Patent Application
20100275789
A conveyor toaster is a well-known cooking device that uses a vertical or near-vertical heated platen and a slowly rotating conveyor, which urges a food product against the platen while it simultaneously drags a food product downwardly and across the platen's hot surface. By virtue of its design, a conveyor toaster is able to process food products continuously as opposed to the toasters commonly used by consumers, which process food products in a batch mode.
Conveyor toasters are ill-suited for consumer use because of their size, manufacturing cost, power requirements and the time required to pre-heat the platen to operating temperature. They are preferred by restaurants and food services however that require high-volume through-put and consistent heating/toasting.
A well-known problem with prior art conveyor toasters is that heavy-gauge wire conveyors that urge a food product against the platen and which moves the food product across the platen tends to leave marks in soft food products like breads and bagels. Another problem with prior art conveyor toasters is that most of them are able to process food products of only a single thickness due to the fact that the spacing or separation distance between the actual conveyor and the heated platen is fixed. Food products that are too thin will thus fall through a prior art conveyor toaster. Food products that are too thick can jam the conveyor in place. Yet another problem with prior art conveyor toasters is that they are difficult to clean because the conveyors are fixedly attached to the toaster bodies. A conveyor toaster that was adjustable, which facilitated removal of the conveyor mechanisms and which did not leave marks on delicate food products that need to be heated or toasted would be an improvement over the prior art.
The conveyor assemblies 40A and 40B are described below and depicted in other figures. Food products to be heated or toasted using the toaster 10 are placed into the opening 24 where the food product can be “grabbed” by one of two, independently operated and independently-adjustable and independently-removable conveyor assemblies 40A and 40B (conveyors), both of which urge food products against a heated platen 26 and drag food products downwardly, across one of two corresponding heated sides of the electrically-heated platen 26, the surface temperature of which can be adjusted by changing the current delivered to one or more heating elements embedded into the platen 26. By adjusting the surface temperatures of the platen 26 and the rotation speed of the conveyors, the toaster 10 is able to heat or toast one or more food products on one side of the platen 26 while heating or toasting one or more other food products on the other side of the food platen. Food products are dragged downwardly across the platen and dropped into a food collection area 17 from which the food product is retrieved by an operator.
In a preferred embodiment, the mounting pins 38 are approximately ½ inch diameter, stainless steel pins. They extend into the space between the left end housing 14 and the right end housing 16. The mounting pins 38 also extend through the end panels 37 attached to, and which form part of the left end housing 14 and right end housing 16 of the toaster 10. The conveyor assemblies 40A and 40B hang on the mounting pins. A mechanism described more fully below translates enables an operator to move or translate the mounting pins 38 toward and away from the platen 26 to allow an operator to selectably decrease and increase the separation distance between the platen surfaces and the conveyors.
The platen 26 includes a thermal break 27 embodied as an air gap 27. Separate embedded heating elements embedded in the platen on either side of the thermal break 27 allow the two sides of the platen to be heated separately. One lateral portion of the platen (left or right side of the thermal break 27) can be heated while the other, laterally adjacent portion is either heated or unheated. The platen 26 can also be embodied as any of the platens disclosed in the applicant's co-pending patent applications identified by U.S. application Ser. No. 12/267,449 filed Nov. 7, 2008, Ser. No. 12/329,358 filed Dec. 5, 2008, Ser. No. 12/329,373 filed Dec. 5, 2008, Ser. No. 12/329,397 filed Dec. 5, 2008, and Ser. No. 12/329,413, filed Dec. 5, 2008, the contents of each is incorporated herein by reference. Using one or more such platens disclosed in the aforementioned co-pending applications in the toasters disclosed herein, it is possible to heat a first side of a food product against a first side of a platen and laterally translate the food product as shown in the aforementioned co-pending applications such that the second side of the food product is heated against an opposite side of the same platen.
The conveyor assemblies 40A and 40B are identical in that both of them are separately adjustable during operation and separately removable from the toaster 10. As can be seen in
The platen 26 has a first side 28 that faces the front or first conveyor assembly 40A and an identical opposing side 30 (not visible in
As stated above and as can be seen in figures described below, the mounting pins 38 are adjustable and configured and arranged to move horizontally, i.e., laterally toward and away from the platen 26 by the rotation of conveyor control shafts for each side of each platen and which extend out from both the left side housing 14 and the right side housing 16 but which are not visible in
As described herein, the conveyor assemblies 40A and 40B are hung in the toaster 10 using L-shaped slots or saddles 56 that are cut, stamped, machined or otherwise formed into the sides 41 of the conveyor assemblies 40A and 40B to receive the movable mounting pins 38. The width W of the conveyor assemblies 40A and 40B and the distance between the two end panels 37 and pins 38 allow the conveyor assemblies 40A and 40B to move freely between the end panels 37. The length of the mounting pins 38 that extend toward each other is such that the conveyor assemblies 40A and 40B can be mounted onto them and therefore into the toaster 10 without requiring tools or fasteners. The conveyor assemblies 40 can be removed simply by lifting the conveyor assemblies off the pins without tools or special fasteners and pulling the conveyor assemblies away from the platen 26 and out of the toaster 10. When the conveyor assemblies 40A and 40B are dropped into position, a gear 54 in each conveyor assembly 40A and 40B engages a mating drive gear 58 located at the bottom and in front of the end panel 37 on the left side housing 14 but not seen in
As the conveyor assembly 40A is moved further to the left of the figure, the mounting pin 38 eventually reaches the vertex or intersection of the horizontal section 78 and vertical section 76 of the L-shaped saddle 56. When the conveyor assembly 40A is at its left-most position, i.e., the intersection of the horizontal section 78 and vertical section 76 of the L-shaped saddle 56, the conveyor assembly 40A is lowered onto the mounting pins 38 such that the conveyor assembly 40A rests on the mounting pin 38 located at the top of the vertical section 76 of the L-shaped saddle 56. When the conveyor assembly 40A is resting on the mounting pins 38, the conveyor assembly 40A is effectively locked into the toaster by its own weight. The conveyor assembly 40A can be subsequently removed by lifting it upward and off the mounting pins 38 and pulling it laterally or horizontally away from the platen 26.
As stated above, the conveyor location control shafts 86 (shafts) in
The ends of the shafts 86 located in the plane of
The mounting pins 38 described above and which extend through the end panels 37 also extend into the end housings 14 and 16 and through mounting pin holes 84 formed into the actuator plates 82 inside both the left and right end housings 14 and 16. Stated another way, the mounting pins 38 that extend inward from the left housings 14 and toward the right end housing 16 and which the conveyor assemblies hang on also extend into the left and right housings and through mounting pin holes 84 formed in the actuator plates 82 located in each housing 14 and 16 for each pair of mounting pins 38.
The actuator plates 82 have horizontal elongated slots 87, the surfaces of which ride on bearings 89 fixed into the end plates 37 and that allow the actuator plates 82 to freely translate left and right responsive to rotation of the cam 90. In the preferred embodiment, each actuator plate 82 is provided with four elongated horizontal slots 87 to keep the actuator plates 82 vertical and to prevent them from becoming “cocked” or jammed. Alternate embodiments include the use of fewer than four slots 84 as well as more than four.
Rotation of the conveyor location control shafts 86 clockwise or counterclockwise rotates the cams 88 to various different positions where the lobes of the cams 90 cause the actuator plates 82 for each side of each conveyor assembly to move farther away from the platen 26 or closer to the platen 26. As the conveyor assemblies 40A and 40B are moved toward and away from the platen, tension in the drive chain 62 (not shown in
It should be noted that in
The drive motor 64 (and drive motor sprocket 66) pulls a drive chain 62, that runs over a first routing sprocket 69, a first conveyor drive sprocket 58A for the right side conveyor assembly 40A, a second routing sprocket 67, a second conveyor drive sprocket 58B for the left or second side conveyor assembly 40B and a single spring-loaded chain idler sprocket 68. Two idler sprockets can also be used. The first conveyor drive sprocket 58A and the second conveyor drive sprocket 58B are both chain driven as the figures depicts, but they are fixedly attached to rotating drive shafts (not shown) that extend through the end panels 37 and into the space between the left end housing 14 and right end housing 16 where the conveyor assemblies 40A and 40B are hung on the aforementioned mounting pins 38. The aforementioned drive gears 58 (one shown in
The sprocket 52 at a lower end 53A is attached to one end of a drive shaft (not shown) the opposite end of which is attached to the aforementioned drive gear 54 visible in the foreground of
Once the conveyor assembly is in place and resting on the mounting pins 38, horizontal translation of the mounting pins 38 relative to the platen 26 as described above determines the spacing or separation distance between the conveyor assembly 40 and the metal plates 42 that it comprised of. Lateral movement or translation of the pins 38 thus enables the separation distance between the conveyor 40 and the platen 26 to be adjusted even while the conveyor is in the housing and operating. Lateral movement of the mounting pins 38 can therefore affect the pressure exerted against the platen 26 by a food product on the conveyor and therefore determine the upward force exerted by the toaster drive motor on the conveyor assemblies.
Those of ordinary skill in the art will recognize that the mounting slots or saddles 56 enable the mounting assembly to be hung or rested on the mounting pins 38 and that the conveyor assemblies 40A and 40B will be weighted downwardly by their own mass. Those of ordinary skill in the art will also recognize that when the metal plates 42 attached to the wire links of the conveyor assemblies are urging a food product downwardly across the platen 26 that an equal an opposite upward force will be exerted on the conveyor assemblies 40A and 40B through the plates 42 and wire links. The upward force attributable to moving a food product downwardly across the platen should be kept below the weight of the conveyor assembly 40A and 40B in order to avoid having the conveyor assembly 40A and 40B lift itself off the mounting pins 38.
With regard to the conveyor assemblies 40A and 40B, it is important to note that the plates 42 are embodied as heat-absorbing and heat-conducting as well as heat-radiating material. Heat energy radiated from the platen 26 as infrared is absorbed by the plates 42, which causes their temperature to rise. Hot air between the platen 26 and the plates 42 also causes their temperature to rise. Since the metal plates 42 absorb heat through both radiation and conduction, they will transfer at least some of that heat energy into a food product or bread product that contacts the surfaces of the plates 42. The thin heat-absorbing, heat-conducting and heat-radiating plates thus act to absorb heat energy from the platen and transfer at least some of that energy into a food product that contacts the surfaces of the metal plates 42. Heat transmission from the metal plates 42 to a food product occurs primarily by conduction, however, heat in the plates 42 can also be transferred into the food products on the conveyor by convection as well as radiation. Heat that the plates 42 absorb from the platen that is conveyed to the food products is considered herein to be “imparted” to the food products whether the heat transfer mechanism is by radiation, conduction or convection..
In addition to imparting heat to the food products on the conveyor, the plates 42 also act to thermally insulate the exterior surfaces of the toaster 10 that face the platen 26 from becoming excessively hot. More particularly, the metal plates 42 intercept infrared energy emitted from the platen 26 and thus effectively insulate exterior surfaces of the toaster 10 from the heat-emitting platen 26 and help to keep exterior surfaces of the toaster cooler than they would be otherwise.
The description above is with respect to a single conveyor for brevity and clarity. The preferred embodiment of the toaster 10 however is a dual-conveyor assembly toaster. Both conveyor assemblies 40A and 40B depicted in
In a preferred embodiment, the metal plates 42 that comprise the conveyors 40A and 40B are provided with a predetermined surface roughness to facilitate the frictional engagement of a food product urged against the platen 26 after it is dropped into the space between the plates 42 and the platen 26. The roughness of the surface of the plates 42 is in one embodiment provided by shot peening the surfaces of the metal plates using a predetermined shot size. By selecting different shot sizes, the surface roughness can be changed to make the surface of the plates more or less irregular, increasing and decreasing the friction provided by the surface of the plates 42. In another embodiment surface roughness is provided by cold forming processes. In yet another embodiment, surface roughness is provided by abrading the plate surfaces with an appropriate abrasive medium.
As used herein, the term surface roughness is considered to be the arithmetic average deviation from the center line of the surface or as a RMS which is the route mean square of the deviations of the surface from the center line. Conveyor plate 42 surface roughness between 5 and 100 micrometers imbue the plates 42 with the ability to grab relatively smooth bread products and pull them across the hot surface of the platen 26 to prevent the food product from being stuck in place against the heated platen surface and burning without abrading the bread products' surfaces. In another embodiment, the plates 42 are provided with a surface “roughness” to frictionally engage a food product by a horizontal grain orientation.
As set forth above, the conveyor assemblies 40 are held in place and the gears engaged to each other solely by the weight of the conveyor assemblies themselves. Alternate embodiments include the use of one or more hold down springs and/or common barrel-bolt latches (not shown in the figures) to prevent the conveyor assemblies from being accidentally lifted out of position. Hold-down springs and/or barrel bolt latches will also reduce the likelihood that a conveyor assembly 40A or 40B might lift itself up and off the mounting pins 38 due to the reactive force created by the friction of a food product against the platen 26.
Finally,
In either embodiment of the toaster (10 or 10A), mounting pins and the slots that the pins rest in are considered to be a “mounting mechanism.” The pin and slots support the conveyor assemblies in such a way that the conveyor assemblies can be lifted in and out of the toaster without tools and the lateral spacing of the conveyor assemblies from the platen 26 can be adjusted by an operator, even while the conveyors inside the conveyor assemblies 40A and 40B rotates. In the preferred embodiment of the toaster 10 where the pins 38 are located at the toaster 10, the pins 38 are movable and the slots 56 are “fixed” in that they are formed into the sides 41 of the conveyor assemblies 40A and 40B. In a second embodiment of the toaster 10A where the slots 56A are in the toaster 10A, the pins 56A are “fixed” in that they extend from the sides 41 of the conveyor assemblies 40A and 40B. The mounting pins and slots are thus considered herein to be a re-positionable mounting mechanism, whether pins are on the toaster or on the conveyor assemblies and whether slots are on the conveyor assemblies or on the toaster. It should be noted too that one of the two conveyor assemblies 40A or 40B can be configured to have slots formed in one or both of the sides 41 and be supported in the toaster housing by adjustable pins that extend from opposing end panels 37 while the other conveyor assembly 40B or 40A can be configured to have mounting pins extend from one or both of its sides 41 and be supported in the toaster housing by corresponding adjustable slots formed into opposing ends.
While the pins shown in the figures are cylindrical and having circular cross sections, the mounting pins can have other shapes. A mounting pin can have cross sections that are square, triangular, elliptical or rectangular, all of which are considered herein to be equivalent to the round cross-sectioned pins shown in the figures. The height or length of the mounting pins is a design choice and will be determined somewhat by the desired spacing between the end panels 37 and the conveyor assemblies sides 41.
Those of ordinary skill in the art will appreciate that in either embodiment, the conveyor assemblies 40A and 40B can be individually removed from the toaster 10 simply by lifting them vertically upward and pulling them away from the platens without requiring any tools or disassembly. Once the conveyor assemblies are removed from the toaster, they can be immersed in cleaning solutions because there are no heating elements or electrical connections in the conveyor assemblies.
The foregoing description is for purposes of explanation and illustration only. The true scope of the invention is defined by the appurtenant claims.
