Patent ID: 6840142

Claim:
A socket wrench extension, comprising: an elongated rod, having one end having an inner wall formed with a circular receiving chamber and having a periphery formed with a first locking hole and a second locking hole each communicating with the receiving chamber; a drive rod, slidably mounted in the receiving chamber of the elongated rod, and having a first end formed with an oblique first retaining cavity communicating with the first locking hole of the elongated rod and an oblique second end formed with a second retaining cavity communicating with the second locking hole of the elongated rod; a steel ball, mounted in the first retaining cavity of the drive rod, and partially protruded outward from the first locking hole of the elongated rod; a control knob, mounted in the second retaining cavity of the drive rod, and partially protruded outward from the second locking hole of the elongated rod, wherein when the control knob is pressed, the drive rod is fully retracted into the receiving chamber of the elongated rod; an elastic member, mounted in the receiving chamber of the elongated rod, and having a first end urged on the second end of the drive rod and a second end urged on the wall of the receiving chamber of the elongated rod; a magnetic member, secured on the first end of the drive rod; and a control ring mounted on the outer wall of the elongated rod, wherein the control ring has an inner wall formed with an arcuate guide grove aligning with the second locking hole of the elongated rod for receiving the control knob, and wherein the wall of the arcuate groove of the control ring is moved to press the control knob when the control ring rotates.