Inexcusable Bad Designs 3

[jmw]

There are several interesting threads here, and in the engineering history forum, that prompt this new post.

In engineering history the seacrh is on for the greatest engineering achievements and the greatest failures.

In this thread we have questions about "What is safe?" and there is another thread in this forum about the ethics of limited designs in "Design and Supply".

Here I want to give an example of bad design which I feel is potentially dangerous and inexcusable and to deiscover other's opinions on this and any other examples.

I won't name a brand or model as this may be leading into a litigeous area. Here I wanted to explore the engineering reaction to bad design.

My example is the particular make and model of rotary lawn mower my elderly parents purchased. Low cost and widly available I think there is an inherent dange in these and other designs that, because of circumstances, may not leave the manufacturers legally liable. You will see what I mean, but will, I think see that here the law is an ass.

The worst of this is that there are good designs out there and there is over a century of mower design history to call upon, so there is no excuse for bad design.

This is not about ground breaking, envelope pushing design innovations that can occassionally go wrong but which, overall, are but one valuable learning experience on the path to better things.

Here we have a simple excercise in taking modern design aids, modern manufacturing and the benefits of mass production and the acculmulated years of experience which should produce an excellent product at a very affordable price.

That is the expectation.

It is not a case of "you get what you pay for" because in every endeavour engineers are delivering better designs and more capability for lower prices.

The expectation is justifiable.

This product confounds the expectations:

For example,
[ul square][li]It has four wheels, all are outside the cutting path; you cannot mow verges except on a diagonal where one wheel floats in air.[/li]
[li] the path from the cutter to the grass collector is obstructed by several braces which presumably keep the mower deck walls from flexing: when the wind blows, or collapsing inwards due to the low pressure expected from the action of the cutter blade, if it moved fast enough, but which, because of the very low reving engine it doesn't; or simply from impact damage e.g. when struck by a foot (a real expectation due to the frustration created).[/li]
[li]The grass collector has vents in the bottom and sides but none in the top or back so the first collected cuttings block the air flow. [/li]
[li]The next cuttings block the throat. The collector requires emptying when only half full or less and the grass does not compact.[/li]
[li]It may be excellent on astro-turf or in the desert but on a moist english lawn grass that can grow an couple of inches in a week, forget it.[/li]
[li]OK, so when the first Japanese machines reached the UK they did discover serious problems with the cutters because their blade design was based on quite different low-silicate grasses, but that was decades ago.[/li]
[li]This grass collector can require emptying every ten to twenty feet or so and the throat needs clearing each time.[/li]
[li] it has a dead mans handle throttle so, after you've crippled yourself extracting the grass box from under the fixed rake handle bar, and discover there is no tumble home to the grass box such that half of the grass falls straight out onto the lawn as you remove it, the engine stops.[/li]
[li] The engine stop is supposed to be a safety feature but the frequent need to stop, empty the grass collector and clear the blocked throat means that it requires pull-cord staring every ten feet or so when used on some lawns.
The consequence is that operators simpley defeat the throttle safety with a piece of string, because the safety feature is childishly easy to defeat.[/li]
[li] Operators now can be seen emptying the grass box and clearing the throat of the mower with the engine running.[/li][/ul]

Such designs are potentially dangerous and, worse, avoidable. A better design should cost no more but am I alone in noting that many bad designs are prodiuced simply because they can charge so much more for better designs which cost no more to produce?

Where are the ethics in this? What engineer of any integrity can be party to such designs?

I wonder, just how many other inexcusable designs are there?




JMW

http://www.viscoanalyser.com

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[NormPeterson]

.
My example is the particular make and model of rotary lawn mower my elderly parents purchased. Low cost and widly available I think there is an inherent dange in these and other designs that, because of circumstances, may not leave the manufacturers legally liable. You will see what I mean, but will, I think see that here the law is an ass.

Not to throw flames, but the way I’m reading the topic-starter, this purchase decision was your parents’, not yours. So let me suggest that your parents probably chose that particular mower based on a slightly different perspective as regards respect for powered machinery (especially as applied to tools intended for cutting stuff) and personal responsibility than can be expected of today’s lowest-common-denominator customer. You, as an IE, probably have more contact with issues involving said L.C.D. individuals. Their specific age is not important beyond some presumption of physical ability to use the mower. But I’m sure that they remember when the only rotary lawn mower “safety feature” was a toothed plate mounted on the rear wall of the deck, intended, more or less, to keep the feet from being run over. And when grass collectors were rare. That's part of their basis for choice.

It appears that the bracing scheme is mostly the issue here. You need something, as the deck is otherwise a flattish thin plate that supports a couple of sources of vibration (read: fatigue and, ultimately, cracking – or needlessly heavy) but which is not equally supported around its entire periphery by the walls. Structurally, the grass discharge opening is a “soft” spot between two of the wheels. Presumably there are better solutions, and this should be part of next time's purchase decision process.

On the safety items, believe me, I fully understand the frustration with budget-minded and/or less than fully thought out approaches to [lawn mower] safety as well as the unintended consequences of same (isn’t there an anecdotal “law” by that title?). I’m more than a little insulted, actually, when such features pre-empt my own judgement (which has been serving me reasonably well so far, as I approach my 57th birthday this fall). It implies that some entity considers me to be an utter moron, at best only marginally qualified to operate the product (by virtue of having a non-zero pulse and enough money or credit to purchase it). Hence I need to be protected against myself.

Norm

 

[DRC1]

I agree with jmw. The design appears to be bad on many counts and the flaws are fundemental in nature. He is right. As a profession we should not excuse bad design or we lower the stanards.

However I think the central issue focuses around jmw's observation that we have over a century of mower design experience.

For many years the US has exported manufacturing overseas to low cost 3rd world producers. However the design and development of these goods was still done in the US, Canada or Europe where this experince was available. However the third world has been exporting engineering students to these countries and have devloped the ability ty begin there own design work. Armed with little historical design background, no budget for testing and devlopment and a low price point, they are making their own mowers. The price and cost is low enough that they will sell enough that even if they are not very good, they wont get hurt. As they learn, the mowers will improve. I bet if you check the manual, you will see that the mowers are made overseas. My guess is that they were designed there too.
This is a serious problem. The rapid decline in western manufacturing will continue to have a horrible impact on our standard of living. We need to make our societies aware how important manufacturing is to us.

 

[Smartech]

This thread brings to mind my latest rant... I cannot believe the management of many companies ever use their product at all. Seems to me it's all about selling the most for the least, and avoiding liability, not making a product that works. One simple example, anybody here in the US try to open milk cartons lately? Used to be you pried two glued together flaps apart, and then kind of pushed them open to make a nice little pour spout. Now the glue is such that you need to either rip the damn thing open or use a knife, but they sure don't work. I assume they are using a stronger glue to avoid tampering. I think that a new opening design is a better idea.

OK Rant over

 

[JamesCG]

That last one isn't a problem in the UK as good old TETRAPAK(TM) have devised a whole number of openings for milk and juice cartons (possibly why Hausing - i think his name is - is one of the richest men in the UK)

 

[jmw]

Ah! But only because Hausing(?) made the mistake of going on TV to defend his product against claims that it was badly designed. The interviewer just happened to have a carton of orange juice or something available and suggested he demonstrate. He did. He covered himself in juice.

Possibly the first time he had used his own product in years and a good lesson in testing things before demonstrating them.

Needless to say, a string of deisgn improvements followed.

But don't let's get onto packaging designs or you will get me started on "tamper-proof" packaging and ow the elederly are starving to death because they can't open food packaging or "child-proof" caps on medicines. Is it just me who has noticed that often, the only people who can open these things are children?

JMW

http://www.viscoanalyser.com

Eng-Tips: Pro bono publico, by engineers, for engineers.

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[gibfrog]

JMW:

I have bought and used many different rotary lawnmowers in Florida, USA. Your complaints are baseless.

1) Check out 8+hp walk behind mowers or standing rider units. The wheels are well within the cutting swath. These are heavy commercial mowers. Lawn sweepers may be towed behind to pick up cuttings on self-propelled models. The edge cutting is not great due to limited manuverability.

2) On the 22"-30" standard single blade rotary mowers, the wheels are outside the cutting swath. Either cut perpandicular to the edge and push the front of the mower over the it or try a weed wacker/string cutter. Tall moist grass will always clog these rotary mowers, without or without a bag attachment. Try cutting in the late afternoon on a day without rain for optimum performance.

3) Check out other wheeled string cutters. These mowers have no edge limitations. However, they do not collect grass cuttingsare are more of a commercial type mower with limited brush cutting capabilities.

4) You are unrealistically a device to multi-function perfectly. First function is to bulk cut grass, second function to collect the grass cuttings and third function is to edge cut. Sacrifices and compromises are made for safetry, ergonomics, economy and multi-functionality.

5) You are an engineer, design a better mower.

6) Buy your parents a robotic lawn mower, mow more often with a mulching blade and just dethatch annually.

7) Replant the lawn with a slower growing grass or alternate ground cover (mulch, concrete, astroturf, etc). Try growth inhibitors if your parents would like to mow the lawn less frequently.

Cliff Laubstein

 

[ICman]

The design may have been driven by the design of other mowers. Of course, some things are basic to all rotary mowers, but many ideas are patented. Therefore, the designers may have wanted to come up with something "unique" to avoid infringement with competitors.

Many aspects of the design are for marketing purposes. Myself, I bought a cheap lawnmower and applied a Harley-Davidson sticker to it. It would probably sell for $100 more.

I bet that most lawnmowers are purchased without a lot of study. The old one breaks, you stop at the local lawn center and pick a new one out. Maybe this time you get the one with front-wheel drive, or a larger deck. It is doubtful many purchasers look at the vent location or placement of the wheels.

The ultimate solution: Buy a Honda lawnmower!

 

[davidinindy]

We just rented a middle-class "unnamed make" car that had so many controls ont the turn signal and another stalk on the opposite side, that were hidden by the bulky steering wheel, that it was literally dangerous to drive. We had to take our eyes off the road for an extended period of time to find where the wipers were. The cruise was also on the inside stalk, but I didn't even try to use it.
The pedals and steering wheel were not spaced properly either. I'm 5-10 and average build. i ussually have no problem getting comfortable in any car. In this car, if my legs were comfortable, I could barely reach the steering wheel. Not to mention the seats were like sitting on a metal folding chair.
The armrest on the door was also too far forward when the seat was back far enough to be comfortable. It's like it was designed for someone with extremely short legs and long arms.
I can't get over how badly this car ws designed.

 

[pba]

One of JMW’s concerns seems to be that poor design is perpetuated by a company that he perceived to be competent and established within the particular market of English lawn mowers. I agree that we should expect improvements in design over time and that lawn mowers have been around long enough that they should be very good across the board, from the cheapest to the most expensive. It seems probable that the mower in question has suffered reverses in ‘quality’ probably due to cost engineers rather that real engineers. I expect that lawn mower manufacturers employ very few real engineers. This may change when the company reputation starts to suffer.
I bought a mower five years ago. I bought the cheapest mower I could find from a well known name (Flymo). The mower has never been brilliant, but it cuts the grass and still works. The basic design of this mower is very similar to one my father used in the 1970’s. I’m keen on the fact that the design is tried and tested - I don’t want newfangled.

 

[Slowzuki]

We currently own 2 rotary lawnmowers produced by Lawnboy. One is a 30 year old unit, was a base model unit with a light magnesium deck, large rear wheels, small engine. Wheels are inside the track width, one wheel is off the square pattern so the blades have ideal discharge off the tips and you can mow around a tree without a trimmer.

We also have a 10 year old Lawnboy with a cheap, heavy stamped steel deck, tiny wheels arranged in a square pattern (at least inside the cut width)

Both these mowers came from the same market segment, and same company, with the first one being a far superior product.

What happened?

Cost cutting measures altered the construction techniques.


Now to the product in question, take the grass catcher off. Problem solved. It gets chopped up and fertilizes the lawn.

Do you realize the modern concept of a lawn is less than 100 years old? I hope to design the landscaping of our future house to elinimate this machine from my workload!

 

[jmw]

So the first lawn mowers pre-date the first lawn?
Before lawn mowers the gentry had lots of yokel types with scythes ..... but enough for now, I've received stick enough for daring to suggest that some products can be badly designed when in fact it's all my fault.

JMW

http://www.viscoanalyser.com

Eng-Tips: Pro bono publico, by engineers, for engineers.

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[johnhanging]

All power mowers should be outlawed and replaced with manual push mowers. I find it irritating when I see an obese person driving a oversized, poorly tuned tractor/mower around a quarter acre lot.

 

[TheTick]

That sure is sound logic, Mr. Hanging. I'll write my congressman immediately.

 

[profengmen]

John,
I have an acre lot... it takes 2 hours on a riding lawn mower.

Come on over, be my guest.....

BTW, I'm not obese, not even fat... pretty fit. I'll be damned if I'm going to spend half the summer pushing around my manual rotary (which I have for trimming) because of you arrogant ideas.

 

[NormPeterson]

"All power mowers should be . . . replaced with manual push mowers."

Been there, done that. Too many years ago I used to cut a couple of lawns with manual reel-type mowers on a regular basis. Those things don't cut taller blades of grass very well, aren't easily set to leave the grass deeper (so that it won't burn as readily), and cut narrow swaths. Translation: lawn duty with an all-manual mower requires more mowing time over the course of a season than I'm willing to spend on that activity, even for a 1/4 acre plot (that's what the manual rotaries are for).

And I'd rather get my exercise from free weights and bicycle riding anyway.

Norm

 

[Ron]

jmw....gather back your ego and think it through again. First, you have assumed the mower was designed by an engineer. Fairly often such products are designed by a.) trial and error by a relatively handy guy; or b.) R&D, which in this case means "Remember and Duplicate" as in copy someone else's horror and put your own spin to it (no pun intended on the rotary mower!). Second, you have lost your objectivity by personalizing it and your frustration shows in having to deal with a product which you do not like. Remember, that's how competing products are born....you don't like something someone else produces so you set about to build a better mousetrap (or mower).

If you talk to the guy who "designed" your parent's mower, I would bet that he could defend each of the design "features" with vigor and passion.

I suppose if you consider the design to be onerous and dangerous, you might want to consider not letting your parent's use it.

 

[jmw]

Well this brings us back to the ethics issue.

Most products have to be safe and fit for the purpose intended, in some countries both are legal requirements. There is no "buyer beware" loophole.

There can be poor products that don't fit the market needs, there can be products that don't meet their financial objectives.

When introducing new products, they don't have to be right, they get better with each evolution. When intoruding "me-too" products they ahve to be right and competitive and even then need some help.

I will say here that i am, in many buyin situations, not an expert on what i buy. I have bought wrong products before, innappropriate products and expect to do so again. Like most people i depend on reputation, brand names etc when buying because this is one of my assurances that what i buy will be well thought out and designed for people just like me.

If i was a lawnmower expert, then i could be expected to recognise a 100 or more different design features and make an on the spot evaluation of buy or not buy.

No one buying consumer products is a specialist in what they buy. They are a consumer. They have a right (under law) that it is safe and fit for the purpose intended.

One of the wasy consumers can be relatively confident that they can buy products with a reasonable expectation that it has been well designed is to buy brand name products from recognised suppliers. This is what branding is all about.

When dealing with a reputable supplier or internationally recognised company, especially in such a litigious age, what company could/would/should have its products designed by a "relatively handy guy" or an accountant?

Who signs off the product?
Who takes design responsibility?

Whoever does do the design has to be competent to do the work. Whoever signs it off has to be satisfied that it meets the specs.

Marketing should present a specification for a product wihich, with certain features, which should command a certain price in the market and take a specific share of the market and it is then up to engineers to design the best product they can within the allowed cost and if they can't, to say so.

I know that many engineers are keen to design the product they would like and not the product that will sell. I've seen this happen. I have seen the consequences. I have also seen products designed by a team of engineers and marketing specialists and so on and seen it doen well and seen what a successful product is.

Titanium is a wonderful material. We could probably make a marvelous lawn mower from it but low grade pressed steel or aluminium is fine. It doesn't have to last a lifetime anymore because the cost of replacement is cheaper than the lifetime cost of annual service and repair. AT some point its value depreciates to zero. That doesn't make it a bad design, rather , it is a good design because it meets its design objectives.

It is not whether a product has added features worthy of extra price but that in a product which has evolved for over 100years, poor design features are incorporated in a design which, for the same money and features, would appear to be better designed by other manufacturers and have been better designed in the past. This isn't an evolutionary thing.

It also seems to me that there is an assumption that if an engineer was involved the product can't be bad, it is the buyer who is wrong or that if the product is bad and the buyer is right, then it wasn't designed by an engineer.

I should say that i started this thread not to slag off a particular product but to raise the question of good and bad design. No, inexcusable bad design, since in the real world we know bad designs can happen.

I guess that has been answered:
[ul][li] if it is a bad design, it wasn't an engineer who designed it[/li]
[li] if an engineer designed it, it isn't a bad design[/li]
[/ul]
If that were the case there would be no recalls on cars. We wouldn't have whole thread about engineering disasters. Some errors are natural. They result from pushing the envelope. Some are natural because engineers are human and humans make mistakes. I do. But for some things there are no excuses, or so i thought.

But the suggestion here seems to be that engineers are infallable and consumers deserve what they get.
Really?

JMW

http://www.viscoanalyser.com

Eng-Tips: Pro bono publico, by engineers, for engineers.

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Ron]

jmw....I hope you do not reach conclusions in your engineering work in the same manner that your have reached your conclusions here.

Engineers are by no means infallible. They make mistakes like everyone else. The practice of engineering is not a perfect science. The standard of care for engineering is not perfection...it is the absence of negligence.

Fitness for purpose is a somewhat nebulous term, though legally entwined. One could argue that the only thing a mower must do to prove fitness for purpose is to hack the grass off as some level. Yes, it is more complex than that, but it would appear that if you were engaged to prove that the mower were dangerous, you have only provided evidence that it is an inefficient design. Does such inefficiency beget danger? Perhaps, but that is arguable, and it is what causes attorneys (solicitors, barristers, or I'm sure others have more colorful names for them) to make more money than engineers!

To your larger point, which is certainly worthy of discussion, I do believe (and have investigated such) that dangerous designs are propounded on the consuming public all too often. Unfortunately, there must usually be some accident (harm) before such designs are contested.

 

[BJC]

One way to assure all products were properly designed would be to have central design bureaus. They could be run by the goverment, staffed by engineers who would have no motive to design anything but the best type of everything.

 

[JoeTank]

BJC,
A "central design bureau"... "run by the government"...man, that's scary thought!

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com