Exemplary embodiments of the invention are in the field of railroad switching devices, namely, the equipment which is used to displace railroad switch points. More specifically, exemplary embodiments of the invention refer to a greaseless pivoting connector and/or clip.
A railroad switch point consists of tapered rail sections that are capable of being selectively displaced between two different lateral positions at a rail switch and then locked in the selected position in order to facilitate the desired routing of a train passing through the switch. The two switch points are typically displaced by rods extending from an assembly that is referred to herein as a “switch machine”. Inside the switch machine the rods are usually connected to a motive mechanism which provides reciprocating rectilinear motion controlled by a power unit which is usually placed to one side of the rails.
Such a device is described in Italian Patent No. IT1246656. The device described in that patent operates switch points which are independent, or disconnected, from each other, and it is not applicable to the problem of operating switch points of the interconnected type, i.e. of switch points connected to each other by transverse bars. Switch machines of the interconnected type are shown, for example, in U.S. Pat. Nos. 5,806,809, 6,149,106, and 6,691,958.
The switch machine combines the switch point movement and switch point locking functions into a single mechanism. This reduces mechanical complexity. The switch machine is also enclosed in a weather-proof housing. Also incorporated within the housing are sensors and other electrical control components. The housing and operating assembly are located beneath the switch points and the associated rails.
In such switch machines binding may occur, as described below, when the operating rod does not move along its intended longitudinal line of action. Instead it is subjected to lateral forces tending to cause it to bind at its attachment to the switch point and where the operating rod passes through the switch machine housing. A bearing and a seal are usually provided at the entry point into the housing to align the operating rod and to seal out water and other contaminants. The outer end of each operating rod connects to an associated switch point, and as the operating rod is moved in to and out of the switch machine housing, this substantially longitudinal movement of the operating rod is used to apply force to move the associated switch point laterally. The lateral movement of the switch point requires some change in the angle between the operating rod and the switch point because the switch point is actually pivoting about a pivot point at the other end of the switch point rail section. This change in angle can apply a lateral reactive force on the outer end of the operating rod. This, in turn, causes the inner end of the operating rod to apply substantial lateral force to the bearing and seal mechanism through which the operating rod enters the switch machine housing.
In addition, a more paramount problem that results is due to the thermal expansion of the tongue, or the part that is moved to set the track of the switch. The thermal expansion causes axial motion of the tongue wherein thermal expansion may be more than an inch depending on the temperature and length of the tongue. This lateral reactive force can cause premature failure of the seal and binding of the operating rod relative to the housing, which can cause the switch machine to lock up.
The switch assembly in the prior art requires grease at certain locations to insure smooth operation of the moving parts. Towards this end, regularly scheduled maintenance of the switch assembly must be accomplished to insure that all parts have sufficient grease.
Exemplary embodiments of the invention refer to a greaseless pivoting connector and/or clip. More specifically in a railroad switch for use with intersecting railroad rails and having two switch points interconnected by a switch machine between two switch point assemblies and connected thereto by an operating rod at each end of the switch machine, a system for a greaseless switch point assembly having a mounting clip and a pivot pin for connecting each operating rod to its associated switch point is disclosed. The system for the greaseless switch point assembly includes a bushing proximate a part of the pivot pin that fits within an opening in the mounting clip, and an insertion device extending into the opening proximate the bushing.
In another exemplary embodiment, in a railroad switch for use with intersecting railroad rails and having two switch points interconnected by a switch machine between two switch point assemblies and connected thereto by an operating rod at each end of the switch machine, a pivoting connector assembly with a greaseless switch assembly connecting each operating rod to its associated switch point is disclosed. The system for the greaseless switch assembly including a mounting clip having an opening therethrough. A pivot pin that rotatably traverses within the opening is also provided. A bushing fitting proximate a part of the pin that fits within the opening, and an insertion device extending into the opening proximate the bushing creating a surface proximate the opening are also provided. Wherein the bushing moves against the insertion device as the pivot pin is moved.
In yet another exemplary embodiment a system for a switch point assembly for a railroad track switch is disclosed. The system for the switch point assembly includes a mounting clip having an opening therethrough. A pivot pin proximate the opening and rotatably traversable within the opening is further disclosed. Also disclosed are a bushing proximate a part of the pivot pin that is proximate the opening, and an insertion device extending into the opening proximate the bushing.
A more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
With reference to the figures, exemplary embodiments of the invention will now be described. Exemplary embodiments of the invention are disclosed below specific to a pivoting connector. The scope of the exemplary embodiment of the invention is not limited to a pivoting connector within a switch machine. Specifically, exemplary embodiments of the invention may be implemented in association with other moving parts of a switch machine.
As shown in
Similarly, if the operating rod 5 were fixedly attached at a given point on the pin 108, pivoting of the switch point would pull the operating rod 5 to one side. These types of lateral or pivoting force on the operating rod 5 would cause it to bind in the bearing 102 and the seal 104. This binding would, at the very least, cause accelerated wear and premature failure of the bearing 102 and the seal 104. Further, this binding could actually lock up the entire switch machine, especially in the case where the two switch points are tied together. However, the connectors are also operative with and provide benefit for other between-the-rail switch machines in which the switch points are not tied together, other than via the operating rods. In the prior art, to assist in preventing wear and premature failure, grease is applied. Applying grease requires periodic inspection and application of grease to be performed.
As illustrated further in
While the invention has been described in what is presently considered to be a preferred embodiment, many variations and modifications will become apparent to those skilled in the art. Accordingly, it is intended that the invention not be limited to the specific illustrative embodiment but be interpreted within the full spirit and scope of the appended claims.
This application claims priority of Provisional Patent Application Ser. No. 60/748,241, filed on Dec. 7, 2005, which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2006/034139 | 8/31/2006 | WO | 00 | 5/21/2008 |
Number | Date | Country | |
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60748241 | Dec 2005 | US |