Abstract:
A conveyor mechanism for transferring an article from a primary conveyor to a secondary conveyor that extends in a direction normal to the direction of the primary conveyor. The secondary conveyor has a receiving location at which it receives articles from the first conveyor. The second conveyor has a flat support surface over which a perforated continuous conveyor belt extends. A vacuum plenum is inlayed into the flat support surface and has openings in its upper plate that are located at the receiving location. A vacuum source is connected to the vacuum plenum for creating a vacuum in the vacuum plenum that pulls air through the perforated continuous conveyor belt which causes objects that are deposited on the secondary conveyor at the receiving location to be pulled to and held against the upper surface of the perforated continuous conveyor belt.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a conveyor transfer system and, more particularly, to a method and mechanism for transferring objects from a primary conveyor to a secondary conveyor that is moving in a direction normal to the direction of the primary conveyor. The prior art includes a wide variety of techniques and mechanisms for transferring an article being transferred along a primary conveyor to a secondary conveyor that is moving in a different direction, usually in a direction that is normal to the transfer direction of the primary conveyor. For example, in U.S. Pat. No. 5,887,699, articles are transferred from a primary conveyor to a secondary conveyor by a rotating mechanism that includes an extending arm that is mounted for rotation and operated by a hydraulic cylinder such that a portion of the article extends across the side of the primary conveyor and is frictionally engaged by the secondary conveyor. Another example of a prior art conveyor diverting system is shown in U.S. Pat. No. 5,927,465 that utilizes a pair of diverting tracks and diverting gates that are moved into position to divert articles that are to be directed to the secondary conveyor. Generally, the prior art devices include structural mechanism such as turning devices, arms for rotating the articles and pivoting mechanism for re-orienting the articles to be transferred to the secondary conveyor. These prior art devices depend upon the article and the structural mechanism engaging in a predetermined way and are susceptible to malfunctioning if the size or shape of the article changes or the article is not orientated on the primary conveyor as anticipated. Also, the diverting arms, turning devices and pivoting mechanisms are, since they are exposed, vulnerable to being bent, broken or twisted, thus rendering them inoperative for their intended purpose. Furthermore, the diverting mechanisms are susceptible to wear and, when worn, they malfunction. The prior art devices are also complex, occupy considerable space, clutter and obstruct the conveyor area and are expensive to produce and maintain. Furthermore, many of the prior art devices are designed for specific articles and cannot be relied upon to function satisfactorily with other articles. As a result, there is a need for a simple, compact, reliable, adaptable and inexpensive mechanism for transferring articles from a primary conveyor to a secondary conveyor that extends at an angle to the primary conveyor. 
     BRIEF SUMMARY OF THE INVENTION 
     This principal object of this invention is to provide a method and mechanism for transferring an article being conveyed along a primary conveyor to a secondary conveyor that extends normal to said primary conveyor in a manner that overcomes the above discussed shortcomings of the prior art. To accomplish this, Applicant has provided a primary conveyor for conveying individual objects in a first direction toward its discharge end and a secondary conveyor for receiving objects at a receiving location from said discharge end of the first conveyor. The secondary conveyor then conveys the individual objects in a direction that is at an angle to said first direction. The first and secondary conveyors are arranged with respect to each other such that, when the conveyed objects reach the discharge end of said first conveyor, they are deposited on the receiving location of said second conveyor. The second conveyor has a flat support surface over which a perforated continuous conveyor belt extends. A vacuum plenum, having a flat upper surface, is inlayed in the flat support surface such that its flat upper surface lies in the plane of the flat support surface. There are slotted openings formed in the flat upper surface of the vacuum plenum. A vacuum source is connected to the vacuum plenum for creating a vacuum in said plenum that pulls air through the perforated continuous conveyor belt that moves over the flat support surface. The vacuum causes objects that are deposited on the secondary conveyor at the receiving location to be pulled to and held against the upper surface of the perforated continuous conveyor belt. The vacuum is sufficiently strong to stop the movement of the objects in the direction of the primary conveyor and to hold the objects against the upper surface the of perforated continuous conveyor belt. Once the movement of an object in the direction of the primary conveyor has been stopped, the object is conveyed along the second conveyor without the need for a vacuum to hold it against the upper surface of the perforated continuous conveyor. In accordance with Applicant&#39;s invention, there are no external arms, trays or diverters that can be bent or broken and, thus, disable the transfer mechanism. Applicant&#39;s mechanism provides for a positive transfer from the primary to the secondary conveyor that can be adjusted for objects of various sizes and weights by merely changing the level of the vacuum. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a plan view of two conveyors that intersect at a right angle. 
     FIG. 2 is a side view of the conveyor seen in FIG. 1 that is receiving conveyed objects from the other conveyor seen in FIG.  1 . 
     FIG. 3 is an end view of the conveyor seen in FIG.  2 . 
     FIG. 4 is an isolated perspective view of the vacuum mechanism used in this invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and the specific embodiment of the invention illustrated therein, a plan view of the conveyor apparatus  10  is shown in FIG. 1. A primary or first conveyor  12  has a flat conveying surface  14  along which objects  60  are conveyed in the direction indicated by the arrow P. As illustrated, the conveyor  12  is a belt conveyor but it should be understood that conveyor  12  could be any conventional type of conveyor, such as a belt or chain conveyor. The objects  60  thus are conveyed along the upper surface of conveyor  12  from the entrance end  16  toward the discharge end  18 . As best seen in FIG. 2, the primary or first conveyor  12  is supported by a frame  20  at a desired elevation above the ground. The frame  20  includes adjustable ground engaging feet  21  for the purpose of precisely adjusting and leveling the conveyor  12 . 
     An objective of this transfer system is to position the objects  60  on the secondary conveyor  30  with their longitudinal dimension normal to the direction of travel of conveyor  30  with the objects  60  parallel to each and spaced from each other by a minimum spacing. To accomplish this the width of the object  60  and the rate at which the objects are being deposited on primary conveyor  12  are factors that must be considered in establishing the conveying speeds for both conveyors  12  and  30 . 
     A secondary conveyor  30 , see FIG. 1, is arranged normal to the direction of feed primary conveyor  12 . It should be noted that this invention is not limited to the illustrated embodiment in which the primary and secondary conveyors are normal to each other, and will work equally well if the conveyors extend more or less than ninety degrees relative to each other. As best seen in FIG. 2, the secondary conveyor  30  is supported by a frame  32  at a desired elevation above the ground. The frame  32  includes adjustable ground engaging feet  33  for the purpose of precisely adjusting and leveling the conveyor  12 . In the preferred embodiment, the support surface of secondary conveyor  30  is adjusted such that it is slightly lower than the conveying surface of primary conveyor  12 . 
     The secondary conveyor  30  includes a flat stationary support surface  34  that extends the length of the conveyor. The upper rung of a perforated continuous conveyor belt  42  is supported by the stationary support surface  34 . The perforated continuous conveyor belt  42  wraps around a roller at each end of the conveyor, one of which is driven by a drive mechanism  46 . The drive mechanism  46  drives the belt  42  in the direction indicated by the arrow S such that the upper band rung moves from the receiving end  36 , past the receiving location  38  and than on to the discharge end  40 . 
     The primary conveyor  12  discharges the conveyed objects  60  to the receiving location  38  of the secondary conveyor  30 . The flat stationary support surface  34  of the secondary conveyor has a portion cut away into which is inlayed a hollow or vacuum plenum or open ended chamber  44 . The hollow chamber  44  is shown in an isolated view in FIG.  4 . The hollow chamber  44  includes a rectangular portion  45  and an open flared end portion  46 . The upper plate  47  of the hollow chamber  44  has a plurality of open slots  48  formed therein. The hollow chamber  44  is inlayed in the flat stationary support surface  34  such that its upper plate  47  is in the plane of the flat stationary support surface  34  with the slots  48  extending in the direction of movement of the perforated continuous belt  42 . A head portion  50  for the hollow chamber  44  is secured to the side of the conveyor  30  such that the open flared end  46  is closed. The head portion  50  includes a back plate  51  having a slot  52  formed therein that permits communication between the hollow chamber  44  and the interior of the head portion  50 . The back plate  51  includes a tab  53  on each side that are used to secure the head portion  50  to the side of the conveyor  30 . A tube  54  is secured to the bottom of the head portion  50  such that the tube  54  communicates with the interior of the head portion  50 . As best seen in FIG. 2, a pump or vacuum source  56  is connected to the tube  54 . The vacuum source  56  is adjustable to permit the level of the vacuum that it draws to set for the particular conveying situation. As the weight of the object being transferred increases and its speed of transfer increases, a greater or stronger vacuum may be required. Applicant has found that a vacuum of two to six inches of Mercury is appropriate for his preferred embodiments. 
     As best seen in FIG. 1, the perforated continuous conveyor belt  42  has ten rows of perforations extending in the direction of movement of the belt and, as best seen in FIG. 4, there are ten slots  48  formed in the upper plate  47  of the vacuum plenum  44 . Each row of perforations formed in the perforated continuous conveyor belt is aligned with one of the slots  48  such that, when there is a vacuum in the vacuum plenum  44 , air is being drawn into the plenum  44  through the slots  48  and the aligned row of perforations. 
     The primary conveyor  12  is adjusted such that its discharge end  18  is at a slightly higher elevation than the upper surface of the perforated continuous conveyor belt  42  to ensure that objects  60  that are discharged from the primary conveyor  12  will be received on the upper surface of the conveyor belt  42 . 
     The operation of the conveyor apparatus is as follows. The drives for the primary  12  and secondary  30  conveyors are turned on and the vacuum source  56  is activated. The objects  60  to be conveyed are fed to the entrance end  16  of the primary conveyor  12 . As objects  60  are discharged from the discharge end  18  of the primary conveyor  12 , their momentum carries them toward the center area of the secondary conveyor  30 . The vacuum source  56  creates a vacuum in the hollow or vacuum plenum  44  which causes atmospheric air to be pulled into the plenum  44  through the slots  48  and the perforations that are passing over the slots  48 . The vacuum attracts the objects  60  to the upper surface of the perforated continuous conveyor belt  42  and is of sufficient force to stop their movement in the direction P. Since the perforated conveyor belt  42  is continuously moving in the direction S, the objects abruptly change direction as soon as they are attracted to the surface of the belt  42  by the vacuum. It should be noted that the vacuum plenum  44  is limited to the receiving location of the secondary conveyor  30 . By the time the object  60  has moved a slight distance along secondary conveyor  30 , its movement relative to the conveyor belt  42  ceases and the object  60  will continue to be conveyed in the direction S toward the discharge end  40  despite the fact that it is no longer attracted to the surface by the vacuum of the vacuum plenum  44 . 
     The following are several examples of the use of applicant&#39;s conveyor transfer method and mechanism: 
     EXAMPLE 1 
     Paper wrapped candy bars weighing, in the range of, 2 to 4 ounces are deposited on the primary conveyor at a rate up to 380 candy bars per minute. These candy bars are deposited on the primary conveyor with the long dimension of the package traveling parallel to the flow. The packages are cross-transferred onto the continuously moving cross transfer vacuum conveyor at a right angle to its flow, such that the packages are then traveling with their width parallel to the flow and their ends alligned. 
     EXAMPLE 2 
     Wrapped burritos weighing about 5½ ounces are deposited on the primary conveyor at a rate up to 300 per minute. The wrapped burritos are deposited on the primary conveyor with their longitudinal dimension traveling parallel to the flow. The wrapped burritos are cross-transferred onto the continuously moving cross transfer vacuum conveyor at a right angle to its flow, such that the packages are now traveling with their width parallel to the flow. 
     EXAMPLE 3 
     Soft pack packages of baby wipes, each package weighing about 1½ pounds are deposited on the primary conveyor at a rate up to 180 packages per minute. The soft pack packages are deposited on the primary conveyor with their longitudinal dimension traveling parallel to the flow. The soft pack packages are cross-transferred onto the continuously moving cross transfer vacuum conveyor at a right angle to its flow, such that the packages are now traveling with their width parallel to the flow. 
     Tests have been run transferring energy bars and candy bars at a rate in excess of 600 bars/minute. 
     Thus, Applicant&#39;s very simple device can change the direction of an object being conveyed without the need for any external guides, rotating mechanism, extending arms, diverting tracks and gates, all of which are costly, require maintenance, can damage the objects being conveyed and are less reliable. 
     It should be understood that, while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.