Abstract: A detented safety coupling assembly for use with an indexing apparatus for advancing a workpiece through a series of workstations is disclosed. The indexing apparatus may include a plurality of workstations arranged in spaced relationship, at least one pallet which supports the workpiece as it passes through the workstations and a drive assembly for moving the pallet through the workstations. The safety coupling assembly releasably couples the drive assembly and the pallet such that movement of the drive assembly causes corresponding movement of the pallet when the forces acting on the coupling assembly do not exceed a predetermined value. The coupling assembly ceases to couple the drive assembly and the pallet, without breakage, when the forces acting on the coupling assembly exceed a predetermined value.

Abstract: A conveying system for a multicolor screen printer line having a work station for each color has a plurality of work platens which are moved successively through the work stations. Vacuum plenums are provided for holding the work in position on the platens both in the stationary position in the work stations and while the platens are moving and being indexed between stations. This is accomplished by having two sets of vacuum connectors for the platens with these two sets applying the vacuum at different times in the cycle. In one embodiment, there are fixed vacuum connectors at each work station and movable vacuum connectors that reciprocate back-and-forth between work stations. In a second embodiment, there are two sets of movable vacuum connectors with the two sets moving simultaneously in opposite directions.