Abstract:
A seat insert which can be inserted into an inflated or uninflated inner tube by allowing portions of the seat insert to pivot relative to each other the seat insert so that can be inserted into the tube, forced downwardly into longitudinal alignment, and locked into place in the inner tube.

Description:
This applicaton is a continuation of my co-pending application Ser. No. 806,674, filed on Dec. 9, 1985 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a recreational floating device. More particularly, the present invention relates to a collapsible inner tube seat insert. 
     In recreational water sports, one of the most popular sports is known as &#34;tubing&#34;. This sport is especially popular in rivers where moderate to small rapids are found. Of course, inner tubes are also used on other bodies of water for a wide variety of uses. 
     While inner tubes enjoy great popularity because of their availability and low cost, there are several practical drawbacks to their use. First, when floating on an inner tube, the body is commonly placed inside the inner tube, with legs and arms being placed over the top of the tube to keep the person from falling through. In order to be comfortable for long periods of time, the tube should be relatively small so that the arms can hang over the side of the tube. If the tube is too large in diameter, this may be more comfortable as far as the body not being folded into a cramped position, but the sides of the tube are farther away, and the arms become tired because the weight of the person&#39;s body must be supported farther down on the arms. Thus, it can be seen that if the tube can be deformed in an axis parallel to the body, the sides of the tube would be drawn in closer, while more room is allowed along the length of the body. 
     The second drawback to inner tubes is that the lower back and bottom of a person will protrude through the tube, which can cause problems in shallow rapids where these parts of the body may drag over rocks or other obstacles. Thus, providing a seat inside the inner tube that would support these parts of the body would avoid collisions with underwater objects. 
     Another problem with inner tubes relates to the location of their normal use. Normally, tubing is done in lakes or rivers, which can be remote from supplies of compressed air. Thus, it can be seen that if a device which can overcome the above problems is to be easily detachable from the inner tube, it should be able to be inserted and withdrawn from the inner tube while the tube is inflated. 
     Among the prior art references which propose deforming or stretching the tube along the longitudinal axis are U.S. Pat. Nos. 2,124,062 (issued to Grant, et al.), 2,080,216 (issued to Rea) and 1,869,186 (issued to Davidson). However, the Davidson reference requires that the tube be deflated before the seat can be inserted or withdrawn. Grant, et al., seems to suffer from the same limitation, as does the Rea reference. 
     In addition to the references cited, other references also disclose seat arrangements for inner tubes, including U.S. Pat. Nos. 1,743,333 (issued to Ely), 1,748,170 (issued to Chesnut), 1,764,852 (issued to Phillips), 1,793,905 (issued to Chesnut), 3,021,536 (issued to Haggerty), and 4,160,299 (issued to Hilbern). However, none of these references seek to deform the inner tube along the longitudinal axis to make it more closely fit the contours of the human body. 
     The inner tube seat insert which can overcome the above-mentioned problems should be easy to insert and remove, and should be capable of doing so with an inflated tube. This goal is best accomplished by a collapsible frame of some sort which can be placed inside the inner tube and locked into place once the desired stretching of the tube has occurred. As mentioned, Grant, et al., accomplishes the deformation and provides a seat for a child, but teaches a rigid frame which requires that the inner tube be placed around the frame in a deflated state and then inflated. A reference to McCrory, et al., (U.S. Pat. No. 4,449,473) discloses a demountable transom on an inflatable boat. Besides being for a completely different purpose, the reference contains several structural differences from the present invention which would make the structure taught by that reference incapable of accomplishing the purposes set forth below. 
     Therefore, it is the purpose of the present invention to provide an easily insertable and removable seat for an inner tube which stretches the inner tube to more closely follow the shape of the human body. 
     It is a further object of the present invention to provide a seat for an inner tube which can easily be inserted or removed without inflating or deflating the tube. 
     It is a further object of the present invention to provide a seat for inserting within an inner tube. 
     These and other objects, features and advantages of the invention will be made evident by the following detailed description of a presently preferred embodiment, of the invention. 
     SUMMARY OF THE INVENTION 
     The invention is a collapsible inner tube seat insert comprising tube engaging means mounted on the ends of insert frame bars, the insert frame bars being mounted to each other by a mounting means, the mounting means allowing the frame bars to collapse relative to each other so the tube engaging means can be removed from or inserted into an inner tube while it is inflated, and a seat mounted to one of the frame bars. The mounting means is preferably comprised of a pivot pin connecting the frame bars so they may pivot relative to each other and a locking means for holding the frame bars in place when they are pivoted into substantial longitudinal alignment. The tube engaging means is preferably comprised of a semi-circular bracket for engaging the inner portion of the inner tube. The seat insert may also comprise a foot rest attached to one of the frame bars. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top perspective view of the collapsible inner tube seat insert of the present invention showing the seat insert installed in an inner tube. 
     FIG. 2 is a cross-sectional view of the collapsible inner tube seat insert as installed in an inner tube, taken along lines 2--2 of FIG. 1. 
     FIG. 3 is a side view of the collapsible inner tube seat insert before installation in an inner tube, as seen in the cross-sectional view taken along lines 2--2 of FIG. 1. 
    
    
     DESCRIPTION OF THE INVENTION 
     The seat insert, labeled generally as 10, is shown inserted into an inner tube 12 in FIG. 1. As can be seen, the seat insert 10 deforms the inner tube 12 about the longitudinal axis to make it more comfortable for a person to fit inside the tube 12. An incidental advantage of the deformation of the tube 12 is that it makes the tube 12 more aquadynamic, so that it flows through the water more steadily. 
     The seat insert 10 is, in the presently preferred embodiment, comprised of two frame bars, including a seat frame bar 14 and a foot frame bar 16. In the presently preferred embodiment, both types of bars are constructed of hollow, square metal tubing, such as is known in the art. The seat frame bar 14 is comprised of two mirror image bars (both designated by the reference numeral 14) shaped to curve from the back of a person around the seat and straight out, as if the person were sitting on the floor. Also, the seat frame bars 14 are curved to spread out from one another to provide better support over the seat 18 and back 20. In the presently preferred embodiment, the seat 18 and back 20 are mounted to the seat frame bars 14 by a mounting means 30 which is comprised of nuts and bolts as will be explained. As the seat frame bars 14 curve upwardly into a back portion 22, a tube engaging means 24 is mounted to the end of each for holding the seat insert 10 in place in the inner portion of inner tube 12. In the presently preferred embodiment, a pair of C-shaped brackets serve as the tube engaging means 24 and each is affixed to the back frame bar portion 22 by a welded connection. The radius of the tube engaging means 24 should be large enough to fit around the tube 12, but not so large that the upper and lower portions of the tube 12 would not be gripped to hold the seat insert 10 into place. 
     A single foot frame bar 16 is provided which starts beneath the seat 18 and runs between the two seat frame bars 14 to the opposite end of the inner tube 12. The foot frame bar 16 likewise curves upwardly in a manner similar to the back frame bar portion 22, although the purpose of the curve is to provide another tube engaging means 24 to hold the opposite end of the inner tube 12, the tube engaging means 24 being attached to the foot frame bar 16 by a welded connection. 
     Further, in FIG. 1 can be seen the foot rest 26 which is mounted to the foot frame bar 16 by a strap 28. The foot rest 26 is of sufficient width so as to rest on top of the inner tube 12 instead of falling through. Thus, when the seat insert 10 is placed in the inner tube 12, the strap 28 should be of slightly insufficient length to cause the foot rest 26 to be pulled snugly down onto the inner tube 12 and therefore remain fairly rigid. Because the foot rest 26 is merely attached by the strap 28, which is looped around the foot frame bar 16, the foot rest 26 can be adjusted away from or towards the seat 18 by sliding the strap 28 to the desired position. 
     The seat frame bars 14 and foot frame bar 16 are, in the presently preferred embodiment, mounted to each other by a mounting means 30. The mounting means 30 is comprised of a pair of bolts running transversely through the seat frame bars 14 and foot frame bar 16 through holes drilled in the bars. Optional holes 32 may be provided in the foot frame bar 16 to adjust the length of the seat insert 10, so that seat insert 10 can be used on inner tubes of a variety of diameters. 
     The operation of the seat insert 10 is shown clearly in FIGS. 2 and 3. As stated, the collapsible feature of the seat insert 10 is important because seat insert 10 can be placed in the inner tube 12 with or without deflating the tube 12. Generally, the bolt comprising the mounting means 30 closest to the seat 18 is removed so that the seat frame bars 14 pivot relative to the foot frame bar 16, at least to a position as shown in FIG. 3. Once the tube engaging means 24 are positioned inside the inner tube 12, pressure can be applied on mounting means 30 in a downward fashion, as shown in FIG. 3, to stretch the tube 12 into the deformed position shown in FIGS. 1 and 2. The second bolt of mounting means 30 is then inserted when the holes of the foot frame bar 16 are aligned with the holes in the seat frame bars 14. The foot rest 26, because of the flexible strap 28, is turned sideways and rotated to fit on top of the inner tube 12 by slightly depressing the inner tube 12. 
     Of course, other means for making the seat insert 10 collapsible are feasible, such as making the frame bars telescope relative to each other. However, the frame bars should be designed so that the tube 12 can be deformed with relative ease, as the resiliency of an inflated tube 12 can be difficult to overcome without some sort of mechanical leverage, such as shown in the presently preferred embodiment, to lessen the force required to deform the tube 12. 
     Although the invention has been described in the above presently preferred embodiment, many alternatives, variations, and modifications are apparent to those of ordinary skill in the art. Those alternatives, variations and modifications are intended to fall within the spirit and scope of the appended claims.