Pantograph unmovable with respect to bogie frame

Abstract: A pantograph unmovable with respect to bogie frame for a rolling stock with a tilt system is provided. The pantograph unmovable with respect to bogie frame (11) is characterized by having a movable pantograph support (8) for the rolling stock so that the pantograph (11) is movable in a plane perpendicular to the longitudinal axis of the rolling stock. By the pantograph unmovable with respect to bogie frame, collecting strips keep contact with contact wire (20) even when the car body (1) is tilted.

Description: The present invention relates to pantographs of rolling stocks, and more precisely relates to pantographs supported unmovably with respect to the bogie frame, in other words, supported movable with respect to the car body while keeping the relative position of the pantographs unchanged with respect to the bogie frame. Movable pantographs are advantageous especially in rolling stocks having systems to naturally or actively tilt the car bodies of the train. Various schemes have been proposed to tilt the car bodies of a rolling stock as the train passes on a curved track at high speed. When the car bodies are tilted inward, the passengers feel less steady horizontal acceleration and the riding comfort is improved. Figures 4 shows a rolling stock having a system for actively tilting a car body 1. In Figure 4, the car body 1 is supported by air springs 13 which are supported by a pendulum beam 14. The pendulum beam 14 is supported by a pair of rollers 15 so as to permit swing motion of the pendulum beam 14 in a direction transverse to the longitudinal axis of the car body 1. The rollers 15 are supported on a bogie frame 2 which is on axles 21.In case of an active tilt system, an actuator 16 is provided on the bogie frame 2; and tilt angle of the pendulum beam 14, and therefore the car body 1, is controlled by virtue of the actuator 16. When the actuator 16 is activated, the car body 1 tilts along the dotted line shown in Figure 4, for example, by virtue of the swinging motion of the pendulum beam 14. The center of rotation 12 is somewhere on the vertical central axis of symmetry of the car body 1. A pantograph 11 on top of the car body 1 is rotated about the center of rotation 12 as the pendulum beam 14 swings, as shown in Figure 4. When the car body 1 is tilted the relative displacement between the pan-bow 11a of the pantograph and the contact wire 20 increases as the tilting angle of the car body 1 increases. The tilting angle of the car body 1 is therefore limited since the displacement of the pan-bow 11a relative to the contact wire 20 must be less than the length of collecting strips 11b; if the relative displacement exceeds the collecting strips length, the collecting strips 11b of the pan-bow 11a and the contact wire 20 will lose electrical contact. Therefore, since the degree of tilting angle of the car body is limited by the necessity of maintaining contact between the collecting strips 11b of the pan-bow 11a and the contact wire 20, and on the other hand, since the degree of tilting angle of the car body 1 necessary for riding comfort may be large, the improvement in the riding comfort in such a car body 1 is limited. In addition to above, there is a demand to lower the center of rotation 12 of the car body 1 in order to minimize a lateral movement of the car body gravity center and in order to improve the riding comfort. However, lowering the center of rotation 12 increases the relative displacement between the collecting strip 11b of the pan-bow 11a and the contact wire 20. A solution for the problem described above, according to a conventional technology, is to support the pantograph 11 from the bogie frame 2, independently of the car body 1, by a support frame 8 and a bolster 14′, as shown in Figures 5 and 6. The bolster 14′ is fixedly supported by the bogie frame 2. Since in this case the bolster 14′ does not swing, the relative displacement between the collecting strips 11b and the contact wire 20 will be negligibly small as the car body 1 tilts by virtue of the system for intentionally tilting. However, a major problem with this solution is that the support frame 8 obstacles the passengers space in the car body 1 since the support frame 8 protrudes into the car body 1. Another problem is that the relative displacement between the support frame 8 and the car body 1 requires a dead space between the support frame 8 and the car body 1. Further problem is that a massive frame 8 is necessary. Another prior art pantograph unmovable with respect to a bogie frame for a rolling stock (US-A-1 828 945) is supported by the rolling stock so as to be movable in a plane perpendicular to the axis of motion of the rolling stock, so that the collecting strips of the pantograph can keep contact with a contact wire even when the car body is tilted. It is an object of the present invention to provide a pantograph for a rolling stock, which permits a large tilting angle of the car body without limiting the passenger space. For that purpose there is provided a pantograph for a rolling stock according to claim 1. Other features of the present invention are defined in the dependent claims and described in the following description of preferred embodiments. Figure 1 is a sectional view of a pantograph according to the present invention provided to a car body having a system for tilting the car body. Figure 2 is a plan view of a pantograph unmovable with respect to the bogie frame according to the present invention. Figure 3 is a perspective view of a pantograph according to the present invention. Figure 4 is a sectional view showing a car body having a system for tilting the car body, and a pantograph fixed on the car body. Figure 5 is a sectional view showing a pantograph supported from the bogie frame so as to reduce the relative displacement between the pantograph and the contact wire. Figure 6 is a sectional view along the longitudinal axis of the train, showing the pantograph and the support mechanism as shown in Figure 5. With reference to Figures 1, 2 and 3, a preferred embodiment of the present invention will be described in detail. In Figure 1 and 3, a pantograph 11 is provided on a pantograph support 8. Each pantograph support frame 8 has a sliding mechanism which moves the pantograph support frame 8 in a plane perpendicular to the axis of motion of the rolling stock; this movable mechanism includes a slide bearing guide 10 provided on the roof of car body 1, and a slide bearing block 9 which smoothly moves along the sliding guide 10. The shape of the sliding guide 10 is not straight; instead, it is arc-shaped and has a radius R (shown in Figure 1) which coincides with the distance from the center of rotation of the car body 1, so that the relative displacement between an collecting strips 11b and an contact wire 20 is smaller. A drum 5 winding two cables 3 is provided on the underside of the pantograph support frame 8, and is supported by a drum support bearing 7. The two cables 3 are provided through the car body 1, from a bogie frame 2 which is not involved in tilting the car body 1. It is possible to use chains or belts in place of the cables 3. The pulleys 4 or the guide casing are provided along the car body 1 so as to guide the cables 3. As shown in Figure 1, the pantograph support frame 8 can smoothly move in the direction perpendicular to the direction of motion of the rolling stock by means of the sliding guide 10 and the slide bearing block 9. One end of a tension spring 6 is fixed on the pantograph support frame 8, the other end is fixed to the winding drum 5, so as to tense the cables 3. The apparatus for tilting the car body is omitted in Figures 1, 2 and 3. In the following, the operation of the pantograph is described. As shown in Figure 1, when the car body 1 is tilted by virtue of the apparatus for tilting a car body, the pantograph 11 remains unmovable with respect to the bogie frame 2 while the car body is rotated around the center of rotation 12. It is because the cables 3 keep the location of the pantograph support frame 8 unchanged with respect to the bogie frame 2. The tension spring 6 provides approximately constant tension to the cables 3 while permitting a temporary release and traction of the cables 3 in response to fluctuating external forces exerted on the cables 3, so as to prevent an excessive force from being applied to the cables 3. When the tilting car body 1 returns to an upright position, the pantograph support frame 8 is pulled in the direction opposite to the side of tilting, by means of the cable 3 on the opposite side of the car body 1. The pantograph support apparatus for a rolling stock of the present invention as thus described provides the following advantages: The pantograph 11 is maintained in a position right above the axle. Therefore, the displacement between the pantograph and the contact wire is minimized. As a result, a car body can be tilted up to an necessary angle in order to improve the riding comfort. In addition thereto, air springs can be provided above the tilt mechanism, and the riding comfort is further improved thereby. The pantograph support apparatus according to the present invention does not obstacle the passenger space. Since the mechanism of the pantograph support apparatus, consists of a slideable pantograph support and cables connecting the pantographs and the bogie frame, is mechanically very simple and light in weight, the mechanism of the pantograph support apparatus is less likely to fail in comparison to the pantograph support apparatuses of the prior art, and the pantograph support apparatus is therefore highly reliable.

Claims: A pantograph unmovable with respect to bogie frame for a rolling stock, comprising: a pantograph unit (11) supported by a rolling stock and movable with respect to said rolling stock in a plane perpendicular to the axis of motion of the rolling stock; moving means for moving the pantograph unit (11) relative to a car body (1) comprising at least two elongated connecting means (3) extending on both sides of the car body (1), each elongated connecting means (3) having one end fixed on the bogie frame; and winding means (5) for winding the elongated connecting means (3), provided at the pantograph support frame (8), said winding means (5) having each of the other ends of the elongated connecting means (3) fixed thereon, and said winding means (5) being rotatable so as to adjust the elongated connecting means (3) in reciprocating fashion; characterized in that a tension means (6) is provided at said winding means (5) to provide tension for turning the winding means (5). A pantograph according to claim 1, wherein said tension means (6) is a spring having one end fixed to the pantograph support frame (8) and the other end fixed to the winding means (5). A pantograph according to claim 1, wherein said tension means (6) is an elastic material having one end fixed to the pantograph support frame (8) and the other end fixed to the winding means (5). A pantograph according to any one of claims 1 through 3, wherein said moving means comprise a guide means for guiding movement of the pantograph support frame (8) so as to move the pantograph support frame (8) perpendicularly to the longitudinal axis of motion of the rolling stock. A pantograph according to claim 4 , wherein the guide means comprise slide bearing channels (10) which are provided on a roof of the body (1), and slide bearing blocks (9) which are carried by the pantograph support frame (8) for sliding along each of the slide bearing guide channels (10). A pantograph according to claim 5, wherein the longitudinal cross sections of the slide bearing guide channels (10) are partial arcs of a circle in a plane perpendicular to the longitudinal axis of the rolling stock and having a center coincident with the center of rotation (12) of the tilting car body (1). A pantograph according to claim 1 , wherein the elongated connecting means are cables. A pantograph according to claim 1 , wherein the elongated connecting means are chains. A pantograph according to claim 1, wherein the moving means comprise guide means (4) to guide the elongated connecting means. A pantograph according to claim 9, wherein the guide means (4) are pulleys or a guide casing. A pantograph according to claim 9, wherein the guide means (4) are gears.

Inventors: ENOMOTO MAMORU, FUJITA TOYOSHI, OKAMOTO ISAO, SHIMOMURA TAKAYUKI, ENOMOTO, MAMORU, FUJITA, TOYOSHI, OKAMOTO, ISAO, SHIMOMURA, TAKAYUKI
Applicants: RAILWAY TECHNICAL RES INST, RAILWAY TECHNICAL RESEARCH INSTITUTE
Application year: 1991
Main classification: B60L5
IPC codes: B60L5