A locking apparatus for a pet cage, comprising: a turntable rotatable about a central axis of rotation; at least one elongate metal lock bar, said elongate metal lock bar configured to extend along a radial line originating from the axis of rotation of the turntable; a connecting member for operably connecting the elongate metal lock bar and the turntable; the connecting member comprising: a forwardly extending portion for receiving a front section of the elongate metal lock bar and fixing a retained end of the elongate metal lock bar to the connecting member; wherein the forwardly extending portion of the connecting member comprises a first channel for receiving the elongate metal lock bar, the first channel located on a lower side of the forwardly extending portion, and wherein the first channel comprises limit ribs located on side walls of the first channel, the limit ribs configured for limiting the up-and-down movement of the elongate metal lock bar, and wherein the forwardly extending portion further includes a through hole located on an inner end of the forwardly extending portion, the through hole configured to receive and fix the retained end of the elongate metal lock bar that has been bent at 90 degrees with respect to the remaining elongate metal lock bar, and wherein the shape of the first channel and the through hole matches with that of the elongate metal lock bar after being bent at 90 degrees; and a rearward extending portion which extends parallel with and is outwardly offset from the forwardly extending portion; and a linear conversion mechanism arranged between the turntable and the rearward extending portion of the connecting member; the linear conversion mechanism configured to convert rotation of the turntable about the axis of rotation to linear movement of the connecting member in the same direction as a longitudinal direction of the elongate metal lock bar. a turntable rotatable about a central axis of rotation; at least one elongate metal lock bar, said elongate metal lock bar configured to extend along a radial line originating from the axis of rotation of the turntable; a connecting member for operably connecting the elongate metal lock bar and the turntable; the connecting member comprising: a forwardly extending portion for receiving a front section of the elongate metal lock bar and fixing a retained end of the elongate metal lock bar to the connecting member; wherein the forwardly extending portion of the connecting member comprises a first channel for receiving the elongate metal lock bar, the first channel located on a lower side of the forwardly extending portion, and wherein the first channel comprises limit ribs located on side walls of the first channel, the limit ribs configured for limiting the up-and-down movement of the elongate metal lock bar, and wherein the forwardly extending portion further includes a through hole located on an inner end of the forwardly extending portion, the through hole configured to receive and fix the retained end of the elongate metal lock bar that has been bent at 90 degrees with respect to the remaining elongate metal lock bar, and wherein the shape of the first channel and the through hole matches with that of the elongate metal lock bar after being bent at 90 degrees; and a rearward extending portion which extends parallel with and is outwardly offset from the forwardly extending portion; and a linear conversion mechanism arranged between the turntable and the rearward extending portion of the connecting member; the linear conversion mechanism configured to convert rotation of the turntable about the axis of rotation to linear movement of the connecting member in the same direction as a longitudinal direction of the elongate metal lock bar. a forwardly extending portion for receiving a front section of the elongate metal lock bar and fixing a retained end of the elongate metal lock bar to the connecting member; wherein the forwardly extending portion of the connecting member comprises a first channel for receiving the elongate metal lock bar, the first channel located on a lower side of the forwardly extending portion, and wherein the first channel comprises limit ribs located on side walls of the first channel, the limit ribs configured for limiting the up-and-down movement of the elongate metal lock bar, and wherein the forwardly extending portion further includes a through hole located on an inner end of the forwardly extending portion, the through hole configured to receive and fix the retained end of the elongate metal lock bar that has been bent at 90 degrees with respect to the remaining elongate metal lock bar, and wherein the shape of the first channel and the through hole matches with that of the elongate metal lock bar after being bent at 90 degrees; and a rearward extending portion which extends parallel with and is outwardly offset from the forwardly extending portion; and a linear conversion mechanism arranged between the turntable and the rearward extending portion of the connecting member; the linear conversion mechanism configured to convert rotation of the turntable about the axis of rotation to linear movement of the connecting member in the same direction as a longitudinal direction of the elongate metal lock bar.