Reel spring of magnetic tape cassette

Claim 1

In a magnetic tape cassette, a reel spring made of stamped resilient sheet metal, said reel spring defining, with respect to transverse first and second axial lines crossing at a crossing point, a shape comprising: an elongated parallelogram having a shorter diagonal coincident with said first axial line and a longer diagonal coincident with said second axial line, whereby said parallelogram is divided into four quadrants by said axial lines; a first cut-out in said parallelogram, said first cut-out formed in a first said quadrant, said first cut-out extending from the peripheral surface of said parallelogram to at least said second axial line, whereby said first quadrant has an indented shape; and a second cut-out in said parallelogram, said second cut-out formed in a second said quadrant, said second quadrant being opposite said crossing point from said first quadrant, said second cut-out extending from the peripheral surface of said parallelogram to at least said second axial line, whereby said second quadrant has an indented shape, whereby said first and second cut-outs are asymmetric with respect to both said axial lines and are symmetric with respect to said crossing point.