Assembly apparatus

An assembly apparatus comprising:

• a spline sleeve defining a central hole having an inner surface, the inner surface defining a plurality of first sliding grooves and a plurality of second sliding grooves, wherein the first and second sliding grooves extend axially and are alternately and evenly distributed along the circumference of the spline sleeve, and the number of first sliding grooves is equal to the number of second sliding grooves;
• a first connecting member and a second connecting member positioned on opposite ends of the spline sleeve;
• a sliding member sildably received in the spline sleeve and comprising at least one first key portion slidably engaged in a corresponding first sliding groove;
• a rotation member rotatable relative to the sliding member and comprising a plurality of second key portions selectively slidably engaged in the corresponding first sliding grooves and interfering with corresponding second sliding grooves;
• a first elastic member positioned between and abutting the first connecting member and the rotation member;
• a second elastic member positioned between and abutting the second connecting member and the sliding member;
• and
• a knockout pin assembly fixed to the sliding member and slidable relative to the second connecting member;
• wherein the rotation member forms a plurality of first teeth on an end surface, and the sliding member forms a plurality of second teeth engaging with the first teeth, when the second key portions slide out of the corresponding first sliding groove, a phase difference exists between the first teeth and the second teeth, such that the rotation member tends to rotate relative to the sliding member to interfere with the corresponding second sliding grooves, and the number of first teeth and second teeth is twice the number of the first and second sliding grooves.