US2319172A - Spacing device for frictionally opposed bodies - Google Patents

Description

May l1, 1943 A .L w. WATSON ETAL 2,319,172

SPACING DEVICE FOR FRICTIONALLY OVPPOSED BODIES Filed June 11, 1940 SPACING DEVICE FGR'FRICTIONALLYf i OPPOSED BODIES l John Warren Watson, Wayne, Pa., and Kenneth 'WJ Hildenbrand, Monroe, Mich., assignors to John Warren Watson Company, Philadelphia, Pax, a corporation oflennsylvania Application June 11, 1940, serial No, 33.9;954

4 claims. A(or zer- 47) This invention relates to a device forspacing two bodies which'a're-'subjected to relative movements and pressure and, in 'particular-,to a de vice for spacing the leaves of' a multipleleaf spring, inorder to -provide smooth and silent ac tion to relative movements of -the said bodies-or A particular object of our invention' is to provide a .positive spacing of the-spring leaves at their tip ends, f orit'is at the tip ends of each leaf that the greatest movements and highestv pI'eSSuleS Occur;

our invention, it will be noted that each'of the devices has a localized area4 of increased thick- V "ness to provide a'firm projection for interlocking, anchoring engagement withone of thespring leaves. In these preferred examples, the projection provided byJthe Aincreased thickness is of a 4character to engage vin a recess formed adjacent the tip end of the leaf. Referring' to'Fig.' 2, the spacing portion I of-the device `andthe projecting portion lare-formed-- t integrally as, for example, if made of a textile A further particular object'of the invention is to provide a positive anchoring means to maintain thedevice, unfailingly, in its proper position with relation to the leaf end.

A further and also very particularobject of l the invention is t provide a spacing device of material which is suiciently yieldable to permit it to readily conform with any unevenness of surface encountered in its contactwith the leaves which'it is spacing. This conformability and Vresulting snug and complete .contact between the clevice and an adjacent leaf produces a, firm seal against the entry'thereb'etw'een o f abrasives and other objectionable matter. l AA further particular object ofthe invention is to construct the spacing device of material possessing a substantial balance between its static and dynamic coeicientsof friction. Such balance is necessary in order to avoid to a satisfactory degree the spasmodic actions, vibrations "and noises which would otherwise occur duringrelatlvemovements between thespacing device and the' leaf surface against which 'it' coacts.

vA further object of the invention is to provide a device constructed of such materialas will not elements with which it is likely to come in con- Referring to the drawing:

Figure .-1 is an elevational, fragmentary View cfa-leaf spring, showing a portion of three leaves and two of the spacing'de'vice's in position therebetweem' Fig. 2 is a fragmentary longitudinal sectional view illustrating one means for positive anchorv4forming in a suitable die.

fabric, during the vweaving `operation.

Referring to' the construction ofthe spacing f device shown in Figure 3, member I'is the spacer proper, and-member] is a projecting lugwhichl may beconstructed of the same material as Athe spacer proper,v or may be constructed'of any other material of suitable strength and enduring: 'quality. Thespacer properand the lug' are firmly attachedA together by means of a rivet' 3, or by 'staplingt or by any other positive means;

Referring to Figure 4J Athe projecting portion' 2 is'made integral with the spacer portion I, by

With this pconstruction, it Vyis preferred, in order to more positively maintain and preserve 4the shape of the project- `ing portion 2,' to ,include button member 4, which is .securely held` in place by means of a rivet 3, or

by stapling, or byo'ther 'suitablefmeans Referring to Figure 5; the spacing element I is "heldin positive relation with respect to theleaf.

` -endby means of one'or more rivets 5, or' by some such other-suitably positive device, to prevent its be detrimentally affected by water, oil or other f age ofthe device in accordancefwithour invention;

Fig. 3`is a transverse sectional elevation of two leaves and a' spacing device showing a preferred form of construction for accomplishing the. neces sary positive anchorage of the device with relation to the end of a spring leaf;

' Fig. 4 shows an 'alternate method of construction forl providing the necessary anchoragel means; and

Fig. 5 shows a still further modification for providinga positive anchorage.

lReferring to the above illustrated examples of displacement from between the leaves.

that of the rivet area.

The'holes or recesses shown' in'th'e spring leaves, aswell as the cooperating lug or projecting .portions 2 shown in-Figures 2, 3 and 4, may be of round section; but it is preferred to'rnake .themof oval orother irregular section', in order to keep the spacers'froxnA turning and to" thus maintain their proper alignment with` relation tothe spring leaves. 'This maintenance of. proper alignment is important, lif Vthe spacerportion I is to be made square `or rectangulargfandjsuch shape for the spacer portion' is preferred over a spacer of round shape as'greater area,"and hence greater life, is provided at no eXtra cost'. 5o

projecting portion could be made to hold the A' round hole in the spring'leaf and a round I device from turning by making the diameter of the projection somewhat larger than the hole 'diameter and forcing it into /placet To insure maintenance of alignment ,of square or rectangular spacing portion in the example of the device shown in Fig. 5, a snug tting rivet may prove s umcient, but it is preferred to use more than one projecting rivet.

In the case of a multiple leaf spring, practi- In 'this' device, th'e area of `increased thickness is only the load along to the next tip and so on along .the une theme51: remote.np. rt isfor this reason that oilfor"`grease cannot be maintained jected in service and inthe handling of the spring.

That the spacers be made of yieldable material is of utmost importance in order that the imposed load may readily pad. them down to conform with any irregularities of the leaf surface and thus establish a snug-fitting and definite seal against the entry of foreign abrasives.

As to the coeiilcient of friction of the material oi which the spacers are made, quite a bit will depend upon the particular duty which the spring or other mechanism is to perform. In certain duties a very low coefilcient of friction might be most desirable. In other duties variously higher coemcients of friction might be desired. Nothing here, therefore, can be said about any given coefficient of friction or hence any given compound. In any case, however, we here wish to emphasize that the static coefficient of friction and the dynamic coelcient of friction should be the same, should be balanced, or at least sumciently balanced to avoid setting up objectionable spasmodic actions, vibrations andnoises.

Also, the material, of which the spacing device is constructed, must be proof against detrimental faction of water or oil or other elements with which it is likely to come in contact. For certain indoor duties this factor might not be important. Most certainly, however, this factor is important in spacers -for use lin automobile springs.

From the foregoing it will be apparent that a successful workable spacing device for leaf spring duty must combine all ve of the factors as here set forth as the objects of this invention.

Y A preferred material for this spacer duty, and one which has amply proven itself in service as highly satisfactory for duty in automobile springs, is a woven cotton fabric impregnated with a compound comprising calcium stearate, a suitable solvent for same, such as stearic acid, and suitable plasticizers. The important ingredient in this case, because it provides the necessary bal- `ance between static and dynamic coeihcients of friction, is the calcium stearate. In this connection, reference may be made to U. S. Patent No. 1,845,096, granted to Robert F. Nowalk on February 16, 1932. With the calcium stearate as the mediumfor balancing the static and dynamic coefficients, numberless compounds can be made to provide such frlctional coefficients as may be best suited for different duties and conditions. In place of a woven cotton fabric as thematrix. excellent results have also been obtained by im- Dregnating suitably porous papers. The cotton fabric, however, is preferred at the moment as it seems to make possible a somewhat more sturdy and long-lived spacing device.

-canythe entire imposed load 'is carried by the succeeding array of spring tips, one tip passing Equipped with spacer devices as here set forth. it becomes unnecessary to 'cover or f'boot the spring. 'I 'he yieldable and self-sealing nature x ofv the spacersprovides all the protection neces- 5 sary against abrasive action and wear. `If desired,

short, thin metal spacers may be positioned between the leaves at the centre of the spring and held in position by the centre bolt. Thus there would be no interleaf rubbing contact and. therefore, no water, grit or grime could interfere with the smooth and silent action of the spring.

`Tests have demonstrated that grit or other matter, when dry, simply blows right on through between the spaced leaves. Ample tests have -ried in between the leavesand lodged there in the form of muddy water or mud, this matter will shake out or get blown out immediately the moisture evaporates and the foreign matter becomes dry. Not only, therefore, may the cost of spring covers be avoided, but also a better Job is had'without them because the most eilicient of spring covers still permits the -entry of foreign matter and then actsl to imprison and accumulate it.

our invention more specifically as applied to use in connection with a leaf spring, it should be understood that we do not limit ourselves to this specic use -of the invention asit is quite apparent that this novel combination is equally well adapted for use as a spacing means in numerous other mechanisms wherein two bodies i are'subjected to relative movements and pressure `and -wherein long-lived, smooth and silentaction is desired.

We claim:

1. For positionment between two frictionallv opposed members for controlling the friction therebetween, an impregnated fibrous spacing device provided with an integral, drawn and preformed projection for anchoring Vsaid device with relation to one'of said members, said projection having its wall portions substantially at right angles to said device.

2. For positionment between two frictionally opposed members for controlling the friction therebetween, an impregnated fibrous spacing device provided with an integral, preformed bou o portion for anchoring said device with relation to one of said members, said boss portion being reinforced by means to strengthen it against collapse. A

3. For positionment between two frictionally m, opposed members for controlling the friction therebetween, an impregnated textile fabric spacing device provided with an integral, drawn and preformed projection for anchoring said device with relation tov one of said members, said pro- O iectionY having its wall portions substantially at right angles to said device.

4. For positionment between two frictionally opposed members for controlling the friction therebetween, an impregnated textile fabric spacing device provided with an integral, preformed boss portion for anchoring said device with rela-` tion tovonev of said members, said boss portion being reinforced by means to strengthen it against collapse.

7o l v Jorn: WARREN wii'rsoN.

KENNETH W.

also demonstrated that if grit and grime are carwhile-we have here illustrated rand described Y

Images