Pressure sealing slide fastener
United States Patent [191 Takamatsu Apr. 1, 1975 [21] Appl. No: 439,057  
 [30] Foreign Application Priority Data Feb. 6. 1973 Japan 48-16118 [52] US. Cl 24/205.1 R Int. Cl A44b 19/32 Field of Search 24/205.1 R  
 [56] References Cited UNITED STATES PATENTS 2,7-16 l 13 5/1956 138K127 6/1959 2.909.823 Ill/1959 3.082.501 3/1963 3.104.437 9/1963 3.121.929 Z/1969 Heimberger 24/205.l C Frohlich 24/205.l C  
 Primary Evaminer-Bernard A. Gelak Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara &amp; Simpson [57] ABSTRACT A pressure-sealing type of slide fastener is provided for use on closures such as diving suits, tents and the like wherein complete fluid-tightness is required. The fastener has a pair of opposed stringer tapes whose adjacent longitudinal marginal edge portions are tilted upwardly toward each other and held in abutting relation substantially in the fashion of a rafter when the fastener is closed by manipulating a slider. In normal closed condition of the fastener, a free space is maintained between the marginal edge portions of the respective tapes and the fastener elements attached thereto, whereby the tapes are allowed to flex in response to changing external pressure.  
 5 Claims, 3 Drawing Figures PATENTED APR H975 3.874.037  
 11 15 11b 12b Q 15 WWI/l PRESSURE SEALING SLIDE FASTENER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to sliding clasp fasteners and has particular reference to a fastener of the pressure sealing type in which adjacent longitudinal marginal edges of a pair of opposed stringer tapes are hermetically sealable when the fastener is closed.  
 2. Prior Art Many pressure sealing slide fasteners have been proposed for use on diving suits and the like wherein absolute air-tightness and water-proofing are mandatory. Such known sealing fasteners were constructed such that oppositely disposed stringer tapes usually made of rubber or similar elastic materials suitable for fluidsealing purposes are brought resiliently into abutting relation along their adjacent longitudinal edges as the fastener elements are intermeshed to close the fastener. Due to these opposed tape edges being pressed firmly against each other. the movement ofa slider therealong was rendered heavy and sluggish. Another drawback of the prior art devices is that the adjacent marginal tape edges which have been brought resiliently together are prone to spread apart under the influence of increased e\ternal pressure.  
 SUMMARY OF THE INVENTION It is therefore an object of the invention to provide an improved pressure sealing slide fastener which incorporates structural features designed to eliminate the foregoing drawbacks of the prior art; more specifically. to render the movement of the slider light and smooth and further to maintain complete fluid-sealing effect against the inlluence of changing external pressure.  
  According to the invention. a pressure-sealing slide fastener comprises flat stringer tapes each including an integral web portion and a marginal edge portion which extends at an angle therefrom beyond the center axis, the marginal edge portion resting on a sloping portion on each of the interlocking fastener elements in its free state and being raised slightly therefrom when the elements are interlocked.  
  This object and other features of the invnntion will appear clear from the following description taken in connection with the accompanying drawings which illustrate by way of example a preferred embodiment of the invention and in which like reference numerals refer to like parts throughout the same.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a pressure sealing slide fastener constructed in accordance with the invention and shown in closed disposition;  
 FIG. 2 is a transverse cross-sectional view ofthe same with a slider mounted thereon: and  
  FIG. 3 is a transverse cross-sectional view showing one of the two fastener stringers.  
 face thereof a series of interlocking fastener elements 13. Each individual fastener element 13 has an engaging portion 13a adapted to engage in interlocking relation with that of theopposed, mating element and a mounting portion 13b adapted to be united to one face of the stringer tape ll,( 12) at a region immediately adjacent a longitudinal marginal edge portion hereafter described. The element 13 is further provided with a slope portion 13c extending from the flat mounting portion 131) upwardly toward and terminating short of the longitudinal center axis of the fastener 10 which is indicated in chain-dotted line AA in FIG. 2 and which is in registry with the center axis of the engaging portions 13a of the elements 13.  
  Each stringer tape 11,( 12) comprises a flat web portion 11u,(12a) and a longitudinal marginal edge portion llb,(l2b) which is directed upwardly along the slope portions 136 of the fastener elements 13 but is disposed for free movement relative thereto may be seen from FIG. 2. The marginal edge portions l1b,(12b are thus tilted upwardly toward each other and each extend slightly beyond the center axis AA shown in FIG. 3, so that they can abut intimately against each other substantially in the form of a rafter when the fastener elements 13 are interlocked by a slider 14 to close the fastener 10 in a manner as illustrated in FIG. 2. To facilitate resilient flexing ofthe adjacent marginal edge portions 1111.121) during the closing and opening of the fastener 10 or when the stringer tapes 11,12 are subjected to increased external pressure. there is provided a longitudinal groove 15 formed in the upper surface of each stringer tape and extending parallel with the longitudinal axis of the fastener 10 in a position defining the borderline between the free marginal edge portion 11!),(1212) and the flat web portion 11a.(12u). To this end. the marginal edge portions 11b.12b may be preferably reduced in thickness as compared to the web portions 11u,l2u shown.  
  In normal closed disposition of the fastener 10, there should preferably be a clearance or free space 16 maintained between the lower surfaces of the adjacent marginal edge portions 1117,1212 that have been brought together and the apex of the slopes 130, which clearance or free gap 16 serves to allow merged marginal edge portions 1117,1212 to move flexibly therein in response to changing external pressure. This arrangement permits the fastener 10 to yield resiliently and flexibly to such external pressure exerted in variable degrees thereupon which would otherwise force the opposed stringer tapes 11,12 to split apart along the adjacent marginal edge portions 1111,1217.  
  The sealing structure herein-above described is advantageous in that the adjacent marginal edge portions 1112.12!) at their free edges are allowed to increase the area of their contact surfaces 17, hence in bondage substantially in proportion with increasing external pressure. Thus, in accordance with the invention, it is rendered possible to maintain sealing ofthe fastener 10 against changing external pressure and further to facilitate the sliding movement of the slider.  
  Terms such as upwardly used herein are used for reference purposes without regard to the direction of gravity.  
 What is claimed is:  
 1. A pressure-sealing slide fastener comprising:  
 a. a pair of opposed stringer tapes each including 1. a web portion and 3 2. a marginal edge portion connected thereto and extending at an angle therefrom beyond the center axis of the fastener in its free state: b. a series of interlocking fastener elements each ineluding l. an engaging portion; 2. a flat mounting portion bonded to said web portion. and 3. a sloping portion contiguous to said flat mounting portion and supporting said marginal edge portion in its free state; and c. said marginal edge portions being engageable edgewise with each other and tiltable away from the sloping portion of said elements to increase the angle away from the plane of said tapes as said elements are interlocked.  
  2. A slide fastener according to claim 1 in which said web portion and said marginal edge portion are flat.  
  3. A slide fastener according to claim 1 in which said web portion and said marginal edge portion are each of uniform thickness throughout a substantial portion of their extent.  
  4. A slide fastener according to claim 3 in which said marginal edge portion is at all points of lesser thickness than said web portion.  
  5. A slide fastener according to claim 1 in which said web portion and said marginal edge portion comprise integral portions of said tape.