Moreover, the machine regulations impose the fixing of suspended electrical panels with almost double dimensioning compared to the real weight: that is sheet thickness and bolts appropriately dimensioned to support a 65% more of the finished weight....otherwise a structure of support to the frame foot in order to "absorb" all the weight.
and where, of grace, is such a thing affirmed? What is machine regulations?
But I wanted to understand the most genuine problem, namely:
If I have to verify some m6 screws that fix an object of 100 kg , I do not have to verify the cutting screws but I have to multiply the weight for a friction coefficient (given by the two contact materials) to obtain the closing force necessary , then the closing force tot divides it for the num of the vines, and this value compares it with the yielding of the pulling screw.
Right?
first of all a question. Have you ever seen a life break? and instead have you ever seen a dowel parade from the wall, or the wall break?
the weak link of the chain must be checked, and if you have bolts to a wall, it is the wall the first to break. then you have to dimensional the dowel according to the masonry, not the screw. I think using m6 is like hanging clothes with the ball pins. I would not go under m12 rupture of the dowel during the screwing.
if you want to dimensional a bolting as if it were structural, then it proceeds like this:
- the weight to support is 'p'
- the friction force to support the weight 'p' will be fa = mu*p*k, where mu is the friction coefficient and k the safety factor (attrite)
- divide makes for the number of screws
- I find the screw whose section resistant equivalent 'a' (to look at catalog!!!) is such that: sigmay = does * k' / to where sigmay is the yielding sigma and k' is the safety factor (for yielding)
the screws that can be cut are only those with rectified stem, if the cutting work takes place on the rectified part of the stem. Of course, we're not talking about self-taxing. . .
Clear?
