Railway ballast excavator having inclined portion

Abstract

A railway ballast excavating apparatus comprising a guide frame having an endless excavating chain mounted thereon, the guide frame having a first portion for insertion beneath the railway tracks and a second portion parallel and inclined with respect to the first portion, the first portion for excavating ballast and the second portion for elevating the excavated ballast in order to deposit the excavated ballast in a pile adjacent the railway tracks. The apparatus is powered by a rubber-wheeled motive vehicle and can be advantageously lifted from the railway tracks in the event of an oncoming train.

Description

FIELD OF THE INVENTION [0001] The invention relates to the excavation of ballast from beneath railway tracks and the simultaneous elevation and piling of excavated ballast alongside the railway track. More particularly, the invention relates to an apparatus and method of excavating railway ballast for the purpose of repairing small sections of track using a mobile endless-chain type excavator having a horizontal portion for excavating the ballast and an inclined portion for elevating the excavated ballast. BACKGROUND OF THE INVENTION [0002] Railway lines generally comprise a set of spaced apart rails mounted on a plurality of transversely placed railway ties that are located upon a bed of compacted ballast material. The rails, ties and ballast must be routinely replaced and machines for removing, cleaning and replacing ballast, such as described in U.S. Pat. No. 5,090,484, are known in the art. However, these machines are large and not particularly well suited to removing ballast fr...

AI Technical Summary

Benefits of technology

[0013] The apparatus may be powered using a hydraulic motor or motors that may be releasably connected to a source of fluid power on the motive vehicle using suitable fluid conduits. The releasable connection between the articulated arm and the frame and between the source of fluid power and the hydraulic motor(s) permits the motive vehicle to be readily de-coupled from the apparatus. In the event of an oncoming train, it is often desirable to remove the apparatus from the tracks to prevent potential damage to either the train, the apparatus, or the motive vehicle. In the prior art, it has been necessary to move the apparatus along the track until a siding has been reached that permits the apparatus and motive vehicle to be moved off-line. In the present invention, the releasable connections permit the apparatus to be readily lifted from the track using the articulated arm of the motive vehicle and set alongside the tracks. The railway wheels may then be raised, permitting the rubber-wheeled excavator to be moved off of the tracks alongside the apparatus. When the train has passed, the apparatus may be again positioned on the tracks using the excavator and work may be resumed. This saves a tremendous amount of wasted time as compared with prior art ballast excavating machines.

[0015] During ballast excavation, debris may have a tendency to accumulate within the guide frame behind the excavating chain. The apparatus may desirably be equipped with debris clearing holes in the guide frame to permit the debris to naturally fall out of the guide frame and to permit debris to be readily cleared from the guide frame using a high-pressure water spray or jet of compressed air. The accumulation of debris can significantly affect the overall weight and balance of the apparatus and the removal of debris is desirable in facilitating the removal of the apparatus from the railway tracks.

[0017] In the prior art, excavated material quickly accumulates in the vicinity of the outward end of the guide frame, which interferes with the rate of excavation, increases the likelihood for damage to the apparatus, and limits the amount of material that can be removed in each transit of the apparatus along the tracks. To overcome these disadvantages, the present invention is equipped with a first portion and a second portion that is parallel to the first portion but inclined thereto. This second portion serves to elevate the excavated material and deposits the excavated material in a pile alongside the railway track. The angle of inclination in some part depends upon the amount of material desired to be removed in a single transit of the apparatus along the tracks. If the full width of the tracks is to be excavated in a single transit (which normally results in a first portion length in excess of 13 feet), then a greater angle may be required as compared with an excavating unit having a shorter first portion. However, larger inclination angles have the disadvantage of losing more of the excavated material while elevating, causing the pile to be spread out alongside the tracks and generally reducing the efficacy of the second portion. It has surprisingly been found that only a small angle is required for proper pile formation, even during full-width cutting operations. The second portion may be inclined with respect to the first portion at an angle of from 10 to 45 degrees, preferably from 15 to 30 degrees, more preferably from 20 to 23 degrees, yet more preferably about 22 degrees.

[0018] A further benefit of using the smallest allowable inclination angle is found in the excavating chain. Since the excavating chain is required to deflect upwardly as it travels from the first portion to the second portion, the excavating chain may be provided with one or more universal joints between each link. The universal joints may comprise a semi-spherical eye within a complementary bearing race that permits the normally vertical pivot axis between each link to deflect to an angular orientation as the joint passes from the first portion to the second portion. As the inclination angle of the second portion increases, so too does the required deflection of the universal joint. In order to keep the chain as robust as possible, it is therefore desirable to utilize the smallest allowable inclination angle in order to reduce the required deflection of the universal joint. The use of a joining link having two universal joints between each excavating link is desirable in that it allows the deflection angle of each individual universal joint to be further reduced.

[0019] Each excavating link of the excavating chain may comprise an outwardly projecting excavating lug having a row of horizontally and vertically spaced apart excavating teeth. The individual teeth may be angled with respect to one another. The row of teeth may form an inclined row angle relative to the direction of movement of the excavating chain. The row angle may correspond to the inclination angle of the second portion so that when the excavating link is on the second portion, the row is substantially horizontal. This facilitates elevation of excavated material using the second portion, thereby reducing the tendency toward pile spreading and further reducing the allowable inclination angle. The row angle may be from 10 to 45 degrees, preferably from 15 to 30 degrees, more preferably from 20 to 23 degrees, yet more preferably about 22 degrees.

[0020] In the present invention, it is desirable that the second portion is substantially aligned with the first portion. This causes the second portion to eject material transversely of the railway track during operation of the excavating unit. If the second portion were not parallel with the first portion, the excavated material would have a tendency to be ejected from the first portion and not elevated using the second portion. Prior art devices have utilized a curved guide shield to prevent this ejection of material; however, a guide shield simply causes the excavated material to accumulate at the curve, reducing the throughput of the excavating apparatus and increasing the likelihood for excavated material to become lodged, resulting in mechanical failure. By keeping the second portion substantially parallel with the first portion, the need for any guide shield is reduced and desirably eliminated.

Problems solved by technology

However, these machines are large and not particularly well suited to removing ballast from relatively small sections of track or for repairing a portion of a track.

This apparatus is limited in that ballast material can only be excavated from the immediate vicinity of the excavating vehicle and, since these vehicles are quite heavy, this can cause track instability resulting in misalignment and the need for extensive repair.

This spreads the material around in the vicinity of the tracks, making it difficult to collect and remove at a later time.

Although the apparatus is suited for small track repairs, the apparatus cannot be operated continuously along a small section of track, such as a siding.

The excavated material accumulates behind the apparatus; the material must therefore be dislodged as the apparatus is removed, with the disadvantages described above, and driven over by the forklift vehicle as the apparatus is advanced beneath the track.

The apparatus is not suitable to continuous operation along a small section of track.

However, the apparatus suffers in that accumulated material is deposited immediately adjacent the end of the chain excavator and hampers excavation of additional material.

This is operationally cumbersome and requires additional labour and equipment.

Moreover, the apparatus is vehicle mounted and neither the apparatus nor the vehicle can be readily removed from the railway tracks.

This can pose a problem in the event of an oncoming train, even if the train is on an adjacent set of tracks.

This requires periodic emptying of the bulk material loading wagon and is operationally cumbersome as compared with simply depositing the material in a pile.

Also, the excavating chain apparatus is mounted to a railway vehicle and neither the apparatus nor the vehicle can be readily removed from the track in the event of an oncoming train.

However, no such apparatus is currently available and the need currently exists for an improved railway ballast excavating apparatus having some or all of the foregoing features.

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