Adjustable hinge

An adjustable hinge includes a first arm having a pivot pin rigidly mounted thereto and extending to one side thereof along an axis with a bearing element mounted on the other side of the arm. A second arm is mounted on the bearing element and includes an arcuate toothed rack coaxially aligned with the axis. An arm retention plate overlies the second arm for retention thereof on the bearing element and additionally entraps a toothed locking pawl which is mounted within the bearing element for selective radial movement into and out of engagement with the arcuate rack. The pawl is provided an arcuate slot therethrough which has one end thereof closer to the pivot pin than the second end. A pawl actuating device is pivotally mounted on the pivot pin and includes a pawl locating pin displaced from the axis to extend through the arcuate slot of the locking pawl. Additionally, the pawl locating pin extends through aligned slots in the first arm and the arm retention plate to provide support at opposite sides of the arcuate slot of the pawl during movement of the actuating device which produces the desired radial movement of the pawl.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to hinges for pivotally connecting the back frame of 
a vehicle seat and the cushion panel of a vehicle seat and, more 
particularly, to a releaseable locking device capable of being externally 
controlled for adjusting the angle of inclination of the back cushion 
relative to the seat cushion. 
2. Description of the Prior Art 
It is well known for the back frame of a vehicle seat to be adjustable in 
position relative to the cushion frame according to the requirements of 
the occupant. Although various types of hinge arrangements are known to 
permit such adjustment, a continuing need exists to provide such a hinge 
which is relatively inexpensive and capable of being reliably utilized 
throughout the life of the automobile. 
As generally disclosed in U.S. Pat. Nos. 3,309,139; 3,788,698; 3,848,923; 
3,897,608; 3,900,225; 3,902,757 and 3,931,996, there have been utilized 
seat hinges with lever actuated engaging means for selecting the relative 
angle of the hinge arms and for maintaining that angle according to the 
desires of the user. These devices typically include an extended lever arm 
which acts upon a pivotally mounted engaging element which is located 
remotely from the hinge axis. 
There are, however, other devices such as those disclosed in U.S. Pat. No. 
3,737,946 utilizing a different configuration which generally includes an 
arcuate rack associated with one arm of the hinge and a selectively 
engageable and disengageable pawl associated with the other arm of the 
hinge for selecting and maintaining the angle between the arms as desired. 
This device includes operating elements which are better protected and 
more compactly arranged than those discussed above. However, the means 
provided in this prior art device utilize camming surfaces to operate on a 
portion of the pawl in an unsupported, cantilevered fashion. Such an 
arrangement over the extended life of an automobile could result in 
bending or breaking of that portion of the pawl which is the primary area 
where forces are generated to produce this movement. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide an adjustable hinge for 
utilization between the back frame and cushion frame of a vehicle seat 
which is relatively simple to provide and capable of providing reliable 
operation throughout the life of the vehicle. 
To provide this and other objects of the invention a preferred embodiment 
thereof includes an adjustable hinge comprising a first arm, a pivot pin 
rigidly secured to the first arm to extend to at least one side thereof 
and a bearing element extending from the other side of the arm and having 
a first bearing surface lying at least partially within a cylindrical 
surface which is coaxially aligned with the pivot pin. A second arm has an 
opening therethrough which is at least partially defined by a second 
bearing surface generally matching the first bearing surface so that the 
bearing element can be received within the opening to mount the second arm 
for rotation relative to the first arm about the axis. The second arm 
includes an arcuate toothed rack coaxially aligned with the second bearing 
surface. An arm retention plate is fixedly mounted relative to the bearing 
element to overlie the second arm for retention thereof on the bearing 
element. A toothed locking pawl is mounted relative to the first arm in 
general alignment with the arcuate rack for radial movement with respect 
to the axis for selective engagement with and disengagement from the 
arcuate rack. The locking pawl has an arcuate slot therethrough which 
includes a first end which is closer to the pivot pin than a second end 
thereof. A pawl actuating device is pivotally mounted on the pivot pin and 
includes a pawl locating pin displaced a predetermined distance from and 
extending in a direction parallel with the axis to be commonly received 
within the arcuate slot of the pawl and matching, aligned slots through 
the first arm and the retention plate. Each of the aligned slots has an 
arcuate shape with an effective radius from the axis which is equal to the 
predetermined distance so that the first arm and the retention plate 
support the locating pin at the aligned slots therethrough at both sides 
of the pawl to distribute operating forces acting along the locating pin 
during movement of the pawl thereby.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
As seen in FIGS. 1-5, the preferred embodiment of the present invention 
includes an adjustable hinge 10 having a first arm 12 and a second arm 14 
adapted to be mounted for rotation of one with respect to the other about 
an operating axis 16. Each Each arm 12 and 14 includes a number of holes 
18 therethrough to facilitate mounting of the hinge respectively to the 
cushion frame and the back frame of, in the case of the preferred 
embodiment, the right or passenger seat of a vehicle (not shown). 
The preferred hinge 10 further includes a pivot pin 20 having a cylindrical 
first end 22 and an intermediate portion 24 having a squared cross 
section. The intermediate portion 24 of the pivot pin 20 is generally 
received within a square opening 26 of the first arm 12 during assembly to 
be retained therein as will be discussed further hereinbelow. With the 
pivot pin 20 so positioned relative to the first arm 12, the cylindrical 
end 22 thereof extends outwardly of a first side 28 of the first arm 12. 
Mounted against the other side 30 of the first arm 12 is a bearing element 
32 which is utilized to basically mount the second arm 14 for rotation 
relative to the first arm 12. A plurality of holes 34 through the first 
arm 12 and the bearing element 32 receives a plurality of rivets 36 for 
fixedly securing the element 32 to the arm 12. The bearing element 32 
includes a bearing surface 38 which includes at least a substantial 
portion thereof lying within a cylindrical surface which is coaxially 
aligned with the axis 16. A portion of the bearing surface 38 is removed 
without altering the support which it is capable of providing the second 
arm 14 and will be discussed in detail hereinbelow. 
To facilitate mounting of the second arm 14 relative to the first arm 12 at 
the bearing element 32, the second arm 14 includes a large opening 40 
therethrough having a peripheral mating bearing surface 42 extending about 
the majority of its diameter for sliding contact with the bearing surface 
38 of the element 32. To retain the second arm 14 adjacent the first arm 
12, a retention plate 44 is provided which also includes aligned holes 34 
for receipt of the previously mentioned rivets 36 to complete the rigid 
mounting of the first arm 12, bearing element 32 and retention plate 44. 
The retention plate 44 includes a central hole 46 therethrough for receipt 
of the second end 48 of the pivot pin 20 and has outer dimensions which 
cause it to overlie the second arm 14 to prevent its movement along the 
axis 16. 
As seen in FIG. 3, one circumferential section of the opening 40 includes 
an arcuate rack 50 having, in the preferred embodiment, an effective 
radius slightly larger than the bearing surface 42 to prevent interference 
of the teeth 51 thereof with the bearing surface 38 of the bearing element 
32 during relative movement of the second arm 14 with respect to the first 
arm 12. The arcuate rack 50 is provided on the second arm 14 to generally 
include a means for engaging the second arm 14 at a predetermined angle 
relative to the first arm 12 according to the desires of the seat 
occupant. The present invention includes a locking pawl 52 having a 
plurality of teeth 53 to provide a means relative the first arm 12 for 
selective engagement with and disengagement from the matching teeth 51 of 
the arcuate rack 50. 
In the preferred embodiment 10, the locking pawl 52 is mounted within a 
cavity 54 of the bearing element 32 to be capable of limited radial 
movement toward and away from the arcuate rack 50. Additionally, the pawl 
52 is provided an elongated opening 56 therethrough for receipt of the 
pivot pin 20 to facilitate assembly of the hinge 10 while still allowing 
the desired radial movement of the pawl 52 relative to the pivot pin 20. 
As can be seen from the view of the preferred hinge 10 in FIGS. 1 and 4, 
the retention plate 44 is also dimensioned to overlie the locking pawl 52 
to maintain it in general alignment with the rack 50 throughout use of the 
hinge 10. To produce the desired movement of the locking pawl 52 to ensure 
its selective engagement with and disengagement from the rack 50, an 
arcuate slot 58 is provided therethrough. The arcuate slot 58 has a first 
end 60 which is closer to the axis 16 throughout radial movement of the 
pawl 52 than is the second end 62. The arcuate slot 58 provides a camming 
surface which is adapted to receive a pawl locating pin 64 therethrough. 
To provide a means for control and support of the pawl locating pin 64, it 
is rigidly mounted to a pawl actuating device 66 which is operatively 
mounted adjacent the side 28 of the first arm 12. 
The pawl actuating device 66 includes a hole 68 therethrough adapted to be 
received around the cylindrical end 22 of the pivot pin 20. The pawl 
locating pin 64 is displaced a predetermined distance from and extends in 
a direction generally parallel with the axis 16 and is supported in its 
movement of the pawl 52 by being received within a pair of aligned slots 
70 and 72 which are respectively provided the first arm 12 and the 
retention plate 44. The slots 70 and 72 are arcuate in shape and have an 
effective radius from the axis 16 which is equal to the predetermined 
distance of the locating pin 64 from the axis 16. Accordingly, as the 
locating pin 64 rigidly extends from the pawl actuating device 66, it is 
aligned with and received within each of the slots 70 and 72 for general 
support thereof during its movement about the axis 16. Therefore, movement 
of the locating pin 64 causes radial movement of the pawl 52 as it acts on 
the arcuate slot 58 but the slots 70 and 72 ensure that it is supported 
throughout operation of the hinge to minimize the effect which could be 
produced by forces acting on the pin if it were simply extended in a 
cantilevered manner. 
As thus explained, there has been provided through the pawl actuating 
device 66 and attached locating pin 64 an adequate means for locating of 
the pawl 52. However, it is desirable to ensure that the pawl 52 will be 
maintained in engagement with the arcuate rack 50 during use of the 
vehicle seat until the occupant desires to change the relative angle of 
the arms of the hinge 10 to readjust the seat. Accordingly, the pawl 
actuating device is biased in a direction generally indicated by the arrow 
A to locate the pin 64 at the end 60 of the slot 58. With the pin 64 at 
the end 60 of the slot 58, the pawl 52 is radially positioned outwardly 
for full engagement with the arcuate rack 50. In the preferred embodiment 
of the invention the biasing of the pawl actuating device 66 is 
accomplished with a coil spring 74 having a first end 76 which is received 
within a slot 78 in the end 22 of the pivot pin 20. The spring 74 is 
retained on the end 22 with a C-clip 79 as shown in FIGS. 2 and 4. The 
second end 80 of the spring 74 acts on a tab 82 rigidly extending from the 
actuating device 66. Therefore, when the occupant desires to adjust the 
hinge 10, rotation of the actuating device 66 in a direction opposite that 
indicated by the arrow A in opposition to the biasing of the spring 74 
will rotationally reposition the pin 64 within the slots 70 and 72 and 
cause it to move toward the end 62 of the slot 58 of the pawl 52. When the 
pin 64 is at the end 62 of the slot 58, which is more remote than the end 
60 from the axis 16 throughout radial movement of the pawl 52, the pawl 52 
will be moved radially in a direction indicated by the arrow B out of 
engagement with the arcuate rack 50. When the pawl 52 is disengaged from 
the rack 50, the seat can be adjusted to alter the angle of the hinge arm 
14 with respect to the arm 12 until a desired angle is obtained. Allowing 
the actuating device 66 to return to its biased position will cause the 
locating pin 64 to again act on the slot 58 to return the pawl 52 into 
engagement with the rack 50 to maintain the desired angle between the 
hinge arms 12 and 14. 
In the preferred adjustable hinge 10, two means are provided for rotation 
of the actuating device 66 against biasing. As seen in FIG. 4, a handle 84 
is secured to the actuating device 66 at a threaded fitting 86. The 
fitting 86 is displaced from the center of the actuating device 66 because 
of the nonrotating pivot pin extending therethrough, but is adapted to 
receive the handle 84 which is generally aligned with the axis 16 to 
overlie the pivot pin 20 so that rotation of the handle is, nevertheless, 
about the axis 16. Additionally, a T-fitting 88 is provided on the 
actuating device 66 at a location which is remote from the axis 16 to 
receive the end of a cable 90 which allows remote control of the actuating 
device 66. As seen in FIG. 2, a remote lever device (not shown) can be 
rotated to pull the cable 90 in a direction as generally shown by the 
arrow C to rotate the actuating device against the biasing of the spring 
74 in a manner similar to that produced by the handle 84. When the 
preferred hinge 10 is installed on a seat, the T-fitting 88 and cable 90 
will be in an unexposed location behind the seat trim so that it will not 
interfere with the operation of the actuating device 66 by the handle 84 
which will be located outwardly of the seat trim. 
While the preferred hinge 10 as described above includes means for 
selectively releasing and maintaining the arms 12 and 14 at a desired 
angle, there are additional features desirable when utilized in an 
automotive seat configuration. As primarily seen in FIGS. 4 and 5, the 
preferred hinge is provided a counterbalanced spring 92 which is designed 
to provide biasing of the back frame relative to the cushion frame in a 
forward direction when the back frame is generally located between an 
upright position and an extreme rearward position. The spring 92 thus 
enables the occupant to more readily select the slope of the back frame as 
he operates the actuating device 66. The spring 92 is adapted to bias the 
second arm 14 by having the first end 94 thereof received within a slot 96 
of the end 48 of the pin 20 as the other end 98 acts on a fixed pin 100 of 
the second arm 14. Since the pin 20, as discussed hereinabove, is rigidly 
secured to the first arm 12, the spring 92 as thus mounted produces the 
desired biasing between the back frame and the cushion frame in a 
direction as generally indicated by the arrow D. The spring 92 is located 
about the end 48 of the pin 20 to lie adjacent the retention plate 44 and 
is retained thereon by a C-clip 102. To prevent the spring 92 from 
applying a biasing force to the back frame at locations thereof from the 
generally upright position to an extreme forward position, an extension 
104 on the retention plate 44 is provided to make contact with the spring 
92 when the back frame is at the upright location. Accordingly, the back 
frame may be positioned forwardly, in a counterclockwise direction from 
the location shown in FIG. 5 without the back frame being biased by the 
spring 92. This enables one to release and relocate the back frame for 
allowing an occupant to enter the back seat of the vehicle without having 
the biasing of spring 92 interfere with the user. A light cover 106 is 
installed over the spring 92 prior to installation of the hinge 10 on the 
back frames to prevent the cushion stuffing, etc. from interfering with 
the operation of the spring. 
To generally maintain the arm 12 and the arm 14 within predetermined 
angular limits with respect to each other, a pair of stop devices are 
provided. In the preferred embodiment, an extension 108 on the first arm 
12 is provided to make contact with an extended fitting 110 on the second 
arm 14 when the back frame is at an extreme rear position. A similar 
extended fitting 112 on the second arm 14 and extended fitting 114 on the 
first arm 12 similarly prevent forward movement of the back frame beyond 
an extreme forward position. 
While particular embodiments of the present invention have been illustrated 
and described herein, it is, of course, to be understood that changes and 
modifications may be made herein within the scope of the following claims.