Belleville spring assembly with elastic guides having low hysteresi

Macglashan, W. F., Jr.

Toth, L. R.

English

NASA Technical Reports Server

March 4, 1969 JAMES E. WEBB 3,430,942 
ADMINISTRATOR OF THE N A T I O N A L  A E R O N A U T I C S  
A N D  S P A C E  ADMINISTRATION 
BELLEVILLE SPRING ASSEMBLY WITH ELASTIC GUIDES 
F i l e d  May 17, 1967 Sheet I of 2 
2 5  
FIG. I 
https://ntrs.nasa.gov/search.jsp?R=19690018126 2020-03-16T18:44:55+00:00Z
FIG. 2 
INVENTORS 
LOUIS R. TOTH 
WILLIAM F. MacGLASHAN,JR. 
5 y  
ATT 0 R N  EY S 
3,430,942 United States Patent Office Patented Mar. 4, 1g6g 
1 2 
3.430.942 
BELLEVILLE SPkIN& ASSEMBLY WITH 
ELASTIC GUIDES 
James E. Webb. Administrator of the Nafional Aero- 
nautics and Space Administration, with respect to an in- 
vention by Louis R. Toah, Montrose, and William IF. 
MacGlashan, Jr., Pasadena, Calif‘. 
Filed May 17, 1967, Ser. No. 640,789 
U.S. CI. 267-1 5 Claims 
Int. CI. F16f 1/00,3/00 
ABSTRACT OF THE DISCLOSURE 
A plurality of flexible inner and outer retainers which 
maintain a plurality of Belleville springs, properly spaced 
from one another by means of grooves in the retainers 
within which the inner and outer peripheries of the springs 
are supported. The retainers are in turn supported so 
that under load when the inner and outer radii of the 
springs decrease and increase respectively, the retainers 
flex to accommodate such ‘changes in dimensions within 
the elastic limits of the retainers. 
A further object is to provide a new multiple Belleville 
spring assembly which exhibits very low hysteresis charac- 
teristics. 
Still a further object is the provision of a multiple 
Belleville spring assembly which has lower hysteresis 
and is less affected by adverse environments than the 
assembly presently known in the art. 
These and other objects of the invention are achieved 
by providing a multiple Belleville spring assembly which 
incorporates elastic or flexible inner and outer retainers 
or guides. rather than rieid retainers as is done in the 
5 
10 
prior art.’In the assembl; of the present invention, each 
of the guides defines a spine-like axial member from 
which two cantilever arms extend. The outer guides, 
15 together with the outer shell define an outer annular 
space, into which the flexible outer guides may flex 
radially outwardly, when the outer dimensions of the 
Belleville springs supported by the outer guides increase 
under load. Similarly, the inner guides together with a 
20 central pin define an inner annular space into which the 
inner guides may flex radially inwardly, when the inner 
dimensions of the Belleville spring tend to decrease under 
load in manners well appreciated by those familiar with 
the art. 
ORIGIN OF INVENTION 96 Due to the flexibility or elasticity of the inner and -” 
ne invention described here* was made in the per- 
to the provisions of Section 305 of the National Aero- 
nautics and Space Act Of ””’ 
Stat. 435; 42 USC 4257). 
outer guides and the free spaces inio which the guides 
structure, such as the outer shell and the central pin, 
the grooves in the various guides may be machined with 
Law 85-568 (72 30 relatively loose tolerances yet provide an assembly with 
low hysteresis. Also, since the changes in dimensions of 
the springs under load are compensated for by the flexibil- 
formance of work under a NASA contract and is subject may flex without friction between them and the support 
BACKGROUND OF THE INVENTION 
Description of the prior art ity of the various guides, the grooves need not be ma- 
chined to very accurate depths, without endangering bind- 
In U.S. Patent No. 3,127,157, entitled, “Multiple Belle- 35 ing between the springs and the various guides, as is 
ville spring Assembly,” an arrangement is disclosed in the case in the assembly of the prior art. 
which a plurality of Belleville spiings are retained, in The novel features that are considered characteristic 
Proper spaced relationships from one another, by means of this invention are set forth with particularity in the 
of a plurality of outer retainers and a Plurality of inner appended claims. The invention will best be understood 
retainers. The outer retainers are secured against radial 40 from the following description when read in connection 
separation by an outer shell, while a central is used with the accompanying drawings. 
to retain the inner retainers from contraction. The various 
retainers define annular grooves which are used to support 
the various rings about their outer and inner peripheries. 
quite useful, due to the rigidity of the various retainers 
and the close fitness between the retainers and the outer 
DESCRIPTION O F  THE PREFERRED shell and the central pin, close machining tolerances 
EMBODIMENT must be maintained when fabricating the various parts. For example, the external dimensions of the outer re- 
tainers must be carefully controlled to insure that they Reference is now made to FIGURES 1 and 2 which 
fit within the outer shell. Similarly, the inner retainers are an exploded view and a top elevational view respec- 
must be carefully machined so that the central pin fits tively, of the assembly of the present invention. Basically, 
therebetween. More importantly, the grooves in the inner the assembly includes an outer cylindrical shell 11, having 
and outer retainers, used to support the inner and outer 55 an inturned flange 12, at one end. A plurality of outer 
peripheries of the springs, must be accurately machined guides 13 are slidably fitted within shell 11. Preferably, 
with sufficient depth to provide sufficient space for the three outer guides are employed, each defining a 60” 
springs to expand into, when under load. Also, it has longitudinal segment of a hollow cylinder. 
been found that even when the various parts are properly Each outer guide 13 is provided with equally spaced 
machined, dirt, corrosion and adverse thermal environ- annular grooves 14 about the inner surface thereof. Pref- 
ments affect the overall performance of the assembly erably the grooves are limited to the longitudinal edges 
which greatly results in an increase of the hysteresis of the guides. Also, each guide 13 defines a spine-like 
thereof. member 15, which extends longitudinally along the center 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIGURE 1 is an isometric expanded view of the vari- 
FIGURE 2 is a top cross sectional view of the guides 
Though such an arrangement has been found to be 45 ous parts, forming the novel assembly; and 
when properly assembled. 
of the outer surface thereof. Each guide may be thought 
OBJECTS AND SUMMARY OF THE INVENTION a x  of as an elongated double cantilever, in which the mine- 
It is therefore a primary object of the present inven- ”., like member 15 forms the main structure with cantliever 
tion to provide a new improved multiple Belleville spring arms extending therefrom. When so regarding the guide, 
assembly. the grooves along the longitudinal edges thereof may be 
Another object is to provide a multiple Belleville spring thought of as being defined at the edges of the two can- 
assembly, which includes parts which need not be ma- ,,, tilever arms. At the end of each guide ,13 resting on 
chined with the high tolerances, dictated by the prior art flange 92, each member 15 is machined to form a pad 
arrangements. 15p, which extends radially from the inner surface of 
3,430,942 
3 4 
guide 13 to the outer surface of member 15. The func- nular spaces into which the arms of the inner guides and 
tion of these pads 15p is to support the guides 13 on outer guides respectively flex under load. That is, the 
flange 12 without frictionally engaging the arms of guides radial dimensions of the spaces are designed so that under 
13 on the flange so that the arms are free to flex as will maximum load, the arms of the guides may flex therein 
be described hereafter. without friction with either the pin 30 or the outer shell 11. 
Prior to being inserted in shell 11, grooves 14 receive Since the flexible or elastic guides accommodate changes 
the outer peripheries of Belleville springs 20 which, as in dimensions of the springs under load, the grooves de- 
is appreciated by those familiar with the art, are in the fined therein need not be machined with high tolerances, 
shape of cones, with central apertures. In FIGURE 1, since the depths of the grooves no longer accommodate 
although only one spring 20 is shown it should be ap- such dimensional changes. In practice, some preloading 
parent that as many as six springs may be supported by of the springs within the grooves of the various guides 
the assembly. When the guides 13 and springs 20 are may be desirable to remove all radial play without danger 
placed in shell 11, the spine-like members 15 are fric- of binding, Le. deformation of the springs or guides which 
tionally in contact with the shell -11. However, since generally increases the system's hysteresis. Also, since the 
the members 15 extend outwardly from guides 13, the 15 danger of binding is generally eliminated in the assembly 
guides and the shell define an annular outer space 22. of the present invention, the effect of dirt, corrosion, or  
As a result, a clearance is provided between the cantilever distortion due to adverse thermal environments on the 
arms of the guides 13 and shell 11. In the arrangement assembly's performance is eliminated or greatly mini- 
shown in FIGURES 1 and 2, it is assumed that the Belle- mized. 
ville springs curve outwardly, i.e. towards the top of the 20 As shown in FIGURE 1, the longitudinal surface of 
assembly. the guides 13 and 24 defines longitudinal slots 35 on both 
In addition, the assembly includes a plurality of inner the inner and outer surfaces thereof. These slots are ad- 
guides 24. Just as is the case with the outer guides 13, vantageous in increasing the flexibility of the guides un- 
it is preferable to use three inner guides 24, each &fin- der load, yet insure that the guides return to their un- 
ing a 60" segment of a hoIIow cylinder. Each inner guide 25 loaded shapes after the Belleville springs, supported in 
24 defines equally spaced annular grooves 25 on the ex- the grooves thereof, return to their normal geometric con- 
terior surface thereof, preferably limited to the longitu- figuration in the absence of the application of a force 
dinal edges. The inner peripheries of springs 20 are se- thereto. 
cured within these grooves. As a result, each spring is There has accordingly been shown and described herein 
supported at six points about the inner periphery thereof, 30 a novel multiple Belleville spring assembly, in which flex- 
as welI as at six points about the outer periphery. Like the ible or elastic double cantilever guides are employed. I t  
outer guides, each inner guide 24 has a spine-like mem- is appreciated that those familiar with the art may make 
ber 26 extending longitudinally along the center of the modifications and/or substitute equivalents in the arrange- 
inner surface thereof, so that each inner guide may be ments as shown without departing from the true spirit Of 
thought of as defining a double cantilever structure, with 35 the invention. 
the grooves 25 machined at the edges of the two arms. What is claimed is: 
An inner pin 30 is insertable between members 26 to 1. A multiple Belleville spring assembly comprising: 
prevent them from radial contraction under spring load- a plurality of annular, conical Belleville springs; 
ing. The pin is assumed to have a cap 31 of a diameter a plurality of elastic outer guides, each in the form of 
substantially equal to the inner diameter of springs 20. 40 a cylindrical longitudinal segment having a plurality 
Each member 26 is machined to form a pad 26p on which of annular inturned grooves for receiving portions of 
the cap 31 rests. the outer peripheries of said springs, each outer guide 
As is appreciated by those familiar with the art, when a further defining a spine-like member longitudinal ex- 
downward force, designated in FIGURE 1 by arrow F, is tending along the center of the exterior side thereof; 
applied to cap 31 of pin 30, the cap 31 applies the force 45 an outer shell in contact with the spine-like members 
to the pads 26p of guides 24, tending to place the springs of said outer guides securing said outer guides against 
20 under load. As a result, the springs tend to flat- radial separation, and defining an annular space be- 
ten out and thereby increase the outer diameters tween said outer means and the outer guides to en- 
or peripheries thereof, as well as decrease the inner able said outer guides to radially flex therein; 
diameters. In the assembly of the prior art, the changes 50 a Plurality of elastic inner guides, each in the form of 
in outer and inner dimensions of the springs are ac- a cylindrical longitudinal segment, having a plurality 
commodated for by the depths of the grooves in the of annular grooves on the external surface thereof 
inner and outer guides. However, in the novel assembly and a spine-like member Iongitudinally extending 
of the present invention, the changes in the dimensions along the center of the interior side thereof, portions 
of the springs under load are accommodated by the flexi- 55 of the inner Peripheries of said springs being engaged 
bility or elasticity of the various guides. Under load, as in the annular grooves of said elastic inner guides; 
the springs 20 tend to flatten out and thereby resulting and 
in an increase in the outer peripheries thereof, the can- inner removable means in contact with the spine-like 
tilever arms of guides 13 tend to flex, radially outwardly, members of said inner guides to secure said inner 
into spaces 22. Similarly, when the springs are under load, 60 guides against radial contraction, said inner remov- 
and the inner peripheries thereof tend to decrease, i.e. the able means and the inner sides of said inner guides 
inner radii of the springs decrease, the arms of guides 24 defining an inner annular space to enable said inner 
tend to flex radially inwardly into free spaces 32, defined guides to radially flex therein. 
by the pin 30 and the inner surfaces of guides 24. con- 2. The assembly as recited in claim 1 wherein each of 
sequently, the changes in dimensions of the springs under 65 said outer guides comprises a double cantilever structure, 
load are accommodated by the fieXing of the inner and with the spine-like member having two arms extended 
outer guides. therefrom, said annular inturned grooves being defined at 
The arms of the guides are designed to flex within the the ends Of said arms. 
elastic limit of the metal from which the guides are ma- 3. The assembly as recited in claim 2 wherein each of 
chined. Thus, after the removal of the force to pin 30, 70 said outer guides defines a plurality of longitudinal slots 
when the BeIIeviIle springs return to their initial shape in said z~mS between the spine-like member and the 
or state, the various flexible guides similarly return to grooves defined therein. 
their unloaded state. As a result, a spring assembly of 4. The assembly as recited in claim 1 wherein each of 
very low hysteresis is provided. The very low hysteresis said inner guides comprises a double cantilever structure, 
is also due to the dimensions of the inner and outer an- 75 with the spine-like member thereof defining a central Ion- 
3,430,942 
5 
gitudinal member having two arms extended therefrom, 
said annular grooves being defined at the ends of said 
arms. 
6 
References Cited 
UNITED STATES PATENTS 
5. The assembly as recited in claim 4 wherein each of 2,936,805 5/1960 Rice _ _ _ _ _ - _ _ _ _ _ _ _ _ _  267-1 X 
the inner guides defines a plurality of longitudinal slots 3,127,157 3/1964 Webb _______-________ 267-1 
in said arms between the spine-like member and the 
grooves defined therein, DRAYTON E. HOFFMAN, Primary Examiner. 


Belleville spring assembly with elastic guides

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