Releasable shoe and method for shoe sorter

A sorter conveyor system includes a conveyor forming an upwardly facing support surface for conveying objects. The support surface includes slots oriented transversely to the conveying direction and a plurality of shoe assemblies mounted for sliding movement along respective slots for transversely discharging objects from the conveying surface. Each shoe assembly includes a carrier disposed below the conveying surface, and a shoe disposed above the support surface. The shoe and the carrier together form a releasable connection therebetween. The releasable connection is configured to enable the shoe, in response to an undesirable force applied thereto, to detach completely from the carrier without breakage or failure of any part of the shoe assembly, and to be manually reattached without the use of tools or special skills. Various related methods are additionally disclosed.

FIELD OF TECHNOLOGY

The present disclosure relates to shoe sorters for the conveying and discharging of objects at respective destinations, and in particular to releasable shoes which become disconnected in response to being acted upon by an undesirable external force and related methods.

BACKGROUND

A shoe sorter is a type of sorter conveying system composed of a conveyor which moves in a conveying direction along a conveying route. Mounted on the conveyor are pusher shoes which are movable relative to the conveyor in a direction transversely relative to the conveying direction. Each shoe is coupled to a guide pin or wheel which can engage a guide track mounted beneath the conveying surface for determining the lateral position of the shoe relative to the conveyor surface. The rail arrangement includes diverters which can divert the travel direction of the guide pin or wheel from the conveying direction to a direction oriented transversely relative to the conveying direction. In that fashion, the shoes can push items transversely from the conveyor and onto a chute at appropriate destination sites along the conveying route. Examples of such sorters include U.S. Pat. No. 4,738,347 issued to Brouwer et al on Apr. 19, 1988, U.S. Pat. No. 5,333,715 issued to Sapp on Aug. 2, 1994, and U.S. Pat. No. 5,613,591 issued to Heit et al. on Mar. 25, 1997.

It can occur, however, that backups of objects on the chutes can occur. When that happens, it is possible that the shoes will push subsequent objects toward a blocked chute that does not admit entry of those objects. Accordingly, the shoes may be subjected to considerable undesirable (e.g., above a predetermined acceptable level) external forces that can damage the shoes, the conveyor, and/or the objects being conveyed. Each shoe can be attached by a connector element which fails or breaks in response to the application of the external forces to allow the shoe to detach from its drive pin (e.g., see the connector elements28,228, and260disclosed in U.S. Pat. No. 7,628,265 issued to Verploegen et al. on Dec. 8, 2009; and the connector element14disclosed in U.S. Pat. No. 7,198,145 issued to Brown et al. on Apr. 3, 2007). When that occurs, reattaching the shoe requires that the failed or broken part be replaced and/or the use of tools. Reattachment can also require special knowledge and skills to perform the operation correctly. Such replacement processes can be complicated by the need to obtain replacement parts, tools, etc., which can be time consuming; possibly resulting in appreciable down-time of the sorting conveyor.

SUMMARY

In one aspect of the disclosure, a sorter conveyor apparatus includes an endless upwardly facing conveying surface movable in a conveying direction. The conveying surface is defined by a plurality of surfaces separated by a plurality of slots extending in a transverse direction relative to the conveying direction. A plurality of shoe assemblies, that each include a shoe disposed above the conveying surface and a carrier disposed below the conveying surface. Each of the plurality of shoe assemblies extends through at least one of the slots in the conveying surface to permit each shoe assembly to move in the transverse direction while also moving in the conveying direction with the conveying surface. Each of the shoe assemblies includes a snap-fit connection coupling the shoe and the carrier together. The snap-fit connection has a structure which permits the shoe to detach from the carrier in response to an undesirable force acting on the shoe without damaging any part of the shoe assembly. The snap-fit connection further has a structure that permits the shoe to be fully recoupled to the carrier manually without the use of tools after being detached from the carrier.

In another aspect of the disclosure a sorter conveyor apparatus includes an endless upwardly facing conveying surface movable in a conveying direction. The conveying surface is defined by a plurality of surfaces separated by a plurality of slots extending in a transverse direction relative to the conveying direction. A plurality of shoe assemblies that each include a shoe disposed above the conveying surface and a carrier disposed below the conveying surface. Each of the plurality of shoe assemblies includes a bridge extending through at least one of the slots in the conveying surface to permit each shoe assembly to move in the transverse direction while also moving in the conveying direction with the conveying surface. Each of the shoe assemblies includes a snap-fit connection coupling the shoe and the carrier together. The snap-fit connection includes two connector projections that each include a hook member having a locking surface, and respective cooperating locking surfaces against which one of the hook members is engaged to retain the shoe and the carrier together. Each of the shoe assemblies further includes two drive projections, with each drive projection being received in a cooperating opening to transfer forces between the shoe and the carrier when the shoe is driven in the transverse direction without the shoe detaching from the carrier absent exposure to an undesirable force.

In a further aspect of the disclosure, a sorter conveyor apparatus includes an endless upwardly facing conveying surface movable in a conveying direction. The conveying surface is defined by a plurality of surfaces separated by a plurality of slots extending in a transverse direction relative to the conveying direction. A plurality of shoe assemblies that each include a shoe disposed above the conveying surface and a carrier disposed below the conveying surface. Each of the plurality of shoe assemblies includes a bridge extending through at least one of the slots in the conveying surface to permit each shoe assembly to move in the transverse direction while also moving in the conveying direction with the conveying surface. Each of the shoe assemblies comprising a releasable snap-fit connection coupling the shoe and the carrier together. The releasable snap-fit connection includes a connector projection, and a cooperating connector member upon which the hook members engage to retain the shoe and the carrier together. The shoe assembly comprises a flexible material to bias the connector projection against the cooperating member to increase the force required to detach the shoe.

In yet another aspect of the disclosure, a sorter conveyor method is provided for use with an endless upwardly facing conveying surface movable in a conveying direction. The conveying surface is defined by a plurality of surfaces separated by a plurality of slots extending in a transverse direction relative to the conveying direction. The method includes providing a plurality of shoe assemblies, with each shoe assembly including a shoe disposed above the conveying surface and a carrier disposed below the conveying surface. Each of the plurality of shoe assemblies extends through at least one of the slots in the conveying surface. The method can include coupling the shoe and the carrier together using a snap-fit connection; and causing at least some of the shoe assemblies to move in the transverse direction while also moving in the conveying direction with the conveying surface; Upon exposure to an undesirable force acting upon the shoe, the shoe automatically detaches from the carrier at the snap-fit connection without damaging any part of the shoe assembly, including the snap-fit connection. After such detaching, the method includes fully reattaching the shoe to the carrier manually without the use of tools using the undamaged shoe, including the undamaged snap-fit connection.

DETAILED DESCRIPTION

Exemplary embodiments are disclosed herein, including numerous specific details, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that the specific details need not be employed, that the development described herein may be embodied in many different forms. Neither the embodiment, nor its specific details should be construed to limit the scope of the disclosure. In some cases, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps disclosed herein may be employed in any of the various embodiments discussed herein, regardless of whether such additional or alternative step is expressly disclosed for use in a particular embodiment herein.

Depicted inFIGS. 1-3is an exemplary shoe sorter comprising an endless conveyor for conducting objects A in a conveying direction D past destination sites. The conveyor includes an upwardly facing support surface on which the objects are disposed. The support surface can be formed by support rails15which are connected to roller chain strands12driven in the conveying direction D by any suitable drive mechanism, such as sprockets13driven by a motor14. Each support rail15includes a pair of horizontal portions10that are spaced apart in the direction D to form a slot16extending longitudinally along the rail, i.e., in a direction T transversely of the conveying direction D. Attached to each end of the support rail15can be an insert17(seeFIG. 3) which carries a pair of wheels18arranged to travel on a main frame19of the sorting conveyor.

Mounted on the conveyor are shoe assemblies20, each arranged to travel along a respective rail15in the transverse direction T. Each shoe assembly20includes a carrier22and a shoe24attached thereto (SeeFIG. 5). The carrier22includes a main body26arranged within the rail beneath the horizontal portions10. Projecting downwardly from the main body26is a pin32on which a wheel34can be rotatably mounted.

The shoe24, which can be arranged to slide along a respective support rail, preferably comprises two sections, i.e., a base52mounted to a cover50. As seen in the drawings, it is not necessary that the cover50completely enclose the base52. The cover50, however, is the component intended to be the primary, if not exclusive, component of the shoe assembly that directly contacts objects A on the conveyor. Cover50can be preferably formed of a thermoplastic elastomeric material, such as Santoprene® 201-64, and the base52can be preferably formed of a stiffer material, such as a polyoxymethylene like Delrin® 100ST which is characterized by high mechanical strength and rigidity, long-term fatigue endurance, resilience and resistance to creep. The base52includes a recess54which receives a web portion56of the cover50, preferably by a force fit. The web portion56includes an aperture58formed therein, which becomes situated between lower and upper panels60,62of the base52when the cover52is interconnected therewith. The web portion56can be compressed when inserted into the recess54to create a force or friction fit with the base52. In addition, the elastomeric material of the cover50, and specifically web portion56, operates as a biasing member to bias the lower and upper panels60,62away from one another for reasons to be explained. The cover50further includes a pair of identical end portions63disposed on opposite ends of the web portion56for making direct contact with conveyed objects.

The base52includes a pair of feet64whose end edges65are slidable within respective grooves69formed by hook-shaped portions61of the rail15that extend in the direction T (seeFIG. 3). It will be appreciated that objects being conveyed will rest directly on the tops of the hook-shaped portions which together define the support surface of the conveyor. For that reason, center hook-shaped portions61aare provided midway between the outer hook-shaped portions61, to provide additional support for the objects, but such center hook-shaped portions do not interact with the shoe assemblies, because the shoes include respective recesses50ain which the center hook-shaped portions are disposed.

Each of the lower and upper panels60,62has a set of openings formed therein, i.e., lower openings60a-din the lower panel, and upper openings62a-dformed in the upper panel (seeFIGS. 6-7). The lower openings60a-dare vertically aligned with respective upper openings62a-d.

The main body26of the carrier22, which carrier can also preferably be formed of Delrin®, includes four projections or tabs, namely, a pair of thin, flat upstanding drive projections70a,70b, and a pair of thin, flat upstanding connector projections72a,72bdisposed between the drive projections, as shown inFIG. 7. The four projections70a,band72a,blie in a common plane which contains the respective slot16(seeFIG. 5). The four projections project sequentially upwardly through: the slot16of the respective support rail15, the respective lower openings60a-d, the aperture58formed in the web52, and the respective upper openings62a-d. The shoe assembly can be driven in the transverse direction T by the drive projections70a,b. It will be appreciated that the shoe assemblies are driven in the conveying direction D by the support rails15, due to the engagement of the feet end edges65within the grooves69, whereas the drive projections70a,bonly drive the shoe assemblies in the transverse direction T, thereby enabling the drive projections to be relatively thin.

Each drive projection70a,bincludes opposite vertical surfaces71which engage the edges of a respective upper opening62a,dfor transferring drive forces from the carrier22to the shoe to displace the shoe in either direction along the slot16. The upper end of each drive projection can be beveled to form two surfaces73which are inclined relative to vertical. Each of the drive projections70a,balso includes an upwardly facing shoulder75on which the lower panel60of the base52rests during normal travel of the shoe assemblies.

Each of the connector projections72a,bcan be somewhat elastically flexible in the direction T and has a hook-shaped upper end, with the hooks74thereof pointing toward one another. Each hook74includes a downwardly facing shoulder76operating as a locking surface arranged to engage the upper surface of upper panel62surrounding a respective upper opening62b,coperating as a cooperating locking surface to releasably connect the shoe24to the carrier22. As explained earlier, the lower and upper panels60,62are biased away from one another by the elastic web portion56of the cover50. As a result, the downwardly facing shoulders76operating as a locking surfaces are biased against a respective upper surface of upper panel62operating as a cooperating locking surface and surrounding upper opening62b,c. This biasing arrangement can also operate to bias shoes24down against surface10, which can help insure ends65of feet64of base52are positioned within the grooves69. This biasing arrangement can also tend to urge the carrier upwardly to press the carrier22upwardly against undersides of the horizontal portions10. Thus, the biasing arrangement can reduce rattling as the shoe assemblies move along the support rails15.

Shoulders75associated with the drive projections70a,bcan operate to limit the biasing forces being exerted on shoe24. For example, shoulder75can be positioned to limit how much downward force can be applied to shoe24, thereby limiting the friction created as shoe24slides along the conveying surface10. Shoulders can additionally or alternatively be positioned to increase the locking force pressing the downwardly facing shoulders76or locking surfaces against respective upper surfaces of upper panel62or cooperating locking surfaces. Thus, the biasing arrangement can generate a high locking biasing force at the interface of the locking surfaces associated with the connector projections while generating a much smaller downward force at the interface between shoe24and conveying surface10.

As can be seen fromFIG. 7, each of the openings60b,60c,62band62ccan be of greater width than the section of the respective connector projection72a,72bdisposed therein. In the normal condition of the shoe assemblies, e.g., situated at either side of the conveyor or when objects being pushed transversely by the end portions63of the shoes24, the shoes24have not encountered an undesirable obstruction to movement (such as a jam-up of objects on a discharge chute). In this normal condition, the shoulders76of the hooks74overlie respective surface areas of the upper panel62operating as a cooperating connector member to thereby secure the shoe24to the carrier22.

However, while pushing an object toward a destination, the object may encounter a jam-up of objects, wherein the ends of the shoes pushing the object become subjected to a resistance force F (seeFIG. 4). That force may be of an undesirable magnitude thereby causing the ends of one or more of the shoes to be forced upwardly and cause the hooks of the respective connector projections72a,bto flex elastically, enabling the shoe to become detached from the carrier22, as shown inFIG. 8. The flexibility of the connector projections72a,bensures that such shoe, or shoes, can become completely detached from the carrier22without damaging or breaking any of the parts of the shoe assembly. After the jam-up is removed, the detached shoe(s) can easily be manually reattached to the carrier without requiring the use of any tools by simply positioning the shoe24and pressing downwardly on the shoe24such that the lower panel60passes downwardly along the drive projections70a,baided by the beveled upper ends73of those drive projections. Each hook74can also include an upwardly facing surface78which can be inclined relative to vertical and disposed in downwardly converging relationship with the inclined surface78of an adjacent connector projection. The upper panel62will contact the downwardly converging surfaces78of the connector projections72a,bto elastically spread the connector projections away from one another. That enables the upper panel62to move downwardly past the hooks74, whereupon the connector projections snap back to the state shown inFIG. 7. The upper panel62will also slide down along the drive projections70a,baided by the beveled upper ends73of the drive projections.

It will be appreciated that the carrier's connector-projections72a,band the cooperating connector member in the form of panel62with its upper surface and associated openings62b,ctogether form a releasable connection between the shoe and the carrier which prevents damage occurring to either the shoe or the carrier when the shoe is detached in response to encountering a jam-up of discharging objects. Thus, a detached shoe can be easily reattached manually without the use of tools and without having to replace any damaged or broken parts of the shoe assembly.

Modifications, additions, and subtractions may be made to the exemplary embodiment disclosed above, without departing from the scope of the appended claims. For example, instead of the connector projections being arranged with their hooks74pointing toward each other, the hooks could instead point away from one another, as shown inFIG. 9. Also, even though both the carrier and the shoe's base are disclosed as being formed of an elastomeric material, it is possible that either the carrier or the base could be formed of a stiff material.

Further, alternative releasable connections can be envisioned by one of skill in the art that provide easy manual reattachment without the use of tools and without having to replace any damaged or broken parts of the shoe assembly. Examples of such releasable connections include alternative snap-fit connections that have cooperating protrusions and detents, instead of the cooperating hooks and surfaces expressly disclosed herein.

Various related methods are apparent based on the foregoing discussion. For example, such methods can include providing an endless upwardly facing conveying surface10movable in a conveying direction, wherein the conveying surface10can be defined by a plurality of surfaces separated by a plurality of slots16extending in a transverse direction relative to the conveying direction. The methods can include disposing a shoe24above the conveying surface10and disposing a carrier22below the conveying surface10and coupling the shoe24and the carrier22together to form a shoe assembly20. The disposing and coupling steps can be repeated to form a plurality of shoe assemblies20with each shoe assembly20extending through one of the slots16in the conveying surface10to permit each shoe assembly20to move in the transverse direction while also moving in the conveying direction with the conveying surface10.

The methods can include any of providing the shoe assembly20with a snap-fit connection72a,band62for coupling each shoe24and carrier22together; releasing the snap-fit connection to permit the shoe24to detach from the carrier22without damaging any part of the shoe assembly20in response to an undesirable force acting on the shoe24; and manually reconnecting the snap-fit connection to permit the shoe24to be fully recoupled to the carrier22without the use of tools after being detached from the carrier22.

The methods can include any of providing the snap-fit connection with one, two, or more connector projections72a,bthat can each include a hook member74that can have a locking surface76; and providing respective cooperating locking surfaces62(adjacent openings62b,c) which the hook member74locking surfaces76engage flat against to retain the shoe24and the carrier22together.

The methods can include any of providing each of the shoe assemblies20with one, two, or more drive projections70a,b; coupling the shoe24and the carrier22together to cause each drive projection70a,bto be received in a cooperating opening62a,dand60a,dto transfer forces between the shoe24and the carrier22when the shoe can be driven in the transverse direction without the shoe24detaching from the carrier22unless the shoe is exposed to an undesirable force; providing the connector members72a,b, the drive projections70a,b, or both as thin members having major surfaces extending in the transverse direction; providing a drive projection70a,badjacent a connector projection70a,bso that the projections are aligned in a common plane; and aligning the common plane with a corresponding slot16of the endless conveying surface10.

The methods can include any of flexing the shoe assembly20while coupling the shoe24and carrier22together to bias the connector projection72a,bagainst the cooperating member62to increase the force required to detach the shoe24from the carrier22; providing the connector projection72a,bas a locking surface76which can be part of a hook member74; providing the cooperating member62as a cooperating locking surface which can be adjacent an opening62b,c. Biasing a flat locking surface76flat against respective flat cooperating locking surface62which can increase the force coupling the shoe24and the carrier22together; and flexing the shoe assembly20while coupling the shoe24and carrier22together to bias the locking surface76against the cooperating locking surface62to increase the force required to detach the shoe24from the carrier22.

The methods can include any of providing the endless conveying surface10with a groove69extending in the transverse direction formed by a hook-shaped portion61extending in one of the conveying direction and an opposite direction to the conveying direction; providing the shoe24with a cooperating edge65, capturing the cooperating edge65within the groove69formed by the hook-shaped portion61; providing the endless conveying surface10with an other opposing groove69extending in the transverse direction formed by a hook-shaped portion61extending in the other of the conveying direction and an opposite direction to the conveying direction; providing each shoe24with an other, opposing cooperating edge65; capturing the other cooperating edge65with the other hook shaped portion61; sliding the edges65along the grooves69; and flexing the shoe assembly20while coupling the shoe24and carrier22together, which can bias the shoe24against the conveying surface10and can facilitate one or both of the edges65being captured within the respective grooves69.

The methods can include any of assembling the shoe24from a base52and a cover50disposed above the conveying surface10; positioning the snap-fit connection to detach both the base52and cover50from the carrier22in response to the undesirable force acting on the shoe24; providing one, two, or more of the connecting projections72a,b, and one, two, or more of the drive projections70a,b, which can be positioned to extend from the carrier22through one of the plurality of slots16above the conveying surface10; visually identifying the location of a carrier22under the conveying surface10from which a shoe24has detached by visually locating the connector projections72a,b, drive projections70a,b, or both that extend above the conveying surface10; and using the connector projections72a,b, drive projections70a,b, or both that extend above the conveying surface10to position the shoe24correctly above the carrier22for reattachment, prior to reattaching the shoe24to the carrier22.

The methods can include any of assembling the shoe24from a base52and an elastomeric cover50for directly contacting objects being conveyed; press-fitting the elastomeric cover50between a lower panel and an upper panel of the base52, which can result in biasing the upper panel62and the lower panel60away from each other; providing the upper panel62with one of the connector projection72a,band the cooperating connector member62; providing the carrier24with the other of the connector projection and the cooperating connector member positioned to resist the bias of the shoe24; and forming the shoe24from polyoxymethelene; and forming the base52of the shoe24from polyoxymethylene.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements, features, or steps of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in other embodiments, even if the resulting combination is not specifically illustrated or described herein. The same may also be varied in any way as to the inclusion or not of other individual elements, features, or steps. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.