Type of cushion adjustment mechanism and the child tricycle

A cushion adjustment mechanism, comprising:

• a cushion;
• a main beam tube;
• wherein one end of the main beam tube is connected with the cushion, and another end of the main beam tube is connected with a tricycle body;
• an adjustment unit, fixedly connected with the main beam tube, and is provided with a positioning assembly;
• a rear part, which comprises two fixing plates located on two sides of the adjustment unit respectively;
• each of the two fixing plate is provided with a rotation hole;
• one end of each of the two fixing plates is connected with a rear wheel, and another end of each of the two fixing plates is connected with the adjustment unit;
• said another end of each of the fixing plates connected with the adjustment unit is provided with a counter locking screw rod;
• one end of the counter locking screw rod passes through the rotation hole and is fixedly connected with the adjustment unit, and another end of the counter locking screw rod is connected with a respective fixing plate rotatable around the counter locking screw rod;
• one side of each of the two fixing plates facing towards the adjustment unit is provided with at least two positioning grooves vertically spaced apart from one another:
• the positioning assembly includes a positioning part inserted into corresponding positioning grooves of the two fixing plates wherein said corresponding positioning grooves face each other at a same height;
• the adjustment unit also comprises a control unit;
• a bottom of the adjustment unit is provided with a guide groove, the control unit passes through the guide groove, and the control unit is slidable in the guide groove;
• the control unit includes a slide block and a first resetting spring, one end of the first resetting spring presses against an inner wall of the adjustment unit, and another end of the first resetting spring presses against the slide block;
• the slide block is fitted in the guide groove;
• an upper end of the slide block is connected with the positioning part, and a lower end of the slide block passes through the guide groove;
• the slide block is slidable in the guide groove.