While I have NO specific knowledge or experience w/ th plastic coupler of your seat, I would opine a bit about the retort that you received from the "parts guy". I suspect that he was quick-witted and sensed your frustration w/ this obviously ill-designed piece. In that vein, he quipped that they break all the time & that it was designed that way to protect the motor. In truth, this fellow was so far removed from the engineering dept. where that assembly was designed that he more than likely had NO specific knowledge of the company's thinking or their response. He probably was playing on your emotions.....
@Zippy: I could have used a 3D printer for the driver's side door handle on my 2005 Chevy Cobalt. I went through two of them in three years. The original broke when I accidentally closed the door on the seatbelt. I pulled too hard on the door trying to open it and the handle snapped. There was enough of it left, though, that I could still open the door (once I successfully extricated the seatbelt, that is). However, my wife thought it was a disgrace for an engineer to have a car without a drivers' side door handle. Later that year, we visited my wife's brother, who owns a car dealership. He asked me if there was anything I needed. I said, "Well, yes, actually, there is." He gave me a brand new chrome door handle as a Christmas present. Everything was great until the following winter, when on a particularly cold day, the chrome handle snapped. This time it didn't leave a stub to allow me to open the door. I decided to get used to the idea of not having a drivers' side door handle. This was no problem when taking my kids to school, since I would just let them in the car first, and have them open the door for me from the inside. Climbing in from the passenger side when driving by myself was a little inconvenient at first, but I got used to it - so much so that nw that I have a new car, I instinctively go to the passenger side.
Thanks for weighing in on plastic gears, GTOlover. Tiny cheapo plastic gears in clocks mean that those clocks won't last long enough, at least for some of us. Way, way shorter of a lifetime than metal. It was evident to me that they were yet another mass-production lowering-prices strategy. And the quiet is a good thing. But as Elizabeth pointed out, it was a poor design decision to sue that particular material. Not only do they wear out much sooner, but clock repair guys tell me they can't repair them. So I'm left with a nice looking shell--which, of course, no one's making anymore--and gears that don't work but can't be replaced. All destined for the landfill.
Dave, good point about engineers having to understand the unique material properties of polymers.
Creep, stress relaxation, outgassing. What? You're using nylon in water?
I think I'm the only one of the 50-odd engineers at my company that has actually taken a course in design using polymers. Whenever there is an issue with a plastic design I always offer to help. Have they done a Time-Temperature transformation? Have you figured out the apparent modulus so you could design the part to the expected service life based on the stresses it will see?
Oh well, I'm just the old guy...what do I know? :D
Dave Palmer, THANK YOU for putting that link to Joseph Ogando's article on plastics. I read this years ago but couldn't remember the title or the author so was never able to find it again.
This article should be required reading for all plastics designers. And I will be keeping it in my back pocket as a reference when I have to explain what I call the "plastics uncertaintly principle" to non-plastics engineers or decision makers.
As someone who molds plastic gears, I should point out that plastic gears work very well in some applications! The main benefit is they run quiet and some plastics self lubricate. I believe they found their way into clocks and watches is the cost to mass produce gears in plastic is miniscule compared to a metal gear.
I also think that plastic gears found their way into other products, like cars and wash machines, is the cost to manufacture the plastic gear is low. Also, the plastic gear runs quieter in operation. However, they may not always last as long as the metal gears and are subject to enviromental degradation leading to premature failures.
Also Ann, glad to hear your husband is still kicking. I chuckled when I re-read your reference!
With the rapid improvements in 3D printing processes, equipment, and materials, perhaps we will see the day when a dealer (or even a handy product owner) could produce replacement parts inexpensively and on demand without keeping inventories of parts.
I had a similar problem with my 2006 Jeep Liberty. The plastic part that connects a cable to the window broke. I was told by the dealer that some of the Jeep Liberty window regulators were recalled and replaced for free. This was not the case for me. My plastic part was not sold separately. My new window regulator cost $30. I installed the new window regulator in one hour. The replacement part design was improved. There are some good youtube videos showing how to replace the Jeep Liberty window regulator. This seems to be a common problem.
This story reminds me of a Subaru Justy i once owned. Normally Subarus are great cars, but this one was a very low end, tiny piece of junk. While still under warranty, the driver side seat back broke. You would think it would be covered, but the service manager told me it wasn't (I later came to believe he had lied to me to make more money, but that's another story). He said he could charge me $300 for the metal bracket inside the seat, plus labor to rebuild my seat. I knew it was a ripoff, and refused to pay it. Instead, I searched local junkyards, and managed to buy two front seats for a grand total of $70. They installed in less than 15 minutes, with four bolts each.
Linear guides are one of the most important components required for the development of automated or computer-controlled equipment. Aluminum profile extrusions, used for these guides in machine design, can enable designed-in functional features.
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