Folding structure for trolley

摘要

A folding structure for a trolley includes at least two main poles and a movable member. The main poles are connected to a carrying platform having an operating rod, two roller sets, and a base that are motionally linked. A transverse plate is attached to upper ends of the main poles. The movable member is slidably mounted on the main poles and has a pull rod. The pull rod extends beyond the transverse plate for an extension distance. To prepare the trolley for use, the operating rod is pushed downward so that the roller sets expand in a horizontal direction and the base is laid down. Then the pull rod is set for its largest extension distance to facilitate a user's pulling trolley. After use, the trolley can be easily folded by lifting the operating rod that in turn drives the roller sets and the base to retract.

主权项

1. A folding structure for a trolley, the folding structure comprising:
at least two main poles that are spaced apart from each other by a preset distance, wherein a carrying platform and a transverse plate are separately mounted with the two main poles; and the transverse plate is provided with a pressing block, two retaining blocks, and a spring member, in which the pressing block has a receiving groove, the two retaining blocks each have one end provided with a ramp portion in contact with a respective one of two lateral sides of the receiving groove, and the spring member accumulates or releases an elastic potential energy in response to relative movement among the pressing block and the two retaining blocks; and a movable member located below the transverse plate and slidably mounted around the two main poles, wherein the movable member has two hooks extending therefrom and being configured to engage with the two retaining blocks; the movable member has a pull rod extending through the transverse plate and having a portion going beyond the transverse plate; and the portion of the pull rod that goes beyond the transverse plate has a length defined as an extension distance; wherein when the two hooks of the movable member each engage with a respective one of the two retaining blocks, the extension distance is at its maximum; wherein while, with the two hooks of the movable member each engaging with a respective one of the two retaining blocks, being applied with an external force, the pressing block presses against the ramp portions of the two retaining blocks so that the two retaining blocks come close to each other and thus are disengaged from the two hooks, thereby allowing the movable member to freely slide along the two main poles to change the extension distance; wherein the spring member accumulates the elastic potential energy while the external force is applied; and wherein the spring member releases the elastic potential energy to return the pressing block and the two retaining blocks once the external force is removed.