Patent Application
20070283837
1. Field of the Invention
The invention relates to rail maintenance equipment and, more particularly, relates to a tie plate inserting machine for inserting a previously positioned tie plate between a rail and a tie. It additionally relates to a method of inserting a previously positioned tie plate between a rail and a tie.
2. Discussion of the Related Art
Tie plates are widely used in railway installations. Specifically, the rails of a railroad track are usually secured to cross ties by spikes driven through tie plates positioned between the rail and the tie. The heads of the spikes overlap the base of the rail, and the tie plates block the rails from lateral movement.
It is often necessary during railway track maintenance and/or construction operations to insert a tie plate beneath the rail. For instance, in a typical tie replacement operation, the spikes are pulled from the tie plates to release the tie from the opposed rails. A machine then pulls the tie out from beneath the rails, knocking the tie plates loose as the tie is withdrawn. A laborer then retrieves the tie plates with a hook and sets them aside. Another machine then inserts a new tie beneath the lifted rails. One or two operators then reinsert the tie plates on the top surface of the tie. The tie plates are then inserted between the tie and the rails, either manually or using a machine. The rails are then lowered onto the tie plate, and new spikes are driven through the tie plates to anchor the rails to the tie.
Prior manual and machine based tie plate insertion techniques exhibit marked disadvantages.
In traditional manual-based tie plate insertion techniques, a winch or some other device is used to lift the rail from the tie sufficiently to provide clearance for a tie plate. Operators then place the tie plate on the tie adjacent the rails and push the tie plates beneath the rails, sometimes using a tool. Such manually operated tools are disclosed in U.S. Pat. Nos. 3,882,785 to Rowe and 6,595,140 to Madison et al. Inserting tie plates using such tools is very labor intensive, adding significantly to the cost of a tie replacement operation. It is also very time consuming—undesirably increasing the time that a railway is out of service for track maintenance operations.
Other machines have been proposed that position and insert tie plates, either in a stand-alone basis or as part of a larger machine that performs other track maintenance operations. These machines are disclosed, for example, in U.S. Pat. Nos. 5,067,412 to Theurer et al.; 5,655,455 to Smith; and 6,158,353 to Theurer. All three of these machines dispense tie plates from a magazine, position the tie plate adjacent the rail, and drive the tie plate beneath the rail using a complex structure. These machines are very complex and expensive to operate. They also have reliability issues resulting from their complexity. They are also relatively slow. Their insertion tools also lack the freedom of movement required to reliably insert a previously positioned tie plate beneath a rail.
The need therefore has arisen to provide a tie plate inserting machine that is relatively simple to operate yet is capable of reliably and rapidly inserting a prepositioned tie plate beneath a rail.
In accordance with a first aspect of the invention, a tie plate inserting machine is provided that inserts prepositioned tie plates beneath the rails of a railway. The machine includes a track mounted chassis, a workhead mounted on the chassis, and a tie plate inserter assembly mounted on the workhead. The tie plate inserter assembly includes a pusher that is driven by hydraulic cylinders or other powered actuators to move vertically, longitudinally, and laterally relative to the railway so as to be aligned with the stationary tie plate and to push the tie plate beneath the rail. In a preferred embodiment, the tie plate inserter assembly additionally includes a frame that supports the pusher. The frame is movably mounted on the workhead so that it is movable laterally of the railway. The pusher is able to move on the frame vertically and longitudinally relative to the railway. The pusher preferably includes a push plate that extends longitudinally relative to the railway and that selectively engages a field end of the tie plate and pushes the tie plate under the rail. It may additionally include a clamp that can selectively clamp the sides of the tie plate to accommodate tie plate misalignment or tie tilting. The machine also preferably includes a rail clamp assembly and jack that lift the rail from the tie during the tie plate insertion process. It may also include a mechanism that prevents the tie plate from being pushed too far beneath the rail. That mechanism may comprise a limit switch or other sensor and/or a hard stop that is located on the gauge side of the rail and that serves as a backstop against which the tie plate is driven during the insertion process.
In accordance with another aspect of the invention, a method is provided of inserting a previously positioned tie plate beneath a rail using a tie plate inserting machine. The method includes placing a tie plate on a tie outboard of a field side of the rail, then moving the tie plate inserting machine to a position which a pusher of the machine is located in the vicinity of the tie plate, and then actuating one or more power actuators to align the pusher with the tie plate and push the tie plate beneath the rail. The tie plates typically will be placed on the tie manually prior to the moving step as part of a tie replacement process. The actuating step may comprise actuating a first actuator to drive the pusher longitudinally of the railway to a position to which the pusher is at least generally aligned with the field end of the tie plate, actuating a second actuator to drive the pusher vertically so that the pusher is at least generally aligned with the tie plate, and then actuating a third actuator to drive the tie plate laterally under the rail.
Other aspects and advantages of the invention will become apparent to those skilled in the art from the following detailed description and the accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications could be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
A preferred exemplary embodiment of the invention is illustrated in the accompanying drawings in which:
As indicated in the Summary portion above, the invention relates to a track mounted machine that is capable of inserting a previously positioned tie plate between a rail and underlying cross tie of a railway. The machine preferably is also capable of lifting the rail from the tie prior to tie plate insertion and/or, is capable of operating on both rails of a railway simultaneously. The preferred embodiment includes two tie plate inserter assemblies mounted on a common workhead. Each tie plate inserter assembly includes a pusher that can be moved, under control of an operator stationed on the machine, vertically and longitudinally of the rails so as to be aligned with a field end of the tie plate. The pusher can then be actuated to push the tie plate laterally under the rail. A variety of machine configurations are capable of operating in this manner. One especially preferred embodiment will now be described.
Referring initially to
The workhead 28 includes a support frame 40, an inserter support carriage 42 mounted on the frame 40 for movement therealong laterally of the rails R, and left and right tie plate inserter assemblies 44L, 44R mounted on the inserter support carriage 42, each of which is operative to insert tie plates P between a tie T and an associated one of the left and right rails R.
The frame 40 includes left and right vertically spaced struts 46, 48 and upper and lower cylindrical support beams 50, 52 affixed to the ends of the struts 46, 48 to form a rectangular structure. The struts 46, 48 are mounted for vertical movement along the chassis by left and right sets of upper and lower roller assemblies 54, 56, each of which is mounted on an associated vertical strut 46, 48 of the frame 40. Each set of roller assemblies 54, 56 rides along a vertical rail 58, 60 on a support frame 62 of the chassis 22. This vertical movement is effected via a pair of hydraulic cylinders 64, 66, each of which has a rod end 70 attached to an associated strut 46, 48 and a barrel end 72 attached to a cantilevered support 74 located above the rails 58, 60. Each cylinder 64, 66 can be selectively extended and retracted to lower the workhead 28 from a raised, transport position to a lowered, operative position. It should be noted that the cylinders 64, 66 are extended during normal use of the machine 20, i.e., as the machine travels from tie to tie, and is raised only when the machine 20 is transported to or from the worksite. When the workhead 28 is lowered by cylinder extension, it is partially supported and guided on the rails R during insertion operations by rollers 76 mounted on the inserter support carriage 42.
As best seen in
Each side of the workhead 28 preferably incorporates mechanisms to lift the rail R from the tie T during a tie plate insertion operation. Referring to
Referring particularly to
Referring to
The left and right tie plate inserter assemblies 44L, 44R are preferably of identical construction. As best seen in
Referring to
Referring to
Still referring to
Referring now to
It should be noted at this point that the clamp assembly 198 is not in any way critical to the design. Indeed, it often remains open during normal operation. It is generally used only when the tie plate P is skewed on the tie T and/or the tie T is tilted.
The tie plate inserting machine 20 preferably incorporates measures to prevent the pusher 158 from driving a tie plate P too far beneath the rail R. For instance, limit switches or optical sensors could be provided for this purpose. In the preferred embodiment, however, a backstop or “hard stop” is provided. Referring to
As mentioned briefly above, the tie plate inserting machine 20 is controlled via operator manipulated controls 36 located adjacent the seat 34. These controls include left and right joysticks, the right one 260R of which is seen in
Referring to
The toggle switches 262 and 264 are proportional in nature such that each successive toggle moves the associated cylinder 155 and 122 an additional increment. Conversely, actuation of the push button switches 266 and 268 merely triggers an automatic operation such as complete cylinder retraction, complete cylinder extension and/or cylinder pressurization up to a preset limit. The triggers 270 can be actuated as an alternative to individually manipulating the switches 264 and 266. That is, by simultaneously actuating the triggers 270 and the push button switch 266, the rail clamping operation and rail lifting operation are performed automatically and sequentially without any other operator input. The operator holds the triggers 270 until the tie plates P are installed and then releases the triggers 270 to automatically retract the jack 94 and unclamp the rail R. The release of the triggers 270 also returns all cylinders to return the inserter assembly 44R to its retracted or home position. In this case, the jack extend switch 264 acts as an override switch that overrides the automatic operation initiated by the trigger to assure adequate jack extension should the jack 94 encounter an obstruction during the automatic operation.
Other controls, such as those required to actuate the cylinders 64 and 66 to raise and lower the workhead 28, while not shown, may comprise switches, levers, or any other suitable controls available to those skilled in the art.
The tie plate inserting machine 20 as described above operates as follows when used in tie replacement setting.
First, the operator transports the machine 20 to the worksite with the workhead 28 in its travel position due to the retraction of cylinders 64 and 66. Prior to this operation, laborers and/or one or more machines would have removed the old ties T from the railway, inserted the new ties T, and cleaned ballast or other debris from the top of the ties T. Importantly, and unlike with prior tie plate inserting machines, new or used tie plates P are also set on the ties T adjacent the field side of the rails R prior to insertion of the tie plate by the tie plate inserting machine 20. This setting may occur either well in advance or just ahead of operation of the tie plate inserting machine 20.
Upon arrival at the worksite, the operator extends the cylinders 64, 66 to lower the workhead 28 to its travel position in which the rollers 76 rest on top of the rails R. At this time, the cylinders 168, 148 are in positions in which the pusher is raised away from the tie T and is positioned well outboard of the field end of the tie plate P, and the tie plate clamp assembly 198 is open. Next, the operator stops the machine 20 in a position in which the workhead 28 is at least approximately centered over the tie T. This centering may be performed manually by inspection or with the assistance of sensors such as a laser-based sensor. At this time, the hard stop 230 is positioned inboard of the gauge side of the rail R in general alignment with the gauge end of the tie plate P. The spacing between the hard stop 230 and the rail R is set by suitable actuation of cylinder 254. However, as indicated above, this actuation is not performed on a cycle-by-cycle basis but, instead, is a “set and forget” function that sets the spacing for a given tie plate and tie configuration.
The operator then engages the triggers 270 of both joystick to first engage the associated rail clamp 92 and then extend the jack 94 to lift the rails R to the position seen in
Next, the operator moves each joystick 260 inboard to move the pusher 158 toward the associated tie plate P. If desired, the operator may operate the switch 266 to close the tie plate clamp assembly 198 as the push plate 196 approaches the field end of the tie plate P so as to accommodate a skewed tie plate P and/or a tie T that is tilted about its longitudinal center line. As indicated above, tie plate tilting is also accommodated by passive swinging of the pusher 158 about pin 186.
Next, the operator moves each joystick 260 inboard so that the push plate 196 first engages and then pushes to the associate tie plate P beneath the rail R until the gauge end of the tie plate contacts the pins 234 and 236 of the hard stop 230 to arrest further tie plate movement as seen in
The process as described above is very reliable and can be performed very rapidly due to the fact that the insertion process is automatic, yet no complex dispensing and transport mechanisms need be activated to set a tie plate P adjacent the rail R. Indeed, experiences has shown the entire process, from engagement of the rail clamp, through tie plate insertion, and to release the rail clamp can be performed in under 10 seconds and, in fact, in as little as 5-7 seconds. This is a dramatic improvement over prior known machines.
As indicated above, many changes and modifications may be made to the present invention without departing from the spirit thereof. The scope of some of these changes is discussed above. The scope of others will become apparent from the appended claims.
