Apparatus and method for distributing a particulate charge over an article

Abstract: Apparatus for distributing a charge, such as cheese, falling onto an article, such as a pizza. The apparatus comprises a baffle (36) which deflects at least a portion of the charge radially outwardly; a director (41) arranged upstream of the baffle for directing at least a portion of the charge radially inwardly onto the baffle; and a guide (28) arranged downstream of the baffle for deflecting at least a portion of the charge radially inwardly whereby the charge falls onto and is distributed across the article.

Description: The present invention relates to a method and apparatus for distributing a charge as it falls towards an article. A conventional system for distributing a particulate charge as it falls towards an article is disclosed in US-A-5109760. A conical screen is supported above a pizza upon which cheese is to be deposited. Cheese particles are dropped in a mass upon the screen and distributed by gravitational force in an even pattern over the pizza. The conical screen has a baffle portion at an upper region of the screen, a circular opening at the apex of the baffle, and a screen with screen openings at a lower region of the screen. The conical screen is mounted in a cylinder with a gap between the outer periphery of the screen and the cylinder. Cheese particles deposited upon the pizza will either have fallen through the opening in the apex of the screen, the screen openings, or the gap between the screen and the cylinder. An alternative system is described in US-A-5678476. A food feed hopper is mounted above a food spreader housing having movable paddles therein and a porous bottom member spaced above the surface upon which the food is to be spread. A problem with the system of US-A-5109760 and US-A-5678476 is that the product can be unevenly distributed. In particular it is difficult to direct product to the centre of the article. US-5109760 attempts to address this problem by providing a circular opening at the apex of the baffle so that the product in the centre falls straight through. A still further system is disclosed in US-A-3 820 503. In accordance with a first aspect of the present invention there is provided apparatus for distributing a charge falling onto an article, the apparatus comprising a baffle which deflects at least a portion of the charge radially outwardly, relative to the direction in which the charge is falling; a director arranged upstream of the baffle for directing at least a portion of the charge in a radially inward direction, relative to the direction in which the charge is falling, onto the baffle; and a guide arranged downstream of the baffle for deflecting at least a portion of the charge radially inwardly, relative to the direction in which the charge is falling, whereby the charge falls onto and is distributed across the article. In accordance with a second aspect of the present invention there is provided a method of distributing a charge falling onto an article, the method comprising directing at least a portion of the charge in a radially inward direction, relative to the direction in which the charge is falling, onto a baffle with a director arranged upstream of the baffle; deflecting at least a portion of the charge radially outwardly, relative to the direction in which the charge is falling, with the baffle; and deflecting at least a portion of the charge radially inwardly, relative to the direction in which the charge is falling, with a guide arranged downstream of the baffle whereby the charge falls onto and is distributed across the article. The invention provides an alternative method of directing the charge towards the centre of the article. US-A-5109760 directs particles towards the centre of the article by the provision of an opening in the baffle. In contrast, the present invention deflects a portion of the charge towards the centre of the article using a guide arranged downstream of the baffle. The effect of the baffle is enhanced by directing at least a portion of the charge so that it is moving with a radially inward component as it strikes the baffle. This increases the angle of deflection of the baffle. The invention results in a number of advantages. Firstly the invention enables the baffle to present a continuous deflection surface to the charge, in contrast to US-A-5109760 where the baffle requires a central opening. As a result the baffle is more easily constructed, easier to support and easier to clean. Secondly, it has been discovered that surprisingly the distribution can be conveniently controlled by adjusting the relative positions of the baffle and the guide. In contrast, in US-A-5109760 the particle distribution is fixed by the form of the conical screen. The baffle may deflect the charge by rotating about a vertical axis. However preferably the baffle has an outwardly angled deflection surface which deflects the charge radially outwardly. The baffle can then deflect the charge radially without moving. The deflection surface can be suitably shaped to provide a desired distribution. Where a circumferentially uniform distribution is required (e.g. on a pizza) then preferably the deflection surface is substantially frustoconical. Typically the guide and/or baffle are adjustably mounted whereby the relative positions of the guide and the baffle can be adjusted to achieve a desired distribution. In one example the baffle is slidably mounted on a baffle support and locking means is provided to lock the baffle at a required position. In another example the baffle has a threaded bore which receives a threaded baffle support and the baffle is moved by screwing it up or down the threaded baffle support. In US-A-5109760 the conical screen is supported by ledge pins which extend radially towards the screen. It is not possible to suspend the screen from above since this would obscure the central opening at the apex of the screen. In contrast, the baffle in the present invention can be supported by a baffle support which extends towards the baffle from a position upstream of the baffle. In this case the baffle and the baffle support together present a continuous deflection surface to the falling charge. This support arrangement is simple and more sturdy than in US-A-5109760. The director may comprise a set of air jets which direct the charge radially inwardly onto the chute. Alternatively the director may comprise a chute having inwardly tapering walls which define a convergence position, wherein the baffle is arranged at least partially upstream of the convergence position. As a result, at least a portion of the charge is converging as it- strikes the baffle. The chute is typically frustoconical, although alternative tapering shapes could be used. Typically the apparatus further comprises a second baffle arranged upstream of an outlet of the chute for deflecting the charge radially outwardly. The second baffle also acts to break up the main mass of the charge. The guide may be fixed, or the apparatus may further comprise means for moving the guide to and from a masking position adjacent to or abutting with the article whereby the charge falls onto the article with a border defined by the guide. In a preferred example the guide comprises a fixed outer cylinder and a movable inner cylinder which can be moved to and from the article. The guide and chute may be formed integrally, but preferably they are separated by a gap. This provides access to the interior of the system and enables the relative positions of the guide and chute to be adjusted. The charge may comprise any suitable charge which can be deflected by the guide and the baffle. The charge is typically particulate and the particles may have a variety of sizes ranging from powdery or granular particles to even larger particles. In a preferred example the charge comprises particles of food. For example the charge may comprises breadcrumbs, or a pizza topping such as cheese, pepperoni, mushrooms etc. The article may be inedible (for example a plate or baking tray) but in a preferred example the article comprises an article of food such as a pizza base. Embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a front view of a first embodiment for depositing cheese onto pizza bases; Figure 2 is a side view of the apparatus of Figure 1; Figure 3 is a plan view of the shutter mechanism of Figure 1; Figure 4 is a side view partially in section of the distribution apparatus of Figure 1; Figure 5 is a cross section through the apparatus of Figure 1 showing one of two drive mechanisms for driving the inner cylinder; Figure 6 shows one of the clamp assemblies of Figure 1 in detail; Figure 7 is a schematic side view partially in section of the distribution apparatus of Figure 1 showing a charge falling onto a pizza base; Figure 8 is a view similar to Figure 1 but of a second example; and, Figure 9 is a plan view of the spreader system of Figure 8. Referring to Figures 1 and 2, a series of pizza bases 1 are transported on a conveyor 2 to a deposition position 3. Mounted above the position 3 on a frame 4 is a dosing system comprising a combinational weigher 5, and a distributer 6. The combinational weigher 5 comprises a funnel 7 into which grated cheese is fed. The cheese falls down a cone shaped dispersion device 8 onto a number of weighing units 9-12 which are distributed around the periphery of the device 8. Each weighing unit 9-12 includes a trough-shaped dispersion feeder 9a-12a coupled with an electromagnetic vibrator 9b-12b. Each weighing unit 9-12 also includes a pool hopper 9c-12c into which the grated cheese is supplied via the troughs 9a-12a as they are vibrated, each pool hopper opening via a respective gate into a weigh hopper 9d-12d. Each weigh hopper 9d-12d is coupled with a respective scale cell (not shown) so that the weight of their contents can be determined. The combinational weigher described above is conventional and examples are described in more detail in, for example, EP-A-0818669. When the controlling microprocessor (not shown) of the combinational weigher 5 determines that a desired weight of grated cheese is located in a particular combination of the weighers 9d-12d, the weigher gates (not shown) of the selected weighers are opened so that their contents empty into chutes 13-16 which guide the cheese into a timing hopper 17 (shown in detail in Figure 4). The timing hopper 17 has a pair of pivoting doors 18, 19. At a suitable point in the cycle, the doors 18,19 are opened to release the charge onto an iris-type shutter mechanism 70. Figure 3 is a plan view of the shutter mechanism 70. Three identical horizontal shutter blades 71-73 are shown in full lines in their closed position, and in chain-dotted lines in their fully open position. They are pivotally mounted on a base 74 by pivot pins 75,76,77. Shutter mechanisms of the type illustrated in Figure 3 are described in more detail in EP-A-0787431, GB-A-2288595 and WO-A-9529108. When a pizza 1 is at the position 3, the shutter blades 71-73 are rapidly opened so that the cheese is relatively undisturbed and falls directly downward into the distribution apparatus 6 over an area substantially equal to the area of the upper surface of the shutter blades 71-73. Referring to Figure 4, the distributer 6 comprises a chute 20 in the form of an inverted frustocone, and a cylinder assembly 80. The cylinder assembly 80 and chute 20 are mounted on a pair of vertical support arms 22,23 which are suspended from the frame 4 (Figure 2). Figure 5 is a section through the upper part of the cylinder assembly 80. The assembly comprises an outer cylinder 21 which is rigidly mounted to the support arms 22,23 by support pins 81-84 shown in Figure 2. The outer cylinder 21 has an inner diameter of 300mm although this will vary depending on the size of the pizzas. A pneumatic drive mechanism 85 is bolted to the outer cylinder 21 via bracket 86. The drive mechanism has a drive arm 87 which is bolted to an inner cylinder 28 via bracket 88. The inner cylinder 28 has an internal diameter of 270mm (suitable for 12" pizzas). The inner cylinder 28 is driven between a raised position (shown in dashed lines) and a lowered position (shown in solid lines) by the drive mechanism 85. An identical drive mechanism (not shown) is also provided on the opposite side of the cylinder assembly 80. Three clamp assemblies are provided for clamping the pizza base 1 in the position 3 below the cylinder assembly 80. The clamp assemblies are distributed at equal angular distributions around the periphery of the cylinder assembly 80. One of the three clamp assemblies 24 is shown in Figures 1 and 4. Another one of the clamp assemblies 89 is shown in detail in Figure 6. A pneumatic cylinder 90 is pivoted on a bracket 91 which is bolted to the outer cylinder 21. The drive rod 92 of the cylinder is pivotally attached at 93 to a pivoting arm 94. The pivoting arm 94 is pivotally attached to a bracket 95 which is bolted to the outer cylinder 21. The pivoting arm 94 is shown in its upper and lower positions in dashed and full lines respectively. An actuating arm 96 is pivoted to the pivoting arm 94 at 97, and to a second pivoting arm 98 at 99. The end of the actuating arm 96 carries a curved clamping segment 100, shown in full lines in its lowered clamping position and in dashed lines its raised position. As the drive rod 92 extends, the clamping segment 100 is lowered to its clamping position in which it engages the outer edge of a pizza base 1. When a pizza base 1 is in position, the three clamping segments are pivoted into position using the cylinders 90 and the inner cylinder 28 is moved down using the drive mechanism 85 until it abuts the pizza base 1. Referring back to Figure 4, a suspension rod 31 having an angled portion 32 and a vertical portion 33 is mounted to the chute 20 at 34. A pair of conical baffles 35, 36 are threaded onto the vertical portion 33 of the suspension rod 31, and locked into place with a respective collar 37,38 and locking pin (not shown). The baffles 35,36 can be moved up and down by releasing their respective locking pin and sliding the baffle up or down the support arm 31 to a required position. The angle of the deflection surface of the upper baffle 35 is greater than the angle of the deflection surface of the lower baffle 36. The baffles 35,36 have solid deflecting surfaces and, together with the suspension rod 31, present a continuous deflection surface to the falling charge (ie. there is no central hole as in US-A-5109760). Figure 7 illustrates the principal of operation of the distributor 6. When a pizza base 1 is in position and clamped in place, the inner cylinder 28 is moved down to its masking position, and the shutter blades 71-73 (not shown) are opened to release a charge into the distributor 6. As the charge is released, a portion of the charge hits the upper baffle 35 (as indicated by arrows 42-44), a portion (indicated by arrows 45-47) hits the tapered inner wall 41 of the chute 20 directly without hitting the upper baffle 35, and a portion (indicated by arrow 48) falls unimpeded through the outlet 49 of the chute 20. The upper baffle 35 acts to break up the main mass of the charge and push it out to the sides of the chute 20. The lower baffle 36 is positioned downstream of the chute 20 between the outlet 49 of the chute 20 and a convergence position (indicated generally at 50) which is defined by the convergence point of the tapered inner wall 41 of the chute 20. As a result, at least part of the charge converges radially inwardly onto the lower baffle 36, as indicated by arrow 52. The lower baffle 36 then deflects a portion of the charge out to the sides of the cylinder as indicated by arrow 51. The charge is contained by the cylindrical inner wall of the inner cylinder 28, and some is deflected back towards the centre line 53 as indicated by arrow 54. The result of the various deflections from the chute 20, baffles 35,36 and cylinder 28 is a uniform distribution across the surface of the pizza base 1. The proportions and angles of the chute 20, baffles 35,36 and cylinder 28 are selected to give consistent results. The relative sizes may be varied to allow for different charge sizes and different amounts of bounciness of the articles passing through. The positioning of the lower baffle 36 can be adjusted to allow more or less product to be gathered at the periphery or in the centre of the pizza base 1. In experiments it has been determined that as the lower baffle 36 is moved down, more cheese is deposited at the outer periphery of the pizza base 1. Alternatively the chute 41 and baffles 35,36 may be moved away from the centre line 53 to deposit the charge more towards one area of the pizza base 1. When the cheese has been deposited, the clamping segments 24,89 are rotated away from the pizza base 1 as indicated at 61,62, the inner cylinder 28 is retracted by distance A to prevent the cylinder from dislodging the deposited cheese, and the coated pizza base 1 is transported away from the deposition position 3 by the conveyor 2. In an alternative embodiment the vertical portion 33 of the suspension rod 31 may be threaded, and the baffle 35,36 may be provided with internally threaded bores. The baffles 35,36 can then be adjusted by rotating the baffles so that they move up and down the support arm on the thread. Furthermore, the combinational weigher 5 may be replaced by an alternative dosing device such as a volumetric depositor, bucket system or any other apparatus which can deliver equal charges into the timing hopper 17. With an accurate dosing device the timing hopper 17 and/or the shutter assembly 70 may not be required. If cheese collects on the angled portion 32 of the suspension arm, then the angle of the portion 32 can be increased from the angle shown in Figure 3. In a further alternative, the suspension arm 31 may extend vertically into the timing hopper 17, with a suitable central aperture being formed by the pivoting doors 19,18 and the shutter blades 71-73 to receive the suspension arm 31. In the example described above with reference to Figures 1 and 7, a single delivery system is used. In order to increase production speed, the delivery system of the previous example could be arranged to traverse above the pizza as cheese is delivered. This could be carried out with a single delivery system but in the preferred example shown in Figures 8 and 9, a double delivery system is used. This comprises a pair of distributers 6a,6b having constructions very similar to the distributer 6 of Figure 1. The distributers 6a,6b are mounted to a carriage 100 which is supported by rollers 101 on a pair of laterally spaced tracks 102 (Figure 9). The carriage is driven via a drive belt 103 which is secured to the carriage at 104. The drive belt 103 is rotated by a motor 105 to which it is coupled via a further drive belt 106 and a pulley 107. The combinational weigher 5 has the same form as shown in Figures 1 and 2 and terminates in a pair of delivery funnels 110a,110b located above entry funnels 111a,111b of the distributers 6a,6b respectfully. The exits to the delivery funnels 110a,110b are positioned so that they remain in alignment with the funnels 111a, 111b respectively throughout the lateral movement of the distributers 6a,6b. In Figure 8, the funnels 110a,110b are located at the left side of the funnels 111a,111b while following maximum movement of the carriage 100 to the left, the funnels 110a,110b will be aligned with the righthand side of the funnels 111a,111b. One group of the weighing units 9-12 is associated with the funnel 110a and another group of the weighing units is associated with the funnel 110b. In order to convey pneumatic control to the respective sets of shutter blades, a flexible delivery conduit system 112 is provided. In operation, the distributers 6a,6b are located at a home position as shown in Figure 8. As a pizza is conveyed beneath the distributers 6a,6b on a conveyer, the arrival of the first pizza is detected and the control system (not shown) which knows the speed of movement of the pizzas, waits until that pizza is aligned with a cylinder 80b of the distributer 6b and then activates the distributer to lower the cylinder 80b as previously described. The pizzas are supplied to the conveyor in such a way that when a pizza is aligned with the distributer 6b a further pizza is aligned with the distributer 6A. (The cylinder of the distributer 6A is omitted in Figure 8 for clarity). The distributers 6A,6B are then operated as previously described, but at the same time the distributers are caused to move with the pizzas by a suitable activation of the belt 103. During this movement, cheese is supplied to the pizzas. When the distributers 6A,6B reach their left most position, the cylinders 80 are retracted allowing the pizzas to continue beyond the machine while the motor 105 is activated in its opposite direction to cause the carriage 100 to return to its start position shown in Figure 8 and the process is then repeated. The advantage of this process is that it allows pizzas to be fed at high speeds of up to 35 per minute while still allowing enough time for the cheese to be distributed. In the previous example, the pizzas would need to either be stopped during the distribution stage or move more slowly to allow enough time for the cheese to be distributed.. In a further alternative which is applicable to both of the embodiments described above, the cylinder arrangement is replaced by the use of two fingers which align the pizzas.

Claims: Apparatus for distributing a charge falling onto an article, the apparatus comprising a baffle (36) which deflects at least a portion of the charge radially outwardly, relative to the direction in which the charge is falling; a director (41) arranged upstream of the baffle for directing at least a portion of the charge in a radially inward direction, relative to the direction in which the charge is falling, onto the baffle; and a guide (28) arranged downstream of the baffle for deflecting at least a portion of the charge radially inwardly, relative to the direction in which the charge is falling, whereby the charge falls onto and is distributed across the article. Apparatus according to claim 1 wherein the baffle (36) has an outwardly angled deflection surface which deflects the charge radially outwardly relative to the direction in which the charge is falling. Apparatus according to claim 2 wherein the deflection surface is substantially frustoconical. Apparatus according to claim 2 or claim 3, wherein the baffle (36) is stationary. Apparatus according to any of the preceding claims further comprising a baffle support (33) which supports the baffle (36) and extends towards the baffle from a position upstream of the baffle. Apparatus according to any of the preceding claims wherein the guide (28) and/or baffle (36) are adjustably mounted whereby the relative positions of the guide and the baffle can be adjusted to achieve a desired distribution. Apparatus according to any of the preceding claims wherein the director (41) comprises a chute having inwardly tapering walls which define a convergence position, wherein the baffle (36) is arranged at least partially upstream of the convergence position. Apparatus according to any of the preceding claims further comprising a second baffle (35) arranged upstream of the director (41) for deflecting the charge radially outwardly relative to the direction in which the charge is falling. Apparatus according to any of the preceding claims further comprising means for moving the guide (28) to and from a masking position adjacent to or abutting with the article whereby the charge falls onto the article with a border defined by the guide. An assembly for distributing a charge falling into an article, the assembly comprising an apparatus according to any of the preceding claims, the apparatus being mounted for movement with the article while the charge is distributed. An assembly according to claim 10, comprising two sets of apparatus according to any of claims 1 to 9, each set of apparatus being mounted to a common, movably mounted carriage. Apparatus or an assembly according to any of the preceding claims, further comprising a weigher located above the baffle for delivering a predetermined weight of charge. A method of distributing a charge falling onto an article, the method comprising directing at least a portion of the charge in a radially inward direction, relative to the direction in which the charge is falling, onto a baffle (36) with a director (41) arranged upstream of the baffle; deflecting at least a portion of the charge radially outwardly, relative to the direction in which the charge is falling, with the baffle (36); and deflecting at least a portion of the charge radially inwardly, relative to the direction in which the charge is falling, with a guide (28) arranged downstream of the baffle (36) whereby the charge falls onto and is distributed across the article. A method according to claim 13, further comprising adjusting the relative positions of the baffle (36) and the guide (28) to achieve a desired distribution. A method according to claim 13 or 14 wherein the step of directing comprises converging at least a portion of the charge onto the baffle with a chute (41) having inwardly tapering walls. A method according to any of claims 13 to 15 wherein the charge comprises food. A method according to claim 16 wherein the article comprises an article of food. A method according to any of claims 13 to 17, further comprising moving the article, baffle and guide together during the distribution process.

Inventors: PARSONS MICHAEL, ROWLEY JOHN THOMAS, PARSONS, MICHAEL, ROWLEY, JOHN THOMAS
Applicants: ISHIDA SEISAKUSHO, ISHIDA CO., LTD.
Application year: 1999
Main classification: A21C9
IPC codes: A21C15, A21C9