Tool connecting rod

A tool connecting rod, comprising:

• a barrel, having a first end and a second end, the barrel defining an axial hole penetrating the first and the second ends of the barrel axially, the axial hole defining a first receiving space corresponding to the first end of the barrel and a second receiving space corresponding to the second end of the barrel, the first receiving space defining a guide groove extending toward the second receiving space, the guide groove having an inner wall extending axially, the inner wall being formed with a first stepped portion, the first stepped portion having at least two stepped recesses;
• a rod, slidably received in the axial hole of the barrel, the rod comprising a first section and a second section, an end surface of the first section of the rod being formed with a receiving hole axially, an outer surface of the first section of the rod being formed with at least a through hole radially communicating the receiving hole,
• a resilient unit, comprising at least a pushing member and at least a limiting element, the pushing member having a body portion, an outer surface of the body portion having a second stepped portion, the second stepped portion being formed with at least two stepped recesses, the pushing member being slidably received in the receiving hole of the rod, the limiting element being received in the through hole of the rod, an outer side and an inner side of the limiting element selectively abutting against one of the stepped recesses of the first stepped portions and one of the stepped recesses of the second stepped portions, so that the pushing member is slid and limited;
• and a retainer, limitedly slid along the guide groove, a front end of the retainer being formed with two clamping portions, the clamping portions being capable of elastically moving inward, the retainer being disposed between the end surface of the first section of the rod and the pushing member, such that the retainer and the rod are in an operative relationship.