Patent Description:
Railway vehicles operate by using railway wheels which are guided and supported by rails affixed to the ground or other structures. Railway vehicle wheels are typically part of a wheel set which includes, at a minimum, a pair of wheels, an axle, and bearings. In addition, wheel sets are typically mounted on the bottom of a railway vehicle using a bogie or truck which, for example, may support four or more wheels. During operation of a railway vehicle (such as locomotives and railroad cars), their wheels become worn due to their contact with the rails upon which they ride. This wear often increases the risk of train derailment and may accelerate wheel wear or otherwise adversely affect the running characteristics of the wheels and railway vehicles. For example, the wheels of railway vehicles may, with wear, develop flat areas on their circumferences. Such wear often causes a bump or vibratory rotation of the worn wheel against the rail. Moreover, the contours of the wheels of railway wheel sets may be the subject to international standardization. Thus, especially with high-speed trains, the wheels should be periodically reprofiled to reduce or minimize worn areas and resultant bearing or bogie loads of the rail vehicles and the concomitant wear of rail surfaces.

Railway wheel sets may be reprofiled or trued with stock removal carried out, for example, by a turning or milling process. Thus, for example, peripheral milling machines, which are adapted to remove metal by feeding a workpiece through the periphery of a rotating circular cutter (such as a milling cutter), are often used. Typically the wheel set is cut by mechanically constraining the wheel set relative to its center of rotation and rotating the wheel set relative to a cutter to true the periphery of the wheel. However, supporting the wheel set to maintain a fixed center of rotation while rotating the wheel set or cutter to cut the wheel may be challenging. Alternatively, the milling cutters may be locked into a fixed radial position relative to the wheel set while allowing the centerline of the wheel set to move radially during the cutting process. However, locking the cutter into such a fixed radial position on the wheel set is also challenging and typically requires access to the centering holes on the ends of the axle. <CIT> discloses an underfloor lathe for machining the peripheral surface of a wheel of a railway vehicle in assembled condition, wherein a wheel set is mounted on driven supporting rollers, having a tracer lever arranged to be connected to the rotating wheel set axle or to its non-rotating bearing box and to transmit the movement of the wheel set axle by means of a feeler to a lifting device for the supporting rollers in such a manner that the distance between axle axis and tool edge remains always substantially the same. By means of this arrangement, the vertical component of the eccentric movement of the wheel set axle is transmitted immediately and directly to the lifting mechanism of the driving rollers, so that in the case of an upward movement of the axle, the lifting device and hence the driving rollers make an oppositely directed movement of equal magnitude. With stationary tool edge, a round-running profile is produced, despite eccentric or non-circular wheel.

It is therefore an object of this invention to provide a railway wheel truing or shaping system which is useable without physically locking into place the centerline of the wheel set, or locking the cutter into a fixed radial position relative to the wheel set centerline.

It is another object of this invention to provide a process for truing or shaping a railway wheel contour which allows for the movement of the center of rotation of the wheel or wheel set.

It is yet another object of this invention to provide a process for truing or shaping the contour of a railway wheel which compensates for movement or changes in the position of the center of rotation of the wheel and/or wheel set during the cutting process.

In accordance with aspects of the invention, there is provided a method of reprofiling a wheel set of a railway vehicle according to independent claim <NUM>.

The material includes rotating a wheel set while allowing a center of rotation of a wheel of the wheel set to move vertically and cutting the wheel to mill a profile on the wheel while moving the cutting tool towards the center of rotation of the wheel. The method also includes determining changes in position of the center of rotation while cutting the wheel and moving the cutting tool towards the center of rotation of the wheel based upon the changes in position of the center of rotation. The cutting tool may be moved towards the center of rotation of the wheel towards and to a constant distance. The constant distance may correspond to the desired radius of the reprofiled wheel.

The method involves diposing a wheel set on rollers; determining a center of rotation of a wheel on the wheel set; rotating the wheel; determining a desired constant distance between a cutting tool and the center of rotation of the wheel; activating a cutting tool on the wheel to mill a profile on the wheel and allowing the center of rotation of the wheel to move relative to the rollers; and moving the cutting tool towards the desired constant distance between the cutting tool and the center of rotation of the wheel to help facilitate maintaining the desired constant distance during the cutting process. The method also includes tracking or monitoring changes in position of the center of rotation of the wheel after the wheel has been rotated and the cutting tool has been activated, and may include measuring a distance corresponding to the distance between the rollers and the center of rotation. The measured distance may include both the vertical and horizontal distances between the one or more rollers and the center of rotation. The cutting tool may be moved in response to the measured distance. The position of the center of rotation of the wheel may be tracked or monitored using a tracking device. The method may be performed when the wheel set is removed from the railway vehicle and/or the wheel set is attached to a bogie.

In another aspect, the invention encompasses an apparatus, according to independent claim <NUM>, for reprofiling a wheel set of a railway vehicle. The apparatus includes a station having rollers configured to support the wheel set while allowing a center of rotation of the wheel to move relative to the rollers. A cutting tool is operatively connected to the station and is moveable relative to the rollers and into a position to cut or mill a profile onto a wheel of the wheel set. A tracking device is connected to the station to sense the position of the center of rotation. A control system is connected to the station and the tracking device. The control system is configured to control the position of the cutting tool relative to the center of rotation of the wheel and to facilitate movement of the cutting tool, and move the cutting tool, to help maintain a constant distance from the center of rotation.

The control system may be configured to calculate a distance corresponding to the distance between the rollers and the center of rotation of the wheel, and configured to move the cutting tool based on such distance. The control system may be configured to receive information from the tracking device to track the center of rotation of the wheel after the cutting tool is activated. The station may include a mechanism configured to contact the wheel set and maintain the wheel set on the rollers while allowing the center of rotation of the wheel to move relative to the rollers. The station may be configured to support a wheel set attached to a bogie.

The apparatus may include a second cutting tool operatively connected to the station. The second cutting tool is moveable relative to a second set of rollers and positioned to cut or mill a profile onto a second wheel of the wheel set. A second tracking device is connected to the milling station to sense the position of a center of rotation of the second wheel. The control system may be operatively connected to the second tracking device and be configured to control the position of the second cutting tool relative to the center of rotation of the second wheel to move the second cutting tool towards a constant distance from the center of rotation of the second wheel, and to facilitate maintaining the constant distance during the cutting process. A single station may be configured to cut multiple wheels and wheel sets according to the procedures described herein. Also, multiple stations may be used simultaneously to reprofile multiple wheels simultaneously. Each station may be controlled by the same or a separate control system.

The present invention will be more fully understood by reference to the following detailed description thereof, when read in conjunction with the attached drawings, wherein like reference numerals refer to like elements, and wherein:.

Referring to <FIG>, a system for reprofiling the wheels and wheel set of a railway vehicle is shown. The system <NUM> includes a station <NUM> which supports a wheel set <NUM> of a railway vehicle. The wheel set <NUM> includes a pair of wheels <NUM>. Wheels are supported each on rollers <NUM>, one or more of which may be drive rollers. Each end of the wheel set <NUM> is positioned using a hold down mechanism <NUM>. The hold down mechanisms <NUM> allow the center of rotation of the wheel set and wheels to move in the vertical and/or horizontal directions. Accordingly, the wheel set hold down mechanisms <NUM> do not chock the wheel set in a fixed position relative to the station <NUM> and/or rollers. A pair of tracking devices <NUM> are incorporated into the station <NUM> and are used to measure and track the movement of the wheel set <NUM> and its center of rotation of each wheel <NUM>. A control system <NUM> is included within the system and operatively connected to the drive rollers to drive and rotate the same when desired. Activation of the drive rollers will cause the wheel set <NUM> and wheels <NUM> to rotate.

Referring still to <FIG>, the control system <NUM> is also operatively connected to the cutters <NUM> to activate the same. The control system <NUM> is also coupled to the tracking devices <NUM> in order to track the position and change of position of the center of rotation of the wheels <NUM> and wheel set <NUM> when the wheels rotate during the cutting process. The system also includes profile measurement devices <NUM> (shown in <FIG>) which are operatively connected to the control system <NUM>. The profile measurement devices <NUM> measure the outer profile of the wheels <NUM> and are integrated and/or connected to the control system <NUM> to calculate the center of rotation of the wheels <NUM> and wheel set <NUM> including prior to activation of the cutters <NUM>. The cutters <NUM> are moveable to contact the wheels <NUM> to mill a profile onto the outer circumference of the wheels. The control system <NUM> controls the movement of the cutters <NUM> and their speed and torque. The cutters <NUM> are each connected to a carriage assembly mechanism <NUM> (see <FIG>) which allows the cutters to move, preferably, in both the vertical and horizontal direction. Although, however, the system may operate by moving a cutter <NUM> in only the vertical direction.

A simplified representation of the system <NUM> in accordance with the invention is shown in <FIG>. The wheel hold down mechanisms <NUM> contact the outer ends of the wheel set <NUM> to maintain the same on the rollers by applying a downward force on the wheel set <NUM> while allowing the wheel set <NUM> to move vertically and/or horizontally so that the center of rotation of the wheels <NUM> and wheel set <NUM> may move relative to the station <NUM>. The hold down mechanisms <NUM> are part of an overhead bridge assembly <NUM> which is moveable along a pair of tracks <NUM> parallel to the direction of rotation of the wheel set <NUM>. This system allows the overhead bridge assembly to move away from the rollers <NUM> to place the wheelset thereon, for example, using an overhead crane (not shown).

Referring now to <FIG>, a simplified schematic representation of certain components of the system for reprofiling a wheel set of a railway vehicle is shown. Although one wheel is shown in <FIG>, multiple similar or identical components may be used to shape the profile of multiple wheels. Moreover, each component may be controlled by the same control system <NUM>. The wheel set <NUM> is mounted on the station <NUM> by placing each wheel <NUM> on a set of rollers <NUM>. One or more of the rollers <NUM> may function as drive rollers to rotate the wheel <NUM>, for example, in the counterclockwise direction. The cutter <NUM> is moveable in the vertical and horizontal direction and relative to the rollers <NUM> and the station. Each wheel <NUM> and wheel set <NUM> has a center of rotation <NUM>, which as discussed herein, is calculated prior to activation of the cutter and prior to reprofiling the profile of the wheel <NUM>. A profile measurement system, as also described below, is used to measure the profile of the wheel <NUM> and calculate the center of rotation <NUM>. The control system is operatively connected to the cutter <NUM> to move the cutter in the horizontal and vertical direction via the carriage assembly mechanism controlling the position of the cutter. Based upon the location of the center of rotation <NUM>, the control system determines a desired constant distance <NUM> between the center of rotation of the wheel <NUM> and the center of rotation of the cutter <NUM>. This desired constant distance <NUM> represents the desired radius of the wheel and should be maintained throughout the cutting cycle and the rotation of wheel <NUM> by the one or more drive rollers. The control system <NUM> facilitates maintaining the constant distance <NUM> between the center of rotation <NUM> and cutter <NUM> by controlling the position of the cutter as the position of the center of rotation <NUM> changes during the rotation of the wheel <NUM>. In this way, the cutter may be maintained at the desired constant distance from the center of rotation of the wheel. And, the wheel can be cut to a constant radius.

Referring to <FIG>, tracking device <NUM> is used to determine the change of position of the center of rotation <NUM> as wheel <NUM> rotates. Tracking device <NUM>, may contact the outer portion (or other area) of the wheel set <NUM> near the center of rotation <NUM> so as to track the movement of the center of rotation <NUM> in the vertical and horizontal direction. The tracking device <NUM> may also track the movement of the wheel set <NUM> in the direction parallel to the centerline of the axle (i.e., side-to-side on the machine). This information is used to keep the cutters <NUM> aligned with the wheel <NUM> in the event that the wheel set <NUM> moves in the side-to-side direction within the limited axial float of the drive rollers. This may be used in lieu of an axial guidance system which is intended to prevent that same side to side movement of the wheel set <NUM>. The tracking device <NUM> transmits a signal to the control system representative of the change of position of the center of rotation <NUM>. The control system <NUM> may then calculate the change in position of the center of rotation <NUM> relative to the rollers (or any other fixed location on the station <NUM>) and calculate distance <NUM> (<FIG>) between the station <NUM> and the center of rotation <NUM>. Based upon the distance <NUM> as calculated by the control system <NUM>, and upon the change in the position of the center of rotation <NUM>, the control system <NUM> will move cutter <NUM> in the vertical and horizontal direction, if necessary, to maintain constant distance <NUM> (<FIG>) between the center of rotation <NUM> and the cutter <NUM>.

The process of cutting the wheel commences by the control system <NUM> activating a drive roller to rotate the wheel and wheel set. The drive roller, for example, may rotate the wheel one rotation in about seven minutes during which time the cutter cuts the outer profile of the wheel. The system thus allows for a slower more controlled cut of the wheel, as compared to a high speed rotation turning process. Tracking device <NUM> may contact the wheel set axle <NUM> directly or any part of the system that is coupled directly to the movement of the axle's center of rotation <NUM> such as the hold down system <NUM> (not shown). The tracking device <NUM> may sense movement of the outer position of the axle <NUM> which corresponds to a change in position of the center of rotation <NUM>. The control system may then calculate the change of position of the center of rotation <NUM> to adjust the position of the cutter <NUM>.

Referring now to <FIG>, as the wheel <NUM> continues to rotate counterclockwise by drive rollers <NUM>, the cutter <NUM> will continue to cut or mill a profile into the outer periphery of the wheel <NUM>. Thus, a newly cut surface of the profile of the wheel <NUM> will move counterclockwise as the wheel <NUM> turns such that the cut profile of the wheel <NUM> will contact the drive roller <NUM> at location <NUM>. As this occurs, the center of rotation <NUM> of the wheel <NUM> will move towards the roller <NUM> and towards location <NUM>, namely, downwardly and to the right. As this occurs, the tracking device <NUM> will sense the outer position of the axle (and changes thereto) and thus the center of rotation <NUM> of the wheel <NUM> and wheel set <NUM>. The control system will calculate the distance <NUM> (as shown in <FIG>) and adjust the position of the cutter <NUM> to maintain the cutter at constant distance <NUM>. The distance moved by the cutter will be the difference between the constant distance <NUM> and the calculated or measured distance <NUM>, as shown in <FIG>.

Referring now to <FIG>, as the cutter continues to cut the wheel <NUM>, the tracking device <NUM> continually tracks the center of rotation <NUM> and senses the change in position of the center of rotation <NUM> so that the control system may adjust the position of the cutter <NUM> to maintain the constant distance <NUM> between the center of rotation <NUM> and the cutter <NUM>. When the wheel <NUM> completes a full rotation such that the cutter <NUM> cuts a profile into the entire circumference of the periphery of the wheel <NUM>, the resultant profile facilitates a circular profile of the wheel. If desired, the profile measurement system may re-measure and calculate the profile of the wheel and one or more additional cutting cycles or rotation may be performed. The cutting of a single wheel profile as shown and described with reference to <FIG>, may be performed on multiple wheels of wheel set on a single station (as shown in <FIG>).

Referring to <FIG>, the station <NUM> includes rigid base platform which supports left hand and right hand column assemblies <NUM>, the cutting system, hold down mechanisms <NUM>, wheel profile measurements device or system <NUM> and tracking device <NUM>. Rail tracks may be incorporated into the system for transport of the wheel set (as shown in <FIG>). The station includes a pair of two-axis moveable carriage assemblies <NUM> as shown in <FIG>, each of which moves the cutter <NUM> and a profile measurement device <NUM>. A carriage <NUM> is included in each carriage assembly and may be moved, for example, using ways which may be actuated for example, by heavy duty, servo-driven ball screws. Each way may include a precision absolute encoder on each axis of movement, namely, the horizontal and vertical direction for position feedback. Each carriage <NUM> carries a complete cutter <NUM> and a wheel profile measurement system <NUM>. Each precision cutter <NUM> may be driven by a gear motor <NUM> connected thereto by a belt, shafts or a direct drive.

As shown in <FIG>, rollers <NUM> may have V shaped grooves and be semi-floating axially to account for variation in the dimension of a wheel set <NUM> and changes in the shape of the wheel flange as the surface is cut. The drive rollers may be powered by, for example, servo gear motors (not shown) enabling high responsiveness, precise feed rate control, and monitoring of cutting loads. Such servo gear motors may allow the wheel set to be rotated at a higher speed during the profile measuring steps (described herein) to reduce cycle time while still providing accurate control of the low rotation speeds required for the cutting process. The space between a set of rollers <NUM> supporting one wheel <NUM> may be adjustable to allow for the cutting of a full range of different wheel diameters.

Referring to <FIG> and <FIG>, the system includes an integrated automatic wheel profile measurement system or device <NUM> at each wheel, which is mounted onto the carriage assembly <NUM>. Each wheel profile measurement device <NUM> measures wheel location, diameter, width, and profile as well as wheel set back-to-back, back face runout, and radial runout of the wheel tread. When a worn wheel <NUM> is probed using the wheel profile measurement device <NUM> such information is used to automatically determine the center of rotation of the wheel <NUM> and the desired target diameter or distance to cut the wheel profile and automatically position the cutters <NUM> axially for a particular wheel set. Each wheel profile measurement device <NUM> may be used, if desired, to complete a post-process wheel set inspection and measurement where, for example, final diameters, profile conformity, etc. can be verified and sent to the control system or other data management system.

Once the wheel profile measurement device <NUM> has been used to determine the initial position of the wheel set, the tracking devices <NUM> are then used to follow movement of the wheel set during the cutting or milling process. As shown in <FIG>, the tracking devices <NUM> include following arms <NUM> and adapters <NUM>, one near each wheel. Alternatively, for example, if the system is configured to reprofile a wheel set still affixed to a bogie <NUM> (as described herein and shown in <FIG>), the following arms <NUM> and adapters <NUM> of the tracking device <NUM> may contact a target area on the wheel axle (or bogie <NUM> that is directly coupled to the wheel set i.e., on the wheel set side of any bogie suspension). And, each following arm <NUM> may be manually or automatically positioned under that target area. Each tracking device <NUM> and following arm <NUM> may also be equipped, for example, with a pneumatic cylinder which extends the device and/or arm <NUM> until the adapter contacts the target area and holds it against same throughout the cutting cycle. In the case of a wheel set not coupled to a bogie as shown in <FIG>, the following arm <NUM> may be attached to the hold down mechanisms <NUM>. The following arms may be fitted with precision encoders <NUM> which are used to monitor movement of the wheel set and enable the control system to adjust the radius at which the cutters <NUM> are engaging the wheel <NUM>. The tracking devices <NUM> may be allowed to move in three dimensions, i.e., along an X, Y and Z axis. The end of the following arm <NUM> opposite the probe may be connected to a block which slides along the X and Z axis, i.e., in the front to back and side to side direction. And, the arms <NUM> are free to move in the up and down direction. Precision encoders within the tracking device can then determine movement of the wheel and its center of rotation in three dimensions. And, the device <NUM> can send signals representing the probe positions or changes thereof, which correspond to changes in position of the center of rotation of the wheel, to the control system which can control movement of the cutter <NUM> position. Also, a universal joint may be used between the top end of the arm <NUM> and the adapter <NUM>. This may allow encoded angular motion to be measured in the vertical, horizontal and front to back planes via the universal joint.

Referring to <FIG> and <FIG>, the overhead bridge <NUM> supports a pair of wheel hold down mechanisms <NUM>. The wheel hold down mechanisms <NUM> may include a pair of arms or posts which extend from the station <NUM> and contact, for example, the outer portion of the wheel <NUM> and wheel set <NUM>. The arms each include a contact pad <NUM> which contacts the axle or cartridge roller bearing housing <NUM>. The pad and/or arm is allowed to move vertically to compensate for movement in the center of rotation of the wheel or wheel set. For example, the arm may be extendable and/or include a hinge which allows the contact pad to move while still contacting the wheel set. The area and/or hinge may be biased to apply a force downwardly on the wheel set to assist in maintaining the wheels and wheel set on the rollers. The force should be sufficient to allow the center of rotation of the wheel set to move while maintaining the wheel set on the rollers. In the embodiment shown in <FIG>, the tracking devices <NUM> contact the axle or cartridge roller bearing housing <NUM> to track its movement and the corresponding movement in the center of rotation of each wheel <NUM>. However, other techniques for holding the wheel set <NUM> on the rollers while allowing the center of rotation to move and without chocking the wheel set <NUM> may be used.

An alternative embodiments of wheel hold down mechanisms <NUM> may include a pair of arms which extend from the station <NUM> towards and receive the outer end of the axle and wheel set. The arms may be moveable in multiple dimensions and rotatable relative to the station. The arms may each include curved contact pads which receives the top portion of outer wheel hub. The contact pads are preferably curved in shape and sized to fit the top portion outer portion of the wheel set. The curved contact pads are also allowed to move horizontally to compensate for movement in the center of rotation of the wheel or wheel set. For example, the contact pads may include a rail which moves horizontally within a slot of the arm. In addition, the arms are moveable vertically to adjust to any vertical movement of the wheel. In this embodiment, the tracking device <NUM> may contact the bottom of the wheel hubs <NUM> to track and measure its vertical and horizontal movement and the corresponding movement in the center of rotation of each wheel <NUM>.

Referring to <FIG> the details of a carriage assembly <NUM> are shown. The carriage assembly moves the cutter <NUM> and wheel measurement or probing device <NUM>. The carriage assembly includes a moveable carriage <NUM>, moveable in the vertical and horizontal (y and z) directions. The carriage <NUM> supports the cutter <NUM> used in accordance with the system described herein and wheel probing device or device <NUM>. The carriage assembly <NUM> is moveable in the vertical and horizontal directions so as to move the cutter <NUM> towards the wheel <NUM> and wheel set <NUM> so that the cutter may contact the outer circumference and profile of the wheel <NUM>. A motor <NUM> is used to drive the cutter <NUM> and rotate the same to allow the cutting process to occur. The carriage <NUM> and cutter <NUM> are controlled by the control system which may be activated and monitored by an operator. Coupled to the carriage <NUM> is the wheel profile measurement device <NUM> which is shown in more detail in <FIG>. This device may include, for example, a precision roller <NUM> with a rotary encoder therein. A raised flange on the precision roller <NUM> may trace and contact the rotating wheel <NUM> on the wheel set <NUM>. The wheel measurement device <NUM> is capable of measuring the entire wheel profile in the full axial direction, the thickness of the wheel and its entire circumference. Accordingly, the entire circumference of the wheel <NUM> in a wheel set <NUM> may be measured using the precision roller <NUM> along its entire circumference so as to calculate a full profile shape of the outer profile of the wheel <NUM>. The control system <NUM> is coupled to the precision roller and rotary encoder as well as the carriage assembly <NUM> to measure the exact position and movement of the same. The control system controls one or more mechanisms and the carriage <NUM> to move the wheel measurement device <NUM> vertically and horizontally towards the wheel and wheel set.

A horizontal contact member or probe <NUM> may include, for example, ruby tips or small precision rollers on the inboard and outboard extents thereof such as to contact the inner and outer faces of the wheels <NUM>. The position of the horizontal member or probe <NUM> is monitored by the control system using a precision length gauge such as the Keyance GT2-H32 available from Keyance Corporation of America. Such information combined with the vertical and horizontal position of the carriage assembly <NUM> and may be used by the control system <NUM> to locate and measure the wheel width and rim thickness. A linear guide <NUM> which may be pneumatically or hydraulically operated, may actuate in the vertical direction, and provides position feedback using a linear encoder or magnetostrictive transducer to measure the vertical position of the precision roller <NUM> and the horizontal member or probe <NUM>. The linear guide <NUM> may also be coupled to the control system <NUM> to combine with the information derived from the precision roller <NUM> and horizontal member or probe <NUM> to provide precise measurements regarding the outer profile of the wheel <NUM> from its inner face to its outer face, along with the wheel thickness.

When a wheel set <NUM> is placed upon the system <NUM>, the operator may commence an operation cycle for the same. The control system <NUM> may then extend the wheel profile measurement device <NUM> upward and towards wheel to facilitate taking various measurements. Initially, the center line of rotation of the axis of the wheel set may be calculated based on the position of the horizontal member or probe <NUM> and/or precision roller <NUM> contacting the bottom of the wheel and adding a half of the average diameter of the wheel as determined by measurement obtained from the information derived by the precision roller <NUM> and its rotary encoder.

Referring now to <FIG> and <FIG>, an alternative system <NUM> for reprofiling a wheel set of a railway vehicle may be used to reprofile a wheel set which is located on a bogie or truck <NUM>. The system of <FIG> and <FIG>, operates and is similar to the system described with respect to <FIG>. As shown in <FIG>, the system <NUM> includes a station <NUM> which is capable of supporting a bogie or truck with the railway wheels and wheel sets thereon. The rollers <NUM> and cutters <NUM> operate in the same manner as described previously herein with respect to <FIG>. However, the tracking device <NUM> following arms <NUM> may contact the bogie <NUM> rather than the wheel set <NUM>. In addition, the hold down system <NUM> is configured to contact the bogie <NUM> rather than the wheels.

When the system is used to reprofile wheel set within bogies, different types of an inboard hold down system may be used. For example, a hydraulically actuated system may pull down on the underside of the bogie frame after the operator has positioned an appropriate hook or adaptor. Also, some bogies and loose wheel sets may require hold downs positioned outside of the wheels in order to apply the hold down force to axle boxes, bearings, or other bogie features. A separate hydraulically actuated outboard hold down system may be used in such situations. Also, a support frame may be used to support the end of the bogie opposite of the wheel set being cut. The frame can either support the wheel set that is not being cut or it can be fitted with jacks to support the bogie frame if necessary to accommodate coupled wheel sets. When one wheel set cutting is complete, the bogie may be lifted off using an overhead crane, rotated and set back on the machine to complete the second wheel set. An on-demand hydraulic unit may be included to power the hold down system(s).

The control system <NUM> may include, for example, by a standard industrial PLC with basic motion control modules ensuring ease of use and ease of maintenance. A full-featured, PC-based user interface <NUM> (<FIG>) gives the operator access to an appropriate set of simple screens for reviewing measured wheel set data, selecting processes to be completed, monitoring status, and operating the machine. Additional functionality (and password protectable screens) are provided for maintenance, data management, calibration, etc. Meaningful messages regarding status, interlock conditions, and faults are displayed to facilitate ease of use and efficient troubleshooting. Remote diagnostics connectivity and services are available subject to the customer's IT policies, service provider options, and desired level of support. A dedicated Ethernet port or other communication interfaces or techniques may be used for connection to the customer's network for storage of wheel set data in the customer's vehicle maintenance database.

Referring now to <FIG>, a schematic representation of certain components of the system <NUM> and their communication paths are shown. The control system <NUM> is operatively connected to each cutting tool <NUM> and carriage assembly <NUM> and their associated mechanisms to operate and move each cutting tool <NUM> to commence cutting of each wheel <NUM>. The control system <NUM> is also operatively connected to each of the drive rollers <NUM> to control the operation of the drive rollers and rotate each wheel <NUM> of each wheel set <NUM>. The control system <NUM> is also operatively connected to each tracking device <NUM> which tracks the position of the center of rotation of each wheel and wheel set <NUM>. The control system <NUM> is also operatively connected to each profile measurement system or device <NUM> which measures the profile of a wheel before and/or after reprofiling. The control system <NUM> may calculate the center of rotation of each wheel <NUM> based upon the information obtained by each profile measurement system. Each system <NUM> include multiple cutters, each cutter corresponding to the cutting of a particular wheel of a wheel set. In addition, each system <NUM> may cut multiple wheel sets, if desired. A single control system <NUM> or multiple control systems may be used to determine the position of each cutter operated by the control system. In addition, multiple systems <NUM> may be controlled by a single control system.

Referring to <FIG>, the system performs a process with respect to each wheel <NUM> which is cut by a particular cutter <NUM>. For each wheel, the system using one or more wheel profile measurement systems <NUM> corresponding to one or more wheels <NUM>, will measure each wheel profile. The control system may then calculate the desired center of rotation of each wheel. After the center of rotation is calculated, the control system may then calculate the constant position or distance between the center of rotation of each wheel and a cutter so as to obtain the desired wheel profile after cutting. The control system may activate each drive roller and cutter associated with a particular wheel so as to rotate each wheel and contact the associated cutter with the wheel to create a new profile thereon. For each wheel being cut, the tracking device tracks the movement of the center of rotation of the wheel and the control system calculates the change of position or change in distance of the center of rotation of each wheel. The control system may then adjust the position of each cutter relative to the change of position of the center of rotation for the wheel that the cutter is milling. The process may continue for complete revolution of a wheel relative to a cutter. In addition, the process may be repeated if necessary over multiple revolutions for the same wheel.

The complete operating sequence for reprofiling a wheel <NUM> and wheel set <NUM> may be performed as follows. Initially a wheel set <NUM> (or bogie if attached to a wheel set) is placed directly onto the rollers <NUM> using, for example, an overhead crane. An axial guide system may then be used to, for example, to contact the bogie or individual wheel set as appropriate. Next, the operator may activate the hold down mechanisms <NUM> as necessary to apply a downward force. The control system maintains the hold down force for the balance of the processing of a wheel set. Next, wheel set following arms may be activated to contact either the bogie frame, hold down mechanism or wheel set. The operator may slide the tracking device following arms such that the actual contact point of the arm is lined up under the pre-defined area on the given bogie, hold down mechanism or the control system extends the following arms against the bogie, hold down mechanism or wheel set and automatically maintains contact and monitors movement of the wheel or wheel set throughout the balance of the cycle. A target, such as adhesive backed reflective tape may be applied to rim of one wheel to indicate position of a full wheel rotation. The operator may then confirm that the correct operations have been selected and wheel set type has been entered and then initiates the automatic processing cycle at the control station. The wheel probing device <NUM> measures wheel diameters, widths, locations, and wheel profile. The control system calculates the target or desired wheel diameters required to reprofile the wheel, the number of passes, and the depths of cut. The control system may also check against rim thickness condemning limits and verify that back-to-back wheel dimensions are acceptable. The control system then align cutters <NUM> to wheels along the Z-axis and controlling the system to perform one or more rough cutting passes on the wheels. The wheel probing devices may then measure wheel diameters prior to doing finish cut. Based upon such measurements, the cutter may make one finish cutting pass. The cutter may complete outside radius (if the cutter not configured with integral chamfer). If desired, the system may run a post-machining measurement cycle using the wheel probing devices, and the system may store and/or transfer of wheel set data. The operator may then remove the reflective target, releases and homes the following arms, hold downs, and axial guides. The wheel set and/or bogie may then be removed.

Referring to <FIG>, a further embodiment of a system for reprofiling worn railway vehicle wheels and wheel sets where a railway vehicle (not shown) may be driven onto a set of rails located over a station. This embodiment operates similar to the embodiments described above, but measures and cuts a wheel set while still assembled to a rail vehicle. The station <NUM> may be installed in a pit <NUM> which allows a rail vehicle to be driven or pulled directly over the system via rails <NUM>. These rails should be designed to carry in excess of <NUM> ton (<NUM> kN) axle loads for rail cars and <NUM> ton axle loads for heavy locomotives. Once the vehicle is positioned over the station <NUM>, the drive rollers may lift the wheel set up and a section of rail automatically retracts giving the cutter <NUM> access to the bottom of the wheel <NUM>. In this embodiment, the hold down systems <NUM> include a pair of arms. The arms are pivotably mounted onto posts <NUM>, which are vertically moveable. The hold down systems <NUM> include pads which contact the bogie (not shown) or wheel set (not shown). The pads are thus moveable by rotating the arms and translating the posts.

For the system shown in <FIG>, the complete operating sequence may be as follows. When the system is initialized and the rails <NUM> are in place, the railway vehicle may be transported via the rails <NUM> to the system. A signaling system such as a green light may be used to inform the user that the system is ready for receipt of the railway vehicle. The vehicle can then be driven, shunted or winched via the rails <NUM> onto the rollers <NUM> of the system. The operator may then extend the axial guide system to contact the bogie or the rollers to contact the individual wheel set as needed. The operator may then initiate the hold down systems <NUM> to align with the bogie and initiate the hold down system <NUM> to apply the downward force onto the bogie. The control system <NUM> controls all operations and maintains the hold down force for the entire cutting cycle. Next, the user may actuate the wheel set tracking devices so that the following arms contact the bogie frame (or the wheel sets, if desired). The wheel set following arms contact the target area on the bogie frame, or an adapter may be used to facilitate such contact. The operator may apply a target indicator such as an adhesive backed reflective tape to the rim of a wheel to indicate visually when a full revolution of the wheel has occurred on the system during the cutting process. The operator may confirm the type including the size of wheel and wheel set onto the system and initiate the automatic cutting cycle at the control station. Once the automatic cutting cycle has been initiated, the rollers elevate and lift the wheel set off the rails. The rails may be slideable to automatically retract away from the rollers. The wheel measuring devices may then be actuated to measure the wheel diameters, widths, locations and the wheel profile. In this step, the desired target wheel diameter is calculated by the control system based upon such measurements to and the number of cut revolutions, depths of cut are calculated. In addition, the wheel rim thicknesses and limits including verification of back-to-back dimensions are performed. Next, the cutters align to the wheels along the horizontal and/or vertical axis and one or more rough cutting passes or revolutions are performed as determined by the control system. After a cutting cycle, the wheel diameters may be measured using the wheel measurement devices. If the control system determines that the measured wheel diameter is sufficient or close to the desired size and configuration, the system may perform one or more finished cutting rotations. The complete outside radius of the wheels may be additionally milled if the cutter is not configured with an integral chamfer. At the end of the cutting processes, a post-cutting measurement step may be performed using the wheel profile measurement systems and the wheel measurements and other data may be stored or transmitted by the control system. The operator may then remove the reflective tape or other target indicia and release the following arms, hold down and axial guides. The vehicle may be advanced to the next wheel set thereon and the entire process repeated for an additional wheel set on the vehicle.

Wheel set milling cutter heads, or other milling cutters which duplicate the wheel shape desired in part or whole, may be used as cutters <NUM>. For example, a Stanray TN-<NUM> cutter available from Simmons Machine Tool Corporation of Albany, New York may be used with the system described herein However, other suitable cutters may be also be used. Each precision cutter <NUM> may be driven by a direct-drive <NUM> hp gear motor attached via a spindle or shaft. The spindle may be supported by multiple heavy precision bearings mounted, for example, in a cast iron housing. Each cutter <NUM> may include a machined body with a number of removable bars. Each of these bars is designed to hold a number of indexable, replaceable carbide cutting inserts arranged in such a way as to form a continuous cutting helix which yields the desired tread profile. These insets can be easily indexed without removing the cutter from the machine. The cutters can easily be removed from the machine to swap cutters or index inserts. The cutters are also designed with a set of cutting inserts on the end of the cutter. This enables the cutting of a chamfer or radius tangent to the outside face of the rim based on the probed wheel width and location.

Claim 1:
A method of reprofiling a wheel set (<NUM>) of a railway vehicle on a station (<NUM>) comprising:
disposing the wheel set (<NUM>) on rollers (<NUM>);
determining a center of rotation (<NUM>) of a wheel (<NUM>) on the wheel set (<NUM>);
determining a desired constant distance (<NUM>) between a cutting tool (<NUM>) and the center of rotation (<NUM>) of the wheel (<NUM>); and
rotating the wheel (<NUM>); the method characterized in that
when the cutting tool (<NUM>) is used to mill a profile on the wheel (<NUM>),
(i) the center of rotation (<NUM>) of the wheel (<NUM>) is allowed to move relative to the rollers (<NUM>) while the rollers (<NUM>) are maintained in a fixed location on the station (<NUM>), (ii) radial horizontal and vertical changes in position of the center of rotation (<NUM>) of the wheel (<NUM>) are tracked while the wheel (<NUM>) is being rotated and after the cutting tool (<NUM>) has been activated, and (iii) the cutting tool (<NUM>) is moved to facilitate its location at the desired constant distance (<NUM>) between the cutting tool (<NUM>) and the center of rotation (<NUM>) of the wheel (<NUM>).