US2328877A - Cushioning device - Google Patents

Description

' sept. 7, 1943.

CUSHIONING DEVICE y J. P. GYALLAGHER 2,328,877

Filed .July 14, 1959 :a sheets-sheet 1 1 a.

INVENTOR Jol-1NA l? GALLAGHER ATTORNEY Sept. 7, 1943.

AMW

J. P. GALLAGHER CUSHIONING DEVICE "Filed July 14, 1939 2 sheets-sheet 2 W' y fa v INVENTOR JOHN R GALLAGHER ATTORNEY Patented SeptL` 7, 1943 UNITED STATES PATENT n OFFICE John J. i Application :Illy 14, 1939, Sel'lll N0. 284,386.1.

21 claims. (ci. A2er-c3) a L. The inventionfrelates to a cushioning-'device e, of general application for use in those situations :11 where cushions and springsv have heretofore been ,.used, and the invention specifically relates to a cushion, shock absorber orl similar motion re- -tarding device designed to cushion, stop, retard or soften the movements of bodies, particularly bodies having large vertically directed momentum asin the case ,ofY the resilient mountings h of railroad car bodies on their trucks, or, inthe case of'horizontally. directedV momentum, such as bumpers' or the retarding elements `of draft gears designed to cushion rpowerful impacts between adjacentcars. y More specifically deiined, the invention relates to a rubber cushion which may be `used-alone, or in combination with metalsprings, orwith friction elements, to form an improved character of cushioning device which will not possess certain defects inherent in such devices which depend alone upon metal springs as theircushioning elements. e

The primary object of the invention is to provide a simple formof cushioning element which will provide for a progressive andv definitely uniform accumulation of resistance to `compression forces acting n the same and at the same time to provide a form of cushioning element in which the recoil action thereof when released from such compression forces will not set up in the cushion fthe oscillatory vibratory movement inherent in metal springs of equivalent cushioning capacity. Broadly this invention features the use of a block of resilient material, such as-rubber, as a cushioning element and which block is provided outward distention.v Suchcushions have not proved entirely satisfactory among other reasons because they did not provide for any uniformity signed with a non-cylindrical form to provide for lated resistance to being distorted, -or to provide for a variable degree of resistance to meet those situations where the desired rate of increase in resistance to distortion is not strictly uniform.

In its specic application to a body mounting for a vehicle. the invention has for an object the providing of a cushioning device which will tend to resist transmission of short vibratory actions such as truck or underframe vibration to the supported body, and at the same time to provide a for-moi cushion which will resist gross bodilir movement between the vehicle body and the truck or underframe supporting the same as these parts tend to approach each other andwhich will not eiIectany sudden recoil action between the parts should the compression forces be suddenly removed and on the contrary will ease the return movement of the car body up toits normal position without settingup prolonged oscillations.

In its specific application to abumperr snubber, draft gear or similar mechanism, particularly those designed to resist powerfully acting movements over short distances, the invention has for an object the providing of a simple form of cushioning device which will bei free of the disadvantages inherent in the present known form y of such devices which depend upon metal springs in, or, any means for-regulating, the accumulating resistance.

The present invention constitutes an improvement over these forms of rubber cushions in that the cavities or core holes extending therethrough are not of the known pencil-like cylindrical form which have a, uniform` diameter' throughout their lengths but, are carefully deand will possess not only the advantages inherent in the rubber block as above outlined, but will also utilize the rubber block as 'a force translating device for actuating the friction shoes of a friction brake so that the complete structure will be a combination of rubber resistance and friction resistance to the actuating force to be cushioned. f

Various other objects and advantages of the invention will be in partobvious from an inspecv tion of the accompanying drawings and in part will be more fullyset forth in the following particular description of one form of car mounting embodying the invention and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawings:

Fig. 1 is a vertical sectional view taken axiall through a car body mounting and includinga cushionconstituting a preferred embodiment of the invention shown in its normal distended position and illustrated-.in connection with vibratory insulators4 to form a cushioning -unit located between a vehicle truck and a car body-shown in ghost outline, and also showing a dotted outline at the left and right sides of the gure two succeeding forms of the end portions of the core holes as the cushion is compressed to the extentl indicated by the dotted outline;

Fig. 2 is a view similar to Fig. l showing the relation of the parts and particularly the finalA` configuration of the core holes beyond the dotted line positions, and when the block has been compressed to a desired limit; f

Fig. 3 is a view in axial section of a form of the invention featuring the use of a rubber block utilized in combination with friction shoes to provide a bumper, snubber, or shock absorber; and

Fig. 4 is a transverse sectional view taken on the line e-f of Fig. 3.

In the drawings and referring first to the disclosure in Figs. l and 2, there is disclosed a. vehicle truck I shown symbolically by its spring plank II and which truck is designed to support a car body I2 shown symbolically by its bolster I3, the support being effected through a cushioning device I4 including a rubber block I5 particularly constituting the novel feature of this disclosure. l

The cushioning device I4 includes an open end feat or at least minimize the vibrations of small amplitude and thus interrupt the flow-of vibrations between the wheel truck and the car` body and to this extent function in a manner similar to the rubber bearingsnow in use on railroad trucks.

The two heads are each provided with a cen- V tral bolt hole 30 forming a continuation of the associated bolt holes 28 in the insulators and with a plurality of air vvents 3I arranged in a circle about the axis of thrust indicated by the line a--b and open to the external air through the air vents 29. A tie bolt 32 connects the `centers of tubular band or cylinder I6 and which in theA Fig. 1 disclosure is of cylindrical form and preferably is formed of steel or some other rugged material having sufficient structural strength to restrain radially, outwardly directed distortions of the rubber block I5 fitted therein. For the purpose of resistingany tendency of the rubber block from creeping out of its centered position in the cylinder, the cylinder is provided adjacent its mid-helghth with an inwardly extending annular rib I1 forming a locking means in its engagement with the corresponding annular groove I8 encircling the outer cylindrical wall I9 of the rubber block and formed therein as an incident of the molding of the rubber in the cylinder forming band. Thecylindrical rubber block terminates at its upper end in av iiat pressure receiving end-face 20 spaced slightly inwardly and downwardly frornthe adjacent end of the cylinder I6 and, similarly, the bottom end face 2| of the rubber block is spaced slightly inwardly and upwardly from the lower end of the cylinder.

Fitted in opposite ends of the cylinder is an upper head 22 and a lower head 23 of similar construction and in4 this form of the invention both heads constitute plungers snugly but slidably mounted in opposite ends of the cylinder.

It is within the scope of the disclosure, however, to secure one of the heads to the cylinder, to form a closed end to one end of the cylinder, leaving the other head to function as the compression effecting plunger.

Fitted within the upper head 22 is a layer 24 of relatively hard rubber molded into a shallow recess 25 formed in the head and secured in place by a rib locking engagement 26.v The layer 24 projects `a short distance above the head 22 to engage the underside of the bolster I3 which rests firmly on the layer 24. Similarly a layer of relatively hardy rubber 21 is fitted in or molded into, locked in, and projects below the lower head to rest onl top of the spring plank II. Both layers are provided with a centrally located bolt hole 28 and with a plurality of air vents 29 extending therethrough for a purpose hereinafter described. These two layers of rubber are not primarily intended to function as devices for cushioning gross body movements but rather as insulators to dethe two heads and is arranged to limit the relative separating movements of the heads. 'Ihe rod is mounted in position, passed through the bolt holes and has its lower bifurcated end spread to provide a stop at the end opposite the bolt head. In mounting the tie rod in position, care is exercised to insure a firm, snug engagement; of the heads 22 and-23 with opposite ends 20 and 2| of the rubber block.

The rubber block is provided with an'axially located core hole 33 surrounded by a plurality of elongated cavities or supplemental core holes 34, at least four in number, extending with thehole 33 lengthwise of the axis of thrust a-b, and arranged in a circle of which the axis a-b is the center. It is the particular feature of this disclosure that the core holes 33 and 34 are of double frustum, hour-glass or Venturi tube form but not necessarily of frusto-conical form. Diierently described, the holesI are of minimum cross sectional area adjacent their mid-lengths in the plane indicated by the line c-d and gradually increase in cross sectional area progressively towards their opposite ends in the faces 20 and 2|. This form of cavity or hole through the rubber block forms in effect strain transmitting columns 35 of rubber which have relatively small masses of material adjacent opposite ends, that is, in the top and bottom zones which are the regions which rst become compressed. The cross sectional area of rubber gradually and progressively increases in cross sectional areas in the direction ,v

pressive forces meet along a transverse plane approximately equidistantly spaced from the opposite end faces 20 and 2I of the block and in the zone centered about the -plane c-d. The outlining circular edges of both faces are rounded as indicated at 36 to defeat any tendency of the rubber vto creep into the joint formed between the cylinder and the plungers.

In operation and assuming that compression forces acting between the truck and car body causes the heads 22 and 23 to approach each other, the initial movement of both heads will be to compress at least the rubber which forms the adjacent end zones or layers.. The axially directed compressive forces acting on each end zone will resolve themselves into radially directed components which will vtend to distort the end zones and as the rubber which is noncompressible is restrained from outward movement it must necessarily move inwardly 'into the cavities or core holes. This has the effect of causing an inwardly or radially directed distortion of the-rubber into the end portions of each of the 'core holes so that, they tend to assume rst the form shown ber columnswhere there is the least amount of rubber and thus the block is" offering its leastresistanceto distortion and its leastresi'stance to the action ofthe compression forces present. lIt therefore follows that the initial cushioning action v.in resisting thel compressive @forces isjrela` tivelyweak.'` ,d f Q t Asthe plungers continue to move towardseach other. `progressively"moreandI more interidr zones' d Qf. .th` llibbelwu bom' nYolved. a df'Sla-r dially outward ,moy/ement, restrainedfby' the cylinder "wall "I 6" the;` :rubber blockf` 'j become more v.and more distzg'rtedjinterr'iallyand w Y eiiectfiowor rather distend into thefspace's vided'for'the same by thefcoije holes as indica Vd L inthe fdottedjnn'e snowing tothe yright of 1.` Eventually the limitr of 'compression W be reached and at which timelthe core' t ,hiewiutave the substantially uniform diamertefredL and: cyl-in;

drical form shown in Fig'. l Unlessfther're holes havebeen designed Vwith variable crossfsec-y tional areas along their lengths as herein suggested, this nal cylindrical form will not be attained. Thefdegree of incline or slope' to the frusta-conical ends of the'core hole'sis dependent upon the size and material of the block and this in turn dependsupon the character andintensity of the compression forcesgwhich the'de-` vice is intended to resist. In the illustrated sure imposing` elements such as the jplunge'rs'- 22 and 23. It isdsuggested thatin place of a singledV block there be substituted two or more such blocks arranged as replaceable funits in columnar form one "onthe other. siichfcase,v it is pref'- erable that thenrubfber oi!A neunit beseparated fromthe rubberfforming 'the 'adjacent unitor so as to.i avoid a rubberfto-rubber contact andV at' the same timetopermiteach to function las ii' it were `alone'. ,'1lhis isgbest attained by facing the pressure receiving faces of thelrubber blocks with 'Vmetalface plates secured thereto so thatfa unit will comprise a rubberblook 'and twov faceplates one foreach of the opposing faces of the "rubber' block `san'dwiched therebetween.` f i i `It has been found especially inthe casewhere one' ofthe heads is 'xed inthe plunger cylinder 'that the mid-portionofthe rubber block V tive'sleeveor shoe encircle the rubber block at' the placewwhere such abrasion is "most apt to occur. It has also been found that vit is dimcult to avoid the creeping of the rubber'past the J'Oint'between the rubber andthe plungers and showing, the sides of the cone shaped ends form a ten degree (10) angle with their axis. In order to insure the gradual accumulation of resistance, care is exercised in designing the core holes, relative to vplunger'- travel, so that they will accommodate all of the rubber`l displaced into the same and lapproach but notfpass beyond ythe cylindrical form shown in Fig. 2 by the time the plunger has reached the limit of its travel. `It is' not'desirable to have the walls outlining the core holes pass inwardly beyond` y the `cylindrical form as any su`ch further inward movement would produce an irregular accumulation of resistance and develop disintegration of the rubber. l

. Itis seen that the core holes are ofthe double l frustum form; with the widestbase at the two pressure receiving faces and the smaller base along the common plane e-f.

On the release of the compression forces in lany of the illustrated forms of the disclosure,

ally diminishing recoils or oscillations which would characterize the device ifa metal spring was substituted for the rubber block.

yIt is suggested that a non-compressible subin order to avoid this the end edges ofthe rubber were cut away as'shown at 36 in Fig. 1. other way to avoid any .such seeping of the rubber out 'of the compartment in which it is contained is to fit rugged retaining rings' at the When it isdesired to limit the approach of the pressure" heads towards each other,Y it is suggested that Ia `rigid metaltube or rod 85 be located in one or moreof the holes as indicated in Fig. 1. By varying the length'of the rod85, the

approach of the heads may be regulated as de` sired. Likewise, the diameter of the rod will limit the contraction and final shape of the core hole 1 in which it is contained and thus' will function as has been described for the liquid core 52. Further, as the rubber engages the rod 82 particularlyfduring the final stages 'of its compresd sion it will grip the rod and thus create a fricstance preferably a liquid which may be water f or liquid rubber may be introduced in such premeasured amounts that it will completely fill-'its associated cavity when its desired nalform has been reached, after which theAr liquid 'core will act in effect as a solid to resist any further inward distortion. of the portion of, the rubber which outlines the core holes.

. As an illustration of such a, structure, refer- `ence is made to Fig. 3 where a measured amount 4o fiuid rubber 52 is'containedin cavity |02 and which cavity has its opposite ends closed by plugs 54 either cemented or vulcanized inl place. In, the several .disclosures as .thus far def scribed reference has beenY madeto the rubber block as singleunits havingtheir ends exposed and arranged to be squeezed between they prestional resistance to relative movement between the metal rod and the rubber. block.

In the'showing of the springless combined rubber and frictional resistant device shown in Figs. 3 and 4, there aredisclosed two metallic heads 86 and 81 of identical constructionand disposed in looking-glass symmetry on opposite: sides of the medial plane ef. Each head includes an outlining barrel-like projection 88 of cylindrical form,I the' inner face of which is on a raised ,wearing portion which provides a friction surface. The friction surface may be replaced when worn and for this purpose Vthe raised portion is shown to be a sleeve 89 of wear resistant material; Each head is also provided centrally thereof withaninwardly extendingboss 90 which forms between itself and the wall 88 an annular recessfilla .Fittedbetween the bosses 90-of the two heads is a block or core 92 of rubber and which maybe of any of theforms hereinbefore described;and likewise located to resist'relative movementof the heads towards each other. .In

thetformv-illustrated, theV rubber block is pro. vided with a hole 9 3 .extending axially there-V through. A tiebolt 94` ispassed through-the hole- 93vand throughthe bossesli tov limit the sep arating movement vof the heads, fromeachother- 'as is common in draft gear and similar, known snubber structures. The rubber block is surrounded completely by a sleeve forming structure which projects at opposite ends into the recesses 9| and has its -ends spaced from the bottoms of the recesses a distance suiilcientto provide for the requisite amount of approach permitted the heads under the circumstances surrounding the use to which the device is to be put. This sleeve is split to form a plurality, in this case shown to be three, friction shoes 95, 98 and 91, having their oppoiste ends in at least a light bearing engage,-y ment with the friction surfaces at 89. There. is thus provided a frictional brake which resists the approach of the heads88 and 81 with an intensity of engagement hetweenthe movable shoes and the fixed cylinder walls at least approximately proportionate to the forces which are causing the heads to approach each other. The adjacent edges of the shoes lap one another` as shown at 98 to permit the desired freedom of relative movement between the Ashoes considered circularly as shown in Fig. 4 and at the same time to defeat any'tendency of the -rubber of the block to creep into the joints formed between the shoes. Split rings 99 and |08 are located at opposite ends of the rubber block in the corners provided by the bosses 90 and the ends of the shoes in order to prevent lcreeping of the rubber into the joints formed therebetween when the rubber block is subjected to the compressive forces which such devices are intended to cushion,

Each shoe is provided centrally thereof withV an inwardly extending projection |0| fitted in a similarly shaped recess |02 formed in -the adjacent cylindrical side of the rubber block ad.

jacent its mid-waist portion. A plurality of core holes numbered ID3-|08 similar tothose shown at 34 in Fig. 1 extend through the block and are arranged in concentric order about the axis of the assembly. It is also suggested that restraining rings |81 and |88 be fitted into opposite ends of the block to encircle the bolt 94 and prevent seeping of the rubber out through the joints at these places.

In operation and assuming that the heads are caused to approach each other bythe forces which are intended to be cushioned, the bosses 90 will 'act on the rubber block to distend the rubber outlining the holes Hi8-@|88 inwardly into the same as has been previously described in discussing the Fig. lshowing. At the same time the' compressive forces acting on the heads will be resolved into an outwardly directed component and this outward distention of the rubber will act to move the three 'shoes radially outward each into engagement with the friction surfaces provided by the cylinders 88 if these shoes are not already in engagement with' their fric- I tion surfaces in the original set up oi.' the assembly. In either case the shoes will be pressed into a firm bearing engagement with thefriction surfaces provided by the two heads. This ra' dially directed force will increase as the 'heads approach each other and until it maximum when the heads reach t e limit of their'desired travel. It follows then that any movement of the heads toward each other, even Vfrom the very beginning-of their vapproaching movement and certainly after the frictionalengagements havebecome effective, the shoes, which under these circumstances are held substantially fixed in space relative to the plane e-.-f will impose a frictional' resistance to the approach of the heads 88-81 so that the heads are cushioned in their relative movement not only by the resistance to distortion or change of configuration inherent in the rubber block but this movement is also resisted by the accumulating frictional resistance between the shoes and the heads.

While this description assumes both heads to' lbe moving, it is obviously possiblev to fix one head say the head 81 and move only the head 88. Considering the condition at any instant of time while the heads are approaching each other, it will be obvious that the force acting onv the rubber block will be the force inherent 'Ihis is at that time in the approaching heads. the force which resolvedinto two components acts on the block in two radial directions, one component acting to overcome the resistance offered by the rubber to being distorted and thel time, the radially outwardly directed forces a'ct-V ing upon the shoes have either been entirely r'e leased or at least relieved, depending upon whether or not the rubber vblock is at all times under distorting stresses to keep the shoes in their bearing engagement. n

While the wear sleeve 89 may be mounted in place simply by means of a snug drum't which will permit its removal and replacement when worn. it is suggested that the associated head be heated to effect the necessary expansion to permit the insertion of the sleeve so that, in cooling, the head `will grip the sleeve 89 rrnly in place. It is also suggested that the sleeve be locked in place in the head by welding the sleeve to the head as indicated at |22 in Fig; 4.

In this disclosure, the term rubber is used `in a generic sense to include any elastic material capable of imposing resistance to being distorted and which will automaticallyrestore itself to its original form ,when free of the lforces which caused its distortion, irrespective as to whether in solid or divided form and which will restore itself automatically to its initial conguration without setting up vibrations therein das in the case of metal springs, and, further, the expression rubber includes not only the usual homogeneous- India rubber. or similar products containing caoutchouc or equivalent' rubber compositions but also includes nonhomogeneous and non-metallic elastic materials as wellas air containing elastic materials such as sponge rubber. I claim:

1. In a vehicle cushioning device, the combination'with a spring plank and a bolster above the plank, of acushioning device resti g on the plank and on whichv device the bolster rests,

said device including a rugged metal open band, a block of rubber fitted in the band, means for locking the rubber block in theA band against axial movement therein, a lower head fitted in the band.' an upper head fitted in the band, said heads mounted in the band for relative axial movement. a-layer of rubber forming a. vibratory insulator fitted within the lower head, de-

pending therefrom and forming a cushion for 75 dampening vibrations between the lower head and the spring plank, another layer of rubber forming a vibratory insulator fitted within the upper head projecting above the top thereof y and forming a cushion for dampening vibrations between the upper head and the bolster, and said rubber block and insulators provided with internal air pockets. v

ward distortion when the pressure faces are sub- A jected to a-squeeze pressure.

tional area in the portions adjacent the vplungers Y than in the portions adjacent:` their mid-portion to provide an hour-glass-like constructionto the several holes intermediate their ends.

3. A cushioning device including an outer tubular member, a block of rubber havingv end faces and fitted in said member, a plurality of holes .extending axially therethrough and throughthe end faces, said holes each having a double conical form providing a volumetric area sufficient to remain open from end to end at all times up to the point where the end faces have'been movedV by compression to approach each other to cause each hole to assume substantially a cylindrical form as the end faces approach the possible limit on such movement.

4. A cushioning device including a, block of rubber having end faces, a plurality of holes extending therethrough and through the end faces, said holes having a looking-glass symmetry on opposite sides of a transverse plane and varying groove encircling the same in spaced relation to said end faces and reducing the mass of rubber at the part so encircled.

5. A cushioning device including a drum, a block of rubber snuglyfitted in the drum, provided With opposing pressure receiving faces and provided on its side with an annular groove facing the drum, and said block also provided withra.

plurality of core holes of a double frusturn form extending therethrough and through the oppos. i

ing faces and grouped about and equidistantly spaced from the axis of the block. I

6. In a cushioning device, a block o'f rubber having a cavity therein providing space into which the rubber may extend when subjected to compressive forces acting on the same, anda body ll the cavity when lthe block has reached a desired state of compression and thus a desired de gree of resistance to the compressive forces.

of liquid in the cavity present in an amount to 7. A cushioning device including a rubber block provided with a plurality of external faces, two of said faces forming parallel pressure receiving faces, said block having a' cavity therein dened at least in part by two frusto-cones havingvtheir smaller e'nds in juxtaposition adjacent the center of' the block and means engaging al1-external parts of the block except the two pressure receiving faces for restraining the block from any out- 8. A cushioning device including a block of rubber provided witha cavity having a wall-inclined at anangle to the direction of action of the compressive forces and a metal ring inset inone end ofthe block, surrounding Vone end of the cavity,

-alld acting t0 resist outward distortion 0f 'the I'llb ber atsad end.

9. A cushioning device including a side wall forming structure having a plunger, a cushioning device for resisting the plunger, said device including a block of rubber snugly fitting in the structure and provided with a cavity and a sleeve `iitted in the rubber block, slidably engaging the inner face ofthe structure and acting to prevent abrasion of the rubber as it shifts on the same.

10. A cushioning device including two pressure elements adapted to approach each other, a block of rubber therebetween for resisting said movement, said block provided with a hole extending therethrough and forming the block also into a ring, said block provided with an internal cavity of variable cross-sectional area along its length, restraining means snugly encircling the block at all times to resist` radially outward distention thereof and rigid means within the cavity for resisting radially inward distention thereof when the pressure elements approach'each other and for limiting the approach of the pressure e1e` ments. l

11. A cushioningdevice including a cylindrical block of rubber having a cavity therein at least a portion of which is of frustum form and provided at opposite ends with pressure receiving faces and a metal element inset in and deiining at ,least a portion of the cylindrical face of the block.

12. In a cushioning device, the combination of two members movable relatively towards each other, a block of rubber therebetween resisting such movement, restraining means tending to resist outward distention of the block when compressed between said members, said block proof rubber lling the space therebetween and at all times tending to resist the approach 0f said members toward each other, means in which the block is fitted at all times engaging the block for substantially its entire distance between the end members and acting to restrain outward bulging of the block substantially throughout its entire length,4 said block provided with a cavity substantially circular in cross section inall operative conditions of the device and initially of greater ldiameter adjacent opposite ends than ata midvlength portion, said cavity outlined by a ilexible wall capable of=being distorted inwardly into the cavity under the compressive action ofsaid'end Z members and acting solely by virtueof inherent resistance of the rubber block to become distorted inwardly to impose resistance to the ap- ,preach of said end members.

14. A cushioning device including a single, one- `piece block of rubber, two end engaging members between which the block is squeezed, means at all times in engagement with all other sides of the lblock for preventing or at least restraining any freedom of outward distention of the block, the

contacting faces of the block and said engaging means being substantially of the same contour and said block provided interiorally with at least one hole of minimum cross sectional area at its midlength and progressively increasing in cross sectional area towards opposite ends thereof when under minimum load and maintaining circular cross sectional areas in all operative positions of 15. A cushioning device including a hollow rubber block. a' plurality o f means each engaging the block and coacting to form a housing at all times completely enclosing said block and acting to re'-A sist any outward distension lof all external surfaces of the block, at least one pair of said means forming pressure elements for squeezing the block therebetween as they approach each other and said block provided with a plurality of openings of hour-glass form with their smallest diameters or necks in the medial transverse plane and conthe block therebetween and cause the rubber to i distend into the hollow space in the block, the perimeter of the block at its opposite ends being bevelled to space the extreme ends of the block vinwardly from the band and thus tend to eliminate the flow of the rubber into the spaces beltween the band and said squeeze means as the rubber block is squeezed.

17. In a cushioning device, the combination of a hollow block of rubber having opposing pressure receiving ends, pressure means acting on at least one of said ends to squeeze the block in the direction of a line of thrust perpendicular to said ends, means snugly encircling the block in all positions of the same and thus resi-sting all outward distortion ofthe block in all directions radially of said pressure receiving ends provided with a plurality of recesses normally oi conical form with their greater cross sectional area at their respective end faces and with their axes parallel to said axes of thrust, and said block having a maximum cross sectional area of material in spaced relation to its pressure receiving ends and decreasing in cross sectional area of material therefrom towards its adjacent end, two pressure members between which the block is squeezed and means snugly encircling at least the pressure receiving ends of the block 'in all operative' positions thereof to resist outward distortions thereof when under the squeeze action of said pressure members.

19. In a cushioning device, the combination of a rubber block defined at opposite ends by parallel pressure receiving faces and adapted to be squeezed by opposing compressive forcesacting on said faces, said block provided at each of said faces with a plurality of conical cavities, each with `its larger end at its respective pressure receiving face, said block having'its maximum cross sectional area of material in a medial plane parallel to said receiving faces and reducing in cross sectional area of material in succeeding parallel planes at least towards one of said faces and ref straining means encircling said ends of least cross sectional area of material to resist any outward distortion of said pressure receiving ends.

20. In a cushioning device, the combination of two pressure creating members arranged to approach each other along an axis of thrust, a block of rubber positioned between said members and at all times tending to resist said approach. said block provided with opposing pressure receiving end surfaces engaged by said members, each end portion of the block having a plurality of cavities therein opening through their adjacent end sur- `faces, the cross sectional area of material in a plane at thesinner end of the cavities in each end being maximum and gradually decreasing therei from in cross sectional area of material in sucsaid line, said block provided with an opening extending coaxialiy with said line of thrust, said opening outlined by an annular wall of rubber of greater cross section of material adjacent its midheight than at opposite ends and providingmeans responsive to the squeeze force from said pressure means for cau-sing solely inward distortion of the rubber towards said line with minimum lradial distortion in a medial plane spaced from and parallel to both ends and progressively increasing in radial distortion from said medial' plane towards both of said ends.

18. In a device of the class described, the combination of a rubber block symmetrical relative 'to an axis of thrust and provided with pressure receiving ends at opposite ends thereof, each of ceeding planes towards the ends of the cavities at said surfaces and restraining means encircling the block at each end in all positions of the adjacent pressure creating member, said means extending therefrom for at least the major portion of the lengths of the associated cavities, 'said restraining means acting to resist outward distortion of the material of least cross section forming the two end portions of the block in all operative positions of the cushioning device.

21. In a cushioning device,'a cylindrical block

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