2 Attachment(s)
Resolution of Forces and Moments on a machine structure
Hello,
I am designing a machine which is able to freely move through a total of 4x 1m long guide rails (each have 2 linear guides).
I have attached a link to the guide rails:
[ATTACH]2238[/ATTACH]
My concern is the total moment on each of the guide rails, depending on the direction the guide rails allow around 670nm of moment. However, since I am using several rails I am confused as to how the forces/moments are distributed between the rails and guides. Please see below:
[ATTACH=CONFIG]2239[/ATTACH]
The diagram above contains a side view of the machine. The squares (1,2,3 and 4) are pads which mount the linear guides shown in the link (the guide rail I am using is the WS-20-80-15. The machine is free to move in the direction of the force marked 'F', however where a Driveshaft protrudes from the bottom of the structure, A reaction occurs, 'R', which I am assume is equal and opposite to F. There is also a Weight force, W, which acts through the center of mass. The weight of the machine is 800Kg. For arguments sake, take F and R to be 1000N.
If I wanted to calculate the moment about (1), the linear guide in the left hand corner of the machine, would the moment be as follows:
(Assuming ACW is positive)
M (1) = (F * 0.535m) - (R * 1.127m) + (W * 0.4145)
Assuming Weight = 800KG and F = R = 1000N, then M (1) = 1275.1 (Nm)
Here is what I am confused about. The guide rails are mounted in the exact positions on BOTH sides of the machine, so in essence, at point (1), there are two guide rails, one on either side of the machine. Does this mean the moment is shared between them, and hence, halved? Or does this moment act on BOTH of these guides rails at position 1?
These guide rails only have about 670Nm moment allowance. However, with two of them, should they be able to take 1340Nm at point (1)?
In addition, will the total weight, 800KG, act on (1)? Or, will the weight be distributed by the 8 linear guides and then act as a moment on (1)?
Is there a more accurate way of calculating this? I appreciate this is quite a simple problem!
Please advise me, any help would be very much appreciate.
Thanks
Rhys