Patent Application
20170167083
Generally, railroad tracks include a pair of parallel rails coupled to a series of laterally extending ties (or sleepers). Ties may be made from concrete or wood. Each tie is coupled to the rails by metal tie plates and/or spring clips. The ties are disposed on a ballast bed. The ballast may be a hard particulate material, such as gravel. The ballast filled space between the ties is called a crib.
Although appearing rigid, rails are flexible members that can bend and distort, for example under the load of trains passing over. The ballast acts like a cushion absorbing some of the shock. Ballast can also help keep the rail level and allow moisture and rain water to drain away.
During installation and maintenance, ballast may be “tamped” to maintain proper position of the ties. Tamping involves agitating the ballast to allow the particles to re-position, and compact it under the tie.
A tamping device includes one or more workheads mounted on a motorized vehicle that travels on the rails. A workhead may include a pair of elongated, vertically extending tools structured to move together vertically and horizontally in a pincer-like motion. The workhead has two sets of tools spaced so that each tool may be disposed on opposite lateral sides of a rail. The workhead may further include a vibration device configured to rapidly vibrate the tools.
A tamping vehicle typically carries at least one operator. The vehicle accelerates under its own power to the ties requiring work. As it approaches the tie, it slows down, then stops at a tie and performs the required tamping work, and moves to the next tie to repeat the cycle. Tamping work may involve agitating and compacting the ballast through the vertical movement and vibration of the workhead. The constant movement and vibration of the tamping device may cause discomfort to operators sitting in tamping vehicles for extended periods of time.
In an example, a rail maintenance vehicle includes a frame, a workhead, an actuator, a pilot valve, and a throttling valve. The frame includes wheels that travel along rails. The actuator extends and retracts the workhead with respect to the frame. The pilot valve receives a fluid and controls the flow of the fluid to at least one output. The throttling valve adjusts a pressure of the fluid at an output relative to a pressure of the fluid at an input. The pilot valve and the throttle valve are coupled such that the fluid travels through the pilot valve and the throttling valve to cause the workhead to be extended or retracted.
In another example, a method of operating a maintenance vehicle includes: supplying fluid to a pilot valve; supplying the fluid to a throttling valve that adjusts a pressure of the fluid at an output relative to a pressure of the fluid at an input; and controlling an actuator that extends and retracts a workhead relative to a frame of the vehicle using the fluid exiting the throttling valve.
Embodiments of a vertical ride quality system and related methods for reducing the vertical vibration in a rail vehicle are described. It is to be understood, however, that the following explanation is merely exemplary in describing the devices and methods of the present disclosure. Accordingly, any number of reasonable and foreseeable modifications, changes, and/or substitutions are contemplated without departing from the spirit and scope of the present disclosure.
In an embodiment, the vertical ride quality system is employed in a tamping machine rail vehicle, as illustrated in
The tamping device 106 may include multiple workheads. In the side view of
Tamping vehicle 100 may also include a tracking device 112 that measures the general linear movement of the rail vehicle 100 along the rail track 101. Cabin 108 may be structured such that it remains stationary relative to the frame assembly 102 as the rail vehicle 100 moves along the railroad track 101.
Referring to
The output sides 220/224 of the throttling valves 214/216 may be coupled to a spool 232 of the main valve 230. The hydraulic fluid from the throttling valves 214/216 controls the position of the spool 232, which in turn sets the speed and direction of the actuator 240. After passing the spool 232, the hydraulic fluid may be supplied to the main valve 230 or may be directed to the return 238. The main valve 230, based upon the position of the spool 232, directs hydraulic fluid from the source 202 to the actuator 240, which causes the tamping workhead to raise or lower. Hydraulic fluid may return via return 238.
In an example, the throttling valve 214 may be associated with the compression stroke of the actuator 240, which may in turn correspond to raising the tamping workhead. The throttling valve 216 may be associated with the extension stroke of the actuator 240, which may in turn correspond to lowering the tamping workhead.
In an example, the orifice 206 may be enlarged (for example 1 mm as compared to 0.8 mm) to provide a greater range of available pressures at an output side 220/224 of the throttling valves 214/216. Conversely, a smaller orifice (for example 0.8 mm as compared to 1.0 mm) may be used to reduce an upper limit as to how fast the main valve 230 can change direction and stroke of the actuator 240. The size of the orifice controls the speed at which the pilot valve 204 shifts, which in turn (after passing through the throttling valves) controls the speed at which the spool 232 shifts. Controlling the rate at which the spool 232 of the main valve 230 shifts reduces the acceleration of the actuator 240.
In operation, the pilot valve 204 may select whether hydraulic fluid is directed to lift or lower the tamping workhead. The throttling valve 214/216, based upon its setting, affects how quickly the spool in the main valve 230 moves by changing the pressure and/or flow rate of the hydraulic fluid reaching the spool.
The throttling valve 214/216 may reduce the impact induced in the tamping vehicle 100, and by extension the operator, by controlling how quickly the tamping workhead is inserted into and removed from the ballast. In the example where two throttling valves are included, the up stroke and the down stroke may be individually controlled. This allows the advantage of adjusting the stroke that is causing the most induced impact while allowing faster action on the other stroke to improve workhead cycle time. For example, the pressure to the side of the spool associated with raising the workhead may be limited more than the pressure to the side of the spool associated with lowering the workhead. It will be appreciated that multiple throttling valves may be provided for each workhead. For example, if the vehicle includes four workheads, there may be eight throttling vales to independently control the up and down stroke of each workhead individually.
The engine drives a pump that supplies oil (or another hydraulic fluid) to the main control valve 352. In an embodiment, orifice 308 is connected to this pump, and oil is ported so that it goes through the pilot valve 302, throttling valve 304, main control valve 352 and back into the engine spool. Oil delivered through orifice 308 controls the movement and speed of a spool of the main control valve 352 thereby controlling the acceleration of an actuator coupled to the main control valve 352, which in turn controls impacts and vibrations experienced by the vehicle, and thus also the movement of seat assembly 120. By controlling the flow of the oil, valves 302, 304, and 352 collectively dampen the actuator and by extension the vibration of seat assembly 120. Throttling valves 304 and 305 control the speed of the spool that shifts directions of the main control valve 352. Throttling valves 304/305 may be of a gate valve type that include a knob and a faucet. The main control valve 352 controls the vertical movement of a workhead of tamping device 106.
In an embodiment, manifold 360 includes one or more main control valves 352 for each of the one or more workheads of tamping device 106. For example, the manifold 350 may include four main control valves 352 respectively associated with four workheads.
In an embodiment, the engine drives a pump that supplies oil to manifold 360. Orifice 308 is connected to this pump, and oil is ported so that it goes through the pilot valve 302, throttling valve 304/305 (which also may be included as a part of the manifold 360), main control valve 352 and back into the engine spool. The throttling valve 304/305 controls how fast the spool in the main control moves and the amount of oil that respectively flows into that one of the four main valves 352.
In an embodiment, system 300 includes two throttling valves, valves 304 and 305. The pair of throttling valves may be manually and individually adjustable. In an embodiment, a first throttling valve, for example valve 304, may affect the down stroke of one or more workheads, and a second throttling valve, for example, valve 305, may affect the up stroke of one or more workheads. In an embodiment, the twin throttle valves can be adjusted to avoid significantly prolonging the workhead cycle yet still provide dampening of system 300. In this manner, the pair of throttling valves 304 and 305 can be adjusted by an operator to control the shifting time of the pilot valve 302 and the main control valve 352.
It will be appreciated that twin throttling valves are not required. For example, a single throttling valve may be used in place of the twin throttle valves. The throttling valves may also be disposed at different locations in the system. For example, the throttling valve may also be placed before the pilot valve.
It will also be appreciated that this disclosure is not limited to rail vehicles that carry an operator. For example, an autonomous or drone vehicle can also realize advantages of the present disclosure such as reduced mechanical stresses on various parts of the vehicle.
The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. Moreover, the above advantages and features are provided in described embodiments, but shall not limit the application of the claims to processes and structures accomplishing any or all of the above advantages.
Additionally, the section headings herein are provided for consistency with the suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Further, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Brief Summary” to be considered as a characterization of the invention(s) set forth in the claims found herein. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty claimed in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims associated with this disclosure, and the claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of the specification, but should not be constrained by the headings set forth herein.
