Trans - force / product design

When using a ruler to cut or draw a line, the ruler sometimes difficult to hold its position. This is because the force caused by the uneven distribution. Therefore the use of arch shape design could be a solution for this problem. After the deformation of sheet metal, pressure transmitted to the two ends of ruler without changing the hand held position. So that to achieve accurate results when cutting or drawing.
In the other hand, when compared to traditional metal ruler use on a vertical wall,
Arch shape of the design can be given a more comfortable and flexible finger control