Patent Description:
The production of tires includes the step of placing an uncured tire within a mold at which time heat and pressure is applied to the uncured tire in order to change its state to a cured condition. During the curing process, the uncured tire is placed inside of a metal mold that surrounds the exterior of the uncured tire. An expandable rubber bladder is positioned inside of the uncured tire, when it is within the mold, and is expanded to apply pressure to the inside surface of the uncured tire. The pressure applied by the expandable bladder forces the uncured tire against the mold to cause the uncured tire to be under pressure forces. Heat may be simultaneously applied, and the combination of heat and pressure applied for a particular time effects the curing process. The cured tire may then be removed from the mold and transported downstream for subsequent processing.

The expandable bladder when inflated and applying force causes the crown portion of the tire to be forced against a garniture of the mold that includes a series of features that form grooves, sipes, and tread blocks of the tire to result in the formation of the tread design of the tire. The garniture can be made of two or more multiple sections that are arranged in a circle. A production mold segment <NUM> is shown in <FIG> and features that are used to form the architecture of the tread are shown. In forming a teardrop longitudinal sipe of the tread, a series of sipe sections are present in the production mold segment <NUM>. A first sipe element <NUM> is located next to a second sipe element <NUM> which is likewise located next to a third sipe element <NUM>. The sipe elements <NUM>, <NUM>, <NUM> are not completely aligned next to one another. For example, a misalignment <NUM> exists between the first and second sipe elements <NUM>, <NUM> such that the teardrop forming portions of these elements <NUM>, <NUM> are out of alignment by the misalignment <NUM>. The other portions of the sipe elements <NUM>, <NUM> can likewise be misaligned, and it is also the case that the portions of the second and third sipe elements <NUM>, <NUM> are likewise misaligned to one another. Molding of the tire with the misaligned sipe elements <NUM>, <NUM>, <NUM> causes the resulting teardrop longitudinal sipe in the tire to have sections that are stepped and otherwise misaligned. The misalignments may be in the teardrop sections or the narrow portions or both of the teardrop longitudinal sipe. As multiple production mold segments <NUM> are present in the garniture, if all or a portion of them include misaligned sipe elements then multiple steps and misalignments are present within the final teardrop longitudinal sipe. This may cause poorer hydrodynamical behavior for the tire.

In order to form the production mold segment <NUM>, the casting process employs a gypsum/plaster cast segment that includes the sipe elements <NUM>, <NUM>, <NUM>. In order to form the gypsum cast segment, a flexible cast segment is used and into this flexible cast segment the sipe elements <NUM>, <NUM>, <NUM> are inserted. The sipe elements <NUM>, <NUM>, <NUM> are aligned next to one another for use in forming the teardrop longitudinal sipe in the tire. The sipe elements <NUM>, <NUM>, <NUM> may not be placed precisely in alignment with one another and their positions may shift during the subsequent casting processes into which the sipe elements <NUM>, <NUM>, <NUM> are transferred to the gypsum cast segment and the production mold segment <NUM>. Misalignment of the sipe elements <NUM>, <NUM>, <NUM> in the casting process results in a teardrop longitudinal sipe in the tire that has irregularities. As such, there remains room for variation and improvement within the art.

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, which makes reference to the appended Figs.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention.

Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations.

A mold segment <NUM> is provided that has a first sipe element <NUM> and a second sipe element <NUM> that feature male and female connectors <NUM>, <NUM>. The male and female connectors <NUM>, <NUM> can be engaged to cause the sipe elements <NUM>, <NUM> to be connected to one another when placed into the mold segment <NUM>. The positions of the sipe elements <NUM>, <NUM> will be maintained during the different steps of the casting process to keep teardrop sections <NUM>, <NUM> of the sipe elements <NUM>, <NUM> aligned so that the resulting production mold segment <NUM> will have aligned teardrop sipe architecture.

With reference to <FIG>, a tire <NUM> is illustrated in perspective view that has a central axis <NUM> that serves as the axis of rotation of the tire <NUM>. The central axis <NUM> extends through the center of the tire <NUM> and is aligned in the axial direction. The radial direction <NUM> of the tire <NUM> extends outward from the central axis <NUM> and is perpendicular to the central axis <NUM>. The tire <NUM> also has a circumferential direction that extends around the circumference of the tire <NUM> and circles the central axis <NUM>. The circumferential direction may be located at any distance from the central axis <NUM> in the radial direction <NUM> of the tire <NUM>, and need not be located only at the tread <NUM> or the outer most portion of the tire <NUM> in the radial direction <NUM>. The tire <NUM> has tread <NUM> that may feature various tire architecture such as tread blocks, grooves, sipes, and ribs. The tread <NUM> shown has two teardrop longitudinal sipes <NUM> that extend around the entire circumference of the tread <NUM>. In this regard, the teardrop longitudinal sipes <NUM> extend <NUM> degrees around the central axis <NUM>. Although not shown in <FIG>, other tire architecture of the tread shown could include lateral sipes that are located in the three sections formed by the shoulder edges of the tread <NUM> and the two teardrop longitudinal sipes <NUM>. A sipe is defined as a groove of the tread <NUM> that has a width that is <NUM> millimeters or less. The grooves of the tread <NUM> may thus be grooves that have widths that are greater than <NUM> millimeters. The widths of the sipes can be measured at the surface of the tread <NUM> when the tread <NUM> is new and not worn, as in some instances the teardrop sections of the sipes, if they have them, may in fact be larger than <NUM> millimeters. Although no grooves are shown, it is to be understood that in other arrangements they may be present. The sipes and grooves can take on any shape and extend in any direction such as angled, curved, or zig-zag. Although two teardrop longitudinal sipes <NUM> are shown, it is to be understood that the mold segment <NUM> that is used to form the tire <NUM> may be arranged to form only a single teardrop longitudinal sipe <NUM> in other embodiments. As such, the mold segment <NUM> may be used to form a tire with one or more teardrop longitudinal sipes <NUM> with any other tread <NUM> architecture such as additional sipes, grooves, ribs, etc. A pair of sidewalls extend from the crown of the tire <NUM> on either side in the axial direction <NUM> towards the center in the radial direction <NUM>. Depending upon the tire <NUM> geometry, some features of the tread <NUM>, such as lateral sipes (if present) and grooves, may extend into the sidewalls as well.

<FIG> is a cross-sectional view taken along line <NUM>-<NUM> of <FIG> and shows the cross-sectional shapes of the teardrop longitudinal sipes <NUM>. Although not shown in the illustrated embodiment, the lateral sipes could be small cuts in the tread that maintain the same cross-sectional profile along their entire depth, although this need not be the case in other embodiments. The teardrop longitudinal sipes <NUM> have a narrow section less than <NUM> millimeters extending from the surface of the tread <NUM> into the tread. The teardrop longitudinal sipes <NUM> then at the bottom of this narrow section open up into a larger void that is wider, and in some cases may be greater than <NUM> millimeters, than the narrow section. The shape of this larger void can be round, rectangular, oval, or of any shape. When new, this larger void is hidden from view as it is within the interior of the tread <NUM>. Wear of the tread <NUM> causes the rubber to be worn off until the larger void is exposed and imparts desired properties onto the performance of the tread <NUM> during use.

<FIG> shows a mold <NUM> for curing a tire <NUM>. A tire <NUM> that is made of uncured rubber is placed into the mold <NUM> and cured via heat and pressure applied by the mold <NUM>. The mold <NUM> can be configured in a variety of ways. In the embodiment illustrated, the mold <NUM> includes a garniture <NUM> that has a series of production mold segments <NUM> that engage the tire <NUM> to form the tread <NUM> of the tire <NUM>. The mold <NUM> also includes a top mold section <NUM> and a bottom mold section <NUM> that engage the sidewalls of the tire <NUM> and form the sidewall portions. In other arrangements, additional top and bottom mold sections <NUM>, <NUM> can be included and thus multiple other components may be present in the mold <NUM> for forming the tire <NUM>. The green/unmolded tire <NUM> can be placed inside of the garniture <NUM> and the top and bottom mold sections <NUM>, <NUM> may be moved into engagement with the garniture <NUM>. An inflatable bladder is placed through one of the sections <NUM>, <NUM> and inside of the tire <NUM> and is inflated in order to press the tire <NUM> against the tread producing elements of the production mold segments <NUM> and against the insides of the top and bottom mold sections <NUM>, <NUM>. Heating elements can be located within the various production mold segments <NUM> or they may be otherwise heated in order to transfer heat into the tire <NUM> that is within in the mold <NUM>. In this manner, the mold <NUM> is capable of applying heat and pressure to the tire <NUM> that is within the mold <NUM>. Although described as all being moveable, it may be the case that some of the elements production mold segments <NUM> are not movable while others are in fact movable to open and close the mold <NUM>. The production mold segments <NUM> may be movable in that they move relative to the ground onto which the mold <NUM> rests.

The bladder can be inflated with air, steam, liquid, nitrogen, or any other fluid to cause it to expand to force the tire <NUM> against the tread and sidewall forming portions of the mold <NUM>. After sufficient heat and pressure are applied to the tire <NUM> for a sufficient amount of time, the bladder can be deflated and the top and/or bottom mold sections <NUM>, <NUM> can be moved away from the garniture <NUM> to allow the cured tire <NUM> to be removed for subsequent processing.

With reference to <FIG>, the garniture <NUM> of the mold <NUM> is made of a plurality of production mold segments <NUM> that extend <NUM> degrees about an axis. The production mold segments <NUM> may be in engagement with one another, or a small space could be present between the production mold segments <NUM>. In some arrangements, the production mold segments <NUM> can move in the radial direction towards the central axis to further add pressure to the tire <NUM> during curing. In other instances, the production mold segments <NUM> are stationary and do not move in the radial direction. The production mold segments <NUM> can be the same size as one another, or may be different sizes from one another. Although <NUM> production mold segments <NUM> are shown, it is to be understood that the garniture <NUM> can include any number of production mold segments <NUM> in other arrangements. For example, from <NUM>-<NUM> production mold segments <NUM> can be included in the garniture <NUM> in other versions of the mold <NUM>. Still further, although described as having production mold segments <NUM>, the garniture <NUM> could in fact be composed of zero production mold segments <NUM> in other arrangements in which the garniture <NUM> is a single, solid piece that extends around its central axis. The production mold segments <NUM> thus engage the tire <NUM> during formation, and include the various sipe elements such as the first sipe element <NUM> and the second sipe element <NUM> that are used to form the teardrop longitudinal sipe <NUM> of the tire <NUM> upon molding by the mold <NUM>.

In order to make the production mold segment <NUM>, the mold making process can employ a gypsum cast segment that includes embedded in it sipe making elements and those used to make the teardrop longitudinal sipe <NUM> such as the first and second sipe elements <NUM>, <NUM>. The first and second sipe elements <NUM>, <NUM> are embedded into the production mold segment <NUM> so that the teardrop sections <NUM>, <NUM> are more into the gypsum and the narrow sections <NUM>, <NUM> extend more out of and away from the gypsum. The gypsum cast segment also has various features that are imparted into the production mold segment <NUM> such as grooves, ribs, and shoulder features. The gypsum cast segment is a positive image of the tread <NUM>. Hot aluminum is poured onto the gypsum cast segment which then hardens and takes on the features of the gypsum cast segment and the exposed pieces such as the sipe making elements are embedded into the production mold segment <NUM>. The narrow sections <NUM>, <NUM> may be those that are embedded into the production mold segment <NUM>. The gypsum may be machined off as desired in order to complete the production mold segment <NUM>.

In order to create the gypsum cast segment, the molding process may use a mold segment <NUM>, one example of which is illustrated with reference to <FIG>. The mold segment <NUM> has some flexibility in it and may sometimes be referred to as a flexible cast segment <NUM>. The mold segment <NUM> may be made out of castable mold rubber such as polysulfide rubber. The mold segment <NUM> has a mold segment base <NUM> and it is this base <NUM> that can include the polysulfide rubber and be somewhat flexible. The various features in the mold segment base <NUM> that form the architecture of the tread <NUM> can be made out of the flexible material. Additionally, the first and second sipe elements <NUM>, <NUM> can be placed into the mold segment base <NUM> at this stage of the production process, and these first and second sipe elements <NUM>, <NUM> may be eventually transferred to the production mold segment <NUM> and engage the tire <NUM> to form the teardrop longitudinal sipe <NUM> during curing. The first and second sipe elements <NUM>, <NUM> are pushed into the flexible mold segment base <NUM> and held therein by the gripping force of the flexible mold segment base <NUM>. The first and second sipe elements <NUM>, <NUM> are interlocked with one another via a connection described herein so that their position relative to one another remains constant and does not vary during the production process. The mold segment <NUM> features three sipe elements interlocked with one another and pressed into the mold segment base <NUM>. An additional three interlocked sipe elements are next to these three to form the adjacent teardrop longitudinal sipe <NUM>. Although three interlocked sipe elements are disclosed, any number of two or more sipe elements can be present in the mold segment base <NUM>. As the mold segment base <NUM> may be curved for forming the eventual curved surface section of the tire <NUM>, the sipe elements can be arranged so that they are interlocked not linearly but instead have some angled arrangement to accommodate some or all of the curvature of the mold segment base <NUM>. The sipe elements <NUM>, <NUM> inserted into the mold segment base <NUM> may engage it only at the bottom, or various feature forming portions of the mold segment base <NUM> can touch the sipe elements <NUM>, <NUM> on their sides as well. The sipe elements <NUM>, <NUM> are arranged into the mold segment base <NUM> so that narrow sections <NUM>, <NUM> extend out of the mold segment base <NUM> and the teardrop sections <NUM>, <NUM> are farther away from this point of extension.

<FIG> illustrate a first sipe element <NUM> in accordance with one exemplary embodiment. The first sipe element <NUM> can be made out of a rigid material such as steel or aluminum, and may include a relatively flat first sipe element narrow section <NUM> that is used to form the narrow sipe section of the teardrop longitudinal sipe <NUM>. At the bottom of the first sipe element narrow section <NUM>, a first sipe element embedded end <NUM> is present and has a first sipe element void <NUM>. The first sipe element embedded end <NUM> is pressed into the mold segment base <NUM> and buried therein when forming the mold segment <NUM>, and the first sipe element narrow section <NUM> can remain exposed. The first sipe element void <NUM> may be dovetail in shape, but can be variously shaped in other exemplary embodiments. The first sipe element embedded end <NUM> may be integrally formed with the first sipe element narrow section <NUM>. The first sipe element <NUM> also includes a first sipe element teardrop section <NUM> located at an end of the first sipe element narrow section <NUM>. The first sipe element teardrop section <NUM> is the portion of the first sipe element <NUM> used to form the teardrop portion of the teardrop longitudinal sipe <NUM> and is wider than the first sipe element narrow section <NUM>.

The first sipe element teardrop section <NUM> is offset from the first sipe element narrow section <NUM> in the length direction, and is not movable relative to the first sipe element narrow section <NUM>. The first sipe element <NUM> has a first terminal end <NUM> which is the farther portion of the first sipe element <NUM> in one direction. The first sipe element teardrop section <NUM> is located at the first terminal end <NUM>, and the first sipe element narrow section <NUM> is not located at the first terminal end <NUM>. The first sipe element teardrop section <NUM> is offset from the first sipe element narrow section <NUM> such that an offset <NUM> is measured from the first terminal end <NUM> to the first sipe element narrow section <NUM>. On the opposite side, the first sipe element <NUM> has a first sipe element second terminal end <NUM> and the first sipe element narrow section <NUM> is located at the first sipe element second terminal end <NUM>. The first sipe element teardrop section <NUM> is spaced from and is not located at the first sipe element second terminal end <NUM>. In some embodiments, the offset <NUM> is one millimeter.

The first sipe element <NUM> has a female connector <NUM> located at the first terminal end <NUM>. The female connector <NUM> is formed by a slot <NUM> defined in the first sipe element teardrop section <NUM> and the slot <NUM> is a vertical slot that extends completely through the first sipe element teardrop section <NUM> and extends the same distance as the offset <NUM> into the first sipe element teardrop section <NUM>. <FIG> shows the first sipe element <NUM> spaced from and not in engagement with a second sipe element <NUM>. The second sipe element <NUM> can be arranged the same way as the first sipe element <NUM> and the previous description of the first sipe element <NUM> may be applied to the second sipe element <NUM>. In this regard, the second sipe element <NUM> has a second sipe element embedded end <NUM> that with a second sipe element narrow section <NUM> defines a second sipe element void <NUM>. The second sipe element teardrop section <NUM> has a length <NUM>, and in some instances the length <NUM> is the same as the length of the second sipe element narrow section <NUM>. The second sipe element <NUM> has a first terminal end <NUM> at which the second sipe element narrow section <NUM> is located. An oppositely disposed second terminal end <NUM> of the second sipe element <NUM> is present and the second sipe element teardrop section <NUM> is located at the second terminal end <NUM>. The teardrop sections <NUM>, <NUM> may be connected to the other portions of the sipe elements <NUM>, <NUM> by any manner such as crimping, welding, brazing, mechanical fasteners, or integral formation. This connection may be permanent, or it may be a removable connection.

The second sipe element teardrop section <NUM> is offset <NUM> from the first terminal end <NUM> and the second sipe element teardrop section <NUM> is not located at the first terminal end <NUM>. The second sipe element <NUM> has a first leg <NUM> and a second leg <NUM> that are spaced from one another a distance <NUM>. The legs <NUM>, <NUM> are integrally formed with the second sipe element narrow section <NUM> and may be of the same width as the second sipe element narrow section <NUM>. A void exists between the legs <NUM>, <NUM> in the length direction. The first leg <NUM> has a length <NUM> in the longitudinal direction, and the second leg <NUM> has a length <NUM> in the longitudinal direction. The lengths <NUM> and <NUM> may be the same in some embodiments. The second sipe element <NUM> has a male connector <NUM> located at the first terminal end <NUM>. The male connector <NUM> is composed of the first leg <NUM> and is that portion of the first leg <NUM> that is exposed via the offset <NUM>. In accordance with some exemplary embodiments regarding the second sipe element <NUM>, the length <NUM> must be at a minimum <NUM> millimeters, and the length <NUM> must be at a minimum <NUM> millimeters, and the length <NUM> between the two legs <NUM> and <NUM> must be at least <NUM> millimeters. In some exemplary embodiments, the offset <NUM> is one millimeter, and the offset <NUM> is one millimeter.

The female connector <NUM> and male connector <NUM> can be engaged with one another to lock the position of the first sipe element <NUM> to the second sipe element <NUM>. <FIG> shows the two sipe elements <NUM>, <NUM> moved into engagement with one another so that the female connector <NUM> engages the male connector <NUM>. Although the two can be separated by pulling them apart, the elements <NUM>, <NUM> are described as connected because through their engagement they cannot move in at least some directions such as closer to one another, or to the left or right of one another. Engagement of the two sipe elements <NUM> and <NUM> allows them to be inserted into the mold segment base <NUM> so that their relative positions to one another will not change during the mold <NUM> building process. By maintaining their relative positions, the resulting production mold segment <NUM> will have features for forming the teardrop longitudinal sipe <NUM> that are more closely aligned with one another so that steps are eliminated or reduced.

The connection results from moving the first leg <NUM> of the second sipe element <NUM> into the slot <NUM> of the first sipe element teardrop section <NUM>. The first leg <NUM> is sized relative to the slot <NUM> so that it is tightly received therein. The offset <NUM> distance is the same as the distance of offset <NUM> so that the first terminal end <NUM> engages the first sipe element narrow section <NUM>. The second sipe element teardrop section <NUM> engages the first sipe element teardrop section <NUM> when the female and male connectors <NUM>, <NUM> are connected. The geometry of the first terminal end <NUM>, the end of the second sipe element teardrop section <NUM>, the first terminal end <NUM>, and/or the first sipe element narrow section <NUM> can be arranged so that the first and second sipe elements <NUM>, <NUM> are angled relative to one another when the connectors <NUM>, <NUM> are engaged as shown in <FIG>. Alternatively, the geometry can be arranged so that the first and second sipe elements <NUM>, <NUM> when connected are not angled relative to one another but are parallel to one another. The angled arrangement may allow the connected sipe elements <NUM>, <NUM> to better conform to the concave curvature of the mold segment base <NUM> when forming the round section of the tire <NUM>. <FIG> shows the first and second sipe elements <NUM>, <NUM> connected and parallel to one another when connected. The drawing also shows a third sipe element <NUM> connected and parallel to the first sipe element <NUM>. Male and female connectors <NUM>, <NUM> can be present on opposite ends of the sipe elements so that two sipe elements can be connected thereto. Also, in some embodiments, the sipe element could have two male connectors <NUM> one opposite ends for connection to two sipe elements, or may have two female connectors <NUM> on opposite ends for connection to two sipe elements. When assembled as a network of sipe elements, each adjoining sipe element will have interconnections to the next to align them together.

The sipe elements can be configured in a variety of different manners in accordance with other embodiments of the mold segment <NUM>. The first sipe element narrow section <NUM> of the first sipe element <NUM> is shown in <FIG>. The first sipe element void <NUM> has a dovetail shape and is at the end of the first sipe element <NUM> that includes the first sipe element embedded end <NUM>. The void <NUM> need not be dovetail shaped in other embodiments. The opposite end includes a pair of the legs as previously discussed that are separated from one another by a distance such that a void is present between the legs. Although the legs are illustrated as being square in shape, they may be rectangular, circular, triangular, or variously shaped in accordance with other exemplary embodiments. A variation of the sipe element is shown in <FIG> in which the second sipe element <NUM> is illustrated that features but a single first leg <NUM>. No other legs of the second sipe element <NUM> are present except for this single first leg <NUM> of the second sipe element <NUM>. The single first leg <NUM> is located at both terminal ends <NUM>, <NUM> such that it extends the entire length of the second sipe element <NUM>. The second sipe element narrow section <NUM> likewise is located at the terminal ends <NUM>, <NUM>. The second sipe element teardrop section <NUM> can be retained onto the first leg <NUM> via any possible mechanism such as crimping, welding, integral formation, or mechanical fasteners. The length <NUM> can be the same as the length of the first leg <NUM>, but the second sipe element teardrop section <NUM> can be offset from the first leg <NUM> so that a female connector <NUM> and male connector <NUM> are formed. Alternatively, the length <NUM> can be longer or shorter than the length of the first leg <NUM> so that at least one female connector <NUM> and/or male connector <NUM> are formed.

<FIG> shows another alternative exemplary embodiment of the second sipe element <NUM> that is different from those previously discussed in that a third leg <NUM> is present along with a pair of second sipe element teardrop sections <NUM> instead of just a single teardrop section. The third leg <NUM> is located between the first leg <NUM> and the second leg <NUM> in the length direction of the second sipe element <NUM>. A void is present between the first leg <NUM> and the third leg <NUM>, and a void is present between the third leg <NUM> and the second leg <NUM>. The legs <NUM>, <NUM>, <NUM> may all be sized and shaped the same. The pair of second sipe element teardrop sections <NUM> includes two of the sections and they are both retained onto the three legs <NUM>, <NUM>, <NUM>. A first one of the pair <NUM> engages the first leg <NUM> and the third leg <NUM>, and a second one of the pair <NUM> engages the third leg <NUM> and the second leg <NUM>. The pair <NUM> may abut one another so that a discontinuity is not formed in the resulting teardrop longitudinal sipe <NUM>. The pair <NUM> has a length <NUM> that extends in the longitudinal direction of the second sipe element <NUM> which may be the same as the length of the second sipe element narrow section <NUM>. The pair <NUM> can be offset <NUM> from the second sipe element narrow section <NUM> to form the male connector <NUM> as previously discussed. The pair <NUM> can be oriented linearly with respect to one another, or they can be slightly angled against one another to allow for some amount of curvature to be imparted into the to be molded teardrop section of the teardrop longitudinal sipe <NUM>.

The sipe elements <NUM>, <NUM> can be arranged so that the length <NUM> is from <NUM> millimeters to up to but not including <NUM> millimeters and so that a single leg <NUM>, and no more than one, is present and a single teardrop section <NUM>, <NUM>, and no more than one, is present. Further, if such a sipe element <NUM>, <NUM> is provided and the length <NUM> is <NUM> millimeters up to but not including <NUM> millimeters, then the length of the slot <NUM> which may be the offset <NUM> is equal to one third of the length <NUM>. The sipe elements <NUM>, <NUM> can be arranged so that two legs <NUM> and <NUM> are present and a single teardrop section <NUM>, <NUM>, and no more than one, is present and so that the length <NUM> is from <NUM> millimeters up to but not including <NUM> millimeters. In another embodiment, the sipe elements <NUM>, <NUM> may be arranged so that three legs <NUM>, <NUM>, <NUM> are present, and a pair of the teardrop sections <NUM> are present, and so that the length <NUM> is <NUM> millimeters or greater.

The sipe elements as discussed may include a female connector <NUM> on one end and a male connector <NUM> on an opposite end. However, variations are possible in which only one of the connectors <NUM> or <NUM> is present in the sipe element. <FIG> shows the second sipe element <NUM> with a male connector <NUM> on one end as previously discussed. A pair of legs <NUM>, <NUM> are present, and the length <NUM> is less than the length of the second sipe element narrow section <NUM>. In this regard, the second terminal end <NUM> has both the second sipe element narrow section <NUM> and the second sipe element teardrop section <NUM> located thereon. The second leg <NUM> is also located at the second terminal end <NUM>. These three components <NUM>, <NUM>, and <NUM> end in a planar surface at the second terminal end <NUM>. There is no female connector <NUM> or male connector <NUM> at the second terminal end <NUM>. A second sipe element <NUM> of this configuration may be used at the end of a series of sipe elements disposed within the mold segment base <NUM>. The third sipe element <NUM> of <FIG> likewise does not have a male or female connector <NUM>, <NUM> located at one of its terminal ends.

<FIG> illustrates an alternative exemplary embodiment in which the first sipe element <NUM> has a female connector <NUM> located at the first terminal end <NUM> as discussed in previous embodiments. The first sipe element second terminal end <NUM> does not have a male or female connector <NUM>, <NUM>. Instead, the various elements such as the first sipe element teardrop section <NUM>, the narrow section, and the leg end at the first sipe element second terminal end <NUM> and may end in a plane in some embodiments. The length of the first sipe element teardrop section <NUM> can be longer than the length of the narrow section. As such, the sipe elements can be constructed so that only the female connector <NUM> is present and the male connector <NUM> is not present.

<FIG> shows a further exemplary embodiment in which the first sipe element <NUM> has a first sipe element narrow section <NUM> but does not have a void at the first sipe element embedded end <NUM>. The first sipe element <NUM> does have a pair of legs on an end opposite the first sipe element embedded end <NUM>. The first sipe element teardrop section <NUM> is offset from the first sipe element narrow section <NUM> in the longitudinal direction and male and female connectors can be defined on opposite ends of the first sipe element <NUM>. The first sipe element teardrop section <NUM> has angled, or tilted, ends and not ends that are parallel or substantially parallel to the ends of the first sipe element narrow section <NUM>. The first terminal end <NUM> is the location at the first sipe element teardrop section <NUM> located at a position farthest from the first sipe element embedded end <NUM>. The length of the angled first sipe element teardrop section <NUM> illustrated is measured between the closer of the two points of the opposite ends of the angled first sipe element teardrop section <NUM>.

The description of the mold segment <NUM> includes various illustrations and descriptions of different designs of the first sipe element <NUM> and the second sipe element <NUM>. It is to be understood that this is for sake of convenience and that all design aspects associated with the first sipe element <NUM> could be associated with those of the second sipe element <NUM>. Likewise, all design aspects of the second sipe element <NUM> could be associated with those of the first sipe element <NUM>. The interlocked sipe elements <NUM>, <NUM> may result in the elimination of visible steps in the tread of the tire <NUM>.

Claim 1:
A mold segment (<NUM>; <NUM>) for forming a tire (<NUM>), comprising:
a first sipe element (<NUM>) that has a first sipe element narrow section (<NUM>) and a first sipe element teardrop section (<NUM>), wherein the first sipe element (<NUM>) has a female connector (<NUM>);
a second sipe element (<NUM>) that has a second sipe element narrow section (<NUM>) and a second sipe element teardrop section (<NUM>), wherein the second sipe element (<NUM>) has a male connector (<NUM>); and
a mold segment base (<NUM>) that receives the first sipe element (<NUM>) and the second sipe element (<NUM>), wherein the female connector (<NUM>) of the first sipe element (<NUM>) receives the male connector (<NUM>) of the second sipe element (<NUM>),
characterized in that
the first sipe element teardrop section (<NUM>) is located at a first terminal end (<NUM>) of the first sipe element (<NUM>), and wherein the first sipe element narrow section (<NUM>) is offset from the first terminal end (<NUM>) of the first sipe element (<NUM>) and not located at the first terminal end (<NUM>) of the first sipe element (<NUM>);
the first leg (<NUM>) is located at the first terminal end (<NUM>) of the second sipe element (<NUM>), and wherein the second sipe element narrow section (<NUM>) is located at the first terminal end (<NUM>) of the second sipe element (<NUM>);
the male connector (<NUM>) is located at a first terminal end (<NUM>) of the second sipe element (<NUM>), wherein the second sipe element teardrop section (<NUM>) is offset from the first terminal end (<NUM>) of the second sipe element (<NUM>) and not located at the first terminal end (<NUM>) of the second sipe element (<NUM>).