Split sprockets for use in conveyor systems

A split sprocket for use in a modular conveyor belt is disclosed. The split sprocket includes first and second portions that may be selectively arranged in a first configuration in which the sprocket maintains a fixed axial position on the shaft and a second configuration in which the sprocket can axially float along the shaft.

FIELD OF THE DISCLOSURE

The field of the disclosure relates generally to sprockets for use in a conveyor systems and, more particularly, to split sprockets for use in a modular conveyor belt system in an industrial food processing system.

BACKGROUND

A modular conveyor belt system is typically driven by a rotating shaft with a plurality of sprockets positioned along the length of the shaft. As the shaft rotates, the teeth along the circumferential surface of each sprocket mate with the underside of the belt modules to propel an article along the belt's length. At least one sprocket is secured to the shaft with shaft collars to maintain the belt's alignment. Other sprockets are allowed to float along the length of the shaft to adapt to thermal expansion of the belt as needed.

In many such applications, each sprocket is configured as a single piece with a bore through its center, such that the sprocket can only be installed or removed by removing the entire shaft to slide the sprocket on or off an end of the shaft. Other sprockets are configured as two semicircular halves that are held together with a clamp, bolts, or other hardware. Such embodiments, known as split sprockets, can be added or removed from the conveyor belt system without removing the shaft from the assembly.

Conveyors used in food processing applications are typically designed to allow the conveyer components to be sanitized. To avoid cross-contamination or other sanitation issues, conveyor systems and components are often designed without any holes or crevasses that can harbor bacteria. Alternatively, parts may be designed for easy disassembly such that all surfaces, including those with no direct contact with food products, are accessible for thorough cleaning.

In many “wet” food industries, such as meat and dairy, equipment may be disassembled for cleaning as often as every shift. Extensive disassembly procedures can make the shift change process cumbersome and inefficient.

There is a need for a split sprocket that can be quickly and easily removed from a conveyor for cleaning and/or that may be arranged in a first configuration in which the sprocket is axially fixed in position relative to the shaft and a second configuration in which the sprocket may float along the shaft.

SUMMARY

One aspect of the present disclosure is directed to a split sprocket having a rotational axis. The split sprocket includes first and second sprocket portions. The first sprocket portion has first and second sides. A mid-plane is parallel to the first and second sides and extends through the first sprocket portion. The first sprocket portion includes a first circumferential outer surface for engaging a belt. The first circumferential outer surface has first and second ends and a center line midway between the first and second ends. The center line is parallel to the rotational axis. The first sprocket portion includes a center plane perpendicular to the mid-plane. The rotational axis and center line are contained in the center plane. The first sprocket portion includes a first mating face. The first mating face has a first protrusion and a first recess. The first recess is disposed (1) across the mid-plane and opposite from the first protrusion or (2) across the center plane and opposite the first protrusion. The second sprocket portion has first and second sides. A mid-plane is parallel to the first and second sides and extends through the second sprocket portion. The second sprocket portion includes a second circumferential outer surface for engaging a belt. The second circumferential outer surface has first and second ends and a center line midway between the first and second ends. The center line is parallel to the rotational axis. The second sprocket portion includes a center plane perpendicular to the mid-plane. The rotational axis and center line are contained in the center plane. The second sprocket portion includes a second mating face. The second mating face has a second protrusion and a second recess. The second recess is disposed (1) across the mid-plane and opposite from the second protrusion or (2) across the center plane and opposite the second protrusion.

Another aspect of the present disclosure is directed to a split sprocket for engaging a belt. The split sprocket includes first and second sprocket portions. The first sprocket portion has a first circumferential outer surface. The first circumferential outer surface includes first and second ends. The first sprocket portion has a first mating face that extends between the first and second ends of the first circumferential outer surface. The first sprocket portion includes a first notch for receiving a shaft. The second sprocket portion includes a second circumferential outer surface. The second circumferential outer surface includes first and second ends. The second sprocket portion has a second mating face that extends between the first and second ends of the second circumferential outer surface. The second sprocket portion includes a second notch for receiving the shaft. The split sprocket may be assembled in (1) a first configuration in which the first and second notches form a first sprocket opening for receiving the shaft and (2) a second configuration in which the first and second notches form a second sprocket opening for receiving the shaft. A width of the second sprocket opening exceeds a width of the first sprocket opening.

DETAILED DESCRIPTION

A conveyor system100comprising a conveyor belt10that rotates about a drive assembly12and tail assembly14is shown inFIG.1. The conveyor belt10may be “modular” having sections that are connected together by pins. In other embodiments, the belt is not modular (i.e., is a continuous belt). The conveyor system100includes one or more sprocket assemblies200(FIG.2). The sprocket assembly200may be used as at least one of the drive assembly12and the tail assembly14. In some embodiments, both the drive assembly12and tail assembly14includes a sprocket assembly200. Alternatively or in addition, one or more sprocket assemblies200may be disposed between the drive assembly12and the tail assembly14. In other embodiments, no sprocket assemblies200are disposed between the drive assembly12and tail assembly14(e.g., the conveyor system100includes slider pans or one or more rails and not sprockets between the drive assembly12and tail assembly14).

Each sprocket assembly200includes a shaft16with at least one split sprocket20positioned along its length. The shaft16extends through the split sprocket20. The shaft16may be made of stainless steel or other similar material. In some embodiments, the shaft16has a square cross-section, but its cross-section may also be a circle, a polygon with an even number of sides, or any shape that allows the conveyor system to function as described herein.

Generally, any number of split sprockets20may be positioned along the length of the shaft16(e.g., 2, 3, 4, 6, 8, 10 or more). The distance between sprockets20may be determined based on the load carried by the belt10. Each split sprocket20may be either secured to the shaft in a fixed axial position or is capable of sliding along its length. In an exemplary embodiment, at least one split sprocket20is in a fixed position, and all other split sprockets20are allowed to “float” along the length of the shaft16. Generally any number of split sprockets20may be in the fixed position (one, two, three or more). The sprockets20may be made of plastic, metal (e.g., stainless steel) or any other material that allows the conveyor system100to function as described herein. In some embodiments of the present disclosure the split sprockets are made of stainless steel.

Referring now toFIG.3, each split sprocket20comprises a first sprocket portion210, a second sprocket portion220, and a clamp32(FIG.4) that secures the two sprocket portions210,220together. In some embodiments, the clamp32is a toolless clamp, but the split sprocket20may also be configured with a clamp that is fastened by tools. Referring now to FIG.6, the clamp32is a sanitary clamp and, in particular, a toggle sanitary clamp. Another embodiment of the clamp32is shown inFIG.17. The clamp32illustrated inFIG.17is a square clamp that it tightened by a fastener34(i.e., the clamp is flexible which enables it to be tightened). In other embodiments, different clamp designs (including embodiments having more than one clamp) may be used such as a hose clamp, split shaft collar, hinged shaft collar or standard sanitary clamp may be used. When assembled (i.e., clamped), the first and second sprocket portions210,220form a split sprocket20configured to engage with the conveyor belt10. The split sprocket20rotates about a rotational axis160(FIG.4)

In the illustrated embodiment, the first and second sprocket portions210,220are identical. In other embodiments, the first and second sprocket portions210,220have one or more different features. The single sprocket portion shown inFIG.7may be either of the first and second sprocket portions210,220. Each sprocket portion210,220has a first side234and a second side236. A mid-plane180(FIG.9) parallel to the first and second sides234,236extends through the sprocket portion210,220.

The first sprocket portion210(FIG.3) includes a first sprocket wheel segment244and a second sprocket wheel segment246. Each wheel segment244,246has teeth260for engaging the belt10(FIG.1). The first sprocket wheel segment244is across the mid-plane180(FIG.9) from the second sprocket wheel segment246. A first hub segment340connects the sprocket wheel segments244,246.

Similarly, the second sprocket portion220includes a third sprocket wheel segment254and a fourth sprocket wheel segment256with both segments254,256having teeth260for engaging the belt10(FIG.1). The third sprocket wheel segment254is across the mid-plane180(FIG.9) from the fourth sprocket wheel segment256. A second hub segment350(FIG.5) connects the sprocket wheel segments254,256. As described further below, each first and second sprocket wheel segments244,246mates with either the third or fourth sprocket wheel segment254,256to form a first sprocket wheel270(FIG.5) and a second sprocket wheel280.

The first sprocket portion210has a first sprocket portion notch310and the second sprocket portion220has a second sprocket portion notch320. As described further below, when the split sprocket20is assembled, the notches310,320together form a sprocket opening for receiving the shaft16(FIG.2).

The first sprocket portion210includes a first circumferential outer surface212and the second sprocket portion220includes a second circumferential outer surface222for engaging the belt10(FIG.1). The circumferential outer surfaces212,222include teeth260for engaging the belt10. In the illustrated embodiment, the circumferential outer surface also includes tabs264perpendicular to the teeth260to maintain alignment of the belt10. Each circumferential outer surface212,222includes a first end224, a second end226, and a center line150(FIG.8) midway between the first and second ends224,226along the circumferential outer surface212,222. The center line150is parallel to the rotational axis160, and both the center line150and the rotational axis160are contained in a center plane190(FIG.9) perpendicular to the mid-plane180.

The first sprocket portion210includes a first mating face214that extends between the first and second ends224,226of the first circumferential outer surface212(i.e., the first mating face214defines a chord that extends between the first and second ends224,226of the first circumferential outer surface212). Similarly, the second sprocket portion220includes a second mating face216that extends between the first and second ends224,226of the second circumferential outer surface222(i.e., the second mating face216defines a chord that extends between the first and second ends224,226of the second circumferential outer surface222). A neutral plane170(FIG.9) is parallel to the mating face214,216and may be coincident with a major surface225(FIG.10) of the mating face214,216. With reference toFIG.7, in the illustrated embodiment, each mating face214,216does not extend continually between the first and second ends224,226of the circumferential outer surface212,222. Each mating face214,216is divided into two portions separated by the respective notch310,320in which the shaft16(FIG.2) is received.

The first and second mating faces214,216are shown in greater detail inFIG.10(with one portion210,220being shown because the portions210,220are identical). The mating faces214,216are also shown in their mating alignment in a first configuration (FIG.11) and a second configuration (FIG.13) in which the first sprocket portion210is rotated 180° from the first configuration (FIG.11). The first mating face214includes a first protrusion132and a first recess142. Likewise, the second mating face216includes a second protrusion134and a second recess144. Each protrusion132,134includes an elevated surface162,164(FIG.10) that is elevated relative to the neutral plane170(FIG.9) of the mating face214,216. Each recess142,144includes a recessed surface166,168that is recessed relative to the neutral plane170(FIG.9) of the mating face214,216. Each recess142,144is disposed across the mid-plane180(FIG.9) and opposite from the protrusion132,134(i.e., across the mid-plane180and the same distance from the center plane190).

The first mating face214may also include a first landing152and the second mating face216may also include a second landing154. In the illustrated embodiment, the first landing152is a third recess146and the second landing154is a fourth recess148. The third and fourth recesses146,148each have a depth less than a depth of the first and second recesses142,144. In other embodiments, the first landing152is a flat surface (not shown) of the first mating face214and the second landing154is a flat surface (not shown) of the second mating face216(i.e., the recesses146,148are eliminated).

The first mating face214and second mating face216may include additional projections252,258and recesses262,266that are opposite each other across the mid-plane180(FIG.9). In some embodiments, these additional projections252,258and recesses262,266are eliminated (i.e., the split sprocket may have a single projection and a single recess on each mating face to function as described herein). Another embodiment of the split sprocket portion210,220is shown inFIG.16. The split sprocket portion210,22includes a further recess272(e.g., to aid in alignment).

The split sprocket20may be assembled in a first configuration410(FIGS.11-12C) in which the sprocket20is tightly secured to the shaft16in a fixed axial position along its length. In the first configuration410, the first protrusion132of the first sprocket portion210is received in the second recess144of the second sprocket portion220, and the second protrusion134of the second sprocket portion220is received in the first recess142of the first sprocket portion210. In the first configuration410, the first sprocket wheel segment244and the fourth sprocket wheel segment256mate to form a first sprocket wheel270and the second sprocket wheel segment246and the third sprocket wheel segment254mate to form a second sprocket wheel280(the wheels270,280being shown inFIG.5but one of the sprocket portions210,220is rotated 180° from the position inFIG.5in this first configuration).

By rotating one of the sprocket portions210,220180° from the position shown inFIGS.11-12c, the split sprocket20may be selectively assembled in a second configuration420(FIGS.3-5and13-14C). In the second configuration420, the sprocket20is loosely coupled to the shaft16and able to slide along its length. In the second configuration420, the first protrusion132of the first sprocket portion210contacts the second landing154of the second sprocket portion220and the second protrusion134of the second sprocket portion220contacts the first landing152of the first sprocket portion210. In the second configuration420, the first sprocket wheel segment244and the third sprocket wheel segment254mate to form a first sprocket wheel270(FIG.5), and the second sprocket wheel segment246and the fourth sprocket wheel segment256mate to form a second sprocket wheel280.

In both configurations410,420, the first and second hub segments340,350form a center hub360(FIG.5) disposed between the first and second sprocket wheels270,280. The clamp32contacts the center hub360to secure the first sprocket portion210to the second sprocket portion220.

When assembled in the first configuration410(FIGS.11-12C), the first sprocket portion notch310and the second sprocket portion notch320form a first sprocket opening370(FIG.12A) for receiving the shaft16. The sprocket portions210,220engage tightly with the shaft16to secure the sprocket20to the shaft16in a fixed axial position. The clearance C410(FIG.12B) between the shaft16(i.e., along the sides314,316of the shaft16that are parallel to the split between the first and second portions210,220) and the first and second sprocket portions210,220is zero such that the first and second portions210,220contact the shaft16at its sides314,316.

When assembled in the second configuration420, the first sprocket portion notch310and the second sprocket portion notch320form a second sprocket opening380for receiving the shaft16. As shown inFIG.14B, the sprocket portions210,220maintain a clearance fit C420with the shaft16to allow the sprocket20to slide along the length of the shaft (i.e., the first and second sprocket portions210,220do not contact the shaft sides314,316). Accordingly, the width W420(FIG.14A) of the second sprocket opening380exceeds the width W410of the first sprocket opening370.

The first sprocket portion notch310and the second sprocket portion notch320are sized to provide clearance between the first and second sprocket portions210,220and the sides318,322of the shaft16that are perpendicular to the split between the first and second sprocket portions210,220. This clearance fit with the shaft sides318,322allows the split sprocket20to float in the second configuration420(but be fixed in the first configuration410due to the contact fit between shaft sides314,316and the first and second portions210,220).

The first sprocket opening370and second sprocket opening380may have the same shape as the cross-section of the shaft16. For example, a square shaft16may be paired with embodiments having a square first sprocket opening370and second sprocket opening380. If the cross-section of the shaft16is circular, a key390(not shown) may secure the split sprocket20to the shaft16.

Another embodiment of the split sprocket having a different arrangement of the protrusions132,134and recesses142,144on the first and second sprocket portions210,220is shown inFIG.15. As shown inFIG.15, the recess142,144are disposed across the center plane190(FIG.9) (rather than the mid-plane180as in the embodiment illustrated inFIG.10) and opposite from the protrusion132,134. Depending on whether the first and second sprocket portions210,220are arranged in the first or second configuration, the projections132,134may contact the recess142,144or the landing152,154. The split sprocket ofFIG.15may be otherwise identical to the split sprocket20described above.

It should be noted that the split sprockets described above are exemplary and the projection and recesses of the sprocket portions may generally be arranged in any manner and position in which the sprocket portions may be selectively positioned in a first configuration in which the sprocket is fixed to the shaft and a second configuration having a clearance fit to allow the sprocket to move axially along the shaft. The sprocket portions may have additional projections or recesses that allow the split sprocket to function as described herein. In some embodiments, the second set of projections252,258and recesses262,266may be eliminated.

Compared to conventional sprockets, the sprockets of the present disclosure have several advantages. The split design of the sprocket enables its easy removal from the shaft without any further machine disassembly, allowing parts to be quickly removed, sanitized, and reinstalled. Additionally, the design employs two identical sprocket portions to form a full sprocket wheel, providing flexibility in substituting parts in and out of service. The two identical portions can be assembled in two a first configuration in which the sprocket may float along the shaft to allow for thermal expansion of the belt and a second configuration in which the sprocket is axially fixed to the shaft to maintain belt alignment. The sprocket's fixed configuration allows it to bind tightly to the shaft without the use of additional clamps or collars that would need to slide off the end of the shaft for removal. Use of a split sprocket having two sprocket wheels allows a single clamp to secure the first and second sprocket portions together. Embodiments having a recessed landing promote alignment of the two sprocket portions and prevent binding in the floating configuration of the sprocket.