Double articulation for the folding backrest of a rear seat for motor vehicles and motor-vehicle seat including the articulation

A rear seat for a motor vehicle includes a squab, the front of which is articulated to the motor-vehicle body, and a backrest connected to the body. The backrest can adopt a vertical position of normal use, a first lowered position in which it bears on the squab. and a second lowered position in which it bears directly on the floor after the squab has been pivoted forwards. A double articulation which enables the backrest to be put into these positions includes two articulation pins connected rigidly to the backrest and an S-shaped body which is carried by the vehicle body and whose two sides define two guide tracks with arcuate profiles which are engaged by the two pins.

DESCRIPTION 
1. Field of the Invention 
The present invention relates to articulations for the folding backrests of 
rear seats for motor vehicles. 
2. Prior Art 
A double articulation for the folding backrest of a motor-vehicle rear seat 
is already known in the art, 
the seat including a seat element or squab the front of which is 
articulated to the body of the vehicle about a transverse axis so as to be 
movable between a position of normal use adjacent the floor and a 
substantially vertical position into which it is pivoted forwardly, and 
the articulation being intended to connect the lower portion of the 
backrest to the motor-vehicle body and including a first transverse 
articulation pin and a second articulation pin parallel to and spaced 
downwardly of the first so that the backrest can selectively adopt: 
a substantially vertical position of normal use, 
a first lowered position in which the backrest bears on the squab and which 
can be attained as a result of the forward pivoting of the backrest about 
the first articulation pin, and 
a second lowered position in which the backrest bears directly on the floor 
and which ca be attained by arranging the squab in its substantially 
vertical position and then pivoting the backrest forwardly about the 
second articulation pin. 
The movement of the backrest to one of the lowered positions increases the 
volume of the luggage compartment of the motor vehicle, the volume being 
greatest when the backrest is in its second lowered position in which its 
rear surface constitutes a substantially coplanar extension of the load 
platform. 
A double articulation of the type indicated above is described in French 
patent application FR-A-2 605 565. In this known solution, the backrest is 
connected to the body with the interposition of a connecting member 
articulated both to the backrest and to the body by means of the first and 
second articulation pins respectively. This solution is quite complex 
since it also includes resilient means which oppose the pivoting of the 
articulation between the backrest and the connecting member, as well as 
remotely-releasable means for locking the articulation between the 
connecting member and the body. 
OBJECT OF THE INVENTION 
The object of the present invention is to provide an articulation of the 
type indicated above which has a simple structure and is constituted by 
fewer parts, to the benefit of its manufacturing costs and reliability in 
operation. 
THE INVENTION 
According to the invention, this object is achieved, by virtue of the fact 
that: 
the first and second articulation pins are both fixed to the backrest of 
the seat and are both free to move relative to guide means which are 
intended to be fixed to the body, 
the guide means include first and second guide tracks for the first and 
second articulation pins respectively, the first and second guide tracks 
being shaped as arcs of circles centred on the axes of the second and 
first articulation pins respectively, with reference to the base positions 
of the pins when the backrest is in the vertical position, 
the guide tracks also have respective ends with stop surfaces which define 
the base positions of the two articulation pins when the backrest is in 
the vertical position, 
whereby the backrest can pivot about the first articulation pin to move to 
its first lowered position, in which case the first articulation pin 
remains in its base position and the second articulation pin moves away 
from its base position along the second guide track, or about the second 
articulation pin to move to its lowered position, in which case the second 
articulation pin remains in its base position and the first articulation 
pin moves away from its base position along the first guide track, and 
means are provided for restraining the first articulation pin in its base 
position when the squab is in its position of normal use. 
The advantages which can be achieved by the present invention consist 
essentially of the fact that an articulation thus formed includes a 
limited number of mechanical components, to the benefit of its reliability 
in use; this results in a considerable reduction in the time and materials 
needed for the assembly of the seat with a consequent reduction in costs. 
The invention also relates to a motor-vehicle rear seat including an 
articulation having the characteristics specified above.

DESCRIPTION OF A FIRST EMBODIMENT OF THE INVENTION 
With reference initially to FIGS. 1 and 7, a rear seat for a motor vehicle, 
generally indicated 1, includes a squab 2 and a backrest 5. 
The squab 2 bears on the floor 3 of the body and, near its front end 2a, 
includes a transverse articulation pin 4 for enabling the squab 2 to pivot 
until it reaches a vertical position (FIGS. 2 and 9). 
In FIGS. 1 and 7, the backrest 5 is in a substantially vertical position of 
normal use and its lower end 5a is connected to the motor-vehicle body on 
each side by an articulation, generally indicated 6. 
The articulation 6 includes two parallel transverse pins, an upper pin 8 
and lower pin 9, fixed to the structure of the backrest 5 and a body 10 
fixed to the body of the vehicle for guiding the pins 8 and 9, as will be 
described in greater detail below. 
The backrest 5 is kept in its position of normal use by a fixing device 7 
of known type arranged near its upper end 5b and comprising, for example, 
a hook 7a adapted to grip a pin 7b projecting inwardly from the side of 
the motor-vehicle body. The structure of the device 7 is not shown in 
detail since, as already indicated, this device may be of any known type 
and does not fall within the scope of the present invention. Moreover, the 
fact that these details are left out of the drawings makes the latter more 
readily and easily understood. 
The device 6 enables the backrest 5 to be pivoted so as to rest either on 
top of the squab 2 (FIGS. 2 and 7) or, after the squab 2 has been pivoted 
forwards about the pin 4, directly on the floor 3 of the body so as to 
constitute an extension of the rear load platform 3a (FIGS. 3 and 8). 
As shown in greater detail in FIGS. 4, 5 and 6, the guide body 10 is shaped 
substantially like a reversed S and includes a metal core 10a incorporated 
in a plastics body 10b including a support plate 11 with holes 18 (only 
one of which is shown) for the engagement of screws, not shown, for fixing 
it to a vertical portion of the body beside the backrest 5. 
The two sides of the S-shaped body define two guide tracks 14 and 15 the 
ends of which have respective stop surfaces in the form of circular seats 
12 and 13 having axes 12a and 13a lying in a transverse plane 
substantially perpendicular to the floor 3 of the motor vehicle. The guide 
tracks 14 and 15 have circular profiles whose centres of curvature 
coincide with the axes 13a and 12a respectively (see in particular FIG. 
4). The end of the pin 8 has an enlarged head forming an annular 
projection 16 which is partially engaged in a groove 17 (FIG. 5) adjacent 
the track 14 so as to prevent the backrest 5 from moving sideways relative 
to the motor-vehicle body. 
When the backrest 5 is in its position of normal use, the pins 8 and 9 are 
in their base positions engaged in the seat 12 and the seat 13 
respectively (see FIG. 4). The squab 2 has a stop member 2b which is in 
contact with the pin 8 when the squab is in its normal position, so as to 
prevent the pin 8 from moving away from its base position. Moreover, the 
body 10 has a resilient blade 130 which is resiliently deformed by the pin 
9 when it moves from its base position. 
By virtue of the shape of the element 10, when the pin 8 is in its base 
position, the pin 9 can move along the track 15 following an arcuate path; 
similarly, when the pin 9 is in its base position, the pin 8 can move 
along the track 14 following an arcuate path about the pin 9. 
In operation, in order to move the backrest 5 to its first lowered 
position, the hook 7b is released from the pin 7a and the top 5b of the 
seat is pushed forwards. Since the squab is in its normal position with 
the stop member holding the pin 8 in the seat 12, the backrest 5 can pivot 
only about that pin, overcoming the opposition of the blade 130. The 
backrest 5 stops when it bears on the squab 2 (FIGS. 2 and 8). During the 
movement of the backrest, the pin 9 slides along the guide track 15. The 
backrest can be returned to its erect position in a similar manner. 
In order to move the backrest 5 to its second lowered position, the squab 2 
is first pivoted about the pin 4 until it is arranged vertically as shown 
in FIGS. 3 and 9. In this configuration, the backrest no longer meets any 
resistance from the stop member 2b of the squab 2 and, if its top is 
pushed after the fixing device 7 has been released, it pivots about the 
lower pin 9 which is restrained by the resilient blade 130. 
The articulation 6 described specifically in this description and 
illustrated in the appended drawings includes a flat, reversed-S-shaped 
element 10 for association with the right-hand side of a seat backrest and 
of a motor car body, a similar S-shaped body for use on the left-hand side 
of the seat and the body, however, will have a shape symmetrical to that 
described. 
DESCRIPTION OF A SECOND EMBODIMENT 
FIG. 10 relates to a variant for a seat with a single squab and a backrest 
including two separate portions 5d which can be folded independently (only 
one of the portions 5d is visible in FIG. 10). In this embodiment, each of 
the outer sides of the backrest is connected to the body by means of an 
articulation 6. The facing sides of the backrest portions 5d, however, are 
connected to the body by a connecting device 60 which is indicated by the 
arrow XI in FIG. 10 and is shown on an enlarged scale in FIGS. 11 and 12. 
The device 60 comprises a bracket 61 fixed to the floor of the body and a 
connecting member 62 which is articulated to the bracket 61 and to the 
structures of both the right-hand and left-hand portions 5d of the 
backrest. With reference to FIGS. 11 and 12, the connecting member 62 has 
a U-shaped body 63 including a U-shaped, bent metal plate 64 covered in 
plastics material. The two arms 65 of the U-shaped body 63 have opposed 
pins 66 which engage respective holes 67 in the facing sides of the 
structures of the two backrest portions 5d (see FIG. 10, in which one of 
the holes is visible). The holes 67 are aligned on the axis 12a of the two 
side articulations 6. As already stated, the body 63 is also articulated 
to the bracket 61 by a pin 68. Finally, the body 63 also has two lateral 
guide tracks 69 which correspond to the tracks 15 of the articulations 6 
and which are engaged by two pins 90 (only one of which is visible in the 
drawings) carried by the two adjacent sides of the backrest portions 5d 
and aligned on the axis of the pin 9 of each articulation 6. If both of 
the backrest portions 5d are to be folded, the operation is similar to 
that described above with reference to FIGS. 8 and 9. If the squab is kept 
in its normal position, the connecting member 62 cannot move since the 
pins 66 are restrained by the backrest because the pins 8 are stopped by 
the squab. The backrest can thus be folded by being pivoted about the axis 
12a. The pins 9 slide along the tracks 15 and the pins 90 slide along the 
tracks 69 of the body 63. When the squab 2 is tipped up, both the backrest 
portions can be pivoted about the axis 13a. In this case, the connecting 
member 62 pivots relative to the bracket 61. If only one portion 5d, for 
example, the right-hand portion, that is, the one shown in FIG. 10, is to 
be folded, the squab 2 has to be kept in its normal position. The portion 
5d can thus pivot about the axis 13a, overcoming the opposition of the 
resilient blades 130 of the two lateral articulations 6. The pins 9 slide 
along the guides 15 whilst the pin 90 of the portion 5d which is lowered 
slides along its track 69. 
Naturally, the principle of the invention remaining the same, the forms of 
embodiment and details of construction may be varied widely, without 
thereby departing from the scope of the present invention.