You have a square glass panel with 24 cm sides and a ring with 5 cm internal diameter.
Cut the glass in 4 identical pieces such that you can slide them through the ring.

The ring's edge diameter (thickness) does make a difference. The ring will rotate 90 degrees at the corners with a pivot point at the center of the rings edge, not the inside corner of the glass.

What also makes a difference is the thickness of the glass. A thick piece of glass will not fit through as well as a thin piece. Assuming that the glass edges are unfinished, let f be the deflection between the glass & the ring where R is the ring's inside radius and t is the thickness of the glass:

          f = (R - sqrt(R^2 - t^2))/2

The formula to find the maximum ring thickness (d) is

          d = 2(2R - (f + 3)sqrt(2) - f)(sqrt(2) + 1)

          d = 2(R - (R - sqrt(R^2 - (t^2)/4) + 3)sqrt(2) + sqrt(R^2 - (t^2)/4))(sqrt(2) + 1)

When t = 0 cm, d = 3.657 cm

When t = 1 cm, d = 3.068 cm

Posted by Brian on 2005-07-12 16:27:09