Shelf and ladder combination

A shelf and ladder combination comprising:

• a shelf unit including
• a frame including two support rod units each of which extends in a first direction, and a plurality of partition plates each of which extends in a second direction transverse to the first direction, said support rod units being spaced apart from each other in the second direction, each of said support rod units having a top end portion and a bottom end portion opposite to each other in the first direction, said partition plates being connected between said support rod units and being spaced apart from each other in the first direction, and
• a positioning unit including a crossbar that extends in the second direction, that is spaced apart from said frame in a third direction transverse to the first and second directions and that is proximate to said top end portions of said support rod units, and two main connecting brackets each of which is connected between said crossbar and said top end portion of a corresponding one of said support rod units;
• and
• a ladder unit including two ladder legs extending in the first direction and spaced apart from each other in the second direction, at least one fixing unit that is connected to one of said ladder legs, that is sleeved on said crossbar and that is slidable along said crossbar in the second direction, and a plurality of rungs connected between said ladder legs and spaced apart from each other in the first direction, each of said ladder legs having a first end portion adjacent to said crossbar, and a second end portion opposite to said first end portion in the first direction;
• wherein said at least one fixing unit is connected to said first end portion of one of said ladder legs;
• wherein said frame further includes at least one reinforcement unit that extends in the first direction, that is disposed between said support rod units and that is connected to said partition plates, said at least one reinforcement unit having a connection end portion and a support end portion opposite to each other in the first direction, said crossbar being proximate to said connection end portion, said positioning unit further including at least one auxiliary connecting bracket connected between said crossbar and said at least one reinforcement unit, said at least one auxiliary connecting bracket having an auxiliary extension arm extending downwardly from said crossbar in the first direction toward said support end portion, an auxiliary bight portion extending from one end of said auxiliary extension arm, which is opposite to said crossbar, in the third direction toward said at least one reinforcement unit, and an auxiliary fixed arm connected between one end of said bight portion, which is opposite to said auxiliary extension arm, and said at least one reinforcement unit;
• wherein said at least one fixing unit includes a base member having a main portion connected to said first end portion of said one of said ladder legs, a connecting portion extending from one end of said main portion and partially surrounding said crossbar, and an extension portion extending transversely from the other end of said main portion in a direction away from said first end portion of said one of said ladder legs and opposite to said connecting portion, wherein said main portion, said connecting portion and said extension portion cooperatively define an insertion space for insertion of said crossbar therethrough, said insertion space having an opening located between a bottom edge of said connecting portion and an outer edge of said extension portion which is distal to said main portion, said opening permitting passage of a corresponding one of each of said main connecting brackets and said at least one auxiliary connecting bracket therethrough;
• and
• wherein said at least one fixing unit further includes a switchable member having a pivot end portion pivotally connected to said connecting portion, and a free end portion opposite to said pivot end portion, said switchable member being rotatable relative to said base member between a closed position, in which said switchable member closes said opening and said free end portion is immediately adjacent to said extension portion, and an open position, in which said free end portion is distal to said extension portion such that said opening is opened.