Abstract:
A self-locking, twist &amp; lock, system for attachment of an engine flexplate to a torque converter mounting plate including a plurality of lugs carried on the end surface of the torque converter mounting plate in a circumferentially spaced-apart relationship to one another. A snap-lock spring retainer is releasably secured to each of the lugs. The flexplate has a plurality of retainer receivers in a circumferentially spaced-apart relation identical to the placement of the lugs. Each of the retainer receivers defining a retainer bar segment and openings for receiving the lugs and spring retainers. Each spring retainer has a flexible head portion adapted to engage a corresponding retainer bar segment to secure the plates together.

Description:
This invention relates generally to an engine flexplate assembly for a vehicle and more particularly to a self-locking system for connecting a torque converter assembly to a flexplate. 
     BACKGROUND OF THE INVENTION 
     Typically, a torque converter is connected to the engine&#39;s flexplate by a simple bolted connection. The resultant assembly process consists of lining up the flexplate and the torque converter plate, hand-starting several threaded fasteners in aligned holes in the torque converter and in the flexplate, and tightening the fasteners with an impact wrench. Because of space restrictions and access only at a lower position, it is necessary to rotate the engine (and the attached flexplate) and stop at a position to tighten the fasteners one at a time. Considerable time is required to accomplish this, depending upon the number of fasteners involved. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a plurality of lugs are welded or otherwise secured to either the flexplate or the torque converter mounting plate. In a preferred arrangement, the lugs are welded to the torque converter mounting plate. Snap-lock type spring retainers are attached to the lugs to form a lock assembly. Each spring retainer has a head portion which is adapted to snap into engagement with a retainer bar portion of the flexplate for securing the two together. This locking action only requires a few degrees of rotation between the torque converter and the flexplate to cause all the lock assemblies to engage in a locking arrangement simultaneously and automatically. The snap-lock spring retainers are secured to the lugs by readily releasable fasteners, making it possible to pre-assemble the retainers to the torque converter before final assembly of the unit to the flexplate. This attachment system of the spring retainers also permits an easily accomplished release of the spring retainers to disconnect the torque converter from the flexplate for service replacement or repair. 
     Further in accordance with the invention, the lug mounts are located on the torque converter mounting plate in circumferentially spaced-apart relation to one another in a circle of given diameter which is concentric with the central axis of the torque converter. The flexplate has a plurality of retainer bars segments, equal in number to the number of lugs and spring retainers. Each bar segment is disposed in a circle of the same given diameter which is concentric with the central axis of the flexplate in the same equally, circumferentially spaced-apart relationship as the lugs and spring retainers. During assembly of the torque converter to the flexplate, relative rotation between the torque converter and the flexplate causes each snap-lock spring retainer to simultaneously engage the associated bar segment on the flexplate to secure the two units together. 
     Preferably, each snap-lock spring retainer has a flat body portion which engages an associated flat portion of a lug. A locking head portion then projects away from the flat body portion of the lug to form a cantilevered lock portion. The corresponding bar segment on the flexplate to which the lock portion engages is defined by a pair of adjacent slots formed therethrough. The bar segments extend in a radial direction of the flexplate and between the pair of adjacent slots. Thus the slot pair forms a first and a second opening circumferentially at opposite sides of the retainer bar segment. The cantilevered lock portion of each of the spring retainers is first inserted through the first opening, and then the torque converter is rotated relative to the flexplate causing the cantilevered lock portions to flex as each moves across an associated bar segment. Finally, a hooked end portion of the cantilevered lock portion snaps over the bar segment to retain the units. 
     One object of this invention is to provide a system for attaching a flexplate to a torque converter plate having the foregoing features and capabilities. 
     Another object is to provide a system for attaching a torque converter mounting plate to a flexplate which system consists of a relatively few simple parts, and is capable of connecting the two plates together quickly and easily upon only a slight relative rotation between the of torque converter and the flexplate. 
     These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an engine flexplate and torque converter mounting plate attached together by the subject system of snap-lock spring retainers engaging retainer bar segments; and 
     FIG. 2 is an perspective, exploded view of the assembly shown in FIG. 1; and 
     FIG. 3 is a perspective view of the flexplate and the torque converter mounting plate prior to attachment together and with two of the spring retainers mounted to lug portions of the mounting plate; and 
     FIG. 4 is a perspective, exploded view of a single lug, snap-lock spring retainer and the attaching bolt; and 
     FIG. 5 is a fragmentary sectioned view of portions of the flexplate and torque converter mounting plate, showing the subject lug supported snap-lock spring retainer in relation to a retainer bar segment prior to a rotative attachment of the torque converter mounting plate and the flexplate; and 
     FIG. 6 is a view similar to FIG. 5 but illustrating the lug supported snap-lock spring retainer in elevation; and 
     FIG. 7 is a view similar to FIG. 6 showing the snap-lock spring retainer moved to a locked position where it engages a retainer bar segment after the torque converter mounting plate is rotated relative to the flexplate; and 
     FIG. 8 is an exploded view like FIG. 4, but showing a modification; and 
     FIG. 9 is a view similar to FIG. 6, showing the modification of FIG. 8 in a pre-locking position relative to a retainer bar segment prior to the relative rotation of the torque converter relative to the flexplate; and 
     FIG. 10 is a view similar to FIG. 7, showing the modification of FIG. 8 in a locked relation to a retainer bar segment after rotation of the torque converter relative to the flexplate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now more particularly to FIGS. 1-7, a circular flexible plate or flexplate  10  is shown attached to a circular torque converter mounting plate  12 . The two members  10 ,  12  are releasably secured together in parallel face-to-face relationship by a self-locking system including: a plurality of lugs  16  carried on a surface of the torque converter mounting plate  12 ; snap-lock spring retainers  18  attached to the lugs; and retainers in the form of bar segments  20  formed by the flexplate  10 . 
     More particularly, a plurality of the lugs  16  are formed on a face or surface  22  of the torque converter mounting plate  12 . Face  22  faces flexplate  20 . In the subject embodiment, six lugs are carried by the plate  12  but the number of lugs may be changed, as desired. The lugs are welded or otherwise secured to the face  22  of the torque converter plate in a circumferentially spaced-apart relationship and as defined by a circle concentric with the central axis  24  of the torque converter plate. Preferrably, the lugs  16  are all identical but do not have to be identical. Each of the lugs is elongated in a circumferential direction and defines a flat outer surface  26  extending parallel to the face  22  of the torque converter plate  12 . The flat surface  26  has a threaded bore  30  and, spaced circumferentially from the bore, a locating feature such as stud  32  projecting axially outwardly from the flat surface  26 . Each lug also has sides  34  and  36  extending perpendicular to the surface  26  and parallel to a line connecting the bore  30  and stud  32 . A pair of surfaces or shoulders  37  extend at a lower elevation relative surface  26  and radially from each side surface  34 ,  36 . 
     A snap-lock spring retainer  18  is mounted to the required number of lugs  16 . Each snap-lock spring retainer has a main body portion  42  and an integral head portion  44  extending from the main body portion. The body portion  42  is elongated and has a substantially flat central portion with flanges  45  along each side and extending perpendicular thereto. The central portion has two longitudinally spaced holes  46  and  48  formed therethrough. The head portion  44  has an integral end extension which is folded over in an open loop. The snap-lock spring retainer  18  is made of a relatively stiff material such as spring steel which is strong but resilient and sufficiently flexible to flex readily as will be detailed hereinafter. 
     The snap-lock spring retainer  18  is mounted on an associated lug  16  by aligning hole  48  with the stud  32  and extending the retainer over a stud  32 . This effectively aligns the bore  46  with the threaded bore  30  of the lug. The bolt fastener  50  is then inserted through hole  46  in the retainer body  42  and into the threaded bore  30 . Additionally, flanges  45  of retainer body  42  embrace the sides  34 ,  36  of the lug align holes  46 ,  48  with the bore  30  and stud  32 . 
     As best shown in FIG. 3, the flexplate  10  presents a plurality of the retainer bar segments  20 , equal in number to the lugs and spring retainers of the plate  12 . The bar segments  20  are disposed in a circle of the same radius as the circle of the lugs  16  and the circle is concentric with the central axis  62  of the flexplate  10 . The retainer bar segments  20  are in the same circumferentially spaced-apart relation as the lugs  16 . More specifically, a plurality of slot arrangements  70  are formed through the flexplate, each slot arrangement consists of a pair of slightly circumferentially spaced openings, one slot arrangement being associated with each retainer bar segment  20 . Each slot arrangement  70  includes an opening large enough to accommodate the entire length and width of a spring retainer  18 . Each retainer bar segment  20  is actually defined between the large opening which described in the previous sentence and a smaller opening which together define the slot arrangement  70 . In other words, each bar segment  20  extends radially across and between the two openings which form the slotted arrangement. The bar segment  20  essentially divides the slot arrangement  70  into the first and second circumferentially space-apart openings  76  and  78 . The retainer bar segments  20  are integral with the flexplate  10 . 
     When it is desired to attach the torque converter plate  12  to the flexplate  10 , the torque converter is brought axially toward the flexplate so that they are in parallel face-to-face relation with respective central axes  24 ,  62  aligned. The torque converter plate  12  is adjusted so that the lug supported spring retainers  18  register or are aligned with the first openings  76  in the flexplate. After the two units are moved close together in an axial direction, the lug-supported spring retainers project through the first openings  76  as shown in FIGS. 5 and 6. In this pre-assembly position, the retainer&#39;s head  44  also projects into the first opening  76 . However, the head  44  has an end portion with a generally loop-like configuration with a surface angled relative to the adjacent retainer bar segment  20 . This surface serves as camming surface  80 . 
     To complete the assembly of the two units together, the torque converter plate  12  is then rotated from the position of FIGS. 5 and 6 to the position shown in FIG.  7 . As the torque converter plate  12  is rotated, the head portion&#39;s camming surface  80  is resiliently sprung or flexed axially outwardly by its engagement with the retainer bar  20 . On further relative rotation the end of the head portion  44  snaps over the retainer bar  20  and lodges or settles into the second opening  78  in the flexplate to lock the units together. 
     Because of the circumferential spacing of the lug supported retainers  18  and the retainer bars  20 , all of the head portions  44  of the snap-lock spring retainers  18  snap into place in the second openings  78 . 
     When it is desired to separate the two units from one another for service or replacement, the threaded fastener  50  can be removed which disconnects each spring retainer  18  from its lug support. The plate  12  and lugs are then readily withdrawn from openings  76  in the flexplate. 
     In FIG. 8-10, a modified snap-lock spring retainer  84  mounted on a lug  82  is illustrated. A plurality of the lugs  82  are welded to the face  22  of the torque converter plate  12  in the same spaced relationship as described in connection with FIGS. 1-7. Each lug  82  is elongated circumferentially and has a flat top or outer surface  86  extending parallel to face  22  of the torque converter plate  12 . The surface  86  has a threaded bore  88  and, spaced circumferentially from the bore  88 , a locating feature such as the stud  90  projecting axially outwardly from the surface  86 . 
     One end of each lug  82  has a stepped configuration with inner and outer end surfaces  98  and  100  extending perpendicular to surface  86 . A shoulder  102  is formed between the surfaces  98 ,  100 . 
     A snap-lock spring retainer  84  is mounted on each of the lugs  82 . Each snap-lock spring retainer  84  is made from an elongated strip of spring steel as with the first embodiment but here the material is doubled over along itself so that the main body portion  104  has two end portions compressed together in overlying surface-to-surface contact. The two end portions are connected together at the leftward end of the body by an intermediate portion which is in the form of a closed loop. The closed loop provides a head portion  110  corresponding to the head portion  44  of the first embodiment. 
     A threaded fastener  112  extends through a hole  114  formed in the retainer&#39;s body portion  104  and threads into bore  88  provided by the lug  82 . The stud  90  projects into a hole  116  formed in the retainer&#39;s body portion  104  to releasably secure align the snap-lock spring retainer  84  on the lug. 
     It will be understood that the torque connector plate  12  with lugs  82  and attached snap-lock spring retainers  84  engage the retainer bar segments  20  of the flexplate in the same manner as previously described in connection with the embodiment of FIGS. 1-7. The head portion  110  will be seen to have a camming surface  120 , similar to the camming surface  80  in the previous embodiment. The camming surface  120  engages the retainer bar  20  when plates  12  is rotated relative to plate  10  from the position shown in FIG. 9 to the position shown in FIG.  10 . As the two plates move relative to one another, the head portion  110  springs or flexes axially outward from the surface of plate  12  and moves past the retainer bar  20 . Subsequently, it snaps into the second opening  78  to lock the two plates together. 
     The procedure to lock the two plates  10 ,  12  together using modified spring retainer  84  is the same as for the embodiment of FIGS. 1-7. However, it should be noted that when the plates  10 ,  12  are finally in the locked position shown in FIG. 10, one side edge (rightward edge) of each retainer bar  20  engages the inner surface  98  and the shoulder  102  of the associated lug  82 . This positively and accurately locates the lugs in relation to the retainer bars.