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 ...
- 10k
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 ...
- 405
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 ...
- 81
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!
- 14.1k
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....
- 3,575
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 ...
- 1,911
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 ...
- 1,220
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
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 ...
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 ...
- 4,720
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 ...
- 1,035
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 ...
- 6,386
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 ...
- 11.4k
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. ...
- 14.1k
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 ...
- 515
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$^{-1}$ ...
- 1,831
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 ...
- 24.2k
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 ...
- 6,276
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 ...
- 11.4k
4
votes
Accepted
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 ...
- 7,804
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 ...
- 21.9k
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 $\mu$ ...
- 1,174
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 ...
- 7,662
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 ...
- 6,102
4
votes
Accepted
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.
- 24.2k
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 ...
- 14.1k
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 ...
- 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 ...
- 5,147
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 ...
- 528
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