Strap buckle assembly for clamping a strap

A strap buckle assembly (1) for clamping a strap (2) is disclosed which comprises a first and a second part (3, 4) for clamping the strap (2) in-between, wherein the first and the second part (3, 4) are relatively movable to each other, and an operating mechanism (5) having a spring (5b), wherein the spring (5b) is arc-shaped having a variable bending radius (R) and comprises a first end (5c) connected to the first part (3) as well as a second end (5d) connected to the second part (4), and wherein the operating mechanism (5) is configured to vary the bending radius (R) of the spring (5b) such that said first and second end (5c, 5d) of the spring (5b) are displaceable with respect to each other between a clamping position and an adjusting position.