Abstract:
A vertically adjustable armrest that is suitable for use in connection with various types of passenger vehicles, including commercial aircraft. The armrest includes a slide mechanism for permitting easy height adjustment of the armrest and also includes a locking mechanism for securely locking the headrest in the desired elevated position. The armrest moves in a smooth vertical motion and is continuously biased toward an upraised position. Vertical adjustment of the armrest is accomplished by pushing a push button located in the upper portion of the armrest.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to armrests for seats. More particularly, the invention concerns a vertically adjustable armrest for use in connection with furniture and with passenger vehicles such as aircraft, trains and busses. 
   2. Discussion of the Prior Art 
   Various types of seat armrests for use in passenger vehicles have been suggested in the past. As a general rule, these armrests are fixedly mounted to either the seat or back portion of the seat. In those instances where the armrests are adjustable, the armrest is typically pivotally mounted to the seat back in a manner to enable the armrest to be pivoted along an arcuate path from a downward operational position into a retracted, stowed position. 
   On occasion, attempts have been made to develop self-leveling chair arms for use in theaters and the like. An example of one such attempt is disclosed in U.S. Pat. No. 4,400,033 issued to Pietsch. This patent concerns a theatre, or stadium chair having a seat, a seat back and an arm connected to the seat back by means of a parallelogram linkage. With this arrangement, when the seat back pivots the arm stays essentially parallel to the seat. 
   As a general rule, prior art self-leveling armrests as well as other prior art adjustable armrests of similar complexity have been proven to be impractical for use in vehicles. For the most part, such prior art adjustable armrests are difficult to manufacture, are of relatively high cost and are of questionable reliability. Accordingly, there has been a long felt need for an easy-to-use adjustable armrest that is of a simple construction, one that can be manufactured for reasonable cost and one that can be safely used in vehicle applications, including commercial aircraft applications. The thrust of the present invention is to provide such an adjustable armrest. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a vertically adjustable armrest that provides both support and comfort to the user and one that is suitable for use in connection with various types of passenger vehicles, including commercial aircraft. 
   Another object of the invention is to provide an armrest of the aforementioned character that operates in a smooth vertical motion and one that can be stopped at any desired elevated position. 
   Another object of the invention is to provide an adjustable armrest of the character described in the preceding paragraph that includes slide means for permitting easy height adjustment of the armrest and also includes locking means for securely locking the armrest in the desired elevated position. 
   Another object of the invention is to provide an armrest construction of the class described that is of a simple, compact construction, one that is highly reliable in operation, requires minimum maintenance and one that can be inexpensively produced and easily installed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a generally perspective view of one form of the seat armrest apparatus of the invention as it appears when interconnected with a seating unit. 
       FIG. 2  is a generally perspective view of one side of a one form of the seat armrest assembly of the present invention. 
       FIG. 2A  is a greatly enlarged, generally perspective, exploded fragmentary view of the area designated in  FIG. 2  as  2 A- 2 A. 
       FIG. 3  is a generally perspective view, similar to  FIG. 2 , but showing the opposite side of the seat armrest shown in  FIG. 2 . 
       FIG. 4  is a generally perspective view of one side of the linear bearing mechanism of the seat armrest assembly. 
       FIG. 4A  is a generally perspective view, similar to  FIG. 4 , but showing the opposite side of the linear bearing mechanism of the seat armrest assembly. 
       FIG. 5  is a fragmentary, cross-sectional view of one form of the linear locking device of the assembly shown in  FIGS. 1 ,  2  and  3  of the drawings. 
       FIG. 6  is a cross-sectional view of the linear locking device of the assembly shown in  FIG. 2A . 
       FIG. 7  is a generally perspective view of the spring release mechanism of the linear locking device shown in  FIG. 6 . 
   

   DESCRIPTION OF THE INVENTION 
   Referring to the drawings and particularly to  FIG. 1 , one form of the seating unit of the present invention is there shown and generally designated by the numeral  18 . Seating unit  18 , here depicted as an airplane seat, comprises a back portion  18   a , a seat portion  18   b  and vertical side structure  20  of the character illustrated in  FIGS. 2 and 3  of the drawings. Connected to one side  20   a  of the side structure  20  is the linear locking device of the apparatus, here shown as a friction brake mechanism  24  ( FIGS. 2A ,  3  and  6 ). Connected to the opposite side  20   b  of the side structure is a linear bearing  26  ( FIGS. 2 ,  3 ,  4  and  4 A). 
   In a manner presently to be described, a vertically adjustable armrest  28  is operably interconnected with the friction brake mechanism  24  and with the linear bearing  26 . With this construction, vertical motion of the armrest is controlled by linear bearing  26 , while position control of the armrest is provided by the friction brake mechanism  24 . 
   The linear locking device, or brake mechanism  24 , which is readily commercially available from several sources, including the P. L. Porter Company of Burbank, Calif., comprises a hollow housing  30  and an elongated, vertically extending rod  32  that is slidably mounted within the housing. The brake mechanism  24  here comprises first and second coiled springs  33   a  and  33   b  that are tightly wound on the rod  32  and are fixed against axial movement relative to the housing ( FIG. 6 ). A release collar  34  is provided for acting upon the springs, thereby relaxing their grip on the rod  32  and allowing vertical movement of the housing  30  along the rod  32 . As will be discussed in greater detail hereinafter, release collar  34  forms a part of the novel release mechanism of the invention for partially unwinding the springs so that the housing  30 , along with the armrest  28  can be vertically adjusted. It is to be noted that if the rod is pushed before the springs are unwound, the springs will grip the rod even more tightly to prevent vertical movement of the housing  30  and the armrest  28 . Uniquely, brake mechanism  24  has one maximum stroke setting that can lock at any position within the travel range of the housing and has positive locking capabilities in both directions. 
   As indicated in  FIG. 6 , the distal ends of the coiled springs  33   a  and  33   b  are fixed within the housing  30 . Thus, when the release mechanism is actuated causing a force to be exerted on the actuating lever  34   a  of the collar  34 , the distal ends of the springs cannot be moved about the axis of the rod and the force imparted to the springs by the collar  34  will cause them to unwind and release their grip on the rod. However, when the actuating force on the lever  34   a  is released, the springs will immediately return to their gripping positions on the rod. 
   In the present form of the invention, the release mechanism also includes a release cable system  34   b , the operation of which causes an operating force to be exerted on the actuating lever  34   a  of the collar  34 . The details of the construction and operation of the release cable system  34   b  will presently be described. For a more complete understanding of the construction and operation of the brake mechanism, the P. L. Porter Company should be contacted. Alternatively, reference should be made to U.S. Pat. No. 3,874,480 issued to Porter et al, and entitled Friction Brake Mechanism. U.S. Pat. No. 3,874,480 is hereby incorporated by reference as though fully set forth herein. 
   Linear bearing  26  is a conventional type of linear motion device that allows motion and positioning along a linear axis. While various types of linear bearings are suitable for the present application, a linear bearing manufactured and sold by IKO Nippon Thompson Co. Ltd. of Tokyo, Japan has proven satisfactory. 
   As best seen by referring to  FIG. 2  of the drawings, linear bearing  26  here comprises a vertical slide member  36  and a carriage  38  that is connected to slide member  36  for vertical movement along a pair of spaced-apart tracks  36   a  and  36   b  between an upraised position shown by the solid lines in  FIG. 3  and a lowered position shown by the dotted lines in  FIG. 3 . Vertical slide member  36  is interconnected with the vertical side structure  22  by a plurality of spaced-apart threaded connector bolts  40  ( FIG. 2 ), while carriage  38  is interconnected with the adjustable armrest by means four spaced-apart threaded connector bolts  42 . 
   Also connected to vertical side structure  22  is biasing means for continuously urging armrest  28  toward its upraised position. This biasing means is here provided in the form of a conventional, commercially available reel-type torsion spring assembly  44  that includes a reel housing  44   a , a torsion spring  44   b  mounted within the housing and elongated, retractable, reel cable  46  having a first end  46   a  interconnected with the torsion spring  44   b  and a second end  46   b  connected to side structure  22  by means of a suitable cable anchor  48  ( FIG. 2 ). As best seen in  FIG. 2  of the drawings, reel cable  46  is entrained over an idler pulley  50  that is rotatably connected to side structure  22  and also forms a part of the biasing means of the invention. 
   In use, the armrest  28  is maintained in the upper, normal operating position shown in  FIG. 1  by the previously described biasing means. When it is desired to move the armrest into a lowered position a downward pressure is exerted on a pushbutton  53  that is mounted on the upper portion of the armrest ( FIG. 1 ). Pushbutton  53 , which, along with release collar  34 , forms apart of the release mechanism of the invention, is operably associated with a conventional release cable mechanism  55  that is carried within the armrest  28  and also forms a part of the release mechanism of the invention. As indicated in  FIG. 2A  of the drawings, the distal end  55   a  of the internal cable of the release cable mechanism  55  is received with a release housing  57  that also forms a part of the release mechanism  34 . Also received with release housing  57 , in a manner indicated by the dotted lines and  FIG. 2A , is the release lever  34   a  of the collar  34 . With this construction, the force exerted on the cable of the release cable mechanism  55  by exerting a downward pressure on the pushbutton  53  will, in a manner well understood by those skilled in the art, cause the cable to exert pressure on the release lever  34   a  causing it to move into the release position. As the release lever moves into the release position, the coiled springs  33   a  and  33   b  will be caused to unwind and release their grip on the rod  32 . 
   With the release lever in the release position, a downward force exerted on the armrest will cause the armrest to move freely downwardly. However, as previously discussed, if pressure on the pushbutton is removed, the release lever  34   a  will return to its locking position causing the torsion springs  33   a  and  33   b  to once again securely grip rod  32  and thereby prevent further downward movement of the armrest. 
   During the downward movement of the armrest, the reel cable  46  will be wound about the drum of the torsion spring assembly  44  so that, with the armrest in a downward position, a pressure exerted on the pushbutton will exert pressure on the release lever  34   a  causing it to move into the release position and thereby permit the armrest to automatically return to its upraised position due to the urging of the torsion spring  44   a  of the torsion spring assembly  44 . 
   Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.