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.
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 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 ...
Robots that walk have come a long way from simple barebones walking machines or pairs of legs without an upper body and head. Much of the research these days focuses on making more humanoid robots. But they are not all created equal.
The IEEE Computer Society has named the top 10 trends for 2014. You can expect the convergence of cloud computing and mobile devices, advances in health care data and devices, as well as privacy issues in social media to make the headlines. And 3D printing came out of nowhere to make a big splash.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.