Abstract: The pivotal switching arm of a "swivel post" type load break switch carries, in addition to a blade contact, a U-shaped sliding block type conducting driver which has an elongated elastically expandable slot that engages the ratchet head of the rectilinearly movable switch pin of a current quenching device mounted on the fixed contact post. To control the spring constant of the slot, an enlarged opening is provided at one end of the slot which reduces the cross-section of the driver. At the other end of the slot, an enlargement serves to release the ratchet head when the switch opens. The driver enables rectilinear quenching devices to be used in conjunction with the curvilinear motion of the switching arm.