Abstract
An arrangement for separating overlapping parcels on a conveyor system is disclosed. It utilizes a series of rollers, each comprising multiple independently driven bands, to create a speed gradient across the conveyor width. This differential speed causes parcels that are in contact or partially overlapped to separate and align, enabling subsequent processing such as scanning or sorting. The system includes mechanisms for detecting parcel width and overlap, diverting un-singulatable parcels, and recirculating parcels for another attempt at singulation, thereby improving throughput and reducing manual intervention.
1. Technical Field
[0001]This disclosure relates to the field of material handling, specifically to systems and methods for singulating discrete items, such as parcels or packages, on a conveyor system.
2. Technical Context
[0002]In automated material handling systems, parcels often arrive at processing stations, such as barcode scanners or sortation gates, in an overlapped or side-by-side configuration. This condition prevents individual parcels from being correctly identified or diverted, leading to system inefficiencies, mis-sorts, or stoppages. Current solutions may involve manual intervention, which is costly and slow, or simple gapping systems that are ineffective against significant overlaps or side-by-side presentations. A need exists for a system that can reliably separate such items into a single file with sufficient gaps for automated processing.
3. System Overview
[0003]The disclosed system employs a series of singulation rollers (10) arranged in a conveying section, each roller composed of multiple independently driven bands (12). These bands (12) are controlled to establish a speed gradient across the width of the conveyor. As parcels (20) enter this section, any overlapping or side-by-side parcels (20) are subjected to different tangential forces across their contact points with the bands (12), causing them to rotate, separate, and align. Sensors (22) upstream and within the singulation zone detect parcel presence, width, and potential overlap. A control system (24) manages the band speeds and monitors sensor inputs. Parcels (20) that are successfully singulated continue downstream. Parcels (20) that remain overlapped or are too wide to be singulated are diverted to a recirculation path (26) for another attempt.
4. Components
[0004]The singulation system comprises several key components, as illustrated in FIG. 1 and FIG. 2:
[0005]
- Singulation Rollers (10): These are the primary conveying elements within the singulation zone. Each roller (10) is typically cylindrical and extends across the width of the conveyor.
- Roller Bands (12): Each singulation roller (10) is segmented into multiple individual bands (12). These bands (12) are independently driven or can be grouped into zones with distinct speeds. The bands (12) are typically constructed from a durable material with a high coefficient of friction, such as rubber or urethane.
- Drive Motors (14): Individual or small groups of roller bands (12) are powered by dedicated drive motors (14). These motors (14) are typically servomotors or variable-speed DC motors, allowing precise control of each band's tangential velocity.
- Conveyor Frame (16): A structural frame supports the singulation rollers (10), drive motors (14), and associated components, maintaining their alignment and position.
- Parcel Sensors (22): These include arrays of photoelectric sensors, laser scanners, or vision systems positioned upstream of and within the singulation zone. They detect parcel (20) presence, measure length, width, and position, and identify potential overlap conditions. A sensor array (22a) at the entrance detects overall parcel dimensions, while a downstream array (22b) verifies singulation success.
- Control System (24): A programmable logic controller (PLC) or industrial PC that receives data from the parcel sensors (22), calculates required band speeds, and sends commands to the drive motors (14). It also manages the diversion of un-singulatable parcels (20).
- Diverter Mechanism (28): A pneumatic push-arm, pop-up wheel sorter, or similar device located at the end of the singulation zone. It redirects parcels (20) that fail to singulate or are too wide onto a recirculation conveyor (26).
- Recirculation Conveyor (26): A conveyor path that returns diverted parcels (20) to the entrance of the singulation system for another processing attempt.
- Side Guides (30): Adjustable side guides (30) along the singulation zone help to maintain parcel (20) alignment and prevent packages from falling off the conveyor, as shown in FIG. 3.
5. Operation
[0006]The singulation process proceeds through several stages:
[0007]Start-up: Upon system activation, the control system (24) initializes all drive motors (14) and sensors (22). The roller bands (12) begin rotating at their default or pre-programmed speeds, establishing an initial speed gradient across the singulation zone.
[0008]Steady Running:
[0009]
- Parcel Entry and Detection: Parcels (20) arrive from an upstream conveyor and enter the singulation zone. An initial sensor array (22a) at the entrance measures the width and length of incoming parcels (20) and identifies potential overlap or side-by-side conditions.
- Speed Gradient Application: Based on the detected parcel (20) characteristics, the control system (24) adjusts the speeds of the individual roller bands (12). Typically, the bands (12) on one side of the conveyor operate at a higher tangential velocity than those on the opposite side. For example, bands (12) may range from 1.0 m/s to 2.0 m/s across the conveyor width. This creates a shear force on any parcel (20) spanning multiple bands (12) with different speeds. If two parcels (20) are overlapped, the parcel (20) contacting the faster bands (12) will accelerate relative to the parcel (20) on the slower bands (12), causing them to separate and rotate until they align with the general direction of flow and are no longer overlapped.
- Gap Measurement and Verification: As parcels (20) move through the singulation zone, a downstream sensor array (22b) continuously monitors their position and separation. The gap between successive parcels (20) is measured to ensure it meets a minimum threshold, for example, 150 mm. The width of each singulated parcel (20) is also verified against system limits.
- Successful Singulation: Parcels (20) that are successfully singulated, aligned, and have adequate gaps continue downstream for further processing, such as scanning or sortation.
[0010]Fault or Interruption:
[0011]
- Un-singulatable Parcels: If the downstream sensor array (22b) detects parcels (20) that remain overlapped, are too wide for the downstream path (e.g., exceeding 600 mm), or are otherwise not correctly singulated after traversing the zone, the control system (24) activates the diverter mechanism (28). These parcels (20) are directed onto the recirculation conveyor (26).
- System Jam: In the event of a parcel (20) jam within the singulation zone, detected by prolonged sensor (22) blockage or motor (14) overload, the control system (24) will stop the affected rollers (10) and signal an alarm, awaiting operator intervention.
- Recirculation: Parcels (20) on the recirculation conveyor (26) are returned to the infeed of the singulation zone, allowing them another attempt at being singulated. This process can be repeated a predetermined number of times before a parcel (20) is flagged for manual handling.
6. Example Embodiments
[0012]Embodiment 1 In this embodiment, each singulation roller (10) is divided into five distinct bands (12), with each band (12) driven by an individual servomotor (14). The speeds of these bands (12) are set to create a linear speed gradient across the conveyor width. For instance, the leftmost band (12) operates at 1.0 m/s, the next at 1.25 m/s, the middle at 1.5 m/s, the next at 1.75 m/s, and the rightmost at 2.0 m/s. This fixed gradient is applied to all parcels (20) entering the zone. Parcel detection is performed by a single array of diffuse photoelectric sensors (22) at the entry, which triggers the zone operation.
[0013]Embodiment 2 This embodiment features singulation rollers (10) where each roller (10) consists of ten narrower bands (12). These bands (12) are grouped into three zones: an inner zone of four bands (12) and two outer zones of three bands (12) each. Each zone is driven by a separate motor (14). The control system (24) dynamically adjusts the speed of each zone based on real-time data from a vision system (22) that provides precise parcel (20) dimensions and overlap percentages. For instance, if a significant overlap is detected towards the left, the leftmost zone's speed can be temporarily increased more aggressively relative to the center and right zones to induce a stronger separation force.
[0014]Embodiment 3 This embodiment integrates the singulation system with a pre-sortation buffer. Parcels (20) enter a short accumulation section before the singulation rollers (10). A series of induction sensors (22) measure the gap and position of parcels (20) in the buffer. The control system (24) then pre-selects the optimal speed profile for the singulation rollers (10) based on the anticipated parcel (20) configuration from the buffer. This predictive approach allows for a more optimized application of differential speeds, reducing the need for multiple recirculation attempts. The recirculation path (26) in this embodiment includes a small manual inspection station for parcels (20) that fail singulation after two attempts.
7. Alternative Configurations
[0015]The drive system for the roller bands (12) could alternatively employ a common drive shaft with clutches for individual bands (12), allowing for selective engagement and speed variation through geared ratios or friction drives. Instead of a linear speed gradient, a non-linear or stepped speed profile could be implemented across the bands (12) to suit specific parcel (20) characteristics or desired separation dynamics. The roller surface material could feature specific patterns or textures to enhance grip on certain parcel (20) packaging types. The diverter mechanism (28) could be a series of retractable wheels that lift and guide parcels (20) onto the recirculation path (26).
8. Parameter Variations
| Parameter | Range | Effect of Increasing Value | Effect of Decreasing Value |
|---|---|---|---|
| Roller Band Speed Differential | 0.5 to 1.5 m/s | Stronger shear forces, faster separation, potential for parcel instability. | Weaker shear forces, slower separation, reduced singulation effectiveness. |
| Number of Roller Bands | 3 to 15 per roller | Finer control over speed gradient, better adaptation to parcel width. | Coarser speed steps, less precise control, potential for less effective singulation. |
| Singulation Zone Length | 1.5 to 4.0 meters | More time for parcels to singulate, higher success rate. | Less time for separation, lower success rate, more recirculation. |
| Parcel Recirculation Limit | 1 to 5 attempts | Higher probability of eventual singulation, increased system load. | Faster rejection of un-singulatable items, lower system load. |
| Minimum Parcel Gap | 100 to 300 mm | More space for downstream processing, lower throughput. | Less space for downstream processing, higher throughput, increased risk of read errors. |
9. Additional Implementations
[0017]The differential speed roller band concept can be adapted for other applications requiring precise item separation. For instance, it could be implemented in baggage handling systems to singulate luggage items entering X-ray machines. Another application is in manufacturing lines for separating irregularly shaped components on a production line before assembly or quality inspection. Furthermore, the system could be integrated with advanced robotics, where the singulated parcels (20) are then picked by a robotic arm, requiring precise positioning. The detection system (22) could incorporate machine learning algorithms to predict optimal speed profiles based on historical data of parcel (20) interactions, further enhancing singulation efficiency.
10. Figures
