Patent Publication Number: US-2006001248-A1

Title: Safety device used in case a vehicle rolls over

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates to a safety device used in case a vehicle rolls over, and in particular to such a safety device that comprises at least two curved bars, each curved bar having a first end and a second end, said bars being movable from a retracted position to a deployed position in case the vehicle rolls over.  
      In particular, such a device is designed for motor vehicles of the “convertible” type which are convertible into open-top vehicles, in which the roof, made up of a plurality of portions, can be either overlying the passenger compartment, when the roof is “up”, or else stowed away in the luggage compartment when the roof is “down” in the open-top configuration.  
      In such vehicles, it is essential to have a luggage compartment whose volume is as large as possible, in particular for stowing away the roof elements.  
      A safety device is already known, in particular from Document FR-0 451 302, whose various component parts are arranged such that the device is compact and is disposed in the top portion of the luggage compartment, thereby making it possible to make considerable stowage length available inside said compartment.  
     SUMMARY OF THE INVENTION  
      An object of the invention is to improve a device of that type by proposing a safety device in which the geometrical shape of the bars is organized to optimize the stowage volume inside the luggage compartment.  
      To this end, and according a first aspect, the invention provides a safety device used in case a vehicle rolls over, said safety device comprising at least two curved bars, each curved bar having a first end and a second end, a first portion of the bar extending from the first end, and a second portion of the bar extending from the second end, said bars being movable from a retracted position to a deployed position in case the vehicle rolls over, the first ends of said bars being hinged to a support, in which safety device the second portion of each bar is substantially rectilinear, said device further comprising two guide boxes, each box being provided with an elongate orifice for receiving said second portion, said orifice extending substantially transversely relative to said second portion, said box being designed to be secured to a structural portion of the vehicle.  
      Such a device offers the advantage of making it possible to procure additional available space, which can advantageously be used for stowing retractable roof elements, or as additional stowage space in the rear trunk of the vehicle. It also makes it possible to simplify manufacturing by avoiding superfluous curving, and thus to reduce the cost of the device.  
      In one embodiment, the device further comprises:  
      a pre-stressed system for deploying each bar;  
      a trigger system that is activated in case the vehicle rolls over;  
      at least one locking member that maintains the pre-stress and that is released by means of the trigger system, thereby releasing each bar from its retracted position; and  
      at least two anti-reverse locks systems, each of which is disposed between the second end of each bar and a structural portion of the vehicle in order to prevent the bar from retracting when said bar is in the deployed position.  
      Each anti-reverse locks system may be a ratchet system, and in particular, each ratchet system is disposed inside the corresponding bar, in the vicinity of the second end of said bar, each ratchet system being arranged to co-operate with elements of complementary shape integral with or secured to a structural portion of the vehicle.  
      In one embodiment, the first end of each bar is hinged to a common central plate so that each of said two bars extends on a respective side of said plate, from a common face of said plate, and substantially symmetrically about a plane, a control device for locking and releasing each bar being provided on the same face of said plate, said hinging of each bar being achieved by means of a bearing comprising a stationary portion secured to the plate, and a moving portion secured to the first end of the bar, the plate being designed to be fixed to a structural element of the vehicle.  
      The stress, locking, and control members are thus grouped together very compactly on a common assembly plate. On the same one of its faces, the plate also supports the bearings for hinging the roll-bars. Therefore, instead of being disposed between the seat back and the luggage compartment, the locking, control, and pre-stress devices can be disposed in the top portion of said luggage compartment whose length is thus increased over most of its height.  
      In particular, the moving portion of the bearing is provided with a shape element which co-operates with the locking member of the locking system such as:  
      firstly to hold the bars stationary in their retracted and pre-stressed position by means of the locking member engaging with the shape element; and  
      secondly to release the curved bars by means of the locking member disengaging from the shape element.  
      Also in a particular embodiment, the pre-stressed system is disposed inside the stationary portion of the bearing and in the immediate vicinity of the moving portion of the bearing.  
      Also in a particular embodiment, the control devices for locking and releasing each bar are actuated by a common actuator.  
      In a second aspect, the invention provides a motor vehicle including a structural element and at least one such safety device, said device further comprising two guide boxes, each box being situated on a respective one of the sides of the vehicle and being secured to a portion of said structural element.  
      In one embodiment, the two guide boxes are interconnected via a link element that also supports the plate.  
      In particular, the assembly comprising the safety device and the link element is fixed to the structural element.  
      More particularly, said vehicle may include one or more roof elements that are retractable into a stowage position behind the seats, at least one of the roof elements being received in part under said structural element when in the retracted position.  
      In a third aspect, the invention provides a method for assembling such a vehicle, which method includes a first step for assembling an assembly comprising the safety device and the link element, and then a second step for mounting said assembly onto said structural element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      A particular embodiment of the invention is described below by way of non-limiting example and with reference to the accompanying diagrammatic drawings, in which:  
       FIG. 1  is a rear perspective view of a safety device for a motor vehicle, said device comprising two roll-bars, the device being incorporated into the passenger compartment of a motor vehicle;  
       FIGS. 2   a  and  2   b  are elevation views of one side of the device of  FIG. 1 , the roll-bar being shown respectively in the retracted position ( FIG. 2   a ) and in the deployed position ( FIG. 2   b );  
       FIG. 3  is an exploded view of the various elements forming one side of the safety device of  FIG. 1 ;  
       FIG. 4  is an enlarged section view of the guide box and of the ratchet system on line A-A of  FIG. 2   b;    
       FIG. 5  is a section view on line B-B of  FIG. 4 ;  
       FIG. 6  is a section view from above on line VI-VI of  FIG. 7 , showing the roll-bar control assembly;  
       FIG. 7  is a section view taken along line VII-VII of  FIG. 6 ;  
       FIG. 8  is section view taken along line VIII-VIII of  FIG. 6 ;  
       FIG. 9  is a section view taken along line IX-IX of  FIG. 6 ; and  
       FIGS. 10   a  and  10   b  are perspective views respectively from the rear and from the front of the safety device when said safety device is in the form of a pre-assembled module ready to be mounted into the passenger compartment of the vehicle. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  shows two roll-bars  1  and  1 ′, each of which is constituted by a curved bar or tube forming two branches  2  &amp;  3 ,  2 ′ &amp;  3 ′.  
      The roll-bars  1  and  1 ′ are hinged symmetrically along two opposite edges of one face of a plate  4 . Since the two roll-bars are symmetrical, only the roll-bar  1  and what is related to it is described below.  
      The branch  3  of the roll-bar  1  has its free end or “first” end hinged at  5  to the plate  4  so as to pivot in its plane relative to said plate.  
      The bar portion  7  situated between the second end  8  of the bar  2  and the curved portion  9  is substantially rectilinear.  FIG. 2   a  makes it possible to compare volume occupied by the bar when the portion starting from the second end is rectilinear, with the volume occupied by a bar in which that portion is curved, shown in dot-dash lines. Clearly, the curvature of the bar implies its protrusion into the vehicle, thereby causing space to be lost, represented by the distance D.  
      In addition, the guide box  10  for guiding the bar is secured to a structural portion of the vehicle, and it is provided with an orifice  11  of elongate shape for receiving the rectilinear portion  7  of the bar  2 , the orifice  11  extending substantially transversely relative to the rectilinear bar portion, along direction X.  
      With reference to FIGS.  1  to  5 , a description follows of the ratchet system that contributes to forming the anti-reverse lock system. This system is disposed inside the bar  2 , in the vicinity of its second end  8 .  
      The ratchet system comprises teeth  12  formed on the ratchets  13 , which teeth co-operate with notches  14  between teeth that are formed on pads  15 . Two substantially rectangular pads  15  are provided on either side of the bar  2 , so that the teeth of each pad  15  face the periphery of the bar  2 .  
      The pads  15  extend in two parallel planes that are substantially perpendicular to the axis Y along which the vehicle advances. The pads  15  are fixed inside the guide box  10 .  
      The ratchet system (see  FIG. 3 ) includes a support  16  having a cylindrical portion  17  which is designed to be inserted into the second end  8  of the bar  2 . The cylindrical portion  17  is provided with two orifices  18  receiving a pin  19  that serves as a hinge for the two ratchets  13 . An inside portion of the cylindrical portion  17  is hollow so as to form two parallel flat parts  20  serving as abutments for the outside faces of the ratchets  13 . Thus, the two ratchets are inserted between the two flat parts  20 , thereby guaranteeing that the ratchets  13  are guided and held laterally in a satisfactory manner.  
      The ratchet system also includes a V-shaped blade spring  21 . At its end opposite from its teeth  12 , each ratchet  13  has an end  22  formed of an L-shaped finger. The short branch of the L-shape is inserted into a slot  23  provided in the end of each of the branches of the blade spring  21 . In this way, in operation, the two ratchets  13  are pushed towards the outside of the bar  2  under the action of the blade spring  21 . The teeth  12  of the ratchets  13  pass through two oblong-shaped holes  24  provided in the vicinity of the second end  8  of the bar  2 , so that the teeth  12  project beyond the periphery of the bar  2 .  
      As shown, the hinge pin  19  further makes it possible to fix the ratchet system to the end of the bar  2 . In a variant, it is possible to make provision for the cylindrical portion  17  of the support  16  to be forced fitted into the bar  2 , the entire ratchet system having been pre-assembled.  
       FIGS. 4 and 5  show the three teeth  12  of each ratchet  13  engaged in the three notches  14  of complementary shape formed in the pads  15 , the bar  2  being, as shown in  FIG. 2   b , in the deployed position. It should be noted that, when operation of the device is tested, the ratchets  13  can be unlocked merely by manually pushing the fingers  22  on the two ratchets  13  towards each other in order to disengage the ratchets  13  from the pads  15 , thereby enabling the bar  2  to be moved into its retracted position ( FIG. 2   a ).  
      In addition, provision is made for the width of the pads  15  to be greater than the thickness of the teeth  12  on the ratchets  13  so that the ratchets  13  can make use of the entire width of the pads  15  in order to lock onto the teeth on the pads  15 . Such an arrangement makes it possible to absorb a certain amount of inaccuracy, resulting from manufacturing and assembly tolerances, in the positions of the pads  15  relative to the ratchets  13 . Therefore, the rectilinear shape of the portion  7  of bar  2  and the ratchet system can move freely between the pads  15 . It is not therefore necessary to provide operating tolerance along direction X.  
      In addition, the fact that the ratchets  13  are hinged to the bar and can move along direction Y makes it possible to absorb certain positioning errors of the bar relative to the pads  15 .  
      These two characteristics make it possible to accept manufacturing and assembly tolerances that are quite broad, thereby contributing to simplifying the device. In addition, said characteristics make it possible to remove the risks of the bar sticking or jamming as it is being deployed, because the bar does not encounter any obstacles along direction X, and can move freely along direction Y by means the ratchets  13  tilting.  
      In addition, the pads  15  are disposed on either side of the bar  2  so that their respective teeth, which are substantially rectilinear in shape, extend perpendicularly to the axis of the rectilinear portion  7  of the bar  2  when said bar is in the deployed position ( FIG. 2   b ). Thus, in case the vehicle rolls over, the component of the forces acting along the axis of the rectilinear portion  7  of the bar  2  acts, via the teeth  12  on the ratchets  13 , on the faces of the teeth on the pads  15  that are perpendicular to it.  
      The three arrows referenced C 1 , C 2 , C 3  on  FIG. 2   b  show how the force acting on the bar changes during the rollover of the vehicle, when said vehicle pivots about the axis Y counterclockwise. The arrow C 1  represents the force acting on the bar when the vehicle is still on its side, the arrow C 2  represents the force when the vehicle is in an intermediate position, and the arrow C 3  represents the force once the vehicle has pivoted through 180 degrees. The device of the invention thus makes it possible to absorb optimally the forces acting on the bar while the vehicle is rolling over, by distributing them both over the bearing  25  of the plate  4  and over the ratchet system.  
      As the vehicle rolls over, the force acting on the bar is essentially absorbed by the bearing (arrow C 1 ), then it is distributed between the bearing and the ratchet system (arrow C 2 ), and finally it is absorbed essentially by the ratchet system (arrow C 3 ). In this way, the components of the forces acting on the first and the second portions of bar act essentially in compression, thereby making it possible to optimize the crush resistance of the bar relative to said forces, as the vehicle rolls over. The rectilinear shape of the second bar portion makes it possible to avoid buckling stresses that inevitably occur in curved bars. This provision makes it possible to improve the crush resistance of the device.  
      Reference is made to FIGS.  6  to  9  which show the control members for controlling the roll-bars.  
      The free end is fixed to a tube  26  engaged in the bearing-forming tubular portion  25  of the plate  4 . A pre-stress spring  27  is disposed between the tube  26  and the tubular portion  25 , one of its ends being fixed to the tube  26  and its other end being fixed to the tubular portion  25 . The spring is pre-stressed when the roll-bar is in its retracted position.  
      The end of the tube  26  that extends beyond the tubular portion  25  is provided with a notch  28 , into which a locking finger  29  can engage in order hold the roll-bar in the retracted position.  
      The locking finger  29  belongs to a control part  30  that is engaged in a guide part  31  which is secured to the plate  4 . A control cam  32  extends from the part  30  substantially perpendicularly to the plate  4 .  
      The control cam  32  is organized to co-operate with a locking control fork  33  mounted at the free end of a U-shaped rod  34  of a control actuator  35 . The locking fork  33  is guided by grooves  36  formed in the outside walls of the tubular portions  25 .  
      Finally, a return spring  37  urges the locking parts  30 ,  30 ′ back against the action of the locking fork  33 .  
      When the roll-bars are to be deployed, the actuator  35  pushes the locking fork  33  so that the cams  32 ,  32 ′ cause the parts  30 ,  30 ′ to slide in the guide part  31 . Therefore, the locking fingers  29 ,  29 ′ disengage from the notch  28  and the springs  27 ,  27 ′ cause the roll-bars to pivot and thus to be deployed.  
      The above-described control assembly offers the advantage of being very compact. Locking is achieved directly between the tube  26  and the bearing-forming tubular portion  25 . In addition, the pre-stress spring  27  is disposed in the bearing.  
      In addition, the plate  4  supports both of the bearings so that it is possible to use a single, common actuator  35 , offering the advantage of reducing the cost of the assembly. The plate  4  incorporates, inter alia, the functions of pre-stressing, locking, and triggering.  
       FIGS. 10   a  and  10   b  show a safety device of the invention including two guide boxes  10 , each box being designed to be situated on one of the sides of the vehicle, by being secured to a portion of the structural element of the vehicle. The two guide boxes are interconnected via a transverse and substantially horizontal link element  38  which also supports the plate  4 . The assembly comprising the safety device and the link element can advantageously be pre-assembled so as to form a module that is easy to mount on the structural element in the passenger compartment of the vehicle.