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19 votes
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Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?

I found that on some Spanish lines, the kinetic energy during braking is converted to electricity and used by other trains from the same line (research paper), but why not keeping the mechanical ...
Transistor's user avatar
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11 votes

Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?

On the London Underground, many stations use gravity. The line runs uphill into the station, and then departs downhill. This gives a large amount of energy storage, for free, with no additional moving ...
Neil_UK's user avatar
  • 405
7 votes

Can I weaken a coil spring consisting of spring steel?

You could try a bath of concentrated acid. As long as you could maintain circulation so the concentration was fairly constant, a spring presents a very uniform cross-section and should be dissolved at ...
Gonzonator's user avatar
7 votes

Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?

Note also that springs are subject to eventual (and very sudden) failure as they develop cracks with age and a very sudden 5.6MJ energy release inside a railroad car would be exceptionally dangerous!
niels nielsen's user avatar
6 votes

Why aren't counterweights used more for garage doors?

Seems like to me the reason is a counterweight provides a constant offset to the door weight and that weight changes as the door is brought back to horizontal. I suppose there would be a way to design ...
Jon Liebermann's user avatar
6 votes

Why aren't counterweights used more for garage doors?

I’ll be installing a custom counterweight for my new garage door – it requires some clever engineering to make it work since a residential garage door doesn’t have a fixed weight: its track bends ...
Kuba hasn't forgotten Monica's user avatar
6 votes
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How does load force impact load inertia?

Let's first compute the model. The control design is a separate effort. The torque applied to the drum is $n T_M $, where n is the gear ratio and $T_M$ is the output produced by the motor. $T_M= K_T ...
Suba Thomas's user avatar
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5 votes
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How to calculate tensile strength of braided steel wire?

First off, the tensile strength is a property of the material, not the spring itself. Strength, often denoted as $\sigma = F/A$, can be considered how much force a material can withstand for a given ...
BarbalatsDilemma's user avatar
5 votes
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Spring degradation in hand grip trainer

for a properly-designed (right materials, right size, right manufacture) spring of that type, the applied stresses are far too small to cause any plastic deformation (permanent bending) at all. ...
niels nielsen's user avatar
5 votes

Why do springs get harder to compress?

There are different designs of springs, with different properties: Constant Force Springs - Constant Force Spring Design Theory (2nd Source) The extension type of constant force spring represents ...
Rob's user avatar
  • 509
5 votes
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Questions about newton metre units

N/m or Nm$^{-1}$ is the correct unit of a spring constant and it's already in SI units. Nm or N*m on the other hand is the unit of a torque (or moment) and is also in SI units. So no, Nm and Nm$^{-1}$ ...
am304's user avatar
  • 1,841
5 votes

Mechanical mechanism that regulates gear's rotational velocity

To my understanding the Hartnell governor is a variation that might be applicable to your needs. Figure : HArtnell Governor source mechoholic Essentially it moves the sleeve against a compression ...
NMech's user avatar
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5 votes

Mechanical mechanism that regulates gear's rotational velocity

There are multiple things going on here. Your question indicates you have a variable input speed but want a constant output speed. The answer to this on its own would be a continuously variable ...
Tiger Guy's user avatar
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4 votes

How does load force impact load inertia?

Stretch in the spring delta $ Y = A.sin(\omega.t) = A.sin\sqrt(k/m) . t $ So the delta Y is not constant but if you are interested in delt Y_max delta $Y max = m/k$, by Hooks law. Because your ...
kamran's user avatar
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4 votes

Why aren't counterweights used more for garage doors?

The reason counter weights are not used anymore is due to a couple factors. The limited space like they mentioned in the above comments but the main reason for smaller residential garages the added ...
Canadoor. Tbay's user avatar
4 votes
Accepted

Quick release for spring-loaded rod

The force which is needed to pull the pin out, will depend on the friction of the pin and the neighbouring material, and the surface at which the friction works. Let's assume a friction factor $\mu$ ...
Bart's user avatar
  • 1,194
4 votes

Is strain energy the same as potential energy, or something differen?

This has been asked and answered numerous times before: https://www.quora.com/Why-is-strain-energy-equal-to-1-2*force*displacement-What-about-the-remaining-half basically, it's because you're ...
Jonathan R Swift's user avatar
4 votes

Can I weaken a coil spring consisting of spring steel?

By "strength" do you mean stiffness/modulus? The modulus does not change with tensile or yield strengths. Make it with wire of 1/2 the diameter for 1/2 the modulus. Acid will hydrogen stress crack ...
blacksmith37's user avatar
  • 6,162
4 votes
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How to mechanically attach a compression spring to a flat surface

It might seem simplistic, but if you have the option, you can drill a hole with a diameter slightly less than the spring and then pressure fit it inside the spring.
NMech's user avatar
  • 24.4k
4 votes
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What is the purpose of dead coils in the middle of a compression spring?

The dead coils on the ends of the spring furnish an (almost) flat surface, perpendicular to the spring axis, for the spring to engage the mating parts with. The dead coils in the middle effectively ...
niels nielsen's user avatar
4 votes

Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?

Mechanical energy recovery has been tried on rapid-transit systems, in the form of flywheel storage. This is known as KERS in the motorsport world, but usage on a railway requires much higher ...
jayben's user avatar
  • 451
4 votes

What wire are mechanical keyboard switch compression springs made of?

Spring properties in steel has to do more about heat treatment than the type of steel. It is true that certain types of steel have more potential to make better springs but only with the appropriate ...
DKNguyen's user avatar
  • 5,651
4 votes

How are springs that are designed for 100% extension different for ones that are designed for 60% extension?

For a given free length and spring rate there are an infinite number of designs of coil spring. However, there are many practical limitations that limit the options. A spring with a few coils, of thin ...
Greg Locock's user avatar
3 votes

Are spring constant and rate constant the same thing?

Spring rate can be specified either for a whole spring or per unit length which is often more convenient if you are buying spring stock to cut to length. The constant of a whole spring is force per ...
Chris Johns's user avatar
  • 15.2k
3 votes

How to push an endoscopic camera upto 20 meters in a horizontal pipe?

You can buy endoscope or borescope cables which should "just work," though 20m is longer than the typical cable you will find on Amazon or Ebay. If you want to try making your own, look at the design ...
alephzero's user avatar
  • 12.6k
3 votes

How to push an endoscopic camera upto 20 meters in a horizontal pipe?

Most electrical engineers use an electrician Conduit Ducting wire for that (which you could use in your cable setup), but in your case it probably easier to use a piece of string and a vacuum cleaner. ...
Rolf Huisman's user avatar
3 votes

Can I weaken a coil spring consisting of spring steel?

Probably just another hypotetical idea: If you squeeze the wire from circular into a square shape, it will have about 54% of the original rate. If you squeeze it slightly more into a rectangle, it ...
Ingo's user avatar
  • 171
3 votes

Can I weaken a coil spring consisting of spring steel?

Another hypothetical way to reduce the amount of material in the spring would be to fix it in a jig stretched to double its normal length. Then, heat it sufficiently to anneal it and remove the ...
alephzero's user avatar
  • 12.6k
3 votes

Questions about newton metre units

There are seven fundamental SI units (seconds (time), metres (length), kilograms (mass), ampere (current), kelvin (temperature), mole (amount of substance) and candela (luminous intensity) - https://...
Flydog57's user avatar
  • 131
3 votes

Choosing a Constant Force Spring

Provided your calculations are correct (you are not mentioning the mass that you will be launching) then you are right you need nothing more. However, I am not sure if its easy to find a constant ...
NMech's user avatar
  • 24.4k

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