Patent Publication Number: US-8984723-B2

Title: Adjustable strap assembly, slider and connector

Description:
This application is related to and claims priority from International Application Number PCT/GB2010/051726, filed Oct. 13, 2010, titled “Adjustable Strap Assembly, Slider and Connector,” published Apr. 28, 2011 as WO 2011/048406 A1, and which designated the United States, and which claims priority from GB 0918433.4, filed Oct. 21, 2009. The entire contents of International Application Number PCT/GB2010/051726 which are hereby fully incorporated herein by reference for all purposes. 
     The present invention relates to an adjustable strap assembly, particularly but not exclusively for use in clothing, and to a slider and a connector for use in an adjustable strap assembly. 
     It is known to provide adjustable strap assemblies that include a slider, for example for shoulder straps of a garment. Typically one end of the strap is connected to the slider, and the strap passes through a ring that is attached to one part of the garment, then through the slider, and is then attached to another portion of the garment. Movement of the slider along the strap adjusts the effective length of the strap. The slider may for example consist of a frame with a central bar and a pair of parallel slots or gaps, one on either side of the bar. The end of the strap may be fixed onto the central bar, while the adjustable portion of the strap passes through one slot, over the central bar, and then through the other slot. The attachment of the end of the strap to the central bar may be by looping around the bar and stitching the free end of the strap to the adjacent portion of the strap. The end of the strap may instead be welded onto the central bar, as described for example in U.S. Pat. No. 7,140,080. Alternatively the end of the strap may be attached to a projecting flange at one end of the slider, as described in U.S. Pat. No. 6,056,626. 
     Such adjustable strap assemblies are used in undergarments, for example in a brassiere worn under a blouse. However they tend to produce a bulge in the over garment (such as the blouse) at the positions of the slider and the attachment ring, which may be unsightly. An object of the present invention is to provide an adjustable strap assembly that is less noticeable, because the assembly is slimmer and produces less of a bulge. 
     According to the present invention there is provided an adjustable strap assembly comprising a strap, a slider, and an end connector which may be connected to a garment, wherein an end of the strap is attached to the slider, and the strap passes through the end connector and through the slider, wherein the end connector comprises a bar around which the strap passes, and comprises an outer plate such that the portions of the strap on either side of the bar both pass below the outer plate at a front end of the connector. 
     The end connector is itself attached, directly or indirectly, to the garment. For example a short length of connecting strap may be attached, for example by welding, onto the end connector at the end opposite the front end, the other end of the connecting strap being sewn onto the garment. In a preferred embodiment the end connector also comprises a front guide element spaced apart from the front end of the outer plate so as to define a slot, and the two portions of the strap pass through this slot. The bar within the end connector may be of rounded cross-section, but it preferably has at least one edge or corner around which the strap passes, for example being of square or rectangular cross-section. Such an edge or corner enhances the friction within the end connector. Since the two portions of the strap both pass under the outer plate, they are held flat and on top of each other, so the end connector is comparatively slim. Since the adjustable strap assembly of the invention is slimmer, it produces less of a bulge; also, being slimmer, the assembly is more comfortable to wear, which provides another advantage. Furthermore, the friction where the strap passes through the end connector may be greater than or similar to the friction where the strap passes through the slider. 
     The slider comprises a frame and a crossbar, one end of the strap being connected to the slider, and the strap passing through the end connector and then through the slider, the strap passing around the crossbar. The strap may be said to pass under the ends of the frame and over the crossbar—the face of the slider that faces those portions of the strap may be referred to as the lower surface of the slider, while the opposite face of the slider may be referred to as its outer surface. The end of the slider closest to the end connector may be referred to as the rear end of the slider, and the end furthest from the end connector may be referred to as the front end of the slider. 
     Preferably the slider tapers towards both ends, and the crossbar is attached to the frame such that a portion of the strap passing over the crossbar does not protrude above the outer surface of the slider. Preferably the outer surface of the frame is curved in longitudinal profile. These features ensure that there are no abrupt changes in thickness of the strap assembly. 
     Preferably the crossbar is of wedge-shaped or triangular cross-section. Preferably it has a sloping front face (the face nearer the front end of the slider). The rear face (the face nearer the rear end of the slider) is preferably more steeply sloped, and may be substantially orthogonal to a longitudinal axis of the slider. Desirably the front face and the rear face of the crossbar meet at an edge at the outer surface of the crossbar. Hence the strap passing over the crossbar undergoes an abrupt change of direction at this edge; this enhances friction between the strap and the slider. 
     Preferably part of the lower surface of a front portion of the frame slopes, so that in use the strap extends in contact with or close to the lower surface of the front portion of the frame over at least part of its length. This ensures a smooth transition between the strap outside the slider and the sloping portion of strap leading up to the crossbar. Indeed a part of the lower surface of the front portion may be substantially parallel to the sloping front face of the crossbar. And preferably the lower surface of the frame is curved in longitudinal profile, so that the ends of the frame are above the lowermost portion of the slider. This ensures that the strap emerging from the end of the slider does not increase the overall thickness of the assembly. 
     Preferably the lower surface of the rear portion of the frame also slopes, so that the strap extends in contact with at least part of the lower surface of the rear portion. And preferably the attached end of the strap is attached to the underside of the slider at the rear edge of the slider; the slider preferably defines a flange to locate an end of the strap, the end of the strap being fixed to the flange. This may be by ultrasonic welding. 
     The outer surface of the frame may form a continuous surface between the front and the back of the slider; this helps ensure a smooth profile to the assembly. Alternatively the outer surface may define an aperture; this makes it easier to feed the strap through the slider. It is desirable if the aperture does not extend the full width of the crossbar, so that in use at least the edges of the strap that pass over the crossbar are hidden, but alternatively the aperture may have a width substantially equal to that of the crossbar. Particularly where the aperture does not extend the full width of the crossbar, the aperture may have a decorative appearance. 
     In a second aspect the invention provides a slider for use in an adjustable strap assembly; and in a third aspect provides an end connection for use in an adjustable strap assembly. It will be appreciated that the slider of the invention may be used in conjunction with an end connector that does not conform to the present invention; and it will be appreciated that the end connector of the invention may be used in conjunction with a slider that does not conform to the present invention. 
    
    
     
       The invention will now be further and more particularly described, by way of example only, and with reference to the accompanying drawings in which: 
         FIG. 1  shows a side elevation of an adjustable strap assembly of the invention; 
         FIG. 2  shows a perspective view showing the underside of the end connector of the assembly of  FIG. 1 ; 
         FIG. 3  shows a longitudinal sectional view of the end connector of  FIG. 2 ; 
         FIG. 4  shows a perspective view showing the underside of the slider of the assembly of  FIG. 1 ; 
         FIG. 5  shows a side view of the slider of  FIG. 4 ; 
         FIG. 6  shows a longitudinal sectional view of the slider of  FIG. 4 ; 
         FIG. 7  shows a longitudinal sectional view of a modification to the slider of  FIG. 4 ; 
         FIG. 8  shows a longitudinal section of a perspective view of an alternative end connector for use in the adjustable strap assembly of  FIG. 1 ; and 
         FIG. 9  shows a modification of the end connector of  FIG. 8 . 
         FIG. 10  shows a perspective view showing the underside of an end connector; 
         FIG. 11  shows a longitudinal sectional view of the end connector of  FIG. 10 ; 
         FIG. 12  shows a longitudinal section of a perspective view of an alternative end connector; and 
         FIG. 13  shows a modification of the end connector of  FIG. 12 . 
     
    
    
     Referring now to  FIG. 1  there is shown an adjustable strap assembly  10  that may be used in a brassiere to provide a shoulder strap. The assembly  10  consists of a strap  12 , a slider  14 , and an end connector  16  for connection to the garment (not shown), such as the brassiere. The slider  14  and the end connector  16  are of a plastics material, such as nylon, and can be formed by moulding. One end  12   a  of the strap  12  is attached to the slider  14 , and the strap  12  passes through the end connector  16  and through the slider  14 . The other end of the strap (not shown) is connected to the garment at another position. The end connector  16  is connected to a short length of connecting strap  18 , and the other end of the connecting strap  18  is sewn into the garment. If the strap assembly  10  forms a shoulder strap, then typically the end connector  16  would be attached either directly, or by means of a connecting strap  18 , to a position at the front of the garment, and the other end of the strap would be connected to a position at the back of the garment. To adjust the length of the strap assembly  10  the slider  14  would be moved along the strap  12 , and the strap  12  would also be eased through the end connector  16  to ensure that the two portions of strap  12  between the slider  12  and the end connector  16  remain of equal length. There is sufficient friction between the slider  14  and the strap  12 , and also between the end connector  16  and the strap  12 , that the strap assembly  10  remains at the length set by the user; but the friction is not so great as to prevent the user from adjusting the length. 
     Referring now to  FIG. 2 , the end connector  16  consists of an outer plate  20  from which project sidewalls  22 . The lowermost parts of the sidewalls are linked by a crossbar  24  and by a front guide plate  23 , so that there is a generally rectangular slot  25  at the front of the end connector  16  defined between the outer plate  20  and the front guide plate  23 . By way of example the total thickness of the end connector  16  may be less than 5 mm, for example less than 4 mm, and in one example is 3.5 mm. As shown in  FIG. 3 , in which the line followed by the strap  12  is shown by a broken line, the strap  12  extends through the slot  25 , passes around the crossbar  24 , and extends back through the slot  25 . Thus the portions of the strap  12  on either side of the crossbar  24  both pass through the slot  25 . 
     The underside of the outer plate  20  at the opposite end from the slot  25  defines a flange  26  whose front edge is delimited by a rim  27 , and on which are three conical projections  28 . The connecting strap  18  is placed on this flange  26  with its end up against the rim  27 , and is subjected to ultrasonic welding. This causes the conical projections  28  to melt and the molten material becomes embedded in the strap  18 , so the strap  18  is securely fixed to the end connector  16 . It will thus be appreciated that in the finished product (as in  FIG. 1 ) the conical projections  28  no longer exist. 
     In use of the end connector  16  there is friction particularly where the strap  12  passes around three corners of the crossbar  24 , and around the rear corner of the front guide plate  26 ; there is also friction between the two straps  12  where they pass through the slot  25 . It will also be appreciated that the slot  25  ensures that the two parts of the strap  12  are flat and lie on top of each other. 
     Referring now to  FIG. 4 , the slider  14  consists of an outer plate  30  which (as shown particularly in  FIG. 1 ) defines a heart-shaped aperture  31 . Along each side are sidewalls  32  which are linked by a crossbar  34  about halfway along the slider  14 . Referring also to the side view of  FIG. 5  the sidewalls  32  are of greatest height around the midpoint of the slider  14 , and decrease in height towards both ends, the shape of the outer plate  30  and the sidewalls  32  being such that both the outer surface and the lower surface are curved from a thick region around the midpoint of the slider  14  to thinner regions at both ends. By way of example the slider  14  may be of thickness, at its maximum point, less than 5 mm, more preferably less than 4 mm, and in one example is about 2.8 mm thick. 
     Referring also to  FIG. 6 , the crossbar  34  is of wedge-shaped cross-section, with a gentle slope on its front face, whereas its rear face is perpendicular to the longitudinal axis of the slider  14 . In this example the front face is inclined at about 25° to the longitudinal axis, although it will be appreciated that the front face might be inclined at a different angle, although preferably between 20° and 35°. The underside of the crossbar  34  is at the lowermost part of the slider  14  such that if the slider  14  rests on a surface parallel to its longitudinal axis, there is a gap between the surface and the underside of the outer plate  30  at both ends of the slider  14 , and the strap  12  can therefore pass through these gaps (its path being shown by the broken line). The under surface of the outer plate  30  has a portion  36  parallel to the longitudinal axis at the front of the slider  14 ; it then has a portion  37  that slopes upwardly, approximately parallel to the front face of the crossbar  34 , and then curves over the top corner of the crossbar  34  and slopes downwardly towards the rear of the slider  14 . There is then a portion  38  parallel to the longitudinal axis. The rear-most portion of the outer plate  30  defines, on its underside, a flange surface  40  parallel to the longitudinal axis, terminating in a step  41  leading to the portion  38 , and on the flange surface  40  are a number of conical projections  42 . 
     The portion of the strap  12  that is to be attached to the slider  14  is placed on the flange surface  40  with the end of the strap  12  up against the step  41 , and is subjected to ultrasonic welding. As described above this causes the conical projections  42  to melt and the molten material becomes embedded in the strap  12 , so the end of the strap  12  is securely fixed to the underside of the rear end of the slider  14 . It will be appreciated that in the assembled product the conical projections  42  no longer exist. 
     In use of the slider  14  the strap  12  follows the broken line, passing under the flat portions  36  and  38  at the front and towards the rear of the slider  14 , respectively; and passing over the crossbar  34 . There is consequently friction between the strap  12  and the corner along the top edge of the crossbar  34 , where the strap  12  has to undergo an abrupt change of direction. The friction in the slider  14  in combination with the friction between the strap  12  and the end connector  16  together ensure that the strap assembly  10  remains at the length set by the user. Nevertheless the user is not prevented from adjusting the length of the strap. 
     It will be appreciated that the strap assembly  10  described above, and in particular the slider  14  and the end connector  16 , are by way of example only, and that they may be modified in various ways while remaining within the scope of the present invention. By way of example, referring now to  FIG. 7 , there is shown a slider  44  which differs from the slider  14  in that there is no aperture  31 , so that the outer plate  45  provides a continuous and smooth outer surface. As in the slider  14 , the crossbar  34  is of wedge-shaped cross-section, and is at the lowermost part of the slider  44 ; and the under surface of the outer plate  45  has the same shape as that of the outer plate  30 , defining a continuous smooth curve from a region in front of the crossbar  34  to a region behind it. Again there is a flange surface  40  terminating in a step  41 , onto which the end of the strap  12  may be welded; this surface  40  may be provided with conical projections  42  (not shown in  FIG. 7 ). 
     Referring now to  FIG. 8  there is shown an alternative end connector  50  in which the connecting strap  18  (or the garment) may be attached to the outer face of the end connector. The end connector  50  consists of an outer plate  51  from which project sidewalls  52 , linked together at their lower edge by a crossbar  54  and by a front guide plate  53 , so that there is a generally rectangular slot  55  at the front of the end connector  50  defined between the outer plate  51  and the front guide plate  53 . The sidewalls  52  project rearwardly beyond the outer plate  51 , and at the rear of the connector  50  they are joined by a rear flange  56 , on whose upper surface are a number of conical projections  58 . The upper surface of the rear flange  56  is lower than the underside of the outer plate  51 , the gap between them being approximately equivalent to the thickness of the connecting strap  18 , so that the strap  18  can be placed on the rear flange  56  with its end locating under the rear edge of the outer plate  51  up against a lip  57  that projects from the lower surface of the outer plate  51 . 
     The strap  18  is then welded onto the rear flange  56  as described above, so that the conical projections  58  no longer exist in the final product. The end of the strap  18  is not exposed, because it is concealed by the rear edge of the outer plate  51 . The strap  12  is fed through the end connector  50  in the same way as described above, passing through the slot  55 , around the crossbar  54 , and back out through the slot  55 , as indicated by the broken line. 
     Referring now to  FIG. 9  there is shown an alternative end connector  60 , which has many features in common with the end connector  50 . It differs in that the crossbar  64  is closer to the outer plate  51 , and so higher relative to the under surface of the front guide plate  53 . This reduces the change of direction of the portion of the strap  12  that extends from the slot  55  to the underside of the crossbar  64 . It also reduces the extent to which the strap  12  that passes below the crossbar  64  projects lower than the lower surface of the front guide plate  53 . It will be appreciated that this modification—raising of the crossbar relative to the under surface of the connector—would be equally applicable to the end connector  16  of  FIG. 2 . 
     In a further modification to the end connector  16 ,  50  or  60 , the front guide plate  23  or  53  may be omitted. Since the under surface of the end connector, in use, lies against the body or against another garment, the two portions of the strap  12  emerging from the front of the end connector would in any event be constrained to pass through a slot defined between the front edge of the outer plate  20  or  51  and the underlying body or garment. This modification would provide less friction than the previously-described end-connectors  16 ,  50  or  60 . 
     In another alternative, the slider might also be arranged to have the strap  12  attached at a different position, for example to the outer surface. And indeed in both the slider and the end connector the strap  12  or  18  might instead be located in a slot defined in the outer plate, and welded into position. As regards the end connectors  16 ,  50  and  60  in each case the crossbar  24 ,  54 ,  64  is of generally rectangular cross-section (with a wider end portion where it joins onto the sidewalls  22 ,  52 ), but the crossbar might instead have a different cross-sectional shape, for example having the front corner rounded so that the bulk of the friction is only at the rear two corners, or indeed having two of the corners rounded, or even having all the corners rounded, so that the crossbar might be oval or circular in cross-section, the friction in this case being provided by the contact between the two parts of the strap  12  as they pass through the slot  25 ,  55 . Similarly the front guide plate  23 ,  53  might have a different shape to that shown, for example being somewhat longer, or having a rounded corner around which the strap  12  passes.