Abstract:
An improved adjustment tab for a self-adjusting clutch, comprising a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage an adjustment means of the clutch; a first non-linear member emanating upwardly from the base member and arranged to clasp at least one of a plurality of lever arms; and, a second non-linear member emanating upwardly from the member and arranged to clasp at least one of the plurality of lever arms, and a clutch assembly which includes the improved adjustment tab.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/954,886, filed Mar. 18, 2014, which application is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates generally to clutch assemblies, and, more particularly, to an improved adjustment tab for an adjustment means within a clutch assembly. 
       BACKGROUND 
       [0003]    Clutch assemblies are used in motor vehicles between an engine and a transmission. A motor vehicle typically includes a single clutch or a dual clutch. In a motor vehicle with a single clutch, the clutch is coupled between the crankshaft and the input shaft of the transmission, thereby transferring torque from the crankshaft to the transmission. In a motor vehicle with a dual clutch, torque is transferred to two transmission input shafts arranged coaxially in relation to the other. Over time, the friction disc in the clutch assembly becomes increasingly worn. In order to compensate for the wear of the friction disc, the clutch assembly includes a means for adjusting the clutch assembly in relation to the amount of wear of the friction disc. The adjusting means includes at least one preloaded adjustment ring and a preloaded sensor ring with ramps provided between a clutch housing and lever arms. The adjustment and sensor rings are preloaded in a circumferential direction with pressure springs such that when the clutch disc becomes increasingly worn, the adjustment ring is forced to move in order to compensate the gap created between the pressure plate and the clutch disc. 
         [0004]    The adjusting means is activated by sensor devices, which measure either travel or an actuating force exerted by the lever arms. The sensor devices include a clamp spring and adjustment tabs. The clamp spring is fixedly secured to the housing of the clutch assembly and operatively arranged to engage the adjustment tabs. 
         [0005]    As described above, over time, the friction disc of the clutch assembly becomes worn; thus, the distance between the pressure plate and the friction disc increases. This increase in distance causes an increase in required engagement travel on the lever arms necessary to engage the pressure plate with the clutch disc. The adjustment tabs exert a predefined load on a sensor ring and sense the amount of wear or distance between the pressure plate and the friction disc. When the distance between the pressure plate and the friction disc increases, the lever arms engage the adjustment tab, then, the adjustment tab is lifted off, releasing the sensor ring. Since the adjustment tabs are also fixedly secured to the clamp spring, the axial movement of the lever arms causes the adjustment tabs and the clamp spring to undergo a travel or distance equal to the increase in distance between the pressure plate and the worn friction disc. 
         [0006]    To compensate for the increased travel or distance between the adjustment tabs and the sensor ring, and thus an increase in the distance necessary for the pressure plate to engage with the friction disc, the sensor ring moves axially to reengage with the adjustment tabs. As the sensor ring reengages with the adjustment tabs, the adjuster ring simultaneously moves axially a distance equal to the distance traveled by the sensor ring. The adjustment means (comprising the adjuster ring, the sensor ring, the clamp spring, the adjustment tabs and the lever arms) moves axially a distance equivalent to that traveled by the adjuster ring and the sensor ring, such that the distance between the pressure plate and the friction disc returns to its initial predetermined equilibrium position. 
         [0007]    A typical adjustment tab is disclosed in German Patent Application No. DE 102009053479 (Ruehle) filed Nov. 16, 2009. The clutch assembly disclosed includes an automatic readjusting device between the lever elements and the housing. The readjusting device described includes readjustment pieces which are secured to a sensor ring by rivets. However, due to the mass of the adjustment pieces and the structure of the assembly, unwanted rotation occurs. 
         [0008]    Another adjustment tab is disclosed in German Patent Application No. DE 102011102261 (Miguel) filed May 23, 2011. The friction clutch disclosed in this application includes a diaphragm spring for actuating a pressure plate and an adjustment means secured to a clamping spring by a screw. However, due to the mass of the adjustment means and the structure of the assembly, unwanted rotation occurs. 
         [0009]    The unwanted rotation described herein is demonstrated in  FIGS. 2A through 4  which show a typical clutch assembly having a typical adjustment tab. Typical clutch assembly  40  rotates about axis  41  and broadly includes outer housing  42 , central plate  43 , adjuster ring  44 , adjustment tabs  50 A,  50 B, and  50 C, clamp spring  51 , and sensor ring  54 . Rivets  49 B,  49 F, and  49 I secure clamp spring  51  and lever spring  57 A to outer housing  42 . Rivets  49 A,  49 C,  49 D,  49 E,  49 G, and  49 H secure lever spring  57 B to central plate  43 . Transport lock  58  is arranged proximate diaphragm spring  57 B. 
         [0010]    Typical adjustment tabs  50 A,  50 B,  50 C are secured to clamp spring  51  by screws  52 A,  52 B,  52 C, respectively, and bushings  53 A (shown in  FIG. 3C ),  53 B, and  53 C, respectively. Although bushings  53 B and  53 C are not shown, it should be understood that they are identical to bushing  53 A.  FIGS. 3A ,  3 B, and  3 C show typical adjustment tab  50 A, screw  52 A and bushing  53 A, respectively, which are required to secure typical adjustment tab  50 A to clamp spring  51 . Typical adjustment tab  50 A includes top portion  55 , feet  56 A and  56 B, and aperture  60 . The overall mass of adjustment tab  50 A is approximately 3.79 grams. Top portion  55  rests atop clamp spring  51  when typical adjustment tab  50 A is secured to clamp spring  51  and feet  56 A and  56 B surround clamp spring  51  (as shown in  FIG. 4 ). Aperture  60  is arranged to receive screw  52 A and bushing  53 A.  FIG. 3D  shows the bottom of typical adjustment tab  50 A. 
         [0011]    When typical adjustment tab  50 A and clamp spring  51  are secured together, clamp spring  51  exerts a downward force to the sensor ring  54 . As best shown in  FIG. 4 , top portion  55  of typical adjustment tab  50 A is positioned atop clamp spring  51 ; the same holds true for the other typical adjustment tabs  50 B and  50 C. Typical adjustment tab  50 A and clamp spring  51  have center of mass A, which is too high. Specifically, center of mass A is approximately 4.60 mm from the optimal center of mass along the abscissa shown in  FIG. 4  and approximately 1.90 mm from the optimal center of mass along the ordinate shown in  FIG. 4 . 
         [0012]    Unfortunately, while clutch assembly  40  rotates about axis  41 , due to the centrifugal force, each assembled typical adjustment tab  50 A,  50 B,  50 C and clamp spring  51  produce an unwanted outward rotation in the direction of the arrow shown in  FIG. 4 . Instead of maintaining a level position atop sensor ring  54 , the unwanted outward rotation causes each typical adjustment tab  50 A,  50 B,  50 C and clamp spring  51  to tilt outwardly and downwardly. The mass of each typical adjustment tab  50 A,  50 B,  50 C contributes to the unwanted rotation. 
         [0013]    Thus, there has been a long-felt need for an improved adjustment tab for a clutch assembly which, when assembled with a clamp spring of the clutch assembly, reduces the amount of unwanted outward rotation. 
       SUMMARY 
       [0014]    The invention is a clutch assembly for transferring a torque between a flywheel of an engine and a transmission in a motor vehicle, the clutch assembly comprising a housing, a pressure plate fixedly secured to the housing, the pressure plate operatively arranged to cause a friction clutch disc to engage the flywheel, wherein the pressure plate is arranged for rotation about an axis of rotation, wherein the pressure plate is axially movable relative to the axis of rotation, an adjustment means operatively arranged to adjust travel of the pressure plate and the friction clutch disc, and a plurality of lever arms operatively arranged to provide a force within the clutch assembly, the adjustment means further comprising: an adjustment tab comprising: a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage with the adjustment means of the clutch assembly; a first non-linear member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms; and, a second non-linear member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms. 
         [0015]    The invention also includes an improved adjustment tab for a self-adjusting clutch comprising a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage an adjustment means of the clutch; a first non-linear member emanating upwardly from the base member and arranged to clasp at least one of a plurality of lever arms; and, a second non-linear member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms. 
         [0016]    Furthermore, the invention includes a clutch assembly for transferring a torque between a flywheel of an engine and a transmission in a motor vehicle, the clutch assembly comprising a housing, a pressure plate fixedly secured to the housing, the pressure plate operatively arranged to cause a friction clutch disc to engage the flywheel, wherein the pressure plate is arranged for rotation about an axis of rotation, wherein the pressure plate is axially movable relative to the axis of rotation, an adjustment means operatively arranged to adjust travel of the pressure plate and the friction clutch disc, and a plurality of lever arms operatively arranged to provide a force within the clutch assembly, the adjustment means further comprising an adjustment tab/clamp spring assembly including an adjustment tab coupled to a clamp spring, wherein the clamp spring is operatively arranged to engage the adjustment means of the clutch assembly, and wherein the adjustment tab/clamp spring assembly has a center of mass which is co-planar with the clamp spring. 
         [0017]    Additionally, the invention includes an improved adjustment tab for a self-adjusting clutch comprising a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage an adjustment means of the clutch, a first member emanating upwardly from the base member and arranged to clasp at least one of a plurality of lever arms, and, a second member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms. 
         [0018]    A general object of the invention is to provide an improved adjustment tab for a clutch assembly which, when the improved adjustment tab is assembled with a clamp spring of the clutch assembly, results in a reduced amount of unwanted outward rotation. 
         [0019]    A further object of the invention is to provide an improved adjustment tab which can be integrally secured to a clamp spring of a clutch assembly. 
         [0020]    Another object of the invention is to provide an improved adjustment tab which has a reduced mass and, when the improved adjustment tab is coupled to a clamp spring of a clutch assembly, the improved adjustment tab and clamp spring exhibit an improved center of mass. 
         [0021]    These and other objects, features and advantages of the present invention will become readily apparent upon a review of the following detailed description of the invention, in view of the drawings and appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which: 
           [0023]      FIG. 1A  is a perspective view of a cylindrical coordinate system demonstrating spatial terminology used in the present application; 
           [0024]      FIG. 1B  is a perspective view of an object in the cylindrical coordinate system of  FIG. 1A  demonstrating spatial terminology used in the present application; 
           [0025]      FIG. 2A  is a perspective view of a clutch assembly having an adjustment tab; 
           [0026]      FIG. 2B  is a fragmentary view of the clutch assembly having the adjustment tab shown in  FIG. 2A ; 
           [0027]      FIG. 3A  is a perspective view of the prior art adjustment tab shown in  FIG. 2A ; 
           [0028]      FIG. 3B  is a perspective view of a screw of the prior art adjustment tab shown in  FIG. 2A ; 
           [0029]      FIG. 3C  is a perspective view of a bushing of the prior art adjustment tab shown in  FIG. 2A ; 
           [0030]      FIG. 3D  is a bottom plan view of the prior art adjustment tab shown in  FIG. 3A ; 
           [0031]      FIG. 4  is a fragmentary cross-sectional view of the clutch assembly shown in  FIG. 2B , taken generally along line  4 - 4  in  FIG. 2B ; 
           [0032]      FIG. 5  is a perspective view of a clutch assembly having the improved adjustment tab of the invention; 
           [0033]      FIG. 6  is a fragmentary view of the clutch assembly having the improved adjustment tab shown in  FIG. 5 ; 
           [0034]      FIG. 7A  is a perspective view of the improved adjustment tab shown in  FIG. 6 ; 
           [0035]      FIG. 7B  is a bottom plan view of the improved adjustment tab shown in  FIG. 7A ; 
           [0036]      FIG. 8  is a fragmentary cross-sectional view taken generally along line  8 - 8  in  FIG. 6 ; 
           [0037]      FIG. 9  is a perspective view of a second embodiment of an improved adjustment tab according to the invention; 
           [0038]      FIG. 10  is a perspective view of a third embodiment of an improved adjustment tab according to the invention; 
           [0039]      FIG. 11  is a fragmentary view of a clutch assembly having the improved adjustment tab shown in  FIG. 9 ; 
           [0040]      FIG. 12  is a fragmentary view of a clutch assembly having the improved adjustment tab shown in  FIG. 10 ; 
           [0041]      FIG. 13  is a fragmentary cross-sectional view of the clutch assembly shown in  FIG. 11 , taken generally along line  13 - 13  in  FIG. 11 ; and, 
           [0042]      FIG. 14  is a fragmentary cross-sectional view of the clutch assembly shown in  FIG. 12 , taken generally along line  14 - 14  in  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. It is to be understood that the invention as claimed is not limited to the disclosed aspects. 
         [0044]    Furthermore, it is understood that this patent is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention as claimed. 
         [0045]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention. 
         [0046]    The term “S”-shaped used herein refers to the general shape of non-linear members  113  and  114  and the term refers generally to the shape of a sigmoid curve. However, the term should not be so limited and non-linear members  113  and  114  can assume a variety of non-linear or linear shapes, for example, stepped shapes. 
         [0047]      FIG. 1A  is a perspective view of cylindrical coordinate system  10  demonstrating spatial terminology used in the present patent. The present invention is at least partially described within the context of cylindrical coordinate system  10 . System  10  has a longitudinal axis  1 , used as the reference for the directional and spatial terms that follow. Axial direction AD is parallel to axis  1 . Radial direction RD is orthogonal to axis  1 . Circumferential direction CD is defined by an endpoint of radius R (orthogonal to axis  1 ) rotated about axis  1 . 
         [0048]    To clarify the spatial terminology, objects  4 ,  5 , and  6  are used. Surface  7  of object  4  forms an axial plane. For example, axis  1  is congruent with surface  7 . Surface  8  of object  5  forms a radial plane. For example, radius  2  is congruent with surface  8 . Surface  9  of object  6  forms a circumferential surface. For example, circumference  3  is congruent with surface  9 . As a further example, axial movement or disposition is parallel to axis  1 ; radial movement or disposition is orthogonal to axis  2 , and circumferential movement or disposition is parallel to circumference  3 . Rotation is described herein with respect to axis  1 . 
         [0049]    The adverbs “axially,” “radially,” and “circumferentially” are used with respect to an orientation parallel to axis  1 , radius  2 , or circumference  3 , respectively. The adverbs “axially,” “radially,” and “circumferentially” are also used with respect to orientation parallel to respective planes. 
         [0050]      FIG. 1B  is a perspective view of object  15  in cylindrical coordinate system  10  of  FIG. 1A  demonstrating spatial terminology used in the present patent. Cylindrical object  15  is representative of a cylindrical object in a cylindrical coordinate system and is not intended to limit the claims of the present invention in any manner. Object  15  includes axial surface  11 , radial surface  12 , and circumferential surface  13 . Surface  11  is part of an axial plane; surface  12  is part of a radial plane, and surface  13  is part of a circumferential plane. 
         [0051]      FIGS. 5 through 8  show clutch assembly  100  including improved adjustment tabs  110 A,  110 B, and  110 C which are substantially similar. The description of improved adjustment tab  110 A applies to improved tabs  110 B and  110 C. Clutch assembly  100  is rotatable about axis  101 . Clutch assembly  100  broadly includes outer housing  102 , central plate  103 , sensor ring  104 , adjuster ring  105 , lever spring  107 A, lever spring  107 B, improved adjustment tabs  110 A,  110 B, and  110 C, and clamp spring  111 . Notably, adjustment tabs  110 A,  110 B, and  110 C engage clamp spring  111  without any screws and bushings or rivets. Clamp spring  111  exerts a downward force to the sensor ring  104 . 
         [0052]    In  FIG. 6 , non-linear members  113  and  114  of improved adjustment tab  110 A are each arranged to clasp at least one lever arm of lever spring  107 A. In  FIG. 6 , base portion  112  and extension  115  are behind clamp spring  111 .  FIG. 7A  shows a perspective view of improved adjustment tab  110 A which includes base portion  112 , non-linear member  113 , non-linear member  114  and extension  115 . Base portion  112  is substantially planar to contact the underneath surface of clamp spring  111 . In a preferred embodiment, base portion  112  is substantially cuboid in shape with rounded edges. Extension  115  protrudes upwardly or radially from base portion  112  to fit within correspondingly shaped aperture  111 A of clamp spring  111 . Non-linear members  113  and  114  emanate or radiate from opposing sides of base portion  112  in a direction orthogonal to the position of extension  115 . Non-linear member  113  mirrors non-linear member  114 . As described above, non-linear members  113  and  114  are substantially “S”-shaped. Preferably, improved adjustment tab  110 A is stamped of a single piece of material, for example, sheet metal. 
         [0053]    Due to the “S”-shape of non-linear members  113  and  114 , non-linear members  113  and  114  could have a spring-like force when a load is applied to them. This spring-like force could help secure improved adjustment tabs  110 A,  110 B, and  110 C to clamp spring  111 . Since base portion  112  has a width that is less than the width of clamp spring  111 , non-linear members  113  and  114  apply a force back onto clamp spring  111 . 
         [0054]      FIG. 7B  shows a bottom plan view of improved adjustment tab  110 A. Base portion  112  is substantially planar while non-linear members  113  and  114  are arcuate. Extension  115  is shown stamped inward; in  FIG. 7A , extension  115  is shown stamped upward. Non-linear members  113  and  114  are arm-like and operatively arranged to engage lever spring  107 A (shown in  FIG. 6 ) via hooks  113 A and  114 A. The overall mass of improved adjustment tab  110 A is approximately 2.15 grams, although it should be appreciated that the mass of improved adjustment tab  110 A may vary and is not intended to limit the scope of the claims. To install improved adjustment tab  110 A onto clamp spring  111 , a person would pull clamp spring  111  upwards and slide improved adjustment tab  110 A onto clamp spring  111  until extension  115  fits within correspondingly shaped aperture  111 A of clamp spring  111 . 
         [0055]    As shown in  FIG. 8 , clamp spring  111  includes correspondingly shaped aperture  111 A to accommodate extension  115  of improved adjustment tab  110 A. Improved adjustment tab  110 A is integrally engaged with clamp spring  111 . In a preferred embodiment, extension  115  has a shape that is rounded rectangular and aperture  111 A is correspondingly shaped. When improved adjustment tab  110 A is secured to clamp spring  111 , the adjustment tab/clamp spring assembly has center of mass A′, which is co-planar with clamp spring  111 . Specifically, center of mass A′ is approximately 4.74 mm from the optical center of mass along the abscissa shown in  FIG. 8  and approximately −0.016 mm from the optical center of mass along the ordinate shown in  FIG. 8 . Due to the arrangement of improved adjustment tab  110 A and clamp spring  111 , while clutch assembly  100  rotates about axis  101 , there is a significant reduction in the amount of unwanted outward rotation in the direction of the arrow shown in  FIG. 8 . The reduced mass of improved adjustment tab  110 A contributes to this reduction of unwanted outward rotation. 
         [0056]    Improved adjustment tab  210 A is illustrated in  FIGS. 9 ,  11  and  13 . The description regarding improved adjustment tab  110 A applies to improved adjustment tab  210 A except as provided. Non-linear members  213  and  214  each include an additional arcuate portion on the end opposite base portion  212 . The mass of improved adjustment tab  210 A is approximately 1.94 grams, although it should be appreciated that the mass of improved adjustment tab  210 A may vary and is not intended to limit the scope of the claims. 
         [0057]      FIG. 11  depicts improved adjustment tab  210 A within a portion of clutch assembly  200 . Non-linear members  213  and  214  are each arranged to clasp at least one of a plurality of lever arms  207 A. Clamp spring  211  includes aperture  211 A to accommodate extension  215 . Base portion  212  rests beneath clamp spring  211 . 
         [0058]    When improved adjustment tab  210 A is secured to clamp spring  211  (as shown in  FIG. 13 ), center of mass B is positioned approximately 4.74 mm from the optimal center of mass along the abscissa shown and approximately 0.05 mm from the optimal center of mass along the ordinate shown. 
         [0059]    Improved adjustment tab  310 A is shown in  FIGS. 10 ,  12  and  14 . The descriptions regarding improved adjustment tabs  110 A and  210 A apply to improved adjustment tab  310 A except as provided. Instead of an extension, improved adjustment tab  310 A includes “U”-shaped opening  315 . 
         [0060]      FIG. 12  shows improved adjustment tab  310 A secured to clamp spring  311  within a portion of clutch assembly  300 . Base portion  312  and “U”-shaped opening  315  are obscured by clamp spring  311 . Clamp spring  312  includes recessed portion  316  which includes protrusion  317 . Recessed portion  316  and protrusion  317  are arranged to engage “U”-shaped opening  315  of improved adjustment tab  310 A. Additionally, recessed portion  316  and protrusion  317  provide centering for the improved adjustment tab  310 A. Non-linear members  313  and  314  are each arranged to clasp at least one of a plurality of lever arms  307 A. 
         [0061]    The overall mass of improved adjustment tab  310 A is approximately 1.94 grams although it should be appreciated that the mass of improved adjustment tab  310 A may vary and is not intended to limit the scope of the claims. When improved adjustment tab  310 A is secured to clamp spring  311  (as shown in  FIG. 14 ), center of mass B′ is positioned approximately 4.72 mm from the optimal center of mass along the abscissa shown and approximately 0.01 mm from the optimal center of mass along the ordinate shown. 
         [0062]    A clutch assembly incorporating improved adjustment tabs  110 A,  210 A,  310 A can be actuated via electric or hydraulic means. 
         [0063]    It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           40  typical clutch assembly 
           41  axis 
           42  outer housing 
           43  central plate 
           44  adjuster ring 
           49 A rivet 
           49 B rivet 
           49 C rivet 
           49 D rivet 
           49 E rivet 
           49 F rivet 
           49 G rivet 
           49 H rivet 
           49 I rivet 
           50 A prior art adjustment tab 
           50 B prior art adjustment tab 
           50 C prior art adjustment tab 
           51  clamp spring 
           52 A screw 
           52 B screw 
           52 C screw 
           53 A bushing 
           54  sensor ring 
           55  top 
           56 A foot 
           56 B foot 
           57 A lever spring 
           57 B lever spring 
           58  transport lock 
           60  aperture 
         A center of mass 
         A′ center of mass 
         B center of mass 
         B′ center of mass 
         X abscissa 
         Y ordinate 
           100  clutch assembly 
           101  axis 
           102  outer housing 
           103  central plate 
           104  tension ring 
           105  adjuster ring 
           107 A lever spring 
           107 B lever spring 
           108  transport lock 
           110 A improved adjustment tab 
           110 B improved adjustment tab 
           110 C improved adjustment tab 
           111  clamp spring 
           111 A aperture 
           112  base portion 
           113  non-linear member 
           114  non-linear member 
           115  extension 
           200  clutch assembly 
           210 A adjustment tab 
           207 A lever arms 
           211  clamp spring 
           211 A aperture 
           212  base portion 
           213  non-linear member 
           213 A hook 
           214  non-linear member 
           214 A hook 
           215  extension 
           300  clutch assembly 
           307 A lever arms 
           311  clamp spring 
           310 A adjustment tab 
           312  base portion 
           313  non-linear member 
           313 A hook 
           314  non-linear member 
           314 A hook 
           315  “U” shaped opening 
           316  recessed portion 
           317  protrusion