Abstract:
A vibrating device having a flywheel rotatably disposed within a housing assembly. The housing assembly includes one or more openings therethrough structured to allow an effective amount of air to pass between the housing assembly enclosed space and the atmosphere. By exchanging an effective amount of air between the enclosed space and the atmosphere, the temperature within the housing assembly remains below the breakdown point of a lubricant used to reduce friction created when the flywheel is in use.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a railroad track ballast tamping device and, more specifically, to a tamping device wherein a vibration motor has a housing with air passages. 
     2. Background Information 
     The gravel-like ballast underlying a railroad track must be compressed during the installation of new track or repairing old track. The typical means for compressing the railroad track ballast is to vibrate and/or tamp the ballast using a tamping machine. A tamping machine, which is mounted on a rail vehicle, typically consists of at least two pairs of tamping tools connected to a common vibrating device. Each tamping tool includes an elongated tamping head which is structured to be inserted into the ballast. An individual tamping head may include a fork-like tip with two, or more, prongs. A pair of tamping tools is further structured to move in a pincer-like manner. Typically in a pair of tamping tools, the individual tamping heads are in a spaced relation to each other so that the tamping heads may be inserted into the ballast on either side of a tie. The tamping heads are aligned so that the heads of an associated pair of tamping tools are disposed on one side of a rail. Further, a second pair of tamping tools is, typically, adjacent to the first pair but located on the other side of the rail. Thus, during a tamping operation, at the location of the intersection of a rail and tie, a tamping head will be disposed on each side of the tie and on each side of the rail. The tamping machine further, typically, includes two pairs of tamping tools disposed over each of the two rails in a railroad track. 
     During the tamping operation, the tamping heads are usually in a generally vertical orientation when inserted into the ballast. The tamping heads of an associated pair of tamping tools are then drawn together in a pincer-like motion so that the tamping heads are generally adjacent to a selected tie. The vibrating device is then actuated causing the tamping heads to vibrate and compress the ballast. The tamping heads are then removed from the ballast and the tamping machine is indexed, that is moved, to the next tie and the operation is repeated. 
     The vibrating device is coupled to each tamping tool. That is, each tamping tool may have a dedicated, or individual, vibrating device or a vibrating device may be mounted on a cross-member extending between the two or more tamping tools located on one side of a rail. The vibrating device, typically, includes an irregular flywheel that is rotated at high speed. The irregular shape of the flywheel causes the flywheel to vibrate during rotation. The vibration from the flywheel is mechanically transferred to the tamping heads via the tamping tool housing or frame assembly. That is, the flywheel typically rotates about a hub which has an axis of rotation that extends generally parallel to the ties and generally perpendicular to the rails. The hub engages a pair of bearings, one bearing on each side of the flywheel and is coupled to a motor. The flywheel and bearings are disposed within a closed housing assembly. The housing assembly is coupled, and preferably fixed, to the tamping tool frame assembly. The housing assembly is typically sealed. That is, the housing assembly is, essentially, airtight. However, there may be small passages that allow an insignificant amount of air to pass in and out of the housing assembly. 
     During a tamping operation the rotation of the flywheel creates friction with the bearings. Thus, a lubricant is typically applied to the bearings. The lubricant is structured for normal operations in open spaces and moderate environmental temperatures. While a sealed housing assembly generally provides acceptable performance, it has been noted that in warmer climates or in closed spaces, e.g. a tunnel, heat builds up within the closed housing assembly. When the heat buildup is not relieved, the temperatures within the housing assembly may pass the breakdown point of the lubricant. When the lubricant breaks down, the friction between the moving components cause enhanced wear and tear and, in very rare instances, may cause a complete failure of the vibrating device. Additionally, lubricant formulas are subject to change by various manufacturers. It has been observed that lubricants that have been acceptable in one formulation may be subject to heat related breakdown in a later formulation. Further, even when a lubricant does not fail due to an instance of excessive heat, the high operating temperatures cause the lubricants to wear out more rapidly. 
     SUMMARY OF THE INVENTION 
     The disclosed concept addresses the problem of lubricant break down in enclosed spaces and in high temperatures by providing an improved housing assembly for a tamping machine vibrating device. The vibrating device housing assembly includes one or more openings therethrough structured to allow an effective amount of air to pass between the housing assembly enclosed space and the atmosphere. By exchanging an effective amount of air between the enclosed space and the atmosphere, the temperature within the housing assembly remains below the breakdown point of the lubricant. 
     Preferably, the exchange of air is accomplished by the rotation of the vibrating device flywheel. That is, as the flywheel rotates, the flywheel causes a portion of the heated air within the housing assembly enclosed space to be expelled through one housing assembly opening. As the heated air is expelled, an equal volume of cool air is drawn into the housing assembly enclosed space via another opening or, if the openings have an extended length, through another portion of the same opening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic side view of a rail vehicle with a tamping machine. 
         FIG. 2  side view of a tamping machine vibration device. 
         FIG. 3  is a partial cross-sectional side view of a tamping machine vibration device. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As used herein, an “effective amount of air” means a volume of air sufficient to absorb a quantity of heat whereby the removal of the volume of air will prevent the ambient temperature at the original location of the volume of air from increasing beyond a selected temperature. 
     As used herein, “coupled” means a link between two or more elements, whether direct or indirect, so long as a link occurs. 
     As used herein, “directly coupled” means that two elements are directly in contact with each other. 
     As used herein, “fixedly coupled” or “fixed” means that two components are so coupled to move as one. 
     A tamping machine  10  structured to be coupled to a rail vehicle  5  is shown in  FIG. 1 . As is known, a railroad  1  includes a ballast  2  substrate upon which a plurality of ties  3  are disposed. One or more pairs of rails  4  are coupled to the ties  3 . A rail vehicle  5  includes a body  6  having a plurality wheels  7  coupled thereto. The wheels  7  are structured to travel over the railroad  1 . As shown, the rail vehicle  5  includes a number of other devices that are not recited in the claims below. The tamping machine  10  includes a frame assembly  12  and at least one tamping tool  14 . The frame assembly  12 , which typically includes a lifting device such as, but not limited to pneumatic or hydraulic pistons, is coupled to the rail vehicle  5  and is structured to raise and lower the at least one tamping tool  14  as described below. 
     The at least one tamping tool  14  includes a mounting plate  20 , an actuation device  22 , a vibrating device  24 , and at least one elongated tool head  26 . Typically, there are two tool heads  26 A,  26 B structured to move in a pincer-like fashion. The mounting plate  20  is pivotally coupled to the frame assembly  12 . The actuation device  22  and the vibrating device  24  are coupled to the mounting plate  20 . The axis of rotation of the mounting plate  20  extends generally laterally, that is, perpendicular to the rails  4 . The actuation device  22  is structured to pivot the at least one tool head  26  between a first position, wherein the at least one tool head  26  is spaced from a tie  3 , and a second position wherein the tool head  26  is adjacent to a tie  3 . The at least one tool head  26  has an upper end  30  and a lower end  32 . The at least one elongated tool head upper end  30  is coupled to the mounting plate  20 . The at least one elongated tool head lower end  32  is structured to be inserted into the ballast  2 . The at least one elongated tool head lower end  32  may be separated into two or more prongs. 
     The vibrating device  24  is structured to vibrate the at least one tool head  26 , as discussed below. The vibrating device  24  is coupled to, and preferably fixed to, the mounting plate  20 . As shown in  FIGS. 2 and 3 , the vibrating device  24  includes a housing assembly  40 , an irregular flywheel  42 , and a motor  44 . The housing assembly  40  includes a plurality of sidewalls  50  defining a substantially enclosed space  52 . The housing assembly  40  may define any shape, however, as shown, the housing assembly  40  typically is shaped as a short, wide cylinder with a generally horizontal axis and having a pair of mounting feet  54 . In this configuration, the housing assembly  40  includes a generally circular sidewall  56 , a first sidewall  58  and a second sidewall  60 . 
     At least one housing assembly sidewall  58 ,  60  has at least one opening  62  structured to allow an effective amount of air to pass therethrough. Preferably, both housing assembly sidewalls  58 ,  60  include a plurality of elongated, arc-shaped slots  64 . The arc-shaped slots  64  are preferably disposed in a circular pattern with the center of the circle generally corresponding to the axis of rotation of the irregular flywheel  42 , however, other patterns may be used as well. As discussed below, the irregular flywheel  42  has a diameter; the arc-shaped slots  64  are preferably disposed adjacent to the maximum diameter of the irregular flywheel  42 . The housing assembly sidewalls  58 ,  60  may also have axial access openings, however, such openings are covered by a side plate  66  or the motor  44 . The housing assembly  40  also include bearings  68  structured to support the irregular flywheel  42 . The circular sidewall  56  may include one or more drain holes  69  at or near the lowest point. 
     The irregular flywheel  42  is rotatably disposed in the enclosed space  52  and structured to rotate about an axis of rotation. The purpose of the irregular flywheel  42  is to produce a vibration when rotated, typically at a high speed. As such, various irregularities may be incorporated into the irregular flywheel  42  to produce the desired vibrating effect. In the preferred embodiment, the irregular flywheel  42  also causes air to move in and out of the enclosed space  52  via the at least one opening  62 . In the preferred embodiment, the irregular flywheel  42  has a body  70  having a disk portion  72  and a perimeter portion  74 . The disk portion  72  preferably has a constant thickness. The perimeter portion  74  has a thick section  76  and a thin section  78 . The thick section  76  extends over about 180 degrees of the circumference of the disk portion  72 . The thin section  78  extends over the other about 180 degrees of the circumference of the disk portion  72 . Due to the difference in the shape of the perimeter portion  74  of the irregular flywheel  42 , rotation of the irregular flywheel  42  creates a vibration. 
     The motor  44  has a housing  80  and a shaft  82 . The motor housing  80  is coupled, and preferably fixed, to the housing assembly  40 . The motor shaft  82  is coupled to the irregular flywheel  42  and structured to rotate the irregular flywheel  42  as indicated by the arrow “A.”. 
     When the vibrating device  24  is assembled, the irregular flywheel  42  is disposed within the enclosed space  52  and supported by the bearings  68 . The motor  44  is coupled to the irregular flywheel  42 . The side plate  66  and the motor  44  cover the axial access openings in the housing assembly sidewalls  58 ,  60 . Thus, except for the drain hole  69 , the only openings through the housing assembly sidewalls  58 ,  60  are the arc-shaped slots  64  disposed adjacent to the maximum diameter of the irregular flywheel  42 . Further, an air filter  100 , such as, but not limited to, a brush, may be disposed over the housing assembly at least one opening  62 . 
     In this configuration, the rotation of the irregular flywheel  42  causes an effective amount of air to pass through the arc-shaped slots  64 . As the irregular flywheel  42  rotates, the flywheel thick section  76  has a leading edge  77  and the flywheel thin section  78  has a leading edge  79 . As the irregular flywheel  42  rotates about the axis of rotation, heated air adjacent to the irregular flywheel thick section leading edge  77  and within the enclosed space  52  is expelled from the enclosed space  52  via an elongated slot  64 . Similarly, as the irregular flywheel  42  rotates about the axis of rotation, cooler air adjacent to the irregular flywheel thin section leading edge  79  and disposed outside of the enclosed space  52  is drawn into said enclosed space  52  via said elongated slot  64 . That is, the rotation of the irregular flywheel  42  generally increases the pressure of the air in the enclosed space  52  in front of the irregular flywheel thick section leading edge  77 . This increase in pressure causes the heated air in the enclosed space  52  to be vented. As the heated air is vented, cool air is drawn into the enclosed space  52  to replace the exhausted air. In this manner, the temperature within the vibrating device  24  may be controlled so that the temperature does not exceed a selected maximum. 
     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. For example, the irregular flywheel  42  may incorporate features to enhance the amount of air moved. That is, the irregular flywheel  42  may include one or more radial ridges (not shown) that act in a manner similar to fan blades and which increase the pressure in front of the irregular flywheel thick section leading edge  77  thereby increasing the amount of air exchanged. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.