U.S. patent application number 09/728206 was filed with the patent office on 2001-06-07 for mechanical headrest retraction with memory effect with a seat for a means of transport.
Invention is credited to Fischer, Harald, Malsch, Heiko, Risch, Peter.
Application Number | 20010002764 09/728206 |
Document ID | / |
Family ID | 7930979 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010002764 |
Kind Code |
A1 |
Fischer, Harald ; et
al. |
June 7, 2001 |
Mechanical headrest retraction with memory effect with a seat for a
means of transport
Abstract
A seat for a means of transport, in particular a vehicle seat,
comprising a seat part, a backrest, a backrest adjustment system
(1) which connects the backrest to the seat part and which permits
a forward pivoting of the backrest onto the seat part, a height
adjustable headrest which is displaceably guided via at least one
guide rod (10) in an associated guide receiver (11) in the
backrest, and retaining means (30, 31) which are effective between
at least one guide rod (10) and the associated guide receiver (11)
and through which the guide rod (10) is releasably fixable at
different heights against displacement, wherein, for avoiding a
collision of the headrest with the vehicle roof, the guide receiver
(11) for the guide rod (10) is formed so as to be retractable
together with the guide rod (10) opposite to the extension
direction (VI) of the headrest inwards into the backrest into a
recessed position and back out again while the guide rod (10) is
arrested by the retaining means (30, 31) relative to the guide
receiver (11); and wherein means are provided through which an
automatic inward movement of the guide receiver (11) is caused by
the forward pivoting of the backrest and an automatic outward
movement of the guide receiver (11) back into its original position
is caused when the backrest is pivoted back.
Inventors: |
Fischer, Harald;
(Unterensingen, DE) ; Malsch, Heiko; (Heiningen,
DE) ; Risch, Peter; (Mannheim, DE) |
Correspondence
Address: |
MacMillan, Sobanski & Todd, LLC
One Maritime Plaza, Fourth Floor
720 Water Street
Toledo
OH
43604
US
|
Family ID: |
7930979 |
Appl. No.: |
09/728206 |
Filed: |
December 1, 2000 |
Current U.S.
Class: |
297/410 |
Current CPC
Class: |
B60N 2/832 20180201;
B60N 2/829 20180201; B60N 2/20 20130101 |
Class at
Publication: |
297/410 |
International
Class: |
A47C 007/36 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 1, 1999 |
DE |
19957793.5 |
Claims
What is claimed is:
1. A seat for a means of transport, in particular a vehicle seat,
comprising a seat part, a backrest, a backrest adjustment system
which connects the backrest to the seat part and which permits a
forward pivoting of the backrest onto the seat part, a height
adjustable headrest which is displaceably guided via at least one
guide rod in an associated guide receiver in the backrest, and
retaining means which are effective between at least one guide rod
and the associated guide receiver and through which the guide rod
is releasably fixable at different heights against displacement,
characterised in that the guide receiver for the guide rod is
formed so as to be retractable together with the guide rod opposite
to an extension direction of the headrest inwards into the backrest
into a recessed position and back out again while the guide rod is
arrested by the retaining means relative to the guide receiver; and
in that means are provided through which an automatic inward
movement of the guide receiver is caused by the forward pivoting of
the backrest and an automatic outward movement of the guide
receiver back into its original position is caused when the
backrest is pivoted back.
2. A seat in accordance with claim 1 characterised in that at least
one force deflection system having a flexible force transmission
element is active between the backrest adjustment system and the
guide receiver for the retraction and/or extension of the guide
receiver.
3. A seat in accordance with claim 2 characterised in that the
force transmission element acts on the guide receiver in the
extension direction; and in that an elastic return device is
provided which acts on the guide receiver in the retraction
direction.
4. A seat in accordance with claim 2 characterised in that at least
one Bowden cable is provided as the force deflection system.
5. A seat in accordance with claim 4 characterised in that one end
of the inner cable of a Bowden cable is fixed to a stationary
backrest part and the associated end of its sleeve is fixed to the
guide receiver, or vice versa.
6. A seat in accordance with claim 5 characterised in that one end
of the sleeve of a Bowden cable is fixed to a stationary part of
the backrest adjustment system and the associated end of its inner
cable is fixed to a part of the backrest adjustment system movable
with the backrest when it is pivoted forwardly, with this end of
the inner cable being attached to the movable part of the backrest
adjustment system such that the Bowden cable is relieved when the
backrest is pivoted forwardly.
7. A seat in accordance with claim 6 characterised in that the end
of the inner cable at the backrest adjustment system side is
attached to a slide block which is displaceably guided between two
end positions in a slide track arranged on a stationary part of the
backrest adjustment system; and in that the slide block is moved
between its two end positions by a part of the backrest adjustment
system moved when the backrest is pivoted forwardly.
8. A seat in accordance with claim 7 characterised in that a
pressure element is arranged on the moved part of the backrest
adjustment system, said pressure element holding the slide block in
its end position, in which the Bowden cable is stressed, when the
backrest is in the upright position, and successively releasing the
slide block when the backrest is pivoted forwardly so that it can
move into its other end position.
9. A seat in accordance with claim 1 characterised in that a path
multiplier is arranged between the backrest adjustment system and
the guide receiver, said path multiplier translating a small pivot
angle of the backrest into a large path of the guide receiver for
the headrest.
10. A seat in accordance with claim 6 characterised in that a
multiplier ratio is selected such that a relatively small angle of
forward pivoting of the backrest already results in the full
retraction movement of a headrest, even of a fully extended
headrest.
11. A seat in accordance with claim 9 characterised in that the
multiplier ratio is selected such that it changes with the pivot
angle of the backrest.
12. A seat in accordance with claim 9 characterised in that two
Bowden cables are provided whose one end is in each case fixed to
the path multiplier and whose other end is fixed to the guide
receiver or the backrest adjustment system.
13. A seat in accordance with claim 12 characterised in that a
transmission is provided as the path multiplier and comprises two
coaxially journalled rotating wheels which are connected to one
another in a rotationally fixed manner and which have different
diameters, with the one end of the inner cables of the two Bowden
cables being respectively fixed in place on the periphery of the
wheels such that the inner cables of the two Bowden cables can be
wound onto and off the rotating wheels in opposite directions.
14. A seat in accordance with claim 1 characterised in that a
spring actuator is provided between the backrest adjustment system
and the guide receiver.
15. A seat in accordance with claim 1 characterised in that a
sleeve fixable in the backrest is provided in which the guide
receiver is displaceably guided.
16. A seat in accordance with claim 15 characterised in that one
end of the sleeve of a Bowden cable acts on the guide receiver and
the associated end of the inner cable of said Bowden cable acts on
the sleeve; and in that a spring is active between the sleeve and
the guide receiver, said spring loading the guide receiver in the
retraction direction.
17. A seat in accordance with claim 1 characterised in that an
abutment is provided for the lower end of the guide rod, said
abutment limiting the retraction movement of the guide rod and thus
of the guide receiver.
18. A seat in accordance with claim 1 characterised in that when
the guide receiver is retracted, the headrest is automatically
adjustable to a minimum height relative thereto.
19. A seat in accordance with claim 1 characterised in that the
guide receiver can be extended out of the backrest as part of an
active head support system together with the guide rod in the event
of a rear-end impact and into such a position that the headrest is
brought into a forwardly and upwardly displaced position.
20. A seat in accordance with claim 19 characterised in that the
guide receiver can be extended out of the backrest by outward
movement of the sleeve.
21. A seat in accordance with claim 10 charaterised in that the
small angle is about 15 degrees or less.
Description
[0001] The present invention relates to a seat for a means of
transport, in particular a vehicle seat, comprising a seat part, a
backrest, a backrest adjustment system which connects the backrest
to the seat part and which permits a forward pivoting of the
backrest onto the seat part, a height adjustable headrest which is
displaceably guided via at least one guide rod in an associated
guide receiver in the backrest, and retaining means which are
effective between at least one guide rod and the associated guide
receiver and through which the guide rod is releasably fixable at
different heights against displacement.
[0002] In two-door motor vehicles, the backrests of the front seats
are usually made to pivot forwardly to make it easier to get into
the back seats. In vehicles with a low height such as sports cars,
the headrest can come into contact with the vehicle roof or the sun
visor during this movement. The forward pivoting of the backrest
can be made more difficult or even prevented in this way. The set
height of the headrest can also be changed.
[0003] It is the object of the invention to provide a seat of the
kind initially mentioned in which these problems do not occur and
wherein in particular contact between the headrest and the vehicle
roof should be avoided during the forward pivoting of the
backrest.
[0004] This object is satisfied by the guide receiver for the guide
rod being formed so as to be retractable together with the guide
rod opposite to the extension direction of the headrest inwards
into the backrest into a recessed position and back out again while
the guide rod is arrested by the retaining means relative to the
guide receiver and by means being provided through which an
automatic inward movement of the guide receiver is caused by the
forward pivoting of the backrest and an automatic outward movement
of the guide receiver back into its original position is caused
when the backrest is pivoted back.
[0005] Due to the automatic inward movement of the guide receiver
while the backrest is pivoted forwardly, a low position of the
headrest is also achieved when this was previously set to a greater
height. Contact of the headrest with the vehicle roof during the
forward pivoting of the backrest can thereby be effectively
prevented. The headrest can be retracted so far until the headrest
contacts the upper side of the backrest, that is possibly further
than its lowest setting position in which the headrest still has a
small spacing to the upper side of the backrest. The amount the
headrest protrudes upwardly over the backrest is thereby reduced to
a minimum so that contact with the vehicle roof can also be avoided
with very low vehicles. The guide receiver is here also stopped via
the retaining means so that the set headrest height does not
change.
[0006] The inward movement of the guide receiver with the guide
rods being held in place by the retaining means with respect to the
guide receiver, at the same time ensures that the headrest position
does not change relative to the guide receiver during retraction.
When the guide receiver is again extended back into its starting
position, the previously set headrest position is therefore again
reached. Thus, no new setting is required. Nevertheless, the
setting capability of the headrest height is maintained without
restriction over the whole setting range.
[0007] In accordance with an embodiment of the invention, at least
one force deflection system having a flexible force transmission
element is active between the backrest adjustment system and the
guide receiver for the retraction and/or extension of the guide
receiver. A Bowden cable can in particular serve to move the guide
receiver inwardly and/or outwardly. Such a system requires little
construction effort and can be accommodated in the seat in a
space-saving manner. Moreover, due to the flexibility of the force
transmission element, it allows a combination with an active head
rest system in which the headrest is moved from its normal position
into a position displaced upwardly and forwardly in the event of a
rear-end impact.
[0008] The force transmission element preferably acts on the guide
receiver in the extension direction while an elastic return device
is provided which acts on the guide receiver in the retraction
direction. The construction effort is reduced by the use of an
elastic return device and the return force is advantageously
supported by gravity since the return device acts on the guide
receiver in the retraction direction, that is approximately in the
direction of gravity. The return element can be given lower
dimensions as a result. However, the reverse arrangement is also
possible.
[0009] It is also preferred for the one end of the inner cable of
the Bowden cable to be fixed to a stationary backrest part and for
the associated end of the sleeve of the Bowden cable to be fixed to
the guide receiver. A reverse arrangement is also possible here.
The other end of the sleeve of the Bowden cable is in particular
fixed to a stationary part of the backrest adjustment system and
the other end of the inner cable is fixed to a part of the backrest
adjustment system which is movable with the backrest when this is
pivoted forwardly, with this end of the inner cable being attached
to the movable part of the backrest adjustment system in such a way
that the Bowden cable is relieved when the backrest is pivoted
forwardly. This means that the Bowden cable is stressed at the
normal backrest position and its sleeve fixes the guide receiver in
its topmost position. When the backrest is pivoted forwardly, the
Bowden cable is relieved and the return element can move the guide
receiver into a recessed position.
[0010] In accordance with a further embodiment of the invention,
the end of the inner cable at the backrest adjustment system side
is attached to a slide block which is displaceably guided between
two end positions in a slide track arranged on a stationary part of
the backrest adjustment system, with the slide block being moved to
and fro between its two end positions by a part of the backrest
adjustment system moved by the backrest when this is pivoted
forwardly. A pressure element is in particular arranged at the
moved part of the backrest adjustment system, said pressure element
holding the slide block in its end position in which the Bowden
cable is stressed when the backrest is in its upright position and
successively releasing the slide block when the backrest is pivoted
forwardly so that the slide block can move into its other end
position.
[0011] The movement of the Bowden cable is advantageously limited
by the slide track. Together with the pressure element, the
advantage also results that the backrest has a freewheel mechanism
during pivoting forward. That is, the backrest can be completely
pivoted forwardly without any impediment by the Bowden cable even
when the inward movement of the guide receiver has already been
stopped. The slide block, namely, then comes to stop at its
position in the slide track and the pressure element moves away
therefrom. When the backrest is pivoted back, the pressure element
then acts on the slide block again from a certain inclination of
the backrest and moves it back into its starting position in which
the Bowden cable is stressed.
[0012] This is in particular of advantage when, in accordance with
a further embodiment of the invention, a path multiplier is
arranged between the backrest adjustment system and the guide
receiver, said path multiplier translating a small pivot angle of
the backrest into a large path of the guide receiver for the
headrest. With this embodiment, it can be achieved that a small
forward-pivot angle of the backrest, in particular an angle of
approximately 15.degree., already results in the complete
retraction of the headrest, even when set to its highest position.
It is thus reliably ensured that the headrest does not come into
contact with either the vehicle roof or a visor which may possibly
be turned down.
[0013] The transmission ratio can also be selected such that it
changes with the pivot angle of the backrest. The inward movement
of the headrest can thus be effected in a slower manner at the
start and/or end stage in order to protect the system components
against too great a strain.
[0014] Two Bowden cables are preferably provided whose one end is
in each case fixed to the path multiplier and whose other end is
fixed to the guide receiver or the backrest adjustment system. A
path multiplication between the pivot angle of the backrest and the
displacement path of the guide receiver can be realised in a very
simple manner in this way.
[0015] In accordance with a further embodiment of the invention as
a path multiplier, a transmission can in particular be provided
which comprises two coaxially journalled rotating wheels which are
connected to one another in a rotationally fixed manner, which have
different diameters to one another and where the one end of the
inner cables of the two Bowden cables is respectively fixed in
place on the periphery of said rotating wheels such that the inner
cables of the two Bowden cables can be wound onto and off the
rotating wheels in opposite directions. Such a step-up gear is low
in construction effort and reliable in operation in combination
with a Bowden cable.
[0016] In accordance with a further embodiment of the invention a
spring actuator can be provided between the backrest adjustment
system and the guide receiver. Excessive strain on the system parts
can also be avoided by such a spring actuator. It is also generally
possible with such a spring actuator as an alternative to the
arrangement with slide block and pressure element to compensate for
different headrest heights before retraction into the guide
receiver.
[0017] In accordance with a further embodiment of the invention, a
sleeve is provided in which the guide receiver is displaceably
guided and which is fixable in the backrest, with the guide
receiver in particular forming an inner sleeve into which a guide
rod is insertable and fixable at different heights and which is
itself displaceable in the outer sleeve stationary on the backrest.
A compact arrangement with a reliable function can be provided in
this way.
[0018] One end of the sleeve of a Bowden cable preferably acts on
the guide receiver and the associated end of the inner cable of
said Bowden cable acts on the sleeve, with a spring acting between
the sleeve and the guide receiver and loading the guide receiver in
the retraction direction. This results in a system which can be
installed completely into a backrest of a vehicle seat, with the
sleeve being attachable to the backrest by conventional means, for
example by latching. The use of a sleeve ensures a reliable and
repeatable inward and outward movement of the guide receiver.
[0019] In accordance with a further embodiment of the invention, an
abutment for the lower end of the guide rod is provided which
limits the inward movement of the guide rod and thus of the guide
receiver. In this way, the headrest can be moved into a desired
retraction position which is independent of the actual backrest
when the backrest is pivoted forwardly.
[0020] In accordance with a further embodiment of the invention,
the headrest is automatically adjustable to a minimum height while
the guide receiver is moving inwardly. This can be effected in
particular by the retaining means acting between the guide receiver
and the guide rod being made automatically releasable over a
certain range. For example, a mechanical latching in this range can
act only in one direction so that the guide receiver can still be
further retracted by a certain number of latch positions when the
headrest abuts its lowest position. It is achieved in this way that
when the headrest is extended again, it returns to at least a
height which ensures a sufficient protective effect for the greater
majority of the population.
[0021] In accordance with a further embodiment of the invention,
the guide receiver can be extended out of the backrest as part of
an active head support system together with the guide rod in the
event of a rear-end impact and into such a position that the
headrest is brought into a forwardly and upwardly displaced
position. The headrest retraction in accordance with the invention
can thus be advantageously combined with such an active head
support system which offers additional safety, with the guide
receiver preferably being extendable out of the backrest by an
outward movement of the sleeve. This requires little construction
effort and can be combined particularly well with existing active
head support systems.
[0022] Embodiments of the invention are shown in the drawing and
are described in the following. There is shown, in each case in a
schematic representation:
[0023] FIG. 1 a perspective representation of an arrangement in
accordance with the invention;
[0024] FIG. 2 a side view of a part of FIG. 1 in a magnified
representation;
[0025] FIG. 3 a detailed representation of another part of FIG.
1;
[0026] FIG. 4 a magnified representation of a further part of FIG.
1; and
[0027] FIG. 5 a partly sectioned representation of a further part
of FIG. 1.
[0028] FIG. 1 shows the substantial functional elements of a seat
in accordance with the invention, namely a backrest adjustment
system 1 comprising a first adjustment part 2 fixable to a seat
part (not shown), a second adjustment part 3 mounted pivotally
around an axis I on the first adjustment part 2 and a third
adjustment part 4 arranged pivotally around an axis II on the
second adjustment part 3, said third adjustment part 4 being
fixable to a backrest of a seat (also not shown). While the
backrest inclination can be set by a turning of the third
adjustment part 4 relative to the second adjustment part 3, the
turning capability of the second adjustment part 3 relative to the
first adjustment part 2 allows a pivoting forwardly of the backrest
down onto the seat part, said backrest being able to be fixed in
place in its upright position by releasable means (not shown).
[0029] The end of a Bowden cable 5 is attached to the second
adjustment part 3 in the manner shown in detail in FIG. 2. The
other end of the Bowden cable 5 is connected to a step-up gear 6
which is shown in more detail in FIG. 3. The one end of a second
Bowden cable 7 is furthermore connected to the step-up gear 6, with
the other end acting on a headrest of which here only the two guide
rods 9, 10 are shown which are connected to one another via a
transverse brace 8. While the first guide rod 9 of the headrest is
received in a guide (not shown) in the backrest of a seat in a
conventional manner, the second guide rod 10 engages into a guide
receiver 11 which is displaceably guided in a sleeve 12 in the
direction of its longitudinal axis III, as shown in detail in FIGS.
4 and 5.
[0030] As can be seen in particular in FIG. 2, a slide 13 is
provided at the first adjustment part 2 of the backrest adjustment
system 1 and comprises a slide track 14 in which a slide block 15
is inserted. One end of the inner cable 16 of the first Bowden
cable 5 is attached to the slide block 15, while the associated end
of the sleeve 17 of the Bowden cable 5 is connected to the slide 13
at the one end of the slide track 14. Furthermore, a free end of a
return plate 18 attached to the second adjustment part 3 acts on
the slide block 15 in the extension direction IV of the inner cable
16. The inner cable 16 of the Bowden cable 5 is thereby moved
between a pulled-out and a non-pulled position when the second
adjustment part 3 is pivoted.
[0031] The other end of the sleeve 17 of the Bowden cable 5 is, as
is shown in FIG. 3, attached to a first inlet opening 19 of the
step-up gear 6. The associated end of the inner cable 16 of the
Bowden cable 5 is led through the opening 19 and fixed to a first
rotating wheel 20 such that the inner cable 16 is wound onto or off
the periphery of the first rotating wheel 20 when the rotating
wheel 20 is rotated around the axis of rotation V.
[0032] A second rotating wheel 21 is rotationally fixedly connected
to the first rotating wheel 20 is mounted pivotally around the same
axis V and has a greater diameter than the first rotating wheel 20.
The one end of the inner cable 22 of the second Bowden cable 7 is
fixed to the second rotating wheel 21 such that the second inner
cable 22 is wound onto or off the periphery of the rotating wheel
21 when the rotating wheel 21 is rotated around the axis V, said
winding on or off being in the opposite direction to the winding of
the first inner cable 16 on the first rotating wheel 20. The sleeve
23 of the second Bowden cable 7 is supported in this at a second
through passage 24 via which the inner cable 22 of the second
Bowden cable 7 is guided into the transmission 6. As can be seen,
pulling the inner cable 16 of the first Bowden cable from the first
rotating wheel 20 results in a winding up of the inner cable 22 of
the second Bowden cable 7 due to the opposite winding orientation,
with the wound up length of the inner cable 22 being larger than
the pulling off length of the inner cable 16 of the first Bowden
cable 5 corresponding to the different diameters of the two
rotating wheels 20 and 21. This results in the realisation of a
path multiplication between the first Bowden cable 5 and the second
Bowden cable 7 which is, for example 3:1.
[0033] The other end of the sleeve 23 of the second Bowden cable 7
acts on the guide receiver 11 for the second guide rod 10, as can
be seen in particular in FIGS. 4 and 5. The guide receiver 11
resting in the sleeve 12 has a nose 25 for this which extends
through an elongate opening 26 in the wall of the sleeve 12 and
which is provided with a passage aperture 27 through which the
inner cable 27 of the second Bowden cable 7 extends whose second
end is attached to a bead 28 at the upper end of the sleeve 12. The
nose 25 thus forms an upper abutment for the movement of the guide
receiver 11 in the sleeve 12.
[0034] Furthermore, a tension spring 29 acts on the nose 25 and is
supported at its other end on the lower end of the sleeve 12. In
FIG. 4, the tension spring 29 is shown purely schematically outside
the sleeve 12 in order to illustrate its function. In actual fact,
however, the tension spring 29 is located inside the sleeve 12.
[0035] The guide receiver 11 is biased in the direction of the
lower end of the sleeve 12 by the tension spring 29. The movement
of the guide receiver 11 in the sleeve 12 in the direction of its
longitudinal axis III is downwardly limited by the sleeve 23 of the
second Bowden cable 7 which acts on the nose opposite to the force
of the tension spring 29. The guide receiver 11 can only move
downwardly by so far as the inner cable 22 is released by the
transmission 6.
[0036] The sleeve surface of the guide rod 10 displaceably guided
in the guide receiver 11 has latch recesses 30 into which latching
means 31 are latchable which are arranged in the upper end region
of the guide receiver 11, with the latching means 31 being
unlatchable from the latch recesses 30 against the force of a
return device via actuating means (not shown). In this way, the
guide rod 10 can be adjusted in height relative to the guide
receiver 11 in order to set a desired headrest height.
[0037] Whereas the four bottommost latch recesses 30 are designed,
as can be seen in FIG. 5, such that they block a movement of the
guide rod 10 both in the extension direction VI and in the
retraction direction VII, the two topmost latch recesses 30 in the
guide rod 10 are formed such that the latching means automatically
unlatch when a force is applied to the guide rod 10 in the
extension direction VI or to the guide receiver 11 in the
retraction direction VII, but block in the opposite direction. As a
result, the guide rod 10 can automatically be notched up by two
latch stages via an abutment 32 on the lower end of the sleeve 12
when the guide rod 10 is located in its lowest position relative to
the guide receiver 11 as this moves inwardly. If it is already
notched up one stage, it is only notched up a further one stage
during retraction. The abutment 32 is not active in any other latch
stages.
[0038] The operation of the apparatus presented is as follows: The
tension spring 29 loads the guide receiver 11 in the retraction
direction VII, whereby the second Bowden 7 cable is stressed. The
tension of the second Bowden cable 7 is transmitted to the first
Bowden cable 5 via the step-up gear 6, with said first Bowden cable
5 being fixed by the return plate 18. The whole system is therefore
under the stress of the tension spring 29.
[0039] If the backrest of the seat is now pivoted forwardly down
onto the seat part, then the second adjustment part 3 of the
backrest adjustment system 1 pivots around the axis I relative to
the first adjustment part 2 and takes the return plate 18 along
with it whose free end moves away from the slide block 15 opposite
to the direction IV. Due to the tension of the tension spring 29
acting on the first Bowden cable 5, the inner cable 16 of the first
Bowden cable 5 pulls the slide block 15 along the slide track 14
behind the return plate 18. The retracted length of the inner cable
16 allows the step-up gear 6 to rotate around the axis V, whereby
the inner cable 16 is wound onto the first rotation wheel 20 and
the inner cable 22 of the second Bowden cable 7 is wound down off
the second rotating wheel 21. The tension spring 29 can displace
the sleeve 23 of the second Bowden cable 7 in the retraction
direction VII corresponding to the length of the inner cable 22
wound off and take the guide receiver 11 along while doing so. The
guide rod 10 of the headrest latched with the guide receiver 11 is
moved into the sleeve 12 together with the guide receiver 11 so
that the headrest is lowered.
[0040] If the backrest is fully pivoted forwardly downwardly, the
movement of the inner cable 16 of the first Bowden cable 5 is
limited by the end of the slide track 14. The inward movement of
the guide receiver 11 is also limited in this way via the released
length of the inner cable 22 of the second Bowden cable 7. This end
position is preferably reached already after a pivot angle of the
backrest of approximately 15.degree.. That is, the slide block 15
abuts the end of the slide track 14 already after a pivoting of the
backrest of only 15.degree. and the guide receiver 11 is completely
retracted due to the multiplication of the step-up gear 6.
[0041] When the back rest is pivoted back again, the second
adjustment part 3 pivots back around the axis I into its starting
position. The return plate 18 moved along with this motion again
comes into engagement with the slide block 15 at the end of the
movement and displaces it along the slide track 14 into its
starting position. The inner cable 16 of the first Bowden cable 5
is pulled out of its sleeve 17 by the slide block 15 so that the
inner cable 16 is pulled down from the first rotating wheel 20 of
the step-up gear 6. The first rotating wheel 20 is thereby set into
rotation around the axis V, with the second rotating wheel 21 in a
fixed connection to the first rotation wheel 20 being turned along.
As a result of the opposite direction of winding of the inner cable
16 of the first Bowden cable 5 and the inner cable 22 of the second
Bowden cable 7, the inner cable 22 of the second Bowden cable 7 is
wound onto the second rotating wheel 21 when the inner cable 16 is
wound off. Consequently, the sleeve 23 of the second Bowden cable 7
is displaced in the direction of the other end of the inner cable
22 of the second Bowden cable 7, with the sleeve 23 taking along
the nose 25 of the guide receiver 11 which is thereby also moved
into its starting position in which the nose 25 abuts the upper end
of the elongate recess 26. The guide rod 10, latched with respect
to the guide receiver 11, is also moved into its starting position
with the guide receiver 11 and the headrest is moved out to its
original height.
[0042] The initially set height of the headrest is therefore
maintained during the retraction and the repeated extension of the
headrest. In the variant shown in FIG. 5, the headrest is only
notched up one or two latch positions when it is located in the
lowest or second-lowest latch position and the backrest is pivoted
forwardly downwardly, that is the guide receiver 11 is moved
inwardly. However, it is also possible to omit this upward notching
so that the headrest set to the lowest or second-lowest position
also extends again into this position.
[0043] With a seat having an active head support system, the
headrest can be extended into a position upwardly and forwardly
displaced in a conventional manner in the event of a rear-end
impact despite the retraction apparatus in accordance with the
invention. This is made possible by the use of a force deflection
system with a flexible force transmitting element for the
retraction and/or repeated extension of the headrest. This namely
allows an enlargement of the distance between the headrest and the
actuating system at the backrest adjustment system. In the
embodiment shown, only the Bowden cables 5 and/or 7 must have a
corresponding length.
[0044] To avoid excessive stresses, the Bowden cable 5 can be
provided with a spring actuator. This also makes an adjustment of
the Bowden cables unnecessary.
[0045] The invention provides a seat with a headrest which is
automatically retractable when the backrest of the seat is pivoted
forwardly in order to avoid a collision with the vehicle roof or a
sun visor. The design is simple and advantageously effects a return
of the headrest to its originally set height. The system therefore
has a memory function for the headrest height. The system can
advantageously also be used with seat having an active head support
system. The normal adjustment of the headrest height can be carried
out manually or automatically, in particular electrically.
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