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• # Rack and pinion lift

Discussion in 'Calculations' started by ahsaniftikhar, Sep 14, 2020.

1. ### ahsaniftikharNew Member

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Sep 2020
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Hello all,

I am trying to design a telescopic elevating platform based on a rack and pinion configuration. The design is based on this video from youtube (click the link here). The video shoes this in a horizontal configuration. I want to use this mechanism to build a vertical lift. For that I need to perform some calculations. The telescoping effect achieved by this mechanism is of practical use in compact applications. Can anyone please help me out with the calculations needed to size the motors and the size if the rack and pinon for this? Please see the diagrams attached to get a better idea of the problem. I am particularly stuck with the effects of friction in this system.

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3. ### shachmatNew Member

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Oct 2020
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Hello Ahsan,
I didn't understand why you're trying to use rack & pinion in your case. You can save money on complex manufacturing and "off the shalf" items by simply use a 3 wheels on each side and timing belt.

The rack & pinion can become relevant if you design a telescopic mechanism.

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Best regards.

QUOTE="ahsaniftikhar, post: 26391, member: 39748"]Hello all,

I am trying to design a telescopic elevating platform based on a rack and pinion configuration. The design is based on this video from youtube (click the link here). The video shoes this in a horizontal configuration. I want to use this mechanism to build a vertical lift. For that I need to perform some calculations. The telescoping effect achieved by this mechanism is of practical use in compact applications. Can anyone please help me out with the calculations needed to size the motors and the size if the rack and pinon for this? Please see the diagrams attached to get a better idea of the problem. I am particularly stuck with the effects of friction in this system.[/QUOTE]

4. ### s.weinbergWell-Known MemberEngineeringClicks Expert

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Nov 2012
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A. you talk about sizing the motor, but it looks like you are driving with a linear actuator, using the rack and pinion to effectively double your stroke. Is that the case?

B. There appears to be some kind of linear guidance system - as there should be, but I can't make out any real details. That would have a huge impact on your friction.

As far as sizing the rack and pinion, it's likely not critical, so long as your teeth are strong enough not to break. Any size would have essentially the same effect of doubling the motion of the final stage relative to the pinions

5. ### shachmatNew Member

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Oct 2020
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Can't agree more with what you wrote.
The rack and pinion in this case is Unnecessary.

And it's not a telescopic elevation, it just elevation.

6. ### s.weinbergWell-Known MemberEngineeringClicks Expert

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What the rack and pinion do is they effectively double the stroke. If you move the pinion by X, the end stage will move 2X.
That should work as intended in this design.

7. ### OilytrunkWell-Known Member

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Nov 2017
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Same thought, It is probably not a telescopic elevation.