Automatic stacker

Claim 2

An automatic stacking machine for stackable articles which have a generally horizontal margin at each of opposite sides, said machine comprising an inverted U-shaped structure the legs of which straddle a conveyor means for delivering an article to be stacked to a fixed location between said legs, means on said machine for positioning a conveyor delivered article at said location, article lifting means projecting toward said location from each of said legs at a level to engage an article below its margin at said location, article holding means projecting from said legs in the direction of said lifting means and at a stacking position above and vertically aligned with said lifting means, means for operating said lifting means to engage the margin of and raise an article to above the level of said holding means, means to retract said holding means to pass said article and said lifting means and to then return the holding means to its initial projected position, and means for retracting said lifting means at the stacking position to deposit a lifted article onto said holding means and to then return the retracted lifting means to a level below and outwardly of the margin of an article at said fixed location and at that level return the lifting means to its initial position.

Claim 3

The stacking machine defined by claim 1 wherein the operation of the holding means is in timed relation with the operation of the lifting means whereby a stackable article is raised to stacking position while the holding means is being retracted to pass the article and the lifting means, the holding means is then returned to its initial position while the lifting means is retracted to deposit the article onto the holding means, and the retracted lifting means is then lowered to the level of the said location and thereafter returned to its initial position at said location in one uninterrupted cycle of lifting means operation.

Claim 4

The stacking machine according to claim 2 wherein the operation cycle of the lifting means is initiated solely by the positioning of an article at said location.

Claim 5

An automatic stacker for stackable items having a generally horizontal margin extending from each of its opposite sides, a conveyor means for transporting the stackable items toward the stacker in randomly spaced relation with each other, the stacker being an inverted U-shaped structure positioned above the conveyor and having its legs straddling the conveyor, means for receiving a stackable item at fixed location between the stacker legs, item lifting means on each of said stacker legs positioned to extend beneath the margins of said item at a first position and operable to lift the item to an elevated position above the conveyor and to then return to its first position, item holding means at a predetermined level below said elevated position and in the raising path of the lifted item, said holding means being adapted to receive and to hold the lifted item, means for retracting the holding means as the lifting means approaches the level of the holding means to allow the lifted item to pass to said elevated position and then projecting the holding means to its initial item holding position, and means for retracting the lifting means from engagement with the item margin upon return of the holding means to its initial position, the lifting means remaining retracted until near its first position and then moving inwardly to underlie the margin of an incoming item to be stacked.

Claim 6

An automatic stacker for stackable items having a generally horizontal margin extending from each of its opposite sides, a conveyor means for transporting the stackable items toward the stacker in randomly spaced relation with each other, the stacker being an inverted U-shaped structure positioned above the conveyor and having its legs straddling the conveyor, means for receiving a stackable item at fixed location between the stacker legs, item lifting means on each of said stacker legs positioned to extend beneath the margins of said item at a first position and operable to lift the item to an elevated position above the conveyor and to then return to its first position, item holding means at a predetermined level below said elevated position and in the raising path of the lifted item, said holding means being adapted to receive and to hold the lifted item, means for retracting the holding means as the lifting means approaches the level of the holding means to allow the lifted item to pass to said elevated position and then projecting the holding means to its initial item holding position, and means for retracting the lifting means from engagement with the item margin upon return of the holding means to its initial position, the lifting means remaining retracted until near its first position and then moving inwardly to underlie the margin of an incoming item to be stacked.

Claim 7

A stacking machine according to claim 4 wherein an electrically actuated counting means is provided to individually register the stackable items deposited on said holding means, said counting means being adapted to produce an electrical signal when a predetermined number of said items has been deposited on the holding means, a downwardly extending slide mounted on said stacker structure adjacent the level of said holding means and extending forwardly therefrom, pusher means on said structure mounted rearwardly of items deposited and stacked on said holding means and adapted to engage the stacked items with a forwardly pushing motion, means for operating said pusher means with a forward and then rearward motion to push stacked items from the holding means and onto said slide, and means actuated by a signal from said counting means for actuating the pusher operating means.