WO2005076906A2

WO2005076906A2 - Conveyor for a high speed diverter system and related article carrier

Info

Publication number: WO2005076906A2
Application number: PCT/US2005/003497
Authority: WO
Inventors: James L. Layne; Michael D. Mcdaniel; Stephen C. Fye; Keith B. Thomas; Lewis W. Ward
Original assignee: Span Tech Llc
Priority date: 2004-02-05
Filing date: 2005-02-04
Publication date: 2005-08-25
Also published as: WO2005076906A3

Abstract

In one aspect, the present invention relates to a conveyor for intended use in a diverter system. The conveyor comprises a pair of spaced conveyor chains formed of links having a depending arm with an inwardly projecting guide tab. The links are secured together by connector rods creating opposed inward projections that support a first carrier rod positioned between the chains. Another aspect of the invention is an article carrier for capturing a first carrier rod, but releasably connecting with a second, adjacent carrier rod. Consequently, the carrier upon release from the second carrier rod can bodily move and pivot about the first carrier rod, such as in the event a portion of the carrier encounters an obstruction. The carrier may also include article-engaging projections.

Description

CONVEYOR FOR A HIGH SPEED DIVERTER SYSTEM AND RELATED ARTICLE CARRIER

Technical Field The present invention relates generally to article diverter systems and, more particularly, to a conveyor and article carrier for use in such systems.

Background of the Invention Systems capable of diverting conveyed articles are well known. The typical arrangement includes a conveyor associated with a plurality of carriers for supporting the articles. As the conveyor moves in an endless path, an adjacent guide track engages a guide associated with the carrier. In the usual mode of operation, this engagement causes the carrier and the associated article to move laterally along the conveyor. Using such an arrangement advantageously allows for selective placement of the articles into multiple rows or lanes, as necessary or desired for a downstream operation, or alternatively may simply divert selected articles to a takeaway conveyor for further processing. Typically, pairs of transverse carrier rods extend between spaced chains running in parallel and support the carrier such that it is capable of sliding to and fro. In addition, the rods also serve to interconnect the links and form the chain. When using conventional link chains, the rods usually have a relatively small gauge, which may serve as a limiting factor on the capacity of the conveyor. Moreover, increasing the size of the rods is not easily done, absent a corresponding adjustment in the size of the associated links. Typical chains are also not captured and are thus susceptible to undesirable lifting if the carrier rods are made too long or heavy. Another prevalent limitation is that the conveyor often moves at a relatively high speed to achieve the most efficient operation possible. During such high speed operation, the guide associated with each carrier sometimes engages an obstruction, especially in making the transition from a main portion to an auxiliary portion (branch or spur) of the guide track for effecting the desired diversion. Since the conveyor still moves the carrier forward in this situation, a catastrophic failure of the carrier may result, requiring deleterious downtime to make the necessary repair. This downtime not only increases the maintenance expense, but also the expense associated with a concomitant loss in production while completing the appropriate repair operation. Accordingly, a need is identified for one or more diverter systems with conveyors addressing and overcoming the foregoing limitations. Summary of the Invention In accordance with one aspect of the invention, a conveyor for intended use in a diverter system having first and second spaced guide rails is disclosed. The conveyor includes a first conveyor chain comprised of first links interconnected by a first connector having an inwardly projecting end. At least one of the first links includes at least one depending arm and inwardly extending tab for engaging the first guide rail. The conveyor also includes a second conveyor chain comprised of second links interconnected by a second connector having an inwardly projecting end opposing the inwardly projecting end of the first connector. At least one of the second links includes at least one depending arm carrying an inwardly extending guide tab for engaging the second guide rail. A first carrier support for positioning between the chains is also provided. The first carrier support has a first end adapted for receiving at least a portion of the inwardly projecting end of the first connector. The first carrier support also includes a second end adapted for receiving at least a portion of the inwardly projecting end of the second connector. The conveyor may also include a second carrier support supporting the carrier. The inwardly projecting ends of the first and second connectors may support the carrier supports. A carrier associated with at least the first carrier support is also provided. The carrier may Include at least one opening for receiving the first carrier support, and when associated with the second carrier support, at least one receiver for receiving and connecting with the second carrier support in a snap-fit fashion. In one embodiment, the carrier includes a guide for guiding the carrier. Engagement between the guide and an obstruction may cause the receiver to release from the second carrier support and bodily move and pivot about the first carrier support. In accordance with another aspect of the invention, a method of preventing catastrophic damage to an article carrier in a diverter conveyor system is disclosed. The method comprises capturing a carrier on a first carrier rod and releasably securing the carrier to a second carrier rod. The carrier may release from the second carrier rod to bodily move and pivot about the first carrier rod upon encountering an obstruction.

Brief Description of the Drawings Figure 1 is a partial top cutaway view of one embodiment of a diverter system forming one aspect of the present invention; Figure 2 is a top view of one embodiment of a chain of the diverter system of Figure 1 ; Figure 2a is a top view of one embodiment of a link of the chain of Figure 2; Figure 2b is a perspective view of one embodiment of the link of Figure 2; Figure 3 is a front sectional view of the diverter system of Figure 1; Figure 4a is a sectional rear view of a side portion of the link of Figure 2b; Figure 4b is a sectional side view of a side portion of the link of Figure 2b; Figure 4c is a side view of a locking tab; Figure 4d is a front view of the locking tab of Figure 4c; Figure 5a is a bottom perspective view of one embodiment of a carrier of the diverter system of Figure 1; Figure 5b is a perspective view of the base of the carrier of Figure 5a; Figure 5c is a side view of the carrier of Figure 5a; Figure 6a is a bottom perspective view of a carrier having an additional base; Figure 6b is a perspective view of the additional base of Figure 6a; Figure 6c is a side view of the additional base installed on the carrier of Figure 6a; Figure 6d is a perspective view of the carrier of Figure 6a showing disengagement of a receiver; Figure 7a is a top view of one embodiment of a carrier having article engaging projections; Figure 7b is a rear view of the carrier of Figure 7a; and Figure 7c is a top view of one embodiment of a carrier having article engaging projections.

Detailed Description of the Invention Reference is now made to Figure 1 , which illustrates a diverter system 10 forming one aspect of the present invention. The system 10 as shown includes a driven conveyor (motor and sprockets not shown) comprised of a first endless conveyor chain 12, a second endless conveyor chain 14 spaced from the first chain, a carrier support in the form of a rod 16 positioned between the chains 12, 14, and an associated carrier 18 for supporting or engaging the article(s) being conveyed. As outlined further in the description that follows, the carrier 18 is capable of moving relative to the carrier rod 16 in a direction transverse to the conveying direction C in response to the influence of an externally applied force in order to divert articles transversely across the conveying surface (such as for forming lanes on a downstream conveyor, or for moving selected articles onto an associated takeaway conveyor (not shown)). As shown in Figure 2, the chains 12, 14 are comprised of a plurality of interconnected links 20 arranged in longitudinally spaced rows, R„ R₂ and R₃. The basic structure of the links 20 shown in Figures 1 and 2 is set forth in U.S. Pat. No. 5,031,757, the disclosure of which is incorporated herein by reference. As explained therein, each link 20 includes an apex portion 22 and a pair of leg portions 24 extending from each apex portion, preferably in a diverging relationship. As shown in Figure 2a, the apex portion 22 includes an opening, such as a slot 26, adapted to receive a transverse connector, such as a connector rod 28. Each leg portion 24 includes a transverse hole 25 for receiving the connector rod 28. The holes 25 of the leg portions 24 and the slots 26 of the apex portions 22 are substantially coaxial when two links 20, spaced in the conveying direction C (as shown by the direction arrow of Figure 2), are interdigitated. To interconnect adjacent links 20, the connector rod 28 passes through the slot 26 in each apex portion 22 and the hole 25 in each leg portion 24. Consequently, by repeating this operation, the rows R„ R₂ and R₃ are created and, ultimately, an endless chain 12, 14 is formed. With reference to Figures 2a and 4a-4d, each link 20 includes first and second side portions 30. Each side portion 30 includes a depending arm 32 for locating and guiding the conveyor chain 12, 14 along a cooperating guide track 33 formed of generally opposed guide members 33a, 33b (which as described in the '757 patent may include wear strips for forming a reduced-friction guide surface for each chain). The depending arms 32 also include inwardly extending tabs 34 to further assist in fully retaining each chain 12,14 on the corresponding guide track 33, especially along the return run. Both of the side portions 30 include holes 36 co-axial with the hole 25 formed in each leg portion 24. These holes 36 receive the connecting rod 28, and at least one leg portion 24 includes an integral locking tab 38 for insertion within a slot 40 formed in the link 20. The locking tab 38 may include prongs 42 for engaging a corresponding circumferential notch 44 provided at one end of the connector rod 28. In the preferred embodiment, the locking tab 38 is fabricated from a resilient or flexible material, such as nylon. This construction allows the prongs 42 of the tab 38 to snap lock in the notch 44 for secure engagement and further allows the locking tab to be easily installed and removed. The locking tab 38 may also include an offset release button 46 seated in an open-ended portion of the slot 40. The button 46 of locking tab assists in the installation and removal of the locking tab 38 from the side portion 30 when, for example, maintenance and repair is required. More specifically, a blade tool, such as a screwdriver, is tapped against the button 46 to initiate prying action. Once sufficient movement is initiated, the screwdriver then provides increased leverage to facilitate removal of the tab. The inherent resiliency of the tab 38 allows the prongs 42 to disengage from the notch 44. To reinsert the tab 38, the prongs 42 are directed into the slot 40. It can be appreciated that the resiliency of the tab 38 allows the prongs 42 to snap around the notch 44. Thus, secure retention of the connector rod 28 results. Alternatively, instead of only the one side portion 30 containing the locking tab 38 arrangement, both side portions may include locking tabs. As shown in Figure 2a, the link 20 may comprise a single structure having plurality of leg 24 and apex portions 22, or instead may comprise a single structure having a single apex portion 22 with two legs 24 and corresponding depending arms/inwardly projecting guide tabs (see, e.g., Figure 2b and U.S. Patent No. 6,202,834, the disclosure of which is incorporated herein by reference). Alternatively, each link 20 may be formed of a plurality of laterally repeating sections (not shown), each having an apex portion and two legportions (see, e.g., U.S. Patent No.4,953,693, the disclosure of which is incorporated herein by reference). In accordance with a first aspect of the invention, each connector rod 28 is preferably adapted for engaging and supporting at least one of the carrier rods 16, which in turn supports an article carrier 18. In the embodiment shown in Figures 2 and 3, this is accomplished by making the connector rods 28 of sufficient length such that one end 50 of each extends through the hole 25 in the inner leg portion 24 of at least one link 20 forming part of each chain 12, 14. This extended end 50 thus projects inwardly from an inside face of the corresponding link 20. As perhaps best shown in Figure 3 and 6d, this extended end 50 of each connector rod 28 is adapted for insertion in a corresponding recess 52a, 52b formed in each end of the carrier rod 16. In particular, the extended end 50 has a diameter D, (see Figure 2) and each recess 52a, 52b has a diameter D₂ that matches or is greater than the diameter D,. As a result, the extended end 50 fits in the recess 52a, 52b of the carrier rod 16. The carrier rod 16 is thus captured between the chains 12, 14, with full support being provided by the extended ends 50 of the connector rods 28, while the chains are in turn captured on the guide rail 33. As should be appreciated, this arrangement allows for the use of conventional connector rods 28 with the links 20 in combination with a carrier rod 16 having a greater load handling capability (e.g., with a larger diameter) and links 20 that capture the chains 12, 14. The requirement for small diameter connector rods 28 used with non-captured chains is thus no longer a limitation on the capacity of the diverter system 10 incorporating such a conveyor. In other words, a carrier rod 16 of increased strength maybe used with the connector rods 28 and the captured chains 12, 14 to thus enhance the capacity of the diverter system 10. Moreover, in the case of a carrier rod 16 having an increased diameter, it can be made longer than would normally be possible to increase the size of the conveying surface (which may allow for more lanes to be formed) without compromising the strength of the resulting conveyor and without undesirable lifting of the chains 12, 14. Not only does this result in an improvement in performance, especially where relatively large or heavy articles are conveyed, but also an increase in the service life of the system 10. In accordance with another aspect of the invention, and with reference now to Figures 5a-5c, the conveyor system 10 may further include making improvements to the carrier 18 for assisting in supporting articles during conveyance. As shown, the carrier 18 in the illustrated embodiment includes a carrier plate 58 and a separate base 60. The base 60 fastens to the plate 58 via standard mechanical fasteners (e.g., screws 66) or otherwise. Alternatively, the base 60 and the carrier plate 58 may comprise a one-piece structure. The base 60 includes a receiver 62 for releasably receiving and connecting with a first carrier rod 16 (see, e.g., rod 1 a in Figure 6d). Preferably, the arrangement is such that the receiver 62 snaps over the carrier rod 16 (which is typically cylindrical with a smooth outer surface), but does not prevent the carrier 18 itself from undergoing the desirable movement (usually sliding) in the course of diverting the articles being conveyed. As perhaps best shown in Figures 5b-5c, this may be accomplished by proving a protrusion 68 in the receiver 62 that thus creates a passage of width W₃ less than the diameter of the associated carrier rod 16. This of course creates a neck through which the rod must pass to non-permanently associate and releasably connect it with the carrier 18. The base 60 further includes an opening 64 defining a channel for receiving and capturing a second carrier rod 16 (rod 16b in Figure 6d) spaced from the first carrier rod 16 in the longitudinal or conveying direction C. Preferably, the opening 64 is generally U-shaped and is slightly wider than the diameter D₃ of the carrier rod 16 (note dimension W₂). This of course permits the associated carrier rod 16 to pass through the opening 64 such that the carrier 18 is capable of moving to and fro, as is necessary for effecting the desired diversion of the associated article. As should be appreciated, the engagement between the adjacent surface of the base 60 and the upper surface of the carrier rod 16 typically is of the desirable sliding type. The receiver 62 and opening 64 are also spaced apart so as to match the spacing of the associated carrier rods 16, which is typically maintained constant for a given conveyor. With reference to Figures 5b and 5c, the base 60 associated with the carrier 18 typically includes a depending member, such as a wedge-shaped guide 70, adapted for following a guide track 56 associated with the diverter system 10 (and typically below the conveying surface; see Figure 1 ). An actuator (not shown) along the guide track 56 selectively engages the guide 70 to direct the carrier 18 to an auxiliary branch 56b (as opposed to a "pass through" track 56a, which if followed would not result in the diversion of the carrier or associated article in the illustrated embodiment). In the case the guide 70 is guided into the auxiliary track 56b, an article associated with the carrier 18 is diverted accordingly. Although Figures 5b-5c shows the carrier 18 with only one base 60, it may include an additional or second base 72 for possibly engaging the corresponding carrier rod 16 and providing additional support for the carrier 18 (such as when using an extended length carrier-see Figures 6a- 6d). When present, this base 72 includes an opening 64 and may attach to the carrier plate 18 as previously described. The second base 72 includes a receiver 62, but need not include any protrusion or like structure. Rather, the receiver 62 simply provides a surface (preferably matching) for resting on the upper surface of the associated carrier rod 16. Figure 6d illustrates the manner in which the receiver 62 associated with a first carrier rod 16a advantageously becomes automatically disengaged in the event of an undesirable collision between the carrier 18 and an external structure. If for example the guide 70 engages an obstruction or a portion of the guide track 56 (such as sometimes occurs due to a mis-switch/malfunction of the actuator during high-speed operation, but may also result from a simple misalignment, regardless of the conveying speed), the attachment of the carrier 18 to the first carrier rod 16a permits the carrier 18 to bodily move and pivot from a mounted position A substantially captured on the second carrier rod 16 to a disengaged position B (see Figure 6d) in a "pop-up" fashion. In particular, with the conveyor moving in the conveying direction C, any significant force applied to the guide 70 in the opposite direction results in the release and bodily movement of the carrier 18 about the second carrier rod 16b in generally the same direction (i.e., forward). This disengagement moves the guide 70 out of the path of the obstruction (and as shown in Figure 6d, possibly above the conveying surface). As a result, the conveyor is allowed to proceed along the conveying path, thereby avoiding an otherwise catastrophic event. Although the article may be ejected from the conveyor during the pop-up sequence, the carrier 18 may be simply returned to the mounted position, either manually or automatically by structure (e.g., a roller (not shown)) mounted adjacent to the conveyor, such as along the return run. In accordance with yet another aspect of the invention, the carrier 18 may further include article-engaging projections. For example, as shown in Figures 7a and 7b, a plurality of projections 80 in the form of spaced ribs or cleats may be integrally formed in the surface of the plate 58 attached to the base 60. Preferably, the projections 80 are elongated and generally align with the conveying direction C. Thus, the projections 80 may interleave with the fingers on a transfer (bridge, comb, or like structure) at either end of the conveyor (note channels between spaced projections). This allows the carrier 18 to potentially engage or deposit an article on an upstream or downstream transfer, respectively. Alternatively, as shown in Figure 7c, one or more pairs of angled projections 82 may also be provided. As shown, these projections 82 may converge in the conveying direction C. The angled projections 82 are especially useful in arrangements where the associated articles are relatively small in size. The carrier 18 and links 20 may be formed of any durable material, with UHMW polyethylene, polypropylene or Acetal being preferred choices because of the high durability, relatively low weight, and low cost of such materials. The connector rods 28 and carrier rods 16 are preferably fabricated from stainless steel, with one having a diameter of about two times the other or greater. Using these materials results in a substantially strong chain and one not prone to oxidation and rust. However, the links, carrier, connector rods, and carrier rods may be formed of any material, including metal or other polymers, without limitation. The foregoing descriptions of various embodiments of the invention are provided for purposes of illustration, and are not intended to be exhaustive or limiting. Modifications or variations are also possible in light of the above teachings. For example, while shown only extending a small portion of the length L of the carrier rods 16, the first and second recess 52a, 52b may extend any distance through the length L of the carrier rods 16, and may even comprise continuous channel. Additionally, the extended portion 50 of the connector rods 28 may also comprise any length corresponding to the length of the first and second recesses 52a, 52b. Moreover, a skilled artisan will appreciate that, instead of using the connector rods 28 to create the extended end 50, one may form the links of the first and second conveyors chains to include a projecting pin or other extension for engaging the carrier rod 16 (although this is considered less desirable from a cost standpoint). It is also possible to provide the connector rods 28 for interconnecting adjacent links 20 forming one or both of the chains 12, 14 on the carrier rod 16 itself. The embodiments described above were chosen to provide the best application to thereby enable one of ordinary skill in the art to utilize the disclosed inventions in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention.

Claims

In The Claims 1. A conveyor for intended use in a diverter system, comprising: a first conveyor chain; a second conveyor chain; first and second carrier rods positioned between said first and second conveyor chains; and a carrier including at least one opening for receiving the first carrier rod, at least one receiver for receiving and connecting with the second carrier rod in a snap-fit fashion, and a guide for guiding the carrier; whereby engagement between the carrier, and an obstruction may cause the receiver to release from the second carrier rod and bodily move and pivot about the first carrier rod.

2. The conveyor of claim 1 , wherein the opening receives the first carrier rod such that the carrier may slide to and fro in a direction transverse to a conveying direction.

3. The conveyor of claim 2, wherein the receiver includes a protrusion defining a neck through which the second carrier rod passes

4. The conveyor of claim 3, wherein the second carrier rod has a dimension D„ the neck has a corresponding dimension D₂, and D^D^

5. A conveyor for intended use in a diverter system having a first and second spaced guide rails, comprising: a first conveyor chain comprised of first links interconnected by a first connector having an inwardly projecting end, at least one of said first links having at least one depending arm and inwardly extending tab for engaging the first guide rail; a second conveyor chain comprised of second links interconnected by a second connector having an inwardly projecting end opposing the inwardly projecting end of the first connector, at least one of said second links having at least one depending arm carrying an inwardly extending tab for engaging the second guide rail; and a first carrier support for positioning between the chains, said carrier support having a first end adapted for receiving at least a portion of the inwardly projecting end of the first connector and a second end adapted for receiving at least a portion of the inwardly projecting end of the second connector; whereby the inwardly projecting ends of the first and second connectors support the carrier support.

6. The conveyor of claim 5, further including a second carrier support supporting the carrier.

7. The conveyor of claim 6, further including a carrier having a receiver for receiving and releasably connecting with the second carrier support in a snap-fit fashion, whereby the engagement between the carrier and an obstruction may cause the receiver to release from the second carrier support.

8. The conveyor of claim 7, wherein the first carrier support is captured in an opening formed in the carrier, whereby the carrier bodily moves and pivots about the first carrier support upon release therefrom.

9. The conveyor of claim 5, wherein the first carrier support has a diameter at least about two times greater than a diameter of the first connector.

10. The conveyor according to claim 5, wherein each of the first and second links includes a pair of depending arms, each including an inwardly extending tab for engaging the corresponding guide rail.

11. A carrier for intended use in a diverter system including first and second conveyor chains, with first and second carrier rods between the chains, comprising: a body including at least one opening for receiving the first carrier rod, at least one receiver for receiving and connecting with the second carrier rod in a snap-fit fashion, and a guide for guiding the carrier; whereby engagement between the guide and an obstruction may cause the receiver to release from the second carrier rod and bodily move and pivot about the first carrier rod.

12. The carrier of claim 11 , wherein the body comprises a plate for supporting the articles and the opening and receiver are formed in a base attached to the plate by a fastener.

13. The carrier of claim 11 , further including a pair of spaced openings for receiving the first carrier rod.

14. A conveyor for intended use in a diverter system, comprising: a first conveyor chain; a second conveyor chain; first and second carrier rods positioned between said first and second conveyor chains and spaced apart in a conveying direction; and a carrier including at least one channel for receiving and capturing the first carrier rod, at least one receiver for receiving and releasably connecting to the second carrier rod, and a guide for guiding the carrier; wherein engagement between the guide and an obstruction may cause the receiver to release from the second carrier rod and bodily move and pivot about the first carrier rod.

15. A method of preventing catastrophic damage to an article carrier in a diverter conveyor system including a pair of carrier rods spaced apart in the conveying direction, comprising: capturing a carrier on a first of the carrier rods; releasably securing the carrier to a second of the carrier rods; whereby the carrier may release from the second carrier rod upon encountering an obstruction.

16. The method of claim 15, wherein the capturing and securing is such that the carrier may freely move to and fro in a direction transverse to a conveying direction.

17. A conveyor for intended use in a diverter system, comprising: first and second spaced conveyor chains for moving in a conveying direction; first and second carrier rods positioned between said first and second conveyor chains; and a carrier supported by the first and second rods, the carrier including abase adapted for receiving one of said rods and a plate supported by the base having a plurality of spaced projections for engaging and supporting an article being conveyed.

18. The conveyor according to claim 17, wherein the projections are elongated in a direction generally aligned with the conveying direction.

19. The conveyor according to claim 17, wherein the projections are elongated in a direction at an angle to the conveying direction.

20. The conveyor according to claim 17, wherein the projections define channels, each adapted for receiving a projection on a transfer positioned at an upstream or downstream end of the diverter system.

21. The conveyor according to claim 17, wherein the base is captured on one of the carrier rods and releasably receives the other of the carrier rods, whereby engagement with an obstruction may causes the carrier to release, bodily move, and pivot about the captured carrier rod.