ROLLOVER RESTRAINT SYSTEMS

FIELD OF INVENTION

The present invention relates to rollover protection systems in buses and coaches of various types. More specifically the invention relates to a mechanism which protects the residual space during roll over and thus aiding occupant safety.

PRIOR ART AND PROBLEM TO BE SOLVED

Occupant safety in vehicles is of prime importance in the present scenario across the world. Speed is one aspect that is most often associated with safety. With the advancement of road infrastructure, the vehicle speeds have increased dramatically. As the speed of the vehicle becomes higher there are greater chances for the vehicle to meet with accidents, which may vary in nature and magnitude. Accidents which are mostly associated with high speeds are of rollover in nature. Despite the advancement in suspensions which tend to stabilize the vehicle, accidents of rollover type still remain inevitable. Such rollover nature of accidents is more prone in long distance buses and coaches as the centre of gravity of the vehicle is too high and also the speeds with which they operate are mostly on the higher side.

The susceptible points are generally similar for any range of the bus. The joinery between roof and the side structure is something which first comes in contact with the ground followed by the waist rail area. Hence, conventionally the structure in these portions are strengthened by adding extra pillars, additional gussets, stiffeners etc. These ensure that the body structure does not deform beyond the residual space, i.e. the space which is constituted of the passengers and is supposed to be devoid of intrusions at all times. Although these additional members to the structure protect the residual space they make the bus heavier which in turn could have other cascading effects on the performance of the bus like fuel economy, acceleration, etc. Hence there is a need to design a system which is integral with the bus body structure which protects the residual space and yet does not add excess weight to the structure. This serves to be the basis of the present invention.

OBJECT OF INVENTION

The principle object of the invention is to provide a mechanism to protect the residual space for the passengers inside the saloon of a bus or coach in an event of rollover, thereby ensuring the safety of the passengers on board. Another object of the invention is to provide a mechanism integral with the structure of the bus which would assist in preserving the residual space. Yet another object of the invention is to provide a mechanism associated with the seats inside the bus/coach which can hold the seated passengers intact within the residual space of the bus in the event of a vehicle impact or rollover.

SUMMARY OF INVENTION

In an embodiment of the present invention, which achieves the objectives as quoted above a restraint system is installed on the roof structure of the bus. This restraint system is capable of pushing the side structures of the vehicle apart in an event of rollover and thereby protecting the residual space. The restraint system which gets functional only in the event of rollover is actuated by mechanisms as illustrated in later paragraphs. Another embodiment of the invention relates to restrain systems which are installed with the seats inside the saloon of the bus. Such restrain systems is capable of pushing the seats on the either side of the bus towards the centre, i.e. towards the gangway. Thus, the seated passengers are held intact in the centre portion of the bus, well within the limits of the intended residual space.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

The advantages and the features of the invention is illustrated in the accompanying drawings, wherein

FIG 1 shows the various constituent shell structure elements of a vehicle on which the restraint system of the present invention can be fitted;

FIG 2 depicts a typical shell structure without a rollover restraint system;

FIG 3 depicts a shell structure installed with a rollover restraint system actuated by a resilient member;

FIG 4 depicts a transverse member construction according to the invention;

FIG 5 depicts a shell structure installed with a rollover restraint system actuated by a hydraulic ram arrangement;

FIG 6 compares the sectional views of a typical shell structure with the ones installed with rollover restraint system;

FIG 7 illustrates a roll over situation on a shell structure with a resilient member as restraint mechanism;

FIG 8 illustrates a roll over situation on a shell structure with ram as restraint mechanism.

FIG 9 depicts the seat slider mechanism and its movement in an event of rollover; and

FIG 10 shows a flowchart which illustrating the operating sequence behind the seat slider mechanism.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein is the construction with which the subject invention is obtained. This invention is illustrated in the accompanying drawings, throughout which, like reference numerals indicate corresponding parts in the various figures. In the following description "roof structure" (R) refers to the entire upper portion constituting the roof of the vehicle shown in dotted lines in FIG 1. "Transverse member" (T) is a constituent member of the roof structure (R). "Ring structure" (RI) is constituted by the transverse member of roof, a side pillar and the transverse member of the floor. A typical shell structure of a vehicle incorporating the above elements is depicted in FIG 1.

FIG 2 depicts a typical shell structure of a vehicle, such as a bus or a coach, of the existing art having a waist rail (1) and a cant rail (2) on each side of the length of the vehicle adequately strengthened for roll over protection. The joinery (9) of the cant rail (2) and a transverse member (3) of the roof structure (R) is adequately strengthened with additional gussets for rollover protection. These ensure that the body structure does not deform beyond the residual space, i.e. the space which is usually constituted of the passengers and is supposed to be devoid of intrusions at all times. All these extra material add weight to the overall structure which cascades to affect the performance of the vehicle.

FIG 3 & 4 depict the shell structure of a bus according to the present invention. The transverse members (3) of the roof structure that connects the cant rails (2) on either side of the vehicle in the longitudinal direction, unlike in the typical arrangement, is split into at least three sections, with the centre section (4) being the weaker compared to the outer sections (5) on either side. The centre section (4) is connected (C) to the outer sections by welding or the like. The centre section (4) is accompanied by a precompressed member (6) adjacent to it. In one embodiment, the precompressed member is a resilient member such as a compressed spring (6). The resilient member (6) is held in place by two supports (7) integrated with the outer sections [5) on either side of the centre section (4) in the transverse member (3) of the roof structure. Preferably, the resilient member (6), in a compressed state, is inserted into the sleeves (16) provided on the supports (7). Depending on the length and the application of the vehicle the precompressed member can be positioned on all the transverse members (3) or on a select few which are more susceptible with regards to the intrusion in the residual space. For instance, in a rear engine city bus, the residual space in the rear is critical as the chance of the intrusion is more in that area.

In case of a coach the payload centre of gravity is almost uniform and so is the seating layout, thereby rendering the intrusion in the case of a coach to be same throughout. Therefore, in the former case few transverse members (3) in the front and all transverse members in the rear could have restraint systems and in the latter all or only critical few transverse members may have the precompressed members. In an alternate embodiment as shown in FIG 5, the precompressed member (6) installed with the centre section (4) of the transverse member (3) is a hydraulic ram (8). In a similar manner described with reference to FIG 3 the hydraulic ram (8) also is arranged so as to be held in place by two supports (7) via sleeves (16). FIG 6 compares the sectional views depicting the ring structure in all three cases. Figure 6(a) shows a ring structure with no restraint mechanism. Fig 6(b) shows a ring structure with three sections, the centre section (4) being installed with the rollover restraint system actuated by a resilient member (6). Fig 6(c) shows a ring structure with three sections, the centre section (4) being installed with the rollover restraint system actuated by a hydraulic ram (8). In an event of Roll, the first point that touches the ground is the joinery (9) of the roof and side structure at the cant rail portion (2). Eventually the structure starts to give in - thereby having a tendency to intrude in to the residual space (10). This is the case with a typical structure without a rollover restraint system.

FIG 7 illustrates an event of roll in a shell structure installed with a resilient member actuated restraint system. Unlike the earlier situation, the instant the joinery (9) touches the ground causing the impact, the centre portion (4) of the transverse member (3), being comparatively weaker and collapsible, fails. The impact of the side structure has some reaction forces at the pillar, which in turn would transfer the force to the transverse members of the ring structure. This impact would be sufficient enough to crumple/crush the centre portion (4) of the transverse members (3). Consequently the compressed spring (6) expands to gain its free form, thereby pushing apart the other sections of the transverse members (3) of the roof structure and the side members of the structure and eventually protecting the residual space (10) and the passengers inside. The support members that hold the springs remain intact.

The same roll over event with an alternate arrangement with hydraulic rams (8) is illustrated in FIG 8. The instant the joinery (9) touches the ground causing the impact, the centre portion (4) of the transverse member (3), being comparatively weaker and collapsible, fails. The impact of the side structure has some reaction forces at the pillar, which in turn would transfer the force to the transverse members of the ring structure. This impact would be sufficient enough to crumple/crush the centre portion (4) of the transverse members (3). Consequently the hydraulic ram (8) expands, thereby pushing apart the other sections of the transverse members (3) of the roof structure and the side members of the structure and eventually protecting the residual space (10) and the passengers inside. The support members that hold the hydraulic ram remain intact. The specifications of the resilient member and/or the hydraulic ram arrangement depends on the vehicle application and passenger capacities in the buses or coaches. Floor heights of the vehicles, terrain on which the vehicle moves as well as the strength required to open up the structures depends on these factors. Thus, the specifications will be chosen taking into consideration the above factors.

Another embodiment of the invention is illustrated in figure 9 and relates to the restraint system which are installed with the seats (11) inside the saloon of the bus. The seats (11) are mounted on horizontal telescopic rails (12) installed perpendicular to the side structure (13) of the bus and parallel to the bus floor (15). A seat mounting cantilever structure (14) extending angularly upward from the side wall (13) and joining at a suitable location on the rails (12) provides the required support for the seats (11) when in its home position or shifted position. These telescopic rails (12) are actuated pneumatically and are electronically controlled. The telescopic rails (12) include an actuator having a predefined stroke length just enough to clear the side structure during rollover. Although the seats illustrated in FIG 9 are cantilever type the concept can be applied to any type of seat mounting. In an event of rollover the telescopic rails (12) get actuated and pushes/slides the seats (11) along with the seated passengers towards the centre of the bus and thereby holding the passengers well within the residual space (10). The position of the seats prior and after rollover respectively are shown in FIG 9.

The logic behind the approach is illustrated by a flowchart in FIG 8. The rollover condition of the vehicle is sensed by a sensor, such as an accelerometer, fitted in the vehicle. If the rollover angle is lesser than the stability angle of the vehicle then the vehicle is said to be in a stable condition. If the rollover angle is greater than the stability angle of the vehicle then the vehicle is said to be in unstable condition and the rollover will happen. This signal from the accelerometer is communicated via the vehicle Controller Area Network (CAN) to the pneumatic actuating mechanism under the seat (11). The CAN system of the vehicle allows multiple devices installed in the vehicle to communicate through the same channel. After the sensor senses the rollover, instantly, the seat rows located closer to the road during rollover gets actuated and the seats move inward into the centre of the bus thereby holding the passengers well within the security of the residual space (10).

It can be envisaged to actuate sliding movement of all the seat rows on both sides of the bus to move inward irrespective of the direction in which the rollover occurs. Alternatively, the seats closer to the roads get actuated and move inward whereas the seats on the farther side slide on the telescopic rails due to gravity and/or the weight of the passengers. Insomuch as the present invention is subject to many variations, modifications and changes in detail, it is intended that the subject matter as discussed above and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

WE CLAIM

1. A shell structure of a vehicle comprising: cant rails on either sides of the vehicle-residual space created by the shell structure; transverse members connecting the cant rails at various points to form a roof structure, each or some of the transverse members comprising at least three sections, the centre section being collapsible upon impact; a rollover restraint mechanism installed with the centre section, said mechanism including a precompressed member capable of expanding and outwardly pushing the remaining sections of the transverse members when the centre section collapses in the event of a rollover of the vehicle..

2. The shell structure according to claim 1, wherein the precompressed member is a resilient member, such as a compressed spring.

3. The shell structure according to claim 1, wherein the precompressed member is a hydraulic ram.

4. The shell structure according to claim 1, wherein the precompressed member is held in place by supports integrated with the transverse members on either side of the centre section.

5. A seat unit for a passenger seating system in a passenger transport vehicle, wherein said seat unit is mounted on a telescopic rail installed perpendicular to a side structure of the passenger transport vehicle; said telescopic rail includes an actuator having a predefined stroke length, such that, in an event of rollover the telescopic rail gets actuated and slides the seat unit along with the seated passengers towards a residual space of the vehicle.

6. The seat unit according to claim 5, wherein an accelerometer senses the rollover condition of the vehicle.

7. The seat unit according to claim 6, wherein a rollover signal from the accelerometer is communicated via a vehicle Controller Area Network (CAN) to the actuator under the seat unit.

8. The seat unit according to claim 7, wherein seat units located closer to the road during rollover gets actuated.