A rack assembly has two support frames and at least one shelf that are secured to the support frames by connecting assemblies. Each connecting assembly comprises a well secured to a medial surface of each vertical tube of the support frame, and a hook that extends from each end of each shelf, with each hook having an opening extending therethrough. The connecting assembly also includes a connector that is seated inside each well, each connector having a top plate that has an elongated opening, the connector also having a body that is sized and configured to fit inside a well, the body defining two wings with a space between the wings, and wherein each wing has a bump positioned in the center of the inner surface of each wing that faces the space. Each hook is inserted through the elongated opening of a corresponding connector with the bump on each wing fitted inside the opening of the hook to retain the hook inside the body of the connector.