Patent Publication Number: US-8978841-B2

Title: Universal brake assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-In-Part of U.S. patent application Ser. No. 11/480,804 filed Jul. 3, 2006, now issued as U.S. Pat. No. 7,931,130 on Apr. 26, 2011, and claiming priority from U.S. Provisional Patent Application Ser. No. 60/696,942 filed Jul. 6, 2005. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates, in general, to a brake mechanism for use in railway vehicle brake assemblies and, more particularly, this invention relates to a brake mechanism using a pneumatic brake actuator assembly for initiating a braking sequence in railway vehicle brake assemblies and, still more specifically, the invention relates to truck-mounted brake assemblies. 
     BACKGROUND OF THE INVENTION 
     As is generally well known in the railway industry, truck mounted braking systems comprise a series of force transmitting members, levers and linkages which function to move a group of brake shoes against the wheels of a railway vehicle to effect stoppage of such railway vehicle. A pneumatic brake actuator is typically provided in the braking system to initiate movement of this series of force transmitting members, levers and linkages to apply the brakes of the railway vehicle mounted to a truck assembly of the railway vehicle. 
     Traditional pneumatic brake actuators generally comprise an air cylinder piston which moves in a forwardly direction within a cylindrical member upon the application of pneumatic pressure thereto. A seal and/or diaphragm is provided on or adjacent a first end of the piston. This seal and/or diaphragm contacts the inner surface of the cylindrical member so as to provide an airtight chamber at one end of the cylindrical member such that application of pneumatic pressure therein and against the first end of the piston enables forward movement of the piston. 
     A piston rod is attached at a second end of the piston and moves in response to the movement of the piston. An opposite end of the piston rod is connected to the end of a push rod which is, in turn, connected to a cylinder force transfer lever. This cylinder force transfer lever is connected through a series of force transmitting members and linkages so as to activate a braking sequence and apply the brake shoes to the vehicle wheels. 
     As it is well known, their inability to accommodate piston bail or misalignment without leaking air, need for maintenance of the seals and/or diaphragms within the cylindrical member to ensure that leaking of air does not occur and difficulties in controlling the movement and/or force applied by the piston are the main disadvantages of the airbrake cylinder. 
     SUMMARY OF THE INVENTION 
     The invention provides a brake actuator assembly for a railway car mounted brake assembly. The brake actuator assembly includes a first end member having an inner surface. There is also a second end member which is disposed in spaced apart relationship with the first end member along the longitudinal axis of the brake actuator assembly and having an inner surface opposing the inner surface of the first end member. A hollow flexible elastomeric member extended between the inner surfaces of the first and the second end members along the longitudinal axis. The flexible elastomeric member has each of an exterior peripheral surface and a pair of open ends. A first peripheral flange is disposed on a first end of the hollow flexible elastomeric member and extending outwardly from the exterior surface thereof in a direction transverse to the longitudinal axis, the first peripheral flange has a first surface thereof abutting an inner surface of one of the first and second end members. There is also a second peripheral flange which is disposed on a second end of the hollow flexible elastomeric member and extending outwardly from the exterior surface thereof in the direction transverse to the longitudinal axis, the second peripheral flange has a first surface thereof abutting an inner surface of an opposed one of the first and second end members. A securing means is provided for securing in a substantially sealed manner each of the first and second peripheral flanges to a respectively positioned end member. An arrangement is disposed in the one of the first and second end members in open communication with a substantially sealed fluid chamber defined in the flexible elastomeric member and in fluid communication with a source of fluid under pressure. The securing means includes a pair of retaining member and pluralities of apertures and fasteners. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide a brake actuator assembly for a railway vehicle braking system that improves control of the brake shoe forces. 
     Another object of the present invention is to provide a brake actuator assembly that reduces the amount of pressure to be applied to the air spring actuator pushrod during light car conditions. 
     Still another object of the present invention is to provide a brake actuator assembly that is capable of linkage bail and/or misalignment without leaking air. 
     Yet another object of the present invention is to provide a brake actuator assembly that reduces effort required to maintain the air tightness of the system. 
     A further object of the present invention is to provide a brake actuator assembly that provides an economically desirable alternative to the seal/diaphragm system currently in use. 
     Still another object of the present invention is to provide a brake actuator assembly that provides for visual determination of its travel during brake actuation in order to determine the force applied by the brake shoes. 
     Yet an additional object of the present invention is to provide a brake actuator assembly which can be easily retrofitted into existing applications. 
     Although a number of objects and advantages of the present invention have been described in some detail above, various additional objects and advantages of the brake cylinder of the present invention will become more readily apparent to those persons who are skilled in the art from the following more detailed description of the invention, particularly, when such detailed description is taken in conjunction with both the attached drawing figures and with the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a railway vehicle truck mounted brake arrangement including a universal brake assembly of the instant invention; 
         FIG. 2  is a perspective view of the brake actuator assembly of the instant invention; 
         FIG. 3  is a front elevation view of the brake actuator assembly of  FIG. 2 ; 
         FIG. 4  is a side elevation view of the brake actuator assembly of  FIG. 2 ; 
         FIG. 5  is a rear elevation view of the brake actuator assembly of  FIG. 2 ; and 
         FIGS. 6   a - d  illustrate partial cross-sectional views of the brake actuator assembly along lines VI-VI of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF A PRESENTLY PREFERRED AND VARIOUS ALTERNATIVE EMBODIMENTS OF THE INVENTION 
     Prior to proceeding with the more detailed description of the invention, a description of a truck mounted braking system and its functioning should be helpful in understanding the present invention. Also, it should be noted that for the sake of clarity, identical components which have identical functions have been identified with identical reference numerals throughout the several views illustrated in the attached drawing figures. 
     Referring now to  FIG. 1 , there is shown a presently preferred embodiment of a truck-mounted brake assembly, generally designated  10 , for a railway car (not shown). This brake assembly  10  comprises brake beams, generally designated  2  and  3 , which are substantially identical. Each of the brake beams  2  and  3  includes a compression member  4 , a tension member  6  and a strut member  8 . The opposite ends of the compression member  4  and the tension member  6  may be permanently connected together, preferably by welding, along an outer segment (not shown) at the opposite ends of the compression member  4  and the tension member  6 . 
     At a location substantially midway between their opposite ends, the compression member  4  and the tension member  6  of the, respective, brake beams  2  and  3  are spaced apart sufficiently to allow connection of the strut member  8  therebetween. Mounted on the respective outer end segments of the brake beams  2  and  3  are brake heads  12 . 
     A pair of force-transfer levers  14  and  16  are pivotally connected by pins  18  to the strut member  8  of the respective brake beams  2  and  3 . One end of the respective force-transfer levers  14  and  16  is interconnected via a force-transmitting member  28 , which may be in the form of a slack adjuster device. The opposed end  36  of the force-transfer lever  16  is connected to a brake actuator assembly, generally designated as  200 , by connecting means  31  via a force-transmitting member or a return push rod assembly  32 . 
     Now in a particular reference to  FIGS. 2-5 , the brake actuator assembly  200  includes three essential members, such as a first end member, generally designated as  210 , a second end member, generally designated as  230  and a flexible elastomeric member, generally designated as  240 . 
     The first end member  210  connects the brake actuator assembly  200  to the force-transfer levers  14  and also seals one end of the flexible elastomeric member  240 . The first end member  210  is preferably rigid and includes a first portion  212  which is essentially a plate that is disposed generally vertical during operation of the brake actuator assembly  200 . Such first portion  212  has an inner surface  214  and an opposed outer surface  216 , which are substantially planar and are spaced apart from each other to define thickness of the first portion  212 . The first end member  210  may also include at least a second portion  220 , being also a plate shaped, that is disposed at the bottom edge  218  of the first portion  212  and extend outwardly from the inner surface  214 . The second portion  220  may extend in a direction substantially perpendicular to the first portion  214  or may be disposed at an angle thereto, as best shown in  FIGS. 3 and 5 . Preferably, the first portion  212  and the second portion  220  are formed integral with each other as a one-piece member, for example such as by a simple bending process. A pair of elongated spaced apart plate shaped members  72  are disposed on the second surface  216  and extend outwardly therefrom. Each of the pair of elongated spaced apart plate shaped members  72  has a conventional aperture  74  so as to connect the first end member  210  to the force-transfer levers  14 . The pair of elongated spaced apart plate shaped members  72  may be formed integral with the first portion  212  or may be attached thereto by way of fasteners and apertures. 
     The second end member  230  is also preferably rigid and has a portion  232  which is essentially a plate that is disposed generally vertical during operation of the brake actuator assembly  200 . Such portion  232  has an inner surface  234  and an opposed outer surface  236 , which are substantially planar and are spaced apart from each other to define thickness of the portion  232 . Furthermore, the inner surface  234  opposes the inner surface  214  of the first portion  212  of the first end member  210 . Means is disposed on and attached to the outer surface  236  so as to connect the brake actuator assembly  200  to the brake beam  4 . 
     Now in a particular reference to  FIGS. 6   a - d , the hollow flexible elastomeric member  240  extends between the first end member  210  and the second end member  230 . The flexible elastomeric member  240  has a predetermined shape and a predetermined length. The presently preferred shape of the flexible elastomeric member  240  has a generally annular cross-section in a direction transverse to a longitudinal axis  202  of the brake actuator assembly  200 . The flexible elastomeric member  240  further has a first open end  242  and an axially opposed second end  246 . The preferred material of such flexible elastomeric member  240  is a multi-ply rubberized fabric material. The shape of the flexible elastomeric member  240  may be a bellow, a simple cylindrical sleeve or any other shape suitable for reciprocal expansion and contraction along the longitudinal axis  202 . In either shape, the flexible elastomeric member  240  has a hollow interior. 
     A first peripheral flange  260  is provided and is disposed on a first end  242  of the hollow flexible elastomeric member  240 . The first peripheral flange  260  further extends outwardly in a direction transverse to the longitudinal axis  202  from the exterior surface  250  of the hollow flexible elastomeric member  240 . The first peripheral flange  260  has a generally planar first surface  262  thereof abutting an inner surface  214 ,  232  of one of the first and second end members,  210  and  230  respectively and being best shown as a first end member  210  in  FIGS. 6   a  and  6   c.    
     There is also a second peripheral flange  270  that is disposed on a second end  246  of the hollow flexible elastomeric member  240  and that also extends outwardly in the direction transverse to the longitudinal axis  202  from the exterior surface  241  of the flexible elastomeric member  240 . The second peripheral flange  270  has a generally planar first surface  272  thereof abutting an inner surface  214 ,  232  of an opposed one of the first and second end members,  210  and  230  respectively, and being best shown as a second end member  230  in  FIGS. 6   b  and  6   d.    
     Preferably, the first and second peripheral flanges,  260  and  270  respectively, are identical and have an annular shape. It is further preferred for the flanges  260  and  270  to be formed integral with the flexible elastomeric member  240  as a one-piece member, for example by a molding process. However, the thickness of each flange  260 ,  270  may differ from the thickness of the flexible elastomeric member  240 , so as to facilitate attachment of the flexible elastomeric member  240  to end members  210 ,  203 . 
     There is also means, generally designated as  280 , for securing, in a substantially sealed manner, each of the first and second peripheral flanges,  260  and  270  respectively, to a respectively positioned end member  210  or  230 . 
     The final element of the brake actuator assembly  200  is an arrangement  278  disposed in the one of the first and second end members  210 ,  230  in open communication with a substantially sealed fluid chamber  252  defined in the flexible elastomeric member  240  and in fluid communication with a conventional source of fluid under pressure (not shown). The arrangement  278  allows supply of fluid under pressure to inflate the sealed fluid chamber  252  causing a generally linear movement of one end member along the longitudinal axis  202  in a direction away from an opposed one end member and removal of the fluid under pressure will deflate the sealed fluid chamber  252  causing the generally linear movement of the one end member in a direction toward the opposed one end member, and whereby selective inflation and deflation of the flexible elastomeric member  240  causes a reciprocal motion of the brake actuator assembly  200  to move the control linkages  14 ,  16  and the force transmitting members  28 ,  31  for actuating and releasing the brake shoes. Here, the first end member  210  will reciprocally move relative to the second end member  230  which is stationary attached to the brake beam  4 . 
     The securing means  280  preferably includes a pair of retaining members  282 , which are preferably (annular) ring shaped, each engaging a predetermined portion of one of the first and second peripheral flanges,  260  and  270  respectively, and plurality of fastening means. As it will be explained below, the fastening means includes threaded fasteners and apertures formed through thickness of at least one of the first and second end member  210  and  230  respectively, the first and second peripheral flanges  260  and  270  respectively and the pair ring shaped members  282 . 
     In accordance with one form of the invention, one ring  282  has one substantially planar surface  284  thereof abutting the substantially planar second surface  264  of the first peripheral flange  260 , which defines such predetermined portion thereof, while the other ring  282  has the substantially planar surface  284  thereof abutting the substantially planar second surface  274  of the second peripheral flange  270 , which defines such predetermined portion thereof. Apertures  288 , which are preferably disposed in a circular pattern, are then formed through thickness of each of the end members  210 ,  230 , peripheral flanges  260 ,  270  and rings  282 . An elongated fastener  290 , such as a conventional bolt, is passed through each aperture  288 , and another threaded fastener  292 , such as a conventional nut, is operatively threaded onto the threaded end of the threaded fastener  290  and is advanced to essentially clamp each peripheral flange  260 ,  270  between its respective end member  210 ,  230  and the ring  282 . It would be understood that each aperture  288  is essentially consists of at least two, and generally three, different aperture portions that are aligned therebetween during assembly of the brake actuator assembly  200 . Alternatively to the nut  292 , the portion of the aperture  288  formed through either end member  210 ,  230  or ring  282  may be threaded. Yet alternatively, the elongated fastener  290 ′ may be a conventional stud that has one end thereof being pressed into an aperture in either end member  210 ,  230  or ring  282  and an opposed end thereof being threaded to operatively receive a threaded nut  292 , as best shown in  FIG. 6   c . It is also contemplated that threaded nut fastener  292  may be permanently secured to either end member  210  or  230  or the retaining member  282 , for example by a welding process. 
     In accordance with another form of the invention, at least one, and preferably each retaining member  282  is imbedded within a respective peripheral flange  260 ,  270 . The term imbedded is meant to define here that the retaining member  282  is surrounded by material of the respective peripheral flange  260 ,  270 , as best shown in  FIG. 6   d . For example the retaining member  282  may be placed into the mold during molding operation of the peripheral flange  260  or  270 . The apertures  288  are then formed through at least the partial thickness of the peripheral flange  260  or  270 , including retaining member  282 , and through the end member  210  or  230 . Thus, in this embodiment, the predetermined portion of each of the first and second flange  260  and  270  respectively is a body portion thereof. Here, the portion of the aperture  288  formed through imbedded retaining member  282  may be threaded so as to eliminate use of the threaded nut  292 . Optionally, a plurality of retaining members, rather than one continuous retaining member  282 , may be imbedded within the flange  260  and/or  270 . 
     If required, an optional sealant  278  can be applied to either end member  210 ,  230  or peripheral flanges  260 ,  270  prior to fastening such members therebetween. Furthermore, the surfaces  264  and  274  may be provided with serrations or ridges (not shown) to facilitate sealing of each flange  260 ,  270  to a respectively positioned end member  210 ,  230 . 
     Brake actuator assembly  200  may include optional means, generally designated as  300 , for indicating travel distance of the brake actuator assembly  200 . By way of an example only, such means  300  for indicating travel distance includes a portion  302  extending from an edge of one of the pair of end members  210 ,  230  substantially planar therewith and a plate shaped member  304  disposed on and extending outwardly from the inner surface of the opposed one of the pair of end members  210 ,  230 . The plate shaped member  304  is adapted with at least one notch  306  formed through a thickness thereof, whereby the portion  302  is disposed generally perpendicular to the plate member  304  so that thickness of the portion  302  moves within the at least one notch  306  during brake application and release. Preferably the bottom edge  308  of the at least one notch  306  has an irregular shape so as to clearly indicate various operating conditions of the brake actuator assembly  200 . 
     Currently used brake cylinder assemblies may be retrofitted with the brake actuator assembly  200  of the instant invention by replacing the cylinder assembly with the brake actuator assembly  200  having a predetermined push rod/shield and mounting bracket arrangements to interface with the existing brake rigging, either truck mounted or car mounted. 
     Thus, the present invention has been described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same. It will be understood that variations, modifications, equivalents and substitutions for components of the specifically described embodiments of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.