Abstract:
A conveyor system is provided to limit the vertical fall experienced by a product transported along the conveyor and falling into a collection bin. A sensor in a fixed position relative to the product conveying plane of the conveyor measures product collection height in a collection bin to produce an output signal. A controller dynamically varies the angle between the conveyance plane and the collection bin base plane and the vertical displacement therebetween within a preselected range in order to minimize product damage associated with different fall trajectories from the conveyor into the bin for product. Either the conveyor or the collection bin is pivoted under the command of the controller to accomplish the desired function.

Description:
FIELD OF THE INVENTION 
     The present invention relates in general to a conveyor system and in particular to a conveyor system having a sensor, the readings of which are used to moderate the fall of a product from the conveyor to a collection bin or secondary conveyor. 
     BACKGROUND OF THE INVENTION 
     A common source of product damage is found in products being conveyed falling off a conveyor belt and falling into a collection bin. The first products conveyed into a bin experience the longest trajectory and impact with bin surfaces. This product, and subsequently conveyed products, then experience repeated subsequent impacts as other products continue to fill the bin. Additionally, as products are collected in a bin, the products tend to mound about the average trajectory of a product from the conveyor into the bin. This mounding affords inefficient and unbalanced fill of the bin that results in still further product damage associated with the collapse of the unstable mound, agitation to redistribute product within the bin, or mechanical raking. Products such as agricultural produce and various manufactured goods having coatings susceptible to chipping or abrasion, such as painted mechanical fasteners, are representative of the goods that suffer damage upon collection. The prevention of binning damage associated with product collection would have the effect of reducing the amount of operator control with such a conveyor system and reduce product defects. 
     Thus, there exists a need for a conveyor system capable of moderating the impact experienced by a product falling from a conveyor into a collection bin. 
     SUMMARY OF THE INVENTION 
     A conveyor system includes a conveyor having a first end and a second end as well as a conveyance surface. The conveyor ends and the conveyance surface together define a conveyance plane on which a product is transported. A product transported on the conveyor falls from an end into a collection bin. The collection bin has a base and typically, product retaining sidewalls. The collection bin base defines a collection plane that is vertically displaced below the conveyance plane. A collection angle measured from the first end of the conveyor through the vertical displacement is also defined. A pivot mechanism is provided for varying the collection angle and the vertical displacement between the conveyor end and the base of the collection bin. A sensor monitors product collection height and produces an output signal corresponding to the product collection height. A controller activates the pivot mechanism to vary the angle in vertical displacement in response to the sensor output signal reaching a preselected threshold. As a result, product damage associated with different fall trajectories from a conveyor into a collection bin are lessened. 
     An alternate conveyor system includes a conveyor having a first end fixed about a pivot and a second end, and having a conveyance surface together with the ends defining a conveyance plane for the transport of a product in contact with the conveyance plane beyond the second end. A collection bin having a base for receiving the product is provided, the base of which defining a collection plane vertically displaced below the conveyance plane, and a collection angle measured from the first fixed end through the vertical displacement. A pivot mechanism declines the second end to decrease the collection angle relative to the pivot; a sensor monitoring product collection height on the base, the sensor generating an output signal corresponding to the product collection height. A controller activates the pivot mechanism to vary the collection angle in response to the sensor output signal reaching a preselected threshold. 
     A process for limiting the drop of a product from a conveyor includes transporting the product along a conveyor. By sensing the vertical displacement between a collection bin surface receiving product coming from the conveyor and/or the height of product collecting in such a bin, one is able to pivot either the conveyor or the bin through an angular range to maintain the vertical displacement within a preselected range. By control of the angular range and the vertical displacement, product damage associated with different trajectories between a conveyor and a collection bin are lessened. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1(A)  is a top schematic view of an inventive conveyance embodiment in which a collection bin pivots, and (B) a top schematic view of another inventive embodiment having a chute intermediate between the bin and conveyor; 
         FIG. 2  is a side view in partial cutaway of the inventive embodiment depicted in  FIG. 1(A) ; 
         FIG. 3  is a perspective view of an inventive embodiment of an inventive conveyor system in which a conveyor portion position is variable in the course of product conveyance; and 
         FIG. 4  is a top view of the inventive embodiment depicted in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention has utility as a conveyance system that limits the height from which a product drops upon leaving a conveyor and enters a collection bin. In limiting fall of a product from a conveyor into a collection bin, product momentum is reduced thereby limiting product rejection. Greater precision in moderating product fall is obtained by sensing the vertical displacement between the conveyor and the base of an unfilled collection bin or a product mound developing within the collection bin. 
     Referring now to  FIGS. 1(A) and 2 , an inventive conveyor system is shown generally at  10 . The conveyor system  10  has a conveyor  12  extended between two guide rollers  14  and  16 . A motor (not shown) is mechanically coupled to the drive wheel  18  and serves to rotate the drive wheel thereby reducing movement of the conveyor  12  between guide rollers  14  and  16 . The conveyor  12  has an upper surface  22  that defines a conveyance plane. A product P being transported by the conveyor  12  is in contact with the conveyance plane until reaching the end of the conveyor  12  corresponding to the tangential surface thereto of one of the guide rollers  14  or  16 , platen  17  optionally spans the distance therebetween. While the conveyor  12  is depicted in the figures as a belt conveyor, it is appreciated that other conventional conveyor types are also operative herein illustratively including chain, and roller. The guide rollers  14  and  16 , drive wheel  18 , motor, and tensioning rollers are all secured to a stationary frame  24 . 
     Product P is loaded onto the conveyor  12  from a variety of sources illustratively including manual loading, a feed conveyor, and an auger. 
     A product P placed upon the upper surface  22 , regardless of the feed source for the conveyor  12 , is transported along the conveyance surface  22  in a direction commensurate with the rotational direction of the drive wheel  18 . Upon a product P reaching the end of the conveyor  12 , the product falls from the conveyor  12  into a collection bin  28 . The collection bin  28  has a base  30  and at least one sidewall  32 , the base  30  defining a collection plane. A collection angle α is measured as the shortest linear length connecting the conveyance plane and the collection plane. In prior art systems, the conveyance plane and collection plane are fixed, typically defining an angle α of 90 degrees. In the present invention, a pivot  34  is provided to vary the angle α so as to maintain the fall distance a product P endures in moving from the conveyor  12  into the bin  28  within a preselected range. As depicted in  FIG. 1 , it is appreciated that a collection bin  28  that is empty or nearly empty is pivoted to an angle α such that α product P falling into the bin  28  initially contacts a bin sidewall  32  to thereafter fall into a corner between the base  30  and sidewall  32  or into contact with the base  30 . The pivot  34  in conjunction with an actuator forms a pivot mechanism. An actuator operative in the present invention illustratively includes a worm gear, and a hydraulic piston. Preferably, the actuator is a hydraulic piston  36 . A sensor  38  monitoring the vertical displacement between a fixed point relative to the conveyance surface and a vertically displaced portion of the collection bin  28  is measured by a sensor  38 . Preferably, the sensor  38  is horizontally displaced relative to the guide roller  14  by an amount approximating the arc of fall for a product P based on the linear speed of the conveyor  12 . More preferably, the sensor  38  is secured to a mount  40  positioned above the conveyance plane in order to lessen debris and contaminant accumulation associated with either the product P or the conveyor  12 . In those instances where the conveyor  12  operates at a variety of speeds thereby producing varying product fall trajectories, the sensor  38  moves laterally along the mount  40  with a stepper motor interfaced to the revolutions per minute or power requirements of the conveyor drive motor. 
     The sensor  38  operative herein illustratively includes ultrasonic, optical, and magnetic. The choice of sensor being dictated by the factors illustratively including the nature of the product P, signal interference associated with the conveyor components or the collection bin. Preferably, the sensor  38  is an ultrasonic sensor. The sensor  38  regardless of the mechanism of product collection height within the bin generates an output signal corresponding to the height of product P within the bin  28 . A controller  43  receives the output signal from the sensor  38  and activates the pivot mechanism through the hydraulic piston  36  in order to vary the angle α in response to the sensor output signal reaching a preselected threshold. The preselected threshold typically being a product collection height that is becoming comparatively high and thereby decreasing the product fall height to below a preselected threshold. Alternatively, when the angle α as depicted in  FIG. 2  becomes too large, the vertical fall a product P would experience would exceed a preselected threshold. In typical operation, a collection bin  28  begins to receive product P with the angle α being at the minimum extremum and as the collection bin  28  fills, the angle α increases due to a maximum extremum of 90 degrees in the embodiment depicted in  FIG. 2 . With periodic or continuous sensor output signal being received by the controller and the pivot mechanism being adjusted in response thereto, a feedback mechanism is provided to assure product fall heights are maintained within a preselected range. 
     In the preferred embodiment depicted in  FIGS. 1A and 2 , the conveyor  12  is bidirectional with like components being denoted with the same numerals as detailed above with the exception that the numerals are now primed. An inventive conveyor system having multiple collection bins provides the added benefit of allowing one to continue product collection while another collection bin is being exchanged. In a still more preferred embodiment, additional ease of collection bin exchange and safety are provided by providing a cradle  42  sized to receive a collection bin  28  thereon with the cradle  42  moving about the pivot  34  under the action of the hydraulic piston  36 . Still more preferably, a safety cage surrounds the collection bin  28  in order to lessen the possibility of inadvertent contact with the collection bin  28  during the course of the change in angle α and vertical displacement. 
     In operation, an inventive system  10  upon being energized has both cradles  42  and  42 ′ in a position where the angle α is about 90 degrees. An empty collection bin is then loaded into either of cradle  42  or  42 ″. With a collection bin in place, the controller is activated corresponding to that particular conveyor end. The controller then pivots the appropriate cradle loaded with a collection bin into a minimum angle α fill position in preparation to receive product. The conveyor then begins to move in the direction of the empty collection bin and product begins to fill the collection bin. With conveyor movement, the sensor begins providing output signal to the controller as to the fill height of product within the collection bin. Upon a sensor output signal indicating that product mound height has attained a preselected level, the hydraulic piston begins to increase the angle α between the conveyor end and the collection bin through movement of the cradle. Sensor output signal and adjustment in the angle α continues until the filling collection bin reaches a maximal angle α. Typically the maximum angle α is 90 degrees with the minimum fill angle being greater than 10 degrees and often greater than 20 degrees. With a collection bin at the maximal angle α, the process can be repeated with the opposing collection bin being placed onto the opposing cradle. With the first collection bin arriving at a maximum angle α position and the sensor providing output that the collection bin has been filled to a preselected level, the conveyor reverses direction of conveyance and begins to fill the second collection bin without a disruption of product movement. The filled collection bin is then amenable to removal and optionally replacement as a second collection bin fills in a process as detailed above. In the event that a first collection bin attains a maximal angle α and has been filled to a preselected level based on sensor output and a second collection bin is not in a minimum angle α position, ready to receive product, then the controller stops movement of the conveyor. After a preselected amount of time with the conveyor in a stop mode, typically 5 to 500 seconds, a visual and/or auditory alarm indicates to an operator that the inventive system is in a standby mode. 
     During the operation process a mechanical safety cage is preferably provided. Still more preferably, a light curtain is active in those regions where an operator could potentially sustain an injury. If at any point during the operation process a light curtain beam is broken on the operating side of an inventive system, the controller responds accordingly. In the instance where one collection bin is filling and the second collection bin is not at a minimal angle α position, the conveyor is stopped and the operator is required to clear any obstructions along the light curtain beam path prior to the inventive system allowing restart. In the instance where a collection bin is filled and the opposing bin is in a minimum angle α position and ready to receive product, the conveyor will reverse direction and begin to fill the second collection bin and the operator must assure that any obstructions along the length of a light curtain beam have been removed prior to the controller allowing system restart. Upon restart, an operator designates the conveyor direction and thereby which bin to continue filling. In instances where both collection bins are in a minimum angle α position and a light curtain beam is broken on the side to which no fill is currently occurring, the conveyor will cease operation and an operator must assure that area is likewise free of obstructions prior to restart. 
     While the present invention is depicted in  FIGS. 1A and 2  with respect to a reversible direction conveyor capable of feeding product to collection bins at the opposing ends of the conveyor, it is appreciated that an inventive conveyor system is also provided with a single direction conveyor coupled to a diverter chute system as depicted in  FIG. 1B  in which a flap valve  48  or other conventional gating system, as opposed to reversing conveyor direction, shunts product to a particular collection bin. While the chute system depicted in  FIG. 1B  has two collection bins for the sake of clarity, it is appreciated that a larger number of collection bins can be coupled therewith. A chute-based conveyor system according to the present invention having more than two collection bins finds particular utility in instances where a high throughput product is collected in comparatively quickly filled collection bins, as is the case for instance with numerous edible products such as produce. Multiple gate diverter chute systems are well known to the art and operative herewith. U.S. Pat. No. 4,143,752 is indicative of a multiple gate chute system. 
     Referring now to  FIGS. 3 and 4 , an alternate inventive conveyor system is depicted generally at  60 . The conveyor system  60  finds particular application in the filling of comparatively large collection bins that are not amenable to pivoting in order to dynamically change a collection angle α. As such, the conveyor  60  has a conveyor  62  that pivots about a fixed end  64  to effectively decrease the collection angle α as previously defined by pivoting the conveyance plane of the conveyor  62  relative to a static collection plane as previously defined. The conveyor  62  receives product P from any number of sources including a parallel conveyor, a non-parallel feed conveyor, an auger, and manual placement. Product P is fed to the conveyor  62  in the region proximal to the fixed end  64  as from a hopper shown in ghost. The conveyor  62  has two guide rollers  66  and  68 . The support platen  70  is secured to a frame  72  by way of a pivot  74  extending from an arm  76 . The frame  72  anchors a first end  78  of an angle modifying actuator  80  depicted herein as a hydraulic piston. The actuator  80  has a second end  82  pivotally attached to the support platen  70  remote from the pivot  74  to create a conveyor with a variable collection angle conveyor. The conveyor  62  provides a dynamic collection angle α upon a sensor as detailed herein being affixed proximal to the free conveyor guide roller  68 . However, there is often a requirement that not only is the collection angle α dynamic but also control is maintained of product trajectory into a collection bin. While a collection bin  80  can be translated in the linear direction of conveyor product movement, preferably the frame  72  has a wheeled undercarriage  82  traversing a rail  84  under the control of an actuator driven motor  86 . The rail  84  resting on supports  88  bounding the collection bin  81 . The travel of the wheeled carriage  82  on the rail  84  is limited by conventional means illustratively including the coupling of a mechanical brake to the rail  84  at the travel limits for the wheeled carriage  82  or alternatively through the use of a conventional proximity sensor. Travel limits on the wheeled carriage  82  are provided to avoid collision between a declined conveyor  62  and an inexactly positioned collection bin  81 . 
     In situations where the collection bin  81  has a width considerably greater than that of the conveyor  62 , a transverse spreader  90  is preferably attached to the conveyor  62  proximal to the free guide roller  68  through attachment to the support platen  70 . A spreader  90  is typically indicated where the collection bin  81  has a width of greater than twice the width of the conveyor  62 . The spreader  90  as depicted in  FIGS. 3 and 4  is a conveyor mounted to the support platen  70  by way of a pivot allowing rotation of the spreader  90  through an angle of up to 180 degrees where the direction of travel for the conveyor  62  defines a 0 degree central point. It is appreciated that a spreader according to the present invention also can take the form of a rotating wheel or a rotatable chute. A sensor  38  having attributes as described above with respect to  FIGS. 1A and 2  is mounted proximal to guide roller  68  in instances when an optional spreader  90  is not present. When a spreader  90  is present, sensor  38  is optionally mounted to the spreader  90  or continues to extend from the conveyor  62  from a frame that extends so as to project a beam towards the collection bin  81  in the vicinity of product trajectory. In recognition of the collection angle α changing as a result of conveyance plane modification, the sensor  38  is secured to a mount  40  as detailed above with respect to  FIGS. 1 and 2  by way of a pivot pin  92  that is generally parallel to pivot  74  such that the sensor  38  is providing readings of product height as a vertical displacement measurement relative to the sensor  38 . 
     The conveyor system  60  is particularly well suited for the filling of highway vans and rail cars with particulate materials to provide balanced loading and limit airborne particulate during the loading process. In operation, a collection bin  81  is placed between rail supports  88  and the conveyor  62  is declined to the minimal collection angle α relative to the base  83  of the collection bin  81 , shown in ghost in  FIG. 3 . Depending on the width of the collection bin  81  relative to the conveyor  62 , the spreader  90  is locked or allowed to traverse. In the event that the collection bin  81  is less than about twice the width of the conveyor  62 , the spreader  90  is locked at a 0 angle at a 0 angle position. In instances where the conveyor bin  81  is wider than about twice the conveyor width, the spreader  90  is allowed to rotate relative to the 0 angle position. Preferably, when the spreader  90  is rotating, the conveyor  62  is positioned along the midline relative to the long axis of the collection bin  81 . With the conveyor  62  in a minimal collection angle position relative to the collection bin base  83 , the conveyor  62  is activated and the sensor  38  begins to provide continuous or periodic output signals to the controller  94  when the product height within the collection bin  81  has reached a predetermined height. Upon product collection reaching a predetermined height, an incremental rotation of the spreader  90  is performed by the controller until a maximal rotation angle for the spreader  90  is obtained, at which point rotation of the spreader  90  in the opposite direction occurs with an incremental traverse of the wheeled carriage  82  occurring under the command of the controller  94 . With this process the spreader rotation and wheeled carriage translation along the rails continues until the wheeled carriage reaches the end of the rail travel  85 . At the end of the rail travel  85 , the controller drives actuator  80  to increase the collection angle α and initiate wheeled carriage travel towards the other rail travel end  87  while the spreader  90  rotates through an angle range determined by the collection bin width. This process is continued until the collection bin  81  is filled and the conveyor  62  is returned to a collection angle α such that the collection bin  81  can be cleared from beneath the inventive conveyor system  60 . 
     Patent documents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These documents and publications are incorporated herein by reference to the same extent as if each individual document or publication was specifically and individually incorporated herein by reference. 
     The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.