Abstract:
A sorting conveyor employs suction to stabilize products on a conveyor belt. The sorting conveyor comprises a conveyor belt including a plurality of embedded rollers for moving conveyed objects relative to the conveyor belt. A vacuum chamber below the conveyor belt houses activators for the rollers and selectively creates a vacuum zone above the conveyor belt for pulling objects on the conveyor belt.

Description:
BACKGROUND 
     The invention relates generally to power-driven conveyors and, more particularly, to a conveyor that employs a vacuum to facilitate conveyance. 
     Conveyor belts may sometimes include article-supporting rollers to propel conveyed objects in a desired direction as the conveyor belt advances. Conveyor belts with article-supporting rollers may be used for accelerating, diverting, sorting, merging, switching or otherwise moving objects in a selected direction relative to a moving conveyor belt. The rollers are arranged to rotate in line with or perpendicular or oblique to the direction of belt travel. Examples of conveyors using belts of this kind are described in, for example, U.S. Pat. Nos. 6,494,312; 6,968,941; 7,461,739; and 7,971,701. 
     Conveyed objects may be unsteady on conveyor belts, particularly due to the use of embedded rollers, which may cause the objects to shift or fall. 
     SUMMARY 
     A sorting conveyor employs suction to stabilize products on a conveyor belt employing article-supporting rollers. The sorting conveyor includes at least one vacuum chamber housing activators for the rollers in the conveyor belt. Each vacuum chamber is coupled to a vacuum generator, which selectively generates a vacuum in the associated vacuum chamber to pull articles being conveyed against the conveyor belt. A control system may be used to selectively operate a selected vacuum generator when a product is in an associated vacuum zone. 
     According to one aspect, a sorting conveyor comprises a conveyor belt having a plurality of rollers, a vacuum chamber disposed below the conveyor belt, the vacuum chamber connected to a vacuum generator to create a vacuum zone in a select area above the conveyor belt and a controller for selectively operating the vacuum generator when a conveyed object is in the vacuum zone. 
     In another aspect, a sorting conveyor comprises an array of vacuum chambers, each vacuum chamber connected to a vacuum generator, an array of activators for selectively activating one or more rollers in a conveyor belt, each vacuum chamber housing a set of activators and a conveyor belt traveling over the series of vacuum chambers. The conveyor belt comprises a plurality of rollers, with at least one roller in contact with an activator. 
     According to another aspect, a method of conveying objects using a conveyor comprises the steps of conveying an object on a conveyor belt through a plurality of vacuum zones, the conveyor belt comprising an array of rollers, and generating a vacuum in a selected vacuum zone when the object enters the selected vacuum zone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed systems and methods can be understood with reference to the following drawings. The components in the drawings are not necessarily to scale. 
         FIG. 1  is a perspective view of a section of a sorting conveyor employing a vacuum according to an illustrative embodiment of the invention; 
         FIG. 2  is a detailed, cross-sectional view of an actuator and conveyor belt module of the sorting conveyor of  FIG. 1 ; and 
         FIG. 3  is a block diagram showing the relationship between a sensor, tracker, vacuum generator and controller for the vacuum generator according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A sorting conveyor employs the use of a vacuum to stabilize conveyed objects. The invention will be described below relative to certain illustrative embodiments, though the invention is not limited to the illustrative embodiments. 
       FIG. 1  illustrates a sorting conveyor  10  according to an illustrative embodiment of the invention. The sorting conveyor  10  comprises a conveyor belt  102  traveling in a travel direction indicated by arrow  12 . The conveyor belt includes embedded rollers  118 , which are longitudinally oriented in the illustrative embodiment. The conveyor belt may comprise a plurality of conveyor belt modules  106  hingedly connected together. An array of activators, illustrated as field  104  of angularly adjustable drive roller modules  108  is disposed below the conveyor belt a sorting region. Each roller module  108  may comprise a free-spinning drive roller  125  mounted in a cartridge  130 . The cartridge  130  may include teeth  136 , shown in  FIG. 2 , used to orient the activator. The conveyor belt and activators may be same or similar to the system described in U.S. Pat. No. 7,971,701, the contents of which are incorporated herein by reference. 
     The activators  108  may be selectively oriented and actuated to move product in a selected direction, indicated by arrows  112   a ,  112   b  and  112   c , relative to the conveyor belt. 
     Each module includes spaces  109  between the rollers  118  and the module body  106 . The module may include other openings extending from the top surface of the module to the bottom surface, as well. 
     The array of activators  104  may include spaces  141  between the cartridges  108  and spaces  142  between the cartridges  130  and driver rollers  125 . 
     The sorting conveyor  10  employs a vacuum to stabilize conveyed articles on the conveyor belt  102 . In one embodiment, the sorting conveyor  10  includes one or more vacuum chambers  200  housing the activators  104  and arranged in series. Each vacuum chamber is a sealed box comprising side walls  201  and an open top. A set of activators  104  is housed within the side walls  201  of each vacuum chamber  200 . The conveyor belt  102  rides over the open tops of the vacuum chambers. Each vacuum chamber further includes a connector  204  in a side wall for connecting the vacuum chamber  200  to a vacuum generator. A vacuum generator (not shown) is connected to each vacuum chamber  200  to create a vacuum zone above each vacuum chamber. Each vacuum zone may be segregated from the other vacuum zones. 
     The vacuum generated by the vacuum generator may pull articles being conveyed against the belt  102  to provide stability. The vacuum may be applied to the conveyed articles during straight conveyance, switching, sorting, and-or transitions on and off of the conveyor belt  102 . 
     In one embodiment, the vacuum is a continuous air flow. In another embodiment, the vacuum may be controlled in different regions. For example, each vacuum chamber may be selectively actuated to create a vacuum in a selected vacuum zone. 
     Referring to  FIG. 3 , to perform selective actuation of a vacuum zone, the sorting conveyor  10  may include a sensor  230  for sensing of an article of conveyance. The sensor  230  may be a photoelectric sensor or any other suitable sensor known in the art. The sensor may sense the initial positioning of the product. A tracker  240 , such as an encoder, may track the location of the conveyed article along the conveying surface. 
     Information from the sensor  230  and tracker  240  is fed to a controller  250  for a vacuum generator  260 . Based on the information, the controller may selectively activate a vacuum generator for each vacuum zone. The vacuum generator may generate a vacuum only when a conveyed object is in the vacuum zone and turn the vacuum off when the article exits the vacuum zone. The selective operation of the vacuum conserves energy and resources. 
     Alternatively, the controller  250  may use information regarding the location of a conveyed object to selectively connect a vacuum chamber  200  to a vacuum generator when it is desirable to create a vacuum in the vacuum zone above the vacuum chamber, and disconnect the vacuum chamber from the vacuum generator when suction is not necessary or desirable in the vacuum zone.