Abstract:
An actuator of an active headrest apparatus for a vehicle, which is operably connected to a headrest assembly and selectively allows a headrest of the headrest assembly to pop out forwards when a vehicle collision occurs, may include a housing installed on a seatback frame and formed with a guide groove, an operating plate elastically supported over the housing, an operating bracket arranged between the housing and the operating plate and having a guide projection slidably inserted into the guide groove of the housing, and an operating wire unit connecting the operating bracket with the headrest assembly, wherein the operating wire unit includes an operating wire and an operating wire retainer to slidably receive the operating wire therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Application No. 10-2008-0118376 filed on Nov. 26, 2008, the entire contents of which application is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an active headrest apparatus for a vehicle and an actuator thereof 
     2. Description of Related Art 
     A vehicle headrest is installed on the top of the back of a vehicle seat to support the head and neck of an occupant. The vehicle headrest prevents the head and neck of the occupant from being injured by the backlash of the body during a collision and ensures a comfortable ride by supporting the head and neck of an occupant under normal driving conditions. 
     As shown in  FIG. 6 , the active headrest apparatus of the prior art includes a seat frame  20 , a rotational shaft  40  rotatably installed inside the seat frame  20 , a shock suspension  50  connected to the rotational shaft  40  and rotatably installed around the rotational shaft  40  inside the seat frame  20 , a headrest  10  located on the top of the seat frame  20 , and connecting rods  30  extending through guide holes formed in the top portion of the seat frame  20  to link the shock suspension  50  with the headrest  10 . 
     In the conventional active headrest apparatus, the headrest is moved up and forward at the same time by a crash test dummy during a rear-end collision and then moves back to the initial position without maintaining the position moved to when the dummy moved forwards. On the other hand, the upper body of the occupant is instantaneously pushed forward by a seatback and the neck of the occupant performs a relative motion with respect to the upper body because of the inertial force. Like this, the relative motion of the neck may apply considerable pressure to the neck joint and the soft tissues around the neck. 
     The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     Various aspects of the present invention are directed to provide an active headrest apparatus for a vehicle and an actuator thereof, wherein an operational reaction in accordance with a vehicle collision happens immediately, a foreign body feeling because of the shock suspension can be removed, and a seated occupant&#39;s head and neck are effectively protected from being injured due to a car collision. 
     The actuator of an active headrest apparatus for a vehicle, which is operably connected to a headrest assembly and selectively allows a headrest of the headrest assembly to pop out forwards when a vehicle collision occurs, may include a housing installed on a seatback frame and formed with a guide groove, an operating plate elastically supported over the housing, an operating bracket arranged between the housing and the operating plate and having a guide projection slidably inserted into the guide groove of the housing, and an operating wire unit connecting the operating bracket with the headrest assembly, wherein the operating wire unit includes an operating wire and an operating wire retainer to sidably receive the operating wire therein. 
     The operating bracket may include a first operating bracket, to which one end portion of the operating wire is fixed, and a second operating bracket, to which one end portion of the operating wire retainer is fixed so as to move the first and second operating brackets in opposite directions each other while the first and second operating brackets are pressed or released by the operating plate, wherein the guide groove includes a pair of guide grooves formed in either end portion of the housing, to receive guide projections of the first and second operating brackets respectively, wherein each pair of the guide grooves formed in one end portion of the housing is formed to extend outwards with a downward inclination in an opposite direction with each pair of the guide grooves formed in the other end portion of the housing with respect to a movement direction of operating plate, and wherein the first and second operating brackets have incline planes respectively and contact with a lower portion of the operating plate, the lower portion of the operating plate having corresponding inclinations to the incline planes of the first and second operating brackets. 
     The incline planes of the first and second operating brackets may be formed in an opposite direction each other with respect to a movement direction of the operating plate. 
     In another aspect of the present invention, the operating plate has an operating projection extending downwards, and the housing has an insertion groove to receive the operating projection therein and to elastically support the operating projection via an elastic spring disposed in the insertion groove. 
     The headrest assembly may include a headrest drive module, and a latch module which is connected with the operating wire so as to lock/unlock the headrest to/from the seatback frame, the latch module unlocking the headrest when the operating wire is pulled up and the unlocked headrest popping up forwards by the headrest drive module when the vehicle collision occurs, wherein the headrest drive module includes a main bar fixed to the seatback frame, a sliding cap slidingly coupled to the main bar, and a sliding bar pivotally coupling the sliding cap and the headrest, wherein the sliding cap is elastically compressed in a normal stat and wherein the latch module may include a latch lever pivotally coupled to the seatback frame, one end of which is connected to the other end of the operating wire, a release lever pivotally coupled to the headrest, one end of which is selectively engaged with the latch lever and the other end of which is selectively engaged with a lock bar fixed to the headrest. 
     According to various aspects of the present invention, the actuator for allowing the headrest to pop out forward when a vehicle collision occurs is installed in the lower portion of the seatback frame. This is advantageous since the actuator having this construction can more rapidly perform the operating reaction than the actuator installed in the upper portion of the seatback frame can. 
     The present invention is also advantageous in terms of improved product control as well as reduced cost and weight due to having a reduced number of product parts. Here, a series of operations of popping out the headrest to the front can be realized by a simple construction of the actuator wherein the operating wire is pulled up when a car collision occurs. 
     In addition, since the operating force of the actuator in accordance with the present invention can be easily adjusted by controlling the tilted angle of the guide groove, the wire length, or the spring force, the actuator can be variously applied depending on the type of vehicle and the operating environment of the vehicle. 
     Furthermore, since the conventional shock suspension installed in the middle portion of the seatback is not required in the present invention, it is also advantageous in that a foreign body feeling due to the shock suspension can be removed and the surplus space of the middle portion of the seatback can be utilized. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a configuration view illustrating an exemplary active headrest apparatus for a vehicle in accordance with the present invention. 
         FIG. 2  is a perspective view illustrating an exemplary actuator of the active headrest apparatus for a vehicle in accordance with the present invention. 
         FIG. 3  is a cross-sectional view taken along line “A-A” of  FIG. 1 . 
         FIG. 4  is a configuration view taken along line “B-B” of  FIG. 1 , showing an exemplary latch module of the active headrest apparatus of the present invention. 
         FIG. 5A  is a lateral sectional view taken along line “C-C” of  FIG. 1 , showing an exemplary headrest drive module of the active headrest apparatus of the present invention prior to operation. 
         FIG. 5B  is a lateral sectional view taken along line “C-C” of  FIG. 1 , showing the headrest drive module of the present invention after operation. 
         FIG. 6  is a configuration view illustrating a conventional active headrest apparatus for a vehicle. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     As shown in  FIGS. 1 to 3 , an active headrest apparatus for a vehicle of various embodiments of the present invention is characterized by a simple configuration, in which an actuator  100  is installed in the lower portion of the seatback frame  200 , with an operating wire  155  of the actuator being pulled up by an operating bracket  140 , which slides in vehicle collision. With this configuration, product control is improved and immediate operating reaction can be realized. 
     The active headrest apparatus includes a headrest assembly, which allows a headrest to pop out forward when a car collision occurs, and the actuator  100 . Here, the headrest assembly includes a headrest drive module for driving the headrest  210  forward and a latch module  400  selectively locking or releasing the headrest drive module. 
     In more detail, the actuator  100  installed in the lower portion of the seatback frame  200  plays a role of releasing the locking of the headrest drive module when a car collision occurs. 
     To realize this function, the actuator  100  includes a housing  110 , an operating plate  120  elastically supported on the housing  110 , an operating bracket  140  arranged under the operating plate  120 , and the operating wire retainer  150  and the operating wire  155  connected with the operating bracket  140  to transfer push movement from the operating plate  120  to the latch module  400 . 
     The housing  110  is a supporting case enclosing the aforementioned parts and is fixedly installed in the lower portion of the seatback frame  200 . Like this, since the buttocks react faster than the shoulders of an occupant can react to a car collision, the actuator  100  located in the lower portion of the seatback frame  200  can react faster than that located in the top portion of the seatback frame  200 . Accordingly, the actuator  100  can immediately react to the car collision. 
     The housing  110  elastically supports the operating plate  120  via a plurality of elastic springs  112 . Here, a plurality of the elastic springs  112  can be evenly arranged under the operating plate  120  to support the operating plate  120  and balance it. In various embodiments of the present invention, the elastic springs  112  are composed of four elastic springs  112  supporting either corner of the operating plate  120 . 
     Insertion grooves  111  formed in the housing  110  elastically support operating projections  121  of the operating plate  120  via the elastic springs  112 . Each of the insertion grooves  111  guides the movement of a corresponding one of the operating projections  121  when the operating plate  120  is pressed by a backward sliding of the occupant. 
     Guide grooves  130  guiding the sliding movement of the operating bracket  140  are respectively formed in both ends of the housing  110 . The guide grooves  130  function to guide the movement of the operating bracket  140 , which will be described later, and extend outwards with a downward inclination from the top central portion the housing  110 . 
     The operating plate  120  is installed on the top of the housing  110 , with the elastic springs  112  interposed therebetween, and is structured to be pressed by the upper buttocks of the occupant when a car collision occurs. A plurality of the operating projections  121  extending downwards from the operating plate  120  are fitted into the insertion grooves  111  of the housing  110 . Each of the elastic springs  112  is interposed between each of the operating projections  121  and a corresponding one of the insertion grooves  111 . 
     Under the operating plate  120 , the operating bracket  140  is installed to convert the downward motion into the lateral movement. The operating bracket  140  is in contact with the lower portion of the operating plate  120  via incline planes  143 , and is guided to the guide grooves  130  of the housing  110  via the projections  144 . When the operating plate  120  moves downwards, the downward motion of the operating plate  120  can be converted into the lateral movement by the operating bracket  140  moving along the slope of the guide grooves  130  of the housing  110 . 
     The operating bracket  140  includes a first operating bracket  141  and a second operating bracket  142  arranged on both ends thereof The first operating bracket  141  is fixed with one end of the operating wire  155 , and the second operating bracket  142  is connected to the operating wire retainer  150  and guides the passing-through of the operating wire  155 . When the first operating bracket  141  and the second operating bracket  142  become wider towards both ends of the operating plate  120  by the downward movement of the operating plate  120 , the operating wire  155  can be pulled up by the first operating bracket  141 . 
     The operating wire  155  connects the operating bracket with the headrest drive module through the operating wire retainer  150 . In particular, the headrest  210  can pop out forward via the headrest drive module when the operating wire  155  is pulled up. 
     The headrest drive module provides the operating force to move the headrest  210  forward. While the headrest drive module is normally held in the locked status via the latch module  400 , the latch module  400  is unlocked by the operation of the operating wire  155  and the operating wire retainer  150  when a car collision occurs. As a result, the headrest drive module drives the headrest  210  to pop up forward, thereby protecting the occupant&#39;s neck when the car collision happens. 
     As shown in  FIG. 4 , the latch module  400  includes a release lever  420  fixing a lock bar  211  of the headrest drive module and a latch lever  410  linking to the operating wire  155  while binding the release lever  420 . 
     When the latch lever  410  is pulled by the operating wire  155 , it rotates counterclockwise from the view of  FIG. 4  while turning the release lever  420  clockwise from the view of  FIG. 4  so that the lock bar  211  rotates in the bound position. 
     The latch lever  410  is provided with a returning spring. When the pushing pressure of the operating plate  120  is removed, the returning spring can push out the operating wire  140  while returning to the original position. At this time, the operating wire  155  can return to the original position and the operating bracket  140  connected to the operating wire retainer  150  and the operating wire  155  can return to the original position as well by the return spring. 
     As shown in  FIG. 5A , the headrest drive module includes the lock bar  211  fixedly installed on the headrest  210  and normally bound by the release lever  420  of the latch module  400  wherein the release lever  420  is rotatably fixed to the seatback, a main bar  330  fixedly installed on the seatback, a sliding cap  341  movably installed in the longitudinal direction along the main bar  330 , a compressed spring  320  installed inside the sliding cap  341  so as to maintain the compressed status in normal times, and a sliding bar  340  having one end connected to the sliding cap  341  and extending forward with an inclination and the other end fixed on the headrest  210 . 
     When the lock bar  211  for the release lever  420  is unlocked, as shown in  FIG. 5B , the sliding cap  341  as well as the sliding bar  340  moves up along the main bar  330  while the condensed compressed spring  320  is stretching. At this time, the headrest  210  can pop out forward while the end of the sliding bar  340  is also moving up. Consequently, the neck of the seated occupant can be protected via the headrest  210  that is popped out forward. 
     Although various embodiments has been described with reference to the construction in which the headrest  210  is popped out forward by the unlocking of the headrest drive module via the pulling motion of the operating wire  155 , this is not intended to limit an exemplary embodiment of the present invention. Rather, various embodiments of the present invention may embrace all the constructions, in which the headrest  210  is popped out when the operating wire  155  of the actuator  100  is pulled up during a vehicle collision. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, and “forwards” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.