Note: Descriptions are shown in the official language in which they were submitted.
35~
This invention relates` to improvements in backrest
inclination adjustment devices such as are employed, for example,
in vehicle seat assemblies.
The prior art is exempltfied by U.S. Patent No.
4,687,252, issued to Robert L. Bell, et al, on Au~ust 18, 198~,
which patent discloses the use oE a recliner mecllarlisln for a
vehicle seatback, wh.ich mechanism includes a coil spring clutch
which is selectively tighterled or loosened around an actuator
clutch drum surface to adjustably fix the reclined position of a
vehicle seatback. The coil spring clutch is controlled by an
actuator lever which selectively causes the coil clutch spring to
tighten or loosen around the actuator clutch drum. More
importantly, in relation to the present invention, a redundan~
positioning pawl is provided which redundant pawl prevents
unrestrained motion of the seatback member in the event of failure
of the coil spring clutch. The actuator lever is normally biased
by a spring means to an engaged position whereat the coil spring
clutch is tightened around the clutch drive surEace and whereat
the redundant positioning pawl directly interferes with a
structural member of the vehicle seatback, so as to restrain
forward or rearward rec}ining oE the seatback. ~ pivotally
mounted intermediate lever is intercorlrlected between the actuator
lever and the redundant positioning pawl so as to cause movement
of the redundant positioning pawl out of such interference when
the actuator lever is moved from the engaged position to a
disengaged position, thereby allowing for pivotal movement of the
backrest member over the seatrest member. Once a selected
backrest inclination angle is selected, the actuator lever is
released, whereby the aforementioned spring biasing means returns
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actuator lever to the engaged posi tiOII, Wi th consequential
locking of the se~tback melnber as aforesaid. '~'he redundant
positioning pawl is also spring biased towards interEerence with
a structural member of the seatback mel-llber. and, UpOII failure or
improper operation of the coil spring clutch actuator, such
biasing serves to move the redundant posit~oning pawl lnto
locking interference with said struc~ural melllber, thereby
preventing sudden reclining of the seat back under the weight o~
an occupant, with possible disastrous consequences.
lo While redundant reclining devices such as the Bell
device constitute a significant improvement over similar devices
not having a redundant locking feature, they nonetheless, have
serious safety shortcomings. Foremost among these is the fact
that the redundant locking mechanism may. upon failure of the
primary locking means, be accidentally moved by the seat occupant
to a disengaged mode, thus causing sudden and une~pected rearwar
tilting of the backrest member. ~s will be appreciated, this
could be particularly disastrous where the seat in question is
occupied by the vehicle driver. ~dditionally, it should be
2~ considered that in prior art devices such as Bell there may be no
indication to the seat occupant that the primary device has
failed. That is, such prior art devices may contirlue to operate
in what appears to the occupant to be a normal marlr~er, as the
seat occupant is able with such devices to release the actuator
lever from the engaged position and, re-ad~iust the inclination
angle of the backrest member, thereafter returning the lever to
the engaged position. In so doing he rllay not appreciate any
difference in the operation of the locking mechanism. The
operator may thus continue to use the vehicle seat in a
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potentially dangerous condition in which it was not designed to
be used. Even where th~ seat occupant realizes there is a
problem in the operation of the mechanislll, there is a tendency
to put off servicin~ of the device to a n~ore convenient time.
Moreover, some prior art redundant locking devices
are constructed so that the redundant locking mecharlislll can,
after Eailure of the primary locking mechanislll, be
accidentally disengaged by inadvertent movelllent of the
actuator lever, with subsequent uncontrolled reclining of the
lo backrest.
So it will be seen that all prior art inclination
adjustment devices, even those incorporating a redundant
locking feature, encourage continued usage under potentially
dangerous conditlons.
It is an object oE the present invention to provide
a device for controlled adjustment of the inclination of a
backrest of a vehicle seat assembly which device incorporates
a redundant safety locking Eeature and which device is both
simple to manufacture and to install.
It is a further object of the present invention to
provide an inclination adjustrnent device having a redundant
safet~ locking means which device gives notice to the seat
occupant of the failure oE the primary locking means through a
significant change in the mode oE operation of the device.
It is yet a further object of this invention to
provide an improved inclination adjustment device in which the
redundant safety locking means cannot be unintentionally
disengaged following failure of the primary locking means, so
as to prevent sudden and unexpected rearward inclining of the
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backrest melllber oE an occupied vehlcle sea~.
It is yet a further object oE the present invelltiorl to
provide an improved inclination adjustmellt device which, following
failure of the primary locking means, must be restore~ to its
full operating condition by servicing personnel be~ore unlocking
of backrest member, either intentiol~ y or accidentally, is
possible.
These and other objects oE the present invention will
become more apparent once the following description oE a
o preferred embodiment, described by way of example only, is read
with reference to the accolnpanying drawings.
In the drawings:
FIGURE 1 is a diagrammatic perspective view of a vehicle
seat assembly having an inclination adjustmellt device in
accordance with the present invention irlcorporated therein, the
backrest member being shown in the norlllal upright position;
FIGURE 2 is an exploded view of the inclination
adjustment device of Figure l;
FIGURE 3 is a side sectional view of the device of
Figure 2, with the locking mechanism tllereoE in an engaged
configuration: and
FIGURE 4 is a view similar to Figure 3, with the lockirlg
mechanism in a disenga~ed configuration so as to allow pivotal
movement of the seat back.
Figure 1 shows a typical vehicle seat assembly 10 of the
general type with which the invention may be ;used. Such a seat
assembly may be of the "bucket" type as illustrated, or may be of
the well-known multi-occupallt "bench" type. In the latter case,
it is prefer~ble to use one inclination adjustment device
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according to the inven-tion at each of the two sides of the "bench"
type seat assembly. With "bucket" type seat assemblies, it is
generally sufficient to use a single adjustment mechanism for each
seat assembly installed, as for example, in the ci~cled area 2 of
Figure 1, and the preferred embodiment will be described with
reference to such use, although it will be expressly unders-too~ by
those skilled in the art that specific vehicle seat applications
may call for the analagous use of two or more inclination
adjustment devices according to the invention with each vehicle
o seating assembly.
Vehicle seat assembly 10 oE Flgure 1 has a backrest
member 12 which is pivotally mounted with respect to a seat member
11. Seat member 11 comprises a seat support frame 13 which is
anchored by conventional means in a fore-aft adjustment mode to
the floor panels (not shown) of the vehicle and which is covered
in the usual-manner with upholstery materials 15. The backres-t
member 12 comprises a support frame 16 which is also covered in
the usual manner with upholstery materials 17.
The inclination adjustment device 18 of the invention
comprises a first hinge bracket (comprising an inner 28 and an
outer 30 hinge plate) which bracket is rigidly connected by any
known fastening means (not shown) to a free end 20 of the seat
support frame 13. A second hinge bracket 22 is provided with an
upper terminal aperture 24 dimensioned to receive a nut and bolt
(not shown) to rigidly secure the second hinge bracket 22 to the
support frame 16 of the backrest member 12. Other conventional
fastening means, such as rivets or spot welding, may be used with
equal facility. Alternatively, the second hinge bracket 22 may be
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integrally formed as a terminal portion of the support frame 16.
The first hinge bracket comprises the inner hinge plate
28 and the outer hinge plate 30, which pla-tes are substantially
congruen-t and arranged substantially parallel to one another. It
s will be seen from ~igure 2 that the inner 28 and outer 30 h:inye
plates are maintained at a defined operative distance ~rorll one
another by means of various shouldered rivets and spacing washers
as more fully described below.
The second hinge bracket 22 is pivotally mounted about a
lo pivot pin 26 between the inner 28 and outer 30 hinge plates so as
to be pivotally movable with respect to the first hinge bracket 19
so as to allow for tilting of the backrest member 12 over the seat
member 11. As best seen in Figure 2, the inner hinge pla-te 28 is
provided with a shouldered main hinge pin 26 of which the second
hinge bracket 22 is pivotally mounted by means of aperture 31
about a central portion 32 of the hinge pin 26 for pivotal
movement of the seat back as previously mentioned. A reduced
diameter end portion 34 of the hinge pin 26 rests in the fully
assembled condition in an aligned aperture 36 of the outer hinge
20 plate 30, with the shoulder portion 26a and the spacer elemen-t 38
serving to maintain operative clearances between the second hinge
bracket 22 and the inner 28 and outer 30 hinge plates of the ~irst
hinge bracket. The shoulder 26a could, instead of the integral
shoulder shown, take the form of a second spacer element.
The rotational angle through which the second hinge
bracket 22 may pivot in the rearward (reclining) direction is
limited by a shouldered guide pin 40 which has an intermediate
diametered portion 42 which portion slides within a control slot
44 formed in the second hinge bracket 22. In this manner, the
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control slot 4g defines the operative range of inclination o~ the back-
rest member 12. That is, when the backrest member 12 is in its fully
reclined position, further reclining pivotable movement is prevented
by contac-t of the intermediate diametered, portion 42 of the
shouldered guide pin 40 with the trailing end 41 of the control
slo-t 4~. The rotational angle through which the second hinge bracl~et
22 may pivot in the forward (inclining) direction is limi-ted by
contact of the intermediate diametered portion 42 of the shouldered
guide pin 4Q with the leading end g3 of the control slot 44.
The second hinge bracke-t 22 is formed adJacent its
terminal end 45 with a gear sector means 46, which gear sector
means interacts with a pinion 48 i.n the following manner. The
pinion 48 ~which comprises a "gear means" as used in the claims) is
mounted on the first hinge bracket by means of an axle pin 50 in
meshing engagement with the gear sector means 46 so as to rotate
around the pin 50 on pivotal movement of the second hinge bracket
22 about the main hinge pin 26. A first 52 and a second 54 locking
gears are similarly mounted on the axle pin 50 for rotation
therearound. The second locking gear 54 is of smaller diameter
than the first locking gear 52 and both are affixed to the pinion
48 in concentric relation therewith. Any conven-tional affixation
means may be used, such as radial keying, spot welding, etc, it
being understood that the pinion 48 and the first 52 and second 54
locking gears rotate together as a unitary structure upon driving
rotation by the gear sector means 46.
The first locking pawl 56 is pivotally mounted between
the inner 28 and outer 30 hinge plates of the first hinge bracket
by means of an axle pin 58 so as to be freely rotatable there-
about, between a first position in which the first loc]cing
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pawl 56 restrainingly enga~es the first lock:ing gear 52 by means of
a toothed head portion 60 of the first locking pawl 56 (this
position being shown in Figures 2 and 3) and a second posi-tion in
which the first locking pawl 56 is removed from such restraining
engagement (see Figure 4) so as to allow Eor free pivotal movemen-t
of the baclcrest member 17. It will be appreciated that ln the
first position illus-trated in Figures 2 and 3, the backrest member
17 is held against pivotal movement in either the fore or aft
directions and that, when the first latching pawl 56 is in its
seco~d position as shown in Figure 4, the backrest member 17 is
free to be moved piviotally in either the fore or aft directions to
the extent allowed by the shouldered guide pin 40 interac-ting wi-th
the central slot 44.
A second locking pawl 62 is pivotally mounted on the
first hinge bracket by means of the pivot pin 58 on which the first
locking pawl 56 is also mounted. In this manner, the second
locking pawl 62 is able to pivotally move, under conditions
described more fully below, between a first position (not shown) in
which it restrainingly engages the second locking gear 54 and a
second position ~indicated in all of -the Figures) in which it is
removed from such restraining engagement with the second locl~ing
gear 54, and bears upon a stop pin 63 protruding from the outer
hinge plate 30.
A handle means 64 is pivotally mounted on the first hinge
bracket by means of a pivot pin 66 spanning the space between the
inner 28 and outer 30 hinge plates of the first hinge bracket 19.
The handle means 64 has a handle extension member 68 which extends
towards the front edge of the seat member 11 to facilitate gripping
by an occupant of the seat assembly 10. The handle means
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64 is pivotaly moveable about the pivot p:in 66 between a first
position (illustrated in Figures 2 and 3) in which a cam portion 70
of the handle means 64 bears UpOII the head portion 60 of the first
locking pawl 56 so as to urge the first lockillg paw:L into the
aforementioned first position oE the locking position and a second
position (illustrated in Figure 4) in which the caln portion 70
bears upon a tail portion~ of the ~irst locking pawl 56 so as to
urge the first locking pawl into its second position, at whic}l
second position the head portion 60 is disengaged froln the first
locking gear 52.
A first spring means in the Eorm of a coil spring 72 is
mounted abou~ the axle pin 58 so as to be adapted to bias the
second locking pawl 62 towards the said first pOSitiOII thereof when
not prevented from doing so by the further mechanislll described
below. The coil spring 72 has a first hooked end portion 74 which
engages a pin 76 protruding from the second locking pawl 62 and a
second hooked end portion 78 which engages a notch 80 formed in the
underside of the second locking pawl 62 so as to provide for said
biasing.
A second spring means in the form of a coil spring 82 is
interconnected between an arm portion 8l~ of the ha11dle means 64 and
the near side of the second locking pawl 62 so as to norlllally bias
the hatldle means 64 to the Eirst position as showrl in Figures 2 and
3. Spring 82 is connected to the arm portion 84 by means of a pin
86 ~ffixed to the arm portion 84, and to the second locking pawl 62
by means of the pin 76. It will be appreciated that the second
spring 82 is of greater biasing strength than the first spring
means 72 so that it is able to overcome the biasing of the first
spring means 72 so as to bias the second locking pawl 62 to its
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respective second position. 'lhe second spring Ineans B2 IllUS t be
sufficiently strong to overcome the biasing of the Eirst spring
means 72 regardless of whether the halldle nlearls 6~ is in its
respective first (see Figure 3) or secon~ (see ~igure ~) position.
With the above arrangelllerlts, it w~ L be a~)preciated that,
when both springs 72 and 82 are Eully operative, the seat occupant
need only move the harldle means 64 frolll tlle lirst position shown in
Figure 3 to its second position as in ~igure 4 to release tlle Eirst
locking pawl 56 from engagemerlt Witll the first locking gear 52 to
lo efEect manual adjustment of the inclination oE the backrest member
12. The second locking pawl 62 is at all times during such normal
operation of the handle nleans 64 positioned substantially at its
respective second position by reason oE the overriding biasing
effect of the second spring means 82.
Upon failure of tlle second spring mearls ~2, the biasing
effect on the second locking pawl 62 toward its respective second
position is thereby lost, so that it can no longer override the
biasing of the first spring means 72. Under such conditions, the
second locking pawl 62 is biased by the first spring means 72 to
its first position whereat it restrainingly engages the second
locking gear 54 so as to hold the backrest melilber 12 against either
fore or aft pivotal movelllent. It will be appreciated that
msnipulation oE the handle means 64 by the operator, whether
accidental or intentional, will have no eEEect upon the restraining
engagemellt oE the backrest melllber 12 by the second locking pawl 62.
As engagement of the second locking gear 54 by the second
locking pawl 62 will be substantially instantarleous upon breakage
of the second spring means 82, the inclination of the backrest
member 12 will not change substantially so that the seat occupant
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will be largely unaffecte~, thereby avoi~ing t}-le potentially
dangerous consequences of such failure. Moreover, the seat
occupant will not be able to overcome the saLety locking by the
second locking pawl 62, so tha~ servicing by qualifie~ personnel
will be required before the incl:ination of the backrest mem~er 12
can be altered.
It will be understood t~lat the invelltion is not to be
limited to the exact construction shown and described, but that
various changes and modifications may be made without departing
from the spirit and scope of the invention as described ln the
appended claims. For example, a discreet second locking gear 54
need not be provided. Routine design charlges in placement and
operation of the second locking pawl 62 could be such that the
second locking pawl 62 engages the Eirst locking gear 52 upon
failure of the Eirst spring means 82. Moreover, the first
pawl 56 and second locking pawl 62 need not pivot about the same
pivot pin 58. Additionally, the Eirst spring means 72 and the
second spring means 82 need not engage a single pin 76 such as
shown in the drawings, but could engage separate pins affixed to
the second locking pawl 62. The Eirst hinge bracket 19 may be
attached to the seat support fraole 13 in any one oE the numerous
well known arrangenlents currently being used in the art and,
indeed, could be made an integral component of the seat support
frame 13. Lastly, it is well known in the art to incorporate a
separate "dumping" mechanism into the second hinge bracket 22 above
the level of the main hinge pin 26. Such dulhpirlg mechallism (not
shown) may be of the so-called inertial type, in which case the
second hinge bracket 22 would itself be of composite construction
having an additional upper pivot point ~not shown) about which the
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upper portion o~ the second hinc~e bracket 22 would pivot in amanner controlled by the dumpirlg mecharlistTl. Such adaptations are
well known ln the art and do not add inventive subject matter to
the present invention. ~dditionally, the axle pin 5~ could be
routinely converted into a drive axle for the pin:iorl ~8 and
extended to accommodate a rotary handle means Eor utilization by
the seat occupant. This feature would allow the seat occupant to
e~fect adjustment of the backrest melnber 12 by turning of the
rotary handle means, rather than by gripping and pushing the
bac~rest member 17, as is required in the preferred embodiment
shown. All of the above modifications to the preferred embodiment
shown are mere routine design modificatiorls which do not add
inventive subject matter over that claimed.
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