Patent GB-891426-A (GB)
Title: Continuous baking ovens
IPC: A21B1/46
Filed: 1959-12-15
Abstract: 891,426. Conveyers for bakers' ovens. WILSON, L. H. Dec. 15, 1959 [Dec. 17, 1958], No. 42522/59. Class 51 (2). [Also in Group XXX] A swing-tray oven conveyer comprises a pair of endless chains 12 between which are pivotally mounted a series of swing trays each having a lid 30 which can be raised and lowered bodily relative to the tray floor, so as to form a removable cover for pans which contain bread loaves and rest on the tray floor, or alternatively when fully lowered to rest on the tray floor to act as a platform for continental or other flat bread. The floor of the tray is formed by wires 20c stretched between transverse angle irons secured between end plates 20a, so that the hot air in the oven can reach the underside of lid 30 when lowered to form a platform. The tray has a top member 20b interconnecting the end plates 20a and having extensions 20d by which the tray is pivoted on extended link pins 20e of the opposed chains. A slot 26 is formed in each end plate 20a and is bounded by bent-up portions of the end plate to form a guideway for a stub 28 provided on each end of the lid 30, each stub having a depending plate 28a secured to it within the guideway to prevent tilting of the lid, and a roller 32 on its end for engagement with a pair of lifting arms 44 provided at an oven opening 22. The opening 22 is divided by a plate 24 into an upper loading section and a lower discharge section respectively. As the trays move upwardly past the opening they are tipped in turn by a pair of cam tracks 36 engaging rollers 34 provided one on each end plate 20a. A pivoted portion 38a of a receiving shoot 38 is raised by the tray just prior to tipping and falls back into alignment with the tray floor, or with the lid if in lowered position, as the tray becomes fully tipped (see Fig. 7). A control circuit is provided in conjunction with a driving mechanism for oscillating the arms 44 between the full and chain-line positions (Fig. 1) in timed relationship with intermittent movements of chains 12, only when the lid 30 is to be used as a cover, the arms remaining in the chain-line position when the lid is to serve as a platform for flat bread. So that the arms 44 can maintain the lid raised clear of bread pans which are normally covered by it, and remain clear throughout both the discharge of baked loaves from the tray and feeding of fresh loaves thereto which necessitates arms 44 oscillating through more than one tray pitch, each arm comprises an inner portion 44a and an outer portion 44b pivoted at 48 to the inner portion and held rigid with the latter by engagement with adjustable abutment 50 during the upstroke, whilst on the downstroke it is free to pivot clear of a following tray. The driving mechanism for the arms 44 comprises a crank 55, Fig. 2, driven by a motor 57 and connected by a rod 54 to an arm 52 secured to a shaft 46 on which the arms 44 are mounted. The connection of rod 54 to arm 52 is via a swivelling sleeve 61 in which rod 54 can slide to a limited extent against the pressure of spring 60 so that when arms 44 have raised a lid 30 to its fullest extent where stub 28 engages member 20b this engagement is maintained by the spring 60 during subsequent upward movement of the tray. A quadrant 55a integral with crank 55 cooperates with three micro-switches 64, 65, 68. Two further micro-switches 71, 72 are arranged to be operated by the corners of a hexagonal collar 70 on an extension of conveyer driving shaft 18, the angular spacing of these corners representing successive tray pitches. These micro-switches are connected in a circuit (Fig. 10, not shown) for control of motor 57 and the conveyer driving motor which includes a timer 80 to delay re-starting the conveyer after each stoppage. The circuit also includes a set of manual switches which allow an operator to set the circuit to suit the required operations of arms 44 when conveying loaves to be covered, when conveying flat bread, when changing over from flat bread to covered loaves and vice versa.