locking system with a catch or a locking cam on one side of the box and a hinge onthe other in that case the box will be engaged in the molding cell obliquely keyed in the hinge and then pivoted to be set in place and locked in position by means of the catch of the locking cam such systems make it possible to replace the premolding system very rapidlywith a total interruption of the installation of only 15 minutes replacement of the upper mold alone is also possible for that purpose themold is advantageously mounted by stays 37 on a support rod 38 as represented in fig7 a 7b the support rod 38 is engaged in a centering hole 39 bored in the vacuum box and maintained at its other end by an eccentric 40 to position the plate correctly lugs 41 are used but such a system can be replaced by a two support rod system with centering finger and locking cam or even with guide and locking catch with such a system the upper mold alone can be replaced in only five minutes the replacement times indicated are to be understood as 34 good volume to good volume 34 that is they include the loading time and are to be compared with those of facilities containing refractory mortar molds and for which the production interruptions are never less than one hour the tests were conducted in a facility such as previously described the working temperatures are on the order of 700 u00b0 c in the furnace and 680 u00b0 c in the molding cell the temperature of the glass immediately before its suction and after its deposition on the lower.