Abstract:
A headrest mounting for a seat, e.g,. for a motor vehicle, includes a mounting member ( 15 ) fitted in the seat backrest and affording an upwardly-open passage ( 21 ) for sliding reception of a downwardly extending headrest post ( 13 ); a locking member ( 25 ) extending transversely of the passage and having an opening ( 27 ) through which the post extends; spring means ( 31 ) biasing said locking member to become more inclined from the perpendicular to the longitudinal axis of the post, so boundaries of said opening frictionally grip the post, and release means ( 23, 41 ) for causing the locking member to be oriented more nearly perpendicular to the longitudinal axis of the post to release the post for longitudinal movement within said passage.

Description:
BACKGROUND OF THE INVENTION  
       Field of the Invention  
         [0001]    This invention relates to the mounting of headrests for seats. The invention has been devised primarly for motor vehicle scats, but it will be appreciated it will be applicable to seats generally, e.g. for other forms of transport, where similar or analogous requirements arise.  
           [0002]    A headrest is provided on a motor vehicle seat for constraining the head of an occupant of the seat against rearwards movement. This may be to enhance the comfort of the seat&#39;s occupant by enabling him or her to rest the head back against the headrest, but also has the purpose of preventing unconstrained rearward movement of the head if the vehicle is involved in a crash. Thereby “whiplash” injury to the neck of the seat&#39;s occupant may be reduced.  
           [0003]    In order that the headrest can fulfil this function, it is usual to provide some form of adjustability of the headrest, at least in the upwards and downwards direction relative to the seat to enable it to be appropriately positioned when the seat is occupied by persons of different height. Forwards and rearwards adjustment, and/or angular adjustment, of the headrest may also be provided for. The present invention relates to the provision of the upwards and downwards adjustment of a headrest relative to a seat.  
           [0004]    The most common configuration of headrest for a vehicle seat is that the part thereof which is contactable by the seat&#39;s occupant&#39;s head, which is upholstered to match the seat&#39;s upholstery and will herein be termed the pillow, is carried by a frame including spaced, substantially parallel, downwardly extending posts which are engageable in upwardly open sockets provided in the seat back. The extent to which the posts are received in the sockets determines the height of the headrest relative to the seat back. Locking means associated with the sockets (usually only one of them) enables the headrest to be fixed at the desired height.  
           [0005]    In many headrests, the locking means comprises detent means engageable with a number of formations such as notches spaced lengthwise of the headrest post so that the headrest height is fixed according to which one of the formations is engaged. This, of course, means that the headrest height can only be adjusted stepwise. Further, such notches can represent a trapping hazard to the fingers, particularly of children. It would be desirable if formations such as notches could be dispensed with, and if the headrest height could be adjusted steplessly within the limits determined by the length of the headrest posts and the dimensions of the sockets engaged thereby. There had been proposals for arrangements providing such stepless adjustment, but they have been complex arrangements and therefore expensive to manufacture.  
         SUMMARY OF THE INVENTION  
         [0006]    It is broadly the object of the present invention to provide for stepless adjustment of headrest height as above referred to, but in a simple and economical manner. Other objects and advantages of the invention will be pointed out in greater detail hereafter.  
           [0007]    According to the present invention, we provide a mounting member adapted to be fitted in a seat backrest and affording an upwardly-open passage for sliding reception of a downwardly extending headrest post; further comprising a locking member extending transversely of the passage and having an opening through which the post extends; spring means biasing said locking member to become more inclined from the perpendicular to the longitudinal axis of the post, so boundaries of said opening frictionally grip the post, and release means for causing the locking member to be oriented more nearly perpendicular to the longitudinal axis of the post to release the post for longitudinal movement within said passage.  
           [0008]    In order to be effective in frictionally gripping the post as above referred to, the opening in the locking member has to be dimensioned so that when the locking member lies perpendicular or close to perpendicular to the longitudinal axis of the post, opposed boundaries of the opening are clear of the post, but when the locking member is inclined from the perpendicular to the longitudinal axis of the post the boundaries of the post contact the latter.  
           [0009]    Such frictional gripping of a post by an inclined locking member is effective against movement of the post therethrough in one direction namely the direction which tends to cause the locking member to become more inclined from the perpendicular to the axis of the post. This increases the grip of the locking member on the post. Attempted movement of the post in the other direction, however, tends to return the locking member more nearly to the perpendicular to the axis of the post and thus decreases the grip of the locking member on the post, so the post is able to move in that direction through the locking member. In a mounting member for a vehicle seat headrest, the locking member should be effective against downwards movement of the headrest relative to the seat back so that if the headrest is to be moved in such direction the release means has to be operated, whilst upwards movement of the headrest relative to the seat back can be effected without requiring operation of the release means.  
           [0010]    Preferably the locking member is an element of sheet metal and it may be of resilient material having the spring means integral therewith.  
           [0011]    The locking member may be disposed in a lower part of the mounting member. This has the advantage that, if the post is marked by engagement of the locking member therewith, the marked part of the post will remain within the mounting member and thus invisible over at least the major part and preferably all the range of height adjustment of the headrest. The release means has to be operable from an accessible position on the mounting member, i.e. at a top portion thereof and accordingly preferably comprises a manually operable release member provided in an upper part, e.g. in a flange or escutcheon part at the top of the mounting member, connected to the locking member by transmission means.  
           [0012]    The transmission means conveniently comprises a pull rod member which may be of plastics material, integral with the release member.  
           [0013]    The release member may be or include a part which is movable, for causing release of the locking member, either generally in the direction of the length of the headrest post or, preferably, in the direction transversely to the length of the headrest post.  
           [0014]    The latter is easier to operate if the headrest is in its lowermost position close to the top of the seat backrest, with little room for a finger or fingers of a user to be inserted to operate the release member.  
           [0015]    As above described, a headrest usually comprises two spaced parallel posts which are engaged in respective mounting members spaced laterally of the seat. In general it will be sufficient for satisfactory looking of the headrest in an adjusted position if one of the mounting members is in accordance with the invention as above set forth.  
           [0016]    In this case, the other mounting member for the headrest may comprise releasable means for holding the respective headrest post captive to the mounting member. For complete removal of the headrest, action has to be taken to release the means which holds the headrest post captive to the second mounting member. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0017]    The invention will now be described by way of example with reference to the accompanying drawings, of which:  
         [0018]    [0018]FIG. 1 is a perspective view of a headrest mounting in accordance with the invention;  
         [0019]    [0019]FIG. 2 is an enlarged and more detailed perspective view of one headrest mounting member as shown in FIG. 3;  
         [0020]    [0020]FIG. 3 is a section through the mounting member of FIG. 2, in one operative condition;  
         [0021]    [0021]FIG. 4 is a section as FIG. 3, but in an alternative operative condition;  
         [0022]    [0022]FIG. 5 is an exploded perspective view of an alternative embodiment of headrest mounting member in accordance with the invention. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENT  
       [0023]    Referring firstly to FIG. 1 of the drawings, a backrest part of a vehicle seat is indicated generally at  10  and a headrest generally at  11 . The headrest comprises an upholstered pillow part  12  carried by a somewhat U-shaped frame of metal, e.g. steel, bar. The frame includes two spaced parallel posts  13 ,  14  which extend downwardly from the pillow part  12 . The posts  13 ,  14  are received in respective mounting members  15 ,  16  which are fitted in the seat backrest at the top thereof and define upwardly-open passages in which the posts  13 ,  14  are received for sliding movement lengthwise of the posts so that the headrest is adjustable in respect of its height above the seat backrest. Although not related to the present invention the pillow  12  may be adjustable forwardly and rearwardly, and/or angularly, relative to the frame  11 .  
         [0024]    Referring now to the remaining drawings, the mounting member  15  is shown in more detail in FIGS. 2, 3 and  4  and in the last mentioned drawing the post  13  is shown in situ. The mounting member comprises a moulded plastics body  20  in which is defined passage  21  for receiving the post  13  and at the top of the body  20  there is a flange or escutcheon formation  22  which accommodates release member  23  to be described in more detail hereafter. The escutcheon  22  lies on top of the upwardly presented top surface of the seat backrest  10  when the mounting member is fitted thereto.  
         [0025]    Towards the bottom of the body  20  there is a recess  24  in which is accommodated a locking member  25 . The locking member  25 , whose configuration is the same as the locking member in the embodiment of FIG. 5 and will be described in relation to that FIG., is of resilient metal such as spring steel and comprises a body part  26  in which there is an opening  27  surrounded by a rolled lip  28 . The opening  27  is circular, slightly elongated in one direction, or other shape and dimensioned so that the post  13  can move freely through it when the body part  26  is perpendicular or nearly so to the longitudinal axis of the post, but the post is frictionally engaged by boundaries of the opening when the body part is more inclined to such perpendicular orientation. The body  26  is provided with spaced lugs  29  in one end face and with lugs  30  in the opposite end face. Adjacent the lugs  30 , spring elements  31  are bent back to extend upwardly at an inclination to the body part  26  of the spring member. When received in recess  24 , as most clearly seen in FIG. 3, lugs  30  engage a rear wall of the recess  24  while spring elements  31  engage a top part of the recess to bias the body part  26  of the locking member so that it is inclined downwardly within the recess.  
         [0026]    The release member  23 , which is of moulded plastics material, is pivotably supported in the top part of the body  20  of the mounting member and has an integrally formed pull rod  33  guided in a formation  34  in the body  20  and having at its lower end a head  35 . The pull rod extends between the lugs  29  of the locking member and the head  35  beneath the adjacent end of the locking member. The result is that pivoting of the release member by depressing its accessible end part, as shown in FIG. 4, displaces the pull rod  33  upwardly and causes the body  26  of the locking member to be moved from the position in which it is shown in FIG. 3 in which it is substantially inclined to the longitudinal axis of post  13  to a position in which it is close to perpendicular thereto.  
         [0027]    When the locking element has its body portion  26  inclined downwardly as shown in FIG. 3, opposite edges of the opening  27  therein fictionally grip the post  13  and prevent the post from moving downwardly within the mounting member. Attempted such downward movement of the post causes the post to be gripped even more tightly, but upward movement of the post is possible as it causes the body portion of the locking member to be moved slightly to an orientation more nearly perpendicular to the axis of the post so the latter is gripped less hard. When it is required to move the post downwardly within the mounting member, pivoting movement of the release member  23  causes the part of the body member  26  having the lugs  29  to be lifted by the head  35  at the lower end of the pull rod  33 , to assume the orientation shown in FIG. 4 in which its frictional grip on the post  13  is released.  
         [0028]    Referring now to FIG. 5 of the drawings, this shows a mounting member which differs from that above described in respect only of the arrangement of its release member and its connection to pull rod  33 . The pull rod  33  and its head  35 , and the lower part of body  20  with its recess  24  for receiving locking member  25 , are all as above described and will not be described again. The same reference numerals are used in relation to such parts. The FIG. 5 embodiment differs in having a top flange or escutcheon part  40  which receives a release member  41  for sliding movement perpendicularly to the axis of post  13 . The release member  41  has an end abutment face  42  for engagement by a finger or thumb of a user, to press the release member in the direction of arrow  43  towards post  13 . The top of pull rod  33  is forked to form two spaced parallel curved limbs of which one is indicated at  44 , which join two lugs  45  on the release element  41  which lie to either side of the post  13  when received in the passage ( 46 ) in the mounting member. The limbs as  44  pass over respective correspondingly curved guide surfaces (not shown) in the upper part of the body  20  of the mounting member.  
         [0029]    Movement of the release member  41  in the direction of arrow  43  is transmitted by limbs  44  passing over their respective curved guide surfaces, to lift the pull rod  33  and disengage the locking member from the headrest post in the manner above described. The plastics material from which the release member  41 , lugs  45 , limbs  44  and pull rod  33  are integrally moulded is sufficiently flexible for the limbs to transmit to the pull rod the motion of the release member  41  in a direction perpendicular to that in which the pull rod is moved.  
         [0030]    To prevent inadvertent complete removal of the headrest  11  from the seat backrest  10 , the mounting member  16  which receives the post  14  of the headrest may include a stop means which cooperates with a formation such as a radial protuberance at or adjacent the lowermost free end of post  14 . The stop means may comprise a sleeve part of or associated with the mounting member  16 , which is movable angularly about the axis of the post to a position in which such protuberance can pass through the sleeve, but which normally is in a position in which the protuberance cannot pass. Alternatively any other form of stop cooperating with the post, but movable to a releasing position to permit withdrawal of the post from the mounting member, may be utilised.  
         [0031]    The invention thus provides for stepless adjustment of a headrest in a particularly neat and economical manner.  
         [0032]    In the above described embodiments of headrest mounting the locking member is disposed towards the bottom of the mounting member and it is then necessary to provide transmission means between the release member and locking member. It would in alternative arrangements be possible to provide a locking member in the top part of the mounting member in which case it may be operated on directly by a release member. For example a release member movable agularly as the release member in the embodiments of FIGS.  2  to  4  may cause a corresponding movement directly in the locking member, or a transversely displaceable release member as in the embodiment of FIG. 5 may have a cam formation or formations which engage the locking member.  
         [0033]    In the present specification “comprises” means “includes or consists of” and “comprising” means “including or consisting of” 
         [0034]    The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.