Abstract:
A method and apparatus for separating and accelerating adjacent objects on a conveyor, which does not interpose fingers, fixtures, escapements, or the like, between the objects. The apparatus uses two adjacent sideflexing conveyors traveling, at least in part, in a curved path. Separation and acceleration of the objects is accomplished by taking advantage of the increase in velocity at the margin of the conveyor in relation to the pitch line speed where the conveyor travels in a curved path. The objects are transferred from the higher speed margin of one conveyor to the low speed margin of the other, faster, conveyor, at the curve.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to an apparatus and method for separating adjacent objects on a conveyor. More particularly, the present invention is directed to a conveyor system which is capable of expanding a distance between two adjacent objects while moving the objects from one conveyor to another. 
     Separator conveyors are used to separate objects on a moving conveyor line. Usually, objects to be conveyed from one point to another in a manufacturing line are fed to a conveyor which moves the objects throughout the line. Generally, objects are fed in bulk to a conveyor line. The objects may be fed through a combining apparatus which aligns the objects in single file. Such a device is illustrated for example in U.S. Pat. No. 4,544,059. After the single file line of objects is formed, the objects tend to remain in line, against one another. Depending on the manufacturing line, a spacing may be desired between adjacent objects in order to carry out certain screening, inspection or other operations on each object. If the objects are too close together, an operation being performed on one object may interfere with an operation being performed on an adjacent object. Accordingly, it is important to control spacing of adjacent objects on the conveyor line. 
     In certain known separation conveyors, a mechanical device physically separates adjacent objects. For example, U.S. Pat. Nos. 1,689,247 and 1,463,527 disclose serpentine conveyor systems wherein a rotating drum having pins or fingers physically separate objects as they pass around the drum on the conveyor belt. 
     U.S. Pat. No. 3,386,558 discloses a feeder mechanism in which a device having fixed, radially extending arms is cam driven so that, as the device rotates, pneumatic suction cup gripping means at the ends of the arms travel along a path for removing folded carton blanks from a hopper and depositing them atop stacked containers moving along a conveyor belt. Rotationally eccentric movement is provided to the means which carries the fixed arms thereon. 
     U.S. Pat. No. 3,834,522 shows a transfer machine comprising a turret having a plurality of radially translatable carriages mounted thereon, which carriages are fitted with a suction cup for gripping a container. A cam track moves the carriages radially outwardly during rotation so as to enable the suction cups to grip the container at the unloading station, then retracts radially inwardly for transporting the container, and then moves radially outwardly to feed the container into the stacking device. The turret provides for intermittent movement between the stations to allow sufficient dwell time for the freshly printed containers to dry. 
     U.S. Pat. No. 4,369,875 discloses a slightly different arrangement wherein a series of pins is rotatingly maintained on a separate endless belt conveyor. The endless belt conveyor is driven at approximately the same rate as the feed conveyor. As objects pass the endless belt conveyor, the pins are inserted between adjacent objects thereby spreading the distance between those objects. 
     U.S. Pat. No. 4,726,876 discloses an apparatus for changing the spacing between articles of a moving array of discrete articles, and includes transfer means mounted for orbiting along a closed orbital path passing through a receiving zone and a discharge zone. The orbital radius of the transfer means is adjustable to provide an orbital radius in the discharge zone which is different from that in the receiving zone. The transfer means are maintained in fixed, equal angular distances between them along the orbital path whereby the orbital path distance between adjacent transfer means is different in the discharge zone from that in the receiving zone thereby resulting in a different spacing between adjacent articles in the discharge zone from that in the receiving zone. Two or more orbital spacer means may be utilized in tandem to provide the change in spacing in stages. 
     Other types of mechanically operated systems are also known. In each case, a device is generally engaged between adjacent objects to force the objects apart. There are several problems associated with these types of systems. Because the separator is an independently driven device, it must be controlled separately. The separate control system can be expensive and if the system breaks down, separation cannot be maintained. Yet further, the known techniques of separation require insertion of a device between adjacent objects. If the objects are fragile, they may be easily broken or damaged by insertion of the separating device. In addition, the physical touch may cause dirt or other unwanted contamination. The shape of the objects may render this approach unworkable. 
     The present invention is used to separate adjacent objects on a conveyor line so that certain manufacturing operations can be performed on the objects, while at the same time avoiding the problems associated with the prior known techniques of separation. 
     It is, therefore, an object of the present invention to provide a separating conveyor system which is free of the aforementioned and other such disadvantages wherein adjacent objects on a moving conveyor can be spaced from one another without the use of independent separating devices. 
     To achieve these and other advantages, the present invention is a conveyor arrangement, which accelerates and separates adjacent objects. The separation is accomplished with minimal contact and without interposing any separating means or devices. It requires little or no adjustment to work with a variety of shaped and sized objects. 
     The conveyor arrangement uses at least two so-called sideflexing conveyor chains arranged side-by-side similar to the conveyor chains shown in U.S. Pat. Nos. 4,823,939 and 5,779,027. This type of conveyor comprises flat topped links, which present an approximately continuous moving surface to the objects being conveyed. 
     The invention includes an area of the conveyor where two such chains are moving in a curve and are adjacent and parallel. 
     The objects to be conveyed and separated are introduced in single file on the first chain, and are riding near one margin of the chain. When the chain enters the curve, the ends of the links where the objects are riding accelerate and separate. Each conveyor section includes a plurality of links. Each link tapers from its mid-section toward each end. When the chain enters a curve the taper allows the spaces between links to close without interference on the side toward the center of curvature and to open on the opposite side. Objects are placed onto the idle end of the first conveyor, The guide rail crowds the objects toward one edge of the conveyor. 
     The objects are transferred from the first chain to the second chain in the curve, by a guide rail. They are now riding on the margin of the second conveyor. When the second conveyor leaves the curve and enters a straight, the link ends separate and accelerate, further separating the objects. The second chain is driven at a higher speed than the first chain. The linear velocity of the edge of the first chain at the outside of the curve is increased in consequence of the curvature and the linear velocity of the edge of the second chain at the inside of the curve is reduced in consequence of the curvature. The speeds of the chains are adjusted so the adjacent edges of the two conveyors along the curve are approximately the same. It is understood that “linear velocity” refers to the time rate of change of position of a body. 
     In an advantageous embodiment of the invention, the second chain enters a curve in the opposite direction, further accelerating and separating the objects. In this curve the objects are transferred to the third chain and the transfer and acceleration occurs, and when the third chain enters a straight-line section, the objects are again accelerated and separated. The process is same as transfer from first chain to second, and constitutes a second stage of the same process. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is schematic top view of a preferred embodiment of the instant invention; 
     FIG. 2 a  is a diagrammatic plan view of two links of a preferred embodiment of a conveyor chain showing the preferred linkage; 
     FIG. 2 b  is an end elevational view of the conveyor chain link shown in FIG. 2 a;    
     FIG. 3 is a diagrammatic plan view of a conveyor chain including a plurality of the links shown in FIGS. 2 a  and  2   b  showing the swiveling action of the links as the chain passes from a curved to a straight to a curved path of motion; 
     FIG. 4 is a diagrammatic plan view of a conveyor chain having adjacent objects thereon with the objects passing from curved to straight, and straight to curved, portions of the path, showing the objects becoming separated and accelerated; and 
     FIG. 5 is a diagrammatic plan view of adjacent conveyor chains showing objects being guided from one chain to the other in the curve, being separated and accelerated by virtue of the higher speed of the second chain. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Attention is first directed to FIG. 1 which shows a preferred embodiment of the present invention. The separator conveyor system generally designated by the numeral  10  comprises a first conveyor  12 , a second conveyor  14 , and a third conveyor  15 . First conveyor  12  comprises a feed section  16 , a first separation section  18 , and a first straightaway section  20 . Third conveyor  15  comprises a second separation section  24 , and a second straightaway, or discharge, section  26 . Feed section  16  merges into first separation section  18  at the line designated  28 . First separation section  18  then merges into first straightaway section  20  at the line designated  30 . // First straightaway section  20  of first conveyor  12  merges into second separation section  24  of third conveyor  15  at the line designated  32 . Second separation section  24  then merges into second straightaway section  26  at the line designated  34 . First separation section  18 , first straightaway section  20 , and second separation section  24  comprise a separation zone. 
     Second conveyor  14  comprises a first separation section  38  merging into a first straightaway section  40  which merges into a second separation section  42 . As can be seen from FIG. 1, second conveyor  14  runs alongside first conveyor  12  and third conveyor  15  in the separation zone. 
     First, second, and third conveyors  12 ,  14 , and  15  are preferably chain conveyors using links  44  of the type shown in FIGS. 2 a  and  2   b.  Each link  44  comprises a generally planar top plate  46  having a center hinge eye  48  at its trailing end and a pair of complementary hinge eyes  50  at its leading end. The leading end of each link  44  is pivotally connected to the trailing end of an adjacent leading link  44  by a first hinge pin (not shown). The trailing end of each link  44  is pivotally connected to the leading end of an adjacent trailing link  44  by a second hinge pin (not shown). The leading and trailing edges  52 ,  54  of each link  44  are beveled to permit relative pivotal movement or sideflexing in the horizontal direction. A sufficient number of links  44  is assembled into an endless sideflexing chain according to the desired size and configuration of the assembly in a manner which is well-known in the art. Links  44  may be fabricated of a suitable plastic or metal. Links of other shapes may be used as long as the desired flexing effect can be achieved. A suitably constructed elastomer belt could be used. 
     A sideflexing chain is shown in FIG. 3 where the action of links  44  as they pass from a curve  56  to the right, to a straight section  58 , and into a curve  60  to the left can be seen. A plurality of links  44  are joined in a manner already described. In an area where the chain is rounding a curve to the right as shown at  56 , the links  44  pivot so leading edge  52  of one link  44  essentially comes into contact with trailing edge  54  of the next adjacent link  44  at the inside of the curve. The gaps between the left ends of the links  44  are at their widest. At straightaway section  58 , the links are essentially symmetrically situated around the longitudinal axis with the gaps between adjacent links  44  at each end being essentially the same. In this area, the velocity has increased. When the chain is in a curve to the left as shown at  60 , the leading and trailing edges  52 ,  54  of adjacent links  44  come into contact at the inside of the curve, the gaps between the right ends of the links  44  are at their widest, and the velocity is further increased. The direction of movement of the chain is shown by arrow  62 . 
     Attention is now directed to FIG. 4 where, again, the direction of movement of the chain is shown by the arrow  62 . Successive positions of two objects being conveyed are shown. In the first position, at curve  56 , objects  64  and  66  may be separated or, as shown in FIG. 4, are essentially in contact. Once the objects have moved out of curve  56  into the straight  58 , the ends of links  44  have drawn apart, thereby separating objects  64  and  66 . As the objects  64  and  66  pass into curve  60 , the ends of links  44  are further apart, thereby still further separating objects  64  and  66 . 
     As can be seen from FIG. 5, objects  64  and  66  are shown with some separation between them at straight section  65  of first chain  12 . Chain  12  enters curve  67  and the objects acquire additional separation. Guide  84  moves the objects to chain  14  in the curve. As a consequence of the relative speeds of chains  12  and  14  they may acquire more separation as shown at  69 . Guide  86  may or may not be needed as determined by the speed of the machine and the shape and size of the parts. 
     When chain  14  moves from curve  71  to straight  73 , the objects are further separated. Depending on the nature of the objects, and the process to be applied to them, this may be an adequate separation. Otherwise, as in FIG. 1, the conveyor system has another stage of separation. The objects handled by the inventive system can be both rounded and irregular in shape, mandating the second stage. 
     Returning to FIG. 1, the objects to be handled are fed to feed section  16  of the first conveyor  12  by a feeder generally designated by the numeral  68 . Feeder  68  comprises a hopper  70  in which the objects to be handled are stocked in bulk, an elevator conveyor  72 , and a prefeeder  74 . The hopper  70  is below the level of the separating conveyor. The elevator conveyor  72  raises the objects from hopper  70  and deposits them in prefeeder  74  which then feeds them by vibration in a known manner onto the feed section  16  of first conveyor  12 . As will be appreciated by those skilled in the art, any known type of feeder to feed the objects to be handled to the conveyor can be used. 
     Objects to be handled drop randomly from prefeeder  74  on to the feed section  16  of first conveyor  12 . Conveyor  12  includes an adjustable guide  76  which moves the objects to one margin of the chain. At the same time, the objects are marshaled into single file. Guide  76  is adjustable to account for objects of varying shapes and sizes and may include fixtures (not shown) to discriminate the objects based on their orientation, and may turn the objects or reject some of them to fall back to hopper  70 . Although guide  76  is illustrated as a pivotable bar, other embodiments are also contemplated, such as a pneumatic system, a robotic arm, or a fixed guide rail. 
     First conveyor  12  is driven by a motor and transmission  78  as is well-known in the art. Second conveyor  14  is also driven by a known motor and transmission arrangement  80 , preferably at a higher speed than first conveyor  12 . Third conveyor  15  is also driven by a known motor and transmission arrangement  81 , preferably at a higher speed than second conveyor  14 . The difference in speed between the first and second conveyors, and between the second and third conveyors, can easily be determined by those skilled in the art. Conveyors  12 ,  14 , and  15  are all driven in the direction shown by the arrow  82 . 
     Conveyors  12  and  14  are positioned such that adjacent edges of the chains align and the tops of the chains are essentially coplanar, thereby allowing for easy movement of articles from one chain to another. Suitably adjusted guides  84  and  86  move the objects from first conveyor  12  to second conveyor  14 . Guides  84  and  86  can be of similar construction as guide  76 . Similarly, conveyors  14  and  15  are positioned such that adjacent edges of the chains align and the tops of the chains are essentially coplanar, thereby allowing for easy movement of articles from one chain to another. Suitably adjusted guides  88  and  90  move the objects from second conveyor  14  to third conveyor  15 . Guides  88  and  90  can be of similar construction as guides  76  and/or guide  76 . 
     The mode of operation of the conveyor system  10  will now be described with reference to FIG.  1 . Objects to be handled, stored in hopper  70 , are conveyed to prefeeder  74  by elevator conveyor  72 . Prefeeder  74  then feeds the objects to feed section  16  of first conveyor  12 . It is to be distinctly understood that any suitable feed apparatus could be used to feed the objects to the conveyor  12 . The hopper-elevator conveyor-prefeeder arrangement is the presently preferred such device. 
     The objects are then guided by guide  76  into single file and onto second conveyor  14  by guides  84  and  86 . The objects are separated and accelerated where chain  12  enters the curve at first separation section  38  and the ends of links  44  separate. The objects are further separated and accelerated during the transfer to chain  14  and again where chain  14  leaves the curve and enters the first straightaway section  40 . 
     Guides  88  and  90  guide the objects from second chain  14  to third chain  15  at the second separation section  24 . The objects are separated where chain  14  enters the curve, again where they transfer to chain  15 , and again where chain  15  exits the curve and enters the final straightaway  26 . 
     In the embodiment shown, the objects then pass through a machine  92  which affixes an adhesive label, a device  94  to press the label firmly in place, a reading station  96  which confirms the label is readable, and a blow off station  98  which takes the objects which do not have readable labels and deposits them into bin  100 . The objects then go on to the next processing stage schematically shown at  102 . Element  102  may be a bin, or another conveyor, or any suitable continuation of the flow. Suitable sensors, whether photoelectric or mechanical, controllers, etc., all well-known in the art, may be used to control the operation of all or part of the system. 
     The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.