Method and apparatus for sorting items

(54) Title: APPARATUS TO CLASSIFY ONE (57) Summary: PLURALITY OF ITEMS.

(30) Unionist Priority: 12/01/2007 us 60/884766 (73) Holder (s): Opex Corporation (72) Inventor (s): George Hayduchok, Robert R. Dewitt (74) Attorney (s): Momsen, Leonardos & CIA.

(86) International order: pct US2008051013 from

01/14/2008 (87) International Publication: wo 2008 / 089i50de

24/07/2008

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Jaccard coefficient “APPARATUS TO CLASSIFY A PLURALITY OF ITEMS”

The present application claims the priority of US Provisional Patent Application No. 60/884, 766 filed on January 12, 2007, which is incorporated herein by reference.

Field of the Invention

The present invention relates to a system for automatic classification of items, such as postal items, documents or other items.

Background of the invention

Sorting documents and postal items manually is laborious and time-consuming. For example, thousands of large organizations employ countless people full-time to manually sort and deliver incoming mail and documents between and between offices. For example, a large company may receive 5,000 postal items that need to be sorted and delivered each day to different departments and / or people. Such volumes require a significant number of dedicated employees to sort and deliver mail. However, such a volume is typically not sufficient to justify the cost of traditional automated sorting equipment, which is very expensive. In addition, correspondence for such organizations is typically very diverse, which makes it more difficult, and therefore more expensive to automate classification procedures.

Various systems for classifying have been developed to address the needs of matching environments for large organizations. However, known systems have several problems; the most significant are cost and size. Consequently, there is a need for a compact and conducive automated classification system that is capable of meeting the needs of a medium to large organization, which handles several thousand pieces of postal items per day.

Similarly, large organizations may have extensive storage areas in which numerous items are stored. Sorting and retrieving items from hundreds or thousands of storage areas requires significant work to be done manually, and known systems for automatically handling materials are either too expensive or have limitations that hinder their efficiency. Therefore, there is a need in a variety of material handling applications to automatically store and / or retrieve items.

Summary of the invention

In light of the precedent, a system provides a method and apparatus for classifying items. The system includes a plurality of storage locations, such as boxes, and a plurality of delivery vehicles for delivering items to the storage locations. A track guides delivery vehicles to storage locations.

In one embodiment, a controller controls the operation of the delivery vehicles based on information determined for each item to be classified. In addition, the track may include a plurality of vertical and horizontal sections interconnected so that vehicles can move along a continuous path that changes from a horizontal to a vertical direction. In addition, vehicles can be driven in such a way that the orientation of an item on the vehicle remains constant when vehicles change from a horizontal direction of travel to a vertical direction of travel.

Brief Description of the Drawings

The preceding summary and the following detailed description of the preferred embodiments of the present invention will be better understood when read in conjunction with the accompanying drawings, in which:

figure 1 is a perspective view of a classification apparatus;

figure 2 is a plan view of the classification apparatus shown in figure 1;

figure 3 is a fragmentary perspective view of the classification apparatus shown in figure 1, shown without an entrance station;

figure 4 is a right side view of the classification apparatus shown in figure 3;

figure 5 is a front elevation view of the classification apparatus shown in figure 3, shown without discharge boxes;

figure 6 is a fragmentary sectional view of a charging station for the sorting apparatus shown in figure 1;

figure 7 is a fragmentary perspective view, enlarged, of a portion of the charging station of the apparatus illustrated in figure 3;

figure 8 is an enlarged fragmentary view of a track portion of the apparatus shown in figure 1, showing details of a door in an open position;

figure 9 is an enlarged fragmentary view of a track portion of the apparatus illustrated in figure 1, showing details of a door in a closed position;

figure 10 is a fragmentary perspective view, enlarged, of a portion of the track shown in figure 1, showing details of a door;

figure 11 is a fragmentary perspective view, enlarged, of a portion of the track shown in figure 1, showing details of a door, with the door shown in an open position, in dashed lines;

figure 12 is a top perspective view of a delivery vehicle for the apparatus shown in figure 1;

figure 13 is a plan view of the delivery vehicle shown in figure 12;

figure 14 is a right side view of the delivery vehicle shown in figure 12;

door, with the door shown in an open position, in dashed lines;

figure 12 is a top perspective view of a delivery vehicle for the apparatus shown in figure 1;

figure 13 is a plan view of the delivery vehicle shown in figure 12;

figure 14 is a right side view of the delivery vehicle shown in figure 12;

figure 15 is a front elevation view of the delivery vehicle shown in figure 12;

figure 16 is a bottom perspective view of the delivery vehicle shown in figure 12;

figure 17 is a bottom view of the delivery vehicle shown in figure 12; and figure 18 is an enlarged view of a delivery vehicle wheel shown in figure 12, shown in relation to the track of the sorting apparatus shown in figure 1;

Detailed Description of the Invention

Referring now to Figures 1 - 18, an apparatus for classifying items, such as documents or postal items, is generally designated as 10. Apparatus 10 includes a plurality of delivery vehicles or cars 200 for delivering items to a plurality of delivery locations. classification, such as output boxes 190. At a loading station 310, each cart 200 receives an item from an input station 50 and delivers it to the appropriate box.

Cars 200 travel along a track 110 to the classification sites. The track has a horizontal top rail 135 and a horizontal bottom rail 140, which operates as a return leg. A number of legs of parallel vertical tracks 130 extend5 between the upper rail and the lower return leg. In the present case, the boxes 190 are arranged in columns between the vertical track legs 130.

After a part is loaded onto a carriage, the carriage moves upward along two pairs of vertical track legs and then horizontally along two upper lanes 135. Carriage 200 moves along the upper rail until it reaches the appropriate column that contains the box for the part the car is supporting. Lane 110 includes doors 180 that fire to direct the carriage 200 down the vertical legs and the carriage stops in the appropriate box. The carriage 200 then unloads the part into the box.

After unloading the part, the carriage 200 continues to descend on the vertical legs 130 of the column until it reaches the lower rail 140. Doors open to direct the carriage along the lower rail, and the carriage follows the lower rail to return to the station loading 310 to receive another part.

Cars 200 are semi-autonomous vehicles that each have an internal power source and an internal motor to drive the cars along track 110. The cars also include a loading / unloading mechanism 210, such as a conveyor, for load parts on cars and unload parts from cars.

Since the system 10 includes a number of cars 200, the positioning of the cars is controlled to ensure that the different cars do not collide with each other. In one embodiment, system 10 uses a central controller 350 that tracks the position of each car 200 and provides control signals for each car to monitor the progress of the cars along the track. The central controller 350 can also control the operation of the various elements along the track, such as the

A variety of configurations can be used for the entrance station, including manual or automatic configurations or a combination of manual and automatic features. In a manual system, an operator feeds information for each piece and the system classifies the postal piece accordingly. In an automatic system, the feed or input system includes elements that scan each postal piece and detect information with respect to each piece. The system then classifies the postal item according to the scanned information.

In an example manual configuration, the feeding system includes a workstation that has a conveyor, a feeding device, such as a keyboard, and a monitor. An operator reads information from the postal piece and then drops it onto a conveyor that transports the piece to the loading station 310. Sensors positioned along the track track the piece when the conveyor transports the postal piece towards the loading station. An example of a workstation that has a carrier for receiving dropped parts and tracking parts is provided in pending US Order No. 10 / 862,021, filed on June 4, 2004, which was published on January 27, 2005 under Publication No. US 2005-0018214 Al and which is incorporated here for reference. The carrier receives postal pieces that have been dropped by an operator and tracks the postal pieces when they are transported along the conveyor.

In an example automatic configuration, the system includes an image forming station, which has an image forming device, such as a high speed scanning camera. The imaging station scans each postal piece to detect information regarding the destination for each piece. The system analyzes the image data to determine the destination information and then electronically applies a label on the postal piece with the destination and classifies the piece accordingly. An example of a system that has an automatic imaging station for scanning parts when they are transported is described in US Patent Application No. 09 / 904,471, filed July 13, 2001, which was published January 16, 2001 2003 under Publication No. US 2003-0014376 Al, and which is incorporated herein by reference.

Figures 1 and 2 illustrate such an automatic system. The entry station includes an inbox 55 for receiving a stack of correspondence. A feeder 60 in the inbox serially feeds postal pieces from the input box to a conveyor 65. An imaging station 70 positioned along the conveyor scans the postal pieces when the pieces are transported to the loading station 310. System 10 analyzes the image data to read information for the postal item, such as the address of the recipient.

The carrier 65 transports the postal piece to the loading station 310. At the loading station, the conveyor 65 carries the postal piece onto a car 200. As discussed in more detail below, after the postal piece is loaded onto the car, the car moves away from the charging station and another car moves to the position at the charging station to receive the next piece of mail.

In certain cases, the system may not be able to automatically identify the relevant information for the postal item. To process such parts, the system can include an operator to feed the relevant information so that the postal piece can be classified. For example, the system can include an operator station that has a power device and a display, such as a monitor. If the system cannot automatically determine the address within a predetermined period of time, the system displays the scanned images for the postal piece on the monitor so that an operator at the workstation can view the images and manually feed the information using the device. feed.

In addition to the automatic and manual systems described above, the system can be configured in a hybrid or semi-automatic configuration that has some operations performed manually and others automatically. For example, the system may include a manual entry station, which also has an imaging station. Since the system can handle a wide variety of items, it may be desirable to have an operator who manually feeds the parts so that the parts are properly oriented and separated. The imaging station then scans the items and processes the imaging data to determine the address information for the parts. In addition, an operator station can include a feed device and a display for feeding information if the address for a part cannot be determined automatically, as discussed above. An operator can feed the information as soon as the system indicates to an operator that it cannot determine the information for a part. Alternatively, as discussed below, the car can be driven to a shock absorber if the information for a part cannot be determined. In such a case, cars that have such parts will remain in the buffer while the system continues to process parts for which the system can determine the relevant information. An operator can continue to drop parts manually and wait until a number of parts need manual information manipulation. An operator can then switch from dropping parts to manually manipulating parts, sometimes referred to as local video encoding (LVE). An operator can continue to manipulate until some or all of the parts in the buffer have been successfully coded, and then an operator can resume to manually drop the parts.

Yet, as another alternative, it may be desirable to incorporate a separate operator station that has the feed and display device, so that an operator can feed mail at the entrance station and a separate operator can feed information to parts that have addresses that cannot be automatically determined.

As can be seen from the foregoing, entrance station 50 can be configured in an extensive range of options. The options are not limited to those configurations described above, and may include additional features, such as an automatic scale to weigh each piece, a labeler to selectively apply labels to postal items and a printer to print information about postal items or labels.

In addition, in the preceding description, the system is described as having a single entrance station 50. However, it may be desirable to incorporate a plurality of entrance stations positioned throughout the system 10. Through the use of a plurality of entrance stations, the feed rate of parts can be increased. In addition, entry stations can be configured to process different types of items. In this way, each entrance station could be configured to efficiently process a particular category of items. For example, if the system is configured to process documents, such as correspondence, an input station can be configured to process standard envelopes, while another input station can be configured to process larger correspondences, such as flats. Similarly, an entrance station can be configured to process correspondence automatically by scanning it and automatically determining the recipient. The second entry station can be configured to process waste, such as by manually manipulating information with respect to the recipient.

CLASSIFICATION STATION

With reference to figures 1 - 6, the system includes a sorting station 100, such as an arrangement of boxes 190, for receiving the parts. In the present case, the sorting station includes a number of boxes arranged in columns. In addition, the sorting station 100 includes a track 110 to guide the cars 200 to the boxes 190.

The track 110 includes a horizontal top rail 135 and a horizontal bottom rail 140. A plurality of vertical legs 130 extends between the upper horizontal leg and the lower horizontal leg 140. During transport, the cars move above a pair of vertical legs from the loading station 310 to the top rail 135 (as described below, the cars currently move on two pairs of tracks because the track includes a front track and a opposite parallel track). The car then moves along the top rail until it reaches the column that has the appropriate box. The coir then moves downward along two vertical front columns and two parallel rear columns until it reaches the appropriate box, and then unloads the postal piece into the box. The carriage then continues down the vertical legs until it reaches the lower horizontal leg 140. The carriage then follows the lower rail back towards the charging station.

As can be seen in figure 2, the track 110 includes a front track 115 and a rear track 120. The front and rear tracks 115, 120 are parallel tracks that cooperate to guide the cars around the track. As shown in figure 13, each car includes four wheels 220: two front wheels and two rear wheels. The front wheels 220 roll on the front track, while the rear wheels roll on the rear track. It should be understood that in the discussion of the track, the front and rear tracks 115, 120 are similarly configured as opposite tracks that support the front and rear wheels 220 of the cars. Therefore, the description of a portion of either the front or rear track also applies to the opposite front or rear track.

With reference to figure 18, the details of the track will be described in more detail. The track 110 includes an outer wall 152 and an inner wall 154 that is spaced from the outer wall and parallel to the outer wall. The track also has a rear wall 160 that extends between the inner and outer walls. As can be seen in figure 18, the inner and outer walls 152, 154 and the rear wall form a channel. The car's wheels 220 roll in this channel.

Referring to Figure 11, the track includes both a driving surface 156 and a guide surface 158. The driving surface positively engages the cars to allow the car to move along the track. The guide surface 158 guides the carriage, keeps the carriage in operative engagement with the driving surface 156. In the present case, the drive surface is formed by a series of teeth, forming a rack that engages the wheels of the cars as described in more detail below. The guide surface 158 is a generally flat surface, adjacent to the rack 156. The rack 156 extends approximately through the half of the track and the guide surface 158 extends through the other half of the track. As shown in figures 11 and 18, rack 156 is formed on the inner wall 154 of the track. The opposite outer wall 152 is a generally flat surface parallel to the guide surface 158 of the inner wall.

As described above, the track includes a plurality of vertical legs extending between the horizontal top and bottom rails 135, 140. An intersection 170 is formed at each section of the track where one of the vertical legs intersects one of the horizontal legs. Each intersection includes an inner branch 172 that is curved and an outer branch 176 that is generally straight. Figure 10 illustrates both a right intersection 170a guide 158 of the inner wall.

As described above, the track includes a plurality of vertical legs extending between the horizontal top and bottom rails 135, 140. An intersection 170 is formed at each section of the track where one of the vertical legs intersects one of the horizontal legs. Each intersection includes an inner branch 172 that is curved and an outer branch 176 that is generally straight. Figure 10 illustrates both a right intersection 170c and a left intersection 170, which are mirrors with respect to each other. In figure 10, intersections 170c, 170d illustrate the portion of the track where two vertical legs 130 intersect the upper horizontal leg 135. The intersections of the vertical legs with the lower rail incorporate similar intersections, except that the intersections are reversed. Specifically, the point at which vertical leg 130c intersects the lower rail incorporates a configured intersection similar to intersection 170d, and the point at which vertical leg 130d intersects the lower rail incorporates a configured intersection similar to intersection 170c.

Each intersection 170 includes a pivotable door 180 that has a smoothly curved inner track and a flat outer track that has teeth that correspond to the teeth of the driving surface 156 for the track. Door 180 pivots between a first position and a second position. In the first position, door 180 is closed so that the straight external track 184 of the door is aligned with the straight external branch 176 of the intersection. In the second position, the door is open so that the curved inner track 182 of the door is aligned with the curved branch 172 of the intersection.

Therefore, in the closed position, the door is pivoted downwards so that the outer track 184 of the door aligns with the drive surface 156. In this position, the door blocks the carriage with respect to turning down the curved portion, so that the car remains straight through the intersection. In contrast, as illustrated in figure 10, when the door is horizontal rail or from a horizontal rail to a vertical rail, depending on the location of the intersection.

As can be seen in figure 11, the end of the remote door to the pivot point of the door widens outwards so that the curved inner track adapts to the curved profile of the inner branch when the door is opened. As a result, the door has an L-shaped configuration. To accommodate the extended end of the door 180, the drive surface 156 of the inner branch has a notch or recessed portion. When the door is closed, the notch provides clearance so that the outer track 184 of the door is flat, parallel to the drive surface of the outer branch 176. Also, in the example shown in figure 11, the door is positioned along the rail upper 135 of track 110. When the door is closed, the recess in the inner branch of intersection 170 allows the door to lie flat so that it is aligned with the driving surface of the upper rail.

In the preceding description, the doors allow one of the cars to either continue in the same direction (for example, horizontally) or to rotate in one direction (for example, vertically). However, in some applications, the system may include more than two horizontal rails that intersect the vertical columns. In such a configuration, it may be desirable to include a different track that allows the cars to turn in more than one direction. For example, if a car is moving down the column, the door can allow the car to rotate either left or right down the horizontal rail, or move straight through the vertical column. Additionally, in some applications it may be desirable to allow the cars to move upwards, while in the system described above, the cars only move downwards through the sorting station. If the cars also move upwards at the sorting station, then the doors must be configured to accommodate and guide the cars when the cars move upwards through an intersection.

Doors 180 are controlled by means of signals received from central controller 350. Specifically, each door is connected with an actuator 186 which moves the door from the open position to the closed and back position. There may be any of a variety of controllable elements operable to move the door. In the present case, actuator 186 is a solenoid that has a linearly displaceable piston.

In the preceding description, the sorting station 100 is described as a plurality of outlets 190. However, it should be understood that the system can include a variety of types of destinations, not simply outlets. For example, in certain applications it may be desirable to classify items for a storage area, such as an area on a storage shelf. Alternatively, the destination can be an output device that transports items to other locations. According to an example of an output device, the system can include one or more output conveyors that transport parts out of the sorting system towards a different material handling or processing system. For example, an exit conveyor designated with A can transport parts to a processing center designated with A. Therefore, if a part is to be delivered to processing center A, the carriage will move along the track to exit conveyor A. Once the carriage reaches exit conveyor A, the carriage will be stopped and the piece transferred on exit conveyor A. exit conveyor A will then transport the part to processing center A. In addition, it should be understood that the system can be configured to include a plurality of output devices, such as output conveyors.

In some embodiments, the system may include a plurality of exit conveyors in addition to the exit boxes. In other embodiments, the system can only include a plurality of output devices, such as conveyors, and the system is configured to classify parts for the various output devices. In addition, the system can be configured to retrieve parts from storage locations. In such embodiments, cars can classify parts for a storage location, such as a box. Subsequently, one of the cars can move to the storage location and retrieve the item from the storage location and transport it to one of the output devices.

One way in which cars can retrieve items from storage locations is by adding a carrier to storage locations. In this way, an item in a storage location can be transported via the conveyor to the track. When a car arrives at the storage location, the carrier at the storage location transports the item onto the car, similar to the way in which a part is loaded onto the car on the loading column. Accordingly, the system can classify parts for a plurality of output devices, in addition to classifying parts for a plurality of storage locations before subsequently retrieving or retrieving the parts and transporting the parts to the output devices.

As discussed above, the system is operable to classify a variety of items for a plurality of destinations. A target type is a box; a second type is a shelf or other location on which the item is to be stored; and a third type of destination is an output device that can be used to transport the item to a different location. The system can include one or more of each of these types or other types of destinations.

Delivery vehicles

Referring now to Figures 12-17, the details of delivery vehicles 200 will be described in greater detail. Each delivery vehicle is a semi-autonomous car that has an internal drive system, including an internal power supply. Each car includes a mechanism for loading and unloading items for delivery.

The cart 200 may incorporate any of a variety of mechanisms for loading an item onto the cart and unloading the item from the cart into one of the boxes. In addition, the loading / unloading mechanism 210 can be specifically made for a particular application. However, in the present case, the loading / unloading mechanism 210 is a conveyor belt. Specifically, with reference to figure 12, the loading / unloading mechanism includes a plurality of narrow straps 212 that extend along the upper surface of the carriage. The conveyor belts are reversible. The actuation of the straps in a first direction moves the item towards the rear end of the car; driving the belt in a second direction moves the item towards the front end of the car.

A conveyor motor 255 mounted on the underside of the car drives the conveyor belts 212. Specifically, the conveyor belts 212 come around a front roller 213 at the front edge of the car, and a rear roller at the rear edge of the car. The conveyor motor 255 is connected with the front roller 213 to drive the front roller, thereby operating the conveyor belts.

The car includes four wheels 220 which are used to transport the car along the track 110. The wheels 220 are mounted on two spaced parallel axles 215, so that two of the wheels are arranged along the front edge of the car and two of the wheels are arranged along the rear edge of the car.

Referring to figure 18, each wheel comprises an internal idler roller 224 and an external gear 222 that cooperates with the driving surface 156 of the track. The idler roller 224 rotates freely in relation to the axes, while the external gear is fixed in relation to the axis on which it is mounted. In this way, the rotation of the shaft operates to rotate the gear 222. In addition, the idler roller is dimensioned to have a diameter slightly less than the distance between the rear wall 152 and the lower wall 154 of the track. In this way, the crazy roller can rotate freely within the track, while ensuring that the gear 222 of each wheel remains in operative engagement with the driving surface (i.e. the teeth) 156 of the track. Therefore, when the vehicle is moving horizontally, the rollers support the weight of the car, while gears 222 cooperate with the drive surface 156 of the track to drive the vehicle along the track.

The carriage includes an internal motor 250 for driving the wheels 220. More specifically, the driving motor 250 is operatively connected with the axles to rotate the axles 215, which in turn rotates the gears 222 of the wheels. As shown in figure 16, the drive motor 250 is interconnected with the shafts 215 through a pair of drive belts 254 that are driven by means of the drive motor.

The drive system for the car can be configured to synchronously drive the car along the track. In the present case, the drive system is configured so that each gear is driven in a synchronous manner. Specifically, each gear 222 is connected to one end of the axles in a manner that substantially prevents the rotation of the gear relative to the axis. In this way, each axis drives the two gears fixed in a synchronous manner. Additionally, in the present case, both axes are driven in a synchronous manner so that all four gears are driven in a synchronous manner. There are several mechanisms that can be used to synchronously drive the axes. For example, a pair of drive motors can be used to drive the axles, and the drive motor can be synchronized. However, in the present case, a single drive motor 250 is used to drive both axes. Each shaft includes a timing pulley 226 that is rigidly connected to the shaft to prevent rotation of the pulley in relation to the shaft. Similarly, a timing pulley228 is connected to the motor shaft. The drive belt254 connecting the timing pulley 226 on the shaft to the motor is a timing belt so that the rotation of the driving motor is precisely linked with the rotation of the shaft. Although a single timing belt can be used to drive both axes synchronously, in the present case, a pair of timing pulleys is connected to the motor shaft, and each timing pulley is connected with a corresponding timing pulley on one of the axes, as shown in figure 16.

The drive motor 250 includes a sensor that is operable to detect the rotation of the motor to determine the distance the car has traveled. Since gears 222 are rigidly connected to the shafts, which are, in turn, connected synchronously with the drive motor, the forward distance that the car moves corresponds or can be exactly controlled to correlate with the distance by which the drive motor is moved. Therefore, the distance that a car has traveled along the given route depends on the distance the car engine is rotated.

To detect the rotation of the drive motor 250, the motor includes a sensor 252 to detect the amount of rotation of the drive motor. In the present case, sensor 252 is a Hall sensor. A rotating portion of the motor corresponds to what is referred to as a tic. The sensor detects the number of ticks and sends a signal to the central processor 350, which determines how far along the designated route the car has traveled based on information known about the route and the number of ticks the sensor detects for the engine.

When the car moves along the track, an item on the top of the car may tend to fall out of the car, especially when the car accelerates and decelerates. Therefore, in the present case, the carriage includes a retainer 230 for retaining the element on the carriage during delivery. As illustrated in figures 12-17, retainer 230 is to be held in place, which presses the item against the upper surface of the carriage.

The retainer includes an elongated pivotable arm 232. A tensioning element, such as a spring, tensions the arm down against the upper surface of the retainer 230. The retainer 230 further includes an operator 234 in the form of a tongue. Pushing down on the tab raises the preacher from the top surface of the conveyor to allow a piece to be loaded onto the cart or unloaded from the cart.

The trolley 200 can be driven by means of an external power supply, such as a contact along the rail that provides the necessary electrical energy to drive the trolley. However, in the present case, the carriage includes an internal power source 240 that provides the required energy for both the drive motor 250 and the conveyor motor 255. Additionally, in the present case, the power supply is rechargeable. Although the power supply may include a known power source, such as a rechargeable battery, in the present case, the power supply 240 consists of one or more ultracapacitors. Ultracapacitors are capacitors of extremely high energy density. Capacitors store electrical energy by physically separating positive and negative charges, in contrast to the chemical media that a battery uses. Ultracapacitors have an electrostatic effect, which is more physical than chemical and highly reversible. Ultracapacitors can accept very high amperage to recharge ultracapacitors. Through the use of a high current, ultracapacitors can be recharged in a very short time, such as a few seconds or less.

The carriage includes one or more contacts for recharging the power source 240. In the present case, the carriage includes a plurality of brushes 245, such as copper brushes that are spring loaded so that the brushes are tensioned out. Brushes 245 cooperate with a charging rail at the charging station to recharge the power source, as described in more detail below.

Each car includes at least one and preferably two load sensors to detect items when they are loaded onto the car. The sensor (s) ensures that the postal piece is properly positioned on the car. In the present case, the car includes a front loading sensor 260 and a rear loading sensor 262. The front loading sensor detects the front edge of the item when it is loaded onto the car. The front loading sensor 260 also detects the rear edge of the item to ensure that the entire length of the item is loaded onto the car. Similarly, rear sensor 262 detects the leading edge and in certain cases, it can detect the trailing edge of the postal piece. The loading sensors 260, 262 can be simple I / R sensors that detect the presence or absence of a document or postal item.

Although the car operates in response to signals received from the central controller 350, which tracks the location of each car, the car can also include a reader 265 to read directions along the track to confirm the car's position. For example, each box can be assigned a unique bar code, and the front reader can scan the track or other area around box 190 to which an item is to be delivered. The data that the central processor has regarding the path the car must follow and the data regarding the distance the car traveled based on the data regarding the rotation of the drive motor 250 should be sufficient to determine whether the car 200 is positioned in the appropriate box. However, it may be desirable to double check the car's location before the item is unloaded into the appropriate box. Therefore, the scanner can operate to scan and read information with respect to the box in which the car is stopped. If the scanned data indicates that the box is the appropriate box, then the car unloads its item inside the box. Similarly, the car may have a second reader 266 to read indications adjacent to the rear edge of the car. The second reader 266 can be used in applications in which the system is prepared to use a first series of boxes 190 along the front side and a second series of boxes along the rear side of track 110.

In the preceding description, the cars have drive gears that interact with teeth on the track to guide the cars around the track. Additionally, as described in more detail below in the operating section, the location of the car can be controlled based on information regarding how far the car has traveled. In such applications it is desirable to synchronize the drive wheels of the car. However, in some applications, alternative control systems can be used. For example, the location of the cars can be controlled based on signals from sensors positioned along the track or indicators positioned along the track. In such cases, the cars can be configured to use a drive mechanism that is not synchronous as described above.

As discussed in more detail below, the car even includes a processor to control the operation of the car in response to signals received from the central processor. Additionally, the car includes a wireless transceiver so that the car can continuously communicate with the central processor when it moves along the track.

Alternatively, in some applications, it may be desirable to incorporate a plurality of sensors or indicators positioned along the track. The car may include a reader to detect the sensor signals and / or indicators, as well as a central processor to control the operation of the vehicle in response to the sensors or indicators.

LOADING COLUMN

Referring now to figures 6-7, the details of loading column 300 will be described in greater detail. The loading column 300 is formed adjacent the outlet end of the input station 50. The loading column 300 is formed of a front pair of vertical rails 305a, 305b and a corresponding rear set of vertical rails. The charging station 310 is positioned along the charging column. The loading station 310 is in the position along the track in which the carriage 200 is aligned with the discharge end of the entrance station conveyor 50. In this way, the postal piece of the entrance station can be loaded onto the carriage when it is transported to the car at the entrance station.

Although the central processor 350 tracks the position of the car, an internal sensor 312 is positioned adjacent to the charging station 310. When the internal sensor detects the car, the position for the car is known relative to a fixed point along the track, and the central processor resets the car's position to home or zero.

With reference to figure 7, a pair of loading rails is arranged along the vertical rails 305a, 305b. The charging rails are conductive strips connected with an electrical supply. The loading contacts 245 of the carriage 200 engage the conductive strips to recharge the ultracapacitors 240. Specifically, the brush tensioning element 245 tensions the brushes out towards the loading contacts. The electricity flowing through the charging contact 245 is a source of high amperage, low voltage, which allows the ultracapacitors to recharge in a few seconds or less. In addition, since the power supply provided by the ultracapacitors only lasts a few minutes, the car recharges every time when it travels through the charging column.

In addition, it may be desirable to incorporate a starting loading rail similar to the loading rails described above, but arranged along either the return rail or the rails in the column adjacent to the loading column, depending on where the cars are stored when the cars are turned off. Since cars use ultracapacitors, it is possible that ultracapacitors will discharge themselves while the system is off. Therefore, at the start, the cars will have no load and will not be able to move to the loading column to load the ultracapacitors. Therefore, the system can include a starting loading rail arranged along a track that the cars contact when the cars are stored during shutdown. If the cars are stored in the loading column and in the adjacent column during shutdown, then the starting rail is arranged in the column adjacent to the loading column. Alternatively, if the carriages are stored on the return rail and on the loading column during shutdown, then the start rail is arranged along the return rail. In this way, when the system is started, a loading current is supplied to the cars via the starting loading rail and the loading rail on the loading column.

As previously discussed, each carriage 200 includes a retainer 230 for holding items on the carriage during transportation. The retainer must be opened at the charging station to allow an item to be loaded onto the cart. Therefore, as shown in figure 6, an actuator 316 is positioned along the column. The actuator 316 projects inwards towards the cars when the cars are transported upwards in the loading column. When a carriage is transported upward on the loading column 300, the clamping actuator 316 contacts the clamping operator or the tongue 236. The interaction between the actuator 316 and the tongue 236 causes the retainer to open, so that items can be loaded onto the car. When the carriage moves upward to after the actuator 316, the tongue 236 on the carriage disengages the actuator, thereby releasing the retainer, thereby holding or pressing the postal piece against the upper surface of the vehicle.

In the preceding description, the charging station was described as the column on which an item is loaded onto the cart and the cart then moves upwards to the horizontal top rail 135. However, in some applications it may be desirable to configure the charging station so that items are loaded onto the cars at or near the top of the vertical column. In such an application, the load on the cars would be reduced since the car will not have to lift the loaded item on the car. To load items onto the cars on top of the conveyor, a vertical conveyor can be added to the system. For example, an up-angled conveyor can transport items up to the top of the column to load items onto cars. Alternatively, one or more of a variety of carrier configurations can be used to transport items to the top of the loading column to load items onto cars.

Operation

System 10 operates as follows. An item is processed at input station 50 to identify a feature of the part that is indicative of which wave the part should be classified. For example, the item may be the postal item that must be classified according to the department, box number or recipient. If postal pieces are classified by the department, the piece can be processed to identify either a department indicator (such as box number) or the piece can be processed to identify the recipient. The central controller maintains a database that correlates with various data to identify the destination box. For example, the database can correlate recipient names with the appropriate department if the correspondence is being classified according to the department. In other embodiments, the part can be a part that has a product code and the database can correlate the product code with the place of classification.

As previously discussed, the entry station can process items automatically or manually. In a manual mode, an operator manually feeds information regarding a part and then drops the part on a conveyor. The system electronically identifies the part with the classification information and the transporter transports the part to the loading station. Alternatively, if the feeding system stops to an automatic system, the part is automatically scanned to identify the relevant classification characteristic. For example, the input station can use a scanner, such as a barcode scanner to read the postal code on a part, or the input station can include an image forming device, such as a scanning scanner. high speed line, in combination with an OCR engine to read information about the part.

To prepare to receive an item, a car 200 moves along the track towards the charging station 310 in the loading column 300. When the car approaches the charging station, an operator 236 for the latch 230 engages the actuator 316, which pivots the clamping upwards to prepare the car to receive an item, as illustrated in figure 6. When the cart 200 moves into position at the charging station 310, the home sensor detects the presence of the cart and sends a signal to the central processor 350 indicating that the cart is positioned at the charging station. In the following description, the item being classified is described as a postal item. It should be understood that such an item is an example application of the system. As described above, the system can be configured to classify a variety of items in a variety of material handling applications.

Once when the car is positioned at the charging station, the entrance station transports the postal item over the car. When the postal piece is being transported on the carriage 200, the loading mechanism 210 on the carriage loads the postal piece on the carriage. Specifically, the entrance station transports the postal piece for contact with the conveyor belts 212 on the car. Conveyor belts 212 rotate towards the rear side of the car, thus driving the postal piece back over the car.

The operation of the conveyor belts is controlled by means of loading sensors 260, 262. The front loading sensor detects the front edge of the postal piece when the postal piece is loaded onto the carriage. Once when the front loading sensor 260 detects the rear edge of the postal piece, an internal controller in the carriage determines that the postal piece is loaded on the carriage and stops the conveyor engine. In addition, the internal controller can control the operation of the conveyor in response to signals received from rear sensor 262. Specifically, if rear sensor 262 detects the front edge of the post piece, then the front edge of the post piece is adjacent to the rear edge Of car. To ensure that the post piece is not suspended from the rear edge of the carriage, the controller can stop the carrier once when the rear sensor detects the front edge of the post piece. However, if the rear sensor detects the front edge of the postal piece before the front sensor detects the rear edge of the postal piece, the controller can determine that there is a problem with the postal piece (that is, it is too long or two postal pieces overlapping were fed over the car, in such a case, the car may report an error message to the central controller, which can declare an error and provide an indicator to an operator that the car at the charging station requires attention. Alternatively, a refuse box 325 can be positioned behind the charging station so that postal pieces on the cart at the charging station can be ejected into the refuse box 325. In this way, if there is an erroneous loading of the postal piece onto a car, the postal piece can simply be ejected into the refuse box, and a subsequent postal piece can be loaded onto the car.

After the postal piece is loaded onto the carriage, the carriage moves away from the loading station. Specifically, once when the internal controller detects that the postal piece is properly loaded on the carriage, the internal controller sends a signal to start the drive motor 250. The drive motor 250 rotates the axes, which, in turn, gears 222 rotate on wheels 220. The gears 222 mesh with the driving surface 156 of the vertical rails 305 on the loading column to drive the carriage upwards. Specifically, the gears and the drive surface mesh and operate as a rack and pinion mechanism, transforming a rotational movement of the wheels into a linear movement along the track 110.

Since the cars move over the loading column from the charging station, the destination for the car does not need to be determined until after the car reaches the first door along the top rail 135. For example, if a automatic system is used at the entrance station to scan and determine the characteristic used to classify postal items, it may take some processing time to determine the relevant characteristic. The time it takes to transport the postal piece over the car and then transport the car over the loading column will typically be sufficient time to determine the relevant characteristic for the postal piece. However, if the characteristic is not determined by the time the car reaches the top rail, the car can be driven under the second column, which is the column that follows the loading column. The carriage moves down from the second column to the lower rail 140, and then back to the loading column. The car can stop at the second column to provide additional time to determine the characteristic. However, after waiting for a predetermined period, the system can declare that the address cannot be determined and the car can be advanced from the second column and the part can be unloaded to a refuse box. Alternatively, instead of declaring an error, the car can continue to move around the link from the loading column to the second column until the characteristic is determined or until a predetermined time at which the central controller declares an error. In addition, instead of using the junk box when the system is unable to determine the characteristic for the postal item, one of the boxes in the second column can also be used as the junk box. In this way, the cars are ready to receive the postal item as soon as the car arrives at the loading station, without having to eject the problem postal piece into the refuse box 325 at the loading station.

As described above, the system includes a link that can be used as an intermediate track to provide additional processing time to analyze the characteristic for the postal piece, if necessary. Although the first and second columns can be used as the intermediate link, other columns can be used as the intermediate link, if desired.

The preceding discussion described the car buffering process if the system is unable to determine the characteristic for the postal piece by the time the car arrives or reaches the upper rail. However, for most postal items, the system must be able to identify the characteristic without having to store the car in between. The following description describes the operation of the system considering that the characteristic for the postal piece is determined before the carriage reaches the top rail 135.

Once when the characteristic for the postal piece is determined, the central controller 350 determines the appropriate box 190 for the postal piece. Based on the location of a box for the postal item, the route to the car is determined. Specifically, the central controller determines the route to the car and communicates information to the car regarding the box in which the postal item is to be delivered. The central controller then controls the doors along the track to direct the car to the appropriate column. Once the car reaches the appropriate column the car moves under the column to the appropriate box. The carriage stops at the appropriate box 190 and the internal controller sends an appropriate signal to the conveyor motor 255 to drive the conveyor belts 212, which propel the postal piece forward to unload the postal piece into the box. Specifically, the top of the cart aligns with the interstice between the appropriate box 190 and the bottom edge of the box which is immediately above the appropriate box.

As discussed above, central controller 350 controls the operation of ports 180 in response to the location of the carriage 200 and the route the carriage must follow to deliver the postal piece. Additionally, as discussed below, the central controller controls the doors in response to the position of other cars on the track.

When the carriage 200 moves along the upper rail 135 and approaches the column, the doors for the vertical rail 130 are controlled

As discussed above, central controller 350 controls the operation of ports 180 in response to the location of the carriage 200 and the route the carriage must follow to deliver the postal piece. Additionally, as discussed below, the central controller controls the doors in response to the position of other cars on the track.

When the carriage 200 moves along the upper rail 135 and approaches the column, the doors to the vertical rail 130 are controlled as follows. If the car is to pass over the column on the road to the next column, the doors are moved to the closed position, as shown in figure 9. Specifically, both doors at the top of the column are closed so that the outer track 184 of the door aligns with the straight track, with the outer track aligning with the drive surface 156 of the track 110. In this way, the doors they provide a straight drive surface that cooperates with the drive surface 156 to allow the carriage to move over the column.

When the car goes to the column in which it has to return, the doors are controlled as follows. Referring to figure 5, the columns can be seen without the boxes attached. The view in figure 5 is from the front of the device 10, so the car will be moving along the top rail from right to left in the perspective of figure 5. In the following description, the car to be transported to the box in the column it is designated with C in figure 5. Column C includes two pairs of vertical legs. The first pair are front and rear vertical legs 130c on the left side of column C; the second pair are front and rear legs 130d on the right side of column C.

In order for the car to move under column C, the wheels on the left side of the car have to move under legs 130c and the wheels on the right side have to move under legs 130d. Therefore, when the car approaches column C, the doors at the top of

130d are moved to the closed position so that the wheels on the left side remain on the top rail and pass over the legs on the right side 130d. After the wheels on the left side of the car pass over the right legs 130c, the doors 180 on top of the right legs 130d are moved to the open position so that the wheels on the right side can turn the legs 130d downwards. Specifically, after the wheels on the left side pass the right legs 130d, the central controller operates the solenoids 186 of the doors 180 on top of the legs 130 to move doors to the open position, as shown in figure 8 (note that the view in the figure 8 is taken from the rear side of the device so that the perspective of the doors is reversed in relation to the front side). Doors 180 block the straight path through intersection 170 and the curved inner track 182 of the doors drives the wheels on the right side under the vertical legs 130d. Similarly, the doors 180 on the top of the left side legs 130c are moved to the open position to direct the left side wheels under the vertical legs 130c.

When the car approaches the intersections at the base of the legs 130c and 130d, the doors are opened similarly to the description above, but in reverse. Specifically, when the carriage approaches intersections 170 at the base of legs 130c and 130d, doors 180 at intersections are moved to the open position so that the doors direct the front and rear wheels to return the bottom rail. From the perspective of figure 5, the carriage moves from left to right after the carriage reaches the bottom rail. After the car passes through the intersections at the base of the rails 130b, 130d, the doors at the base of the right side legs 130d are moved to the closed position before the wheels on the left side of the car reach the intersection at the base of the side legs right 130d. In this way, the wheels on the left side of the car pass straight through the intersection at the base of the legs 130d along the lower rail 140.

which transmits a signal to the central controller indicating that it is in the vicinity of the door that must be triggered. In addition, the car may include an indicator that can be scanned when the car approaches the door. Based on the indicator and the known destination for the car, the door may fire. Additionally, the car may also include a mechanical actuator that selectively fires or acts on the door to properly steer the car.

One of the advantages of the system as described above is that the orientation of the carriages does not change substantially when the carriages move from horizontal displacement (along the upper or lower rails) to vertically (below one of the columns). Specifically, when a car is moving horizontally, the two front gear wheels 220 cooperate with the top or bottom rail 135 or 140 of the front track 115, and the two rear gear wheels 220 cooperate with the corresponding top or bottom rail 135 or 140 of the rear track 120. When the car passes through the door and then into the column, the two front gear wheels engage a pair of vertical legs 130 on the front track 115, and the two rear gear wheels engage the corresponding vertical legs on the rear track 120.

When the car moves from the horizontal rails to the vertical columns or from the vertical to the horizontal, the tracks allow all four geared wheels to be positioned at the same height. In this way, when the car moves along the track, it does not skid or lean when it changes between horizontal and vertical movement. In addition, it may be desirable to configure the cars with a single axle. In such a configuration, the car would generally be oriented vertically, as opposed to the generally horizontal orientation of the cars, described above. In the single axle configuration, the weight of the cars would maintain the orientation of the cars. However, when using a single-axle car, the orientation of the classification locations would be reconfigured to accommodate the vertical orientation of the cars. Similarly, the loading station would also be reconfigured to load parts onto the cars in vertical orientation.

Traffic control

Since the system includes a number of cars 200, the system controls the operation of the different cars to ensure that the cars do not collide with each other. In the following description, this is referred to as traffic control.

A variety of methodologies can be used for traffic control. For example, traffic control can be a distributed system in which each car monitors its position in relation to adjacent cars and the internal controller controls the car accordingly. An example of such a system uses proximity sensors on each car. If the proximity sensor for a car detects a car within a predefined distance in front of the car, the internal controller for the rear car can control the car by slowing down or stopping the rear car. Similarly, if a car detects a car within a predefined distance behind the car, the front car can increase speed unless the front car detects a car ahead of it within the predefined distance. In this way, cars can control car speed independently based on feedback from proximity sensors.

Although the system can use a distributed system for traffic control, in the present case the system uses a centralized system for traffic control. Specifically, the central controller 350 tracks the position of each car 200 and provides traffic control signals for each car based on the position of each car in relation to adjacent cars and based on the route for each car.

In the present case, the central controller 350 operates as the traffic controller, continuously communicating with the cars when the cars move along the runway 110. For each car, the central controller determines the distance that each car can travel, and communicates this information to cars. For example, if car B is following car A along the track, and car A is at point A, car B can safely move to a point just before point A without colliding with car A. When the car A advances to a subsequent point B along the track, car B can safely move to a point just before point B without colliding with car A.

The cars continuously communicate with the central controller to provide information indicative of their positions, so that the central controller can continuously update the safe distances for each car when the cars advance around the track.

Although the preceding discussion is limited to determining safe zones based on the positions of the various cars on the track, the determination of safe zones is done based on other factors that affect traffic. For example, when calculating the safe distance for a car, the central controller considers the distance between the car and the next door, as well as the distance to the destination box for the car.

As can be seen from the precedent, increasing the frequency of communication between the cars and the central controller increases the efficiency of the traffic flow along the track. Therefore, in the present case, traffic control is designed to communicate with a car once when, for every inch, the car moves along the track. Therefore, if a car moves at 25 inches per second, the central controller communicates with the car every 40 msec. Also, it is desirable to have the cars moving up to 50 inches / sec. Therefore, it is desirable to configure communications to allow cars to communicate with the central controller every 20 msec.

In addition to the preceding variables used to calculate safe distances, information regarding the track profile in front of each car is used to calculate safe distances. For example, the central controller determines whether the path ahead of a car is sideways movement, uphill movement (that is, vertically upward movement) or downward movement (that is, vertically downward movement).

One of the problems in traffic control concerns the transition at intersections 170. The problem arises when a car needs to go through the transition on return rail 140. If two cars arrive at the intersection close enough to collide, one of the cars must have priority and the other car needs to wait or slow down to allow the first car to pass.

A first method for controlling transition traffic is based on determining the next intersection large enough for a car to have time to pass through an intersection without colliding with another car. In other words, if a first car approaches an intersection and it is determined that the intersection between the first car and a second car is not sufficient for the first car to pass through, the first car waits at the intersection until there is an intersection or distance big enough to allow the first car to pass.

A second method for controlling transition traffic is based on determining which car is closest to the internal sensor at the 310.0 charging station. Car with the shortest distance with respect to the internal sensor has priority at the intersection.

Another factor that the traffic controller considers when calculating safe distances refers to the position of cars in adjacent columns. In the present case, most adjacent columns share a common vertical track. For example, in figure 19, the leftmost column uses vertical rails 130x and 130y. The column next to the 310 charging station column. The car with the shortest distance with respect to the internal sensor has priority at the intersection.

Another factor that the traffic controller considers when calculating safe distances refers to the position of cars in adjacent columns. In the present case, most adjacent columns share a common vertical track. For example, in figure 15, the leftmost column uses vertical rails 130a and 130b. The column after the leftmost column uses vertical rails 130b and 130c.

However, in the present case, some of the columns may have two vertical rails 130 that are independent of the adjacent columns. For example, loading column 300 has two independent rails that are not shared with the adjacent column. Therefore, cars can move upwards in the loading column without considering the position of cars in the column after the loading column. In addition, as shown in figure 15, it may be desirable to configure the column next to the loading column so that it also has two independent vertical tracks. In this way, cars can move more freely up the loading column and down the adjacent column to provide a buffer link, as previously described.

Therefore, when calculating safe distances, the traffic controller evaluates the position of cars in adjacent columns if the cars share a common vertical track to ensure that the two cars do not collide when the car moves under the adjacent columns.

In the preceding discussion, the item classification was described in relation to an arrangement of boxes arranged in front of the classification station 100. However, as illustrated in figures 2 &amp; 4, the number of boxes in the system can be doubled by fixing a rear box arrangement.

In addition, the sorting station 100 is modular and can be easily expanded, when necessary, simply by attaching an additional section to the left end of the sorting station. Yet, although the precedent describes the box arrangement as essentially a two-dimensional arrangement, in which the cars simply move in the X and Y directions, the sorting station can be expanded to add additional lane runs. Specifically, a separate sorting station, parallel or perpendicular to the sorting station illustrated in figure 2, can be connected to the sorting station. In this way, the car would move in a third dimension in relation to the X and Y directions of the classification station illustrated in figure 2. For example, additional sections of the track can be connected with the classification station shown in figure 2, perpendicular to the illustrated classification station, so that the additional track forms an L shape that intersects the loading column. In such a configuration, doors selectively drive the cars either down the top rail 135 or back towards the additional lane. Similarly, a plurality of parallel rows of sorting stations can be interconnected, so that the cars selectively move along an intersection track until the car reaches the appropriate row. The carriage then moves down the row until it reaches the appropriate column, as described above.

It will be recognized by those skilled in the art that changes or modifications can be made to the above described embodiments without departing from the broad inventive concepts of the invention. For example, in the preceding description, the operation of the rating station is described as being centralized with the central controller. However, it may be desirable to have the cars controlling the operation of the doors. According to an alternative, the cars incorporate one or more mechanical actuators that cooperate with an operator at the door. The actuators on the cars are operable between first and second positions. In the first position, the actuator engages the door operator to move the door to the closed position. In a second position, the actuator engages the door to move the door to the open position. Alternatively, the door can be tensioned towards the open position, so that when the car actuator is in the second position, it does not engage the door operator. Alternatively, each car includes a mechanism for communicating with each door. If the door needs to be pivoted to direct an approaching car along a particular route, the car sends a signal to the door indicating whether the door should be opened or closed. In response to the signal from the car, the door pivots to the appropriate position.

Also, in the description above, the system uses wireless communication between the cars and the central controller. In an alternative embodiment, a communication line can be installed on the track and the cars can communicate with the central controller via a communication connection connected by cables. Additionally, the system was described as being useful in the classification of incoming correspondence. However, the system can also be used to classify and prepare outgoing or outgoing mail. For example, after determining a characteristic for the post piece, the system can print a mark on the post piece. For example, after determining the recipient's address for the postal item, the system determines which mailbox the postal item should be sent to. When the postal piece is transported to the box, a printer prints the appropriate postnet barcode on the piece before classifying the piece. To provide printing functionality, the system can include a printer arranged along the track. When the carriage approaches the printer, the carriage stops and at least partially unloads the postal piece to extend the postal piece towards the printer. The printer then prints the appropriate postnet code. The carriage then reverses the conveyors to load the part back onto the carriage each time, and then moves to the appropriate box. Similarly, the system may include a device for selectively applying labels to parts. Similar to the example above of applying print marks on the parts, the labeler can be positioned along the track. The cars selectively stop at the labeler en route to the appropriate box and at least partially unload the postal item towards the labeler. The labeler then applies a label on the postal piece and the carrier on the car then reverses to load the piece back onto the car.

In addition to mailing applications, it may be desirable to incorporate a printer and / or a labeler in systems configured to process incoming mail. For example, when sorting incoming postal items, it may be desirable to print certain information, such as classification codes, a date stamp, or track control information about some or all of the parts being processed. In some cases, such information can be printed directly on the postal items. In other cases, a label can be applied to postal items and information can be printed on the label.

In addition to a printer and a labeler, the system can include a scale to weigh the postal items. The scale can be positioned along the track 110, as well as along the loading column. To weigh a part, the carriage stops adjacent to the balance, and ejects the part from the carriage on the balance by driving conveyor belts 212. Preferably, the scale includes a conveyor or transfer mechanism for unloading the part from the scale and back onto the car or on a subsequent car. When the part is loaded onto the cart from the scale, the cart drives the conveyors to load the part, as discussed above in connection with the loading station.

Therefore, it should be understood that this invention is not limited to the embodiments described above, but is intended to include all changes and modifications that are within the scope and spirit of the invention as set out in the claims.