Preform-Heating Furnace Comprising a Member for Controlling the Movement of a Heating Means Between Indexed Positions

A furnace (10) for heating preforms (20), particularly preforms made of thermoplastic designed for the manufacture of receptacles by blow molding or by stretch-blow molding, of the type comprising at least one longitudinal tunnel (12) for heating at least a part (22, 24) of the preforms (20), the tunnel comprising at least one heating module (18) with vertical walls (14, 16) between which the preforms (20) travel, at least one vertical wall of the heating module (18) being provided with at least one radiation heating means (32) that is mounted so as to be movable transversely on supports (34) and means (40) for adjusting the transverse position of the heating means (32) to adjust the transverse distance between the heating means (32) and said part (22, 24) of the preforms (20), the means (40) for adjusting the position of the heating means (32) comprising at least one member (42) for controlling the movement of the heating means (32) between at least two, respectively proximal and distal, transverse positions that are indexed by indexation means (54, 56, 58) intervening between the control member (42) and the supports (34) so as to position the heating means (32) at a determined transverse distance from said part (22, 24) of the preforms (20), characterized in that the control member (42) comprises an indexation boss (54) that is able to deform elastically so as to fit into complementary indexation notches (56, 58) of the support (34) corresponding respectively to the proximal and distal positions.