Apparatus for transferring trays between a conveyor system and a stack

Claim 3

An apparatus according to claim 1 including means operative in response to advance of a tray along said overhead conveyor means to a position above said elevator means for operating said transfer means to move a tray from the overhead conveyor means to a stack on said elevator means.

Claim 4

An apparatus according to claim 1 including stop means mounted for movement between an operative position in the path of movement of trays along said overhead conveyor means and an inoperative position out of the path of movement of said trays, said stop means in said operative position thereof being arranged to stop trays on said overhead conveyor means above said elevator means.

Claim 5

An apparatus according to claim 3 including means operative when a tray engages said stop means for operating said transfer means to move a tray from the overhead conveyor means to a stack on said elevator means.

Claim 6

An apparatus according to claim 3 including selectively operable means for moving said stop means to itS operative position, means for sensing the presence of a tray in the path of movement of said stop means and for preventing movement of said stop means to its operative position until the tray has cleared the path of movement of the stop means.

Claim 7

An apparatus according to claim 5 wherein said selectively operable means for moving said stop means to its operative position includes means for sensing a back-up of trays at a selected location along the outlet conveyor means in the tray conveyor system.

Claim 8

An apparatus according to claim 1 including means operative in response to advance of a tray along said overhead conveyor means to a position above said elevator means for operating said transfer means to discharge a tray from said overhead conveyor onto a stack on said elevator means, stack conveyor means adjacent the lower end of said elevator means for conveying a stack of trays laterally away from the elevator means, and means operative when a preselected number of trays has accumulated in the stack for operating said elevator means to lower the stack onto said stack conveyor means.

Claim 9

An appratus according to claim 1 wherein said transfer means includes an elongated shoe engageable with the top of the trays on said overhead conveyor means for disengaging the trays from said overhead conveyor means.

Claim 10

An apparatus according to claim 1 wherein said tray transfer means includes a magnetic pickup head mounted for movement between a lower position engaging a tray at the upper end of the stack and a raised position to transfer the top tray from the stack to the overhead conveyor means.

Claim 11

An apparatus according to claim 9 including means for sensing the presence or absence of a tray on the overhead conveyor means and for preventing operation of said transfer means until a tray on the overhead conveyor means has cleared a position above the elevator.

Claim 12

An apparatus according to claim 9 including stack conveyor means adjacent the lower end of said elevator means for advancing a stack of articles to the elevator means, means for sensing depletion of the stack on the elevator means to a preselected minimum for operating said stack conveyor means to advance a succeeding stack of trays to the elevator means, and means operative when the stack of articles on the elevator means is exhausted for driving the elevator means to pick up said succeeding stack of trays.

Claim 13

An apparatus according to claim 11 including means for sensing the presence or absence of a tray on said overhead conveyor means, and means for preventing operation of said tray transfer means when a tray is on the overhead conveyor means above the elevator means.

Claim 14

An apparatus according to claim 10 including means for sensing a back-up of trays on the outlet conveyor means, and means operated by said last-mentioned sensing means for stopping the overhead conveyor means.

Claim 15

A tray stacking apparatus for use in a recirculating loop baking tray conveyor system for stacking baking trays and the like of ferromagnetic material comprising: said recirculating loop baking tray conveyor system including inlet and outlet tray conveyor sections each adapted to underlie and support trays at a selected level adjacent a stacking station and having adjacent ends spaced apart a distance substantially greater than the length of a tray, elevator means at said stacking station for supporting an upright stack of trays, said stack elevator means including laterally spaced endless chains extending vertically downwardly from adjacent said preselected level at relatively opposite sides of the path of travel of the trays on the overhead conveyor means, said laterally spaced chains having stack supports at spaced locations therealong adapted to underlie and support the lowermost tray in a stack disposed between the chains, means for sensing the level of the top of the stack of trays between said chains, and elevator drive means responsive to said stack level sensing means for driving said chains in a direction to lower the stack until the top tray in the stack is at a level slightly below said selected level, said baking tray conveyor system including an endless type overhead conveyor means having a lower run spaced above said selected level a distance approximating the height of a tray and extending from said one end of the inlet tray conveyor section over said elevator means to said outlet tray conveyor section, magnetic means cooperable with said lower run of said overhead conveyor means for magnetically holding the top of a ferromagnetic tray against the lower run for advance therewith, means mounting said overhead conveyor means for vertical adjustment relative to said inlet and outlet conveyor sections and to said stack elevator means to position the overhead conveyor means at a level above said selected level of said inlet and outlet tray conveyor sections a distance corresponding to the height of the baking trays to allow the trays to move from the inlet conveyor section along the lower run of the overhead conveyor and onto the outlet conveyor section for recirculating the trays, a tray stop mounted for movement between an operative position in the path of movement of the trays on said overhead conveyor and an inoperative position out of the path of movement of the trays on the overhead conveyor, said stop means in said operative position thereof being arranged to stop trays on the overhead conveyor above said elevator means, and tray ejector means, and means operable when a tray is advanced on the lower run of said overhead conveyor means to a position over a stack on said elevator means and against said tray stop for operating said tray ejector means to discharge the tray from the overhead conveyor means onto the stack.

Claim 16

A tray stacking apparatus for use in a recirculating loop baking tray conveyor system for stacking baking trays and the like of ferromagnetic material comprising: said recirculating loop baking tray conveyor system including inlet and outlet tray conveyor sections each adapted to underlie and support trays at a selected level adjacent a stacking station and having adjacent ends spaced apart a distance substantially greater than the length of a tray, elevator means at said stacking station for supporting an upright stack of trays, said stack elevator means including laterally spaced endless chains extending vertically downwardly from adjacent said preselected level at relatively opposite sides of the path of travel of the trays on the overhead conveyor means, said laterally spaced chains having stack supports at spaced locations therealong adapted to underlie and support the lowermost tray in a stack disposed between the chains, means for sensing the level of the top of the stack of trays between said chains, and elevator drive means responsive to said stack level sensing means for driving said chains in a direction to lower the stack until the top tray in the stack is at a level slightly below said selected level, said baking tray conveyor system including an endless type overhead conveyor means having a lower run spaced above said selected level a distance approximating the height of a tray and extending from said one end of the inlet tray conveyor section over said elevator means to said outlet tray conveyor section, magnetic means cooperable with said lower run of said overhead conveyor means for magnetically holding the top of a ferromagnetic tray against the lower run for advance therewith, means mounting said overhead conveyor means for vertical adjustment relative to said inlet and outlet conveyor sections and to said stack elevator means to position the overhead conveyor means at a level above said selected level of said inlet and outlet tray conveyor sections a distance corresponding to the height of the baking trays to allow the trays to move from the inlet conveyor section along the lower run of the overhead conveyor and onto the outlet conveyor section for recirculating the trays, a tray stop mounted for movement between an operative position in the path of movement of the trays on said overhead conveyor and an inoperative position out of the path of movement of the trays on the overhead conveyor, said stop means in said operative position thereof being arranged to stop trays on the overhead conveyor above said elevator means, and tray ejector means, and means operable when a tray is advanced on the lower run of said overhead conveyor means to a position over a stack on said elevator means and against said tray stop for operating said tray ejector means to discharge the tray from the overhead conveyor means onto the stack.

Claim 17

A tray stacking apparatus according to claim 14 wherein said tray ejector means includes an elongated shoe engageable with the top of a tray on said overhead conveyor means along at least a major portion of the length of the tray, and means for vertically moving said shoe to eject a tray from the lower run of said overhead conveyor means.

Claim 18

A tray stacking apparatus according to claim 14 including means responsive to a back-up of trays on the outlet tray conveyor means for moving said stop means to its operative position.

Claim 19

A tray unstacking apparatus for use in a recirculating loop baking tray conveyor system for unstacking baking trays and the like of ferromagnetic material comprising: said recirculating loop baking tray conveyor system including inlet and outlet tray conveyor sections adapted to underlie and support the trays at a selected level adjacent an unstacking station and having adjacent ends spaced apart a distance greater than the length of a tray, elevator means at said stacking station for supporting an upright stack of trays, said stack elevator means including laterally spaced endless chains extending vertically downwardly from adjacent said preselected level at relatively opposite sides of the path of travel of the trays on the overhead conveyor means, said laterally spaced chains having stack supports at spaced locations therealong adapted to underlie and support the lowermost tray in a stack disposed between the chains, means for sensing the level of the top of the stack of trays between said chains, and elevator drive means responsive to said stack level sensing means for driving said chains to raise the stack until the top tray in the stack is at a level slightly below said selected level, said baking tray conveyor system including an endless type overhead conveyor means having a lower run overlying said elevator means and extending from said inlet conveyor section to said outlet tray conveyor section and spaced thereabove a distance approximating the height of a tray, magnetic means cooperable with said lower run of said overhead conveyor means for magnetically holding the top of a ferromagnetic tray against the lower run for advance therewith, means mounting said overhead conveyor Means for vertical adjustment relative to said inlet and outlet conveyor sections and to said stack elevator means to position the overhead conveyor means at a level above said selected level of said inlet and outlet tray conveyor sections a distance corresponding to the height of the baking trays to allow the trays to move from the inlet conveyor section along the lower run of the overhead conveyor and onto the outlet conveyor section for recirculating the trays, tray transfer means including a magnetic pickup head mounted for movement between a lower position engaging the top tray in the stack and a raised position adjacent said lower run of the overhead conveyor means to transfer a tray from the stack to the overhead conveyor means, tray sensing means for sensing the presence of a tray on said overhead conveyor means in a zone between a location substantially in advance of the elevator means to a location beyond the outlet side of said elevator means, drive means operable to drive said pickup head from said raised position to said lower position and back, and means responsive to said tray sensing means for controlling said drive means to prevent operation of said tray transfer means when a tray is in said zone.

Claim 20

A tray unstacking apparatus for use in a recirculating loop baking tray conveyor system for unstacking baking trays and the like of ferromagnetic material comprising: said recirculating loop baking tray conveyor system including inlet and outlet tray conveyor sections adapted to underlie and support the trays at a selected level adjacent an unstacking station and having adjacent ends spaced apart a distance greater than the length of a tray, elevator means at said stacking station for supporting an upright stack of trays, said stack elevator means including laterally spaced endless chains extending vertically downwardly from adjacent said preselected level at relatively opposite sides of the path of travel of the trays on the overhead conveyor means, said laterally spaced chains having stack supports at spaced locations therealong adapted to underlie and support the lowermost tray in a stack disposed between the chains, means for sensing the level of the top of the stack of trays between said chains, and elevator drive means responsive to said stack level sensing means for driving said chains to raise the stack until the top tray in the stack is at a level slightly below said selected level, said baking tray conveyor system including an endless type overhead conveyor means having a lower run overlying said elevator means and extending from said inlet conveyor section to said outlet tray conveyor section and spaced thereabove a distance approximating the height of a tray, magnetic means cooperable with said lower run of said overhead conveyor means for magnetically holding the top of a ferromagnetic tray against the lower run for advance therewith, means mounting said overhead conveyor Means for vertical adjustment relative to said inlet and outlet conveyor sections and to said stack elevator means to position the overhead conveyor means at a level above said selected level of said inlet and outlet tray conveyor sections a distance corresponding to the height of the baking trays to allow the trays to move from the inlet conveyor section along the lower run of the overhead conveyor and onto the outlet conveyor section for recirculating the trays, tray transfer means including a magnetic pickup head mounted for movement between a lower position engaging the top tray in the stack and a raised position adjacent said lower run of the overhead conveyor means to transfer a tray from the stack to the overhead conveyor means, tray sensing means for sensing the presence of a tray on said overhead conveyor means in a zone between a location substantially in advance of the elevator means to a location beyond the outlet side of said elevator means, drive means operable to drive said pickup head from said raised position to said lower position and back, and means responsive to said tray sensing means for controlling said drive means to prevent operation of said tray transfer means when a tray is in said zone.

Claim 21

A tray unstacking apparatus according to claim 17 including means for sensing a back-up of trays on said outlet tray conveyor section, and means responsive to said last-mentioned means for stopping said overhead conveyor means.

Claim 22

A tray unstacking apparatus according to claim 17 including, stack conveyor means operable to advance a stack into position between said laterally spaced endless chains of said elevator means, means responsive to depletion of the stack on the stack supports to a preselected minimum for operating said stack conveyor means to advance a stack to said elevator means, and means operative when the stack on the elevator means is exhausted for operating the elevator means to pick up a succeeding stack from the stack conveyor means.