Patent Application
20160305073
None
a. Field of Invention
This application pertains to a method of manufacturing a tie plate used for mounting railroad tracks on ties or other support means. The tie plate is formed with integral retainers for engaging the resilient clips used for holding the rails in place.
b. Description of the Prior Art
The present invention pertains to railroad rail fastener systems, and more particularly, to a method of manufacturing a tie plate. Railroads still constitute a major transportation means for moving goods as well as people. However in order for railroads to operate safely, reliably and inexpensively, it is important to keep their basic infrastructure sound to insure that the rails are available for service without any down time and accident free.
Inherently, rails and the fastening systems used to keep the rails in place play a crucial part of the railroad infrastructure and designing such fastening system requires a lot interdisciplinary effort between engineers, material science experts and heavy industrial manufacturers because the fastening system must be able to hold the rails in place, with very little tolerance in the position, movement and spacing of the rails as high speed passenger trains, or long and heavy freight trains pass over them.
It has been found that fastening systems consisting of a tie plate resting on a tie or other support and somewhat resilient clips securing each rail to tie plate are advantageous because they can be made reliably with the clips being able to hold on to the rails and resist tremendous linear and rotational forces on the rails. Of course, the retainers used to hold the clips on the plate are subject to the some of the same forces as the clips and must be able to transmit these forces to the tie plate. Until the present invention, these clips were made separately and were then attached to the tie plates by welding, press-fitting or other similar mechanical means. As a result, it was possible for these retainers to separate from the tie plate, in essence making the clips useless.
In one embodiment, the present invention presents a method of making plates by:
forming a metallic piece having a generally rectangular shape with bottom and top surface;
working said metallic piece to form a shaped piece having a generally flat body with a first and a second ends and a first and second protrusion extending from said first and second end, respectively, said first and second ends being disposed in parallel to each other, and said first and second protrusions being disposed on said top surface and in parallel top each other; and
drilling respective first and second bores from said first and second ends respectively through said body;
wherein said first and second bores extend only partially along a length of the respective protrusion; and
wherein said first and second bores are spaced and configured to receive the end of a retaining clip securing a rail to said tie plate.
As a result, a tie plate for securing a rail on a tie using first and second clips having respective clip end, is obtained including:
a relatively flat body having a first end, a second end and a top surface; and
a first and a second protrusion formed integrally with said body and extending in parallel on said top surface, said first protrusion extending from said first end and second protrusion extending from said second end, said first and second protrusions being parallel to each other, said first protrusion being formed with a first bore sized and shaped to receive one of said clip ends, and said second protrusion being formed with a second bore sized and shaped to receive the other of said clip ends;
said protrusions and the clips cooperating to restrain the rail on said top surface.
Holes are also provided in the plate for mounting the plate on a tie. Advantageously, a transversal hole is provided outwardly from each bore. This hole can be used to remove debris from the respective bore to insure that the respective clip end is seated properly within the bore.
The protrusions may extend from one end of the plate to the other, or may extend only partially from one end toward the opposite end.
Typically the support assembly 26 includes a tie plate 30 resting directly or indirectly on a tie 14 and secured by several spikes 32 or other conventional means. In the configuration shown in
The support assembly 26 has several disadvantages. it requires the bushings 34 to be mounted at the factory, thereby adding to the costs of the assembly, The bushings 34 add significant weight to the assembly In use, the bushings 34 may separate and fall off the plate 30 resulting in a potentially dangerous condition.
Plate 50 is cheaper to make then the plate 30. In addition, since the plate itself holds the ends of the clips, no additional clip retaining means such as bushings are required. Therefore a plate 50 is lighter and takes less to assembly. However, it has been found that during the process of shaping the plate in the configuration shown, the portions of the plate forming the humps 52, 54 can become thinner than the rest of the plate. The humps are subject to tremendous forces as a heavy train goes the plate, and after a time these humps 52, 54 can fracture. Moreover, because the cavities 60, 62 have typically a transversal shape that is larger than the cross-sectional diameters of the clips, the ends of clips 64, 66 are free to travel up and down with each wheel passing over the plate, causing excessive wear and tear of the plate and the clip ends.
Each protrusion is formed with a horizontal bore 88, 90 sized and shaped to receive an end 100 of a retainer clip, as discussed in more details below. Preferably, the length of each bore 88, 90 only needs to be same or a little longer then the length of clip end 100. Preferably, the depth of each bore 88, 90 is equal to or less than half the overall dimension L (
Preferably a small hole 94 is provided at the end of each bore 88, 90. One purpose of the hole 94 is to allow personnel in the field to clean out during installation any foreign matter and debris from the respective bore 88, 90 thereby insuring that the clip ends 100 can be inserted into the bores easily. The hole 94 may also be used to secure the plate 80 to insure that the plate is not stolen. The plate 80 further includes two lateral wings 96, 98 extending laterally outwardly from the bores 82, 84. These wings 96, 98 are formed with conventional apertures 99 for securing the tie plate 80 to conventional ties as described below.
The tie plate 80 is advantageous over the prior art plate of
The process for making a plurality of plates 80 is now described in conjunction with the flow chart of
In step 114 each strip 202 undergoes a shaping process (for example, rolling) to form a shaped strip 204 having a predetermined cross sectional profile, such as the one shown in
In step 116, the shaped strip 204 is partitioned transversally along, lines 206 into several individual plates 208 using shearing or other conventional techniques. As can be seen in
In step 118 bore 88 is made from one end of each plate.
In step 120 a second bore 90 is drilled from the other end of the plate.
In step 122 the hales 99 are formed in the plate 208. Of course steps 118, 120, 122 can be interchanged, or performed simultaneously.
The end result is a plurality of plates 80 illustrated in
Because a significant portion of each protrusion 88, 90 does not include a bore, and because the bore has a diameter just large enough to receive the clip ends, the protrusions and the plate are much stronger and can withstand large distorting forces much better.
In an alternate embodiment, the protrusions 88, 90 extend only partially across the plate. Of course, in this case, each protrusion starts from a respective edge of the plate.
Numerous modifications may be made to this invention without departing from its scope as defined in the appended claims.
