Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

A MULTI-SEATER FULL BENCH FOR A VEHICLE;

MAHINDRA & MAHINDRA LIMITED, A COMPANY REGISTERED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING ADDRESS AT MAHINDRA RESEARCH VALLEY (MRV), MAHINDRA WORLD CITY, PLOT NO.41/1, ANJUR P.O., CHENGALPATTU, KANCHIPURAM DISTRICT, TAMILNADU – 603004, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
 
TECHNICAL FIELD
[1] The present invention relates to a multi-seater full bench for a vehicle.
BACKGROUND
[2] Bench seats for vehicles to accommodate passengers rearward to a driver’s seat are mainly available in two configurations, namely full bench-type configuration, and split-type configuration (such as 60/40 seat, 40/20/40 seat, etc.). A full bench type seat has a continuous backrest frame portion integral to a base frame portion, whereas a split-type seat has discontinuous frame portions. The full bench seat offers multiple advantages over split seats by offering accessibility through a tail door for side facing seats to increase the seating capacity, besides a big luggage cabin. Further, the full bench seat is easier to manufacture and has a simpler structure compared to split-type seats.
[3] In recent times, it has been a priority of automotive industry standards to improve passenger safety. As per the prevailing automotive industry standards, a large number of vehicles today in use offer an emergency locking retractor (ELR) and a three-point seat belt for both the left and right outboard occupants of seat row(s) rearward to the driver’s seat. A pre-tensioner in a three-point seat belt enables the belt to retract during sudden deceleration, thus enabling a snug fit, which encompasses better safety. The impact force thereby gets distributed over an upper effective anchorage point in addition to two lower effective anchorage points.
[4] There has been identified a need to provide such a three-point seat belt to a passenger seated in the rear middle seat as well, since certain existing systems having lap belts (being two-point seat belts) for the rear middle seat passenger may not be sufficient to retain the passenger to the middle seat, leading to injury or even death. The use of two-point seat belt had been earlier considered as a passive safety in the automotive industry for an occupant of the middle seat. Heading towards an increase in the safety of the passengers, mandating the use of a three-point seat belt for all the rear row seats is considered.
[5] However, in case of full bench seats, it is particularly challenging to package a three-point seat belt for the rear middle seat, owing to loading conditions on the seat framework during crash or sudden braking. In the case of a split-type seat, the deceleration load gets divided and separately limited to the split seat structures and the corresponding mountings. A full bench seat or a 100P seat has a continuous structure and generally lesser weight compared to a split-type seat. When such a full bench seat is subjected to deceleration loading, it is observed that the upper cross tube of the backrest frame portion of the full bench seat is subjected to higher deflections. Seat restraint systems for such full bench seats, usually forming a second row of seats in the front-rear direction of the vehicle, must meet stringent regulatory requirements for mitigating risks. Apart from satisfying the regulatory requirements, it is also challenging to ensure that the weight of the vehicle is not increased to an extent that it significantly affects the vehicle performance. Furthermore, there has been identified another problem to ensure compliance with the prevailing seat belt safety standards whilst facilitating a foldability feature to the full bench for expanding storage space when passengers are not seated on the full bench. It has also been identified that modifying existing multi-seater full benches to satisfy one or more of the aforesaid problems would be of economic and implementational advantage.
SUMMARY OF THE INVENTION
[6] Accordingly, the inventors of the present application have devised a multi-seater full bench that addresses one or more of the aforementioned problems, as well as other associated problems identifiable by a person skilled in the art.
[7] Accordingly, an aspect of the present invention provides a multi-seater full bench for a vehicle, said multi-seater full bench comprising: a frame for accommodating at least three seats, said frame having a base frame portion and a continuous backrest frame portion integrally connected to said base frame portion; and a seat belt system for a middle seat positioned between two lateral seats on said multi-seater full bench, said seat belt system having: a retractor mechanism mounted to the backrest frame portion corresponding to said middle seat, said retractor mechanism configured to resiliently bias a flexible primary webbing that locks upon an instantaneous deceleration of the vehicle, three effective anchorage points, including: an upper effective anchorage point for said primary webbing, said upper effective anchorage point connected to the backrest frame portion corresponding to the middle seat and positioned at least 450 mm above the R-point in a global vertical direction for defining a seat belt exit (SBE), and at least 140 mm away from the R-point in a global horizontal direction, and two lower effective anchorage points located below the base frame portion corresponding to lateral sides of said middle seat, each lower effective anchorage point provided at a floor of the vehicle, a secondary webbing for each lower effective anchorage point said secondary webbing having a first end connected to said lower effective anchorage point and a second end connected to a buckle, said buckle disposed at a region of the base frame portion corresponding to a side portion of said middle seat, and a tongue connected to the primary webbing configured to removably engage with one of the buckles, with another one of the buckles being fixedly connected to the primary webbing, for restraining an occupant donned with the seat belt system to said middle seat thereby securing the occupant to said middle seat upon instantaneous deceleration of the vehicle.
[8] According to an embodiment, the backrest frame portion is pivotally connected to the base frame portion, and the backrest frame portion is configured to be foldable relative to the base frame portion.
[9] According to the embodiment, the multi-seater full bench includes a locking mechanism having: at least a pair of locking means attached to lateral sides of one of the backrest frame portion and a body-in-white of the vehicle, and at least a pair of engaging means provided at the other of the backrest frame portion and the body-in-white, said engaging means configured to removably receive the locking means for selectively retaining the backrest frame portion in an unfolded position, and transmitting impact and inertial forces from the frame to the body-in-white upon instantaneous deceleration of the vehicle when the backrest frame portion is in an unfolded position.
[10] According to the embodiment, the upper effective anchorage point is located either leftward or rightward of the R-point corresponding to the middle seat.
[11] According to an embodiment, the multi-seater full bench may be obtained by modifying an existing full bench to attain the upper anchorage point (U) at a height of at least 450 mm from the R-point.
[12] Therefore, the seat belt system of the multi-seater full bench of the present invention provides enhanced safety to a rear middle seat passenger compared to a lap seat belt. In-situ experiments on the multi-seater full bench of the present invention have satisfactorily passed all the safety criteria tests. The results reflect the minimal cost and weight addition to an existing seat frame whilst enhancing safety.
BRIEF DESCRIPTION OF DRAWINGS
[13] Figure 1 illustrates an isometric view of a multi-seater full bench of the present invention including a frame, a seat belt system having a retractor mechanism, an upper effective anchorage point, and two lower effective anchorage points;
[14] Figure 2 illustrates a side view of the multi-seater full bench showing the position of the upper effective anchorage point and a backrest frame portion of the frame before and after an anchorage test;
[15] Figure 3 illustrates a partial top view of the multi-seater full bench showing a disposition of the upper effective anchorage point relative to an R-point;
[16] Figure 4 illustrates an isometric view of the multi-seater full bench provided with cushions to the frame, and depicts the arrangement of lower effective anchorage points on a floor of the vehicle;
[17] Figure 5 illustrates a passenger seated on the multi-seater full bench of the present invention;
[18] Figure 6 illustrates the multi-seater full bench along with a partial portion of a body-in-white of the vehicle, showing a locking mechanism for the backrest frame portion;
[19] Figure 7 illustrates the multi-seater full bench of the present invention shown without the seat belt system, depicting the positioning of reinforcement brackets; and
[20] Figure 8 depicts load observations on the multi-seater full bench disposed as a second row of seats in a front-rear direction of the vehicle, during the seat belt anchorage test conditions.
[21] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.
[22] Throughout the drawings, it should be noted that like reference signs are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
[23] In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present disclosure. One skilled in the art will recognize that various implementations of the present disclosure, some of which are described below, may be incorporated into a number of systems.
[24] However, the systems are not limited to the specific implementations described herein. Further, structures and devices shown in the figures are illustrative of exemplary implementations of the present disclosure and are meant to avoid obscuring the present disclosure. In some embodiments, well-known apparatus structures, and well-known mechanisms are not described in detail.
[25] Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
[26] References in the present disclosure to “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “an embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[27] The terminology used in the present disclosure is only for the purpose of explaining the embodiments and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprising,” “including,” “include”, “has” and “having,” are open ended transitional phrases and therefore specify the presence of stated elements, units and/or components, but do not forbid the presence or addition of one or more other elements, components, and/or groups thereof. The terms “primary” and “secondary” are merely used to indicate different elements but do not indicate any relative importance of the elements unless explicitly stated.
[28] In general, the present invention relates to a multi-seater full bench for a vehicle having a seat belt system for a middle seat disposed between lateral seats. The vehicle may be a passenger car, for example. The full bench includes a frame that comprises a continuous backrest frame portion integrally connected to a continuous base frame portion. The base frame portion and the backrest frame portion may be insert molded or may be manufactured by any other method.
[29] The seat belt system for the middle seat is of three-point type, said seat belt system including a retractor mechanism that resiliently biases a flexible primary webbing, an upper anchorage point for the primary webbing, said upper anchorage point located at the backrest frame portion, and a pair of lower anchorage points located at the floor of the vehicle below sides of the middle seat. A secondary webbing is provided for each lower anchorage point, said secondary webbing having a first end connected to the lower anchorage point and a second end connected to a buckle disposed at a side portion of the middle seat on the base frame portion. The primary webbing has a tongue that engages with one of the buckles, with another one of the buckles being fixed to the primary webbing.
[30] Essentially, the present invention highlights an approach of packaging the retractor mechanism for the middle seat occupant in a full bench seat. The retractor mechanism may be fitted in the backrest frame portion by bracket welding using standard bolts and a primary webbing strap is made to be accessible through the upper effective anchorage point on the frame. The frame may be reinforced in such a way to withstand the load cases of the seat belt system and the prevailing regulatory seat performance parameters. Structural and functional details of the invention will now be described with reference to the drawings.
[31] Referring to Figure 1, the multi-seater full bench for a vehicle comprises a frame (100). The frame (100) is configured to accommodate at least three seats. The frame (100) includes a base frame portion (110) and a continuous backrest frame portion (120) integrally connected to the base frame portion (110). The material of the base frame portion (110) and the backrest frame portion (120) may be stainless steel and the like, but not limited thereto. The multi-seater full bench includes a seat belt system for a middle seat (M) positioned between two lateral seats (S1, S2) [Refer Figure 5].
[32] In the exemplary embodiment, the frame (100) includes three seats, namely a middle seat (M), a right seat (S1) disposed adjacent to the middle seat (M) at the right side of the middle seat (M), and a left seat (S2) disposed adjacent to the middle seat (M) at the left side of the middle seat (M). The base frame portion (110) includes a pair of elongated horizontal end members provided at its ends when seen from a front-rear direction of the vehicle (See Figure 1). Each seat (M, S1, S2) is supported by the frame (100), and the base frame portion (110) of each seat includes a pair of elongated intersecting members for limiting a width of the seat, said elongated intersecting members perpendicularly crossing a portion of the elongated horizontal end members of the base frame portion (110). Therefore, each seat (M, S1, S2) has a finite width along the base frame portion (110) to accommodate a passenger thereon. The backrest frame portion (120) comprises an upper cross tube and a lower cross tube, and preferably further includes intersecting members that intersect the upper cross tube and the lower cross tube to provide structural back support for each of the seats. Further, each seat (M, S1, S2) may be provided with either separate cushions on the base frame portion (110) or with a continuous cushion on the base frame portion (110). Likewise, each seat (M, S1, S2) may be provided with either separate cushions for the backrest frame portion (120) or a continuous cushion for the backrest frame portion (120).
[33] The seat belt system for the middle seat includes a retractor mechanism (130) mounted to the backrest frame portion (120) corresponding to the middle seat. The retractor mechanism (130) is configured to resiliently bias a flexible primary webbing (140) that locks upon an instantaneous deceleration of the vehicle, which may occur during a crash or sudden braking of the vehicle.
[34] The retractor mechanism (130) may be of Emergency Locking Retractor (ELR) type, for example. However, the type of the retractor mechanism (130) is not limited thereto. Any type of retractor mechanism may be used that satisfies regulatory safety standards.
[35] The seat belt system includes three effective anchorage points, namely an upper effective anchorage point (U) and two lower effective anchorage points (L1, L2). The said effective anchorage points (U, L1, L2) are constituted in a three-point belt system. Belt anchorage means the parts of the vehicle structure or the seat structure or any other part of the vehicle to which the seat belt system is secured. Effective anchorage point refers to the point used to determine conventionally the angle of each part of the safety belt in relation to the wearer i.e., the point to which a strap would need to be attached to provide the same lie as the intended lie of the belt when worn, and which may or may not be the actual belt anchorage depending on the configuration of the safety belt hardware at its attachment to the belt anchorage.
[36] Reference is now made to Figures 1, 2 and 3. The upper effective anchorage point (U) is provided for the primary flexible webbing (140). The upper effective anchorage point (U) is connected to the backrest frame portion (120) corresponding to the middle seat and is positioned at least 450 mm above the R-point in a global vertical direction for defining a seat belt exit (SBE). In other words, the upper effective anchorage point (U) is positioned at least at or above a C-plane (CP) defined by a plane perpendicular to the R-point and positioned 450 mm vertically above the R-point. The term “R-point” as is known in the art refers to the seating reference point and is a design point defined by the manufacturer which has co-ordinates determined in relation to the vehicle structure and corresponds to the theoretical positions of the point of torso/legs rotation for the lowest and the rearmost normal position of use given to each seat provided by the vehicle manufacturer. In Figure 2, R-plane (RP) corresponds to a plane that perpendicularly connects the R-point to the C-plane (CP).
[37] In a preferred embodiment, the upper anchorage point (U) is surrounded by a bezel (145) having a through-hole that allows the primary webbing (140) corresponding to a torso portion of a passenger to pass through it while restricting any wear and tear to the webbing (140). The bezel (145) may be made of plastic, for example. To look aesthetically appealing, a snap kind of fitment may be given to the bezel (145) instead of a bolt type fitment.
[38] In an implementation, the multi-seater full bench is provided at a second row among seating rows of a passenger car, as seen from a front direction of the car. This second row is disposed rearward to a driver’s seat in the front-rear direction of the vehicle.
[39] Figure 4 shows a multi-seater full bench provided with cushions for the base frame portion (110) and the backrest frame portion (120). Now referring to Figures 1 and 4, the seat belt system includes two lower anchorage points (L1, L2) provided below the base frame portion (110) corresponding to lateral sides of the middle seat, with each of the lower anchorage points (L1, L2) being provided at a floor of the vehicle. The first lower effective anchorage point (L1) is provided at the right side of the middle seat and the second lower anchorage point (L2) is provided at the left side of the middle seat.
[40] A secondary webbing (150, 160) is provided for each lower effective anchorage point (L1, L2). Each secondary webbing (150, 160) has a first end connected to a lower effective anchorage point (L1, L2) and a second end connected to a buckle (155, 165). The buckle (155, 165) is disposed at region of the base frame portion (110) corresponding to a side portion of the middle seat.
[41] Particularly, a first secondary webbing (150) is provided for the first lower effective anchorage point (L1) and a second secondary webbing (165) is provided for the second lower effective anchorage point (L2). The first end of the first secondary webbing (150) is connected to the first lower anchorage point (L1), and the second end of the first secondary webbing (150) is connected to the first buckle (155). The first buckle (155) is disposed at the right side of the middle seat at the base frame portion (110). Likewise, the first end of the second secondary webbing (160) is connected to the second lower anchorage point (L2), and the second end of the second secondary webbing (160) is connected to the second buckle (165). The second buckle (165) is disposed at the left side of the middle seat at the base frame portion (110).
[42] A tongue (145) is connected to the primary webbing (140) configured to removably engage with one of the buckles, with another one of the buckles being fixedly connected to the primary webbing (140), for restraining an occupant donned with the seat belt system of the present invention to the middle seat, thereby securing the occupant to the middle seat upon instantaneous deceleration of the vehicle. According to the present embodiment, the tongue (145) is removably engaged with the second buckle (165), and the first buckle (155) being fixedly connected to the primary webbing (140). According to the first embodiment, the upper anchorage point (U) is located rightward of the R-point corresponding to the middle seat. The right seat (S1) and the left seat (S2) may be provided with separate seat belts to secure and restrain outboard seat passengers.
[43] However, in an alternative embodiment, the tongue (145) may be removably engaged with the first buckle (155), and the second buckle (165) may be fixedly connected to the primary webbing (140). In such an embodiment, the upper anchorage point (U) may be located leftward of the R-point corresponding to the middle seat.
[44] Further, regulatory requirements can be met by modifying an existing full bench seat frame, particularly the backrest frame portion, in order to obtain the desired position of the upper effective anchorage point (U). Such a modification can be achieved by way of increasing the height of the backrest frame portion in case the vertical distance from the R-point to the upper effective anchorage point (U) is lesser than 450 mm. In other words, the multi-seater full bench may be obtained by modifying an existing full bench to attain the upper anchorage point (U) at a height of at least 450 mm from the R-point in the global vertical direction. For instance, the inventors of the present application have increased the height of an existing frame by 45 mm to attain the C-plane (CP) criteria by 45 mm without significantly altering the aesthetics of the existing frame. The multi-seater full bench may also be obtained by attaching an extension member (not shown) to the backrest frame portion of an existing seat, said extension member extending above the backrest frame portion for accommodating the upper anchorage point (U) at least above 450 mm from the R-point in the global vertical direction. The extension member may be a rod, beam or the like.
[45] In an embodiment, the backrest frame portion (120) is connected at its lateral ends at a shoulder region thereof to the inner side surfaces of the body-in-white of the vehicle, for dissipating inertial and impact loads from the frame (100) to the body-in-white upon a sudden deceleration of the vehicle. This connection may be a permanently fixed connection or a removable connection.
[46] In a preferred embodiment, the backrest frame portion (120) may be pivotally connected to the base frame portion (110), and the backrest frame portion (120) may be configured to be foldable relative to the base frame portion (110). This provides for additional space to store items in the vehicle when there is no rear seat passenger.
[47] In the embodiment, in order to lock the backrest frame portion (120) in an unfolded position, the multi-seater full bench includes a locking mechanism. Referring to Figure 6 showing the multi-seater full bench and a partial portion of a body-in-white of the vehicle (200), the locking mechanism has at least a pair of locking means (170) attached to lateral sides of one of the backrest frame portion (120) and the body-in-white (200) of the vehicle. The locking mechanism further includes at least a pair of engaging means (180) provided at the another one of the backrest frame portion (120) and the body-in-white (200) of the vehicle. In other words, if the locking means (170) are attached to the lateral sides of the backrest frame portion (120), the engaging means are provided at lateral sides of the body-in-white (200) of the vehicle, and vice versa. The engaging means (180) are configured to receive the locking means (170) for selectively retaining the backrest frame portion (120) in the unfolded position.
[48] As shown in Figure 6, the locking means (170) are attached to lateral sides of the backrest frame portion (120) at shoulder regions of the backrest frame portion (120), and the engaging means (180) are provided at the body-in-white (200) of the vehicle. The engaging means (180) are disposed to oppositely face the locking means (170).
[49] In the embodiment, the engaging means (180) are striker rods, and the locking means (170) are latching brackets. Referring to Figure 5 and Figure 6, each latching bracket (170, 180) is operably connected to a respective pull rod / knob (175, 175) that facilitates an engagement of said latching bracket with a corresponding striker rod (180, 180). A suitable fixture gauge may be designed to ensure that the striker rods (180) are fitted on the body-in-white (BIW) correctly.
[50] The locking mechanism helps in transmitting impact and inertial forces from the frame (100) to the body-in-white (200) of the vehicle upon instantaneous deceleration of the vehicle, when the backrest frame portion (120) is in an unfolded position.
[51] In a preferred embodiment, the multi-seater full bench may be provided with reinforcements to maintain the structural integrity of the bench in case of a crash or sudden braking. The reinforcement brackets may be attached or mounted to one or more of the retractor mechanism (130), the seat belt exit (SBE), the primary webbing (140), adjacent portions of the base frame portion (110) and the backrest frame portion (120), and the locking mechanism.
[52] Figure 7 illustrates the multi-seater full bench of the present invention shown without showing the seat belt system, solely for facilitating an understanding of the positioning of the reinforcement brackets. Referring to Figure 7, particulars of the reinforcement brackets according to a preferred embodiment are as follows:
(i) Base marriage brackets (111) provided at lateral side portions of the base frame portion (110) proximate and adjacent to the backrest frame portion (120). The base marriage brackets (111) may be made of steel, particularly made of S550MC material having a thickness of 2.5 mm and attached to the base frame portion (110) by welding.
(ii) Back marriage brackets (121) provided at lateral side portions of the backrest frame portion (120), pivotally connected to the base marriage brackets (111) and located proximate and adjacent to the base frame portion (110). The back marriage brackets (121) may be made of steel, particularly made of S550MC material having a thickness of 2.5 mm and attached to the backrest frame portion (120) by welding.
(iii) Cushion reinforcement brackets (112) provided at lateral edge portions of the base frame portion (110) proximate to the backrest frame portion (120). The cushion reinforcement brackets (112) may be in contact with a portion of the base marriage bracket (111). The cushion reinforcement brackets (112) may be made of steel, particularly made of S420MC material, has a thickness of 2 mm and is welded to the base frame portion (110).
(iv) A retractor mounting bracket (131) welded to the backrest frame portion (120) for mounting the retractor mechanism (130) in place and providing structural support to the retractor mechanism (130). The retractor mounting bracket (131) may be made of steel, particularly made of HC 340LA material and may have a thickness of 2 mm.
(v) A webbing guide reinforcement bracket (141) welded at a top portion of the backrest frame portion (120) proximate to the upper effective anchorage point (U) and below the bezel, which acts as a frame reinforcement to withstand instantaneous loads resulting from a locking of the resiliently biased flexible primary webbing in case of an instantaneous deceleration. The webbing guide reinforcement bracket (141) may have a thickness of 3mm and may be made of steel, particularly made of S550MC material.
(vi) A webbing guide back reinforcement bracket (142) welded adjacent to the webbing guide reinforcement bracket (141) next to the bezel. The webbing guide back reinforcement bracket (142) may have a thickness of 2 mm and may be made of steel, particularly made of S420MC material.
(vii) Latch reinforcement brackets (171) welded to the latching brackets (170) positioned at shoulder regions of the backrest frame portion (120). The latch reinforcement brackets (171) may have a thickness of 2.5 mm and may be made of steel, particularly made of S420MC material.
[53] The brackets referred to in the foregoing may be made of different materials, may have different thicknesses that what has been mentioned, and may be assembled by methods other than welding.
[54] The multi-seater full bench may also include headrest frame portions (H1, H2) to mount headrests for outboard passengers seated adjacent to the middle seat passenger on either sides. The headrest frame portions (H1, H2) may be mounted to the top of the backrest frame portion (120).
[55] Each anchorage should meet dimensional requirement and strength requirement to comply with the test standards. Table 1 shown herein below illustrates the different parameters during a seat belt anchorage test.
Table 1: Second row seat belt anchorage test parameters
Load Cell Anchorage Location Loading Angle Holding Time, s Load Applied, kN
LC1 LH Torso 10.7⁰ 5.4 13.5 ± 0.2
LC2 Middle Torso 11.2⁰ 6 13.5 ± 0.2
LC3 RH Torso 12.7⁰ 5.2 13.5 ± 0.2
LC4 LH Lap 9.6⁰ 5.8 13.5 ± 0.2
LC5 Middle Lap 8.5⁰ 1.3 13.5 ± 0.2
LC6 RH Lap 9.2⁰ 3.3 13.5 ± 0.2
LC7 Seat CG 0⁰ 5.4 6
[56] Figure 8 depicts load observations on the multi-seater full bench disposed as a second row of seats in a front-rear direction of the vehicle, during the seat belt anchorage test conditions specified by Table 1. Load (kN) vs time (s) graph has been plotted to study the behavior of the seat under different loading conditions at different instants of time.
[57] Table 2 shown herein below lists the different used criteria, the mounting locations, and the necessary passing requirements during experimentation upon a multi-seater full bench of an M1 category vehicle.

Table 2: Seat belt anchorage test for M1 category vehicle
Criteria Location Requirement
Seat Torso Angle In-house Need to be close to 25 degrees (also original equipment manufacturer (OEM) specific)
Loading criteria If seat belt anchorages mounted on the seat structure
Center of gravity (COG) of the seat 20 * Seat Weight
3-point belt anchorages having retractor with pulley [6] 13.5 ± 0.2 KN
3-point belt anchorages and having no retractor mechanism 13.5 ± 0.2 KN
Load duration Achieve full load application within 30s and withstand that load till 0.2s.
Passing criterion Regulatory No breakage of anchorages and surrounding area during and after the test.
Gap between outboard and inboard seats after the test should be more than 240mm.
Mechanism to be operated manually once to leave an occupant.
Effective upper anchorage point should not cross 450mm C-plane from the R-point.
Effective upper anchorage point should not cross the R-plane.
In-house Displaced effective anchorage point upon application of load, should remain at 20 percent of the initial position from R-plane.

[58] Now referring to Figure 2, the broken lines depict a state of the backrest frame portion after the application of the load as described in Table 2. The final state of the backrest frame portion is indicated by the reference 120A, and the final position of the seat belt exit (SBE) is indicated by the reference SBE’. As can be seen from Figure 2, the effective upper anchorage point (U) does not cross the C-plane and the R-plane upon loading as per the test conditions.
[59] The multi-seater full bench of the present invention was subjected to pass the test standards as described in Table 3 shown herein below.
Table 3: Seat belt anchorage test for M1 category vehicle
Criteria Requirement
Energy dissipation test for seat back and head restraint

Loading Criteria Head form impacted at 24kmph
Load Duration Deceleration of head form shall be< 80g continuously for more than 3ms.
Passing Criteria No dangerous edge shall protrude out during and after the test.
Strength of seat back and adjustment system

Loading criteria 530 Nm
Passing Criteria No failure shall occur in the seat frame or in the seat anchorage, the adjustment and displacement systems or their locking devices during and after the test.
Strength of the Seat Anchorage, and the Adjustment, Locking and displacement Systems (Sled test)

loading criteria Deceleration 20g is applied to whole shell of vehicle for 30 ms.
Passing Criteria No failure shall occur in the seat frame or in the seat anchorage, the adjustment and displacement systems or their locking devices during and after the test.
No release of the locking systems shall occur during the tests.
Head Restraint performance test

Loading criteria Force creating moment of 373 Nm is applied on Back Seat by SAE J826 Back Pan to create displaced torso, then a force creating moment of 373Nm is applied by head form at 65mm below the top of the headrest.
Passing Criteria Maximum displacement <102mm
No Breakage to the head restraint and their anchorages during and after the test.

[60] The multi-seater full bench of the present invention was found to satisfy the criteria of the test standards described in Table 3. Therefore, by satisfying criteria set forth by the above tables 1-3, the multi-seater full bench of the present invention meets the requirements whilst ensuring safety to a passenger seated on the middle seat (M) on the full bench and meeting overall perceived quality requirements.
[61] The present invention described in the foregoing allows for packaging of the retractor mechanism (130) with minimum modifications on existing full benches without significantly affecting the base architecture. The multi-seater full bench has been designed to fulfil the requirements of central manufacturing engineering (CME) like seat insertion in the vehicle, striker rod mounting, and seat accessibility.
[62] The seat belt system of the multi-seater full bench of the present invention provides enhanced safety to a rear middle seat passenger compared to a lap seat belt. In-situ experiments performed on the multi-seater full bench of the present invention have proved satisfactory passing criteria to the tests. The results reflect the minimal cost and weight addition to an existing seat frame whilst enhancing safety.
[63] Further, regulatory requirements can be met by modifying an existing full bench seat frame. Therefore, the multi-seater full bench of the present invention may be regarded as cost effective in view of new structure development. Furthermore, the present invention can also be adopted with a folding feature of the existing frame.
[64] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.
, Claims:

1. A multi-seater full bench for a vehicle, said multi-seater full bench comprising:
a frame (100) for accommodating at least three seats, said frame having a base frame portion (110) and a continuous backrest frame portion (120) integrally connected to said base frame portion (110); and
a seat belt system for a middle seat (M) positioned between two lateral seats (S1, S2) on said multi-seater full bench, said seat belt system having:
a retractor mechanism (130) mounted to the backrest frame portion (120) corresponding to said middle seat, said retractor mechanism (130) configured to resiliently bias a flexible primary webbing (140) that locks upon an instantaneous deceleration of the vehicle,
three effective anchorage points, including:
an upper effective anchorage point (U) for said primary webbing (140), said upper effective anchorage point (U) connected to the backrest frame portion (120) corresponding to the middle seat and positioned at least 450 mm above the R-point in a global vertical direction for defining a seat belt exit (SBE), and at least 140 mm away from the R-point in a global horizontal direction, and
two lower effective anchorage points (L1, L2) located below the base frame portion (110) corresponding to lateral sides of said middle seat, each lower effective anchorage point provided at a floor of the vehicle,
a secondary webbing (150, 160) for each lower effective anchorage point (L1, L2), said secondary webbing (150, 160) having a first end connected to said lower effective anchorage point (L1, L2) and a second end connected to a buckle (155, 165), said buckle disposed at a region of the base frame portion (110) corresponding to a side portion of said middle seat, and
a tongue (145) connected to the primary webbing (140) configured to removably engage with one of the buckles, with another one of the buckles being fixedly connected to the primary webbing, for restraining an occupant donned with the seat belt system to said middle seat thereby securing the occupant to said middle seat upon instantaneous deceleration of the vehicle.

2. The multi-seater full bench as claimed in claim 1, wherein the upper effective anchorage point (U) is located either leftward or rightward of the R-point corresponding to the middle seat (M).

3. The multi-seater full bench as claimed in claim 1, wherein the backrest frame portion (120) is pivotally connected to the base frame portion (110), and the backrest frame portion (120) is configured to be foldable relative to the base frame portion (110).

4. The multi-seater full bench as claimed in claim 3, wherein the multi-seater full bench includes a locking mechanism having:
at least a pair of locking means (170) attached to lateral sides of one of the backrest frame portion (120) and a body-in-white (200) of the vehicle, and
at least a pair of engaging means (180) provided at another one of the backrest frame portion (120) and the body-in-white (200), said engaging means (180) configured to removably receive the locking means (170) for selectively retaining the backrest frame portion (120) in an unfolded position, and transmitting an impact and/or inertial force from the frame (100) to the body-in-white (200) upon sudden deceleration of the vehicle when the backrest frame portion (120) is in an unfolded position.

5. The multi-seater full bench as claimed in claim 4, wherein the locking means (170) are attached to lateral sides of the backrest frame portion (120) at shoulder regions of the backrest frame portion (120), and the engaging means (180) are provided at the body-in-white (200) of the vehicle, said engaging means (180) oppositely facing said locking means (170).

6. The multi-seater full bench as claimed in claim 5, wherein the engaging means (180) are striker rods and the locking means (170) are latching brackets, each latching bracket being operably connected to a respective pull rod (175) that facilitates an engagement of said latching bracket with a corresponding striker rod.

7. The multi-seater full bench as claimed in claim 1, wherein the multi-seater full bench comprises reinforcement brackets (111, 121, 112, 131, 141, 142) mounted or attached to one or more of the retractor mechanism (130), the seat belt exit (SBE), the primary webbing (140), and adjacent portions of the base frame portion (110) and the backrest frame portion (120),

8. The multi-seater full bench as claimed in any one of claims 4 to 7, wherein the multi-seater full bench comprises reinforcement brackets (171) connected to the locking mechanism.

9. The multi-seater full bench as claimed in claims 1, wherein the multi-seater full bench is obtained by modifying an existing full bench to attain the upper anchorage point (U) at a height of at least 450 mm from the R-point in the global vertical direction.

10. The multi-seater full bench as claimed in claim 1, wherein the multi-seater full bench includes an extension member attached to the existing seat, said extension member extending above the backrest frame portion (120) for accommodating the upper anchorage point (U) at least 450 mm from the R-point in the global vertical direction.