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Rotary transmission with linear guidance

Rotary transmission with linear guidance

Rotary transmission with linear guidance

HI all,

My background isn't in engineering so please excuse any ignorance. I'm Designing this mechanism driven by two powerful DC motors to automate the goal keeper on a Foosball table.

For obvious reasons I'm trying as hard as possible to keep the inertia of the moving parts as low as possible. With this in mind I designed the system the system below but I'm having a hard time finding the ball spline shaft that allows the linear guidance whilst providing the rotary drive for the kick.

The quote came in at 450euro which is a little over my budget. THK Ball Splines Model SLF
So my questions are;
Is there an obvious and simpler alternative which I'm missing?
If not, is the shaft pictured below the appropriate solution?

Any further input is highly appreciated.

PS: Ignore the frame, it's WIP

RE: Rotary transmission with linear guidance

You could probably save money by renting an engineer.

Mike Halloran
Pembroke Pines, FL, USA

RE: Rotary transmission with linear guidance

That's not a helpful answer!

The mechanism is fairly simple, I'm just looking better alternatives should there be one.

RE: Rotary transmission with linear guidance

Since you only need about 120 degrees of rotation you could use one segment of a geneva wheel with a long "pin" for the driven wheel to slide along. The motion ratio (slow-fast-slow) might be advantageous for accelerating the shaft smoothly.

je suis charlie

RE: Rotary transmission with linear guidance

Fantastic, many thanks!

@gruntguru That's an ingenious solution, as you said the non-linear acceleration may would contribute towards the kick. Am I right in guessing it reaches it's peak when the pin is closest to the center of the geneva wheel?

RE: Rotary transmission with linear guidance

Max velocity at the centre point. (assuming constant input velocity) Acceleration will peak somewhere between start and centre point and goes negative after centre.

je suis charlie

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