Abstract:
Swimming goggles include an elastic head strap. Free ends of the strap are guided through first guiding holes and then through second guiding holes. A stopper member is inserted into a gap defined between a peripheral wall of the second guiding hole and the strap. The swimming goggles thus constructed allow a length of the strap once adjusted to be maintained during repeated use of the swimming goggles.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to swimming goggles used by swimmers or divers. 
     Japanese Utility Model Registration Gazette No. 2570206 discloses swimming goggles in which an elastic head strap made of rubber has its opposite free ends guided through strap guiding holes provided at outer ends of respective lens frames from the rear toward the front so that the head strap can be fastened around a goggles&#39; wearer. These free ends are then folded twice or more along supports provided on the outer ends of the respective lens members and thereafter guided through the strap guiding holes from the front toward the rear. Within the strap guiding holes, two sections of the strap are placed against each other and thereby frictionally restrict a relative movement of these two sections. In this manner, the strap is prevented from falling off from the strap guiding holes even when the strap is fastened around the wearer&#39;s head and pulled rearward. Thus the head strap is adjusted to a desired length relative to the swimming goggles. 
     However, the known swimming goggles are not free from a problem such that the free ends of the strap which have been guided through the strap guiding holes may be moved little by little in a direction of falling off every time the head strap contracts during its repeated expansion and contraction. Consequently, after the swimming goggles have been repeatedly put on and taken off, the head strap once adjusted to the optimum length for fitness around the wearer&#39; head may slacken. To correct such inconvenient situation, the length of the head strap must be often readjusted. Certainly, it is possible to inhibit the undesired movement of the free ends by forcibly inserting wedge-like stopper members between peripheral edges of the respective strap guiding holes and the free ends guided through the strap guiding holes, respectively. However, the strap becomes thinner as the strap is stretched and the effect of the stopper members is correspondingly deteriorated and therefore the length of the strap must be readjusted in this case also when the swimming goggles are used for a long period. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide swimming goggles that make it unnecessary to readjust the length of a strap thereof. 
     According to this invention, there is provided swimming goggles having a pair of first strap guiding holes formed on transversely opposite sides thereof and a head strap having longitudinally opposite free ends each adapted to be guided through each of the first strap guiding holes from the rear toward the front, then to be folded twice or more along strap supports formed on the opposite sides and thereby to be length-adjustably fixed to the opposite sides, wherein: 
     the free end folded twice or more along the strap supports is guided from the front toward the rear through a second strap guiding hole provided independently of the first guiding hole and a stopper member is detachably inserted into a gap defined between a peripheral wall of the second guiding hole and the free end in order to prevent the end from falling off from the second guiding hole from the rear toward the front. 
     According to one preferred embodiment, the free end extending from the front toward the rear after being folded twice or more along the strap supports is brought in close contact with the portion of the head strap having already left the first guiding hole and thereafter guided through the second guiding hole spaced from the portion of the head strap. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a pair of swimming goggles according to this invention; 
     FIG. 2 is a sectional view taken along a line II—II in FIG.  1  and viewed in the direction as indicated by arrows in the same figure; and 
     FIG. 3 is a view similar to FIG. 2 showing a lens assembly and a strap retaining member as they are detached from each other. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Swimming goggles  1  shown by FIG. 1 in a perspective view are arranged so that a pair of lens assemblies  3 , each comprising a lens  2 A and a frame  2 B which are integrally molded, are joined together by a bridge  4  that, in use, lies in front of a wearer&#39;s nose, on one hand, and by a head strap  6  adapted to be fastened around the wearer&#39;s head, on the other hand. Each of the lens assemblies  3  is made of hard plastic and is formed at its transversely inner end  7  lying adjacent the nose of the wearer with an end wall  40  protruding forward, by which the bridge  4  is detachably locked to the lens assemblies  3 . At an outer end  8  of the lens assemblies  3  lying nearer to the back of the wearer&#39;s head, the head strap is length-adjustably held by a strap retaining member  10  which is provided separately of the lens assembly  3 . A flange  11  (See FIG. 2) formed around the lens assembly  3  carries an annular cushioning pad  12  made of soft and elastic material. 
     FIG. 2 is a sectional view taken along a line II—II in FIG.  1  and viewed in the direction as indicated arrows in the same figure, in which the cushioning pad  12  is indicated by chain lines. At the outer end  8  of the lens assembly  3 , a flange-like portion  13  extends laterally from the frame  2 B and the strap retaining member  10  is attached to the upper side of this flange-like portion  13  so that a peripheral wall of the retaining member  10  is placed at a part thereof against the frame  2 B. The flange-like portion  13  is formed at its location near the frame  2 B with an inner strap guiding hole  16  and its location remote from the frame  2 B with an outer strap guiding hole  17 . On the other hand, the strap retaining member  10  is formed with a pair of arms  18  which are opposed to each other in the vertical direction as viewed in FIG.  1 . The strap retaining member  10  is additionally formed with inner and outer strap supports  21 ,  22  extending in parallel to each other in the vertical direction also as viewed in FIG.  1 . The pair of arms  18  as well as the inner and outer strap supports  21 ,  22  are transversely spaced from each other, respectively, so that the strap  6  can be guided between the pair of arms  18  as well as between the inner and outer strap supports  21 ,  22 . 
     The head strap  6  is elastic and made of rubber. After having been guided through the inner guiding hole  16  of the lens assembly  3  from the rear of the lens assembly  3 , the free end  23  of the head strap  6  is guided through a gap defined between the arms  18  and the outer support  22 , a gap defined between the outer support  22  and the inner support  21  and a gap defined between the inner support  22  and the peripheral wall  14  of the strap retaining member  10  in this order. Thereafter, the free end  23  is turned over and guided through the outer guiding hole  17  of the flange-like portion  13  and extend rearward. 
     With this arrangement, there is no apprehension that the head strap  6  might easily fall off from the lens assembly  3  even when the strap  6  is pulled rearward in the direction as indicated by an arrow X. This is because that the strap  6  is folded twice or more by the inner and outer supports  21 ,  22  of the strap retaining member  10 , on one hand, and turning over of the free end  23  presses two sections of the strap  6  against each other at a location  26 , on the other hand. In addition, a wedge-shaped stopper  27  formed integrally with the arms  18  of the strap retaining member  10  may be inserted, more preferably forced into a gap defined between a peripheral wall  24  of the strap guiding hole  17  and the strap  6  to ensure that the strap  6  is more reliably prevented from falling off from the lens assembly  3 . Even if the strap  6  repeats its expansion and contraction in the direction as indicated by the arrow X and in the reverse direction, respectively, the portion of the strap  6  repeating such repeated expansion and contraction is kept free from frictional contact with a portion  28  of the strap  6  which is clamped by the wedge-shaped stopper  27 . This means that the stopper  27  is substantially free from a force tending to pull the strap  6  forward out from the outer guiding hole  17 . Accordingly, the length of the head strap  6  once adjusted is well maintained even after the swimming goggles  1  have repeatedly been put on and taken off. 
     FIG. 3 is a view similar to FIG. 2, in which the strap retaining member  10  has been detached from the lens assembly  3  and in which the head strap  6  is indicated by chain lines. With the strap retaining member  10  being at the position relative to the lens assembly  3  as shown, the head strap  6  may be guided through the flange-like portion  13  and the retaining member  10 . The strap retaining member  10  is placed upon the flange-like portion  13  as the strap  6  is pulled in the direction as indicated by the arrow X. Thereupon, the wedge-shaped stopper  27  of the strap retaining member  10  is forced into the outer guiding hole  17 . 
     While the strap retaining member  10  and the lens assembly  3  are illustrated as being provided separately from each other, it is also possible without departing the spirit and scope of this invention to unitize strap retaining member  10  and lens assembly  3 . It should be understood that a member corresponding to the wedge-shaped stopper  27  should be provided as a separate member when the members  10 ,  3  are unitized. A thickness of the wedge-shaped stopper  17  is preferably dimensioned so that the stopper  17  can be pressed against the strap  6 . 
     With the swimming goggles according to this invention, the length of the head strap once adjusted is well maintained even after the swimming goggles have been repeatedly put on and taken off. This is achieved by the unique arrangement of this invention such that the portion of the head strap destined to repeat expansion and contraction is guided through the guiding hole provided independently of the guiding hole through which the portion of the strap to be fixed is guided.