Integrated self-opening and self-closing stairs-climbing trolley case

An integrated self-opening and self-closing stairs-climbing trolley case, comprising a case body, universal wheels, a telescopic draw bar, a sliding plate, unidirectional wheels, an elastic device, a shock-absorbing device, limiting connecting rods, torsional spring connecting rods, an inner bracket, a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod, wherein

• a bottom of the case body is provided with the universal wheels,
• a bottom of the sliding plate is provided with the unidirectional wheels,
• the telescopic draw bar is arranged on a side of the case body,
• the inner bracket is respectively connected with the telescopic draw bar and the case body, the limiting connecting rods on left and right sides are movably connected with the inner bracket via the first connecting rod and the limiting connecting rods are movably connected with the sliding plate via the second connecting rod,
• the torsional spring connecting rods on the left and right sides are movably connected with the inner bracket via the third connecting rod and the torsional spring connecting rods are movably connected with the sliding plate via the fourth connecting rod,
• the limiting connecting rods, the inner bracket, the torsional spring connecting rods and the sliding plate form a double rocker bar mechanism,
• a first end of the elastic device is connected with the inner bracket and a second end of the elastic device is connected with the fourth connecting rod,
• the shock-absorbing device is arranged between the sliding plate and the inner bracket,
• the sliding plate drives the unidirectional wheels to displace upwards via elastic forces of the elastic device and the shock-absorbing device until tops of the limiting connecting rods abut against the inner bracket, wherein when the sliding plate is in a normally closed state with respect to the case body, a bottom horizontal line of each of the unidirectional wheels is higher than a bottom horizontal line of each of the universal wheels;
• and
• when the sliding plate is subjected to an external force, the sliding plate drives the unidirectional wheels to displace downwards until bottoms of the torsional spring connecting rods abut against the inner bracket, wherein when the sliding plate is in an open state with respect to the case body, the bottom horizontal line of each of the unidirectional wheels is lower than the bottom horizontal line of each of the universal wheels.