US2032100A - India rubber spring - Google Patents

Description

Febg25, 1936. A. SPENCER INDIA RUBBER SPRING Filed NOV. 17, 1934 4 Sheets-Sheet l Feb. 25, 19136; A. SPENCER 2,032,100

INDIA RUBBER SPRING Filed Nov. '17, 1934 4 Sheets-Sheet 2 H 1 "Mm [WW 1 37 "9 5 353%; k/ lexajzoler $pe7wez;

Feb. 25, 1936. A. SPENCER INDIA RUBBER SPRING Filed Nov. 17, 1934 4 Sheets-Sheet 3 Feb. 25, 1936. A. SPENCER INDIA RUBBER SPRING Filed Noy. 17, 1934 4 Sheets-Sheet 4 Spank/e flaw a Patented Feb; 25, 1936 PATENT OFFICE mom RUBBER srnmo Alexander Spencer, Westminster, London,

' England Application November 17, 1934, Serial No. 753,540 In Great Britain October 29, 1931 23 Claims.

This application is filed as a continuation in part of each of my copending applications Serial Numbers 619,164, filed June 24, 1932, and 667,899, filed April 25, 1933.

This invention relates to India-rubber springs and more especially to India-rubber elements of the type disclosed in .my aforesaid applications for assembly on rigid foundation or supporting plates. The invention also relates to units comprising such foundation or supporting plates having the India-rubber elements thereon;

Heretofore, India-rubber springs for bufiing and draft gear and for other purposes have comprised a plurality of' foundation or supporting plates assembled in series with intermediate separating plates, each supporting plate having rectangular, oval or annular frames of India rubber projecting from its opposite faces. In my Patent No. 1,890,795 there is disclosed a spring unit, the India-rubber elements whereof are in the form of straight parallel bars, thereby simplifying the molds necessary for the manufacture of spring units and considerablyreducing the cost of production. When bar-type spring elements of the kind heretofore used are subjected to compression, the relative expansion transversely of the bar greatly exceeds the corresponding expansion in a longitudinal direction, with the result that such elements undergo greater distortion about their middle portions than at their extremities, with the result that such middle 1 portions are subject to undue wear and distortion.

A feature of considerable importance in connection with parallel-sided bar elements is that under compression they attain a maximum transverse dimension approximately centrally of the major axis, diminishing towards each end of the bar, that result being produced by the considerable resistance to longitudinal flow or expansion of the center zones of the elements by the adjoining terminal ends so that the bulk of the distortion resulting from compression is fixed to take place in a transverse direction, and, as aforementioned, such inherent asymmetry of bar type elements has the disadvantage that when'such elements are assembled on a supporting plate a mutual support is provided only at the central portions of the bars and there is no continuous mutual support between adjacent bars which would obtain should the side walls of the The primary object of this invention is to overcome the aforesaid disadvantages and to provide a construction of spring device particularly adapted for bufling and draft gear in which the spring elements thereof shall have mutual support on each side for the major portion of their length so that such elements may give a maximum eifectiveresistance under a predetermined compression and so that distribution of stress throughout the body of the elements will be more uniform and undue wear at the middle portions of the elements is avoided, whereby durability of the spring device is greatly enhanced.

'I'he India-rubber spring elements may be of various shapes and may be of a generally rectangular form, as shown in my aforesaid application Serial No. 619,164, or of a generally sectorial form, as shown in my aforesaid application Serial No. 667,899. Whether the elements are of generally rectangular form, or of polygonal form, if they are arranged adjacent one another on a foundation or supporting plate in a. predetermined relation, the sides thereof, when the elements are subjected to a predetermined compression, will meet each other in a straight line and provide mutual support throughout the major portion of their length. i

. Further and favorable objects will appear from the following description.

According to this invention, the India-rubber spring elements are waisted or reduced in the middle portion of their length to an extent insuring that the asymmetric distortion resulting from a predetermined load will cause the side walls of the bar to lie in a single plane and when 3 generally rectangular bar elements are utilized and such elements are subjected to a predetermined compression, the side walls thereof will become substantially parallel or equidistant throughout their length.

Whether the bar elements are of generally rectangular form or are of generally sectorial for, or of polygonal form the portions thereof projecting at each face of the supporting foundation or plate may be truncated or pyramidal in form and when the elements are of generally rectangular or generally sectorial form the ends preferably are made curviform whereby chafing and deterioration of the corner portions is avoided.

When generally sectorial-shaped elements are used, their wider ends may be so shaped in the static condition that when the elements are subjected to a predetermined compression they will describe an arc of a circle, and if the elements are 55 arranged on a circular disk with their narrow ends adjacent, the center of the several arcs may be the center of the disk. I

When applied to triangular-approximately equilateral-square or rectangular, pentagonal,

o tcthe-element, and further the elimination of I curvilinear junctions as it were inside theangle's, or preferably by cur-viform protuberances form-:.

hexagonal and similar polygonal basic shapes of element, the invention provides re-entrant sides the sharp anglesbetween adjacent sides by.'eased ingbosses encircling the angles which provide a greater area of support for the rubber at these locations and prevent the excessive wear and deterioration which is otherwise likely to occur,

,while simultaneously producing concavity in the side walls so that the equivalent re-entrant contour'is obtained.

Hitherto, where circular lIhdia-rubber elements "have been utilized, irrespect ve f the particular manner of disposition over the area of .the supporting plate-and irrespective of the shape of such plate; connderable wastage of available space betweenadjacent elements is an inherent defect of the circular form but this defect is avoided by the pelygonal form made practicable by this invention, as elements of polygonal form may be arranged to interrnesh in the manner of the cells of a honeycomb. v

. The present invention therefore also comprehends a spring unit consisting of a metal plate and re entrant-sided polygonal elements of In-. F dia-rubber at the faces of the plate so shagd and disposed relatively to one another that under 'a.

predetermined compression the juxtaposed side a walls of adjacent elements mutually ab-nt and 2 Projecting from each face thereof.

4 improved results obtained on deformation under In the drawings Fig. 1.is a perspective view of one embodiment of an India-rubber element.

Fig. 2 is an empiric illustration showing the stress resulting from reducing or waisting the central portion bf a bar-element of the form shown in Fig. 1.

Fig. 3 is an eievational view of a spring unit comprising a metal supporting plate having waisted bars disposed thereover in accordance with the disclosure of my copending application Serial Number 619,165, flied June 24, 1932, Patent No. 2,001,855, May 21, 1935.

Fig. 4 shows apluralityof units of the type shown Fig. 3 assembled on a draw rod with F separating metal plates between adjacent units and adapted for cushioning either buff or draw stresses.

Fig. 5 is arr elevatlonal .view of a spring unit having India-rubber spring elements of generally sectorial form disposed over'a circular supporting plate.

' Fig. 6 is a cross sectional view ohlinili-S of Fig. 5.

Fig. '7 is a view similar to Fig. 5 showing the use of india rubber spring elements of polygonal form. 1

Fig. 8 is a cross sectional view on line 8-8 of Fig. 7, and

Fig. 9 is an elevaticnal view of a quasi-rectangular spring unit also embodying India-rubber spring elements of polygonal form.

Referring now to the drawings, and first to the embodiment of the invention shown in Figs. 1 to 4.

and more particularly to Figs. 1 and 2, it will be noted that the bars I which are employed as elements for India-rubber spring units, have their side walls 4 and 5 waisted or reduced so as to have a transverse width substantiallyless than the portions lying adjacent the ends of the element, and that the'transverse dimensions of the elements progressively increase from the central portion of the elements to each end so that the major transverse dimension is in the immediate vicinity of each end.

As it has been found that in use rapid deterioration of the corner portions is caused by the high internal stress set up when the bar is distorted by compression, it is preferable to have the end faces of the bar of generally semi-circular or semi-ehiptical form, as shownat 6 and I, in

which case the major transverse dimensions of the bar, indicated at 8, are located where the circular end faces 6 and join the side walls.

When generally rectangular bar elements are subjected to a predetermined compression the'side walls of the bar, owing to a greater resistance to flow in a longitudinal direction of the bar, will become substantially parallel to each other, as will be apparent from the dotted showing at 9andl0ofFig.2.

Substantial operating advantages accrue from the use of elements having center portions of reduced diameter, while the durability and stability of the assembled spfings under compression is greatly; enhanced.

Referring now more particularly to Figs. ,3 and 4, it will be noted the spring units are secured to metal or other rigid. supporting plates l2 which comprise the foundation of the spring units which are assembled in series with metal to the rear of a coupler shank l5 and between followers l6 and I1 in the draft gear of a railway vehicle. a

The barelements I of from each face of the supporting plate l2 and the coincident bars on opposite sides ofthe plate are united by India rubber passing through perforations in the plate as shown at is.

Thebarsmaybedisposed inanyusual orap-. propriate manner about the surface of the supporting plate l2, although maximum stability and durability will be obtained if the quadratsd disposition forming the subject matter of my copending application Serial Number 619,615 is adopted. An example of such a disposition is illustrated in Fig. 3 where, as will be seen, the barsare disposed with their major axes normal to the, adjoining edges of the supporting plate 12. As shownin this figure, each of the bars of the parallel seriesof bars 26 have their longitudinal axes disposed normai or at right angles to the adjacent plate edge 2|, a facsimile of the parallel series20 being.disposed at the other side of the plate adjace the edge 22 and bein i dicated by reference character 23. Intermediate the" series 2|! and 23, and adjoining the top and bottom edges 24 and 25, respectively, of the plate l2, are two additional parallel series'of India rubber project spring elements 26 and 21, respectively, having their longitudinal axes vertical, that is at rightangl'esto their adjacent plate edges.

Each of the bar elements is of-the waisted section shown in Figs. 1 and 2 and have the expansion' characteristics there displayed, the side walls assuming the condition of parallelism under a predetermined compression, whereby maxirial No. 619,615.

For "certain purposes, as where the supportihg; foundation or plate is circular, oval, etc., it is preferable that the India-rubber elements conis obtained due to their opposed side walls coming into contact for substantially the full length of the elements when they are subjected to a disposition of the bars illustrated makes full use of the available surface of the plate I2 and assures a high degree of stability for reasons fully explained in my said copending application Sestituting' the spring unit and projecting ateach face of the supporting plate shall be of generally.

sectorial form. Figs. and 6 illustrate elements of such form secured to a circular supporting plate andthe unit thereby formed may be assembled in series with intervening separating plates in the same general manner as the units shown in Figs. 3 and 4 to constitute a spring for 'bufling and draft gear on railway vehicles or for' like purposes.

In Figs. 5 and 6 the India-rubber-elements which are of generally sectorial form are shown as .beingsecured to a circular supporting plate 3| having a central aperture 32 sufficiently large to receive a draw bar or the like. The generally sectorial blocks are disposed about the surface of the plate '3! so that their narrower ends are adjacent. Instead of the elements having their side walls disposed in radial planes when in the static condition, the elements, like the element shown in Figs. 1 to 4, have their central portions waisted or reduced so that their side walls assume a radial disposition when the unit is subing plates 3! and elements on opposite faces of the plate are united by rubber passing through perforations 35 in the plate. The elements Bil are of substantially uniform depth inthe direction of compression and have flat compression surfaces 36 in contact with the adjacent separating plates Bit-and 3 3.

Inasmuch as the transverse dimension of the elements adjacent their outer ends, as indicated at 38, is much greater than the transverse dimension adjacent their inner ends, as indicated at 39, the elements are formed so that their transverse dimension is not symmetrical as is the case with the waisted bar type elements shown in Figs. 1 to 4, and the elements are so formed that the maximum reduction occurs nearer their outer edge than at the. middle thereof, as is indicated at 60. When the spring elements thus have their side walls asymmetricallyredueed, the greater deformation under compression at the wider portions of the elements is compensated for and under predetermined compression the side walls of adjacent element will meet each other in a straight line as indicated at 4| and thereby mutually support each other.

With sectorial blocks, as well as with generj other thereover along the line 4!. '.tion of the elements to on the supporting plate 3| as shown in Fig. 5 not only provides for maximum mutual support between adjacent elements by ally rectangular elements, it has been found that undue wear and distortion occur at the corner portions, and accordingly, the sidewalls of the elements illustrated in Figs. 5 and 6 are so formed as to prevent a curvilinear outline, the junctions between the'side and end walls being reduced at 42, 43 and 44 whereby suchzwear' and deterioration is avoided. Y

The form assumed by the elementsunder compression is clearly illustrated in Fig. 5 where two of the blocks on the upper half of the plate are illustrated in this condition and it will be seen that their side walls have assumed a substantially radial disposition and mutually support each The disposirea'son of their opposed side walls coming into contact for substantially the full length of the elements, but it also makes full use of the avail ablesurface of the plate (and assures a high degree of stability.

It will be understood that the extent of reduc-= tion in the transverse dimension of the elements 30 about their middle portions, and the asymmetry of the recesses thereby formed in the side walls of the elements is dependent on the degree of compression at which the side walls are rethem to assume a radial disposition. The side walls of the elements illustrated in Fig. 5 will reach the radial disposition and be caused to .2.

mutuallysupport each other along the line Hl under compressions which reduce their depth by approximately fifty percent. The embodiment of secton'al elements illustrated in Fig. 5 also have their circumferential wall 45 flattened somewhat in the static condition, whereby under compression it presents asurface d6 substantially concentric with the periphery of the plate 3!.

Referring more in detail to Fig. 7, the circular metal foundation or supporting plate 58 is similar to the plate 3! shown in Fig. 5 and has a central aperture 5! for the passage of a bumng or'draw rod similar to'that shown in Fig. 4. At each face of the plate India-rubber spring elements 52 having'fiat compression surfaces 52 project and coincident elements at opposite faces of the plate are united by India rubber passing through perforations in the plate in the same manner as is shown in Fig. 6 in connection with the generally sectorial shaped elements. A plu ralityof units such as those shown in Fig. 7 are adapted to be assembled with intervening plates 38 and 3 5 of the same form as those shown in Fig. 6 to constitute a spring or cushion device forbufiing and draft gear in railway vehicles or for other purposes and when so assembled the flat compression surfaces of the India-rubber elements will contact with the intermediate separating plates. i

In Fig. 7 a unit having five India-rubber spring elementsprojectingfrom each face of the plate 50 is shown and the several elements have the same shape and size and are uniformly distributed about the plate in the same general manner as the generally sectorial elements 35 are distributed about the plate 3! in Fig. 5. However, in Figs. '7 and 8 the basic shape of the elements is triangular with the apex of the elements disposed adjacent one another 'at or about the center of the plate.

In contradistinction to the elements shown in Fig. 5, the generally triangular elements of Fig. 7

are substantially symmetrical in form. That is, the outer side or base 53 of the triangle is sub- ,stantially equal in extent to-the side or radial walls 54 whereby the basic-shape of the elements are equilateral triangles and more uniform distribution of stress throughout the body of the elements is obtained. For reasons already pointed out in connection with the from of ele- 1 ments shown in the preceding figures, the curviform junctions 55 are formed between the side which have central circularapertures.

' Like the side walls oi" the elements shown in the preceding flgures,the side 'wallsof the elementsshown in Fig. 7 are reentrantor curved inwardly so that under apredetermined com-.

pression" they will assume a substantially planar or radial disposition asindicated at 55 where the dotted line represents the formwhich the several elements assumedv when they are. subjected to a predetermined pressure applied normal to theflat compression surfaces andfrom the dotted line it will be noted that the form of elements shown in this figure also provide the mutual support for one another when the ele-.

ments are placed under compression.

The degree of inward curvature of the side walls 54 of the elements and the radial spacing between the respective elements will bev dependent on the compression at which it is desired that mutual support will take place, that condition being accelerated by arranging the juxtaposed side walls 54 of adjacent elementsin closer.prox-' 'imity when correspondingly a small degree of inward curvature is necessary.

The outer or peripheral wall 53 of each element may or may not'be made reentrant depending upon theparticular form of foundation plate which is used. As shown inFig. 7, the peripheral walls 53 are notmade reentrant as a circular foundation plate provides a, greater free 7 space for distortion at the central portion of said side walls. However, when the peripheral walls are not made reentrant, it is preferable. that theybe so shaped that under a predetermined compression at which the juxtaposed side walls 54 come into contact with each other; as along the line 55, the peripheral walls will be substantially concentric with the circumfere'nce'56of. the plate as shown in 51. This may be accomplished by forming the peripheral side walls 53 on a radius somewhat greater than the radius of the circular Plate-o that these walls will be flattened rela-- tive to the circumference 55 of the plate.

The symmetrical and substantially equilateral form of the elements 52 permits each element to be united to its coincident element. at the opposite face of the foundation plate 50 through three plate apertures 53, 59 and 63 disposed adjacent the inner and two outer extremities respectively of the element, and therefore widely distributed over the area. thereof so as to provide a firm and .secure anchorage. 'A further advantage of such a,os2,1oo I by provided are so located as to best resist the natural outward thrust occurring when .the compression exceeds that at which the opposed side walls come into contact. t

- The formation of the elements 52 into substan- 5 tially equilateral triangles also provides an eifective covering of the supporting plate under the compression at which the sides of adjacent-elements abut and mutually support each other as is clearly'evidenced by the dotted lines shown on the upper half of the plate in Fig. 7 and from that figure it will be noted that only a very small portion of the area of the plate adjacent. the central aperture 5| and adjacent the periphery 58 remains uncovered. 1 i V ,-'Ihe adaptability of the generally sectorial form ofelements shown in Fig. 5 or thequasitriangular symmetrical elements shown in Fig. 7 to supporting plates having shapes other than I circular is exemplified by the embodiment of the invention shown in Fig. 9 where a plurality of quasi or:generally triangular symmetrical India'- rubber elements are assembled upon' a, quasirectangular supporting plate 62 having apertures 83 and 64 for the passage of retaining or central izingrods. It will be understood that thelunit disclosed in this figure will constitute one of a plurality of such units which 'will be assembled A in series to form a cushioning device of 9. putting and draft gear of the type generally indicated in Fig. 4.

The lndia rubber elements 55 shown adjacent the apertures and and the ends 65 of'the quasi-rectangular supporting plate 62 of the same characteristic form as those shown in Figs.

'Iand 8 and have inwardlycurved opposed side walls 61 and inwardly curved inner walls 68 adjacent the apertures 83 and 64. However. the

elements 65 differ slightly from the elements 52 shown in Fig. 7 as'the outer sides 59 are also made reentrant, or inwardly curved, whereas the peripheral walls. 53 of the elementstshown. in Figs. 7 and 8 were not made reentrant.

The elements III, II and I2 disposed in'alternate series along the top and bottom edges 15 and 14 of the plate 62, while retaining the general characteristics of the form of elements shown in Figs. 7*and 8, are more nearly trian'gu larin shape as none of the apices are provided with the double curviform wall"68 which those elements and the element 65 have. v f Centrally ofthe plate -62, between the apertures 65 and 54, a waisted bar'element 15 of the the space available between the two elements It 55 is insuiilcient in the particular shape of the supporting plate 52 illustrated accommodate a symmetrical element similar to the elements 55 andIOJIorH, I

Each of the elements 55, )10, H and 12 have three point anchorages or unions to their coincident elements .at the opposite face of the plate 62 thereby insuring durabilityand freedom from likelihood of displacement in use. y

The dotted lines shown in' the upper half of 65 Fig. 9 clearly disclose how the adjacent elements .mutually abut and support each other-whenthe India-rubber element's are subjected-to a predetermined compression, and also how mutual contact takes place over substantially the whole of the juxtaposed side walls of adjacent elements to givemaximum resistance to further movement under compression. havin shapes other than that disclosed in Mg. 9 are Where non-circular supporting plates form shown in Fig. l is'secured'to the plate as ments which, under stress, assume a form such used, India rubber of other symmetrical shapes and sections may be employed which will best suit the configuration of the plate with which the elements are to be associated to form a spring unit whereby efl'ective covering of substantially the whole of the available area of the plate under compression will be assured with maximum mutual support between the several elements, and uniform distribution of stress throughout the bodies of the elements will be obtained.

Whether generally rectangular, generally sectorial, generally polygonal, or other shaped, India-rubber spring elements or bars are used, it is preferred to employ elements having waisted or reduced center portions, but it will be appreciated that the invention in its broader aspect comprehends any formation of India-rubber elethat, when the elements are suitably arranged upon the carrying plate, the opposed side walls of adjacent elements may afiord each other mutual support.

I claim:

1. An element for an India-rubber spring com- .prising a solid member of Indian rubber of substantially uniform depth in the direction of compression, said bar having substantially flat compression surfaces and having its major axis between said surfaces and substantially parallel thereto, said member having portions adjacent each end ofsaid axis of greater transverse dimension than a transverse dimension intermediate said end portions, whereby under a predetermined compression the lesser intermediate transverse dimension will be caused to become at least equal to the transverse dimension of at least one of the end portions.

2. A bar element for an India-rubber spring comprising a solid bar of India-rubber of uniform depth in the direction of compression having flat compression surfaces and having its major axis between said surfaces and parallel thereto with the portion at each end of said axis of greater transverse dimension than its centre portion such that under a predetermined compression the side walls of the element become substantially parallel or equidistant from each other throughout their length.

3. An India-rubber spring element comprising a solid bar of India rubber having fiat compres sion surfaces with its major axis lying between said surfaces and parallel thereto and its side walls curved inwardly in the direction of its length so that the centre portion of the element is of smaller transverse dimensions than the portions at the ends of said axis when in a static condition such that under a predetermined compression the side walls become substantially parallel or equidistant throughout their length.

4. An India-rubber spring element comprising a solid bar of India rubber having flat upper and lower compression faces and its major axis lying between said faces and parallel thereto and vertical side walls with curviform ends said side walls being inwardly curved longitudinally of the bar to reduce the transverse dimension of its centre India rubber moulded to opposite faces thereof,

coincident bars being united through said perforations, said bars being of uniform depth and in thestatic condition being of reduced transverse dimensions about their middle portions such that under a predetermined compression opposite side walls become parallel, and said bars being located in parallel juxtaposed relation so that the side walls of adjacent bars are brought into contact for substantially the whole length thereof, whereby mutual support of the bars by each other is obtained.

6. An India-rubber spring unit comprising ,a metal plate, perforations in said plate, bars of India rubber moulded to opposite faces of said plate, coincident bars being united through said perforations, said bars being of reduced transverse dimensions about their middle portions such that under a predetermined compression opposite side walls become parallel and said bars being located in groups of parallel juxtaposed bars so that the side walls of adjacent bars of each group are brought into contact over substantially the whole length of such bars, whereby mutual support of the bars by each other is obtained.

7. An India-rubber spring element of general sectorial form and of uniform depth in the direc-. tion of compression having flat compression surfaces, and its major axis between such surfaces and parallel thereto, with its side walls curved inwardly from the radial in the static condition such that under a predetermined compression they assume substantially a radial disposition.

, 8. An India-rubber spring element comprising a solid block of general sectorial form and of uniform depth in the direction of compression with fiat compression surfaces and its major axis between such surfaces and parallel thereto, having its side walls curved inwardly from the radial in the static condition such that under a predetermined compression they assume substantially a radial disposition, and having curviform walls joining its side and end walls whereby the ele ment presents a curviform outline and stress is more uniformly distributed throughout the body of the element.

9. An India-rubber spring unit comprising a metal plate, perforations in said plate, spring elements of general sectorial form and of uniform depth in the direction of compression with flat compression surfaces and their major axes between such surfaces and parallel thereto, at opposite faces of said plate, coincident elements being united through said perforations, said elements being radially disposed to juxtaposed relation on the plate and having their sidewalls curved inwardly from the radial in the static condition such that under a predetermined compression their side walls assume substantially a radial disposition with the walls of adjacent blocks in contact, thereby providing mutual support for all elements of the unit over substantially the whole length of eaclr'element.

10. An India-rubber spring element of general sectorial form having opposed compression surfaces, the sides of said element in the static condition having recesses therein, with the recesses extending further inwardly at the wider end of the element than at the narrower end, whereby upon a predetermined compression the respective side walls will assume a substantially planar disposition throughout the major portion of their length.

11. An India-rubber spring element of generally sectorial form having opposed compression surfaces, the sides of said element inthe static condition having recesis lesv therein, with the re 10' 7, said element lying between said parallel surfaces cesses extending further: inwardly from the radial at the outer ends theref than at the inner ends, whereby upon '9. predetermined compression the side walls assurne a substantially radial disposition. p

12, An Indiairubber spring element of generally sectorlal form and jof substantially uniform compressibility; having substantially parallel opposed ,eompression surfaces, the major axis and substantially parallel thereto, the sides said element in the static condition having m cesses therein, with the recesses extending fur: ther inwardly from theff radial at the outer ends thereof than at the inner ends, whereby under ii a predetermined compression the side w'alls as- "pression' the sidewalls assume a substantially rubber elements of generally sectorial form car sume a substantially radial disposition;

13. An India-rubber spring element; of generally sectorial form and of substantially uniform depth and compressibility, having oppoeed com- 'pression surfaces, the sides of; said element in the static condition having recefsses therein, with the recesses extending further inwardly from the radial at the outer ends theredf than atthe inner ends, whereby under a predetermined comradial disposition, the fnds of said element being curved whereby stress: is more uniformly dis-- tributed through the Epdy of the element.

14. A spring-unit coinprising a plate, Indiaried b said plate, said'j elements having opposed co I ssion surfaces; the sides of said elements in the static cpnditior having recesses therein, with the recesses extending further inwardly at the wider endjof the element than at the narrower end, whereby under a predetermined compression the respective side walls of the elements will agsume a substantially planar disposition throughout a major poiition of their length. i .15. spring unit comprising a plate, India..-

rubber; elements of generally sectorial form can ried by? said plate, said elements having oppose-:1

, compression surfaces, the sides of said elements inthe static condition, having recesses therein, with the recesses extendin'glfurther ginwardly from the radial at the outer ends thereof than at the innerends, whereby under a predetermined a compression the side walls of the elements as sume a substantially radial disposition,

16. A spring unit comprising a plate, Indiarubber elements of l'generall; sec'torial form and of substantially uniformQdepth and compressibility carried bysaidplate, said elements having opposed compression surfaces, th sides r said elements in the static condition hving" recesses therein, with the recesses extending lfur ther inwardly from the radial at the outer ends thereof than at the inner ends, the'ends ofsaid elements being curved whereby the elements present a curviform eutline and stress is more uniformly distributed throughout the bodies of the elements, the spacing of said elements on the plate being such that under va predetermined compression the side walls assumesub'stantially a radial disposition with the walls of adjacent blocks-in contact, thereby providing mutual suppart fer all elements of the unit over substantial- 70 ly thefwhole length of each elemen v l7. gl spring unit comprising'a'rigid plate has; ing perforations therein, India-rubber elements of generally sectorial form attached to each 182% aosaioo of the plate, coincident elements being connected by integi'al portions thereof extending through the perforations the, elements having substantially parallelopposed compression surfaces, with the major axes of the elements lying between said ;surfaces and substantially parallel thereto, the sides of said elements in a static condition having recesses therein; with the recesses ex.-

tending further inwardly from the radial at the outer ends thereof than at the inner ends, whereby under a predetermined compression the side walls of the elements assume substantially a radial disposition. V

18.:An India-rubber spring elementmomprlsing a substantially equilateral polygonal body of India rubber having flat compression faces and its static condition, whereby stress is'synimetrically distributed throughout the body of the element under compression and under a predetermined compression the side walls assume asub-planar I disposition. g

19.- An India-rubber spring element according v to 18 wherein the area of support for the India rubber at the junctions between adjacent side walls is augmented by curviform protuberances simultaneouslygproducing concavity in .the side walls and preventmg the excessive wear and side *walls re-entrant' or curved inwardly in-the deterioration otherwise likely 'tooccur at the junctions therebetween.

20. An India-rubber spring element according -to claim 18 having the basic shape of an equilateral triangle with the angles between adjacent sides eased by curvilinear junctions, wliemby' symr netrical distrlbution of stress obtains under compression. g 22 21, An India-rubber spring unit comprising a metal plate having a central aperture and per- 'forations between said central aperture and the periphery thereof, and India-rubber spring ele--' ments of generally sectorial form at opposite faces of the plate, coincident elements being united by India rubber passing through said p-erforations, the radial walls ofsaid elements being so shaped in the static condition that under a predetermined compression me side walls of adjacent elements mutually contact over substantially the whole of their length, the inner ends of said elements having a doubie. curviform contour with a part thereof reentrant to an extent which, under a predetermined compression, Willi cause. i the inner end of the elements to follow approxiportion ,of reduced transverse dimension. 7;

An India-rubber spring element comprising a harof India rubber 'moulded andfvulcanized a circumferential groove adapted to interlockingly engage a slotted supporting plate, having ilat upper and lower'substantially parhllel compression faces terminating symmetrical.

wedge-shaped compression-bodies of India rubber aboye and below said groove and having -curviform ends and its centre portion of reduced ,transverse dimension.

SPENCER.

Images