why are helical gears used in some mechanical applications instead of spur gears or why not?
367955
The teeth of helical gears engage more smoothly (than spur gears) over a few degrees of rotation reducing vibration and noise.  Spur gears are more apt to set up a vibration each time new teeth contact and depending on speed that can cause resonant frequencies that amplify the noise or vibration.  Helical gears have less dynamic (shock) loading of the teeth and are less apt to fail.  Helical gears are used in the reduction gears that connect high-speed steam turbines to the propeller shafts of huge sea-going ships and the gear teeth are divided down the middle into two sides like a "V's" to avoid side thrust.  They are called  herring bone gears.
937903
those SRAM are the way to go these days. i had have heard alot of rave about those Sram X.0 carbon derailleurs and its superb shifting action and downshift are just perfect. XTR is just overrated because its has been so long in the market and people dont have much choice. Believer of SRAM. Cheers
1091602
Epicyclic gearing tends to fall over as you scale it up due to centrifical (centrifugal) forces of the rotating parts trying to accelerate outwards.  I'd be inclined to use a discreet gearbox off a motorcycle, something like the royal enfield bullet and chain drive.
286870
1. manual clutch or centrifugal clutch? probably centrifugal if not climbing hills.\n\n2. ratio spread. How far apart to make the gearing or belts? Too far apart and you'll never make it into second gear. Too close, and you'll not go fast. Lower first if you want to climb hills.\n\nI would suggest a sheave pulley design for continuous ratio - no gears. The sheave is spring loaded so the belt digs down into the pulley halves when high torque occurs. Kind of an automatic transmission. Check www.graingers.com,\nsearch on "sheave".\nHave fun.
971174
Cyclo converters are used to generate power with different frequencies. Once we have a different frequency wave form is availabe, it can be used to generate heat by induction with the help of other waves of different frequencies due to frequency mismatch issues etc.
286905
The short answer is standardization.  Most threads are righthanded so that people will turn them the same way to tighten or loosen them.  Probably the original (handmade) threads were righthanded because the majority of people are righthanded and more closing force can be exereted to tighten or shut in the clockwise direction.\n\nLefthanded threads are used for specialized applications such as on B-B-Q propane tanks to avoid connection to wrong fittings.  Also wheels on the left side of cars at one time used lefthanded threads because the forces on a wheel hub would tend to tighten vs loosen loose lug nuts.\n\nStandardization permits productiuon of threads with a minimum of machines (little duplication for right and left threads) and nuts and bolts can be stocked almost exclusively as righthanded.\n\nThe threads are not righthanded because of the "righthand rule of engineering" but the rule would not work without the standard thread convention.
61020
cause with more wheels you wouldn't be any faster, just less likely to fall over. \nEach wheel generates friction while in contact with the road, so with more wheels you would need more energy to go on. Apart from friction on the road you also will loose energy by friction between all the moving parts for energy transmission (chain, ball bearings and so on). \nIn addition with more wheels your "multicycle" also will inevitably get heavier. That means you need more energy/effort to accelerate it, and also more to stop it. While going downhill will be easier going uphill will be harder. \nAlso you could not lean into a curve.\nYou would also need more space on the road. With a lot of car drivers behaving like they do, as you are much slower than a car you would get honked at a lot. \nActually, you only need one wheel, you can also unicycle. It does take more practise though, so most people choose two wheels.
1033255
Manufacturing companies build a lot of specialized equipment in order to produce their product(s). It must be designed to run at highspeeds, dependability, etc. You would be amazed at some of the machines I have worked on. I am a special equipment technician and some of the machines my fellow co-workers have engineered are totally mind blowing! I have also worked on many machines that I could have hunted the designer down and beat him half to death! All in all though, the job is very rewarding and the pay aint to bad either! I wish I would have followed my friends advice though. He and I started work together in the same field. The only difference was I stuck it out helping design, debug, and maintain such equipment for someone else. He got out after he learned the trade and started a small pick and place company and at the ripe old age of 40 ended up retired, in Florida, and pursues his motorhead hobby by building racing machines. The guy sits on millions!
969863
There is also friction caused by the turning of the gears.  The pendulum need enough mass to overcome this.
249597
14 bolt is PLENTY strong!\n\nBut why not sell it to a 4 X 4 enthusiast, use that money to go towards a narrowed 9" rear?\n\nI question the availability of gear ratios for that particular style of rear...That's one of the reasons why more people  aren't doing what you are considering right now!  Also think about housing ends, brakes, axles with the proper bolt patterns, etc...
491336
A square rod that sits in a square groove on the side of a shaft used to keep something like a pulley or gear rotating solid with the shaft. You will find these used for attatching pulleys and sprockets to larger electric and small gas motors.
729580
I suppose your talking about High gear or Low gear.\n\nLets say 1-18.\n\nLower gears like 1-10 will be tougher to pedal. And are great for going up hills or getting a leg workout.\n\nHigher gears like 10-18 will be looser and easier to pedal. Great for flat surface or going down hill.\n\nSpeed is only a factor when the amount of force applied meets the momentum required to achieve the speed.\n\nIf your legs are strong enough in low gear you can push hard and move fast. If you've got some good cardio going, that you can really get moving in a high gear too.
980969
Having left side drive will only help if you grind on your right side. If you grind on the right side and have right side drive you are more likely to hit your chain and sprocket if you mess up while grinding. Other than that it doesnt have any other advantages than right side drive.
302113
Hmmmm, It looks like Mr. dmb06851's engineering class has been given some tough home work again. Well, I gave Jenny one so I'll give you one. Again, it depends on the saw style. A regular circular saw would most likely have a Spur or Helical gear in it since the arbor shaft is parallel with the motor shaft. How ever, in a "rip saw", that is still considered a household tool, will have a Helical/bevel/worm gear in it. That's right, A worm-gear drive shaft that's beveled(cone shaped) that rides on the beveled face of the driven gear. Dewalt uses a straight worm gear that rides on the outer circumference of the gear but Makita uses the helical/bevel/worm.
857978
Clockwork rely on spring tension to operate.  But when winding them, a ratchet prevents the spring from uncoiling from one end, so that it will instead push against the escape mechanism, which will slowly use the spring tension to drive the inner gears.\n\nAs for a site, you got me there.  That does not mean there isn't one, I just don't know of any specific one. But you can look what Leonardo Da Vinci did, that would be a good start.
1012971
The Browning Automatic Bicycle Transmission\n\nhttp://www.bsn.com/Cycling/articles/browning.html\n\nhttp://seattle.bizjournals.com/seattle/stories/2002/03/18/story7.html\n\nhttp://www.exn.ca/dailyplanet/story.asp?id=2002102269
96519
Probably for the same reason there are lowriders and chopped motorcycles...cuz they can. In my day it was cubic inches and horsepower. For the life of me, I can't figure out why someone would spend thousands of dollars to make a car jump around like the devil is behind the wheel. But I do admire the hard work and innovation that goes into making it happen. Don't ask why, admire the work and move on if it isn't for you. C'mon...some of them are actually pretty cool :).