This invention relates to the handling of articles and, more particularly, it has for its object a method and apparatus for sequentially forming numbered stacks of regular articles, such as cigarette packs and the like.
Stack forming devices for cigarette packs have already been proposed, in which a pusher plunger engages and pushes one after the other the packs fed in a row along a track, until a stack of a preset number of packs is formed; this stack is then transferred to a delivery channel by a transferring plunger, which operates every time that a preset number of pusher plunger strokes has been effected.
In these known devices there is the inconvenience that, due to feed failures or the like, the transferred stacks are not always complete. This involves the necessity of checking the stacks in height after the transfer, and to provide means to deviate the incomplete stacks for rejection. On the other hand, since the delivery end of the stacker feeds other stack handling devices, it is convenient that the feed from this delivery end be absolutely regular, since the rejections of the incomplete stacks cause a feed discontinuity which disturbs the operation of these latter devices.
There arises, therefore, the problem of obtaining a stacking system which allows to always provide at the stacker delivery end absolutely regular stacks, with the absolute certainty that there will be no incomplete stacks to be rejected.
This invention is aimed at solving this problem and, for this purpose, it proposes a method for forming stacks of numbered packs or the like, according to which a stack of a number n of packs is formed in a stacking station, by stacking n-1 packs from the channel of arrival which feeds the stacking plunger, and by completing the stack with a pack, supplied from a magazine which is positioned above the stacking station, the control for the transfer of such a stack being caused to depend on the double check of the magazine and of the stack formed by the stacking plunger, so as to obtain in each case the certainty of the regularity of the stack to be transferred.
Consequently the invention proposes a stacker of packs or the like, using the above method, and comprising a frame for a vertical stacking station, surmounted by a magazine, with a reciprocating pusher for stacking from the bottom the packs from a channel which conveys them to the bottom of the station, and with a plunger transferring the predetermined stack from the station to an outlet of the same station, the stacking pusher and the transferring plunger being both operated by a common drive shaft through reduction gears or chain drives and reciprocating cam drives, the action of the transferring plunger being subordinated to the consent of photoelectric cell checking means which sense the filling condition of the magazine and the partial completion condition of the stack being formed.
These and other features of the invention and the resulting advantages, will be apparent from the following description of a preferred embodiment made with reference to the attached drawings.