Patent Application
20080276777
Workpieces, including food products, are cut or otherwise separated into smaller portions by processors in accordance with customer needs. It is usually highly desirable to portion and/or trim the workpieces into uniform sizes, for example, for steaks to be served at restaurants or chicken fillets used in frozen dinners or in chicken burgers. Much of the portioning/trimming of workpieces, in particular food products, is now carried out with the use of high-speed portioning machines. These machines use various scanning techniques to ascertain the size and shape of the food product as it is advanced on a moving conveyor. This information is analyzed with the aid of a processing unit to determine how to most efficiently portion the food product into optimum sizes. For example, a customer may desire chicken breast portions in two different weight sizes, but with no fat or with a limited amount of acceptable fat. The chicken breast is scanned as it moves on a conveyor belt and a determination is made through the use of the processing unit as to how best to portion the chicken breast to the weights desired by the customer, thereby using the chicken breast in the most effective manner.
While some portioned workpieces, such as those described above, are packaged and sold in individual portions, others are packaged and sold as a single workpiece having a plurality of individual portions. For example, frozen goods, whether raw, pre-cooked, or pre-baked may be cut into individual slices prior to thawing, baking, microwaving, etc., and then packaged for sale to the consumer. The consumer thaws, bakes, microwaves, etc., and consumes the goods without having to cut them into individual portions. Although packaging portioned workpieces in this manner provides a certain convenience to the consumer, loosely packaged individual portions tend to move around inside the packaging, damaging the individual portions and creating a mess. In the case of goods having toppings, the toppings are often dislodged from loosely packaged individual slices, forcing the consumer to reassemble the individual portions prior to thawing, baking, microwaving, etc.
As a workpiece advances on a conveyor, portioning and/or trimming of the workpiece can be carried out by various cutting devices, including high-speed fluid jet cutters or rotary or reciprocating blades. In the case of a fluid jet cutter, a thin, high-speed jet of cutting fluid impinges the workpiece. The cutting fluid can be water or any other suitable cutting fluid. Pressurized cutting fluid is ejected from a small orifice to create the thin, high-speed jet, as is known in the art. When the cutting fluid impinges the workpiece, a thin slice of material is removed, preferably without any appreciable amount of cutting fluid being absorbed into the workpiece.
The flow of cutting fluid from a known fluid jet cutter is selectively controlled by a blocking pin disposed within the housing of the cutter. The blocking pin comprises a rod with a round cross-section and is selectively rotated between a first position and a second position. In the first position, one end of the blocking pin covers the orifice from which the fluid jet is emitted, thereby disrupting the flow of the cutting fluid. In the second position, the blocking pin does not cover the orifice and does not disrupt the flow of the cutting fluid.
Currently known blocking pins with round cross-sections have several advantages. First, when a blocking portion of the pin becomes worn, a round pin is easily rotated so that an unworn portion of the pin performs the blocking function. Further, because known blocking pins have round cross-sections, when a blocking pin is positioned in the path of the cutting fluid, most of the cutting fluid contacts the pin at an oblique angle, thereby reducing the amount of wear on the pin. In addition, blocking pins with a round cross-section are easily manufactured from round bar stock.
While the inclusion of a round cross-section provides several advantages, it also results in at least one disadvantage. Because the pin has a round cross-section, as the pin is initially rotated from the second position to the first position, the cutting fluid is deflected off of the surface of the pin so that it is emitted from the cutter at a downward angle. This initial downward spray causes imprecise and unsightly cuts and also causes additional cutting fluid to be absorbed by the workpiece.
A conveyor belt assembly used with a high-speed fluid jet cutter must not restrict the rapid removal of the cutting fluid from the conveying surface. One method of accomplishing this is to provide a conveyor belt assembly having a conveying surface formed from a lattice network of support members. The apertures defined by the support members of the lattice network allow spent cutting fluid to drain from the conveying surface, or to pass through the conveying surface, and into a spent cutting fluid receiver.
Although existing conveyor belt assemblies of a lattice type design are capable of conveying products for use in portioning machines utilizing fluid jets, they are not without problems. One problem relates to the undesirable inclusion of cutting fluid in the portioned workpiece. As the jet of cutting fluid passes through the workpiece, it impinges the conveyor belt and a portion of the cutting fluid splashes back onto the workpiece. The splashed cutting fluid can adhere to the surface of the workpiece, especially when the workpiece is frozen. The splashed cutting fluid can also be absorbed into the workpiece.
In addition to splashing cutting fluid directly back onto the workpiece, the cutting process also creates a fine mist of cutting fluid that remains suspended in the air for an extended period of time. This mist of cutting fluid eventually settles, some of it settling on a workpiece or on the conveyor belt, where it can contact the underside of a workpiece.
An apparatus for cutting a pattern in a workpiece to divide the workpiece into smaller portions is disclosed. The apparatus includes a conveyer for advancing the workpiece through a plurality of work areas, the conveyor comprising an endless conveyer belt supported by a support structure. The apparatus further includes a cutting unit comprising a drive mechanism located above the conveyer and selectively movable relative to the conveyor. One or more cutters are coupled to the drive mechanism, which selectively moves the cutters relative to the workpiece to cut a desired pattern in the workpiece. The pattern comprises a plurality of sequential cut and uncut sections, the plurality of cut and uncut sections defining a perforation in the workpiece. The uncut sections hold the portions of the workpiece together, while the cut sections allow a consumer to separate a portion from the workpiece by tearing, thus eliminating the need for a cutting implement.
In accordance with a further aspect of the disclosed apparatus, a scanning unit scans the workpiece to detect physical characteristics of the workpiece including, but not limited to, size, shape, weight, and the presence of discontinuities. The information detected by the scanner is used by a processing unit to determine the pattern to be cut in the workpiece.
In accordance with another aspect of the disclosed apparatus, the cutter is a fluid jet cutter that includes a housing and a blocking pin disposed therein. The blocking pin is selectively rotatable between a first position and a second position. When the blocking pin is in the first position, a first end of the blocking pin is disposed in the path of the flow of cutting fluid, thereby disrupting the flow of cutting fluid emitted from the fluid jet cutter. When the blocking pin is in the second position, the blocking pin does not disrupt the flow of cutting fluid emitted from the fluid jet cutter. The first end of the blocking pin includes one or more substantially flat surfaces, one of which is located so that the flow of cutting fluid impinges the surface at an approximately 90° angle when the blocking pin is in the first position. The inclusion of a flat surface on the blocking pin decreases the transition time required to disrupt or restore the flow of cutting fluid from the fluid jet cutter.
In another aspect of the disclosed apparatus, the conveyor comprises a belt formed from a plurality of connecting rods rotationally coupled to a plurality of pickets. The connecting rods and the pickets cooperate to define a conveying surface having a plurality of apertures extending therethrough. The apertures allow cutting fluid from a fluid jet cutter to pass through the belt to a location remote to the workpiece. The apertures of the belt are larger in areas of the belt that are more frequently impinged by the cutting fluid emitted from the fluid jet cutter. The presence of larger aperture reduces the total amount of splashback caused by cutting fluid impinging the belt. Reducing splashback in turn reduces the amount of cutting fluid that adheres to or is absorbed by the workpiece.
In a further aspect of the disclosed apparatus, an exhaust unit draws air from the work area. Particles of cutting fluid suspended in the air are removed from the work area along with the air and are disposed in a location remote to the work area.
In accordance with another aspect of the disclosed apparatus, an air knife is disposed above the belt and emits a high intensity sheet of air flow onto the belt. The air flow removes excess cutting fluid from the belt. The airflow also removes particles of the workpiece created during the portioning process from the belt.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
Referring to
A workpiece 100 is first carried by the conveyor 30 to a scanning unit 24 disposed above the belt. The scanning unit 24 scans the workpiece to ascertain selected physical parameters, such as length, width, size, area, circumference, thickness, volume, and shape. Weight can also be determined, typically by utilizing an assumed density for the workpiece. In addition, it is possible to locate selected features of the workpiece 100 that appear as discontinuities. For example, if the workpiece is a baked good with different toppings, the type, size, location, and number of various toppings can be determined.
The scanning can be carried out by a variety of techniques, including utilizing a video camera to view a workpiece illuminated by one or more light sources. Light from the light source extends across the moving conveyor belt 34 to define a sharp shadow or light stripe line, with the area forwardly of the transverse beam being dark. When no workpiece is being carried by the conveyor, the shadow line/light stripe forms a straight line across the conveyor belt. However, when a workpiece passes across the shadow line/light stripe, the upper, irregular surface of the workpiece produces an irregular shadow line/light stripe as viewed by a video camera directed downwardly on the workpiece and the shadow line/light stripe. The video camera detects the displacement of the shadow line/light stripe from the position it would occupy if no workpiece were present on the conveyor belt. This displacement represents the thickness of the workpiece along the shadow line/light stripe. The length of the workpiece is determined by the length of time that shadow lines are created by the workpiece. In this regard, an encoder is integrated into the conveyor 30, with the encoder generating pulses at fixed time intervals corresponding to the forward movement of the conveyor.
In lieu of a video camera, the scanning unit 24 may instead utilize an x-ray apparatus for determining the physical characteristics of the workpiece, including its shape, mass and weight. X-rays may be passed through the object in the direction of an x-ray detector. Such x-rays are attenuated by the workpiece in proportion to the mass thereof. The x-ray detector is capable of measuring the intensity the x-rays received thereby after passing through the workpiece. This information is utilized to determine the overall shape and size of the workpiece, as well as the mass thereof. An example of such an x-ray scanning device is disclosed by U.S. Pat. No. 5,585,603, incorporated by reference herein.
The data measured/gathered by the scanning unit 24 is transmitted to a processing unit 28, preferably on board the portioning apparatus 20, which records the location of the workpiece 100 on the conveyor 30, as well as the shape and other parameters of the workpiece. With this information, the processing unit 28 determines how to optimally cut or portion the workpiece.
The portioning may be carried out by various types of cutting/portioning devices including high-pressure water jets as disclosed in U.S. Pat. No. 5,927,320, which is incorporated by reference herein. Other types of cutting devices may be utilized, including band saws, reciprocating saws, circular saws, guillotine knives, and lasers.
Still referring to
It should be appreciated that the processing unit 28 may determine portioning patterns according to various other criteria without departing from the spirit of the present disclosure. According to one criterion, the processing unit 28 portions the workpiece according to a predetermined pattern, but virtually orients the pattern on the workpiece to minimize the intersection of the pattern with workpiece discontinuities. According to another criterion, the processing unit 28 optimizes the orientation of a predetermined pattern so that the number of workpiece discontinuities is substantially equal for each portion.
Referring to
Still referring to
The length of a cut section 106 is generally controlled to have a fixed relationship to an adjacent uncut portion. For example, for certain types of workpieces, a 5:1 ratio of cut section to uncut section provides the desired stability to hold the workpiece together, while allowing a consumer to separate a slice from the workpiece by tearing at the perforation. It should be understood that the desired ratio of cut section length to uncut section length will vary between different types of workpieces. The desired ratio may also vary within a single workpiece based on differences in the local thickness, density, or other characteristics of the workpiece 100. Optimal ratios can be determined by the processing unit 28 based on information received from the scanning unit 24. Such ratios can vary from at least 10:1 to 1:5.
A further aspect of the presently disclosed portioning apparatus 20 is a blocking pin 60 disposed within a fluid jet cutter 50, which enables the cutter 50 to start or stop the high speed flow of cutting fluid with increased precision. Referring to
Referring to
As shown in
As the blocking pin 60 moves from the second position to the first position, the cutting fluid enters the housing 52 and impinges the first surface 66 of the blocking pin 60. Because the cutting fluid enters the housing 52 in a direction lateral to the first surface 66, the substantially flat first surface 66 deflects the cutting fluid broadly. Further, the substantial flatness of the first surface 66 decreases the time required to transition from the second position, when the flow of cutting fluid is not disrupted, to the first position, when the blocking pin 60 completely disrupts the flow of the cutting fluid.
The high pressure flow of cutting fluid that impinges the first surface 66 of the blocking pin 60 causes wear on the first surface, eventually decreasing the effectiveness of the surface to act as a blocker. When the first surface 66 of the blocking pin 60 becomes worn, the blocking pin can be rotated so that the second, third, or fourth surface is impinged by the flow of cutting fluid. As each successive surface becomes worn, the blocking pin 60 can again be rotated so that an unworn surface is impinged by the flow of cutting fluid. By rotating the blocking pin 52 until all surfaces on the first end portion 62 of the blocking pin are worn, the useful life of the blocking pin is increased fourfold. Further, the second end portion 64 of the blocking pin 60 can be formed with a plurality of substantially flat surfaces similar to the first through fourth surfaces of the first end portion 62, When all four surfaces of the first end portion 62 are worn, the orientation of the blocking pin 60 within the housing 52 can be reversed so that the second end portion 64 of the blocking pin 60 selectively blocks the fluid outlet in the same manner as previously done by the first end portion 62 of the blocking pin 60.
Referring to
Each picket 38 has a length formed from a single strand of flat wire. The flat wire is repetitively bent to form links 39, where each link is an individual “wave” in the elongate wave-shape of the pickets 38. The pickets 38 are coupled to the left and right drive chains 42, 44 so that the length of the pickets 38 is perpendicular relative to the longitudinally oriented length of the drive chains 42, 44. The pickets 38 cooperate with the connecting rods 36 to define a plurality of apertures 46a and 46b extending through the conveying surface 35.
In another aspect of the presently disclosed portioning apparatus 20, the pickets 38 of the conveyer belt 34 are formed so that the apertures 46b in the belt 34 are larger in areas of the belt that are subjected to a greater volume of cutting fluid during a portioning operation. As shown in
When the portioning apparatus 20 portions a workpiece 100 in the manner shown in
As a fluid jet cutter 50 portions a workpiece 100, fine particles of cutting fluid are reflected off of the workpiece, the conveyor belt, and the bottom of the cutting fluid collection tank. These reflected particles are suspended in the air to form a mist around the conveyor belt. If the particles located above the conveyor belt are not removed from the work area, they can settle onto surfaces in the work area, including surfaces of workpieces 100 being portioned therein. In addition, because the airflow under the conveyor belt is turbulent, fluid particles suspended below the conveyor belt can be blown back up through the conveyer belt onto the workpieces 100.
Referring to
Standard exhaust units used in conjunction with fluid jet cutters normally result in an air velocity in the area of the conveyor belt of approximately 200 feet per minute. In contrast, the exhaust system of the presently disclosed portioning apparatus draws air from the area of the conveyor belt at a velocity of at least 250 feet per minute. In one preferred embodiment of the presently disclosed portioning apparatus 20, the exhaust unit draws air from the area of the conveyor belt at a velocity of approximately 400 feet per minute. Increasing the rate at which the exhaust unit draws air from the work unit improves workpiece quality by lowering the amount of cutting fluid particles in the work area that eventually settle on the workpieces 100. It should be appreciated that while the exhaust unit 70 of the disclosed embodiment is disposed under the conveyor 30, the exhaust unit 70 can be located in any position that allows the unit to draw air from the work area. Other suitable locations include, but are not limited to, above the belt of the portioning apparatus, in the ceiling of the workroom in which the portioning apparatus is located, or in a wall.
After the workpiece 100 has been portioned by the cutting unit 48, the conveyor 30 advances the portioned workpiece 100 to an area where the workpiece is removed from the belt 34 for packaging or further processing. Referring to
While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
