Patent GB-933094-A (GB)
Title: Pan stacking and unstacking system
IPC: B65G57/00
Filed: 1960-02-08
Abstract: 933,094. Stacking and unstacking. BAKER PERKINS HOLDINGS Ltd. (Baker Perkins Inc.). Feb. 8, 1960, No. 4325/60. Class 94(1). [Also in Groups XXX and XXXII] Apparatus is provided in a bakery plant for stacking empty pans advancing on a conveyer after having discharged the baked product, and for dispensing pans from a stack on to a conveyer for filling with dough &c. Stacking apparatus. Pans Pare advanced by a conveyer 12, Figs. 1, 2 7, against a stop plate 122 operating a switch LS-1 causing a carriage 30 with a depending member 68, (see particularly Figs. 3, 7), to move transversely of the conveyer and sweep the pan on to an elevator or pan already deposited on it. The elevator comprises supports 130, 132, Figs. 1, 5, on a carriage 136 lowered in steps and raised by a hydraulic piston and cylinder motor 150. The member 68 is raised by a pneumatic motor 58 on its return stroke. When the desired count of pans is obtained, switch means is operated to fully lower the elevator so that it straddles a discharge conveyer 16 depositing the stack on it for transfer to a further conveyer 18. Cam means on the discharge conveyer 16, Fig. 1, operates switches causing stopping of that conveyer and upward return of the elevator. Photo-electric means, Fig. 11 (not shown), maintains the elevator supports in the pan receiving position and counteracts any lowering due to leakage &c. until stacking recommences. The plate 122 may be raised clear of the conveyer 12 when stacking is not desired. The discharge conveyer 16 moves the stacks to a roller conveyer 18 which is movable vertically so that it may be dropped, leaving the stacks on the arms 309 of a trolley, Fig. 13, wheeled in to straddle it. The machine is adjustable for various pan sizes. Unstacking apparatus. (Figs. 13, 17, 19). This differs from the stacking machine mainly in that gripper means removes pans from a stack raised by the elevator and deposits each on the conveyer 302. The grippers comprise two carriages 336, 338 running on rails on a support frame 322, the latter being pivoted to the machine frame at 332 above the conveyer 302 and being vertically movable at its other end by pneumatic motors 404, 406. The two carriages are joined for movement towards and away from each other by a pneumatic motor 360. The stack of pans P is raised intermittently by the elevator under control of photo-electric means, Fig. 20 (not shown), and the frame pivots downwards so that the uppermost pan lies between the two carriages. A detector 380, Fig. 19, on the carriage 336 operates means causing the motor 360 to close the carriages to grip a pan. The frame rises with the pan and both carriages are moved by a pneumatic motor 350 to the discharge position over the conveyer 302. The inlet roller conveyer 306 is similar to conveyer 18 of the stacking machine and receives stacks from a trolley 308. A feed conveyer 314 is pivoted at 316 and adjustable at its inlet end in height to receive stacks from the conveyer 306. General. The stacking and unstacking machines are described as applied to pan removal and replacement on a single conveyer forming part of a baking process circuit, Fig. 21 (not shown). Stacks of pans are stored adjacent the machines for loading and unloading by non-automatic means. Alternatively the stacker operates on the circuit conveyer while the unstacker feeds a branch conveyer, Fig. 22 (not shown), the stacks being stored on a series of parallel conveyers between the two machines and the machines being movable into alignment with any desired storage conveyers. The storage conveyers may be each in three separate sections which are capable of being driven separately in both directions to close up gaps between stacks deposited on them. The storage conveyers, may be powered and/or gravity, for example a gravity conveyer having a flight conveyer superposed on it and spring loaded so as to be operative only up to a force sufficient to move a stack may be employed. Automatic signals indicating the need to remove or supply stacks may be arranged.