Gear Design 1

[delimashare]

Hi Everybody,

I have to design 3 gear assemblies which run a switchgear inside an enclosure. Here I attach a drawing for one gear only(for a similar project). I have to do my calculations and select the diameter, length, cross section, material...etc. for the linkages, shafts, axles, chains, ball joints and frames. Dimensions shown on drawings have to stay the same because they are related to the enclosure dimensions.
I was provided with the following information:

The linkage is tested at 5000 Lbs (1100N).
For this Torsion bar manual operator, the force is 250 N min and 450 N max.
Any information will be helpful.I need to start somewhere.

Thanks in advance.
Delimashare

 

[desertfox]

hi delimashare

Yes I can see the file now.
I think your calculations are not correct, what I expected to see was 1280N X radius of gear wheel then to work the force out in S1 I was looking for

force S1= 1280N X radius of gear/(perpendicular distance
between line of S1 force
and pivot point of gear


Then work through the bottom half of the mechanism back to the handle again using the lever lengths of the mechanism.

desertfox

 

[delimashare]

Hi All,
desertfox,Thank You so much for you time and help.

1)The Linkage is welded to the gear and rotated by applying the force on the linkage itself. That's why I considered the linkage length to estimate the torque on the gear? If this is wrong what would be the force on the linkage(L1) on gear1?Don't we have to consider it?

2)and in your equation :
force S1= 1280N X radius of gear/(perpendicular distance
between line of S1 force
and pivot point of gear
I could'nt figure out the direction of (perpendicular distance).It makes an angle of how much with horizontal line or x axix????

3)And do we estimate torque on shaft S1 or not,I thought we don't,because it is only compression/tension forces on this shaft only???

delimashare

 

[desertfox]

Hi delimashare

perpendicular means at ninety degrees to the reference plane.
If you draw a line from S1, perpendicular to S1 and make sure it passes through the pivot point of the gear rotation and thats the distance you require for the calculation.

desertfox

 

[delimashare]

Hi all,
Thanks desertfox
I have a simple question here.Is the torque constant all through the system?I'm really confused.
delimashare

 

[desertfox]

Hi delimashare,
In answer to your question - no, the torque is not necessarily equal throughout your system. If you can wait another day I'll try and upload something that may help you.

Regards,
desertfox

 

[delimashare]

Thanks desertfox,
I really appreciate that.
delimashare

 

[desertfox]

Hi delimashare

I have marked and uploaded your earlier files to show you how to calculate the forces however I need to point out two things:-

1/ I have ignored the angle that S1 makes with the operating shaft on the righthand view of your original pdf post page 1.

2/ Looking at your mechanism righthand view of page 1 at items marked L2 J1 you might find that you have trouble in operating the switch as you will transfer very little torque to the switch with the link L2 in that position.

desertfox

 

[delimashare]

Hi desertfox,
I was in a vacation and had no chance to check what you have sent me.Now I'm back to work and will do that soon.
Thank you so much.
delimashare

 

[delimashare]

Hi Desertfox,
I followed your instructions to calculate the torque on the operating shaft.Suppose the Torque on the operating shaft was (Z).How do I calculate the force to be applied on the handle?
Regards,
delimashare

 

[desertfox]

Hi delimashare,
If you have now calculated the torque on the operating shaft, finding the force is quite simple. All you have to do is divide the torque on the operating shaft by the length of the handle.
For example, if Z is in Nm and your length of handle is Xm, then force f is equal to Z(Nm)/X(m).
Regards,
desertfox