Abstract:
A boat seat is rotatably supported on a hollow, tubular, deck-mounted support post or column by a yoke or spider. A radially movable locking plate is biased by a spring member to rotatably lock the yoke in place and a lever arm can be operated to move the locking plate in opposition to the force of the spring member out of locking engagement to permit the seat to be rotatably adjusted.

Description:
FIELD OF THE INVENTION 
   This invention is aimed at adjustable boat seats which are mounted at the top of a pedestal or pillar or post which is anchored at the bottom to a suitable support usually the deck of the boat. More specifically, it is aimed at providing a mechanism for releasably locking a boat seat in place after it has been adjustably rotated or swung in a desired direction by the occupant of the boat seat. 
   DESCRIPTION OF THE PRIOR ART 
   U.S. Pat. No. 5,882,076 dated Mar. 16, 1999 assigned to the same assignee as the instant application relates to the same function and purpose as the instant application and therefore appears to be the closest prior art that applicants are aware of. Other prior art which preceded the invention covered by the &#39;076 patent is described in the aforementioned patent and the prior art description contained therein is incorporated herein by reference for the purpose of describing the known most pertinent prior art. 
   SUMMARY OF THE INVENTION 
   To some significant degree the instant invention is similar to the invention described in the aforementioned &#39;076 patent. A yoke or spider has an upper horizontal plate member for attachment or coupling to the underside of a boat seat and an annular or tubular downwardly extending section for engaging a vertically disposed hollow pedestal or cylindrical support post or pillar. A sleeve-like insert which has teeth in the form of circumferentially spaced vertical or lengthwise slots or grooves around its exterior is located within the tubular extended section of the spider or yoke for locking onto the supporting pedestal. Ordinarily the yoke is rotatable or swivable with respect to the insert so it is free to be maneuvered to face in a direction desired by the occupant of the seat. For locking the seat when it is facing in the desired direction, there is an opening in the wall of the yoke&#39;s annular extension in which a toothed or ribbed locking plate can be moved to engage or lock onto the teeth on the aforementioned insert. A radially extending lever arm is pivotally attached to the yoke and has one end engaging the locking plate and a handle at the outer end. The locking plate is slidably engaged in the opening in the yoke annular section and is biased radially inwardly by a spring member for engaging the insert&#39;s teeth to lock the yoke against any further rotational movement with respect to the pedestal. To rotationally adjust the seat the handle of the lever arm is moved which, by mechanical arrangement, pulls or retracts the locking plate from its engagement with the insert and while held in this position the seat can be swiveled or rotated to a new position. When the handle of the lever arm is released, the spring force moves the locking plate to again engage the teeth of the insert to lock the seat in place. 
   The locking mechanism illustrated in the aforementioned &#39;076 patent has an end of the extending lever arm contacting a resilient pad on the back or the outer side of the locking plate to hold the locking plate in place with its teeth engaging the slots or grooves or spaces between the teeth on the insert. A spring member is biased to move the locking plate away from engagement. To rotate the seat, the lever arm is moved so that it no longer impinges against the resilient pad on the locking plate and the spring bias acts to move the locking plate away from its locking engagement. The present invention provides a more secure and positive locking arrangement by biasing the locking plate into secure engagement with the insert and not relying on the end of the lever arm to force and hold the locking plate into the locking engagement. Also, over a period of time a pad is likely to lose some of its resiliency so a locking arrangement which relies on a resilient pad may become less reliable. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view illustrating an elevated boat seat in which a preferred embodiment of the invention is utilized; 
       FIG. 2  is a topside view of the boat seat mounting mechanism incorporating a preferred embodiment of the invention; 
       FIG. 3  is a vertical section view illustrating the preferred embodiment of the invention with the seat in the locked condition; 
       FIG. 4  is a nonsectioned view similar to  FIG. 3  illustrating the preferred embodiment of the invention in the released or unlocked condition allowing the seat to be adjusted; 
       FIG. 5  is a horizontal section illustrating the preferred embodiment in the locked condition; and 
       FIG. 6  is a blown-apart view showing some of the detail of the mechanism of the preferred embodiment of the invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   U.S. Pat. No. 5,884,887 tided “LOCK FOR SLIDE ADJUSTMENT OF BOAT SEAT OR TABLE TOP” describes an elevated slidably adjustable boat seat with a positive locking arrangement. The instant invention can be used in conjunction with the aforementioned invention so that the elevated boat seat is not only slidably adjustable and lockable fore and aft in the manner described in the &#39;87 patent but also can be rotatably or swivably adjusted and positively releasably locked facing in the desired direction. 
     FIG. 1  illustrates a typical installation in which the instant invention is utilized. Conventionally and traditionally, a rigid circular hollow support post or column  10  extends vertically upward in a telescope arrangement from a tubular supporting pillar  9  which is attached at its base to the boat deck  7 . Usually pillar  9  contains a suitable mechanism, not shown, for adjusting the height of column  10  to raise or lower the boat seat  6 , shown in dashed line, which is attached at the top end. In some cases the boat seat may be coupled directly to pillar  9  so the boat seat is at a fixed height or elevation. In either case, boat seat  6  is coupled to its support post by a spider or yoke generally identified by reference numeral  13  which is described in greater detail hereinafter. A lever arm  11  extends outward from the underside of the boat seat which can be operated by the user to unlock or disengage the boat seat to allow it to be rotatably or swivably adjusted and to lock the seat when facing in the desired adjusted position. 
   A spider or yoke  13  is a metal casting, preferably of aluminum, and has a generally centered downwardly projecting section  14  with a centered hollow tubular section  16  for coupling to support post or column  10  and has an integrally cast horizontal upper plate  15 . As described in greater detail in the &#39;076 patent plate  15  has parallel side edges  15 A and  15 B which slidably engage in tracks, not shown, on the side edges of a plate member, not shown, attached to the underside of boat seat  6  for permitting the boat seat to be slidably adjusted fore and aft by the user. The teeth along side edge  15 B are for engaging a locking mechanism, not shown, on the boat seat plate for locking the seat in the desired adjusted forward or rearward position. 
   The exterior surface of the vertical hollow support post or column  10  has a series of closely-spaced ridges and grooves generally designated by reference numeral  17  and its internal annular surface is smooth. A hollow plastic sleeve  18  is telescoped within support column or pedestal  10  at its upper end and has an overhang designated by reference numeral  19  which extends over the upper end of column  10  and overlaps to extend downward over the exterior of a portion at the top of column  10 . The inner surface of the overhang portion  19  designated by reference numeral  20  has a series of closely-spaced vertical grooves and ridges which mate with the corresponding grooves and ridges  17  on the outer surface of column  10 . This serves to prevent insert  18  from rotating with respect to the support column  10 , i.e., the two are rotationally locked together. The outer surface of the overhang section  19  contains a series of circumferentially spaced vertical slots or grooves designated collectively by reference numeral  21  which, as will be described later, provide means for selectively locking the boat seat facing in the desired direction. 
   Yoke  13  is coupled to the support column  10  with hollow extension  16  telescoped within the interior of plastic sleeve  18  with the underside of the plate  15  effectively resting on top of the upper end of column  10 . 
   Yoke or spider  13  has a passageway generally designated by reference numeral  25  which extends radially outward in section  14 . A toothed locking plate  26  is slidably held in the opening  25  by an upper flange  26 A and is movable, as will be described later in greater detail, radially inward and outward as desired for its teeth  26 B to mesh with or disengage from the teeth  21  of the overhang section  19  of the plastic insert  18 . A bar or rod  27  extends radially outward from the back end of locking plate  26  and a coiled spring  28  in compression is wrapped around bar  27  with one end pressing against the back side or the untoothed side of locking plate  26  and the other end of the spring  28  resting against an upward extending stop  29  on spider or yoke  13 . In this fashion spring  28  is always in compression urging locking plate  26  radially inward to hold the teeth or grooves and ridges  26 B in mesh with the corresponding grooves and ridges  21  of the outer surface of the overhang  19  of the plastic insert  18 . Lever  11  has an outer handle  30  and an inner leg  31  arranged at a general right angle and is pivotally engaged at  32  with yoke or spider  13 . Extending radially outward from bar  27  is a cross pin  33  which rests in a cutout area on leg  31 . With the lever arm in the relaxed or locking position spring  28  acts on locking plate  26  to hold it firmly and securely with the teeth of locking plate  26  firmly in mesh with the corresponding ridges and slots  21 . This prevents the yoke and the attached seat from rotating with respect to the support column  10 . When the seat occupant grasps handle  30  to move lever arm  11 , in the illustrated embodiment, the handle is raised, the fulcrum action of the pivotally attached leg  31  acting on pin  33  pulls bar  27  radially outward and correspondingly locking plate  26  is moved radially outward against the force of compressed spring  28  far enough to disengage the teeth of locking plate  26  from the ridges and valleys  21  thereby permitting the yoke and the attached seat to be rotated with respect to the supporting pillar  10 . When the seat is facing in the desired direction the lever arm handle  30  is released and the spring compression takes over to move locking plate  26  radially inward against the ridges and valleys  21 . If the teeth  26 B do not mesh with the valleys or slots or grooves, the seat occupant merely shifts his or her weight enough to rotate the spider or yoke a small degree until the teeth  26 B snap into mesh to lock the yoke and seat in position. 
   As a further feature, insert  18  has a downward extending tongue section  18 A which contains an outward extending button  18 B. Button  18 B is engaged in a suitable aperture  10 A formed in column  10  as a security measure to prevent insert  18  from moving vertically with respect to column  10 . 
   As illustrated in  FIG. 3 , spider or yoke  13  preferably is formed with a diametrically opposite area  25   a  to accommodate the above-described locking mechanisms to make it convenient to provide either right-hand or left-hand lever arm control.