System And Method Of Loading Mail Articles With A Transfer Unit
A mail processing system has an infeed line coupled to receive a first article from a feeder. A loading device is coupled to receive the first article from the infeed line, and a transfer unit is coupled to receive the first article from the loading device. A transport vehicle is configured to move in proximity of the transfer unit along a first linear path, wherein the transfer unit is configured to move synchronously and parallel to the first transport unit, and wherein the transfer unit is configured to transfer the first article to the first transport vehicle.
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The present application claims priority to provisional patent application Ser. No. 60/624,499 filed on Nov. 2, 2004, which is herein incorporated by reference.
BACKGROUND OF THE INVENTIONThe various embodiments described herein relate to a mail processing system and a method of loading articles onto a transport system.
Each day the United States Postal Service (USPS) processes articles for delivery to millions of individual domestic addresses. As used throughout the application, articles refer to mail items, magazines, books and other such flat items. Before mail carriers begin to walk through or drive through their delivery routes, a mail processing system at a USPS processing site sorts all articles for the carriers and packages the sorted articles for each domestic address. A carrier's responsibility includes putting all of these articles into an appropriate sequence for efficient delivery to the domestic addresses.
The mail processing system is highly automated to handle the amount of daily articles. It includes a delivery point packaging (DPP) system that, for example, separates the articles, reads their destination addresses and groups the articles based upon their respective destination addresses. One example of a DPP system includes an arrangement of a multitude of individual slots for individual articles. A transport system having containers with pockets transports the articles along a track system to the slots. Feeders or loaders insert the articles into the transport system at loading points. At this point, the destination address of an article is known and the transport system transports the article along a delivery path to a slot that is pre-assigned to the destination address of that article.
A general aspect of a mail processing system is to operate it as efficient and reliable as possible, but at the same time without causing any or too much damage to the articles. One area in the mail processing system that influences efficiency, reliability and potential damage are the loading points. For example, to achieve a high throughput a loader needs to insert an article into a pocket as fast as possible, and to load as many pockets as possible. Hence, the pockets on the transport system should be densely packed and have openings that are only slightly larger than the thickness of an article, but still wide enough to ensure safe and reliable loading.
Known techniques for loading the articles include, for example, 1) stopping the transport system, 2) feeding an article while the transport system moves and passes the loader, or 3) using a loader having a swivel arm that follows the moving transport system. However, these techniques require the transport system to generate high acceleration forces after each stop (1), the loader to insert the article with a high speed, which increases the risk of damage to the article, while the pocket opening needs to be relatively large (2), or the pocket openings need to be relatively large to compensate for any angle aberrations.
SUMMARY OF CERTAIN INVENTIVE ASPECTSThere is, therefore, a need for an improved technique for loading articles in a mail processing system so that it can operate as efficient and reliable as possible without causing any or too much damage to the articles.
Accordingly, one aspect involves a method of delivering articles to predetermined delivery locations within a mail processing system. A first article is transferred from an infeed line to a loading device, and then from the loading device to a transfer unit. The transfer unit is moved synchronously and parallel to a first transport unit that moves in proximity of the transfer unit in a first direction along a linear path. The first article is transferred from the transfer unit to the first transport vehicle.
Another aspect involves a mail processing system having an infeed line coupled to receive a first article from a feeder. A loading device is coupled to receive the first article from the infeed line, and a transfer unit is coupled to receive the first article from the loading device. A transport vehicle is configured to move in proximity of the transfer unit along a first linear path, wherein the transfer unit is configured to move synchronously and parallel to the first transport unit, and wherein the transfer unit is configured to transfer the first article to the first transport vehicle.
A further aspect involves a loader and indexer unit for a mail processing system. The loader and indexer unit includes an infeed line coupled to receive a first article from a feeder. A loading device is coupled to receive the first article from the infeed line, and a transfer unit is coupled to receive the first article from the loading device. The transfer unit is configured to move synchronously and parallel to a first transport unit configured to move in proximity of the transfer unit along a first linear path. The transfer unit is further configured to transfer the first article to the first transport vehicle.
BRIEF DESCRIPTION OF THE DRAWINGSThese and other aspects, advantages and novel features of the embodiments described herein will become apparent upon reading the following detailed description and upon reference to the accompanying drawings. In the drawings, same elements have the same reference numerals.
Briefly, the feeding section FS separates individual articles from batches to identify their individual destination addresses. For that purpose, the feeding section FS includes in one embodiment feeders 3, 5 and optical character readers (OCR) or bar code readers, or a combination of these readers (see also
The infrastructure includes, among other elements, elevators and transport devices 8, such as transport vehicles 8, for example, automatic inserter transport vehicles, hereinafter referred to as ANTs 8, that transport the articles in pockets. A summary of the general operation of an ANT 8 is set forth below. In one embodiment, the system may include several hundred ANTs 8. Those of ordinary skill in the art will appreciate that such ANTs 8 are only examples of transport devices, and that other transport devices, such as containers on a belt system, may be used, as well.
The various embodiments of the mail processing system described hereinafter relate mainly to the feeder section and the routing area. Accordingly,
The function of each loader-indexer unit 10, 12 is to transition the articles from infeed line transport belts to the ANT 8. The loader-indexer units 10, 12 are each positioned in the path of an ANT 8. The articles move from the feeders 3, 5 via the belts of the infeed lines 14, 16 to the loader-indexer unit 12, in
The loader 10a is the transport interface to the infeed line 14 and takes over articles from the infeed line transport belts. It transports an article until its trailing edge has left the loader at the ANT interface. This function also includes the synchronization of the transport speed with the infeed transport speed. In certain embodiments, it may not be desired to reach the final article position within the ANT 8 with full speed. Hence, the speed may have to be adjusted, e.g., reduced, at the end of the insertion process, but prior to transferring the article to the ANT 8, so as to reduce its kinetic energy, as mentioned above. Also, the loader 10a is responsible for controlling an ANT 8 to provide access to a pocket, i.e., to open a pocket. The loader 10a further synchronizes and aligns itself with the moving ANT 8. The loading process into the ANT 8 starts, when the front edge of the article leaves the loader, and ends when the rear edge of the article has left the loader 10a.
Several points may be defined to characterize or describe the loading and indexing process. A feed point FP is at an interface between the feeder 3 and the infeed line 14, and is the location where the front edge of the article is traveling at a predetermined and constant transport speed. A load point LP is at an interface between the loader 10a and the indexer 10b and, hence, at a location where the article's trailing edge has cleared the loader 10a. Once the article left the loader 10a, the loader 10a or the ANT 8 are then ready for the next cycle. A decision point DP is in proximity of an entry into the buffer 18, and defined as a projection of the article's travel time from the feed point FP to the load point LP onto the track of the ANT 8. Ideally an ANT 8 reaches the decision point DP when an article is ready at the feed point FP, the article and this ANT 8 will meet at the load point LP just in time for loading the article onto the ANT 8. When the article is fed after the ANT 8 has passed the decision point DP the ANT 8 has to wait in the buffer 18. An index point IP is defined within the infeed line 14 in proximity of a transition to the loader 10a. When an article reaches the index point IP the indexer 10b starts taking over an ANT 8 at the interface to the buffer 18.
When an ANT 8 enters the area between the decision point DP and the transition to the indexer 10b an article is fed at the feed point FP. When the article is fed and the ANT 8 is exactly at the decision point DP it proceeds through the loading cycle without additional delay. However, if an article is fed after the decision point DP the ANT 8 has to stop and wait. In order to eliminate tolerances in the article's travel time between the decision point DP and the transition to the indexer 10b the ANT 8 stops in one embodiment at the end of the buffer 18 in any case.
An article enters the infeed line 14 at the feed point FP with the front edge traveling at a transport speed V1. The article travels through the infeed line 14 until the leading edge reaches the load point LP. The ANT 8 should then be ready to be loaded at this point. Transport of the article at a constant speed (V1) continues until its rear edge reaches in one embodiment a deceleration point within a transfer unit (see
Prior to the indexer 10b, the control system of the infeed section synchronizes ANTs and the feed process. Articles that pass the index point IP trigger the indexer 10b to take over an ANT 8 waiting at the end of the buffer 18. The speed of the ANT 8 is zero (V=0). During the transition from the buffer 18 to the indexer 10b the ANT drive is initially switched 3 off and then turned on. The ANT 8 accelerates to a predetermined speed (see also
The loading arm 20 may be configured as a symmetrical arrangement, as shown in
To avoid the article having to turn left or right at the center of motion M1, the infeed line 14 may be positioned at an angle with respect to the regular position of the loading arm 20. For example, in an embodiment similar to that of
In one embodiment, the transfer unit 22 includes a belt system 40 mounted on a structure 36 that is movably mounted to a pair of parallel guide rails 38. The respective ends of the guide rails 38 limit the movement of the structure 36 in each direction. The structure includes a first transport unit 36a (master sled) and a second transport unit 36b (slave sled) that are each mounted on the guide rails 38. Each transport unit 36a, 36b is coupled to a servo drive that controls the operation (e.g., the movement) of the respective transport unit 36a, 36b.
The first transport unit 36a, in transport direction of the articles positioned to the right, is assigned to follow the ANT 8. This allows performing the loading process without interruption. The first transport unit 36a includes a first belt 40a (right belt) of the belt system 40 for transporting the article. The second transport unit 36b moves on the guide rails 38 independently of the first transport device 36b. Further, the second transport device 36b includes a second belt 40b (left belt). These belts 40a, 40b receive an article between them and forward the article to the ANT 8. Hence, the speed of the belts 40a, 40b determines the speed the article enters the ANT 8. The speed can be adjusted, for example, reduced, to slow down the article and thus reduce the kinetic energy the ANT 8 needs to absorb. The pockets that receive the articles may be provided with attenuating means to absorb the remaining kinetic energy. This further reduces the risk of damage to the articles and advantageously reduces the noise level, as well.
Before an article enters the transfer unit 22, the distance between the first and second transport units 36a, 36b is adjusted to the thickness of the article. This allows applying the force necessary for transporting the article between the belts 40a, 40b. For example, prior to accelerating the article, the distance is reduced to generate an increased force. This process is controlled by measuring the force directly at the second transport device 36b, or indirectly by means of controlling the torque or the current of the servo drive.
As mentioned above, the ANT 8 is in one embodiment an autonomous vehicle designed to carry one article from one of two loading points and deliver it to one of many delivery point slots. To perform this task the ANT 8 includes communications equipment that provides for communications between the ANT 8 and the system acting as a host. The transport system moves the ANTs 8 within the mail processing system. Within the transport system the ANTs 8 travel on a track system. In one embodiment, the track system is based on a monorail that serves as a railway for the ANTs 8. The track system includes switches that allow the ANTs 8 to change from one rail path to another. For example, as the ANT 8 approaches a switch it sends a signal to the switch that indicates the desired direction. The switch “knows” its own switch position, processes the indicated direction and changes its switch position, if necessary, to divert the ANT 8 to the appropriate rail.
It is apparent that there has been disclosed a mail processing system and a method of delivering articles to predetermined delivery locations within the mail processing system that fully satisfies the objects, means, and advantages set forth hereinbefore. For example, the articles can be fed to the ANTs 8 along a substantially straight path. Further, during the process of transferring an article from the transfer unit 22 to the ANT 8 the interface characteristics, such as gaps or angle, between these two devices (8, 22) do not change. This makes the transfer process more reliable. In addition, components of the loading device 20, such as guides and drives, are easier to implement, for example, because the loading device 20 pivots only around a relative small angle. While specific embodiments of the system and method have been described, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description.
Claims
1. A method of delivering articles to predetermined delivery locations within a mail processing system, comprising:
- transferring a first article from an infeed line to a loading device;
- transferring the first article from the loading device to a transfer unit;
- moving the transfer unit synchronously and parallel to a first transport device that moves in proximity of the transfer unit in a first direction along a linear path; and
- transferring the first article from the transfer unit to the first transport device.
2. The method of claim 1, further comprising stopping the loading device and the transfer unit at a first limit and moving them against the first direction to a second limit for initiating a transfer of a second article to a second transport device.
3. The method of claim 1, wherein moving the transfer unit causes the loading device to pivot at a first center of motion with respect to the infeed line, wherein the first center of motion is at a transition from the infeed line to the loading device, and at a second center of motion with respect to the transfer unit, wherein the second center of motion is at a transition from the loading device to the transfer unit.
4. The method of claim 3, wherein the infeed line extends in a direction that is substantially perpendicular to the linear path along which the transport vehicle moves.
5. The method of claim 4, further comprising guiding the first article at the first center of motion towards a left side and at the second center of motion towards a right side.
6. The method of claim 4, further comprising guiding the first article at the first center of motion towards a right side and at the second center of motion towards a left side.
7. The method of claim 4, further comprising guiding the first article at the first center of motion and at the second center of motion along a substantially straight line.
8. The method of claim 3, wherein the infeed line and the linear path along which the transport vehicle moves include an acute angle.
9. The method of claim 8, further comprising guiding at least the first article at the first center of motion towards a right side.
10. The method of claim 9, further comprising guiding the first article at the second center of motion towards the right side.
11. The method of claim 1, further comprising decelerating the first article prior to transferring the first article to the transport vehicle.
12. A mail processing system, comprising:
- an infeed line coupled to receive a first article from a feeder;
- a loading device coupled to receive the first article from the infeed line;
- a transfer unit coupled to receive the first article from the loading device; and
- a transport vehicle configured to move in proximity of the transfer unit along a first linear path, wherein the transfer unit is configured to move synchronously and parallel to the first transport unit, and wherein the transfer unit is configured to transfer the first article to the first transport vehicle.
13. The system of claim 12, wherein the loading device is configured to pivot at a first center of motion with respect to the infeed line, wherein the first center of motion is at a transition from the infeed line to the loading device, and at a second center of motion with respect to the transfer unit, wherein the second center of motion is at a transition from the loading device to the transfer unit.
14. The system of claim 13, wherein the transfer unit is configured to move back and forth along a linear path that is parallel to the first linear path.
15. The system of claim 12, wherein the infeed line extends in a direction that is substantially perpendicular to the first linear path along which the transport vehicle is configured to move.
16. The system of claim 8, wherein the infeed line and the first linear path along which the transport vehicle moves include an acute angle.
17. A loader and indexer unit for a mail processing system, the loader and indexer unit comprising:
- an infeed line coupled to receive a first article from a feeder;
- a loading device coupled to receive the first article from the infeed line; and
- a transfer unit coupled to receive the first article from the loading device, wherein the transfer unit is configured to move synchronously and parallel to a first transport unit configured to move in proximity of the transfer unit along a first linear path, and wherein the transfer unit is configured to transfer the first article to the first transport vehicle.
Type: Application
Filed: Oct 31, 2005
Publication Date: Apr 24, 2008
Applicant: SIEMENS AKTIENGESELLSCHAFT (Munich)
Inventors: Bertram Wanner (Meersburg), Rolf-Peter Skrdlant (Konstanz)
Application Number: 11/664,748
International Classification: B07C 3/06 (20060101);