Abstract:
A spring device comprising at least one annular support plate defining a ring with a central axis; a plurality of circumferentially spaced, parallel oriented coil springs disposed about the at least one annular plate; and, a plurality of lock assemblies spaced about the plate. Each of the lock assemblies being in position within a spring cavity of one of the coil springs to allow additional springs to be provided on the spring device. In addition, the lock assemblies are dimensioned so that the coil spring is retained in a prestressed condition.

Description:
This application claims the benefit, as a divisional application, of U.S. application Ser. No. 10/259,695, filed on Sep. 30, 2002, the specification of which is incorporated herein in its entirety. 

   The present invention relates to a spring device and more particularly to a spring device of the type used in automatic transmissions for motor vehicles. 
   INCORPORATION BY REFERENCE 
   Automatic transmissions for vehicles often include a plurality of coil springs that are adapted to apply a biasing force against clutch plates that control the engagement of various gears in the transmission. These coil springs are assembled in a ring shaped device comprising two annular plates having a multiplicity of circumferentially spaced, parallel compression coil springs mounted therebetween. Such a ring shaped spring device is disclosed in Orlowski U.S. Pat. No. 5,306,086, which is incorporated by reference herein as the basic background to which the present invention is directed. A ring shaped spring device is also disclosed in pending application Ser. No. 10/078,465 filed on Feb. 2, 2002 which is incorporated by reference herein as the basic background to which the present invention is directed. 
   BACKGROUND OF INVENTION 
   In the ring shaped spring device disclosed in Orlowski, there is a pair of spaced apart first and second annular support plates defining the ring shape of the spring device. A plurality of circumferentially spaced parallely oriented coil springs are disposed between the annular plates so that vertical movement of one plate toward the other compresses the springs. To interconnect the plates, an integral hook is formed in one plate and a loop is integrally formed in the other plate. The hook and loop are designed so that the device can be assembled by merely locating the various coil springs and then pressing one plate toward the other. The hook snaps over the loop to lock the plates together, with the coil springs partially compressed. However, when assembled in a transmission, the ring shaped spring device is compressed further so that the hook actually disengages the loop. Consequently, during repetitive operation of the spring assembly over many years, the individual coil springs can become canted in a manner to reduce the spring constant and cause damage and/or unintended biasing forces. By compressing the spring device for shifting the gears of the automatic transmission, distortion of the coil springs in the annular direction is magnified. Consequently, the prior ring shaped spring device, as shown in Orlowski only employs the concept of integral interconnecting elements and does not address the problem of controlling the annular movement of the spaced plates during long term operation of the spring device. Orlowski also must remove four of his coil springs to provide space for integral hooks used to maintain the plates relative to one another. As a result, the force produced by the Orlowski spring device is not maximized and is not balanced. The spring assembly in copending application Ser. No. 10/078,465 is a different mechanism to overcome the deficiency of Orlowski regarding circumferential shifting. But, this design uses spaces which should accept coil springs. 
   THE INVENTION 
   The present invention relates to a ring-shaped spring device as shown in Orlowski wherein there are a plurality of locking assemblies located at circumferentially spaced positions around the ring that are each within one of the coil spring&#39;s center passage. In this respect each of these lock assemblies includes a first element extending from one of the plates toward the other plate, a second element extending in the opposite direction from the other plate to form a generally sliding contact between the first and second elements as the spaced plates move vertically to compress and release the coil springs. The first and second elements are sized and shaped to fit within the center passage of the coil spring. This configuration maximizes the force produced by the ring shaped spring device and balances the circumferentially extending spring action. 
   In accordance with another aspect of the present invention, the first and second elements or tabs include a guiding mechanism to restrict annular movement at the plates relative to one another. The first tab having a guide slot with a given width and which extends in a direction perpendicular to the plates. The second tab having a hook shaped guide member which extends through the guide slot to restrict the vertical movement between the two plates. The width of the hook corresponds with the width of the slot which provides the guiding mechanism between the two plates. The structure assembly procedure and operation of the present invention is different than the ring shaped spring device in Orlowski. These added features further result in the advantage of being capable of maintaining the proper annular orientation between the spaced plates during long term operation of the spring device in an automatic transmission. 
   Still another aspect of the present invention, the guide slot has an end remote from the plate from which the second tab extends. The distance of this end from the plate maintains the coil springs in a compressed or prestressed condition when the device is assembled. 
   Yet another aspect of the present invention, by providing a tab which is sized to fit within the center passage of a coil spring, one of the annular support plates can be omitted. In its place are disk shaped pressure plates for each coil spring which reduces weight. Each of the disk plates includes a locking tab surface that maintains the disk plate and spring relative to the remaining annular plate. 
   Even yet another aspect of the present invention, there are an even number of locking assemblies around the circumference of the annular plates. One group of locking assemblies has the first tab extending from the first plate and the second group has the first tab extending from the second plate. By using two groups of locking assemblies, the tabs of a plate alternate between a tab with the guide slot and a tab with the hook. The tabs may be integrally formed in the guide plates as in Orlowski. In the one embodiment, four locking assemblies are used wherein the integral tabs at the twelve o&#39;clock position and six o&#39;clock position have one construction and the tabs at the three o&#39;clock position and nine o&#39;clock position have the opposite configuration. By merely indexing the plates 90°, identical plates can be used in constructing the ring shaped spring device. 
   Yet a further aspect of the present invention relates to utilizing molded tab components which incorporate one-way barbs or locking tabs to maintain the plates relative to one another. In this respect, one of the annular plates includes a plurality of spaced receptacles corresponding to the position of the coil springs. The receptacles are sized so that the coil springs fit about the receptacle. The other annular ring includes posts which also correspond to the position and number of coil springs. The receptacle is shaped to receive the post and includes one-way or locking barbs such that once the post enters the receptacle, it can not be removed. 
   Another aspect of the present invention involves spring tabs to locate the coil springs around the annular plates. These spring tabs are lanced from the edge of the annular plates and are bent downwardly at circumferentially spaced locations around the plates. The tabs are bent downwardly from a point generally at the midpoint of the plates, whereby the coil springs are located by the tabs in or near the center of the annular plates. This configuration allows the spring tabs to be produced by a simple punch press operation that first lances and then bends the tabs relative to the plate. This operation is much simpler than the complex bending operation required in Orlowski. 
   An object of the present invention is the provision of an improved ring-shaped spring device having two annular plates used to capture and locate circumferentially spaced coil springs, wherein the spring device guides the movement of the annular plates as the springs are compressed and/or released and solving the deficiencies of Orlowski U.S. Pat. No. 5,306,086. 
   Another object of the present invention is the provision of a spring device which utilizes locking assemblies that fit within the center passage of one of the coil springs so as to maximize the number of springs that can be utilized and balancing the spring action around the assembly. 
   Yet a further object of the present invention is the provision of a ring-shaped spring device wherein spaced annular plates are held together by lock assemblies having members that limit the movement between the plates to a generally vertical sliding movement as the plates move vertically to compress and/or release the coil springs, so the plates are fixed in a circumferential direction. 
   Even yet a further object of the present invention is the provision of replacing one annular ring with independent disk shaped pressure plates corresponding to each coil spring. 
   Another aspect of the present invention is the provision of utilizing molded components having one-way or locking barbs that can be easily snap-fitted together. 
   Even yet another object of the present invention is the provision of eliminating one annular ring by utilizing coil spring which can interengage with the other annular ring. 
   These and other objects and advantages will become apparent from the following description taken together with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a top plan view of the ring shaped spring device constructed in accordance with an embodiment of the present invention; 
       FIG. 2  is an enlarged cross-sectional view taken generally along line  2 — 2  of  FIG. 1 ; 
       FIG. 2A  is an enlarged cross-sectional view similar to  FIG. 2  showing the top hook tab formed from material near the inner rim of top annular ring; 
       FIG. 3  is a cross-sectional view taken generally along line  3 — 3  of  FIG. 2 ; 
       FIG. 3A  is a cross-sectional view taken generally along line  3 A— 3 A of  FIG. 2A ; 
       FIG. 4  is an enlarged exploded partial view of the spring device shown in  FIG. 1 ; 
       FIG. 5  is an enlarged cross-sectional view of another embodiment of a ring shaped spring device according to the present invention; 
       FIG. 6  is a cross-sectional view taken generally along line  6 — 6  of  FIG. 5 ; 
       FIG. 7  is a top plan view showing another embodiment of a ring shaped spring device according to the present invention; 
       FIG. 8  is an enlarged cross-sectional view taken generally along line  8 — 8  of  FIG. 7 ; 
       FIG. 9  is an enlarged cross-sectional view taken generally along line  9 — 9  of  FIG. 7 ; 
       FIG. 10  is an enlarged exploded partial perspective view of the ring-shaped device shown in  FIG. 7 ; 
       FIG. 11  is a top plan view of yet another embodiment of a ring shaped spring device according to the present invention; 
       FIG. 12  is an enlarged cross-sectional view taken generally along line  12 — 12  of  FIG. 11 ; 
       FIG. 13  is an enlarged cross-sectional view taken generally along line  13 — 13  of  FIG. 11 ; 
       FIG. 14  is an enlarged cross-sectional view taken generally along line  14 — 14  of  FIG. 11 ; 
       FIG. 15  is an enlarged cross-sectional view taken generally along line  15 — 15  of FIG.  11 ; 
       FIG. 16  is an enlarged exploded partial perspective view of the spring device shown in  FIG. 11 ; 
       FIG. 17  is a top plan view of even yet another embodiment of a spring shaped spring device according to the present invention; 
       FIG. 18  is an enlarge cross-sectional view taken generally along line  18 — 18  of  FIG. 17 ; 
       FIG. 19  is a cross-sectional view taken generally along line  19 — 19  of  FIG. 18 ; 
       FIG. 20  is an exploded partial perspective view of the spring device shown in  FIG. 17 ; 
       FIG. 21  is a top plan view of still yet a further embodiment of a ring shaped spring device according to the present invention; 
       FIG. 22  is an enlarged cross-sectional view taken generally along line  22 — 22  of  FIG. 21 ; and, 
       FIG. 23  is an exploded partial perspective view of the spring device shown in  FIG. 21 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring now to the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and not for the purpose of limiting same,  FIGS. 1 ,  2 ,  3  and  4  show a ring shaped spring device  8  having annular spaced-apart plates  10 ,  12  with outer rims  14 ,  16 , respectively, and inner edges  15 ,  17 . Plates  10 ,  12  are coaxial to axis  18  and include spring tabs  20  of plate  10  and spring tabs  22  of plate  12 . The tabs, sometimes called “elements”, are lanced from a center portion of its respective plate and are bent to locate at circumferentially spaced positions a number of coil springs  30 . The spring tabs  20 ,  22  have spaced distal edges  20   a ,  22   a  facing one another and have a length such that there is a gap between edges  20   a ,  22   a  when device  8  as a whole is in a free state. Edges  20   a ,  22   a  engage one another to limit the vertical movement of plates  10 ,  12  toward one another. The widths W of the spring tabs are just slightly smaller than the diameters of passages  32  of springs  30 . Any number of tabs and springs can be circumferentially spaced around plates  10 ,  12 . In a preferred embodiment, twenty-four springs are employed and are equally spaced around plates  10 ,  12 . The tabs or elements extend through the springs so there is no circumferential gap in the circular array of coil springs. 
   Four lock assemblies  40 ,  42 ,  44  and  46  are utilized to maintain plates  10 ,  12  relative to one another and are positioned within center passages  32 A,  32 B,  32 C and  32 D of coil springs  30 A,  30 B,  30 C and  30 D respectively. By positioning the lock assemblies within the coil springs, four additional coil springs can be utilized thereby increasing the possible overall spring force of spring device  8  without changing the design of coil springs  30 . All lock assemblies  40 ,  42 ,  44  and  46  are essentially the same, however, the orientation of the assemblies is alternated one lock assembly to the next which allows plates  10 ,  12  to be identical. In this respect, while each lock assembly is structurally the same, lock assemblies  40 ,  44  are oriented in one direction and lock assemblies  42 ,  46  are oriented in the opposite direction. Plates  10 ,  12  are merely positioned facing each other and are rotated 90° relative to one another about axis  18  to properly align lock assemblies  40 ,  42 ,  44  and  46 . The advantage of this concept is that by using identical plates, manufacturing and inventory costs can be reduced. 
   Since all lock assemblies  40 ,  42 ,  44  and  46  are structurally the same, only lock assembly  40  will be described in detail and this description applies to the other lock assemblies  42 ,  44  and  46 . However, as stated above, assemblies  42 ,  46  are oriented differently. Lock assembly  40  includes hook tabs  50 ,  52  which are provided on the opposite plates  10 ,  12 . Tabs  50 ,  52  are created by forming a lanced portion of plates  10 ,  12 , respectively, wherein tabs  50 ,  52  are still attached to plates  10 ,  12 , at bases edges  54 ,  56  respectively. Turning to tab  50 , it is lanced from an outer portion of plate  10  such that there is a gap in plate  10  from base edge  54  which extends radially outwardly to rim  14 . Tab  50  is bent at base edge  54  at a 90 degree angle from plate  10  toward plate  12  and includes a base portion  66 , an extension  68  and a distal end  58 . Tab  50  further includes a hook  62  on distal end  58  which is opened toward outer rim  14 . Tab  52  is lanced from an inner portion of plate  12  such that there is a gap in ring  12  from base edge  56  which extends radially inwardly to edge  17 . Tab  52  is bent at base edge  56  at a 90 degree angle from plate  12  towards plate  10  and includes base portion  70 , an extension  72  and a distal end  60 . Tab  52  further includes a hook  64  on distal end  60  which is opened toward inner edge  17 . When plates  10 ,  12  are move vertically toward one another, hooks  62 ,  64  pass over each other and then prevent the plates  10 ,  12  from being separated vertically. As a result, plates  10 ,  12  can move vertically relative to one another, however, hooks  62 ,  64  prevent separation of the plates. The length of tabs  50 ,  52  determine the free-state height of device  8  as a whole and maintain the springs in a prestressed condition. In this respect coil springs  30  have a free-state spring height which is different than the overall free-state height of device  8 . The free-state spring height is achieved when coil springs  30  are unstressed and allowed to extend to a maximum spring height (not shown). The gap between plates  10 ,  12  is less than the free-state height for coil springs  30  when hooks  62 ,  64  are interengaging with one another. Accordingly, springs  30  are exerting a force against plates  10 ,  12  even when the overall spring device  8  is in its unstressed or free-state condition. When an external force is applied to spring device  8 , plates  10 ,  12  move vertically downwardly toward one another and hooks  62 ,  64  disengage. As discussed above, the downward vertical motion is limited by edges  20   a,    22   a  of spring tabs  20 ,  22  respectively. 
   In the following discussions concerning other embodiments, the components of the spring device which remain the same, as discussed above, will include the same reference numbers as above. 
   Referring to  FIGS. 2A and 3A , Lock assembly  40   a  is shown which works the same way as lock assembly  40  except it includes hook tabs  52  and  50   a.  While tab  52  is the same as described above, tab  50   a  is lanced from an inner portion of plate  10   a  such that there is a gap in ring  10   a  from base edge  54   a  which extends radially inwardly to edge  15 . Tab  50   a  is bent at base at a 90 degree angle from plate  10   a  toward plate  12 . Tab  50   a  is bent at base edge  54   a  and includes a distal end  58   a  with a hook  62   a  which is opened toward outer rim  14  just like hook  62 . The only difference being that tab  50   a  is formed from an inner portion of plate  10   a  while tab  50  is formed from the outer portion. In similar fashion as assembly  40 , when plates  10   a ,  12  are move vertically toward one another, hooks  62   a ,  64  pass over each other and then prevent the plates  10   a ,  12  from being separated vertically. 
   Referring to  FIGS. 5 and 6 , a ring shaped spring device  100  is shown which is essentially the same as device  8  above except for a modification to the locking assemblies. More particularly, spring device  100  includes annular spaced-apart plates  10 ,  102  with outer rims  14 ,  104 , respectively. Plates  10 ,  102  are coaxial to axis  18  and include spring tabs  20  (not shown) of plate  10  and spring tabs  22  (not shown) of plate  102  which are configured the same as above and therefore will not be discussed in detail. Any number of tabs and springs can be circumferentially spaced around plates  10 ,  102 . In a preferred embodiment, twenty-four springs are employed and are equally spaced around plates  10 ,  102 . 
   Four lock assemblies  110 ,  112 ,  114  and  116  (only  110  is shown) are utilized to maintain plates  10 ,  102  relative to one another. As with device  8 , assemblies  110 ,  112 ,  114  and  116  are structurally the same except that they are oriented differently to allow plates  10 ,  102  to be identical. Therefore only assembly  110  will be described in detail and this description applies to the other lock assemblies  112 ,  114  and  116 . Assembly  110  is positioned within center passage  32 A of coil spring  30 A and includes hook tab  50 , described above, and slot tab  122 . Slot tab  122  is formed from an inner portion of plate  102  and extends from a base edge  124  to a distal end  126 . Tab  122  extends at a 90° angle from plate  102  toward plate  10  and has a maximum width  128  allowing it to fit within center passage  32 A. Extending vertically in tab  122  is an elongated slot  130  having a width  132 , a length  134  and a slot edge  136  near distal end  126 . Side edges  138 ,  140  are essentially parallel to one another and extend from either side of slot edge  136  toward plate  102 . Tab hook  62  along with extension  68  have essentially a common width which is slightly smaller than slot width  132  such that hook  62  can extend through slot  130 . Accordingly, when plates  10 ,  102  are assembled, hook  62  first engages slot tab  122  and then enters slot  130 . Once in slot  130 , the engagement between hook  62  and slot edge  136  prevents separation of plates  10 ,  102 . In addition, the length of tab  50  and slot  130  determine the free-state height of device  100  as a whole and maintains springs  30  in a prestressed condition. Movement of plates  10  and  102  relative to one another about axis  18  is controlled by the engagement between hook  62  and slot edges  138 ,  140 . In this respect, hook  62  has hook edges  142 ,  144  and rotation is prevented in one direction by the engagement between slot edge  138  and hook edge  142  and in the other direction by the engagement between hook edge  144  and slot edge  140 . 
   Referring now to  FIGS. 7–10 , a ring shaped spring device  200  is shown which includes only one annular plate  202 . Plate  202  includes an outer rim  204  and an inner edge  205 . Plate  202  further includes spring tabs  206  which are lanced from an inner portion of plate  202  wherein tabs  206  are still attached to plate  202  at base edges  207 . In this respect, tabs  206  are formed by an inner portion of plate  202  such that there is a gap in plate  202  from base edge  207  which extends radially inwardly to edge  205 . Tabs  206  are bent at a 90 degree angle at base edge  207  from plate  202 . The widths W of the spring tabs are smaller than the diameters of the passages  208  of springs  210 . Any number of tabs and springs can be circumferentially spaced around plate  202 . In a preferred embodiment, twenty-four springs are employed and they are equally spaced around plate  202 . 
   Each spring tab  206  includes a vertically extending slot  212  having a top edge  214 , a bottom edge  216  and parallel side edges  218  and  220 . Each spring  210 , is made from a single wire  228  and includes a bottom edge  230  which rests on plate  202  and a top edge  232  spaced from bottom edge  230 . Spring  210  further includes extension  234  which is a continuation of wire  228  and which extends downwardly into center passage  208 . At the end of extension  234  is a hook  238  shaped and sized to enter slot  212 . Spring  210  is assembled to plate  202  by urging spring  210  over tab  206  and partially compressing spring  210  until hook  238  enters slot  212 . Once hook  238  enters slot  212  it maintains spring  210  relative to plate  202  in a prestressed condition with spring bottom  230  engaging plate  202 . As spring  210  is compressed by the transmission, hook  238  rides in slot  212  between top and bottom edges  214 ,  216  respectively. 
   Referring now to  FIGS. 11–16 , yet even another embodiment is shown. Shown is a ring shaped spring device  300  having annular spaced apart plates  302 ,  304  with outer rims  306 ,  308 , and inner edges  307 ,  309 , respectively. Device  300  includes spring tabs  310  for plate  302  and spring tabs  312  for plate  304  which are each lanced from an inner portion of plates  302 ,  304 , respectively, wherein tabs  310  are attached to plate  302  at bases edges  314  and tabs  312  are attached to plate  304  at base edges  316 . In this respect, tabs  310  are formed from an inner portion of the plates between base edges  314 ,  316  and inner edges  307 ,  309  respectively. Tabs  310 ,  312  are bent at a 90 degree angle at base edges  314 ,  316 . The widths W of the spring tabs are smaller than the diameters of passages  32  of springs  30 . Any number of tabs and springs can be circumferentially spaced around plates  302 ,  304 . In a preferred embodiment, twenty-four springs are employed and are equally spaced around plates  302 ,  304 . Spring tabs  310 ,  312  have spaced distal edges  317 ,  318  facing one another and have a length such that there is a gap between edges  317  and  318  when device  300  as a whole is in a free state. Edges  317 ,  318  engage one another to limit the vertical movement of plates  302 ,  304  toward one another. 
   Four lock assemblies  320 ,  322 ,  324  and  326  are positioned about plates  302 ,  304 . While four such assemblies are shown, as with the other embodiments, a different number of assemblies could be utilized. As with previous embodiments, assemblies  320 ,  322 ,  324  and  326  are structurally the same except that they could be oriented differently to allow plates  302 ,  304  to be identical. Therefore only assembly  320  will be described in detail and this description applies to the other lock assemblies  322 ,  324  and  326 . Referring with particular reference to  FIGS. 14 ,  15  and  16 , lock assembly  320  includes a hook tab  350  and a notch tab  352 . Tabs  350 ,  352  are created by forming a lanced portion of plates  302 ,  304 , respectively, wherein tabes  350 ,  352  are still attached to plates  302 ,  304  at bases edges  354 ,  356  respectively. Turning to tab  350 , it is lanced from an inner portion of plate  302  such that there is a gap in plate  302  from base edge  354  to inner edge  307 . Tab  350  is bent at base edge  354  ninety degrees from plate  302  toward plate  304  and includes a base portion  358 , an extension  360  and a distal end  362 . Extension  360  has a width which is approximately half the width of base portion  358  and further, extension  360  extends from one side of base portion  358  thereby making hook tab  350  L-shaped. Tab  350  further includes a hook  364  on distal end  362  which is opened toward inner edge  307 . Tab  352  is lanced from an inner portion of plate  304  such that there is a gap in ring  304  from base edge  356  to edge  309 . Tab  352  is bent at base edge  356  ninety degrees from plate  304  toward plate  302  and is essentially C-shaped having outer side edges  366 ,  368  which extend from plate  304  towards distal end  370  of tab  352 . Side edge  368  includes a notch  372  having parallel notch edges  374 ,  376  that are joined by vertical notch edge  378 . The length of notch edges  374 ,  376  corresponds with the width of hook  364 . With particular reference to  FIG. 15 , by utilizing L-shaped hook tab  350  and C-shaped notch tab  352 , assembly  320  can fit within spring cavity  32  and can be assembled without forcing hook  364  to deform in order to pass over its engagement point on notch tab  352 . In this respect, while within cavity  32 , hook  364  can be manipulated to pass next to edge  368  and then to be positioned within notch  372 . As hook  364  is being manipulated into notch  372 , spring  30  is partially compressed. Once in notch  372 , spring  30  forces plates  302  and  304  away from one another until hook  364  engages edge  374 . 
   Referring now to  FIGS. 17–20 , a ring shaped spring device  400  is shown which includes annular spaced apart plates  402 ,  404  with outer rims  406 ,  408  and inner edges  407 ,  409 , respectively. Spring device  400  is shown to include twenty-four lock assemblies  410 , however, it should be noted that less than twenty-four lock assemblies could be used and less than twenty-four coil springs  30  could be used. However, it is preferred that all twenty-four springs  30  are used in connection with twenty-four lock assemblies  410 . Lock assemblies  410  are all identical and each includes a receptacle  412  and a post  414 . Receptacle  412  is cylindrical with a base end  420  secured to plate  404  and which extends toward plate  402 . Receptacle  412  has a distal end  422  spaced from end  420  that includes an opening  424  to an inner portion  428 . Receptacle  412  further includes several barbs  426  that extend downwardly into inner portion  428 . Post  414  includes a base  430  connected to plate  402  and extends toward plate  404 . In addition, post  414  includes a tapered lead  432  which is shaped to urge barbs  426  outwardly and allow a portion of post  414  to enter inner portion  428 . Post  414  further include locking groove  434  having a cylindrical portion  436  and a frustum conical portion  438  adjacent to cylindrical portion  436 . As a result, once tapered lead  432  urges barbs  426  outwardly and allows the end of post  414  to enter inner portion  428 , barbs  426  spring into locking groove  434  thereby retaining post  414  relative to receptacle  412 . Cylindrical portion  436  provides for the compression of spring  30  by allowing post  414  to move downwardly into inner portion  428 . However, barbs  426  do not allow post  414  completely pull out of inner portion  428 . Furthermore, the vertical dimensions of post  414  and receptacle  412  are such that when barbs  426  engage edge  440 , springs  30  remain in a prestressed condition. In addition, the engagement between the post and the receptacle prevent rotational movement of plate  402  relative to plate  404  about axis  18 . 
   Referring to  FIGS. 21–23 , a ring shaped spring device  500  is shown which includes only a single annular plate  404  as described above. Spring device  500  further includes twenty-four receptacles  412  which are the same as described above with respect to spring device  400 . However, device  500  includes twenty four independent post assemblies  508 . While each post assembly  508  includes posts  414  as described above, each post assembly  508  is joined to a post disk  510  that has a diameter greater than the outer diameter of springs  30 . This results in each post assembly  508  moving independent of one another. The functional relationship between post  414  of assemblies  508  and receptacle  412  is also the same as described above with respect to spring device  400  and therefore will not be described in detail. 
   While considerable emphasis has been placed on the preferred embodiments of the invention illustrated and described herein, it will be appreciated that other embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.