Abstract:
A railroad ballast removal system capable of removing ballast material from below a rail line. The railroad ballast removal system includes at least one rotary cutting wheel having a plurality of individually replaceable cutting attachments positioned about a perimeter of the rotary cutting wheel. Each rotary cutting wheel is attached to an articulated arm capable of adjusting the position of the rotary cutting wheel along varying axis. The articulated arm is mounted to a support structure capable of transporting the rotary cutting wheel to a portion of railway requiring maintenance of the ballast material. The railroad ballast removal system is able to operate at a spot location or in a continuous manner down a length of railroad track. The ability to manipulate the rotary cutting wheel along the various axis allows the rotary cutting wheel to be used for ballast removal in locations wherein adjacent railways limit cutting access.

Description:
PRIORITY CLAIM 
     The present application claims priority to U.S. Provisional Application Ser. No. 61/180,673, filed May 22, 2009 and entitled, “ROTARY UNDERCUTTER FOR RAIL LINE MAINTENANCE”, which is herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to railroad maintenance systems. More specifically, the present invention is directed to a rotary undercutting system for use in removing ballast material from below a railroad track. 
     BACKGROUND OF THE INVENTION 
     The maintenance of railroad track ballast is an ongoing and important element of railroad transportation safety. The ballast material associated with railroad track lines, typically crushed rock or gravel, helps to provide horizontal and vertical support to the railroad line and also provides a drainage mechanism to help remove damaging moisture away from the railroad track and ties. Periodically, the ballast along a length of track, or in single spot locations, may become fouled with dirt, oil, debris, or other matter that can reduce the draining properties or supporting ability of the ballast. Therefore, railroad operators must periodically replace or recondition this fouled ballast in order to maintain the integrity and safety of the railroad line. The repair of rail line ballast is not easily accomplished with traditional earth-moving equipment. The rail and tie configuration of railroad lines requires the use of specialized equipment if the rail and tie assembly is to remain in place during reconditioning. Because of the time and cost involved in removing and constructing railroad lines, it is highly desirable to leave the rail line in place during reconditioning and to minimize or eliminate the time when the line is unavailable for rail traffic. 
     Currently in the marketplace, there are a variety of machines and techniques for removing railroad track ballast. For example, one approach is to remove a short section of track ballast and insert a plow or sled towed by a specially equipped railcar to push or force the ballast to the outside edges of the track. A second example of a ballast removing device is a “chainsaw” type mechanism where a long blade supports a rotating chain or belt that can be manipulated to “cut” ballast out from underneath the rails and ties of an existing track. Representative prior art maintenance and removal systems for railroad ballast include U.S. Pat. Nos. 3,967,396, 4,119,154, 4,858,344, and 6,862,822, each of which is herein incorporated by reference. 
     Generally, the plow or sled approach for removing ballast is limited to situations where a long stretch of track is to be reconditioned due to the fact that the effort required to initially place the plow under the rail line is not typically justifiable for short segments of track. While the chain equipped ballast cutter may be more suitable for short distance ballast removal it can be subject to chain or belt breakage requiring maintenance to replace or repair of the cutting assembly. Thus, neither of these existing technologies satisfies the need for a ballast removing apparatus capable of being reliably and cost effectively used for both short and long distance ballast removal. 
     In certain track layout configurations it is also inconvenient to use either the ballast plow or a large chain driven cutting apparatus. For example, in areas such as rail yards, sidings, and other locations where multiple lines run in parallel to each other in close proximity it can be difficult to maneuver a large cutting machine into position between the rail lines or there may be inadequate space on either side of the railroad line to deposit the fouled ballast as it is removed from underneath the rails. 
     Therefore, an unsolved need exists for further improvement to existing railroad ballast removing systems. The system should be able to quickly and effectively remove ballast from underneath existing rail lines and to provide an easily maneuverable cutting or cutting apparatus that is capable of operating in restricted areas. Additionally, the system should be configured such that the risk of breakage is minimized and such that it is easily maintained or serviced when necessary. By eliminating the use of a belt or chain assembly maintenance time and cost can be reduced, further reducing costs associated with rail line maintenance and reconditioning. 
     SUMMARY OF THE INVENTION 
     In order to address the needs described above, a representative ballast-removal system according to the present invention comprises a pair of rotating cutters attached to a rail platform or alternatively, a stand-alone vehicle, by a pair of multi-jointed arms or boom assemblies capable of positioning the cutters as needed. The ballast removal system of the present invention involves fewer parts than existing ballast cutting systems, thereby reducing downtime associated with part replacement while providing a greater degree of flexibility in positioning the cutters. The ballast removal system described here is capable of being installed to work with existing ballast reconditioning systems where multiple machines are connected in order to remove, filter, and replace fouled ballast. 
     In one aspect, the present invention is directed to a rotary cutting head that is attached to an articulatable mechanical arm or manipulator for ease of positioning and excavation of railroad track ballast. The rotary cutting head can comprise a plurality of individually replaceable cutting elements. 
     In another aspect, the present invention is directed to a method of removing railway ballast material. A first step can comprise providing one or more of a rotary cutting head attached to an articulatable mechanical arm. A second step can comprise manipulating the rotary cutting head with the articulatable mechanical arm to cut into the railway ballast. A third step can comprise operating the at least one rotary cutting head below the railway to remove the railway ballast. In one preferred method of removing railway ballast material, a pair of rotary cutting heads, each being provided on its own articulatable mechanical arm, are provided to operate below the railway for removing the railway ballast material. 
     In another aspect, the present invention is directed to a system comprising a pair of rotary cutting heads mounted together such that the two heads are oriented towards each other when excavating material. 
     In yet another aspect, the present invention is directed to a railroad ballast removal system including a pair of rotary ballast removing cutters, the cutters mounted on a pair of multi-axis mounting arms capable of movement with multiple degrees of freedom. The mounting arms can be removably attached to a specialized railcar or other mobile vehicle for use in clearing material to facilitate railroad line maintenance or construction. 
     In yet another aspect, the present invention is directed to a method of reducing an amount of space necessary to cut into a rail bed for removing ballast material. In some embodiments, the method can be practiced in railyards or other locations having at least a pair of railways located in proximity. 
     The above summary of the invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description that follow more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  is a front, perspective view of a rotary undercutter according to an embodiment of the present invention. 
         FIG. 2  is a bottom, perspective view of a rotary cutting wheel assembly according to a representative embodiment of the invention. 
         FIG. 3  is an exploded, bottom perspective view of the rotary cutting wheel assembly of  FIG. 2 . 
         FIG. 4  is an upper perspective view of the rotary cutting wheel assembly of  FIG. 2 . 
         FIG. 5  is an exploded, top perspective view of the rotary cutting wheel assembly of  FIG. 2 . 
         FIG. 6  is a front, perspective view of the rotary undercutter of  FIG. 1  where both rotary cutting wheels are positioned under an existing rail line. 
         FIG. 7  is a rear, perspective view of the rotary undercutter of  FIG. 6 . 
         FIG. 8  is a top, perspective view of a pair of internal gear components of the rotary cutting wheel assembly of  FIG. 2 . 
         FIG. 9  is a rear, perspective view of a rotary undercutter of the present invention configured in conjunction with a track lifter assembly. 
         FIG. 10  is a top, perspective view of an internal assembly of the rotary cutting wheel assembly of  FIG. 2 . 
         FIG. 11   a  is a side view of the rotary undercutter of  FIG. 1  operating on a track with an adjacent rail line. 
         FIG. 11   b  is a front view of the rotary undercutter of  FIG. 11   a.    
         FIG. 12   a  is a side view of the rotary undercutter of  FIG. 1  cutting under a track with an adjacent rail line. 
         FIG. 12   b  is a front view of the rotary undercutter of  FIG. 12   a.    
         FIG. 13   a  is a side view of the rotary undercutter of  FIG. 1  removing ballast on a track with an adjacent rail line. 
         FIG. 13   b  is a front view of the rotary undercutter of  FIG. 13   a.    
         FIG. 14  is a side view of a rotary undercutter operably attached to an engineering vehicle for off-track operation according to an embodiment of the present invention. 
         FIG. 15  is a plan view of the rotary undercutter of  FIG. 14 . 
     
    
    
     While the present invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the present invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1 , a representative embodiment of a rotary undercutter  100  is shown mounted to a support structure  102  suspended between two railcar carriages (not depicted). The rotary undercutter  100  is suspended above a rail line  103  including pair of rails  104  and rail ties  106  that have been lifted above their ballast  108 . As shown in  FIG. 1 , rotary undercutter  100  can include a pair of cutting wheel assemblies  110  with one shown disposed in an elevated position  111  while the other is shown in an operating position  113  below the rails  104 . Each cutting wheel assembly  110  is individually manipulated and positioned by a corresponding multi jointed positioning arm  112 . The positioning arms  112  can include a non-limiting variety of hinges, couplings, joints, sliding mechanisms, actuators, hydraulics, motors, or the like, as needed to mount the cutting wheel assemblies  110  to support structure  102  or alternatively, directly to a vehicle and to allow the cutting wheel assemblies  100  to be oriented and positioned during use or transport. As illustrated throughout the figures, a pair of positioning arms  112  are generally illustrated in a substantially inline arrangement with respect to the support structure  102 . It will be understood, that in certain ballast maintenance arrangements, positioning arms  112  can be off-set or otherwise staggered along the support structure  102  to allow for cutting overlap to ensure complete cutting and ballast removal below the rails  104 . In some embodiments, support structure  102  can comprise a rail car intended solely for the removal of ballast  108  while in other alternative embodiments, support structure  102  can comprise a car configured with additional systems for cleaning and replacing ballast  108 . 
     As seen in  FIGS. 2 and 3 , the present embodiment of cutting wheel assembly  110  comprises a plurality of cutting attachments  114  mounted at the periphery or perimeter rim of a rotating cutting wheel  116 . Each cutting attachment  114  is individually, removably attached to the rotating cutting wheel  116  in order to facilitate the replacement of individual cutting attachments  114  in the event of breakage or excessive wear. The cutting attachment  114  can comprise a tooth configuration, or alternatively, configurations such as, for example, shovels, paddles, and the like are contemplated. It is envisioned that the number of individual cutting attachments  114 , and the corresponding space between them around the perimeter of the rotating cutting wheel  116 , can be varied depending on the diameter of the rotating cutting wheel  116 , the consistency of the support ballast  108  that is to be removed and desired speeds of rotation and advancement of the rotary undercutter  100  along the rail line  103 . 
     Cutting wheel assembly  110  generally comprises a plurality of rings including an upper ring  118 , a lower ring  120  and a central drive ring  122 . The upper ring  118  and the lower ring  120  are layered on the central drive ring  122  and coupled together with fasteners  124  passing through the central drive ring  122 . The upper ring  118  and the lower ring  120  can provide attachment points  126  for the cutting attachments  114 . The cutting attachments  114  can be removably fastened to the upper ring  118  and the lower ring  120  with threaded bolt fasteners  128  or any other appropriate fastening mechanisms. 
     The cutting wheel assembly  110  also includes a drive motor  130  located on the top side of the cutting wheel assembly  110 . A mounting bracket  132  having mounting points  220 , along with an actuation bracket  136  are attached to a drive column  138  that can provide support for the drive motor  130 . The drive column  138  is offset from the center of the cutting wheel assembly  110  and is generally located near the perimeter of the cutting wheel assembly  110  such that a majority of the cutting wheel assembly  110  can be positioned under the rail  104 . By eliminating any interference with the drive column  138  and rail  104 , the overall size of the cutting wheel assembly  110  necessary to clear a given area of ballast  108  can be reduced. 
     Support and drive mechanisms for cutting wheel assembly  110  are generally illustrated in  FIG. 3 . A lower disk  140  provides a plurality of mounting points for bogey wheels  142  that are located inside the upper ring  118 , lower ring  120  and central drive ring  122  forming the cutting wheel assembly  110 . The bogey wheels  142  can support and stabilize cutting wheel assembly  110  and provide structural rigidity to an upper disk  144  and the lower disk  140 . The lower disk  140  can be connected to the upper disk  144  by a central hub  146  at a plurality of securement points  148  as well as by the axels  150  of the bogey wheels  142 . The axels  150  of the bogey wheels  142  are secured to the lower disk  140  and the upper disk  144  at fixed locations  152 , providing a uniform guide for the cutting wheel assembly  110  to travel about a central axis  154 . 
     Drive motor  130  is coupled to a drive shaft  156  in order to provide rotational torque to the cutting wheel assembly  110 . The drive shaft  156  is supported in the drive column  138  by bearing assembly  158  located in lower opening  160  of the upper disk  144 . The drive shaft  156  is coupled to a drive gear  162  by bushing  164 . The drive gear  162  interfaces with the internal gear  166  that can be disposed on or formed by the central drive ring  122 . Drive motor  130  can be driven by a generator that is operably positioned on support structure  102 . 
     Referring now to  FIGS. 4 and 5 , a top view of the cutting wheel assembly  110  is depicted. The upper disk  144  can be located inside an interior lip  168  of the upper ring  118  such that the rotary cutting wheel  116  can ride along the perimeter of the upper disk  144 . Likewise, the lower ring  120  can ride along the perimeter of the lower disk  140 . Interior lip  168  can be formed in the material comprising the upper and lower rings  118 ,  120  or alternatively the central drive ring  122  can have a greater thickness than the upper ring  118  and the lower ring  120 . This can be embodied in a central drive ring  122  with a smaller internal diameter than the internal diameter of the upper ring  118  and the lower ring  120 . As shown in this example embodiment, the outer diameter of the central drive ring  122 , the upper ring  118  and the lower ring  120  are generally equal, with the exception of the areas in the upper ring  118  and the lower ring  120  that form the attachment points  126  for the cutting attachments  114 . 
     The drive gear  162  is depicted in  FIG. 5  as meshing with the internal gear  166 . As previously discussed, the bushing  164  and bearing assembly  158  allow the coupling of the drive motor  130  to the drive gear  162  through the drive shaft  156 . The drive column  138  in this embodiment is not wholly circular. Below an upper opening  170  that provides a mounting point for the drive motor  130  is a generally flat face  172  directed toward the central axis  154  of the cutting wheel assembly  110 . While the drive column  138  must provide sufficient clearance for the location of the drive shaft  156  between the motor  130  and the drive gear  162 , the flat face  172  can help to provide a greater operating range for the cutting wheel assembly  110  as the flat face  172  can pass along the edge of the rail ties  106  at a minimum distance. 
       FIGS. 6 and 7  depict an exemplary embodiment of positioning arms  112  that can be used to connect the cutting wheel assemblies  110  to support structure  102 , or other appropriate support structures positioned over a set of rails  104 . The use of the multi-jointed positioning arm  112  enables the actuation of the cutting wheel assemblies  110  about a plurality of axis. In the example embodiment the cutting wheel assemblies  110  can be adjusted for roll, pitch, yaw, and horizontal or vertical positioning. In this example embodiment depicted there are five unique axis of movement defined by the plurality of supports and actuators and will be discussed numerically. 
     A first rotational axis  174  can be provided by a carriage  176  that can provide a mounting point  178  for each of the pair of positioning arms  112 . The carriage  176  can pivot or roll about the first rotational axis  174  when mounted to an attaching bracket  180 . In addition, the carriage can adjust both positioning arms  112  for cross-level cutting as may be appropriate and necessary for super-elevated curves. The attaching bracket  180  can comprise a central shaft  182  or other appropriate structure for providing first rotational axis  174  parallel to the path of rails  104 . The carriage  176  can be rotated about first rotational axis  174  by a pair of first-axis actuators  184  that can be located at the edges of carriage  176  and attaching bracket  180 . The first-axis actuators  184 , and any of the other actuators to be discussed below, can be driven by hydraulic pressure, or other appropriate force such as pneumatics, through a plurality of hoses or control lines, not depicted here for clarity. As understood by those skilled in the art, the placement of the hoses or control lines necessary to operate the rotary undercutter  100  is an important consideration, but not critical to the overall design of the present invention. 
     A second rotational axis  186  providing horizontal movement for each positioning positioning arm  112  is located at the interface of the mounting point  178  of the carriage  176  and a shoulder coupler  188  that rotatably joins one end of a pair of primary beams  190  together. At an opposite end of each of the pair of primary beams  190 , the cutting wheel assembly  110  is rotatably joined to the cutting wheel assembly  110  with a wrist coupler  192 . The second rotational axis  186  provides for one or both of the cutting wheel assemblies  110  to be moved towards or away from a central line between the rails  104  allowing movement for initial positioning of the cutting wheel assemblies  110 , during the operation of the rotary undercutting system  100  to remove ballast  108 , or for extraction of the cutting wheel assemblies  110  at the completion of a task. In addition, the second rotational axis  186  allows the cutting wheel assemblies  110  to be shifted to accommodate cutting at railway curves where rails  104  shift, in some situations by an amount of up to 2 feet, relative to the support structure  102 . A pair of second axis actuators  194  can be attached to an interior surface of each primary beam  190  to provide horizontal movement. 
     A third rotational axis  196  providing vertical positioning of the cutting wheel assemblies  110  can be achieved by manipulating the pair of primary beams  190  with a set of vertical manipulators  198 . As shown in  FIGS. 6 and 7  the vertical manipulators  198  can be positioned on the interior and exterior surfaces of the primary beams  190 . While the example embodiment depicted here utilizes a pair of primary beams  190 , alternative configurations are contemplated where only a single primary beam in conjunction with an appropriately configured manipulator or manipulators can accomplish the vertical positioning of the cutting wheel assemblies  110 . 
     A fourth rotational axis  200  at the wrist coupler  192  provides independent roll adjustment of each of the cutting wheel assemblies  110 . A top housing  202  can be connected to the wrist coupler  192 , and forms the fourth rotational axis  200  at the interface between the top housing  202  and a lower housing  204 . A fourth axis actuator  206  can be removably connected to the top housing  202  and the lower housing  204  with a plurality of mounting brackets  208 . 
     The independent control of the roll position of each of the individual cutting wheel assemblies  110  is advantageous for the removal of ballast  108  from sections of rail line  103  where one rail  104  is located vertically, or superelevated, above the other rail  104 , such as in a banked turn or curve. The combination of the independent vertical positioning of the primary beams  190  and the fourth rotational axis  200  at the wrist coupler  192  provide an operator of the rotary undercutter  100  to remove only the appropriate ballast  108  from each side of the rail line  103 . This combination also helps the operator of the rotary undercutter  100  avoid potentially damaging contact between the cutting wheel assemblies  110  and the rail ties  106 . 
     A fifth rotational axis  210  provides independent yaw adjustment of the cutting wheel assemblies  110 . A yaw actuator  212  connecting the lower housing  204  and the actuation bracket  136  provides for the yaw or horizontal positioning of the cutting wheel assemblies  110 . This horizontal positioning can be used to adjust the depth of the cut into the ballast  108  during the operation of the rotating cutting wheel assemblies  110 . The cutting wheel assemblies  110  on each side of the rotary undercutter  100  can be adjusted independently of the other, and can be positioned such that they nearly contact each other when centered underneath a set of rails  104  for effective removal of the ballast  108 . In addition, fifth rotational axis  210  increases safety and mechanical reliability by essentially allowing the cutting wheel assemblies  110  to function as a mechanical fuse, whereby the cutting wheel assemblies  110  can swing outward from rails  104  if hazards or other obstacles such as, for example, buried ties, tie plates or old rails, are encountered. 
       FIG. 8  depicts two unassembled examples of the central drive ring  122  configured to form the internal gear  166 . Flat portions  214  on the outer perimeter of the central drive ring  122  can provide a contact point for cutting attachments  114 . 
       FIG. 9  depicts one embodiment of the rotary undercutter  100  along with a rail track lifter  216  mounted to the support structure  102 . This configuration of equipment facilitates the efficient removal of ballast  108  from underneath rails  104 . 
       FIG. 10  depicts another embodiment of a cutting wheel assembly  110  showing the positioning of the bogey wheels  142  relative to the central hub  146  and the rotary cutting wheel  116 . In the place of the mounting bracket  132  as described previously, the illustrated embodiment depicts a reversible mount  218  that allows for a single cutting wheel assembly  110  to be mounted to either the right or left side of the rotary undercutter  100 . The reversible mount  218  includes a pair of mounting points  220  on either side of the drive column  138 . 
       FIGS. 11   a  and  11   b  depict an embodiment of a rotary undercutter system  100  positioned on rails  104  where a parallel track  222  runs adjacent to the rail  104 . This configuration of parallel rail lines is often encountered in rail sidings, switching yards and double or multiple track locations. As depicted in  FIG. 11   b , the multi-jointed positioning arm  112  closest to the parallel track  222  is suspended above the rail  104  such that the undercutter system  100  requires no more than the physical space of a typical rail car such that the undercutter system  100  is able to pass by a set of railcars (not depicted) on the parallel track  222  without contacting the railcars on the parallel track  222 . 
       FIGS. 12   a  and  12   b  depict an embodiment of a rotary undercutter system  100  where the multi jointed positioning arm  112  closest to the parallel track  222  is guiding the cutting wheel assembly  110  to cut into the ballast  108  under the rail  104 . This process is accomplished without interfering with the parallel track  222 . Unlike existing systems, the rotary undercutter system  100  of this embodiment is configured to remove ballast  108  with minimal disruption to any parallel track  222  located on either side of the rotary undercutter system  100 . 
       FIGS. 13   a  and  13   b  depict an embodiment of a rotary undercutter system  100  where the cutting wheel assemblies  110  are both positioned to remove the ballast  108  under the rail  104  after completion of the cut-in process depicted in  FIGS. 12   a  and  12   b . Likewise, the cutting wheel assemblies  110  can both be removed from underneath the rail  104  with minimal disruption to any parallel track  222 . 
     As illustrated in  FIGS. 14 and 15 , an embodiment of a rotary undercutter  200  can comprise cutting wheel assembly  110  operably coupled to an engineering vehicle such as, for example, an excavator  202  or alternatively, a backhoe or similar implement. Excavator  202  generally comprises an articulated boom  204  that provides the positioning abilities of multi-jointed positioning arm  112 . Excavator  202  can comprise an undercarriage  206  having a track assembly  208  or off-track operation, or alternatively, a rail wheel assembly allowing the excavator  202  to move along the rail line  103 . Generally, cutting wheel assembly  110  will include drive motor  130  that is powered directly off the engine/generator of excavator  202  or alternatively, a stand-alone generator assembly can be towed or otherwise positioned proximate the excavator  202  so as to supply the necessary power to drive motor  130 . 
     Rotary undercutter  200  can function in a manner similar to rotary undercutter  100  with the exception that one side of the rail line  103  is undercut first whereby the excavator  202  can be subsequently positioned on an opposing side to complete the undercutting work. Rotary undercutter  200  can be used in locations and situations where the use of the track supported rotary undercutter  100  is impractical. Some representative applications for rotary undercutter  200  can include short portions of rail line  103  requiring undercutting work or where the amount of undercutting work does not financially support a track supported rotary undercutter  100 . As excavator  202  can utilize a quick-coupler on the articulated boom  204 , a variety of attachments besides the rotary undercutter  100  can be used including, for example, buckets, compactors, pulverizers and hammers, thereby increasing the use of excavator  202 . 
     Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. Any incorporation by reference of documents above is further limited such that no claims included in the documents are incorporated by reference herein. Any incorporation by reference of documents above is yet further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein. 
     The foregoing descriptions present numerous specific details that provide a thorough understanding of various embodiments of the invention. It will be apparent to one skilled in the art that various embodiments, having been disclosed herein, may be practiced without some or all of these specific details. In other instances, known components have not been described in detail in order to avoid unnecessarily obscuring the present invention. It is to be understood that even though numerous characteristics and advantages of various embodiments are set forth in the foregoing description, together with details of the structure and function of various embodiments, this disclosure is illustrative only. Other embodiments can be constructed that nevertheless employ the principles and spirit of the present invention. Accordingly, this application is intended to cover any adaptations or variations of the invention. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof. 
     For purposes of interpreting the claims for the present invention, it is expressly intended that the provisions of Section 112, sixth paragraph of 35 U.S.C. are not to be invoked with respect to a given claim unless the specific terms “means for” or “step for” are recited in that claim.