hereinafter , the preferred embodiments of the present invention will be described specifically with reference to the accompanying drawings . fig1 is a front view of an engaging member of a fastening device according to this embodiment , fig2 is a rear view thereof , fig3 is a side view thereof , fig4 is a sectional view taken along the line ii — ii of fig1 and fig5 is a sectional view showing an example of use style of the engaging member of the fastening device . an engaging member of a fastening device 10 according to this embodiment comprises a first flat plate portion 11 having a substantially rectangular shape , a second flat plate portion 12 of a rectangular shape having a long side having the same length as a short side of the first flat plate portion 11 and a short side substantially ⅕ of the length of the long side of the first flat plate portion 11 and a connecting portion 13 for connecting a short side edge of the first flat plate portion 11 with a long side edge of the second flat plate portion in a parallel manner and with a predetermined gap , and a side view of an entire shape thereof is substantially j shaped . according to this embodiment , a tab 14 is provided on the connecting portion 13 such that it projects outward in parallel to the first and second flat plate portions 11 and 12 . the aforementioned gap between the first and second flat plate portions 11 and 12 is determined arbitrarily depending on the thickness of a mounting portion of clothes on which the engaging member of the fastening device 10 of the present invention is to be mounted . as shown in fig2 and 3 , a number of engaging elements 15 are formed so as to project in plural rows on the surface ( rear surface of the engaging member of the fastening device 10 ) of the first flat plate portion 11 . the engaging element 15 of this embodiment is in a hook shape having a standing portion 15 a standing up from the second flat plate portion 12 as shown in fig3 and an engaging portion 15 b extending outward in a curved shape from a front end of the standing portion 15 a . in the example shown in the drawing , all of the engaging portions 15 b extend in the same direction . further , because the respective hook - shaped engaging elements 15 are formed such that front ends of the engaging portions 15 b are directed in an opposite direction to the projecting direction of the tab 14 , an engaging strength thereof with a mating fastening device member 20 having a number of loop pieces 20 a as shown in fig5 is strongest in a single direction which is opposite to the extending direction of the curved engaging portion 15 b . in addition , a continuous groove portion 11 b serving as a sewing portion is formed along an entire peripheral edge of the surface of the first flat plate portion 11 . although this groove portion 11 b is not necessary if a thickness of the first flat plate portion 11 does not affect sewing operation , it is preferable to form the groove portion 11 b even if it is a very small one , so that a sewing line can be recognized . various kinds of decorative patterns may be formed on the surface of the second flat plate portion 12 although not shown in the drawings . preferably , this pattern should be formed at the same time when this plate portion is molded , but it can be formed with various welders or prints after the plate portion is molded . a groove portion 12 b is formed on the surface of the second flat plate portion 12 in a u - shape along a sewing line corresponding to part of the aforementioned groove portion 11 b formed on the surface of the first flat plate portion 11 . that is , as shown in the drawing , the groove portion 12 b is formed continuously along the edge connected by the connecting portion 13 of the second flat plate portion 12 and both right and left edges across said edge , and a distal end thereof extends up to an edge opposite to the connecting portion 13 of the second flat plate portion 12 , serving as an open edge 12 b ′. the engaging member of the fastening device 10 of this embodiment having such a structure can be molded simply in a single process of , for example , injection molding . that is , a movable die ( not shown ) has a cavity for molding the first flat plate portion 11 , a number of the engaging elements 15 and a part of the connecting portion 13 , and on the other hand , a fixed die has a cavity for molding an external shape of the second flat plate portion 12 , decorative pattern and a part of the connecting portion 13 . additionally , a plate - like insert die having a predetermined thickness is placed between the fixed die and movable die . with injection molding die having these dies , the engaging member of the fastening device can be easily molded . since a cavity for the hook - shaped engaging element 15 cannot be cut into a single die surface because of its configuration , all or partial shape of the cavity is formed in an end face of plural thin sheet materials and by overlaying these sheet materials in an appropriate combination , the cavity for the hook - shaped engaging element 15 is formed . although a molded product may be pulled out directly from the aforementioned hook - shaped cavity with such a release member as an ejector pin ( not shown ), it may be separated easily by separating the aforementioned plural thin sheet materials in direction of sheet thickness with appropriate means . to attach the engaging member of the fastening device 10 of this embodiment having such a structure to clothes or the like , with the tab 14 outside as shown in fig5 and a face of which each of the engaging elements 15 project facing inner side of the clothes , for example , an outer skirt edge 30 a of a fly portion of a ski wear 30 shown in fig6 is sandwiched by the first and second flat plate portions 11 and 12 , the engaging member of the fastening device 10 is set up at a predetermined position and sewed along the groove portion 11 b with sewing yarn 16 . the engaging member of the fastening device 10 may be adhered with adhesive instead of sewing . in case of attaching by adhering , the groove portion 11 b is also preferred to be formed for the reason described later . on the other hand , a mating fastening device member 20 having a number of loop pieces 20 a which engages with / disengages from the engaging member of the fastening device 10 is attached on an inner skirt edge 30 b of the aforementioned fly portion by sewing or bonding corresponding to the mounting position of the engaging member of the fastening device 10 as shown in fig5 . when the upper skirt edge 30 a of clothes is inserted into a gap between the first and second flat plate portions 11 and 12 of the engaging member of the fastening device 10 of this embodiment , contrary to the engaging member of the fastening device described under the aforementioned patent number , because of substantially j - shaped cross section , the upper skirt edge 30 a of clothes can be inserted easily without opening an opening end thereof . further , because the mounting posture of the engaging member of the fastening device 10 is automatically determined by bringing an insertion end thereof into contact with an inner wall of the connecting portion 13 , the engaging member of the fastening device 10 can be attached neatly . further , because the engaging member of the fastening device 10 is fixed such that at least the edge of the clothes of the mounting portion is nipped by the first and second flat plate portions 11 and 12 and connecting portion 13 , separation never occurs between the clothes edge and each edge of the engaging member of the fastening device 10 , and further , because the tab 14 extending outward from the connecting portion 13 is provided , durability and operability for opening / closing are secured . because the extending length of the second flat plate portion 12 from the connecting portion 13 is by far shorter than the extending length of the first flat plate portion 11 , a displacement is not likely to occur between the edges of the first flat plate portion 11 and second flat plate portion 12 , and therefore , a displacement of the groove portions 11 b and 12 b for forming the sewing lines on the surfaces of the respective flat plate portions 11 and 12 can be minimized . thus , only if sewing is carried out along the groove portion 11 b of the first flat plate portion 11 as described above , the engaging member of the fastening device 10 is automatically sewed along the groove portion 12 b of the second flat plate portion 12 existing on a rear surface across a clothes , ensuring a beautiful finish . further , the groove portion 12 b for determining the sewing line formed on the second flat plate portion 12 is formed in a u - shape corresponding to the sewing line corresponding to part of the groove portion 11 b formed on the surface of the first flat plate portion 11 as described above , and a distal end of the groove portion 12 b is open . therefore , a sewing yarn to be sewn along the groove portion 11 b left in the first flat plate portion 11 is sewed directly on clothes or the like on the side of the second flat plate portion 12 . according to the prior art , when the engaging member of the fastening device 10 is separated from the loop pieces 20 a of the female engaging member of the fastening device member 20 to open the engaging member of the fastening device 10 , too much force is applied in a shearing direction on sewing yarn portion which is to be fixed perpendicular to an opening direction of a portion opposite , in particular , to the connecting portion of the second flat plate portion which is fixed by the sewing yarn along the entire peripheral edge . however , with the aforementioned structure , because the sewing yarn sewed perpendicular to the separation direction is sewed directly to clothes and the second flat plate portion 12 which should be fixed by the sewing yarn does not exist , no such extra force is applied so that the clothes or sewing yarn is unlikely to be torn . fig6 shows an appearance of a ski wear to which the engaging member of the fastening device 10 of the present embodiment and a mating fastening device member ( not shown ) are attached . when the engaging member of the fastening device 10 is pressed against the mating fastening device member 20 attached to a position corresponding to the first flat plate portion 11 of the engaging member of the fastening device 10 of the present invention , both engage each other easily so that the fly portion shown in the drawing is closed . because the engaging portions 15 b of all the hook - shaped engaging elements 15 are directed toward an opening direction of the fly portion according to this embodiment , even if a strong external force is applied in a sliding direction so as to open the fly portion , the loop pieces 20 a act in a shearing direction of the standing portion 15 a of the hook - shaped engaging elements 15 , that is , a direction of a maximum engaging strength , so that the engaging member of the fastening device 10 will not easily disengage . in the closed condition , as shown by a fading line of fig5 there is a gap d between the tab 14 of the engaging member of the fastening device 10 and an inner half portion of the fly portion , and therefore it is easy to insert a finger into this gap d thereby facilitating a separating operation for separating the engaging member of the fastening device 10 from the mating fastening device member 20 . in this closed condition , if the tab 14 is picked and the engaging member of the fastening device 10 is operated in the separation direction ( downward in fig5 ), a sufficient flexibility is ensured as compared to a case in which both surfaces of the clothes are nipped by the first flat plate portion 11 and second flat plate portion 12 like the prior art , because most attaching portion is fixed to a single surface of the clothes by the first flat plate portion 11 . as a result , smooth separation is possible . fig7 is a sectional view showing a mounting state of the engaging member of the fastening device 100 of another embodiment of the present invention . according to the drawing , the tab 104 projected from the connecting portion 13 is projected on an extension line of the second flat plate portion 12 and a projection 104 a is projected in a hook shape at a distal end to be directed toward the first flat plate portion 11 . instead of the projection 104 a , it is permissible to form a cylindrical portion . when a concave portion or a cylindrical portion is formed on the tab 104 , the tab 104 is easy to pick with fingers , thereby making the opening and closing operation accurate and easy . according to the present invention , the hook directions of all the hook - shaped engaging elements 15 do not always have to be equal as the above mentioned embodiment , but for example , it is permissible to make the hook directions of hook - shaped engaging elements 15 disposed on adjacent rows opposite to each other . in this case , a necessary engaging force can be secured in any direction on the fly portion . further , according to the present invention , it is possible to mold a flat surface 12 a leaving the groove portion 11 b on the surface of the first flat plate portion 11 , and bond with adhesive for example , an ordinary fiber - made surface engaging member of the fastening device of a similar shape as the first flat plate portion 11 and having hook pieces of ordinary monofilaments on the surface of woven or knitted base cloth to the flat surface of the first flat plate portion 11 with adhesive for example , without molding the hook - shaped engaging elements 15 integrally on the surface of the first flat plate portion 11 . fig8 shows a first modification of the aforementioned embodiment . a rib 12 c is provided on a back side of a free end portion of the second flat plate portion 12 so that it extends along an edge thereof as shown in this drawing . with such a structure , when an edge of clothes or the like is nipped between the first flat plate portion 11 and second flat plate portion 12 , the aforementioned rib 12 c holds the nipped end of the clothes by pressing , thereby preventing a displacement of the clothes or the like upon sewing . fig9 and 10 show still another modification of the present invention . according to this modification , an opening end 12 b ′ of the groove portion 12 for forming the sewing line of the second flat plate portion 12 is formed slightly thicker so as to form a reinforcing portion 12 d . a width thereof in the sewing direction is preferred to be equivalent to a single seam . by forming the reinforcement portion 12 d in this manner , it prevents a fracture of the opening edge 12 b ′ of the groove portion 12 b by a sewing thread which may occur because the opening edge 12 b ′ is thin .
this invention provides an engaging member of a fastening device integrally molded of synthetic resin which enables sewing thereof to clothes easily and accurately , ensures ease and smoothness in an operation for opening the engaging member of the fastening device even if it is molded relatively thick , and prevents too much force being applied to a sewing yarn by an external force upon the opening operation thereby ensuring durability and contributes to reduction of production cost . the engaging member of the fastening device is integrally molded with a substantially j - shaped section , consisting first and second flat plate portions substantially parallel with different lengths and made of thermoplastic synthetic resin material , whose each of end portions is connected via a connecting portion , wherein a number of engaging elements are formed on the surface of the first flat plate portion having a larger area such that they are in an upright position and a groove - like sewing line is formed along an entire peripheral edge portion thereof , a groove - like sewing line whose end portions are open is formed corresponding to part of the sewing line formed on the first flat plate portion on the second flat plate portion having a smaller area , and a tab made of the same resin material is molded integrally on the connecting portion so as to project outward from the connecting portion in parallel to the flat plate portions .