STRAP FASTENER

Abstract: A strap fastener (10) includes a fastener body (11) on which a strap (S) is retained, and a socket member (13) adapted to be mounted on the fabric (C) of a bag to retain the fastener body (11) for connecting the strap (S) to the bag. The fastener body (11) has a plug (18) with an enlarged head (18 b ) snappingly receivable in a stepped bore (35) formed in the socket member (13). The fastener body (11) is rotatable about the axis of the plug (18).with respect to the socket member (13). With this construction, the strap (S) is connected to the bag with utmost ease and can be adjusted in a desired posture to suit with the physical characteristics of the user.

Description: The present invention relates to a strap fastener for use on shoulder bags, rucksacks, school knapsacks or other bags for connecting the end of a belt or strap to the body of a bag. Straps on knapsacks in common use are secured at their opposite ends in place by sewn seams or rivets via suitable covering tabs as illustrated in Figure 18 of the accompanying drawings in which the knapsack is indicated by K, the strap by S and the tabs by T. With the straps thus permanently secured to the fabric or leather web of the knapsacks, it is literally difficult to replace the straps per se when worn or damaged without tearing the tabs off, demanding purchase of a new whole knapsack. The prior art strapped knapsack has a further drawback in that because they are fixedly connected, the straps would be swerved to the sides if worn by a wide-shouldered person as indicated by phantom lines in Figure 18 or would otherwise fail to fit comfortably to wearers of different constitution. The present invention seeks to provide means for eliminating the foregoing difficulties of the prior art and to this end, more specifically to provide a strap fastener which will enable removal of worn or damaged straps and attachment of new counterparts with utmost ease. The present invention further seeks to provide a strap fastener which will enable adjustment of the straps on for example a knapsack to fit different physical characteristics of the users. According to the present invention, there is provided a strap fastener for connecting a strap to the fabric of a bag, comprising: a socket member adapted to be mounted on the fabric of the bag and having a stepped bore; and a fastener body having means for retaining the strap, and a plug projecting from the back of said fastener body, said plug including an enlarged head snappingly fittable in said stepped bore in said socket member to couple said fastener body with said socket member, said fastener body in coupled condition being rotatable about the axis of said plug with respect to said socket member. The fastener body may have a projection disposed adjacent to the plug and receivable in an elongate groove formed in the socket member to extend arcuately about the axis of the stepped bore to a limited angular extent. The socket member may be attached to the fabric of the bag by means of a mounting plate disposed on the fabric opposite to the socket member. With the mounting plate thus provided, the fastener body undergoes smaller frictional resistance imposed by the mounting plate than by the fabric of the bag when the fastener body is angularly displaced with respect to the socket member. These and other objects and features of the invention will be better understood from the following detailed description taken in connection with the accompanying drawings, in which like reference numerals are taken to refer to like or corresponding parts throughout the several views. Figure 1 is an exploded cross-sectional view of a strap fastener embodying the present invention; Figure 2 is a front elevational view of a body of the strap fastener shown in Figure 1; Figure 3 is a right side view of Figure 2; Figure 4 is a rear view of Figure 2; Figure 5 is a side elevational view of a socket member constituting part of the strap fastener; Figure 6 is a front elevational view of the socket member; Figure 7 is a cross-sectional view taken along line XII - XII of Figure 6; Figure 8 is a front elevational view of a mounting plate constituting another part of the strap fastener; Figure 9 is a cross-sectional view taken along line IX - IX of Figure 8; Figures 10 and 11 are cross-sectional views illustrative of the operation of the strap fastener of Figure 1; Figure 12 is a front elevational view of a modified strap fastener according to the present invention; Figure 13 is a cross-sectional view taken along line XIII - XIII of Figure 12; Figure 14 is a rear view of Figure 12; Figure 15 is a front elevational view of another modified form of strap fastener; Figure 16 is a cross-sectional view taken along line XVI - XVI of Figure 15; Figure 17 is a rear view of Figure 15; and Figure 18 is a perspective view of a knapsack having straps secured in a manner known in the art. Referring now to the drawings and Figure 1 in particular, there is shown a strap fastener 10 which comprises a fastener body 11, a mounting plate 12 and a socket member 13 all molded of synthetic resin. The fastener body 11 includes a base plate 14 having a laterally outwardly extending lug 15 at one or its upper end, a pair of co-axial pins 16 at the other or its lower end, a laterally outwardly extending locking prong 17 intermediate between the lug 15 and the pin 16, and a laterally inwardly extending plug 18 opposite to the prong 17. A flange 19 having a slit 20 extends upwardly from the lug 15. The base plate 14 is provided adjacent to the lug 15 with a laterally elongated slot 21 so that the upper end portion of the base plate 14 posesses a certain degree of resiliency which is large enough to enable the lug 15 to tilt about its distal end upwardly away from the prong 17. The fastener body 11 further includes a cover plate 22 having a plurality of laterally elongated openings 23, 24, 25, 26 for the passage therethrough of a strap S, a pair of apertured lower flange portions 27 pivotally connected to the respective pins 16 of the base plate 14, and an upper flange portion 28 having a locking projection 29 engageable in complementarily shaped recess 30 formed in the lower surface of the lug 15. The first opening 23 is defined between the flanged portions 27 and a first cross bar 31; the second opening 24 between the first cross bar 31 and a second cross bar 32; the third opening 25 between the second cross bar 32 and a third cross bar 33; and the fourth opening 26 between the third cross bar 33 and the upper flange portion 28. The second cross bar 32 is slightly off-set from the common upper plane of the cover plate 22 so as to make the strap S lie substantially flush with the upper surface of the cover 22. The third cross bar 33 has a longitudinal locking ridge 33 a extending along its rear edge and projecting into the third opening 25. With the strap S passed through any of the openings 23 - 26, the cover plate 22 is rotated about the pins 16 in the direction of the arrow into coupling engagement with the base plate 14 as better shown in Figure 3 when the locking projection 29 is snapped into the recess 30 to hold the cover 22 and the plate 14 retentively together, while the locking prong 17 enters into the third opening 25 and holds the strap S immovably against the side wall of the third cross bar 33. In this instance, the locking ridge 33 a on the third cross bar 33 bites into the web of the strap S. The plug 18, which extends laterally centrally from the base plate 14 in opposition to the locking prong 17, has a hollow cylindrical configuration and includes a stem portion 18 a integral with the base plate 14 and an enlarged head portion 18 b separated by an interrupted annular shoulder 18 c from the stem portion 18 a . The hollow cylindrical plug 18 further includes a plurality (four in the illustrated embodiment) of longitudinal slits 18 d in a criss-cross formation, as better shwon in Figure 4, to render the plug 18 resilient and radially inwardly deformable. The head portion 18 b has a tapered end 18 e . The base plate 14 and the cover plate 22 may be conveniently, though not exclusively, fabricated by injection-molding in assembled condition. The mounting plate 12 to be interposed between the fastener body 11 and the socket member 13 is generally rectangular in shape and has a central aperture 12 a for receiving a portion of the socket member 13 and a plurality of laterally extending anchoring posts 12 b each with an axial blind hole 12c, there being four of these posts equally spaced around the central aperture 12 a as better shown in Figure 8. The socket member 13, which constitutes another part of the strap fastener 10, includes a substantially rectangular plate 13 a and a cylindrical neck 34 extending centrally from the base plate 13 a . The socket member 13 further has a stepped bore 35 extending through the base plate 13 a and the neck 34. The stepped bore 35 is composed of a small-diameter portion 35 a extending concentrically through the cylindrical neck 34, and a large-diameter portion 35 b extnding through the base plate 13 a . The large- and small-diameter portions 35 b , 35 a are separated by an annular step 37 which is lockingly engageable with the interrupted annular shoulder 18 c when the plug 18 is snapped in the stepped bore 35. The inside diameter of the small-diameter portion 35 a is substantially the same as, preferably slightly larger than, the outside diameter of the cylindrical stem 18 a of the plug 18. The outside diameter of the head 18 b of the plug 18 is larger than the inside diameter of the small-diameter portion 35 a and is smaller than the inside diameter of the larger-diameter portion 35 b . As shown in Figure 6, the socket 13 is provided with a plurality (four in number in this embodiment) of countersunk holes 38 at locations registering with the anchoring posts 12 b of the mounting plate 12. With this construction, the mounting plate 12 and the socket member 13 are first brought into coupling engagement with each other by inserting the neck 34 of the socket 13 into the central aperture 12 a of the mounting plate 12 through an opening in a substrate such as sheet of fabric or leather C of a knapsack, with the anchoring posts 12 b received in the corresponding holes 38. The lugs 12 b may be plastically deformed by press or with heat to swell out and anchor within the countersunk holes 38, thereby joining the mounting plate 12 and the socket member 13 with the fabric sheet C sandwiched therebetween, as better shown in Figure 10. The fastener body 11 is then taken into coupling engagement with the socket member 13, which has been united with the mounting plate 12, by inserting the plug 18 into the stepped bore 35. As the head 18 b of the plug 18 advances along the small-diameter portion 35 a of the stepped bore 35, the head 18 b is resiliently deformed radially inwardly. A further forward movement of the plug 18 causes the head 18 b to be snapped into the large-diameter portion 35 b due to the resiliency of the plug 18. In this instance, the interrupted annular shoulder 18 c is held in interlocking engagement with the step 37 to hold the fastener body 11 and the socket member 13 in coupled condition, as shown in Figure 11. The back of the fastener body 11 is held in contact with the face of the mounting plate 12. The fastener body 11 can be rotated at will in either direction about an axis of the plug 18 relative to the socket member 13 so as to adjust the lateral position of the strap S on the knapsack to suit the particular physical characteristics of the user. In this instance, the fastener body 11 undergoes smaller frictional resistance imposed by the mounting plate 12 than by the fabric C of the knapsack. The strap S can be also adjusted lengthwise by pulling its leading end in and out through the slot 21 in the base plate 14 of the fastener body 11, for which purpose and for removal or attachment of the strap S there may be used for example a screwdriver D (placed in the slit 20 in Figure 10 and then tilted in the direction of the arrow A) with which to unlock or release the locking projection 29 from the recess 30. Figures 12 through 14 show a modified form of strap fastener 40 which comprises a strap holder 41 pivotably connected at one end as at 42 to a base plate 43 and at the other end with a cross bar 44 around which is passed the strap S. The base plate 43 carrying a plug 45 identical in construction and function with the plug 18 of Figure 1. A socket member 46 of the strap fastener 40 is substantially the same as the socket member 13 of Figure 1 with the exception that an elongate groove 47 extends arcuately in the face of a neck 48 to a limited angular extent about the axis of a stepped bore 49. When the plug 45 is snapped in the stepped bore 49, the groove 47 loosely receives a projection 50 on the back of the base plate 43. With the groove 47 and the projection 50 thus provided, the fastener body 41 is rotatable only within the limited angular extent with respect to the socket member 46 and hence the fabric C of a bag. Figures 15 through 17 show another modified form of strap fastener 51 which comprises a fastener body or buckle 52 composed of a male part 53 and a female part 54 releasably engageable with each other. The male part 53 has at one end a cross bar 55 for mounting the strap S and at the other end a hook 56 releasably engageable with an abutment strip 57 formed on the female part 54. The female part 54 includes a plug 58 extending from the back thereof and a projection 59 disposed adjacent to the plug 58. The plug 58 is identical in construction and function with the plug 45 of Figure 13. When the plug 58 is snapped with a socket member 60, the projection 59 is received in an arcuately extending groove 61 in the face of a neck 62 of the of the socket member 60. The angular movement of the fastener body 52 relative to the socket member 60 is limited to a certain extent by engagement of the projection 59 with ends of the arcuate groove 61.

Claims: 1. A strap fastener (10; 40; 51) for connecting a strap (S) to the fabric (C) of a bag, comprising: a socket member (13; 46; 60) adapted to be mounted on the fabric (C) of the bag and having a stepped bore (35; 49); and a fastener body (11; 41,43; 52) having means (17,33; 44; 55) for retaining the strap (S), and a plug (18; 45; 58) projecting from the back of said fastener body (11; 41,43; 52), said plug (18; 45; 58) including an enlarged head (18b) snappingly fittable in said stepped bore (35; 49) in said socket member (13; 46; 60) to couple said fastener body (11; 41,43; 52) with said socket member (13; 46; 60), said fastener body (11; 41,43; 52) in coupled condition being rotatable about the axis of said plug (18; 45; 58) with respect to said socket member (13; 46; 60). 2. A strap fastener according to claim 1, said plug (18) being of a hollow cylinder including at least one longitudinal slit (18d), said hollow cylindrical plug (18) including a stem (18a) integral with said fastener body (11) and an interrupted annular shoulder (18c) separating said stem (18a) and said enlarged head (18b), said stepped bore (35) including a smaller-­ diameter portion (35a) of an inside diameter smaller than the outside diameter of said enlarged head (18b), and a larger-diameter portion (35b) of an inside diameter larger than the outside diameter of said enlarged head (18b), said smaller-and larger-diameter positions (35a, 35b) being separated by an annular step (37), said annular step (37) being slidingly engageable with said interrupted annular shoulder (18c). 3. A strap fastener according to claim 2, said stem (18a) having an outside diameter substantially the same as the inside diameter of said smaller-diameter portion (35a) of said stepped bore (35). 4. A strap fastener according to claim 1, 2 or 3, said fastener body (43; 52) including a projection (50; 59) disposed on the back thereof, said socket member (46; 60) having an elongate groove (47; 61) receptive of said projection (50; 59) and extending arcuately about the axis of said stepped bore (49) to a limited angular extent. 5. A strap fastener according to claim 1, further including a mounting plate (12) adapted to be disposed on the fabric (C) of the bag opposite to said socket member (13; 46; 60) for attaching said socket member (13; 46; 60) to the fabric (C), said mounting plate (12) having an aperture (12a) for the passage of said plug (18; 45; 58). 6. A strap fastener according to claim 5, said socket member (13) including a plate (13a) and a cylindrical neck (34; 48; 62) projecting from said plate (13a), said stepped bore (35; 49) extending coaxially through said neck (34; 48; 62), said neck 34; 48; 62) being fittedly receivable in said aperture (13a) in said mounting plate (12). 7. A strap fastener according to claim 5, said fastener body (43; 52) including a projection (50; 59) disposed on its back adjacent to said plug (45; 58), said neck (48; 62) having an elongate groove (47; 61) receptive of said projection (50; 59) and extending arcuately about the axis of said stepped bore (49) to a limited angular extent.

Inventors: KASAI, KAZUMI
Applicants: YOSHIDA KOGYO K.K.
Application year: 1987
Main classification: A45C13
IPC codes: A45C13, A44B11, A45F3, F16G11