Modular rack storage system and its method of assembly

A modular storage system comprising

• an elongated base part having two spaced continuous channels extending generally parallel to one another longitudinally of said base part, said base part including a longitudinal rim extending along each channel and projecting over a portion of the width thereof, the rims of the two channels projecting in opposite directions towards one another,
• an upright member extendable transversely of said base part, said upright member having a lower edge and including a pair of spaced, downwardly projecting lug means at said lower edge respectively engaged in said channels in said base part, said pair of lug means facing in opposite directions away from one another and being spaced apart in relation to the spacing of said channels so as to be fitted with interference in said channels beneath said rims with the upright member extending in a vertical plane disposed transversely of the base part,
• said lug means being freely insertable into and removable from said channels, without interference from said rims, when the upright member extends in a vertical plane which is angularly offset around a vertical axis from the vertical plane extending transversely of the longitudinal channels, said lug means having engaging surfaces when operatively engaged in said channels with interference fit when the vertical plane containing the upright member extends transversely of the longitudinal channels to elastically and tightly hold said upright member transversely of said longitudinal channels,
• a back member
• two side members,
• said back member having upper and lower edges extending longitudinally of said base part, said side members having front and rear edges, said upright member having front and rear edges, and
• means extending longitudinally along said upper and lower edges of the back member and the rear edges of said upright and side members for resiliently securing the same together in snap-engagement to lock said side members and said upright member to said back member as a rigid assembly on said base part, said means including respective lips and recesses which cooperate so that the lips on one member can engage in the recesses of another member with snap-fit, the parts with the lips including resilient portions on which said lips are formed to provide snap action for engaging lips in the respective recesses,
• the snap engagement of said upright member and said back member acting in combination with the interference fit of the lug means in said channels to resiliently secure the upright member on said rigid assembly on said base part at any selected location along the length of said base part.