Patent Publication Number: US-7587981-B2

Title: Method for cleaning ballast of a track

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Applicants claim priority under 35 U.S.C. §120 of International Application No. PCT/EP2005/050168 filed on Jan. 17, 2005. This application is a by-pass continuation application of said International Application No. PCT/EP2005/050168 filed on Jan. 17, 2005. The International application under PCT Article 21(2) was not published in English. The disclosure of the aforementioned International application is incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the invention 
   The invention relates to a method for cleaning ballast. More particularly, the invention relates to a method for cleaning ballast of a track comprising rails extending in a longitudinal direction, said method being carried out by means of a ballast cleaning machine. The machine has a machine frame supported on on-track undercarriages and includes a cleaning chain with a chain cross member extending perpendicularly to the longitudinal direction. 
   The invention also relates to a machine for carrying out said method. 
   2. The Prior Art 
   An article in the the trade journal “Eisenbahningenieur” (52) 8/2001, page 81 (“New cleaning chain for ballast bed cleaning machine RM 800”) describes a method of this type. According to this method, the track has to be severed at the start of cleaning in order to be able to position a chain cross member of a special, very efficient cleaning chain of a ballast cleaning machine in the ballast bed underneath the track. A machine of this type is known, for example, from U.S. Pat. No. 5,926,981. During working operations of this machine, the machine frame is supported at each end on the track by means of a respective on-track undercarriage. According to a further version, visible in  FIG. 2  of said patent disclosure, the on-track undercarriage situated in front of the cleaning chain, with regard to a working direction of the machine, can be distanced from the chain during working operations. 
   According to U.S. Pat. No.  4 , 538 , 687 , it is known to lift an on-track undercarriage, positioned immediately ahead of the cleaning chain of a ballast cleaning machine, permanently off the track during working operations. As a result, it is possible even in this section to impart to the track a deflection curve necessary for lifting the track. The raised on-track undercarriage merely serves for mobility of the machine during transfer travel in order to be able to move or guide the machine within the track clearance profile. 
   SUMMARY OF THE INVENTION 
   It is the primary object of this invention to improve a method and machine of the first-described type which will allow the chain cross member of the chain to be positioned underneath the track in a problem-free manner also on machines of shorter length. 
   This object is accomplished in accordance with the invention with a method for cleaning ballast of a track, comprising rails extending in a longitudinal direction, by means of a ballast cleaning machine. Said machine has a machine frame supported on on-track undercarriages and includes a cleaning chain with a chain cross member extending perpendicularly to the longitudinal direction. At the start of the cleaning process, according to the method disclosed, an on-track undercarriage situated immediately ahead of the cleaning chain, with regard to a working direction of the ballast cleaning machine, is lifted off the track, and the rails are severed. Then the track is lifted, the chain cross member of the cleaning chain is positioned underneath the track, and the on-track undercarriage is set down upon the track again. 
   This method is particularly suited for machines intended especially for working operations in track sections having tight curve radii. With the temporary lifting of the undercarriage positioned at the front end of the machine frame, while the severed track section situated in front in the working direction is raised, the chain cross member can automatically work itself deeper into the ballast bed until the desired working position is reached. For the subsequent working operation, the front on-track undercarriage is lowered upon the track again. Likewise, after finishing the working operation, the chain cross member can be lifted out of the track again by carrying out the said steps in reverse order. Despite a shorter length of the machine, this method makes it possible to advantageously arrange the screening plant immediately following the cleaning chain. 
   The object of the invention is also accomplished with a ballast cleaning machine comprising a machine frame having a front end and a rear end with regard to a working direction of the machine. On-track undercarriages are arranged at the front end and the rear end, respectively. A vertically adjustable endless cleaning chain is positioned between the two on-track undercarriages, and a vertical adjustment drive is provided between the front end of the machine frame and a rear end of a further machine frame arranged preceding said front end in the working direction. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other benefits and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
     In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
       FIG. 1  shows a side view of a ballast cleaning machine immediately prior to a cleaning operation; and 
       FIG. 2  shows a side view of the machine during the cleaning operation. 
   

   DETAILED DESCRIPTION OF THE DRAWINGS 
   Referring now in detail to the drawings,  FIGS. 1 and 2  show a machine  1  for cleaning ballast  5  of a track  8  having rails  23  extending in a longitudinal direction. The machine  1  comprises a machine frame  2  having two ends  3  spaced from one another with respect to said longitudinal direction. At each end  3 , a respective on-track undercarriage  4  is arranged. An endless cleaning chain  7 , designed to be set in rotation by means of a drive  6 , has a chain cross member  9  positioned underneath the track  8  and extending perpendicularly to the longitudinal direction of the machine during working operations. Arranged above said chain cross member  9  is a track lifting device  11  which is vertically adjustable by means of a drive  10 . 
   On the machine frame  2 , a screening plant  12  having a discharge conveyor belt  13  is provided for cleaning the ballast  5 . Arranged at the front end  3  of the machine frame  2 —with respect to a working direction indicated by arrow  19 —is a work cabin  14  with a control unit  15 . At the rear end  3 , a driver&#39;s cab  16  is situated, including a conveyor belt  17  for supplying new ballast as needed. Spoil accumulating as a result of the ballast cleaning operation is removed with the aid of a conveyor belt arrangement  18 . 
   Fastened to the front end  3  of the machine frame  2  is a hydraulically vertically adjustable ram, or vertical adjustment drive  20 , which can be supported on a further machine frame  21  situated at the front in the working direction  19 . On said further machine frame, a power unit  22  for supplying energy to the machine  1  is located. 
   At the start of the working operation (see  FIG. 1 ), the hydraulic ram or vertical adjustment drive  20  is actuated, causing the front end  3  of the machine frame  2  to be lifted and thus also the front on-track undercarriage  4  to be raised off the track  8 . Subsequently, both rails  23  of the track  8  are severed, and a track section, situated forwardly in the working direction  19 , of the severed track  8  is raised with. the aid of an auxiliary lifting device  26  until the chain cross member  9  can be positioned without problems between the raised front track section and the lower track section. With actuation of the drive  6 , the chain of the cleaning chain  7  is set in rotation, and the latter is lowered by means of drives  24  in parallel with a slow advance of the machine  1  in the working direction  19 . In this manner, the chain cross member  9  automatically digs itself into a ballast bed  25  until the desired position underneath the track level is reached ( FIG. 2 ). 
   The two severed rails  23  are subsequently connected to one another by means of fish-plates. The front on-track undercarriage  4  is lowered upon the track  8  again by retraction of the ram or vertical adjustment drive  20 . While the two machine frames  2  and  21  coupled to one another advance in the working direction  19 , the continuous process for cleaning the ballast  5  now begins. After termination of the cleaning process, the rails  23  are disconnected again, and the front on-track undercarriage  4  is lifted again in order to be able to raise the chain cross member  9  for transfer travel of the machine  1 . 
   Accordingly, while an embodiment of the present invention has been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.