1. A detachable inner sliding rail mounting structure for use in a server sliding rail assembly that has an inner sliding rail and another sliding rail that includes a stop block, the detachable inner sliding rail mounting structure connected to the inner sliding rail and comprising:a pull bar, a plastic pull tab, a guide block and an engagement plate, wherein:
said pull bar is slidably mounted along an inner bottom surface of said inner sliding rail and comprises a connection hole located at a rear end thereof, a connection member having a shank connected to said connection hole to pivotally connect said engagement plate to said pull bar, an elongated slot that receives a positioning member of said inner sliding rail that limits the range of forward-rearward sliding movement of said pull bar relative to said inner sliding rail, and an opposing front end connected to said plastic pull tab;
said plastic pull tab comprises a sliding groove, two rails respectively extended along two opposite lateral sides of said sliding groove and being coupled to said guide block so that said plastic pull tab is movable forward and rearward relative to said guide block, a spring retaining portion located at a rear side relative to said sliding groove, and a spring having one end thereof connected to said spring retaining portion and an opposite end thereof connected to said guide block such that at rest said pull tab is in a rearward position and when said plastic pull tab is being pulled forward, said spring is compressed, and when said pulling force is removed, an elastic restoring energy of said spring moves said plastic pull tab to the rearward position;
said guide block comprises two guide grooves arranged at two opposite lateral sides thereof and that are respectively coupled to said two rails of said plastic pull tab, a mounting portion located at a bottom side thereof and connected to a positioning groove of said inner sliding rail, and a spring retainer tip located at a rear end thereof and connected to said opposite end of said spring;
said engagement plate comprises a first pivot hole located near a rear end thereof and being pivotally connected to a second pivot hole at said inner bottom surface of said inner sliding rail via a pivot pin, a front guide edge, a rear guide edge, a retaining notch disposed between said front guide edge and said rear guide edge and detachably engageable with said stop block of said another sliding rail, a first guide slot that receives said shank of said connection member of said pull bar so that said shank of said connection member of said pull bar is movable along said first guide slot to move said engagement plate and to further force said retaining notch of said engagement plate away from said stop block of said another sliding rail, and a second guide slot for enabling a front part of said engagement plate to be directly driven to move said engagement plate in a direction disengaging said retaining notch from said stop block of said another sliding rail, said rear end of said engagement plate being abutted against an elastic arm of an elastic member at said inner sliding rail so that when said front part of said engagement plate is moved away from its rest position so as to disengage said retaining notch from said stop block of said another sliding rail, said rear end of said engagement plate is forced to compress said elastic arm, and when the force to compress the elastic arm is removed from said engagement plate, an elastic restoring energy of said elastic arm biases said engagement plate to return to its rest position.