Abstract:
An automobile-seat headrest has a fixed support enclosed by a fixed pad and two rods which are connected to the support and which are received in the headrest bushes in a seat backrest, a second support for a displaceable pad being displaceably resting in the fixed support and allowing to set the displaceable pad between a retracted position at least partly received in the fixed pad and an advanced position, and vice-versa, wherein the displaceable pad is advanced relative to the fixed pad toward the head of the seated person, a drive device being provided to set the displaceable head pad into the advanced position.

Description:
TECHNICAL FIELD 
     The present invention relates to an automobile-seat headrest. 
     BACKGROUND ART 
     Conventional headrests consist of a padded part slidably mounted on two rods in the seat&#39;s backrest, said rods being inserted in the backrest&#39;s headrest bushes. The padded part contains a support connected to the head rest&#39;s rods. 
     In general the headrests are configured improperly or inadequately in a vehicle and assume a position matching the driver or passenger. In case of a rear-end collision, a large spacing between the head and the headrest entails pronounced tensile stresses in the neck that may result in substantial injuries to it. A case of improper position in particular results when the headrest is too low on the backrest. 
     The objective of the present invention is to create a headrest remedying the above defects. 
     SUMMARY OF THE INVENTION 
     As regards the headrest of the invention, a second support for a displaceable pad is displaceably mounted on the fixed pad, the displaceable pad being adjustable between a retracted position in the said fixed pad and an extended position, and vice versa, the displaceable pad when advanced being moved forward from the fixed pad toward the head of the seated person. The invention furthermore provides a drive device to set the displaceable pad into its extended position. 
     In one embodiment of the present invention, the displaceable pad when in its advanced position also is raised above the fixed pad. In this manner the displaceable pad not only is displaced relative to the head as regards the sitting position, but also it is raised with respect to the head. 
     In case of a rear impact on the vehicle, the displaceable pad, having moved toward the back of the driver&#39;s head, assures direct support for the driver&#39;s head and as a result the driver is virtually made safe against the so-called whiplash effect. Following the accident, the headrest may be moved back into its initial, that is the retracted position and shall be operational once more. 
     A number of designs are applicable to displaceably support the movable headrest at the fixed pad. Preferably a lever linkage shall be used, in particular a spring-loaded parallelogram. Once the spring has been released, for instance from a locked position, the parallelogram linkage is able to advance the displaceable pad and to move it near the back of the head of the seated person. It is understood that in case of impact on said displaceable pad, it may not yield excessively but instead shall absorb said impact. Accordingly in one embodiment of the invention, a stop is used that shall act as a rest for one or more levers of the parallelogram when on account of impact on the displaceable pad a force shall be exerted on it in the direction of the fixed pad. However locking mechanisms also are applicable that shall lock the displaceable and extended pad to absorb a pertinent force. Such locking action then must be eliminated once the displaceable pad must be returned into its rest position. 
     As mentioned above, the displaceable pad may be spring-loaded into the extended position, or a locking element may be used to lock the spring or the linkage against the spring bias in the retracted position. An appropriate drive device furthermore includes an unlocking element in order to release the lock. This goal may be attained in the present invention by using a cable. This cable must be positioned at a site appropriate for its activation when rear-end impact takes place. Illustratively this feature may be implemented by the pressure exerted by the seated person&#39;s back against the backrest when the vehicle&#39;s rear is impacted. 
     However the force setting the displaceable pad also may be applied to a component remote from the headrest and by cable force transmission. Again a number of designs are conceivable. One design of the invention employs a drive device with a first and a second element that are mutually displaceable in to-and-fro manner and which are kept apart by a spring that biases the two elements apart. One of said elements guides a carriage linked to a lever of which the other end is linked to the other element. A cable is affixed to the carriage. The carriage shall be displaced when the two elements are mutually moved to-and-fro. The carriage is adjusted in this manner and an adjusting force can be exerted on the cable which in turn sets the displaceable pad into the extended position. The support may be connected to the displaceable pad in the manner already described above. 
     Preferably the displaceable pad is received in part or in whole in the fixed pad. Accordingly, in one embodiment of the present invention, the fixed support shall exhibit a U-shape and the displaceable support shall be preferably planar, their dimensions being selected in a manner that the displaceable pad when in its rest position shall be received in a matching clearance in the fixed pad. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Illustrative embodiments of the present invention are elucidated below in relation to the attached drawings. 
     FIG. 1 is a front view of the supports of a headrest of the invention, 
     FIG. 2 is a view similar to that of FIG. 1 when the displaceable support of the headrest of the invention has been advanced, 
     FIG. 3 shows a detail of the headrest of FIGS. 1 and 2, 
     FIG. 4 shows the supports of an embodiment variation of the headrest of the invention, 
     FIG. 5 is a perspective of the rear of the supports of FIG. 4, 
     FIG. 6 is a partly cutaway perspective of a drive device for the headrest of FIGS. 4 and 5, 
     FIG. 7 is a perspective of the rear of a portion of the drive device of FIG. 6, 
     FIG. 8 is a perspective elevation of the drive device of FIG. 6, in the deactivated state, and 
     FIG. 9 is a view similar to that of FIG. 8, however in the activated state. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2 show a fixed headrest support consisting of two mutually spaced columnar segments  12 ,  14  and a plate  16  connecting them. The components  12  through  16  are integrally made of a suitable and strong plastic. Headrest rods  18 ,  20  are firmly affixed in the columnar segments  12 ,  14  and will be inserted into headrest bushes of an omitted backrest of an automobile seat. Padding omitted from this Figure but conventional and known as regards such headrest is mounted at the back of the described support  10 , at the top side and laterally from the columnar segments  12  and  14 . 
     A displaceable planar support  22  for a displaceable headrest component is situated between the columnar segments  12 ,  14 . Said support  22  also is made of a suitable, strong plastic. It may be moved to-and-fro between a retracted position shown in FIG. 1 wherein it is situated between the columnar segments  12 ,  14  and an advanced position shown in FIG. 2 wherein it projects from the fixed support  10  and furthermore is raised. For that purpose the displaceable support  22  is connected to a parallelogram bar linkage. The parallelogram bar linkage comprises a first an upper, relatively wide, lever  24  connected by a shaft  26  to the front side of the plate  16 . The shaft  26  is held in brackets, of which one ( 28 ) is shown, against the front side of the plate  16 . Brackets also are mounted on the back side of the planar support  22  which is shown only partly—actually it occupies the space between the columnar segments  12 ,  14 —and said brackets bear a shaft  30  in order to link the lever  24  to the back side of the displaceable planar support  22 . 
     Another shaft  32  is rotatably supported in corresponding but omitted brackets at the back side of the planar support  22  and is linked to two mutually parallel levers  34 ,  36 . The levers  34 ,  36  are linked in corresponding brackets at the front side of the plate  16 , however these particulars will not be discussed in detail. Springs  38 ,  40  are mounted on the shaft  26  on opposite sides of the lever  24  and bias the above described parallelogram linkage into a position shown in FIG.  2 . 
     The displaceable support  22  in turn is enclosed by omitted padding. Said support shall provide an advantageous rest for the rear of the head of the person sitting in the omitted seat when, due to a collision, the head shall be forced rearward. The levers  24 ,  34  and  36  slope upward and a spring or an omitted stop assures that the position shown in FIG. 2 shall not be vacated by pressure applied to the displaceable support  22  and further upward pivoting. 
     If the displaceable support  22  must assume the position shown in FIG. 1, it must be pivoted downward, optionally manually. In this process the rod  32  pivots behind a hook  42  shown in further detail in FIG. 3. A bracket  44  is integrated into the front side of the plate  16  and supports the hook  42  in pivotable manner, namely at  46  about an approximately horizontal axis. Moreover said hook is loaded downward by a spring  48 . By pivoting the rod  32  toward the rounded, oblique front side of the hook  42 , this hook shall be temporarily deflected upward and shall then snap over the rod  32  whereby the support  22  is kept in the position shown in FIG.  1 . Using a cable denoted by the reference  50 , the hook  42  may be pivoted upward. In this manner the springs  38 ,  40  allow pivoting the linkage and moving the support  22  into the position shown in FIG.  2 . 
     The operation of the cable  50  is omitted. It operates in the manner of a converter converting a collision at the vehicle rear (omitted) into a traction on the cable  50 . 
     Where elements identical or similar to those of FIGS. 1 through 3 also are used in FIGS. 4 and 5, the same reference numerals will be carried over. 
     FIG. 5 shows especially clearly the linkages of the levers  34 ,  24  and  36  to the back side of the displaceable support  22  which furthermore is also shown in full in this FIG. 5, rather than as in FIG. 4 where only half of it is displayed. 
     A guide  52  is situated in the in the longitudinal center of the pate  16  assuming the geometry of a half-bush which passes a cable  54  (also see FIG.  4 ). The cable is hooked by means of a toggle at  56  to a lever arm  58  projecting rearward beyond the pivot axis. Therefore, by pulling on the cable  54 , the planar support  22  may be pivoted from a position between the columnar segments  12 ,  14  into a position in front of them as shown in FIGS. 4 and 5. In this instance therefore the actuation of the displaceable support  22  is not initiated by a spring directly at the headrest, but remotely from the headrest by means of a drive device illustratively described in FIGS. 6 through 9. 
     The drive device of FIGS. 6 through 9 is denoted by the reference  60 . It comprises a first boxy part  62  telescopically nesting a second boxy part  64 . Four cross-sectionally circular guide pins  66  are configured at the ceiling wall of the boxy part  62  at its inward corners and said pins are received in circular guides  68  and furthermore are enclosed by helical springs  70 . 
     A carriage  74  is mounted in a clearance  72  of the ceiling wall of the boxy part  64 . The carriage  74  slides within the narrower portion of the clearance  72  and is fitted with (unreferenced) channels cooperating with the edges of the clearance  72 . As a result the carriage may be moved to-and-from between a position shown in FIG. 6 and a position shown in FIG.  7 . The cable  54  is affixed to said carriage. Furthermore a connecting lever  76  is linked to the carriage  74  which, as shown especially clearly in FIG. 8, is linked by its other end to the inside of the ceiling segment of the boxy part  62 . When the springs  70  of FIG.  8  and also of FIG. 6 are unstressed, the connecting lever  76  is supported somewhat obliquely and the carriage  74  shall be in its first position. If next the boxy parts  62 ,  64  are compressed, they shall approach each other while compressing the spring  70 . In this process the connecting lever  76  will pivot and it shall set the position of the carriage  74  into the other end position shown in FIG.  7 . In this manner a traction is exerted on the cable  54  and the displaceable support  22  shall be advanced into the position shown in FIGS. 4 and 5. If the compression between the parts  62 ,  64  decreases, the cable  54  shall be relaxed and the displaceable support  22  shall be able to pivot back into its initial position. 
     Illustratively the drive device  60  of FIGS. 6 through 9 may be activated, by being integrated into the backrest and by repeated pressures being applied from the back of the seated person. In this manner, in the event of a collision at the rear of the vehicle, advance of the displaceable support  22  shall be automatic.