Vertical movement turning a gear

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Discussion Overview

The discussion revolves around the mechanical concept of converting vertical movement into rotational motion using a rod with gear teeth, exploring various mechanisms and designs to achieve this goal. Participants consider different approaches, including racks, cranks, and clutches, while addressing the challenges of maintaining consistent rotational direction.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests using a toothed rod (rack) to drive a gear wheel but notes the need for the rod to maintain contact with the gear.
  • Alternatives to a rack include using a crank, tape or cord on a drum, or a stepped rubber belt with an idler gear.
  • Another participant proposes using two parallel racks to control the direction of rotation by alternating engagement with the gear.
  • Discussion of using a ratchet or sprag clutch to allow movement in one direction while keeping a rack engaged is raised, but concerns about complexity and potential jamming are noted.
  • One participant expresses a desire for a mechanism that allows a shaft to turn in the same direction regardless of the rack's vertical movement, likening it to a motor piston.
  • Concerns are raised about the suitability of a rack-and-pinion system for driving an AC generator, with a suggestion that a consistent driving force is necessary.
  • References to external resources, including books and videos, are made to assist in understanding mechanical design concepts.

Areas of Agreement / Disagreement

Participants express various ideas and potential solutions, but there is no consensus on a single effective method to achieve the desired outcome. The discussion remains unresolved with multiple competing views on the best approach.

Contextual Notes

Participants mention limitations regarding the complexity of setups, the need for consistent driving forces, and the potential for jamming in proposed mechanisms. There are also references to the need for further understanding of mechanical components like clutches and cranks.

Who May Find This Useful

This discussion may be useful for individuals interested in mechanical engineering, particularly those exploring the conversion of linear motion to rotational motion and the design of mechanical systems.

abdo799
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i am still newbie , i don't even know if this question should go here or not , but i will ask it anyway.
I have a rod that moves vertically , i need use this rod to make a shaft turn. So i had an idea, what if i made this rod toothed and make it move a gear as it goes up , will that work?
if no , why?
 
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A straight rod with gear teeth is called a rack. It could drive a gear wheel on a shaft but would need to be held in contact with the gear.
Depending on the rotation angle required an alternative could be to use a crank.
Also consider a tape or cord on a drum. Maybe with an idler.
I would consider a stepped rubber belt running over a stepped pulley on the shaft, with an idler gear.
 
Baluncore said:
A straight rod with gear teeth is called a rack. It could drive a gear wheel on a shaft but would need to be held in contact with the gear.
Depending on the rotation angle required an alternative could be to use a crank.
Also consider a tape or cord on a drum. Maybe with an idler.
I would consider a stepped rubber belt running over a stepped pulley on the shaft, with an idler gear.

I am still in high school , so if you can give a site or a book or something so I can know what's an idler , crank and all those things , that would be appreciated
 
I checked what a crank means , I don't think I need it , I just need to make the shaft turn , later it will turn a wheel , another thing , if the rod moves up the gear will turn anti-clockwise if it moves downwards, the gear will turn clockwise , is there anything I could to make the shaft turn in one direction in both cases ( the shaft doesn't have to be connected to the main gear )
 
If you have two parallel racks joined and driven from one end, but with the racks on different sides of the gear, then the direction of rotation will be decided by which rack you engage with the gear. To travel continuously in one direction you must alternate between racks as they reciprocate.
 
A ratchet. Movement in one direction, but only in a single stroke. Would be notchy, but could be butchered from an old bicycle.

Or

Sprag clutch. Movement in one direction, again only on one stroke, and you can keep a rack constantly engaged.
 
@baluncore, your idea could work, but i can't use more than one rack
@xxchrisxx, what i meant is not that i want the gear to move in only one way , i meant if you know a combination of gears or something that can make a shaft turn in same direction despite of the movement of the rack, like a motor piston ( i know it works differently than a rack ) i moves up and down , but the wheel turns in one direction
 
abdo799 said:
@baluncore, your idea could work, but i can't use more than one rack
@xxchrisxx, what i meant is not that i want the gear to move in only one way , i meant if you know a combination of gears or something that can make a shaft turn in same direction despite of the movement of the rack, like a motor piston ( i know it works differently than a rack ) i moves up and down , but the wheel turns in one direction

I'm fairly sure you can do it with a series of clutches, but it'll be a total nightmare to set up so it doesn't jam.

But if you really want a smooth input, with the linear input driving in both directions.

VVVVVVVVV

I checked what a crank means , I don't think I need it

You'll need a crank.

This mechanism is basically a crank slider.
The problem with a crank is, you need to start it spinning the way you want and keep the momentum up. If not it'll jam at the top or the bottom, or go the wrong way.

Think a Railway Handcar.
 
xxChrisxx said:
I'm fairly sure you can do it with a series of clutches, but it'll be a total nightmare to set up so it doesn't jam.

But if you really want a smooth input, with the linear input driving in both directions.

VVVVVVVVV

.

I am going to connect a generator to the shaft, maybe if this going to be complicated , maybe it won't matter , the generator produces AC anyway , right ?
 
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arunsjunk said:
Perhaps the following book could be an inspiration:

https://www.amazon.com/dp/1603863117/?tag=pfamazon01-20


Instead of the rack and pinion described earlier, you can get uniform circular motion from a modified pinion. Here's a video of the design:




thanks, if you know any other book about mechanical design please tell me it's name ( preferred to be a book for newbies and not advanced )
 
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  • #12
this cute animated picture I enjoyed this thread so much that I want to add the first thing that came to my mind: Hey, these early steam engine fellows had the same problem !

Also a little bit because I wondered how it could be that this thread went off to pretty complicated stuff (lots of wear, etc.)

Re the AC generator: yes they produce AC (DC with a commutator or with a rectifier circuit). But they like some constant driving. A rack up and down might not be ideal, if the up and down is a sine.
 

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