This invention relates generally to hot tubs and spas, and more particularly to removal systems adapted for removing covers therefrom. 
Spa cover removal systems and mechanisms are known in the art.  Such mechanisms vary widely in complexity, ease of operation and cost of manufacturing.  In recent years, the rise in popularity of spas, commonly referred to as hot tubs, has hastened the development of spa covers and removal apparatus therefor.  One early design for cover removal is disclosed in U.S. Pat.  No.  4,857,374 issued to Perry (Gary L.) in 1989.  The Perry design employs gas springs that extend from the sides of a spa to a spa cover that is hinged to the rear of the spa.  In this way, the gas springs assist the user to pivot the cover to a vertical position, away from the top of the spa. 
U.S. Pat.  No.  4,853,985 issued to Perry (Cliff R.) in 1989 shows a cover assembly for use with a spa.  The cover assembly includes a cover member mounted for rotational movement to the spa structure by mounting arms.  The mounting arms are arranged relative to the cover member so that the cover member travels along a path from a covering position to an open position.  Additionally, the ""985 device includes tension springs.  Because of the arrangement of the mounting arms and their attachment to the spa cover, the design is not easily adaptable for use with spa covers that fold back to expose only a portion of the spa. 
U.S. Pat.  No.  4,991,238 issued to Forrest in 1991 shows a spa cover lift that includes one or more struts for positioning a movable frame adapted for pivotable attachment to the side of a spa.  The lift includes apparatus for receiving a spa cover from the spa and retaining the cover adjacent the movable frame.  The struts are operable to displace the movable frame to an extended position to provide a surface onto which a spa user can slide a spa cover.  Because the Forrest device requires that the entire spa cover be moved rearward onto the movable frame, a single user could find it difficult to slide a large heavy cover. 
U.S. Pat.  No.  5,131,102 issued to Salley in 1992 shows a device for use in conjunction with a spa cover mounted for pivotal movement to facilitate the removal of the cover away from the vicinity of the spa when the same is in use.  A bridge arm supported by two side arms is pivotally attached to a base.  The bridge arm can be pivoted into position adjacent the spa cover.  With the spa cover folded over, the bridge arm is pivoted clearly away from the spa.  The arrangement of the ""102 device is such that it provides support to the spa cover only at the cover""s folding point during the removal process.  Accordingly, a portion of the cover slides over the spa as a user operates the device to remove the cover. 
U.S. Pat.  No.  5,471,685 issued to Cross in 1995 shows a support for a cover of a hot tub spa having a pair of roller support arms, each having a pivotal connection for securing it to the spa.  The pivotal connections each comprise an attachment member for mounting on a vertical outer wall of the spa, with a hinge connecting the support arm to its attachment member for pivotal movement between operative and inoperative positions.  Like the Forrest device, the entire spa cover must be moved rearward onto the frame. 
U.S. Pat.  No.  5,517,703 issued to Ouelette in 1996 shows a lifting mechanism for removing and restoring a hinged spa cover from a spa tub.  Two tubular brackets are cojoined so that base members on the brackets are aligned parallel, adjacent to one end of the spa, and arms on the brackets extend along opposite sides of the spa.  The cojoined base members are pivotally mounted so that the lifting arms are rotatable between a first lowered position and a second raised position.  Support beams are connected to the lifting arms over which the hinged sections of the cover are foldable when the arms are in the first position allowing the cover to be lifted clear of the spa when the arms are moved to the second raised position.  Like the Salley device, the ""703 cover removal apparatus, during the removal process, provides support to the spa cover only at the cover""s folding point. 
U.S. Pat.  No.  5,584,081 issued to Ouelette in 1996 shows a lifting frame for a hinged spa cover having a pair of adjustable lifting arms pivotally mounted adjacent the side walls of a spa.  A U-shaped foot actuated lever is connected to the lifting arms with the base of the lever extended across one end wall of the spa.  The upper part of the arms are equipped with one or more supports that are adjacent to and parallel with the cover hinge whereby the cover is foldable over the support or supports when the lifting arms are in a first position.  The foot lever is elevated when the lifting arms are in the first position, and depressing the lever causes the arms to be rotated to a second position whereby the folded cover is supported in a vertical position adjacent one end wall of the spa.  Like the earlier Ouelette invention, the spa cover is supported only at its folding point. 
U.S. Pat.  No.  5,634,218 issued to Ouelette in 1997 shows a lifting frame for a hinged spa cover having a pair of adjustable lifting arms pivotally mounted on or adjacent to a side wall of a spa.  The upper part of the arms are equipped with one or more supports that are adjacent to and parallel with the cover hinge with the cover being foldable over the support or supports when the lifting arms are in a first horizontal position.  Rotation of the frame causes the folded cover to be rotated to a second, vertical position adjacent one end wall of the spa.  Similar to the other Ouelette devices, this design provides support to the spa cover only at its folding point. 
U.S. Pat.  No.  5,644,803 issued to Wilson in 1997 shows a spa support assembly that is provided with a plurality of support arms having upper and lower ends with the lower ends pivotally attached to an external surface of the spa side wall for pivotal rotation of the upper ends of the support arms through an arc from a point above and adjacent to the side wall to a point away from the side wall at a point where the upper ends of the support arms are within the generally horizontal plane defined by the top surfaces of the side walls and at a distance away from the side wall.  Like the prior ""238 and ""685 patents, the Wilson device requires that the user slide the spa cover rearward over the spa during the removal process. 
While most of the above noted designs assist in the removal process of a spa cover from a spa, they typically do not provide a simple, safe, inexpensive and adjustable means to remove and support the spa cover in a compact position which allows unimpeded access to the spa.  Accordingly, a need remains for a spa cover removal apparatus that facilitates the easy removal of a spa cover by a single user which is safe, and easy to install and use. 
One object of the present invention is reduce the effort required to remove a spa cover from a spa. 
A second object is to facilitate the removal of a spa cover from a spa by only one person. 
Another object is to protect expensive spa covers by simplifying the removal process thereof from a spa. 
Yet another object is to reduce the expense of heating water in spas by promoting the use of spa covers that are easily removed by one person. 
A further object is to increase the safety of using a cover removal apparatus. 
Still another object is to fully support a spa cover in a compact manner thereby minimizing the space taken by the stowed cover following the removal process. 
The invention is a spa cover removal apparatus for assisting a person in the repositioning and removal of a spa cover from a spa.  Typically, spa covers are constructed such that they include opposing left and right cover side surfaces.  Additionally, spas are typically arranged to include a cabinet having a back side disposed between opposing left and right spa sides, wherein the back side is commonly disposed above a recessed spa base.  In the present invention, the spa cover removal apparatus comprises a pivot frame assembly having a pair of elongate side arms spaced apart to receive opposing cover side surfaces between the same for rotatably supporting the spa cover.  Fixed to the spa is a stationary base, for pivotally supporting the pivot frame assembly.  For this purpose, the stationary base is disposed under the pivot frame assembly. 
This arrangement enables the spa cover to shift from a first horizontal covering position over the spa, to a second stowed position adjacent the back side of the spa as a rearwardly directed force is applied to the spa cover.  Accordingly, the spa cover moves rearward and pivots relative to the side arms while the pivot frame assembly simultaneously pivots relative to the stationary base, about a substantially horizontal base pivot axis.  In addition, a slide lock bar extends from the pivot frame assembly for sliding attachment to the spa side to restrict the spa cover against further movement once the same reaches the second stowed position. 
In another aspect of the invention, a portion of the pivot frame assembly extends in a downward direction from the pivot axis, in an opposing direction from the side arms.  In this way, the pivot frame assembly can engage the stationary base for restricting further pivotal movement of the pivot frame assembly when the same moves to the second stowed position. 
The foregoing and other objects, features, and advantages of this invention will become more readily apparent from the following detailed description of a preferred embodiment which proceeds with reference to the accompanying drawings, wherein the preferred embodiment of the invention is shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention.  As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention.  Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.