RAIL GRINDING MACHINE

Abstract: A railraod mounted grinding machine for maintaining the railhead profile of railroad track rails includes a plurality of grinding modules (38) mounted on an undercarriage (40). The undercarriage (40) is shiftably carried, by a track engaging platform, for side to side positioning of the grinding module (38) across the longitudinal axis of a rail (34). Each grinding module (38) is independently tiltable relative to the undercarriage (40).

Description: Technical Field This invention relates to rail grinding machines adapted to travel along railroad tracks and perform grinding operations on track rail surfaces. In particular, it pertains to a unique undercarriage for supporting grinding units on such rail grinding machines. Background Art Railroad track rails are subject to wear by the passage of trains over the rails. In particular, depressions in the upper surface of a rail may develop such that the rail head presents an undulating, corrugated surface. Moreover, the rail may develop burrs, or otherwise lose its symmetrical profile. Maintenance of smooth running surfaces on railroad track rails is important for reasons of safety, riding comfort, protection of the track, track bed and rolling stock, noise suppression, and reduced maintenance of the track and track bed. Grinding machines for maintaining railraod track rails in smooth, properly shaped condition are known. Such grinding machines generally comprise a plurality of rotatable grinding modules carried by a locomotive or the like in close proximity to the rail head surfaces of a railroad track. The grinding modules include rotatable, abrasive grinding stones that can be lowered into a position flush with the rail surface to grind and restore the rail surface to a smooth, desired profile. The grinding modules of such grinding machines include replaceable, abrasive grinding stones that are rotated about a grinding axis. The condition of the grinding stones directly affects the quality of grinding. More particularly, the grinding stones preferably present a generally flat, annular grinding surface, that is perpendicular to the axis of rotation of the grinding stones. While the grinding surface of a grinding stone is of course altered and worn in the grinding process, the grinding surface can be maintained essentially flat and perpendicular to the grinding axis by grinding only on the inner diameter of the stone. That is to say, placement of the annular grinding surface on the rail should be such that the rail sides do not extend beyond the inner diameter of the grinding stone. Moreover, it has long been considered preferable to have the grinding marks left by the grinding stone on the railhead be perpendicular to the rail longitudinal axis. Such perpendicular grinding marks are left when the grinding is done on the inner diameter of the stone. More precisely, perpendicular grinding marks are left on the railhead when the line of contact between the grinding stone and the railhead is along a diametrical line of the grinding stone, perpendicular to and intersecting the grinding axis of rotation. Grinding modules, with their attached grinding stones, can be tilted to accommodate grinding of railheads in planes other than the horizontal. Tilting of the grinding stone about a tilt axis oriented above and along the rail, however, shifts the line of contact of the grinding stone with the rail away from the diametrical line of the stone, and, depending on the angle, can shift the grinding contact away from the inner diameter of the stone. In short, tilting of the grinding stone, although necessary in order to shape the profile of a rail, can cause uneven wear of the stone and can leave grinding marks transverse to the perpendicular of the rail longitudinal axis. Another consideration when grinding rails to a desired profile is the presence of obstructions to the grinding stone. At road crossings, where the track intersects a highway for instance, wooden ties or rubber guards are typically brought into close proximity of the track rails to allow for smooth passage of wheeled vehicles across the track rails. Tilting of the grinding modules and grinding stones to shape the profile of the railhead can bring the grinding stones into interfering contact with the wooden ties or rubber guards. Finally, the grinding modules of rail grinding machines are typically raised into storage positions on the supporting locomotive or the like when not being operated to grind rails. The modules must therefore be lowered and properly oriented along the rail head prior to conducting grinding operations. The rail contacting support mechanisms for initially positioning and orienting the grinding modules are typically larger and more expensive than the size of wheels or other rail contacting support mechanisms required to maintain the modules in proper orientation once in place. In the past, the functions of orienting the grinding modules and supporting the grinding modules once in place have been combined into a single support device. While only a small area of the support device is subjected to continuous contact with the railhead, the entire device must be discarded when the device becomes worn. US-A-4,583,327 discloses a rail grinding apparatus with the features included in the first part of claim 1. As is particularly clear from Figure 9 of that document, when the grinding module is pivoted in order to grind the rail in a plane different from the horizontal, the line of contact between the grinding stone and the rail is shifted away from the diametrical line of the stone, which causes uneven ware of the stone and leaves the type of grinding marks transverse to the perpendicular of the rail longitudinal axis referred to above. The same applies to the rail grinding apparatus disclosed in GB-A-1,151,010 Figure 4 of which shows the line of grinding contact between the stone and the rail to be offset from the diameter of the grinding stone. SUMMARY OF THE INVENTION It is an object of the present invention to provide a rail grinding apparatus which avoids uneven ware of the grinding stone. This object is met by the invention as characterized in claim 1. The invention permits positioning the grinding head relative to the rail by horizontal positioning means in such a way that the line of contact between the grinding head can always be made to coincide with the diametrical line of the grinding head, as described further below in connection with Figure 12c of the drawings (in contrast to the prior art situation illustrated in Figure 12b). The invention further permits deliberately changing the line of contact between the grinding head and the rail in order to avoid obstructions typically occurring at road crossings (as described in detail with reference to Figure 12d). Brief Description of the Drawings Fig. 1 is a fragmentary, side elevational view of a rail grinding machine in accordance with the present invention with the parts removed for clarity; Fig. 2 is a front elevational view of a rail grinding machine in accordance with the present invention with parts removed for clarity, phantom lines depicting the grinding machine undercarriages in locked and raised positions; Fig. 3 is a fragmentary, front elevational view of one of the undercarriages of the rail grinding machine in accordance with the present invention, with parts removed for clarity, phantom lines depicting the undercarriage in the raised and locked position; Fig. 4 is a fragmentary, sectional view taken along line 4-4 of Fig. 3; Fig. 5 is a fragmentary, sectional view taken along line 5-5 of Fig. 3; Fig. 6 is similar to Fig. 3 but with the undercarriage partially disengaged with the rail and guide roller assembly included, phantom lines depicting the undercarriage in the rail engaging position; Fig. 7 is a fragmentary, side elevational view taken from the perspective of the line 7-7 of Fig. 6; Fig. 8 is similar to Fig. 7, but with the guide roller in the raised position; Fig. 9 is a sectional view taken along the line 9-9 of Fig. 1 with a grinding module shown in tilted configuration, phantom lines depicting the grinding module in an alternative tilted position; Fig. 10 is a sectional view taken along the line 10-10 of Fig. 9; Fig. 11 is similar to Fig. 10, but with the grinding module in the raised position; Fig. 12a is a schematic diagram of a grinding stone in grinding contact with the rail; Fig. 12b is similar to 12a, but with the grinding stone tilted from the horizontal; Fig. 12c is similar to Fig. 12b, but with the grinding stone shifted laterally; Fig. 12d is a schematic diagram of a grinding stone in tilted, grinding contact with a rail in the presence of an obstruction; and Fig. 13 is a schematic, plan view of a grinding stone in grinding contact with a rail. Detailed Description of the Drawings A rail grinding machine 20 in accordance with the present invention broadly includes main frame 22 supported by rail engaging wheels 24, operator cab 26, equipment compartment 28, and a plurality of grinding assemblies 30. The rail engaging wheels 24 support the rail grinding machine 20 on railroad track 32. The track 32 comprises a pair of rails 34 stretching across ties 36 of railroad bed 37. Each grinding assembly 30 broadly includes a plurality of grinding modules 38 individually mounted on a grinding assembly undercarriage 40. Each grinding assembly undercarriage 40 includes a grinding module support frame 42 attached to the rail grinding machine main frame 22 by fore and aft telescoping struts 44, 46. Each grinding module 38 is suspended from support frame 42 by fore and aft brackets 48 and 50. Referring in particular to Figs. 1, 3 and 6, fore and aft struts 44, 46 each include outer slide tube 52 pivotally coupled to main frame 22 by pivot pin 54, and an inner slide rod 56 slidably received within outer slide tube 52. The inner slide rod 56 includes lowermost base plate 58 attached to support frame 42 by bolts 60. Extensible boot 61 extends between outer slide tube 52 and the base plate 58 of the inner slide rod 56. Spreader piston and cylinder assemblies 62 extend between brackets 64 depending from the main frame 22 and the outer slide tube 52 of each fore and aft strut 44, 46. Each grinding module support frame 42 includes fore and aft U-shaped support members 66, 68 interconnected by uppermost, gauge side and field side frame members 70, 72. Side to side braces 74, 76, 78 extend between the gauge side and the field side frame members 70, 72. A pair of fore and aft, horizontal slide rods 80, 82 extend between gauge side and field side frame members 70, 72 for slidable support of each grinding module 38. Fore and aft undercarriage elevation piston and cylinder assemblies 84 extend between brackets 86 depending from main frame 22 and the fore and aft U-shaped frame members 66, 68. Each grinding module 38 includes grinding motor 90 supported on grinding module base plate 92, grinding shaft 94, and grinding stone 96. The grinding shaft 94 defines a center grinding axis 97 for each grinding module. Grinding stones 96 are annular grinding wheels each having lowermost grinding surface 98, inner stone diameter 100, and outer stone diameter 102. Shiftable, fore and aft, grinding module support rods 104, 106 extend upwardly from base plate 92 of each grinding module 38. A grinding module top brace 108 extends between each fore and aft, vertical, grinding module support rod 104, 106. The vertical, grinding module support rods 104, 106 are received within fore and aft, vertical, grinding module support sleeves 110, 112. Gauge side shroud 114 extends between sleeves 110, 112. The fore and aft grinding module support sleeves 110, 112 are pivotally connected to respective fore and aft brackets 48, 50 by pivot supports 116, 118. A grinding module elevation piston and cylinder assembly 120 extends between the forward pivot support 116 and top brace 108 of each grinding module 38. Referring to Fig. 9, each grinding module forward bracket 48 includes a tilt cylinder supporting brace 121. A grinding module tilting piston and cylinder assembly 122 extends between the brace 121 and the forward pivot support 116 of each respective grinding module. Again referring to Fig. 9, each of the fore and aft brackets 48, 50 are attached to a slide tube 124 carried by a respective fore or aft horizontal support rod 80, 82. As best seen in Figs. 10 and 11, a horizontal brace 125 extends between the slide tubes 124 of each pair of grinding module fore and aft support brackets 48, 50. A grinding module horizontal positioning piston and cylinder assembly 126 extends between each horizontal brace 125 and gauge side frame member 70. Grinding assembly supporting rail engaging wheel assemblies 128 are carried by each fore and aft U-shaped frame member 66, 68. Each wheel assembly 128 includes rail engaging wheel 130 rotatably attached to a respective U-shaped frame member 66, 68 by pillow blocks 132, and guide roller assembly 134. Wheels 130 include rail top engaging surface 136 and side rail engaging flange 138. The rail top engaging surface 136 of each wheel 130 is of a standard width, comparable to the width of the rail head. Each guide roller assembly 134 includes a set down roller 139 rotatably supported by opposed gauge side and field side bearing plates 140, 142. The bearing plates 140, 142 are pivotally mounted to support brackets 144, 146 that extend downwardly from each U-shaped frame member 66, 68. A guide roller assembly piston and cylinder assembly 148 extends between the field side bearing plate 142 of each guide roller assembly 134 and a respective stanchion 149 carried by each fore and aft U-shaped frame member 66, 68. Referring to Fig. 4, an upright securing flange 150 extends upwardly from each brace 74, 78. Securing flange receiving clevises 152 extend downwardly from main frame 22. Locking pins 154 are attached to locking pin actuating piston and cylinder assemblies 156 for shifting between securing flange engaging and securing flange clearing positions. In operation, grinding assemblies 30 of rail grinding machine 20, when not in use, are transported in raised, noncontacting relationship with the rails 34 of track 32, as depicted by phantom lines in Fig. 2 and Fig. 3. In particular, securing flanges 150 of grinding assembly undercarriage support frame 42 are secured within flange receiving clevises 152 of main frame 22 by locking pins 154, and the fore and aft struts 44, 46 are fully retracted. To commence guiding operations, locking pins 154 are shifted to their securing flange clearing position, as depicted in Fig. 1. The spreading piston and cylinder assemblies 62 are fully extended so as to tilt the individual grinding assemblies 30 inwardly towards the gauge side of rails 34. The grinding assemblies 30 are lowered towards railroad track 36 by extending the undercarriage elevation piston and cylinder assemblies 84. Prior to lowering the grinding assemblies 30 towards the track 36, the guide roller assemblies 134 are pivoted downwardly by extending the guide roller piston and cylinder assemblies 148. Accordingly, the set down rollers 139 are the first members of the grinding assemblies 30 to come into contact with rails 34. Referring in particular to Fig. 6, it will be appreciated that the width of the guide rollers 139 ensures engagement of the guide rollers 139 with the rails 34, regardless of where the grinding assembly 30 is positioned by the spreader cylinders 62. Contact of the guide rollers 139 with the rails 34 generally positions the grinding assemblies 30 in elevation. Once the guide rollers 139 have contacted the rail 34, the spreader piston and cylinder assemblies 62 can be retracted so as to shift the grinding assemblies 30 outwardly in a direction towards the field side of the rail 34. The rail engaging flange 138 of each wheel 130 will accordingly be brought into contact with the gauge side of rail 34. The guide roller piston and cylinder assemblies 148 can thereafter be retracted such that the weight of the grinding assembly 30 is borne by wheels 130. It will be understood, however, that an upward biasing force is exerted by the elevation piston and cylinder assemblies 86, 88 such that the entire weight of the grinding assembly 30 is not necessarily borne by the wheels 130. The spreader piston and cylinder assemblies 62 provide a constant biasing pressure to maintain the wheels 130 in engagement with rail 34. The top surface of rail 34 is ground by placing the grinding stone 96 directly over the rail 34, as depicted in Fig. 12a. The grinding axis of rotation 97 is centered along the longitudinal axis of rail 34. Referring to Fig. 13, the rail 34 is contained between the inner diameter 100 of grinding stone 96, and grinding contact between the stone 96 and rail 34 is along a diametrical line d of the grinding stone 96. As the grinding stone 96 is rotated as indicated by arrows R of Fig. 13, and is moved along the rail 34 in the direction of arrow A of Fig 13, the fine scratches S left on the rail 34 by the grinding action of the stone 96 are oriented perpendicular to the longitudinal axis of the rail 34. As depicted in Fig. 9, each grinding module 38 can be pivoted around pivot point P to position the grinding stone 96 at various tilt angles relative to the railhead. As shown in Fig. 12b, pivoting of the grinding module 38 around pivot point P, without shifting of the pivot point laterally in relation to the longitudinal axis of the rail 34, shifts the line of grinding contact between the stone 96 and rail 34 from the center, diametrical line d of the grinding stone to a point outboard of the diametrical line d. While tilting of the grinding module 38 to the orientation depicted in Fig. 12b enables shaping of the railhead, the resultant shifting of the line of contact between the grinding stone 96 and the rail 34 away from the diametrical line d of stone 96 causes uneven wear of the stone 96. Moreover, orientiation of the grinding stone 96 as depicted in Fig. 12b causes the scratches S left by the grinding operation to be transverse to the desired orientation perpendicular to the rail longitudinal axis. The grinding module 38, together with pivot point P, can be shifted laterally relative to the longitudinal axis of rail 34 by the extension and retraction of piston and cylinder assembly 126. More particularly, extension of respective horizontal positioning piston and cylinder assemblies 126 shifts the associated undercarriage 40 towards the field side of rail 34, the retraction of the piston and cylinder assembly 126 shifts the undercarriage 40 towards the gauge side of rail 34. Moreover, elevation of each individual grinding module 38 relative to the undercarriage 40 can be adjusted by the extension and retraction of respective module elevation piston and cylinder assemblies 120. Accordingly, the pivot point P can be shifted away from the center of rail 34, as depicted in Fig. 12c, and the grinding stone 96 can be lowered into contact with the rail 34 along a diameteral line d of the grinding stone 96. Referring to Fig. 12d, rail 34 is depicted in close proximity to an obstruction W. The obstruction could be a wooden support W placed along the rail at a highway crossing or the like. The presence of the obstruction W interferes with the placement of the grinding stone 96 relative to the rail 34. The capability to laterally shift the undercarriage 40 from side to side relative to the longitudinal axis of rail 34 provides a distinct advantage when grinding the rail 34 in the presence of an obstruction. In particular, referring to Fig. 12d, pivot point P can be shifted laterally away from the obstruction W thereby allowing the grinding stone 96 to be tilted to a greater tilt angle while still avoiding the obstruction, than would otherwise be attainable. Although the grinding contact with the stone 96 with the rail 34 is, in the instance depicted in Fig. 12d, moved away from the diametrical line d of the grinding stone 96, the amount of grinding required to be done in the presence of an obstruction is typically minimal.

Claims: An apparatus for grinding the rails of a railroad track, comprising: a support frame (42) supported by said rails (34) for movement along said track (32), a plurality of grinding modules (38) each having a grinding head (96) engageable with one of said rails (34), vertical positioning means (120) operably coupling at least one grinding module (38) to said support frame (42) for selectively raising and lowering the grinding module (38) relative to the respective rail (34) independently of the vertical position of the other grinding modules (38), and pivot means (122) operably coupling said grinding module (38) to said support frame (42) for pivoting the grinding module about a pivot axis (P) whereby its grinding head is selectively pivotable independently of the pivotal orientation of the other grinding modules (38), characterized by horizontal positioning means (80, 82, 124, 126) operably coupling said grinding module (38) to said support frame (42) for laterally shifting the grinding module (38) generally transversely to the longitudinal rail axis independently of the lateral position of the other grinding modules (38), said horizontal positioning means including slide rods (80, 82) extending transversely to the rail axis and being fixed to said grinding module support frame (42) for supporting slide tubes (124) secured to said grinding modules (38). The apparatus of claim 1, wherein each of said grinding modules (38) is suspended from a respective pair of slide rods (80, 82) by fore and aft brackets (48, 50) which are shiftably carried by said slide rods (80, 82). The apparatus of claim 2, wherein said horizontal positioning means include brace means (125) operably coupling respective ones of said fore and aft brackets (48, 50), and means (126) for shifting said brace means (125) relative to said slide rods (80, 82) whereby said brackets (48, 50) are shifted along said slide rods (80, 82). The apparatus of claim 2 or 3, including a grinding module base plate (92) extending between said fore and aft brackets (48, 50) and means (122) for pivoting said base plate (92) relative to said brackets (48, 50). The apparatus of claim 4, wherein said grinding module base plate (92) is coupled to said fore and aft brackets (48, 50) by a pair of opposed pivot support members (116, 118), said vertical positioning means including means (120) for raising and lowering said module base plate (92) relative to said pivot support members (116, 118).

Inventors: VIEAU, ROBERT G.
Applicants: LORAM MAINTENANCE OF WAY, INC.
Application year: 1988
Main classification: E01B31
IPC codes: E01B31