Abstract:
A neck rest for a seat of an automobile has a neck rest body which includes a neck rest cushion and at least two neck rest rods connected with the neck rest body, the neck rest rods being accommodated in the back rest of the seat. Each of the neck rest rod has a support portion attached thereto. The neck rest body includes a housing which has a front wall and a rear wall, the cushion being attached to an outer side of the front wall and the rear wall, with the support portion being located in the housing between the front and the rear walls. The housing is moveable between a basic position and an extended position.

Description:
RELATED APPLICATIONS 
   The present application is based on, and claims priority from, German Application No. 10 2004 017 688.4, filed Apr. 10, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety. 
   FIELD OF THE INVENTION 
   The invention relates to a neck rest for seats of automobiles according to claim  1 . 
   BACKGROUND OF THE INVENTION 
   DE 199 61 617 A1; DE 199 51 966 A1 or DE 101 42 625 A1 have made known a neck rest which has a strut member which can be displaced towards the front on the seat user&#39;s head, and an impact member actuating the strut member. When there is an impact onto the rear end of the vehicle the impact member will be actuated and the strut member is displaced towards the front. The strut member is supported on the cushion holder via pivoting arms. In DE 199 51 966 A1, the strut member forms part of the neck rest cushion which consists of two components which are connected to each other via joints. The impact member can interact with the strut member via a pull rope and can be in communication with a release element. 
   DE 102 08 620 describes a neck rest for the seats of automobiles which has a fixed support portion and a second support portion for a movable cushion component which is movably supported in the first support portion. The second support portion is pivotally supported about a lower horizontal axis in the first support portion and an actuation device is defined by a spring which biases the second support portion. A controllable locking device maintains the second support portion in the retracted position on the first support portion. A third support portion is supported to be displaced on the second support portion between a lower and an upper position. The third support portion is biased by a second spring towards the upper position. A second controllable locking device maintains the third support portion in the lower position with the second locking device being released when the second support portion has reached a predetermined pivoting angle. This design is intended to help in achieving an optimum load absorption with no risk for the seated person to be injured during a rear-end collision. 
   Neck rests of this type are also referred to as crash-active neck rests. Their characteristic feature is that a seat user&#39;s head which will bounce back during a crash moves through a distance which is as short as possible until it hits against the neck rest. This distance possibly is relatively long when a passive neck rest is used and there is a risk for the head not to be supported at the proper point so that backbone lesions cannot be ruled out. 
   The disadvantage of the extendable neck rests which are known is that they comprise multiple elements. This involves relative large expenditure for their manufacture, specifically for its cushion. Moreover, their appearance possibly is not very pleasing because there is a circumferential gap between the adjacent components of the known crash-active neck rest. 
   SUMMARY OF THE INVENTION 
   It is the object of the invention to provide a neck rest for automobiles which, while having crash active properties, is of a simpler construction and allows for a cushion and a covering as for conventional standard neck rests. 
   The object is achieved by the features of claim  1 . 
   In the inventive neck rest, a support portion is fixedly attached to the two neck rest rods. The neck rest body has a shroud-like housing which has a front wall and a rear wall. A cushion can be mounted on the front side of the front wall. The housing may altogether be provided with a single-piece covering. The support portion is located within the housing between the front and rear walls. The shroud-like housing is movably supported between a rear basic position in which the support portion is near or adjacent to the inner side of the front wall and an extended position in which the support portion is remote from the front wall. A linkage is hinged between the support portion or the neck rest rods and the front wall, respectively, and a spring arrangement biases the linkage or housing, respectively, towards the extended position. A releasable locking device locks the housing or linkage, respectively, in the basic position and a releasing device, upon its actuation, releases the locking device whereby the housing is moved from the basic position to the extended position. Strut means support the linkage or the housing in its extended position on an abutment, which prevents the neck rest body, on striking the cushion, from being moved back towards the basic position. 
   Upon a release of the locking device, the neck rest body is rapidly advanced towards the seat user&#39;s head wherein the design of the linkage, according to an aspect of the invention, is such that the neck rest body is moved upwards at the same time, which causes the moving component to obliquely point upwards. The locking device is released via appropriate means detailed reference to which will not be made and which are known already from the previously described state of the art. 
   The fact that the neck rest body has a housing which is more or less closed circumferentially makes it commonly possible to provide it with a cushion and a cloth covering. When the body is released and is displaced to the extended position from the basic position the body will be moved as a whole rather than individual components thereof are moved as is the case in the state of the art. This allows to give the neck rest body a relatively simple construction and, as was mentioned before, a particularly simple covering as is used in conventional neck rests. 
   The shroud-like housing of the neck rest body preferably is open in the downward direction so that it can be slid over the neck rest rods and the support therebetween. Various designs of a linkage can be imagined and are possible. To this end, an aspect of the invention provides for a scissors type linkage having a pivoting lever and a strut lever which are pivotally linked to each other between the ends. The pivoting lever has its upper end pivotally linked to the support portion or neck rest rods and has its lower end hingedly linked to the housing. The strut lever has its upper end guided approximately vertically within the housing whereas it has its lower end supported on at least one supporting surface when the neck rest body is in the extended position. 
   A scissors type linkage of this type needs to be biased. Therefore, an aspect of the invention provides that the pivoting lever is biased by a leaf spring towards the extended position. It further is useful to provide a biasing spring also between the two levers. In this conjunction, an aspect of the invention provides that the strut lever is biased by a coil spring towards the extended position on its pivoting axis where at least one end of the coil spring is supported on the pivoting lever. This design allows to displace the neck rest body to the extended position particularly rapidly. 
   For a guidance of the strut lever, an aspect of the invention provides for its upper end to have a guide rod which cooperates with a vertical elongated hole in the interior of the housing. The elongated hole is preferably located on a portion in the housing that is mounted on the inner wall, preferably the side wall of the casing. According to a further aspect of the invention, this elongated hole may have saw teeth on a hole wall which faces the front wall of the casing. If the impact of the head takes place while the neck rest is moving to the extended position at a time where the neck rest has not reached yet its final extended position the guide rod is adapted to engage a gap between adjacent saw teeth, thus defining a support for the bearing rod. The support is enhanced if the support portion, according to a further aspect of the invention, has vertically superimposed stop steps which are adapted to support the lower end of the strut lever. The saw teeth and steps can be designed such that the lower end of the strut lever is supported on one of the steps when the upper end has its guide rod positioned in a gap between adjacent saw teeth. In this manner, the neck rest body is also active as an impact-absorbing member in intermediate positions. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will now be described in more detail with reference to an embodiment. 
       FIG. 1  shows a perspective view of a neck rest of the invention in the extended position as seen from the front side. 
       FIG. 2  shows a perspective view of a neck rest of  FIG. 1  as seen from the rear side. 
       FIG. 3  shows a perspective view of a neck rest of  FIG. 1  in the basic position as seen from the front side. 
       FIG. 4  shows a perspective view of a neck rest of  FIG. 3  as seen from the rear side. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIGS. 1 through 4 , two neck rest rods  10 ,  11  can be seen which are connected to each other via a transverse rod  12  at the upper end. The neck rest rods  10 ,  11  are received in appropriate receptacles in a back rest of an automobile seat which is not shown. The neck rest rods have mounted thereon a neck rest body  14  which will be described in detail below. 
   A plate-shaped support portion  16  is fixedly linked to the neck rest rods  10 ,  11  at the lateral ends and extends between these two ends below the transverse rod  12  interconnecting the rest rods  10 ,  11 . A pivoting lever  18  is pivotally supported on the transverse rod  12 , i.e. by means of two spaced bearing rings. The pivoting lever  18 , which is relatively broad, has a first recess  20  ( FIG. 1 ) and a second recess at the lower end. The recess  20  is traversed by a strut lever  22  which is pivotally supported in the middle of the recess as is outlined by the bearing pin  24  in  FIGS. 1 and 3 . The strut lever  22  has two parallel-spaced arms each at the upper end and lower end. The lower arms support a bearing rod  26  ( FIGS. 1 and 3 ). The upper parallel arms support a guide rod  28 . The guide rod  28  laterally extends horizontally outwards beyond the respective arms. 
   The pivoting lever  18  is biased by a leaf spring  30  which is mounted on the transverse rod  12 , namely in the direction away from the rods  10 ,  11 . The bearing pin  24  has disposed thereon a coil spring  32  which supports its ends  34  on the pivoting lever  18 . As a result, a bias has built up between the pivoting lever  18  and strut lever  22  and tends to move apart this lever in a scissors fashion as is illustrated in  FIG. 1 .  FIG. 1  shows the extended position of the levers  18 ,  22  while the basic position can be appreciated in  FIG. 3 . 
   At the lower end of the support portion, approximately in the middle, a two-armed bearing projection  36  is formed which pivotally supports a locking lever  38 . The locking lever  38  can be seen from the rear side in  FIGS. 2 and 4 . It is biased in front of a spring  39  in a released position. It interacts with an electromagnet  40  which actuates a locking pin  42 . The pin  42  is retracted in  FIGS. 2 and 4 , thus enabling the locking lever  38  to be freely pivoted. On the contrary, if the pin  42  is caused to travel leftwards to the locking position the locking lever  38  will be able to lock the pivoting lever  18  and strut lever  22  in the basic position shown in  FIG. 3 . For this purpose, the locking lever  38 , which is formed like a hook, grips over a portion of the rod  26  which extends crosswise through the lower end of the pivoting lever  18  and, by doing so, is also extended across and through the recess. In the basic position, the fork-like bearing device extends through another recess  44 , thereby allowing the locking lever  38  to grip behind the portion of the rod  26  facing it. 
   In  FIG. 1 , it can be appreciated that a plurality of superimposed support steps  48  are laterally formed next to the bearing projection  36  in the support portion  16 . The bearing rod  26  can support itself on one of the steps  48  in various positions of the lever  22 . One support is shown on the uppermost step in  FIG. 1 . It is understood that a step assembly which is identical to the assembly  48  is also provided on the opposite side of the bearing projection  36  for the other, lower arm of the strut lever  22 . 
     FIGS. 1 through 4  further allow to see that a shroud-like housing  50  is slid over the described assembly from the top on the neck rest rods  10 ,  11 . The housing has a front wall  52 , a rear wall  54 , a ceiling  56 , and side walls which are not designated. The housing  50  is larger in width in a horizontal direction, which makes it possible for the lever assembly and the support portion  16  to bear relatively closely on the front wall  52  in the basic position of  FIG. 3  whereas if the levers  18 ,  22  are in the extended position the rear wall  54  is relatively close to the support portion  16 . The housing, which is formed from an appropriate plastic material like the remaining components, for example, with the exception of the neck rest rods  10 ,  11  serves for accommodating a cushion (not shown) on the front wall  52  and a covering over the remaining components as is generally common and known for neck rests. As can be recognized from FIGS.  1  through  4  the walls of the shroud  50  are shown as being transparent to make the interior clearly visible. The insides of the two side walls of the housing  50  have formed thereon elongate holes one of which is can be seen at  58  in  FIGS. 1 and 3 . The elongate holes  58  extend approximately vertically and are fixed in a thickened or separated portion within the housing  50 . The elongate holes  58  have saw teeth  60  on the side facing the front wall  52 . As further is apparent from  FIGS. 1 and 3  the ends of the guide rod  28  engage the elongate holes  58  and interengage with the saw teeth  60 , if required. In the basic position, the guide rod is at the upper end of the elongate hole  58  ( FIG. 3 ) whereas the rod  28  strikes the lower end of the elongate hole  58  in the extended position 
   The way of operation of the neck rest assembly described will be explained below. Its function consists in being moved from the basic position illustrated in  FIGS. 3 and 4  to an extended position of  FIGS. 1 and 2  in a “crash case”. To initiate this motion, there is a member (not shown) in the automobile that provides a control command to the electromagnet  40  in the case of a tailgating collision. The pin  42  is extended in the basic position and locks the locking lever  38  in place (which is not shown in  FIG. 4 , however). When the pin  42  is retracted by the electromagnet  40  to the position shown in  FIG. 4  the locking lever  38  is released and the leaf spring  30  and the coil spring  32  move the levers  18 ,  22  apart. The pivoting lever  18  is swung away from the support portion  16  and the strut lever  22  is swung away clockwise relative to the pivoting lever  18 , to the positions shown in  FIG. 1 . At this stage, the guide rod  28  grips under the last saw tooth of the elongate hole  58  and the bearing rod  26  rests on the uppermost step of the step assembly  48 . Now, when a impact is exerted on the rear wall  54  the shroud  50  and, hence, the neck rest body  14  will remain in the position illustrated in  FIGS. 1 and 2  because the pivoting lever  18  and the strut lever  22  are prevented from moving to the basic position. The pivoting lever  18  supports itself on the strut lever  22  and this one does on one of the steps of the step assembly  48 . The guide rod  28  prevents the bearing rod  26  from sliding off the steps  48  by causing the latter rod to get locked by the lowermost saw tooth. 
   If the head strikes the front side of the neck rest body  14  at an earlier time than the extended position of  FIG. 1  is reached the neck rest body can be supported nevertheless in an intermediate position between the basic and extended positions since the bearing pins are supported on one of the lower steps  48  and the guide rod  28  engages a gap between the upper saw teeth  60 . 
   The shift described for the shroud-like housing  50  is not only performed horizontally, but also has a vertical component. This is the way the neck rest cushion (not shown) is moved towards the back of seat user&#39;s head if the user shoots backwards because the vehicle experiences a crash. 
   Finally, it should be added that the projecting ends of the rod  26  are received in appropriate bearing openings which are provided on the side walls in the interior of the shroud-like housing  50 , but are not shown here. In this manner, the pivoting lever  18  is hinged to the shroud-like housing  50 .