Hi guys n gals,Bit of a mystery for me so any ideas would be great. As we can see from the image to the left there is a rather heavy piece of glass being supported by 3 chains separated by approximately 120º each, thusly dividing the counteractive force by 3. So far so good. This will easily help with the tension on each chain so they don't snap. Problem is why are they all connected to the same point at the top, surely this would be best having 3 separate connections with the ceiling putting less stress on the ceiling. Maybe there is a plate-like fixture behind the ceiling which is fastened to the connecting points spreading the force out over a larger surface area. Any suggestions?
Martin Phipps
Image taken & edited by Martin Phipps in Docevita Café, Aston University.
Not sure if I should be commenting on our own blog but I'd guess it's because the light could hang at an angle if the chains were improperly fastened seperately, and that would just make tension on two or even one chain greater.
ReplyDeleteAlternatively it could just be to save roof space.
Tom Corbett
In theory you could have the three chains mounted seperately on the ceiling. Each ceiling mount would then only have to carry a third of the load.
ReplyDeleteFurther, if it was such that the cables were vertical, the tension in each would only be 1/3 Mg. When sitting at an angle as shown, the vertical component of tension still has to be 1/3 Mg, giving the total force in each cable as 1/3 Mg / cos a. Where a is the deviation from the vertical.
Bringing it to a single point is simply much more practical, even if the designer needs to consider heavier loading at both the mount and the chains.