Patent Publication Number: US-9416688-B2

Title: Switchable finger follower with combined lost motion spring and hydraulic lash adjuster clip

Description:
INCORPORATION BY REFERENCE 
     The following documents are incorporated herein by reference as if fully set forth: U.S. Provisional Patent Application No. 61/937,318, filed Feb. 7, 2014. 
     FIELD OF INVENTION 
     This invention is generally related to a switchable roller finger follower and more particularly to a lost motion spring for a switchable roller finger follower. 
     BACKGROUND 
     Switchable roller finger followers with varying lift modes are known. Typically, such finger followers have an outer elongated body with one end that contacts a valve stem. An inner elongated body is located within a cavity of the outer elongated body and houses a cam follower that contacts a cam to provide motion to the finger follower to open or close a valve. One end of the outer elongated body or the inner elongated body contacts a hydraulic lash adjuster. A latching mechanism is used to lock the inner elongated body in a fixed position relative to the outer elongated body. When the inner elongated body is locked via the latching mechanism, the cam translates movement to the finger follower which in turn translates movement to the valve via the valve stem. In order to switch the finger follower to a different lift mode or to deactivate the finger follower, the latching mechanism is released and the inner elongated body is unlocked and can travel freely up and down in conjunction with the cam without transferring the cam motion to the outer body and valve stem. Known finger followers provide lost motion springs to maintain contact between the cam follower and the cam. 
     Hydraulic lash adjuster clips are also known and are used to retain a support element of a hydraulic lash adjuster to a switchable roller finger follower. Typically, a separately formed clip is required for retaining the hydraulic lash adjuster with the inner elongated body of the finger follower. This entails additional expense in the formation of the inner elongated body to receive the clip, as well as additional parts and costs due to the more complex assembly required. 
     SUMMARY 
     It would be desirable to provide a simplified assembly for a switchable roller finger follower, as well as reduced parts and cost. This is achieved by the invention in that a combined lost motion spring and retention element for retaining a hydraulic lash adjuster to the switchable roller finger follower is provided. 
     In a preferred arrangement, the switchable roller finger follower includes an outer elongated body having a valve stem end and a lash adjuster end. The outer elongated body includes two outer elongated body side walls that are connected by a pin. Each of the side walls includes a spring pallet. The outer elongated body includes an inner cavity located between the side walls. An inner elongated body is positioned in the inner cavity and has a first end pivotally attached to the outer elongated body at said valve stem end via the pin, and a second, lash adjuster end. The inner elongated body includes a socket portion defined at the second end on a bottom portion of the inner elongated body. The second end of the inner elongated body also includes a locking mechanism that is hydraulically actuable to extend two locking pins out from the inner elongated body to engage under the lash adjuster ends of the outer elongated body side walls, in the locked position, and can be moved inwardly so that the outer elongated body is pivotable relative to the inner elongated body about the pin in the unlocked position. Two spring holding pins are located on opposite sides of the inner elongated body at the second end. At least one spring having two coiled spring portions is provided, and each of the two coiled spring portions is wrapped around a respective one of the spring holding pins. Each one of the at least two coiled spring portions includes a first leg and a second leg. Each of the first legs extends from a respective one of the two coiled spring portions to engage a respective one of the spring pallets. Each of the second legs contacts the bottom portion of the inner elongated body in proximity to the socket portion to act as a retainer for retaining a hydraulic lash adjuster to the inner elongated body. 
     Preferred arrangements with one or more features of the invention are described below and in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing Summary as well as the following Detailed Description will be best understood when read in conjunction with the appended drawings. In the drawings: 
         FIG. 1  is a perspective view of a top portion of a switchable roller finger follower according to the present invention. 
         FIG. 2  is a perspective view of a bottom portion of the finger follower according to the invention. 
         FIG. 3  is a perspective view of a first embodiment of a spring for the finger follower of  FIGS. 1 and 2 . 
         FIG. 4  is a partial cross-sectional view of an inner elongated body of the finger follower with a hydraulic lash adjuster. 
         FIG. 5  is a perspective view of a finger follower according to a second embodiment of the present invention. 
         FIG. 6  is a perspective view of a bottom portion of the finger follower of  FIG. 5 . 
         FIG. 7  is perspective view of a finger follower according to a third embodiment of the present invention. 
         FIG. 8  is a perspective view of a bottom portion of the finger follower of  FIG. 7 . 
         FIG. 9  is a perspective view of the springs used in the third embodiment of the finger follower shown in  FIGS. 7 and 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Certain terminology is used in the following description for convenience only and is not limiting. The words “inner,” “outer,” “inwardly,” and “outwardly” refer to directions towards and away from the parts referenced in the drawings. A reference to a list of items that are cited as “at least one of a, b, or c” (where a, b, and c represent the items being listed) means any single one of the items a, b, c or combinations thereof. The terminology includes the words specifically noted above, derivates thereof, and words of similar import. 
     As shown in  FIG. 1 , a switchable roller finger follower  1  is provided. The switchable roller finger follower  1  includes a primary lever and a secondary lever. One of ordinary skill in the art will recognize that the primary lever includes an end for a lash adjuster and an opposite end for valve actuation. One of ordinary skill in the art will recognize that the secondary lever includes a lost-motion spring pallet. The secondary lever also includes a cam-support surface for engaging with a cam. 
     In one embodiment, the switchable roller finger follower  1  includes an outer elongated body  2  having a valve stem end  3  and a lash adjuster end  4 . The outer elongated body  2  is formed by two outer elongated body side walls  5 ,  6  that are connected by a pin  7 , and each of the side walls  5 ,  6  includes a spring pallet  8 ,  9 , preferably on a bottom portion. The outer elongated body  2  has an inner cavity  10  located between the outer elongated body side walls  5 ,  6 . 
     An inner elongated body  11  is positioned in the inner cavity  10  of the outer elongated body  2 . The inner elongated body  11  has a first end  12  pivotally attached to the outer elongated body  2  at the valve stem end  3  by the pin  7 . The inner elongated body  11  has a second, lash adjuster end  13 . As shown in  FIG. 2 , the inner elongated body  11  includes a socket portion  14  defined at the second end  13  on a bottom portion of the inner elongated body  11 . The inner elongated body  11  includes a locking mechanism  15  located at the second end  13  of the inner elongated body  11 . The locking mechanism  15  is of the type known in the art, and is hydraulically actuable to extend two locking pins  15 A,  15 B out from the inner elongated body  11  to engage under the lash adjuster ends  4  of the outer elongated body side walls  5 ,  6 , in the locked position, and can be moved inwardly so that the outer elongated body  2  is pivotable relative to the inner elongated body  11  about the pin  7  in the unlocked position. Two spring holding pins  16 ,  17  are also located on opposite sides of the inner elongated body  11  at the second end  13 . 
     The switchable roller finger follower  1  includes at least one spring  18  having two coiled spring portions  19 ,  20 . Each of the two coiled spring portions  19 ,  20  is wrapped around a respective one of the spring holding pins  16 ,  17 . Each one of the at least two coiled spring portions  19 ,  20  includes a first leg  21 ,  22  and a second leg  23 ,  24 . Each of the first legs  21 ,  22  extends from a respective one of the two coiled spring portions  19 ,  20  to engage in or under a respective one of the spring pallets  8 ,  9 . As shown in  FIG. 4 , each of the second legs  23 ,  24  contacts the bottom portion of the inner elongated body  11  in proximity to the socket portion  14  to act as a retainer for retaining a hydraulic lash adjuster  28  having a complementary retaining recess  29  with the inner elongated body  11 .  FIG. 3  shows a first preferred embodiment of the spring  18  in which the second legs  23 ,  24  of the two coiled spring portions  19 ,  20  are formed integrally with each other and define a common second leg  25 , so that only one spring is required. The common second leg  25  can engage a spring catch protrusion  26  formed on the inner elongated body  11 . This spring has the advantage that it is form-locked in position on the inner body  11  once installed. The first legs  21 ,  22  can extend across the inner cavity  10  of the outer elongated body  2  and engage a spring pallet  8 ,  9  located on an opposite side of the outer elongated body  2  from the one of the at least two coiled spring portions  19 ,  20  from which the first leg  21 ,  22  extends. 
     Referring now to  FIGS. 5 and 6 , a second embodiment of a switchable roller finger follower  1 ′ is shown. The second embodiment is the same as the first embodiment, except the finger follower  1 ′ includes two separate springs  118 A and  118 B. Each of the springs  118 A,  118 B, includes a coiled spring portion  119 A,  120 B, a first leg  121 A,  122 B, and a second leg  123 A,  124 B. In the embodiment shown in  FIGS. 5 and 6 , the second legs  123 A,  124 B both engage the bottom portion of the inner elongated body  11  and extend in opposite transverse directions on opposite sides of the socket portion  14 . In the embodiment shown in  FIGS. 5 and 6 , the spring catch protrusion  26  is formed on the second end  13  of the inner elongated body  11 . In this embodiment, one of the second legs  123 A engages a bottom portion of the spring catch protrusion  26 . In another embodiment (not shown), the spring catch protrusion  26  is formed on an inner surface of the inner elongated body  11 . One of ordinary skill in the art will recognize from the present disclosure that the spring catch protrusion  26  can be provided on various portions of the inner elongated body  11 . 
     Referring now to  FIGS. 7-9 , a third embodiment of a switchable roller finger follower  1 ″ is shown. In this embodiment, two separately formed springs  218 A,  218 B are provided, each including respectively a coiled portion  219 A,  220 B, a first leg  221 A,  222 B, and a second leg  223 A,  224 B. The finger follower  1 ″ is the same as the finger follower  1 ′ of the second embodiment, except the second legs  223 A,  224 B engage the bottom portion of the inner elongated body  11  and extend in opposite longitudinal directions on opposite sides of the socket portion  14 , as shown in  FIGS. 7 and 8 . 
     Although the embodiments described above include an inner elongated body including the socket portion and locking mechanism, one of ordinary skill in the art will recognize that the outer elongated body could include the socket portion and locking mechanism for a hydraulic lash adjuster. 
     Having thus described various embodiments of the present switchable roller finger follower in detail, it is to be appreciated and will be apparent to those skilled in the art that many changes, only a few of which are exemplified in the detailed description above, could be made in the finger follower without altering the inventive concepts and principles embodied therein. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein. 
     LOG TO REFERENCE NUMBERS 
       1 ,  1 ′,  1 ″ Switchable roller finger follower 
       2  Outer elongated body 
       3  Valve stem end 
       4  Lash adjuster end 
       5 ,  6  Side walls of outer elongated body 
       7  Pin 
       8 ,  9  Spring pallets 
       10  Inner cavity 
       11  Inner elongated body 
       12  First end of inner elongated body 
       13  Second end of inner elongated body 
       14  Socket portion 
       15  Locking mechanism 
       15 A,  15 B Locking pins 
       16 ,  17  Spring holding pins 
       18  Spring 
       118 A,  118 B Springs 
       218 A,  218 B Springs 
       19 ,  20  Coiled spring portions 
       119 A,  120 B Coiled spring portions 
       219 A,  220 B Coiled spring portions 
       21 ,  22  First legs 
       121 A,  122 B First legs 
       221 A,  222 B First legs 
       23 ,  24  Second legs 
       123 A,  124 B Second legs 
       223 A,  224 B Second legs 
       25  Common second leg 
       26  Spring catch protrusion 
       28  Hydraulic lash adjuster 
       29  Recess on hydraulic lash adjuster