Sliding clasp coupling elements
United States Patent [191 Takamatsu [451 Apr. 1, 1975 1 SLIDING CLASP COUPLING ELEMENTS [75] Inventor: Ikuo Takamatsu, Uozu, Japan [73] Assignee: Yoshida Kogyo Kabushiki Kaisha,  
 Tokyo, Japan [22] Filed: July 31, 1973 [21] Appl. No.: 384,176  
 [30] Foreign Application Priority Data Aug. 3, 1972 Japan 47-91399 [52] US. Cl. 24/205.13 R, 24/205.16 R [51] Int. Cl A44b 19/04 [58] Field of Search 24/205.13 R  
 [56] References Cited UNITED STATES PATENTS 3,121,929 2/1964 Morin 24/205.13 R 3,302,259 2/1967 Waldes 24/205.l3 R  
 FOREIGN PATENTS OR APPLICATIONS 571,691 9/1945 United Kingdom 24/205.13 R  
 Primary Examiner-Bernard A. Gelak Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato; Bruce L. Adams [57] ABSTRACT There is disclosed -a sliding clasp fastener comprising a pair of oppositely disposed stringer tapes each carrying along their&#39;respective longitudinal edges on one surface a series of discrete molded or die cast elements.  
 Each element is provided in one surface with a recess or indent disposed for reception therein of a marginal edge portion of the stringer tape with a view to reducing the overall thickness of the fastener.  
 8 Claims, 5 Drawing Figures SLIDING CLASP COUPLING ELEMENTS BACKGROUND OF THE INVENTION This invention relates to sliding clasp fasteners having opposed stringer tapes of the type wherein the fastener elements are attached by injection or die casting to one surface of the respective stringer tapes.  
  There were known many fasteners carrying molded or die cast fastener elements of a discrete formation which are fixed in position with their leg portions mounted astride of the upper and lower surfaces of the stringer tapes along a longitudinal edge thereof. On account of the fastener elements being exposed on both surfaces of the stringer tapes, the conventional fasteners of this type were open to objection when used on garments such as shirts, ladies one-piece wears and the like where the fastener elements are disposed in contact with the skin of the wearer.  
  More recent improvements have been introduced wherein the fastener elements are mounted and fixed on only one surface of the stringer tapes so as to leave the other surface, facing toward the garment, free of fastener elements. However, such one-sided fasteners have suffered from the disadvantages that the protrusion of fastener elements above the one surface of the stringer tapes is literally so much greater, which in turn reduces the strength of adhesion of the fastener elements relative to the stringer tapes and which further creates the tendency of such protruding elements to catch the garment or other objects thereby damaging the latter or the fastener itself. A simple solution to this problem would be to reduce the thickness of the fastener elements as measured in a plane perpendicular to the plane of the fastener. However, too thin fastener elements would result in reduced strength of coupling between the elements and would be liable to disengagement from one another.  
 SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide improved sliding clasp fasteners carrying on one surface a series of molded or die cast coupling elements, which elements incorporate structural features to render the same relatively thin yet without sacrifice in their coupling strength.  
  Another object of the invention is to provide improved sliding clasp fasteners of the type described whose elements are secured firmly into position on one surface of the fastener.  
  These and other objects and features of the invention will appear clear from the following detailed description thereof taken together with the accompanying drawings wherein like reference numerals denote like or corresponding parts throughout the several views and wherein:  
 BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:  
  FIG. 1 is a plan view of a sliding clasp fastener embodying the invention;  
  FIG. 2 is a sectional view taken along the line IIII of FIG. 1;  
  FIG. 3 is a perspective view of the reverse side of the fastener shown in FIG. 1;  
  FIG. 4 is a perspective view ofa modification according to the invention; and  
  FIG. 5 is a sectional view of a half portion of another modified fastener according to the invention.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and FIGS. 1 to 3 in particular, there is shown a sliding clasp fastener 10 which comprises a pair of oppositely disposed stringer tapes ll, 11 each carrying along their respective longitudinal edges l2, 12 on one surface a series of molded or die cast discrete coupling elements 13. Each element 13 consists of an upper coupling member 14 including at opposite sides protuberances l5, l5 and reduced neck portions or sockets 16, I6 engageable with the protuberances l5, 15 of the upper coupling member 14 on the companion stringer tape to establish a coupling engagement of the elements 13 in a horizontal direction and a lower coupling member 17 substantially rectangular in shape with its outer end terminating short of the outer end of the upper coupling member 14 and engageable with the lower face of the upper coupling member 14 on the companion tape to establish a coupling engagement in a vertical direction, as seen in a conventional structure. The coupling elements 13 further consists of a leg portion 18 extending opposite to the coupling members 14, 17 and disposed for attachment to the longitudinal edge 12 of the tape 11.  
  According to the invention, there is provided a cutaway recess or indent 19 in, the lower surface of the leg portion 18, which recess is defined by a vertical wall 20 adjacent the lower coupling member 17 and a bottom wall 21 of the leg portion 18. The indent 19 has a depth approximating the thickness of the stringer tape 11 such that the end face 22 of the longitudinal edge 12 of the tape 11 is held in abutting relation to the vertical wall 20 and the upper surface 11 of the tape 11 is superposed on and affixed to the bottom wall 21 of the leg portion 18, thus securing the elements 13 firmly through two contact surfaces into position on the fastener 10. If necessary and when providing increased adhering strength between the tape 11 and the element 13, there may be provided a bead-like ridge 23 projecting longitudinally of the tape 11 for engagement in a groove 24 formed in the bottom wall 21 of the leg portion 18. To assure affixation of the elements 13 with greater stability to the respective tapes 11, II, the elements 13 may be stitched as at 25 along the longitudinal edges 12, 12, for which purpose there is provided a stitch-receiving recess formed in the upper surface of each element 13 as shown, whereby the stitchings 25 run substantially parallel with the longitudinal ridge 23.  
  Referring to FIG. 4, there is shown a modified form of element 13 wherein the lower coupling member 17 is triangular in shape with its apex 26 registering with the outer end of the upper coupling member 14. Another feature of this embodiment is found in the provision of a larger bead-like ridge 23 and a correspondingly large groove 24 for embracing the same, whereby sufficient adhesion is obtained between the element and the tape without the necessity of providing stitches 25.  
  FIG. 5 shows another moodification wherein the lower coupling member 17 has a height H greater than the thickness T of the tape 11.  
  It will redound to the advantage of the invention to note that in spite of the leg portion 18 of the element 13 being reduced in thickness to render the fastener relatively thin for the purposes hereinbefore stated, the strength of coupling engagement between the opposed elements 13 is not affected because sufficient dimensions of the coupling members l4, 17 are sustained, and that the elements 13 are firmly secured into position on the tape 11 by virtue of the dual surface contact provided by the indent 19 as aforesaid.  
 What is claimed is:  
  1. A sliding clasp fastener comprising, a pair of opposed stringer tapes, and a plurality of coupling elements disposed along and secured to a pair of adjacent longitudinal edge portions of said stringer tapes on corresponding upper surfaces of said tapes, wherein each of said coupling elements comprises;  
 an upper coupling member having an upper surface;  
 a lower coupling member underlying said upper coupling member and having a lower surface, said upper surface and said lower surface defining a thickness of said coupling element; and  
 a leg portion integral with said upper coupling member and said lower coupling member and extending therefrom, said leg portion having an upper surface even with said upper surface of said upper coupling member, and a lower surface, said leg portion having a thickness substantially equal to said upper coupling member thickness, said lower coupling member terminating at a rear edge portion, said rear edge portion together with said lower surface of said leg portion defining an indentation having a depth approximately equal to a thickness of said stringer tapes and comprising a surface contacting the upper surface of one of said tapes and said edge portion contacting a longitudinal edge of said one of said tapes.  
  2. A sliding clasp fastener according to claim 1 wherein said coupling elements are die-cast.  
  3. A sliding clasp fastener according to claim 1 wherein said coupling elements are molded.  
  4. A sliding clasp fastener as defined in claim 1 wherein said leg portion has formed in the leg portion upper surface a recess for accommodating stitches that secure the elements to the tape.  
  5. A sliding clasp fastener as defined in claim 1 wherein there is provided a groove in the first surface of said indentation for engagement with a correspondingly shaped bead-like ridge projecting from the upper surface of the tape.  
  6. A sliding clasp fastener as defined in claim 1 wherein said lower coupling member is rectangular in shape and has an outer end terminating short of an outer end of said upper coupling member.  
  7. A sliding clasp fastener as defined in claim 1 wherein said lower coupling member is triangular in shape and has its apex registering with the outer end of said upper coupling member.  
  8. A sliding clasp fastener as defined in claim 1 wherein the thickness of said lower coupling member is greater than the thickness of the stringer tape.