US3703014A

US3703014A - Tiltable bearing means, especially for bridges

Info

Publication number: US3703014A
Application number: US111854A
Authority: US
Inventors: Waldemar Koester
Original assignee: Koerber AG
Current assignee: Kober AG Glarus; Koerber AG
Priority date: 1971-02-02
Filing date: 1971-02-02
Publication date: 1972-11-21
Anticipated expiration: 1989-11-21

Abstract

This invention relates to bearing means, especially for heavy loads such as bridges. A piston means on which the load bears is held in a cylinder which is also filled with pressure material. The surface of the piston which faces the pressure material has such a shape that the piston height, relative to a central axis, increases from said axis toward the periphery of the piston whereby such pressure material facing surface of the piston may, for example, have a concave shape, a stair-step shape, a hollow cone shape, or any other shape providing the smallest piston height at the location of said axis and a larger piston height at the piston periphery.

Description

United States Patent Koester [54] TILTABLE BEARING MEANS,

ESPECIALLY FOR BRIDGES [72] Inventor: Waldemar Koester, Forsbach, Germany [73] Assignee: Firma Kober AG, Glarus, Switzerland l22| Filed: Feb. 2, 1971 I21] Appl. No: 111,854

[151 3,703,014 [4 1 Nov. 21, 1972 1/1964 Germany ..14/16 Primary Examiner-Nile C. Byers, Jr. Attorney-W. G. Fasse [57] ABSTRACT This invention relates to hearing; means, especially for heavy loads such as bridges. A piston means on which the load bears is held in a cylinder which is also filled with pressure material. The surface of the piston which faces the pressure material has such a shape that the piston height, relative to a central axis, increases from said axis toward the periphery of the piston whereby such pressure material facing surface of the piston may, for example, have a concave shape, a stair-step shape, a hollow cone shape, or any other shape providing the smallest piston height at the location of said axis and a larger piston height at the piston periphery.

22 Claims, 19 Drawing Figures PATENTED W I97? 3. 7 03,014

sum

2 or 3 35 37 FIG. IO FIG. 1 26 37 26 47 4I FIG. I2

INVENTQR. WALDE'MAR KO'STER ATTORNEY PATENTEDN VZ I912 3.703.014

SHEET 3 0F 3 INVENTOR. WALDEMAR KUSTER ATTORNEY TILTABLE BEARING MEANS, ESPECIALLY FOR BRIDGES BACKGROUND OF THE INVENTION The invention relates to tiltable bearing means, more specifically for heavy loads such as bridges or the like whereby the load is effective on a piston which reaches into space confining means preferably having a cylindrical shape and having an outer wall as well as a bot- 1 tom wall to form a pot or pan-shaped space confining means whereby the volume between the bottom of the pan and the piston is filled with a pressure material having elastical or plastic characteristics.

Conventional bridge bearing means are mainly constructed as tilting bearings comprising a point or line supporting contact between the bearing members which are movable relative to each other. These conventional bearing means are made of steel and their main drawback is the large structural height. It was possible only to increase the carrying load of these conventional bearing means by developing of materials having a larger tensile strength as well as a larger Vickers hardness.

Efforts have heretofore been made to produce bridge bearing means having a structural height as small as possible which are more easily to construct and to assemble and which have an improved adaptability for use in connection with modern bridge types. These efforts resulted in the development of the synthetic material bearing for modern bridge. construction whereby preferably elastomeric materials as well as polytetrafluorethylene (PTFE) have been used. Usually bearings made of synthetic material are constructed in the form of areal or surface bearing means in which the structural members to be supported and which are movable relative to each other are carried on discs of synthetic materials. These bearing means of synthetic material have an especially low structural height. In addition these areal synthetic material bearing means permit, to a limited extent, horizontal movement as well as tilting movements in all directions.

Whereas thesynthetic material known as PTFEhas been used in the construction of bridges generally only as a sliding layer for improving the friction coefficients of the bearing means, elastomeric materials in the form of plates of natural or synthetic rubber having the required dimensions have been used for constructing the bearing cushions proper. Such rubber bearings, however, have the disadvantage or drawback that they are not sufficiently corrosion resistant and that they permit relatively large deformations. Thus, it was necessary to use lateral supports for limiting the bulging of the rubber cushions along itslateral surfaces where such rubber bearing means have been employed for bridge bearings. Reference ismade in this connection to German Pat. publication DAS l 233 426. In addition it was necessary to limit the transverse strain of such bearings by using reinforcement inserts having a high tensile strength and extending in parallel to the surfaces subject to the load. Such reinforcement inserts may be provided in the form of steel plates, supporting grids, or similar reinforcement means such as fibers or webs as described in German Pat. publication DAS l 233 000.

A further development of these well-known so-called rubber bearings is disclosed in the so-called pot or pan bearing as described in German Pat. No. l 873. The bearing according to this patent comprises a steel pot into which is inserted a rubber plate which is compressed by the bearing pressure exerted from the cover side of the pot whereby the rubber plate acts just as if it were an enclosed liquid. The bearing is effective in the same manner as a point tilting bearing however with limited tilting movements. It is possible to construct the 0 so-called pot or pan bearings in such a manner that they are effective as sliding bearings by combining the basic pan construction with glide layers preferably made of PTFE which slide or glide on hard chromium plated steel plates. By suitably constructing the socalled pot it is possible to transmit high pressures or rather to support heavy loads without a substantial compression. Furthermore, the pot provides an advantageous possibility of substantially eliminating corrosion effecting influences. However, the so-called pot bearings have the disadvantage that a substantial sealing effort must be made in view of the high pressures which are exerted on the rubber cushion in order to prevent that the rubber may escape between the inner wall of the pot and the cover member which is guided inside thepot.

The danger that rubber may escape from the pot is relatively large because it is not possible to provide a sufficiently close tolerance between the cover member and the cylindrical wall portion of the pot since such close tolerances would hinder the necessary tilting motions of the cover member on the rubber pressure cushion. Besides, the cover member effects horizontal motions relative to the pot whereby the cover member contacts the pot wall on one side of the inner pot wall whereas the gap on the opposite side becomes twice as large as the normal tolerance. In order to seal the gap metal sealing rings have been used which are held underneaththe cover member in a groove of the pressure cushion. However, due to the large pressures or loads which occur in the rubber mat forming the pressure cushion destructions are quite frequent at the sealing rings and at the wall of the so-called pot. In order to avoid the occurrence of forces which cause such destructions, a conventional type of tilting bearing has been provided, in addition to the sealing ring, with a guide ring in the gap between the cover member and the wall of the pot whereby the sealing ring and the guide ring are made ofa material having a small friction lower corner areas of the pot.

OBJECTS OF THE INVENTION The invention aims atachieving the following objects:

To overcome or alleviate the outlined drawbacks, especially to reduce wear and tear by a more. efficient loaddistribution;

To provide bearing means which may be used for heavy loads especially bridges as fixed bearing means as well as for a movable or an expansion bearing means;

To provide a bearing means which may easily be modified to operate as a gliding bearing;

To provide a bearing means for heavy loads which has exceptionally simple structural features and thus is inexpensive to produce;

To provide a bearing means which is capable of controlling or eliminating the sealing problems mentioned above and which have not been satisfactorily overcome heretofore;

To provide bearing means in which the sealing characteristics or sealing forces are increased automatically with increasing loads independently of the instantaneous tilted position of a bearing member relative to another bearing member;

To provide a bearing means in which a piston member is movable within space confining, preferably cylindrical means and wherein the material of the piston member has been selected to have plastically yielding characteristics with a predetermined range and to dimension the piston member relative to the cylindrical member so as to assure the necessary sealing characteristics while simultaneously permitting the mentioned tilting movement;

To provide a bearing means which even after a sealing failure retains substantial bearing characteristics;

And to construct a bearing means which has a low overall structural height.

SUMMARY OF THE INVENTION According to the invention there is provided a tiltable bearing means especially for bridges comprising a piston member movably contained in a space confining member such as a cylinder filled with a pressure material whereby the piston member has a height which increases from its central axis toward its peripheral surface so that its end surface which faces said pressure material in the cylinder has a shaped form whereby the piston member is so dimensioned that its outer surface contacts the inner surface of the cylinder in such a manner that by suitably selecting the shape and/or the material of the piston member as well as of the cylinder member of the piston member is pressed against the inner surface of the cylinder member in a sealing manner by the load of the superstructure.

It has been found that by giving the piston member which reaches into the cylinder or pot member a special shape the piston member will snugly and sealingly contact with its peripheral outer surface the inner surface of the cylinder member under the load of the superstructure because the load exerts'a pressure through the pressure material in the cylinder directly onto the shaped surface of the piston member.

According to preferred embodiments of the invention the shaped lower surface of the piston member which faces the pressure material may have a concave shape, the surface may also have a single br multiple stair-step shape. In yet another embodiment it may have a relatively fiat hollow conical shape. In any of these embodiments the load will exert a pressure through the shaped surface so that the outer surface of the piston member will snugly contact the inner surface of the cylinder member.

BRIEF FIGURE DESCRIPTION In order that the invention may be clearly understood it will now be described, by way of example, with reference to the accompanying drawings, wherein:

FIG. 1 is a partial side view illustrating on a reduced scale and in a schematic manner a bridge structure to show the location of the present bearing means;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a sectional view through one embodiment of a bearing means according to the invention;

FIGS. 4, 5 and 6 illustrate sectional views through different embodiments of the piston member according to the present invention;

FIG. 7 is a sectional view similar to that of FIG. 3 showing the location of the pressure material and a cover member;

FIG. 8 illustrates a modified embodiment of the invention wherein the pressure material fills a specially shaped gap between the cylinder member and the piston member of the present bearing means;

FIG. 9 illustrates an embodiment quite similar to that of FIG. 8 with the modification that the gap is formed between an insert member and the piston member of the bearing means;

FIG. 10 shows an embodiment wherein the bottom of the cylinder means is also formed as a piston member in accordance with the teachings of this invention;

FIG. 11 is an embodiment similar to that of FIG. 10

with the modification that an intermediate bottom is provided between the two piston members;

FIG. 12 illustrates an embodiment wherein the piston member is effective in two cylinder members thus providing a double bearing means;

FIG. 13 shows a modified version of a double bearing means according to the invention;

FIG. 14 illustrates one half of a bearing means according to the invention constructed as a fixed bearing means, the other half of the bearing means is mirror symmetrical to the half shown;

FIG. 15 is an embodiment of the invention illustrating a double bearing means constructed as a slidable or expansion bearing means;

FIG. 16 illustrates a modification in the structure of the piston member;

FIG. 17 shows a modified structure for a double piston member according to the invention;

FIG. 18 illustrates a double bearing means according to the invention constructed to operate as a fixed bearing means whereby the right-hand half of the figure which is mirror symmetrical to the left half shown, has been omitted; and

FIG. 19 is a view similar to that of FIG. 18 with the modification that the bearing means has been constructed as a slidable or expansion bearing means.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 illustrates a bridge side view in a schematic manner. A bridge superstructure l rests on bearing means 2 and 3 which in turn are carried by the supporting structural members 4 of the bridge. The bearing means 2, for example, may be constructed as a fixed bearing means whereas the bearing means 3 may be constructed as a slidable or expansion bearing means as will be explained more fully below.

FIG. 2 is a top view of FIG. 1. It will be appreciated that instead of using bearing means having a diameter which corresponds substantially to the width 5 of the superstructure, it is possible to employ several bearing means having a smaller diameter and arranged in sideby-side relationship.

FIG. 3 illustrates a sectional view through either the

bearing

2 or 3 of FIG. 1. The present bearing means comprise space confining means, for example in the form of a pot or pan 6 having side walls 7 and a bottom wall 8 as well as piston means 9 having an outer peripheral wall 10 and a shaped surface 11 facing inwardly as well as a top surface 12.

The bearing device shown in FIG. 3 has a central axis 13. Within certain limits the piston member 9 is tiltable about the axis 13 as indicated by the double arrow 14. The space 15 which is confined between the pan member 6 and the piston member 9 is filled witha pressure material not indicated in FIG. 3 to provide space for arrows 16 which extend perpendicularly to all surfaces which confine the space 15. Thus, the pressure material exerts a pressure simultaneously in all directions as indicated by the arrows 16 against the inner surfaces of the pan and thus also againstthe inner surfaces of the side walls 7. According to the invention the pan 6 is preferably made of steel while the piston member 9 is made of a material having plastic characteristics within certain ranges. Thus, the piston member 9 may be made of such materials as plastics, for example polyamide, or it may be made of a metal,preferably a non-ferrous or light metal. In any event, the piston material is selected to provide a low friction coefficient relative to the inner surfaces of the side walls 7 and also relative to the pressure material in the space 15. Further the material forthe piston member9 shouldbe self-lubricating. Due to the fact that the material of the piston member 9 may yield in aplastic manner to the forces 16, the invention accomplishes a tight seal between the peripheral surface 10 of the piston member 9 and the inner surface of the side walls 7 of the pan 6. It is an advantage of the invention that the just mentioned sealing is assured even if close tolerances between the piston member 9 and the pan member 6 are not maintained because the plastic characteristics of the piston member in combination with the existence of lateral force components between the piston member and the side walls of the pan permit the piston member to yield sufficiently .for providing such sealing.

FIG. 4 illustrates a modifiedpiston member 17. The shaped inner surface 18 of the piston member l7lhas the form of a relatively flat hollow cone. Here againthe shape of the inner surface 18 will assure the presence of lateral force components which will forceespecially the lower ring portion 19 of the piston member outwardly against the inner surface of the side walls ofthe pan member.

FIG. 5 illustrates another embodiment of a piston member 20 having an inner surface 21 in the form of stair steps 22. FIG 6 is quite similar to that of FIG. 5 except that the piston member 23 comprises an inner surface 24 with but one stair step 25.

FIG. 7 is an embodiment quite similar to that of FIG. 1. Accordingly the same reference numerals are employed for the same elements. However, the space 15 between the shaped lower surface of the piston member 9 and the inner surface of the pan '6 is shown to be filled with a pressure material 26 and the piston member 9 is held in a cover plate 27 which functions as a load receiving means to which the load is applied as indicated by the arrow 28 whereby the pressure forces are exerted as explained with reference to FIG. 3 whereby the peripheral portions 29 of the piston member 9 are pressed against the inner surfaces of the side walls 7 of the cylinder member 6. The load receiving cover plate 27 functions as an interconnecting member between the bearing means proper and the supportingelements of the superstructure. It is preferable to provide a rough tolerance between the cover plate 27 and the piston member 9 so that the latter may slide in the cover plate when it expands under the pressure of the load. In orderto use the bearing means according to FIG. 7 as a gliding and/or tilting bearing means, a gliding facilitating layer 30, for example of PTFE, may be inserted in a respective recess in the top surfaceofthe coverplate 27. The layer 30 would glide relative to a corresponding layer attached to the supporting members of the superstructure not shown in FIG. 17. However, if the layer 30 and its recess are omitted, the bearing means may be used as a so-called fixed bearing means.

Referring to FIG. 8 there is: shown a modified cylinder space confining means 31 having a bottom configuration 32 which is also shaped rather than plane, in orderto conform to the shaped surface 11 of theipiston member 9. Since in the shown embodiment the downwardly facing surface 11 of the piston member is concave, the'bottom 32 of the cylinder means 31 has a convex shape whereby a gap of uniform width along .the entire surface 11.is provided between the piston member9 and the bottom 32. The gap is filled with a pressure material 26 such as rubber. This embodiment ment ofFIG. 8, which also applies to the embodiment of FIG. 9stobe described shortly, is seen in the fact that the bearing will continue to function even after the pressure material 26 should have escaped, for example under catastrophic emergency conditions. The continuing function of the bearing means is assured by the matching between the surface 11 and the upwardly facing-surface of thebottom 32 which provides a surface contact enabling the two bearing members to cooperate in the manner of a calotte bearing or in the mannerof a point tilting bearing so that the bearing may serve as an emergency bearing. The just described advantage may further be improved by replacing the uniform width of the gap by agap which increases from the central axis 13 toward the periphery of the piston member as will be explained in more detail below with reference to FIG. 1 18.

The embodiment of FIG.'9 is quite similar to that of :FIG. 8. Accordingly the just described advantages .apply aswell to FIG. 9. However, the bottom 33 of the cylinder meansis formed by a convex insert 34 which may, :forexample, also be made of steel just as the cylinder means itself.

Another embodiment of the invention provides the bottom of the cylinder means in the form of a second piston member 35. This feature is shown in FIG. 10 wherein the cylinder means comprise a ring member 36 and to which the piston member 9 fits as described above and the bottom of which is formed by the second piston member 35. The downwardly facing shaped surface 11 of piston member 9 faces an upwardly facing surface 37 of the piston member 35. Both shaped surfaces may, for example, as shown have a concave surface configuration and the space between the two concave surfaces is filled with the pressure material 26, for example rubber. In this embodiment the ring member 36 is enabled to perform a floating up and down movement relative to both

piston members

9 and 35 which, between mirror

symmetrical surfaces

11 and 37, for a biconvex pressure space filled with the pressure material 26. The embodiment of FIG. 10 permits an especially uniform application of the load to the cylinder ring 36 by the pressure applied to the piston member 9. In practice stop means will be provided for limiting the axial up and down movement of the cylinder ring 36 and/or of the two

piston members

9 and 35. Such limiting means are not shown for simplicitys sake. Load receiving or supporting means may also be provided for the

piston members

9 and 35.

The above-mentioned floating axial up and down movement of the cylinder ring 36 is substantially prevented in the embodiment of FIG. 11 wherein an intermediate bottom 38 is connected to the cylinder ring 36 for example by a weldment 39. The intermediate bottom 38 divides the biconvex pressure space into two substantially equal portions each of which is filled with the pressure material 26. Thus, the pressure material supports the cylinder ring 36 through the intermediate bottom 38. Moreover, the cylinder ring 36 is held in a centered position relative to the

piston members

9 and 35. Although the illustrated centered or symmetrical position of the intermediate bottom and the ring relative to the piston members is preferable, the embodiment of FIG. 11 makes it possible to adjust the position of the cylinder ring 36 relative to the piston members 9 a and 35 by appropriately positioning the intermediate bottom 38 closer to one or the other end of the cylinder ring 36 prior to rigidly interconnecting the ring 36 and the intermediate bottom 38.

The embodiments so far described employ a single space confining means in the form of a pan or pot whereby the pan may be formed for example by a ring and a second piston member forming the bottom of the pan. However, the invention may also be embodied by employing two pans for the space confining means and inserting a double piston member into both cylinder means which is guided along its peripheral surface and which has top and bottom surfaces shaped in a mirror symmetrical fashion relative to each other. Each piston end reaches into one of said pans whereby both pans are independent of each other. Thus, two pressure spaces are formed both of which are filled with a pressure material and a gap is generally provided between the two pans that will now be described in more detail. FIG. 12 embodies the just mentioned features, namely an upper pot 40 and a lower pot 41 each having

respective side walls

42 and 43 facing each other. A gap 44 is provided between the two

pans

40 and 41 to permit axial up and down movement. The gap 44 is sealed by a double cylinder 45 having a biconcave shape with an upwardly facing concave surface 46 and a downwardly facing concave surface 47 to form two pressure spaces each of which is filled with a pressure material 26, for example rubber. The bearing means of FIG. 12 are especially suited for a gliding and tilting bearing because a gliding layer (not shown) may be directly inserted into the top surface of the top pan 40 whereby an additional connecting member between the glide bearing and the tilting bearing has been obviated.

The embodiment of FIG. 13 is similar to that of FIG. 12 in that the double piston 45 is also effective in two separate space confining means. However, these means comprise two

separate rings

48 and 49. The ring 48 is closed intermediate its ends by a plate 50 which may be, for example, welded into the ring. Similarly, the ring 49 is closed intermediate its ends by a bottom plate 51. The connection between the plates 50 and 51 with their

respective rings

48 and 49 is suitably such that the members are subject to a tension force. This may be accomplished, for example, by shrinking the ring onto its respective plate.

The embodiment of FIG. 13 is especially suitable for use as a fixed bearing means because the spaces 52 and 53 above and below the respective plates 50 and 51 contribute to a form locking connection between the bearing means and the concrete structure whereby the

rings

48 and 49 with their respective plates 50 and 51 form simultaneously parts of the bearing proper as well as of the supporting structure. The structural details of the double piston 45 shown in FIGS. 12 and 13 may be the same as those described with reference to the other figures especially with regard to the dimensioning and to the selection of plastically yielding materials. The double piston embodiment of the invention has the special advantage that it makes possible a substantially play free adjustment of the two

pans

40 and 41 or of the

rings

48 and 49 relative to each other whereby the tilting movement is distributed on two pans rather than on one whereby all occuring bearing movements are taken up in a wear and tear reducing manner.

A further advantage of the just described embodi-' ment is seen in that the double piston is held precisely in a center position between the two cylinder means due to the fact that the piston is supported at both ends in the pressure material 26. Moreover, the arrangement of the two cylinder means makes possible an especially simple and advantageous interconnection between the bearing proper and the supporting means of the structure. This will be described in more detail below.

FIG. 14 illustrates the left-hand half of a bearing such as shown in FIG. 12. The right-hand half of the bearing of FIG. 14 is mirror symmetrical relative to the center axis 13. The bearing of FIG. 14 is constructed as a socalled fixed bearing wherein the lower cylinder member 41 rests on a base plate 54 which in turn is rigidly attached to the concrete of the supporting structure 4. The upper cylinder member 40 rests against a top plate 55 which is rigidly connected to the concrete of the superstructure 1, for example, by means of steel straps 56 which may be welded to the top plate 55. Both

cylinders

40 and 41 are restrained against a radial, horizontal movement by means of

rings

57, 58 attached to the top plate 55 and to the bottom plate 54 respectively. Ring 57 surrounds the cylinder member 40,

whereas the ring 58 surrounds the cylinder member 41. Thus, a horizontal movement of the superstructure 1 is transmitted to the base plate 54 by means of

rings

57, 58, the

cylinders

40 and 41, as well as the double piston 45 The bearing means according to FIG. are similar to that of FIG. 14, however, FIG. 15 illustrates a gliding and tilting bearing means whereas FIG. 14 shows a simultaneously serves as a top cover, is provided with a glide surface 60 which rests on the glide plate 59 whereby the top plate 55 is horizontally movable relative to the glide plate 59 thus providing a glide bearing which in combination with the double piston 45. is also a tilting bearing. The movement of the top plate 55 relative to the remaining bearing element is indicated by the double arrow 61. The glide surface 60 may be provided in the form of a chrome plating or in the form of a sheet metal preferably of austenitic steel.

FIGS. 16 and17 illustrate bearing means according to the invention comprising a special construction of the circumferential surface of the piston means. Thus,

in FIG. 16 the piston 62 has an upper portion63 of reduced diameter. A larger diameter lower portion forms a peripheral rim 64 which bears against the inner surface of the side walls 7 of the cylinder means 6 whereby the sealing characteristics are even better because the outwardly extending rim portion yields more easily to the pressures exerted on it through the pressure material 26.

While the embodiment of FIG. 16 is suitable for a single cylinder arrangement, the embodiment of FIG. 17 illustrates a double piston 65 also having a portion 66 of reduced diameter whereby an upper peripheral rim 67 as well as a lower peripheral rim 68 are formed which rims 67, 68 bear against the inner surfaces of the side walls of respective cylinder means 69 and70. The embodiments of FIGS. 16 and 17 have the advantage that especially large tolerances between the piston and the cylinder means are possible because the

peripheral rims

64, 67 and 68 function in the manner of sealing lips.

FIGS. 18 and 19 illustrate details of means for facilitating the interconnection between the bearing means proper and the supporting structure on the one hand, as well as the bearing means and the superstructure on the other hand. Thus in FIG. 18 the cylinder means 71 and 72 are provided with

surface increasing corrugations

73 and 74 which face toward the superstructure l and the supporting structure 4 respectively. The corrugations may be replaced by other surface increasing means, for example, protrusions or recesses which extend at an angle or perpendicularly relative to the horizontal.

The cylinders 71 and 72 of FIG. 18 are provided with

inserts

75 and 76 and a double piston 77 as inserted with its shaped

surfaces

78 and 79 into the upper cylinder 71 and into the lower cylinder 72 respectively. The inserts and 76 have surfaces 80 and 81 shaped for. cooperation with the

surfaces

78, 79 of the double piston 77 in such a manner that

gaps

82 and 83 are formed which have a smaller width 84 near the center axis 13 and a larger width 85' near the periphery of the double piston 77. This feature increases the above mentioned capability of the present hearings to operate as an emergency bearing in case the pressure material 26 should escape under extremely adverse operating conditions. The increased height near the periphery of the piston 77 may be accomplished. by providing inserts having asmaller diameter than the diameter of the piston so that the inserts do not extend completely to the side walls of the respective cylinder.

The above-mentioned surface increasing means such as the

corrugations

73, 74 are rigidly connected in a form locking manner to interconnecting section members 86-which conform to the surface configuration of the cylinder means. The interconnecting members 86 may be made, for example, of a synthetic material which isreinforced by means of glass fibers. The just described embodiment is especially suitable for constructing all bearing members, including the cylinders, of synthetic material. Moreover, by means of said con necting members 68 it is possible to interconnect the bearing members proper with the supporting structure 4. This may be accomplished by a rim 87 which may be snapped into a respective recess in the supporting structure.

The above-mentioned gap 44 between the two cylinder members is coveredby a sealing strip 88. For example, the sealing strip 88 may, be provided with beaded edges 89 which snap into respective grooves 90 inthe outer surface of the cylinder side walls adjacent to the gap 44- whereby the gap is closed and sealed. This feature of the invention has the advantage that the bearing isprotected against corrosion as well as against the entering of dirt and water into the bearing proper.

Whereas FIG. 18 illustrates a fixed bearings means, FIG. 19 shows a partial view of a bearing means permitting a gliding. function as well as a tilting function, for example, in response to expansion of the superstructure. The cylinder 91 is provided with an insert 92 which in cooperation with the double piston 93 provides a gap 94 filled with the pressure material 26. A glide plate 95 is inserted into a respective recess in the upper surface of the cylinder 91. The glide plate 95 may be made for example of PTFE. The superstructure 1 rests on the glide plate 95 through a further glide plate 96, for example made of polyacetal which is rigidly connected to the interconnection member 97 which in turn is embedded in the superstructure. The cooperating

glide plates

95 and 96 permit a relative horizontal movement between the superstructure 1 and the bearing cylinder 91. i

It is to be understood that the invention is not limited to the specific example embodiments described above. For example, the described elements may be combined in various manners. Thus, the cylinder means may comprise an integral structure of the bottom and side surfaces or the cylinders may be constructed from several parts interconnected by welding or casting or by a shrinking method whereby the outer side walls of the cylinder are shrunk onto the plate which forms the bottom of the cylinder.

Even the cylinder member of a bearing may surround the piston member under a pre-applied stress or tension which may be accomplished by correspondingly dimensioning the piston and the cylinder member relative to each other.

Moreover, the invention is not limited to the circular shape of the bearing members as illustrated. The circular shape has merely been used as a preferred embodiment and for the sake of simple illustration. Thus, the invention encompasses bearing members which have a different horizontal cross-section or shape, for example, a quadratic, or rectangular, or polygonal shape. In this connection, it is an important feature of the invention to provide the piston means with mirror symmetrical end faces which either face in opposite directions as shown, for example in FIGS. 4, and 6 and in FIGS. 12 and 13; or which face each other, for instance as in FIGS. and 11.

In view of the foregoing it is to be understood that the invention comprises all modifications and equivalents within the scope of the appended claims.

Whatl claim is:

1. In a tiltable bearing for supporting a load on a substructure wherein piston means having a central axis,

an outer wall and two end faces opposite each other are I movably supported in space confining means, and wherein a yielding pressure material is located in said space confining means between said piston means and part of said space confining means, the improvement comprising upper and lower space confining pan means, said piston means having a height which increases from said central axis toward said outer wall of the piston means so that both end faces of said piston means have a shaped surface facing said pressure material in its respective pan means, whereby said end faces are substantially mirror-symmetrical relative to each other, said outer wall of the piston means and the space confining means being dimensioned relative to each other so that the outer wall of the piston means is movably inserted into the upper and lower pan means, said piston means closing an upper and a lower chamber between each piston end face and the respective pan means, said piston means being capable of yielding, whereby a load applied to the bearing presses the outer piston wall laterally outwardly against both space confining pan means in a sealing manner to confine said pressure material in said upper and lower chambers.

2. The tiltable bearing according to claim 1, wherein said outer wall of the piston means has a groove extending all around the piston means, which groove facilitates the lateral, outward pressing of the outer piston wall and thus the sealing.

3. The tiltable bearing according to claim 1, wherein said space confining means are made of steel.

4. The tiltable bearing according to claim 1, wherein said shaped surfaces of the piston means facing said pressure material are concave.

5. The tiltable bearing according to claim 1, wherein said shaped surfaces of the piston means facing said pressure material have a stair step configuration.

6. The tiltable bearing according to claim 1, wherein said shaped surfaces of the piston means facing said pressure material have a conical configuration.

7. The tiltable bearing according to claim 1, wherein said space confining upper and lower pan means each have a substantially upright side wall and a bottom wall, said bottom wall having a configuration corresponding to the shaped surface of said piston means whereby spacings of uniform height are provided between said bottom wall and said shaped surfaces of the piston means facing said pressure material, said uniform height extending over the entire diameter of the piston means.

8. The tiltable bearing according to claim 7, further comprising an insert in said confining means, said insert resting on said bottom wall and having a shaped upper surface for providing said spacing.

9. The tiltable bearing according to claim 1, wherein said space confining means have substantially upright side wall means and a bottom wall, said bottom wall facing said shaped surface of the piston means having a configuration so that a spacing is provided between the piston means and the bottom wall for said pressure material, said spacing having a height which is larger in portions adjacent to said outer wall of the piston means than in portions closer to said central axis.

10. The tiltable bearing according to claim 1, wherein said upper and lower pan means are spaced from each other to form a gap between the upper and lower pan means, said outer wall of the piston means bridging said gap.

11. The tiltable bearing according to claim 10, further comprising a flexible sealing sleeve which surrounds part of said upper pan means and part of said lower pan means to cover said gap therebetween.

12. The tiltable bearing according to claim 11, wherein said flexible sealing sleeve has an upper edge with means for securing the upper edge to the upper pan means and a lower edge also with means for securing the lower edge to the lower pan means.

13. The tiltable bearing according to claim 7, wherein said upright side walls of the upper and lower pan means and the diameter of the piston means are dimensioned relative to each other so that the side walls exert a bias force on the piston means.

14. The tiltable bearing according to claim 7, wherein said substantially upright side wall and said bottom wall of each pan means are formed as an integral structure.

15. The tiltable bearing according to claim 1, wherein said piston means comprise peripheral edges between the outer wall and each of said end faces, a portion of said outer wall having a reduced piston diameter to provide a circumferential groove in the outer wall between said peripheral edges, and sealing lip means forming part of at least one of said peripheral edges, said sealing lip means contacting said space confining means.

16. The tiltable bearing according to claim 1, wherein said material of the piston means is a synthetic material such as a polyamide.

17. The tiltable bearing according to claim 1, wherein said material of the piston means is a non-ferrous metal.

18. The tiltable bearing according to claim 1, wherein said material of the piston means is a light metal.

19. The tiltable bearing according to claim 1, wherein said space confining pan means comprise a corrugated outer surface for bonding the lower space confining pan means to said substructure and the upper space confining pan means to the supported load.

20. The tiltable bearing according to claim 1, wherein said space confining means are made of a synthetic material, such as fiberglass.

21. A tiltable bearing for supporting a load on a substructure comprising space confining means for containing a pressure material therein, said space confining means including an outer ring, a first piston member inserted in said ring to close one end of the ring, and a second piston member inserted in said ring to close its other end, said piston members having shaped end faces facing each other and said pressure material, said end faces having mirror-symmetrical surfaces and a spacing between said shaped faces which, due to the mirror-symmetrical shape of the end faces, decreases from a central axis of said piston members toward their periphery, said piston members and said ring being dimensioned relative to each other so that in combination with said shaped end faces the load presses the piston members into sealing contact with said ring.

22. The tiltable bearing according to claim 21, wherein said ring comprises a bottom plate located substantially intermediate said shaped end faces and rigidly connected to the ring.

- UNITED STATES PATENT OFFICE v CERTIFICATE OF CORRECTION Patent No. 3 703 014 v Dated Ngxgmbgr z 1925 Inventor(s) WALDEMAR KOESTER It is certified that error appears in the above-identifiedipatent and that said Letters Patentare hereby corrected as shown below:

On the cover sheet insert [30] FOREIGN PRIORITY DATA February 11, 1970, German ..P 20 06 160.3-25

Signed and sealed this 8th day. of May 1973.

(SEAL Attest:

EDWARD M.PLETCHER,JR. ROBERT GOTTSCH ALK Attesting Officer Commissioner of Patents FORM PC3-1050 (10-69) USCOMM-DC 60876-P59 V U.S GOVERNMENT PRINTING OFFIICE: I969 0-366-334,

Claims

1. In a tiltable bearing for supporting a load on a substructure wherein piston means having a central axis, an outer wall and two end faces opposite each other are movably supported in space confining means, and wherein a yielding pressure material is located in said space confining means between said piston means and part of said space confining means, the improvement compriSing upper and lower space confining pan means, said piston means having a height which increases from said central axis toward said outer wall of the piston means so that both end faces of said piston means have a shaped surface facing said pressure material in its respective pan means, whereby said end faces are substantially mirror-symmetrical relative to each other, said outer wall of the piston means and the space confining means being dimensioned relative to each other so that the outer wall of the piston means is movably inserted into the upper and lower pan means, said piston means closing an upper and a lower chamber between each piston end face and the respective pan means, said piston means being capable of yielding, whereby a load applied to the bearing presses the outer piston wall laterally outwardly against both space confining pan means in a sealing manner to confine said pressure material in said upper and lower chambers.