Pressure-squeeze type tampers are typically used in tie gangs during maintenance, such as when ties of a rail system are being replaced. However, as these tampers use opposed, vibrating tamping bars, new ballast is not placed under the ties. Rather, these devices simply squeeze the existing foul ballast under the ties, often without any real compaction, depending on how fast and how many insertions the operator uses. This may result in new ties often not being in bearing through several surfacing cycles, essentially transferring the load to the remaining, possibly weaker ties, negating much of the benefits of the spot tie renewal and resulting in weak and rough riding track.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Reference will now be made in detail to the description of the disclosure as illustrated in the drawings. While the disclosure will be described in connection with these drawings, there is no intent to limit it to the embodiment or embodiments disclosed herein.
In this regard, various embodiments of a Ballast Replacer-Compactor may remedy one or more of several problems associated with the current use of pressure-squeeze type tampers in tie renewal gangs. In particular, in some embodiments, a Ballast Replacer-Compactor (BRC) may work on a different principle, altogether. A BRC (100) (such as the embodiment depicted in
The BRC has a crib compactor plate mounted behind the target tie; this vibrating plate is deployed and compacts the crib ballast behind the target tie as the compactor bars on the front side are withdrawn. This assures that the cribs are tight and providing the required lateral and longitudinal resistance needed in freshly disturbed track to have adequate stability, especially in hot weather to avoid sun kinks.
As the crib compactor and compactor bars, on opposite sides of the target tie, do not engage the ballast at the same time, the ballast is not trapped between two high-pressure, vibrating, squeezing faces that tend to break and destroy the ballast—as the current pressure-squeeze tampers often do.
In some embodiments, a variable rate of oscillation (OPM) frequency for the compactor bars and the crib compactor may be used, as higher frequencies aid insertion into the ballast but lower frequencies are more effective during the compaction portion of the cycle. The BRC may be fitted with variable-rate oscillation vibrator motors and can change the higher frequency OPM during the stroke to push the crib ballast down through the surrounding ballast and then reduce the OPM's for better compaction. The compactor pressure may be variable and can be set by the operator for optimum compaction of the ballast under the target tie without humping the track.
The result of these innovations is a Ballast Replacer-Compactor that may, in some embodiments, provide the proper consolidation and support under spot-renewed crossties after the first pass, resulting in reliable, more uniform ballast support and higher quality, safer track. This technique can be scaled and speeded up to provide the same valuable benefits to production surfacing/tamping equipment, resulting in longer intervals between surfacing cycles and less geometry degradation and rough track in all tracks, including heavy-tonnage areas of operation.
An example embodiment is depicted in the illustrations of
Reaction mass (1)—two are provided, with each mass weighing approx. 2,000-2,400 lbs. per Replacer/Compactor Work Head. The reaction mass (1) provides the downward reaction force required to push the crib ballast (14) down and compact it without having to anchor to the rails (13) or humping the track. The mass (1) and attached components of Replacer/Compactor Work Head can be raised and lowered and also traversed like a switch tamper to provide full compaction coverage of bearing area (see plan view
Hydraulic cylinder (2)—four are used, one per tamping bar. The hydraulic cylinders provide closing action to compactor bars. Hydraulic cylinder (2) is controlled by sequence and pressure sensors to provide the arcuate (e.g., elliptical) path of compactor bars and proper compaction forces. The range of forces varies by ballast type and condition, and can be field adjusted.
Compaction head frame (3)—two are attached to each mass (1). Frame (3) provides mountings and pivots for working components of the compaction head.
Crib compactor (4)—comprised of four sections, two each in the gage of track and one each on field side of both rails (13). Each section is fitted with a free-body vibrator (5) that compacts the crib ballast (14) after the tie bed ballast has been compacted. Each section is supported and deployed by linkage (6) and lifting cylinders (7). In some embodiments, commercial concrete vibrators may be used to provide oscillation at the correct, variable OPM for the ballast type being worked.
Compactor bars (8)—two per compaction head, with one on the gage side, one on the field side of each rail. Compactor bars (8) are driven by eccentric drives (9) and closure activated by cylinders (2). Compactor bars (8) have replaceable pusher faces (10) that are shaped to clear ties during arc of travel and are easily replaceable for wear. The pusher faces are supplied in different shapes to suit the type of ballast (e.g., large gradation, sharp stone vs. gravel, for instance).
Oscillation eccentric drive (9)—each compactor bar (8) pivots from an eccentric drive, which is driven by a variable-speed hydraulic motor (not shown). In this embodiment, each eccentric drive provides up to ¼″ throw at OPM variable from 1,000 to 3,600 OPM (optimum OPM for pushing and compacting actions are programmed into the control system depending on ballast type).
Pusher faces (10) are in position where replacer/compaction cycle begins when operator lowers Replacer/Compaction work head to “start” Position 3. Tie lock jaws also engage ties at this position.
Shaded area (11) shows “swept” area covered by the pusher faces (10) as they pass through their paths from insertion into the crib. In some embodiments, width is 7″ +/−1″, maximum width that is compatible with efficient ballast moving and compacting. In
Patterned areas (14) in
Crossties (12)—7″×9″, conventional wood ties at 18″ OC shown. Other tie types and configurations may be used. Concrete ties are spaced differently but are handled similarly. It should be noted that an adjustment of the compaction arc may be required to provide clearance for oversized ties.
Chassis (22)—includes flanged wheels (30) fitted to axles, which support a frame fitted with various components, such as an engine, hydraulic and pneumatic pumps and compressor, and an electrical system, and having an operator control station, propulsion system, brakes, etc.
Tie locks (29)—two sets are used, mounted on the field side of rails (13). The tie locks (29) engage ties (12) to prevent sliding induced by asymmetric pressure such as that exerted by the compactor bars on only one side of the ties, and also the crib compactor forces on the ballast in the trailing crib. The ties are clamped by two fixed jaws (15) and two movable jaws (16), activated by two hydraulic cylinders (17). These components are mounted on two welded steel frames (18), which in turn are supported by four pivotally mounted arms (19) actuated vertically by two hydraulic cylinders (20) and are attached to a bracket (21) on the front of the chassis (22).
Shaded area (31) shows the width across the track that the pusher faces (10) and crib compactors (4) and (5) can reach and compact effectively.
Fouled ballast (32) is the ballast section underlying the crossties (12) that is often badly fouled.
Phantom outlines (33) showing mass (1), pusher faces (10), and crib compactor (4) at their innermost position and also shows the width across the track that can be tamped effectively.
The aforementioned components are shown in the deployed condition with the track-engaging tool elements engaging the ballast and ties in the work position in
For convenience and speed during operation, there are three main positions of the track-engaging tool elements: Position 1—as shown in
Operating Sequence
The operator propels the BRC to the worksite and then places the tool elements into Position 2 as noted above. The BRC is then aligned with the first target tie to be tamped and the major tool elements are lowered, including the mass (1) and the tool elements attached (i.e., the compactor bars (8), the tie lock assemblies (29) and the crib compactors (4), as well as the associated sub-elements described above).
The tool elements are automatically sequenced with electro-hydraulic controls to reduce operator effort and speed up operations. The operator chooses at what rate to traverse the compactor bars (8) and the crib compactors (4) to reach good ballast consolidation as this will vary depending on the type ballast and how much it has been disturbed during old tie removal and new tie installation. When the compactor bars (8) have completed each cycle of compaction of the tie bed ballast, the crib compactors (4) are cycled on to compact the crib on the trailing side of the target tie (12).
When the compactor bars (8) and crib compactors (4) have completed the compaction of the tie bed and crib ballast, the track-engaging tools are raised to Position 2 (noted above) and the operator propels the BRC to the next target tie, at which time the compaction sequence is repeated.
This sequence is unique in placing new, clean ballast into the tie bed under the tie and also compacting the crib ballast. Both of these items are vital in getting newly-installed ties to have equal bearing of the wheels loads with the older ties already in track. Faster operation can be achieved by adding additional compactor bars (8) and crib compactors (4), with a larger horsepower engine and hydraulic system as required to match the power needs. The benefits of placing the clean ballast under the ties and consolidating the crib ballast would result in less track settlement and longer surface life.
Component List of an Example Embodiment
It should be emphasized that the above-described embodiments are merely examples of possible implementations. Many variations and modifications may be made to the above-described embodiments without departing from the principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.
This utility patent application claims the benefit of and priority to U.S. Provisional Application 62/165,246, filed on May 22, 2015, the entirety of which is incorporated herein by reference.
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