Patent ID: 8002242
Filing Date: 2011-08-23
Classification: B66F

Abstract:
1. An extension rod unit comprising: an outer tube and an inner tube which has a first end retractably inserted into an open top of the outer tube, a space defined between the outer and inner tubes, a fixing part located on the first end of the inner tube and located within the outer tube, two support boards connected to a second end of the inner tube and a lower end of the outer tube; a ratchet unit connected to the open top of the outer tube and including a connection member, a shaft extending through the connection member and an end of a lever, the connection member including two side panels and each having a first lug extending therefrom, the lever having two second lugs and the shaft extending through the first and second lugs so as to pivotably connect the lever to the connection member, two ratchet gears located between two sets of first and second lugs, a slot defined axially through the shaft, a first engaging plate located in the connection member and biased by a first spring so as to be engaged with the ratchet gears, each of the two first lugs including a recess and a notch, the lever including a second engaging plate movably connected thereto and the second engaging plate biased by a second spring so as to be engaged with the ratchet gears, the second lugs each including a push part; a driving member having a first end fixed to the fixing part and a second of the driving member extending through the slot of the shaft and located beyond the outer tube, and when the second engaging plate is positioned in the recesses of the two first lugs of the connection member, the first and second engaging plates both are engaged with the ratchet gears, the inner tube is moved in a direction away from the outer tube by pivoting the lever, the first engaging plate prevents the ratchet gears from rotating reversely, when the second engaging plate is positioned in the notches of the two first lugs of the connection member, the first engaging plate is disengaged from the ratchet gears by the push parts so that the first and second engaging plates both are disengaged from the ratchet gears, the inner tube is freely moved relative to the outer tube.