Abstract:
An armchair mechanism that includes a toothed pawl and cam mechanism which allows the armrest to rotate in an arc greater than 90 degrees and into a first angular position. The armchair mechanism further includes a lockout member which locks the armrest in a design position and a stowed position. During a first angular portion of movement along the rotation arc, the armrest can be secured in several discrete angular positions whereas movement of the armrest in the first angular position is one-way so that the armrest can only rotate upward and be secured in any one of the several discrete angular positions.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to an adjustment mechanism and an armrest for using the adjustment mechanism, and more particularly, to an armrest adjustment mechanism and armrest for use within a vehicle. 
       BACKGROUND OF THE INVENTION 
       [0002]    Vehicle seats, especially those located in the rear of vans or mini-vans, often have an armrest pivotable from a generally vertical, stowed position to a generally horizontal, in-use design position. When in the stowed position, the armrest does not hinder movement into or out of the seat and facilitates folding the backrest of the seat to allow the seat to be more easily removed from the vehicle or stored within the vehicle. 
         [0003]    In some applications, it is desirable for the armrest to be adjustable to one of many fixed positions between the design position and the fully upright stowed position. A mechanism for implementing such a function in an armrest is shown in U.S. Pat. No. 6,106,068, issued to Marc Lefevere. 
         [0004]    The armrest mechanism shown in that patent uses two ratchets. When in contact, the ratchets can be rotated in only one direction. After the two ratchets are rotated a predetermined amount, one of the two ratchets is then retained in a locking mechanism separate from the other ratchet, thereby allowing the armrest to be rotated in the opposite direction. When the ratchets have been rotated relative to each other a predetermined amount, the latch is released, and the two ratchets are once again placed in contact. 
         [0005]    One problem with such a mechanism is that the latch may become worn, allowing premature contact between the two ratchets. Additionally, the latch may not reliably release the ratchet, requiring an additional force to move the armrest into the desired position. 
         [0006]    An improved armrest mechanism allowing for adjustment of an armrest into multiple positions between the design position and the stowed position is highly desirable. 
       SUMMARY OF THE INVENTION 
       [0007]    The improved armrest mechanism utilizing this invention allows an armrest to travel in an arc of somewhat more than ninety degrees. During a first angular portion of the arc, the armrest can be secured in several discrete angular positions. Movement of the armrest in the first portion is “one way” (e.g., counterclockwise)—it can be rotated only upward but also allowing it to be secured at one of several discrete positions. If the armrest is rotated beyond the first angular portion by several degrees, then the armrest can either be rotated further to the stowed position or it can be returned to the design position. If secured in the stowed position, the armrest can be rotated further in the same counterclockwise direction, and the armrest is then released so as to be rotated clockwise for return to the design position. Once the armrest is released from the stowed position, the armrest cannot be returned to the stowed position unless the armrest has been moved several degrees toward the design position. 
         [0008]    To accomplish this movement, the armrest mechanism utilizes a combination of a toothed pawl with a cam. A lockout member is provided with a design position portion and a stowed position portion. Both portions are toothed. When rotated, 
         [0009]      FIG. 7  shows the armrest mechanism in the design position. 
         [0010]      FIGS. 8-10  show the armrest mechanism as it rotates counterclockwise from the design position to the stowed position. 
         [0011]      FIG. 11A-12  shows the armrest mechanism entering the stowed position. 
         [0012]      FIGS. 13A-14B  show the armrest mechanism being moved from the stowed position counterclockwise prior to movement in the clockwise. 
         [0013]      FIGS. 15A-18  show the armrest mechanism  18  rotated in the clockwise direction to the design position. 
     
    
     DESCRIPTION OF THE INVENTION 
       [0014]    For the purposes of this description, the armrest moves counterclockwise from the design position to the stowed position. Obviously, the armrest could rotate clockwise from the design position to the stowed position 
         [0015]      FIG. 1A  shows armrest  2  attached to a seat  4  when the armrest is in the design position. Arc  6  shows the range of movement of armrest  2 . Arc  6  is divided into angular portion I, angular portion II, and angular portion III. The armrest may be rotated counterclockwise to the stowed position, shown in  FIG. 1B . 
         [0016]    In angular portion I, user can position the armrest at discrete angles between the design position and the stowed position. The armrest resists any movement in the clockwise direction, although the armrest can be rotated in the counterclockwise direction. When the armrest is moved into angular portion II, the armrest can be moved either to the stowed position or the design position. If the armrest is moved to the stowed position, armrest  2  is rotated to the end of angular portion III in order to release armrest  2  from the stowed position. After the armrest is released, the armrest can be moved to angular portion II and then returned to the design position. When rotating in the clockwise direction, the armrest will not lock into any position other than the design position. 
         [0017]      FIG. 2  is a perspective view of the armrest assembly  14 . Armrest assembly  14  has bolt  16  for insertion into the seat. Armrest mechanism  18  is contained within armrest housing  20 . 
         [0018]      FIG. 3  is a side view of the armrest assembly  14 .  FIG. 4  is an exploded view of armrest assembly  14 .  FIG. 5  is a view of the armrest assembly  14 , and more specifically armrest mechanism  18 , taken along section B-B of  FIG. 3 . 
         [0019]    The explanation of the components of armrest assembly  14  is with reference to  FIGS. 4 and 5  conjointly. 
         [0020]    Bolts  50  are used to retain right cover  52  to left cover  54 . Plate cover sides  56 ,  58  are used to armrest mechanism  18 . Cylinder pin  17  attaches bolt  16  to lockout mechanism  68 . Damper  64  is placed around bolt  16 . Damper springs  60 ,  62  provide some resistance to the motion of the armrest in either the clockwise or counterclockwise direction. Spring blade  66  is returns the main sector bypass  72  to its first position as shown in  FIG. 7 . 
         [0021]    Lockout member  68  is a generally cylindrical arrangement enabling the various feature of the armrest assembly. Stowed bypass  70  and main bypass  72  interact with lockout member  68  to enable the functionality of the bypass mechanism. Pawl  74  is attached to plate cover sides  56 ,  58  by way of pawl axle  76 . Pawl axle  76  rests within pawl axle holes  78 ,  80 . Pawl spring  82  urges pawl  74  into contact with lockout member  68 . Pawl  74  includes pawl pin  75  and pawl teeth  100 . 
         [0022]      FIG. 6  shows lockout member  68  in more detail. Lockout guide  80  is circular, with portions cut from the perimeter to form lockout guide portion  90 . As pawl pin  75  travels within lockout guide portion  90 , pawl  74  is rotated on pawl axle  76 , thereby causing pawl teeth  100  to engage or disengage from lockout teeth  92 . 
         [0023]    The operation of armrest mechanism  18  will be shown with reference to  FIGS. 7-18 .  FIG. 7  shows the armrest mechanism  18  in the design position. Spring  82  urges pawl teeth  100  of pawl  74  against first teeth portion  102  of lockout member  68 . Pawl pin  75  rests between main bypass guide portion  104  of main bypass  72  and wall  106  of lockout member  68 . Main bypass  72  is attached to lockout member  68  by way of pin  108 . Thus, main bypass  72  can rock from a first position to a second position. Similarly, stowed bypass  70  is attached to lockout member  68  by way of pin  110 . Stowed bypass  70  can also rock from a first position to a second position. 
         [0024]      FIG. 8  shows armrest mechanism  18  rotating counterclockwise from the design position. Spring  82  continues to urge pawl teeth  100  against first teeth portion  102 . Pawl pin  75  goes under main bypass stop  104 , thereby lifting main bypass  72 . Main bypass  72  pivots about pin  108 , and flexes spring blade  66 . The interaction of pawl pin  75  with main bypass  72  causes first teeth portion  102  and pawl teeth  100  to remain firmly engaged while providing a user with tactile feedback. 
         [0025]    First teeth portion  102 , and pawl teeth  100  prevent rotation of armrest mechanism  18  in the clockwise direction. 
         [0026]      FIG. 9  shows pawl pin  75  encountering slope  110  of lockout guide portion  90  while the armrest is rotating in the counterclockwise direction. Slope  110  lifts pawl teeth  100  away from first teeth portion  102 . 
         [0027]      FIG. 10  shows pawl pin  75  after being lifted away from first teeth portion  102  by lockout guide portion  90 . Armrest mechanism  18  can be rotated either in the clockwise or counterclockwise direction. 
         [0028]      FIG. 11A  shows pawl pin  75  entering under the first detail  117  of stowed bypass  70 , moving stowed bypass  70 .  FIG. 11B  shows pawl pin  75  entering the first trough  120 . 
         [0029]      FIG. 12  shows pawl pin  75  under stop  122 . Pawl teeth  100  are fully engaged with second teeth portion  120 . In this position, armrest mechanism  18  can be rotated only in the counterclockwise direction. Armrest mechanism  18  is in the stowed position. 
         [0030]    In  FIG. 13A , armrest mechanism  18  has been rotated further in the counterclockwise direction. Pawl pin  75  pushes the ramp portion  134  of the third detail thereby pushing stowed bypass  70  down.  FIG. 13B  shows stowed bypass  70  in the bypass position. 
         [0031]      FIG. 14A  shows pawl pin  75  lifted by ramp portion  134 . Stowed bypass  70 , like main bypass  72  rotates about pin  130 . This results in pawl pin using a different path on the up/lock stroke than on the down/release stroke. When pawl pin  75  pushed on the third detail of the stowed bypass  70 , the force creates an indication to the user that the armrest can now be rotated in the clockwise direction. 
         [0032]      FIG. 14B  shows pawl pin  75  on the top of first detail  122 . At this time, movement of the armrest can occur in the clockwise direction. 
         [0033]      FIGS. 15A and 15B  show the armrest mechanism  18  as the armrest is rotated in the clockwise direction. Pawl pin  75  moves over the top of the first detail  122  toward plateau  160 . Therefore, the teeth do not engage and allow the armrest to be moved away from the stowed position. 
         [0034]    In  FIG. 16 , pawl pin  75  is traveling on plateau  160  of lockout guide portion  90 . Pawl teeth  100  are thus kept away from lockout member  68 . 
         [0035]      FIG. 17  shows the pawl pin  75  going over stop  104 . In  FIG. 18 , pawl pin  75  has reached the end of stop  104 . Spring  82  urges pawl pin  75  between stop  104  and wall  106 . 
         [0036]    At this position, the armrest mechanism is near its original starting position shown in  FIG. 7 . 
         [0037]    The above description is of the preferred embodiment. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any references to claim elements in the singular, for example, using the articles “a,” “the,” or “said,” is not to be construed as limiting the element to the singular.