introducing hydraulic fluid to space 48 via fluid line 51 thus drawing piston 49 and rod 44 toward end plate 45 and thereby pulling dipper stick member 34 toward the pivot plates 36 rotation of dipper stick arm 15 as mentioned heretofore is accomplished through hydraulic rotator assembly 35 incorporated into such arm at its pivot end the rotator assembly is principally comprised of an annular housing 52 cylindrical rotator element 53 positioned internally of the housing and rotator housing end plates 54a and 54b the housing 52 and rotator element 53 together form an annular space 55 housing 52 bears an internal hydraulic fluid dam 56 which extends radially throughout the length of space 55 toward and to the rotator element the cylindrical rotator element 53 bears a wing portion 57 which extends radially throughout the length of space 55 toward and to the inner wall 58 of housing 52 by particular reference to fig4 it will be seen that rotator element 53 shown in its normal position may rotate within housing 52 over approximately 150 u00b0 clockwise and 150 u00b0 counterclockwise from such normal position the rotatable position of rotator element 53 within housing 52 is established by introducing and withdrawing hydraulic fluid from space 55 on either side of wing portion 57 forming with fluid dam 56 sub spaces 55a and 55b thus hydraulic fluid may be introduced to sub space 55a through a fluid line 59 and withdrawn from sub space 55b through a fluid line 60 to move and position wing portion 57 clockwise of its normally vertical position by introducing hydraulic fluid through line 60 to sub space 55b while.