Surge control method and apparatus in conveyor systems

Abstract: A surge control apparatus and method are particularly adapted for the safe handling of highly crushable and/or tearable products, such as paper-based box-type aseptic packages. A flow of products along a conveyor (10) exiting an accumulator (12) is held until previously released products have progressed a predetermined distance down the conveyor (10) towards a subsequent workstation, such as a packer. If a product queue occurs within the accumulator (12), the upstream flow of packages (26) is halted, and the queued products are shifted relatively slightly downstream against a movable locator mechanism (242). The stopping and shifting isolates from production line pressures the packages to be removed from the conveyor. Through such isolation, adjacent package shear points are prevented as a vertically-oriented conveyor mechanism (16) is used for removing and subsequently returning packages to the conveyor. A movable transfer plate (50) beside the conveyor (10) is manipulated to facilitate the removal and return of packages without tearing of package paper coverings. Maintenance of a predetermined downstream product gap facilitates placement of the locator mechanism. After a removal sequence, several non-removed packages are forced upstream into a pre-shifted position for being re-clamped by an outfeed brake (234), so that subsequent downstream shifting steps may take place for proper isolation of further queued-up products before their removal.

Description: The present invention in general concerns an improved surge control method and apparatus in conveyor systems, and more particularly concerns an improved method and apparatus for providing surge control for easily damaged products being conveyed between two workstations. Due to numerous considerations, it is desirable to establish production lines which run smoothly, and in general, without interruption. However, circumstances often cause undesired or unexpected variations in the operating speed of different components comprising a production line. In fact, various components may from time-to-time experience a total failure, i.e., stoppage, for either a relatively temporary period of time or for a more prolonged period of time. Broadly speaking, the concept of surge control has heretofore been put forth, for example generally whereby the output of a relatively upstream production component is temporarily accumulated and subsequently fed to a downstream production line component. Such accumulation occurs primarily because the operating speed of the relatively upstream component overtakes that of the relatively downstream machine or workstation. Various accumulators have been provided for use with a production line having a plurality of workstations or production areas. The following are examples of such accumulators: One feature common to many prior art accumulators is the concept of a vertically-oriented conveyor or escalator-type mechanism, with plural, spaced flights thereon for the storage or accumulation of products between adjacent ones of such flights. Those of ordinary skill in the art will appreciate that indexing of such a vertical mechanism in alternate directions results in either removal or return of products from or to a conveyor belt with which the mechanism is associated. Various differences in the foregoing exemplary accumulators may exist in the particular methodology or apparatus for handling the products to be accumulated. For example, US-A-4,499,987 generally operates a stop in association with incremental movement of an array of fingers to clear a slug of cartons, until one or more detectors indicate that there is no further need for accumulation of cartons by the device 10. A second detector is used for activating a stop whenever a space for insertion of such stop is detected between cartons passing by on a delivery belt. As further example, US-A-4,560,057 uses a movable platform 50, or a diverting belt 62 or 132 for directing articles or packets from a main conveyor either into an empty compartment of a reservoir or into a secondary conveyor for subsequent transfer to or from a reservoir. A laterally moving plunger 52 is used in conjunction with the movable platform 50 for securing packets generally upside-down in an open or empty compartment 40a of reservoir 14. Without side plunger 52, the packets would fall back downward upon retraction of movable plunger 50. A second movable platform 56 is used during unloading of packets. In general, if products on a production line being subjected to surge control are substantially durable and rigid, then their precise handling and treatment may not be as critical as in the case of less durable or less rigid products. As the products involved become less rigid and more fragile, a point is reached where use of prior art accumulator systems can result in damage and even destruction of the products. One example of products which are subject to damage by either crushing or tearing are paper packages, such as 250 ml. size packages, as produced by Tetra Pak, Combibloc, or International Paper, Inc. Such packages are presently popular in this size, and others, for the marketing of drink products, such as juices, and other beverages. The manufacture of such products typically may involve aseptic conditions, thus resulting in a particularized need for an accumulator capable of successfully handling such packages. Also, such packages generally have relatively sharp corners and edges, further contributing to handling difficulties. Moreover, the need for a highly dependable, relatively large capacity accumulator, is particularly acute in connection with aseptic paper packages. For example, the paper used in a forming and/or filler machine for such types of products may be sterilized, such as by passage through a heated bath of hydrogen peroxide. If such machine or production is stopped, the paper (which is generally coming from a large roll) may soften and possibly break upon restart. Also, a relatively lengthy (approximately 1 hour) resterilization process may be needed in the event problems occur during a stoppage of such production area. Thus, for such reasons, and due to required efficiencies of running a profitable operation, the filler machinery must operate on a more or less continuous basis, thus virtually requiring dependable, high volume surge control despite the added problem of the ready damage potential (through crushing or tearing) of the packages involved. For numerous reasons, accumulator operations through manual intervention is not a viable alternative. For example, human handling of such particular products may itself result in accidental product damage (e.g., crushing) such as through storage in stacked layers, or through hurried handling. Moreover, intermittent human intervention can result in lack of necessary attention being given to other production line activities, and hurried, time-pressure activities of workers in and around production lines can (based on all circumstances of a given situation) create a significant risk of injury to the workers. GB-A-2 170 169 discloses apparatus for transporting cigarette packets between a packet filling machine and a packet wrapping machine. A conveyor line extends between the two machines and a buffer store is located along the conveyor for removing and accumulating packets from the line should the wrapping machine throughput fall below that of the filling machine, and for delivering packets to the line should the filling machine throughput lay behind that of the wrapping machine. GB-A-2 170 169 recognises the risk of damaging packets when packets are transferred to or from the buffer store, and teaches means for minimising the risks. GB-A 2 170 169 does not, however, contemplate surge control such as taught by the present Applicant, for regulating the orderly, spaced flow of packages to the machine downstream of the accumulating apparatus. The present invention recognizes and addresses various of the foregoing problems, and others, concerning surge control or accumulator operations. Thus, broadly speaking, a principle object of this invention is improved surge control or accumulator operations. More particularly, a main object is improved method and apparatus for surge control operations, especially pertaining to easily damaged products, such as aseptic paper packages. Generally this invention aims at reduced human handling of packages, particularly in connection with surge control operations, thereby resulting in reduced package damages and better quality production, with reduced risk of injury to the workers. The invention provides improved, automated accumulator devices for dependable and high volume surge control handling of readily damaged packages, thereby to permit production workers more regularly to perform their primary duties relating to the production line. Preferred embodiments of the present invention provide improved method and apparatus which facilitates successful accumulator handling of aseptic paper packages, without the risk of crushing them, or without tearing the paper coverings thereof. Embodiments to be described minimize or eliminate (if possible) shear points during handling of such products, and isolate such products from production line pressures during their removal and/or return relative a production line conveyor. Desirably, according to the present invention, an improved accumulator apparatus will have a "flow-through" design, so as not to adversely affect the production line with which it is associated should the accumulator fail. Additional objects and advantages of the invention are set forth herein, or will be apparent to those of ordinary skill in the art, from the detailed description which follows. Also, it should be appreciated that modifications and variations as to the specific illustrated and discussed features and steps hereof may be practiced in various embodiments, uses, and methodologies of this invention without departing from the scope of the appended claims. Such variations may include, but are not limited to, substitution of equivalent means features, or steps for those shown or discussed, and the reversal of various parts, steps, or the like. According to the present invention there is provided a method of surge control for products being transported via a moving conveyor belt means between two production areas, the method comprising: providing an accumulator device 12, 212 alongside the conveyor belt means 10, 210 intermediate the two production areas so that one of such areas is upstream of the accumulator device 12, 212 and the other production area is downstream of such device, the device 12, 212 being capable of controllably removing products from the conveyor belt means 10, 210 if there is a back-up of products being fed to the downstream production area; characterized by selectively holding back products emerging from the downstream end of the accumulator device 12, 212 so as to maintain a predetermined distance or gap between adjacent products moving towards the downstream production area; and controllably removing products from the conveyor belt means 10, 210 with the accumulator device 12, 212 if a predetermined queue of products develops within the accumulator device before the predetermined distance gap occurs between products emerging from the accumulator device. Also according to the present invention, there is provided apparatus for surge control of products being transported via a moving conveyor belt means 10, 210 between two production areas 214,216, the apparatus comprising: accumulator means 12, 212 for being positioned alongside a conveyor belt means intermediate two production areas so as to be upstream and downstream respectively of such areas, said accumulator means 12, 212 being operative for controllably removing products from the conveyor belt means 10, 210 and having an infeed side 22 and an outfeed side 24; and outfeed brake means 114, 118; 234 associated with said accumulator means outfeed side 24, for controllably holding back products emerging from the accumulator outfeed side; characterized by control means (e.g. at 38), operatively associated with the accumulator means 12, 212 and said outfeed brake means 114, 118; 234 respectively, for actuating said outfeed brake means to hold back products emerging from said accumulator means so as to maintain a predetermined distance gap between adjacent products moving towards the downstream production area 216, and for controlling said accumulator means to remove products from the conveyor belt means 10, 210 if a predetermined queue of products develops within the accumulator means before said outfeed brake means is de-actuated. The present invention relates to a method of surge control for products being transported via a moving conveyor belt means between two production areas. Such method of this invention comprises providing an accumulator device alongside the conveyor belt means intermediate the two production areas so that one of such areas is upstream of the accumulator device and the other production area is downstream of such device, such device being capable of controllably removing products from the conveyor belt means if there is a back-up of products being fed to the downstream production area; selectively holding back products emerging from the downstream end of the accumulator device so as to maintain a predetermined distance or gap between adjacent products moving towards the downstream production area; and controllably removing products from the conveyor belt means with the accumulator device if a predetermined queue of products develops within the accumulator device before the predetermined distance or gap occurs between products emerging from the accumulator device. The accumulator device can be of the type having a vertically-oriented conveyor with a plurality of spaced, outwardly extending vanes for accumulating products therebetween, with indexing of such conveyor in selected directions resulting alternatively in removal or return of products relative to a carrying surface of a production line. The accumulator device may be so arranged that given vanes may be situated in a null position for the passage of products on the conveyor therebetween, such vanes then acting as guide rails. A movable transfer plate may be provided generally opposite distal edges of the extending vanes in the vicinity of the production line, the plate having a transfer edge situated generally laterally from the carrying surface of the production line. With such a plate, the method can involve alternately lowering the transfer edge beneath the production line carrying surface whenever indexing the vertically-oriented conveyor for removing products from the production line, and raising the transfer edge above the production line carrying surface whenever indexing the vertically-oriented conveyor for returning products to the production line. With this method, edges of the producta being handled on the production line can be protected from damage due to operation of the accumulator device. The method of this invention involves the temporary accumulation off-line of excessive numbers of such products queued up between the two workstations. This method may include the provision of an apparatus adjacent the conveyor between the two workstations, and having accumulator means for selectively alternately removing and returning groups of products relative such conveyor. The method further includes the step of preventing products from leaving the accumulator apparatus until products previously released therefrom have passed a sensing point along the conveyor a predetermined distance downstream towards the second workstation from the apparatus, and initiating a product removal sequence if the preventing step results in a queue of products extending through the apparatus from the outfeed side thereof back to the infeed side thereof. The product removal sequence may preferably include the steps of stopping the flow of further products into the accumulator apparatus, relatively shifting slightly downstream the products within the apparatus queue; and thereafter operating the accumulator means for removing products from the conveyor, whereby such products are isolated from line pressure along the conveyor by such stopping and shifting steps, to prevent shear point damage thereto during their removal. With respect to the present apparatus for surge control of products being transported via a moving conveyor belt means between two production areas, it comprises accumulator means positioned alongside a conveyor belt means intermediate two production areas so as to be upstream and downstream respectively of such areas, the accumulator means being controllably operable for removing products from the conveyor belt means, the accumulator having an infeed side and an outfeed side. An outfeed brake means, associated with the accumulator means outfeed side, controllably holds back products emerging from the accumulator device outfeed side: and control means, operatively associated with the accumulator means and the outfeed brake means, respectively, serves to actuate the outfeed brake means to hold back products emerging from the accumulator means so as to maintain a predetermined distance gap between adjacent products moving towards the downstream production area, and for controlling the accumulator means to remove products from the conveyor belt means if a predetermined queue of products develops within the accumulator means before the outfeed brake means is de-actuated. An improved accumulator device disclosed herein has a vertically-oriented conveyor with a plurality of spaced, outwardly extending vanes for accumulating products therebetween, and indexing of such conveyor in selected directions results alternatively in removal or return of products relative to the conveyor belt line. Adjacent vanes of the accumulator device may be situated in a null position for the passage of products therethrough carried on the conveyor belt with such vanes acting as guide rails. The accumulator device disclosed herein includes a movable transfer plate generally opposite the distal edges of the extending vanes in the vicinity of the production line, and having a transfer edge situated generally laterally from the carrying surface of the production line; and means for controllably moving the movable transfer plate so as to lower the transfer edge thereof beneath the production line carrying surface whenever the conveyor is being indexed for the removal of products from the production line, and so as to raise the transfer edge above the production line carrying surface whenever the conveyor is being indexed for the return of products to the production line, whereby edges of products being handled on the production line are protected from damage due to operation of the vertically-oriented conveyor. The accumulator means has respective infeed and outfeed sides generally between which products may be removed from the conveyor. Infeed brake means may be associated with the accumulator means infeed side, controllable for stopping the entry of products along the conveyor into the accumulator means infeed side. Outfeed brake means may be associated with the accumulator means outfeed side, controllable for stopping products along the conveyor from emerging from the accumulator means outfeed side. With the foregoing arrangement, the control means preferably operates in a normal run mode alternately to acutate and de-actuate the outfeed brake means for preventing products from leaving the accumulator means outfeed side until a predetermined number of previously released products have passed a sensor means, and operates in a product removal mode whenever actuation of the outfeed brake means in the normal run mode results in a queue of products extending through the accumulator means from the outfeed side thereof back to the infeed side thereof. The product removal mode preferably involves actuating the infeed brake means to stop upstream products on the conveyor from entering the accumulator means infeed side, and de-actuating the outfeed brake means to permit relative downstream shifting of products on the conveyor within the accumulator means, and controlling the accumulator means for removing such products from the conveyor. In more detail, the accumulator means may be associated with infeed sensor means for detecting the presence of packages at the accumulator infeed end; outfeed sensor means for detecting the presence of packages at the accumulator outfeed end; and downstream sensor means for detecting the presence of packages on the conveyor belt at a predetermined distance downstream from the accumulator outfeed end. Further, the accumulator means can have a controllably movable locator member, situated at a point relatively just downstream from the outfeed brake and the accumulator outfeed end, for selectively interrrupting the flow of packages along the conveyor belt at that point, as well as a back-up mechanism, situated at such point relatively just downstream from the outfeed brake for selectively forcing packages at least slightly back upstream against the conveyor belt so as to be stopped thereat by the outfeed brake. Accumulator control means, responsive to the infeed, outfeed, and downstream sensor means, controls the accumulator conveyor mechanism, the infeed and outfeed brakes, the locator member, and the back-up mechanism, for selectively removing and returning packages relative the conveyor belt without damage to such packages, so that queued up packages are first isolated from production line pressure and thereafter are temporarily accumulated on the accumulator conveyor mechanism for subsequent reinsertion onto the production line. Embodiments of the present invention will now be described in more detail by way of non-limiting example only with reference to the accompanying drawings, in which: Figure 1 is a generally side, isometric view of an exemplary embodiment of the present invention situated relative to an existing production line or conveyor belt means with which the present invention may be practiced; Figure 2 is a cross-sectional view of the apparatus of Figure 1, taken along the line 2-2 indicated therein; Figure 3 is an enlarged, partial view of a portion of the embodiment shown in Figure 2, also illustrating certain aspects of present methodologies for practicing this invention; Figure 4 is another enlarged partial view similar to that of Figure 3, illustrating still further aspect of the present methodologies; Figure 5 is a partial, side elevational view, in generally diagrammatical form, for illustrating both the present apparatus and methodology; and Figure 6 is an enlarged, generally side plan view of movable locator means, and back-up means in accordance with the present invention. Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features, elements, or aspects of the invention. Those of ordinary skill in the art will appreciate that numerous variations and modifications may be made to the exemplary embodiments discussed and illustrated (or suggested) herewith, as well as associated methodologies, without departing from the scope of the appended claims. For example, this invention may be practiced with numerous different types and shapes of packages, though preferred embodiments are specifically adapted for use with aseptic paper packages such as produced by Tetra Pak, Combibloc, or International Paper, Inc., in the 250 ml. size, or similar. Figure 1 is an isometric, generally side view of an apparatus for practicing the present invention in association with, for example, a pre-existing production line or conveyor belt means 10. Preferably, such pre-existing conveyor means is entrained through or otherwise associated with accumulator apparatus 12 of the present invention, so that no separate or independent conveyor mechanism need be provided with apparatus 12. While, of course, a separate drive mechanism could be practiced, the illustrated arrangement is preferred since it permits a "flow-through" design, so that failure or malfunction of apparatus 12 in no way otherwise affects the operation of production line 10, which is generally operatively flowing in the direction of arrow 14. In the following brief initial overview of the present structure, reference will be made to Figures 1 and 2 collectively, since Figure 2 is a cross-sectional view of the Figure 1 embodiment. Accumulator apparatus 12 includes an accumulator means, which may comprise a generally vertically-oriented conveyor mechanism 16, which may in turn include a chain or belt 18 with a plurality of spaced, outwardly extending vanes or flights 20 thereon. As best illustrated in Figure 1, such flights 20 preferably extend generally from about an infeed end 22 of apparatus 12 to about an outfeed end 24 thereof. As indicated by Figure 2, individual packages 26 may be entrained between a pair of adjacent flights 20, and accumulated therein through indexing of vertical conveyor mechanism 16. Such indexing may be variously accomplished, such as with a pair of toothed drive wheels 28, or the like, selectively driven by a controlled electric motor 30 or its equivalents, as well understood by those of ordinary skill in the art. In essence, vertical conveyor mechanism 16, such as including components 18, 20, 28, and 30, is a structural component well known to those of ordinary skill in the art, as generally exemplified by the prior art references discussed earlier in this specification. Likewise, those of ordinary skill in the art will appreciate that indexing of drive wheels 28 results in sweeping of flights 20 over the conveyor belt means 10 with which apparatus 12 is associated. Depending on the direction of indexing, and the presence or absence of packages 26, such packages may either be removed from, or returned to, conveyor 10. For safety reasons, as well as aesthetic reasons, apparatus 12 may be variously encased in a housing 32, variously having sidewalls, end walls, and the like. Some walls may be transparent, so as to permit inspection of accumulated products, as represented by the visualized flights 20 in present Figure 1. Some walls may comprise removable panels, such as 34, removal of which facilitates maintenance of the apparatus. For clarity and simplicity, such panel 34 and a corresponding opposite side panel are not shown in solid line in present Figures 1 and 2. A further housing 36 is preferably provided externally of housing 32, and may receive and protect other features of the present constructions, such as a movable locator means, as discussed hereinafter primarily with reference to Figures 5 and 6. Similarly, another housing 38 may be provided generally external to housing 32, such as for safe receipt and support of control means for use with the present invention. Such control means may variously comprise electronic circuits, manifested either in hardware, software, or various combinations thereof, for receiving sensor inputs and controlling controllable members in accordance with the present invention, as hereinafter described. Those of ordinary skill in the art will appreciate that such control means may assume numerous forms so long as feedback or sensor signals are operated on as discussed hereinafter, and so long as controllable members or means are controllably actuated and de-actuated as also described below. Hence, a specific discussion of the hardware (or software) of such a control means or mechanism is not necessary for an adequate understanding of the present invention. Likewise, in order more clearly to illustrate the present structure and methodology, control lines for interconnecting required power lines, feedback or sensor lines, and control signal lines, are not explicitly illustrated in the figures though well understood by those of ordinary skill in the art. Preferably, during operation of the apparatus in accordance with the present invention, a predetermined distance gap is maintained between the outfeed end 24 of apparatus 12 and a point downstream therefrom, such as associated with a downstream sensor means 40. Feedback lines 42 from such sensor means are operatively associated with control means within housing 38, or its equivalents, for ultimately affecting operation of apparatus 12, as discussed hereinbelow primarily with reference to Figures 5 and 6. Such operation as described below beneficially results in longitudinal isolation of a slug (i.e., grouping) of packages from production line pressure, to permit removal of the slug of packages without significant shear point pressure between adjacent such packages. For example, present Figure 1 illustrates a line 44 of packages 26, which are riding on conveyor belt means 10, and which are entering infeed end 22 of apparatus 12 and emerging from outfeed end 24 thereof. Practice of the present invention preferably results in maintenance of a gap between emerging products between outfeed end 24 and sensor means 40. Thus, the illustration of present Figure 1 represents a generally uncontrolled or "flow-through" condition along conveyor belt means 10. In this condition, packages 26 are continually and contiguously aligned throughout apparatus 12 on that portion thereof within or closely associated with conveyor belt means 10. The exact condition is hidden from view in the isometric illustration of present Figure 1). In this condition, there is a significant amount of production line pressure all along line 44, which pressure can result in crushing (partial or otherwise) of packages 26 as a filler machine or other upstream production area continues to add packages 26 to production line 10. Without isolation of packages 26 between the infeed end 22 and outfeed end 24, operation of mechanism 16 (so as to sweep packages 26 from the conveyor belt means 10 using paddles or flights 20) would result in a package shear point, such as at point 46. A similar shear point would exist adjacent to infeed end 22. As discussed below, practice of the present invention prevents any significant shear points between longitudinally adjacent packages, thereby making possible safe and efficient handling of even highly crushable packages, such as the aseptic paper packaging discussed above. Exemplary structure and methodology for practice of the present invention is discussed in greater detail, below. One other aspect of the present invention represented in present Figures 1 and 2 is that certain of the flights 20 are situated in a "null" position, for unaffected passage of products therethrough. Means for establishing such position, whether manually or automatically, may comprise a hand crank or the above-discussed control means, so that any adverse affects to production line 10 may be neutralized by placing flights 20 in such null position in the event of a failure or malfunction of apparatus 12. Thereafter, necessary maintenance could be performed generally with production line 10 operating just as if apparatus 12 were not present. Present Figures 2 to 4 more fully illustrate other features of the present invention which contribute to elimination or minimization of package shear points, particularly in the lateral direction (rather than longitudinal, as referenced above) of conveyor belt means 10. Figures 3 and 4 illustrate an enlarged, partial view of the lower portion of mechanism 16, and other aspects of this invention. As illustrated in Figures 2 to 4, a transfer plate 50 is illustrated in side cross-sectional view. Such transfer plate is situated generally opposite the distal ends 52 of the plurality of outwardly extending flights, at least generally in the vicinity of production line 10. Also, significantly, a transfer edge 54 of such transfer plate is situated generally laterally from the upper-most carrying surface 56 of belt 10. The top-most run 58 as well as the return run 60 of belt means 10 is represented in present Figures 3 and 4. Transfer plate 50 is preferably movable, and is associated with means for controlling movement thereof, such as are preferably embodied with a pair of air cylinders 62 associated with each longitudinal end of plate 50 (which extends essentially the length of flights 20 along conveyor belt 10, as represented in Figure 1). As understood by those of ordinary skill in the art upon comparing present Figures 3 and 4, controlled movement of piston 64 (and the non-illustrated second air cylinder, if used) results in manipulation of transfer edge 54, as a result of pivoting of member 66 about fixed axis point 68 supported relative some fixed housing portion 70 of apparatus 12. Such housing portion may be associated with, or independent of, the protective covering 72 which is representatively shown around the lower or return run 60 of belt means 10. Member 66 pivotably interconnects with piston 64 at connection point 74, while the opposite end 76 of air cylinder 62 is also received in a fixed relationship with the housing of apparatus 12. The resulting movement of movable transfer plate 50, regardless of how it is controllably effected in accordance with the present invention, is to alternately raise and lower transfer edge 54 relative carrying surface 56 of conveyor belt means 10. As should be apparent to those of ordinary skill in the art, the relatively raised position of transfer edge 54 as represented in present Figure 3 is desired whenever conveyor 18 (illustrated with multiple chain drive links 78) is to be rotated counterclockwise (the direction of arrow 80) about central axis 82 thereof. With rotation of drive member 28 in a counterclockwise direction, the distal ends 52 of outwardly extending members 20 are likewise rotated in a counterclockwise sense so that with a proper "index" of drive wheel 28, a line or slug of packages may be moved from the position occupied by exemplary package 84 to that of exemplary package 86. Such action amounts to returning a grouping or slug of products to conveyor belt means 10. Whenever piston 64 of air cylinder 62 is retracted (i.e., moved in the direction of arrow 88 of Figure 4), transfer edge 54 is moved relatively downward in the direction of arrow 90 of such Figure 4. As is apparent from the illustration of such Figure 4, transfer edge 54 is thereby lowered to a point beneath carrying surface 56 of conveyor belt means 10, so that a lateral shear point along such transfer edge is prevented for packages being removed from such carrying surface. In other words, as axis 82 is driven in a clockwise direction (direction of arrow 92), an exemplary package in the position of package 86 is swept into a removed position as represented by package 84. As should be apparent to those of ordinary skill in the art, movement of a line of packages from either a position on conveyor belt means 10 to a position off of such belt, or vice versa, involves engagement of such row of packages with the full length of the involved flights 20 from infeed end 22 to outfeed end 24 thereof. For the sake of clarity, such actual engagement is not explicitly illustrated in each of present Figures 3 and 4, though representative engagement is variously shown in all of present Figures 2 through 4. Preferably, controlled movement of transfer plate 50 is, as needed, automatically effected responsive to either removal or return of products relative conveyor belt means 10, thereby advantageously reducing the accomplishment of lateral edge safety for such packages to issuance of a command signal to properly position movable transfer plate 50 before each removing or returning sequence to be actuated through appropriate rotation of drive mechanism 28. Another advantageous aspect of the present invention resides in the limited flexible nature of movable transfer plate 50, which preferably may be formed of a moderate gauge sheet metal or the like. A secondary edge 94 is defined on a edge of transfer plate 50 opposite that of transfer edge 54 thereof. Due to the limited flexibility, movable nature of transfer plate 50, actuation of air cylinder 62 (or other equivalent means for moving plate 50) results in an advantageous movement of edge 94. In this instance, limited flexibility may be thought of as a degree of rigidity adequate such that manipulation of transfer edge 54 of plate 50 results in a degree of movement at secondary edge 94 thereof. In particular, such secondary edge 94 is provided with an elongated opening 96, as represented by the encircled, top view of such member in bubble 98 of present Figure 3. A simple bolt 100 or the like may be used to secure housing members 34 and 102 of housing 32, with openings therein of a size corresponding with that of bolt 100 (preferably only slightly larger) being formed in each of members 34 and 102. By having a slotted opening 96, transfer plate 50 is either slightly pulled out relative the position of bolt 100 or pushed backward thereto, such that a further edge 104 thereof is manipulated alternately in the direction of, and opposite the direction of, arrow 106. Bolt 100 in effect guides movement of plate 50 in the vicinity of edge 94 thereof. Whenever air cylinder(s) 62 is actuated for movement of transfer edge 54 downwardly, to permit removal of packages from conveyor means 10, edge 104 is moved in the direction of arrow 106, and thus projects beyond adjacent edge 108 of member 102. Such slight projection again prevents the occurrence of a lateral shear point which could otherwise occur at the juncture between members 34 and 102 if the "live edge" effect of transfer plate 50 were not provided. As should be apparent to those of ordinary skill in the art, edge 104 is pushed by the limited rigidity (i.e., limited flexibility) of transfer plate 50 back towards bolt 100 (opposite the direction of arrow 106) whenever air cylinder piston 64 is extended, as is illustrated in present Figure 3. As is so illustrated, such movement renders an arrangement which makes possible passage of a row of packages 110 beyond such edge 104 without danger of shearing or tearing of such packages. Since aseptic paper packages by Tetra Pak, or similar, are covered with paper wrappers or the like, the movable transfer plate features of the present invention greatly facilitate surge control handling of such particular types of packages, by eliminating lateral shear points for such packages which could otherwise occur as an accumulator means operates. Figure 2 also representatively illustrates a further curved plate 112, which may be placed generally on the opposite side of apparatus 12 from movable transfer plate 50, so as to also oppose the distal ends of flights 20 for retaining products within such flights whenever they are in the inverted position as occurs to varying degrees whenever they are in the vicinity of conveyor belt means 10. If removal and return of packages is performed from only one side of conveyor belt means 10, then plate 112 may situated in a more or less fixed condition. However, in accordance with the present invention, plate 112 may be rendered movable and controllable in the manner described above with reference to movable transfer plate 50 if it is desired to permit removal and return of packages from either lateral side of conveyor belt means 10, details of which alternative embodiment should be understood and appreciated by those of ordinary skill in the art from the foregoing description. As also representatively illustrated in present Figures 3 and 4, a further air cylinder 114, or equivalent means may be fixed relative apparatus 12, such as at plural points 116, so that operation of such air cylinder actuates movement of stop block 118. When properly actuated, such stop mechanism 118 comprises an outfeed stop means or outfeed brake for selectively engaging and holding packages 26 as they are about to emerge from the outfeed end of apparatus 12. Various opposing members (not explicitly illustrated) may be used for permitting block 118 to trap a given package thereagainst. It is to be understood by those of ordinary skill in the art that the placement of such controllable outfeed brake means may be varied, generally so long as its position does not adversely effect operation of flights 20. For example, a position just downstream from the outfeed end of flights 20 would avoid undesired interaction or interference with the accumulator means. Another aspect of the present invention which should be apparent to those of ordinary skill in the art from the present disclosure and illustrations is that conveyor belt means 10 is preferably continuously moving whenever the associated production line is operative. Thus, without requiring an independent drive, stop operations of an outfeed brake means results in the continued movement of carrying surface 56 beneath a line of packages 86. Thus, controlled actuation and de-actuation of such a brake mechanism, in combination with more or less continuous operation of conveyor belt means 10, provides a controllable means for advancing packages relative apparatus 12. Such is equally true, regardless of the relative position of a given brake means, either upstream or downstream at some point along apparatus 12. Now referring to present Figures 5 and 6, additional aspects of the present invention, concerning both method and apparatus thereof, are explained as follows. Figure 5 illustrates in substantially diagrammatical form, a side plan view of a lower portion of an exemplary apparatus 12 in accordance with the present invention, and in accordance with which the present methodology may be practiced. Figure 6 illustrates in generally side (partially cut-away) plan view, exemplary locator means and back-up means for practicing certain aspects of the present invention. In Figure 5, an exemplary accumulator device 212 is situated alongside a conveyor belt means 210, intermediate to separate production areas 214 and 216. The essential production line flow is in the direction of arrow 218; hence, production area or workstation 214 is generally upstream from apparatus 212, while workstation or production area 216 is generally downstream therefrom. Workstation 214 may comprise a filler machine or the like, for instance to fill packages with fruit juices or other beverages. The filler machine normally also closes, or seals, the individual packages, which thereafter move relatively downstream along production line 210 towards a straw-applicator or a packing machine, as represented by workstation 216. Workstations 214 and 216 may represent other types of machines or stages in production, just as this invention may be practiced with other types of products. Since products of this particular nature are most frequently packed in film, e.g. cellophane by groups of three turned end-to-end, the solid lines 220 are intended to represent groupings of three individual packages (or some other predetermined number of product packages). Those of ordinary skill in the art will appreciate that such packages, while preferably thought of in terms of groups of three, are still actually individual packages within apparatus 212. Also, other groupings of other predetermined numbers of products may be practiced. Still in diagrammatic form, drive axis 82 has extending therefrom along the length of apparatus 212 the distal edge 222 of a given flight or vane 225 of an accumulator means, of the type having a vertically-oriented conveyor, as discussed generally above with the reference to mechanism 16. Infeed end edge 224 and outfeed end edge 226 of such vane avoid shear point contacts with the products because there is no overlap with the smaller portion of partial packages which are not to be taken into or accumulated between an adjacent set of such vane during a given product removal sequence. In other words, the line of products illustrated between points 228 and 230 are to be taken up into the accumulator means, and as is apparent with the relationship of respective point pairs 224/228 and 226/230, there will be no longitudinally adjacent package shear point interference. Brake means for both the infeed and outfeed ends of the apparatus 212 may be provided, such as the air cylinder mechanism 114 discussed above. The operative location of such infeed brake means is represented by member 232, while member 234 represents the operative position of outfeed brake means. Control of such respective brake means is effected in accordance with the present invention, as discussed hereinafter. Downstream sensor means 236 may comprise a photoelectric cell, proximity detector, or virtually any other type of mechanism for reliably indicating the presence or absence of packages or other forms of products thereat, or passing thereby. As represented in present Figure 5, downstream sensor means 236 is located a predetermined distance "A" downstream from the outfeed end of apparatus 212. While the absolute or actual length of such gap is not ordinarily critical, it is a preferred aspect of this invention that at least a predetermined gap be maintained between a predetermined number of products (e.g., 1, 3, or other numbers) emerging from the outfeed end of apparatus 212. Maintenance of such a gap yields up advantages as discussed below in connection with the present surge control methodology, and apparatus for practicing same. Furthermore, those of ordinary skill in the art will appreciate that such surge control aspects of the present invention may be applied to various groupings of a particular number of products, as well as individual products. In other words, the desired gap "A" may be maintained as to groups of three packages being released at a time collectively from the outfeed end of apparatus 212, rather than as between each individual pair of packages to be released therefrom. Groupings of three are particularly preferred, as referenced above, since the downstream packer units will typically operate on the individual packages in groups of three. Additional sensor means are representatively illustrated, such as the outfeed sensor means 238, and the infeed sensor means 240. Each of the respective means may comprise different forms of sensing mechanisms, mechanical, electrical, electrical-mechanical, or otherwise, as broadly referenced above. However, as diagrammatically represented in present Figure 5, infeed sensor means 240 may preferably comprise a bank of four separate sensing elements, which through various combinations of positive and negative readings, will not only indicate whether there is a stalled or jammed package at such point, but also whether a tilted or turned-over package is passing such point. In other words, if a package is moving on its side, rather than on its top or bottom, it will present a lower height profile resulting in a positive reading of the two lower members, but a negative reading in the two higher members of infeed sensor means 240. Generally, it is not desired for such tilted or "knocked-over" packages to enter accumulator 212, and such an infeed sensor means advantageously detects all such conditions to permit signalling for operator intervention or assistance. Lastly to be described with respect to exemplary structural apparatus is the present locator means 242, which in the preferred illustrated embodiment may be controllably placed vertically in or out of the flow of products along conveyor belt means 210, as represented by the double-headed vertical arrow 244. In essence, such mechanism 242 may be retractable into a protective housing 246 (see also housing 36 and its related discussion in present Figure 1). Virtually any direction or type of movement may be utilized, but an air-cylinder movement with controllable mechanism 248 (diagrammatically represented) is one preferred form of such aspect of the invention. Figure 6 illustrates an additional feature of the present invention, which may in a preferred embodiment be integrally incorporated into, or at least supported and carried on such locator mechanism means 242. Such further feature relates to a back-up mechanism or means, generally 250, which permits urging of products backwards (i.e., forced relatively upstream) against the normal flow along product line 210, as discussed hereinafter. As represented in the side, partially cut-away view, of present Figure 6, the entire mechanism 242 may be extended in the direction of arrows 252 and 254 so as to block the flow path of products 256 normally moving in the direction of arrow 258 along production line 210. Such extended position is represented generally in the dotted line illustrations of present Figure 6. The solid line illustrations thereof represent a retracted position, in which the lowermost edge 260 of locator mechanism 242 is above the top of packages of 256, so as to in no way interfere with movement thereof otherwise occurring relative conveyor means 210. However, once engaged in the extended position, controlled actuation of an air cylinder means or equivalent actuation mechanism 262 results, through various linkages, in the "backwards" or upstream movement (direction of arrow 264) of engagement member 266' (dotted line). Since engagement member 266 is, in the extended position of locator mechanism 242, in contact with the downstream side of a package 256, such package and any packages upstream therefrom are pushed or forced in a relatively upstream direction. Such action is particularly advantageous in the context of the present invention, in that it permits such package or packages contacting engagement member 266 or forced upstream thereby to be re-clamped by outfeed brake means 234, for purposes discussed hereinafter. Without reducing the clarity of Figure 6 through the addition of numerous reference numerals, those of ordinary skill in the art will appreciate that proper actuation of air cylinder means or equivalent drive means 262 results in pivoting of linkage member 268 in the direction of arrow 270 about axis 271, resulting in the above-discussed movement of engagement member 266 in the direction of arrow 264. With reference particularly to Figure 5 and 6, the following description outlines certain preferred operational sequences of the present invention, but not necessarily all aspects thereof, nor the only preferred embodiment thereof. During normal running operations, there is typically a relatively smooth (i.e., unjammed) flow of products or packages from upstream workstation 214, along conveyor belt means 210, to downstream workstation 216, without any excessive build-up or queuing of packages between such two workstations. During such normal running operations, control means within housing 38, or equivalents thereof, causes selected and controlled actuation and de-actuation of outfeed brake means 234, so that products are selectively held back from emerging from the downstream end of accumulator device 212 until a predetermined number of previously released products reach or clear downstream sensor means 236. Once a previously released package or group of packages (numbering such as 3) passes downstream sensor means 236, then outfeed brake means 234 is de-actuated to permit movement of ordinarily continuously moving conveyor belt means 210 to advance such additional packages downstream. It should be apparent to those of ordinary skill in the art that if proper signals are not received from downstream sensor means 236, it can be determined that previously released packages have not yet cleared such point, which would indicate either a relatively slow movement of products along production line 210 (regardless of the actual speed of the conveyor belt means itself), or indicate that a jam or blockage has occurred, for whatever reason (for example, due to slow operation of the straw-applicator, or a breakdown thereof). So long as previously released package(s) have not cleared downstream sensor means 236, packages held by outfeed brake means 234 continue to be held because the predetermined minimum distance gap "A" has not yet occurred. Depending on the particular sequence of occurrences, if outfeed brake means 234 has been holding, and subsequently infeed sensor means 240 indicates a jam, it may be assumed that a line of products have queued up along conveyor belt means 210 within apparatus 212, between the infeed end and outfeed end thereof. Once such occurs, in accordance with practice of the present invention generally, a product removal sequence is initiated. In other words, present apparatus switches from a normal run mode into a product removal mode, whereby mechanism 212 (see also mechanism 16 of present Figure 2) is actuated for removing a queued line or slug of products from conveyor belt means 210. Such removal sequence may be accomplished in various manners in accordance with the present invention, with the following comprising one exemplary embodiment thereof. During such exemplary product removal sequence, the queued products are permitted to shift slightly downstream, which typically would involve de-actuation of outfeed brake means 234, so that potential shear point or region 230 clears the downstream edge 226 of vein 225. Preferably, de-actuation of brake means 234 is preceded by placement of a locator mechanism, such as that represented by exemplary locator means 242, within the product flow relatively just downstream from the outfeed end of apparatus 212. Such operations result in a relatively slight downward shift of the entire product queue within mechanism 212. At some point during the product removal sequence, preferably infeed brake means 232 is actuated so as to isolate from production line pressure the queued up line of products or packages to be removed from conveyor belt means 210. Also, in embodiments which incorporate the present exemplary movable transfer plate 50 features, such movable plate would be manipulated into position for removal movement of packages relative the conveyor belt means 210 (i.e., moved into the position represented by present Figure 4). The foregoing stop and shift operations results in the above-mentioned isolation of the products to be removed (i.e., accumulated). When integrally performed in the overall methodology described above, i.e. when used in combination with maintenance of a gap "A" between apparatus 212 and downstream packages, the potential problem of a nearby or adjacent package 272 (present Figure 6) can be avoided so that movable locator mechanism or means 242 will not damage or encounter any packages during its operations. Otherwise, mechanism 242 might lower into a package, which would clearly result in its crushing, and its possible release of contents. Such condition, or even the prospect of such occurrence, could be highly undesirable in the event that aseptic packages are being handled. Of course, such occurrences would be undesirable even if aseptic packages were not involved. Further in accordance with certain aspects of the present invention, after apparatus 212 has been properly indexed or controlled for removing a line of queued up products or packages, backup means 250 may be actuated so that the downstream or leading edge package 274 in actual contact with engagement member 266 may be pushed sufficiently backwards against the flow 258 of conveyor belt means 210, so that it may be re-clamped by outfeed brake means 234. Thereafter, movable locator means 242 (preferably supporting and carrying backup means 250 thereon) may be removed from the normal product flow (i.e., returned to its solid line position as represented in present Figure 6). The advantage of such operations is that a subsequent relative downstream shift may be effected, so that subsequent product removal sequences may advantageously isolate the queued up products from production line pressures, resulting in the improved and beneficial operations discussed above. Once a product removal sequence is completed, it should be apparent to those of ordinary skill in the art that the infeed brake means may be de-actuated, and so-called normal run operations resumed until a predetermined excess product queue once again occurs. It should be further apparent to those of ordinary skill in the art that product return sequences may be alternately performed with the present structure, utilizing various methodologies in accordance with this invention. For example, infeed brake means 232 may be actuated so as to permit the return of packages from apparatus 212, whereby slugs or lines of previously removed or accumulated packages may be returned to conveyor belt means 210. When present and used, the movable transfer plate 50 is preferably moved into its position illustrated in present Figure 3, so as to prevent the lateral shearing of package of product edges on conveyor means 210 during such return operations. Other return sequence variations may be practiced, including variously incorporating alternative use of the above-mentioned movable locator means, and back-up means. Those of ordinary skill in the art should appreciate that numerous variations and modifications may be made to the foregoing exemplary embodiments and methodologies, For example, locator mechanisms may be used which are movable in and out of a product flow without necessarily being retractable in a vertical plane as is the presently illustrated exemplary embodiment. Likewise, actuation for drive members other than the several air cylinders shown herewith may be practiced, such as electrical/servo controls, hydraulic systems, or other actuating or drive mechanisms. Similarly, the number of packages controllably released in groups so as to emerge from the outfeed end of apparatus 212, may be varied. Similarly, the number of packages remaining (after a removal sequence) between the outfeed end 226 of vane 225 and the extended locator mechanism 242, may be varied. For present exemplary purposes only, Figure 5 illustrates such number of packages as being three. In other words, 27 packages are illustrated as being "stopped" during a product removal sequence, and 24 of such packages are actually removed. Other variations and specifics of particular embodiments are subject to selection by given users of the invention. For example, apparatus in accordance with this invention may be provided substantially in stainless steel or equivalent materials to permit sterile or other wash-down uses. Also, different sized vertical conveyor mechanisms may be used to achieve different volume capacities, such as twenty or thirty minutes of accumulations of a filler machine output, while requiring a minimum of production line space.

Claims: A method of surge control for products being transported via a moving conveyor belt means between two production areas, the method comprising: providing on accumulator device (12, 212) alongside the conveyor belt means (10, 210) intermediate the two production areas so that one of such areas is upstream of the accumulator device (12, 212) and the other production area is downstream of such device, the device (12, 212) being capable of controllably removing products from the conveyor belt means (10, 210) if there is a back-up of products being fed to the downstream production area; characterized by selectively holding back products emerging from the downstream end of the accumulator device (12, 212) so as to maintain a predetermined distance or gap (A) between adjacent products moving towards the downstream production area; and controllably removing products from the conveyor belt means (10, 210) with the accumulator device (12, 212) if a predetermined queue of products develops within the accumulator device before the predetermined distance gap (A) occurs between products emerging from the accumulator device. A method according to claim 1, wherein the accumulator device (12, 212) includes a generally vertical conveyor mechanism (16) with a plurality of spaced, outwardly extending vanes (20, 225) thereon for the accumulation of products between adjacent such vanes, the removing step includes indexing the vertical conveyor mechanism (16) so as to remove from the conveyor belt means (10, 210) a line of products queued within the accumulator device (12, 212), and the predetermined queue comprises a slug of products extending along the length of the entire vertical conveyor mechanism. A method according to claim 2, wherein the accumulator device (12, 212) further includes a movable transfer plate (50) operatively situated relative the conveyor belt means and distal ends of the said vanes (20, 225) and wherein the position of the movable transfer plate (50) is controlled during the removing of products from the conveyor belt means (10, 210) so as to prevent the occurrence of lateral shear points for such products as they are so removed. A method according to claim 3, wherein the movable transfer plate (50) has a transfer edge (54) situated generally laterally from the carrying surface (56) of the production line (10); and the method includes lowering the transfer edge (54) beneath the said carrying surface (56) whenever indexing the vertically-oriented conveyor (16) for removing products from the production line, whereby edges of the products being handled on the production line are protected from damage due to operation of the accumulator device (12, 212) for removing said products from the conveyor belt means (10, 210). A method according to claim 1, wherein the accumulator device (12, 212) further includes a locator mechanism, relatively just downstream from the downstream edges of the plurality of outwardly extending vanes, and against which products queued within the accumulator device are permitted to shift relatively downstream during the removing step, whereby a product shear point is prevented at the downstream edges of the vanes during the removing step. A method according to claim 5, wherein at least one product immediately adjacent said locator mechanism (242) is retained on the conveyor belt means during the removing step, and thereafter such retained product is moved relatively upstream so as to re-establish the predetermined distance gap to be maintained, which gap is diminished whenever products are initially permitted to shift downstream against the locator mechanism. A method according to claim 1, further including temporarily holding back further products from entering the accumulator device (12, 212) whenever such device is removing products from the production line (10); and prior to removing a queued line of products from the production line (10), slightly shifting such queued line relatively downstream to prevent the existence of an adjacent product shear point (46, 230) at the downstream edges of the extending vanes (20, 225) operatively associated with removal of such products. Apparatus for surge control of products being transported via a moving conveyor belt means (10, 210) between two production areas (214, 216), the apparatus comprising: accumulator means (12, 212) for being positioned alongside a conveyor belt means intermediate two production areas so as to be upstream and downstream respectively of such areas, said accumulator means (12, 212) being operative for controllably removing products from the conveyor belt means (10, 210) and having an infeed side (22) and an outfeed side (24); and outfeed brake means (114, 118; 234) associated with said accumulator means outfeed side (24), for controllably holding back products emerging from the accumulator outfeed side: characterised by control means (e.g. at 38), operatively associated with the accumulator means (12, 212) and said outfeed brake means (114, 118; 234) respectively, for actuating said outfeed brake means to hold back products emerging from said accumulator means so as to maintain a predetermined distance gap (A) between adjacent products moving towards the downstream production area (216), and for controlling said accumulator means to remove products from the conveyor belt means (10, 210) if a predetermined queue of products develops within the accumulator (12, 212) means before said outfeed brake means is de-actuated. Apparatus according to claim 8, wherein the accumulator means (12, 212) includes a generally vertical conveyor mechanism (16) with a plurality of spaced, outwardly extending vanes (20) thereon for the accumulation of products between adjacent such vanes (20), wherein indexing of the vertical conveyor mechanism (16) in use removes a queued line of products situated on the conveyor belt means (10, 210) within the accumulator means, while reversing of such indexing returns such products to the conveyor belt means, and further wherein said predetermined queue of products comprises a slug of products extending along the accumulator means from its outfeed side (26) back to its infeed side (24). Apparatus according to claim 8 or claim 9, wherein the accumulator means further includes means for positioning the vertical conveyor mechanism (16) so that a given pair of spaced vanes (20) thereof reside on respective lateral sides of the conveyor belt means (10, 210) to function as guide rails for products being conveyed thereby, so that presence of the apparatus along the conveyor belt means will not adversely affect the flow of products therealong if such apparatus is shut down. Apparatus according to claim 8, 9 or 10, wherein the accumulator means further includes a movable transfer plate (50) operatively situated relative the conveyor belt means (10, 210) and distal ends (52) of the outwardly extending vanes (20), there being means (62, 66) for controlling the position of the movable transfer plate (50) relative to the conveyor belt means during either the removing or returning of products relative the conveyor belt means so as to prevent the occurrence of lateral shear points for such products. Apparatus according to any of claims 8 to 11, wherein the accumulator means (12, 212) includes a generally vertical conveyor mechanism (16) with a plurality of spaced, outwardly extending vanes (20) thereon for the accumulation of products between adjacent such vanes (20), wherein indexing of such vertical conveyor mechanism (16) in use removes a queued line of products situated on the conveyor belt means (10, 210) within the accumulator means, while reversing of such indexing returns such products to the conveyor belt means, and further wherein said predetermined queue of products comprises a slug of products extending along the accumulator means from its outfeed side back to its infeed side. Apparatus according to claim 12, wherein the apparatus further includes downstream locator means (242), for establishing a stop point relatively just downstream from said accumulator means outfeed side (24) against which queued products are shifted relatively downstream just prior to removal of products from the conveyor belt means (10, 210), whereby adjacent product shear point interaction with a vertical conveyor mechanism vane (20) is prevented.

Inventors: STEEBER DORIAN FRANKLIN, STEEBER, DORIAN FRANKLIN
Applicants: HARTNESS INT INC, HARTNESS INTERNATIONAL, INC.
Application year: 1990
Main classification: B65G47
IPC codes: B65G43, B65G47