VACUUM DRUM FOR LABELLER TO WHICH PORT IS FORMED GRADUALLY

摘要

A vacuum drum for carrying a label held to its surface by vacuum past an adhesive applying roll to a position where the label will touch a container and the container will be rolled along the drum surface to thereby apply the label about the container. The drum is provided with a circumferential series of vacuum ports that extend through its outer surface. The vacuum to the ports is fed through passages in a bottom support plate for the drum and the passages all communicate with a stationary vacuum chamber in a collector ring which is held against the inner surface of the drum supporting plate. The collector ring vacuum chamber extends about the axis of the ring for about 180 DEG and at one end thereof serves to close off the passages to the drum in radial succession as the label is transferred to the container. Each passage, after being shut off from the vacuum, is vented. The passages which connect to the label leading edge vacuum ports are connected to an air pressure chamber in the collector ring immediately after being cut off from vacuum to assist in the transfer of the leading edge of the label to the container.