26 and curved panel 28 to improve the rigidity of the bucket 20 as well as to lessen friction and wear of the bottom panel 26 disposed transversely across the top of the bucket 20 generally in the plane of the top panel 24 are a front beam 40a and a rear beam 40b the beams 40a and 40b are preferably circular in cross section but may of course define other cross sections compatible with the demountable interconnection 10 the top panel 24 defines a pair of opposed non parallel inner edges 42 the beams 40a and 40b and the inner edges 42 of the top panel 24 define a generally trapezoidal opening 44 which tapers toward the front of the bucket 20 the function and advantages of the trapezoidal opening 44 will be described in greater detail in the section dealing with the operation of the demountable interconnection 10 freely rotatably disposed on the rear beam 40b is a locking clevis 46 the clevis 46 is generally u shaped and defines at least two aligned openings not illustrated disposed in its leg positions which rotatably mount the clevis 46 clevis includes a pair of obliquelty disposed ears 48 which are oriented upwardly and outwardly when the clevis 46 is in its released position illustrated in fig3 and 4 the locking clevis 46 also includes a pair of stop structures 50 which take the form of outwardly extending tabs on the left and right sides of the locking clevis 46 the stop structures 50 interfere with the curved panel 28.