Armrest cover positioning mechanism

An armrest assembly comprising a bin defining a storage compartment and a cover hinged to the bin for movement between open and closed positions. A shaft rotatably supports the cover on the bin for pivotal movement of the cover relative to the bin. A helical torsion spring is coiled about the shaft and has one end reacting with the bin and the other end reacting with the cover for continuously urging the cover to the open position. A detent, having at least one caming surface, is disposed on the shaft for engaging the bin and is rotatable with the cover for retaining the cover in at least one detent position. The detent is located between the bin and the spring. Accordingly, the spring continuously biases the detent axially against the bin and also continuously biases the cover to the open position.

TECHNICAL FIELD 
The subject invention relates generally to a vehicle armrest assembly, and 
more specifically, to an armrest assembly having a spring biased cover and 
a coacting detent which maintains the cover in a desired position. 
BACKGROUND OF THE INVENTION 
Vehicles having an armrest assembly mounted to a seat assembly to provide a 
comfortable forearm rest for a driver and/or a passenger are well known in 
the art. These armrest assemblies typically pivot between a horizontal use 
position and a vertical storage position. Often, the armrest assembly 
comprises a bin defining a storage compartment and a cover hinged to the 
bin for covering the bin in a closed position and opening the storage 
compartment in an open position. The cover is hinged to the bin by a 
rotatable shaft mounted within or above the bin. Cupholders, writing pads, 
and portable phone mounts may be mounted within the storage compartment 
for use when the cover is opened. The storage compartment is also used for 
storing articles such as cassette tapes, compact discs, coins, and the 
like. 
A latch is typically provided between the cover and the bin to maintain the 
cover in a latched position when the armrest is pivoted to the vertical 
storage position. This latch ensures that cover will not open and that the 
contents in the storage compartment will not fall out when the armrest is 
pivoted upwardly. 
In certain armrest applications it is desirable to have a torsion spring 
coiled about the shaft for biasing the cover into the open position. The 
spring assists a user in opening the cover to the armrest and also assists 
in maintaining the cover in the open position. As can be appreciated it is 
important to maintain the cover in the open position when utilizing a 
device that is located within the bin, i.e., a writing pad, cupholder, 
portable phone mount or the like. These prior art spring biased covers, 
however, do not provide a detent with a positive locking position for the 
cover which maintains the cover in a desired position throughout sudden 
decelerations and similar driving conditions. 
SUMMARY OF THE INVENTION AND ADVANTAGES 
The subject invention relates to a vehicle seat armrest assembly comprising 
a bin and a cover for covering the bin. A shaft rotatably supports the 
cover on the bin for pivotal movement of the cover relative to the bin 
between a closed position and an open position. A torsion spring is coiled 
about the shaft with a first end reacting with the bin and a second end 
reacting with the cover for urging the cover to the open position in 
response to winding of the spring. A detent is disposed on the shaft for 
engaging the bin and is rotatable with the cover for retaining the cover 
in at least one detent position whereby the spring biases the detent 
axially against the bin. 
Accordingly, this armrest assembly provides a compact concealable detent 
mechanism located on a rotatable shaft which maintains an armrest cover in 
a desired position by a spring which continuously biases an armrest cover 
upwardly and also continuously biases the detent toward an armrest bin for 
continuous engagement of the detent with the bin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the Figures, wherein like numerals indicate like or 
corresponding parts throughout the several views, a vehicle seat assembly 
is generally indicated at 10 in FIG. 1. The seat assembly 10 includes a 
generally horizontal seat bottom portion 12 and a generally vertical seat 
back portion 14. An armrest assembly 16 is pivotally mounted within the 
seat back portion 14 and pivotal between a generally horizontal use 
position parallel with the seat bottom portion 12 and a vertical storage 
position generally parallel to the seat back portion 14. The armrest 
assembly 16 is mounted to the seat back portion 14 by a bracket assembly 
(not shown) which provides rotation of the armrest assembly 16 between the 
horizontal use position and the vertical storage position. 
The armrest assembly 16 is molded of plastic material and may be covered 
with a padded foam, plastic, or trim as commonly known in the art. The 
armrest assembly 16 comprises a bin 18 defining a storage compartment 20 
and a cover 22 hinged to the bin 18 for covering the bin 18 in a closed 
position and opening the storage compartment 20 in an open position (as 
shown). More specifically, the bin 18 comprises a front wall 24, side 
walls 26, a back wall 28, and a bottom (not shown) which further define 
the shape of the storage compartment 20. Interior spaces or cavities (not 
shown) may be located within the storage compartment 20 for retaining any 
number of articles (not shown), i.e., cassette tapes, compact discs, coins 
and the like. Further, cupholders, writing pads, and portable phone mounts 
(not shown) may be provided within the storage compartment 20 for 
selective use by a user within or outside the bin 18. 
Referring also to FIG. 2, a shaft 30 rotatably supports the cover 22 on the 
bin 18 for pivotal movement of the cover 22 relative to the bin 18 between 
the closed position and the open position. Specifically, the shaft 30 is 
supported by a pair of brackets 32, 34 that rise upwardly from the 
backwall 28 of the bin 18. The pair of brackets 32, 34 comprises a spring 
bracket 32 and a detent bracket 34. The shaft 30 extends through the 
brackets 32, 34, whereby the distal ends of the shaft 30 extend outwardly 
from the brackets 32, 34. A flat metal plate 36 is mounted to an inside 
surface of the cover 22 and pivotally engages the distal ends of the shaft 
30. Hence, the cover 22 pivots freely along the shaft 30 and the shaft 30 
pivots within the spring 32 and detent 34 brackets. 
A helical torsion spring 38 is coiled about the shaft 30 between the spring 
32 and detent 34 brackets, whereby the spring 38 is in constant engagement 
with the brackets 32, 34. Hence, regardless of the cover's 22 position the 
spring 38 is continuously biasing outwardly against the spring 32 and 
detent 34 brackets. A first end 40 of the spring 38 reacts with the bin 18 
and a second end 42 of the spring 38 reacts with the cover 22 for urging 
the cover 22 to the open position in response to winding of the spring 38. 
Both the first 40 and second 42 ends of the spring 38 have an arm 44 
extending radially therefrom. Accordingly, the arm 44 of the first end 40 
of the spring 38 rests against the spring bracket 32 extending from the 
bin 18. As best shown in FIG. 5, a first abutment 51 is disposed within 
the interior face of the spring bracket 32. The abutment 51 comprises a 
circular exterior wall 53 which surrounds a sloping inner surface 54, 
whereby the sloping inner surface 54 extends helically downward into a 
groove 56. The spring 38 is disposed within the sloping inner surface 54 
and the arm 44 of the first end 40 engages the groove 56 of the first 
abutment 51. 
The arm 44 of the second end 42 of the spring 38 rests against the inside 
surface of the metal plate 36. Hence, the spring 38 also continuously 
biases the cover 22 to the open position. Specifically, when the cover 22 
is closed and latched to the bin 18 the spring 38 is wound a half turn 
tighter around the shaft 30. The spring 38 unwinds a quarter turn when the 
cover 22 is completely opened. The spring 38 is wound tighter around the 
shaft 30 because the residual stresses on the spring 38 are reduced if the 
spring 38 is wound in the same direction as the spring 38 is coiled. As is 
readily apparent, the spring 38 continuously acts in two directions, 
axially toward the spring 32 and detent 34 brackets, and rotatably against 
the spring bracket 32 and the metal plate 36. 
A detent 46 is disposed on the shaft 30 for engaging the detent bracket 34 
on the bin 18. The detent 46, which includes an interior face 48 and an 
exterior face 50, is rotatable with the cover 22 for retaining the cover 
22 in at least one detent position. A second abutment 52 is disposed 
within the interior face 48 of the detent 46 for mechanical interlocking 
engagement with the arm 44 of the second end 42 of the spring 38. 
Generally, the abutment 52 extends radially from the shaft 30 which 
provides for easy engagement of the radially extending arm 44 of the 
spring 38. As best shown in FIG. 4, the second abutment 52 also comprises 
the sloping inner surface 54 extending helically downward into the groove 
56. The spring 38 is disposed within the sloping inner surface 54 and the 
arm 44 of the second end 42 engages the groove 56 of the second abutment 
52. Hence, the spring 38, detent 46, metal plate 36, and cover 22 all 
rotate from the closed position to the open position as a single unit. As 
discussed above, the spring 38 continuously biases the detent 46 axially 
against the detent bracket 34 thereby maintaining the detent 46 in 
constant engagement with the detent bracket 34. 
The armrest assembly 16 also includes coacting undulations 58 located 
between the detent 46 and the detent bracket 34 of the bin 18 for 
affecting axial movement of the detent 46 against the biasing action of 
the spring 38. Each of the coacting undulations 58 on the detent 46 
includes a caming surface 60 which translates rotary motion of the detent 
46 into the axial movement of the detent 46 and the spring 38. The detent 
46 includes a first plurality of caming surfaces 60 and the detent bracket 
34 includes a second plurality of caming surfaces 60 for coacting 
engagement with the first plurality of the caming surfaces 60 of the 
detent 46. As best shown in FIG. 3, each of the caming surfaces 60 
includes a first ramp 62 extending upwardly from a base 64 to a crest 66. 
A plurality of these caming surfaces 60 extend circumferentially along the 
exterior face 50 of the detent 46 and along the corresponding face of the 
detent bracket 34. Each of the caming surfaces 60 also includes a second 
ramp 68 extending downwardly from the crest 66 of the first ramp 62. The 
second ramps 68 abut each of the bases 64 of the first ramps 62 wherein 
each second ramp 68 and each base 64 of the first ramps 62 define the 
detent position. In general, the coacting undulations 58 include at least 
one detent position wherein the cover 22 pivots upwardly relative to the 
bin 18. 
FIGS. 6, 7, and 8 illustrate the operation of the cover 22 from a closed 
position covering the bin 18 to an open position raised above the bin 18. 
In FIG. 6 the cover 22 is closed and latched to the bin 18. The spring 38 
biases the detent 46 toward the detent bracket 34 which engages the caming 
surfaces 60 of the detent 46 with the caming surfaces 60 of the detent 
bracket 34. Specifically, the crests 66 of the caming surfaces 60 of the 
detent 46 are partially spaced from the bases 64 of the caming surfaces 60 
of the detent bracket 34 and similarly the crests 66 of the caming 
surfaces 60 of the detent bracket 34 are partially spaced from the bases 
64 of the caming surfaces 60 of the detent 46. In other words, the crests 
66 of the caming surfaces 60 of the detent 46 are engaging the first ramps 
62 of the detent bracket 34 and similarly the crests 66 of the caming 
surfaces 60 of the detent bracket 34 are engaging the first ramps 62 of 
the detent 46. As the cover 22 opens, the crests 66 move circumferentially 
along the first ramps 62 and the detent 46 is pushed axially away from the 
detent bracket 34 which in turn compresses the spring 38. This movement of 
the detent 46 and the compression of the spring 38 continues until the 
crests 66 of the detent 46 meet the crests 66 of the detent bracket 34 (as 
shown in FIG. 7). The spring 38 then quickly pushes the detent 46 toward 
the detent bracket 34 whereby the crests 66 of both the detent 46 and the 
detent bracket 34 slide down their corresponding second ramp 68 to a 
corresponding base 64. As shown in FIG. 8, the detent 46 positively locks 
the cover 22 into the fully open position whereby the crests 66 of the 
caming surfaces 60 of the detent 46 engage the bases 64 of the caming 
surfaces 60 of the detent bracket 34 and similarly the crests 66 of the 
caming surfaces 60 of the detent bracket 34 engage the bases 64 of the 
caming surfaces 60 of the detent 46. 
To close the cover 22, a user simply pushes the cover 22 downwardly toward 
the bin 18 with sufficient force to overcome the biasing force of the 
spring 38 and the frictional forces between the caming surfaces 60 of the 
detent 46 and the caming surfaces 60 of the detent bracket 34. As is 
apparent to one skilled in the art, the detent 46 and detent bracket 34 
may have numerous caming surfaces 60 to provide any number of positive 
stops for the cover 22. Further, the caming surfaces 60 of the detent 46 
and the detent bracket 34 may be of different configurations without 
deviating from the scope of the subject invention. 
The invention has been described in an illustrative manner, and it is to be 
understood that the terminology which has been used is intended to be in 
the nature of words of description rather than of limitation. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is, therefore, to be 
understood that within the scope of the appended claims, wherein reference 
numerals are merely for convenience and are not to be in any way limiting, 
the invention may be practiced otherwise than as specifically described.