27a of more slender cross section and serves as a stop for the pulley 1 the locking segment 27a rests on the end remote from the intermediate segment 4 of each leg 19a the pulley 1 has two fastening bracket receptacles 37 corresponding to the spacing of the locking segments 27a their cross section corresponds to the cross section of the locking segments 27a so that the pulley 1 is seated without circumferential play on the fastening bracket 2a upon installation the pulley 1 is slipped onto the two legs 19a of the fastening bracket 2a far enough that the pulley 1 rests on the shoulders 21 of the fastening bracket 2a that are formed by the locking segments 27a and the spacer segments 26 the locking segments 27a of the fastening bracket 2a penetrate the fastening bracket receptacles 37 of the pulley 1 at least far enough that part of each locking segment 27a protrudes in the form of a bent over tab 41 past the pulley 1 for fixing the pulley 1 on the fastening bracket 2a the bent over tab 41 of each leg 19a of the fastening bracket 2a protruding past the pulley 1 on the side remote from the throttle valve shaft 3 is bent over counter to the course of each leg 19a in the fastening receptacles 37 so that a form fitting connection is established between the pulley and the fastening bracket 2a and the pulley 1 is firmly joined to the fastening bracket 2a in fig5 the bent over tab 41 is shown in dashed lines in a position not bent at an angle for installation and.