Patent Publication Number: US-6698115-B2

Title: Clearing chain for excavating bulk material

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the priority of Austrian utility model document GM 24312001, filed Apr. 2, 2001, pursuant to 35 U.S.C. 119(a)-(d), the subject matter of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a clearing chain for excavating bulk material from a ballast bed supporting a track and for conveying the excavated bulk material, and more particularly to a clearing chain of a type including a plurality of shovel-type clearing members sequentially arranged in the direction of elongation of the chain for gathering and moving along the bulk material, the chain being mounted on a frame of a mobile track working machine. 
     U.S. Pat. No. 4,614,238 discloses an articulatedly constructed clearing chain of this type which is composed of a multitude of similarly formed chain elements connected to one another by means of respective chain joints. Every third chain element is connected by means of a screwed connection to a clearing element designed for excavating or collecting bulk material. The chain joints are shaped as universally movable cross joints. Such a flexible clearing chain can be guided in a three-dimensional path; however, the structural design required for this purpose is relatively complicated. 
     It would therefore be desirable and advantageous to provide an improved clearing chain which obviates prior art shortcomings and which, while retaining the feature of universally movable joints, can be manufactured in a simple manner. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a clearing chain includes intermediate chain elements positioned in each case between two adjacent clearing members for forming an endless chain, each intermediate chain element including two chain joints spaced from one another in the direction of elongation of the chain, each chain joint having a joint axis; and hinge pins for hingedly connecting the clearing members and intermediate chain elements to one another at each chain joint, the hinge pins being releasably fastened to the clearing member and articulatedly mounted in the chain joint. 
     This particular design of the clearing chain, being composed of clearing members and intermediate chain parts alternatingly following one another in the direction of longitudinal extension of the chain, already results in a simplification of the structural complexity of the chain. An additional advantage is due to the circumstance that the individual clearing members have no moving or articulated parts and therefore can be manufactured in a simple manner, producing a sturdy component which is particularly suited for robust use under diverse conditions. 
     Preferably, the chain joint includes a joint bearing designed as a spherical bearing, including a knuckle eye and a ball race which is universally movably mounted in the knuckle eye and surrounds the hinge pin extending in the direction of the joint axis. This feature provides the required degree of flexibility to guide the chain in a three-dimensional manner while ensuring simplicity and robustness of design. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which: 
     FIG. 1 is a simplified side view of a track working machine according to the present invention having a clearing chain for excavating ballast situated underneath a track; 
     FIG. 2 is a fragmentary, partially sectional view of the chain; 
     FIG. 3 is a detailed top view of a chain element; 
     FIG. 4 is a detailed top view of a clearing member; and 
     FIG. 5 is a cross-sectional view of the clearing chain. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals. 
     Turning now to the drawing, and in particular to FIG. 1, there is shown a simplified side view of a track working machine  1  which has a machine frame  5  supported on undercarriages  2  for mobility on a track  3 . The track is comprised of rails fastened to ties resting on ballast  9  forming a track bed. The operating direction of the machine is indicated by arrow  31 . At the rear end of the machine  1 , with regard to the operating direction, a clearing chain  4  for excavating bulk material is mounted for vertical adjustment on the machine frame  5 . In operation, the endless clearing chain is guided around the track  3 , with an excavating section  7  of the chain passing underneath the track and being positioned in the ballast bed. In its upper region, the clearing chain  4  has an ejection end  6  positioned above a receiving end of a conveyor belt  8  for transporting excavated ballast  9  to a bulk material loading wagon  10  coupled to the machine  1 . Between the excavating section  7  and the ejection end  6 , the clearing chain  4  is guided in a curved guide track  11 . This ensures that ballast  9  can be gathered underneath the track  3  and transported upwards to the conveyor belt  8  in an optimal manner even under the most confined spatial conditions. 
     As shown in detail in FIG. 2, the clearing chain  4  is composed of clearing members  12  and intermediate chain elements  13 , arranged alternatingly in the direction of longitudinal extension, or longitudinal direction  15 , of the chain  4  and connected to one another in each case by means of a respective chain joint  14  having a joint axis  19 . Each clearing member  12  is equipped with finger-shaped engaging elements  29  and a shovel part  30  which cooperate to gather and move along the ballast material to be excavated. 
     Each intermediate chain element  13  comprises a main portion  22  which is positioned in a plane  23  extending perpendicularly to the joint axis  19 . The main portion  22  includes two chain joints  14  spaced from one another in the longitudinal direction  15  of the clearing chain  4 . Each chain joint  14  is designed as a joint bearing  16  which is rotatable in all directions. To that end, the joint bearing  16  is shaped as a spherical bearing having a knuckle eye  17  in which a ball race  18  is freely movably mounted. The ball race  18  surrounds a hinge pin  20  the pin axis of which coincides with the joint axis  19 . 
     In the region of the joint bearing  16 , each clearing member  12  includes two parallel joint plates  26  spaced from one another in the direction of the joint axis  19 , thus forming a recess  27  in which the joint bearing  16  is received. Each joint plate  26  has a bore  21  in which the hinge pin  20  of the associated bearing  16  is anchored for connecting the clearing member  12  and the intermediate chain element  13  to one another. 
     As indicated also in FIG. 3, the intermediate chain element  13  further includes stabilizing webs  24 , positioned on both the upper and the lower side of the main portion  22  and situated centrally between the two joint bearings  16 . The stabilizing webs  24  extend perpendicularly to the longitudinal direction  15  of the clearing chain  4  and comprise stabilizing noses  25  extending out from the stabilizing web  24  at both sides thereof in the longitudinal direction  15 . As shown further in FIG. 4, each joint plate  26  of the clearing member  12  is provided with an indentation  28  in which the stabilizing nose  25  of the adjoining intermediate chain element  13  is received. 
     FIG. 5 shows a section through the clearing chain  4  positioned inside the guide track  11 . Sliding plates  32  are arranged inside the guide track  11  at the bottom and inner side wall thereof, having a slippery surface to facilitate the movement of the clearing chain  4 , or the clearing members  12  and intermediate chain elements  13 , making contact with the guide track  11 . 
     While the invention has been illustrated and described as embodied in a clearing chain for excavating bulk material, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.