Abstract:
A headrest. In one implementation the headrest includes a moving part that is rotationally coupled to a fixed part between a rest position and an active position. A connection assembly connects the moving part to the fixed part. An articulation assembly is operably coupled to and between the fixed part and the moving and has a first configuration when the moving part is in the rest position and a second configuration when the moving part is in the active position. The headrest includes a drive device that is moveable between first and second positions. In the first position the drive device is decoupled from the articulation assembly so that the articulation assembly assumes the first configuration, when in the second position the drive device acts upon articulation assembly to cause the articulation assembly to assume the second configuration.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application relates to and claims priority to Spanish Patent Application Serial No. P201130829, filed May 23, 2011. 
     TECHNICAL FIELD 
     This invention relates to headrests for motor vehicle seats. 
     BACKGROUND 
     There are known headrests, known as active headrests, that comprise two parts, a fixed part and a moving part, the moving part being movable, in the event that the vehicle receives a rear impact, from a rest position, in which the moving part is attached to the fixed part, to an active position. In the active position, the moving part is separated from the fixed part and moved towards the occupant of the seat, thereby reducing the distance the head of the occupant travels until it is supported on the headrest, and thereby reducing the risk of the occupant suffering whiplash. 
     European Patent No. 1403133 B1 describes an active headrest with a padded body to cushion the impact on the head of the occupant of the vehicle. This padded body houses an actuation device and from the padded body project two rods that connect to the seat. The actuation device of the headrest comprises a fixed part and actuation means supported by the fixed part and adapted to be fitted to adjust the position of the padded body in relation to the rods. The fixed part supports connection means for the actuation means. The actuation means comprises a moving part in relation to the fixed part, which is adapted to support part of the padded body. Connection means connects the rods to the fixed part. 
     The actuation means also comprises levers and a pyrotechnic drive device. The levers are articulated at one end to the fixed part by means of its connection means, and at the other end to the moving part. The pyrotechnic drive device is connected to the fixed part and to the levers to make them rotate in relation to the fixed part. 
     SUMMARY OF THE DISCLOSURE 
     In one implementation a headrest is provided that comprises a fixed part, a moving part movable in relation to the fixed part from a rest position to an active position, at least one connection means or assembly that connects the fixed part and the moving part to determine the path and the position of the moving part, and a drive system that comprises a drive device connected to the fixed part, to drive and move the moving part in relation to the fixed part. The drive system also comprises an articulated device or assembly pivotally connected at its ends to the fixed part and to the moving part and with at least one pivoting intermediate connection, the drive device cooperating operationally with the articulated device. 
     In one implementation the drive system includes, in addition to the drive device, the articulated device/assembly, the drive device cooperates with the articulated device/assembly and not with the connection means/assembly that position the moving part, thereby separating and making the drive, and therefore the movement and displacement of the moving part in relation to the fixed part, independent from the path and final positioning of the moving part. 
     In the prior art the drive device is connected to the connection means, which are connected at their ends to the fixed part and to the moving part, so that on driving them, they make them rotate and in their circular travel they determine the path and final position of the moving part. 
     An advantage of the drive systems disclosed and contemplated herein is that it allows the moving part to be driven to its active position irrespective of the way of fixing the path and final position, thereby resulting in more flexible headrest manufacturing systems, with a greater range and a reduced final cost. 
     These and other advantages and characteristics of the invention will be made evident in the light of the drawings and the detailed description thereof. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic profile view of an implementation of a headrest with the moving part being in a rest position. 
         FIG. 2  shows a perspective view of the implementation of  FIG. 1 , the moving part being in a rest position. 
         FIG. 3  shows a perspective view of the implementation of  FIG. 1 , the moving part being in its active position. 
         FIG. 4  shows a profile view in a longitudinal cross-section of the implementation of  FIG. 1 , the moving part being in its active position. 
         FIG. 5  shows a perspective view in a longitudinal cross-section of the implementation of  FIG. 1 , the moving part being in its active position. 
         FIG. 6  shows a perspective view of an implementation of the drive device in a rest position. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 to 5  illustrate a headrest according to one implementation. In the implementation shown in  FIGS. 1 to 5  the headrest  1  comprises a fixed part  2 , a moving part  4 , at least one connection means/assembly  5  connected in a pivoting manner to the fixed part  2  and to the moving part  4 , and a drive system. The moving part  4  is movable in relation to the fixed part  2  from a rest position ( FIGS. 1 and 2 ) to an active position ( FIGS. 3 ,  4  and  5 ). 
     The connection means/assembly  5  comprises in this implementation, as can be seen in  FIGS. 2 and 3 , an upper arm  35  and two lower lateral connection means  10 . The upper arm  35  comprises two side levers  38 , one of the ends of each side lever  38  pivoting in relation to a respective shaft  39  disposed on the fixed part  2 , both shafts  39  being coaxial, and the other of the ends of each side lever  38  pivoting in relation to a respective shaft  40  of the moving part  4 , both shafts  40  being coaxial. The upper arm  35  also comprises a central body  41  by means of which both side levers  38  are connected to each other. 
     The lower connection means  10  comprise a guide arm  36  connected to the moving part  4  and a channel  37  disposed in the fixed part  2 . The moving part  4  is guided to the fixed part  2  by means of the connection between the guide arm  36  and the channel  37 , and the slope of the moving part  4  in its rest position, in its active position and at all the points of the path from the rest position to the active position is determined by the connection between the guide arm  36  and the channel  37 . The connection is defined by the design of the outline of the guide arm  36 , which fits with the height of the channel  37  for all the positions of the required path of the moving part  4 . The guide arm  36  also comprises a stopper  42  that is housed in one of the transverse holes of the guide arm  36 , and which delimits the furthest position of the moving part  4  in relation to the fixed part  2 . The guide arm  36  may have various transverse holes, so that a choice may be made between different final positions of the moving part  4  depending on the hole in which the stopper  42  is housed. As a result, with the design chosen for the guide arm  36  and the channel  37 , and with the selection of the position of the stopper  42 , the path and the final position of the moving part  4  is defined, thereby minimising the risk of the occupant of the vehicle suffering whiplash in the event of a collision. Inone implementation, the guide arm defines a curving path. 
     The drive system, as shown in  FIGS. 1 and 4 , comprises a drive device  7  that is connected in an attached manner to the fixed part  2 , and its sole function is to cause movement, in other words, it is used to drive and move the moving part  4  in relation to the fixed part  2 . The drive system also comprises an articulated device/assembly  8  that is connected in a pivoting manner at its ends to the fixed part  2  and to the moving part  4 , and is disposed with at least one pivoting intermediate connection  9 , the drive device  7  cooperating operationally with the articulated device/assembly  8 . 
     As a result, in one implementation the drive device  7  cooperates with the articulated device/assembly  8  and not with the upper arm  35  or with the lower lateral connection means  10 , which position the moving part  4 , as a result of which the drive, or in other words the movement of the moving part  4  in relation to the fixed part  2 , and the path that the moving part  4  takes and its final position separate from each other and become independent, which as described above, is achieved with the design of the upper arm  35  and of the lower lateral connection means  10 . 
     The articulated device  8  comprises in one implementation a first arm  11  connected in a pivoting manner at one of its ends to the fixed part  2  in relation to a shaft  43  and to the pivoting intermediate connection  9 , and a second arm  12  connected at one of its ends to the pivoting intermediate connection  9  and the other end pivoting in relation to a shaft  44  of the moving part  4 . In one implementation the second arm  12  opens into two parts in the area of the pivoting intermediate connection  9 , so that it holds in the connection the first arm  11 , as shown in  FIG. 5 . 
     As shown in  FIG. 6 , the drive device  7  comprises in one implementation a pyrotechnic drive device  13 , a support of the pyrotechnic drive device  14 , a drive plate  16  that is driven by the pyrotechnic drive device  13 , and a drive guide  15  that guides the drive plate  16 . In one implementation the pyrotechnic drive device  13  is supported in the support  14 , which is preferably a U-shaped metal piece, the support  14  being disposed in its base with a hole that enables the insertion and the support of the base of the pyrotechnic drive device  13 . In one implementation the support  14  is disposed in its body with connection members that allow it to be connected to the fixed part  2  of the headrest  1  and, as a result, the pyrotechnic drive device  13  is also connected to the fixed part  2 . In one implementation the pyrotechnic drive device  13  comprises a body  17 , in the interior of which there is disposed a pyrotechnic load, and a bolt or shaft  18  that may move from a rest position to a final position when the pyrotechnic load is activated on the arrival of an electric signal from a sensor after a collision has occurred. 
     In one implementation the drive guide  15  comprises a central body  19  that is disposed with connection members that allow it to be connected to the fixed part  2  of the headrest  1 . In one implementation the central body  19  is supported and is connected to the upper part of the body  17  of the pyrotechnic drive device  13 . In one implementation the drive guide  15  also comprises two side arms  20  that project out of the central body  19 . In one implementation the side arms  20  are disposed on their inner face  21 , along their length, with a flat area  22  fitted between two side notches  23  to guide the drive plate  16 . 
     In one implementation the drive plate  16  comprises two bodies  24  that fit in the inner faces  21  of the side arms  20  of the drive guide  15 , and a shaft  25  that is fitted between the two bodies  24 , to leave the central part  26  of it free. Each of the bodies  24  of the drive plate  16  comprises, on the lateral face facing the interior of the headrest  1 , a projection  27 , attached to the body  24 , with a substantially flat upper face  28 . 
     The drive device  7  thus defined is a simple unit to assemble, as the various pieces are combined with each other and fit into each other with simple movements, and it is a sufficiently rigid unit, as the connections are made by the fitting and the introduction of connection members. In one implementation this is achieved by the use linear walls and “T” into grooves. In addition the drive device  7  as a unit is firmly referenced to the fixed part  2  of the headrest  1  as it is securely connected to it. 
     As shown in the implementation of  FIG. 1 , when the headrest  1  is in its rest position, the fixed part  2  and the moving part  4  are connected and form a single compact body. In this arrangement the pyrotechnic drive device  13  is not activated, and the bolt/shaft  18  is in its rest position, in other words withdrawn inside the body  17  of the pyrotechnic drive device  13 . In this situation the drive plate  16  is in its low position in relation to the drive guide  15 , and the bolt  18  of pyrotechnic drive device  13  is positioned beneath the central part  26  of the shaft  25  of the drive plate  16 , close to the shaft  25  of the drive plate  16 . 
     In this rest situation of the headrest  1 , the articulated device  8  of the drive system is withdrawn, and the first arm  11  of the articulated device  8  is positioned above the upper area of the central part  26  of the shaft  25  of the drive plate  16 , close to the shaft  25  of the drive plate  16 . 
     In one implementation, as shown in  FIGS. 4 ,  5  and  6 , a retaining means/retaining mechanism connects the fixed part  2  and the moving part  4 , which prevent the headrest  1  from being opened manually, and its interior may be accessed and its various members handled. In one implementation the retaining means/retaining mechanism comprise two moving hooks  29  and a fixed hook  30 , the fixed hook  30  comprising a central body and two arms  33  that project out of the central body. The moving hooks  29  and the arms  33  of the fixed hook  30  are connected at intermediate areas of both in the direction facing the interior of the headrest  1 , in an area of connection  31 , when the headrest  1  is in the rest position. The moving hooks  29  are preferably metal pieces, and are connected at one end  32 , opposite to the area of connection  31 , to the moving part  4  of the headrest  1  by means of an elastic connection means. The fixed hook  30  is also preferably a metal piece that is connected at the sides of its central body to the side of the central body  19  of the drive guide  15  facing the interior of the headrest  1 , at connection members disposed for that purpose. The area of connection  31  is configured on both hooks, in this implementation, in a U shape, with the open area being narrower than the closed area, so that the U of the moving hooks  29  and of the side arms  33  of the fixed hook  30  may fit and maintain their connection. In this situation the headrest  1  forms a single compact body, with the fixed part  2  and the moving  4  part being connected inseparably by manual means. 
     In one implementation the moving hooks  29  comprise at the end facing the interior of the headrest  1 , and projecting out of the area of connection  31  with the fixed hook  30 , a substantially flat flange  34  that projects out and is supported on the upper face  28  of the projection  27  of the body  24  of the drive plate  16 . 
     When the headrest  1  is in its rest position, the fixed part  2  and the moving part  4  are connected and form a single compact body, the pyrotechnic drive device  13  is not activated, and the bolt/shaft  18  is in its rest position. In this situation the drive plate  16  is in its low position, and the central part  26  of the shaft  25  of the drive plate  16  is positioned over the end of the bolt  18  of the pyrotechnic drive device  13  and close to the end of the bolt  18 . In this same rest situation, the articulated device/assembly  8  is withdrawn, and the first arm  11  of the device is positioned above the upper area of the central part  26  of the shaft  25  of the drive plate  16 , close to the shaft  25 . 
     When a collision occurs, the pyrotechnic load of the body  17  of the pyrotechnic drive device  13  is activated on the arrival of an electric signal from a sensor. The bolt/shaft  18  is then activated and moves from the rest position to the active position, as shown in  FIG. 4 . In this movement between the two positions, two stages are contemplated and which occur in a continuous manner; a first stage in which the bolt/shaft  18  travels the distance that separates it from the central part  26  of the shaft  25  of the drive plate  16 , and in its movement, comes into contact with the shaft  25 , driving it and moving the drive plate  16 . With the movement of the drive plate  16 , its bodies  24  slide all the way along the flat areas  22  of the side arms  20  of the drive guide  15 . As the projections  27  of the bodies  24  are attached to them, they are also moved, and due to the fact that the flanges  34  of the moving hooks  29  are supported on the upper faces  28  of the projections  27 , the flanges  34  are also moved. Due to this movement, to the fact that the fixed hook  30  is connected to the drive guide  15  and that this is connected to the fixed part  2 , and to the fact that the moving hooks  29  and the side arms  33  of the fixed hook  30  are connected in an area of connection  31  with a U shape, the connection  31  is released and the fixed part  2  and the moving part  4  that formed a compact connection when at rest, are also released. 
     In the second stage, according to one implementation, the bolt/shaft  18  continues the movement and travels the distance that separates it from its final active position. Following the distance traveled in the first stage, the upper area of the central part  26  of the shaft  25  of the drive plate  16  comes into contact with the lower area of the first arm  11  of the articulated device  8  and pushes it, and drives and moves it as a result. Due to the driving action, as the first arm  11  of the articulated device/assembly  8  is connected in a pivoting manner at one of its ends to the fixed part  2  in relation to the shaft  43  and to the pivoting intermediate connection  9 , and the second arm  12  of the articulated device  8  is connected at one of its ends to the pivoting intermediate connection  9  and the other end pivoting in relation to the shaft  44  of the moving part  4 , the second arm  12  is also driven and tilts in the pivoting intermediate connection  9 . As a result, the moving part  4  is driven and displaced, and therefore made to move, it being moved in relation to the fixed part  2  from a rest position to an active position. 
     In known headrests the path and the final position of the moving part depends on and is related to the design of the drive device and the connection means, thereby making each headrest design unique, According to the headrests of the present invention, the drive system is not dependent on the type of headrest where it is to be applied, as it is providing drive and movement, and the path and final position of the moving part  4  is defined by the connection means  5  that connect the fixed part  2  and the moving part  4 , thereby achieving more flexible headrest manufacturing systems, resulting in a wider range and a reduced final cost. 
     As the drive device  7  is attached to the fixed part  2 , and as it is not directly connected to the connection means  5 , it is made possible that the bolt/shaft  18  in its rectilinear movement, from a rest position to an active position, activates various mechanisms, performing operations in a simple manner, making use of the path. In one implementation, for example, the drive device first of all activates the retaining mechanism of the headrest  1 , which must be released to enable the headrest  1  to reach the active position, and then drive the articulated device/assembly  8  to move the moving part  4  in relation to the fixed part  2  from a rest position to an active position. 
     Given that, according to some implementations, a pyrotechnic drive device  13  is used, the time in which the headrest  1  is deployed from its rest position to its active position is greatly reduced in relation to other known headrests that do not use this type of drive device, thereby enabling the moving part  4  of headrest  1  to position itself more quickly in its active position in the event of a collision.