Patent Publication Number: US-6217119-B1

Title: Extendable armrest assembly for a seat

Description:
BACKGROUND OF THE INVENTION 
     In vehicles, such as trucks and automobiles, it has become common to provide an armrest beside or integral with a seat to provide a driver or passenger the opportunity to rest their arm thereon. Present seat manufacturers use fixed, or folding armrests on the side of seats. These armrests protrude into the space adjacent to the seat even when not in use, making actions such as ingress and egress difficult. Also, the space occupied by the armrest is unavailable for storage or other uses. 
     A need exists for improved seat assemblies with armrests which provide more efficient use of space and provide greater comfort and convenience for driver and passenger use. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, a seat assembly is provided. The seat assembly includes a seat portion and an armrest mounted to the seat portion for linear motion in a first direction and pivotal motion in a rotational plane generally perpendicular to the first direction. The armrest is moveable between a first position and a second position in the first direction. At least one of the first and second positions is a retracted position with the armrest retracted into the seat portion of the seat assembly. The other position is a deployed position, permitting the armrest to pivot in the rotational plane. 
     In accordance with another aspect of the present invention, a device is provided for urging the armrest in the first direction from the first position to the second position. The device can be a pneumatic cylinder, electric solenoid, or mechanical spring. The device can be used to urge the armrest from the retracted position along the first direction to the deployed position. 
     In accordance with another aspect of the present invention, the armrest can be provided with a shaft having a pin extending therefrom. The seat portion has a mount defining a cylindrical portion with a groove, the shaft received in the cylindrical portion with the pin in the groove. The groove is configured to have a linear portion along the first direction which transitions into a portion extending about the circumference of the cylindrical portion for movement of the armrest in the rotational plane. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taking in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a seat assembly forming a first embodiment of the present invention; 
     FIG. 2 is a detailed view of the first embodiment of FIG. 1 illustrating the pneumatic cylinder and armrest mount; 
     FIG. 3 is a perspective view of a seat assembly forming a second embodiment of the present invention; 
     FIG. 4 is a detailed view of the armrest mount and spring of the second embodiment of FIG. 3; 
     FIG. 5 is a back view of a seat assembly of the type known in the art; and 
     FIG. 6 is a back view of the seat assembly of the first embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference now to the accompanying drawings, and in particular to FIGS. 1,  2  and  6 , there is shown a left side seat assembly  10  forming a first embodiment of the present invention. The seat assembly includes a seat back  12 , a first, conventional armrest  14  on the outboard side of the seat back  12  and a retractable armrest  16  on the inboard side of the seat back  12 . 
     As can be readily understood, the seat back  12  can be mounted to other seat components, such as a generally horizontally extending seat portion which, in turn, can be mounted directly to a vehicle, or supported on a pedestal providing a shock absorber function, or permitting the seat to pivot about a vertical axis to aid in ingress and egress. Suitable upholstery and cushioning will be mounted on the seat back  12 , armrests  14  and  16  and other seat components as is well known in the industry. 
     The armrest  14  is pivotally mounted to the seat back  12  by an armrest mount  22  as conventionally known in the industry. However, retractable armrest  16  is mounted to be stored in a retracted position, as seen in FIG. 6, with the retractable armrest  16  retracted into a recess  20  in the side of seat back  12  when the armrest is not used. This maximizes the available space around the seat assembly. Once the driver or passenger is seated, the retractable armrest  16  can be moved out of the recess in the seat back  12  and deployed by the occupant for optimal comfort. 
     With specific reference to FIGS. 1 and 2, the first embodiment will be described in detailed. The seat back  12  mounts conventional armrest mount  22  on the outboard side and the retractable armrest mount  18  on the inboard side. The conventional armrest  14  has a rod (not shown) which extends into and is rotatably mounted within the conventional armrest mount  22 , which allows the armrest  14  to pivot about axis  24  in a conventional known manner to allow the occupant of the seat to move the armrest down to the horizontal position shown in FIG. 1 for use or pivot it back to the vertical position parallel with the seat back  12 . 
     The retractable armrest  16  has a rod  26  which extends through a cylindrical opening through the mount  18  and ends in a spline  28 . The length of the rod  26  exceeds the length of the mount  18  so that the rod can move along the axis  24  to move the armrest  16  between the retracted position in the recess  20  of the seat to the deployed position where it can be pivoted down for use. 
     Extending from the rod  26  is a guide pin  30  which is received in a guide slot  32  formed in the mount  18 . As can be seen in the Figures, the guide slot  32  has a linear portion  34  which extends along the axis  24  and transitions into a circumferential portion  36  which extends for an arc of about 90 degrees or so in a plane perpendicular to the axis  24 . 
     A pneumatic cylinder  38  is mounted on the seat back  12  with the base of the pneumatic cylinder securely mounted to a bracket  40  on the seat back  12 . The piston rod  42  of the pneumatic cylinder extends to a clevis  44  which extends over the spline  28 . A pin  46  passes through aligned holes in the clevis  44  and spline  28  to secure the piston rod to the rod  26 . 
     The pneumatic cylinder  38  is preferably a single acting cylinder which, when a gas under pressure is provided to the cylinder, extends the piston rod  42  in the direction of the mount  18 . This causes the armrest  16  to move from the retracted position to the deployed position. Once the armrest  16  is in the deployed position, the occupant of the seat can manipulate the armrest  16  as desired by pivoting the armrest about axis  24 . The guide pin and guide slot  32  ensure that the armrest  16  will remain in the vertical orientation until it is clear of the seat back. The piston rod  42  can rotate about the axis  24  with rod  26 . Alternatively, a rotary coupling could be installed between rod  26  and piston  42 . 
     Preferably, the pneumatic cylinder  38  has an internal spring which urges the piston rod  42  to the retracted position within the cylinder. Alternatively, a spring external the pneumatic cylinder can serve the same function. When the armrest  16  is to be returned to the retracted position, the armrest  16  need only be moved to the vertical position, whereupon the spring within the pneumatic cylinder will draw the armrest  16  into the retracted position within the recess  20 . 
     The gas pressure in the pneumatic cylinder  38  deploying the armrest could be removed immediately after the occupant of the seat pivots the armrest down into the normal use position. In that position, the spring within the pneumatic cylinder could not retract the armrest because the pin  30  would contact the side of guide slot  32  in the circumferential portion  36  to prevent movement of the armrest  16  along axis  24 . When the occupant wished to retract the armrest, all that would be necessary would be to pivot the armrest up to the vertical position, allowing the pin  30  to enter the linear portion  34  of the guide slot  32 . The spring within the pneumatic cylinder would then draw the armrest  16  into the retracted position. Alternatively, gas pressure can be maintained within the pneumatic cylinder  38  until the armrest  16  is actually to be retracted. This would permit the occupant of the seat to move the armrest  16  between the vertical position and the horizontal position as often as desired without the armrest  16  actually be retracted into the recess  20 . 
     While the pneumatic cylinder  38  has been described as a single acting cylinder to deploy the armrest  16 , the pneumatic cylinder can alternatively be a single acting cylinder to retract the armrest  16  within the recess  20 . In such a situation, a spring could be mounted in the pneumatic cylinder or external to the pneumatic cylinder to urge the armrest  16  to the extended position in the absence of gas pressure within the pneumatic cylinder  38 . Alternatively, the pneumatic cylinder  38  can be a double acting cylinder, allowing pressure to be inserted on one side of the piston within the cylinder to deploy the armrest and on the other side of the piston to retract the armrest. Gas under pressure can be supplied from an engine driven compressor, or other source, and controlled by suitable controls conveniently located for the seat occupant. Further, the pneumatic cylinder  38  could be replaced by any other type of actuator, such as a electrical solenoid actuator, motor driven ball screw actuator or other suitable mechanism. 
     With reference to FIGS. 3 and 4, a seat assembly  100  forming a second embodiment of the present invention will be described. Numerous components in seat assembly  100  are identical to those in seat assembly  10  and are identified by the same reference numerals. Retractable armrest  16  is provided with a modified rod  102  which is received in a modified armrest mount  104 . Rod  102  mounts guide pin  30  and mount  104  has a guide slot  32  with the linear portion  34  and circumferential portion  36 . 
     A coil spring  106  is circumferentially fit about the portion of the rod  102  between the outer end  108  of the mount  104  and the armrest  16  itself The spring  106  acts to urge the rod  102  along the axis  24  in a direction to deploy the armrest  16 . A spring loaded ball  110  is mounted at the inner end of the rod  102  which extends to engage the inner end  112  of the mount  104  when the armrest  16  is in the retracted position. The force of the spring loaded ball  110  acting on the inner end  112  is sufficient to overcome the force of the spring  106  so that the armrest  16  is held in the retracted position. The occupant of the seat will manually be required to draw the armrest  16  out of the recess  20  into the deployed position by overcoming the force of the spring loaded ball  110 . Once the resistance of the spring loaded ball  110  is overcome, the spring  106  assists the occupant in moving the armrest  16  to the deployed position. The armrest  16  can then be pivoted about the axis  24 , with the guide pin  30  running in the circumferential portion  36  of the guide  32 , to move the armrest  16  to a horizontal position or other comfortable position for use. 
     To retract the armrest  16  in the seat assembly  100 , the occupant would simply need to rotate the armrest  16  about axis  24  to the vertical position and then manually push the armrest  16  into the recess, overcoming the force of spring  106 , until the spring loaded ball  110  pops out into engagement with the inner end  112  of the mount  104  to secure the armrest  16  in the retracted position. 
     The transition between the guide slot linear portion  34  and circumferential portion  36  can be tailored to the desired behavior of the seat assembly. If the transition between linear portion  34  and circumferential portion  36  is relatively abrupt, the air cylinder, spring or other actuator will essentially simply cause the armrest  16  to move from the retracted position to the deployed position but cause the armrest  16  to remain in the vertical orientation. The armrest  16  must be manually moved to the horizontal position by the occupant. If a more curved transition is formed between the linear portion  34  and the circumferential portion  36 , the force of movement of the armrest  16  from the retracted position to the deployed position can cause the armrest to be automatically forced forward and down into the horizontal position for use. 
     With reference to FIGS. 5 and 6, the savings of width in the seat assembly is well illustrated. In FIG.  5  and FIG. 6, the seat backs  150  and  12  have substantially the identical width. A conventional armrest  14  is mounted on the outboard side of each seat back  150  and  12  and can be seen to occupy a significant portion of the entire width of the seat assembly. A conventional armrest  14  is also illustrated on the inboard side of the conventional seat assembly  150  in FIG.  5 . In contrast, the improved seat assembly  10  of FIG. 6 illustrates a retractable armrest  16  on the inboard side of the seat assembly  10  which is in the retracted position, reducing the width occupied by the seat assembly. This maximizes the available space around the seat assembly by providing for retraction of the armrest into the seat back when not in use. 
     Although several embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions of parts and elements without departing from the spirit and scope of the invention.