Abstract:
A slider for a slide fastener is provided with an openable bridge suitable to remove or replace a pull tab, wherein a base of the bridge is connected to the slider body by a connection allowing a combination of linear displacement and pivoting relative to the slider body, a linear displacement of the bridge causes the lock/unlock of the bridge to/from a retaining member of the slider body, and a pivoting of the bridge causes the opening/closing of a front passage for removal or insertion of a pull tab. The bridge portion may also include a locking member associated with the bridge.

Description:
TECHNICAL FIELD 
       [0001]    The present invention refers to a slider for a slide fastener. More in detail, the invention relates to a slider with a bridge that can be shifted between a first position and a second position, for example to remove or replace a pull tab. 
       BACKGROUND OF RELATED ART 
       [0002]    A slide fastener basically comprises a pair of tapes bearing respective rows of teeth, top and bottom stops, and a slider with a pull tab. The slider basically comprises an upper blade, a lower blade, a central portion between the upper and lower blade, which is called diamond, and a bridge extending over the upper blade. The pull tab is inserted between the bridge and the upper blade and is held in position by the bridge. 
         [0003]    A technical problem encountered in the current technique of manufacturing slide fasteners is the need of a removable pull tab. 
         [0004]    A removable pull tab may be desired for example to avoid damage of the pull tab caused by the manufacturing process of the slide fastener, or of the item (e.g. suit, bag, etc.) comprising the slide fastener. For example, it may be desirable to protect an expensive metal puller from manufacturing steps such as sewing and finishing. Especially in the field of luxury goods, the pull tab may be a delicate and expensive item. It should also be considered that a damage of the pull tab is likely to be visible and disappointing for the customer. 
         [0005]    The above problem could be avoided by adding the pull tab at a final stage of the manufacturing process. However, it is often desirable to open and close the slide fastener during the process, which is much easier if the pull tab is mounted. In some embodiments of slide fasteners, the pull tab is indispensable to release a locking device and open the slide fastener. Another reason to provide a removable pull tab is customization of the slide fastener. 
         [0006]    A known solution is the use of a disposable plastic pull tab during the manufacturing process, which however has some disadvantages including the need of ab additional disposable pull tab and the step of cutting or breaking the plastic pull tab at the end of the process, for insertion of the true pull tab intended for the product. 
         [0007]    EP 2 322 050 discloses a process for making a slide fastener wherein a protective cap is applied on the front portion of a resilient member of the slider. The protective cap allows easy insertion of a puller and, where appropriate, releases a locking device of the slider, thus allowing the opening and closing of the slider without the puller. This system is satisfactory but still has the drawback of requiring an additional item, that is the protective cap. 
         [0008]    Other prior art solutions of sliders with interchangeable pull tab involve a complicated design of the slider body, including for example a slidable pull tab carrier, see e.g. EP 1 987 730. 
       SUMMARY 
       [0009]    The purpose of the invention is to avoid the above drawbacks of the prior art. The aims of the invention include the provision of a simple and cost-effective slider with a removable and interchangeable pull tab, as well as a releasable locking system. 
         [0010]    The aims are reached with a slider for a slide fastener according to the independent claim  1 . Preferred features are stated in the dependent claims. 
         [0011]    The slider body includes a diamond, an upper blade, a lower blade and a bridge. Said bridge is connected to the slider body by connection means allowing a combination of linear displacement and pivoting relative to the slider body between two end positions. Said two positions include: i) a first position wherein the bridge is engaged with a retaining member of the slider body, and ii) a second position wherein the bridge is disengaged from said retaining member and is rotated relative to the slider body. 
         [0012]    The first position can be termed “closed” and the second position can be termed “open”. The bridge in the second position may define a front passage suitable for insertion or removal of a pull tab. Said passage is closed when the slider is in the first position, thus holding the pull tab in place. 
         [0013]    Said linear displacement is preferably in a longitudinal direction of the slider. Said term of longitudinal direction denotes a direction which is parallel to the sliding direction of the slider. In some embodiments, it is substantially parallel to the upper and lower blades. 
         [0014]    Preferably, the bridge is connected to the slider body via a rotation pin inserted in at least one slot. Hence, the rotation pin provides the pivoting feature while the slot provides the linear displacement feature. In a preferred embodiment a rotation pin is fixed to the slider body and the bridge comprises one or more slot to engage said pin. A preferred embodiment has a fixed pin and sliding slot(s); alternative embodiments may be realized with a sliding pin. 
         [0015]    Preferably, the slider comprises elastic means disposed to urge the bridge in the first position. More preferably, said elastic means are configured to oppose the linear displacement of the bridge relative to the slider body. In a preferred embodiment, said elastic means are housed in the bridge. The elastic means may be for example a coil spring. Preferably the elastic means are energized (for example a spring is slightly compressed) when the bridge is in the first position. 
         [0016]    In some embodiments of the invention, the slider comprises also locking member to prevent undesired sliding. 
         [0017]    The locking member, for example, may be configured to protrude through an opening of the upper blade, in such a way that when the slider is fitted on a slide fastener, the locking member is able to engage the teeth in the region between the upper and lower blades, thus locking the slider itself. 
         [0018]    One of the preferred aspects of the invention is the integration between the bridge and the locking member. Preferably, the locking member is engaged when the bridge is in the first position, and is released when the bridge is in the second position. 
         [0019]    In a particularly preferred embodiment, said locking member is associated to the bridge, for example it is at least partially inserted in a recess of the bridge. Both the locking member and the bridge are pivotable together around a pin; the locking member however has only the degree of freedom of pivoting around said pin, while the bridge is also longitudinally slidable relative to said pin. More preferably, said elastic means act between the bridge and the locking member. 
         [0020]    In a preferred embodiment, the locking member comprises a cam which copies a profile of the bridge, suitable to provide at least a partial disengagement of the locking member upon displacement of the bridge. 
         [0021]    A pull-tab can be easily removed or replaced by opening and closing the bridge. Hence, for example, a temporary pull-tab can be inserted whenever necessary during the manufacturing process of the slide fastener, or of an item comprising the same. Then the temporary pull tab can be removed and a final pull tab inserted. Opening the bridge portion of the slider is easy but, at the same time, the closure is safe and reliable thanks to the combined pivoting and displacement. 
         [0022]    Another advantage is the simple construction of the slider body. The invention eliminates the need of expensive design of the slider body, including moving parts such as slidable pull tab carrier and/or elastic members mounted directly in the slider body. 
         [0023]    The bridge in the open position can be used as a puller, which means that the slide fastener can be operated (e.g. during the manufacturing of an item) even without a pull tab. 
         [0024]    Another advantage of the invention is the full integration with a locking system when provided. Since the locking member is associated with the bridge, the locking of the slider is automatically released by opening the bridge, even without a pull tab. 
         [0025]    These and further advantages of the invention will be more evident from the detailed description provided here below, given as indicative and not limiting example. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a side view of a slider according to an embodiment of the invention, in a first closed/locked position. 
           [0027]      FIG. 2  is a cross section of the slider of  FIG. 1 , according to a median vertical plane. 
           [0028]      FIG. 3  is a side view of the slider of  FIG. 1  with the bridge in an intermediate unlocked position. 
           [0029]      FIG. 4  is a cross section of the slider in the position of  FIG. 3  according to a median vertical plane. 
           [0030]      FIG. 5  is another cross section of the slider of  FIG. 3 , according to a vertical plane passing through one of the slots of the bridge. 
           [0031]      FIG. 6  is a side view of the slider of  FIG. 1  with the bridge in a second and open position. 
           [0032]      FIG. 7  is a cross section of the slider of  FIG. 6  according to a median vertical plane. 
           [0033]      FIG. 8  is an exploded view of the slider of  FIGS. 1 to 7 . 
           [0034]      FIG. 9  shows the insertion or removal of a pull tab to/from a slider according to the invention. 
           [0035]      FIGS. 10 and 11  are sectional views of a slider according to another embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    The figures show a slider  1  for a slide fastener, which basically includes a slider body  10  with a diamond  11 , an upper blade  12 , a lower blade  13  and a bridge  14 . 
         [0037]    The bridge  14  is shiftable between a first position of  FIG. 1 , and a second position of  FIG. 6 . 
         [0038]    The second position of  FIG. 6  is also termed open position, since the rotated bridge  14  defines a front passage  33 , which is suitable for insertion or removal of a pull tab  40  (see also  FIG. 9 ). 
         [0039]    The first position of  FIG. 1  is also termed closed position, since the front passage  33  is closed and a pull tab can be held in place between the bridge  14  and the upper blade  12 . 
         [0040]    In the first position, the bridge  14  is engaged with a retaining member  19  of the slider body  10  ( FIG. 2 ). A spring  24  housed in a seat  30  of the bridge  14  serves to normally keep the bridge  14  in the first closed/locked position. 
         [0041]    The bridge  14  can pass from the first position of  FIG. 1  to the second position of  FIG. 6  by a linear displacement followed by a rotation around a pin  17 . The linear displacement ( FIGS. 3 to 5 ) disengages the bridge  14  from the retaining member  19 ; the rotation around the pin  17  ( FIGS. 6 ,  7 ) opens the front passage  33 . 
         [0042]    Referring more in detail to the embodiments of the figures, the bridge  14  comprises a base  15  and a distal end  16  opposite to said base  15 . The rotation pin  17  is fixed to the slider body  10  and is received in a pair of slots  18  of said base  15 . 
         [0043]    The slots  18  are formed on lower projections  31  of the base  15 . Said slots are denoted by the slotted line of  FIG. 1 ; one of the slots is visible in the cross section of  FIG. 5  and the two slots are also visible in the exploded view of  FIG. 8 . The connection via pin  17  and slots  18  gives the bridge  14  the ability to linearly slide from the position of  FIG. 1  to the position of  FIG. 3 , and to rotate to reach the open position of  FIG. 6 . 
         [0044]    The distal end  16  is suitably configured to engage and disengage the retaining member  19  upon a linear shift of the bridge  14 . For example the front of the distal end  16  has a suitable recess  20  for engagement with a projecting tooth  21  of said retaining member  19 . The retaining member  19  is integral with the slider body  10  ( FIG. 2 ). 
         [0045]    The embodiments of the figures also comprise a locking member  22 . According to a preferred embodiment, said locking member is fitted in the bridge  14 . 
         [0046]    Said locking member  22  has a protrusion  23  adapted to engage the teeth of a sliding fastener (not shown) operated by the slider  1 , to prevent undesired opening of the slide fastener. 
         [0047]    In the first position of  FIGS. 1 and 2 , the protrusion  23  of the locking member  22  inserts into a passage  32  of the upper blade  12 , thus reaching the teeth in the region between the two blades  12 ,  13 . By abutting against the teeth, said protrusion  23  locks the slide fastener. Hence the position of  FIG. 1  is also a locked position of the slider  1 . On the other hand, the second position of  FIGS. 6 and 7  has the locking member  22  raised together with the bridge  14 , which means that the lock is released and the slider  1  is free. 
         [0048]    It should be appreciated that the locking member  22  can pivot together with the bridge  14  around the same pin  17 . However, the locking member  22  can only rotate around the pin  17 , while the bridge portion  14  has also the additional degree of freedom of a certain linear translation, thanks to the slots  18 . 
         [0049]    The assembly of bridge  14  and locking member  22 , in accordance with the shown embodiment, can be fully appreciated looking at  FIG. 8 . 
         [0050]    The pin  17  is inserted through and supported by projections  25  of the upper blade  12  of slider body  10 . The locking member  22  is partially received in a seat  26  of the bridge portion  14 , in such a way that a hole  27  of said locking member is aligned to holes  18  of said projections  25  and faces the slots  18 . Hence, the pin  17  is inserted through the holes  28  of said projections  25 , the hole  27  of the locking member  22 , and the slots  18  of the bridge  14 . 
         [0051]    The hole  27  of the locking member  22  has substantially the same diameter of the pin  17 , while the slots  18  are larger than said pin  17  in a direction of sliding of the bridge  14 , which is the longitudinal direction in the figures as denoted by d in  FIG. 3 . 
         [0052]    The coil spring  24  abuts against the bottom of the seat  30  and against a surface  29  of the locking member  22 . 
         [0053]    As already mentioned above, the locking member  22  has only one degree of freedom and can only pivot around the pin  17 , while the bridge  14  is also allowed to longitudinally slide by the displacement of the pin  17  in the slots  18 . 
         [0054]    Due to the elastic force of spring  24 , the bridge  14  and the locking member  22  can rotate together around the pin  17 , during the opening of the bridge  14 , as if they were a rigid body. However, the bridge  14  can also slide in a linear fashion, relative to the locking member  22  and slider body  10 , compressing or releasing the spring  24 . 
         [0055]    The locking member  22  comprises also a cam  34 , on the opposite part of the locking protrusion  23  relative to the pin hole  27 . Said cam  34  engages a respective profile  35  made in the base  15  of the bridge  14 . 
         [0056]    Another embodiment is illustrated by  FIG. 10  (released) and  FIG. 11  (locked). In this embodiment, a different accommodation of the coil spring  24  is provided. Instead of the seat  30 , the locking member  22  has a step  37  forming a plane surface substantially parallel to the opposite surface of the bridge  14 . Hence, the coil spring  24  can be received between the locking member  22  and bridge  14  without the need of making a deep hole in the bridge  14 . This embodiment may be preferred to ensure even better and smooth operation of the coil spring. Another advantage of this embodiment is that the bridge  14 , in particular the base  15 , is simpler to manufacture. 
         [0057]    The slider  1  operates in the following manner. 
         [0058]    In the closed/locked position of  FIGS. 1-2 , the coil spring  24  is slightly compressed. Due to its position and inclination, the spring  24  keeps the bridge  14  in the closed position, by urging the distal end  16  against the retaining member  19  ( FIG. 2 ). At the same time, the spring  24  tends to rotate clockwise the locking member  22  around the pin  17 , so that the locking member  22  is also urged in its locked position, against a step  36  of the slider body  10 , as shown in  FIG. 2 . The protrusion  23  is fully extended in the passage  32 , for engagement with the teeth of the fastener. 
         [0059]    The locking member  22  can be released by a pull tab during the normal use, lifting the middle of the locking member around the pin  17  until the teeth are freed from the protrusion  23 . The bridge  14  in this case will remain in its closed position, due to the engagement of front recess  20  and retainer  19 , which is unaffected by the action on the pull tab. 
         [0060]      FIG. 3  shows how to open the bridge  14 . The bridge  14  is first pushed as denoted by d, relative to the slider body  10  and locking member  22 , against the spring  24  which is further compressed. By doing so, the distal end  16  is progressively disengaged from the retaining member  19  as seen in the sectional view of  FIG. 4 . 
         [0061]    The pin  17  slides from one end to another end of the slots  18 , that is from left end to the right end in the figures. In the meantime, the locking member  22  is rotated around the pin  17  by the cam  34  copying the profile  35 , thus starting to disengage the lock. 
         [0062]    When fully released from the retaining member  19 , the assembly of bridge  14  and locking member  22  (hold together by the action of the spring  24 ) is free to pivot around the pin  17 , reaching the open position of  FIGS. 6 and 7 . 
         [0063]    The rotation of the bridge  14  opens the front passage  33  which allows insertion or removal of a pull tab. The locking member  22  is released as well, pivoting together with the bridge  14  and bringing the protrusion  23  away from the locking position in the passage  32 . 
         [0064]    The skilled person will realize that inserting or replacing the pull tab is quite easy, as shown by  FIG. 9 . Further to this, the same bridge  14 , when in the open position of  FIG. 6 , could be used to manually open or close the slide fastener. In other words, when the bridge  14  is opened and the locking member  22  is also released, the bridge itself can be used as a sort of puller. This feature may be useful during a manufacturing process of the slide fastener or of an item comprising the same, because the slide fastener can be opened or closed even without a pull tab. 
         [0065]    The closing of the bridge is as follows. Starting from the open position of  FIG. 6 , the bridge  14  is lowered until it is substantially horizontal, then it is shifted back to the position of  FIG. 1 , slightly compressing the spring  24 . When the position of  FIG. 1  is reached, the system is stable thanks to the spring  24  urging the end  16  against the retainer  19  and the locking member  22  against the step  36  of the body  10 . 
         [0066]    The figures show also the advantage of a simple construction, especially of the slider body. The slider body  10  has no moving parts and the spring  24  is fully received in the slider bridge  14 . No hole or seat for a spring is to be provided in the body  10 . Another advantage is that a single elastic element, such as the spring  24 , keeps both the bridge  14  and the locking member  22  in the closed/locked position. The invention combines the functionality of an openable bridge, removable pull tab and releasable locking system, in an efficient and cost-effective manner.