PIVOT AXLE ASSEMBLY FOR ROADWORTHY RAILROAD BALLAST TAMPER APPARATUS

Abstract

A rail tamper apparatus is provided, including a chassis configured for being hitched to a semi-tractor trailer for road travel, and also configured for travel on rails of a railroad track, at least one ballast tamping unit mounted to the chassis, a turntable unit mounted to the chassis, and a pivoting axle assembly mounted to the chassis that is retractable relative to the chassis in a road travel position for highway travel, and is extendable from the chassis into a track travel position for operation on the rails, and including a rail wheel drive motor being extendable with the axle assembly.

Description

BACKGROUND

The present disclosure relates generally to a ballast tamper machine for manipulating track ballast under railroad ties and correcting alignment of railroad tracks. More particularly, the present disclosure relates to a railroad right of way maintenance system providing a ballast tamping machine being transportable on a highway and easily convertible between road travel and rail travel and including a retractable pivoting rail wheel axle assembly.

Due to natural factors, such as floods, hurricanes, tornados, or seasonal ground shifting, as well as regular rail maintenance schedules, it is often necessary to correct the vertical and/or horizontal alignment of railroad tracks by manipulating the track ballast supporting railroad ties using a method known as tamping. Conventional tamping machines include vibrating elongate, rigid tamping arms, also referred to as tamping tools. The tamping tools are forced into the ballast on each side of the railroad tie, and vibrate at a given frequency within the ballast. Such vibration, in addition to movement of the tamper tool work head, causes movement of the ballast to support the ties, and the corresponding track at a designated alignment, thereby leveling the railroad tracks.

However, conventional tamper machines are very heavy, long, and overly bulky for highway transportation. Further, even if the tamper machine can be transportable using, for example, a large trailer, special oversize permits and requirements are required by the U.S. Department of Transportation for carrying the tamper machine on a highway. Moreover, once the machine reaches its destination, a heavy-duty lifting machine such as a crane, is needed to move the tramper onto the railway track for operation. Accordingly, the transportation of conventional tamper machines is inconvenient and cumbersome, and incurs high shipping costs due to the difficulties in transporting.

SUMMARY

A roadworthy tamper apparatus or machine is provided, which features a chassis having at least one tamper workhead, at least one turntable unit, at least one reference projector buggy, and at least one set of retractable rail wheels, all mounted to the chassis that is towable as a trailer by a standard semi tractor truck. The present chassis is constructed and arranged so that it meets standard Department of Transportation height and weight regulations for towed semi-type trailers, and does not require special Oversize or Overweight permits.

Included on the present tamper apparatus chassis is a retractable powered rail wheel assembly that features an independently pivoting rail axle assembly pivoting about an axis extending parallel to the longitudinal axis of the respective railroad track. An axle subframe or housing included in the rail axle assembly is selectively retractable vertically relative to the main tamper machine chassis. The pivoting action occurs about a pivot shaft that is mounted to the subframe with spherical bearings for accommodating irregularities in the terrain. At least one spring-loaded latch holds the subframe in position relative to the chassis once the rail wheels are extended to the operational position, in which the rail wheels are in contact with the track. The subframe is provided with its own power source for moving the tamper unit along the railroad track. When the tamping operation is completed and the tamper apparatus is converted for highway travel, the subframe is extended past the operational position, the at least one latch is retracted, and the subframe is retracted to a travel position using a main cylinder.

Further, due to the tamper apparatus's reduced width, length, and weight, and the turntable unit, no special crane is necessary for placing the tamper apparatus on the track for operation. A semi-truck tractor conveniently hauls the tamper apparatus and delivers it to a destination, such as a railroad crossing. In use, the tamper apparatus is lowered and released on the railroad track so that wheels of the turntable unit are engaged on the rails. At this point, the remainder of the tamper apparatus is held suspended above the track and is located along an axis transverse to the rails. A user manually rotates the tamper apparatus supported by the turntable assembly for subsequent operation along the rails.

Prior to lowering the tamper apparatus into engagement with the rails, the present retractable powered rail wheel assembly is lowered relative to the main tamper apparatus frame, to an operational position. Specialized latches are triggered once the assembly is in the lowered, operational position, to prevent retraction of the assembly relative to the tamper apparatus frame.

Accordingly, transitioning of the present apparatus from traveling on the road to traveling and working on the railroad track is easily accomplished, and is performed without resorting to additional heavy equipment or special governmental authorization. Upon completion of the tamping operation, once the tamper apparatus is readied for highway transport, after lifting the tamper apparatus frame from the rails, the present powered rail wheel assembly is slightly lowered or extended further relative to the main frame by designated hydraulic cylinders. This action moves the axle frame below the reach of the latches, which are then retracted. In this manner, the latches are released, permitting the retraction of the powered wheel assembly relative to the main tamper frame, for highway travel.

In operation, the chassis is transitioned from highway movement to a work mode using the turntable as described above. Once the chassis is aligned with the track, the tamper apparatus moves along the track, collecting track alignment data. Once a section of track is discovered that requires alignment, the apparatus moves back over the misaligned rail, and a process known as indexing is begun, where the ballast supporting each misaligned tie is subject to tamping. Once the chassis is in position, the chassis brakes are set, and the biasing clamps press rail wheels of the turntable against an inner surface of a reference rail on one side of the machine On the opposite side, the respective biasing clamp is pressurized to exert pressure against the corresponding inner surface of the rail. Hydraulically controlled hook members are manipulated to grasp and lift the corresponding rail requiring alignment to a desired position. Next, the tamper unit is energized for moving ballast to support the respective tie so that the rail maintains the desired position held by the hook member.

A tamper machine pivoting rail wheel assembly is provided with a rail wheel assembly that is pivotable relative to a chassis about a shaft extending generally parallel to the rails.

A pivoting rail wheel assembly is provided for a tamper machine including powered pivoting latches for retaining the wheel assembly in an extended, rail travel position.

A pivoting, extendable rail wheel assembly is provided for a tamper machine, having latches for holding the assembly relative to a chassis in an operational position, and such that extension of the assembly past an operational position allows disengagement of the latches for retraction to a highway travel position.

More specifically, a rail tamper apparatus is provided, including a chassis configured for being hitched to a semi-tractor trailer for road travel, and also configured for travel on rails of a railroad track, at least one ballast tamping unit mounted to the chassis, a turntable unit mounted to the chassis, and a pivoting axle assembly mounted to the chassis that is retractable relative to the chassis in a road travel position for highway travel, and is extendable from the chassis into a track travel position for operation on the rails, and including a rail wheel drive motor being extendable with the axle assembly.

In another embodiment, a pivoting rail wheel assembly is provided for use with a railway maintenance vehicle having a chassis. The assembly includes a housing configured for being vertically reciprocable relative to the chassis, a pair of rail wheels mounted to the housing, a drive motor associated with the housing and configured for powering at least one of the rail wheels, a pivot shaft associated with the housing and slidably connecting the housing to the chassis, the housing being pivotable about the shaft, and at least one powered latch connected to the chassis and constructed and arranged for maintaining the assembly in a track travel position relative to the chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the present tamper apparatus shown in a rail travel mode;

FIG. 2 is a fragmentary side view of the tamper apparatus of FIG. 1 connected to a semi-truck in a travel mode;

FIG. 3 is an enlarged fragmentary side elevation of the present pivoting axle subframe shown in a travel mode as seen in FIG. 2;

FIG. 4 is a fragmentary side elevation of the subframe of FIG. 3 shown in the operational or work mode for movement along the track when tamping is performed;

FIG. 5 is a fragmentary side elevation of the subframe of FIG. 3 shown partially extended from the chassis past an operational position;

FIG. 6 is a fragmentary side elevation of the subframe of FIG. 3 shown as the subframe is about to be retracted, such that the main cylinder has extended the subframe past the work mode position and the latches are released, permitting retraction;

FIG. 7 is a front elevation of the present subframe taken along the line 7-7 of FIG. 1 and in the direction indicated generally and in the retracted position; and

FIG. 8 is a front elevation of the subframe of FIG. 7 shown in the work mode position.

DETAILED DESCRIPTION

Referring now to FIGS. 1 and 2, a tamper apparatus or machine, generally designated 10, is shown on a portion of a semi-truck, generally designated 12. As is well known in the art, the tamper apparatus 10 is designed to be self-propelled or towed as a separate unit alone or as part of a railway maintenance gang along a railroad track. One aspect of the present tamper apparatus 10 is that the tamper apparatus can be conveniently and directly towed by the semi-truck tractor 12 through the connection with a hitch assembly 14 along the highway on road wheels 15 to a destination site without requiring shipment on the railroad track or on an oversize highway trailer.

For maintenance activities on the track, the tamper apparatus 10 is self-propelled and powered by an engine 16, a battery 18, and a fuel tank 20. As is known in the art, the engine 16 is mainly used for powering a hydraulic system, generally including at least one pump, several hydraulic motors and several hydraulic cylinders. It is preferred that a self-contained electrical power source, such as the battery 18, is installed on the tamper apparatus 10, but it is also contemplated that the power source can be obtained from another unit of the railway maintenance gang. Thus, the engine 16 indirectly provides power to at least one of a pair of front-axle wheels 22 and a pair of rear-axle wheels 24, both sets of which being railway wheels for operation along the track, allowing the tamper apparatus 10 to propel itself to the work-sites on the railroad track. Preferably, the front-axle wheels 22 are equipped with a floating axle frame 26, and the rear-axle wheels 24 are fixedly attached to an axle frame 28. However, it is contemplated that the fixed/floating conditions of the wheels 22, 24 are reversed, depending on the application. While a two-axle tamper apparatus 10 is shown, any number of axle(s) is also contemplated depending on the payload. A separate brake system 30 is installed on the rear-axle wheels 24 to prevent the tamper apparatus 10 from unwanted movement.

A pump (not shown), preferably hydraulic, is driven by the engine 16 to provide power for various tools associated with the tamper apparatus 10. A hydraulic reservoir or tank 32 provides the fluid transmitted by the pump. For example, a ballast tamping unit 34, and a projector buggy 36 are attached to a chassis or main frame 38 of the tamper apparatus 10. It is contemplated that the engine 16, the battery 18, and the fuel tank 20 are also attached to the chassis 38 at desired locations. During railroad track maintenance, under the direction of an operator in a cab 40 mounted to the chassis 38, preferably in closer proximity to the rear wheels 24 than to the front wheels 22, the ballast tamping unit 34 performs packing of the ballast 42 under railroad ties 44 for longitudinally and transversely correcting the alignment of a pair of rails 46 of the railroad track (best seen in FIG. 2). During the transportation of the tamper apparatus 10 on the highway, the projector buggy 36 is stored on the chassis in a retracted position as described in co-pending, commonly assigned U.S. patent application Ser. No. ______ entitled RAILWAY REFERENCE MACHINE HAVING A COLLAPSIBLE PROJECTOR (Docket no. 1425.114260) incorporated by reference. Once the tamping operation begins, the buggy lift assembly 36 is extended for providing a beam projection point for aligning the rail as is well known in the art.

A turntable unit 48, is rotatably attached at substantially a center of mass ‘CM’ of the tamper apparatus 10, for enabling manual horizontal rotation of the tamper apparatus 360 degrees relative to a plane defined by the chassis 38. Another aspect of the present tamper apparatus 10 is that orienting and positioning of the apparatus is easily achieved by manually rotating the turntable unit 48 when the apparatus is lowered on the rails 40. The turntable unit 48 is described in greater detail in co-pending, commonly assigned U.S. patent application Ser. No. ______ entitled ROADWORTHY RAILROAD BALLAST TAMPER APPARATUS (Docket no. 1425.114261), which is incorporated by reference. A feature of the present tamper machine 10 is that the projector buggy 36, the tamper unit 34, the operator cab 40 and the turntable unit 48 unit are all mounted to the chassis 38 such that the machine 10 is directly towable on the road by the semi truck tractor 12 without requiring a trailer or special use/oversize permits. The machine 10 has a width of less than or equal to 96 inches, a length of less than or equal to 104 feet and a weight of less than 80,000 pounds.

Referring now to FIGS. 3-6, the present retractable powered rail wheel assembly or pivoting axle assembly is generally designated 50, and includes a housing 52 which reciprocates vertically relative to the chassis 38 under the power of a pair of lift cylinders 54, connected at one end to the chassis 38 and at another to the housing 52. The rail wheel assembly reciprocates between a road travel position (FIG. 3) and an extended or track travel position (FIG. 4). Included in the frame chassis 38 is a pair of vertical slots or tracks 56 which guide the movement of the housing 52, through engagement of ends 58 of a main pivot shaft 60. The shaft 60 slidably connects the housing 52 to the chassis. More specifically, the shaft ends 58 are supported in spherical bearings 62 which are enclosed in guide bosses 64 that are slidably engaged in the slot 56. The shaft 60 is held in place in the slots 56 by endcaps 66 which also enclose the spherical bearings 62. Due to the weight of the tamper machine 10, the spherical bearings 62 permit flexing of the shaft 60 due to the load of the machine.

Thus, it will be seen that the housing 52 pivots about an axis defined by the shaft 60 which extends parallel to the rails 46. This pivoting action facilitates the movement of the tamper assembly 10 on the rails 46, especially about curves.

Included on the housing 52 is an axle drive motor 68, preferably a hydraulic motor powered by the pump 32 on the tamper machine 10. The motor 68 moves with the housing 52, and powers the front axle wheels 22, which are mounted to the housing, using a transmission linkage of the type well known in the rail maintenance art. Thus, when traveling upon the rails 46, motive power for the tamper machine 10 is provided by the motor 68 driving the wheels 22. Also mounted on the housing 52 is a brake assembly 70 under control of the operator in the cab 40 for selectively exerting braking force on the wheels 22 through brake pads 72.

An important feature of the wheel assembly 50 is that the housing 52 is held in a locked extended position relative to the chassis 38 during operation of the tamper machine 10 on the rail 46 by at least one and preferably a pair of latches, generally designated 74. The latches 74 each engage a corresponding endcap 66 and also extend partially into the slot 56 for holding the housing 52 in the extended position relative to the chassis 38.

Referring now to FIGS. 3-6, each latch 74 includes a pivoting latch arm 76 pivotably mounted to a pivot boss 78 on the chassis 38 that extends transversely to the longitudinal axis of the rails 46. A dogleg end 80 of the latch arm 76 is connected to one end 82 of a fluid power latch cylinder 84, with an opposite end 86 of the cylinder being pivotally attached to the chassis 38. While the cylinder 84 is shown as a spring return hydraulic cylinder, other fluid power devices are contemplated, including but not limited to dual acting hydraulic cylinders.

Opposite the dogleg end 80, the latch arm 76 has a latch end 88 constructed and arranged for engaging the endcap 66 and also at least partially inserted into the vertical slot 56. As such, the end 88 has a footplate 90 oriented at an angle ∂ to an axis of the latch arm 76 so that when the latch arm is extended, there is a parallel, face-to-face engagement between the footplate and an upper surface of the endcap 66 (FIG. 4). A guide surface 92 (FIG. 6) on the latch arm 76 is angled to be oriented parallel to corresponding surfaces 94 of the chassis 38 adjacent the slot 56. A portion 96 of the latch end 88 actually slidingly engages the slot 56.

During the process of converting the tamper machine 10 from road travel to rail travel, as the lift cylinders 54 lower the housing 52 from the travel position of FIG. 3 towards the rails 46, the guide surface 92 on each latch arm 76 slidingly follows the surface 94. As seen in FIG. 4, once the housing 52 reaches the rail travel position, the cylinders 54 are held in position, and the footplate 90 engages the endcap 66, preventing any upward movement of the housing 52 relative to the chassis. Due to the geometry of the latch arm 76, by pressurizing a piston 97 of the rod end 82 of the piston of the cylinder 84 (shown accomplished by a coil spring 97a, and the mechanical advantage of the chassis 38 over the latch arm, relatively little force is needed to hold the latch arm in position. Also, it will be seen that the portion 96 of the latch arm end 88 is engaged in the vertical slot 56.

Referring now to FIGS. 5 and 6, when it is desired to convert the tamper machine 10 from the extended or track travel position back to the road travel position for highway travel, the latches 74 are released by extending the lift cylinders 54 further past the track travel position, thus distancing the endcaps 66 out of engagement with the footplates 90. Next, the latch cylinders 84 are energized for rotating the latch arms 76 about the pivot bosses 78 as seen in FIG. 6 to a retracted position so that the latch arms do not inhibit retraction of the housing 52 relative to, and closer towards the chassis 38. Once the latch arms 76 are free of engagement with the chassis 38, the lift cylinders 54 retract the housing 52 and the latches 74 back to the road travel position of FIG. 3.

Referring now to FIGS. 7 and 8, another important feature of the wheel assembly 50 is that the lift cylinders 54 are located outboard of the front rail wheels 22. In addition, bearings 98 for the rail wheels 22 are located inboard of the wheels. This mounting arrangement reduces the overall width of the assembly 50 and also of the tamper machine 10, to facilitate the machine's ability to comply with roadworthiness as required by US transportation regulations. A derail bar 100 (FIGS. 3-6) on the housing 52 contacts the rail 46 in the event the wheels 22 become disengaged from the rail. Also seen in FIGS. 7 and 8 is a pulley 102 used in a preferred chain drive transmission used to transmit power from the motor 68 to the wheels 22 through engagement with a corresponding axle pulley 104.

While a particular embodiment of the present pivoting axle assembly for a railroad ballast tamper apparatus has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the present disclosure in its broader aspects.

Claims

1. A rail tamper apparatus, comprising: a chassis configured for being hitched to a semi-tractor trailer for road travel, and also configured for travel on rails of a railroad track;at least one ballast tamping unit mounted to said chassis;a turntable unit mounted to said chassis; anda pivoting axle assembly mounted to said chassis that is retractable relative to said chassis in a road travel position for highway travel, and is extendable from the chassis into a track travel position for operation on the rails, and including a rail wheel drive motor being extendable with said axle assembly.

2. The apparatus of claim 1, wherein said apparatus has a weight of less than 80,000 pounds and a width of less than or equal to 96 inches.

3. The apparatus of claim 1, wherein said pivoting rail wheel assembly is provided with a pivot shaft extending generally parallel to the rails, and said assembly is pivotable relative to said chassis about said shaft.

4. The apparatus of claim 1, wherein said pivoting rail wheel assembly is provided with powered latches connected to said chassis and constructed and arranged for maintaining said assembly in said track travel position relative to said chassis.

5. The apparatus of claim 4, wherein said latches are constructed and arranged for rotatably operating between an extended, rail travel position, and a retracted position.

6. The apparatus of claim 5, wherein said latches include a latch arm having a latch end configured for engaging a slot in said chassis.

7. The apparatus of claim 5, wherein said pivoting rail wheel assembly is provided with a main shaft with endcaps, and said latches are configured for engaging said endcaps in said rail travel position.

8. The apparatus of claim 5, further including at least one lift cylinder connected to said chassis and to said pivoting rail wheel assembly for reciprocally moving said assembly vertically relative to said chassis, said at least one lift cylinders being constructed and arranged such that extension of the assembly by said at least one cylinder past an operational position allows for disengagement of the latches for subsequent retraction of said assembly to a highway travel position.

9. The apparatus of claim 8, further including a pair of said lift cylinders, said lift cylinders being mounted to said rail wheel assembly outboard of a pair of rail wheels mounted to said assembly.

10. The apparatus of claim 9, further including bearings for said rail wheels, said bearings being located inboard of said wheels.

11. A pivoting rail wheel assembly for use with a railway maintenance vehicle having a chassis, said assembly comprising: a housing configured for being vertically reciprocable relative to said chassis;a pair of rail wheels mounted to said housing;a drive motor associated with said housing and configured for powering at least one of said rail wheels;a pivot shaft associated with said housing and slidably connecting said housing to said chassis, said housing being pivotable about said shaft;at least one powered latch connected to said chassis and constructed and arranged for maintaining said assembly in a track travel position relative to said chassis.

12. The assembly of claim 11, wherein said latches are provided with fluid power cylinders and are constructed and arranged for rotatably operating relative to said chassis between an extended, rail travel position, and a retracted position.

13. The apparatus of claim 12, wherein said latches include a latch arm having a latch end configured for engaging a slot in said chassis, and said main shaft is provided with endcaps, said latches are configured for engaging said endcaps in said rail travel position.

14. The assembly of claim 12, wherein said latches are constructed and arranged, so that when in said retracted position, said housing is movable vertically towards said chassis.

15. The assembly of claim 11, further including at least one derail bar disposed on said housing.

16. The assembly of claim 11, further including a brake assembly mounted on said housing for exerting braking force on said rail wheels.