Patent Publication Number: US-3876081-A

Title: Railway draft rigging

Description:
United States Patent 1 1 Metzger 1 RAILWAY DRAFT RIGGING William J. Metzger, East Cleveland, Ohio [73] Assignee: Midland-Ross Corporation,  
 Cleveland, Ohio 221 Filed: Oct. 10, 1973 211 App]. No.: 405,075  
 [75] Inventor:  
 [S2] U.S. Cl. 213/69 [5 1] Int. Cl. B6lg 9/00 [58] Field of Search 2l3/50, 50.5, 62, 64, 67, 2l3/69 [56] References Cited UNITED STATES PATENTS 2,889,940 6/l959 Metzger 2l3/69 3,568,857 3/l97l Altherr 2l3/067 X 1 Apr. 8, 1975 Primary E.raminerM. Henson Wood, Jr. Assistant Examinerkm A. Church Attorney, Agent, or Firm-Henry Kozak [57] ABSTRACT A railway car coupler having its butt end pivotally connected by a vertically extending cylinderical pivot pin to the forward ends of the two vertically spaced arms of a horizontal yoke housing a conventional draft gear and flat faced front follower has a butt end surface of extended width with a flat central surface portion of at least 4-% inches width extending perpendicularly to the longitudinal axis of the coupler and tangentially joining at each side with corresponding convexly curved relieved contour side end extensions for rocking engagement with the front follower with minimal wear therebetween while also providing effective alignment control means for the coupler.  
 10 Claims, 11 Drawing Figures RAILWAY DRAFT RIGGING BACKGROUND OF THE INVENTION This invention relates in general to railway draft rigging and, more particularly. to a draft rigging embodying alignment control means for the associated railway vehicle.  
  The A.A.R. (American Association of Railroads) standard E coupler in general use at present on railroad cars in freight service in the US. is provided with a shank terminating in a butt end housed within the head portion of a yoke and connected thereto by a horizontal cross key passing through horizontally extending slots in the coupler shank and the yoke head. The butt end of the coupler shank is provided with a rearwardly facing flat butt end surface having a width of approximately 5-: inches and disposed perpendicularly to the longitudinal axis of the coupler. During buffing operations this flat butt end surface abuts against an opposing flat face on the front follower plate of an associated draft gear assembly housed within the yoke to transmit the buffing forces to the draft gear for absorption thereby.  
  It is a known fact that such standard cross key type coupler and yoke arrangements do not provide ideal bearing surfaces during all pulling and buffing operations in service, especially when couplers are in laterally displaced angled position. In such angled positions, the coupler shank has undesirable corner bearings against the cross key during pulling operations and against the front follower in buffing operations. The wear resulting from the concentrated load thus applied at such times at the corner in the rear end of the key slot in the coupler shank and at the coupler butt end requires costly reclamation procedures to maintain the bearing surface. This is particularly important due to the fact that the bearing surface between the rear end of the key slot in the coupler shank and the cross key is minimal, being only about 8.05 inches. For another thing, the car alignment control action provided by such standard horizontal cross key type coupler arrangements for E couplers is not anywhere near as effective as desired, it being considerably less effective in this regard, for example, then that afforded by the present standard F coupler arrangements where the coupler is diplaced more than about 2 inches from its normal centered position on the car. Consequently, derailments of freight cars equipped with such standard hori zontal cross key type coupler arrangements are more apt to occur in present day freight train service in view of the greatly increased tractive and starting forces which are provided by the diesel locomotives generally employed for such service and which permit longer and higher tonnage freight trains.  
  The above mentioned and other undesirable conditions characteristic of the standard horizontal cross key type coupler-yoke arrangements employed for standard E type couplers therefore dictate that an improved form of coupler and yoke arrangement be devised for such application which will obviate all these undesirable conditions. The need for such an improvement is further dictated by the fact that the almost universal adoption of diesel locomotives for freight train service with their increased tractive and starting forces that permits longer and higher tonnage trains has outmoded further continued use of the present standard horizontal cross key yoke arrangement both in principle and strength characteristics.  
 SUMMARY OF THE INVENTION It is an object of the invention therefore to provide a novel and improved railway coupler shank and yoke assembly which overcomes all the above mentioned disadvantages.  
  Another object of the invention is to provide an improved railway coupler shank and yoke assembly of simple and inexpensive construction and affording effective alignment control means for the associated railway vehicle.  
  Still another object of the invention is to provide a novel coupler shank and yoke assembly for railway vehicles having increased strength and increased load bearing areas with resultant reduced wear and maintenance costs.  
  A further object of the invention is to provide a railway coupler and yoke assembly which embodies the improved construction referred to above and which is directly applicable to all existing freight cars.  
  Briefly stated, in accordance with one aspect of the invention, a railway coupler having its butt end pivotally connected by a vertically extending cylindrical pivot pin to the head portion of a horizontal yoke for horizontal swing movement of the coupler relative thereto, has its butt end surface comprised of a flat central surface portion of substantial horizontal width disposed perpendicularly to the longitudinal axis of the coupler and tangentially joining at each side with corresponding convexly curved relieved contour side end extensions for rocking engagement with a flat faced front follower ofan associated draft gear assembly at contact points therebetween so located relative to the longitudinal center line of the coupler that buffing forces applied to the coupler in any horizontally displaced position thereof on the vehicle up to at least 3- /5; inches are directed toward the center of the vehicle along force lines which intersect the vehicle center line at points rearwardly of the pivot center of the adjacent wheel truck of the vehicle. A coupler shank and yoke assembly is thereby provided which not only incorporates highly effective alignment control means for the coupler mounting but which at the same time is characterized by a simple and inexpensive construction possessing increased bearing surface areas and resulting reduced wear thereof in service.  
  Further objects and advantages of the invention will appear from the following detailed description of species thereof and from the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWING In the drawing:  
  FIG. 1 is a plan view of a railway coupler and yoke arrangement comprising the invention, partly in section on the line l1 of FIG. 2;  
  FIG. 2 is a side elevation of the coupler and yoke arrangement shown in FIG. 1, partly in section on the line 22 of FIG. 1;  
  FIG. 3 is a vertical section taken on the line 33 of FIG. 2;  
  FIG. 4 is a plan view on an enlarged scale of the butt end portion of the coupler comprising the invention and the cooperating front follower of an associated draft gear assembly;  
  FIG. 5 is a plan view, partly in section, of an A.A.R. standard type E coupler and yoke arrangement shown partly in horizontal section through the key slot of the coupler and with the coupler in its maximum laterally displaced angled position on an associated railway car;  
  FIG. 6 is a plan view similar to FIG. 5 of a coupler and yoke arrangement comprising the invention showing the coupler in its maximum laterally displaced position on the railway car;  
  FIG. 7 is a plan view, partly in section, ofthe butt end portion of an A.A.R. standard Type E coupler showing the extent to which an associated front follower and draft gear are compressed when the coupler is horizontally displaced an angle of 5 from its normal centered position on an associated railway car;  
  FIG. 8 is a view similar to FIG. 7 but showing instead the butt end portion of a coupler comprising the invention horizontally displaced a corresponding 5 angle;  
  FIG. 9 is a plan view, partly in section, of another form of the invention embodied in an engine pilot coupler;  
  FIG. 10 is a plan view, partly in section, of the embodiment illustrated in FIG. 9 but with the coupler shown in a laterally displaced position of an associated locomotive; and  
  FIG. 21 is a plan view on an enlarged scale of the butt end portion of the engine pilot coupler shown in FIGS. 9 and 10.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 14, the invention is therein illustrated as embodied in an A.A.R. Standard E type railway coupler 10 of cast steel and comprising the conventional head portion 12 and projecting shank portion 14. The coupler I0 is mounted on an end ofa strandard railroad car body with its shank portion 14 projecting into the end of the customary center sill 16 of the car between the spaced longitudinal extending side walls 18 thereof and with its head portion 12 projecting outwardly therefrom. The coupler shank 14 projects through an opening 20 in a conventional steel striker casting 22 secured within the end of the center sill l6, and it rests on the usual steel carrier casting 24 supported on the striker casting 22 within the opening 20 thereof.  
  The coupler 10 is arranged to cooperate at its inner or butt end portion 26 with a conventional type draft gear assembly 28 which comprises the usual steel front follower 30 and a draft gear as indicated by the crossed dotdash lines 32 and which is compressed between the customary front and rear stop lugs 34 and 36, respec tively, secured to the car center sill l6 and forming therewith the draft gear pocket. The draft gear assembly 28 is housed between the upper and lower vertically spaced horizontally extending arms 38 and 40, respectively. of a vertical plane cast steel yoke 42 mounted within and extending longitudinally of the car center sill 16 between the two side walls 18 thereof and resting at its bottom side on a pair of spaced support plates 43 secured to the center still. The yoke 42 is positioned in the center sill 16 with its closed or bight end 44 innermost for engagement with the inner end of the draft gear assembly 28 during draft movements of the coupler l0 and yoke 42 to absorb the pulling force on the coupler, and with its open head end 46 facing outwardly toward the open end of the center sill and straddling the butt end portion 26 of the coupler shank 14. The butt end surface 48 of the coupler 10 engages with the flat front face 50 of the front follower 30, during buffing movement of the coupler, to effect the compression of the draft gear 32 and absorption of the buffing force applied to the coupler. The portions of the two yoke arms 38, 40 comprising the head end 46 of the yoke are tied together at their opposite sides, and only at their forwardmost ends, by a pair of relatively narrow side walls or tie struts 52 extending longitudinally of the yoke arms.  
 For increased strength purposes, the portions of the yoke arms 38, 40 extending rearwardly from the head end 46 of the yoke are made of increased crosssectional area compared to that of the standard Y40 yoke presently employed with A.A.R. standard Type E couplers. To this end, these yoke arm portions 38, 40, while having the same l-Va inch thickness as the corresponding arm portions of the standard Y40 yokes, are  
 made of the greater 5-% inch width employed for the yoke arms of the standard Y45 yoke presently used with A.A.R. standard Type F Interlocking couplers instead of the smaller 5 inch width employed for the yoke arms of the standard Y40 yoke. Likewise, for purposes of added strength, the yoke arms 38, 40 widen to a width of at least approximately 8-% inches at the region of the front follower 30 and throughout the length of the head end 46 of the yoke, compared to the approximate 7-&#34;/a inch width of the yoke arms of a standard Y40 yoke at the region immediately forward of the front follower.  
  In the standard horizontal cross-key type coupleryoke arrangement presently employed for A.A.R. Standard *E&#34; type couplers, the coupler and yoke are interconnected by a horizontal steel key 54 (FIG. 5) extending crosswise of the car center sill 16 through aligned horizontal slots 56 and 58, respectively, located in the shank 60 of the E type coupler 62 and in the side walls 64 of the head end portion 66 of the standard Y40 yoke 68, and through slots 70 in the side walls 18 of the center sill l6 and striker casting 22. As mentioned hereinabove, such horizontal cross-key type coupler-yoke arrangements do not provide ideal bearing surfaces during all pulling and buffing operations in service. Thus, when the coupler 62 is in a horizontally angled position as shown in FIG. 5, the coupler shank 60 has undesirable corner bearing against the cross key 54 during pulling operations as indicated at 72, and against the front follower 30 in buffing operations as indicated at 74. The concentrated load thus applied at these corner bearings consequently results in a relatively high rate of wear thereof and shank shortening such as requires costly reclamation procedures to maintain the bearing surfaces.  
  In the coupler and yoke arrangement according to the invention, the coupler 10 is pivotally connected at its butt end 26 to the head end 46 of the yoke 42 by a vertically extending cylindrical steel pivot pin 76, for horizontal swing movement or swiveling of the coupler relative to the yoke about a vertical pivot axis P intersecting the longitudinal center line A of the interconnected coupler and yoke. The pivot pin 76 is of large enough diameter to provide an adequate bearing surface with the coupler and the yoke. To this end, a pivot pin 76 having a diameter of about 3 1% inches, for example, is satisfactory for the purposes of the invention.  
  The pivot pin 76 is located in the butt end 26 of the coupler shank 14 with its axis P located a distance of about 4 inches back from the butt end surface 48 of the coupler shank l4, and it is received within aligned openings 78 and 80, respectively, located in the coupler butt end 26 and in the forward end portions of the yoke arms 38 and 40 forming the yoke head 46. As is customary in pivotally interconnected coupler and yoke arrangements, the pin-receiving openings 78 and 80 are made slightly oversize in diameter, e.g., by about A: inch, in order to freely receive the pivot pin 76 during the assembly of the coupler and yoke. The opening 78 is also slightly elongated in the direction of the coupler longitudinal axis A, e.g., by about 5/32 inch, so as to be of slightly oval shape to provide clearance for assuring application by the coupler of all buffing forces to the front follower 30 rather than to the pivot pin 76 such as might possibly result in the breakage thereof. The pivot pin 76 is retained in place in the coupler butt end and yoke arms against dropping out therefrom by a bar-shaped retainer key 82 which is mounted on and extends horizontally across the underside of the head end 46 of the yoke 42 and at least partially underlies the lower end of the pivot pin. The retainer key 82 is mounted in a support lug 84 depending from the underside of the head end portion of the lower arm 40 of the yoke 41, and it is locked place in the support lug 84 by a head portion 86 (FIG. 3) formed on the key at one end and by a cotter pin 88 inserted in the other end of the key that projects outwardly from the lug 84. The pivot pin 76 is prevented from creeping upwardly in the pin-receiving openings 78 and 80, under the influence of the impacts and vibrations to which it is subjected in service, and projecting above the upper side of the head end 46 of the yoke 42 so that it could strike against the back end of the striker casting 22 during pull movement of the coupler 10 and so prevent full travel of the draft gear 32, by a pin retainer plate or bar 90 which extends horizontally across the upper side of the head end 46 of the yoke 42 and at least partially over the pin-receiving opening 80 therein so as to over lie the pivot pin. The pin retainer plate 90 is welded at its opposite ends to the yoke head end, as indicated at 92 in FIG. 3.  
  Further in accordance with the invention, the butt end surface 48 of the coupler 10 is formed ofa particular contour which, in combination with the pivotal interconnection of the coupler and yoke as described above, operates to provide, in opposed abutting cooperation with a conventional type from follower 30 of simple flat-faced form as shown, not only greatly increased coupler bearing surfaces during buffing operation in all positions of the coupler on the railway vehicle or car with resulting decreased coupler wear and maintenance cost, but also as well highly efficient alignment control means for the vehicle. Referring to HQ 4 in particular, the butt end surface 48 according to the invention is comprised of a relatively wide flat central portion 94 extending perpendicularly to and centered about the longitudinal axis A of the coupler l0 and having a width of at least approximately 4-% inches, and tangentially joining at each side with correspondingly convexly curved relieved contour side end portions or extensions 96 of appreciable lateral extent for rocking engagement with the front follower 30 on horizontal swing movement or angling of the coupler about its vertical pivot axis P. The curved side end portions 96 are relieved at their outermost ends a distance of at least about 5/32 inch back from the vertical B-B of the flat central surface portion 94 and their outermost ends are spaced at least about 3 inches from the longitudinal center line A of the coupler to provide, along with the flat central surface 94, an overall butt end surface width of at least about 7- /2 inches. The curved side end portions 96 each have a lateral extent of at least about one-sixth or 16-95 percent of the overall width of the coupler butt end surface 48.  
  In the case of the particular coupler butt end 26 illustrated in FIGS. 1-4 for use on A.A.R. standard Type E couplers for freight car service, the flat central surface portion 94 of the coupler butt end surface 48 is of a width of about 5 inches and the tangentially adjoining curved side end portions or extensions 96 are curved on a radius of about 5 inches and terminate at points located about 3% inches from the longitudinal axis A of the coupler. The butt end surface 48 thus has an overall width of about 7- /2 inches and the curved side end portions 96 each have a lateral extent of about 1- /4 inches amounting to approximately one-sixth or 16% percent of the overall width of the coupler butt end surface 48. The 7-9: inch overall width of this butt end sur face 48, coupled with its height or vertical depth of approximately 6% inches, provides an appreciable total bearing surface area of around 48 square inches for transmission of the buffing forces to the front follower 30 as compared to the approximate 34- /2 square inches of the butt end surface of the present Type E coupler This represents very nearly a 40% increase in the total butt end bearing surface area for the coupler according to the invention. Also in the case of the particular coupler butt end construction 26 shown in FIGS. 1-4, it is provided with vertical side walls 98 extending forwardly of the coupler from the outer terminal points of the curved side end portions 96 of the butt end surface 48 in a direction approximately parallel to the longitudinal axis A of the coupler and terminating at corre sponding points located approximately on or only slightly beyond, e.g., around l inch or so forwardly of, the vertical plane C which passes through the pivot axis P of the coupler and extends perpendicularly to the longitudinal axis A thereof. From these forward points, the side walls 98 of the coupler butt end 26 taper in wardly and forwardly at a slight angle, for example. from 10 to 15 or so to the longitudinal axis A of the coupler, as shown in 100 in FIGS. 1 and 4, to meet with the slightly outwardly and forwardly tapering side wall portions 102 of the coupler shank 14 which join with the coupler head 12.  
  Referring to FIGS. 1 and 6, it will be seen that the head end portion 46 of the yoke 42 within which the butt end 26 of the coupler is received is entirely open at its opposite sides except for the narrow tie struts 52 which. as shown, are located entirely forwardly of the pivot axis P of the coupler 10. The open sides of the yoke head end 46 thus provide room for the accommo dation therein of the corners of the butt end 48 of the coupler, when it swivels about its pivot axis P in service, so as not to be interfered with by the yoke, Also for such purpose and as shown in FIGS. 1 and 6, the vertical inner side 104 of the yoke tie struts 52 which extend parallel to the longitudinal axis A of the yoke 42, are spaced apart a distance of around 7-% inches, which is slightly greater than the 7- /2 inch maximum width of the coupler butt end portion 26, and are flared out at their forwardmost ends as indicated at 106, to permit the coupler 10 to swing horizontally, without interference, to its limiting laterally displaced position of approximately 4-% inches, as determined by the engagement of the sides 102 of the coupler shank 14 with the sides of the striker casting 22 on the railway car or vehicle. Thus, the butt end portion 26 of the coupler l and its butt end surface 48 nearly fill the yoke head opening across its width between the inner side walls 104, the 7-/&amp; inch width dimension of the butt end portion 26 being almost 97 percent of the width of the yoke head opening.  
  Besides affording substantially increased bearing surfaces during both pull and buff operations in all positions of the coupler on the railway car or vehicle and eliminating undesirable corner bearings with resulting reduced wear and shank shortening and reduced maintenance cost, the coupler and yoke assembly comprising the invention, though of extremely simple and inex pensive construction, also provides at the same time a highly efficient alignment control means for the car with consequent improved safety against derailments. FIGS. and 6 provide a comparison of the effectiveness of the alignment control means afforded by the present standard horizontal crosskey type E60 coupler 62 and Y40 yoke 68 arrangement (FIG. 5) versus that provided by the coupler and yoke arrangement comprising the invention (FIG. 6). FIG. 5 illustrates the condition which exists in the present standard crosskey type coupler-yoke arrangement when the coupler is in its maximum laterally displaced position which, in present freight cars, amounts to 3- /3 inches at its coupling center point, without the coupler shank 14 contacting the side of the striker casting 22. In this maximum displaced position of the coupler 62, the yoke 68, as shown, is angled relative to the car center line L to a maximum position, as determined by the engagement of its forward head end 66 with the striker casting 22 within the car center sill l6 and the engagement of its rearward end with one of the rear stop lugs 36 on the center sill. Under the conditions shown in FIG. 5, the contact point 74 between the coupler butt end surface and the front face 50 of the front follower is so lateraliy spaced from the longitudinal center line L of the car that the force line f representing the direction of a buffing force F applied to the coupler 62 when in such angled position and passing through the aforementioned contact point is directed at an angle a of around 3 to, and intersects, the car center line L at a point X forwardly of the vertical pivot axis T of the car truck (not shown), and its exerts a lateral force component l on the truck tending to push it sideways off the track and derail it which is equal to F sin a, or approximately 0.0523F in the case of the particular 3 angled force line f This distance of the intersection point X forwardly of the truck center or pivot point T and resultant lateral force component I of the buffing force F tending to cause a derailment, increases as the coupler is laterally displaced further than shown in FIG. 5 to contact the side of the striker casting 22, such as might occur after wear of the coupler and yoke and other parts in service.  
  With the improved coupler and yoke arrangement according to the invention and as shown in FIG. 6, however, the contact point between the coupler butt end surface 48 and the front face of the follower 30 is so laterally spaced from the car center line L that the force line f of buffing forces F applied to the coupler 10 when angled to the same degree as the 3-% inch maximum lateral displacement of the present standard cross-key type coupler and yoke arrangement shown in FIG. 5 and passing through such contact point is directed at an appreciably shallower angle b of around l or so to, and intersects, the car center line L at a point (not shown) a considerable distance to the rear of the adjacent car truck center pivot axis T. Consequently, it exerts a lateral force component I&#39; on the adjacent car truck tending to push it sideways off the track equal to only 0.0175F, which is of considerably less magni tude, i.e., around 67 percent less than that exerted by t the standard cross-key coupler and yoke arrangement under equivalent conditions. In the coupler and yoke arrangement according to the invention, moreover, the coupler 10 has a maximum lateral displacement, at its coupling center point, as determined by the engagement of the coupler shank 14 with the side of the striker casting 22, amounting to about 4-% inches, which is approximately 1 inch or 28 percent greater than that of the coupler of a standard cross-key type coupler and yoke arrangement. Even in such substantially greater maximum displaced position, however, of a coupler comprising the invention, the contact point between the coupler butt end surface 48 and the front follower is so laterally spaced from the car center line L that the force linej&#34; of buffing forces F&#34; applied by the coupler to the adjacent car truck and passing through such contact point is directed at an angle c to the center line L of the car of around 2-% or so which is still less than the approximate 3 angle of the coupler ofa standard cross-key type coupler and yoke arrangement when in its maximum laterally displaced position, and it also intersects the car center line L at a point (not shown) located an appreciable distance to the rear of the center pivot point T of the adjacent car truck. The lateral force component 1&#39;&#39; of such a Z-Vz&#34; angled buffing force F&#34; which is applied to an adjacent car truck and tends to push it sideways off the track is therefore equal to approximately 0.0436F, or around l7 percent less than that applied by a standard crosskey type coupler and yoke arrangement in its maximum laterally displaced position ofonly 3-% inches. It will be evident from the above, therefore, that the coupler and yoke arrangement according to the invention provides greatly improved car alignment to prevent derailment as compared to that provided by the standard cross-key type E coupler and Y40 yoke arrangement in general use at present in freight car service.  
  Referring to FIG. 5, it will be noted that with the present standard cross-key type coupler-yoke arrangement, when the coupler 62 is angled or swiveled to its limiting 3-% inch horizontally displaced position, the yoke 68 must be horizontally angled to its limiting angular position within the side walls 18 of the car center sill 10 in order to allow the coupler 62 to swing to such maximum displaced position. With the coupler and yoke arrangement according to the invention, however, as shown in FIG. 6, the yoke 42 remains in its central position longitudinally aligned with the car longitudinal center line L when the coupler is angled to its maximum, i.e., 4-% inch, horizontally displaced position, thus avoiding wear between the yoke and the embraced draft gear 32 and bottom support plates 43 for the yoke.  
  In addition to the above enumerated advantages, the coupler and yoke arrangement comprising the invention also possesses the added advantage over the pres ent standard cross-key type coupler and yoke arrangement of requiring considerably less effort to manually displace the coupler from its normal centered position on the freight car such as is often performed by railroad yardmen in the coupling together of freight cars. FIGS. 4 and 5 illustrated the comparative conditions which obtain when the coupler is displaced, for example, through an angle of 5 from its normal centered position. It will be noted that, in the case of the standard cross-key type arrangement (FIG. 7 the contact point indicated at 108 between the coupler shank 62 and cross key 54, and between the coupler butt end 110 and front follower 30 as indicated at 112 produces an are R the longitudinal component c1 of which, representing the extent of compression of the draft gear 32 and therefore the amount of effort required to swing the coupler through the 5 arc, is of considerable magnitude amounting to a distance of about /32 inch. in the case of the improved coupler and yoke arrangement (FIG. 8) according to the invention, however, the contact between the coupler butt end 48 and the front follower produces an are R, as determined by the contact point 114, the longitudinal component (1&#39; of which is of much smaller magnitude, amounting to a distance of only about 7/32 inch which represents the extent of compression of the draft gear 32 by the coupler 10 when swung through an arc of 5. Thus, the amount of effort or force required to manually displace the standard cross-key coupler and yoke arrangement through an arc of 5 is more than twice that of the coupler and yoke arrangement according to the invention, the ratio of the relative amounts of effort required for such a coupler displacement being approximately 2.14 to 1. Moreover, this ratio increases to a slight extent as the arc of coupler swing movement is increased, it being approximately 2.23 to 1 for a 10 horizontal swing of the coupler, for example.  
  An added feature of the particular coupler and yoke construction according to the invention is that it is directly applicable to all freight cars presently equipped with standard horizontal key type yokes without any change required in the car structure itself. Thus, installation of the improved coupler and yoke construction in such existing freight cars is a relatively simple operation and can be accomplished at nominal cost. Also, because of the added strength of the coupler shank l4 and yoke 42 as compared to that of the present standard horizontal cross-key type coupler and yoke employed for Type E couplers, the coupler and yoke construction according to the invention is better suited to the increased tractive and starting effort which is characteristic of diesel locomotives and which permits the use of longer and higher tonnage trains.  
  FIGS. 9-l1 illustrate the application of the invention to a diesel locomotive pilot coupler 120 of cast steel and comprising a standard Type E coupler head portion 122 with a shank portion 124. Such couplers at present are generally provided with alignment control means either of the so-called solid type as disclosed in Metzger US. Pat. No. 2,832,476 or of the plunger type as disclosed in Metzger US. Pat. No. 2,754,978, the latter being the more efficient and more generally employed type. Such plunger type alignment control arrangements comprise a pair of plungers fitted laterally apart within the yoke head, and aligning wings projecting from the opposite sides of the coupler butt end on the coupler shank and adapted to engage with the plungers on lateral displacement of the coupler to effect a compression of the draft gear. Such a construction necessitates a comparatively long yoke head, added weight, and increased manufacturing cost such as the required cleaning and gaging of the steel castings to assure a proper fit. These disadvantages are obviated by the improved locomotive coupler and yoke arrange ment comprising the invention.  
  Referring to FIG. 9. the coupler is shown mounted on an end of a standard locomotive underframe with its shank portion 124 projecting into the end of the customary sill structure 126 of the locomotive between the laterally spaced side walls 128 and 130 thereof. The butt end portion 132 of the coupler shank 124 projects into and is housed within the head end portion 134 of a vertical plane cast steel yoke 136 between the upper and lower arms 138 and 140 thereof and between the side walls or struts 142 which tie the yoke arms 138, 140 together at the head end 134 of the yoke. As shown, the yoke 136 is mounted within the sill structure 126 in a position extending longitudinally thereof between the side walls 128, 130 of the sill structure for longitudinal movement therein, and it houses between its arms 138, 140 a draft gear assembly 144 received in draft gear pocket 146 in the sill structure 126 and comprised of a draft gear of any conventional type, as indicated by the crossed dot-dash lines 148, compressed between front and rear follower members 150 and 152 respectively. The follower members 150, 152 are of simple flatfaced form made from steel bar stock, and they are forced against front and rear stop lugs 154 and 156 on the sill structure 126 by the compressive force of the draft gear 148.  
  As is .customary in conventional locomotive coupler and yoke constructions, the coupler 120 is pivotally connected at its butt end 132 to the head end portion 134 of the yoke 136 by a vertically extending cylindrical steel pin 158 for the transmission of pulling forces to the yoke and for lateral swinging movement of the coupler relative to the yoke about a vertical pivot axis P located on the longitudinal center line A of the coupler 120 which center line, in the normal centered position of the coupler on the locomotive sill structure 126, coincides with the longitudinal center line L (FIG. 10) of the locomotive. The pivot pin 158 is located in the butt end portion 132 of the coupler shank 124 with its pivot axis P located a distance of about 4 inches, e.g., 3-31/32 inches in the particular case illustrated (FIG. 11), back from the flat central portion 160 of the butt end surface 162 of the coupler, and it extends through vertically aligned openings in the upper and lower arms 138 and 140 of the yoke head end 134 and through an opening in the coupler butt end 132. The pivot pin 158 is retained in place against dropping out of the yoke arms 138, 140 and coupler butt end 132 by the conventional bar-shaped retainer key (not shown) which extends across the underside of the lower yoke arm 140 and beneath the bottom end of the pivot pin, and is secured in place within support lugs (not shown) depending from the lower arm 140 of the yoke at its head end 134.  
  Draft movements of the coupler 120 are transmitted to the yoke 136 through the pivot pin 158, and by the yoke to the rear follower 152 in the conventional manner, to effect the compression of the draft gear 148 so as to absorb the pulling force on the coupler. Buffing movements of the coupler 120 are transmitted by the butt end surface 162 of the coupler shank 124 to the opposing flat front face 164 of the front follower 150, against which the butt end surface 162 abuts during such buffing impacts, to effect the compression of the draft gear 148 and absorption of the buffing forcev In accordance with the invention, the butt end surface 162 of the coupler 120, like that of the butt end surface 48 of the coupler in FIGS. 14, is formed of a particular contour which, in combination with the pivotal interconnection of the coupler and yoke and in opposed abutting cooperation with the flat-faced front follower 150, operates to provide a coupler and yoke assembly which not only is of considerably simpler and less expensive construction than the present standard plunger type coupler and yoke arrangements employed on locomotives but which at the same time affords an alignment control means which is practically just as efficient as that afforded by such plunger-type arrange ments. Referring to FIG. 11 in particular, the butt end surface 162 according to the invention is comprised of the relatively wide flat central portion 160 extending perpendicular to and centered about the longitudinal axis A of the coupler 120 and having a width in this particular case of approximately 4-/% inches, and tangentially joining at each side with corresponding convexly curved relieved contour side end portions or extensions 166 of appreciable lateral extent for rocking engagement with the front follower 150 on horizontal swing movement or angling of the coupler about its vertical pivot axis P. The curved side end portions 166 terminate. in this embodiment of the invention, at points D located about /32 inch back from the vertical plane B--B of the flat central surface portion 160 and spaced about 4-% inches from the longitudinal center line A of the coupler to provide, along with the flat central surface portion 160, an overall butt end surface width of about 9 inches. The curved side end portions 166 thus each have a lateral extent of about 2-% inches or 26 percent of the overall width of the coupler butt end surface 162. Together with its height or vertical depth of approximately 6% inches, the 9-% inch width butt end surface 162 provides a total bearing surface area of around 48 square inches for transmission of the buffing forces to the front follower 150 as compared to the approximate 27% projected square inch bearing surface area of the present standard plunger type locomotive pilot coupler and yoke arrangement. This represents an increase of approximately 74 percent in the effective bearing surface area of the coupler butt end for transmission of buffing forces to the front follower 150.  
  To afford smooth swinging action of the coupler 120 during the full range of the lateral displacement thereof. the convexly curved side end portions 166 of the butt end surface 162 are of a contour essentially constituted by a compound curved formed by a plurality of different radii. In the particular case illustrated (FIG. 11 these compound curve contour portions are each formed by several successive radii of about 1 inch, 34 inches, and l-% inches. for example, leading outwardly away from and tangent to the flat central portion 160 of the coupler butt end surface 162 and joining at its outer end with a short tangent outer end portion 168 which terminates at the points D which, as indicated above, are located approximately 15/32 inch back from the plane B-B ofthe flat central portion 160 of the butt end surface 162 and approximately 4 inches laterally to one side of the longitudinal center line A of the coupler. The outermost one of these three radii, i.e., the l-%111Cl1 radius, is centered at a point located approximately 1-31/32 inches back from the plane 13-3 of the flat central portion 160 of the cou pler butt end surface 162 and approximately 3 inches laterally to one side of the longitudinal center line A of the coupler. Also in the case of the particular coupler butt end construction 132 shown in FIGS. 9-11, it is provided with vertical side walls 170 of reverse curve contour which extend forwardly of the coupler from the outer terminal points D of the curved side portions 166 of the coupler butt end surface 162 and tangential join with and narrow down to the reduced width, for example, 8 inch width, parallel side wall portions 172 of the coupler butt end portion 132 at the re gion abreast of the pivot pin opening therein. Forwardly of the pivot axis P ofthe coupler shank 124, the side walls thereof gradually narrow down as indicated at 174 to meet with the slightly outwardly and forwardly tapering side wall portions 176 of the coupler shank which project outwardly from the yoke head end portion 134 and join with the coupler head 122.  
  As will be evident from FIG. 9, the head end portion 134 of the yoke 136 within which the butt end portion 132 of the coupler is received is entirely open at its opposite sides except for the relatively narrow and thinwalled tie struts 142 which join the two yoke arms 138, M0 together at their forwardmost ends. The open sides of the rearmost region of the yoke head end 134 thus provide room for the accommodation of the corners D of the butt end 162 of the coupler 120 when it swivels about its pivot axis P&#39; in service, so as not to be interfered with by the yoke. To this end, the rearward extents of the tie struts 142 terminate at points such as to permit the coupler 120 to swing to the required standard 19 laterally displaced position, as fragmentarily shown in dot-dash lines in FIG. 10 and as determined by the engagement of the coupler shank 124 with the striker casting 178 on the locomotive sill structure 126, without the side wall portions 170, 172 of the coupler shank striking against the tie struts 142. Also, like the coupler 10 in FIGS. l-4, the butt end portion 132 of the coupler 120 and its butt end surface 162 nearly fill the yoke head opening across its width between the side walls 142. Thus, in the particular case illustrated, the approximate 8 inch width dimension of the coupler butt end portion 132 across its side walls 172 amounts to around percent of the approximate 10 inch width of the yoke head opening, while the approximate 9-% inch overall width dimension of the coupler butt end surface 162 represents around percent of the width of the yoke head opening.  
  The locomotive pilot coupler and yoke arrangement shown in FIGS. 9-11, although of similarly simple and inexpensive construction as in the form of the invention shown in FIGS. 1-4, also provides at the same time a highly efficient alignment control means for the locomotive for preventing derailments thereof which is practically just as efficient as that afforded by present standard plunger-type locomotive pilot coupler and yoke arrangements. Referring to FIG. 10, it will be seen that a buffing force E applied to the coupler when laterally displaced 4- /2 inches at its coupling center point is applied by the butt end surface 162 of the coupler to the follower at a contact bearing located approximately 3-% inches laterally from the longitudinal center line L of the diesel locomotive. Thus, the force line e of the buffing force E passes through this contact point and is directed at a very slight angle in of around l-% to and intersects the locomotive center line L at a point (not shown) a considerable distance to the rear of the vertical pivot axis of the forward or adjacent truck thereof so that it exerts a lateral or derailing force component 1&#34; thereon which amounts only to approximately 0.03E. In comparison, buffing force applied to a standard plunger-type locomotive pilot coupler and yoke arrangement is applied to the front follower thereof at a contact bearing point located approximately 3-&#34;/a inches laterally from the locomotive center line L and the force line of such a buffing force passing through such contact point is directed at a similarly slight angle of around 1 to the center line L. Thus the difference between the lines of buffing force application to the locomotive at 4-/&amp; inches lateral coupler displacement is so insignificant that the alignment control action is practically just as effective with either coupler arrangement, it affording ample protection against derailment in either case.  
  As shown in FIG. 9, a slight clearance of approximately l/32 inch, for example, is provided between the flat central surface portion 160 of the coupler butt end surface 162 and the flat front face 164 of the front follower 150 in the normal centered position of the coupler 120 on the locomotive. This amount of clearance permits up to around 2 inches total free lateral displacement of the coupler 120 at its coupling line, i.e., 1 inch to either side of its normal centered position on the locomotive, for manual coupler positioning operations.  
  From the description above, it will be apparent from the locomotive pilot coupler and yoke arrangement comprising the invention and shown in FIGS. 9-11 pro vides a construction which, while affording alignment control action which is practically just as efficient as that provided by conventional plunger-type locomotive pilot coupler and yoke arrangements, at the same time embodies a yoke head which is comparatively short and simple in design and also results in an assembly of considerably reduced weight and comparatively low manufacturing cost.  
  The 3-% inch lateral displacement of the freight car couplers l and 62 shown in FIGS. and 6, and the 4 k inch lateral displacement of the engine pilot coupler 120 shown in FIG. 10, correspond to the degree of horizontal angling of these couplers which has generally been considered to be the minimum standard amount required for these couplers in their respective service applications. Within these ranges ofcoupler lateral displacement, the lines of buffing forces applied to the couplers 10 or 120 comprising the invention will in every case intersect the longitudinal center line of the vehicle at points located to the rear of the pivot center of the adjacent car or locomotive truck and thus provide the improved alignment control action in accordance with the purposes of the invention.  
  It will be evident from the above description of the embodiments shown in FIGS. 1-4 and 9-1] that the invention provides a railway coupler and yoke assembly which, although of simple and inexpensive construction, at the same time possesses substantially increased bearing surfaces during pull and buff operations in all positions of the coupler on the car with resulting reduced coupler wear and reduced maintenance cost and in addition provides highly efficient car alignment control means and improved safety against derailments. Moreover, the improved coupler is applicable to all freight cars having present standard type cross-key and yoke arrangements without the need of any modification to the car structure, and it also affords improved manual coupler displacement.  
 What is claimed is:  
  l. A coupler and yoke assembly for a railway vehicle having a sill structure with front and rear stop lugs and a draft gear assembly mounted in said sill structure between said stop lugs and including a front follower with a flat vertical front face, a yoke mounted in said sill structure and comprising vertically spaced arms extending longitudinally of said sill structure and housing said draft gear assembly, said yoke having a head portion located forwardly of said front stop lugs, a railway coupler having a shank portion with a butt end portion housed within said yoke head, a vertically extending cylindrical pin pivotally connecting said coupler shank at its butt end and to said yoke head for horizontal swiveling of the coupler relative to the yoke, said coupler having a vertical butt end surface opposed to said front follower for abutting engagement with the said flat front face thereof, said butt end surface comprising a flat central surface portion perpendicular to the longitudinal axis of the coupler and being of substantial width transversely of said coupler axis, said flat central surface portion tangentially joining at each side with corresponding convexly curved side end portions relieved away from said follower face, said curved end portions being adapted for rocking engagement with said front follower, on horizontal swiveling of the coupler, at contact points so laterally spaced from the longitudinal center line of the vehicle that a buffing force applied to the coupler, when the latter is in any horizontally displaced position up to at least 3-73 inches, is directed toward the center of the vehicle along a force line which passes through said contact points and intersects the said vehicle center line at a point rearwardly of the pivot center of the adjacent car truck of the vehicle.  
  2. A coupler and yoke assembly as specified in claim 1 wherein the said buffing force line extends at an angle of less than 3 to the longitudinal center line of the vehicle.  
  3. A coupler and yoke assembly as specified in claim 1 wherein the said curved side end portions of the coupler butt end surface are relieved at their outermost ends a distance of at least about 5/32 inch back from the plane of said flat central surface portion.  
  4. A coupler and yoke assembly as specified in claim I wherein the said coupler butt end surface has an overall horizontal width of at least about 7- /5 inches and its said flat central surface portion has a horizontal width of at least approximately 4-% inches.  
  5. A coupler and yoke assembly as specified in claim 3 wherein the said coupler butt end surface has an overall horizontal width of about 7 inches and the said flat central surface portion thereof has a horizontal width of about 5 inches.  
  6. A coupler and yoke assembly as specified in claim 5 wherein the said convexly curved side end portions of the coupler butt end surface are curved on a radius of about 5 inches.  
  7. A coupler and yoke assembly as specified in claim 1 wherein the said coupler is an engine pilot coupler and the horizontal extent of each of the said convexly curved relieved side end portions of the coupler butt end surface amounts to at least about 25 percent of the overall horizontal width thereof.  
  8. A coupler and yoke assembly as specified in claim 1 wherein the said coupler is an engine pilot coupler and its said butt end surface has an overall horizontal width of about 9-% inches.  
  9. A coupler and yoke assembly as specified in claim 8 wherein the said flat central surface portion of its butt end surface has a horizontal width of about 4-Vz inches.  
 central surface portion.