Patent Publication Number: US-2017361553-A1

Title: Sipe blade  venting structure

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to venting structures for tire molds. More particularly, the present disclosure relates to a venting structure for a sipe blade region of a tire mold. 
     BACKGROUND 
     Tire molds include vent structures that allow the air in a tire mold to be displaced when rubber is compressed or injected into the mold. Sipe blades are sometimes included in a tire mold to create patterns in the finished tire. When the rubber is injected into the mold, the rubber will form around a sipe blade to create a void in the cured tire matching the shape of the sipe in a finished tire. In prior art structures, sipe blades include holes within the blade to allow air to vent from one side of the sipe blade to the other. The size of the holes, the number of the holes and the location of the holes is an exacting process and due to sipe size, material constraints and sipe placement during mold preparation, can be limiting. This results in less than optimal air flow. These structures degrade the appearance of a finished tire, as sprues may form on either side of the sipe blade, and break when the tire is removed from the mold. This can also result in tire “lightness,” where rubber does not completely fill in the voids of the tire mold and sipe junctions. 
     SUMMARY 
     In one embodiment, a tire mold has an interior surface and an exterior surface with a conduit connecting the two surfaces in a fluid connection. This embodiment further includes at least one sipe blade extending across an interior opening of the conduit, into an interior of the tire mold. This embodiment further includes a vent insert located within the at least one conduit. 
     In another embodiment, a system for venting a tire mold includes a tire mold with interior and exterior regions in fluid connection with each other via at least one conduit extending from the exterior region to the interior region. This embodiment further includes at least one sipe blade located in the interior region of the tire mold, that extends across the at least one conduit. 
     In another embodiment, a tire mold has an interior region and an exterior region with a conduit connecting the two in a fluid connection. This embodiment further includes at least one sipe blade positioned at an interior opening of the conduit, and extending into the interior region of the tire mold. The sipe blade in this embodiment is embedded into the tire mold. This embodiment further includes a vent insert located within the at least one conduit, and positioned between the sipe blade and the exterior region of the tire mold. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In the accompanying drawings, structures are illustrated that, together with the detailed description provided below, describe exemplary embodiments of the claimed invention. Like elements are identified with the same reference numerals. It should be understood that elements shown as a single component may be replaced with multiple components, and elements shown as multiple components may be replaced with a single component. The drawings are not to scale and the proportion of certain elements may be exaggerated for the purpose of illustration. 
         FIG. 1  is a front view of one embodiment of a notched sipe blade and a vent insert in a tire mold shown in cross section; 
         FIG. 2  is a front view of an exemplary vent insert in a tire mold shown in cross section; 
         FIG. 3  is a front view of an alternative embodiment of a sipe blade and a notched vent insert in a tire mold shown in cross section; 
         FIG. 4  is a side view of an exemplary notched vent insert; 
         FIG. 5  is a front view of another alternative embodiment of a notched sipe blade in a notched vent insert in a tire mold shown in cross section; 
         FIG. 6A  is a top view of one embodiment of a sipe blade bisecting a single conduit; and 
         FIG. 6B  is a top view of an alternative embodiment of a sipe blade with three segments and two conduits for venting. 
     
    
    
     DETAILED DESCRIPTION 
     The following includes definitions of selected terms employed herein. The definitions include various examples or forms of components that fall within the scope of a term and that may be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of terms may be within the definitions. 
     Directions are stated herein with reference to the tire mold. For example “interior,” “inside,” or “inner” refers to a direction or area towards the center cavity of a tire mold. The terms “exterior,” “outside,” or “outer” refer to a direction or area generally outside of the tire mold. 
       FIG. 1  illustrates a cross-section view of a first embodiment of the sipe venting structure. A tire mold  100  includes an interior surface  105  for receiving material used in manufacturing tires. The interior surface  105  may take any shape suitable for forming tires. The tire mold  100  further comprises a conduit  110  for venting air from the interior of the tire mold  100  to an exterior (not shown) of the tire mold  100 . The conduit  110  may take any form, but here is depicted as a cylindrical through hole, with an opening  115  in the interior surface  105 . The opening  115  permits fluid communication between the interior of the tire mold  100  and the exterior of the tire mold  100  via the conduit  110 . Other venting structures known in the art may be used without departing from the scope of the present disclosure. 
     A sipe blade  120  is secured in an opening in the tire mold  100 , such that a bottom of the sipe blade  120  is embedded within the tire mold  100 . Any means of securing the sipe blade  120  to the tire mold  100  may be used without departing from the scope of the present disclosure, including but not limited to forming the tire mold with the sipe blade, permanently mounting sipe blade after forming the tire mold, or affixing sipe blade to tire mold in a removable manner. 
     In this embodiment, the sipe blade  120  is depicted as having a flat rectangular top, having side portions  130  being shorter than the flat rectangular top, extending further than the flat rectangular top in a lengthwise direction, and having rounded outer portions. A bottom edge of the sipe blade  120  is substantially straight, with a notch  125  located in a central region of the bottom edge. The notch  125  is sized such that it is coextensive with the opening  115  in the interior surface  105 . Other shapes are possible for the sipe blade  120 , and may be substituted without departing from the scope of the present disclosure. 
     In this embodiment, the notch  125  is located near the center of the sipe blade  120 , and the sipe blade  120  is positioned so as to bisect the conduit  110  over a diameter of the conduit  110 . In an alternative embodiment, the notch is off-centered. In other alternative embodiments, sipe blade may not bisect the conduit. 
       FIG. 1  also shows a schematic of a generally cylindrical vent insert  135 , located within the conduit  110 . The top of vent insert  135  is positioned parallel to the interior surface  105  and to the notch  125 . The notch  125  is dimensioned to receive the vent insert  135 . The vent insert  135  can be mounted into the conduit  110  using any means known to one of ordinary skill in the art. The notch  125  may vary in depth, but in this embodiment, notch  125  has a depth matching the ‘sipe embedment depth’ of the sipe into the mold. The ‘sipe embedment depth’ (the depth to which the sipe blade  120  is embedded into the tire mold  100 ) is a design depth established by a designer, taking into account constraints of the particular application. The ‘sipe embedment depth’ in this embodiment ranges from 0.15 inches to 0.25 inches, but this range may be increased based on constraints of the application. 
       FIG. 2  illustrates a front view of an exemplary vent insert in a tire mold shown in cross section. It should be understood that the illustrated insert is merely exemplary and that any vent insert may be employed. The vent insert  135  includes a threaded portion  140  having a plurality of spiral channels  145 . Spiral channels  145  are formed in the threaded portion  140  and run continuously from a top  150  of the vent insert  135  and along a portion of a length of the vent insert  135 . Each spiral channel  145  defines an intake opening  155  located at the top  150  of the vent insert  135 . In other embodiments, the spiral channels may be replaced with straight channels. Any number of channels may be employed. Additionally, other types of vent inserts may be used without departing from the scope of the present disclosure, including but not limited to spring vents, drill vents, micro vents, or sinter vents. 
     With continued reference to  FIG. 2 , the vent insert  135  in this embodiment is a sprueless type vent insert. The exemplary vent insert  135  allows gas from the interior of the tire mold  100  to vent to an exterior of tire mold  100 , reducing or preventing the formation of tire sprues. When tire material is compressed or injected into the tire mold  100 , the air inside the tire mold  100  is displaced. The displaced air is forced into the intake openings  155 , through the channels  145 , out the threaded portion  140  and finally through the rest of conduit  110  until reaching an exterior of the tire mold  100 . The shape and size of the intake openings  155  prevent sprues from forming when tire material comes into contact with the interior surface  105  and the threaded portion top  150 . A designer can optimize the airflow through the channels  145  on each side of the vent by varying the size, geometry, location, or number of channels. 
     The threaded portion  140  in this exemplary vent insert  135  has an outer diameter approximately equivalent to an inner diameter of the conduit  110  and diameter of the opening  115 . In this embodiment, an equal number of intake openings  155  are located on either side of the sipe blade  120  when installed. However, other arrangements of the intake openings  155  may be used without departing from the scope of the present disclosure. For example an unequal number of vent intakes  155  may be located to either side of the sipe blade  120 . In alternative embodiments, a different type of vent insert may be used, or the vent insert may be omitted altogether. The diameter of the vent insert  135  can be optimized to accommodate the width of the sipe blade and the available mold surface area available. 
       FIG. 3  depicts a front view of an alternative embodiment of a sipe blade and a notched vent insert in a tire mold shown in cross section. In this embodiment, a tire mold  200  has an interior surface  205  and a conduit  210 . The conduit  210  includes an opening  215  that permits fluid communication between the interior of the tire mold  100  and an exterior (not shown) of the tire mold  100 . A vent insert  225  is located within the conduit  210 . The vent insert  225  is positioned so that a top portion is flush with the interior surface  205 . As in other embodiments, other types of vent inserts or other arrangements of vent inserts may be used without departing from the scope of the present disclosure. 
     In the embodiment shown in  FIG. 3 , the bottom edge of the sipe blade  220  does not include a notch. Rather, the bottom edge of the sipe blade  220  is straight, and located outside of the interior surface  205 . The vent insert  225  includes a vent insert notch  230  in a top portion thereof, which receives the sipe blade  220 . The vent insert notch  230  is positioned in a central diameter of the vent insert  225 . In this embodiment, the sipe blade  220  passes through the conduit opening  215 , and through the vent insert  225  via the vent insert notch  230 . The vent insert notch  230  has a width approximately equal to the thickness of the sipe blade  220 , to form a tight connection between the vent insert  225  and the sipe blade  220 . Alternatively, the vent insert notch may have a width greater than the blade thickness. Vent insert notch  230  may vary in depth, but in this embodiment, vent insert notch  230  has a depth matching the ‘sipe embedment depth’ of the sipe into the mold. The ‘sipe embedment depth’ (the depth to which the sipe blade  220  is embedded into the tire mold  200 ) is a design depth established by a designer, taking into account constraints of the particular application. The ‘sipe embedment depth’ in this embodiment ranges from 0.15 inches to 0.25 inches, but this range may be increased based on constraints of the application. 
     In an alternative embodiment (not shown), the vent insert notch may be located off-center of the vent insert, so that it is not positioned along a diameter of the vent insert. In such an embodiment, the sipe blade would not pass through a diameter of the conduit opening, and instead would pass through a distance less than the diameter of the conduit. 
       FIG. 4  illustrates a side view of the exemplary vent insert  225  of the  FIG. 3  embodiment. The vent insert  225  is substantially the same as the vent insert  150  of  FIGS. 1 and 2 , except for the addition of the notch  230  in a top portion of the vent insert  225  for receiving the sipe blade  220 . It should be understood that the illustrated insert is merely exemplary and that any vent insert may be employed. As in other embodiments, other types of vent inserts or other arrangements of vent inserts may be used without departing from the scope of the present disclosure. 
       FIG. 5  illustrates another alternative embodiment of a sipe vent structure in a tire mold shown in cross section. In this embodiment, a tire mold  300  comprises an interior surface  305  and a conduit  310 . The conduit  310  permits fluid communication between an interior of the tire mold  300  and an exterior (not shown) of the tire mold  300 . A vent insert  325  is located in conduit  310 . 
     A bottom edge of the sipe blade  315  includes a notch  320 . The notch  320  is dimensioned to the receive vent insert  325 . A top of the notch  320  is located outside of the interior surface  305 . Additionally, the vent insert  325  includes a vent notch  330  located on a top portion thereon, and aligned with the notch  320  of the sipe blade  315 . In this embodiment, the vent notch  330  is the same width as the sipe blade  315 . The bottom of the vent notch  330  is adjacent to a top of the notch  320  such that the vent notch  330  and the notch  320  form an interlocking engagement. In an alternative embodiment (not shown) a gap may be formed between the bottom of the vent notch  330  and the top of notch  320  of the sipe blade  315 . In another alternative embodiment, the vent insert notch  330  may have a width greater than the sipe blade thickness. 
     In yet another alternative embodiment (not shown), the vent insert notch may be located off-center of the vent insert, so that it is not positioned along a diameter of the vent insert. In such an embodiment, the sipe blade would not pass through a diameter of the conduit opening, and instead would pass through a distance less than the diameter of the conduit. 
     In the embodiment of  FIG. 5 , a top of the vent insert  325  is flush with the interior surface  305 . Other arrangements are possible without departing from the scope of the present disclosure. The notch  320  and the vent notch  330  may vary in depth, but in this embodiment meet at a depth slightly less than the ‘sipe embedment depth’ of the sipe into the mold. The ‘sipe embedment depth’ (the depth to which the bottom most edge of sipe blade  315  is embedded into the tire mold  300 ) is a design depth established by a designer, taking into account constraints of the particular application. The ‘sipe embedment depth’ in this embodiment ranges from 0.15 inches to 0.25 inches, but this range may be increased based on constraints of the application. 
       FIG. 6 a    depicts a top-down view of one possible arrangement of a sipe blade  400  and a vent structure  405 . In this arrangement, sipe blade  400  bisects venting structure  405 . This arrangement can be used for any of the embodiments disclosed herein. 
       FIG. 6 b    illustrates an alternative arrangement of the sipe blade  500 . The sipe blade  500  in this embodiment is segmented into three parts, each angled with respect to the adjacent segment. In this embodiment, any number of sipe blade segments may be used, and the sipe blades may be arranged to form any angles with respect to each other. Alternatively, three separate sipe blades may be arranged in this manner. This type of arrangement may be used with any of the above described embodiments of the sipe venting structure. One or more venting structures  505  may be located beneath the sipe blade  500 . The venting structures  505  may be any of the above described embodiments, and may include vent inserts, conduits, vents inserts with notches, etc. as described above. The sipe blade may also be a single curve, multiple curves, or a serpentine shape incorporating different radii. 
     To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.” Furthermore, to the extent the term “connect” is used in the specification or claims, it is intended to mean not only “directly connected to,” but also “indirectly connected to” such as connected through another component or components. 
     While the present application has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the application, in its broader aspects, is not limited to the specific details, the representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant&#39;s general inventive concept.