO's watch). Everyone's horizon is no longer 5 or 20 years because they know that the investors (fund runners) only care about the extreme short term.
The sad thing is that American companies (that only care about profits in the next 6 months) can't compete in a world market (who's companies care about the next 6 years) because of this.
Being an Engineering blog, is there a solution that can fix this?
3DROB -- you and I are on the same page. Yes, it USED to work well. Stock-holders had inputs and CEOs listened. Unfortunately, the entire NYSE and other major indices are running on corporate standards that were designed in the 1930's and even earlier. It just doesn't work well anymore -- to all of the points you've detailed -- because there is no accountability. Another rotten system that long-ago had meaningful value is the concept of labor unions. Once a method to protect hard working individuals, but today, are equally as corrupt as the very companies they oppose, and still with no sense of accountability.These are GOD-sized issues I cannot begin to correct.
The door is supposed to be balanced so that there is very little load on the opener, but still, you'd think that the cycle life would dictate a bearing on the output shaft. I have a friend that owns a garage door business, so I'm going to dig into this one a little bit.
OK, I talked to my garage door guru and here's the story. Without naming names (I have friends that work for the company involved), the shaft routinely breaks on the chain version of the opener. If there's too large a load on the opener, like an improper or broken spring, or if the chain is too tight the shaft will start to wear. My door guru always carries a couple of repair kits for the chain version because the failure is very, very common. The belt version of the opener doesn't have the same problem even though it doesn't use a bearing either. There's enough play in the belt and the rubber motor mount of the belt version to prevent failure.
I think there's a lesson to be learned for all of us out there that have electric openers. The opener is not supposed to have the push the door down really hard or pick up the door completely. The springs should hold the door about half way open. Then the opener has to do just a little work to put it down or pick it up. Might be worth going home and disconnecting the opener from the door to see where you're goes. However, only do this if you have a clue of what you are doing. Adjusting springs can be very dangerous.
How about naming names? The guilty party has no defense, so they can't fight back, and perhaps if they never sold another opener, other companies would take the hint. Of course, there does exist the possible thinking that the shaft would not rotate relative to the frame, but that the sprocket would rotate on the shaft, which could serve as a sort of bearing assembly. I did have a custome motorcycle once that had a sleeve-bearing sprocket to support the drive chain on the return side so that it would not slap the frame. It never gave me any problems. Of course it did need grease every once in a while.
And I did come across an industrial machine designed by a guy named Fox, which had an aluminum arm swinging on a 1-inch steel shaft, with no bearing other than the reamed ID against the shaft. When the aluminum wore a bit the system got too loose and did not work right. The solution was a new longer shaft and two flange mount ball bearing assemblies, plus anchoring the shaft so that it could only rotate the bearings. Ifr he had elected to do it right the first time the additional cost would have been about $65 for the materials, and about 1 hour extra for the build time. The service call to fix the machine cost lots more than that, by the way.
I have an identical pair of Liftmaster openers that open the two doors of my garage. They were about 10 years old when one day the wife hit the button and the opener dropped the drive sprocket and a few other assorted parts onto the top of the car. Not sure if this is the same brand as the one in the article but it was a similar failure mode. Turns out there was an inexpensive rebuild kit available from a local garage door dealer so I installed the kits in both openers (repair for one, preemptive for the other), and both have been working fine for another 5 or so years now. The kits are way cheaper than a new opener, are easy to install in-place, and once every 10 years seems like a useful service life to me even considering it probably shouldn't happen in the first place.
The author of this story should NOT have been bashful to name the company responsible for this pathetic design. Naming the company will alert others AND will force some embarrasment to the company. SALES are JOB #1 @ the HUMUNGOUS MANUFACTURING CO. INC of the WORLD!!!! And, DON'T ever forget that!!!
I don't recall the author mentioning the type of garage doors that were affected. One blogger mentioned that the doors are supposed to be "balanced", and that's IS certainly true for a professional installation. However, IF the door (or doors) were manufactured from wood (which many are!), AND they have been installed for a long time, there are two likelihoods which no one considers. First, wood is porous, and therfore soaks up moisture. Depending on the environment, these doors may have become considerably heavier as they aged. Also, it is conceivable that since they may have been wood construction, they were also painted or stained & varnished. Again, several coats of paint over the lifetime of these doors could also add considerable weight that wasn't present when the doors were installed & balanced.
These factors, and more, could have easily changed the dynamic of the system, and therefore caused the motor to exert more torque moment to the system, thereby accelerating the wear of the shaft/"bearing" design. While I am in no way supporting an substandard design, I bring these concepts to the fore ONLY to alert people that the "Law of Unintended Consequences" can rear its ugly head in a myriad of ways!
Unfortunately, as with many consumer products, manufacturers focus on low prices as opposed to quality. However, when offered a choice, many consumers would prefer a high-quality product rather than one designed to meet a 'competitive price point'. I recently purchased a premium garage door and asked the installer to replace my 20-year-old opener at the same time. He suggested a whisper-quiet, premium priced opener: I agreed and am glad I did - guests are amazed at the quiet and quality of the new installation - about 30% higher than the 'cheap' model!
Be careful with the quiet model. When my friend installed mine he said, "OK, I'll give you the quiet one, but you're going to hit it". Sure enough, about a year later my wife hit the door. She removed her sunglasses from the visor, flipped the visor back up, which closed the switch on the opener clipped to her visor. She started backing out and since the door made no sound at all, she hadn't noticed that it was moving and drove into the half closed door. My friend was delighted to fix the door and shower me with one "I told you so" after another.
I don't have anything to add to what has already been observed, although nothing surprises me at what is done as cost reduction measures anymore. What I did find amusing was that what I first thought the article was about was a missing bear (presumably from the local zoo) that broke into someone's garage :)
I would say they cut a corner there for costs. As the saying goes they don't make them like they used to. What is a bearing or bushing really cost anyway? I just hope you examined the new unit before using it to make sure it was built better! I don't think manufacturers actually realize that by skimping on one little part like that that they can tarnish their brand forever. Fools.
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