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Title:
CLUTCH ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2018/017512
Kind Code:
A1
Abstract:
A clutch assembly for selectively connecting a drive shaft of an agricultural implement to a gearbox of an individual row unit on the implement. The clutch assembly may include an inner member for connection to the drive shaft, an outer member selectively powered by the inner member via clutch components, and a coupler connecting the outer member to the gearbox. The coupler may be adapted to connect to the outer member in a manner allowing axial and/or radial misalignment between the outer member and the gear box.

Inventors:
SPERFSLAGE DANIEL EUGENE (US)
ZANGL SCOTT JASON (US)
JAEGER DARYL JAMES (US)
Application Number:
PCT/US2017/042482
Publication Date:
January 25, 2018
Filing Date:
July 18, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ACTUANT CORP (US)
International Classes:
F16D43/202; F16D7/04
Foreign References:
EP2436944A22012-04-04
EP2221495A12010-08-25
EP2136095A12009-12-23
US20050103592A12005-05-19
JP2014035074A2014-02-24
US7794329B22010-09-14
US6447397B12002-09-10
Attorney, Agent or Firm:
LAWSON, Edward, R. et al. (US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A clutch assembly for selectively connecting a drive shaft of an agricultural implement to a gearbox, the clutch assembly comprising:

an outer member defining a recess;

an inner member radially inward of the outer member and adapted to be received on the drive shaft, the inner member defining an opening;

at least one detent between the inner member and the outer member operable to maintain the inner member and the outer member in rotational driving engagement below a torque threshold, each detent including a driving member operable to slide radially in the opening in the inner member between an engaged position, in which the driving member is seated in the recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is disengaged from the recess and the outer member is rotatable relative to the inner member;

a spring operable to exert an axial spring force biasing the driving member radially outwardly toward the engaged position;

a seal extending between the inner member and the outer member, the seal having a portion received within the recess of the outer member; and

a coupler adapted to drivingly connect the outer member to the gearbox of the implement, the coupler including at least one projecting lobe engaged in the recess of the outer member.

2. The clutch assembly of claim 1, wherein the driving member has a surface engageable with the outer member, the surface being interrupted.

3. The clutch assembly of claim 2, wherein the surface has a plurality of impressions.

4. The clutch assembly of claim 1, wherein the driving member has a surface engageable with the inner member, the surface being interrupted.

5. The clutch assembly of claim 4, wherein the surface has a plurality of impressions.

6. The clutch assembly of claim 5, wherein the driving member has a second surface engageable with the outer member, the second surface having a plurality of impressions.

7. The clutch assembly of claim 1, wherein the at least one detent includes three detents, the outer member defining three recesses, the detents including three driving members, each driving member being selectively engageable in one recess.

8. The clutch assembly of claim 7, further comprising a ring between the driving members and the spring, the ring having a ramped surface on one axial end, wherein, above a torque threshold, the driving members move radially inwardly and disengage from the recesses, and wherein radially inward movement of the driving members causes axial movement of the ring against the spring.

9. The clutch assembly of claim 1, wherein the driving member has a ramped surface operable, above the torque threshold, to cause the driving member to move radially inwardly and disengage the recess.

10. The clutch assembly of claim 1, wherein the outer member defines three recesses, and wherein the coupler includes three projecting lobes, each lobe being engageable in a recess.

11. The clutch assembly of claim 1, wherein the projecting lobe is constructed to allow the coupler to tilt relative to the outer member.

12. The clutch assembly of claim 1, wherein coupler has the projecting lobe at one end and a flanged connection on an opposite end and adapted to receive a shaft from the gearbox, the flanged connection having a threaded aperture for receiving a threaded fastener to connect the coupler to the shaft.

13. The clutch assembly of claim 1, wherein the outer member defines three recesses, and wherein the seal includes three lobes, each lobe being received within one recess.

14. The clutch assembly of claim 1, wherein the seal further includes a circumferentially- extending lip engageable with the outer member.

15. The clutch assembly of claim 14, wherein the seal further includes a second lip engageable with the inner member.

16. The clutch assembly of claim 15, wherein the seal further includes a circumferential rib extending from the seal in an axial direction engageable with a mating circumferential recess on the inner housing.

17. A torque overload clutch assembly comprising:

an outer member defining a recess;

an inner member radially inward of the outer member and defining an opening; and a detent between the inner member and the outer member operable to maintain the inner member and the outer member in rotational driving engagement below a torque threshold, the detent including a driving member operable to slide radially in the opening in the inner member between an engaged position, in which the driving member is seated in the recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is disengaged from the recess and the outer member is rotatable relative to the inner member, the driving member having a first surface engageable with the inner member and a second surface engageable with the outer member, at least one of the first surface and the second surface being interrupted.

18. The clutch assembly of claim 17, wherein each of the first surface and the second surface is interrupted.

19. The clutch assembly of claim 18, wherein each of the first surface and the second surface include a plurality of impressions.

20. The clutch assembly of claim 17, wherein the at least one of the first surface and the second surface includes a plurality of impressions.

21. The clutch assembly of claim 17, wherein the outer member defines three recesses, wherein the inner member defines three openings, and wherein the clutch assembly further comprises three detents between the inner member and the outer member operable to maintain the inner member and the outer member in rotational driving engagement below the torque threshold, each detent including a driving member operable to slide radially in one opening in the inner member between an engaged position, in which the driving member is seated in one recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is disengaged from the recesses and the outer member is rotatable relative to the inner member, each driving member having a first surface engageable with the inner member and a second surface engageable with the outer member, at least one of the first surface and the second surface being interrupted

22. The clutch assembly of claim 17, further comprising a seal extending between the inner member and the outer member, the seal having a portion received within the recess of the outer member.

23. The clutch assembly of claim 22, wherein the outer member defines three recesses, and wherein the seal includes three lobes, each lobe being received within one recess.

24. The clutch assembly of claim 22, wherein the seal further includes a

circumferentially-extending lip engageable with the outer member.

25. The clutch assembly of claim 24, wherein the seal further includes a second lip engageable with the inner member.

26. The clutch assembly of claim 25, wherein the seal further includes a circumferential rib extending from the seal in an axial direction engageable with a mating circumferential recess on the inner housing.

27. The clutch assembly of claim 17, further comprising a spring operable to exert an axial spring force biasing the driving member radially outwardly toward the engaged position.

28. The clutch assembly of claim 27, wherein the at least one detent includes three detents, the outer member defining three recesses, the detents including three driving members, each driving member being selectively engageable in one recess.

29. The clutch assembly of claim 28, further comprising a ring between the driving members and the spring, the ring having a ramped surface on one axial end, wherein, above a torque threshold, the driving members move radially inwardly and disengage from the recesses, and wherein radially inward movement of the driving members causes axial movement of the ring against the spring.

30. The clutch assembly of claim 17, wherein the driving member has a ramped surface operable, above the torque threshold, to cause the driving member to move radially inwardly and disengage the recess.

31. The clutch assembly of claim 17, wherein the clutch assembly is operable to selectively connect a drive shaft of an agricultural implement to a gearbox, and the clutch assembly comprises a coupler adapted to drivingly connect the outer member to the gearbox of the implement, the coupler including at least one projecting lobe engaged in the recess of the outer member.

32. The clutch assembly of claim 31 , wherein the outer member defines three recesses, and wherein the coupler includes three projecting lobes, each lobe being engageable in a recess.

33. The clutch assembly of claim 31 , wherein the projecting lobe is constructed to allow the coupler to tilt relative to the outer member.

34. The clutch assembly of claim 31 , wherein coupler has the projecting lobe at one end and a flanged connection on an opposite end and adapted to receive a shaft from the gearbox, the flanged connection having a threaded aperture for receiving a threaded fastener to connect the coupler to the shaft.

Description:
CLUTCH ASSEMBLY

RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 62/363,990, filed July 19, 2016, the entire contents of which is hereby incorporated by reference.

FIELD

[0002] This invention generally relates to a torque overload clutch assembly and, in particular, to a clutch assembly for a gearbox of a corn head row unit.

SUMMARY

[0003] Existing clutch assemblies can suffer from a variety of problems. For example, some clutch assemblies have fretting corrosion problems. Others have problems with lubrication, as seals may not be provided to maintain lubricant and seal out the environment. Furthermore, some clutch assemblies do not allow for axial and/or radial misalignment between a drive member and a driven member, such as can happen on a corn head row unit. Finally, many existing clutch assemblies are quite complex with respect to the total number of parts required to connect and disconnect the clutch assembly.

[0004] Thus, a need may exist for a clutch assembly that can address one or more of these and/or other problems.

[0005] One independent aspect of the present invention relates to a clutch assembly for selectively connecting a common drive shaft of an agricultural implement to a gearbox of an individual row unit on the implement. The clutch assembly may generally include an outer member; an inner member radially inward of the outer member and adapted to be received on the common drive shaft; at least one detent between the inner member and the outer member operable to maintain the members in rotational driving engagement with one another below a certain overload torque between the members, each detent including a driving member that slides radially in an opening in the inner member between an engaged position, in which the driving member is seated in a recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is retracted from the recess and the outer member is continuously rotatable relative to the inner member, the driving member being moved radially outwardly to engage in the recess by a spring that exerts an axial spring force that biases the driving member into the engaged position; a seal extending between the inner member and the outer member to protect the detent and the spring, the seal having a portion received within the recess of the outer member; and a coupler adapted to drivingly connect the outer member to the gearbox of an individual row unit, the coupler having at least one projecting lobe engaged in the recess of the outer member.

[0006] In some embodiments, the clutch may further include a plurality of impressions on the surface of the driving member (or other members engaging the driving member) to prevent fretting corrosion.

[0007] In some embodiments, the outer member may have at least three recesses for engaging at least three detents and at least three projecting lobes on the coupler. The at least three projecting lobes may allow the coupler to tilt with respect to the outer member to allow for axial misalignment between the gearbox and common drive shaft. In some embodiments, coupler may also have the at least three projecting lobes on a first end of the coupler, the coupler having a flanged connection on the opposite end of the coupler adapted to receive a shaft from the gearbox, the flanged connection having a threaded aperture for receiving a threaded fastener to connect the coupler to the shaft.

[0008] In some embodiments, the seal may further include at least three lobes received within the at least three recesses of the outer member. The seal can also have a

circumferentially extending lip that engages the outer member, a second lip engaging the inner member, and/or a circumferential rib extending from the seal in an axial direction which engages a mating circumferential recess on the inner housing.

[0009] Another independent aspect of the present invention generally relates to a torque overload clutch to prevent fretting corrosion. The clutch may generally have an outer member; an inner member radially inward of the outer member; at least one detent between the inner member and the outer member operable to maintain the members in rotational driving engagement with one another below a certain overload torque between the members, each detent including a driving member that slides radially in an opening in the inner member between an engaged position, in which the driving member is seated in a recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is retracted from the recess and the outer member is continuously rotatable relative to the inner member, the driving member being moved radially outwardly to engage in the recess by a spring that exerts an axial spring force that biases the driving member into the engaged position; an actuator ring axially between the driving member and the spring, the spring biasing the actuator ring so as to cam the driving member on the actuator ring radially outwardly. A plurality of impressions may be provided on the surface of the driving member (or other members engaging the driving member) to prevent fretting corrosion.

[0010] In one independent embodiment, a clutch assembly for selectively connecting a drive shaft of an agricultural implement to a gearbox may be provided. The clutch assembly may generally include an outer member defining a recess; an inner member radially inward of the outer member and adapted to be received on the drive shaft, the inner member defining an opening; at least one detent between the inner member and the outer member operable to maintain the inner member and the outer member in rotational driving engagement below a torque threshold, each detent including a driving member operable to slide radially in the opening in the inner member between an engaged position, in which the driving member is seated in the recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is disengaged from the recess and the outer member is rotatable relative to the inner member; a spring operable to exert an axial spring force biasing the driving member radially outwardly toward the engaged position; a seal extending between the inner member and the outer member, the seal having a portion received within the recess of the outer member; and a coupler adapted to drivingly connect the outer member to the gearbox of the implement, the coupler including at least one projecting lobe engaged in the recess of the outer member.

[0011] In another independent embodiment, a torque overload clutch assembly may generally include an outer member defining a recess; an inner member radially inward of the outer member and defining an opening; and a detent between the inner member and the outer member operable to maintain the inner member and the outer member in rotational driving engagement below a torque threshold, the detent including a driving member operable to slide radially in the opening in the inner member between an engaged position, in which the driving member is seated in the recess of the outer member in driving engagement with the recess, and a disengaged position, in which the driving member is disengaged from the recess and the outer member is rotatable relative to the inner member, the driving member having a first surface engageable with the inner member and a second surface engageable with the outer member, at least one of the first surface and the second surface being interrupted.

[0012] Other independent aspects of the invention may become apparent by consideration of the detailed description, claim and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a perspective view of an overload clutch assembly connecting a main power shaft of an implement to a gearbox of a corn head row unit.

[0014] FIG. 2 is a perspective view of the clutch assembly of FIG. 1 with the housing being shown as translucent to illustrate components within the housing.

[0015] FIG. 3 is an exploded view of the coupler shown in FIG. 2 adjacent a driven shaft of the gearbox of FIG. 1.

[0016] FIG. 4 is a cross-sectional view of the clutch assembly of FIG. 2.

[0017] FIG. 5 is a perspective view of the clutch assembly of FIG. 4 with some internal components not illustrated to better illustrate the internal hub and pawls.

[0018] FIG. 6 is an end view of the clutch assembly as shown in FIG. 5.

[0019] FIG. 7 is a perspective view of the coupler shown in FIG. 2.

[0020] FIG. 8 is an end view of the coupler shown in FIG. 7.

[0021] FIG. 9 is a side view of the coupler shown in FIG. 2.

[0022] FIG. 10 is a partial cross-sectional view of the clutch assembly housing, inner hub, and seal.

[0023] FIG. 11 is a partial cross-sectional perspective view of the clutch assembly housing, inner hub, and seal of FIG. 10.

[0024] FIG.12 is a first end view of the seal of FIGS. 4 and 10-11.

[0025] FIG. 13 is an opposite end view of the seal of FIG. 12. [0026] FIG. 14 is a perspective view of a pawl embodying independent aspects of the present invention.

[0027] FIG. 15 is a side view of the pawl of FIG. 14. [0028] FIG. 16 is another side view of the pawl of FIG. 14. DETAILED DESCRIPTION

[0029] Before any independent embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other independent embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited.

[0030] The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "mounted," "connected," and "coupled" are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect.

[0031] Finally, as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify independent

embodiments of the invention. Accordingly, other altemative mechanical configurations are possible and fall within the spirit and scope of the present invention.

[0032] FIG. 1 illustrates one independent embodiment of a torque overload clutch assembly 10 coupled to main power shaft 12 of an implement, such as a com row unit. Referring to FIGS. 2-4, the clutch assembly 10 has an outer housing 14 and an inner hub 16. The inner hub 16 is rotatable relative to the housing 14 and has its inner end 18 contained within the housing 14. As best shown in FIG. 6, the inner hub 16 has an aperture with a mating shape to the main power shaft 12. [0033] A series of elements are positioned between the inner hub 16 and the housing 14 to selectively transmit rotational movement from the inner hub 16 to the housing 14. For example, typical clutch components can be utilized. In some embodiments, the clutch configuration of U. S. Patent No. 7,794,329, the entire contents of which is hereby incorporated by reference, can be utilized.

[0034] As best shown in FIGS. 2 and 4-6, detent arrangements are provided by each of three pawls 20 received in a corresponding radially extending slot 22 in the inner end 18 to transmit torque between the hub 16 and housing 14. The illustrated slots 22 are open at their rear ends.

[0035] Each pawl 20 is a driving member having a ramped surface 24 that cams on a mating ramped surface 26 of an actuator ring 28. The actuator ring 28 is biased axially toward the pawls 20 by a spring assembly including, in the illustrated construction, multiple disc springs 30 having a regressive spring rate as described in U. S. Patent No. 6,447,397, the entire contents of which is hereby incorporated by reference.

[0036] In some embodiments, such as is shown in FIGS. 14-16, the pawls 20 are provided with an interrupted surface having a plurality of impressions, such as dimples, other recesses or projections, series of cuts or grooves, etc. Such impressions may help prevent fretting corrosion, which can be common between a pawl and the hub 16. The impressions on the surface may help to maintain a lubricant between the pawl 20 and the hub 16, which prevents fretting corrosion. In some embodiments, all surfaces of the pawl 20 having contact with another metal surface of the clutch assembly 10 have such impressions. Alternatively, the surfaces of the clutch assembly 10 engaging the pawl 20 can be interrupted (e.g., provided with impressions).

[0037] A ring shaped thrust bearing 32 is positioned inside the housing 14, outside of the actuator ring 28 and between the outer ends of the pawls 20 and the axially inner side of a split retainer ring 34 snapped into an internal groove 36 in the housing 14. The thrust bearing 32 bears on the adjacent axially facing surface of end 18 on its left side, as viewed in FIG. 4, and on the ring 34 on its right side if the inner member 16 is attempted to be pulled out of the outer member 14. The retainer 34 captures the end 18 and the pawls 20 inside of the housing 14 and reacts against any excessive thrust loads the hub 16 exerts on the housing 14, that tend to pull the hub 16 axially out of the housing 14. [0038] The inner radius edges of the springs 30 react against the actuator ring 28, and the outer radius edges of the springs 30 react against a compression plate 38 or keeper held axially on the hub 16 by a split retainer ring 40 snapped into an external groove 42 in the hub 16. An O-ring 43 also seals the inner circumference of the compression plate 38 against the outer circumference of the hub 16, and an O-ring 44 seals the outer circumference of the compression plate 38 against the bore 46 in the end of the housing 14.

[0039] Referring to FIGS. 4 and 6, the pawls 20 are illustrated in their most radially outward, fully engaged positions. In this position, each pawl 20 has a steeply ramped outer corner engaged with a mating steeply ramped surface 50 formed in the interior surface of the housing 14. If a torque is exerted on the hub 16, the torque is exerted from the hub 16, through the pawls 20 bearing on the surfaces 50 to the housing 14.

[0040] If the torque capacity of the clutch assembly 10 is exceeded, the pawls 20 cam on the surfaces 50 and are pushed radially inwardly. In doing so, the pawls 20 cam on the ramped surface 26 of the ring 28, which urges the ring 28 axially away from the pawls 20 against the bias of the disc springs 30, permitting relative rotation of the hub 16 and housing 14 when the pawls 20 disengage from the surfaces 50.

[0041] Each time a pawl 20 passes a surface 50 as the hub 16 and housing 14 relatively rotate, it attempts to re-engage, producing a chattering noise. When the torque subsides to below the torque capacity of the clutch assembly 10, the re-engagement attempts are successful, arresting relative rotation between the hub 16 and the housing 14, to once again transmit torque from the hub 16 to the housing 14.

[0042] As shown in FIGS. 1-4, the clutch assembly 10 drives a coupler 52 which is utilized, in a preferred embodiment, to drive the gearbox 54 of a corn head row unit. As best shown in FIG. 3, the coupler 52 engages a driven shaft 56 of the gearbox 54. Rotation of the coupler 52 causes rotation of the driven shaft 56 and transmits power to the gearbox 54.

[0043] The coupler 52 is best shown in FIGS. 2, 4, and 7-9. The illustrated coupler 52 is particularly adapted to work with the illustrated housing 14. As noted above, the housing 14 has three slots 22 for receiving and housing the pawls 20. The coupler 52 has three lobes 58 sized and configured to be received within the slots 22 adjacent the inner end 18 of the inner hub 16. [0044] These lobes 58 are particularly useful for an application with a corn head row unit. On a single implement, radial and angular misalignment can occur due to a continuous shaft 12 running through multiple clutch assemblies 10 associated with multiple individually mounted gearboxes 54 (associated with each corn head row unit). The lobes 58 within the slots 22 allow for some angular and/or radial misalignment while still providing a driving engagement between the housing 14 and the gearbox 54. In other words, the coupler 52 can tilt or pivot via the engagement between the three lobes 58 and the three slots 22 to allow for such misalignment. As best shown in FIG. 9, the lobes 58 have an arced portion 60 (or are provided with a curved profile) in the axial direction to allow for such tilting, pivoting, and/or misalignment.

[0045] As assembled, the lobed end of the coupler 52 is located within a portion of the housing 14 that is axially longer than the lobed end of the coupler 52 to allow for the tilting and pivoting (best shown in FIG. 4). As further illustrated in FIGS. 2 and 4, the lobed end of the coupler 52 is retained within the housing 14 by a split retainer ring 64 received within an internal groove 66 in the housing 14. In some embodiments, the coupler 52 has an axial ridge 68 sized and configured to be received between the two ends of the split retainer ring 64. This ridge 68 prevents the split retainer ring 64 from rotating within the housing 14. Through the use of this retaining ring 64, the clutch assembly 10 can be removed from the coupler 52 via removal the retaining ring 64 only without the need to remove the coupler 52 from the gearbox 54.

[0046] As shown, the illustrated coupler 52 has a one piece design, which provides simplicity. The coupler 52 has a bore 62 extending therethrough in axial direction of the drive shaft 12. This bore 62 is sized and dimensioned to allow the drive shaft 12 to easily pass through without contact, even with some degree of misalignment between the housing 14 and the gearbox 54.

[0047] The opposite end of the coupler 52 has a bore sized and configured to receive the driven shaft 56 of the gearbox 54, as best shown in FIG. 3. This end has two flanges 70 adapted to receive two threaded fasteners 72. As best shown in FIG. 2, one of the flanged ends is provided with a bore sized to receive the threaded fastener 72. The other flanged end is tapped to threadingly receive the threaded fasteners 72. With this particular design, including the tapped holes, the coupler 52 can be connected to the gearbox fairly easily by simply manipulating the two threaded fasteners 72 - compared to other designs that may use both a nut and a bolt.

[0048] The two flanges 70 are separated by a cutout 74 which allows the flanged ends to deform and grip the driven shaft 56 upon fastening of the threaded fasteners 72. As shown in FIG. 3, the driven shaft 56 can also include slots 76 particularly adapted for receiving a portion of the threaded fasteners 72.

[0049] As best shown in FIGS. 4 and 10-13, the clutch assembly 10 also includes a seal 80 to protect the clutch components from environmental contamination. The seal 80 also functions to retain lubricant among the clutch components so as to not require separate grease fittings to provide lubrication.

[0050] As shown, the seal 80 is generally disc-shaped with a central aperture 82 and three radially projecting lobes 84 sized and configured to fit tightly within the slots 22 of the housing 14. The outer diameter of the seal 80 is sized and configured to form a friction fit or interference fit with the housing 14. As best shown in FIG. 10, the seal 80 is provided with a generally radially extending flexible lip 86 to snugly engage the housing 14 and allow tolerance variation while maintaining a sealed engagement with the housing 14.

[0051] The seal 80 further axially seals the clutch components from the environment via engagement with the end 18 of the inner hub 16. As illustrated, the seal 80 abuts the face of the end 18. Furthermore, the seal 80 includes an axially-extending projection 88

circumferentially about the aperture 82. The face of the end 18 is provided with a matingly shaped slot 90. Additionally, the seal 80 includes a radially extending flexible lip 92 that extends about the inner circumference of the seal 80 and engages the face of the end 18. This engagement of the lip 92 and the projection 88 of the seal 80 against the face of the end 18 forms a labyrinth design to inhibit or prevent ingress of environmental materials into the clutch components along the interface between the seal 80 and the end 18.

[0052] As shown in FIG. 4, the seal 80 is retained within the housing 14 by a split retainer ring 94 received within an internal groove 96 in the housing 14. The engagement between the split retainer ring 94 and the groove 96 is positioned to hold the seal 80 in engagement with the face of the end 18 of the inner hub 16. In some embodiments, the seal 80 is further provided with an axially-extending projection 98 to at least partially define a circumferential slot 100 housing the split retainer ring 94. [0053] The independent embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention. For example, the independent embodiment illustrated above is shown in connection with a com head row unit. In other independent embodiments, the clutch assembly can be used in other applications, particularly agricultural applications.

[0054] Various alternatives to the certain features and elements of the present invention are described with reference to specific independent embodiments of the present invention. With the exception of features, elements, and manners of operation that are mutually exclusive of or are inconsistent with each independent embodiment described above, it should be noted that the alternative features, elements, and manners of operation described with reference to one particular independent embodiment are applicable to the other independent embodiments.

[0055] One or more independent features and/or independent advantages may be set forth in the following claims: