Hot answers tagged

19 votes
Accepted

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 ...
  • 8,794
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 ...
  • 406
8 votes
Accepted

Why aren't counterweights used more for garage doors?

It makes me wonder why some sort of counterweight system isn't used instead. I'd guess it's because residential garages are normally a bit limited on space and the counterweights need somewhere to go....
  • 3,587
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 ...
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!
6 votes

Metal spring thermal expansion

Assuming the spring is not fully compressed/bottomed out, it doesn't really matter if the spring material is expanding or not because it's a spring - it will deform to fill the space between the coils....
  • 3,535
6 votes
Accepted

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 ...
  • 1,876
5 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 ...
5 votes

How does non-electrical ATEX apply to springs?

This is not an authoritative answer as I don't know the ATEX regulation that well. You have it however right that the ability to form a spark is relevant here. So your next step would be to look at ...
  • 4,651
5 votes

What is the Technical Term for this kind of slot?

In the datasheets, this type of memory card socket is called "Push in, Push out", or simply "Push-Push". In contrast, the memory card socket that uses friction is called "Push in, Pull out". Keep in ...
  • 1,045
5 votes

Rotary energy storage mechanism

The mainsprings of mechanical timepieces provide an excellent example of how you can accomplish what you want. They are a type of torsion spring made from a metal ribbon which can typically be wound ...
5 votes

Rotary energy storage mechanism

Both a torsion bar and a "coil" spring do what you want. The torsion bar is intended for rotation of only a fraction of a circle, and generally has a high spring constant. The coil spring can be ...
  • 11.3k
5 votes

What is the simplest spring system that could produce recoil absorption comparable to that exhibited by the AA-12 assault shotgun?

There is a pervasive misconception that recoil can be "absorbed" by such things as springs and proprietary gas systems. This is not true; eventually all the recoil produced by launching the bullet ...
  • 2,989
5 votes
Accepted

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 ...
5 votes
Accepted

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. ...
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 ...
  • 410
5 votes
Accepted

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$^{-1}$ ...
  • 1,816
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 ...
  • 22.8k
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 ...
  • 4,923
4 votes

What are the lightest springs?

I know your question is about springs, but I don't think that springs are the answer to your desired application. As you mentioned, the inward force from air pressure is very large so not only do you ...
  • 5,960
4 votes

What is the [PVC] tube or foam in metal springs for?

I know of at least one case where such material was added inside the spring to dampen it. The spring will be resonant at some frequency. If there is enough component of that frequency in whatever is ...
  • 11.3k
4 votes

Spring - Piston with different extension and compression rate

The first design that comes to mind is a pneumatic cylinder with a large one-way valve and a slow two-way release on the back end. I've attached quick sketch below: The idea here is that the big ...
  • 161
4 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 ...
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 ...
  • 21.2k
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 $\mu$ ...
  • 1,164
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 ...
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 ...
  • 5,932
4 votes
Accepted

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 ...
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 ...
  • 421
3 votes

Would a double helix spring be more or less effective than two springs?

I think two equal springs would test very close to a spring with double the spring constant. See adding springs in parallel equation. Two springs may be somewhat less material efficient than a single ...
  • 7,499

Only top scored, non community-wiki answers of a minimum length are eligible