Conveyor for removing an article conveyed abreast of another article

Abstract: An article removal conveyor which receives side-by-side traveling articles, causes an outer one of the side-by-side articles to be separated laterally outwardly from an inner one of the side-by-side articles so that the outer article will fall off a downstream conveyor. The article removal conveyor (40) includes an inner side wall (42) formed by an upright driven belt (43), and three rows of driven rollers (54,56,58) defining an inner conveyor lane (44), a middle conveyor lane (46), and an outer conveyor lane (48). The rollers (54) of the inner lane (44) are skewed to bias articles toward the side wall (42). The rollers (56) of the middle late are skewed to bias articles away from the side wall. The rollers (58) of the outer lane are not skewed.

Description: Background of the Invention The present invention relates to the positioning of articles, such as packages, into a single file. It is known to provide a conveying system which receives a flow of randomly arranged articles, such as packages to be mailed, and orients the packages into a single column or file so that the packages can be fed one-at-a-time to a sorter mechanism. The sorter mechanism includes a scanner which reads a code on each package, and a diverter which diverts the packages to particular travel paths in response to the data read from the code, e.g., a mailing address. As depicted in FIG. 1 the conventional conveying system typically comprises an unscrambler or singulator conveyor 10 which has a series of driven rollers 12 whose rotary axes are skewed relative to a longitudinal direction of travel so that the packages are conveyed simultaneously longitudinally forwardly (in direction L) and laterally inwardly toward a side wall 16. As a result, the packages tend to become united in single file traveling longitudinally along the side wall. Such a conveyor is disclosed for example in US-A-4,039,074. Upon exiting the outlet 18 of the singulator conveyor 10, the line of packages is conveyed to the sorter mechanism to be directed to respective stations in accordance with a code marked on the packages. Packages may sometimes leave the singulator conveyor while traveling abreast, i.e., in side-by-side relationship (e.g., see packages P1 and P2 in FIG. 1) which will interfere with proper operation of the sorter mechanism, since the scanner is able to read a code from only one package at a time. Consequently, a flow control mechanism 20 (shown in FIG. 1) has been proposed for the purpose of causing an outer one P2 of the side-by-side packages to be removed. Such a flow control mechanism 20, which is disclosed in US-A-5,222,586, comprises a conveyor belt 22 positioned to receive packages exiting the singulator conveyor 10. The width of the belt 22 is such that any package whose center of gravity G (assumed for conveyor-designing purposes to lie at the geometrical center of the package) is situated laterally to the outside of the outer edge 24 of the belt 22 will fall onto a discharge chute 26. This means that an excessively wide package will fall onto the chute, as will the outer one P2 of two side-by-side traveling packages P1, P2 in most instances. It may on occasion occur, however, that the center of gravity of the outer package, e.g. package P4 of the side-by-side traveling packages, will be situated laterally inside of the outer edge 24 of the belt 22 and thus be carried onto a downstream conveyor 28, e.g., a belt for conveying packages to a scanner mechanism. As pointed out earlier, a scanner mechanism is not able to properly read the codes on packages traveling in side-by-side relationship. It would be desirable therefore, to provide a mechanism for more reliably preventing packages from entering the conveyor 28 in side-by-side relationship. DE-A-2916780 discloses a conveyor mechanism in which each of the conveying lane applies a conveying force having a lateral directional component as well as a forward directional component. The rollers of the center conveying lane are adjustable between a right-skewed position and a left-skewed position, because the center lane only functions as a switch to displace articles to the right or to the left. The center conveying lane is not intended to convey articles in only a forward direction, like the conveying lane of the present invention. Further, all of the rollers are formed of the same material having the same coefficient of friction. Thus, in order for a particular conveying lane to take control of an article, a major part of the article must be placed on that conveying lane. Summary of the Invention The present invention involves a conveyor mechanism comprising inner, middle, and outer parallel conveying lanes and an upright side wall disposed adjacent an inner edge of the inner lane. Each of the conveying lanes is arranged to advance articles longitudinally forwardly. Furthermore, the inner lane is arranged to urge articles laterally inwardly toward the side wall, and the middle lane is arranged to urge articles laterally outwardly away from the side wall. Preferably, each of the inner and middle lanes comprises driven rollers that are skewed in opposite directions with respect to the longitudinal direction. The third lane preferably comprises driven rollers arranged to impart no lateral outward force on articles riding thereon. The rollers of the outer lane preferably rotate about axes oriented perpendicular to the longitudinal direction. The upright side wall is preferably driven longitudinally forwardly and is formed by an endless belt. The present invention also relates to a method of advancing articles. The method involves providing inner, middle, and outer conveying lanes, at least the inner and middle lanes being formed of rows of driven rollers. The rollers of the inner lane are driven about axes that are skewed relative to a longitudinal direction to urge articles longitudinally forwardly and laterally inwardly against a longitudinally forwardly moving upright side wall. The rollers of the middle lane are driven about axes that are skewed relative to the longitudinal direction to urge articles longitudinally forwardly and laterally outwardly away from the side wall. The outer lane is driven to urge articles at least longitudinally forwardly. An article which extends entirely across only the inner and middle lanes is conveyed so as to be displaced laterally inwardly against the side wall while being advanced longitudinally. An article extending entirely across all of the inner, middle, and outer lanes is conveyed so as to be displaced laterally inwardly against the side wall while being advanced longitudinally. An article riding only on both of the middle and outer lanes is conveyed so that when such article is discharged from downstream ends of the middle and outer lanes onto a downstream surface having an outer edge, the center of gravity of such article is situated laterally outwardly of such outer edge, whereby such article will fall off the downstream surface. Brief Description of the Drawings The objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof in connection with the accompanying drawing in which like numerals designate like elements, and in which: FIG. 1 is a plan view of a conveying system according to the prior art; FIG. 2 is a plan view of a conveying system according to the present invention; FIG. 3 is a view taken in the direction of arrows 3-3 in FIG. 2; FIG. 4 is a plan view of a removal conveyor of the present invention when a first size package is being conveyed thereon; FIG. 5 is a top plan view of the removal conveyor with no packages conveyed thereon; FIG. 6 is a view similar to FIG. 4 with a second size package being conveyed thereon; FIG. 7 is a front end view of FIG. 6; FIG. 8 is a view similar to FIG. 7 depicting what would occur if the outer conveyor lane were not present; and FIG. 9 is a view similar to FIG. 6, depicting what would occur if packages are conveyed thereon in side-by-side relationship. Detailed Description of a Preferred Embodiment of the Invention A conveyor system according to the present invention is depicted schematically in top plan view in FIG. 2. Depicted therein is the downstream end of the previously described conventional unscrambler or singulator conveyor 10 which has skewed rollers 12 for advancing articles, such as packages, in a direction having a longitudinal forward component L and a lateral inward component L'. Hence, the packages are advanced forwardly while being arranged in single file against a vertical side wall 16. As indicated earlier in connection with FIG. 1, it may occur that packages exit the singulator conveyor 10 in side-by-side relation. It is necessary that one of those packages be removed in order to avoid the situation where two packages travel simultaneously to a scanner mechanism. As explained earlier in connection with FIG. 1, this is usually accomplished by means of the conventional flow control mechanism 20, but under certain conditions, side-by-side packages may pass through the flow mechanism. In order to prevent such an occurrence, the present invention concerns a removal conveyor 40 positioned between the singulator conveyor 10 and the flow control mechanism 20. The removal conveyor comprises a vertical inner side wall 42 formed by a driven endless belt 43 which travels in the longitudinal forward direction L. A horizontal conveyor mechanism is provided which comprises an inner conveyor lane 44, a middle conveyor lane 46 and an outer conveyor lane 48. Each of those conveyor lanes comprises a row of rollers 54, 56, 58 driven by a conventional drive mechanism, e.g., motor-driven endless bands 52. The rollers 54, 56, 58 lie in a common horizontal plane. The conveying lanes are designed so that each lane advances packages longitudinally forwardly, and furthermore so that: (i) the inner lane 44 applies a lateral inward force to the packages, (ii) the middle lane applies a lateral outward force to the packages, and (iii) the outer lane 48 applies no lateral outward force to the packages. (Preferably, the outer lane 48 applies no lateral force whatsoever to the packages.) The manner in which this is achieved will now be explained. The rollers 54 of the inside lane are skewed such that their lateral outer ends 54 are situated forwardly of their lateral inner ends 54. Consequently, the inside lane 44 applies to packages a conveying force acting in a direction having the longitudinal forward component L and the lateral inward component L. Hence, packages advanced by the inner lane are also biased against the inner side wall 42. The rotary speed of the inner lane rollers is preferably selected in order to advance packages longitudinally forwardly at the same speed as the inner side wall 42. The rollers 56 of the middle conveyor lane 46 are skewed such that their lateral inner ends 56 are disposed forwardly of their lateral outer ends 56'. Thus, the middle lane 46 applies to packages a conveying force acting in a direction having the longitudinal forward component L and a lateral outward component L". The rollers 58 of the outer conveyor lane 48 have their axes oriented perpendicular to the longitudinal direction L and thus apply to packages a conveying force acting solely in the longitudinal direction L. It is necessary that the inner and middle lanes 44, 46 operate so that a package P5 (see FIG. 4) that is wide enough to extend entirely across only the inner and middle lanes 44, 46 will be moved laterally inwardly (as well as longitudinally forwardly), i.e., that the package P5 will be under the control of the inner lane from the standpoint of lateral movement. That is achieved in the preferred embodiment by (a) skewing the rollers 54, 56 of the inner and middle lanes at the same angle relative to the longitudinal direction (as viewed in plan), (b) making the inner rollers 54 longer than the middle rollers 56 so that the width WI of the inner lane is larger than the width WM of the middle lane (i.e., WI>WM), and (c) driving the inner and middle rollers at the same speed. It will be appreciated, however, that other arrangements are possible for ensuring that the lateral movement of the packages is controlled by the inner lane. It is also required that a package P6 (see FIG. 6) which is wide enough to extend entirely across all three lanes 44, 46, 48 will be moved laterally inwardly (as well as longitudinally forwardly). As noted above, the middle rollers 56 are unable to move such a package P6 laterally outwardly, so that requirement can be achieved by ensuring that the outer rollers 58 do not impose a sufficiently large lateral outward force on the package which, when combined with the lateral outward force of the middle rollers, is able to overcome the lateral inward force applied by the inner rollers 54. This can be accomplished by arranging the outer rollers 58 such that they impose no lateral force on the packages, preferably by mounting those rollers for rotation about axes oriented perpendicular to the longitudinal direction. Hence, only a longitudinal force would be imposed on the packages by the outer rollers. Of course, it may be possible to skew the outer rollers 58 so that they impart a slight lateral outward or lateral inward force, without causing the inner rollers to lose control over the lateral movement of the packages. The primary purpose for the provision of the outer conveyor lane 48 can be understood with reference to FIGS. 6-8. It will be appreciated that in the absence of the outer lane 48, the package P6 would tilt and rise off the rollers 54 of the inner lane (as shown in FIG. 8), whereupon the package P6 would come under the control of the middle lane and be displaced laterally outwardly off the outer edge of the removal conveyor 40. That is undesirable, as the package P6 is not intended to be removed. However, due to the presence of the outer lane 48, the package P6 will remain seated on all three lanes, and will be urged against the side wall as explained above. It will be appreciated, then, that the purpose for providing the outer lane is to prevent the undesired removal of the very wide packages P6 without preventing the desired removal of an outer package traveling abreast of an inner package, as will be later explained in connection with FIG. 9. A further requirement of the removal conveyor 40 is that a package riding on both the middle and outer lanes, but not on the inner lane (e.g., see the package position P8' shown in FIG. 9), must become oriented so that when discharged onto a downstream conveyor, such as a flow control conveyor 20, the center of gravity CG of the package lies laterally outside of the outer edge 62 of the downstream conveyor and will fall off that edge 62. That is accomplished in the preferred embodiment by making the outer lane 48 shorter in width than the middle lane (i.e., WM>WO), and driving the outer rollers 58 at a speed such that the forward longitudinal speed component of the middle rollers 56 is the same as that of the outer rollers. This involves rotating the outer rollers 58 slightly slower than the middle rollers 56 since the middle rollers are skewed but the outer rollers are not. The operation of the removal conveyor in removing a package will now be explained with reference to FIG. 9. In FIG. 9 a pair of packages, (i.e., inner and outer packages P7, P8) have exited the singulator in side-by-side relationship, and it is necessary to remove the outer package P8. The inner package P7 comes under the influence solely of the rollers 54 of the inner lane 44 and is advanced thereby longitudinally forwardly and laterally inwardly against the moving side wall 42. The outer package P8 initially comes under the influence solely of the rollers of the middle lane 46 and is advanced thereby longitudinally forwardly and laterally outwardly toward the outer lane 48. Eventually, the outer package P8 will contact the rollers 58 of the outer lane 48 and assume an equilibrium position P8' partially on the outer lane and partially on the inner lane, whereby the center of gravity CG of the package (assuming that the package is of symmetrical mass) becomes offset laterally outwardly of the outer edge 68 of the middle lane. Hence, when the outer package P8 is transferred onto the flow control conveyor belt 22, its center of gravity will be offset laterally outwardly of the outer edge 62 of that belt 22, whereupon the package P6 will fall off the flow control conveyor belt 22 at position P8". That package P6 can travel down a conveyor of the chute 26 and be collected for recycling back to the singulator conveyor 10. It will be appreciated that the package P8 would be removed as described above even if an inner edge thereof had been initially riding on the inner lane, i.e., if the package P7 were of slightly less width, because the middle lane would exert lateral control over the package. Hence, such a package would eventually be displaced laterally outwardly to the position P8'. As noted earlier, the outer lane could be arranged to provide a slight lateral inward or outward movement to the packages without adversely affecting the ability of the removal conveyor to remove the outer package. If a slight lateral inward movement is provided, it is merely necessary to ensure that the outer edge 62 of the downstream conveyor 20 is positioned so as to lie laterally inside of the center of gravity of packages being conveyed only by the outer and middle lanes. In doing so, the assumption is made that the packages are symmetrical, i.e., the center of gravity coincides with the geometrical center of the package. It will be appreciated that the present invention provides a high degree of assurance that packages will be advanced only in single file to a sorting mechanism. Although the present invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims: A conveyor mechanism comprising: a first (44) and a second parallel conveying lane (46); an upright side wall (42) disposed adjacent an inner edge of the inner lane and extending in a longitudinal direction; and each of the first (44) and second conveying lanes (46) being arranged to advance articles longitudinally forwardly, the first lane (44) being further arranged to urge articles laterally inwardly toward the side wall (42), the second lane (46) being further arranged to urge articles laterally outwardly away from the side wall (42), the first lane (44) and the second lane (46) being arranged relative to each other such that an article extending across both the first lane (44) and the second lane (46) is urged toward the side wall (42), wherein each of the first lane (44) and the second lane (46) comprises driven rollers (54, 56), wherein the rollers (54) of the first lane (44) and the rollers (56) of the second lane (46) are skewed in opposite directions, respectively, with respect to the longitudinal direction, wherein the rollers (54) of the first lane (44) are skewed at a first angle relative to the longitudinal direction and the rollers (56) of the second lane (46) are skewed at a second angle relative to the longitudinal direction, wherein the rollers (54) of the first lane (44) are longer than the rollers (56) of the second lane (46). The conveyor mechanism as set forth in claim 1, wherein the first angle is equal to the second angle. The conveyor mechanism as set forth in claim 1, further comprising a third conveying lane (48) parallel to the first lane (44) and the second lane (46) disposed on an opposite side of the second lane (46) from the first lane (44) and arranged to advance articles longitudinally forwardly, The conveyor mechanism as set forth in claim 3, wherein the third conveying lane (48) comprises driven rollers (58), The conveyor mechanism as set forth in claim 4, wherein the rollers (58) of the third lane (48) rotate about axes oriented perpendicularly to the longitudinal direction. The conveyor mechanism as set forth in claim 4, wherein the third lane (48) is arranged to impart no lateral outward force on articles riding thereon. The conveyor mechanism as set forth in claims 3 or 6, wherein the first lane (44), the second lane (46), and the third lane (48) are arranged relative to each other such that an article extending across the first lane (44), the second lane (46), and the third lane (48) is urged toward the side wall (42). The conveyor mechanism as set forth in claim 3, wherein each of the first lane (44), the second lane (46), and the third lane (48) comprises driven rollers (54, 56, 58). The conveyor mechanism as set forth in claim 9, wherein the rollers (54) of the first lane (44) are longer than the rollers (56) of the second lane 46). The conveyor mechanism as set forth in claim 10wherein the rollers (56) of the second lane (46) are longer than the rollers (58) of the third lane (48). The conveyor mechanism as set forth in claim 1, wherein the side wall (42) is driven longitudinally forwardly. The conveyor mechanism as set forth in claim 12, wherein the side wall (42) comprises an endless belt (43). The conveyor mechanism as set forth in claim 1, further comprising a downstream surface (20) disposed at an exit end of the first lane (44) and the second lane (46) for receiving articles therefrom, the downstream surface (20) including an outer edge (62) situated laterally inwardly with respect to an outer edge of the second lane (46). A method of advancing articles, comprising the steps of: A) providing first (44) and second conveying lanes (46), the first and second conveying lanes each comprising rows of driven rollers (54, 56), the rollers (54) of the first lane (44) being longer than the rollers (56) of the second lane (46); B) driving the rollers (54) of the first conveying lane (44) about axes skewed at a first angle relative to a longitudinal direction to urge articles longitudinally fowardly and laterally inwardly against a longitudinally fowardly moving upright side wall (42), the side wall extending in the longitudinal direction; C) driving the rollers (56) of the second conveying lane (46) about axes skewed at a second angle relative to the longitudinal direction to urge articles longitudinally fowardly and laterally outwardly away from the side wall; D) conveying an article that extends entirely across the firrst (44) and second conveying lanes (46) so that the article is displaced laterally inwardly against the side wall (42) while being advanced longitudinally.

Inventors: BOONE JOSEPH T, BOONE, JOSEPH T.
Applicants: SANTRADE LTD, SANTRADE LIMITED
Application year: 1996
Main classification: B65G47
IPC codes: B65G47, B65G13