The present application is based on and claims priority of Japanese patent application No. 2007-92504 filed on Mar. 30, 2007, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to transportation devices including railway vehicles such as railway cars or monorail cars and automobiles anticipated to receive shock by collision. The present invention specifically relates to transportation devices equipped with a shock absorbing device composed of a shock absorber formed of a material having superior shock absorption property for absorbing the shock occurring during collision.
2. Description of the Related Art
In a conventional railway car, a crushable zone for absorbing the shock received during collision is desirably disposed in the car body so as to ensure the safety of passengers and crew during collision. With respect thereto, Japanese Patent No. 3725043 (patent document 1) proposes providing shock absorbing devices at longitudinal end portions of the front car (including the rearmost car, the definition of which applies hereafter) and the intermediate cars, so as to receive the load applied to the ends of the car body during collision by absorbers disposed at endmost portions of the car body so as to relieve the shock.
According to the structure disclosed in patent document 1, the various levels of loads applied to the end portions of the car body are received by the shock absorbers disposed at endmost portions of the car body. Therefore, if the shock absorbers are designed to be easily collapsed by shock to absorb the shock effectively, the shock absorbers will receive load every time a minor collision occurs, according to which the shock absorbers must be replaced frequently, resulting in the hindrance of train operation and increase of costs. However, if the shock absorbers are designed to have a strong structure in order to overcome such drawback, the shock absorbing property may be deteriorated and the shock absorbers may not function effectively when a large collision occurs.
Therefore, the problem to be solved in a transportation device having a shock absorbing device is to realize an arrangement enabling the shock absorbing function of the shock absorbing device to be turned on and off according to the level of shock received during collision, so that the shock absorber will not exert its function in a minor collision.
The object of the present invention is to provide a transportation device with a shock absorbing device capable of turning the function of the shock absorber on and off according to the level of shock received during collision and to prevent frequent replacement of the shock absorber.
The object mentioned above can be achieved by a transportation device having a shock absorbing device for absorbing shock, wherein the shock absorbing device is turned off so that load is not transmitted to the shock absorber when a small load is applied, and the shock absorbing device is turned on so that load is transmitted to the shock absorber when a large load is applied to absorb the shock.
According to such arrangement, when the impact load is small, the load is not transmitted to the shock absorber, so that the load is not applied on the shock absorber and the shock absorber will not collapse. Therefore, compared to the prior art shock absorber that collapsed each time shock is applied, the costs and work related to replacing shock absorbers and to attach new absorbers can be cut down.
When the impact load is great, the load is applied on the shock absorber, by which the shock absorber is collapsed (function “on” state) to absorb shock.
An embodiment of the present invention will be described with reference to
As illustrated in
As illustrated in
The shock absorber 13 is a hollow extruded shape member having an octagonal cross-sectional shape formed of a material having superior shock absorbing property such as an A6063S-T5. The direction of operation of load with respect to the shock absorber 13 is right to left in
As illustrated in
The load operating unit 11 is the portion for receiving the impact load which is composed of a thick plate formed of aluminum alloy. The front side of the shock absorbing device 10A is the right side of
Further, a supporting unit 14 is arranged at a rear end portion of the shock absorber 13. The supporting unit 14 is fixed to a lower surface of the underframe 3 of the railway car body structure 5. The supporting unit 14 is a member for connecting the shock absorber 13 to the underframe 3 of the railway car body structure 5. The supporting unit 14 is not necessarily collapsed by the impact load.
The front end portion (right side in
The pin 15 is passed through a hole 19 formed to the load transmitting shaft 12 and a hole 20 formed to the supporting unit 14. The pin 15 has notched grooves 21 formed on the outer surface thereof at positions corresponding to the outer-side surface of the load transmitting shaft 12 and the inner-side surface of the supporting unit 14. The pin 15 is designed to break easily at the portions where notched grooves 21 are formed when impact load is applied on the pin 15.
Furthermore, the front end surface of the supporting unit 14 has a substantially equivalent shape as the outer shape of the closing plate 17, and a clearance is formed between members 14 and 17.
According to such arrangement, the function of the shock absorber 13 is turned on and off depending on the level of shock received during collision.
That is, when a small load is applied, the load applied on the load operating unit 11 is not applied on the shock absorber 13, since the rear end of the shock absorber 13 is free from the supporting unit 14. This state is referred to as “off”.
On the other hand, when a large load is applied on the load transmitting shaft 12 and the pin 15 from the load operating unit 11, the pin 15 breaks at portions where notched grooves 21 are formed, and the load transmitting shaft 12 is inserted to the inner side of the supporting unit 14. This state in which the pin 15 is broken is referred to as “on”.
When the pin 15 breaks, the closing plate 17 collides against the front end portion of the supporting unit 14, and the load is transmitted to the shock absorber 13. Thus, the inner cylinder 13a, the outer cylinder 13b and the plural plates 13c that connect the inner cylinder 13a and the outer cylinder 13b of the shock absorber 13 collide against the supporting unit 14, and the shock absorber 13 is collapsed by being crushed into a bellows with many small bucklings, by which the shock is absorbed effectively.
According to such structure, when a small collision occurs and even if the pin 15 deforms, there is a clearance formed between members 14 and 17 so that the shock absorber 13 will not deform, and there will be no need to replace the shock absorber 13 even if the pin 15 must be replaced. This arrangement enables to prevent the occurrence of lack of ability of the shock absorber 13 when a major collision occurs.
Further according to the present invention, even after the occurrence of a major collision, the shock absorbing device 10A can be reconstructed by removing the bolts and nuts 18, and replacing the shock absorber 13 including the closing plates 16 and 17 and the pin 15.
Furthermore, it is also possible to adopt an arrangement in which the supporting unit 14 also collapses when a large load is applied so as to absorb such large load.
Next, another preferred embodiment of the present invention will be described with reference to
The shock absorbing device according to the embodiment illustrated in
In
A load transmitting shaft 12 and the load transmitting member 11b are connected via a pin 15. The pin 15 has notched grooves 21 formed thereto which enable the pin to break easily by load.
Yet another embodiment of the present invention will be described with reference to
According to such structure, a shock absorber 13 which is to be collapsed is welded to a supporting unit 14, so that the maintenance property after the occurrence of a major collision by which the shock absorber 13 collapses is somewhat deteriorated, but effects equivalent to those of the embodiment of
Yet another embodiment of the present invention is described with reference to
Another embodiment of the present invention will be described with reference to
The front end (right side of
According to such arrangement, the external appearance is improved since the outer circumferences of the shock absorber 13 and the supporting unit 14 are covered with the load transmitting cylinder 22. Moreover, the present arrangement enables to reduce the shattering of small fragments of the shock absorber 13 collapsed by receiving a large load.
In the embodiment illustrated in
If the connection between the shock absorber 13 and the load operating unit 11 or the supporting unit 14 is realized via bolts and nuts instead of welding, it becomes possible to replace the shock absorber 13 easily.
Another embodiment of the present invention will be described with reference to
Furthermore, prior to fixing the supporting unit 14 to the lower surface of the underframe 3, bolts 27 are passed through a connecting member 25 welded to the front end of the supporting unit 14 and a connecting member 24 welded to the rear end of the load transmitting shaft 12, and the heads of bolts 27 are screw-engaged using a wrench through an opening 30. The nuts 28 of the bolts 27 are engaged using a wrench through the clearance formed between the supporting unit 14 and the closing plate 17.
According to this structure, when a collision applying a large load occurs, the bolts 27 break and the shock absorber 13 contacts the supporting unit 14, by which the impact is absorbed. According to this arrangement, it is necessary to replace only the shock absorber 13 including closing plates 16 and 17 and the bolts 27 and nuts 28, so costs can be reduced compared to when the pin 15, which is a processed product, must be replaced.
Moreover, since the tensile strength of the bolt 27 can be confirmed on a mill sheet obtained at the time of purchase, the quality of the shock absorbing device 10 can be stabilized.
Number | Date | Country | Kind |
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2007-092504 | Mar 2007 | JP | national |