DOUTHNUT MAKING MACHINE AND PROCESS FOR MOVING OBJECTS THROUGH A FRYING TANK

Abstract: A small, inexpensive doughnut fryer has a conveyor (28) and separate elevator (32) that are driven from the same shaft without interference with one another. Sprockets (40) for driving the elevator are recessed to receive rods (30) from the conveyor. The entire conveyor assembly is provided with a quick release coupling (20) to the power supply. A method and apparatus for moving objects to be fried through a hot frying liquid by producing intermittent waves and eddies in the liquid in the desired direction of travel to propel the objects in a straight line.

Description: The present invention relates to a doughnut machine according to the precharacterizing part of claim 1. In a doughnut frying machine as known from GB-A-2074847 a horizontal conveyor having lateral bars is driven by a shaft located below the level of the hot liquid. A second and upwardly inclined chain conveyor continues the conveying path upwardly toward the discharge zone of the frying machine. The chain conveyor is driven by means of an additional and externally located chain drive which derives the rotational motion from the drive shaft of the first conveyor. In a doughnut frying apparatus as known from US-A-41765990 a horizontally arranged chain conveyor with lateral flights is extended over an upwardly inclined discharge and drain conveying section within which a second belt conveyor is provided. The belt conveyor supports the flights of the chain conveyor along the discharge conveying section. Both conveyors are operated with the same speed. In a further doughnut frying machine as known from US-A-­ 3283695 two separated conveying units are provided one behind the other. An intermediate drive chain connects the horizontal conveying unit with the drive shaft of the secondary conveying unit. In a doughnut fryer as know from US-A-3504619 one chain conveying means is provided which extends over a horizontal section in the hot liquid and an upwardly inclined discharge section. The chain conveyor is equipped with shovel-like conveying elements. In the discharge conveying section slide rails support the fried doughnuts. It is a task of the invention to provide a doughnut frying machine as disclosed having a minimum number of components in order to be marketable. This can be achieved with the help of the features in the characterizing clause of claim 1. According thereto the bar conveyor pushing the doughnuts through the frying tank is driven from the same shaft as the elevator conveyor. This reduces the drive mechanisms necessary for both conveyors. The sprockets for the bar conveyor and the elevator conveyor that are coupled to the common shaft are uniquely modified so that the conveyor sprockets can be of different pitch circles giving the elevator conveyor a slightly faster speed than the bar conveyor, but which enable the bars of the bar conveyor to move around the common shaft without interfering with the sprockets for the belt elevator conveyor the bar conveyor overlies the endless belt elevator conveyor, both of which are driven from a common shaft but at different speeds and with the bars being able to pass around the shaft and the sprockets for the belt elevator without interference. According to the embodiment disclosed in depending claim 2 the entire conveying system can be lifted as an integral unit out of the frying tank while simultaneously decoupling the driving shaft from the power supply from the driven shaft for both conveyors with one simple sliding movement. This greatly simplifies the construction of the machine and makes safer the disassembly of the machine for cleaning at the end of each operation. A further important feature is disclosed in depending claim 4. A difficultly in moving objects to be fried through the hot frying liquid is that the heating element at the bottom of the tank creates eddy currents in the liquid which cause the objects to circulate in irregular paths. This moves the objects out of their straight alignment transverse to the desired path of movement through the frying tank. The objects then tend to bunch up and become jammed within the conveyor. When the objects are brought to the flipper to invert them for frying the uncooked sides, the flipping is not successfully accomplished if the objects are not perfectly aligned in a transverse row by imparting intermittent wave motions to the liquid the wave motion propels the objects forward in a row and overcomes the cross motions caused by heat eddy currents. By intermittently driving the bar conveyor furthermore a wave is created at the leading edge of a pushing bar and simultaneously an eddy pulling current or a void-type pulling action is produced at the trailing edge of the next forward bar. This combination of a rearward pushing wave and a forward pulling current, if carried out intermittently through the lenght of the frying tank, keeps the floating objects aligned consistently in a transverse row so they are in optimum alignment when they reach the flipper and do not tend to become out of alignment at any area in the tank. A preferred embodiment of a doughtnut frying machine according to the invention will subsequently be described in connection with the drawings. In the drawings is Figure 1 an exploded, isometric view of a frying machine, Figure 2 an enlarged, isometric view of a portion of the frying machine of figure 1, Figure 3 a fragmentary cross-section through the driven shaft of the conveyor system in the machine according to figures 1 and 2, and Figure 4 partially an axial section through a shaft coupling illustrating the simplified mechanism for disconnecting the driven shaft from the driving shaft. The fryer comprises a base 10 in which is fitted a removable frying tank 12. Liquid is kept hot in the frying tank by a heating element 14 coupled to a control console 16. A conveyor assembly 18 is also removably fitted into the tank 12 and is drivingly coupled to the driving shaft 20 of a power supply within the console 16. The details of operation and construction of the basic components of the frying machine are shown in U.S. Patent 4, 346,649, the description of which is incorporated herein by reference thereto. Doughnuts or other objects to be fried are dropped from a hopper or cutter (not shown) into the inlet or left end of the frying tank (as viewed in Figure l). The cutter deposits the doughnuts at one or more laterally spaced locations in the tank generally in a transverse row. The doughnuts are moved through the tank, inverted, and then removed for cooling. The conveyor assembly 18 includes a pair of side frames 24 (figure 2) coupled together by spacer bars 26. Mounted within the side frames is an elongated bar conveyor 28 having two endless chains 29 with a plurality of pusher bars 30, spaced equidistantly along the runs of the endless chains. An elevator link belt 32 is also mounted in the side frames and runs parallel to an upwardly inclined section of the conveyor 28. The bars 30 thus move up in parallelism and slightly above the elevator belt. It is a unique feature of this invention that both the conveyor 28 and the elevator belt 30 are driven by sprockets mounted on a common shaft 36. This shaft is provided with a set of belt sprockets 40 (Figure 3) and a set of conveyor sprockets 38. The belt sprockets are slightly larger in circular pitch so as to move the belt 32 at a slightly increased velocity over the velocity of the conveyor. As best shown in Figure 3, the sprockets 40 are each cut away with a recess 42. The recesses 42 are all coaligned. The bars 30, as they reach the top of the elevator belt and come into engagement with the sprockets 38, move into the recesses 42 so that they do not actually engage any surface of the sprockets 40. This enables the bar to move rotationally relative to the sprockets 40, but not interfere with the motion of the sprockets. Thus the common simplified, inexpensive drive is suitable for operat­ ing two separate conveyors at two separate speeds without interference with one another. Another unique feature of the invention is the way the entire conveyor assembly can be removed and decoupled from the driving shaft 20. As best shown in Figures 2 and 4, the driving shaft is provided with a ball 48 and a radial protruding pin 49. The driven shaft 36 is provided with a socket 50 having an opening 52 and an elongated, longitudinal slot 54. When the conveyor socket and the driving shaft ball are in the position as shown in Figure 4, the entire conveyor assembly can be lifted as one integral unit and slid out from driving engagement with the driving shaft. The ball enables the socket to rotate clockwise as shown in Figure 4, and the pin is free to slide within the slot until the conveyor assembly can then be moved to the left, as shown by the arrow 56 and the drive is disengaged. To reengage the drive the opposite motion is employed. This greatly simplifies the drive disconnection for ease of cleaning and reassembling. A flipper mechanism 60 is employed essentially as in Patent 4,346,649. The flipper includes a channel 62 which is engaged by the bars 30. The bar 30 as it then moves past the flipper rotates the flipper to invert a doughnut in the frying liquid. A cam 64 is provided with a flattened surface against which rests a weighted arm 66. The arm rests on the flat surface of the cam to position the flipper in perfect alignment, as shown in Figure 2. After a doughnut has been inverted and the flipper falls back, the weighted arm guides the cam to restore the alignment position of the flipper. A unique feature of the invention is the tech­ nique by which doughnuts are moved through the hot liquid without bunching up or becoming misaligned out of a trans­ verse row as they approach the flipper. The heating element 14 creates fluid currents within the frying liquid. These currents tend to be circular and will impart a motion to the objects floating in the frying liquid tending to move then out of their initial transverse alignment. In this invention the drive to the driving shaft 20 is accom­ plished by a conventional electric AC motor which is operated through a timing switch such that the motor is operated only after a certain interval and in a repetitive manner. Thus the drive moves at a constant speed but inter­ mittently. The intermittent motion is timed to correspond to the dropping of doughnuts or other objects to be fried into the gap between two bars, the objects being dropped in a transverse row. As the first intermittent pulse of move­ ment occurs, the next rearwardmost bar creates a forwardly moving wave in the hot liquid. This wave impels the dough­ nuts forwardly toward the next most forward bar. The force is strong enough to overcome any crosscurrents created by the hot eddy currents in the liquid. It is also found that the forward motion of the next forwardmost bar creates a small eddy pulling current or forwardly directed void which pulls the forwardly moving dougbnuts toward the next forwardmost bar. This action results in the doughnuts being advanced from rearward bar to forward bar with each impulse with the doughnuts seldom moving very far rearwardly, but rather tending to follow the forward movement of the next forward bar. It has been found that this motion, particularly for smaller objects where there are several aligned in a row, uniquely keeps the objects in the transverse row while they are moved completly through the conveyor, including the alignment as they are brought into engagement with the flipper. In overall operation, the hopper is swung back and forth across the tank and is coupled to a link 70 that is moved in synchronysm with the rotation of the driven shaft 36. The hopper thus deposits the doughnut dough into the gap between two bars. Upon the next intermittent pulse of movement, the conveyor bars push the dougbnuts forwardly to the right, as seen in Figure 2. As the doughnuts reach the flipper, the next forwardmost bar causes the flipper to invert the doughnuts. The bars continue to propel the doughnuts to the elevator belt 32 where they are raised out of the liquid and where they may drain excess liquid. Finally, the elevator belt deposits the doughnuts on a take-away ramp 74.

Claims: 1. In a doughnut machine having a frying tank (12) for holding hot liquid, a doughnut conveyor (28) for moving doughnuts through the tank, conveyor drive means (20), and a flipper (60) for inverting the doughnuts, said doughnut conveyor including a horizontal main section, an inclined section, and a plurality of transverse pusher bars (30) characterizted by: a separate elevator conveyor (32) having an upper run parallel to said inclined section of said doughnut conveyor (28); said conveyor drive means (20) including a shaft (36), a set of doughnut conveyor sprockets (38) fixed to said shaft (36), a set of elevator conveyor sprockets (40) having a pitch different from said doughnut conveyor sprockets (38) fixed to said shaft (36); and means for guiding said bars (30) about said elevator conveyor sprockets (40) while maintaining the bars (30) in the pitch of the doughnut conveyor sprockets (38). 2. The machine of claim 1, characterized by said drive means (20) including a socket (50) fixed to an end of said shaft (36), said socket (50) having an opening (52) and a slot (54) in a wall of said socket (50), and a ball drive member (48) slidably received in said opening (52) and having a drive pin (49) drivingly engageable in maid slot (54), and wherein the shaft (36) end conveyors (28,32) can be disengaged from the ball drive member (48) by tilting the shaft (36) and socket (50) to rotate the socket so that the slot (54) in the socket sidewall can then be slipped past the pin (49). 3. The machine of claim 1, characterized by said means for guiding the bars (30) about said elevator conveyor sprockets (40) including recesses (42) in said elevator conveyor sprockets (40) extending below the teeth of the elevator conveyor sprockets (40) and aligned with one another to receive a bar (30) as the bar travels around both the doughnut conveyor sprockets (38) and the elevator conveyor sprockets (40). 4. The machine of claim 1, characterized wherein the drive means (20) operates intermittently but at a generally constant speed. 5. A process for moving small food objects through a hot liquid in a frying tank by a pusher bar conveyor, comprising: heating the liquid in the tank to a frying temperature and creating liquid currents in the liquid; placing the objects into the liquid in front of the bars of the conveyor; characterized by intermittently moving the bars at a generally constant speed through the liquid, for creating repetitive wave motions in the liquid to push the objects toward the next forward bar and overcoming the heat created liquid currents in the liquid thereby moving the objects in a straight path through the liquid to avoid misalignment. 6. The process of claim 5 characterized by said stop of intermittently moving the bars including creating an eddy pulling current behind the next most forward bar to draw the objects forward toward the next most forward bar with each intermittent motion of the bars.

Inventors: BELSHAW, THOMAS E., WILKE, WILBUR D., WOODWORTH, FREDERICK G.
Applicants: BELSHAW BROS., INC.
Application year: 1986
Main classification: A21B5
IPC codes: A21B5, A47J37