Patent GB-796025-A (GB)
Title: Improvements in or relating to bread handling apparatus
IPC: A21B3/07
Filed: 1956-03-16
Abstract: 796,025. Conveyers for bakers' ovens. BAKER PERKINS, Ltd. March 16, 1956 [March 17, 1955], No. 8338/56. Class 51 (2). [Also in Group XXX] In a bakery oven O or like unit which includes an endless tray conveyer of the kind in which the trays T are maintained horizontal throughout their travel and support baking tins P, the baking tins are pushed off the trays T on to an unloading surface whilst simultaneously fresh baking tins are pushed on to the trays from a loading surface arranged in horizontal alignment with the unloading surface, by horizontally movable transfer means adapted to engage, during its travel from a retracted position, a set of baking tins on a conveyer tray and also a set of baking tins on the loading surface and move them respectively on to the unloading surface and on to the unloaded tray. As shown, the tray conveyer comprises a pair of endless chains 11 between which the trays T are pivotally mounted. A conveyer belt 33 forming the loading surface presents the sets of tins in turn for loading on to the trays T and a receiving conveyer belt 62 forming the unloading surface receives unloaded sets of tins from the trays T. Each tray T is stopped in turn between the two conveyer belts, the intervening spaces being bridged by combs 65, 66 and a table 61. The comb 66 is pivoted for retracting movement (see below). Each tray consists of side plates 16 between which extend transverse supports 17 for a series of bars 18 with upturned ends, forming a grid, the upturned ends of the bars normally retaining a baking tin set but being arranged to mesh with the combs 65, 66 at the loading and unloading station. The rear ends of the side plates are pivoted to the chains 11, while the front end of each side plate has guide rollers 21 and 22 for respectively engaging upper and lower guide tracks 25 and 26, roller 22 also engaging a guide track 27 which extends downwards to the loading and imloading station. Beyond the station the axles 24 of the rollers 22 are engaged by a pair of star wheels 29 driven from one of the pairs of driving sprockets 15 of the chains 11. The trays are steadied at the point of engagement of the star wheels by short guide tracks 32 which are engaged by the rollers 21. The loading and unloading mechanism comprises a pair of guide tracks each in three parts 39, 39a, 39b to leave gaps for the chains 11, a carriage 40 running on the tracks by means of rear rollers 50 and front rollers 50a, 50b spaced apart a slightly greater distance than the width of the gaps between the track parts and two pusher members 43, 43a, the former being pivoted for vertical swinging while the latter is fixed. The carriage is reciprocated by a pair of pinions 45, driven by a reversible motor separate from that which drives the conveyer, engaging racks 44 on the side members of the carriage. On the forward stroke, pusher 43 is held in vertical depending position by a spring buffer 58b on the carriage, so that each pusher engages a baking tin set on the loading conveyer belt 33 and on a conveyer tray T respectively, the latter being pushed over the comb 66 and plate 61 on to conveyer belt 62 while the former is pushed on to the unloaded tray. Towards the end of this movement, a roller 54 on the pusher 43 at one side of the carriage lifts up a flap 51a. On the return stroke the roller 54 rides up this flap on to a track 51 to raise pusher 43 clear of a succeeding set of baking tins being brought up to the loading position by the belt 33, roller 54 then riding down the bent end 51b of track 51 to allow the pusher to fall gently against the buffer 58b where it is steadied by the roller 54 engaging a curved track portion 57. In operation, a number of limit switches (not shown) are provided for operation by the carriage and trays, these being arranged in circuit with the two motors to cause intermittent advancement of the chain 11 with intermediate forward and return movements of the carriage 40. At the forward limit of its movement, the roller 50a on carriage 40 engages between two fingers 69, 72 pivoted at 70 and connected by linkage 73, 74, 75 to a shaft 67 on which the comb 66 is mounted, so that the comb is pivoted downwardly out of the path of the conveyer tray just loaded. The carriage 40 commences its return movement after this conveyer tray has commenced to move, returning comb 66 to its operative position. The conveyer trays may be arranged to move upwardly past the loading and unloading station, in which case the control circuit is modified so that the return movement of the carriage 40 takes place whilst the conveyer trays are stationary, the fixed pusher 43a being replaced by a pivoted pusher having a roller engaging a lifting track similarly to the arrangement for pusher 43. Movement of the conveyer trays is arranged to take place whilst the carriage 40 is in its forward position, so that comb 66 is moved'out of the way during this movement.