Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Condition responsive means controls separating means
Reexamination Certificate
1999-11-15
2001-07-24
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Condition responsive means controls separating means
C209S552000, C209S509000, C198S890000, C198S890100, C198S570000, C198S571000, C198S572000, C198S575000, C198S577000, C198S597000
Reexamination Certificate
active
06264042
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to sorting systems, and more particularly to a bilateral sorting device and method for sorting objects that selectively diverts the objects off a main conveyor path to one or more secondary conveyor paths.
BACKGROUND OF THE INVENTION
Automated sorting of parcels is becoriing widespread because it reduces labor costs while enabling fast and reliable parcel delivery services. However, many conventional automated parcel sorting systems require extensive hardware and computer controls to accurately track and move objects along predefined paths. Further, such automated parcel sorting systems often occupy a large amount of space.
With many moving parts and logic devices, conventional automated parcel sorting systems may be prone to break down and result in costly down time. Additionally, a large number of parts and logical devices can make a system more difficult to repair, replace, and maintain. If expensive parts are replaced to save down time, rather that repaired, the cost of operating the system increases.
Some automatic sorting systems operate on the principal of pushing objects off a conveyor using a suspended paddle or the like. These systems may have difficulty in consistently diverting thin items, such as letters, which may pass or jam under the suspended paddle. Other systems have a complex system of transverse belts that are lifted from between driven rollers to divert objects from an initial path. Generally, the raised area defined by the lifted belts must be comparable in length to the object being diverted.
When a sorting system must divert objects of diverse size, other problems may arise. In a parcel sorting system, for example, a fast moving paddle in a high speed sorting system might effectively divert parcels of medium size and weight, but send very light parcels flying and possibly damage heavy parcels on impact If a parcel has an unusually positioned center of gravity, the paddle may tumble or spin the parcel in an uncontrolled manner. Furthermore, heavy parcels are difficult to divert accurately while the conveyor line is moving at full speed, which may be several hundred feet per minute. Many prior systems slow or stop the main conveyor line while an object is being diverted off the line.
Accordingly, there is a need in the art for an automated parcel sorting system that has a reduced number of parts and expensive electromechanical elements, that occupies less space, and that can divert thin items consistently. There is a further need in the art for a sorting system that can adapt to effectively and safely divert a sequence of objects that vary widely in size, shape, weight, and center of gravity, while the main conveyor is moving at a high speed. A further need exists in the art for increasing the sorting rate of objects in such systems.
SUMMARY OF THE INVENTION
The present invention seeks to provide an automated parcel sorting system with a small number of parts and electromechanical elements, that occupies less space, that can divert thin items consistently, and that adapts to divert at a high sorting rate a sequence of objects that vary widely in size, shape, weight, and center of gravity.
These objects are achieved in the present invention by a system for sorting objects, comprising: an upstream and a downstream conveyor positioned to sequentially receive and convey an object along a first path, the conveyors defining a gap transverse to the first path; an elongate sorting member positioned in the transverse gap; a diverter movable to intersect the object moving along the first path; and an actuator connected selectively to move the diverter to shift the object off the conveyors, and selectively to allow the object to pass over the gap without being diverted.
In one aspect of the invention, the elongate member including a generally planar portion sloping upwardly from the upstream conveyor across the gap toward the downstream conveyor, such that a leading portion of the object is raised above the upstream conveyor as the object crosses the gap. This raising action substantially reduces the friction between object and the conveyors as the object is pushed off the conveyors. The downstream conveyor may be positioned higher than the upstream conveyor. Preferably, the elongate member is movable transversely with respect to the gap, and the diverter comprises upwardly projecting cleats movable with the elongate member, the cleats being placed in a section of the elongate member adjacent to the generally planar portion.
According to another aspect of the invention, a measuring device is positioned to determine a transverse position on the upstream conveyor of a side edge of the object opposite a side of the conveyor to which the object is to be diverted; and the sorting member includes at least one projection extending upwardly from the cairier strip; the actuator being connected selectively to move the projection adjacent to the path of the side edge of the object prior to the object reaching the sorting member. The actuator preferably comprises a controller configured to move the sorting member in response to a signal from the measuring device indicating an approaching object. The controller preferably receives from the measuring device the transverse position on the upstream conveyor of the side edge of the object opposite the selected side of the conveyor to which the object is to be diverted, and causes the actuator to position the diverter section of the sorting member adjacent to the path of the side edge of the object prior to the object reaching the sorting member. The controller preferably further receives from the measuring device longitudinal positions of the leading and trailing edges of the object, and causes the actuator to move the projections against and under the object at a selected location along its length.
According to another aspect of the invention, the elongate member is a sorting member including an elongate carrier strip defining at least one diverter section comprising a plurality of flexible, spaced apart projections extending upwardly from the carrier strip, and at least one generally planar section adjacent to the diverter section. The actuator is connected selectively to move the projections against and under an object travelling across the sorting member to carry the object off the conveyors, and selectively to position the planar section in the path of an object to allow the object to pass over the sorting member without being diverted.
In each of these aspects of the invention, the sorting member or device may preferably be an endless flexible belt carrying a plurality of groups of flexible cleats inter-spaced with non-cleated sections of the belt The belt may be reversibly driven transversely to the first direction so that the system provides three destinations for each object, two side diversion paths and a straight pass-through path. Alternatively, the sorting member may be a reciprocating linear strip or slat In either case, the belt or strip may have a width in the first direction considerably less than the length of the objects being sorted.
A bilateral sorter and a method for sorting an object according to a preferred embodiment of the present invention can increase sorting rate by measuring the dimensions of the object and calculating an approximate maximum acceleration and velocity at which an object can be moved without tipping or rotating. The bilateral sorter substantially reduces or eliminate tipping or rotating of an object by pre-positioning the sorting member in accordance with an object's dimensions. Additionally, the present invention employs a sorting member that can substantially reduce the static friction between the object and neighboring conveying devices.
The present invention may be considered in relation to a system for sorting objects, employing a conveyor device for moving an object along a first path. The sorting system further includes a sorting device for moving the object along a sort direction. The sorting device has structures for lifting an
Cossey, Jr. James R.
Prutu Victor N.
Tew Richard J.
Alston & Bird LLP
Beauchaine Mark J.
United Parcel Service of America Inc.
Walsh Donald P.
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