Hello
For a personal project I want to size a threaded rod that will be used to mount and unload a load through a chisel-type mechanic see diagram attached
The question is how to calculate the real force on the horizontal threaded rod at the bottom of the chisel?
My diagram not being very clear I managed to find a better diagram on French see attached
Personal project with a load of 2t, hmmm...
Indeed I can be put a coef 4 which is oversized I am on a real load at 500kg
For this type of equipment
The problem is I think
1) The threaded rod must be non-outgoing
so blocked at the back and front so that the rod always remains internal to the base it will avoid twisting this said threaded rod
what happened from a sure source, if only by putting my foot on it among other things
so it's the tapped part that will take over all the effort via the step
For the type of threaded rod look at the crick of your car and the type of thread in general it is trapezoidal
@+
Hello
First of all, and I apologize in advance: here is a big bucket of ice water but I have a dry and warm towel at the end to comfort you
Solidworks will be of no use in calculating your table. BAM !!!! nose! pouffe! badaboum except conditions.
You have to do:
1°) calculations before starting the design
2°) define the maximum height of elevation and by the same token the length of the arms (the heavier and higher it is, the longer the bars should be).
The forces will give you the bar sections to use.
When the theoretical calculations are done as well as your realization with the right materials, the right axes; the right sides and spacers (dimensions and materials) and your assembly will be finished: then and only then can you make a finite element simulation with SolidWorks that will validate your theoretical calculations.
When you say that you are on a load of 500 kg, you should know that when you are in the low position, the efforts will be much greater.
For example, for a table with a running height of 600 mm and for a load of 500 (5000N), the force on the screw will be 15261N.
It is not enough to say that I put 2 tons (i.e. 56680 N) to guarantee a safety factor of 4 because the forces are not linear, which would mean unnecessarily oversizing your table. The coefficients are made on the weakest elements.
Note: as indicated by @GT22 forget about the threaded rod and go through a trapezoidal screw with a bronze nut at least. Moreover, @Stefbeno still has his hair straight on his head given the figures announced.
You must be thinking that zozo_mp is very bad to talk like that and well no, because I have a magic spreadsheet that allows you to calculate everything in excel (because it is fully customizable) before starting to draw any part in SW (these are the theoretical calculations that should be done before any design).
It was designed by a good friend of mine on another forum. He even made several sheets according to the number of bars (4 bars, 8 bars or more).
Kind regards
PS: look at the price of a second-hand table, before embarking on such a realization because the announced weight shows an achievement that is not within the reach of a pure amateur. Unless you do everything as I said and you already know a lot about industrial mechanical design.
Hello and thank you all for this feedback, indeed as far as the design is concerned, I don't start anything because I prefer to first size the most critical element, namely the trapezoidal screw as well as the pivot pins, for the latter it's simple shear, that's why I didn't have any problems, but for the screw it's getting more complicated I am interested in any Excel calculation note that can size the said screw
Hello
It is not necessarily simple shear because depending on the weight you have better have mortise tenon which makes your efforts in screed.
For the Excel sheet you will find it attached for free: but on the other hand you have to thank my friend Mecano41 who did a great job. (otherwise like in mission impossible the sheet will self-destruct within 10 seconds and you'll have the red of shame on your face ;-) )
Kind regards
@gt22 for having often addressed this subject on another forum and as we see in the link for 300 euros you have the new table so why try to do it even it will cost double or quadruple if you don't machine everything in wig and you buy (in china) only the screw and the nut in bronze.
Kind regards
Wow, pretty, we can even move the table!
Thank you Zozo_mp for sharing this work.
And congratulations to your friend Mecano41.