Patent Publication Number: US-2023142193-A1

Title: Headrest for a vehicle seat

Description:
TECHNICAL FIELD 
     The invention concerns a headrest for a vehicle seat, in particular for the driver&#39;s seat of a truck. 
     The invention can be applied in heavy-duty vehicles, such as trucks, buses and construction equipment. Although the invention will be described with respect to a truck, the invention is not restricted to this particular vehicle, but may also be used in other vehicles such as railway vehicles (trains, tramways, etc.), military vehicles, as well as aircraft and helicopters. In summary, the invention could apply to any seat intended to accommodate a driver (or pilot) for long hours. 
     BACKGROUND 
     It is known that headrests are adjustable in height with respect to the backrest. This allows the driver to adapt this part of the seat to his morphology, and in particular to his size. 
     This also helps to avoid, or at least minimize, the damage caused by whiplash in the event of an accident. 
     To do this, it is essential that the headrest is properly adjusted. 
     In particular, the headrest must be adjusted so that it is neither too low nor too far from the driver&#39;s neck. Also, the upper edge of the cushion should preferably reach the top of the skull. 
     To provide even more comfort, some headrests can also be adjusted in the forward/reverse direction (in addition to the up/down direction). The driver can then move the headrest more or less forward, so as to avoid any empty space between his head and the headrest. 
     U.S. Pat. Nos. 8,038,219 B2 and 7,871,129 B2 disclose examples of head restraints that can be adjusted from front to back (or back to front) with respect to the backrest. 
     U.S. Pat. Nos. 5,642,918 and 10,099,582 B2 disclose examples of headrests that can be more or less inclined, so they can be adjusted in rotation. However, the mechanisms used to ensure this type of adjustment are relatively complex (and expensive), which is why they are relatively rare on vehicles. 
     It is these disadvantages that the invention particularly intends to remedy, by proposing a headrest equipped with a new adjustment system, which is simpler to use and easier to implement. 
     SUMMARY 
     The features of the head restraint according to the invention are defined in claim  1 . 
     Thanks to the invention, the headrest can be easily adjusted by acting on the control rod, for example by pressing a button. As soon as the button is released, the headrest automatically locks into the desired position. The adjustment mechanism is therefore very simple, easy to assemble and very robust over time. 
     Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention and other advantages of the invention will appear more clearly in the light of the description that follows of a method of making a headrest, given only as an example and made with reference to the attached drawings in which: 
         FIG.  1    is a perspective view of a truck conforming to the invention, including a seat with a headrest depending on the invention; 
         FIGS.  2  and  3    are side views of the headrest that is the subject of the invention, in two distinct configurations; 
         FIGS.  4 ,  5  and  6    are respectively top, side and front views of the mechanism inside the headrest allowing it to rotate over a certain adjustment range; 
         FIGS.  7  and  8    are two perspective views of the mechanism from different sides; 
         FIGS.  9  and  10    are two side views of the adjustment mechanism in position inside the headrest, showing two headrest adjustment positions; 
         FIGS.  11  and  12    are detailed views of the adjustment mechanism; 
         FIGS.  13  and  14    are cross-sectional views showing in detail the rotational adjustment possibilities of the head restraint; 
         FIGS.  15  and  16    are longitudinal sections along lines XV and XVI of  FIGS.  13  and  14    respectively. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION 
       FIG.  1    shows a vehicle, in particular a truck  2 , provided with a cabin  4  inside which is arranged a seat  6  on which the truck driver can sit. Even if  FIG.  1    shows a truck, it is obvious that the invention can be applied to any type of road vehicle, such as passenger cars, buses, construction machinery, etc. Also, one could consider applying the invention to railway vehicles (trains, trams, etc.), military vehicles, as well as aircraft and helicopters. In summary, the invention could apply to any seat intended to accommodate a driver (or pilot) for long hours. 
     Seat  6  is partly represented in  FIGS.  2  and  3    only, with a driver D present. Seat  6  includes a backrest  8  at the upper end of which is arranged a headrest  10  (or “head restraint”) allowing the driver to rest his head during journeys, especially during long journeys. In this document, the terms “upper” and “lower” (and assimilated) are to be interpreted in relation to a vehicle operating configuration, i.e. in a rolling vehicle configuration. 
     Headrest  10  includes a cushion  11  which is shown in  FIGS.  2  and  3    only and which encloses a mechanism for adjusting the orientation of the headrest  10  about a horizontal axis X 10 . It is this mechanism that is described below and that is represented in  FIG.  4    and following. 
     Headrest  10  includes a first part  12  which, in the following, can also be referred to as the “fixed part”. 
     Typically, the headrest  10  includes a frame  14 , usually made of metal, to which the first part  12  is attached. This frame  14  includes two parallel rods  14 A and  14 C, intended to be pushed inside two holes provided in the upper part of the seat backrest (See  FIGS.  2  and  3   ). 
     Advantageously, rods  14 A and  14 C comprise notches (not shown) to adjust the headrest  10  in height with respect to the top of the backrest  8 . Since this type of height adjustment for headrest is very common, it is not described further. 
     Also, rods  14 A and  14 C are connected to each other in the upper portion by a crossbar  14 B (See  FIG.  6   ). 
     Preferably, and as shown in  FIGS.  4  to  6    for example, the fixed part  12  is a U-shaped metal sheet (with a flat bottom). The two branches of the U extend substantially vertically, while the bottom of the U is substantially horizontal. The bottom of the U, i.e. the transverse part of the fixed part  12 , is arranged at the bottom of part  12 . 
     Typically, the first part  12  is attached to the crossbar  14 B. Specifically, the bottom of part  12  is attached to the crossbar  14 B of the frame  14 , for example welded above it. Obviously, this is not the only way to fix these two parts together: Any other appropriate means of fixing can be used (crimping, gluing, etc.). 
     Headrest  10  also includes a second part  16  that can be rotated relative to the first part  12 . In the following, this second part  16  can also be referred to as the “moving part”. 
     In the example, the cushion  11  is fixedly attached to the second part  16  of the headrest  10 , i.e. the cushion  11  rotates at the same time as the part  16  (See  FIGS.  2  and  3   ). 
     Typically, the movable part  16  is articulated on the fixed part  12 . This means that the moving part  16  is articulated around a shaft  18  passing through the two parallel walls of the fixed part  12  (See  FIG.  4    for instance). This shaft  18  is centred on the rotation axis X 10  of the headrest. 
     Preferably, and as shown on  FIG.  6   , the second part  16  includes two distinct wings  16 A and  16 B arranged on either side of the fixed part  12 . 
     In the example, these two wings  16 A and  16 B are L-shaped. One of the legs of the L extends parallel to the branches of the U forming the fixed part  12 , while the other leg logically extends perpendicularly to it. Specifically, the perpendicular leg of each wing  16 A or  16 B is arranged on the front side, i.e. on the side of the driver&#39;s head in a mounted configuration. 
     Headrest  10  also includes a rod  20  for controlling the relative movement between the first part  12  and the second part  16 . The second part  16 , i.e. the movable part, has an opening  22  for receiving the rod  20 , which is oblong in shape and extends curvilinearly in length (i.e. in an arc). 
     Advantageously, the pivot axis X 10  of headrest  10  (and moving part  16 ) passes through the centre of curvature of opening  22 . 
     As shown on  FIGS.  13  and  14   , cavities (or recesses)  24  are provided along the opening  22 . Preferably, rod  20  is circular in cross-section and the cavities  24  (i.e. the recesses) of the opening are complementary in shape, i.e. circular in shape as well. 
     Preferably, there are two rows of recesses  24  (on each side then) extending along the opening  22 . 
     Advantageously, and as shown on  FIGS.  15  and  16   , rod  20  defines at least one transverse slot  26  on its radial surface, preferably in the shape of a flattened area (i.e. the bottom of slot  26  is flat). Precisely, these are two transverse slots  26  which are arranged diametrically opposite each other, respectively on the upper and lower side of rod  20 . The two transverse slots  26  are located at the same (axial) level along the rod  20 . 
     The rod  20  then includes two portions: A first portion of the rod  20  has a circular cross-section, while a second portion of the rod  20  has an oblong cross-sectional shape. 
     Rod  20  is movable between an adjustment position, shown in  FIGS.  14  and  16    in particular, in which rod  20  does not prevent relative rotational movement between the first part  12  and the second part  16  about the axis X 10  and a locked position, shown in  FIGS.  13  and  15    in particular, in which rod  20  is stuck (or trapped) inside one of the cavities  24  of the opening  22 , thus preventing relative rotational movement between the first part  12  and the second part  16 . 
     Typically, rod  20  defines a longitudinal axis X 20  (See  FIG.  15   ) and the movement of rod  20  between its adjustment position and its locked position is a movement along the axis X 20 , i.e. it is a translational movement (motion in a straight line without rotation or other deformation). This is visible on  FIGS.  15  and  16    in particular. 
     As shown on  FIG.  16   , headrest  10  includes in the example a push button  30  allowing a user to move the rod  20 , along its longitudinal axis, between its locked position and its adjustment position. This push button  30  protrudes to the side of the cushion  11 , so that it can be pushed in by the user. 
     Here, push button  30  is arranged at one (longitudinal) end of the rod  20 . Preferably, the button  30  is integral with the rod  20 , meaning that the button  30  and the rod  20  are in one single part. 
     In the example, and as shown on  FIGS.  12  and  15   , headrest  10  also includes a means  28  for returning the rod  20  to the locked position. Preferably, this return means  28  is an elastic return means, such as a spring. Typically, and as shown on  FIG.  15   , spring  28  is arranged between a flange  34  of the rod  20  and a support  32  (used as counter-support) attached to the fixed part  12 . 
     This support  32  is U-shaped. It is attached inside the fixed part  12 , against one of the parallel walls of part  12 . 
     In the example, spring  28  is a compression spring, i.e. it stores mechanical energy when compressed and therefore exerts a constant return force as long as it is held in the compressed position. 
     When the driver wishes to adjust the orientation of headrest  10 , i.e. the position of the headrest around the axis X 10 , he presses the push button  30  (as represented by arrow F 2  on  FIG.  16   ), which moves the rod  20  from the locked position ( FIG.  15   ) to the adjustment position ( FIG.  16   ). In this adjustment position, the two transverse slots  26  are axially at the same level as the opening  22  and each oriented radially towards a cavity  24 . This means that it is the second portion of the rod  20  (comprising an oblong cross-sectional shape) which is received in the opening  22 , so there is no obstacle to slide the rod  20  along the opening  22 . The user can then tilt the movable part  16  of the headrest (and the cushion  11 ) forward or backward, as represented by arrow F 1  on  FIGS.  10  and  14   . 
     Once the user has found the correct position, he releases the button  30 . The rod  20  then automatically returns to the locked position ( FIG.  15   ) under the return force of the spring  28 . In the locked position, it is the first portion of the rod  20  (comprising a circular cross-sectional shape) which is received in a cavity  24  of the opening  22  and a locking in position of the part  16  with respect to the part  12  is obtained. 
     It is to be understood that the present invention is not limited to the embodiment described above and illustrated in the drawings; Rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims. 
     For example, one could consider moving from the locked position to the adjustment position (and inversely) by moving the rod  20  around its longitudinal axis rather than pushing it. 
     Also, the first part  12  could be the moving part and the second part  16  the fixed part. 
     According to another embodiment not shown, only one transverse slot  26  could be provided on the rod  20 . In this respect, the opening  22  would include only one row of recesses  24 .