Hand tool

A hand tool comprising:

• a tubular casing extending along an axis, and having opposite first and second ends along the axis;
• a rod body extending along the axis, connected telescopically to said tubular casing, and having an enclosed end that is disposed in said tubular casing, and an exposed end that is opposite to said enclosed end along the axis and that extends out of said tubular casing via said second end of said tubular casing;
• and
• a holding unit including
• a tubular member that extends along the axis, that surrounds said rod body, and that has a proximal end connected to said second end of said tubular casino and a distal end opposite to said proximal end along the axis and distal from said tubular casing, said tubular member having an inner surrounding surface that has two frustoconical urging surface portions diverging respectively in opposite diverging directions along the axis,
• a pair of collar assemblies that are surrounded respectively by said urging surface portions, each of said collar assemblies including a ring member that surrounds and that is movable along said rod body, and a plurality of angularly spaced-apart balls that are embedded in said ring member and that are radially movable relative to said ring member, and
• a pair of resilient members that are disposed in said tubular member, each of said resilient members biasing a respective one of said collar assemblies oppositely of the diverging direction in which the respective one of said urging surface portions diverges such that said balls of the respective one of said collar assemblies are urged so be in frictional contact with said rod body and the respective one of said urging surface portions to thereby restrain said rod body from moving relative to said tubular casing oppositely of the diverging direction in which the respective one of said urging surface portions diverges;
• wherein, when each of said collar assemblies is moved in the diverging direction in which the respective one of said urging surface portions diverges against the biasing force of the respective one of said resilient members, said balls of the respective one of said collar assemblies are separated from the respective one of said urging surface portions and released from said rod body so that said rod body is permitted to move relative to said tubular casing along the axis.