Simplified fold-in-half wagon

A simplified fold-in-half wagon, comprising four corner columns disposed at four corners of the wagon, the four corner columns comprising a first corner column, a second corner column, a third corner column, and a fourth corner column sequentially arranged along a circumferential direction of a bottom frame,

• wherein the first corner column and the second corner column located at a front side of the wagon serve as two side rods of a front frame, and the third corner column and the fourth corner column located at a rear side of the wagon serve as two side rods of a rear frame;
• wherein each of the four corner columns is provided with a hinge base at a lower end, and the wagon further comprises a left side frame and a right side frame;
• wherein the left side frame composed of two parallelogram mechanisms that are arranged one after another in a direction from front to rear is provided between two of the hinge bases located on a left side of the wagon, the right side frame composed of two parallelogram mechanisms that are arranged one after another in the direction from front to rear is provided between other two of the hinge bases located on a right side of the wagon, adjacent inner ends of the two parallelogram mechanisms are hinged by an intermediate supporting base, outer ends of the two parallelogram mechanisms are respectively hinged to respective hinge bases, and each parallelogram mechanism comprises an upper connecting rod and a lower connecting rod arranged apart from each other;
• wherein four vertexes of each parallelogram mechanism are hinged about a first hinge axis, a second hinge axis, a third hinge axis and a fourth hinge axis respectively;
• wherein each hinge base is provided with a first upper support surface at an outer end of the upper connecting rod of a corresponding parallelogram mechanism and a first lower support surface at an outer end of the lower connecting rod of the corresponding parallelogram mechanism, such that at least one of the following is caused when the corresponding parallelogram mechanism is unfolded and arranged horizontally:
• the first upper support surface abuts against a lower surface of the upper connecting rod located on an inner side of the first hinge axis to prevent the upper connecting rod from swinging downwardly further during unfolding of the corresponding parallelogram mechanism, thereby providing unfolding support;
• the first lower support surface abuts against an upper surface of the upper connecting rod located on an outer side of the first hinge axis to prevent a tail end of the upper connecting rod from swinging upwardly further during unfolding of the corresponding parallelogram mechanism, thereby preventing further downward swinging of the upper connecting rod to provide unfolding support;
• the first upper support surface abuts against a lower surface of the lower connecting rod located on an inner side of the second hinge axis to prevent the lower connecting rod from downwardly swinging further during unfolding of the corresponding parallelogram mechanism, thereby providing unfolding support;
• and the first lower support surface abuts against an upper surface of the lower connecting rod located on an outer side of the second hinge axis to prevent a tail end of the lower connecting rod from upwardly swinging further during unfolding of the corresponding parallelogram mechanism, thereby preventing further downward swinging of the lower connecting rod to provide unfolding support;
• and
• wherein each of a front side and a rear side of each intermediate supporting base is provided with a second upper support surface at an inner end of the upper connecting rod of a corresponding parallelogram mechanism and a second lower support surface at an inner end of the lower connecting rod of the corresponding parallelogram mechanism, such that at least one of the following is caused when the corresponding parallelogram mechanism is unfolded and arranged horizontally:
• the second upper support surface abuts against a lower surface of the upper connecting rod located on an inner side of the third hinge axis to prevent the inner end of the upper connecting rod from downwardly swinging further during unfolding of the corresponding parallelogram mechanism to provide unfolding support;
• the second lower support surface abuts against an upper surface of the upper connecting rod located on an outer side of the third hinge axis to prevent a portion of the upper connecting rod located on the outer side of the third hinge axis from upwardly swinging further relative to the second lower support surface during unfolding of the corresponding parallelogram mechanism, thereby preventing further downward swinging of the upper connecting rod to provide unfolding support;
• the second upper support surface abuts against a lower surface of the lower connecting rod located on an inner side of the fourth hinge axis to prevent the inner end of the lower connecting rod from downwardly swinging further during unfolding of the corresponding parallelogram mechanism to provide unfolding support;
• and the second lower support surface abuts against an upper surface of the lower connecting rod located on an outer side of the fourth hinge axis to prevent a portion of the lower connecting rod located on the outer side of the fourth hinge axis from upwardly swinging further relative to the second lower support surface during unfolding of the corresponding parallelogram mechanism, thereby preventing further downward swinging of the lower connecting rod to provide unfolding support.