NOVELTY - The solar panel rack (100) comprises: multiple hollow sheet metal beams (115) arranged side by side and in parallel with each other to define a plane; a transverse support (110) comprising multiple notches located in its upper edge; and multiple first sheet metal brackets, each of which includes an outer cross-sectional shape conforming to an inner cross-sectional shape of the corresponding notch in the transverse support and an inner cross-sectional shape conforming to an outer-cross sectional shape of the corresponding hollow beam, and is positioned in the corresponding notch.    USE - Used as a solar panel rack.    ADVANTAGE - The cost-effective solar panel rack has reduced weight, desired stiffness and strength, and increased ease and speed of installation.    DETAILED DESCRIPTION - The solar panel rack (100) comprises: multiple hollow sheet metal beams (115) arranged side by side and in parallel with each other to define a plane; a transverse support (110) comprising multiple notches located in its upper edge; multiple first sheet metal brackets, each of which includes an outer cross-sectional shape conforming to an inner cross-sectional shape of the corresponding notch in the transverse support and an inner cross-sectional shape conforming to an outer-cross sectional shape of the corresponding hollow sheet metal beam, is positioned in the corresponding notch in the transverse support and attached to and supports the corresponding hollow sheet metal beam within the corresponding notch in the transverse support; and multiple second sheet metal brackets, each of which includes an inner cross-sectional shape conforming to the outer cross-sectional shape of the corresponding hollow sheet metal beam, and is positioned on and attached to the corresponding hollow sheet metal beam, and configured to couple to a solar panel (130) or solar panel assembly to position and attach the solar panel or solar panel assembly to the solar panel rack in a desired location in the plane defined by the hollow sheet metal beams. Each hollow sheet metal beam is formed by bending a sheet metal blank along bend lines predefined in the sheet metal blank by bend-inducing features. Each of the bend-inducing features has a length (A) and a radius of curvature (R) at each end, where R is approximately a minimum radius of curvature required to prevent cracking at ends of the bend-inducing features upon bending of the blank along the bend lines, and A is greater than or equal to 2R. Each hollow sheet metal beam is formed by bending the sheet metal blank comprising preformed tabs and slots configured to secure the sheet metal blank in its beam configuration upon bending of the blank into the beam configuration and formed by bending the sheet metal blank comprising preformed slots or other openings configured to predefine the locations at which the solar panels or solar panel assemblies are attached to the solar panel rack. The transverse support is formed by bending the sheet metal blank along the bend lines predefined in the sheet metal blank by the bend-inducing features. The transverse support comprises flanges forming side walls for the notches, where the side walls of each notch are attached to opposite sides of the first sheet metal bracket positioned in the notch. The transverse support is formed by bending the sheet metal blank comprising the preformed tabs or slots configured to engage the corresponding slots or tabs in the first sheet metal bracket to partially secure the first sheet metal bracket in a position on the transverse support. Each first sheet metal bracket is formed by bending the sheet metal blank along the bend lines predefined in the sheet metal blank by the bend-inducing features and by bending the sheet metal blank comprising the preformed tabs or slots configured to engage the corresponding slots or tabs in the transverse support to partially secure the first sheet metal bracket in position on the transverse support. Each first sheet metal bracket extends beyond the transverse support in both directions along its corresponding hollow sheet metal beam and is progressively less stiff with increasing distance from the transverse support. Each first sheet metal bracket comprises upper flanges configured to be closed around the hollow sheet metal beam to capture the hollow sheet metal beam within the first sheet metal bracket. Each second sheet metal bracket is formed by bending the sheet metal blank along the bend lines predefined in the sheet metal blank by the bend-inducing features, and comprises upwardly pointing tabs configured to contact features on the solar panels or solar panel assemblies to position the solar panel or solar panel assembly in a desired location and configured to be clinched to features on the solar panels or solar panel assemblies to attach the solar panel or solar panel assembly to the solar panel rack. A pair of two clinching tabs is simultaneously clinched to attach the solar panels or solar panel assemblies to the solar panel rack. The solar panel rack further comprises: a hollow sheet metal beam arranged collinearly with one of the side-by-side hollow sheet metal beams; and an expandable and collapsible sheet metal splice configured to be bent along the predefined bend lines to assume a collapsed configuration, inserted, while in the collapsed configuration, into adjoining ends of the collinear hollow sheet metal beams, expanded to a configuration having an outer cross-sectional shape conforming to and tightly fitting an internal cross-sectional shape of the collinear hollow sheet metal beams, and then attached to both of the collinear hollow sheet metal beams to couple the collinear hollow sheet metal beams to each other. The expandable and collapsible sheet metal splice is formed by bending the sheet metal blank along the bend lines predefined in the sheet metal blank by the bend-inducing features. Each sheet metal bracket comprises upwardly pointing positioning tabs configured to contact features on the solar panels or solar panel assemblies to position the solar panels or solar panel assemblies in the desired location. The positioning tabs of each sheet metal bracket are located in a square or rectangular arrangement in a central portion of a top panel of the sheet metal bracket and extend upward from the top panel. Each sheet metal bracket is configured to position and attach adjacent corners of the solar panels or solar panel assemblies to the solar panel rack. Each sheet metal bracket has the inner cross-sectional shape conforming to an outer cross-sectional shape of the hollow sheet metal beam to which it is attached.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a portion of a solar panel rack with solar panels mounted on the rack.    Solar panel rack (100)    Vertical support (105)    Transverse support (110)    Hollow sheet metal beams (115)    Solar panel. (130)