Abstract:
A conveyance device comprises a sorting plate housing a plurality of roller assemblies and a series of narrow conveyor belts for conveying articles towards the sorting plate. In a first mode, the narrow conveyor belts bypass the roller assemblies and convey articles over the sorting plate. In a second mode, the conveyor belts bring an article into contact with the roller assemblies, which then manipulate the trajectory of the article.

Description:
RELATED APPLICATION 
       [0001]    The present application claims priority to U.S. Provisional Patent Application No. 62/087,453, filed Dec. 4, 2014 and entitled “Conveyor System with Roller Assemblies”, the contents of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates generally to power-driven conveyors and more particularly to conveyors having rollers for manipulating the trajectory of articles through a conveyor system. 
         [0003]    Many package- and material-handling applications require that conveyed articles be diverted to a side of a conveyor. Two examples are sorting articles off the side of a belt and registering articles against the side of the belt. U.S. Pat. No. 6,494,312, “Modular Roller-Top Conveyor Belt with Obliquely-Arranged Rollers,” Dec. 17, 2002, to Costanzo discloses a conveyor system in which cylindrical rollers mounted in a conveyor belt on axles oblique to the direction of belt travel are actuated by underlying bearing surfaces on which the oblique rollers ride as the belt advances in the direction of belt travel. The contact between the rollers and the bearing surfaces causes the rollers to rotate as the belt advances. The rotation of the oblique rollers pushes articles atop the rollers across the conveyor belt toward a side of the conveyor. These oblique-roller belts work extremely well on planar bearing surfaces as long as the rollers are arranged to rotate at an angle between the direction of belt travel (defined as a roller angle of 0°) and about 30° or so from the direction of belt travel. For roller angles greater than 30°, the rollers slip too much on the planar bearing surfaces. 
         [0004]    U.S. Pat. No. 6,968,941, “Apparatus and Methods for Conveying Objects,” Nov. 29, 2005, to Fourney describes an improved bearing surface that accommodates a much greater range of roller angles. Instead of using a planar bearing surface, Fourney uses the outer peripheries of actuating rollers arranged to rotate on axes in the direction of belt travel. As the conveyor belt advances, the oblique belt rollers roll on the underlying actuating rollers, which are also caused to roll on their axes. Because the bearing surface on the periphery is rolling, slip is reduced and greater roller angles can be accommodated. The greater roller angles permit much sharper article-diversion trajectories than are possible with a planar bearing surface. But actuating rollers are more expensive and slightly more complicated than simple planar bearing surfaces. 
         [0005]    U.S. Pat. No. 7,588,137, “Conveyor Belt Having Rollers that Displace Objects,” Sep. 15, 2009, to Fourney describes a conveyor belt that includes multiple roller sets used to divert objects from the conveyor belt. The angles along which articles can be diverted from the conveyor are limited. 
         [0006]    U.S. Patent Publication 2013/0192954, published Aug. 1, 2013 and entitled “Multi-Directional Roller Assembly” (now U.S. Pat. No. 9,978,879), the contents of which are herein incorporated by reference, describes a multi-directional roller assembly that may be driven by a conveyor belt below the assembly. The same conveyor belt conveys articles to and from a roller plate housing an array of multi-directional roller assemblies. The roller assemblies manipulate the trajectory of the articles, or pass the articles straight along the roller plate and back onto the conveyor belt. The conveyor belt is diverted below the roller plate to drive the roller assemblies. The conveyor belt may experience high tensions. Furthermore, the transition of articles off the conveyor belt, onto the roller plate and back onto the conveyor belt may alter the desired spacing between articles, in addition to presenting unnecessary instability. 
       SUMMARY OF THE INVENTION 
       [0007]    A conveyor system employs a roller plate housing an array of roller assemblies for manipulating the trajectory of an article and a series of narrow conveyor belts passing over the top of the roller plate between roller assemblies and back under the roller plate. The narrow conveyor belts are movable relative to the top surface of the roller plate. In a raised mode, the narrow conveyor belts convey articles over the roller plate. In a lowered mode, the narrow conveyor belts pass articles onto the roller plate and into contact with the roller assemblies, which manipulate the trajectory of the articles. Below the roller plate, the narrow conveyor belts in the returnway may help drive the roller assemblies. 
         [0008]    According to a first aspect, a conveyance device comprises a sorting plate having an array of roller assemblies for contacting and directing an article of conveyance along a selected trajectory, at least one conveyor belt passing between two roller assemblies and an actuator for selectively raising and lowering the conveyor belt relative to the sorting plate. 
         [0009]    According to another aspect, a conveyance device comprises a sorting plate having a plurality of rows of roller assemblies for contacting and directing an article of conveyance along a selected trajectory, a plurality of tracks passing between roller assemblies, a plurality of narrow conveyor belts contained in the tracks, and an actuator for varying the distance between the narrow conveyor belts and the roller assemblies. 
         [0010]    According to another aspect, a method of sorting articles comprises the steps of conveying articles towards a sorting plate having a plurality of roller assemblies using a series of narrow conveyor belts and adjusting a distance between the roller assemblies and the narrow conveyor belts depending on an orientation of the roller assemblies. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These aspects and features of the invention, as well as its advantages, are explained in more detail in the following description, appended claims, and accompanying drawings, in which: 
           [0012]      FIG. 1  is an isometric view of a sorting plate with a series of narrow belts passing between roller assemblies according to an embodiment of an invention; 
           [0013]      FIG. 2  is a schematic side view of a conveying system including a sorting plate, narrow belts and secondary drive belt below the sorting plate; 
           [0014]      FIG. 3A  is a side view of a sorting plate with narrow belts in a raised mode according to an embodiment of the invention; 
           [0015]      FIG. 3B  is a side view of a sorting plate with narrow belts in a lowered mode according to an embodiment of the invention; 
           [0016]      FIG. 4A  is an isometric view of a rotational ramp for positioning a narrow belt in a first position; 
           [0017]      FIG. 4B  is an isometric view of a rotational ramp for positioning a narrow belt in a second position; and 
           [0018]      FIG. 5  is a schematic view of a portion of a roller plate including a narrow belt passing between roller assemblies and having ramps on a rack gear for selectively raising and lowering the narrow belt according to another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    A conveyor system includes an array of roller assemblies and a plurality of narrow conveyor belts passing over the roller plate between the roller assemblies. The invention will be described below relative to certain illustrative embodiments, though one skilled in the art will recognize that the invention is not limited to the illustrative embodiments. 
         [0020]      FIG. 1  shows a conveyor system including a sorting plate  10  that comprises a plurality of roller assemblies  20  for selectively changing the trajectory of a conveyed article. The roller assemblies  20  are arranged in a pattern of alternating rows, though the sorting plate  10  may have any suitable number, size, configuration and arrangement of roller assemblies. The roller assemblies  20  are housed between upper and lower plates, as described in U.S. Patent Publication 2013/0192954, published Aug. 1, 2013 and entitled “Multi-Directional Roller Assembly”, the contents of which are incorporated herein by reference, though the invention is not limited to the multi-directional roller assemblies there described. 
         [0021]    The sorting plate  10  includes a plurality of narrow conveyor belts  50 . The belts  50  operate in at least two modes: a raised mode and a lowered mode. In one embodiment, an actuator selectively raises or lowers the drive belts relative to the sorting plate  10  to switch between modes. In a raised mode, one or more of the drive belts is raised above the top surface of the sorting plate  10 , so that a product carried towards the sorting plate by the drive belts will pass over the sorting plate without contact with the roller assemblies  20 . In the raised mode, the belts  50  serve as the primary conveyor of articles over the sorting plate  10 . In a lowered mode, an actuator lowers the conveyor belts  50  relative to the top surface of the sorting plate, so that an article conveyed to the sorting plate  10  by the belts  50  contacts the roller assemblies  20  which then direct the article in a selected direction, depending on the orientation of the roller assemblies. In one embodiment, the belts  50  return under the sorting plates and also serve as drivers for the roller assemblies  20 . As show, the narrow conveyor belts  50  have a width sufficiently narrow to allow passage of the conveyor belt between adjacent roller assemblies  20  in the sorting plate  10 . 
         [0022]    The individual roller assemblies  20  are arranged to allow clear passage of the narrow belts in either situation in either mode. The roller plate  10  may include tracks between different roller assemblies for containing the belts  50 . The tracks keep the belts in a straight orientation relative to the motion and support the weight of the belts and conveyed articles. In one embodiment, an actuator selectively moves the tracks up and down to expose the conveyed articles to the roller assemblies  20 . In another embodiment, the conveyor belts  50  can remain vertically stationary while the roller assemblies  20  move up and down to alternate between the two modes. 
         [0023]    In one embodiment, the actuator moves only the top (carryway) portion of the belts  50  between raised and lowered positions. In another embodiment, the actuator moves an entire belt  50  or series of belts  50 , or the roller plate  10  may be moved relative to the top portion of the belts  50 . The tracks or the belts  50  or the roller assemblies  20  or the roller plate  10  may be raised and lowered independently of the actual roller assemblies using cams, motors, air cylinders, hydraulic cylinders, magnets, springs or any suitable combination of actuators. 
         [0024]      FIG. 2  is a schematic side view of the conveying system of  FIG. 1 . The narrow belts  50  convey an article  60  towards the sorting plate  10 . In a raised mode, the narrow belts  50  convey the article at belt speed over the sorting plate  10 . In a lowered mode, the narrow belts  50  convey the article to the sorting surface of the sorting plate  10 , where the roller assemblies act on the package. The narrow belts  50  return below the sorting plate  10 . The narrow belts may engage a secondary belt  70  below the sorting plate  10  to drive the roller assemblies  20 . Alternatively, a motor or other suitable driver may be used to drive the roller assemblies  20 . 
         [0025]      FIG. 3A  is a side view of the sorting plate  10  with the narrow belts  50  raised relative to the top surface of the roller plate  10 . In a raised mode, the top surface of the narrow belts  50  remains the conveying surface for conveyed articles. The conveyed article does not contact the roller assemblies as it passes over the sorting plate  10 . 
         [0026]      FIG. 3B  is a side view of the sorting plate  10  with the narrow belts  50  lowered relative to the top surface of the sorting plate  10 . In the lowered mode, the top surface of the belts  50  is even with or below the tops of the roller assemblies, so that the roller assemblies  20  contact the conveyed article. Each roller assembly  20  is selectively oriented and actuated to manipulate the trajectory of a conveyed article. 
         [0027]    Any suitable means for raising and lowering the belts  50  may be used. In one embodiment, the vertical motion of the belt  50  over the roller plate  10  may be connected to the orientation of the roller assemblies  20  within the plate. 
         [0028]    For example,  FIGS. 4A and 4B  show a rotational ramp  90  for guiding and changing the height of a belt  50  across a roller plate  10 . The rotational ramp  90  forms a track  91  with walls  92  for guiding a narrow conveyor belt over or through a roller plate. The rotational ramp  90  is designed so that the track  91  is in a high position ( FIG. 4A ) when the roller assemblies are in a pass-through position, so that the roller assemblies do not contact the conveyed article. When the roller assemblies are oriented in a sorting orientation, the track  91  is in a lower position ( FIG. 4B ) to lower the conveyor belt  50  passing through the track  91 , allowing an article conveyed by the conveyor belt  50  to contact the roller assemblies. The rotational ramp comprises a top portion  95 , which is fixed to the narrow belt track and a bottom portion  96 , which rotates with the roller assemblies or connected gearing. The bottom portion and top portion including bearing surfaces, such that rotation of the bottom portion  96  relative to the top portion  95  pushes the top portion  95  up to raise the track  91 . 
         [0029]      FIG. 5  is a schematic overhead view of a belt  50  passing through a pair of roller assemblies  20  according to another embodiment of the invention. In the embodiment of  FIG. 5 , each roller assembly  20  includes peripheral teeth  22  that engage a rack gear  24  or other actuator to selectively orient the roller assemblies  20 . The rack  24  includes ramps  26  for selectively raising and lowering the belt  50  relative to the roller assemblies  20 , depending on the orientation of the roller assemblies. When the roller assemblies are oriented in a pass-through orientation, the ramps  26  move inwards to push the belt  50  up so that the roller assemblies do not contact the conveyed article. When the rollers assemblies  20  are oriented in a sorting orientation, the ramps  26  pull away from the belt to lower the belt  50 . 
         [0030]    Both the rotational ramp  90  shown in  FIGS. 4A and 4B  and the linear ramp  26  mechanisms can serve the dual purpose of transferring motion from one roller assembly  20  to another while also raising and lowering the belt  50  or a track containing the belt. 
         [0031]    The narrow conveyor belts  50  allow a continuous conveying surface to be maintained. Since the belts  50  follow a much straighter path, the belt tension, belt wear and consumed power is reduced. 
         [0032]    As these few examples suggest, the scope of the invention is meant to be defined by the claims and not limited to the details of the described versions.