A PANTOGRAPH CONTROL ASSEMBLY

Abstract: An assembly for maintaining the position of a pantograph (18) of a variable inclination train, the pantograph being tiltable relative to the train body. The assembly comprises a first rigid link (27) with one end attached to the bogie of the train and the other end attached to a first cam, a control shaft (32) with one end coupled to the first cam and the other end coupled to a second cam, a second rigid link (36) with one end attached to the second cam and the other end attached to the pantograph.

Description: TITLE A PANTOGRAPH CONTROL ASSEMBLY FIELD OF THE INVENTION This invention relates to a pantograph control assembly and particularly relates to an assembly for maintaining the position of a pantograph of a variable inclination train. BACKGROUND ART Variable inclination trains (also called tilt trains) have a train body which tilts relative to the train bogie. For electric trains, a pantograph is supported above the train body and contacts the overhead electric wires. If the pantograph is immoveable relative to the train body, tilting of the train body relative to the bogie will result in a pantograph also being tilted relative to the overhead electric wire. This limits the degree of tilting of the train body as it is essential that the pantograph and especially the uppermost contact bow maintains contact with the electric wire. There are advantages in lowering the centre of rotation of the train body in order to minimise lateral movement of the train body gravity centre and in order to improve riding comfort. However, lowering the centre of rotation results in a greater amount of lateral movement of the pantograph upon tilting of the train body, which further limits the amount of available tilt. An early attempt to maintain a good contact between the pantograph and the overhead electric wire had the pantograph supported by support pillars which extended around the outside or through the train body and which were bolted directly to the bogie. Thus, the pantograph was supported by the bogie and was not supported by the train body. Tilting of the train body therefore did not tilt the pantograph. This arrangement had many disadvantages. Firstly, the support pillars had to be large and strong to properly support the pantograph. Secondly, the support pillars being external of the train body limited the amount of tilting of the train body in order to prevent the train body from colliding with the support pillars. Internal support pillars resulted in an undesirable reduction in the amount of passenger space within the train body. Another attempt to overcome the above disadvantages was to provide a curved transverse rail supported to the roof of the train body on which the pantograph was attached and could slide. The pantograph was therefore tiltable relative to the train body. In one known arrangement, the pantograph was slid along the curved rail by cables, belts or wires which were attached to the train bogie and to the pantograph. This arrangement is described in European Patent Application No. 485,273. However, it has been found that the use of cables, belts or wires is not as reliable as it should be. Another known arrangement to allow the pantograph to tilt relative to the train body is described in European Patent Application No. 436,993. In this arrangement, the train body is tilted relative to the bogie by hydraulic cylinders. The pantograph is again attached to a curved rail and the curved rail is supported by the roof of the train body. Hydraulic cylinders on the roof of the train body push or pull the pantograph along the curved rail to keep the pantograph in contact with the overhead electric wire. This arrangement is relatively complex and requires the use of hydraulic fluid and therefore requires pumps, motors and high pressure hydraulic hose. Control units are also required to ensure that the hydraulic cylinders push or pull the pantograph along the curved rail at the required time. OBJECT OF THE INVENTION The present invention is directed to a assembly which will allow the pantograph to be moved relative to the train body upon tilting of the train body. The present invention does not require the use of hydraulics or cables. In one form the invention resides in an assembly for maintaining the position of a pantograph of a variable inclination train the pantograph being tiltable relative to the train body, the assembly comprising a first rigid link member having one end attached to the bogie of the train and another end attached to a first cam member the arrangement being such that tilting of the train body relative to the bogie results in the first rigid link member pushing or pulling the first cam member to cause the cam member to exhibit rotary motion, a control shaft extending between the first cam member and the pantograph and having a lower end operatively coupled to the first cam member such that the control member exhibits rotation upon rotation of the first cam member, a second cam member operatively associated with an upper portion of the control shaft to convert rotary movement of the control shaft into linear movement, a second rigid link member having one end attached to the second cam member and another end attached to the pantograph the arrangement being such that linear movement of the second link member causes tilting movement of the pantograph relative to the train body. The term "train" includes railway carriages, railway trains and locomotives which have a pantograph assembly and where the carriages tilt relative to the carriage bogie. The pantograph can be tiltable relative to the train body and this can be achieved by mounting the pantograph to a curved support rail. The curved support rail can be supported by the train body and typically is supported by the roof of the train body. The curved rail may not be continuous and indeed may comprise a number of curved rails. The pantograph may comprise an upper contact bow which contacts the overhead electric wire. The contact bow may be supported by a link assembly which maintains contact of the contact bow with the electric wire. The contact bow and link assembly may be supported by insulators which insulate the current carrying componentry from the train body. The insulators may be slidable along the curved support rail and this can be achieved by supporting the insulators on sliding blocks, rollers, sliding collars and the like. The train body may be tiltable relative to the train bogie by different means. One means can include a pendulum beam or tilt beam supported by the bogie and on which the train body is supported. The train body can be supported on the pendulum beam or tilt beam through shock absorbers which may include pneumatic or hydraulic cylinders, springs and the like. Another tilting arrangement is as described in European Patent Application No. 436,933 which uses a fixed bogie and hydraulic cylinders to tilt the train body relative to the fixed bogie. The first link member may comprise an elongate control rod. One end of the control rod may be pivotally attached to a portion of the non-tilting bogie, and the other end of the control rod may be pivotally attached to a tilting portion of the train. The first cam member may be attached to the tilting portion of the train such that tilting of the train body causes the first cam member to rotate due to its connection with the control rod. The control shaft may extend vertically through the train body and have a lower end attached to the first cam member and an upper end attached to the second cam member. The control shaft may include means to compensate for horizontal movement and vertical movement of the train body relative to the bogie. This may be achieved through splines and universal joints. The second cam member may be attached to the control shaft to be rotatable therewith. The second rigid link member may comprise a second elongate control rod having one end attached to the second cam member and the other end attached to the pantograph. Suitably, the other end of the control rod is attached relative to one or more of the insulators of the pantograph and results in moving the one or more insulators along the curved support rail when the control rod is rotated. BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will be described with reference to the following drawings in which Figure 1 is an end section view of a train in an upright position. Figure 2 is a view of the train of Figure 1 in a tilting position. Figure 3 is a side view of the tilting mechanism. Figure 4 is a plan view of the control rod and second cam member when the train body is in an upright position. Figure 5 shows the arrangement of Figure 4 when the train body is in a tilting position. Figure 6 is a plan view of the control rod and the first cam member. BEST MODE Referring to the drawings and initially to Figure 1, there is illustrated an assembly for maintaining the position of a pantograph of a variable inclination train (also called a tilt train) . Figure 1 shows a train comprising a train body 10 supported by a train bogie 11. Bogie 11 includes a bogie framework of generally known design and axles 12. Train body 10 is of usual design and comprises a floor 13, side walls 14 and a roof 15. Body 10 is attached to bogie 11 and cushioning means in the form of springs, pneumatic or hydraulic baffles and the like 16 are provided to cushion body 10 from the bogie 11. In the embodiment, train body 10 is attached to a tilt beam 17. Tilt beam 17 can tilt relative to bogie 11 to cause train body 10 to tilt train body 10 to tilt relative to bogie 11. It should be appreciated that other tilting mechanisms or assemblies may also be used. Above roof 15 is a pantograph 18. Pantograph 18 has an uppermost contact bow 19 which contacts the overhead electric wire to provide power to the drive motors of the train. Contact bow 19 is supported by a link arrangement 20 which functions to maintain contact bow 19 in contact with the overhead electric wire. Link arrangement 20 is attached to insulators 21, 22. Insulators 21, 22 are slidable along a pair of curved rails 23, 24. Curved rails 23, 24 have a centre of curvature coinciding with the centre of rotation (also called the tilt centre) of train body 10. It should be appreciated that while the embodiment describes a pair of curved rails 23, 24 it is also possible for a single curved rail to be present. Insulators 21, 22 are attached to their respective curved rails 23, 24 by a roller assembly 25 which is better illustrated in Figure 3. Roller assembly 25 comprises a roller or other form of rolling or slide mechanism 26 which can roll or slide along curved rail 24. Thus, insulators 21, 22 can move along their respective rails 23, 24. Pantograph 18 is tilted relative to train body 10 in such a manner to keep it immoveable or stationary relative to bogie 11. This is achieved by an assembly of link members and cam members as described below. A first rigid link member in the form of a control rod 27 has one end 28 pivotally connected to bogie 11 and has the other end 29 pivotally connected to a first cam member 30. Cam member 30 is attached relative to and moves with the tilting portion of the train. That is, cam member 30 can be attached either to the train body 10 or the beam 17. It can be seen that tilting of train body 10 between an upright position illustrated in Figure 1 and a tilting position illustrated in Figure 2 will result in control rod 27 pushing or pulling cam member 30 to cause the cam member to exhibit rotation about its axis 31. Attached to cam member 30 and about axis 31 is a control shaft 32 which is rotatable about its longitudinal axis. Control shaft 32 extends generally vertically through train body 10 and has a lower end attached to cam member 30 such that rotation of cam member 30 causes rotation of control shaft 32 about its longitudinal axis. Control shaft 32 can be attached through U-clamps or bearings 33 to a portion of the train body 10. The upper end 34 of control rod 32 is attached to a second cam member 35 such that second cam member 35 rotates with rotation of control shaft 32. Second cam member 35 is more or less identical to first cam member 30 and also has a lug portion to which a second link member in the form of a control rod 36 is attached. The upper arrangement is more clearly described with reference to Figures 4 and 5. Upper control rod 36 is attached to insulator 22 (or to the insulator support arrangement) . Thus, rotation of cam member 35 will cause linear movement of control rod 36 which in turn will push or pull insulator 22 along its curved rail 24. It can be seen that the assembly of the lower and upper control rods, the lower and upper cam members and the control shaft 32 results in the pantograph 18 being kept in position and in contact with the electric wire as the train body 10 tilts. The arrangement is mechanical and does not require the use of hydraulics, wires, cables, belts and the like. There is also no need for external supports as earlier proposals have given. The assembly may also include means to compensate for horizontal movement and vertical motion of train body 10 relative to bogie 11. This can be in the form of universal joints 37 and splines 38. The invention provides several advantages over previous known arrangements. Firstly, the assembly is compact and light-weight which eliminates narrow corridors between support columns. The assembly converts linear motion to rotary motion and back to linear motion to accurately control the position of the pantograph relative to the bogie. Standard parts can be utilised to reduce cost. Maintenance is reduced due to small angular movements of the parts. Universal joints and splined shaft transmits torque and compensates for all lateral, longitudinal and vertical movement of train body 10. The relative position of the pantograph is maintained in relation to the bogie at all times. It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit and scope of the invention.

Claims: CLAIMS 1. An assembly for maintaining the position of a pantograph of a variable inclination train the pantograph being tiltable relative to the train body, the assembly comprising a first rigid link member having one end attached to the bogie of the train and another end attached to a first cam member the arrangement being such that tilting of the train body relative to the bogie results in the first rigid link member pushing or pulling the first cam member to cause the cam member to exhibit rotary motion, a control shaft extending between the first cam member and the pantograph and having a lower end operatively coupled to the first cam member such that the control member exhibits rotation upon rotation of the first cam member, a second cam member operatively associated with an upper portion of the control shaft to convert rotary movement of the control shaft into linear movement, a second rigid link member having one end attached to the second cam member and another end attached to the pantograph the arrangement being such that linear movement of the second link member causes tilting movement of the pantograph relative to the train body. 2. The assembly of claim 1, wherein the pantograph is tiltable relative to the train body by mounting the pantograph to at least one curved support rail. 3. The assembly of claim 2, wherein the pantograph has an upper contact bow which contacts the overhead electric wire, the contact bow being supported by a link assembly which maintains contact of the contact bow with the electric wire. 4. The assembly of claim 3, wherein the contact bow and link assembly are supported by insulators which insulate the current carrying componentry from the train body. 5. The assembly of claim 4, wherein the insulators are slidable along the curved support rail. 6. The assembly of claim 1, wherein the first link member comprises an elongate control rod, one end of which is pivotally attached to a portion of the non- tilting bogie, and the other end of which is pivotally attached to a tilting portion of the train. 7. The assembly of claim 6, wherein the first cam member is attached to the tilting portion of the train such that tilting of the train body causes the first cam member to rotate due to its connection with the control rod. 8. The assembly of claim 7, wherein the control shaft extends through the train body and has a lower end attached to the first cam member and an upper end attached to the second cam member. 9. The assembly of claim 8, wherein the control shaft includes means to compensate for horizontal movement and vertical movement of the train body relative to the bogie. 10. The assembly of claim 8, wherein the second cam member is attached to the control shaft to be rotatable therewith. 11. The assembly of claim 10, wherein the second rigid link member comprises a second elongate control rod having one end attached to the second cam member and the other end attached to the pantograph. 12. The assembly of claim 11, wherein the other end of the control rod is attached relative to one or more of the insulators of the pantograph and results in moving the one or more insulators along the curved support rail when the control rod is rotated. 13. The assembly of claim 12, wherein the curved support rail has a centre of curvature coinciding with the centre of rotation

Inventors: JIRASEK JAROSLAV CONSTANTIN, JIRASEK, JAROSLAV, CONSTANTIN
Applicants: JIRASEK JAROSLAV CONSTANTIN, WALKERS LIMITED, JIRASEK, JAROSLAV, CONSTANTIN
Application year: 1996
Main classification: B60L5
IPC codes: B60L5, B61F5