Background Art The existing train has no safety apparatus against the problem mentioned above. And the safety equipment that is installed at the platform is set up at a large cost. There exist some proposals and patents related to the said safety apparatus installed at the train, but in all those ideas safety apparatus is driven by an independent power, and so needs large costs in installing it at the train.

Disclosure of the Invention Technical Task The safety apparatus of the present invention uses no independent power and controller, and so can be set up at the train gate at a low cost.

Technical solution In the present invention, the safety apparatus is comprised of a stepping board and a power linker. The said stepping board is installed at the bottom side of the train gate and can be rotated by the said power linker about an axis that is parallel to the train's running direction. The said power linker is installed at a position near the moving path of the sliding door and is comprised of a door-linker coupling means (power input part) and a motion transforming means (motion transforming part). And an attachment that can interact suitably with the said power input part is attached on the sliding door. During the sliding door moves (and consequently the said attachment moves), the said attachment can interact with the said power input part of the said power linker at some position. During the interaction between the said attachment and the said power input part happens, the said power linker rotates the said stepping board. As the result of those mechanism, the said stepping board is driven by the sliding door and there is no need of independent power and controller.

Advantageous Point The safety apparatus of the present invention needs no independent power and controller, so it can be installed at a low cost. And moreover it provides more safe way because there can be no malfunction of the system.

Brief Description of the Drawings Figure 1 is a drawing that shows the whole configuration of the system of the present invention, Figure 2 is a drawing that shows the relationships between the major parts of the system, Figure 3 is the upper view of the power linker of the Ist form of implementation, Figure 4 is the side view of the power linker of fig. 3 viewed from +y direction, Figure 5 is a drawing that shows the movement of the power input part of the power linker of fig. 3, Figure 6 is a drawing that shows a form of junction using spring between the power input part-the arm and the first component of the motion transforming part of the power linker of fig. 3, Figure 7 is an assembling drawing that shows detail relationships between all parts of fig. 6, Figure 8 is a drawing that shows a part of the power linker of fig. 3 which uses a spring for weight balance, Figure 9 is a drawing that shows relationship between the attachment and the power input part of 2nd form of implementation of the power linker, Figure 10 is a drawing that shows relationship between the attachment and the power input part of 3rd form of implementation of the power linker, Figure 11 is a drawing that shows relationship between the attachment and the power input part of 4th form of implementation of the power linker.

Best Form of Implementation The whole configuration of the safety apparatus of the present invention is shown in Fig. 1 and Fig. 2. The said stepping board (4) is installed at the bottom side of the train gate and can be rotated by the said power linker (3) about an axis (9) that is parallel to the train's (1) running direction (y direction). The said power linker (3) is installed at a position near the moving path of the sliding door (2) and is comprised of a door-linker coupling means (power input part, 7) and a motion transforming means (motion transforming part). And an attachment (6) that can interact suitably with the said power input part (7) is attached on the sliding door (2). During the sliding door (2) moves (and consequently the said attachment moves), the said attachment (6) can interact with the said power input part (7) of the said power linker (3) at some position. During the interaction between the said attachment (6) and the said power input part (7) happens, the said power input part (7) moves, and the motion transforming part of the said power linker (3) transforms the motion of the said power input part (7) into suitable rotational motion of the output axis (8) about y direction so that the output axis (8) of the power linker (3) that is joined to the said stepping board (4) can rotate the said stepping board (4) suitably. As the result of the mechanism described above, the said power linker (3) can rotate the said stepping board (4) during the interaction between the said attachment (6) and the said power input part (7) happens. And so the said stepping board (4) can be positioned at a state of the two, 4-1 and 4-2. The state 4-1 means that the said stepping board (4) is close to the door (2), and the state 4-2 means that it is extended to the platform (5) so as to cover the gap between the train and the platform. (For the convenience of the following descriptions, the coordinate system used in Fig. 1 will be used consistently.) In the 1st form of implementation of the said power linker (3) shown in the Fig. 3 and Fig. 4, z shaped pocket (6-1) is used as the said attachment (6), and an arm (7-1) that can be rotated about z direction is used as the said power input part (7). And a roller (10) that can be rotated freely about z direction is installed at the end of the said arm (7-1). Figure 5 shows the relationship between the said pocket (6-1) and the said arm (7-1). In the figure, the drawings of dashed lines describe completely closed state of the sliding door (2), and the drawings of solid lines describe somewhat unclosed/open state. When the sliding door (2) begins to move from closed state to open, the said pocket (6-1) moves to right pushing the roller (10) side end of the said arm (7-1). And when the said arm (7-1) is rotated clockwise through the angle (a), the interaction between the said pocket (6-1) and the said arm (7-1) ends because the roller (10) side end of the said arm (7-1) gets out of the said pocket (6-1). As the door (2) continues to move, the said roller (10) revolves, contacting the surface of the door (2). During the sliding door (2) moves from open state to closed one, and from when the right end of the said pocket (6-1) reaches to the position of the said roller (10), the right end of the said pocket (6-1) begins to push the roller side end of the said arm (7-1) to the left, and the said arm (6-1) is rotated counterclockwise through the angle (a), and is returned to the home position (dashed drawing). The rotational motion about z direction of the said arm (7-1) is transformed to rotation about y direction, and the rotation angle (a) is also adjusted to 90 degrees through the motion transforming part of the said power linker (3). In the figure 3, the said motion transforming part is comprised of a pair of acceleration gear (11,12) and a pair of helical gear or a pair of bevel gear (13,14). The first plane gear (11) is joined coaxially with the said arm (7-1), and the second plane gear (12) is joined coaxially with the first helical gear (13). So, as the said arm (7-1) is rotated through the angle (a) about y direction, the output axis (8) can be rotated through 90 degrees about y direction. The motion transforming part can be comprised of only a pair of bevel gear, and in that case, rotation angle adjustment can be carried by determining appropriately the gear ratio between the two bevel gears.

When the said stepping board (4) is at one state of the two (4-1, 4-2), it is necessary to push it to the desired direction so as to fix it to the door (2) or to the platform (5). For the sake of fixation of the board, it is needed to use some springs at a suitable point out of several junctions between the components of the said power linker (3), and is needed to adjust rotation angle of the output axis (8) to be above 90 degrees.

In the form of the implementation of the figure 3, one example of using springs for fixing the board is shown in figure 6 and 7. In figure 6 and 7, two torsion springs (15,16) are used as a connecter between the said arm (7-1) and the first plane gear (11). One end of each torsion spring is fixed to the said plane gear (11) by being inserted to the hole (17) formed on the plane gear, and the other end is positioned by side of the said arm (7-1) so as to be twisted by rotation of the arm. And two bosses (18) formed on the plane gear restrict the twisting ranges of the two torsion springs so as not to interact between them. In that construction, as the said arm (7-1) is rotated counterclockwise/clockwise, the first/second torsion spring (15/16) rotates the plane gear (ll) counterclockwise/clockwise. Needless to say, adjusting rotation angle of the output axis (8) to be above 90 degrees is carried by determining the ratio between gears. Springs for fixing the board can be used at any junction point in the power linker (3).

For the sake of smooth rotation of the stepping board (4), it is necessary to attach a weight to the rotation axis that can balance against the weight of the board (4), but that could be difficult because of space problem.

As a solution of the problem, another spring for weight balancing can be used at a suitable point out of several components of the said power linker (3). In an example shown in figure 8, a tension spring (20) is installed on the plane gear (ll) so that restoring force of the spring (20) acts upon the gear (ll) as rotating it counterclockwise and consequently acts upon the said stepping board (4) as rotating it upwards. And as the result, the restoring force of the spring (20) acts as a weight balance against the weight of the board (4). The spring for weight balancing can be installed on any component in the said power linker (3), and type of the spring can be tension, compression, or torsion.

Other Forms of Implementation The pair of the attachment (6) and the power input part (7) may have several variations. The followings are some of the variations.

In the example shown in figure 9, a rack (6-2) extended to y direction is used as the attachment (6), and a pinion (7-2) that can be rotated about z direction is used as the power input part (7). In the example, during the rack (6-2) and the pinion (7-2) interact in the middle of sliding of the door (2), the said stepping board (4) is driven. And in the example, the said motion transforming part also comprises rotational direction transforming components.

In the example shown in figure 10, a rack (6-3) that has inclined teeth of 45 degree and is extended to y direction is used as the attachment (6), and a pinion (7-3) that has helical teeth and can be rotated about y axis is used as the power input part (7). In the example, there is no need of rotational direction transforming function in the said motion transforming part.

In the example shown in figure 11, a furrow (6-4) that comprises an inclined portion and is extended on the whole surface of the door (2) to y direction is used as the attachment (6), and a pair of rack (22) that can be moved to +/-z direction and pinion (23) that can be rotated about y direction is used as the power input part (7). The said rack (22) has a boss on the door side that is inserted into the said furrow (6-4). As the said boss on the rack (22) passes through the inclined portion of the said furrow (6-4), the said rack (22) is moved to +/-z direction, and consequently the said pinion (23) is rotated. A fixed guide (21) that has a guide hole extended to z direction is used to guide the said rack (22) to z directional movement. In the example, there is no need of rotational direction transforming function in the said motion transforming part.