Design of wind up toys 1

[UVlight1]

I was looking at some wind up toys at a museum store. On the way home I got curious about how much energy could be stored in the spring and how that energy is best transmitted into different types of motion. (Obviously, I am not a mechanical engineer...) I was thinking it might be fun to try design something with a wind up mechanism but in some type of high tech way. I suspect most toy mechanisms are made out of cheap materials, probably have high friction etc. So, how much would the energy density improve if high tech materials and tolerances were used?It is a kind of open ended question. I was wondering if anyone on this forum could recommend any books or websites that might be related to wind up toy design or other mechanisms. I am having trouble finding stuff at a reasonable level.

 

[Hoxton]

Might be better posted or linked to "engineers with hobbies" forum or "engineering history"

I once had a wind up gramophone motor, complete with a fly ball governor as a speed regulator.

Seemed to have loads of energy - wonder how much? Wish I still had it.

 

[3DDave]

Watches and clocks are also wind-up mechanisms, and they are very efficient. Many of the toys use Delrin/Acetyl resin which is a very low friction material. Toys will use lower reduction/higher power versions though the amount of energy stored in clocks can still be high. A weight driven standing clock has around 10 ft-lb of energy** for 24 hours of operation.

Check

https://www.google.com/?gws_rd=ssl#q=clockwork+mechanisms+for+toys

If you want an idea of the energy stored, the input energy is torque*angle with angle in radians. You'll need a torque meter; there are many ways to measure it.

For small torques, measuring the twist of a torsion rod is easiest.

Torque = angle*JG/L where J is the polar moment of inertia and G is the shear modulus, and L is the length of rod being twisted.

See

http://www.engineeringtoolbox.com/torsion-shafts-d_947.html

Torsional Deflection of Shaft for more info

I just bend a 90 degree portion on the end of the rod to give a reference for the amount of turn and to give a place to grab. A second wire is attached to the item being torqued, but no load is applied to it. Instead a dial can be added for measuring the angle.

**Here is some with a clock, more curious than I:

http://www.rfcafe.com/miscellany/homepage-archive/2014/potential-energy-pendulum-clock.htm

 

[tbuelna]

Designing and building wind-up mechanical toys sounds like a fun hobby, assuming you have lots of free time and a bit of extra cash.

From your profile it appears you are an electrical engineer, so it should be no problem for you to learn the basic mechanical principles (gears, springs, linkages, etc) needed to design these toys. There are even many online sources where you can purchase most of the small mechanical components needed, including clock springs.

A conventional metal clock spring is still a very efficient way to store energy. I can't think of any high-tech material that would perform better for this application. However, it might be fun to look at using other ways to store energy, like a compressed air system.

Good luck with your project.
Terry

 

[JED2007]

If you get a toy designed consider making a 3D printed model using the

http://www.shapeways.com

website. It's pretty simple to have something made once you send them a design model in a format they use. They make parts using several different types of metal now. I see mostly jewelry for sale on the Shapeways web site; a toy would be very much appreciated.

 

[KENAT]

I'm guessing this guy must have worked it out at some point

http://en.wikipedia.org/wiki/Trevor_Baylis

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