those skilled in the art and therefore need not here be further considered beyond any disclosure thereof made herein turning attention now to fig1 and 2 it will be seen that a sun wheel 1 or equivalent structure is securely mounted on a shaft 2 the shaft 2 is supported by an arm 24 secured on the not particularly illustrated machine frame the arm 24 at its end 24a which supports the shaft 2 is constructed as a clamping strap or bracket 50 whose two clamping jaws generally indicated by reference character 51 are held or clamped together by a suitable fixing element here shown as a threaded screw or bolt 25 the manner in which the arm 24 is secured to the machine frame has not been shown since this is not crucial to the invention but purely by way of example may be accomplished in the manner disclosed for instance in the aforementioned u s pat no 3 320 978 to which reference may be readily had and the disclosure of which is incorporated herein by reference a supporting disk 3 is arranged at one side 1a of the sun wheel 1 and is rotatably mounted by bearing means 60 on the shaft 2 a member 4 here shown as a prismatic member is securely connected in any desired manner with such supporting disk 3 this prismatic member 4 likewise is rotatably seated by the bearing means 60 and 61 upon the.