7 point hinge system (not a parallelogram)

7 Point Hinge System

The 7 point hinge system is to be used in a sheet metal folding machine.
As can be seen in the main picture below, the top section of the machine will clamp down
on the material and using hydraulic rams, the hinge will expand, rotating the folding edge
around the origin point causing the material to fold to a specific angle.




Through pure trial and error I have narrowed the solution down to be within a 2mm
tolerance, but for the hinge to work effectively, it needs to rotate around the origin point
with 0 tolerances.
Using parallelograms I know I can rotate the folding edge around the origin perfectly, but
this solution will only enable the hinge to operate up to approximately 90 degrees before
the pivot points begin overlapping, which can not happen when manufactured.
The folding edge needs to be able to fold to 130 degrees.




I'm not sure if there are equations or graphs involved in determining the placement of the
pivot points, or if it's a simple solution.
The problem I put to you, involves calculating where the pivot points need to be in order
for my hinge system to work. If the solution lies within a formula or graphs, the scale the
hinge is drawn at will not matter. Other wise, approximate values can be seen on the
drawing.
Any help would be gratefully received. Thankyou.
My e-mail is tagardiner@hotmail.com or swieng@bigpond.com

7 Point Hinge System

The 7 point hinge system is to be used in a sheet metal folding machine.
As can be seen in the main picture below, the top section of the machine will clamp down
on the material and using hydraulic rams, the hinge will expand, rotating the folding edge
around the origin point causing the material to fold to a specific angle.




Through pure trial and error I have narrowed the solution down to be within a 2mm
tolerance, but for the hinge to work effectively, it needs to rotate around the origin point
with 0 tolerances.
Using parallelograms I know I can rotate the folding edge around the origin perfectly, but
this solution will only enable the hinge to operate up to approximately 90 degrees before
the pivot points begin overlapping, which can not happen when manufactured.
The folding edge needs to be able to fold to 130 degrees.




I'm not sure if there are equations or graphs involved in determining the placement of the
pivot points, or if it's a simple solution.
The problem I put to you, involves calculating where the pivot points need to be in order
for my hinge system to work. If the solution lies within a formula or graphs, the scale the
hinge is drawn at will not matter. Other wise, approximate values can be seen on the
drawing.
Any help would be gratefully received. Thankyou.
My e-mail is tagardiner@hotmail.com or swieng@bigpond.com