enter a cambering station and in particular a station according to fr a no 2 549 465 or fr a no 2 604 992 it has for this purpose been heated to a temperature close to 650 u00b0 c which makes it plastic and sensitive to marking by any object coming into contact with it the rotation of rollers 3 gives the glass a speed v1 e g of approximately 20 cm s a beam 4 is positioned above the conveyor parallel to the rollers to beam 4 are fixed e g by slides arms 5 carrying stop means in the form of abutments 6 7 which are fixed in sliding manner on arms 5 the abutments 6 7 are upstream in the direction of the glass sheet movement with respect to the beam 4 and a straight line passing through these abutments corresponds to the desired position of the leading edge of the glass sheet as can be gathered from fig2 the beam 4 is carried at its end by rails 8 8 39 positioned on either side of the conveyor and extending parallel to the axis 2 the rails 8 8 39 run on rollers 9 9 39 and 10 10 39 and are driven in translation by means of carriages 11 11 39 the carriage 11 39 is displaced by a threaded shaft 12 extending parallel to rails 8 rotated by means of a belt 13 actuated by a motor placed beneath the conveyor.