US 3606705 A
Description (OCR text may contain errors)
Sept 21, 1971 A. RIVOIRE RAIL GRINDER Filed July 30, 1969 2 Sheets-Sheet 1 e, m m v w A4 55W @VO/EE 4; (W Array/vars Sept. 21 1971 A. RIVOIRE 3,606,705
RAIL GRINDER Filed July 30, 1969 2 Sheets-Sheet a PRESSURE .-;SOURCE QEGULNYOR W424, cwywa #21014 United States Patent Filed July 30, 1969, Ser. No. 845,952 Int. Cl. 1324b 23/00 U.S. Cl. 51-178 Claims ABSTRACT OF THE DISCLOSURE A grinding head including a rotary grinding wheel is supported from a vehicle for movement along and in grinding engagement with a rail. A portion only of the weight of the grinding head is supported from the vehicle by fluid pressure means including an expansible chamber the volume of which varies with variations in the operating level of the grinding head. The unsupported weight of the grinding head is applied as operative pressure of the grinding wheel against the rail. A pressure control unit in communication with the expansible chamber automatically varies the pressure of fluid in such chamber as the grinding head deviates from a predetermined operating level to abruptly increase the operating pressure as the grinding head falls below said level and to abruptly decrease such pressure as the grinding head rises above such predetermined level.
This invention relates to improvements in Rail Grinders of the general type exemplified in the Speno et al. U.S. Pats. Nos. 2,779,141, of Jan. 29, 1957, and 3,358,406 of Dec. 19, 1967.
It is well known that through continued use over a period of time, the rails in a usual railroad track become worn in such a way as to form longitudinal waves or corrugations in the rail heads or portions thereof which are engaged by the train wheels. Where the amplitude of such waves or, in other words, the distance along the rail be tween the adjoining wave peaks, is greater than the diameters of the grinding wheels of the rail grinder, the floatingly supported grinder heads will tend to rise and fall with the waves, and thus will grind away as much material in the hollows between waves as on the peaks or crests of the waves, whereas it is desirable only to grind away the crests of the waves to achieve a level condition of the rail surfaces.
The above-mentioned Speno et al. Pat. No. 3,358,406 discloses a combination of a constant fluid pressure counterbalancing means for the floating grinder heads, in combination with a separate variable rate or resilient counterbalancing means therefor, operating together to engagement pressure between a given grinding Wheel and a rail, as the grinding wheel passes over a depression in the rail and to provide increased pressure of the grinding wheel against the rail in passing over a raised portion thereof.
It is a primary object of the present invention to achieve these same functions and advantages but by a simplified mechanism eliminating the separate resilient means and utilizing a novel fluid pressure actuated and controlled floating suspension for each grinder head, in which deviation of the grinder head below or above a predetermined operational position will actuate a pressure control means for causing the fluid actuated suspension to support a greater or lesser constant proportion of the weight of the grinder head and thereby abruptly to decrease the efficiency 0f the grinding action as the wheel passes over the hollows between waves and to abruptly increase the efficiency thereof and the rate of removal of metal as the grinding wheel tends to be raised in passing over the peaks of the waves. Such abrupt changes of operating pressure of the grinding wheel to new constant operating pressures serve more nearly to achieve a truly level surface on the rail than is possible where the deviation of the grinding wheel from its optimum operating level is resiliently or progressively opposed as by spring means or the like.
In order to promote an intelligent understanding of the invention, such as will enable those of ordinary skill in the art to practice it, a preferred embodiment of the invention is illustrated in the accompanying drawings and described in detail hereinafter. It will be understood that the drawings are by way of illustration only, and that the invention is intended to encompass all of the different variations and modifications which should be obvious to those skilled in the art to which the invention pertains.
Thus, in the accompanying drawings:
FIG. 1 is a general diagrammatic fragmentary side elevation of a vehicle equipped with the rail grinding equipment of the invention for grinding of the rails as the vehicle travels along them.
FIG. 2 is a fragmentary perspective view, on an enlarged scale, of a single grinder head and its associated fluid suspension as employed in the present invention.
FIG. 3 is a diagrammatic view of a single such grinder head and the fluid suspension system.
Referring now in detail to the accompanying drawings, the grinding mechanism of the invention is illustrated as including a car or vehicle V having flanged wheels 10 of conventional construction and arrangement by means of which it is supported and guided for movement along the parallel rails R of a conventional railroad track to grind the tread surfaces of the rails and if desired, their side faces, for the purpose of removing therefrom various irregularities normally created by wear and to substantially regenerate the tread surface and/ or side faces to rectilinear configuration longitudinally of the rails. The vehicle may be substantially similar to that disclosed in the Speno et al. Pat. 3,358,406.
Rigidly aflixed to and suspended beneath the frame of the vehicle V, are a plurality of pairs of horizontal transversely extending cross-bars 12 along which are adjustably disposed the longitudinally opposed slides 14, respectively, supporting the longitudinally opposed and aligned bearing 16 within which are journalled the trunnions 18 of a cradle or support 20 for a grinder head G. The trunnions and bearings are longitudinally aligned with the direction of movement of the vehicle along the rails R to permit adjusting of the cradles and grinder heads about the trunnions so that the track may be engaged and ground at any of various angles of tilt. Each grinder head comprises a preferably electrically driven grinder motor 22 having a vertical depending output shaft 24 at the lower end of which is carried a grinding wheel 26 of conventional abrasive material arranged so that its axially presented lower face is adapted for operative engagement with the rail R therebeneath.
The grinder head G is supported by the cradle 20 for tilting movement about the trunnions 18 so that the grinding wheel thereof may be correspondingly tilted (with respect to the rails to grind either the top surface or side surfaces thereof as desired.
The three grinder heads G of the gang shown in FIG. 1 are individually supported from the vehicle V in longitudinal alignment with each other over one of the rails R so that the grinding wheel of each grinder head G may operatively engage the surface of the rail head and may rise and fall with the Waves in the rail during passage thereover. For floatingly suspending or supporting the grinder head, the casing of the motor has afiixed thereto on opposite sides thereof the diametrically opposed cylinder 27 of a conventional fluid pressure means 28, here consisting of fluid actuated piston and cylinder units respectively defining expansible chambers 31. It will be understood that the pistons 29 of such units are fixedly supported within the cylinders at the upper ends of stationary piston rods 30, the lower ends of which are rigidly aflixed to the cradle 20.
For maintaining each grinder head in its desired angular adjustment about the horizontal trunnions 18, there is aflixed to the cradle an upwardly projecting quadrant plate 32 formed with an arcuate slot 34 concentric to the axis of the trunnions. An upwardly projecting lever arm 36 affixed to the cradle has a threaded stud 38 projecting and movable through this slot, whereby a nut threaded on the outer end of the stud may be tightened into frictional engagement with the quadrant plate to fix and maintain the angular position of the cradle and grinder head G.
Supplied into the expansible chamber 31 of each cylinder between the piston 29 and the upper end thereof, as for instance through the conduits 42 shown in FIG. 3, is a suitable actuating fluid, such as oil or other hydraulic liquid which is normally at a pressure to support only a predetermined part of the weight of the grinder head less than the entirety thereof, the balance or unsupported portion of the weight serving to press the grinding wheel 26 downwardly into operative engagement with the rail R therebeneath.
The construction and arrangement as thus far generally described is conventional and is similar to that disclosed in the Speno et al. Pat. No. 3,358,406 except that the resilient or variable rate counter-balancing means of that patent are completely eliminated.
In accordance with the present invention, the fluid pres sure means 28 for each grinder head is made to apply a varying supporting force to the grinder head depending upon variations in the vertical position of the grinder head from its intended level of operation. The arrangement is such that as the grinder head G and its grinding wheel 26 descend below the predetermined level of operation, the fluid pressure means 28 provides an increased supporting force to thus decrease the grinding or cutting action on the rail as the grinding wheel 26 passes over the hollows between waves. As the grinder head and wheel are raised in passing over the peaks of the waves, the said fluid pressure means supports a lesser proportion of the weight of the grinder head, thereby causing the grinding wheel to press harder against the rail and remove material therefrom at an increased rate.
For these purposes, the fluid supply line 42 which communicates with and carries the pressurized fluid into the expansible chambers at the upper ends of the piston and cylinder units 28, communicates, at times, with a completely enclosed tank 44 containing a reservoir of oil or hydraulic fluid 46 in its lower portion, and above which is a cushion 48 of pressurized air or gas. A conduit 50 places the upper end of the tank and the air cushion therein in communication through a conventional adjustable pressure regulator 52 with the pressurized air supply, exemplified in part by the pipe section 54.
By regulating the pressure of air supplied into the upper portion of the tank 44, it is possible to impose a similar pressure on the liquid 46 which is supplied into the upper ends of the piston and cylinder units, the pressure preferably being regulated to support a predetermined portion only of the weight of the grinder head G, whereby the remaining weight thereof may serve to thrust the grinding wheel into operative engagement with the rail.
For increasing the pressure of the fluid acting within the cylinders, responsive to downward movement of the grinding head from a predetermined level and for decreasing such pressure as the grinding head moves upwardly above said level, there is provided a pressure control unit in the form of a cylinder block 56 defining therein a two-diameter pressure increasing cylinder 58 and a two-diameter pressure reducing cylinder 60. Differential pistons 62 and 64, respectively, are slidably disposed in the respective cylinders 58 and 60. Such pistons normally abut against stop means 66 and 68, which, in
4 the preferred embodiment, comprise the annular shoulders at the juncture of the large and small diameter ends of each cylinder.
The upper ends of the cylinder or cylindrical chambers are in constant communication through a passage 70 and line 72 with the air pressure regulator 52 so that the pistons 62 and 64 within the respective cylinders will be exposed at all times to the constant air pressure supplied by said regulator. The lower ends or portions of the respective differential cylinders communicate through the passage 74 and hydraulic line 76 with the hydraulic conduit 42 at a location of the latter which is between the fiuid pressure means 23 and the tank 44. Also located in the oil supply line between the tank 44 and the juncture of the line '76 with the conduit 42 is an isolating valve 78, preferably of the solenoid controlled type, which may be closed to isolate the fluid pressure means 28 and the lower ends of the cylinders of the control unit 56 from the tank 44 and the air pressure regulator, thereby entrapping a predetermined quantity of oil in the hydraulic units and lower chambers and their interconnecting lines or conduits. Thus when the solenoid valve 78 is in its normal closed position, the conduit 42, line 76 and passage 74 serve as a means for providing a normally closed path of communication between each expansible chamber 31 and the lower ends of cylinders 53 and 60.
It will be understood that each grinder head will have its own control unit and system associated with its respective piston and cylinder units or fluid pressure means 28, whereby variations in the level of one grinder head will not affect the position of another grinder head. Manifestly, the grinder heads, control units and associated parts may be the same for each grinder head as is illustrated in FIG. 3.
OPERATION In the use of the invention, which is believed to be obvious from the foregoing description, the grinder heads G of a given gang will be positioned over and in operative engagement with one of the rails R which is being traversed by the vehicle V. The solenoid valve 78 is opened to permit communication between the tank 44 and the expansible chambers 31 of the fiuid pressure means 28 of the grinding head. The adjustable fluid pressure regulator 52 is adjusted to supply air to the tank 44 and thus transmit oil pressure to the expansible chambers 31 in an amount suflicient to support a portion only of the weight of the grinder head, whereupon the latter will be lowered into engagement with the rail to be ground. After each grinding head is lowered to bring its grinder wheel 26 to rest against the rail, the pressure regulator 52 .for each grinder head is adjusted to cause the fluid cylinder and piston units of the grinder head to support a desired proportion of the weight of the grinder head, so that the remaining unsupported weight may be utilized to urge the grinding wheel into operative engagement with the rail, at a pressure which is selected to secure an optimum grinding action on the rail R, when the grinding wheel is at a predetermined operating level.
With the grinder head thus positioned at its predetermined operating level, the solenoid valve 78 is then closed in obvious manner to isolate the piston and cylinder units or fluid pressure means 28 and the lower ends of the two diameter cylinders 58 and 60 from the tank 44, thereby entrapping a predetermined volume of fluid in these parts and in the closed path of communication between them, at a pressure equal to that discharged from the fluid pressure regulator. Thus, when the grinder head is supported at its desired predetermined level, as above described, the pressure in the upper and lower ends of the two-diameter cylinders 58 and 60 of the control unit will be equal. Accordingly, the equalized fluid pressures on opposite sides of the differential piston 62 of cylinder 58 will force said piston downwardly and normally maintain it in a position of rest with its larger diameter portion in abutment with the upwardly facing annular shoulder or stop means 66 at the juncture of the different diameter portions of the cylinder. On the other hand, the equalized fluid pressures in the opposite ends of the other control cylinder 60 will exert a differential force urging and maintaining the enlarged lower end of the differential piston 64 in abutting stationary position in engagement with the downwardly directed annular shoulder or stop means 68 at the junction of the different, diameter portions of the cylinder.
As the vehicle V with its several grinder heads G moves along the rail R, as each grinding wheel 26 passes over a depressed portion of the rail between wave crests, the ensuing downward movement of the grinder head will force hydraulic fluid from the expansible chambers 31 back through the conduit 42, line 76 and passage 74 into the lower end of the control cylinder 58. Such displaced fluid obviously will not affect the differential piston 64 since its enlarged lower end is already in abutment with the stop shoulder 68. However, such displaced fluid will raise the differential piston 62 from the stop shoulder 64 and urge its enlarged upper end upwardly into the large diameter end of the control cylinder 58. Though the pressure in the upper end of the cylinder will remain constant, being thus maintained by action of the regulator 52, it will be apparent that, because of the differences in diameter between the upper and lower portions of the differential piston 62 exposed to the fluid pressure, a substantially greater fluid pressure is required in the lower end of the cylinder than in the upper end thereof to initiate a raising or unseating of the piston from its stop means 66. During the upward displacement of the piston, the pressure which acts upon it in the upper end of the cylinder will be maintained constant by action of the regulator 52, thereby to maintain a constant increased fluid pressure in the lower end of the cylinder as long as the piston is raised. Such increased constant fluid pressure is transmitted to the expansible chambers 31 of the cylinder piston units and thus enabling the same to support a greater proportion of the weight of the grinder head than when the piston is in its normal seated position and thereby to decrease the grinding pressure of the grinding wheel on the rail.
On the other hand, when the grinding wheel 26 of each grinding head G passes over a raised portion of the rail, as for instance, in passing over the peak of a longitudinal wave therein, the resultant raising of the grinding head and its supporting cylinders with respect to the pistons therein, will enlarge the expansible chambers 31 to draw the hydraulic fluid from the enlarged lower end of the low pressure responsive cylinder 60, thus reducing the pressure therein. The differential piston 64 will accordingly move downwardly away from its stop shoulder, being urged into engagement with the hydraulic fluid by the constant air pressure maintained by the regulator in the upper end of the cylinder. The piston 62 will remain stationary, in engagement with its stop means 66.'Because of the differences in area of the respective upper and lower ends of the differential piston 64, which are exposed to the fluid pressures within their respective cylinder ends, as long as the piston 64 thus remains unseated from its stop shoulder '68, due to operation of the grinding wheel over a high portion or crest of the wave in a rail, a substantially decreased but constant portion of the weight of the grinder head will be supported by the fluid pressure within the expansible chambers 31, as will be readily apparent.- However, as soon as the grinding head G is restored to its predetermined level of operation on the rail, the differential piston 64 will be reseated against its stop means 68 and thus will maintain the oil within the expansible chambers 31 at the upper end of the cylinders 27 at a normal pressure to support the desired and predetermined portion of the weight of the grinder head and thus to cause the same to exert the desired operating pressure against the rail.
It is to be particularly noted that the action of the invention is such that, when a grinding wheel deviates in either direction from its predetermined level of operation, the resulting pressure change within its associated expansible chambers is in the form of an abrupt shift to a constant higher or lower pressure, this serving more nearly to achieve a level surface on the rail than would be the case were the pressure shift a gradual or progressive one.
Having thus described my invention, I claim:
1. A rail grinder of the class which includes a vehicle guided for movement along a rail, a grinding head having a drive motor and a rotary grinding wheel below and driven by the said motor in operative engagement with an upwardly presented portion of the rail to be ground, fluid pressure means for supporting a portion only of the weight of said grinder head from the vehicle, the balance of said weight constituting the operating pressure of the grinding wheel against the rail, said fluid pressure means comprising an expansible chamber, the volume of which varies with variations in the operating level of said grinding head, and fluid in said chamber at a predetermined constant pressure when said grinding head is at a predetermined operating level with respect to the rail being ground, the combination with said fluid pressure means of a pressure control unit communicating with said expansible chamber and responsive to deviation of said grinding head from its predetermined operating level for automatically changing the pressure of fluid in said chamber to and maintaining it at a new constant pressure throughout any such deviation.
2. A rail grinder as defined in claim- 1, wherein said pressure control means comprises a pressure reducing means for decreasing the fluid pressure in said chamber responsive to movement of the grinding heat above said predetermined level.
3. A rail grinder as defined in claim 1, wherein said pressure control means comprises a pressure increasing means for increasing the fluid pressure in said chamber responsive to movement of the grinding head below said predetermined level.
4. A rail grinder as defined in claim 1, wherein said pressure control means comprises a pressure reducing means for decreasing the pressure in said chamber when the grinding head moves above said predetermined level, and a pressure increasing means for increasing the pres sure in said chamber when the grinding head moves below said predetermined level.
5. A rail grinder as defined in claim 1, wherein said pressure control unit is formed to provide a two-diameter cylinder, a differential piston being slidably disposed in said cylinder, stop means in said cylinder limiting the movement of said piston into the small diameter end of the cylinder, means providing a normally closed path of communication between said expansible chamber and one end of said cylinder, a predetermined quantity of liquid entrapped within and fully occupying said chamber, said closed path and last mentioned end of said cylinder, said liquid being at a predetermined pressure for supporting a predetermined portion of the weight of said grinding head, when said grinding head is positioned at an optimum operating level with respect to the rail being ground, a source of fluid communicating with the other end of said cylinder, and means for maintaining said fluid at a constant pressure substantially equal to said predetermined liquid pressure, whereby in the said predetermined position of the grinder head said differential piston normally will be seated against said stop.
6. A rail grinder as defined in claim 5 including valve controlled means for temporarily interconnecting the said expansible chamber and said source of fluid for equalizing the pressures therein.
7. A rail grinder as defined in claim 1 wherein said pressure control unit is formed to provide a two-diameter pressure reducing cylinder, a differential piston being slidably disposed in each said cylinder, stop means in each cylinder limiting the movement of said pistons into the small diameter ends of the cylinders, means providing a normally closed path of communication between said chamber and the small diameter end of said pressure increasing cylinder and between said chamber and the large diameter end of said pressure reducing cylinder, a predetermined quantity of liquid entrapped within and fully occupying said expansible chamber, said closed path and the last mentioned ends of said control cylinders, said liquid being at a predetermined pressure when both said pistons seat against their respective stop means with said grinder head positioned at its said predetermined operating level, a source of fluid communicating with the ends of the respective cylinders opposite to their said first mentioned ends, and means for maintaining saidfluid at a constant pressure equal to said predetermined liquid pressure.
8. A rail grinder as defined in claim 7 including valve controlled means for equalizing the pressure of the liquid and fluid at the opposite ends of each cylinder when said grinding head is partially supported on the rail at its predetermined operating level.
9. A rail grinder as defined in claim 8 in which said fluid is a gas and said means for maintaining the fluid at a constant pressure equal to said predetermined liquid pressure is a variable pressure regulator, a pressurized source of gas communicating with said variable pressure regulator.
10. A rail grinder as defined in claim 1, wherein said pressure control unit is formed to provide a two-diameter pressure increasing cylinder and a two-diameter pressure reducing cylinder, a differential piston being slidably disposed in each said cylinder, stop means in each cylinder limiting the movement of said piston into the small diameter ends of the cylinders, means providing a normally closed path of communication between said chamber and the small diameter end of said pressure increasing cylinder and between said chamber and the large diameter end of 8 said pressure reducing cylinder, a predetermined quantity of fluid entrapped within and fully occupying said expansible chamber, said closed path and the last mentioned ends of said control cylinders, said fluid being at a predetermined pressure when both said pistons engage their respective stop means and said grinder head is positioned at its predetermined operating level, a source of fluid communicating with the ends of said respective cylinders opposite to said first mentioned ends, and means for maintaining the fluid from said source at a constant pressure equal to said predetermined pressure, whereupon movement of the grinding head below its said predetermined level will cause the opposing fluid pressures in said high pressure control cylinder to displace the piston of 1 said cylinder into the enlarged end thereof to produce an increased constant fluid pressure within said expansible chamber to support an increased constant portion of the weight of said grinder head, and movement of the grinder head above said level will permit the fluid of said predetermined constant pressure to transmit through the piston of its associated cylinder a decreased constant fluid pressure to said expansible chamber for supporting a decreased constant portion of the weight of said grinding head.
References Cited UNITED STATES PATENTS 2,197,729 4/1940 Miller 51178 2,779,141 1/1957 Speno et al. 5l178 3,358,406 12/1967 Speno et al. 51-178 FOREIGN PATENTS 802,1 13 1958 Great Britain.
975,483 1964 Great Britain.
823,456 1949 Germany. 1,263,568 1960 France.
WILLIAM R. ARMSTRONG, Primary Examiner