embodiment such means may comprise a pneumatic cylinder 120 which may be mounted in part exteriorly of the chamber fig2 the pneumatic cylinder in turn is connected to an engagement bar 121 oriented within the chamber to engage the rear portion 115 of cams 113 for removing the separating arms 114 of the cams 113 from their separating positions between the glass panes other mechanical or electro mechanical apparatus may alternatively utilized to accomplish the function of so manipulating the cams a second pneumatic cylinder 125 or equivalent means may similarly be positioned on the vacuum chamber for use in compressing the stack of glass units after the separating arms 114 of the cams 113 have been removed from their separating positions as described in greater detail below referring to fig1 3 a conveyor is shown generally at 50 the conveyor typified in the drawing comprises a series of generally horizontally extending rollers 52 having ends journaled into angle iron supports 54 56 the angle iron supports having a first section extending up to the doorway of the vacuum chamber a second section within the vacuum chamber and a third section shown in fig1 and 3 extending outwardly of the vacuum chamber on the.