Abstract:
The present invention discloses an anti-submarine seat for an automobile. The anti-submarine seat prevents the occupant pelvis from slipping forward during a collision. The present invention discloses installing spring-type actuator means at a lower portion of a seat cushion so as to raise a front end of the seat cushion and to descend the rear end of the seat cushion at the time of an impact.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a seat for an automobile. More particularly, the present invention relates to an anti-submarine seat for an automobile capable of preventing the pelvis of a user from sliding forward during a collision. 
     BACKGROUND OF THE INVENTION 
     There are many safety devices for the occupants of a vehicle, such as, seat belts, air bags, and the like. Typically the seat belt and the air bag are disposed between a passenger seat and a dashboard of the vehicle. The seat belt and the air bag function to restrain the upper body of the passenger during a collision such that injury to the passenger is potentially reduced. 
     However, a drawback associated with these devices is that the safety of the occupants is not entirely considered. For example, the so-called ‘submarine phenomenon’ occurs during many impacts, such as in vehicle collisions. This phenomenon is typified by the pelvis of an automobile occupant sliding forward, under a seat belt. This leads to injury in the leg region from collision with a lower end of a crash pad and to injury in the abdomen region from tension of the seat belt. 
     A submarine phenomenon preventing mechanism that raises the front end of the seat cushion is known in the art. However, the conventional submarine phenomenon preventing mechanism adversely effects the ergonomics of the automobile seat. Therefore, the occupant may be guarded from the submarine phenomenon injury, however they suffer from poor ergonomics, reduced comfort, and potential injury to the knees during long distance travel. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention provide an anti-submarine seat for an automobile that reduces the chance of the pelvis of an automobile occupant from slipping forward during a collision. By installing a spring-type actuator means at a lower portion of a seat cushion, so as to raise a front end of the seat cushion and to descend a rear end of the seat cushion, the submarine phenomenon is potentially reduced. 
     An anti-submarine seat for an automobile according to an embodiment of the present invention comprises a spring-type actuators for elastically supporting a front end and a rear end of the seat cushion of the automobile. The actuators being installed at a lower portion of the seat cushion. The actuators urge the front end of the seat cushion upwards and simultaneously descend the rear end of the seat cushion in case of an impact situation such as a vehicle crash. 
     The actuators include a cylindrical upper housing installed at an upper seat frame and a cylindrical lower housing installed at a lower seat frame. A spring and a spring seat are installed in the lower housing or in the upper housing. The spring and the spring seat are fixed in the lower housing or in the upper housing by means of a wedge-shaped spring fixing pin so that operation of the spring is selectively controlled. 
     In a preferred embodiment, the actuator is installed at the front end of the seat cushion and the spring is installed in the lower housing. In an alternative embodiment, when the actuator is installed at the rear end of the seat cushion the spring is installed in the upper housing. When the seat belt is stretched tight, such as in the event of a collision, the actuator is activated to maneuver the springs of the anti-submarine seat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and advantages of the present invention will be better understood by reference to the following detailed description, which should be read in conjunction with the accompanying drawings in which: 
     FIG. 1 is a side view of an embodiment of an anti-submarine seat for an automobile according to an embodiment of the present invention; 
     FIG. 2 is a top plan view of the anti-submarine seat of FIG. 1; 
     FIGS. 3 a  and  3   b  are enlarged perspective views of an embodiment of the anti-submarine mechanism of an embodiment of the present invention; and 
     FIG. 4 is a side view of an embodiment of the anti-submarine seat for the automobile showing an operational state of the anti-submarine seat according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, an embodiment of the anti-submarine seat for an automobile includes an upper seat frame  11  fixedly attached to a bottom portion of a seat cushion. Also shown is a lower seat frame  12  mounted to the floor of the automobile. Spring-type actuators  10  for supporting the seat cushions are interposed between the upper seat frame  11  and the lower seat frame  12 . 
     FIG. 2 shows the actuators  10  equally disposed over the total sectional area of the seat cushion. In a preferred embodiment, about four actuators  10  are disposed at a front end of the seat cushion and about eight actuators  10  are disposed at the rear end of the seat cushion. 
     Referring to FIGS. 3 a  and  3   b , the actuator  10  includes a cylindrical upper housing  13 . The cylindrical upper housing  13  is configured to be coupled with the lower surface of the upper frame  11  of the seat bottom. A cylindrical lower housing  14  slidably interacts with the cylindrical upper housing  13  and is configured to be coupled to the an upper surface of the lower seat frame  12 . In a preferred embodiment the lower housing  14  is inserted into the upper housing  13 , FIG. 3 a . In an alternative embodiment the upper housing  13  is inserted into the lower housing  14 , FIG. 3 b.    
     A spring  15  and a spring seat  16  are included in the actuator  10 . The spring  15  and the spring seat  16  can be installed in either the lower housing  14  or in the upper housing  13 . The spring  15  and the spring seat  16  are fixed in the lower housing  14  or in the upper housing  13  by means of a wedge-shaped spring fixing pin  17 . The wedge-shaped spring fixing pin  17  is configured to selectively control the actuator  10 . 
     As shown in FIG. 3 a , when the actuator  10  is installed at the front end of the seat cushion, the spring  15  and the spring seat  16  are installed in the lower housing  14 . The wedge-shaped spring fixing pin  17  is disposed at a position above the spring  15  and the spring seat  16 . In use, when the wedge-shaped spring fixing pin  17  is released by the actuator  10 , the elastic force of the spring  15  acts to push the spring seat  16  upwards. 
     In the alternative embodiment shown in FIG. 3 b , where the actuator  10  is installed at the rear end of the seat cushion, the spring  15  and the spring seat  16  are installed in the upper housing  13 . The wedge-shaped spring fixing pin  17  is disposed at a position below the spring  15  and the spring seat  16 . In use, when the wedge-shaped spring fixing pin  17  is released by the actuator  10 , the elastic force of the spring  15  acts to force the spring seat  16  downwards. 
     In a preferred embodiment the wedge-shaped spring fixing pin  17  is connected to a seat belt, FIG.  4 . The wedge-shaped spring fixing pin  17  disengages form the actuator  10  in accordance with movement of the seat belt. Thus, when the seat belt is stretched tight, as during a collision, the wedge-shaped spring fixing pin  17  disengages from the actuator  10 . 
     Hereinafter, the operation of an embodiment of the anti-submarine seat for the automobile according to an embodiment of the present invention will be described in detail with reference to the drawings. 
     FIG. 4 shows the anti-submarine seat of an embodiment of the present invention in use. In the case of a collision, when the occupant stretches the seatbelt tightly, the wedge-shaped spring fixing pin  17  disengages from the upper housing  13 . This prompts the spring  15  of the actuators  10  located at the front end of the seat (toward the knees of the passenger) to extend upwards and the springs of the actuators  10  located under the occupants seat bottom to descend downwards. Therefore, the front end of the seat cushion rises and the rear end of the seat cushion drops down. This helps restrict the occupants pelvis region from slipping forward during a collision. 
     While the present invention has been described with reference to a particular embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be effected without departing from the spirit and scope of the invention. The scope of the invention is not intended to be defined by the above description of particular embodiments but is intended to be defined by the appended claims.