Patent Publication Number: US-7223141-B1

Title: Stretchable foot pocket of fin

Description:
BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to fins for diving and more particularly to such a fin having a stretchable foot pocket so as to fit different individuals with various foot sizes. 
   2. Related Art 
   A conventional fin comprises a foot pocket for covering the human foot, and a blade extended forward from the foot pocket. A diver may put his or her feet in the foot pockets. In use, the diver may exert a force to vibrate the blades for propelling forward. 
   Conventionally, the foot pocket of a fin can be classified as either a pocket type (see  FIG. 1 ) or a well type without an outside counter (see  FIG. 2 ). For well type foot pocket, a strap A is provided around the heel and a snapping type fastener B is provided at a rear portion of the foot pocket for fastening the foot in the foot pocket by securing to the strap A. 
   One advantage of a fin having a pocket type foot pocket is that a person can easily find a fit fin to put his or her foot in the foot pocket. However, its disadvantage is that a number of fins with different sizes are required to be commercially available such that different individuals with various foot sizes may have a chance to select a pair of fit fins. It is often that a person wearing fins may feel discomfort if the foot pockets are too tight or too loose, resulting in an increased difficulty of moving. 
   One advantage of a fin having a well type foot pocket is that it is adapted to fit different individuals with various foot sizes. However, its disadvantage is that the fastening of the foot by the strap and fastener may become loose after a short period of time. Thus, the wearer may feel discomfort. Further, it may hook a foreign object, resulting in an increased difficulty of moving. 
   Typically, commercially available fins are formed of plastic material and have limited flexibility and resilience. Thus, continuing improvements in the exploitation of a fin having a stretchable foot pocket are constantly being sought. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention to provide a fin comprising an integrally formed foot pocket including a front vamp for receiving a front portion of the human foot, an outside counter for receiving a rear portion of the human foot, and a plurality of stretchable connection members interconnected the vamp and the outside counter; and a blade extended forward from the vamp; wherein the connection members are adapted to stretch when the human foot is inserted in the foot pocket so as to fit different individuals with various foot sizes. 
   In one aspect of the present invention the connection members, the vamp, and the outside counter are formed of the same material. 
   In another aspect of the present invention the connection members have sufficient thickness and width so as to be durable even being subjected to repeated stretching. 
   In yet another aspect of the present invention some of the connection members are formed at both sides of the foot pocket for interconnecting the vamp and the outside counter and each of the remaining at least one of connection members is formed between a sole and the outside counter for interconnection. 
   In a further aspect of the present invention some of the connection members are formed at both sides of the foot pocket for interconnecting the vamp and the outside counter, each of the remaining at least one of connection members is formed between the sole and the outside counter for interconnection, and each of the connection members formed either at both sides of the foot pocket or at the sole comprises a plurality of components. 
   The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a conventional fin having a pocket type foot pocket; 
       FIG. 2  is a side elevational view of another conventional fin having a well type foot pocket; 
       FIG. 3  is a side elevational view of a first preferred embodiment of fin according to the invention; 
       FIG. 4  is a top view of  FIG. 3 ; 
       FIG. 5  is a bottom view of  FIG. 3 ; 
       FIG. 6  is a view similar to  FIG. 3  showing the connection members being stretched slightly after inserting the foot of one person in the foot pocket; 
       FIG. 7  is a view similar to  FIG. 3  showing the connection members being stretched significantly after inserting the foot of another person in the foot pocket; 
       FIG. 8  is a top view of a second preferred embodiment of fin according to the invention; 
       FIG. 9  is a bottom view of  FIG. 8 ; 
       FIG. 10  is a side elevational view of  FIG. 8 ; 
       FIG. 11  is a bottom view of a third preferred embodiment of fin according to the invention; 
       FIG. 12  is a side elevational view of  FIG. 11 ; and 
       FIG. 13  is a perspective view of a fourth preferred embodiment of fin according to the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 3 to 5 , a fin in accordance with a first preferred embodiment of the invention comprises a foot pocket  10  including a vamp  11 , an outside counter  12 , three connection members (e.g., left, right, and bottom connection members)  13  interconnected the vamp  11  and the outside counter  12 , and a sole  14 . The foot pocket  10  is formed integrally by injection molding. Also, the connection members  13  are made stretchable. Further, the connection members  13 , the vamp  11 , and the outside counter  12  are formed of the same material. Furthermore, the connection members  13  have sufficient thickness and width so as to be durable even being subjected to repeated stretching. 
   The fin further comprises a blade  20  extended forward from bottom and two sides of the vamp  11 . The blade  20  may have a shape other than one as shown in  FIGS. 3 to 5  in other embodiments. 
   Referring to  FIG. 6 , the foot pocket  10  is slightly stretched due to the stretch of the connection members  13  (as indicated by length L 1 ) after inserting the foot of one person therein. Referring to  FIG. 7 , the foot pocket  10  is significantly stretched due to the stretch of the connection members  13  (as indicated by length L 2  which is longer than L 1 ) after inserting the foot of another person therein. The provision of the connection members  13  thus is able to enable the fin to fit different individuals with various foot sizes. 
   Referring to  FIGS. 8 and 9 , a second preferred embodiment of the invention is shown. The second preferred embodiment substantially has same structure as the first preferred embodiment. The characteristics of the second preferred embodiment are detailed below. Two connection members (e.g., left and right connection members)  13  are interconnected the vamp  11  and the outside counter  12  but no connection member being formed between the sole  14  and outside counter  12 . 
   Referring to  FIG. 10 , either connection member  13  of the second embodiment may comprise two parallel ones  13 ′ with an oval shaped space formed therebetween. This is another improvement for the purposes of aesthetic and fitting different individuals with various foot sizes. 
   Note that it is possible of having two left connection members and two right connection members. Alternatively, it is possible of having two bottom connection members. Further, the shape of the connection member is not limited to the one shown in the above embodiments. All of these fall within the scope of the invention as long as the formed fin is adapted to fit different individuals with various foot sizes. 
   Referring to  FIGS. 11 and 12 , a third preferred embodiment of the invention is shown. The third preferred embodiment substantially has same structure as the first preferred embodiment. The characteristics of the third preferred embodiment are detailed below. A connection member  13  is formed between the sole  14  and outside counter  12 . Two large openings  15  are formed at two sides of the connection member  13 . The connection member  13  is also adapted to stretch. Moreover, a plurality of holes  16  are formed at either side of the vamp  11 . Thus, the vamp  11  is adapted to stretch. The fin of this embodiment can fit different individuals with various foot sizes. 
   Referring to  FIG. 13 , a fourth preferred embodiment of the invention is shown. The characteristic of the fourth preferred embodiment is that a U-shaped lightweight strap  12 ′ is formed as a replacement of the outside counter. 
   While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.