Conveyor system with diverting track network

Details Conveyor system with diverting track network Conveyor system with diverting track network

2000-06-29

2003-02-04

Dayoan, D. Glenn (Department: 3612)

Conveyors: power-driven

Conveyor arrangement for selecting among plural sources or...

By loading or unloading section at selected one of a...

C198S412000, C198S415000

Reexamination Certificate

active

06513642

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates generally to conveyor diverting systems, and, more particularly, to conveyor diverting systems having an endless conveying surface composed of multiple surface members, each one or group of adjacent ones mounted with a laterally movable shoe capable of diverting articles from the conveyor by pushing laterally against the articles as they move down the conveyor. Such lateral pushing thereby diverts a package, such as from the main conveyor to an adjacent branch conveyor, or other receiving structure.
Conveyor diverting systems using a moving conveying surface consisting of a plurality of parallel surface members, the conveying surface being propelled, such as by being mounted to endless chains, have been known for a number of years. Such diverting systems utilize a diverter shoe movably mounted on one or more surface members for lateral movement with respect to the conveying surface under the guidance of a track network. The track network is located generally under the conveying surface and guides the diverter shoes via pins descending from the diverter shoes and engaging the track network. Diverters in the track network selectively transfer guidance of each diverter shoe from a track running in the direction of the movement of the conveying surface to a diagonal track, or plurality of diagonal tracks, in order to cause lateral movement of the diverter shoes. An example of a diverting gate used to selectively transfer guidance of diverter shoes between tracks is disclosed in U.S. Pat. No. 5,409,095, issued to Hoshi et al., and U.S. Pat. No. 5,039,912, issued to Cotter. In order to avoid wasted spacing between variable-length packages, such diverting systems may include manual or automatic measuring means at an infeed point to cause the diverter gate associated with the selected branch conveyor to divert a selected number of shoes corresponding in general to the length of the package. Exemplary of this type of conveyor are U.S. Pat. No. 3,361,247, issued to James N. Lauzon et al. and U.S. Pat. No. 4,738,347, issued to Brouwer, and commonly assigned with the present invention.
With increased demands for the number of packages to be conveyed by such conveying systems, the inter-package spacing distance has become a critical factor in the design of conveying systems. Decreasing the spacing between packages on the conveyor allows a greater throughput of packages by the conveyor. Conversely, providing more space between the packages results in a diminished efficiency and throughput.
A specific minimum inter-package spacing is required in this system as a result of the rotation of the diverted package as it is initially diverted. Because of this rotation, additional inter-package spacing is required to avoid conflict between the diverting package and a closely trailing package. This rotation pushes the trailing corner of the package adjacent the branch conveyor back a distance, which can be estimated using the width (W) of the package and the acute angle (&thgr;) which is formed by the intersection of the material flow on the main conveyor and the diverter shoe diagonal guide track. Using these two variables and assuming that the package rotates about the trailing corner opposite the branch conveyors, it will be observed that:
A=W
sin &thgr;
where A is the distance the trailing corner adjacent the branch conveyor is pushed back by the package's rotation. It is, therefore, necessary with this system that packages to be diverted are not spaced closer together than the distance W sin &thgr;.
By way of example, if a diverting branch is oriented at about 20° with packages 16 inches in width, an inter package distance of approximately 5.5 inches is necessary. If the package is 24 inches long, this results in the need for approximately 23% more empty space on the conveyor. A hypothetical system that could divert packages without any significant space between packages could thus produce a 23% increase in package throughput without any increase in conveyor speed. The high desirability of such a system is thus clear.
Prior methods of diverting packages that addresses the problem of reducing the required inter-package spacing, is described in commonly assigned U.S. Pat. No. 5,165,515, issued to Michael L. Nitschke et al., which is commonly assigned with the present application. This system increases throughput by not rotating the diverted packages. This non-rotation is accomplished by using a plurality of generally parallel diverting tracks oriented diagonally with respect to the direction of conveyor movement, instead of a single diverting track. Each track has its own diverting gate which is actuated to divert the movement of the diverting shoes from the direction of the conveyor to the lateral diverting direction. By simultaneously activating more than a single diverting gate, a group of diverting shoes corresponding to the measured package length can be moved laterally across the conveyor surface. This group of shoes acts along nearly the entire length of the package to be diverted and, therefore, causes no rotation of the package. Without rotation of the package, the inter-package spacing requirement is reduced to a minimum.
However, this technique is not without difficulties. The deliberate non-rotation of the packages means the packages will enter the branch conveyor still aligned parallel to the main conveyor, but oriented generally diagonally with respect to the branch conveyor (i.e., their lengthwise sides are not parallel to the direction of motion of the branch conveyor). This orientation significantly increases the necessary width of the branch conveyors, resulting in an increase in cost and a reduction in the spacing on branch conveyors.
Still another method of diverting packages which reduces the required inter-package spacing, is described in commonly assigned U.S. Pat. No. 5,927,465, issued to Shearer, Jr. With this system, an automatic controller oversees the operation of the diverting gates to determine which diverting gates are to be actuated and for how long, depending upon the measured length of the packages on the conveyor. Once the length of the package is determined, the controller determines whether a package will be diverted using one diverting gate or two (or more) diverting gates. For certain situations, such as long packages, a single diverter is activated and as many diverting shoes are diverted as necessary to divert the package through the single diverting gate. Packages diverted in this manner are rotated, with the trailing corner of the package moving in an initial rearward direction.
Other packages are diverted with two or more gates in a manner that the packages are initially diverted out of line with other packages without substantially rotating the packages, in the same manner as in Nitschke et al. '515 Patent. After the initial diverting, the package is then rotated prior to discharge to the spur. This has the advantage of the Nitschke et al. '515 Patent of not requiring increased gaps between packages but eliminates the disadvantage of increased spur size. However, some of the packages, such as long packages, are still diverted using conventional techniques and increased gaps must be provided at both ends of such packages.
It will thus be observed that there exists a need for a conveyor diverting system that can divert packages with little or no inter-package spacing, and ensure that packages diverted to the branch conveyor are properly aligned, all while keeping costs to a minimum.
SUMMARY OF THE INVENTION
The present invention provides a sortation conveyor which achieves efficiency gains through reduction of the inter-package spacing. These efficiency gains are especially desirable because they can be achieved without the extra power consumption, noise, and wear that results from increasing the conveyor speed. The present invention increases conveyor diverting system throughput by utilizing a diverting track network having at least one downstream diverting track and a plurality o

Affiliated with

Also associated with

Rating

Conveyor system with diverting track network does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Conveyor system with diverting track network, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conveyor system with diverting track network will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3123105