Reinforcement member for pivotable assembly

A reinforcement member for a pivotable assembly is provided, enhancing resistance to deflection of the componentry of the pivotable assembly when subjected to shear loading. The pivotable assembly is expressly suitable for use as a recliner for a motor vehicle seat, an inertia latch, etc or other device where precise alignment of componentry is critical. The pivotable assembly has a support bracket generally including a pair of support brackets for mounting other componentry of the pivoting assembly, a pivoting member pivoting on a pivot attached to the support brackets, and a reinforcement member attached to the pivot. In one preferred embodiment, the reinforcement member has a projection, optionally a unitary semi- pierce projection, which extends into and preferably abuts an opening in one of the support brackets. The edge of the opening acts as a stop, to participate in carrying impact loads and to resist excessive static loading. In another preferred embodiment, one of the support brackets has a projection extending into the plane of the reinforcement member. The edge of the projection presents a generally perpendicular face or contact surface to the reinforcement member and acts as a stop resisting deflection during static loading of the pivoting member.

FIELD OF THE INVENTION 
The present invention generally relates to mechanisms enhancing the load 
characteristics of a pivoting member, and more particularly to an enhanced 
design resisting loading in motor vehicle seat recliners and inertia 
latches. 
BACKGROUND 
Typical pivotable assemblies, such as seat recliners for adjustment of a 
seat back relative a seat base, include a pivoting member rotatable about 
a pivot attached to support brackets at pivot holes. The pivoting member 
may be an arm having a series of teeth and may be attached to a seat back. 
In certain designs, a pawl is also rotatably attached to the support 
brackets and has a series of teeth which releasably engage the teeth of 
the arm in a locked position. When the arm is attached to a seat back, the 
seat back itself can be locked in position until the teeth of the pawl 
disengage the teeth of the arm. Such disengagement is commonly produced by 
operation of a spring biased rotatable cam. The cam is normally biased by 
the spring into engagement with the pawl, holding the pawl against the 
arm. Rotation of the cam allows or forces the pawl teeth out of engagement 
with the teeth of the arm. 
In such precise recliner mechanisms it is important that the pivot points 
for each part: arm, pawl and cam, be dimensionally stable. When the 
recliner assembly is subjected to high loads, the pawl will remain engaged 
with the arm and the pivot will exert significant forces on the support 
brackets. Such forces tend to plasticly deform and elongate the pivot 
holes, potentially leading to partial arm/pawl teeth separation, reducing 
the load capacity. In addition, spatter or dirt can interfere with 
operation of the mechanism. It would be desirable to enhance the strength 
of the pivot points, particularly the arm pivot, as typically the highest 
moments are seen at the arm. 
One way to enhance the strength of the arm pivot is to increase the 
thickness of the support brackets, and/or increase the strength of the 
material, usually steel, used in the manufacture of the support brackets. 
However, it is desirable to make seat recliners as light as possible. 
Increasing the thickness of the support brackets adds weight and cost to 
the recliner. Increasing the strength of the steel adds cost to the 
recliner. These problems are especially true where so-called "remote 
release" recliners are used, in which a release mechanism is positioned 
closer to the front of a motor vehicle seat, typically requiring longer 
support brackets. 
Another way to enhance the strength of the arm pivot is to weld the pivot 
to the support brackets. However, welds can splatter and interfere with 
the componentry of the mechanism. Moreover, the heat generated by the weld 
can result in distortions in the components, potentially misaligning the 
teeth. 
In view of the foregoing, it is an object of the present invention to 
provide a reinforcement member for use on a pivotable assembly to reduce 
deflection of the pivoting assembly when the pivoting assembly is 
subjected to high loads. 
It is an additional object of the present invention to provide a pivotable 
assembly of enhanced strength that is of low cost and is easy to 
manufacture. 
It is yet another related object of the present invention to provide such a 
pivotable assembly that is highly reliable in operation and does not 
interfere with the other componentry of the mechanism. Additional objects 
of various preferred embodiments will become apparent from the following 
disclosure. 
SUMMARY 
In accordance with these and other objects, there is provided a pivotable 
assembly having support brackets, a pivot mounted between the support 
brackets at pivot holes, a pivoting member pivotable around the pivot and 
a reinforcement member rotationally fixed to the pivot and engaging a 
support bracket. The reinforcement member, also referred to here as a 
doubler, acts to enhance the strength of the pivoting member and of the 
pivotable assembly generally and to substantially reduce deflection. Use 
of a doubler rotationally fixed to the pivot reduces and in many 
applications eliminates the need to thicken the entire support bracket, or 
otherwise take steps to enhance its strength. In seats using seat 
recliners where the pivoting member is an arm attached to a seat back and 
pivoting on the pivot, a load generated on the seat back produces a moment 
on the pivot of the arm. To aid in preventing the shear force generated on 
the support brackets from causing deformation or failure, the doubler 
contacts one of the support brackets. Thus, the load generated by the 
moment is spread over not only the pivot on the support bracket, but also 
the doubler on the support bracket. 
In accordance with one aspect, the doubler is attached to the pivot and has 
a projection, preferably a semi-pierced projection. The semi- pierced 
projection extends into an opening in the support bracket. The section of 
the edge of the opening which receives the force during loading acts as a 
stop. Alternatively, the projection may be on one of the support brackets 
and may extend into the plane of the doubler. Here the projection 
preferably forms a surface which is generally perpendicular to the 
doubler, and acts as the stop as it contacts the doubler. 
In accordance with another aspect, the pivotable assembly may be a seat 
recliner for a motor vehicle. Recliners typically have first and second 
generally parallel support brackets, a pivot pin extending between the 
brackets and an arm pivotable about the pivot pin and having teeth at one 
end. A pawl is pivotable on the support brackets and has teeth which are 
engageable with the teeth of the arm. A cam is rotatable from a normal, 
locking position, forcing the pawl into engagement with the arm, to a 
non-locking position wherein the teeth of the pawl are not engaged with 
the teeth of the arm, allowing for comfort adjustment. Typically a spring 
biases the cam into the normally locking position, and a release mechanism 
such as a release lever can be used to overcome the force of the spring 
and rotate the cam to the non-locking position. A reinforcement member is 
provided as described above. Such reinforcement member may be attached to 
the pivot, contacting one of the support brackets at a stop, and thereby 
enhancing resistance to deflection when the arm is subjected to shear 
forces in its rearward position. 
In accordance with yet another aspect, an inertia latch is provided with a 
reinforcement member enhancing the load strength of an arm which is 
pivotable about the pivot pin over a travel range extending from a forward 
position to an adjustable rearward position. Preferably the reinforcement 
member has a semi-pierced projection extending into an opening in a 
support bracket. Alternatively, the support bracket has a projection which 
engages the reinforcement member when the arm is at one end of its travel 
range. 
In accordance with a further aspect, a seat is provided with a seat back 
pivotable relative a seat base, wherein the motion of the seat back is 
controlled by a recliner, and the recliner has a reinforcement member as 
discussed above to increase the resistance to deflection when subjected to 
shear stresses or similar loading produced on the seat back. 
From the foregoing disclosure and the following more detailed description 
of various preferred embodiments it will be apparent to those skilled in 
the art that the present invention provides a significant advance in the 
technology and an of pivotable assemblies including seat recliners. 
Particularly significant in this regard is the potential the invention 
affords for a low cost design enhancing resistance to forces received at 
the pivot point. Additional features and advantages of various preferred 
embodiments will be better understood in view of the detailed description 
provided below.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS 
It will be apparent to those skilled in the art, that is, to those who have 
knowledge or experience in this area of technology, that many uses and 
design variations are possible for the reinforcement members disclosed 
herein. The following detailed discussion of various alternative and 
preferred features and embodiments will illustrate the general principles 
of the invention with reference principally to a seat recliner suitable 
for use in a motor vehicle. A single reinforcement member or doubler is 
disclosed in the drawings, though it should be understood that more than 
one doubler may be used on a given pivotable assembly within the scope of 
this invention. Other embodiments suitable for other applications, 
including reinforcement members for inertial latches for motor vehicle 
seats, will be apparent given the benefit of this disclosure. 
Referring now to the drawings, FIG. 1 is perspective view of a motor 
vehicle seat 10 that uses a semi-pierced reinforcement member 40 in 
accordance with a first preferred embodiment. The seat 10 has a seat back 
12 which is pivotable relative a seat base 14. A seat recliner 20 is 
positioned on at least one side of the seat 10. The seat recliner 20 has 
support bracket means for supporting the other componentry of the recliner 
typically comprising first and second support brackets 50, 60 which 
preferably are two stamped metal plates. The second support bracket 60 may 
be affixed to the seat base 14, the first support bracket 50 can be 
affixed to the second support bracket by staked or spun rivets and/or 
pivots, including arm pivot 22. The pivot 22 typically is a rivet, 
although it may also be the shank portion of a bolt. Alternatively the 
support bracket means may have only one support bracket, for example in 
the case where the side of the seat acts as a mount for the componentry of 
the recliner. 
As seen in FIGS. 2-3, an arm 21 is preferably attached to the seat back 12. 
The arm is pivotable about the pivot 22, and has a series of teeth 23 at 
one end. This allows the seat back to pivot relative the seat base. The 
teeth 23 engage teeth 29 on a rotatable or pivotable pawl 24. The pawl 
pivots about a separate pivot pin and has teeth 29 normally engage the 
teeth 24 of the arm to lock the arm and the seat back 12 attached to the 
arm in a locking or latching position. A rotatable cam 25 urges the pawl 
into the locking position. Cam 25 pivots about a third pivot pin. 
Typically a spring 27 biases the cam 25 which in turn biases the pawl into 
locking engagement with the arm. A release mechanism, such as a release 
lever 28 connected by a linking rod 66 to the cam, may be employed. The 
cam may have a positive drive out feature 26 to assist gravity in 
disengaging the pawl teeth from the arm teeth. As the cam rotates away 
from the locking position, the positive drive out feature contacts the 
pawl and urges the pawl out of engagement with the arm. Thus, rotation of 
the release lever 28 overcomes the force of the spring 27 on the cam 25, 
pulling the cam out of engagement with the pawl 24, and the pawl 
disengages the arm 21, allowing for comfort adjustment of the vehicle seat 
10. 
Optionally, as shown in FIG. 3, a clock spring 31 may be mounted at one end 
on the pivot 22 and the other end on a rivet 32 or similar projection 
extending from the arm and placing a biasing force on the rivet 32 urging 
the arm towards the full forward position when the arm is not locked with 
the pawl 24. 
To withstand high loads on the seat back which are then transmitted to the 
recliner without adding addition thickness to the support brackets or 
welding the pivot to the support brackets, a reinforcement member or 
doubler 40 is employed. Isolated views of one preferred embodiment of the 
doubler are shown in FIGS. 4A-4B. The reinforcement member 40 may be 
mounted externally of the support bracket means, as shown in the drawings, 
or alternatively, the support bracket means may have a ballooned portion 
that extends around the reinforcement member. The reinforcement member 
does not regulate angular motion of the arm beyond reducing deflection of 
the pivot pin, nor does it move the other componentry of the recliner. Its 
purpose is to resist loading on the pivot to help prevent deformation of 
the support brackets 50,60 and misalignment of the arm/pawl teeth 23,29. 
In the preferred embodiment shown in FIGS. 2-4, the doubler 40 is seen to 
be a generally planar member positioned around thread width great is, the 
doubler has a length and width greater than its depth. Extending into an 
opening 43 of the support bracket 60 is a projection 42 of the doubler. 
Preferably the projection 42 is semi-pierced or lanced from the doubler, 
making it unitary with the doubler. The edge 44 of the opening 43 presents 
a generally perpendicular surface or stop preferably abutting the 
projection 42 of the doubler 40. Thus deflection of the components of the 
recliner is minimized when the recliner is subjected to shear loading. The 
moment on the pivot is withstood by not only the area that the pivot 22 
contacts the support brackets 50, 60, but also by the area that the 
projection 42 of the reinforcement member 40 contacts the edge 44 of the 
opening 43 in the support bracket. 
FIGS. 5-6 show an alternative embodiment of the reinforcement member 55 for 
a pivotable assembly. Here, the projection 53, instead of extending from 
the doubler into the plane of the support brackets, extends from one of 
the support brackets 60 into the plane of the reinforcement member 55. 
Preferably the projection is a semi-pierced portion of the support 
bracket. The edge 54 of the projection again presents a generally 
perpendicular stop or contact surface preferably abutting the 
reinforcement member 55. Resistance to deflection caused by loading is 
again enhanced by increasing the area that receives the load. 
Alternative seat recliner designs, such as rotary or "taumel" mechanisms 
which are known to those skilled in the art, may use reinforcement members 
to enhance resistance to loading such as those described above. 
In accordance with an alternative preferred embodiment, FIG. 7 shows a 
stand alone inertia latch 33 having a load reinforcement member 55 similar 
to the reinforcement member shown in FIGS. 5-6. The inertia latch 33 can 
be used in conjunction with a recliner on a motor vehicle seat. The 
recliner would be mounted on one side of the motor vehicle seat, and the 
inertia latch may be mounted on the other side. The arm 33 would be 
mounted to the seat back, and pivotably mounted on support brackets. The 
support brackets are mounted to the seat base. The inertia latch shown is 
bi- directional, that is, the pawl 34 and arm 33 have teeth 36,37 which 
engage one another when the motor vehicle seat is subjected to rapid 
changes in velocity in either a forward or rearward direction. 
As an aid to enhance resistance to load induced deflections while the teeth 
of the pawl are engaged with the teeth of the arm, a projection 53, 
preferably semi-pierced, extends from the support bracket 50 into the 
plane of the reinforcement member 55. The edge 54 of the projection 
presents a generally perpendicular contact surface or stop preferably 
abutting the reinforcement member 55, thereby resisting deflection induced 
by shear forces received by the pivot 22. 
From the foregoing disclosure and detailed description of certain preferred 
embodiments, it will be apparent that various modifications, additions and 
other alternative embodiments are possible without departing from the true 
scope and spirit of the invention. For example, pivotable assemblies as 
disclosed above may be used on seats using a recliner on one side and an 
inertia latch on the other side, or recliners on both sides, or the 
recliner and inertia latch mounted together on one side, etc. The 
embodiments discussed were chosen and described to provide illustration of 
the principles of the invention and its practical application to thereby 
enable one of ordinary skill in the art to utilize the invention in 
various embodiments and with various modifications as are suited to the 
particular use contemplated. All such modifications and variations are 
within the scope of the invention as determined by the appended claims 
when interpreted in accordance with the breadth to which they are fairly, 
legally, and equitably entitled.