Patent Description:
In general, retreading involves replacing the tread on worn tires. Retreading preserves approximately <NUM> percent of the material in worn tires. The material cost associated with retreading is substantially less than the cost of manufacturing a new tire, and retreading permits significant recycling.

In a retreading process, a tire casing may be first inspected, which may involve visual and/or machine-based (e.g., shearographic) inspection to identify non-visible damage and embedded debris (e.g., nails). If the casing passes the initial inspection, the worn tread may be removed through a process referred to as buffing.

Buffing typically may involve removing excess rubber to provide a substantially evenly-textured crown for receiving a pre-cured tread strip and to provide a predetermined tire casing profile. Tire casings typically may include a belt package (a package of steel belts or cables) underlying the road-engaging surface (e.g., the original tread) of the tire. Prior to retreading, the casing may be buffed, generally to a predetermined characteristic crown radius corresponding to the upper contour of the belt package. The casing may be buffed to leave only a predetermined thickness, e.g., <NUM> (<NUM>/<NUM> of an inch), of material remaining over the top belt. The shoulder of the casing may also be buffed (trimmed) to eliminate or reduce voids or patterns in the shoulder created by the original tread, and to provide, typically, a relatively continuous profile between the casing sidewalls and the crown. A worn casing from each of various models and sizes of new tires has a characteristic tire casing profile of a particular crown width, crown buffing radius and shoulder trim angle which may be created as an initial step in the buffing process.

After being buffed, the tire casing may then be examined for injuries, which may be skived and filled with a repair gum. After completion of the skiving process, the buffed surface may be sprayed with tire cement that provides a tacky surface for application of a suitable layer of bonding material, such as cushion gum. The cushion gum may be a layer of uncured rubber material, which optionally may include a low temperature vulcanizing agent and accelerator. The cushion gum can be placed over the crown. In some retreading operations, the spray cement can be omitted.

A cured tread strip, typically of a width corresponding to the width of the crown of the casing, may then be cut to the length corresponding to the casing circumference and disposed over the casing crown. Alternatively, continuous replacement treads in the shape of a ring (i.e., ring treads) may be used to retread the buffed casing. A roller pressing process, commonly referred to as stitching, may be performed on the assembly to force air from between the tread strip and casing.

After stitching the tire assembly, which includes the tire casing, the cushion gum and the tread, the assembly may be placed within a flexible rubber envelope. An airtight seal can be created between the envelope and the bead of the tire casing. The entire envelope, with the tire assembly disposed therein, can be placed within a curing chamber and subjected to elevated pressure and temperature for a predetermined period of time. The combination of exposure to elevated pressure and temperature for a duration of time may bind the cushion gum to both the tire casing and the new tire tread.

Buffing in the noted process may be performed by a buffing apparatus including a rasp and a tire mounted so that the rasp may come into contact with the tire's outer surface. An operator may perform an initial inspection process to analyze the current condition of a tire casing. The tire casing may then be mounted to the tire hub assembly. For example, the tire hub assembly may include a tire chuck with an expandable rim for accepting tire casings of various sizes. After buffing has been completed the operator may remove the tire and send it to another location for further processing.

Buffing and skiving processes take approximately <NUM> minutes per tire. Of the <NUM> minutes, the buffing process takes approximately <NUM> minutes, loading and unloading take approximately <NUM> seconds each, and skiving takes approximately <NUM> seconds. In addition, the rasp head must come to a complete stop after completing a buffing process, and must be restarted to buff the next tire. When operating at production rate, this corresponds to approximately <NUM> start/stop sequences per hour. Each start/stop sequence requires a substantial in-rush of current into the rasp motor in order to accelerate the rasp head to bring the rasp head up to operating speed. Energy is also needed to bring the rasp head to a stop. The start/stop sequences also stress and ultimately reduce the useful life of the components of the rasp head, thereby requiring regular maintenance. Prior art document <NUM> (<CIT>) discloses a tire casing preparation system including a transfer machine and associated with a plurality of work stations for performing a variety of operations on worn tire casings such as de-treading, contouring, surface conditioning, dimensional gauging, defect detection and adhesive treatment. The transfer machine includes a turntable having a plurality of chucking and rotating mechanisms for mounting and processing tire casings as they are moved from one work station to another.

The invention is related to an apparatus according to independent claim <NUM> and to a method according to independent claim <NUM>. As disclosed herein, an example apparatus includes a turntable having a first end and an opposite second end. The turntable is rotatable about a central axis between a first position and a second position. A first expandable hub is rotatably coupled to the turntable proximate the first end. The first expandable hub is configured to receive a first tire casing. A second expandable hub is rotatably coupled to the turntable proximate the second end. The second expandable hub is configured to receive a second tire casing. A rasp head is positioned to operatively engage the first tire casing on the first expandable hub when the turntable is in the first position to perform a buffing operation on the first tire casing, and the rasp head is positioned to operatively engage the second tire casing on the second expandable hub when the turntable is in the second position to perform a buffing operation on the second tire casing.

As disclosed herein, another example apparatus includes a rasp pedestal. A circular track surrounds the rasp pedestal. A first carrier is operatively coupled to the track and is movable along the track between a first position and a second position. The first position is adjacent the rasp pedestal. A second carrier is operatively coupled to the track separated from the first carrier. The second carrier is movable between first and second positions. The second position is adjacent the rasp pedestal. A first expandable hub is rotatably coupled to the first carrier. The first expandable hub is configured to receive a first tire casing. A second expandable hub is rotatably coupled to the second carrier. The second expandable hub is configured to receive a second tire casing. The first expandable hub is positioned for buffing of the first tire casing when the turntable is in the first position. The second expandable hub is positioned for buffing of the second tire casing when the turntable is in the second position.

As disclosed herein, an example method includes permitting a buffing operation on a first tire casing operatively coupled to a first expandable hub. While performing the buffing operation on the first tire casing, the method includes (<NUM>) performing a skiving operation on a second tire casing operatively coupled to a second expandable hub mounted on the turntable separate from the first expandable hub; (<NUM>) unloading the second tire casing from the second expandable hub; (<NUM>) loading a third tire casing onto the second expandable hub; and (<NUM>) rotating the first expandable hub from a first position to a second position for performing a skiving operation while simultaneously rotating the second expandable hub from a second position to a first position for performing a buffing operation.

The features of the present invention will become apparent to one of ordinary skill in the art upon reading the detailed description, in conjunction with the accompanying drawings, provided herein. The embodiments provided herein are not intended to limit the invention to such embodiments, but instead are provided with the understanding that changes and modifications may be made within the scope of the claimed invention.

<FIG> is a plan view of a dual tire buffing apparatus <NUM>, according to an embodiment. The dual tire buffing apparatus <NUM> includes a base assembly <NUM>, a rasp pedestal <NUM>, a rasp pedestal moving assembly <NUM>, fencing <NUM>, an electrical enclosure <NUM>, a pneumatic enclosure <NUM>, and an human-machine interface (HMI) terminal <NUM>. The dual tire buffing apparatus <NUM> also includes a dual tire hub assembly <NUM>. The dual tire hub assembly <NUM> of the dual tire buffing apparatus <NUM> enables multiple tire casings to be processed at the same time. As will be appreciated, the dual tire buffing apparatus <NUM> provides significant time and energy savings.

The rasp pedestal <NUM> includes a rasp head assembly <NUM> rotatably coupled to the rasp pedestal <NUM>. The rasp head assembly <NUM> can include a rasp head <NUM> and a texturing device <NUM>. The rasp head <NUM> is structured to remove material from the tire casing being buffed. The texturing device <NUM> is structured to impart a desired texture on at least a portion of the tire casing. In one embodiment, the texturing device <NUM> includes a wire brush. A rasp drive motor (not shown) is structured to controllably drive the rasp head assembly <NUM>. More specifically, the rasp drive motor is structured to rotate a shaft upon which one or both of the rasp head <NUM> and the texturing device <NUM> may be mounted.

The rasp pedestal moving assembly <NUM> is configured to controllably move the rasp pedestal <NUM> relative to the dual tire hub assembly <NUM> along each of an X-axis, a Y-axis, and a Z-axis. In some embodiments, the rasp pedestal moving assembly <NUM> may be controlled automatically via a control unit (not shown) housed in the electrical enclosure <NUM>. In other embodiments, the rasp pedestal moving assembly <NUM> is controlled semi-automatically or manually by an operator via the HMI terminal <NUM>.

The fencing <NUM> extends around at least a portion of the rasp pedestal <NUM>, the rasp pedestal moving assembly <NUM>, and the dual tire hub assembly <NUM>, so as to prevent objects from unintentionally entering or exiting the operational area of the dual tire buffing apparatus <NUM>. The electrical enclosure <NUM> and the pneumatic enclosure <NUM>, and the HMI terminal <NUM> may each be positioned external to the fencing <NUM>.

The dual tire buffing apparatus <NUM> also includes a swing arm <NUM>. The swing arm <NUM> is positioned such that the dual tire hub assembly <NUM> is disposed intermediate the swing arm <NUM> and the rasp pedestal <NUM>. The swing arm <NUM> includes a secondary buffing and texturing head <NUM> configured to perform secondary buffing and texturizing operations on tire casings. Although not shown in <FIG>, other embodiments may include material collection systems proximate one or both of the rasp pedestal <NUM> and the swing arm <NUM> to collect material removed from tire casings.

The dual tire hub assembly <NUM> of the dual tire buffing apparatus <NUM> also includes first and second expandable hubs <NUM>, <NUM> operatively coupled to a turntable <NUM>. The turntable <NUM> is rotatable between first and second positions. In each position, a buffing operation can be performed on one tire casing loaded on one of the first and second expandable hubs <NUM>, <NUM>, while skiving, unloading, and loading operations are performed on other tire casings on the other of the first and second expandable hubs <NUM>, <NUM>. Thus, a single operator can operate the dual tire buffing apparatus <NUM> to buff a first tire casing while skiving and unloading a second tire casing and subsequently loading a third tire casing. In many situations, skiving, unloading, and loading operations may be performed in less time than it takes to complete the buffing operation. Accordingly, the dual tire buffing apparatus <NUM> enables significant time savings over prior tire buffing systems. The dual tire buffing apparatus <NUM> configuration also enables the rasp head to be continuously rotated rather than being stopped between each buffing process. Accordingly, the dual tire buffing apparatus <NUM> also provides energy savings over prior tire buffing systems, while further reducing wear and tear on the rasp head.

As shown in <FIG>, the turntable <NUM> includes a turntable hub <NUM>, which is rotatable about a central axis <NUM>. The turntable also includes a first arm <NUM> extending from the turntable hub <NUM> to a first end <NUM>, and a second arm <NUM> extending from the turntable hub <NUM> to a second end <NUM> opposite the first end <NUM>. In some embodiments, the first and second arms <NUM>, <NUM> are defined by a single elongate member. The first and second arms <NUM>, <NUM> are rigidly coupled to the turntable hub <NUM> such that rotation of the turntable hub <NUM> causes corresponding rotation of the first and second arms <NUM>, <NUM> of the turntable <NUM>, and therefore, of the first and second expandable hubs <NUM>, <NUM>.

The turntable <NUM> is shown in <FIG> in the first position. In the first position, the first expandable hub <NUM> is positioned proximate the rasp pedestal <NUM>. In the first position, the rasp head <NUM> is configured to engage a first tire casing (not shown) on the first expandable hub <NUM> to perform a buffing operation on the first tire casing. In addition, the second expandable hub <NUM> is positioned proximate the swing arm <NUM> so as to perform skiving and unloading operations on a second tire casing (not shown) on the second expandable hub <NUM>, and to subsequently load a third tire casing (not shown) onto the second expandable hub <NUM>.

<FIG> illustrates the turntable <NUM> of <FIG> as partially rotated between the first and second positions. More specifically, the turntable <NUM> is being rotated counter-clockwise about the central axis <NUM> so that the first expandable hub <NUM> moves towards the swing arm <NUM>, and the second expandable hub <NUM> moves towards the rasp pedestal <NUM>. In other embodiments, the turntable <NUM> rotates clockwise. In some embodiments, the turntable <NUM> is configured for <NUM> degree rotation. In other embodiments, the turntable <NUM> is configured for <NUM> degree rotation. In one embodiment, rotation between the first and second positions may take about six seconds. In another embodiment, rotation between the first and second positions may take less than ten seconds.

<FIG> illustrates the turntable <NUM> of <FIG> and <FIG> in the second position. As illustrated in <FIG>, the first expandable hub <NUM> is positioned proximate the swing arm <NUM>, and the second expandable hub <NUM> is positioned proximate the rasp pedestal <NUM>. It can be seen that the position of the first and second expandable hubs <NUM>, <NUM> is switched between the first and second positions.

With reference to <FIG>, various arrangements of the dual tire buffing apparatus <NUM> will be described in reference to first, second, and third tire casings. It should be understood that the first tire casing is operatively coupled to the first expandable hub <NUM>. The second tire casing is operatively coupled to the second expandable hub <NUM>. The second tire casing should be understood to have already completed a buffing process by the rasp head <NUM>. The third tire casing should be understood as being next in queue to be processed after the first and second tire casings.

The rasp head <NUM> is positioned to operatively engage the first tire casing on the first expandable hub <NUM> when the turntable <NUM> is in the first position to perform a buffing operation on the first tire casing, and to operatively engage the second tire casing on the second expandable hub <NUM> when the turntable <NUM> is in the second position to perform a buffing operation on the second tire casing. The rasp head <NUM> is rotated relative to the rasp pedestal <NUM> to perform the buffing operation. In some embodiments, the rasp head is continuously rotated while performing buffing operations on a plurality of tire casings.

The first expandable hub <NUM> is positioned for skiving of the first tire casing when the turntable <NUM> is in the second position (<FIG>), and the second expandable hub is positioned for skiving of the second tire casing when the turntable <NUM> is in the first position (<FIG>). The first expandable hub <NUM> is configured to accept and release the first tire casing when the turntable <NUM> is in the second position (<FIG>). The second expandable hub is configured to accept and release the second tire casing when the turntable <NUM> is in the first position (<FIG>).

The swing arm <NUM> is positioned to operatively engage the second tire casing on the second expandable hub <NUM> when the turntable <NUM> is in the first position (<FIG>), and to operatively engage the first tire casing on the first expandable hub <NUM> when the turntable <NUM> is in the second position (<FIG>). The swing arm <NUM> may be configured to impart a predetermined texture upon the shoulders of each of the first and second tire casings.

<FIG> is a plan view of a dual tire buffing apparatus <NUM>, according to another embodiment. As shown in <FIG>, the dual tire buffing apparatus <NUM> includes a base assembly <NUM>, a rasp pedestal <NUM> and rasp pedestal moving assembly <NUM>. The rasp pedestal moving assembly <NUM> is mounted to the base assembly <NUM>, and the rasp pedestal <NUM> is mounted to the rasp pedestal moving assembly <NUM>. The rasp pedestal <NUM> includes a rasp head <NUM> rotatably coupled to the rasp pedestal <NUM>.

The dual tire buffing apparatus <NUM> also includes a circular track <NUM> surrounding the rasp pedestal <NUM> and the rasp pedestal moving assembly <NUM>. First and second carriers <NUM>, <NUM> are operatively coupled to the track <NUM> on opposite sides thereof. The first and second carriers <NUM>, <NUM> are movable on the track <NUM> between first and second positions. In the first position, the first carrier <NUM> is adjacent the rasp pedestal <NUM>. In the second position, the second carrier <NUM> is adjacent the rasp pedestal <NUM>.

A first hub assembly <NUM> including a first expandable hub <NUM> is mounted to the first carrier <NUM>, such that the first expandable hub <NUM> is rotatable relative to the first carrier <NUM>. The first expandable hub <NUM> is configured to receive a first tire casing <NUM>. A second hub assembly <NUM> including a second expandable hub <NUM> is mounted to the second carrier <NUM>, such that the second expandable hub <NUM> is rotatable relative to the second carrier <NUM>. The second expandable hub <NUM> is configured to receive a second tire casing <NUM>.

The dual tire buffing apparatus <NUM> also includes a swing arm <NUM>. The swing arm <NUM> is positioned outside of the track <NUM> opposite the rasp pedestal <NUM>. The swing arm <NUM> includes a secondary buffing and texturing head <NUM> configured to perform secondary buffing and texturizing operations on tire casings.

The dual tire buffing apparatus <NUM> may also include fencing <NUM> at least partially surrounding the rasp pedestal <NUM> so as to prevent objects from objects from unintentionally entering or exiting the operational area proximate the rasp pedestal <NUM>. According to an embodiment, as illustrated in <FIG>, the fencing <NUM> may be disposed inside of the track <NUM> such that the track <NUM> surrounds the fencing <NUM>. The swing arm <NUM>, as well as electrical and pneumatic enclosures <NUM>, <NUM>, may be disposed external to the track <NUM>.

Similar to the dual tire buffing apparatus <NUM> of <FIG>, the dual tire buffing apparatus <NUM> of <FIG> is configured to perform a buffing operation on one tire casing loaded on one of the first and second expandable hubs <NUM>, <NUM>, while simultaneously performing skiving, unloading, and loading operations on other tire casings on the other of the first and second expandable hubs <NUM>, <NUM>. For example, the dual tire buffing apparatus <NUM> is shown in <FIG> in the first position. In the first position, the first carrier <NUM> is positioned proximate the rasp pedestal <NUM> and the second carrier <NUM> is positioned proximate the swing arm <NUM>. Accordingly, in the first position, the first tire casing <NUM> mounted to the first expandable hub <NUM> is positioned to undergo a buffing operation, and the second tire casing <NUM> mounted to the second expandable hub <NUM> is positioned to undergo a skiving operation and to be unloaded. A third tire casing (not shown) may subsequently be loaded and mounted onto the second expandable hub <NUM>.

<FIG> illustrates the dual tire buffing apparatus <NUM> of <FIG>, with the first and second carriers <NUM>, <NUM> of <FIG> shown as partially rotated between the first and second positions. More specifically, the first and second carriers <NUM>, <NUM> are being rotated clockwise along the track <NUM> so that the first expandable hub <NUM> moves towards the swing arm <NUM>, and the second expandable hub <NUM> moves towards the rasp pedestal <NUM>. In other embodiments, the first and second carriers <NUM>, <NUM> rotate counter-clockwise. In some embodiments, the first and second carriers <NUM>, <NUM> are configured for <NUM> degree rotation around the track <NUM>. In other embodiments, the first and second carriers <NUM>, <NUM> are configured for <NUM> degree rotation along the track <NUM>. In one embodiment, rotation between the first and second positions takes six seconds. In another embodiment, rotation between the first and second positions takes less than ten seconds.

<FIG> illustrates the first and second carriers <NUM>, <NUM> of <FIG> and <FIG> in the second position. As illustrated in <FIG>, the first expandable hub <NUM> is positioned proximate the swing arm <NUM>, and the second expandable hub <NUM> is positioned proximate the rasp pedestal <NUM>. It can be seen that the position of the first and second expandable hubs <NUM>, <NUM> is switched between the first and second positions.

<FIG> is a plan view of a dual tire buffing apparatus <NUM>, according to another embodiment. As shown in <FIG>, the dual tire buffing apparatus <NUM> is generally similar to the dual tire buffing apparatus <NUM> of <FIG>. However, the dual tire buffing apparatus <NUM> includes an electrical enclosure <NUM>, a pneumatic enclosure <NUM>, an HMI terminal <NUM>, and a swing arm <NUM>, each positioned inside of a track <NUM>. In other words, the track <NUM> surrounds each of the electrical enclosure <NUM>, the pneumatic enclosure <NUM>, the HMI terminal <NUM>, and the swing arm <NUM>.

In another embodiment, instead of having two tire drives or hubs that rotate relative to the rasp pedestal, an example apparatus includes two stationary tire drives, and a rasp pedestal rotates relative to the tire drives. In this embodiment, an operator must walk between each tire drive to skive and unload a finished tire casing, and to load the next tire casing. In a further embodiment, tire hubs are transmitted vertically (e.g., between floors of a building) instead of rotationally on a single floor.

In other embodiments, additional carriers may be mounted to increase the number of tires in process. For example, in <FIG>, additional carriers may be added half-way between the shown carriers so that carriers would be present at <NUM> degrees (first carrier <NUM>), <NUM> degrees, <NUM> degrees (second carrier <NUM>), and <NUM> degrees around the periphery.

<FIG> is a flow diagram of a method <NUM> of simultaneously performing buffing and skiving operations on tire casings, according to an embodiment. For example, the method <NUM> may be performed in connection with any of the dual tire buffing apparatus <NUM>, <NUM>, or <NUM> of <FIG>. However, it should be understood that the method <NUM> is not limited to these example embodiments.

At step <NUM>, a buffing operation is performed on a first tire casing operatively coupled to a first expandable hub. The buffing operation may be performed by controllably engaging a rasp head with the first tire casing and moving the rasp head along a predetermined path relative to the first tire casing so as to remove worn tread from the first tire casing. The first tire casing is buffed to achieve a desired tire casing profile. The buffing operation may also include imparting a desired texture on at least a portion of the tire casing.

Steps <NUM>-<NUM> are performed simultaneous to step <NUM>. At <NUM>, a skiving operation is performed on a second tire casing operatively coupled to a second expandable hub. The second tire casing has been buffed prior to undergoing the skiving operation at <NUM>. Skiving can involve inspecting the buffed tire casing for injuries, which are skived and filled with a repair gum. The skiving process at <NUM> may also include performing a secondary buffing and texturizing operation on the second tire casing.

At <NUM>, the second tire casing is unloaded from the second expandable hub upon completion of the skiving operation at <NUM>. Upon unloading the second tire casing from the second expandable hub, the remaining retreading processes may be performed on the second tire casing so as to provide a complete retreaded tire.

At <NUM>, a third tire casing is loaded onto the second expandable hub. The third tire casing is in queue to be buffed and skived subsequent to the first and second tire casings.

At <NUM>, upon completing steps <NUM>, as well as steps <NUM>-<NUM>, a turntable of the dual tire buffing assembly may be rotated so as to move the dial tire buffing assembly from a first position to a second position. Upon the turntable being rotated to the second position, a buffing process is performed on the third tire casing, and skiving and unloading processes are performed on the first tire casing.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise indicated.

Claim 1:
An apparatus (<NUM>), comprising:
a base (<NUM>) comprising a first arm (<NUM>) extending from a central axis toward a first base end (<NUM>) and a second arm (<NUM>) extending from the central axis (<NUM>) toward a second base end (<NUM>), the first base end (<NUM>) opposite the second base end (<NUM>), wherein the base (<NUM>) is rotatable about the central axis between a first position and a second position, wherein the first arm (<NUM>) and the second arm (<NUM>) are coupled to the base (<NUM>);
a first hub (<NUM>) coupled to the first arm (<NUM>), the first hub (<NUM>) configured to receive a first tire casing, the first hub (<NUM>) coupled to the first arm (<NUM>) such that a diameter of the first tire casing is substantially perpendicular to the first arm (<NUM>); and
a second hub (<NUM>) coupled to the second arm (<NUM>), the second hub (<NUM>) configured to receive a second tire casing, the second hub (<NUM>) coupled to the second arm (<NUM>) such that a diameter of the second tire casing is substantially perpendicular to the second arm (<NUM>), wherein the first hub (<NUM>) and the second hub (<NUM>) are respectively coupled to the first arm (<NUM>) and the second arm (<NUM>) such that rotation of the base (<NUM>) causes rotation of the first arm (<NUM>) and the second arm and (<NUM>) of the first hub (<NUM>) and the second hub (<NUM>), characterized by;
a buffing member (<NUM>) positioned to operatively engage the first tire casing on the first hub (<NUM>) when the base (<NUM>) is in the first position to perform a first buffing operation on the first tire casing, the buffing member (<NUM>) positioned to operatively engage the second tire casing on the second hub (<NUM>) when the base (<NUM>) is in the second position to perform a second buffing operation on the second tire casing, wherein the buffing member (<NUM>) is configured to remove worn tread.