Abstract:
A vehicular hood device has a hinge serving also as a coupling link mechanism. The hinge in a usual time allows a hood to make opening and closing movements about a hinge pin connecting a second link to the hood. When an obstacle collided with the vehicle to lift the hood by an actuator, the hinge enables the extended first and second links to determine a hood raise position. The hinge includes a stopper pawl. The stopper pawl has rigidity designed to be deformable by operation of the actuator but not to be bent by a usual hood opening and closing force, thus preventing the hood from floating during normal operation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to vehicular hood devices and, more particularly, to a vehicular hood device designed to lift a hood to enable sufficient deformation of the hood for impact absorption. 
     2. Description of the Related Art 
     Known vehicular hood devices include those designed to lift a hood by a predetermined amount and hold it at the lifted position when a traveling vehicle collides with an obstacle. The lift of the hood increases the downward deformable amount, thereby making it possible to increase the amount of energy absorption upon collision. An example of such a vehicular hood device is disclosed in Japanese Patent Laid-Open Publication No. HEI-10-258774 entitled “JUMP-UP HOOD”. This example hood device will be explained with reference to FIG. 25 hereof. 
     In FIG. 25, the.conventional hood device  200  is shown in its closed state. The vehicular hood device  200  includes a bracket  202  mounted on the vehicular body  201 , a guide hole  202   a  formed in the bracket  202 , a link  205  having a lower end attached in the guide hole  202   a  through a lower pin  203 , and a hood arm  207  to which an upper end of the link  205  is coupled through an upper pin  206 . 
     The bracket  202  is attached to a lock piece  211  via a fixing pin  210 . A tension spring  214  is hooked to the lock piece  211  so that a pawl  212  of the lock piece  211  is pressed on the upper pin  206 . 
     This holds the upper pin  206  in a U-groove  202   b  of the bracket  202  thereby preventing the link  205  from rising. By the prevention against rise in the link  205 , the hood  208  in the usual time can be prevented from floating and hence chattering of the hood  208 . 
     Meanwhile, in the event the vehicle collide with an obstacle, the pawl  212  of the lock piece  211  is disengaged from the upper pin  206  to make free the link  205  thereby making it possible to lift the hood  208  up to a predetermined rise position. With reference to the next figure, explanation is made on the example to lift the hood  208 . 
     Reference is made next to FIG. 26 showing the conventional vehicular hood device  200  in a state of raising the hood  208 . When the vehicle collides with an obstacle, an actuator (not shown) operates to apply a lift force to the hood  208 . Simultaneously, an unlock force F is applied to the lock piece  211  as shown at an arrow, to rotate the lock piece  211  about the fixing pin  210  as shown at an arrow (a). The pawl  212  of the lock piece  211  is disengaged from the upper pin  206  to make free the link  205 . 
     Due to this, the upper pin  206  rises matched to the hood  208  as shown at the arrow (b) while the lower pin  203  moves along the guide hole  202   a  as shown at an arrow (c). As a result, the hood  208  is lifted by a predetermined amount to increase the downward deformable amount of the hood  208  and hence the absorption amount of collision energy. 
     However, in order to eliminate the chatter of the hood  208  in the usual time, the upper pin  206  must be locked by the pawl  212  of the lock piece  211 . Thus, required are the lock piece  211  as well as the tension spring  214  to hold the lock piece  211  in its lock position. 
     In order to lift the hood  208  upon collision of the vehicle, the lock piece  211  in the lock position must be operated to an unlock position. For this reason, there is a need for an operation mechanism to operate the lock piece  211  into an unlock state. 
     Accordingly, there is increase in the number of parts for the vehicular hood device  200 . This in turn constitutes a factor of mount-up of cost. 
     In the meanwhile, generally, there are cases for a vehicle, such as an automobile, where the hood is opened in the usual state in order for maintenance or inspection in the engine compartment. In the vehicular hood device  200 , when the hood  208  is opened, there is a necessity of keeping the upper pin  206  in a state held in the U-groove  202   b  of the bracket  202 . In this state, a hood lock mechanism (not shown) at the front of the hood  208  is operated to release the locking and open the hood  208  about the upper pin  206  as an axis as shown at an arrow. This allows for engine compartment maintenance and inspection. 
     Herein, in order to conduct engine compartment maintenance and inspection, the hood  208  in opening is halted in a predetermined position and the hood  208  is restricted in opening not to be opened furthermore. For restricting the opening of the hood  208 , there is a need to provide hood opening-prevention means as an exclusive member. This however results in hindrance to the size and weight reduction in the vehicular hood device  200 . 
     In addition, there is known as a vehicular hood device of this kind, for example, a “vehicular hood device” in Japanese Patent Laid-open No. 315266/1997, the art of which will be explained in the next figure. 
     In FIG. 27A, when the vehicle collides against an obstacle, the rod  301  of the actuator  300  starts to rise as shown at an arrow. The rod  301  is attached to rod holding means  302  (stopper piece  303 , compression spring  304  and holding piece  305 ) wherein the stopper piece  303  is extended outside of the rod  301  by the compression spring  304 . 
     In FIG. 27B, the rod  301  is further raised so that the stopper piece  303  abuts against a housing  300   a  of the actuator  300  and the stopper piece  303  enters a groove  306  of the rod  301 . 
     In FIG. 27C, the rod  301  is projected to its upper limit to lift the hood (not shown) by a predetermined amount. Simultaneously, the stopper piece  303  gets over the housing  300   a  of the actuator  300 , and the stopper piece  303  extends from the groove  306  to the outside of the rod  301 . 
     Due to this, the stopper piece  303  abuts against a surface of the housing  300   a  to hold the rod  301  at the upper limit, thereby holding the hood at a position lifted by a predetermined amount. 
     However, in order to hold the hood in the position lifted by a predetermined amount, the rod holding means  302  must be structured by the stopper piece  303 , the compression spring  304  and the holding piece  305  to assemble the stopper piece  303 , the compression spring  304  and the holding piece  305  in the groove  306  of the rod  301 . This accordingly complicates the structure of the vehicular hood device. 
     Meanwhile, because the rod  301  is comparatively thin, it takes time to form a groove  306  in the thin rod  301  or assemble the stopper piece  303 , compression spring  304  and holding piece  305  in the groove  306 . Accordingly, it is difficult to enhance the producibility of the vehicular hood devices, which raises a factor of cost increase. 
     On the other hand, it is to be considered that, when the vehicle collides with an obstacle to lift the hood at its rear part by a predetermined amount, an urge force be acted upon the hood in a direction of from the front to rear of the vehicle. In this case, there is a fear of moving of the hood because the rear part thereof is in float. For this reason, there is a fear that the hood at the rear part nears toward the front windshield by a required amount or more. It is desired to provide a structure not to near the rear part of the hood toward the front windshield by a required amount or more. 
     With such a structure, the vehicular hood device is further complicated in structure resulting in a factor of mount-up of cost. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a vehicular hood device which is capable of reducing a number of parts and suppressing the increase in cost. 
     Another object of the present invention is to provide a vehicular hood device reduced in size and weight. 
     Still another object of the present invention is to provide a vehicular hood device which is capable of holding the hood at a lifted position by a simple structure and preventing the lifted hood from approaching the windshield beyond a predetermined amount by a simple structure. 
     According to a first aspect of the present invention, there is provided A vehicular hood device comprising a first link attached swingably to a bracket on a vehicle via a pin, a second link attached swingably to the first link through a coupling pin and a hood provided at a front part of the vehicle and attached to the second link via a hinge pin, the hood being normally capable of opening and closing actions about the hinge pin with the first and second links folded, the hood being designed to be lifted upon collision of the vehicle with an obstacle, by an action of an actuator, the first and second links being extendible upon the collision to determine a raise position of the hood, characterized in that it further comprises: a stopper pin for connecting the second link to the bracket with the first and second links folded, the stopper pin having strength set not to be cut during the opening and closing actions of the hood but to be cut upon operation of said actuator. 
     By connecting the second link to the bracket by the stopper pin, the hood in a usual situation is prevented from floating. The mere provision of the stopper pin can prevent chattering due to floating of the hood. Consequently, because the chattering due to hood floating can be prevented by a simple structure, the number of parts can be reduced. 
     The prior art requires lock release by an operation mechanism when extending the coupled link. Due to this, an operation mechanism is required as an exclusive member for lock release thus increasing the number of parts. In contrast, the present invention, when the actuator is operated, cuts the stopper pin by a lift force thereof to release the lock, thus eliminating the necessity of a special operation mechanism for releasing the lock. Accordingly, the number of parts can be reduced furthermore. 
     According to a second aspect of the invention, there is provided a vehicular hood device comprising a first link attached swingably to a bracket on a vehicle via a pin, a second link attached swingably to the first link via a coupling pin, and a hood provided at a front part of the vehicle and attached to the second link via a hinge pin, the hood being normally capable of opening and closing actions about the hinge pin with the first and second links folded, the hood being designed to be lifted, upon collision of the vehicle with an obstacle, by an action of an actuator, the first and second links being extendible upon the collision to determine a raised position of the hood, characterized in that it further comprises: a stopper pawl for coupling the second link to the bracket with the first and second links folded, the stopper pawl having rigidity being set to maintain the coupling during the opening and closing actions of the hood and to release the coupling upon operation of the actuator. 
     By connecting the second link to the bracket by the stopper pawl, the hood in a usual situation is prevented from floating. The mere provision of the stopper pawl can prevent chattering due to floating of the hood. Consequently, because the chattering due to hood floating can be prevented by a simple structure, the number of parts can be reduced. 
     The prior art requires lock release by an operation mechanism when extending the coupled link. Due to this, an operation mechanism is required as an exclusive member for lock release thus increasing the number of parts. In this respect, the present invention when the actuator is operated disengages the stopper pawl from the second link by a lift force thereof to thereby release the lock, thus eliminating the necessity of a special operation mechanism for releasing lock. Accordingly, the number of parts can be reduced furthermore. 
     According to a third aspect of the invention, there is provided a vehicular hood device comprising a first link attached swingably to a bracket on a vehicle via a pin, a second link attached swingably to the first link via a coupling pin, and a hood provided at a front part of the vehicle and attached to the second link via a hinge pin, the hood being normally capable of opening and closing actions about the hinge pin with the first and second links folded, the hood being designed to be lifted, upon collision of the vehicle with an obstacle, by an action of an actuator, the first and second links being extendible upon the collision to determine a raised position of the hood, characterized in that it further comprises: a stopper mechanism provided between the hood and the bracket, the stopper mechanism including members arranged such that when the hood is opened a predetermined angle, they abut against each other to prevent the hood from further opening. 
     A stopper mechanism is provided between the hood and the bracket. The provision of the stopper mechanism can prevent the hood from opening further when the hood in a usual situation is opened by a constant angle. In this manner, because the structure merely provided with the stopper mechanism between the hood and the bracket can prevent the hood from opening by a constant angle or greater, this thus simplifies the structure of the vehicular hood device. 
     According to a fourth aspect of the invention, there is provided a vehicular hood device comprising a first link attached swingably to a bracket on a vehicle via a pin, a second link attached swingably to the first link via a coupling pin, and a hood provided at a front part of the vehicle and attached to the second link via a hinge pin, the hood being normally capable of opening and closing actions about the hinge pin with the first and second links folded, the hood being designed to be lifted, upon collision of the vehicle with an obstacle, by an action of an actuator, the first and second links being extendible upon the collision to determine a raise position of the hood, characterized in that it further comprises: a first link stopper provided between the first link and the bracket and a second link stopper provided between the second link and the first link, and in that when the first and second links are extended by the action of the actuator, the first link stopper prevents the first link from inclining toward a rear side of the vehicle and the second link stopper prevents the second link from inclining toward a front side of the vehicle. 
     After the first and second links are extended to lift the hood, the second link stopper prevents the second link from inclining toward a front of the vehicle. Accordingly, the first and second links are prevented from being folded to hold the hood in a lifted position. In this manner, the mere provision of the second link stopper can hold the hood in a lifted position, thus simplifying the structure. 
     In addition, after the first and second links are extended to lift the hood, the first link stopper prevents the first link from inclining toward a rear of the vehicle. Accordingly, the lifted hood is supported not to move toward the rear of the vehicle by the first link thus preventing the hood at its rear end from nearing the front windshield by a required amount or more. In this manner, the mere provision of the first link stopper can prevent the hood rear end from nearing the front windshield by a required amount or more, thus simplifying the structure. 
     Meanwhile, the first and second link stopper can be integrally formed with the first and second links or bracket, thus simplifying forming and hence shortening forming time. In addition, because the first and second link stoppers are integrally formed with the first and second links or bracket, the assembling of the first and second link stoppers can be eliminated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Certain preferred embodiments of the present invention will be explained in detail below, by way of example only, with reference to the accompanying drawings, in which: 
     FIG. 1 is a side view of a vehicle carrying a vehicular hood device according to a first embodiment of the present invention; 
     FIG. 2 is a side view of the vehicular hood device according to the first embodiment; 
     FIG. 3 is an exploded perspective view showing hinge means forming part of the vehicular hood device according to the first embodiment; 
     FIGS. 4A and 4B are sectional views of the vehicular hood device according to the first embodiment; 
     FIGS. 5A,  5 B and  5 C are schematic side views illustrating procedures for assembling the hood device according to the first embodiment; 
     FIGS. 6A and 6B are schematic views illustrating an operation of the vehicular hood device according to the first embodiment, with the stopper pin cut to cause first and second links to swing; 
     FIG. 7 is a schematic side view illustrating an operation of the vehicular hood device according to the first embodiment, with the first and second links extended to hold the hood stationary at its upper limit position; 
     FIG. 8 is a schematic side view showing an operation of the vehicular hood device according to the first embodiment, with an obstacle falling onto the hood at its upper limit position; 
     FIGS. 9A and 9B are schematic side views showing an operation of the vehicular hood device of the first embodiment, with the hood opened about a hinge pin as an axis at a rear end thereof; 
     FIGS. 10A and 10B are schematic side views illustrating an operation of the vehicular hood device of the first embodiment, with the hood fully opened and the first and second opening prevention stoppers abutted against each other; 
     FIG. 11 is a schematic perspective view showing an operation of the vehicular hood device of the first embodiment, with the hood opened and abutted against the first and second opening preventing stoppers; 
     FIG. 12 is a perspective view showing a vehicular hood device according to a second embodiment of the present invention; 
     FIG. 13 is a perspective view showing a vehicular hood device according to a third embodiment of the present invention; 
     FIG. 14 is a side view showing a vehicle employing a vehicular hood device according to a fourth embodiment of the present invention; 
     FIG. 15 is a side view of the vehicular hood device according to the fourth embodiment of the present invention; 
     FIG. 16 is an exploded perspective view showing hinge means forming part of the vehicular hood device according to the fourth embodiment of the present invention; 
     FIG. 17 is a sectional view taken along line  17 — 17  in FIG. 15; 
     FIGS. 18A and 18B are schematic side views showing an operation of the vehicular hood device according to the fourth embodiment, with the hood opened about the hinge pin as an axis at a rear end side thereof to its full open position and abutted against the first and second opening-prevention stoppers; 
     FIGS. 19A and 19B are schematic side views showing an operation of the vehicular hood device according to the fourth embodiment, with a stopper pawl disengaged from a stopper hole to cause the first and second links to swing; 
     FIGS. 20A and 20B are schematic side views showing an operation of the vehicular hood device according to the fourth embodiment, with the first and second links swung to thereby extend the first and second links to hold the hood stationary at the upper limit position; 
     FIG. 21 is a schematic side view showing an operation of the vehicular hood device according to the fourth embodiment, with an obstacle falling onto the hood placed at the upper limit position; 
     FIG. 22 is a schematic side view showing an operation of the vehicular hood device according to the fourth embodiment, the vehicle hitting an obstacle with the hood held stationary at its upper limit position; 
     FIG. 23 is a schematic side view showing an operation of the vehicular hood device of the fourth embodiment, with the second link inclined toward the rear of the vehicle about a coupling pin as an axis; 
     FIG. 24 is a schematic side view illustrating an operation of the vehicular hood device according to the fourth embodiment, with the hood bent at its center and deformed into a hill-shape as a result of collision of the vehicle with an obstacle; 
     FIG. 25 is a side view showing a conventional vehicular hood device; 
     FIG. 26 is a side view showing an operation of the conventional vehicular hood device; and 
     FIGS. 27A,  27 B and  27 C are schematic views showing an operation of an actuator forming part of the conventional vehicular hood device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. 
     Referring to FIG. 1, a vehicle  10  employs a vehicular hood device  20  according to a first embodiment of the present invention. The vehicle  10  comprises an engine compartment  14  defined between right and left front fenders  12  (only left one shown) and a vehicular hood device  20  positioned upwardly of the engine compartment  14  and forwardly of a windshield  16  for impact absorption. 
     The vehicular hood device  20  is designed to lift a hood  21  at the front of the vehicle up to a position shown by an imaginary line and hold the hood  21  at the lift-up position when the vehicle  10  collides with an obstacle  18 . Hereunder, the vehicular hood device  20  will be described concretely. 
     The vehicular hood device  20  comprises a hood  21  of a front-opening type closing an upper aperture of the engine compartment  14 , left and right actuators  24  (only the left shown) for lifting the hood  21  at its left and right rear ends up to the position shown by the imaginary line, a bumper sensor  26  for detecting a collision of the vehicle  10  against the obstacle  18 , a control section  29  for delivering a drive signal to the actuator  24  on the basis of a detection signal from the sensor  26 , and left and right hinges (hinge means)  30  (only the left shown) supporting the hood  21  at its left and right rear ends to hold it in the lift-up position shown by the imaginary line. 
     Incidentally, the actuators  24  are the common parts to the left and right while the hinge means  30  are also common in the left and right. Hereinafter, description is only on the actuator  24  and the hinge means  30  that are on the left side, omitting the description on the right actuator  24  and hinge means  30 . 
     The hood  21  is structured to open at the front about a rear hinge pin as fulcrum, in order for repair and inspection, for example, in the engine compartment  14 . A hood lock  22  is attached at a front to lock the hood  21  to a vehicle frame  17 . 
     The actuator  24 , mounted on the vehicle frame  17 , is to ignite a gas-producing agent of an inflator thereby producing a gas. With the gas, the rod  25  is raised to lift the hood  21  by the rod  25  up to the position of the imaginary line. 
     FIG. 2 shows the hinge means  30  of the first embodiment of the invention, as viewed from the side thereof. The hinge means  30  is structured with a lower bracket  31  attached to the vehicle frame  17  and an upper bracket  41  attached at the rear end of the hood  21 , thereby bridging a first link  50  and second link  60  between the upper bracket  41  and the lower bracket  31 . 
     The hinge means  30  will be described in detail below. In the hinge means  30 , the first link  50  at a lower end  50   a  is attached swingably to the lower bracket  31  through a pin  55 . The second link  60  at a lower end  60   a  is attached swingably to an upper end  50   b  of the first link  50  through a couple pin  66 . The second link  60  at an upper end  60   b  is attached to the upper bracket  41  through a hinge pin  68 . 
     In the hinge means  30 , in a usual situation a rest portion  64  of the second link  60  is rested on a first stopper  38   a  of the lower bracket  31  (i.e. in the state the first link  50  and the second link  60  are folded). The hood  21  is opened and closed about the hinge pin  68  as a hinge center connecting between the second link  60  and the hood  21 . In the event of a collision of the vehicle  10  against an obstacle  18  shown in FIG. 1, the hood  21  is lifted by the action of the actuator  24  wherein a lift position of the hood  21  is determined by the extended first and second links  50 ,  60 . Thus, the hinge serves also as a couple-link mechanism. 
     In addition, the hinge means  30  upon operation of the actuator  24  allows the first and the second links  50 ,  60  to extend, but in a usual situation provides mechanical coupling to suppress the first and second links  50 ,  60  from extending. Meanwhile, a stopper mechanism  45  is provided between the hood  21  (specifically, the upper bracket  41 ) and the lower bracket  31  to prevent the hood from opening further in the case where the hood  21  in a usual situation opens a constant angle. 
     The stopper mechanism  45  comprises a first opening-prevention stopper  38   a  provided on the lower bracket  31  and a second opening-prevention stopper  44  provided on the upper bracket  41 . 
     FIG. 3 shows a disassembled state of the hinge means  30  of a first embodiment according to the invention. The lower bracket  31  of the hinge means  30  comprises a seat  33  for mounting to the vehicle frame  17  (shown in FIG. 2) through bolts  32 ,  32  (only one shown), a first bend portion  34  obliquely upwardly extending toward an outside direction of the frame  17  from the seat  33 , a second bend portion  35  vertically raised from the first bend portion  34 , a third bend portion  36  obliquely upwardly extending toward an inside direction of the vehicle frame  17  from the second bend portion.  35 , a fourth bend portion  37  generally in a trapezoidal form vertically raised from the third bend portion  36 , a first opening-prevention stopper  38   a  upwardly extending from an upper end of the fourth bend portion  37  and bent toward an inner side of the vehicular body, a stopper  38   b  adjacent the first opening-prevention stopper  38   a  and a protuberance  39  upwardly projecting from a slant portion of the fourth bend portion  37 . 
     In addition, the lower bracket  31  has a hole  37   a  in the fourth bend portion  37  to insert a pin  55  therein and a stopper hole  39   a  in the protuberance  39  to insert a stopper pin  40  therein. 
     The upper bracket  41  is a member formed generally in an L form in order for mounting to a back surface of the hood  21  (shown in FIG. 2) through bolts  42 ,  42 . This has a hole  43   a  formed at the rear of a vertical portion  43  to insert a hinge pin  68  and a second opening-prevention stopper  44  formed by bending in the vicinity of the hole  43   a.    
     The first link  50 , a member formed generally in an L form (see also FIG.  2 ), has a lower hole in a lower end  50   a  having a pin  55  inserted therein and a stopper  53 , and an upper hole in an upper end  50   b  having a coupling pin  66  inserted therein. 
     The second link  60 , a member formed generally in an L form (see also FIG.  2 ), has a lower hole  61   a  opened in a lower end  60   a  to insert the coupling pin  66  therein, a stopper hole  63  opened in the vicinity of the lower hole  61   a  to insert the stopper pin  40  therein, a stopper  62  provided in the vicinity of the lower hole  61   a , an upper hole  61   b  opened in an upper end  60   b  to insert the hinge pin  68  therein, and a rest portion  64  provided in the vicinity of the upper hole  61   b  to be rested upon the first opening-prevention stopper  38   a  of the lower bracket  31 . 
     Incidentally, the roles of the first and second opening-prevention stoppers  38   a ,  44  and the other stoppers  38   b ,  53 ,  62  will be explained in detail in FIG. 5 to FIG.  9 . 
     Next, one example of an assembling procedure of the hinge means  30  is explained with reference to FIG.  3 . First, the pin  55  is inserted in the lower hole of the first link  50 . This pin  55  is inserted and crimped in the hole  37   a  of the lower bracket  31 . This attaches the first link  50  for swing to the lower bracket  31 . 
     Next, the hinge pin  68  is inserted in the hole  43   a  of the upper bracket  41 . The hinge pin  68  is inserted and crimped in the upper hole  61   b  of the second link  60 . This attaches the second link  60  for swing to the upper bracket  41 . 
     Next, the first link  50  and the second link  60  are coupled together by the coupling pin  66  and then the coupling pin  66  is crimped. This couples the first link  50  and the second link  60 , for swing relative to each other. Subsequently, the stopper pin  40  is inserted in the stopper hole  39   a  of the lower bracket  31  and stopper hole  63  of the second link  60  and then the stopper pin  40  is crimped. This connects the second link  60  to the lower bracket  31  through the stopper pin  40 . 
     In the state where the first and second link  50 ,  60  and the upper bracket  41  are assembled on the lower bracket  31  in this manner, the lower bracket  31  is mounted to the vehicle frame  17  (shown in FIG. 2) by bolts  32 ,  32 . 
     Finally, the upper bracket  41  is attached to the hood  21  (shown in FIG. 2) by bolts  42 ,  42 . This completes the assembling of the hinge means  30 . 
     The hinge means  30 , in a folded state of the first and second links  50 ,  60  shown in FIG. 2, can be positioned in a state that the rest portion  64  of the second link  60  is rested on the first opening-prevention stopper  38   a  of the lower bracket  31 . This restricts the second link  60  from moving downward by the first opening-prevention stopper  38   a , making possible to support the hood  21  in a stable state. 
     The hinge means  30  has a stopper pin  40  to connect the second link  60  to the lower bracket  31  in the state the first and second links  50 ,  60  are folded, as shown in FIG.  2 . The stopper pin  40  has a strength which allows it to be cut when the actuator  24  operates but not to be cut by the usual hood opening/closing force, in order to prevent the hood  21  from being floated up. 
     In the hinge means  30 , by forming the first and second links  50 ,  60  shown in FIG. 2 each generally in an L form, the second link  60  can be attached along the slant portion  31   a  of the lower bracket  31  and the first link  50  be attached distantly from the slant portions  31   a . This can secure a site to have the stopper pin  40  in the vicinity of the slant portion  31   a.    
     Furthermore, in the hinge means  30 , by arranging the second link  60  along the slant portion  31   a  of the lower link  31  as shown in FIG. 2, the second link  60  can be inclined downward in a forward direction of the vehicle. Due to this, the lower bracket  31  at its pin  55  attaching position can be set in a comparatively high position with respect to the vehicle frame  17  (shown in FIG.  2 ). 
     Due to this, the form of the lower bracket  31  can be determined such that the hood  21  is ready to be crushed in the event an obstacle hits against the same. Incidentally, the form of the lower bracket  31  will be explained in detail in FIG.  4 . 
     FIG. 4A shows a section on line  4 ( a )— 4 ( a ) in FIG. 2 while FIG. 4B shows a section on line  4 ( b )— 4 ( b ) in FIG.  2 . FIG. 4A shows a state that the first link  50  is attached to the fourth bend portion  37  of the lower bracket  31  by the pin  55  and the second link  60  is on the upper bracket  41  by the hinge pin  68 . 
     The lower bracket  31  is a member formed, for example, of a soft steel bent generally in an inverted squared-U form having a second bend portion  35 , a third bend portion  36  and a fourth bend portion  37  that is a form ready to be crushed. Due to this, when the lower bracket  31  is applied by a load from the above, it is possible to absorb an impact by crushing the second bend portion  35 , third bend portion  36  and fourth bend portion  37 . 
     FIG. 4B shows a state that the stopper pin  40  is inserted in the stopper hole  39   a  of the lower bracket  31  and stopper hole  63  of the second link  60  and the stopper pin  40  is crimped. The stopper pin  40  has a strength that allows it to be cut when the actuator  24  (shown in FIG. 2) operates but not to be cut with the usual hood opening/closing force. 
     Accordingly, in the usual time where the second link  60  is connected to the lower bracket  31  by the stopper pin  40  thereby providing mechanical coupling to suppress the first and second links  50 ,  60  from extending, the hood  21  in the usual situation can be prevented from being floated up. 
     The mere provision of the stopper pin  40  makes it possible to prevent against chattering due, for example, to float-up of the hood  21  during traveling of the vehicle, thus reducing the number of parts. 
     Meanwhile, the stopper pin  40  upon operation of the actuator  24  (shown in FIG. 2) is cut by a lift-up force of the actuator  24  to release the state where the second link  60  is connected to the lower bracket  31 . Accordingly, it is possible to omit the operation mechanism for unlocking of the prior art. This can further reduce the number of parts. 
     FIGS. 5A to  5 C show a procedure for assembling the stopper pin  40  of the first embodiment. In FIG. 5A, the stopper pin  40  is inserted in the stopper hole  39   a  of the lower bracket  31  and stopper hole  63  of the second link  60 , as indicated by an arrow. In FIG. 5B, the stopper pin  40  at its head and tip is clamped by a crimp device  80  and a load is applied as indicated by open arrows, to crush the tip of the stopper pin  40 . In FIG. 5C, the stopper pin  40  is prevented at a crushed portion  40   c  of the stopper pin  40  from being removed. 
     Herein, the stopper pin  40  is formed with a larger diameter portion  40   a  and a smaller diameter portion  40   b , to be readily cut at a step  40   d . With this stopper pin  40 , the larger diameter portion  40   a  is inserted in the stopper hole  39   a  and the smaller diameter portion  40   b  in the stopper hole  63 , thereby placing the step  40   d  at the boundary between the lower bracket  31  and the second link  60 . Accordingly, when the actuator  24  is operated, the stopper pin  40  can be positively cut at the step  40   d.    
     Next, the operation of the vehicular hood device  20  of the first embodiment is explained on the basis of FIG. 1, FIG.  4  and FIG. 6 to FIG.  11 . 
     First, explanation is made for the case where the vehicle collides against an obstacle. Referring back to FIG. 1, if the vehicle  10  in traveling collides against an obstacle  18 , the bumper sensor  26  detects a collision to transmit a detection signal from the bumper sensor  26  to the control section  29 . The control section  29  transmits a drive signal to the actuator  24  so that a gas pressure is exerted on the actuator  24  to project the rod  25 . By the gas pressure acted upon the rod  25  of the actuator  24 , the rod  25  is instantaneously raised by the gas pressure to apply a lift-up force F 1  to the hood  21  as shown by the arrow. 
     Next, by applying a lift force F 1  to the hood  21  as shown in FIG. 4B, a force F 2  acts to lift up the smaller diameter portion  40   b  of the stopper pin  40  through the upper bracket  41 , hinge pin  68  (shown in FIG. 4A) and stopper hole  63  of the second link  60 . Due to this, the stopper pin  40  is cut at its step  40   d.    
     In FIG. 6A, due to cutting of the stopper pin  40 , the second link  60  swings counterclockwise about the coupling pin  66  as an axis. Simultaneously, the first link  50  swings clockwise about the pin  55  as an axis. 
     Consequently, by a start of extension of the first and second links  50 ,  60 , the hood  21  is raised as shown at an arrow ( 1 ) about a hood lock mechanism  22  (shown in FIG. 1) as an axis. FIG. 6B is a sectional view on line b—b in FIG.  6 A. As shown in FIG. 6B, the stopper pin  40  is cut at the step  40   d.    
     In FIG. 7, the first and second links  50 ,  60  extend to position the pin  55 , the coupling pin  66  and the hinge pin  68  on a straight line  70 . Due to this, the first and second links  50 ,  60  restrict the hood  21  from rising thus positioning the hood  21  stationary at an upper limit position P 1 . 
     The weight of the hood  21 , after halt, acts to descend the hood  21 . Consequently, the weight of the hood  21  acts upon the first and second links  50 ,  60  to fold the first and second links  50 ,  60 . 
     However, because the pin  55 , the coupling pin  66  and the hinge pin  68  are positioned on the straight line  70 , the first and second links  50 ,  60  even applied by the weight of the hood  21  will not be folded. For this reason, the hood  21  can be held by the first and second links  50 ,  60 . 
     In this state, an obstacle  18  falls on the hood  21  thereby applying an external force F 3  as shown at an arrow. This applies a force to incline the first link  50  rearward of the vehicle about the pin  55  as an axis. However, the first link  50  can be prevented from inclining toward the rear of the vehicle by abutting the stopper  53  of the first link  50  against the stopper  38   b  of the lower bracket  31 . 
     Simultaneously, a force is applied to incline the second link  50  forward of the vehicle about the coupling pin  66  as an axis. However, the second link  60  can be prevented from inclining toward the forward of the vehicle by abutting the stopper  62  of the second link  60  against the first link  50 . 
     Accordingly, because the first and second links  50 ,  60  can be kept in an extension state, the hood  21  can be held at the upper limit position P 1  where it is lifted by a predetermined amount by the hinge means  30 . 
     In FIG. 8, by lifting the hood  21  by a predetermined amount from a position shown at an imaginary line to a position shown at a solid line, it is possible to increase the distance from the hood  21  to an apparatus  19  such as an engine accommodated in the engine compartment  14 . Accordingly, the hood  21  can secure its downward deformation amount sufficiently. 
     Consequently, in the event that the obstacle  18  falls onto the hood  21  to apply an external force F 3  as shown at the arrow, it is possible to secure broad a dent  21   a  in the hood  21  as shown by an imaginary line. Accordingly, the impact exerted to the obstacle  18  can be absorbed positively. 
     In addition, as shown in FIG. 4A the lower bracket  31  at the second bend portion  35 , third bend portion  36  and fourth bend portion  37  is bent generally in an inverted squared-U form that is a form ready to be crushed. Accordingly, when the obstacle  18  falls onto the hood  21  to apply an external force F 3  as shown at the arrow, the second bend portion  35 , third bend portion  36  and forth bend portion  37  can be crushed to absorb an impact. Thus, the impact exerted to the obstacle  18  can be absorbed more positively. 
     Meanwhile, if the dent amount of the dent  21   a  caused in the hood  21  is increased as shown at an imaginary line, the dent  21   a  will not interfere with the engine compartment apparatus  19 . Thus, the apparatus  19  can be protected from the obstacle  18 . 
     Next, explained is an example of opening the hood  21  in order for maintenance and inspection of the engine compartment. 
     In FIGS. 9A and 9B, the rest portion  64  of the second link  60  is rested on the first opening-prevention stopper  38   a  of the lower bracket  31 , and then the stopper pin  40  is inserted in the stopper hole  39   a  of the lower bracket  31  and stopper hole  63  of the second link  60  shown in FIG.  4 B. Due to this, the first and second links  50 ,  60  are kept in a folded state. In this state, the hood lock mechanism  22  (shown in FIG. 1) in front of the hood  21  is released to open the hood  21  as shown at the arrow ( 2 ) about as an axis the hinge pin  68  on the rear end side of the hood  21 . 
     In FIGS. 10A and 10B, by opening the hood  21  up to a full-open position, the second opening-prevention stopper  44  of the upper bracket  41  abuts against the first opening-prevention stopper  38   a  of the lower bracket  31 , thereby restricting the hood  21  from further opening. 
     By opening the hood  21 , maintenance and inspection can be made from the above for the apparatus in the engine compartment. 
     Incidentally, when the second opening-prevention stopper  44  abuts against the first opening-prevention stopper  38   a  due to opening the hood  21 , such a force acts that rotates the second link  60  clockwise about the hinge pin  68  as an axis. However, the second link  60  can be kept in a stationary state by resting the rest portion  64  on the first open-prevention stopper  38   a  of the lower bracket  31  and inserting the stopper pin  40  in the stopper holes  39   a ,  63 . 
     By the provision of the second opening-prevention stopper  44  on the upper bracket  41  and the first opening-prevention stopper  38   a  on the lower bracket  31 , when the hood  21  is opened by a constant angle in a usual situation, the parts constituting a stopper mechanism  45  come into abutment, i.e. the second opening-prevention stopper  44  abuts against the first opening-prevention stopper  38   a  thereby preventing the hood  21  from further opening. 
     The hood  21  can be prevented from opening to a constant angle or greater by merely providing the stopper mechanism  45  (second opening-prevention stopper  44  and first opening-prevention stopper  38   a ) to abut the second opening-prevention stopper  44  against the first opening-prevention stopper  38   a.    
     Because the hood  21  can be prevented from opening to a constant angle or greater by the structure merely provided with the second opening-prevention stopper  44  and first opening-prevention stopper  38   a , the hinge mechanism  30  of the vehicular hood device  20  can be simplified in structure. Hence, the device can be reduced in size and weight. 
     FIG. 11 shows a state where the hood  21  of the first embodiment is opened. A second opening-prevention stopper  44  is formed by bending the upper bracket  41  at its vertical portion  43  while a first opening-prevention stopper  38   a  is formed by bending a lower bracket  31  at its fourth bending portion  37 . 
     Accordingly, it is possible to secure the contact area between the second opening-prevention stopper  44  and the first opening-prevention stopper  38   a , i.e. of the stopper mechanism  45 . Hence, the hood  21  can be positively restricted from opening. 
     Incidentally, because the above can be formed by merely bending the second opening-prevention stopper  44  and first opening-prevention stopper  38   a , it is possible to further simplify the structure of the second opening-prevention stopper  44  and first opening-prevention stopper  38   a.    
     Next, second to fourth embodiments are explained. It is noted that the same members as the members of the first embodiment of vehicular hood device are denoted by the same reference numerals and detailed explanations thereof are omitted. 
     Second Embodiment 
     FIG. 12 shows a vehicular hood device  80  of a second embodiment according to the invention. The vehicular hood device  80  of the second embodiment has hinge means  81 . The hinge means  81  has a stopper mechanism  84  comprising a first opening-prevention stopper  83  and a second opening-prevention stopper  44 , by forming the first opening-prevention stopper  83  of a lower bracket  82  without bending the lower bracket  82 . It is noted that other structures are the same as those of the first-embodiment hinge means  30 . 
     The second embodiment provides the effects similar to those of the first embodiment. In addition, because the first opening-prevention stopper  83  is formed not by bending the lower bracket  82 , it is possible to omit the labor and time for bending the lower bracket  82 . Accordingly, the lower bracket  82  is simplified in forming thereby further enhancing the producibility. 
     Third Embodiment 
     FIG. 13 shows a vehicular hood device  90  of a third embodiment according to the invention. The vehicular hood device  90  of the third embodiment has hinge means  91 . The hinge means  91  has a stopper mechanism  94  comprising a first opening-prevention stopper  38   a  and a second opening-prevention stopper  93 , by forming the second opening-prevention stopper  93  of an upper bracket  92  without bending the upper bracket  92 . It is noted that other structures are the same as those of the first-embodiment hinge means  30 . 
     The third embodiment provides the effects similar to those of the first embodiment. In addition, because the second opening-prevention stopper  93  is formed not by bending the upper bracket  92 , it is possible to omit the labor and time for bending the upper bracket  92 . Accordingly, the upper bracket  92  is simplified in forming thereby further enhancing the producibility. 
     Fourth Embodiment 
     FIG. 14 shows a vehicle  110  mounted thereon with a vehicular hood device  120  of a fourth embodiment according to the present invention. The vehicle  110  shown in FIG. 14 has an engine compartment  14  formed between the front fenders  12  on the left and right (only the left shown), and a vehicular hood device  120  for impact absorption is arranged above the engine compartment  14  and in front of the front windshield  16 . 
     The vehicular hood device  120  is to lift a hood  21  at the front of the vehicle up to a position shown at the imaginary line and hold the hood  21  at the lift-up position when the vehicle  110  collides against an obstacle  18 . Hereunder, the vehicular hood device  120  will be described concretely. 
     The vehicular hood device  120  comprises the hood  21  of a front-opening type closing an upper aperture of the engine compartment  14 , left and right actuators  24  (only the left shown) for lifting the hood  21  at its left and right rear ends thereof up to the position shown at the imaginary line, a bumper sensor  26  for detecting a collision of the vehicle  110  against the obstacle  18 , a control section  29  for delivering a drive signal to the actuators  24  on the basis of a detection signal from the sensor  26 , and left and right hinges (hinge means)  130  (only the left shown) supporting the hood  21  at its left and right rear ends to hold it in the lift-up position shown at the imaginary line. 
     Incidentally, the actuators  24  are the common parts to the left and right while the hinge means  130  are also common to the left and right. Hereinafter, description is only on the actuator  24  and the hinge means  130  that are on the left side, omitting the description on the right actuator  24  and hinge means  130 . 
     The hood  21  is structured to open at the front about rear hinge pins as fulcrums, in order for repair and inspection, for example, in the engine compartment  14 . A hood lock  22  is attached at a front to lock the hood  21  to a vehicle frame  17 . 
     The actuator  24 , mounted on the vehicle frame  17 , is to ignite a gas-producing agent of an inflator thereby producing a gas. With the gas, the rod  25  is raised to lift the hood  21  by the rod  25  up to the position of the imaginary line. 
     FIG. 15 shows the vehicular hood device  120  of the fourth embodiment of the invention, as viewed from the side thereof. The hinge means  130  of the vehicular hood device  120  is structured with a lower bracket  131  attached to the vehicle frame  17  and an upper bracket  141  attached at the rear end of the hood  21 , thereby bridging a first link  150  and second link  160  between the upper bracket  141  and the lower bracket  131 . 
     Hereunder, the hinge means  130  will be described concretely. In the hinge means  130 , the first link  150  at a lower end  150   a  is attached swingably to the lower bracket  131  through a pin  155 . The second link  160  at a lower end  160   a  is attached swingably to an upper end  150   b  of the first link  150  through a couple pin  166 . The second link  160  at an upper end  160   b  is attached to the upper bracket  141  through a hinge pin  168 . 
     In the hinge means  130 , in a usual situation a rest portion  164  of the second link  160  is rested on a first stopper  138  of the lower bracket  131  (i.e. in the state the first link  150  and the second link  160  are folded). The hood  21  is opened and closed about the hinge pin  168  as a hinge center connecting between the second link  160  and the hood  21 . In the event of a collision of the vehicle  110  against an obstacle  18  shown in FIG. 14, the hood  21  is lifted by the action of the actuator  24  wherein a lift position of the hood  21  is determined by the extended first and second links  150 ,  160 . Thus, the hinge serves also as a couple-link mechanism. 
     In addition, the hinge means  130  has, on the first link  150 , a first link stopper  153  to prevent the first link  150  from inclining rearward of the vehicle after extension of the first and second links  150 ,  160  by the action of the actuator  24  and, on the second link  160 , a second link stopper  162  to engage the second link  160  with the first link  150  upon inclining of the second link  160  frontward of the vehicle. 
     FIG. 16 shows the hinge means  130  of the fourth embodiment according to the invention, in an exploded perspective state. The lower bracket  131  of the hinge means  130  comprises a seat  133  for mounting to the vehicle frame  17  (shown in FIG. 15) through bolts  132 ,  132  (only one shown), a first bend portion  134  obliquely upwardly extending toward an outside direction of the vehicle frame  17  from the seat  133 , a second bend portion  135  vertically raised from the first bend portion  134 , a third bend portion  136  obliquely upwardly extending toward an inside direction of the vehicle frame  17  from the second bend portion  135 , a fourth bend portion  137  generally in a trapezoidal form vertically raised from the third bend portion  136 , a first stopper  138  upwardly extending from an upper end of the fourth bend portion  137  and bent toward an inner side of the vehicular body, a second stopper  139  adjacent the first stopper  138  and a stopper pawl  140  upwardly extending from a top end of the fourth bend portion  137  and bent toward the inner side of the vehicle frame  17 . 
     The fourth bend portion  137  has a hole  137   a  for insertion of a pin  155 . 
     The upper bracket  41  is a member formed generally in an L form in order for mounting onto a back surface of the hood  121  (shown in FIG. 15) through bolts  142 ,  142 . This has a hole  143   a  formed at the rear of a vertical portion  143  to insert a hinge pin  168  and a second opening-prevention stopper  144  formed by bending in the vicinity of the hole  143   a.    
     The first link  150  is a member formed generally in an L form as shown in FIG.  15 . This has a lower hole in a lower end  150   a  to insert a pin  155 , a link stopper  153 , and an upper hole in an upper end  150   b  to insert a coupling pin  166 . 
     The second link  160  is a member formed generally in an L form as shown in FIG.  15 . This has a lower hole  161   a  opened in a lower end  160   a  to insert the coupling pin  166 . A second link stopper  162  is provided in the vicinity of the lower hole  161   a , while an upper hole  161   b  is opened in an upper end  160   b  to insert the hinge pin  168 . A stopper hole  163  is opened in the vicinity of the upper hole  161   b  to insert a stopper pawl  140 . A rest portion  164  is provided in the vicinity of the stopper hole  163  to rest on the first stopper  138  of the lower bracket  131 . 
     Incidentally, the roles of stoppers  138 ,  139 ,  144  and first and second link stoppers  153 ,  162  will be explained in detail in FIG. 18 to FIG.  26 . 
     Next, one example of an assembling procedure of the hinge means  130  is explained with reference to FIG.  16 . First, the lower bracket  131  is mounted to the vehicle frame  17  (shown in FIG. 15) by bolts  132 ,  132 . The pin  155  is inserted in the lower hole of the first link  150 . This pin  155  is inserted and crimped in the hole  137   a  of the lower bracket  131 . This attaches the first link  150  for swinging with respect to the lower bracket  131 . 
     Next, the hinge pin  168  is inserted in the hole  143   a  of the upper bracket  141 . The hinge pin  168  is inserted and crimped in the upper hole  161   b  of the second link  160 . This attaches the second link  160  for swinging with respect to the upper bracket  141 . 
     Next, the stopper pawl  140  is inserted in the stopper hole  163  of the second link  160 . The first link  150  and the second link  160  are coupled together by the coupling pin  166  and then the coupling pin  166  is crimped. This couples the first link  150  and the second link  160 , for swinging relative to each other, and the second link  160  is connected to the lower bracket  131  by the stopper pawl  140 . 
     In the state where the first and second link  150 ,  160  and the upper bracket  141  are assembled on the lower bracket  131  in this manner, the lower bracket  131  is mounted to the vehicle frame  17  (shown in FIG. 2) by bolts  132 ,  132 . 
     Finally, the upper bracket  141  is attached to the hood  21  (shown in FIG. 15) by bolts  142 ,  142 . This completes the assembling of the hinge means  30  of FIG. 15, i.e. the state in which the first and second links  150 ,  160  are folded. 
     The hinge means  130 , in a folded state of the first and second links  150 ,  160  as shown in FIG. 15, can be positioned such that the rest portion  164  of the second link  160  is rested on the first stopper  138  of the lower bracket  131 . This restricts the second link  160  from moving downward by the first stopper  138 , thereby making it possible to support the hood  21  in a stable state. 
     Also, the hinge means  130  has a stopper pawl  140  in the lower bracket  131  to connect (engage) the second link  160  to the lower bracket  131  in the state in which the first and second links  150 ,  160  are folded, as shown in FIG.  15 . The stopper pawl  140  is released from coupling and disengaged from the second link  160  when the actuator  24  is operated but has rigidity maintaining the coupled state with a usual hood opening/closing force, thus preventing the hood  21  from being floated in a usual situation. 
     Furthermore, by arranging the second link  160  along the slant portion  131   a  of the lower bracket  131  as shown in FIG. 15, the second link  160  can be inclined downward in a forward direction of the vehicle. Due to this, the lower bracket  131  at its pin  155  attaching position can be set in a comparatively high position with respect to the vehicle frame  17  (shown in FIG.  15 ). 
     Due to this, the form of the lower bracket  131  can be determined such that the hood  21  is ready to be crushed in the event an obstacle hits against the same. Incidentally, the form of the lower bracket  131  will be explained in detail in FIG.  17 . 
     FIG. 17 shows a section on line  17 — 17  in FIG.  15 . As shown in the figure, the lower bracket  131  is a member formed, for example, a mild steel having a second bend portion  135 , a third bend portion  136  and a fourth bend portion  137  that is bent generally in a squared-U form that is ready to be crushed. Consequently, when the lower bracket  131  is loaded from above, impact can be absorbed due to crushing the second bend portion  135 , the third bend portion  136  and the fourth bend portion  137 . 
     Also, shown is a state where the first link  150  is attached to the forth bend portion  137  of the lower bracket  131  through the pin  155 , the stopper pawl  140  of the lower bracket  131  is inserted in the stopper hole  163  of the second link  160 , and the second link  160  is attached to the upper bracket  141  by the hinge pin  168 . 
     The stopper pawl  140  is a member formed of a mild steel similar to the lower bracket  131 . This is a member having rigidity set such that it can keep a coupled state of inserted in the stopper hole  163  during usual force opening/closing the hood or usual vehicle traveling but is deformed for disengagement from the stopper hole  163  upon operation of the actuator  24 . 
     Due to this, by connecting the second link  160  to the lower bracket  131  by the stopper pawl  140 , i.e. inserting the stopper pawl  140  in the stopper hole  163 , the first and second links  150 ,  160  are prevented from extending and hence the hood  21  is prevented from being floated in the usual situation. 
     The mere provision of the stopper pawl  140  makes it possible to prevent against, for example, the chatter due to floating-up of the hood  21  during traveling of the vehicle. 
     On the other hand, the stopper pawl  140 , upon operation of the actuator  24  (shown in FIG.  15 ), is deformed by a lift force of the actuator  24  and disengaged from the stopper hole  163  of the second link  160 . Thus, it is possible to omit the prior-art operation mechanism for unlocking. This further reduces the number of parts. 
     Next, explanation is made of an example for opening the hood in order for repair and inspection in the engine compartment in the fourth embodiment shown in FIGS. 18A and 18B. In FIG. 18A, the stopper pawl  140  is inserted in the stopper hole  163  thereby keeping the first and second links  150 ,  160  in the folded state. In this state, the hood lock mechanism  22  (shown in FIG. 14) in front of the hood  21  is released to open the hood  21  about the hinge pin  168  as an axis at the rear of the hood  21 , as shown at an arrow ( 3 ). 
     In FIG. 18B, by opening the hood  21  up to its full open position, the stopper  144  of the upper bracket  141  abuts against the first stopper  138  of the lower bracket  131  thus restricting the hood  21  from opening. In this case, a force acts to rotate the second link  160  clockwise about the hinge pin  168  as an axis. However, the insertion of the stopper pawl  140  in the stopper hole  163  prevents the second link  160  from rotating. 
     The opening of the hood  21  allows for maintenance and inspection of the apparatus in the engine compartment from above. 
     Next, explanation is made on the action where the vehicle collides against an obstacle, with reference to FIG. 14, FIG.  17  and FIG. 19 to FIG.  21 . 
     Referring back to FIG. 14, when the vehicle  110  in traveling collides against the obstacle  18 , the bumper sensor  26  detects a collision so that the sensor  26  transmits a detection signal to the control section  29 . The control section  29  delivers a drive signal to the actuator  24  so that a gas pressure exerts on the actuator  24  to project the rod  25  therefrom. The action of gas pressure upon the rod  25  of the actuator  24  causes the rod  25  to instantaneously rise due to the gas pressure and applies a lift force F 1  to the hood  21  as shown at an arrow. 
     Next, by applying a lift force F 1  to the hood  21  as shown in FIG. 17, a lift-up force F 4  is applied to the stopper pawl  140  through the upper bracket  141 , hinge pin  168  and stopper hole  163  of second link  160 . 
     This deforms the stopper pawl  140  so as to expand and disengage from the stopper hole  163 . 
     In FIG. 19A, by the disengagement of the stopper pawl  140  from the stopper hole  163 , the second link  160  swings counterclockwise about the coupling pin  166  as an axis. Simultaneously, the first link  150  swings clockwise about the pin  155  as an axis. 
     Accordingly, by starting the extension of the first and second links  150 ,  160 , the hood  21  is lifted about the hood lock mechanism  22  (shown in FIG. 14) as an axis, as shown at an arrow ( 4 ). 
     FIG. 19B shows a section on line b—b in FIG.  19 A. In FIG. 19B, the stopper pawl  140  is deformed by expansion to the above, disengaging from the stopper hole  163 . 
     In FIG. 20A, the hood  21  is continuously lifted up as shown at an arrow ( 5 ) by a lift-up force F 1  of the rod  25  of the actuator  24 . The rise of the hinge pin  168  places the first and second links  150 ,  160  into a state of extension midway. 
     In FIG. 20B, by completely extending the first and second links  150 ,  160 , the pin  155 , the coupling pin  166  and the hinge pin  168  are positioned on a straight line  170 . Due to this, the hood  21  is restricted from rising by the first and second links  150 ,  160  to position the hood  21  stationary at an upper limit P 2  position. 
     After halting the hood  21 , the weight of the hood  21  acts to close the hood. Consequently, the weight of the hood  21  acts upon the first and second links  150 ,  160  in a manner folding the first and second links  150 ,  160 . 
     However, because of the pin  155 , the coupling pin  166  and the hinge pin  168  positioned on the straight line  170 , the first and second links  150 ,  160  will not be folded by the weight of the hood  21 . Thus, the hood  21  can be kept at the upper limit position P 2  by the first and second links  150 ,  160 . 
     In the state the hood  21  is held at the upper limit position P 2 , if the obstacle  18  falls onto the hood  21 , an external force F 3  acts upon it as shown at an arrow, thus causing a dent in the hood  21 . This pulls the rear end of the hood  21  toward the front of the vehicle, thereby applying an external force F 5  to the hinge pin  168  as shown at an arrow. Accordingly, the second link  160  is inclined toward the front of the vehicle about the coupling pin  166  as an axis, as shown at an arrow ( 6 ). 
     At this time, the second link stopper  162  of the second link  160  is abutted against the first link  150  thereby engaging the second link  160  with the first link  150 . Consequently, the second link  160  is prevented from inclining toward the front of the vehicle thereby holding the hood  21  at the upper limit position P 2 . 
     Meanwhile, where a force is applied to incline the first link  150  toward the rear of the vehicle about the pin  155  as an axis, the first link  150  can be prevented from inclining toward the rear of the vehicle by abutting the first link stopper  153  of the first link  150  against the second stopper  139  of the lower bracket  131 . 
     When the hood  21  is lifted by extending the first and second links  150 ,  160 , the pin  155 , the coupling pin  166  and the hinge pin  168  are positioned on the straight line  170  thereby preventing the first and second links  150 ,  160  from being folded by the weight of the hood  21 . 
     In addition, in the event the obstacle  18  falls onto the hood  21 , the second link stopper  162  prevents the second link  160  from inclining toward the front of the vehicle. Thus, the first and second links  150 ,  160  are prevented from being folded to hold the lifted hood  21  at the upper limit position P 2 . In this manner, the mere provision of the second link stopper  162  holds the hood  21  at a raised position thus simplifying the structure of the mechanism for holding the hood  21 . 
     Meanwhile, the first and second link stoppers  153 ,  162  can be integrally formed with the first and second links  150 ,  160 , thus simplifying the forming and shortening the forming time. In addition, because the first and second link stoppers  153 ,  162  are integrally formed with the first and second links  150 ,  160 , it is possible to eliminate the assembling of the first and second link stoppers  153 ,  162 . 
     As shown in FIG. 21, by lifting the hood  21  by a predetermined amount from a position shown at an imaginary line to a position shown at a solid line, it is possible to increase the distance from the hood  21  to the apparatus  19 , such as the engine, accommodated in the engine compartment  14 . Therefore, the hood  21  can be secured with a sufficient amount of downward deforming. 
     Consequently, even if the obstacle  18  falls onto the hood  21  to apply an external force F 3  as shown at the arrow, a dent region  21   a  can be secured broadly as shown at an imaginary line in the hood  21 . Hence, the impact exerted by the obstacle  18  can be absorbed positively. 
     In addition, as shown in FIG. 17 the lower bracket  131  at its second bend portion  135 , third bend portion  136  and fourth bend portion  137  is bent generally in a squared-U shape that is a form ready to be crushed. Accordingly, in the event that the obstacle  18  falls onto the hood  21  to apply an external force F 3  as shown at the arrow, the impact can be absorbed by crushing the second bend portion  135 , third bend portion  136  and fourth bend portion  137 . Hence, the impact exerted by the obstacle  18  can be absorbed further positively. 
     Meanwhile, if the amount of dent in the hood  21  is broadened as shown at the imaginary line, the dent  21   a  will not interfere with the apparatus  19  in the engine compartment thus protecting the apparatus  19  from the obstacle  18 . 
     Next, explanation is made of the action of the vehicular hood device  120  upon colliding of the vehicle  110  of the fourth embodiment against a wall or the like, with reference to FIG. 22 to FIG.  24 . 
     FIG. 22 shows that the vehicle  110  of the fourth embodiment collides against a comparatively solid obstacle  180  of a wall or the like. When the vehicle  110  collides against the obstacle  180 , the control section  29  transmits a drive signal to the actuator  24  on the basis of a detection signal of the bumper sensor  26  to lift a rear of the hood  21  by the actuator  24 . The first and second links  150 ,  160  extend to position the pin  155 , the coupling pin  166  and the hinge pin  168  on a straight line  170  (shown in FIG.  20 B). Consequently, the first and second links  150 ,  160  are prevented from being folded to hold the hood  21  at a lifted position. 
     At this time, the engine compartment  14  of the vehicle  110  is deformed to push the hood  21  toward the rear of the vehicle, causing a force F 6  to incline the second link  160  toward the rear of the vehicle about the coupling pin  166  as an axis. 
     In FIG. 23, the external force F 6  is applied to the second link  160  thereby inclining the second link  160  toward the rear of the vehicle about the coupling pin  166  as an axis. 
     Next, a force F 7  is applied to the coupling pin  166  to incline the first link  150  toward the rear of the vehicle about the pin  155  as an axis. At this time, because the first link stopper  153  of the first link  150  is in abutment against the second stopper  139  of the lower bracket  131 , the first link  150  can be prevented from inclining toward the rear of the vehicle. 
     Accordingly, it is possible to restrict a tip of the upper bracket  141  attached to the hood  21 , i.e. the stopper  144 , from moving toward the rear of the vehicle. Thus, the stopper  144  of the upper bracket  141  will not approach the front windshield  182  by a required amount or greater. 
     After extending the first and second links  150 ,  160 , the first link  150  is prevented by the first link stopper  153  from inclining toward the rear of the vehicle. Accordingly, the hood  21  while lifted is held so as not to move toward the rear of the vehicle by the first link  150  whereby the hood  21  at its rear end, i.e. the stopper  144  of the upper bracket  141 , can be prevented from moving toward the front windshield  182  by a required amount or greater. 
     In this manner, the mere provision of the first stopper  153  for abutment against the second stopper  139  of the lower bracket  131  can prevent the rear end of the hood  21  from moving toward the front windshield  182  by a required amount or greater. 
     In FIG. 24, by restricting the stopper  144  of the upper bracket  141  from moving toward the rear of the vehicle and by deformation of the engine compartment  14  in the vehicle  110 , the hood  21  at its center is raised and deformed into a mountain form. In this manner, when the vehicle  110  collides against the obstacle  180 , the engine compartment  14  or hood  21  deforms thereby absorbing an impact force due to collision. 
     Incidentally, although the foregoing first embodiment explained in the example as having the protuberance  39  in the inclination portion of the lower bracket  31  and a stopper pin  40  on the protuberance  39 , the arrangement position of the stopper pin  40  may be set arbitrarily. 
     Also, although the first embodiment explained in the example that the stopper pin  40  was inserted in the stopper hole  63  of the second link  60  as means for connecting the second link  60  to the lower bracket  31 , the stopper pin  40  may be inserted in both link stopper holes of the first link  50  and the second link  60 . 
     Furthermore, although the first embodiment explained in the example that the lower bracket  31 ,  131  was formed of a mild steel, the material is not limited to that. 
     The first opening-prevention stopper  38   a ,  83  and the second opening-prevention stopper  44 ,  93  explained in the first to third embodiment are not limited to the forms explained in the first to third embodiment but may be formed in other forms. 
     Meanwhile, although the fourth embodiment explained in the example that the first link stopper  153  was provided on the first link  150 , the first link stopper  153  is satisfactorily provided between the first link  150  and the lower bracket  131 . The first link stopper  153  may be provided on the lower bracket  131 . 
     Furthermore, although the fourth embodiment explained in the example that the second link stopper  162  was provided on the second link  160 , the second link stopper  162  is satisfactorily provided between the second link  160  and the first link  150 . The second link stopper  162  may be provided on the first link  150 . 
     Although, the fourth embodiment explained in the example that the stopper pawl  140  was formed in the upper end of the lower bracket  131 , the arrangement position of the stopper pawl  140  may be set arbitrarily. 
     Also, the fourth embodiment explained in the example that the stopper pawl  140  was inserted in the stopper hole  163  of the second link  160  as means for connecting the second link  160  to the lower bracket  131 . However, the stopper pawl  140  can engage an upper side of the second link  160  to connect the second link  160  to the lower bracket  131 . 
     Furthermore, in the fourth embodiment, the stopper pawl  140  may be inserted in both of the first link  150  and second link  160 . 
     Although the fourth embodiment explained in the example that the lower bracket  131  and the stopper pawl  140  are formed of a mild steel, the material is not limited to this. 
     Also although the first and fourth embodiments were explained in the examples as having the actuators  24  and hinge means  30 ,  130  arranged each two in number at the left/right side of the vehicle frame  17 , the actuators  24  and hinge means  30 ,  130  may be arranged only at one side of the vehicle frame  17 . This reduces the number of parts and further suppresses the mount-up of cost. 
     Furthermore, although the first and fourth embodiments arranged the actuators  24  on the vehicle frame  17 , the actuators  24  may be provided on the hood  21 . 
     Although the first and second embodiments explained in the examples that the hood  21  was lifted by the rod  25  of the actuator  24  until it reaches the upper limit position P 1 , P 2 , the hood  21  may jump up to the upper limit position P 1 , P 2  by the rod  25  of the actuator  24 . Because the stroke of the rod  25  can be decreased, the actuator  24  can be reduced in size. 
     Obviously, various minor changes and modifications of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.