CA1178123A - Railway truck bolster friction assembly - Google Patents
Railway truck bolster friction assemblyInfo
- Publication number
- CA1178123A CA1178123A CA000398614A CA398614A CA1178123A CA 1178123 A CA1178123 A CA 1178123A CA 000398614 A CA000398614 A CA 000398614A CA 398614 A CA398614 A CA 398614A CA 1178123 A CA1178123 A CA 1178123A
- Authority
- CA
- Canada
- Prior art keywords
- rigid
- friction assembly
- friction
- bolster
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61F—RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES
- B61F5/00—Constructional details of bogies; Connections between bogies and vehicle underframes; Arrangements or devices for adjusting or allowing self-adjustment of wheel axles or bogies when rounding curves
- B61F5/02—Arrangements permitting limited transverse relative movements between vehicle underframe or bolster and bogie; Connections between underframes and bogies
- B61F5/04—Bolster supports or mountings
- B61F5/12—Bolster supports or mountings incorporating dampers
- B61F5/122—Bolster supports or mountings incorporating dampers with friction surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61F—RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES
- B61F5/00—Constructional details of bogies; Connections between bogies and vehicle underframes; Arrangements or devices for adjusting or allowing self-adjustment of wheel axles or bogies when rounding curves
- B61F5/02—Arrangements permitting limited transverse relative movements between vehicle underframe or bolster and bogie; Connections between underframes and bogies
- B61F5/04—Bolster supports or mountings
- B61F5/12—Bolster supports or mountings incorporating dampers
- B61F5/125—Bolster supports or mountings incorporating dampers with rubber elements
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Springs (AREA)
- Vibration Prevention Devices (AREA)
Abstract
RAILWAY TRUCK BOLSTER FRICTION ASSEMBLY
Abstract of the Disclosure A railway freight truck bolster friction assembly and more particularly improved friction assemblies of metallic-faced elastomeric material which are adapted to be captively retained intermediate an axial end portion of a bolster member and an adjacent side frame.
Abstract of the Disclosure A railway freight truck bolster friction assembly and more particularly improved friction assemblies of metallic-faced elastomeric material which are adapted to be captively retained intermediate an axial end portion of a bolster member and an adjacent side frame.
Description
RAILW~Y TRUCK BOLSTF,R FRICTION ASSEMBLY
.
A railway freight truck bolster friction assembly and more particularly improved friction assemblies of metallic-iaced elastomeric material which are adapted to be captively retained intermediate an axial end portion of a bolster member and an adjacent side frame member.
Many modern three-piece railway freight car trucks use rigid wedge-shaped friction members intermediate an axial end portion of the bolster member and an adjacent side frame. These friction members provide the fit-up between the bolster and the 1~ side frame columns and serve to snub or damp the freight car suspension.
In the normal travel of railway cars over a railbed, various differences in the surface profile of the laterally spaced tracks resulting from rail joints and superelevation of the outside track on curves, gives rise to a tendency of resonant swaying and - bouncing of the car body. In modern cars with heavy load capacity and a relatively high center of gravity, the -Eorces and weight shift of the car resulting from track surface variations becomes so large at times that a variety oE efEects may develop such as:
1. Complete unloading of the wheels on one side of the truck to the extent of lifting the unloaded wheels off the rail with a high potential of derailments;
.
A railway freight truck bolster friction assembly and more particularly improved friction assemblies of metallic-iaced elastomeric material which are adapted to be captively retained intermediate an axial end portion of a bolster member and an adjacent side frame member.
Many modern three-piece railway freight car trucks use rigid wedge-shaped friction members intermediate an axial end portion of the bolster member and an adjacent side frame. These friction members provide the fit-up between the bolster and the 1~ side frame columns and serve to snub or damp the freight car suspension.
In the normal travel of railway cars over a railbed, various differences in the surface profile of the laterally spaced tracks resulting from rail joints and superelevation of the outside track on curves, gives rise to a tendency of resonant swaying and - bouncing of the car body. In modern cars with heavy load capacity and a relatively high center of gravity, the -Eorces and weight shift of the car resulting from track surface variations becomes so large at times that a variety oE efEects may develop such as:
1. Complete unloading of the wheels on one side of the truck to the extent of lifting the unloaded wheels off the rail with a high potential of derailments;
2. The imposition of extreme stresses on the car body and truck members; and
3. Cumulative damage and misalignment of track, ties and roadbeds through pounding action.
The need for adequate damping of railway vehicle suspensions has been recognized and to a certain extent alleviated by independent means. Specifically, as mentioned hereinabove, rigid friction members, for example as illustrated in U. S. Patent No. 3,461,815 are generally utilized to dampen or snub the rocking motion by frictional resistance developed between the rigid friction members and the side frame column guides. In addition to the friction members, highly successful hydraulic snubbers, such as shown in U. S. Patent Nos. 4,004,525 and 3,868,912, which are vertically disposed in a spring group, have been developed and provide an even more effective means of snubbing the freight car swaying and bounce.
The utilization of rigid frict:ion members for swaying has been shown to be defective in several areas. For example: the steel-on-steel frictional engagement between the rigid friction member and the side ~rame column guide wear plate results in a "stick-slip" friction action which produces poor ride quality.
Furthermore, with an empty car the transmissability of the "stick-slip" ~riction can result in an excitation or coupling with any or all of the natural frequencies of the railway car components; and the "stick-slip" friction action results in an impacting type start and stop movement of the bolster with respect to the side frames thus leading to potential deleterious structural effects. Further-more, the friction forces on the mating faces of the rigid friction member with respect to the side frame column guide and bolster pockets may reswlt in a requirement for freqwent replacement of components and/or a renewal of wear surfaces. Still further, with the higher frlction forces of some rigid friction members, the railway trucks occasionally have a tendency to seize in a random lozenged angle ~i.e., truck going out of square and the wheel flanges take an acute angle with respect to the guiding rail) thereby increasing unsymmetrical wheel flange and/or tread wear.
The above-mentioned problems have been recognized by the Applicant and overcome, or in the least, greatly alleviated in his invention described in United States Patent No. ~,230,0~7 and which is assigned to the same assignee as is this invention. In this Patent, an elastomeric friction member is provided which de-forms initially before slipping with respect to the side frame column guide wear plate. Further, (just as a pencil eraser drawn across a rigid surface will initially de:Eorm, thereafter have portions slip while other mating portions deform and thereafter slip in its entirety) portio~s of the surface o~ the elastomeric friction member will slip while other portions will initially deform.
Thus, the transition of the elastomeric fric-tion member from rest to movement will be smooth and controlled. With an elastomer, such as urethane, there initially occurs motion wi.thout friction through the deformation of the elastomer and then the friction breaks for a very smooth transition. Furthermore, the relatively soft inter-face of the elastomeric friction member with respect to the rigid mating surfaces results in substantially less wear and failure due to loosening of column wear plates and of adjacent components and surfaces. Still further, the tendency to freeze in a lozenged :~7~
attitude is substantially reduced with elastomeric friction members because of the characteristic shear flexibility of elas-tomers.
Thus, by using elastomeric friction members, control of the various loaded and empty railway freight car motion modes is much superior than with the rigid friction members utilized hereto-fore. Still further, if desired, the hydraulic snubbers, which have been found tobe operative to furnish more linear and optimum damping may be utilized as substantially the sole snubbing means and the elastomeri~ friction member will then serve the primary purpose of maintaining the bolster to side frame fit-up relationship.
In this latter instance, the force levels of the friction member with respect to t,he side frame column can be reduced to more optimum friction levels along with more optimum shear deformation constants.
The elastomeric friction members of United States Patent No. 4,230,047 also offer a controlled lateral restraint ~etween the car body and truck. This controlled lateral restraint tends to increase the threshold primary hunting speed of railway vehicles.
Hunting in railway vehicles is the unstable cyclic yawing ' o trucks and the resultant lateral oscillation of the railway car vehicle and is of particular significance when the car is traveling in an empty condition at relatively high speeds; for example, in excess of 40 mi'Les per hour. The lateral track irregularities com~ined with conventional coned wheel configurations result in one side of the wheel set moving ahead of the other which in turn ~ .~ ~
results in the flanges of the wheels striking and rubbing against the ralls first on one side and then on the other thereby causing undesirable lateral body oscillations and excessive truck component and rail wear. As the wheel treads and flanges wear, ~he tread conicity becomes more severe and the flange-rail clearance becomes larger thereby resulting in even greatPr excursions of the wheel sets during hunting and hence a more severe response occurs at an even lower speed. The lateral excursions can become effectively severe to possibly result in derailments.
The inclusion of the elastomeric friction member, as illustrated in U. S. Patent No. 4,230,047, provides a controlled lateral constraint by increasing the lateral spring constant. The lateral spring constant of the elastomer is added to ~he lateral spring constant of -the spring group t thus increasing the threshold hunting speed in much the same manner as the elastomeric bearing blocks of the side bearing in Applicant's United States Patent No. 4,080,016. For example, the resonance frequency due to hunting with rigid friction members may be l-~ to 2 hertz; however, the inclusion of the elastomeric friction member of Applicant's U. S.
Patent No. 4,230,047 may drive this resonant frequency to 2-~ to 3 hertæ, or even higher. Thus, in some instances it may be possible to adequately control hunting by the inclusion of such elastomeric friction members without the necessity of having elastomeric bearing blocks being disposed within the side bearings. In the least, the lateral spring constant provided by such elastomeric friction members will permit a wider range of choices as to the composition of the side bearing elastomeric bearing blocks.
The elastomeric friction elements, including wedge-shaped elements described in U.S. Patent NoO 4,230r047f have proved to be a significant advance over the prior art friction elements;
however, in certain instances~ the lateral constraint qualities of such friction elements are subject ~o limitations. For example, under circumstances of relatively large lateral excursions of the bolster with respect to the side frames and where the friction element is disposed in a manner that there is no lateral constraint adjacent the transverse sides thereof, there may be a period after friction is broken between the wedge and bearing surface therefor, of substantial lateral movement. This movement of the wedge can result in undesirable impact and wear at the bolster gib particularly ... ...
in rocking loaded cars as well as in hunting empty cars.
In recognition of the limitations of U.S. Patent No.
The need for adequate damping of railway vehicle suspensions has been recognized and to a certain extent alleviated by independent means. Specifically, as mentioned hereinabove, rigid friction members, for example as illustrated in U. S. Patent No. 3,461,815 are generally utilized to dampen or snub the rocking motion by frictional resistance developed between the rigid friction members and the side frame column guides. In addition to the friction members, highly successful hydraulic snubbers, such as shown in U. S. Patent Nos. 4,004,525 and 3,868,912, which are vertically disposed in a spring group, have been developed and provide an even more effective means of snubbing the freight car swaying and bounce.
The utilization of rigid frict:ion members for swaying has been shown to be defective in several areas. For example: the steel-on-steel frictional engagement between the rigid friction member and the side ~rame column guide wear plate results in a "stick-slip" friction action which produces poor ride quality.
Furthermore, with an empty car the transmissability of the "stick-slip" ~riction can result in an excitation or coupling with any or all of the natural frequencies of the railway car components; and the "stick-slip" friction action results in an impacting type start and stop movement of the bolster with respect to the side frames thus leading to potential deleterious structural effects. Further-more, the friction forces on the mating faces of the rigid friction member with respect to the side frame column guide and bolster pockets may reswlt in a requirement for freqwent replacement of components and/or a renewal of wear surfaces. Still further, with the higher frlction forces of some rigid friction members, the railway trucks occasionally have a tendency to seize in a random lozenged angle ~i.e., truck going out of square and the wheel flanges take an acute angle with respect to the guiding rail) thereby increasing unsymmetrical wheel flange and/or tread wear.
The above-mentioned problems have been recognized by the Applicant and overcome, or in the least, greatly alleviated in his invention described in United States Patent No. ~,230,0~7 and which is assigned to the same assignee as is this invention. In this Patent, an elastomeric friction member is provided which de-forms initially before slipping with respect to the side frame column guide wear plate. Further, (just as a pencil eraser drawn across a rigid surface will initially de:Eorm, thereafter have portions slip while other mating portions deform and thereafter slip in its entirety) portio~s of the surface o~ the elastomeric friction member will slip while other portions will initially deform.
Thus, the transition of the elastomeric fric-tion member from rest to movement will be smooth and controlled. With an elastomer, such as urethane, there initially occurs motion wi.thout friction through the deformation of the elastomer and then the friction breaks for a very smooth transition. Furthermore, the relatively soft inter-face of the elastomeric friction member with respect to the rigid mating surfaces results in substantially less wear and failure due to loosening of column wear plates and of adjacent components and surfaces. Still further, the tendency to freeze in a lozenged :~7~
attitude is substantially reduced with elastomeric friction members because of the characteristic shear flexibility of elas-tomers.
Thus, by using elastomeric friction members, control of the various loaded and empty railway freight car motion modes is much superior than with the rigid friction members utilized hereto-fore. Still further, if desired, the hydraulic snubbers, which have been found tobe operative to furnish more linear and optimum damping may be utilized as substantially the sole snubbing means and the elastomeri~ friction member will then serve the primary purpose of maintaining the bolster to side frame fit-up relationship.
In this latter instance, the force levels of the friction member with respect to t,he side frame column can be reduced to more optimum friction levels along with more optimum shear deformation constants.
The elastomeric friction members of United States Patent No. 4,230,047 also offer a controlled lateral restraint ~etween the car body and truck. This controlled lateral restraint tends to increase the threshold primary hunting speed of railway vehicles.
Hunting in railway vehicles is the unstable cyclic yawing ' o trucks and the resultant lateral oscillation of the railway car vehicle and is of particular significance when the car is traveling in an empty condition at relatively high speeds; for example, in excess of 40 mi'Les per hour. The lateral track irregularities com~ined with conventional coned wheel configurations result in one side of the wheel set moving ahead of the other which in turn ~ .~ ~
results in the flanges of the wheels striking and rubbing against the ralls first on one side and then on the other thereby causing undesirable lateral body oscillations and excessive truck component and rail wear. As the wheel treads and flanges wear, ~he tread conicity becomes more severe and the flange-rail clearance becomes larger thereby resulting in even greatPr excursions of the wheel sets during hunting and hence a more severe response occurs at an even lower speed. The lateral excursions can become effectively severe to possibly result in derailments.
The inclusion of the elastomeric friction member, as illustrated in U. S. Patent No. 4,230,047, provides a controlled lateral constraint by increasing the lateral spring constant. The lateral spring constant of the elastomer is added to ~he lateral spring constant of -the spring group t thus increasing the threshold hunting speed in much the same manner as the elastomeric bearing blocks of the side bearing in Applicant's United States Patent No. 4,080,016. For example, the resonance frequency due to hunting with rigid friction members may be l-~ to 2 hertz; however, the inclusion of the elastomeric friction member of Applicant's U. S.
Patent No. 4,230,047 may drive this resonant frequency to 2-~ to 3 hertæ, or even higher. Thus, in some instances it may be possible to adequately control hunting by the inclusion of such elastomeric friction members without the necessity of having elastomeric bearing blocks being disposed within the side bearings. In the least, the lateral spring constant provided by such elastomeric friction members will permit a wider range of choices as to the composition of the side bearing elastomeric bearing blocks.
The elastomeric friction elements, including wedge-shaped elements described in U.S. Patent NoO 4,230r047f have proved to be a significant advance over the prior art friction elements;
however, in certain instances~ the lateral constraint qualities of such friction elements are subject ~o limitations. For example, under circumstances of relatively large lateral excursions of the bolster with respect to the side frames and where the friction element is disposed in a manner that there is no lateral constraint adjacent the transverse sides thereof, there may be a period after friction is broken between the wedge and bearing surface therefor, of substantial lateral movement. This movement of the wedge can result in undesirable impact and wear at the bolster gib particularly ... ...
in rocking loaded cars as well as in hunting empty cars.
In recognition of the limitations of U.S. Patent No.
4,230,047, the Applicant in commonly assigned U.S. Patent No.
4,295,429 of October 20, 1981 has provided still a fur~her invention in the area of elastomeric ~riction members which possesses additional advantages of more controlled lateral restraint in substantially all conditions of operations of three~piece railway vehicles. Such advantages are obtained in this latter patent through the use of a pair of laterally adjacent elastomé~ic friction wedge portions which each engage a respective sloping wear plate surface. With such an arrangement, during lateral movement of a side frame with ~L~7~3 ~3 respect to the bols-ter, the lateral force on one of the wedge portions increases while the force on the other wedge portion is reduced. Furthermore, once friction is bro]~en be-tween the resisting wedge portions and the wear plate, the sloping surface of the wear plate permits the lateral sliding of the wedge portion while simul-taneousl~ providing a transverse wedging action to create a controlled resisting force to oppose the external lateral forces. This controlled lateral resisting force increases in proportion to the compressio~
modulus of the material and the sloping of the wear plate.
~urthermore, by providing even more controlled lateral restrai.nt, the invention therein still further increases the range of choices for the composition of side bearing elastomeric beari.ng blocks and additionally increases the circumstances under which elastomeric bear:iing blocks at the side bearing may no longer be required.
The elastomeric friction members described in the above-mentioned U.S~ Patents Nos~ 4,230,047 and 4,295,429 have proved to be significant advances over the art; however, 2~ in certain instances, limitations have been noted. More specifically, the mating surface of the elastomeric friction member is subject to galling, excessive fretting, wear and the like in the event of surface aberrations at the side frame column guide or wear plate interface or because of contaminants intermediate the sd/ -7_ mating surface of the friction member and wear plate. Furthermore~
e~perience has illustrated that to better insure more consistent control by friction member arrangements, the friction member should best be arranged to provide a somewhat uniform pressure at the side frame column guide. However, not all elastomers which rnight be utilized as an elastomeric friction member, have an appropriate composition within all operating parameters to provide such a uniform pressure. Still further, the very nature of the elastomer results in compression at the leading edge of the friction member towards the trailing edge (i.e., shortening the length of the mating face). Such non-uniform compression, which is at a maximum at the leading edge, results in excessive local pressure against the colurnn wear plate and excessive elastomer wear.
The present invention, which includes a thin metal face bonded or otherwise suitably secured to the mating face of the elas~omeric friction member, s~tbstantially maintains all of the advantages described hereinabove with respect to the prior elasto-meric friction members; however, the invention provides the ad-ditional advantages of curing, or in the least, substantially alleviating the above-mentioned limitations. Inasrnuch as the metal face is relatively thin in comparison to the body of the elasto-meric friction member, the friction member of the present invention (because it deforms in response to loading thereto prior to slip-ping~ generally incorporates the advantages of the prior friction wedges; however, it is to be ~mderstood that the slipping at the interface may be somewhat more abrupt than such prior wedges.
Nevertheless, because of the deformation prior to slipping as well as the other advantages resulting Erom the use of an elastomeric friction member (i.e., lateral constraint, hunting control, fit-up and the like), the present invention is significantly superior over the prior art rigid friction wedges.
Accordingly, it is one object of this invention to provide a bolster to side frame elastomeric friction assembly whioh provides smooth transition and dampingcharacteristics as well as having a superior matlng arrangement at the side frame to friction assembly interface.
It is another object of this invention to provide such an elastomeric friction assembly with improved means for insuring a more uniform pressure at the side frame column guide as well as to increase the useful life of the friction assembly.
~hese and other objects and advantages of the present invention will become more readily apparent upon a reading of the following description and drawings in which:
Fig. 1 is an enlarged partial side elevational view of one embodiment of an elastomeric bolster friction wedge assembly of the present invention in operational position on a conventional railway truck assembly;
Fig. 2 is a cross-sectional view of the embodiment illustrated in Fig. 1 as taken on lines 2-2 of Fig. l;
Fig. 3 is a partial side elevational view of another embodiment of an elastomeric bols-ter friction wedge assembly of the present invention in opera~ional position on a conventional railway truck assembly; and Fig. ~ i5 a cross-sectional wiew of the embodiment illustrated in Fig. 3 as taken on lines l~-~ of Fig. 3~
Referring to Figs. 1 and 2 there is illustrated an elastomeric friction assembly 10 of the present invention which is of the type utilized with a standard four-wheel freight car truck of a conventional design (only a portion of the bolster 12 of one of the side frames 1~ being shown) ~or supporting a car body (not shown).
The elastomeric ~riction assembly 10 is disposed within a pocket 16 formed in an axial end portion of the bolster 12. The assembly 10 is of a configuration which is adapted to be inser-ted within the bolster pocket 16 to replace prior art friction wedges (i.e., see U. S. Patent No. 3,461,815)`without the need to alter .
the standard configuration o~ exis-ting bolsters 12 and side fra~,e 14 of conventional freight car trucks.
At this point it is to be noted that the invention herein is primarily directed to an impro~ement over the rigid bolster to side frame riction wedges utilized heretofore and the operation and cooperation of such an improved arrangement with generally well known railway freight car components. Accordingly, other than as is necessary to describe the preferred embodiment of the invention herein with respect to the bolster and side frame relationship, the balance of the elements specified hereinabove need not be described in detail for a full and complete understanding of this invention to those skilled in the art. Furthermore, for purposes of description hereinafter, inner or inwardly and outer or outwardly shall refer respectively to towards and away from the centerplate (not shown) along the longitudinal axis of bolster 12 and upper and lower or upwardly and downwardly shall refer respectively to towards and away from the top of bolster 12 as viewed in the Figs.
Elastomeric friction assembly ]0 comprises: a friction member 18 and a spring follower member 20 which is biased inl~o engagement with member 18 by means of a spring assembly 22 which extends vertically upwardly between an upwardly facing lower seating surface (not shown) o~ the side fra-me 14 and a downwardly facing lower surface 24 of follower member 20. Follower member 20?,~which is formed of a suitable rigid material, such as steel or the like, haæ a generally upwardly extending triangular configuration and includes a downwardly open keeper pocket 26 formed within surface 24 for the captive retention of the upper end portion of spring assembly 22.
Friction members 18 comprise: an outer first portion of elastomeric material, illustrated as a generally rectangular porti,on 28; and an inwardly projecting integrally formed second portion of elastomeric material, shown as formed triangular portion 30i and a metallic sicle frame mating plate 32 which is secured to the outermost generally vertically extending face of portion 28 and which has a generally planer outer surface 3'4 thereof. Mating plate 32 extends along substantially the entire outer face of portion 28 and is secured thereto in any suitable manner, for example by bonding in th,e molding stage or by bolting.
A wear plate 36 having a generally vertically extending planer inner surface 38 is secured to the column guide 40 of each respective adjacent side frarne 14.
~ 3 With a general conEiguration as described above, when friction assembly 10 is biased into operational position thereof by spring assembly 22, the outer vertically extending surface 34 of mating plate 32 will be biased into engagement with the adjacent vertica]ly extending surface 38 of the column guide wear plate 3 and the lower surface 42 of triangular portion 30 will be in engagement with a complementary sloping sur~ace 44 oE follower 20.
Furthermore, the upper sloping surface 46 of triangular portion 30 will be aligned in a common sloping plane wi-th inner sloping sur-face 48 of follower 20 and the aligned surfaces ll~ and 48 will be in continuous engagement with the adjacent inclined surface S0 o~
the bolster pocket 26. Thus, the friction member 18 will be generally confined within the adjacent portions of the boundary surfaces 38, 50 and 44i however, the areas of portion 28 adjacent the upper and lower ends thereof will not be confined thereby allowing spaces for the elastomerîc portions of member 18 to de-form in shear.
At this point it is to be noted, except with respect to inclusion of mating plate 32 and the resultant advantages ofEered thereby, that the elastomeric bolster friction assembly 10 illustrated in Figs. 1 and 2 is virtually identical to the friction assembly illustrated in Fig. 4 of U. S. Patent No. 4,230 ! 047.
Accordingly, for purposes of the description of this invention, it will suffice to generally state that bolster Eriction assembly 10 possesses the advantages of such a prior elastomeric bolster friction assembly, such as:
~8~23 A. Fit-up of the side frame to bolster relationship because of the confined fit offered by the elastomeric portions of member 18;
B. ~bility to vary the pre-load friction forces by varying the spring constant of the spring assembl~ 22 or by varying the "self actuation angle";
C. Providing a smoother transition of the friction member 18 from sta-tlonary to sliding rather than the abrupt "stick-slip" action of prior art rigid friction wedges;
D. Avoiding excessive wear, abrading or gulling of the mating metallic surfaces; and E. Contributing to a controlled bolster to side frame restraint to thus inhibit hunting.
In the event that more detail is desired with respect to the primary operation of the known elastomeric bolster friction assemblies and/or of the advantages specified hereinabove, reference is hereby made to U. S. Patent No. 4,230,047.
Thus, the bolster friction assembly 10 of the present invention achieves the advantages o~ the prior elastomeric fricti.on assemblies but cures, or substantially alleviates, certain limita-tions of such prior assemblies. Specifically, the inclusion of the metallic mating plate 32 results in more consistent operation and a longer life of the friction member 18 by providing a metal to metal interface at the mating faces 34 and 38. Furthermore, the pressure at the faces 34 and 38 will be more consistent and, inasmuch as the leading edge of the elastomer (i.e., either the top or bottom of the ou-termost portion of rectangular portion 28 -].3--depending upon the direction of the force transmitted to assembly 10~ is bonded or otherwise suitably secured to the mating plate 32, any tendency of the elastomeric material at the leading edge of the rectangular portion 28 to curl under is alleviated.
It is to be noted that the -thickness of the mating plate 32 is dimensioned such that the elastomer of portions 18 and 20 is of a suEEicient mass to provide the requisite operational characteristics of an elastomeric bolster friction assembly of the type illustrated in U. S. Patent No. 4,230,047. On balance, the only adverse operational distinction between the ideal described`
in such Patent and the present invention is that during vertical movement of the bolster 12 with respect to the side frame 14, the movement of the friction member 18 subsequent to the deflection resulting from the initial deforma~ion of portions 18 and 20 before friction i5 broken between wear plate 36 and mating plate 32, is somewhat more abrupt than the transition of the arrangement of U. S. Patent No. /~,230,047. Nevertheless, such transition is still within comfortable operating ranges.
` To achieve the advantages of this invention3 while still maintaining the basic advantages of elastomeric bolster friction assemblies, it is necessary that the thickness of the mating plate 32 be no more than fifteen percent of the maximum transverse dimension of the friction member 18, as such transverse dimension is measured horizontally from the surEace 34 to the innermost end of the friction member 18. Preferably, the thlckness of mating plate 32 will be no more -than 3/16 of an inch.
Figs. 3 and 4 illustrate another embodiment of an elastomeric bolster friction assembly 52 which is constructed in accordance with the principles of the present invention.
Many of the structural and operational characteristics of bolster friction assembly 52 are similar to those of friction assembly 10 discussed hereinbefore. Accordingly, like elements will be identified with like numerals and similar elements will be identified with li~e numerals primed.
Furthermore, it is to be noted that the elastomeric bolster friction assembly 52 is, except for the incLusion of mating plates 32', substantially identical to the elastomeric bolster frietion assembly illustrated in Applicant's United States Patent No. 4,295,429. In this regard, a detailed description of the generally identical structural portions and the operations thereof is not necessary for a full understanding of this invention. Further, the illustration and brief deseription of the friction assembly 52 is included primarily to generally illustrate the scope and varied applications possible with Applicant's invention insofar as it is an improvement over a br~ad range o~
elastomeric bolster friction assemblies.
Friction assembly 52 comprises a pair of identical laterally spaeed adjacent elastomerie friction members 18' whieh are cooperable with suitable follower members 20' and spring assemblies 22' in a known manner. A wear plate 36' is seeured to thé column guide 52. The inner ~enerally vertically extending surface 56 of wear plate 36' eonsists of a pair of transversely adjacent sloped surface portions 54 whieh slope transversely outwardly from the transverse mid-point of the wear plate 36'. The vertically exten~ing outer-~ ~ sd~ -15-, ~ .
most surface 56 of each portion 28' also slopes transversely outwardly at an angle parallel to the slope of the adjacent portion 54. A mating plate 36 7 is suitably secured to each surface 56 such that in assembled position, a riction interface is established between adjacent surfaces 56 and 38'.
The requirements for the thickness of mating plates 36' are the same as the requirements for mating plates 36 as described hereinabove.
Thus, with a configuration of friction assemblies 52 as illustrated in Figs. 3 and 4, all of the requisite advantages of the elastomeric bolster friction assembly illustrated and described in U.S. Patent No. 4,295,429 are maintained while simultaneously acquiring the advantages of this invention, as were discussed hereinbefore with ref~rence to assembly 10 insofar as the metallic friction interface.
It is noted that the space 58 transversely intermediate adjacent friction members 18' is sufficient such that the adjacent mating plates 32' will not come into contact wlth each other during any transverse movement of the friction members 18'.
The invention herein is primarily directed to a side frame to bolster friction assembly having elastomeric friction means with a metallic face at the column guide interface. ~ -Accordingly, various changes can be made by those skilled in the art without departing from the scope of the invention herein, which is defined by the scope of the claims herein-after. For example: other configurations of elastomeric bolster friction assemblies which incorporate a mating plate 32 are contemplated; and the like.
~d/~
4,295,429 of October 20, 1981 has provided still a fur~her invention in the area of elastomeric ~riction members which possesses additional advantages of more controlled lateral restraint in substantially all conditions of operations of three~piece railway vehicles. Such advantages are obtained in this latter patent through the use of a pair of laterally adjacent elastomé~ic friction wedge portions which each engage a respective sloping wear plate surface. With such an arrangement, during lateral movement of a side frame with ~L~7~3 ~3 respect to the bols-ter, the lateral force on one of the wedge portions increases while the force on the other wedge portion is reduced. Furthermore, once friction is bro]~en be-tween the resisting wedge portions and the wear plate, the sloping surface of the wear plate permits the lateral sliding of the wedge portion while simul-taneousl~ providing a transverse wedging action to create a controlled resisting force to oppose the external lateral forces. This controlled lateral resisting force increases in proportion to the compressio~
modulus of the material and the sloping of the wear plate.
~urthermore, by providing even more controlled lateral restrai.nt, the invention therein still further increases the range of choices for the composition of side bearing elastomeric beari.ng blocks and additionally increases the circumstances under which elastomeric bear:iing blocks at the side bearing may no longer be required.
The elastomeric friction members described in the above-mentioned U.S~ Patents Nos~ 4,230,047 and 4,295,429 have proved to be significant advances over the art; however, 2~ in certain instances, limitations have been noted. More specifically, the mating surface of the elastomeric friction member is subject to galling, excessive fretting, wear and the like in the event of surface aberrations at the side frame column guide or wear plate interface or because of contaminants intermediate the sd/ -7_ mating surface of the friction member and wear plate. Furthermore~
e~perience has illustrated that to better insure more consistent control by friction member arrangements, the friction member should best be arranged to provide a somewhat uniform pressure at the side frame column guide. However, not all elastomers which rnight be utilized as an elastomeric friction member, have an appropriate composition within all operating parameters to provide such a uniform pressure. Still further, the very nature of the elastomer results in compression at the leading edge of the friction member towards the trailing edge (i.e., shortening the length of the mating face). Such non-uniform compression, which is at a maximum at the leading edge, results in excessive local pressure against the colurnn wear plate and excessive elastomer wear.
The present invention, which includes a thin metal face bonded or otherwise suitably secured to the mating face of the elas~omeric friction member, s~tbstantially maintains all of the advantages described hereinabove with respect to the prior elasto-meric friction members; however, the invention provides the ad-ditional advantages of curing, or in the least, substantially alleviating the above-mentioned limitations. Inasrnuch as the metal face is relatively thin in comparison to the body of the elasto-meric friction member, the friction member of the present invention (because it deforms in response to loading thereto prior to slip-ping~ generally incorporates the advantages of the prior friction wedges; however, it is to be ~mderstood that the slipping at the interface may be somewhat more abrupt than such prior wedges.
Nevertheless, because of the deformation prior to slipping as well as the other advantages resulting Erom the use of an elastomeric friction member (i.e., lateral constraint, hunting control, fit-up and the like), the present invention is significantly superior over the prior art rigid friction wedges.
Accordingly, it is one object of this invention to provide a bolster to side frame elastomeric friction assembly whioh provides smooth transition and dampingcharacteristics as well as having a superior matlng arrangement at the side frame to friction assembly interface.
It is another object of this invention to provide such an elastomeric friction assembly with improved means for insuring a more uniform pressure at the side frame column guide as well as to increase the useful life of the friction assembly.
~hese and other objects and advantages of the present invention will become more readily apparent upon a reading of the following description and drawings in which:
Fig. 1 is an enlarged partial side elevational view of one embodiment of an elastomeric bolster friction wedge assembly of the present invention in operational position on a conventional railway truck assembly;
Fig. 2 is a cross-sectional view of the embodiment illustrated in Fig. 1 as taken on lines 2-2 of Fig. l;
Fig. 3 is a partial side elevational view of another embodiment of an elastomeric bols-ter friction wedge assembly of the present invention in opera~ional position on a conventional railway truck assembly; and Fig. ~ i5 a cross-sectional wiew of the embodiment illustrated in Fig. 3 as taken on lines l~-~ of Fig. 3~
Referring to Figs. 1 and 2 there is illustrated an elastomeric friction assembly 10 of the present invention which is of the type utilized with a standard four-wheel freight car truck of a conventional design (only a portion of the bolster 12 of one of the side frames 1~ being shown) ~or supporting a car body (not shown).
The elastomeric ~riction assembly 10 is disposed within a pocket 16 formed in an axial end portion of the bolster 12. The assembly 10 is of a configuration which is adapted to be inser-ted within the bolster pocket 16 to replace prior art friction wedges (i.e., see U. S. Patent No. 3,461,815)`without the need to alter .
the standard configuration o~ exis-ting bolsters 12 and side fra~,e 14 of conventional freight car trucks.
At this point it is to be noted that the invention herein is primarily directed to an impro~ement over the rigid bolster to side frame riction wedges utilized heretofore and the operation and cooperation of such an improved arrangement with generally well known railway freight car components. Accordingly, other than as is necessary to describe the preferred embodiment of the invention herein with respect to the bolster and side frame relationship, the balance of the elements specified hereinabove need not be described in detail for a full and complete understanding of this invention to those skilled in the art. Furthermore, for purposes of description hereinafter, inner or inwardly and outer or outwardly shall refer respectively to towards and away from the centerplate (not shown) along the longitudinal axis of bolster 12 and upper and lower or upwardly and downwardly shall refer respectively to towards and away from the top of bolster 12 as viewed in the Figs.
Elastomeric friction assembly ]0 comprises: a friction member 18 and a spring follower member 20 which is biased inl~o engagement with member 18 by means of a spring assembly 22 which extends vertically upwardly between an upwardly facing lower seating surface (not shown) o~ the side fra-me 14 and a downwardly facing lower surface 24 of follower member 20. Follower member 20?,~which is formed of a suitable rigid material, such as steel or the like, haæ a generally upwardly extending triangular configuration and includes a downwardly open keeper pocket 26 formed within surface 24 for the captive retention of the upper end portion of spring assembly 22.
Friction members 18 comprise: an outer first portion of elastomeric material, illustrated as a generally rectangular porti,on 28; and an inwardly projecting integrally formed second portion of elastomeric material, shown as formed triangular portion 30i and a metallic sicle frame mating plate 32 which is secured to the outermost generally vertically extending face of portion 28 and which has a generally planer outer surface 3'4 thereof. Mating plate 32 extends along substantially the entire outer face of portion 28 and is secured thereto in any suitable manner, for example by bonding in th,e molding stage or by bolting.
A wear plate 36 having a generally vertically extending planer inner surface 38 is secured to the column guide 40 of each respective adjacent side frarne 14.
~ 3 With a general conEiguration as described above, when friction assembly 10 is biased into operational position thereof by spring assembly 22, the outer vertically extending surface 34 of mating plate 32 will be biased into engagement with the adjacent vertica]ly extending surface 38 of the column guide wear plate 3 and the lower surface 42 of triangular portion 30 will be in engagement with a complementary sloping sur~ace 44 oE follower 20.
Furthermore, the upper sloping surface 46 of triangular portion 30 will be aligned in a common sloping plane wi-th inner sloping sur-face 48 of follower 20 and the aligned surfaces ll~ and 48 will be in continuous engagement with the adjacent inclined surface S0 o~
the bolster pocket 26. Thus, the friction member 18 will be generally confined within the adjacent portions of the boundary surfaces 38, 50 and 44i however, the areas of portion 28 adjacent the upper and lower ends thereof will not be confined thereby allowing spaces for the elastomerîc portions of member 18 to de-form in shear.
At this point it is to be noted, except with respect to inclusion of mating plate 32 and the resultant advantages ofEered thereby, that the elastomeric bolster friction assembly 10 illustrated in Figs. 1 and 2 is virtually identical to the friction assembly illustrated in Fig. 4 of U. S. Patent No. 4,230 ! 047.
Accordingly, for purposes of the description of this invention, it will suffice to generally state that bolster Eriction assembly 10 possesses the advantages of such a prior elastomeric bolster friction assembly, such as:
~8~23 A. Fit-up of the side frame to bolster relationship because of the confined fit offered by the elastomeric portions of member 18;
B. ~bility to vary the pre-load friction forces by varying the spring constant of the spring assembl~ 22 or by varying the "self actuation angle";
C. Providing a smoother transition of the friction member 18 from sta-tlonary to sliding rather than the abrupt "stick-slip" action of prior art rigid friction wedges;
D. Avoiding excessive wear, abrading or gulling of the mating metallic surfaces; and E. Contributing to a controlled bolster to side frame restraint to thus inhibit hunting.
In the event that more detail is desired with respect to the primary operation of the known elastomeric bolster friction assemblies and/or of the advantages specified hereinabove, reference is hereby made to U. S. Patent No. 4,230,047.
Thus, the bolster friction assembly 10 of the present invention achieves the advantages o~ the prior elastomeric fricti.on assemblies but cures, or substantially alleviates, certain limita-tions of such prior assemblies. Specifically, the inclusion of the metallic mating plate 32 results in more consistent operation and a longer life of the friction member 18 by providing a metal to metal interface at the mating faces 34 and 38. Furthermore, the pressure at the faces 34 and 38 will be more consistent and, inasmuch as the leading edge of the elastomer (i.e., either the top or bottom of the ou-termost portion of rectangular portion 28 -].3--depending upon the direction of the force transmitted to assembly 10~ is bonded or otherwise suitably secured to the mating plate 32, any tendency of the elastomeric material at the leading edge of the rectangular portion 28 to curl under is alleviated.
It is to be noted that the -thickness of the mating plate 32 is dimensioned such that the elastomer of portions 18 and 20 is of a suEEicient mass to provide the requisite operational characteristics of an elastomeric bolster friction assembly of the type illustrated in U. S. Patent No. 4,230,047. On balance, the only adverse operational distinction between the ideal described`
in such Patent and the present invention is that during vertical movement of the bolster 12 with respect to the side frame 14, the movement of the friction member 18 subsequent to the deflection resulting from the initial deforma~ion of portions 18 and 20 before friction i5 broken between wear plate 36 and mating plate 32, is somewhat more abrupt than the transition of the arrangement of U. S. Patent No. /~,230,047. Nevertheless, such transition is still within comfortable operating ranges.
` To achieve the advantages of this invention3 while still maintaining the basic advantages of elastomeric bolster friction assemblies, it is necessary that the thickness of the mating plate 32 be no more than fifteen percent of the maximum transverse dimension of the friction member 18, as such transverse dimension is measured horizontally from the surEace 34 to the innermost end of the friction member 18. Preferably, the thlckness of mating plate 32 will be no more -than 3/16 of an inch.
Figs. 3 and 4 illustrate another embodiment of an elastomeric bolster friction assembly 52 which is constructed in accordance with the principles of the present invention.
Many of the structural and operational characteristics of bolster friction assembly 52 are similar to those of friction assembly 10 discussed hereinbefore. Accordingly, like elements will be identified with like numerals and similar elements will be identified with li~e numerals primed.
Furthermore, it is to be noted that the elastomeric bolster friction assembly 52 is, except for the incLusion of mating plates 32', substantially identical to the elastomeric bolster frietion assembly illustrated in Applicant's United States Patent No. 4,295,429. In this regard, a detailed description of the generally identical structural portions and the operations thereof is not necessary for a full understanding of this invention. Further, the illustration and brief deseription of the friction assembly 52 is included primarily to generally illustrate the scope and varied applications possible with Applicant's invention insofar as it is an improvement over a br~ad range o~
elastomeric bolster friction assemblies.
Friction assembly 52 comprises a pair of identical laterally spaeed adjacent elastomerie friction members 18' whieh are cooperable with suitable follower members 20' and spring assemblies 22' in a known manner. A wear plate 36' is seeured to thé column guide 52. The inner ~enerally vertically extending surface 56 of wear plate 36' eonsists of a pair of transversely adjacent sloped surface portions 54 whieh slope transversely outwardly from the transverse mid-point of the wear plate 36'. The vertically exten~ing outer-~ ~ sd~ -15-, ~ .
most surface 56 of each portion 28' also slopes transversely outwardly at an angle parallel to the slope of the adjacent portion 54. A mating plate 36 7 is suitably secured to each surface 56 such that in assembled position, a riction interface is established between adjacent surfaces 56 and 38'.
The requirements for the thickness of mating plates 36' are the same as the requirements for mating plates 36 as described hereinabove.
Thus, with a configuration of friction assemblies 52 as illustrated in Figs. 3 and 4, all of the requisite advantages of the elastomeric bolster friction assembly illustrated and described in U.S. Patent No. 4,295,429 are maintained while simultaneously acquiring the advantages of this invention, as were discussed hereinbefore with ref~rence to assembly 10 insofar as the metallic friction interface.
It is noted that the space 58 transversely intermediate adjacent friction members 18' is sufficient such that the adjacent mating plates 32' will not come into contact wlth each other during any transverse movement of the friction members 18'.
The invention herein is primarily directed to a side frame to bolster friction assembly having elastomeric friction means with a metallic face at the column guide interface. ~ -Accordingly, various changes can be made by those skilled in the art without departing from the scope of the invention herein, which is defined by the scope of the claims herein-after. For example: other configurations of elastomeric bolster friction assemblies which incorporate a mating plate 32 are contemplated; and the like.
~d/~
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A friction assembly for a railway truck of the type adapted to be received within an open ended pocket of a bolster with an outer surface thereof engaging a wear surface of a column guide portion of a side frame, said friction assembly comprising:
a resilient elastomeric member adapted to be received within at least the inner portion of such an open ended pocket with an ex-terior surface portion thereof in engagement with a rigid surface of such a pocket;
a rigid metal member engagable with said elastomeric member through-out a contact zone in a manner to sustain no more than limited rela-tive movement therebetween within said contact zone;
said rigid metal member having an outer surface portion adapted to engage such a wear surface;
means cooperable with at least one of said members for biasing said elastomeric member with said exterior surface portion thereof being in frictional engagement with such rigid surface of such a pocket and for biasing said rigid metal member with said outer surface por-tion thereof being in frictional engagement With such a wear sur-face;
and said means being operable to permit said resilient elastomeric member to deform during relative movements between such bolster and such wear surface during which relative movements said elastomeric member is deformed in compression until the effect of the biasing of said rigid metal member is overcome and said rigid metal member moves with respect to such a wear surface.
a resilient elastomeric member adapted to be received within at least the inner portion of such an open ended pocket with an ex-terior surface portion thereof in engagement with a rigid surface of such a pocket;
a rigid metal member engagable with said elastomeric member through-out a contact zone in a manner to sustain no more than limited rela-tive movement therebetween within said contact zone;
said rigid metal member having an outer surface portion adapted to engage such a wear surface;
means cooperable with at least one of said members for biasing said elastomeric member with said exterior surface portion thereof being in frictional engagement with such rigid surface of such a pocket and for biasing said rigid metal member with said outer surface por-tion thereof being in frictional engagement With such a wear sur-face;
and said means being operable to permit said resilient elastomeric member to deform during relative movements between such bolster and such wear surface during which relative movements said elastomeric member is deformed in compression until the effect of the biasing of said rigid metal member is overcome and said rigid metal member moves with respect to such a wear surface.
2. In a friction assembly of a type for use in a standard three-piece railway truck having a bolster supported by spaced side frames and adapted to be retained by retention means within an open ended pocket of such a bolster adjacent a column guide wear surface of such a side frame, said friction assembly comprising:
resilient elastomeric means adapted to be received within at least an inner portion of such a pocket;
rigid means adapted to be received intermediate said resilient elas-tomeric means and such an adjacent wear surface;
said resilient elastomeric means including a surface portion adapted to be maintained in frictional engagement with an adjacent surface of such a pocket located at least in part inwardly of such a pocket;
said rigid means including an outer surface portion adapted to be maintained in frictional engagement with such an adjacent wear sur-face;
said resilient elastomeric means being engageable with said rigid means along respective complementary surface portions thereof in a manner to permit no more than limited relative movement therebetween;
bias means operable to simultaneously maintain each of such fric-tional engagements;
and said resilient elastomeric means being deformable during rela-tive movement of such a bolster with respect to such a side frame in a manner to maintain the frictional engagement of said outer surface portion with such an adjacent wear surface without slipping until said deformation reaches a given magnitude.
resilient elastomeric means adapted to be received within at least an inner portion of such a pocket;
rigid means adapted to be received intermediate said resilient elas-tomeric means and such an adjacent wear surface;
said resilient elastomeric means including a surface portion adapted to be maintained in frictional engagement with an adjacent surface of such a pocket located at least in part inwardly of such a pocket;
said rigid means including an outer surface portion adapted to be maintained in frictional engagement with such an adjacent wear sur-face;
said resilient elastomeric means being engageable with said rigid means along respective complementary surface portions thereof in a manner to permit no more than limited relative movement therebetween;
bias means operable to simultaneously maintain each of such fric-tional engagements;
and said resilient elastomeric means being deformable during rela-tive movement of such a bolster with respect to such a side frame in a manner to maintain the frictional engagement of said outer surface portion with such an adjacent wear surface without slipping until said deformation reaches a given magnitude.
3. The friction assembly as claimed in Claim 2 wherein said resilient elastomeric means is additionally deformable beyond said given magnitude of deformation during additional relative move-ment of such a bolster with respect to such a side frame to maintain the frictional engagement of said outer surface portion with such an adjacent wear surface without slipping while partially maintaining the frictional engagement of said surface portion of said resilient elastomeric means with such an adjacent surface of such a pocket until such additional deformation reaches a greater given magnitude greater than the first mentioned said given magnitude.
4. The friction assembly as claimed in Claim 3 wherein said outer surface portion is movable with respect to such an adjacent wear surface in frictional engagement therewith during relative move-ment of such bolster with respect to such a side frame which exceeds said greater given magnitude.
5. In a friction assembly of a type for use in a standard three-piece railway truck having a bolster supported by spaced side frames and adapted to be retained by retention means within an open ended pocket of such a bolster adjacent a column guide wear surface of such a side frame, said friction assembly comprising:
a resilient elastomeric member adapted to be received within at least an inner portion of such a pocket;
said resilient elastomeric member including a support surface por-tion adapted to frictionally engage an inner support surface of such a pocket;
a rigid member adapted to be received within such a pocket inter-mediate such a wear surface and said resilient elastomeric member;
said rigid member including an outer surface portion adapted to frictionally engage such a wear surface;
said rigid member and said resilient elastomeric member including respective engagement portions for forming said friction assembly by mutual engagement thereof in a manner permitting no more than only limited relative movement between said rigid member and said resilient elastomeric member;
and said support and outer surface portions of said friction assem-bly being adapted to be maintained in said frictional engagement with such an inner support surface and such a column guide wear surface, respectively, when said friction assembly is retained by such retention means within such pocket of such standard three-piece truck.
a resilient elastomeric member adapted to be received within at least an inner portion of such a pocket;
said resilient elastomeric member including a support surface por-tion adapted to frictionally engage an inner support surface of such a pocket;
a rigid member adapted to be received within such a pocket inter-mediate such a wear surface and said resilient elastomeric member;
said rigid member including an outer surface portion adapted to frictionally engage such a wear surface;
said rigid member and said resilient elastomeric member including respective engagement portions for forming said friction assembly by mutual engagement thereof in a manner permitting no more than only limited relative movement between said rigid member and said resilient elastomeric member;
and said support and outer surface portions of said friction assem-bly being adapted to be maintained in said frictional engagement with such an inner support surface and such a column guide wear surface, respectively, when said friction assembly is retained by such retention means within such pocket of such standard three-piece truck.
6. The friction assembly as claimed in Claim 5 wherein said rigid member is a generally wedge shaped member.
7. The friction assembly as claimed in Claim 6 wherein said outer surface portion and said engagement portion of said rigid member extend on planes forming an acute angle.
8. The friction assembly as claimed in Claim 7 wherein said support surface portion and said engagement portion of said resilient elastomeric member extend substantially on parallel planes.
9. The friction assembly as claimed in Claim 8 wherein said engagement portion of said rigid member includes a retaining pocket which receives a portion of said resilient elastomeric member therein.
10. The friction assembly as claimed in Claim 9 wherein said engagement portion of said rigid member additionally includes abutment means for confining aid resilient elastomeric member within said retaining pocket.
11. The friction assembly as claimed in Claim 8 wherein said engagement portions of said resilient elastomeric member and said rigid member include respective pluralities of cooperably interfitting abutments and intervening cavities.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US27875581A | 1981-06-29 | 1981-06-29 | |
| US278,755 | 1981-06-29 | ||
| CA002011778A CA2011778C (en) | 1981-06-29 | 1990-03-08 | Railway truck bolster friction assembly |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1178123A true CA1178123A (en) | 1984-11-20 |
Family
ID=25674002
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000398614A Expired CA1178123A (en) | 1981-06-29 | 1982-03-17 | Railway truck bolster friction assembly |
| CA002011778A Expired - Fee Related CA2011778C (en) | 1981-06-29 | 1990-03-08 | Railway truck bolster friction assembly |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002011778A Expired - Fee Related CA2011778C (en) | 1981-06-29 | 1990-03-08 | Railway truck bolster friction assembly |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA1178123A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4915031A (en) * | 1981-06-29 | 1990-04-10 | Hansen, Inc. | Railway truck damping assembly |
-
1982
- 1982-03-17 CA CA000398614A patent/CA1178123A/en not_active Expired
-
1990
- 1990-03-08 CA CA002011778A patent/CA2011778C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4915031A (en) * | 1981-06-29 | 1990-04-10 | Hansen, Inc. | Railway truck damping assembly |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2011778C (en) | 1996-04-02 |
| CA2011778A1 (en) | 1991-09-08 |
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