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Participant

Join Date: Dec 2017
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Mechanical Hand Lever to Screw

12/07/2017 1:15 PM

Hi Guys,

I need some help with coming up with a way to take a mechanical lever(160mmtall) that pivots from the middle and travels back and fourth 45deg each way by hand operation, and turns a 8mm gear 1.5 turns roughly each way(3 turns from left to right), Any advice would help

Thanks Brodie

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#1

Re: Mechanical Hand Lever to screw

12/07/2017 1:30 PM

Have you not considered the use of a linear gear with a bevel gear (rack and pinion)?

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#3
In reply to #1

Re: Mechanical Hand Lever to screw

12/07/2017 2:14 PM

This is why sleep is a good idea, solved my little 3am dilemma Thanks!

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#4
In reply to #3

Re: Mechanical Hand Lever to screw

12/07/2017 2:23 PM

I had very little sleep last night, cat kept waking me up, and wanting out of Shroedinger's box.

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#2

Re: Mechanical Hand Lever to screw

12/07/2017 1:35 PM

Maybe a combination of a lever and spring loaded pulley system....

The lever turns the larger wheel that turns a smaller wheel....or you could go electromechanical with switches and motors...

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#9
In reply to #2

Re: Mechanical Hand Lever to screw

12/07/2017 3:12 PM
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#5

Re: Mechanical Hand Lever to screw

12/07/2017 2:23 PM

Well, you need a 12:1 ratio, a gear train between the lever shaft and the output gear, probably 2 stages, 4:1 ratio, and 3:1 ratio. Ratios are determined by number of teeth, e.g., from the set below, 32:8 and 24:8.

https://en.wikipedia.org/wiki/Gear_train

There are hobby stores that sell gears and stuff to robotic enthusiasts...

http://hobbymasters.com/hobbymasters-assorted-small-plastic-gear-set-16pcs/

Description:

2 each of 8 different gears.

All fit 2mm shafts:

18T spur gears 10mm diameter

20T spur gears 11mm diameter

24T spur gears 13mm diameter

32T spur gears 17mm diameter

35T spur gears 19mm diameter

56T spur gears 29mm diameter

8T pinion gears

12T pinion gears

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#7
In reply to #5

Re: Mechanical Hand Lever to screw

12/07/2017 2:29 PM

Do you know when it is time to change gears?

It is time to change gears when the tooth sizes don't match.

Corollary: There is always room for one more gear.

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#12
In reply to #5

Re: Mechanical Hand Lever to screw

12/08/2017 10:41 AM

"... from the set below, 32:8 and 24:8..."

The set pictured appears to be 32:10. I watched for a while to see if it morphed from 32 to 24 and perhaps 10 to 8 as well. No such luck.

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#6

Re: Mechanical Hand Lever to screw

12/07/2017 2:28 PM

So, given a 45° input, you wish to drive an output of 450° (a factor of 10). You could mount a 60-tooth sprocket on the input shaft (pivot) and a 6-tooth sprocket on the driven gear shaft, with roller chain connecting them. 60/6 is only for conversation. Any number of combinations would work, as long as it's a 10/1 ratio.

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#8

Re: Mechanical Hand Lever to screw

12/07/2017 2:42 PM

Oops! my bad. It's a 12:1 ratio, not 10.

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#10

Re: Mechanical Hand Lever to screw

12/07/2017 3:46 PM

Does the pivot point have to be half way up the lever:-

If you make the ¼ gear at the bottom of the lever 48mm diameter, and allow the lever to rotate about the centre of that gear you're done.

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#11

Re: Mechanical Hand Lever to screw

12/07/2017 3:55 PM
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