WO2009038935A1

WO2009038935A1 - Coupling device

Info

Publication number: WO2009038935A1
Application number: PCT/US2008/074368
Authority: WO
Inventors: Richard D. Kraus
Original assignee: The Timken Company
Priority date: 2007-09-18
Filing date: 2008-08-27
Publication date: 2009-03-26
Also published as: EP2207947A1; KR20100100760A; JP2010539392A; CN101815847A; US20110000451A1

Abstract

A unitized valve train assembly includes a finger follower having a pocket and a peripheral surface adjacent the pocket, and a hydraulic lash adjuster having a body, and a plunger extending from the body and received within the pocket of the finger follower. The plunger defines a longitudinal axis. The assembly also includes a single-wire coupling device having a first arm configured to selectively engage the finger follower, and a second arm clamped to one of the body and the plunger. The second arm is spaced from the peripheral surface of the finger follower when the plunger is received within the pocket of the finger follower.

Description

COUPLING DEVICE

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Serial

No. 60/973,313 filed on September 18, 2007, the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to couplings, and more particularly to couplings for use in connecting valve train components of an engine.

BACKGROUND OF THE INVENTION

[0003] When creating an assembly of components, it is often desirable to create multiple sub-assemblies, or "unitize" multiple individual components, to simplify or facilitate the assembly process. A valve train of an engine includes many components, and depending on the number of cylinders in the engine, assembling all of the valve train components may require a significant amount of time and precision when handling and connecting the individual components.

SUMMARY OF THE INVENTION

[0004] Unitizing two or more valve train components in an engine can reduce the amount of time and precision required when handling and connecting the unitized components.

[0005] The present invention provides, in one aspect, a device adapted to couple a finger follower and a hydraulic lash adjuster for use in a valve train of an engine. The hydraulic lash adjuster includes a plunger defining a longitudinal axis. The finger follower includes a pocket for receiving the plunger. The device includes a resilient clip having a first arm configured to selectively engage the finger follower and a second arm configured to receive the plunger of the hydraulic lash adjuster. The second arm of the clip includes a semi-circular or a hook portion that is engageable with the plunger from a direction substantially transverse to the longitudinal axis of the plunger. [0006] The present invention provides, in another aspect, a device adapted to couple a finger follower and a hydraulic lash adjuster for use in a valve train of an engine. The hydraulic lash adjuster includes a plunger defining a longitudinal axis and a body that receives the plunger therein. The finger follower includes a pocket for receiving the plunger. The device includes a resilient clip having a first arm configured to selectively engage the finger follower and a second arm configured to receive the body of the hydraulic lash adjuster. The second arm of the clip includes a substantially circular or hoop portion that is engageable with the body of the hydraulic lash adjuster.

[0007] The present invention provides, in yet another aspect, a unitized valve train assembly including a finger follower having a pocket, a hydraulic lash adjuster having a plunger received within the pocket of the finger follower, and a device, such as the resilient clips described above, coupling the finger follower and the hydraulic lash adjuster.

[0008] The present invention provides, in a further aspect, a unitized valve train assembly includes a finger follower having a pocket and a peripheral surface adjacent the pocket, and a hydraulic lash adjuster having a body, and a plunger extending from the body and received within the pocket of the finger follower. The plunger defines a longitudinal axis. The assembly also includes a single-wire coupling device having a first arm configured to selectively engage the finger follower, and a second arm clamped to one of the body and the plunger. The second arm is spaced from the peripheral surface of the finger follower when the plunger is received within the pocket of the finger follower.

[0009] The present invention provides, in another aspect, a unitized valve train assembly including a finger follower having a pocket, a hydraulic lash adjuster including a plunger received within the pocket of the finger follower, the plunger defining a longitudinal axis, and a coupling device. The coupling device includes a first arm configured to selectively engage the finger follower, and a second arm including a substantially semicircular hook portion engageable with the plunger from a direction substantially transverse to the longitudinal axis of the plunger. The hook portion defines an inner diameter. The hook portion includes opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion.

[0010] The present invention provides, in yet another aspect, a single-wire resilient clip adapted to couple a finger follower and a hydraulic lash adjuster for use in a valve train of an engine. The hydraulic lash adjuster has a plunger defining a longitudinal axis, and the finger follower has a pocket for receiving the plunger. The resilient clip includes a first arm configured to selectively engage the finger follower, and a second arm having a substantially semi-circular hook portion engageable with the plunger from a direction substantially transverse to the longitudinal axis of the plunger. The hook portion defines an inner diameter. The hook portion includes opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion.

[0011] The present invention provides, in a further aspect, a method of coupling a finger follower and a hydraulic lash adjuster for use in a valve train of an engine. The finger follower has a pocket for receiving a plunger of the hydraulic lash adjuster. The method includes providing a clip having a hook portion defining an inner diameter. The hook portion includes opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion. The method also includes inserting the plunger into the hook portion from a direction substantially transverse to a longitudinal axis of the plunger, spreading the opposite ends of the hook portion from each other during insertion of the plunger into the hook portion, clamping the plunger with the hook portion to secure the clip to the hydraulic lash adjuster, and positioning the plunger within the pocket of the finger follower.

[0012] Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a side, partial cutaway view of a unitized valve train assembly, including a first construction of a coupling device of the present invention coupling a roller finger follower and a hydraulic lash adjuster, assembled onto an engine.

[0014] FIG. 2 is an opposite side view of the unitized valve train assembly of FIG. 1.

[0015] FIG. 3 is a side perspective view of the unitized valve train assembly of FIG.

1.

[0016] FIG. 4 is an end perspective view of a portion of the unitized valve train assembly of FIG. 1.

[0017] FIG. 5 is an end view of the unitized valve train assembly of FIG. 1. [0018] FIG. 6 is a bottom perspective view of a portion of the unitized valve train assembly of FIG. 1.

[0019] FIG. 7 is a side perspective view of the coupling device of the unitized valve train assembly of FIG. 1.

[0020] FIG. 8 is a side view of the coupling device of the unitized valve train assembly of FIG. 1.

[0021] FIG. 9 is an end perspective view of the coupling device of the unitized valve train assembly of FIG. 1.

[0022] FIG. 10 is a side, partial cutaway view of a unitized valve train assembly, including a second construction of a coupling device of the present invention coupling a roller finger follower and a hydraulic lash adjuster, assembled onto an engine.

[0023] FIG. 11 is an opposite side view of the unitized valve train assembly of FIG.

10.

[0024] FIG. 12 is a side perspective view of the unitized valve train assembly of FIG.

10.

[0025] FIG. 13 is a top perspective view of the unitized valve train assembly of FIG.

10.

[0026] FIG. 14 is an end view of a portion of the unitized valve train assembly of

FIG. 10.

[0027] FIG. 15 is a top perspective view of a portion of the unitized valve train assembly of FIG. 10.

[0028] FIG. 16 is a side perspective view of the unitized valve train assembly of FIG.

10.

[0029] FIG. 17 is a side perspective view of the coupling device of the unitized valve train assembly of FIG. 10. [0030] FIG. 18 is an end perspective view of the coupling device of the unitized valve train assembly of FIG. 10.

[0031] FIG. 19 is a front perspective view of a plunger of a hydraulic lash adjuster of the unitized valve train assembly of FIGS. 1 and 10.

[0032] FIG. 20 is a side view of the unitized valve train assembly of FIG. 1 prior to engine assembly.

[0033] FIG. 21 is an opposite side view of the unitized valve train assembly of FIG. 1

[0034] FIG. 22 is a side view of the unitized valve train assembly of FIG. 10 prior to engine assembly.

[0035] FIG. 23 is a top perspective view of the unitized valve train assembly of FIG.

10 prior to engine assembly.

[0036] Before any 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 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 limiting. 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. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

DETAILED DESCRIPTION

[0037] FIGS. 1-6 illustrate a unitized valve train assembly 10 including a rocker arm or a spherical-end pivoting, roller cam follower assembly or roller finger follower 14, a hydraulic lash adjuster ("HLA") 18, and a coupling device 22 for unitizing or coupling the follower 14 and the HLA 18. The follower 14 includes a ball socket having a pocket 24 in which the spherical-pivot component of the HLA, customarily the piston or plunger 26, is received. A similar follower 14 is shown in published PCT Patent Application No. WO 2008/002746, the entire content of which is incorporated herein by reference. The HLA 18 includes a housing or body 30 in which the plunger 26 is supported, and the plunger 26 includes a shank 34 and a spherical end portion 38 which engages the pocket 24 of the follower 14 (see FIG. 19). Such a unitized valve train assembly 10 may be used, for example, in an engine having an overhead camshaft configuration. FIGS. 1-3 illustrate a cam lobe 42 of an overhead camshaft actuating the follower 14 and a corresponding valve 46.

[0038] With reference to FIGS. 1-6, the body 30 of the HLA 18 includes a cap 50 crimped to the upper portion of the body 30, thereby forming an integrated part of the body 30. As is known in the art, the cap 50 axially secures the plunger 26 within the body 30 and limits the axial extent to which the plunger 26 can extend from the body 30. Also, as shown in FIG. 19, the plunger 26 of the HLA 18 is configured with an undercut 54, a portion of which is defined by the shank 34. Alternatively, the plunger 26 of the HLA 18 may be configured without an undercut. Such a plunger without an undercut is shown and described in published PCT Patent Application No. WO 2008/002746.

[0039] With reference to FIGS. 7-9, the coupling device 22 is comprised of a clip 58 made from a single piece of resilient material (e.g., steel wire) that is bent or otherwise formed into the illustrated shape. In some constructions of the clip 58, the steel wire utilized to form the clip 58 has a diameter between about 0.5 and about 0.75 mm. Alternatively, other wire diameters may be utilized depending on the sizing of the other valve train components. The wire diameter utilized to form the clip 58 also affects the positional tolerance where the clip 58 may be attached to the plunger shank 34. The clip 58 should be secured to the plunger shank 34 in an axial position on the plunger shank 34 in which no portion of the clip 58 substantially interferes with movement of the plunger 26 or the follower 14 during operation of the engine. As such, decreasing the wire diameter of the clip 58 proportionally increases the positional tolerance where the clip 58 may be attached to the plunger shank 34.

[0040] The clip 58 includes a first or upper arm 62 selectively engageable with the follower 14, a second or lower arm 66 configured to engage and clamp onto the plunger 26, and an intermediate portion 70 interconnecting the upper and lower arms 62, 66. The upper arm 62 of the clip 58 is configured to extend around the ball socket of the follower 14 (see FIGS. 1 and 2). Specifically, the upper arm 62 includes an arcuate lip portion 74 engageable with the ball socket of the follower 14 to facilitate the connection of the clip 58 and the follower 14, and to provide resistance to the disconnection of the clip 58 and the follower 14.

[0041] In the illustrated construction of the clip 58 in FIG. 7, the lower arm 66 of the clip 58 includes a semi-circular portion or a hook portion 78 having opposite ends 82a, 82b and a splayed end portion 86 disposed toward the distal end of the hook portion 78. The hook portion 78 of the clip 58 includes an inner diameter Dl less than the outer diameter D2 of the plunger shank 34 (see FIG. 19), resulting in an interference fit between the clip 58 and the plunger shank 34 when the hook portion 78 of the clip 58 is engaged or clamped to the plunger shank 34. Such an interference fit substantially prevents the lower arm 66 of the clip 58 from rotating, pivoting, or rocking with respect to the plunger 26 during operation of the engine. In some constructions of the clip 58, the interference between the inner diameter Dl of the hook portion 78 and the outer diameter D2 of the plunger shank 34 may be between about 1% and about 8% of the outer diameter D2 of the plunger shank 34. In other words, the inner diameter Dl of the hook portion 78 may be between about 92% and about 99% of the outer diameter D2 of the plunger shank 34. Alternatively, in other constructions of the clip 58, the interference between the inner diameter Dl of the hook portion 78 and the outer diameter D2 of the plunger shank 34 may be about 4% of the outer diameter D2 of the plunger shank 34.

[0042] In addition, the respective ends 82a, 82b of the hook portion 78, when the clip

58 is removed from the plunger shank 34 and when the clip 58 is in its undeformed or undeflected state, may be spaced by a length or gap dimension D3 less than the outer diameter D2 of the plunger shank 34. In some constructions of the clip 58, the gap dimension D3 may be between about 5% and about 13% less than the outer diameter D2 of the plunger shank 34 when the clip 58 is removed from the plunger shank 34 and when the clip 58 is in its undeformed or undeflected state.

[0043] FIGS. 1-6 illustrate the clip 58 attached to the HLA 18. To preassemble the clip 58 and the HLA 18, the hook portion 78 is axially aligned with the plunger 26 and the clip 58 is moved toward the plunger 26 in a direction substantially transverse to a central axis 90 of the plunger 26 (see FIG. 19). After initial engagement of the splayed end portion 86 of the clip 58 and the end 82a of the hook portion 78, continued movement of the clip 58 in a direction substantially transverse to the central axis 90 of the plunger 26 causes the respective ends 82a, 82b of the hook portion 78 to separate as the plunger shank 34 is inserted between the ends 82a, 82b of the hook portion 78.

[0044] After the respective ends 82a, 82b of the hook portion 78 pass "over center" of the plunger shank 34 - i.e., immediately after the respective ends 82a, 82b of the hook portion 78 are spread such that the gap dimension D3 is substantially equal to the outer diameter D2 of the plunger shank 34 - the hook portion 78 snaps onto the plunger shank 34 to secure the clip 58 to the plunger 26. With reference to FIG. 6, after the clip 58 is engaged or clamped to the plunger shank 34, the gap dimension D3 between the respective ends 82a, 82b of the hook portion 78 is greater than the gap dimension D3 when the clip 58 is removed from the plunger shank 34. Specifically, in some constructions of the clip 58, the gap dimension D3 between the respective ends 82a, 82b of the hook portion 78 after the clip 58 is engaged to the plunger shank 34 is about 2% to about 5% less than the outer diameter D2 of the plunger shank 34. Because the hook portion 78 of the clip 58 cannot fully return to its undeformed or undeflected state shown in FIGS. 7 and 9 after it is engaged with the plunger shank 34, a clamping force is exerted on the plunger shank 34 by the hook portion 78 sufficient to generate frictional forces on the plunger shank 34 along and about the central axis 90 of the plunger 26 to substantially prevent the hook portion 78 from rotating, pivoting, or rocking with respect to the plunger shank 34 during operation of the engine.

[0045] However, the clip 58 may co-rotate with the plunger 26 with respect to the plunger body 30 and the follower 14. As shown in FIG. 5, the intermediate portion 70 of the clip 58 may come into contact with a side wall of the follower 14 should the plunger 26 and the clip 58 co-rotate about the central axis 90 during operation of the engine. As such, the side walls of the follower 14 limit the extent to which the plunger 26 and the clip 58 may co- rotate during operation of the engine.

[0046] After the clip 58 is secured to the HLA 18, the unitized clip 58 and HLA 18 may be assembled onto the follower 14 in substantially the same fashion as disclosed in published PCT Patent Application No. WO 2008/002746. The follower 14 may initially be oriented such that its pocket 24 may receive the spherical end portion 38 of the plunger 26. As the spherical end portion 38 of the plunger 26 is inserted into the pocket 24 of the follower 14, the arcuate lip portion 74 of the upper arm 62 may engage an upper surface of the follower 14, causing the clip 58 to deflect or elastically bend to an "open" position to complete the insertion of the spherical end portion 38 of the plunger 26 in the pocket 24 of the follower 14. After the pocket 24 of the follower 14 receives the spherical end portion 38 of the plunger 26, the clip 58 will resume its undeflected shape or its "closed" position to secure the follower 14 to the HLA 18, as shown in FIGS. 1-6.

[0047] Alternatively, the follower 14 and the HLA 18 may be pre-assembled by positioning the spherical end portion 38 of the plunger 26 into the pocket 24 of the follower 14, and the clip 58 may be brought in from the side of the pre-assembled follower 14 and HLA 18, in a direction substantially transverse to the central axis 90 of the plunger 26, to engage the hook portion 78 of the clip 58 and the plunger shank 34. Depending on the orientation of the follower 14, the upper arm 62 may or may not be deflected to clear the side wall of the follower 14 upon attachment of the clip 58 in this manner.

[0048] The follower 14 and HLA 18 can now be handled as a unit, without substantial concern that the HLA 18 may be unintentionally separated from the follower 14. To separate the HLA 18 and the follower 14, the arcuate lip portion 74 must be forced to pass over the upper surface of the follower 14, thereby causing the clip 58 to deflect back to its "open" position to allow removal of the spherical end portion 38 of the plunger 26 from the pocket 24. The resilient property of the clip 58 allows it to be bent slightly to permit insertion and removal of the follower 14 between the upper arm 62 of the clip 58 and the spherical end portion 38 of the plunger 26 without permanently distorting the clip 58 to the extent that its retention is substantially compromised.

[0049] When installed in an engine application, sufficient clearance is provided by the geometry of the clip 58 such that the follower 14 is able to pivot on the spherical end portion 38 of the plunger 26 through the necessary range of operating angles without causing damage to or binding of any components, including the follower 14 and the HLA 18 themselves, due to interference. Specifically, the arm 66 is positioned on the plunger shank 34 such that it is spaced, in a direction parallel to the longitudinal axis 90, from a bottom surface of the follower 14, and particularly a peripheral surface 92 adjacent the pocket 24, to prevent binding between the clip 58 and the follower 14. In addition, the arm 66 is positioned on the plunger shank 34 such that it is spaced, in a direction parallel to the longitudinal axis 90, from the cap 50 of the HLA 18 to prevent binding between the clip 58 and the HLA 18.

[0050] The clip 58 facilitates handling of the follower 14 and the HLA 18 as a unit, without substantial concern that the follower 14 and the HLA 18 may become unintentionally separated, without requiring any special features on either the follower 14 or the HLA 18, such as an undercut of the plunger shank 34, and without impeding the intended motion of either the follower 14 or the HLA 18, particularly the rotation of the plunger 26 in the body 30. FIGS. 20 and 21 illustrate the unitized valve train assembly 10 prior to engine installation. The clip 58 maintains the spherical end portion 38 of the plunger 26 at least partially within the pocket 24 of the follower 14 when only the follower 14 is grasped and picked up. In some constructions of the clip 58, the arcuate lip portion 74 may be spaced from the upper surface of the ball socket of the follower 14 by as much as about 2 mm to about 3 mm to allow sufficient play between the HLA 18 and the follower 14 yet prevent the HLA 18 from unintentionally disengaging and separating from the follower 14. Alternatively, depending on the sizing of the other valve train components, more or less spacing between the arcuate lip portion 74 and the upper surface of the follower ball socket may be utilized.

[0051] Once installed in a fully assembled engine, the clip 58 is no longer needed to keep the follower 14 assembled to the HLA 18. Rather, the clip 58 is only needed to keep the follower 14 from unintentionally separating from the HLA 18 when the engine is only partially assembled. Therefore, during operation of the fully assembled engine, little or no contact between the upper surface of the follower ball socket and the underside of the upper arm 62 or the arcuate lip portion 74 occurs because repeated contact may lead to wear or breakage of the clip 58. Contact between the upper surface of the ball socket and the underside of the upper arm 62 or the arcuate lip portion 74 usually only occurs during assembly, either when the follower 14 is installed onto the HLA 18, or when the follower 14 is being prevented from unintentionally separating from the HLA 18 during handling of the unitized valve train assembly 10.

[0052] FIGS. 10-16 illustrate a unitized valve train assembly 94 including another construction of the coupling device 98. Like components are labeled with like reference numerals. Generally, rather than being secured to the plunger 26 of the HLA 18, the coupling device 98 is secured to the body 30 of the HLA 18.

[0053] With reference to FIGS. 17 and 18, the coupling device 98 comprises a clip

102 made from a single piece of resilient material (e.g., steel wire) that is bent or otherwise formed in symmetrical halves about a plane containing the central axis 90 of the HLA 18. In some constructions of the clip 102, the steel wire utilized to form the clip 102 has a diameter between about 0.5 mm and about 0.75 mm. Alternatively, other wire diameters may be utilized depending on the sizing of the other valve train components, and the spacing between the body 30 of the HLA 18 and the follower 14.

[0054] The clip 102 includes a first or upper portion 106 selectively engageable with the follower 14, a second or lower portion 110 configured to engage the body 30 of the HLA 18, and an intermediate portion 114 interconnecting the upper and lower portions 106, 110. The upper portion 106 and the intermediate portion 114 of the clip 102 each include dual parallel segments 118 of the wire that extend from the hoop portion 126. Each wire segment 118 comprising the upper portion 106 also includes a splayed distal end 122 selectively engageable with the ball socket of the follower 14 to facilitate the connection of the clip 102 and the follower 14, and to provide resistance to the disconnection of the clip 102 and the follower 14.

[0055] In the illustrated construction of the clip 102 in FIG. 17, the lower portion 110 of the clip 102 includes a circular portion or a hoop portion 126 having an inner diameter D4 less than the outer diameter D5 of the cap 50 of the HLA 18 (see FIG. 14), resulting in an interference fit between the clip 102 and the body 30 when the hoop portion 126 of the clip 102 is engaged to the body 30. Such an interference fit substantially prevents the lower portion 110 of the clip 102 from rotating, pivoting, or rocking with respect to the body 30 during operation of the engine. In some constructions of the clip 102, in its undeformed or undeflected state, the hoop portion 126 of the clip 102 may have a diameter D4 between about 5% and about 10% less than the effective diameter D5 of the cap 50 to yield the interference fit between the clip 102 and the body 30. Alternatively, the clip 102 may be configured with only a single wire segment comprising the intermediate portion 114 of the clip 102, and only a single wire segment comprising the upper portion 106 of the clip 102.

[0056] FIGS. 10-16 illustrate the clip 102 attached or clamped to the HLA 18. To preassemble the clip 102 and the HLA 18, the hoop portion 126 of the clip 102 is aligned with the central axis 90 of the plunger 26, the plunger 26 is inserted through the hoop portion 126, and the individual wire segments 118 comprising the upper and intermediate portions 106, 114 of the clip 102 are spread apart to receive the body 30 of the HLA 18. Specifically, the wire segments 118 are spread apart to allow the hoop portion 126 to move over the cap 50, after which the wire segments 118 may be released to allow the clip 102 to clamp onto the cap 50 or another portion of the body 30. [0057] Because the hoop portion 126 of the clip 102 cannot fully return to its undeformed or undeflected state shown in FIGS. 17 and 18 after it is engaged with the body 30, a clamping force is exerted on the body 30 by the hoop portion 126 of the clip 102 sufficient to generate frictional forces on the body 30 along and about the central axis 90 of the plunger 26 to substantially prevent the hoop portion 126 of the clip 102 from rotating, pivoting, or rocking with respect to the body 30 during operation of the engine.

[0058] Assembly of the unitized clip 102 and HLA 18 may occur in substantially the same fashion as described above and as disclosed in published PCT Patent Application No. WO 2008/002746. FIGS. 22 and 23 illustrate the unitized valve train assembly 94 prior to engine installation. The discussion above relating to the unitized valve train assembly 10 in FIGS. 20 and 21 also applies to the unitized valve train assembly 94 in FIGS. 22 and 23. Like the clip 58 discussed above, the arm 110 is positioned on the cap 50 such that it is spaced, in a direction parallel to the longitudinal axis 90, from the bottom surface of the follower 14, and particularly the peripheral surface 92 adjacent the pocket 24, to prevent binding between the clip 102 and the follower 14.

[0059] Various features of the invention are set forth in the following claims.

Claims

CLAIMS What is claimed is:

1. A unitized valve train assembly comprising: a finger follower including a pocket and a peripheral surface adjacent the pocket; a hydraulic lash adjuster including a body; and a plunger extending from the body and received within the pocket of the finger follower, the plunger defining a longitudinal axis; a single-wire coupling device including a first arm configured to selectively engage the finger follower; and a second arm clamped to one of the body and the plunger; wherein the second arm is spaced from the peripheral surface of the finger follower when the plunger is received within the pocket of the finger follower.

2. The unitized valve train assembly of claim 1, wherein the second arm includes a substantially semi-circular hook portion clamped to the one of the body and the plunger from a direction substantially transverse to the longitudinal axis of the plunger.

3. The unitized valve train assembly of claim 2, wherein the hook portion defines an inner diameter, and wherein the hook portion includes opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion.

4. The unitized valve train assembly of claim 3, wherein the plunger defines an outer diameter greater than the inner diameter of the hook portion prior to clamping the hook portion to the plunger.

5. The unitized valve train assembly of claim 4, wherein a difference between the inner diameter of the hook portion and the outer diameter of the plunger yields an interference between about 1% and about 8% of the outer diameter of the plunger.

6. The unitized valve train assembly of claim 3, wherein the plunger defines an outer diameter greater than the gap between the respective ends of the hook portion prior to clamping the hook portion to the plunger, and wherein the respective ends of the hook portion spread apart from each other during clamping of the hook portion to the plunger.

7. The unitized valve train assembly of claim 6, wherein the gap between the respective ends of the hook portion prior to clamping the hook portion to the plunger is between about 5% and about 13% less than the outer diameter of the plunger.

8. The unitized valve train assembly of claim 2, wherein the hook portion is clamped to the plunger, and wherein the hook portion is spaced from the body when the plunger is received within the pocket of the finger follower.

9. The unitized valve train assembly of claim 2, wherein the plunger includes a shank and a spherical end portion, and wherein the hook portion is clamped to the shank.

10. The unitized valve train assembly of claim 9, wherein the first arm includes an arcuate lip portion configured to selectively engage the finger follower.

11. The unitized valve train assembly of claim 9, wherein at least a portion of the shank is cylindrical, and wherein substantially the entire length of the hook portion is engageable with the cylindrical portion of the shank.

12. The unitized valve train assembly of claim 1, wherein the coupling device is formed from a single wire having a circular cross-sectional shape.

13. The unitized valve train assembly of claim 12, wherein the single wire has a diameter between about 0.5 mm and about 0.75 mm.

14. The unitized valve train assembly of claim 1, wherein the second arm includes a hoop portion clamped to the body.

15. The unitized valve train assembly of claim 14, wherein the first arm includes dual, parallel wire segments, and wherein the coupling device further includes dual, parallel intermediate wire segments interconnecting the hoop portion and the respective wire segments of the first arm.

16. A unitized valve train assembly comprising: a finger follower including a pocket; a hydraulic lash adjuster including a plunger received within the pocket of the finger follower, the plunger defining a longitudinal axis; a coupling device including a first arm configured to selectively engage the finger follower; and a second arm including a substantially semi-circular hook portion engageable with the plunger from a direction substantially transverse to the longitudinal axis of the plunger; wherein the hook portion defines an inner diameter, and wherein the hook portion includes opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion.

17. The unitized valve train assembly of claim 16, wherein the plunger defines an outer diameter greater than the gap between the respective ends of the hook portion prior to assembly of the hydraulic lash adjuster and the coupling device, and wherein the respective ends of the hook portion spread apart from each other during assembly of the hydraulic lash adjuster and the coupling device.

18. The unitized valve train assembly of claim 17, wherein the gap between the respective ends of the hook portion prior to assembly of the hydraulic lash adjuster and the coupling device is between about 5% and about 13% less than the outer diameter of the plunger.

19. A single-wire resilient clip adapted to couple a finger follower and a hydraulic lash adjuster for use in a valve train of an engine, the hydraulic lash adjuster having a plunger defining a longitudinal axis, the finger follower having a pocket for receiving the plunger, the resilient clip comprising: a first arm configured to selectively engage the finger follower; and a second arm including a substantially semi-circular hook portion engageable with the plunger from a direction substantially transverse to the longitudinal axis of the plunger; wherein the hook portion defines an inner diameter, and wherein the hook portion includes opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion.

20. The single- wire resilient clip of claim 19, wherein the first arm includes an arcuate lip portion configured to selectively engage the finger follower.

21. The single- wire resilient clip of claim 19, further comprising an intermediate portion interconnecting the first and second arms, wherein the intermediate portion is oriented substantially normal to the first arm and the second arm.

22. A method of coupling a finger follower and a hydraulic lash adjuster for use in a valve train of an engine, the finger follower having a pocket for receiving a plunger of the hydraulic lash adjuster, the method comprising: providing a clip having a hook portion defining an inner diameter, the hook portion including opposite ends defining therebetween a minimum gap less than the inner diameter of the hook portion; inserting the plunger into the hook portion in a direction substantially transverse to a longitudinal axis of the plunger; spreading the opposite ends of the hook portion from each other during insertion of the plunger into the hook portion; clamping the plunger with the hook portion to secure the clip to the hydraulic lash adjuster; and positioning the plunger within the pocket of the finger follower.

23. The method of claim 22, further comprising: providing a first arm on the clip having the hook portion; providing a second arm on the clip spaced from the first arm; and supporting the hydraulic lash adjuster from the finger follower via engagement of the first arm and the finger follower.