BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed generally to a loading machine and, more particularly, to a system and method for loading produce trays into a shipping container.
2. Description of the Related Art
Shipping containers for perishable products, such as apples, generally contain a series of stiff paper pulp trays with indentations where each indentation contains an individual piece of produce (e.g., an apple). With current technology, these produce trays are loaded and shipped down an assembly line where produce workers must manually remove each loaded produce tray from the assembly line and manually load it into a shipping container. The shipping containers typically contain a number of produce trays laid on top of each other.
This labor-intensive and back-breaking process may lead to produce damage if the tray is dropped while being manually inserting into the shipping container. In addition, if the trays are sloppily loaded into the shipping container, they may be dropped several inches thus causing damage to the produce. Therefore, it can be appreciated that there is a significant need for a system and method for automatically loading produce trays into a shipping container. The present invention provides this, and other advantages, as will be apparent from the following detailed description and accompanying figures.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
FIG. 1 is a perspective view of the input side of the tray loading machine described herein.
FIG. 2 is a perspective view of the output side of the machine of FIG. 1.
FIG. 3 illustrates the subassemblies of the machine of FIG. 1.
FIG. 4 is an exploded diagram of FIG. 3 showing the subassemblies of the machine of FIG. 1.
FIG. 5 is an enlarged view of the container positioning assembly of FIG. 4.
FIG. 6 is an enlarged view of the tray feed assembly of FIG. 4.
FIG. 7 is an enlarged view of the tray lift assembly of FIG. 4.
FIG. 8 is an enlarged view of the tray left assembly of FIG. 4 as viewed from the exit to the system of FIG. 1.
FIG. 9 is a view of the tray lift assembly of FIG. 7 with a box lift mechanism activated.
FIG. 10 is a view of the tray lift assembly of FIG. 8 with the lift rods activated.
FIG. 11 is a view of a standard shipping container modified for use with the loading system of FIG. 1.
FIG. 12 is a view of a European shipping container modified for use with the loading system of FIG. 1.
FIG. 13 is a view of a rigid plastic container (RPC) shipping container for use with the loading system of FIG. 1.
FIGS. 14A-14D illustrate a loading sequence of trays with the system of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
The present disclosure is directed to a machine and techniques for automatically loading trays of produce into shipping containers. The disclosure is embodied in a system 100, illustrated in FIG. 1. A frame assembly 102 may be constructed from extruded aluminum, steel, or any other suitable material to provide the necessary rigidity and structural support. A controller 104 contains switches, sensors, motor controllers, and air valves. The controller 104 also includes a programmable logic controller (PLC) to control the motors, air valves, and the like. The PLC (not shown) is a well known commercially available product manufactured by a number of different companies, such as Rockwell, National Instruments, Toshiba, and the like. The PLC receives inputs from switches and sensors and generates output signals to control the motors and air valves. One skilled in the art can readily program a PLC utilizing the description of the system and sequences of events described herein.
The system 100 includes a container feed assembly 110. A reference arrow 112 indicates direction of movement of a container 114 into the system 100. Although not illustrated in FIG. 1, a conventional conveyor belt delivers the empty containers 114 to the system 100 where trays of produce are automatically loaded into the container. The container feed assembly 110 comprises a container conveyor 116 driven by a container conveyor motor 118. As will be described in greater detail below, various sensors and other mechanisms are used to stop the container conveyor 116 when the container 114 is in the proper position for loading. The controller 104 includes a motor controller that turns the container conveyor motor 118 on and off.
The system 100 also includes a container positioning assembly 120. The container positioning assembly 120 comprises a left guide assembly 124 (see FIGS. 4-5) and a right guide assembly 126. Operational details of the container positioning assembly 120 and the operation of the left and right guide assemblies 124-126 will be provided below.
FIG. 2 is another perspective view of the system 100 and illustrates the container 114 as it exits from the system in the direction of movement 112. FIG. 2 provides a more detailed view of the conveyor container motor 118, which is mechanically coupled to the container conveyor 116 in a conventional manner and operates in a manner well known to those of ordinary skill in the art. Although not illustrated in FIG. 2, a conventional conveyor belt may abut the system 100 to receive and convey the loaded containers 114 as they exit the system 100.
Also illustrated in FIGS. 1-2 is a tray feed assembly 170. As will be discussed in greater detail below, loaded trays of produce are delivered to the tray feed assembly 170. A reference 172 illustrates a direction of movement of the loaded trays into the tray feed assembly 170. Operational details of the tray feed assembly 170 are provided below.
FIG. 3 is a perspective view of FIG. 1 with the frame assembly 102, controller 104, and container 114 removed to better illustrate the physical interrelationship of the container feed assembly 110, container positioning assembly 120, tray feed assembly 170 and a tray lift assembly 250. As will be described in detail below, the tray left assembly 250 includes a plurality of lift rods 252 that rise up through holes in the container 114 (see FIGS. 1-2) to a point just below the tray feed assembly 170. The loaded tray of produce is deposited on the lift rods 252, which are then lowered to thereby lower the loaded produce tray into the container 114.
FIG. 4 is an exploded view of FIG. 3 illustrates the individual components that comprise the container feed assembly 110, the container positioning assembly 120, the tray feed assembly 170, and the tray lift assembly 250. As will be described in greater detail below, an empty container 114 is delivered to the system 100 in the direction of movement 112 by the container feed assembly 110. As the container 114 moves into the system 100, the container positioning assembly 120 stops the container and positions it in a precise location for loading. The tray feed assembly 170 receives a fully loaded produce tray and delivers it into position over the open container 114. The tray lift assembly 250 operates to receive the loaded tray and to gently lower it into the open container 114. Subsequent trays are loaded on top as the tray lift assembly 250 retracts into the container 114. When the tray is fully loaded, the container positioning assembly 120 releases the loaded container 114 and the container feed assembly 110 activates to deliver the fully loaded container to the exit of the system 100. With an overall understanding of the operation of the system 100, the operational details of the various assemblies may now be explained in detail.
FIG. 5 illustrates the container positioning assembly 120. The container positioning assembly 120 comprises the left and right guide assemblies 124-126. The left guide assembly 124 is mounted to a left support member 128 which, in turn, is mounted to the frame assembly 102 (see FIG. 1). Similarly, the right guide assembly 126 is mounted to a right support member 130 which, in turn, is mounted to the frame assembly 102. The left and right guide assemblies 124-126 bend outwardly on the input side of the system 100 (see FIG. 1) to help guide the container 114 into position between the left and right guide assemblies. While the bent portion of the left and right guide assemblies 124-126 may passively guide the container 114 into position, the left and right guide assemblies of the system 100 also move back and forth in a direction of movement illustrated by the reference 132 to precisely position the container in a “load position” within the system 100. In addition, the left and right guide assemblies 124-126 effectively “squeeze” the container 114 and thereby retain it in the load position. Those skilled in the art will appreciate that the left and right guide assemblies 124-126 do not exert a force sufficient to damage the container 114, but merely to retain it in the proper load position within the system 100.
The left guide assembly 124 is moved back and forth in the direction of movement 132 by a left guide positioning assembly 134. Similarly, the right guide assembly 126 is moved back and forth in the direction of movement 132 by the right guide positioning assembly 136. The left guide positioning assembly 134 is mounted to the left support member 128 by a mounting bracket 144. Similarly, the right guide positioning assembly 136 is mounted to the right support member 130 by a mounting bracket 146.
Both the left and right guide positioning assemblies 134-136 utilize an air cylinder 138 that is fixedly mounted to a guide block 142. The pistons of the air cylinders 138 are mounted to the left and right guide assemblies 124-126, respectively. In addition, guide shafts 140 extend through the guide block 142 and also attach to the left and right guide assemblies 124-126. The guide shafts 140 provide torsional rigidity and structural support to hold the weight of the left and right guide assemblies 124-126 and components mounted thereon.
The air cylinder 138 is a commercially available product and has two air supply inlets. For the sake of clarity, the air supply inlets and air tubing is not illustrated herein. However, the operation of air cylinders is well known in the art and need not be explained in great detail. When air is supplied to one of the air inlets, the piston extends from the air cylinder 138. Conversely, when air is supplied to the other of the air inlets, the piston is forced back into the body of the air cylinder 138.
In operation, air is supplied to the first air inlet on the air cylinders 138 to extend the pistons and move the left and right guide assemblies 124-126 towards each other in the direction of movement 132 to thereby compress and retain the container 114 (see FIG. 1). When air is supplied to the second air inlet of the air cylinders 138, the pistons retract and the left and right guide assemblies 124-126 move away from each other in the direction of movement 132 to thereby release the container 114.
While both the left and right guide assemblies 124-126 may be moved towards each other to compress and retain the container 114 (see FIG. 1), those skilled in the art will appreciate that one of the guide assemblies (e.g., the right guide assembly 126) may remain in a fixed position while the remaining guide assembly (e.g., the left guide assembly 124) moves back and forth in the direction of movement 132. This accomplishes the same goal (i.e., positioning and retaining the container 114) while simplifying the overall process. The reverse process may also be implemented with the left guide assembly 124 remaining stationary with the right guide assembly 126 moving back and forth in the direction of movement 132 to position and retain the container 114 for loading and to retract and release the container after loading. Therefore, both left and right guide assemblies 124-126 may simultaneously operate to compress and retain the container 114 or, alternatively, one guide assembly may remain stationary while the other guide assembly moves back and forth in the direction 132 to retain or release the container. The system 100 is not limited by the specific operational details of the left and right guide assemblies 124-126.
The system 100 is advantageously designed to operate with a plurality of different shipping containers 114. Those skilled in the art will appreciate that a standard shipping container (see FIG. 11) is typically manufactured of cardboard. The cardboard shipping container 114 illustrated in FIG. 11 includes a bottom portion 240 and a lid portion 242. As illustrated in FIG. 11, the lid portion 242 includes a series of opposing flaps 244 that have not yet been sealed. The loaded containers 114 are conveyed to a different machine that closes and seals the flaps 244. The cut-away view of the bottom portion 240 of the container 114 illustrates that a number of holes 246 are placed in the bottom panel of the bottom portion 240. As will be discussed in detail below, the lift rods 252 of the tray lift assembly 250 rise up through the holes 246 in the bottom portion 240 of the container 114 to receive the loaded trays of produce from the tray feed assembly 170. In one embodiment, the standard cardboard shipping container 114 of FIG. 11 arrives at the input portion of the system 100 with the lid portion 242 already inserted over the bottom portion 240 of the container. Alternatively, the container 114 may contain only the bottom portion 240 of the container so that a lid portion 242 can be added after leaving the system 100. The lid may be added at a separate station. Examples of a lid selection technique are disclosed in U.S. Pat. No. 6,581,836, entitled “Apparatus and Method for Automatic Lid Selection in a Produce Packing Apparatus.”
Alternatively, the system 100 can accommodate European standard shipping containers, illustrated in FIG. 12. The European shipping container is similar to the standard cardboard shipping container of FIG. 11 in that it has a bottom portion 240 and a lid portion 242. As discussed above, the system 100 can accommodate loading of the European standard containers that arrive at the system 100 with lid portion 242 already in place or can load trays if only the bottom portion 240 is delivered to the system 100. In this embodiment, the lid portion 242 is installed over the bottom portion 240 at a separate station in the assembly line. The European standard shipping containers have different physical dimensions then the standard cardboard shipping container. As will be discussed in greater detail below, the system 100 can adjust the position and movement of several parts to accommodate containers 114 of different dimensions.
In yet another embodiment, containers 114 are manufactured from plastic and are reusable. The reusable plastic containers are sometimes referred to as a rigid plastic container (RPC), illustrated in FIG. 13. As seen in FIG. 13, the holes 246 in the RPC container 114 are rectangular. To accommodate the rectangular arrangement, the lift rods 252 are also rectangular and sized to fit through the rectangular holes 246 of the RPC container 114 illustrated in FIG. 13.
The holes 246 in the bottom portion 240 of the shipping container 114 in FIG. 11 and the holes (not shown) in the bottom portion 240 of the European shipping container 114 illustrated in FIG. 12 are circular in shape. Those skilled in the art will appreciate that the circular shape is merely for ease in manufacturing. The holes 246 in the bottom portion 240 can be rectangular and sized to accommodate the lift rods 252. Alternatively, the holes 246 in the bottom portion 240 can be in virtually any shape so long as they are positioned and sized to permit passage of the lift rods 252.
Those skilled in the art will also appreciate that there are fewer holes 246 in the bottom portion 240 of the containers 114 in FIGS. 11-12 than the number of holes in the RPC container of FIG. 13. It is not necessary that the bottom portion 240 of the cardboard shipping containers in FIGS. 11-12 have the same number of holes as the RPC. It is only necessary that the number and position of holes 246 in the bottom portion 240 of the containers 114 in FIGS. 11-12 correspond with the number of lift rods 252 that will come up through the bottom of the bottom portion 240 to receive the loaded trays, as will be described below. In turn, the number of lift rods 252 is not critical to satisfactory operation of the system 100. It is only required that a sufficient number of lift rods 252 be included to provide sufficient support for the multiple ones of the fully loaded trays. In the embodiment illustrated herein, there are a total of 36 lift rods 252. However, this number can vary and the system 100 can have more or less than 36 lift rods.
The dimensions of the cardboard shipping container and the RPC are different and the size of the trays that fit in the different sized containers is also different. Specifically, the standard cardboard shipping container is 12″×20″×12″ and typically contains five trays positioned on top of each other. Trays for the standard cardboard shipping container are 12″×19″ and have a number of indentations to accommodate individual pieces of produce, such as apples. The trays are traditionally manufactured from paper pulp and contained a series of indentations or pockets. However, the produce trays may be manufactured from recycled paper products, styrofoam, or any other suitable material. The system 100 is not limited by the type of material used to make the trays. The trays may be generically referred to herein as produce trays, fruit trays, or simply trays. Each pocket is designed to hold an individual piece of produce, such as an apple, peach, pear, or the like. The system 100 is not limited by the particular produce item contained in the trays or shipped in the containers 114. The trays are intended to “nest” inside each other within the container 114. To accommodate such nesting, the industry utilizes two different types of trays, commonly identified as an “A tray” and a “B tray.” The system 100 automatically loads an A tray first into the container 114 followed by a B tray. The system 100 alternates between an A tray and a B tray to provide the proper nesting within the container 114.
In contrast, the European standard container 114 and RPC is 24″×15.5″×8″ and is designed to accommodate approximately 2-3 trays. A tray configured for shipping in an RPC is 23″×15.″ although not critical to an understanding of the system 100, those skilled in the art will appreciate that each tray may be configured to hold a variable number of pieces of produce. For example, the standard shipping container can accommodate from 48 to 216 pieces of produce depending on the size of the produce with each 12″×19″ tray carrying a number of pieces of produce to accommodate the overall load. Similarly, the European RPC container 114 can accommodate from 18 to 49 pieces of produce distributed over multiple trays. As will be described in detail below, the system 100 detects the presence of a tray of produce and detects the type of tray (i.e., an A tray or a B tray) to assure that the proper tray type is inserted into the container 114.
To accommodate the three different types of containers 114, the system 100 includes a simple switch (not shown) in the controller 104 that is set to select either a standard shipping container, a European container, or an RPC. Generally speaking, the selection of container type occurs only once during a set up of a loading run and is not changed during the loading process. Similarly, the selection of trays to accommodate a selected number of pieces of produce occurs only during the set up of the loading run and is not changed during the loading process. For example, the selection of a standard shipping container and a standard tray accommodating 48 pieces of produce would occur only during the set up.
When the container selection switch is switched from one position to another, the air cylinders 138 adjust to different positions to accommodate the newly selected container type. Thus, the air cylinders 138 adjust initially to a width to accommodate the selected container type. During the loading operation, the air cylinders 138 operate in the manner discussed above to alternately position and retain the container 114 in the load position and to retract and release the container after loading has been completed.
In operation, the system 100 initially has no container 114. The empty container 114 is delivered to the system via a conventional conveyor (not shown) as previously discussed. The container feed assembly 110 receives the empty container 114 onto the container conveyor 116 (see FIG. 3), driven by the container conveyor motor 118. As the empty container 114 enters the system 100, it will encounter a stop 148 extending from both the left and right guide assemblies 124-126. The stops move back and forth in a direction of movement 149 from the left and right guide assemblies 124-126. As the empty container 114 arrives at the stop 148 it also interrupts a light beam from a photo sensor assembly 150 mounted on the left and right guide assemblies 124-126. Interruption of the photo sensor assembly 150 is detected by the PLC in the controller 104. In response, the controller 104 turns off the container conveyor motor 118 and thereby stop the container conveyor 116 with the empty container 114 in approximately the load position within the system 100. The photo sensor assembly 150 a light source and receiver to create a light beam that is interrupted by the container. Alternatively, the photo sensor assembly 150 may include a combined light source/receiver on either the left or right guide assembly 124-126 with a reflective element positioned on the other of the left and right guide assemblies. The operation of photo interrupter assemblies and reflective assemblies are known in the art and need not be described in great detail herein.
The interruption of the light from the photo sensor assembly 150 also triggers other activities within the system 100. Within the container positioning assembly 120, air cylinder 138 for the left guide assembly 124 and/or the air cylinder 138 for the right guide assembly 126 are activated to extend the guide assemblies toward each other in the direction of movement 132 perpendicular to the direction of movement 112 to thereby position the container 114. This action further positions the container 114 accurately within the system 100.
The interruption of the light from the photo sensor assembly 150 also triggers additional air valves in the controller 104 (see FIG. 2) to activate retainer air cylinders 152 mounted to the left and right guide assemblies 124-126 respectively. The retainer air cylinders 152 are fixedly mounted by brackets to the respective guide assemblies 124-126. A tang or flange 154 is mounted to the piston of the retainer air cylinder 152. Unlike the air cylinders 138, which have two air supplies and move only in two directions (i.e., back and forth in the direction of movement 132), the air cylinders 152 have four air supply inputs and include both a rotational direction of movement 156 and a linear direction of movement 158. When the light beam from the photo sensor assembly 150 is broken by the container 114, the controller 104 activates air valves to rotate the tangs 154 in the direction of movement 156 outwardly from the left and right guide assemblies 124-126, respectively. In operation, the tangs 154 are now located behind the container 115 (see FIG. 1). Following the rotational movement, or in conjunction therewith, another air valve in the controller 104 is activated to cause the air cylinders 152 to have linear movement in the direction of movement 158 toward the stops 148, thereby compressing the container 114 between the stops 148 and the tangs 154. Thus, the container 114 is held precisely in the load position by the stops 148, the tangs 154, and the left and right guide assemblies 124-126. As will be described in detail below, the precise location of the container 114 in the load position aligns the holes 246 (see FIG. 11) in alignment with the lift rods 252.
As discussed above, the system 100 can accommodate standard cardboard shipping containers (see FIG. 11) as well as a European container or an RPC. Because the standard cardboard shipping container has different dimensions from the RPC, the container positioning assembly 120 includes two different sets of stops 148 and two different sets of photo sensor assemblies 150 to accommodate the different size containers. Depending on the position of the container selection switch (not shown) in the controller 104 to select the shipping container type, only one set of photo sensor assemblies 150 is used to detect the position of the container 114 at the stop 148. In addition, only one set of stops 148 within the left and right guide assemblies 124-126, respectively, are activated. In FIG. 5, the set of stops 148 are activated for the standard shipping container. If the larger European container or the RPC were used with the system 100, the second set of stops 148 would be activated.
In addition, if the container 114 is a standard cardboard shipping container or a European container, the system 100 includes a detainer 160 that extends from the left guide assembly 124 and/or the right guide assembly 126. The detainer 160 contains a sharp edge to penetrate only the lid portion 242 of the cardboard shipping container 114 (see FIG. 11). The detainer 160 serves to hold the lid portion 242 in position while the bottom portion 240 of the container 114 is raised to receive the trays of produce, as will be discussed in greater detail below. As discussed above, in one embodiment, the container 114 includes both the bottom portion 240 and the lid portion 242 already inserted in place. In this embodiment, the detainer 160 operates in the manner described above. Alternatively, if only the bottom portion 240 of the container 114 is delivered to the system 100 (i.e., the lid portion 242 is placed on top of the bottom portion 240 at a separate machine station), the PLC in the controller 104 de-activates the air cylinder associated with the detainer 160 such that the detainer is not active. Furthermore, the detainer 160 is de-activated if the container 114 is an RPC.
The system 100 also includes the tray feed assembly 170 to receive loaded trays of produce. Operational details of the tray feed assembly 170 are illustrated in FIG. 6. The tray feed assembly 170 comprises a tray conveyor belt 174 and the movement of loaded trays into the tray feed assembly is in the direction of movement illustrated by the reference 172. Those skilled in the art will appreciate that a conventional conveyor belt (not shown) provides the loaded trays onto the tray conveyor belt 174. The tray conveyor belt 174 is operated by a tray conveyor motor 176. The tray conveyor motor 176 is coupled to the tray conveyor belt 174 by a conventional drive chain and sprockets. The PLC in the controller 104 controls the tray conveyor motor 176 in a manner described below. The operation of the tray conveyor belt 174 and tray conveyor motor 176 is known in the art and need not be described in greater detail herein.
The tray conveyor belt 174 delivers the loaded tray onto a tray cart 178. The tray cart 178 has four wheels 180 that move back and forth in grooves 182 (see FIG. 1) on the top of the frame assembly 102. The tray cart 178 is driven by a tray position air cylinder 184 that moves back and forth in a direction of movement indicated by the reference 190. The tray position cylinder 184 is a long-throw conventional air cylinder with two air connections to extend or retract a piston in the direction of movement 190. The tray position cylinder 184 is fixedly mounted to a tray position support member 186 which is mounted to the frame assembly 102 (see FIG. 1). In turn, the piston of the tray position cylinder 184 is mounted to a tray cart flange 188 which extends vertically at one end of the tray cart 178. As the piston of the tray position cylinder 184 extends, the tray cart flange 188 and the tray cart 178 move in the direction of movement 190 away from the tray position cylinder support member 186. If air is supplied to the other air connection on the tray position cylinder 184, the piston retracts thereby drawing the tray cart toward the tray conveyor belt 174. In operation, the tray position cylinder 184 is in a retracted position so that the tray cart 178 is located approximate the tray conveyor belt 174. As the tray conveyor belt 174 rotates, a loaded tray of produce is delivered onto the tray conveyor belt and delivered onto a spatula portion 192 of the tray cart 178. The spatula 192 is a large flat portion sized to receive and transport a loaded tray. Once the loaded tray of produce has been delivered onto the spatula 192, the air cylinder 184 is activated to push the tray cart 178 in the direction of movement 190 away from the tray conveyor belt 174.
As illustrated in FIG. 6, the tray cart 178 has a sidewall 193. Apertures 194 and 196 in the side wall 193 permit the detection of the loaded tray on the spatula 192 and the detection of the tray type (i.e., an A tray or a B tray). The aperture 194 permits passage of light from a photo sensor assembly (not shown) mounted on the frame assembly 102. Matching apertures 194-196 are on the opposite side wall 193, as illustrated in FIG. 3. Different photo sensor implementations are possible with the system 100. In one embodiment, the tray lift assembly 170 utilizes a photo emitter through one aperture 194 and a photo receiver in the corresponding aperture 194. When the loaded tray is moved from the tray conveyor belt 174 on to the spatula 192, the end of the tray interrupts the light beam passing through the apertures 194 thereby indicating to the PLC in the controller 104 that the loaded tray is in position on the tray lift assembly 170. The interruption of the photo beam through the apertures 194 causes the PLC to turn off the tray conveyor motor 176 to prevent additional trays from jamming the tray lift assembly 170. Alternatively, the tray lift assembly 174 may use a photo assembly that has a combined photo emitter and detector. In this embodiment, the photo emitter portion of the photo sensor emits a light that passes through the aperture 194 on one side of the tray cart 178. A reflective material is mounted on the opposite side of the tray cart 178 in alignment with the aperture 194 on that side of the tray cart. The light from the photo emitter portion of the photo assembly reflects off the reflective material such that the light beam from the photo emitter portion is reflected back to the photo detector portion of the photo sensor assembly. In either embodiment, a light beam is projected through the apertures 194 and is interrupted by the arrival of a tray into position on the spatula 192.
A proximity photo sensor assembly (not shown) is also mounted on the frame assembly 102 in alignment with the apertures 196. The photo proximity detectors are used to determine the tray type present on the spatula 192. Those skilled in the art will appreciate that an A tray contains pockets in the extreme corners of the tray. In contrast, a B type tray contains no pocket in that location and thus will not have any product in that location. When a loaded A tray is delivered onto the spatula 192, the proximity photo sensor aligned with the aperture 196 will detect the presence of produce in the corner locations and generate a signal to indicate that loaded tray is an A tray. On the other hand, if a B tray is delivered on to the spatula 192 no produce will be present in that location and the proximity photo sensors will generate a signal indicating the presence of a B tray. In this manner, the system 100 can test to make sure that the proper tray types are delivered to the container 114. It is a customary practice in industry that the first tray loaded into the container 114 is an A tray. This is followed by alternating B trays and A trays until the container is fully loaded.
When the first tray for a container 114 is delivered to the tray lift assembly 170, the photo sensor assembly aligned with the apertures 194 detect the presence of the loaded tray on the spatula 192 and turn off the tray conveyor motor 176. The photo sensor assembly aligned with the apertures 196 determines the tray type in the manner described above. If the tray type is correct (i.e., an A tray for the first tray in the container), the PLC activates the tray position cylinder 184 to push the tray cart 178 away from the tray conveyor belt 174. If the proximity photo sensor aligned with the aperture 196 detects an incorrect tray (i.e., an A tray when a B tray is expected or vice versa) the tray position cylinder 184 will not be activated. Instead, the PLC in the controller 104 (see FIG. 1) may shut down the entire system 100 to prevent the loading of incorrect trays into the containers 114. When the incorrect tray is removed, the system 100 may be restarted and the loading process continues.
As the tray cart 178 moves away from the tray conveyor belt 174, the loaded tray encounters a back stop assembly 200. The back stop assembly 200 includes a vertical back stop plate 202. The bottom of the back stop plate 202 is positioned just above the spatula 192. The spatula 192 is sized to fit under the back stop plate 202. However, the loaded tray of produce cannot fit under the back stop plate 202 and essentially slides off of the spatula 192 as the spatula slides underneath the back stop plate. With the spatula 192 fully withdrawn, the loaded tray of produce drops down into the open container 114 positioned below the tray feed assembly 170. The loaded tray is not dropped directly into the container 114, but is gently placed onto the tray lift assembly 250 in a manner that will be described in greater detail below. Thus, the tray feed assembly 170 receives a loaded tray of produce and gently deposits it on to the tray lift assembly 250.
A light curtain assembly 206 (see FIGS. 1, 3, and 4) is mounted to the frame assembly 102 in a position just below the tray feed assembly 170. The light curtain assembly 206 is essentially a series of photo emitters and photo detectors that form a “curtain” beneath the tray feed assembly 170. As a tray of produce is loaded onto the tray lift assembly 250, the tray interrupts at least a portion of the beams of light in the light curtain assembly 206. As the tray lift assembly 250 is lowered so that the loaded tray of produce is now within the container 114, nothing is in a position to block the light curtain formed by the light curtain assembly 206. The clear light pathway in the light curtain assembly 206 indicates that the produce tray is loaded into the container 114 and that the tray feed assembly 170 may load the next subsequent tray of produce. In response to the clear signal from the light curtain assembly 206, PLC in the controller 104 activates the tray conveyor motor 176 and activates an air valve so that the tray position cylinder 184 retracts and the tray cart 178 moves in the direction of movement 190 toward the tray conveyor belt 174 to receive the next loaded tray of produce. The process is repeated until the correct number of loaded trays of produce have been delivered into the container 114.
As noted above, the system 100 is capable of operation with standard cardboard shipping containers, as well as the European standard container and RPC. To accommodate the varying size of shipping trays, the tray feed assembly 170 has adjustments that are controlled by the container selection switch (not shown) in the controller 104. The backstop assembly 200 is adjusted to accommodate the larger trays and the larger size of the container 114. An air cylinder 208 is fixedly mounted to a guide block 212. The guide block 212 is mounted on a mounting flange 216 of bracket 218. The bracket 218 is coupled to the frame assembly 102 (see FIG. 1). Two guide shafts 210 extend through the guide block 212 and are coupled to the back stop plate 202. The guide shafts 210 provide torsional rigidity and support for the backstop plate 202. The piston (not shown) of the air cylinder 208 is also mounted to the back stop plate 202. Depending on the position of the container selection switch, the air cylinder 208 is activated for movement in a direction of movement 214 to move the back stop plate 202 closer to the tray conveyor belt 174 if the container 114 is the standard shipping container or further from the tray conveyor belt if the container 114 is an RPC.
The tray feed assembly 170 also includes tray guides 220 that bend outwardly in the region approximate the tray conveyor belt 174 to guide the loaded trays off of the tray conveyor belt and on to the spatula 192. To accommodate trays for different container types (i.e., the standard shipping container, the European container, and the RPC), the separation between the tray guides 220 is adjustable. FIG. 6 illustrates a pair of tray guide adjustment cylinders 222. The tray guide adjustment cylinders 222 are fixedly mounted to cylinder brackets 224. In turn, the cylinder brackets 224 are mounted to a tray cart support member 226, which is part of the tray cart 178. Pistons 228 extending from the tray guide adjustment cylinders 222 are mounted to sliding blocks 230. The sliding blocks 230 slide within block supporting brackets 232 that are also mounted to the tray cart support member 226. Depending on the position of the container selection switch (not shown) in the controller 104, the pistons 228 of the tray guide adjustment cylinders 222 extend or retract. As the pistons 228 move, the sliding blocks 230 move within the block support brackets 232. The sliding blocks 230 are mounted to vertical brackets 234 which are coupled to the respective tray guides 220. The tray guides 220 are fully supported by the sliding blocks 230 and the vertical brackets 234. Upon activation of the container selection switch, the tray guide adjustment cylinders 222 are activated and the pistons move back and forth in a direction of movement 236 to accommodate the width of the trays corresponding to the selected container type.
The back stop plate 202 and the tray guides 220 of the tray feed assembly 170 position the loaded tray directly above the container 114 (see FIG. 1). As the spatula 192 is pulled out from underneath the tray, the tray would normally drop into the container 114. However, dropping the loaded tray into the container 114 may damage the produce. To prevent such damage, the system 100 includes the tray lift assembly 250 to receive and gently lower the loaded trays into the container 114. The tray lift assembly is illustrated in FIGS. 7-10. In FIG. 7, it can be seen that the tray lift assembly 250 comprises a plurality of lift rods 252 mounted on a rod mounting plate 254. The lift rods 252 are metal and can be manufactured in any convenient shape. In the present system 100, the lift rods are rectangular in shape and sized to fit easily through the holes in the European standard RPC. The placement of the lift rods 252 is also based on the spacing and position of holes in the RPC. Standard cardboard containers have been modified so that the bottom portion 240 of the container 114 includes a series of holes 246 (see FIG. 11) to correspond with the lift rods 252 in number, size, and location.
The lift rods 252 are fixedly attached at one end to the rod mounting plate 254. The opposite or free end of the lift rods 252 are inserted through a guide plate 256 to guide the lift rods in their upward movement and to provide structural support for the lift rods. The guide plate 256 is mounted to the frame assembly 102 (see FIG. 1) by a frame attachment flange 258. The guide plate 256 is further attached to the frame assembly at other locations as well to provide strength and rigidity. The guide plate 256 contains a series of apertures 260 in positions corresponding to each of the lift rods 252. The apertures 260 allow the lift rods 252 to pass through as the rod mounting plate 254 rises up during the tray loading process. This will be explained in greater detail below.
In one embodiment, all lift rods 252 are equal in length. In an alternative embodiment, illustrated in FIGS. 7-8, the lift rods 252 in a peripheral portion 262 of the guide plate 256 are greater in length than lift rods in a central portion 264 of the guide plate 256. In operation, the longer lift rods 252 in the peripheral portion 262 and shorter lift rods in the central portion 264 of the guide plate 256 cause the tray to sag slightly in the center as the spatula 192 (see FIG. 6) is retracted beneath the back stop plate 202. The slightly sagging tray is more easily inserted into the container 114. However, the system 100 will operate satisfactorily with all lift rods having an equal length.
In yet another alternative embodiment, the lift rods 252 may be longer only at the region near the input to the system 100 and the exit of the system. This will cause the loaded tray to sag in only one dimension.
The process of positioning the container precisely at the load position in the system 100 has already been discussed in detail above with respect to the container positioning assembly 120 (see FIG. 5). Proper positioning of the container 114 brings the holes 246 (see FIG. 11) in the container into alignment with the lift rods 252. During the loading operation, the rod mounting plate 254 rises so that the lift rods 252 come up through the holes 246 in the bottom of the container 114 to a position just below the tray feed assembly 170.
The rod mounting plate 254 is slideably coupled to a lift support assembly 270. As best seen in FIG. 7, vertical guide shafts 272 are fixedly mounted to the lift support assembly 270. The vertical guide shafts 272 have a cylindrical cross section and may be solid guide shafts or tubes. Shaft support members 274 are positioned at the top and bottom of each vertical guide shaft 272 and are bolted, or otherwise fastened, to the lift support assembly 270. FIG. 8 is an exploded view of the tray lift assembly with the lift support assembly moved to illustrate guide flanges 276 that are positioned on each side of the rod mounting plate 254 to couple the rod mounting plate to the vertical guide shafts 272. The guide flanges 276 are sized to fit around the vertical guide shafts 272 and slide freely on the vertical guide shafts.
A tray lift motor 280 and gear box 282 provide the operational power for the tray lift assembly 250. As best seen in FIG. 8, the gear box 282 includes an output sprocket 284, which is coupled to a drive sprocket 286 by a drive chain 288. The drive sprocket 286 is coupled to a driveshaft 290 to transfer power to a lift sprocket 292. The lift sprocket 292 is rotatably coupled to the lift support assembly 270. A lift chain 294 is coupled to the lift support assembly 270 and wraps around a pulley 296 and the lift sprocket 292. As the tray lift motor 280 rotates, the lift chain rotates on the lift sprocket 292 and pulley 296 to cause the rod mounting plate to move up or down depending on the rotational direction of the tray lift motor.
The drive shaft 290 is also coupled to a transfer sprocket 298 by a transfer chain 300. The transfer sprocket 298 and transfer chain 300 are part of a mechanism to transfer power to the lift sprocket 292, lift chain 294, and pulley 296 on the opposite side of the lift support assembly 270. The transfer sprocket 298 is mounted to a transfer driveshaft 302 for rotation therewith. The transfer driveshaft 302 is supported in the middle by a center support bearing 302. At its far end, the transfer driveshaft 302 is coupled to a corresponding transfer sprocket 298 and transfer chain 300 on the opposite side of the lift support assembly 270. Thus, the lift support assembly 270 includes a lift chain 294 on each side of the rod mounting plate 154 to assure smooth movement of the rod mounting plate.
In another aspect of the system 100, it has been determined that the loading time for a standard shipping container can be reduced if the bottom portion 240 (see FIG. 11) of the container 114 is raised during the tray loading process. Similarly, the bottom portion 240 of the European container (see FIG. 12) and the RPC (see FIG. 13) may also be loaded more quickly if they are raised during the tray loading process. In this manner, the individual trays can be loaded more quickly into the container 114. In an exemplary embodiment, the bottom portion 240 of the container 114 is raised so that it is even with the top portion of the flaps 244. That is, the top of the bottom portion 240 is at approximately height as the top of the flaps 244. To accomplish this task, the system 100 includes a box lift platform 310, shown in its raised position in FIG. 9. The box lift platform 310 is raised and lowered by a box lift cylinder 312. In an exemplary embodiment, the box lift cylinder 312 is an air cylinder controlled by air valves in the controller 104 (see FIG. 1). The box lift cylinder 312 is fixably coupled to a box lift guide block 316. Box lift guide shafts 318 extend through the box lift guide block 316 and are coupled to the underside of the box lift platform 310. A piston 314 of the box lift cylinder 312 also attaches to the box lift platform 310.
When the standard shipping container 114 is in the load position within the system 100, the PLC in the controller 104 activates the box lift cylinder 312 to raise the box lift platform 310, as illustrated in FIG. 9. As previously discussed, detainers 160 (see FIG. 5) extend from the left guide assembly 124 and/or the right guide assembly 126 to retain the lid portion 242 of the standard shipping container while the bottom portion 240 is raised by the box lift platform 310.
Following the raising of the box lift platform 310, or in conjunction therewith, the tray lift motor 280 is activated in a rotational direction to raise the rod mounting plate 254 and lift rods 252 to rise up to receive loaded trays of produce from the tray feed assembly 170 (see FIG. 6).
In operation, the lift rods 252 are brought into position just below the spatula 192 (see FIG. 6). FIG. 10 illustrates the tray assembly 250 with the rod mounting plate 254 raised to the maximum height to receive the first loaded tray from the tray feed assembly 170 (see FIG. 6). FIG. 10 also illustrates the box lift platform 310 in its fully raised position. As can be seen in FIG. 10, at least a plurality of the lift rods 252 extend through the bottom of the container 114 (see e.g., FIG. 11) to a position just below the tray feed assembly 170. As the spatula 192 retracts in the manner described above, a loaded tray of produce is deposited onto the lift rods 252. The PLC in the controller 104 activates the tray lift motor 280 in a direction to lower the rod mounting plate 254. In this manner, the lift rods 252 are retracted slightly so that the first tray of produce is now within the container 114. As described above with respect to the tray feed assembly 170, a new loaded tray of produce (i.e., a B tray) is loaded onto the spatula 192. As the spatula 192 withdraws, the second tray of produce is deposited onto the top of the first tray of produce. The PLC in the controller 104 activates the tray lift motor 280 to further lower the rod mounting plate 254 so that the second tray of produce is now within the container.
As described above, the light curtain assembly 206 detects the presence of a tray of produce just below the tray feed assembly 170. As the rod mounting plate 154 is lowered, the tray of produce no longer interrupts the light beams of the light curtain assembly 206. This triggers the PLC in the controller 104 to stop the tray lift motor 280. Thus, the tray lift assembly 250 is in a position to receive the next loaded tray of produce.
This process continues until all trays of produce have been loaded into the container 114. When the final tray of produce has been loaded into the container, the PLC in the controller 104 activates the tray lift motor 280 to completely lower the rod mounting plate 254 such that the lift rods 252 are completely disengaged from the container 114. The PLC also activates air valves to retract the piston 314 of the box lift cylinder 312 to thereby lower the box lift platform 310. When the box lift platform 310 is in its resting position, the bottom portion 240 of the container 114 is now resting on the container conveyor 116.
The PLC in the controller 104 activates the air cylinders associated with the detainers 160 to withdraw the detainers from the lid portion 242 of the container 114. In conjunction therewith, the air valves are also activated to withdraw the stops 148 in the direction of movement 149 so that the pathway for the loaded container 114 is clear. In addition, the retainer air cylinder 152 is also activated in the linear direction of movement 148 to release the container 114. The retainer air cylinder 152 is also activated in the rotational direction of movement 156 to withdraw the tang 154 from the container pathway. In addition, the left guide assembly 124 and/or the right guide assembly 126 are also retracted so that the loaded container 114 may freely exit the system 100.
Following the release of the container in the manner described above, the container feed assembly 110 is activated such that the container conveyor 116 conveys the loaded container 114 in the direction of movement 112 to exit the system.
Operation of the system 100 to load the European container 114 (see FIG. 12) is essentially identical to that described above for the container of FIG. 11. If the container 114 includes both the bottom portion 240 and the lid portion 242, the detainer 160 (see FIG. 5) is activated to retain the lid portion 242 in position as the box lift platform 310 is activated to raise the bottom portion 240 into position below the tray feed assembly 170. As noted above, the dimensions of the European container of FIG. 12 are different from the dimensions of the standard shipping container illustrated in FIG. 11. In one embodiment, the PLC in the controller 104 activates the box lift cylinder 312 (see FIG. 9) to raise the box lift platform to a first predetermined position for the standard shipping container of FIG. 11 and raises the box lift platform 310 to a second different position if the container is the standard European container of FIG. 12. Alternatively, for ease in operation, the box lift cylinder 312 may be activated to raise the box lift platform 310 to a fixed position irrespective of the type of shipping container.
FIGS. 14A-14D illustrate the sequential action of certain components of the system 100 to load trays 320 into the container 114. For the sake of clarity, the simplified diagrammatic drawings of FIGS. 14A-14D generally illustrate the operation of certain elements of the system 100 to load multiple trays 320. In FIG. 14A, the rod mounting plate 254 of the tray lift assembly 250 has been activated to raise the lift rods 252 through the holes 246 in the bottom portion 240 of the container 114. The lift rods 252 are positioned just below the spatula 192 of the tray cart 178. Following activation of the rod mounting plate 254, or in conjunction therewith, the box lift cylinder 312 is also activated to raise the box lift platform 310. With the standard shipping container 114 of FIG. 11, the box lift platform 310 positions the bottom portion 240 so that the top edge of the bottom portion is roughly aligned with the top edge of the flaps 244 (see FIG. 11).
FIG. 14A also illustrates that the tray 320a (i.e., an A tray) of produce has been loaded onto the spatula 192 in the manner described above with respect to FIG. 6. When the tray 320a is in position, the PLC in the controller 104 activates the tray position cylinder 184 (see FIG. 6) to move the tray cart 178 in the direction of movement 190 away from the tray conveyor belt 174.
When the tray cart 178 has moved away from the tray conveyor belt 174, the spatula 192 moves beneath the backstop 202, as illustrated in FIG. 14B. The backstop 202 prevents the tray 320a from moving with the tray cart 178 and thereby removes the tray 320a from the spatula 192. At this point, the tray 320a is fully supported by the lift rods 252. It should be noted that the backstop 202 is positioned substantially in alignment with one edge of the container 114 so that the tray 320 is properly aligned for insertion into the container. As discussed above, the air cylinder 208 adjusts the position of the backstop 202 when the container selection switch (not shown) in the controller 104 selects a different container type. Thus, the backstop 202 maintains alignment with an edge of the container 114 to assure proper insertion of the trays 320.
With the tray 320a supported on the lift rods 252, the PLC in the controller 104 activates the tray lift motor 280 (see FIG. 9) in a direction to lower the rod mounting plate 254 such that the tray 320a on top of the lift rods 252 is lowered into the container 114, as illustrated in FIG. 14C. In one embodiment, the loaded tray 320a may be lowered to be completely within the container 114. However, as illustrated in FIG. 14C, the rod mounting plate 254 is lowered just enough that the loaded tray 320a is below the position of the light curtain assembly 206 (see FIG. 3). When the tray 320a no longer interrupts the light beams from the light curtain assembly 206, the tray is below the level of the tray cart 178 of the tray feed assembly 170. The clear signal from the light curtain assembly 206 triggers the PLC in the controller 104 to activate the tray position cylinder 184 (see FIG. 6) in the direction of movement 190 toward the tray conveyor belt 174, as illustrated in FIG. 14D. FIG. 14D also illustrates that a tray 320b (i.e., B tray) has been delivered to the spatula 190 via the tray conveyor belt 174 in the manner described above with respect to FIG. 6. As noted, the system 100 will typically alternate between an A tray and a B tray as designated by the trays 320a and 320b, respectively. This process continues with the rod mounting plate 254 being incrementally lowered as each successive tray 320 is delivered into the container 114. When the container 114 is fully loaded, the PLC in the controller 104 activates the tray lift motor 280 in a direction to completely lower the rod mounting plate 254 and thereby extract the lift rods 252 from the container 114. Following the extraction of the lift rods 252 from the container 114, or in conjunction therewith, the PLC in the controller 104 also activates the box lift cylinder 312 to thereby lower the box lift platform 310. Once the box lift platform 310 is in its resting position, the various mechanisms described above will release the fully loaded container 114. That is, the detainer 160 (see FIG. 5) is extracted from the lid portion 240 if the container 114 is delivered to the system with the lid in place. In addition, the air valves are activated to withdraw the stops 148 in the direction of movement 149 so that the pathway for the loaded container 114 is clear. The PLC in the controller 104 also activates the retainer air cylinder 152 in the linear direction of movement 148 to release the container 114 and to activate the retainer air cylinder in the rotational direction of movement 156 to withdraw the tang 154 from the container pathway. Finally, the left guide assembly 124 and/or the right guide assembly 126 may also be retracted so that the loaded container 114 may exit the system 100.
The container loading process from an RPC is similar in most respects to that described above. However, with an RPC, the detainer 160 (see FIG. 5) is not activated. In one embodiment, the box lift platform 310 is also inactive during the loading of an RPC. Alternatively, the box lift platform may be activated in the manner described above. Furthermore, the tray lift motor 280 and rod mounting plate 254 are activated in the manner described above such that the lift rods 252 extend through corresponding holes in the bottom of the RPC container 114 (see FIG. 13) to a point just below the tray feed assembly 170. The first loaded tray of produce is delivered by the tray feed assembly 170 onto the lift rods 252 in the manner described above. The tray lift motor 280 is activated in the reverse direction by the PLC in the controller 104 to lower the rod mounting plate 254 until the first tray of produce has cleared the light curtain assembly 206. At that point, the tray lift assembly delivers the next loaded tray of produce onto the top of the first tray of produce. This process continues until the RPC is completely loaded. At that point, the PLC activates the tray lift motor 280 to completely lower the rod mounting plate 254 to thereby disengage the lift rods 252 from the RPC 114. The stops 148 (see FIG. 5) and tangs 154 are withdrawn as described above. The left guide assembly 124 and/or right guide assembly 126 are also retracted to completely free the RPC 114. The container conveyor motor 118 is activated to deliver the fully loaded RPC 114 on the container conveyor 116 to the exit of the system 100.
Thus, the system 100 fully automates the tray loading process and is uniquely designed to accommodate multiple types of shipping containers. Although the shipping containers described herein are the standard cardboard shipping container, the European standard container, and the RPC, those skilled in the art will appreciate that accommodation of other container types would only require reconfiguration of the adjustments of the various components described above. Those adjustments are within the scope of knowledge of one of ordinary skill in the art. Accordingly, the system 100 is not limited by the specific container types described herein.
The foregoing described embodiments depict different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected”, or “operably coupled”, to each other to achieve the desired functionality.
While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).
Accordingly, the invention is not limited except as by the appended claims.
Patent Application
20120047851
