Patent ID: 8979098
Filing Date: 2015-03-17
Classification: B62B

Abstract:
1. A collapsible platform truck comprising: a platform; a pair of wheel-connecting bars rotatably attached to a bottom of the platform; a plurality of wheels connected to the wheel-connecting bars; a handle assembly having a pair of lower vertical frame members, a pair of handle arms telescopically attached in the vertical frame members, and a central grip joining the handle arms; two respective pivot pins; a pair of pivot brackets each having one end secured to a respective one of the vertical frame members, and the other end pivotally connected to a respective one of the wheel-connecting bars by means of a respective one of the pivot pins; a handle release and locking mechanism disposed in the handle assembly and having an actuator configured to be operated to allow the handle arms together with the central grip to displace with respect to the vertical frame members among a first extended locking position, a second retracted locking position, and a third retracted unlocking position where the handle assembly is unlocked and allowed to pivot between a generally upright position and a generally horizontal position generally flush with a top surface of the platform; a pair of first gear members connected to the handle assembly; and a pair of second gear members meshing with the first gear members and connected to the wheel-connecting bars; wherein when the handle assembly is in the horizontal position, the wheels are folded up underneath the platform and lie horizontally with respect thereto; and when the handle assembly is pulled away from the platform to the upright position, the first gear members engage and turn the second gear members, resulting in the wheel-connecting bars rotating to fold out the wheels from underneath the platform toward an eventual perpendicular position with respect to the underside of the platform; and wherein each of the wheel-connecting bars includes an outer tube and an inner tube inserted in a front end of the outer tube; the outer tube defines at its front end a pair of opposed arc-shaped slots in a periphery thereof; the inner tube defines a pair of opposed pivot bores in a periphery thereof; and each of the pivot pins is secured on the respective pivot bracket and passes through the opposed arc-shaped slots of the outer tube and the opposed pivot bores of the inner tube in such a manner that the outer tube is rotatable in a range of about 90 degrees with respect to the inner tube.