A coupling assembly, comprising: two screw rods arranged in parallel; a holder mounted on the two screw rods ; two shaft sleeve sets; and two connection rod sets, each of which is coupled to a corresponding one of the two shaft sleeve sets, characterized in that each of the two shaft sleeve sets comprises: a first shaft sleeve embedded in the holder , the holder restricting movement of the first shaft sleeve in an extension direction of the screw rod , and at least part of the screw rod being arranged in the first shaft sleeve , and a second shaft sleeve fitted over the screw rod at an outer side and movable on the screw rod ; and each of the two connection rod sets comprises: a first connection rod having a first end fixedly coupled to the first shaft sleeve , and a second connection rod having a first end fixedly coupled to the second shaft sleeve , the second connection rod and the first connection rod crossing with each other and being coupled at a junction; wherein there is a first distance between the first shaft sleeve and the second shaft sleeve , and the first connection rod and the second connection rod cross to form a first angle; there is a second distance between the first shaft sleeve and the second shaft sleeve , and the first connection rod and the second connection rod cross to form a second angle; the second angle is different from the first angle. two screw rods arranged in parallel; a holder mounted on the two screw rods ; two shaft sleeve sets; and two connection rod sets, each of which is coupled to a corresponding one of the two shaft sleeve sets, characterized in that each of the two shaft sleeve sets comprises: a first shaft sleeve embedded in the holder , the holder restricting movement of the first shaft sleeve in an extension direction of the screw rod , and at least part of the screw rod being arranged in the first shaft sleeve , and a second shaft sleeve fitted over the screw rod at an outer side and movable on the screw rod ; and a first shaft sleeve embedded in the holder , the holder restricting movement of the first shaft sleeve in an extension direction of the screw rod , and at least part of the screw rod being arranged in the first shaft sleeve , and a second shaft sleeve fitted over the screw rod at an outer side and movable on the screw rod ; and each of the two connection rod sets comprises: a first connection rod having a first end fixedly coupled to the first shaft sleeve , and a second connection rod having a first end fixedly coupled to the second shaft sleeve , the second connection rod and the first connection rod crossing with each other and being coupled at a junction; a first connection rod having a first end fixedly coupled to the first shaft sleeve , and a second connection rod having a first end fixedly coupled to the second shaft sleeve , the second connection rod and the first connection rod crossing with each other and being coupled at a junction; wherein there is a first distance between the first shaft sleeve and the second shaft sleeve , and the first connection rod and the second connection rod cross to form a first angle; there is a second distance between the first shaft sleeve and the second shaft sleeve , and the first connection rod and the second connection rod cross to form a second angle; the second angle is different from the first angle. <EOS>