Abstract:
A vehicle seat assembly comprising a seat cushion and a seat back mounted to the seat cushion. An armrest is pivotally mounted to the seat back in a manner which will allows the armrest to rotate relative to the seat back. The seat assembly includes a cam for guiding the armrest in a lateral direction as the armrest is rotated about an axis between a non-use position and a use position. In particular, as the armrest is rotated downward to the use position, the cam forces the armrest to slide outwardly along the axis away from the seat back, and when the armrest is rotated upward to the non-use position the cam directs the armrest to slide inwardly along the axis toward the seat back.

Description:
BACKGROUND OF THE INVENTION 
     1) Field of the Invention 
     The subject invention relates to a vehicle seat having a retractable armrest. 
     2) Description of the Prior Art 
     Seats assemblies having pivoting armrests are commonly used in all types of seating applications. These types of seat assemblies typically include a shaft that is supported by a seat back. An armrest is mounted on an end of the shaft such that the armrest is allowed to rotate with or about the shaft. An example of this type of seat assembly is disclosed in U.S. Pat. No. 5,106,160. 
     Other prior art seat assemblies use mechanisms, that include multiple links and pivot points, which allow the armrest to pivot between a use position and a non-use position such as the seat assembly disclosed in U.S. Pat. No. 3,168,346. 
     Yet another prior art seat assembly involves mounting the armrest to a bracket having a slot to guide the armrest. The armrest includes a pin that extends into the slot. The armrest is pivotally mounted to the bracket such that the pin slides within the limits of the slot. An example of this seat assembly is disclosed in U.S. Pat. No. 5,292,171. 
     Other prior art seat assemblies include an armrest that is movably supported by a seat back such that the armrest moves laterally toward and away from the seat back when the armrest is pivoted between a non-use position and a use position. Seat assemblies of this type are disclosed in U.S. Pat. Nos. 3,168,346 and 4,159,145. These prior art seats employ either multiple hinges and slides to achieve the lateral movement, or a support structure that requires separate operating motions of first rotating the armrest and then laterally sliding the armrest. 
     Finally, seat assemblies have been developed which use a spring or some other means to bias an armrest either laterally toward or away from a seat back. These seats allow the armrest to move laterally as the armrest is rotated. Consequently, these type of seat assemblies require that the biasing means be manually overcome when the armrest is moved in the direction opposite the biasing force of the biasing means. 
     It would be desirable to develop a seat with an armrest assembly that automatically moves laterally with respect to the seat back as the armrest is pivoted between a use position and a non-use position. 
     SUMMARY OF THE INVENTION AND ADVANTAGES 
     A vehicle seat assembly according to this invention comprises a seat back and an armrest rotatably supported by the seat back in a manner that allows the armrest to rotate and move laterally relative to the seat back between a non-use and a use position. A cam, defining an axis, interconnects the armrest and the seat back. When moving between the non-use and use positions, the armrest rotates about the axis. As the armrest rotates about the axis, the cam guides the armrest axially along the axis. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
     FIG. 1 is a perspective view of a seat assembly according to the present invention; 
     FIG. 2 is a sectional view of the seat assembly taken along line  2 — 2  of FIG. 1; 
     FIG. 3 is a perspective view of a cam in accordance with the subject invention; 
     FIG. 4 is a side view of a frame for the armrest of the present invention; 
     FIG. 5 is a fragmentary and partially cut away perspective view of the cam and the armrest frame shown from the front and in the use position; 
     FIG. 6 is a fragmentary view of the cam and the armrest frame shown in a non-use position; 
     FIG. 7 is a perspective view of the cam and the armrest frame shown from the rear and in a use position; 
     FIG. 8 is a perspective view of the cam and a guide pin shown in the non-use position; and 
     FIG. 9 is a perspective view of the cam and the guide pin shown in the use position. 
    
    
     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 shown at  10  in FIGS. 1 and 2. The seat assembly  10  includes a seat cushion  12  and a seat back  14  mounted to the seat cushion  12 . As understood by those skilled in the art, the seat assembly  10  is preferably a bucket type seat wherein the seat cushion  12  and seat back  14  are of a suitable structure. As shown in FIG. 2, the seat back  14  includes a seat back frame  15  of a suitable type attached to the seat cushion  12  in a suitable manner. 
     An armrest  16  is rotatably and slidably supported by the seat back  14  for movement between non-use and use positions. It should be appreciated that the seat assembly  10  can include a single armrest  16 , or a pair of left and right armrests  16  (as shown). The shape of the armrest  16  can vary, however the armrest  16  preferably has a configuration that is complementary to the profile of the seat back  14  when the armrest  16  is in the non-use position. Specifically, the armrest  16  has an inner surface (not numbered) which is complementary in configuration with a corresponding outer side (not numbered) of the seat back  14 . 
     The left armrest  16 , with respect to FIGS. 1 &amp; 2 is shown in the non-use position. When the armrest  16  is in this non-use position, the armrest  16  is roughly vertical and extends upward along side the seat back  14 . The right armrest  16 , with respect to FIGS. 1 &amp; 2, is shown in the use position. When the armrest  16  is in this use position, the armrest  16  is roughly horizontal and extends forward from the seat back  14 . Each of the left and right armrests  16  are substantially mirror images of each other. Hence, for illustrative purposes, only one armrest  16  will be subsequently described. 
     The seat assembly  10  is characterized by a cam  18  that defines an axis  17 . The cam  18  interconnects the armrest  16  and the seat back frame  15 . When moving the armrest  16  between the non-use and use positions, the armrest  16  is rotated about the axis  17 . As the armrest  16  is rotated about the axis  17 , the cam guides the armrest axially along the axis. Preferably, as further described below, the cam  18  directs the armrest  16  to slide inwardly or laterally toward the seat back  14  along the axis  17  when the armrest  16  is rotated about the axis  17  from the use position to the non-use position. Conversely, when the armrest  16  is rotated about the axis  17  from the non-use position to the use position, the cam  18  directs the armrest  16  to slide outwardly or laterally away from the seat back  14  along the axis  17 . Alternatively, the cam  18  can be modified, as described below, to direct the armrest  16  in the opposite manner. A cam (not shown) modified consistent with this alternative embodiment directs the armrest  16  to slide outwardly or laterally away from the seat back  14  along the axis  17  as the armrest  16  is rotated from the use position to the non-use position. Conversely, when the armrest  16  is rotated from the non-use position to the use position, the cam of this alternative embodiment directs the armrest  16  to slide inwardly or laterally toward the seat back  14  along the axis  17 . 
     Referring to FIG. 3, the cam  18  includes a flange  19  attached to the seat back frame  15 . The flange  19  is attached to the seat back frame  15  by any suitable manner such as a welding, bolts, or the like. The cam  18  further includes a cylindrical tube  20  extending from the flange  19 . The tube  20  may be integrally formed with the flange  19 , or may be welded or otherwise suitably attached to the flange  19 . Preferably, the tube  20  is a hollow tube  20  having a pair of helical shaped channels or openings  22  formed on diametrically opposite sides of the tube  20 . Alternatively, the tube  20  can include a single channel  22 . If only a single channel  22  is employed, the tube  20  may be a solid tube (not shown) with the channel  22  being formed as a groove. 
     The tube  20  includes an outer end  26  and an inner end  28 . The helical shaped channels  22  each include a first end  30  and a second end  32 . The channels  22  are oriented such that the first ends  30  and the second ends  32  of the channels  22  are adjacent the outer end  26  and the inner end  28  of the tube  20 , respectively, with the channels  22  extending helically around the tube  20  between the first and second ends  30 ,  32 . 
     Referring to FIG. 4, the armrest includes an armrest frame  34  for supporting the armrest  16 . The armrest frame  34  includes an aperture  36  for receiving the tube  20 . The armrest frame  34  also includes a pair of circular bores  40  extending into the armrest frame  34 . In particular, there is one bore  40  formed within the frame  34  on one side of the aperture  36  with another bore  40  formed within the frame  34  on an opposing side of the aperture  36  with the bores  40  aligned to span the aperture  36 . 
     Referring to FIGS. 5, the armrest frame  34  is mounted to the cam  18 . A cam follower  38  is included to secure the frame  34  to the cam  18 . The cam follower  38  preferably comprises at least one guide pin  38  which is supported within the armrest frame  34  and disposed in the helical shaped channels  22 . Preferably, the guide pin  38  extends through both channels  22  in the tube  20  and is supported by each bore  40  of the armrest frame  34 . 
     During assembly of the armrest  16 , the armrest  16  is placed onto the tube  20  and the pin  38  is inserted through one of the circular bores  40 . The pin  38  extends through the channels  22  within the tube  20  and into the opposite circular bore  40 . Alternatively, if the tube  20  includes only one channel  22 , the pin  38  will be supported at one end, and extend into the tube  20  through the single channel  22  in a cantilevered fashion. 
     The armrest frame  34  is shown in the use and non-use positions in FIGS. 6 and 7, respectively. In moving from the non-use position to the use position, the armrest  16  is rotated downward. As the armrest is rotated, the guide pin  38  follows the helical shaped channels  22  to move the armrest  16  laterally away from the seat back  14 . Similarly, when the armrest  16  is rotated upward to the nonuse position, the guide pin  38  moves the armrest  16  laterally inward toward the seat back  14 . The helical pattern of the channel  22  or channels  22  directs the armrest  16  to move laterally along the tube  20  simultaneously as the armrest  16  is rotated about the tube  20 . 
     Referring to FIGS. 8 and 9, the armrest frame  34  is removed such that the movement of the pin  38  between the use and one-use positions within the cam  18  is best illustrated. When the armrest  16  is pivoted toward the non-use position, the guide pin  38  is directed along the channels  22  to the second ends  32  of the channels  22 , as shown in FIG.  8 . This movement directs the armrest  16  laterally along the tube  20  toward the seat back  14 . In the non-use position, the armrest  16  is in close proximity to the seat back  14 . When the armrest  16  is rotated downward to the use position the guide pin  38  is directed along the channels  22  until the guide pin  38  abuts the first ends  30  of the channels  22 , as shown in FIG.  9 . This movement directs the armrest  16  laterally along the tube  20  away from the seat back  14 . In the use position, the armrest  16  is positioned away from the seat back  14  so as to not interfere with the seating area for the passenger using the seat assembly  10 . 
     As discussed above, the cam  18  may be modified so that the armrest  16  moves toward the seat back  14  when the armrest  16  is rotated toward the use position and away from the seat back  14  when the armrest  16  is rotated toward the non-use position. In this alternative embodiment, the cam  18  is modified by reversing the orientation of the channels  22 . Specifically, the first and second ends  30  and  32  of the channels are adjacent the inner and outer ends  26  of the tube  20 , respectively. 
     Although not shown, the cam  18  and cam follower  38  of the seat assembly  10  could be altered such that a guide pin is supported by a tube and an armrest includes a helical shaped channel or channels. In this embodiment, the pin stays stationary along with the tube as the armrest is rotated along an axis of rotation. The armrest of this embodiment is directed inwardly or outwardly by the channels riding on the pin as the armrest is rotated about the tube. 
     A further embodiment (also not shown) includes a tube that is movable laterally within a seat back and an armrest that is mounted securely to the tube. In this embodiment, a guide pin is mounted to the tube, and a seat back frame includes a helical shaped channel or channels to direct the tube inward and outward as the armrest and tube are rotated. This embodiment may be altered where the tube includes a helical channel or channels and the seat back frame includes a stationary pin. 
     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. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that the invention may be practiced otherwise than as specifically described.