This application claims priority to Canadian Application No. 2,762,705, filed on Dec. 22, 2011, which is hereby incorporated by reference in its entirety.
The present invention relates to the field of linear induction motor (LIM) rail installations, and more specifically, to a support system that comprises a plurality of movable support structures for supporting a LIM rail along a LIM rail installation.
Linear induction motors (LIM) for use in railway transit systems require a primary LIM component and a secondary LIM rail. The primary LIM component is generally carried by the railway vehicle, and the secondary LIM rail is generally provided along the railway track. In generally, the secondary LIM rail is a passive portion that interacts with the primary LIM component of the railway vehicle for generating induction currents that provide thrust between the primary LIM component and the secondary LIM rail. In this manner, the railway vehicle is propelled along the railway track over the secondary LIM rail.
The secondary LIM rail is formed of a plurality of secondary LIM rail portions that are positioned one after the other along the full length of a railway installation. The secondary LIM rail portions are located between the two running rails that support the LIM railway vehicle. Typically, the secondary LIM rail portions are constructed by assembling a welded back-iron with a support structure and an aluminum top-cap extrusion. The support structure generally extends along most of the length of the back-iron components and is adapted for securing the secondary LIM portion to a guideway. The process of fabricating this assembly requires specialized equipment and skilled labor in order to cut and machine the components and weld them together using specialized custom jigs. The final welded assembly of the secondary LIM rail portion is then transported to an installation site for being secured to a guideway.
These completed secondary LIM rail portions are heavy and the design cannot be adjusted (other than by cutting or drilling new mounting holes) after assembly. Therefore, for many LIM trackwork installations, custom designed modules are required in order to obtain a customized length or to accommodate special anchor stud spacing along an irregular section of trackwork. The mounting arrangements are also often difficult to access for tightening. Therefore, a deficiency with this traditional manner of fabricating secondary LIM rail portions is their inability to be field-adjustable to accommodate irregular sections of track work. This increases the complexity and cost of manufacturing and installing the secondary LIM rail, as customized secondary LIM rail portions need to be manufactured and transported.
In light of the above, it can be seen that there is a need in the industry for an improved manner of manufacturing, assembling, and installing the LIM secondary rail along a LIM trackwork installation, that alleviates, at least in part, the deficiencies of the prior art.
In accordance with a first broad aspect, the present invention provides a support system for a linear induction motor (LIM) rail portion. The support system comprises a plurality of support structures that are attachable at a variety of positions along a length of the LIM rail portion. Each support structure comprises a raised portion that defines a platform for receiving a back-iron component of the LIM rail portion and first and second fastening flanges that extend outwardly from respective upper sides of the raised portion. The first and second fastening flanges are attachable to a top cap extrusion of the LIM rail portion. Each support structure further comprises first and second supporting flanges that each extend outwardly from respective bottom sides of the raised portion for contacting a surface of the guideway to which the LIM rail portion is to be secured.
In accordance with a second broad aspect, the present invention provides a support structure for securing a linear induction motor (LIM) rail portion to a guideway. The support structure is attachable to the LIM rail portion at a variety of positions along a length of the LIM rail portion. The support structure comprises a raised portion defining a platform for supporting the LIM rail portion and a first flange portion and a second flange portion that each extend outwardly from respective bottom sides of the raised portion. A longitudinal axis of the support structure extends perpendicular to a longitudinal axis of the LIM rail portion.
In accordance with a third broad aspect, the present invention provides a support structure for securing a linear induction motor (LIM) rail portion to a guideway. The support structure is attachable to the LIM rail portion at a variety of positions along a length of the LIM rail portion. The support structure comprises a raised portion comprising a platform for supporting the LIM rail portion. The raised portion defines an internal passageway underneath the platform. The support structure further comprises a fastening arrangement for attaching the LIM rail portion to the support structure. The fastening arrangement is positioned outside of the internal passageway.
These and other aspects and features of the present invention will now become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention and the accompanying drawings. It will also be apparent that this invention could be applied to other technologies having single axle bogies including but not limited to rail vehicles, trolleys, wheeled carts without guide wheels, automotive applications, etc.
In the accompanying drawings:
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
Shown in
In accordance with the present invention, the secondary LIM rail portions 10 are secured to the guideway 16 of the rail installation via a support system that comprises a plurality of support structures 20. The support structures 20 secure the secondary LIM rail portions 10 to the guideway 16 between two running rails 12. As will be described in more detail below, in accordance with the present invention, the support structures 20 are movable in relation to the secondary LIM rail portion 10 such that they can be attached to the secondary LIM rail portion 10 in a variety of positions along its length. This allows the positioning of the support structures 20 in relation to the length of the secondary LIM rail portion 10 to be determined based on the nature of the trackwork at the installation location. This adjustability in the positioning of the support structures 20 allows increased on-site flexibility when securing the secondary LIM rail portion 10 to the guideway. The positioning of the support structures 20 can be adjusted to accommodate irregular sections of the trackwork and sections of the trackwork that have unusually spaced anchor holes
As shown in
The secondary LIM rail portion 10 comprises an aluminum top cap extrusion 14 and back-iron components (not shown in
Shown in
With reference to
Shown in
In accordance with a non-limiting example of implementation, the beam 36 that extends between the first side wall 32 and the second side wall 34 is positioned slightly below the upper edges of the first and second side walls 32, 34, such that the platform 24 provides a slight recess for receiving the back-iron component 18. As shown in
As shown in
The fastening mechanisms 46 are thus slid within the channels 40a, 40b of the top cap extrusion 14 to a desired location along the length of the top cap extrusion 14 where the support structures 20 should be attached. The fastening mechanisms 46 are then positioned through the apertures 42 within the first and second fastening flanges 38a, 38b of the support structure 20, for attaching the secondary LIM rail portion 10 to a support structure 20.
Even once the fastening mechanisms 46 have been placed through the apertures 42 in the first and second fastening flanges 38a, 38b, the support structure 20 can be slid along the length of the top cap extrusion 14. In this manner, the support structures 20 are movable and adjustable in relation to the top cap extrusion 14 such that they can be located in a variety of positions along the length of the top cap extrusion 14. Once a desired position has been achieved, the fastening mechanisms 26 can be secured to the first and second fastening flanges 38a, 38b, such as via the nuts shown in
Between the back-iron component 18 and the support structure 20 is a thin rubber/elastomer sheet which acts to dampen magnetic vibrations causing noise between the two mating surfaces. This thin rubber/elastomer sheet is substantially equal to width of the back-iron components 18. Since the surfaces are clamped, the rubber/elastomer sheet also prevents movement (horizontal slip) between the back iron components 18 and the platform 24 of the support structure, thus ensuring a stable configuration.
As shown in
As indicated above, when the LIM vehicle travels over the secondary LIM rail portion 10, relatively high magnetic attraction forces occur between the LIM primary and LIM secondary surfaces. These forces can create high deflection stresses on the fastening mechanisms 46 that clamp the iron bar components 18 to the platform 24 of the support structure. As such, in certain cases, additional mounting brackets can be applied to the bottom face of the back-iron components. These brackets would be bolted to the support structure to aid in the reduction of the stresses that may cause premature fatigue failure of the bolted joint.
Once the secondary LIM rail portion 10 has been attached to a plurality of support structures 20, the support structures 20 are then, in turn, secured to the guideway 16. This is done via the first and second supporting flanges 26a, 26b, as shown in
The ability of the support structures 20 to be movable in relation to secondary LIM rail portion 10 and attachable to the secondary LIM rail portion 10 in a variety of different locations along its length, allows flexibility in installing the secondary LIM rail portion 10 to the guideway 12. Instead of having customized LIM rail portion components, standard lengths of the top cap extrusion 14 and the back iron components 18 could be delivered to the track installation site. These standard lengths of the top cap extrusion 14 and the back iron components 18 can then be secured to irregularly shaped guideway sections or guideway sections that have uniquely positioned anchor holes, due to the adjustability and flexibility of the positioning of the support structures 20. Furthermore, in the case where the standard length of top cap extrusion and back-iron components 18 can't be used, these components can simply be cut to a desired length, which does not require skilled labor, have the ends painted, and then attached to the support structures 20 in the manner described above. As such, in cases where the top cap extrusion 14 and the back iron components 18 need to be cut to accommodate different trackwork installations, they can be cut with minimal effort and then the support structures 20 can be attached in appropriate locations along the newly cut length. Therefore, these movable support structures 20 help to avoid the need for customized secondary LIM rail portion 10 assemblies, due to their adjustability and flexibility in positioning relative to the length of the LIM rail portion 10.
Furthermore, by securing the support structures 20 to the secondary LIM rail portions 10 via fastening mechanisms 46, such as nuts and bolts, these support structures 20 permit easy change out of the back-iron components 18 when required. For example, when the LIM rail installation is being located in front of a mainline station, and a different thickness or design of back-iron component 18 is required for adjusting the thrust demand, it is not necessary to remove and replace the entire secondary LIM rail portion assembly. Instead the top can extrusion 14 can be removed, the different back-iron component 18 can be installed, and the top cap extrusion 14 can be re-attached to the support structures 20. This allows LIM rail performance to be adjusted locally with minimum effort, which saves both time and cost.
In addition, the support structures 20 according to the present invention help to prevent the wastage of materials since they are not permanently welded to the LIM rail portion. These support structures 20 can be removed from an old track installation and then re-used on a new track installation. Furthermore, these support structures 20 use less material and reduce the overall weight of the LIM rail portion assembly, when compared to traditional support structures that extend along almost the entire length of the secondary LIM rail portion 10.
In order to secure the support structures 20 to the guideway, fastening mechanisms 50 capable of engaging with the first and second supporting flanges 26a, 26b are used. The fastening mechanisms 50 can be any suitable fastening mechanism capable of securing the support structures 20 to the guideway 16, such as screws, bolts or rivets, among other possibilities. Such fastening mechanisms 50 would be known to a person of skill in the art, and as such will not be described in more detail herein. Depending on the material of the guideway 16, the fastening mechanisms 50 may be different. In the non-limiting embodiment shown, the fastening mechanisms 50 comprise bolts that are able to be threaded into anchor holes (not shown) within the guideway 16 for securing the support structures thereto.
As mentioned above, when installed to the guideway 16, the support structure 20 supports the secondary LIM rail 10 in an elevated position in relation to the guideway 16. Referring back to
In the example of a trackwork installation shown in
The support structures 20 according to the present invention are suitable for being installed on-site and as such are relatively small in size for facilitating handling and transportation. These support structures can be mass produced and then finished at a low-cost facility or on-site at a track installation. The support structures 20 can also be painted or nickel plated in order to avoid premature degradation or deterioration.
As shown in
According to a non-limiting example of implementation, each support structure 20 comprises a length l1 that is between 400-600 mm and a width w of between 125-170 mm. In a more specific non-limiting example of implementation, each support structure 20 has a length l1 of between 475-525 mm and a width w of between 145 mm to 160 mm. Furthermore, the length l2 of the raised portion 22 is between 325-375 mm. As such, the length l2 of the raised portion 22 is greater than the width w of the support structure 20. It should be appreciated that the above dimensions are provided strictly for the purposes of illustration, and should not be used to limit the scope of the present invention.
Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, variations and refinements are possible without departing from the spirit of the invention. Therefore, the scope of the invention should be limited only by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2 762 705 | Dec 2011 | CA | national |