One way ball screw 1

[rodrigonramon]

I am trying to find a one way ball screw to use on a machine I am building.

Basically what I would need is a small spring loaded ball screw with a good amount of threads to spin a motor.

Imagine a yankee screwdriver, but instead of focus on force and bi-directional movement,
a focus on spins and uni-directional movement.

I want a recurring movement to spin the ball screw causing the motion to spin a motor to cause a voltage.
Then when the pressure is released from the actuator, the ball screw would slide back up to starting
position and then begin to spin again when the force is reapplied.

I am not technically married to the idea, and any other suggestions to improve on this would be appreciated.
I also considered using a regular ball screw connected to a regular motor and then using a full wave
rectifier to fix the alternating voltage and create a DC voltage.

Ideas? Improvements? Flaws?

 

[gerhardl]

Am I getting the correct impression: You have a uni-directonal mechanical force for a certain periode of time, and then reacurring in a pattern. You want this force uni transformed to an electric current given an electrical pulse. (1)

Your idea is to use a kind of spring-loaded 'ball screw contraption' to do this, for instance spinning a dynamo (as an exsample), and then revert to start position by the spring force, to repeat from start.(2)

I understand you are reluctaant to diclose your total idea-concept, but some specifications may help: size and art of exsisting force, size limits of contraption, and limits for the electrical current :what do you need the current to do/perform ?

 

[rodrigonramon]

Gerhardl,

Yes. basically there is a repetitive pattern of unidirectional force and I would like to use this to power a motor for the duration of this force (and have it spin freely thereafter).

I am held back from sharing based on a confidentiality agreement.
The force can be expected to be in the range of 60-100N. The size of said contraption is very small. I would say I have a very small threshold around the ball screw and motor to work with. The use of this would be not to create a pulse, but a lasting voltage with which to charge a battery. (approx 33V)

A possible motor to work with is a the Maxon Powermax 30-200W

http://www.electromate.com/ftp/public/Maxon Product Catalogs/Maxon Catalog 2009-2010/180.pdf

Again, I am not limited by this idea in my design, and could take it away from the mechanical aspect and maybe move it towards pneumatics or something else.

Thanks for your interest!

 

[MintJulep]

All the mechanics seems very inefficient.

See "Shake light"

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

 

[tbuelna]

So you have a ball screw that is free to translate along its longitudinal axis but is constrained in rotation, and has an axial force applied to it by a preloaded spring. And this ball screw engages a ball nut that is constrained in translation but is free to rotate about its longitudinal axis, and is torsionally coupled to an electric generator. The coupling device between the ball nut and generator is a one-way clutch that allows the generator to overrun the ball nut when the travel limit of the ball screw is reached. Is this correct?

The first question I have is what provides the energy needed to drive the ball screw in the opposite direction and re-load the spring?

 

[hydtools]

Sounds like the old toy top I used to play with. Push a twisted metal shaft down into the top to make it spin. Pull the shaft out and push again.
Use a one-way clutch at the output end of the shaft.

Ted

 

[asimpson]

Dynamos work best at higher speed. I have seen device thet uses oscillating mechanicel movement to wind a spring until certain threshold torque is achived and spring releases torque spinning dnamo at optimum speed and elecrical energy harvested in battery.

You will have to consider speed/torque to harvest electrical power for which ever dnamo you choose. Don't think you will find solutinn that works efficiently in all circumstances.

 

[zeusfaber]

Is it essential for the motor and the linear motion to be coaxial? If not, you might consider turning the motor through ninety degrees and going for a rack, pinion and freewheel arrangement (with a bit of doubling-up on hardware, this could be made to extract work from both extend and retract cycles). No guarantee it would be more suitable, but it gives you an alternative you can compare your original plan with.

A.

 

[MadMango]

I designed a drive system similar to this. I used a ball screw with an offset motor and belt drive. There was a solenoid-controlled idler that kept tension on the drive gear and belt. When the carriage connected to the ball screw reached end of travel (hall sensor), it returned to the start position. The idler would retract and allow the ball screw to free-spin as required.

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