Abstract: A fixed assembly includes a locking pin in a cylindrical configuration and formed with an annular recess. A movable assembly includes an interior sub-assembly and an exterior sub-assembly. The exterior sub-assembly has parallel side walls forming an exterior chamber. A first aperture passes through the parallel side walls. A hollow cylinder in the first aperture is aligned with the first aperture. The hollow cylinder is adapted to removably receive the locking pin. The hollow cylinder has a radial hole aligned with the annular recess when the locking pin is within the hollow cylinder. The interior sub-assembly has opposed plates forming an interior chamber. A lever is pivotably mounted within the interior chamber. The lever has an arcuate section rotatable between an advanced position into the annular recess to lock the locking pin. The arcuate section is rotatable to a retracted position withdrawn from the annular recess.