Abstract:
Disc springs that are resistant to premature failure caused by friction wear, disc spring assemblies and disc spring stacks comprising said disc springs, and methods of making and using said assemblies and stacks are disclosed.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to disc springs and disc spring stacks that are resistant to friction wear. 
       BACKGROUND OF THE INVENTION 
       [0002]    Disc springs, sometimes referred to as Belleville washers or Belleville springs, are conical shaped washers which are designed to be loaded in an axial direction. Under high loads disc springs produce small deflections, as compared with other types of springs such as helical or coil springs. 
         [0003]    Variable spring characteristics can be achieved by stacking a plurality of disc springs. A problem with stacking a plurality of disc springs, particularly, when stacking in parallel, is the need to maintain the plurality of disc springs in the stack when a force is applied axially on the stack. Furthermore, when such a force is applied axially to a parallel spring stack, the adjacent surfaces of the disc springs may rub against each other, causing friction wear. This friction wear is often the cause of premature failure of disc spring configurations. 
         [0004]    There is a need for improved disc springs and disc spring stacks and configurations. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides, in a first aspect, a generally conically shaped disc spring which includes a first radial inner portion defining a center hole therein and a first radial outer portion. The first radial inner portion of the disc spring has a downwardly-depending portion and the first radial outer portion of the disc spring has an upwardly-extending portion. The disc spring has a first intermediate portion which deflects under axial load between the first radial outer portion and the first radial inner portion. Further, the disc spring is configured to be stacked in parallel with another one or more of the same disc springs. When stacked, the intermediate portions of the stacked disc springs deflect under axial load while maintaining a space between the adjacent intermediate portions of the stacked 
         [0006]    The present invention provides, in a second aspect, a disc spring stack which includes a first assembly. The first assembly includes generally conically-shaped disc springs that are stacked in parallel such that the conical adjacent surfaces of successive disc springs are spaced apart. The first assembly includes a first generally conically-shaped disc spring that has a first radial inner portion that defines a center hole therein, and a first radial outer portion. The first radial inner portion has a downwardly-depending portion and the first radial outer portion has an upwardly-extending portion. The first disc spring has a first intermediate portion which deflects under axial load. The first assembly also includes a second generally conically-shaped disc spring that has a second radial inner portion that defines a center hole therein, and a second radial outer portion. The second radial inner portion has a downwardly-depending portion, and the second radial outer portion has an upwardly-extending portion. The second disc spring has a second intermediate portion which deflects under axial load. In the first assembly, the second disc spring is stacked in parallel on the first disc spring such that the upwardly-extending portion of the first radial outer portion of the first disc spring is received on the second radial outer portion of the second disc spring. Further, when stacked, the downwardly-depending portion of the second radial inner portion of the second disc spring is received on the first radial inner portion of the first disc spring. As a result, the first intermediate portion of the first disc spring and the second intermediate portion of the second disc spring deflect under axial load while maintaining a space therebetween so as to avoid friction between the surfaces and resulting hysteresis that can be avoided by separating the parallel surfaces. 
         [0007]    The present invention provides, in a third aspect, a disc spring stack which includes a first assembly, as described above, and a second assembly. The second assembly includes a third generally conically-shaped disc spring that has a first radial inner portion that defines a center hole therein, and a first radial outer portion. The first radial inner portion has an upwardly-extending portion and the first radial outer portion has a downwardly-depending portion. The third disc spring has a first intermediate portion which deflects under axial load. The second assembly also includes a fourth generally conically-shaped disc spring that has a second radial inner portion that defines a center hole therein, and a second radial outer portion. The second radial inner portion has an upwardly-extending portion, and the second radial outer portion has a downwardly-depending portion. The fourth disc spring has a second intermediate portion which deflects under axial load. In the second assembly, the fourth disc spring is stacked in parallel on the third disc spring. Therefore, the upwardly-extending portion of the first radial inner portion of the third disc spring is received on the second radial inner portion of the fourth disc spring and the downwardly-depending portion of the second radial outer portion of the fourth disc spring is received on the first radial outer portion of the third disc spring so that the first intermediate portion of the third disc spring and the second intermediate portion of the fourth disc spring deflect under axial load while maintaining a space therebetween so as to avoid friction wear. 
         [0008]    The present invention provides, in a fourth aspect, a disc spring stack which includes a first assembly and a second assembly, wherein said second assembly is connected to said first assembly such that the downwardly-depending portions of the third disc spring on the second assembly extend downward into the upwardly-extending portions of the second disc spring on the first assembly. 
         [0009]    The present invention provides, in a fifth aspect, a disc spring stack which includes a first assembly and a second assembly, wherein a spacer is disposed at the point of connection between the first and second assemblies. 
         [0010]    The present invention provides, in a sixth aspect, a disc spring stack which includes a first assembly and a second assembly, wherein the second assembly is connected to the first assembly such that the downwardly-depending portions of the third disc spring on the second assembly extend downward into a spacer, which the upwardly-extending portions of the second disc spring on the first assembly extend upward into. 
         [0011]    The present invention provides, in a seventh aspect, a method of making a disc spring stack that includes a first assembly of generally conically-shaped disc springs that are stacked in parallel such that the conical adjacent surfaces of successive disc springs are spaced apart. This method includes obtaining a first generally conically-shaped disc spring that has a first radial inner portion defining a center hole therein and a first radial outer portion. The first radial inner portion has a downwardly-depending portion and the first radial outer portion has an upwardly-extending portion. The first disc spring has a first intermediate portion which deflects under axial load. Next, a second generally conically-shaped disc spring is obtained, which has a second radial inner portion defining a center hole therein and a second radial outer portion. The second radial inner portion has a downwardly-depending portion, and the second radial outer portion has an upwardly-extending portion. The second disc spring has a second intermediate portion which deflects under axial load. Next, the second disc spring is stacked in parallel on the first disc spring, such that the upwardly-extending portion of the first radial outer portion of the first disc spring is received on the second radial outer portion of the second disc spring. As a result of this method, the downwardly-depending portion of the second radial inner portion of the second disc spring is received on the first radial inner portion of the first disc spring, so as to allow the first intermediate portion of the first disc spring and the second intermediate portion of the second disc spring to deflect under axial load while maintaining a space therebetween so as to avoid friction wear. 
         [0012]    The present invention provides, in an eighth aspect, a method of making a disc spring stack that includes a first and second assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, may be understood by reference to the following detailed descriptions of the following embodiments and the accompanying drawings in which: 
           [0014]      FIG. 1  is a cross-sectional view of a disc spring stack that has a first assembly stacked in series with a second assembly, each assembly having three disc springs stacked in parallel; 
           [0015]      FIG. 1A , an exploded view of a section shown in  FIG. 1 , is a cross-sectional view of three disc springs that are stacked in parallel, and shows that the disc springs are configured such that the surfaces of adjacent springs will not rub against one another under axial load. 
           [0016]      FIG. 2  is a cross-sectional view of a disc spring stack that has a first, a second, and a third assembly, which are stacked in series with one another, each assembly having three disc springs stacked in parallel, with spacers disposed at the points of contact between the assemblies; 
           [0017]      FIG. 2A , an exploded view of a section shown in  FIG. 2 , is a cross-sectional view of two parallel-stacked disc springs that comprise part of a first assembly, and one disc spring from a second assembly that is stacked in series adjacent to the first assembly, as well as a spacer that is disposed at the point of contact between the assemblies; 
           [0018]      FIG. 3  is a cross-sectional view of a disc spring stack that has a first, a second, and a third assembly, which are stacked in series with one another, each assembly having three disc springs stacked in parallel, with spacers disposed between the points of contact of the assemblies; 
           [0019]      FIG. 3A , an exploded view of a section shown in  FIG. 3 , is a cross-sectional view of two parallel-stacked disc springs that comprise part of a first assembly, and one disc spring from a second assembly that is stacked in series adjacent to the first assembly, as well as a spacer that is disposed between the points of contact of the assemblies. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The disc springs and disc spring stacks of the present invention include a plurality of generally conically-shaped disc springs in which adjacent disc springs fit together and are held together in axial alignment. The disc spring stacks generally comprise a ring-shaped configuration and include an outer peripheral edge, which may be positioned within a cylindrically-shaped cavity or tube (not shown), and an inner edge, which may be positioned about a shaft or aligning rod (not shown). The disc springs may optionally be interlocking, which feature would allow the assemblies to be used without any confining cylinder or shaft in order to hold the disc springs in alignment, particularly under an axial load applied to the disc spring stack. 
         [0021]      FIG. 1  illustrates a disc spring stack  100 , in accordance with the present invention, having a first assembly  200 , and a second assembly  300 , with said assemblies stacked in series with one another. In general, stacking assemblies of disk springs in series with one another results in increased deflection, proportional to the number of assemblies in a stack. 
         [0022]    First assembly  200  includes a first disc spring  220 , a second disc spring  240 , and a third disc spring  260 . First disc spring  220  has a first radial inner portion  222 , a first radial outer portion  226 , and a first intermediate portion  225  between the first radial inner portion  222  and the first radial outer portion  226 , which deflects under axial load. First radial inner portion  222  defines a first central opening therethrough and includes a downwardly-depending portion  224 . First radial outer portion  226  includes an upwardly-extending portion  228 . “Upwardly” and “downwardly” are used herein to refer to directions when the disc springs described herein are stacked atop one another. Specifically, “upwardly” refers to a direction generally toward a first end of the stack of disc springs and “downwardly” refers to a direction generally toward a second end of the stack. 
         [0023]    First disc spring  220  is stacked in parallel with disc springs  240  and  260 , which share the same orientation. Generally, stacking disc springs in parallel increases the load proportional to the number of springs in parallel with one another. Second disc spring  240  has a second radial inner portion  242 , a second radial outer portion  246 , and a second intermediate portion  245  between the second radial inner portion  242  and the second radial outer portion  246 , which deflects under axial load. Second radial inner portion  242  defines a second central opening therethrough and includes a downwardly-depending portion  244 . Second radial outer portion  246  includes an upwardly-extending portion  248 . Third disc spring  260  has a third radial inner portion  262 , a third radial outer portion  266 , and a third intermediate portion  265  between the third radial inner portion  262  and the third radial outer portion  266 , which deflects under axial load. Third radial inner portion  262  defines a third central opening therethrough and includes a downwardly-depending portion  264 . Third radial outer portion  266  includes an upwardly-extending portion  268 . 
         [0024]    As illustrated in  FIG. 1 , downwardly-depending portion  244  of second radial inner portion  242  of disc spring  240  is receivable within first radial inner portion  222  of disc spring  220  when disc spring  240  is stacked in parallel on disc spring  220 . In addition, upwardly-extending portion  228  of first radial outer portion  226  of disc spring  220  is receivable in second radial outer portion  246  of disc spring  240 . When disc springs are stacked on one another, for example, when disc spring  240  is stacked on disc spring  220 , the surfaces of the adjacent disc springs may be aligned with one another. It will also be appreciated, however, that the first opening and the second opening may comprise different configurations or sizes and need not be alignable. 
         [0025]      FIG. 1  shows that downwardly-depending portion  264  of third radial inner portion  262  of disc spring  260  is receivable within second radial inner portion  242  of disc spring  240  when disc spring  260  is stacked in parallel on disc spring  240 . In addition, upwardly-extending portion  248  of second radial outer portion  246  of disc spring  240  is receivable in third radial outer portion  266  of disc spring  260 . 
         [0026]    Second assembly  300  of disc spring stack  100  includes a fourth disc spring  320 , a fifth disc spring  340 , and a sixth disc spring  360 . Disc spring  320  has a first radial inner portion  322 , a first radial outer portion  326 , and a first intermediate portion  325  between first radial inner portion  322  and first radial outer portion  326 , which deflects under axial load. First radial inner portion  322  defines a first central opening therethrough and includes an upwardly-extending portion  324 . First radial outer portion  326  includes a downwardly-extending portion  328 . 
         [0027]      FIG. 1  shows that fourth disc spring  320  is stacked in parallel with fifth disc spring  340  and sixth disc spring  360 . Fifth disc spring  340  has a second radial inner portion  342 , a second radial outer portion  346 , and a second intermediate portion  345  between second radial inner portion  342  and second radial outer portion  346 , which deflects under axial load. Second radial inner portion  342  defines a second central opening therethrough and includes an upwardly-extending portion  344 . Second radial outer portion  346  includes a downwardly-depending portion  348 . Sixth disc spring  360  has a third radial inner portion  362 , a third radial outer portion  366 , and a third intermediate portion  365  between third radial inner portion  362  and third radial outer portion  366 , which deflects under axial load. Third radial inner portion  362  defines a third central opening therethrough and includes an upwardly-extending portion  364 . Third radial outer portion  366  includes a downwardly-depending portion  368 . 
         [0028]    Downwardly-depending portion  348  of second radial outer portion  346  of disc spring  340  is receivable within first radial outer portion  326  of disc spring  320  when disc spring  340  is stacked in parallel on disc spring  320 . In addition, upwardly-extending portion  324  of first radial inner portion  322  of disc spring  320  is receivable in second radial inner portion  342  of disc spring  340 . Similarly, downwardly-depending portion  368  of third radial outer portion  366  of disc spring  360  is receivable within second radial outer portion  346  of disc spring  340  when disc spring  360  is stacked in parallel on disc spring  340 . In addition, upwardly-extending portion  344  of second radial inner portion  342  of disc spring  340  is receivable in third radial inner portion  362  of disc spring  360 . 
         [0029]    It is an aspect of the instant invention that assemblies of disc springs stacked in parallel may be stacked in series with one another. This aspect is illustrated in  FIG. 1 , where assembly  200  is stacked in series with assembly  300 . There, downwardly-depending portion  328  of first radial outer portion  326  of disc spring  320  rests on upwardly-extending portion  268  of third radial outer portion  266  of disc spring  260 , so that the two assemblies are stacked in series with one another. Similarly, assemblies of disc springs may be stacked in series with one another by contact at the radial inner portions of the disc springs, as shown in  FIG. 2 . It will be appreciated that additional assemblies may be stacked in series with assemblies  200  and  300 . 
         [0030]    From the present description, it will be appreciated that a pair of first and second disc spring assemblies may be suitably used and stacked, for example, with their radial inner portions engaging or with their radial outer portions engaging. 
         [0031]    It is a further aspect of the instant invention that the disc springs are configured such that when a disc spring is stacked in parallel with at least one other disc spring, the conical adjacent surfaces of successive disc springs are spaced apart so that they will not rub against each other. More specifically, it is an aspect of the instant invention that when the disc springs are stacked in parallel, intermediate portions of adjacent disc springs have a gap or space therebetween. Thus, the intermediate portion of a disc spring will not touch the intermediate portion of an adjacent disc spring in the parallel stack, even when there is a deflection under axial load. Furthermore, the intermediate portion of a disc spring preferably will not touch the radial inner portion or the radial outer portion of adjacent disc springs with which it is stacked in parallel, or the upwardly-extending or downwardly-depending portions thereof, even upon deflecting a specified amount under axial load. This aspect of the present invention represents a significant advantage over the prior art insofar as it prevents premature failure of disc springs due to friction wear. 
         [0032]      FIG. 1A , which is an exploded view of a section shown in  FIG. 1 , illustrates this aspect of the invention. Because of the configuration of the disc springs, the adjacent surfaces of the intermediate portions  325 ,  345 , and  365  of disc springs  320 ,  340 , and  360  are separated by a space or gap therebetween and do not rub against one another when they deflect under an axial force. As shown in  FIG. 1A , even upon deflecting under axial load, second intermediate portion  345  of disc spring  340  will not rub against first intermediate portion  325  of first of disc spring  320 . Likewise, second intermediate portion  345  will not rub against upwardly-extending portion  324  of first radial inner portion  322  of disc spring  320  when it deflects, at least for a specified amount. Similarly, when third intermediate portion  365  deflects, it will not touch second intermediate portion  345 , or upwardly-extending portion  344  of second radial inner portion  342  of disc spring  340 , at least for a specified amount. 
         [0033]      FIG. 2  illustrates a disc spring stack  400  that has a first assembly  500 , a second assembly  600 , and a third assembly  700 , which are stacked in series with one another. First assembly  500  includes a first disc spring  520 , a second disc spring  540 , and a third disc spring  560 , the three of which are stacked in parallel with one another. 
         [0034]    First disc spring  520  has a first radial inner portion  522 , a first radial outer portion  526 , and a first intermediate portion  525  between first radial inner portion  522  and first radial outer portion  526 , which deflects under axial load. First radial inner portion  522  defines a first central opening therethrough and includes a downwardly-depending portion  524 . First radial outer portion  526  includes an upwardly-extending portion  528 . Second disc spring  540  has a second radial inner portion  542 , a second radial outer portion  546 , and a second intermediate portion  545  between second radial inner portion  542  and second radial outer portion  546 , which deflects under axial load. Second radial inner portion  542  defines a second central opening therethrough and includes a downwardly-depending portion  544 . Second radial outer portion  546  includes an upwardly-extending portion  548 . Third disc spring  560  has a third radial inner portion  562 , a third radial outer portion  566 , and a third intermediate portion  565  between third radial inner portion  562  and third radial outer portion  566 , which deflects under axial load. Third radial inner portion  562  defines a third central opening therethrough and includes a downwardly-depending portion  564 . Third radial outer portion  566  includes an upwardly-extending portion  568 . 
         [0035]    Second assembly  600  includes a fourth disc spring  620 , a fifth disc spring  640 , and a sixth disc spring  660 , the three of which are stacked in parallel with one another. Fourth disc spring  620  has a first radial inner portion  622 , a first radial outer portion  626 , and a first intermediate portion  625  between first radial inner portion  622  and first radial outer portion  626 , which deflects under axial load. First radial inner portion  622  defines a first central opening therethrough and includes an upwardly-extending portion  624 . First radial outer portion  626  includes a downwardly-depending portion  628 . Fifth disc spring  640  has a second radial inner portion  642 , a second radial outer portion  646 , and a second intermediate portion  645  between second radial inner portion  642  and second radial outer portion  646 , which deflects under axial load. Second radial inner portion  642  defines a second central opening therethrough and includes an upwardly-extending portion  644 . Second radial outer portion  646  includes a downwardly-depending portion  648 . Sixth disc spring  660  has a third radial inner portion  662 , a third radial outer portion  666 , and a third intermediate portion  665  between third radial inner portion  662  and third radial outer portion  666 , which deflects under axial load. Third radial inner portion  662  defines a third central opening therethrough and includes an upwardly-extending portion  664 . Third radial outer portion  666  includes a downwardly-depending portion  668 . 
         [0036]    Third assembly  700  includes a seventh disc spring  720 , an eighth disc spring  740 , and a ninth disc spring  760 , the three of which are stacked in parallel with one another. Seventh disc spring  720  has a first radial inner portion  722 , a first radial outer portion  726 , and a first intermediate portion  725  between first radial inner portion  722  and first radial outer portion  726 , which deflects under axial load. First radial inner portion  722  defines a first central opening therethrough and includes a downwardly-depending portion  724 . First radial outer portion  726  includes an upwardly-extending portion  728 . Eighth disc spring  740  has a second radial inner portion  742 , a second radial outer portion  746 , and a second intermediate portion  745  between second radial inner portion  742  and second radial outer portion  746 , which deflects under axial load. Second radial inner portion  742  defines a second central opening therethrough and includes a downwardly-depending portion  744 . Second radial outer portion  746  includes an upwardly-extending portion  748 . Ninth disc spring  760  has a third radial inner portion  762 , a third radial outer portion  766 , and a third intermediate portion  765  between third radial inner portion  762  and third radial outer portion  766 , which deflects under axial load. Third radial inner portion  762  defines a third central opening therethrough and includes a downwardly-depending portion  764 . Third radial outer portion  766  includes an upwardly-extending portion  768 . 
         [0037]    As shown in  FIG. 2 , assemblies  500 ,  600 , and  700  are stacked in series with one another. Downwardly-depending portion  628  of first radial outer portion  626  of disc spring  620  makes contact with upwardly-extending portion  568  of third radial outer portion  566  of disc spring  560  when assembly  600  is stacked in series on assembly  500 . Furthermore, downwardly-depending portion  724  of first radial inner portion  722  of disc spring  720  contacts with upwardly-extending portion  664  of third radial inner portion  662  when assembly  700  is stacked in series on assembly  600 . 
         [0038]    As illustrated in  FIG. 2A , which is an exploded view of a section shown in  FIG. 2 , the disc springs in assemblies  500 ,  600 , and  700  have a slightly different configuration than the disc springs in assemblies  200  and  300  from  FIG. 1 . Despite this difference, the disc springs still share the same aspect whereby intermediate portions of parallel-stacked disc springs have a space or gap therebetween and do not touch the intermediate portions, the inner or outer portions, or the upwardly-extending or downwardly-depending portions thereof, of adjacent disc springs. For example,  FIG. 2A  shows that when it deflects, second intermediate portion  645  of disc spring  640  will not rub against first intermediate portion  625  or, for at least a specified amount of deflection, first radial outer portion  626  of disc spring  620 . 
         [0039]    In some embodiments the present invention includes spacers disposed between radial inner and/or radial outer portions where disc spring assemblies are connected in series. This aspect of the invention permits additional rotational deflection of the component springs as the stacks are compressed, and is illustrated in  FIG. 2  and  FIG. 3 .  FIG. 2  illustrates spacers disposed at the point of connection between assembly  500  and assembly  600 , as well as at the point of connection between assembly  600  and assembly  700 . 
         [0040]      FIG. 3  illustrates a disc spring stack  800  that has a first assembly  900 , a second assembly  1000 , and a third assembly  1100 , which are stacked in series with one another, with each assembly including three disc springs that are stacked in parallel with one another. 
         [0041]    In  FIG. 3 , first assembly  900  includes a first disc spring  920 , a second disc spring  940 , and a third disc spring  960 , the three of which are stacked in parallel with one another. First disc spring  920  has a first radial inner portion  922 , a first radial outer portion  926 , and a first intermediate portion  925  between first radial inner portion  922  and first radial outer portion  926 , which deflects under axial load. First radial inner portion  922  defines a first central opening therethrough and includes a downwardly-depending portion  924 . First radial outer portion  926  includes an upwardly-extending portion  928 . Second disc spring  940  has a second radial inner portion  942 , a second radial outer portion  946 , and a second intermediate portion  945  between second radial inner portion  942  and second radial outer portion  946 , which deflects under axial load. Second radial inner portion  942  defines a second central opening therethrough and includes a downwardly-depending portion  944 . Second radial outer portion  946  includes an upwardly-extending portion  948 . Third disc spring  960  has a third radial inner portion  962 , a third radial outer portion  966 , and a third intermediate portion  965  between third radial inner portion  962  and third radial outer portion  966 , which deflects under axial load. Third radial inner portion  962  defines a third central opening therethrough and includes a downwardly-depending portion  964 . Third radial outer portion  966  includes an upwardly-extending portion  968 . 
         [0042]    Second assembly  1000  includes a fourth disc spring  1020 , a fifth disc spring  1040 , and a sixth disc spring  1060 , the three of which are stacked in parallel with one another. Fourth disc spring  1020  has a first radial inner portion  1022 , a first radial outer portion  1026 , and a first intermediate portion  1025  between first radial inner portion  1022  and first radial outer portion  1026 , which deflects under axial load. First radial inner portion  1022  defines a first central opening therethrough and includes an upwardly-extending portion  1024 . First radial outer portion  1026  includes a downwardly-depending portion  1028 . Fifth disc spring  1040  has a second radial inner portion  1042 , a second radial outer portion  1046 , and a second intermediate portion  1045  between second radial inner portion  1042  and second radial outer portion  1046 , which deflects under axial load. Second radial inner portion  1042  defines a second central opening therethrough and includes an upwardly-extending portion  1044 . Second radial outer portion  1046  includes a downwardly-depending portion  1048 . Sixth disc spring  1060  has a third radial inner portion  1062 , a third radial outer portion  1066 , and a third intermediate portion  1065  between third radial inner portion  1062  and third radial outer portion  1066 , which deflects under axial load. Third radial inner portion  1062  defines a third central opening therethrough and includes an upwardly-extending portion  1064 . Third radial outer portion  1066  includes a downwardly-depending portion  1068 . 
         [0043]    Third assembly  1100  includes a seventh disc spring  1120 , an eighth disc spring  1140 , and a ninth disc spring  1160 , the three of which are stacked in parallel with one another. Seventh disc spring  1120  has a first radial inner portion  1122 , a first radial outer portion  1126 , and a first intermediate portion  1125  between first radial inner portion  1122  and first radial outer portion  1126 , which deflects under axial load. First radial inner portion  1122  defines a first central opening therethrough and includes a downwardly-depending portion  1124 . First radial outer portion  1126  includes an upwardly-extending portion  1128 . Eighth disc spring  1140  has a second radial inner portion  1142 , a second radial outer portion  1146 , and a second intermediate portion  1145  between second radial inner portion  1142  and second radial outer portion  1146 , which deflects under axial load. Second radial inner portion  1142  defines a second central opening therethrough and includes a downwardly-depending portion  1144 . Second radial outer portion  1146  includes an upwardly-extending portion  1148 . Ninth disc spring  1160  has a third radial inner portion  1162 , a third radial outer portion  1166 , and a third intermediate portion  1165  between third radial inner portion  1162  and third radial outer portion  1166 , which deflects under axial load. Third radial inner portion  1162  defines a third central opening therethrough and includes a downwardly-depending portion  1164 . Third radial outer portion  1166  includes an upwardly-extending portion  1168 . 
         [0044]      FIG. 3  illustrates that in some embodiments, the present invention may use spacers that are disposed between the points of connection of assemblies that are stacked in series. For example, as shown in  FIG. 3 , and in  FIG. 3A , which is an exploded view of a section shown in  FIG. 3 , downwardly-depending portion  1124  of first radial inner portion  1122  of seventh disc spring  1120  depends downward into a spacer. Upwardly-extending portion  1064  of third radial inner portion  1062  of sixth disc spring  1060  extends upward into the same spacer, which connects the two assemblies. 
         [0045]    As illustrated in  FIG. 3A , the disc springs in spring stack  800  have a slightly different configuration than the disc springs in spring stacks  100  and  400 . However, as in disc spring stacks  100  and  400 , the disc springs in stack  800  still share the same aspect whereby intermediate portions of parallel-stacked disc springs have a gap or space therebetween and do not touch the intermediate portions, the inner or outer portions, or the upwardly-extending or downwardly-depending portions thereof, of adjacent disc springs. For example,  FIG. 3A  shows that because of its shape, when eighth disc spring  1140  deflects, its second intermediate portion  1145  will not rub against first intermediate portion  1125  or, for at least a specified amount of deflections, the first radial inner portion  1122  of disc spring  1120 . 
         [0046]    The above-described disc springs may be formed from heat treatable spring steel or tool steel alloys such as AISI D-2 or AISI H-11, high temperature alloys such as Inconel 625, or heat treatable precipitation hardening alloys such as Inconel 718, for example. The spacers may be formed from ductile stainless steel such as 304 stainless steel or Inconel 625, for example. The disc springs described above may be formed by machining. Alternatively, the disc springs described above may be formed by stamping, as will be understood by those skilled in the art. 
         [0047]    The disc springs may be pre-coated with a sealant before assembly or may be coated after assembly of the disc spring assemblies and stacks. The coatings may include a soft compliant material such as butyl rubber, Teflon, or a soft metal such as gold or silver. 
         [0048]    The above-described disc springs, disc spring assemblies, and disc spring stacks may be utilized as sealing elements for various static (e.g., non-rotating) applications or dynamic (e.g., rotating) applications which typically require that the sealing elements have significant flexibility. In addition, the uppermost and lowermost disc springs of the disc spring stacks may be formed with a sharpened edge at their radial outer portions so that a seal might be formed by imbedding the sharpened ends of the disc spring into the structure (not shown) to be sealed. 
         [0049]    The disc springs and spacers in accordance with the present invention may be formed in any shape or size to allow resiliency, adjustability, and compression in any desired direction, when received in any number of restricted spaces, as will be understood by those skilled in the art. For example, it would be evident from the above description to one skilled in the art that the upwardly-extending portions of the disc springs described above could be downwardly-depending and the downwardly-depending portions of the disc springs described above could be upwardly-extending. Also, the spacers described above may be optionally adjustable, and may be adapted to receive only one disc spring while the free ends of the spacer may be adapted to engage a surface or object, as will be understood by those skilled in the art. 
         [0050]    While the invention has been described in detail herein in accordance with certain embodiments thereof, many modifications and changes therein may be effected by those skilled in the art. Accordingly, it is intended by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.