Patent Publication Number: US-8523635-B2

Title: Tire buffing debris collecting system

Description:
This application is a National Stage application of PCT Application No. PCT/US2007/072500, filed Jun. 29, 2007, to which this application claims priority and the benefit of, the disclosure of which is also hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to tire retreading and more specifically, to buffing machines for buffing tread from a crown of a tire. 
     2. Description of the Prior Art 
     Tires are known to comprise a tread consisting of an outer layer of rubber-based mixtures, of greater or lesser thickness, in which are molded various grooves and tread patterns intended, inter alia, to improve the vehicle&#39;s grip relative to the ground. 
     In certain cases, it is necessary to machine or remove the outer surface of the tire, for example, the tire tread, for the purpose of preparing a worn tire for retreading. Typically, tire tread removal has been accomplished by various types of cutting devices, such as rasps, grinding wheels, and wire brushes. Another process used for tire tread removal is a cutting process that utilizes a cylindrical cutter called a “peeler.” 
     During the tread removal process, it may be desirable to collect the debris removed from the tire. Material removed by the methods discussed above creates debris that is preferably collected for disposal. It is well known in the art to provide a collection removal system for this material; however, these prior art systems do not satisfactorily collect the debris. Therefore, there is a need to provide an improved system for collecting debris generated during a tread removal process. 
     SUMMARY OF THE INVENTION 
     Particular embodiments of the present invention include a debris collection system for collecting debris generated while buffing a tire casing on a tire buffing machine. The tire buffing machine includes a cutting head having a cutting surface that is rotatable about the cutting head axis. Particular embodiments of the system include a rotatable shroud being rotatable about a shroud axis, the shroud comprising a side member surrounding a majority of the cutting head cutting surface, a cutting head access window to expose the cutting head for buffing the tire casing, a vacuum suction port adjacent to the cutting head access window, and a shroud driver. The driver rotates the shroud during buffing, wherein rotating the shroud during buffing aligns the vacuum suction port with a projected path of debris discharged from the cutting head cutting surface. 
     Particular embodiments of the present invention further include methods for collecting debris generated while buffing a tire casing on a buffing machine. Such embodiments may include the steps of translating the cutting head across a tire to a subsequent location and rotating a shroud about a shroud axis to obtain an alignment of a vacuum suction port of the shroud with a projected path of debris discharged from the cutting head cutting surface. Particular embodiments are implemented with the shroud comprising a side member surrounding a majority of the cutting head cutting surface, a cutting access window to expose the cutting head cutting surface for buffing the tire casing, a vacuum suction port adjacent to the cutting access window and a shroud driver for rotating the shroud during buffing. Particular embodiments may further include the step of collecting the debris through the vacuum suction port. 
     Additional embodiments of the present invention include tire buffing machines having the debris collection systems described above. 
     The foregoing and other objects, features and advantages of the invention will be apparent from the following more detailed descriptions of particular embodiments of the invention, as illustrated in the accompanying drawing wherein like reference numbers represent like parts of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a dual head buffing (“tire buffing”) machine according to an embodiment of the present invention. 
         FIG. 2  is a front perspective view of a shroud of the machine identified in  FIG. 1  with a portion of the safety cover removed. 
         FIG. 3  is a rear perspective view of a shroud of the machine identified in  FIG. 1  showing the shroud in a safety position. 
         FIG. 4  is a front perspective view of a shroud of the machine identified in  FIG. 1  showing a cutaway portion of the shroud. 
         FIG. 5  is a perspective view of a processing unit of the machine identified in  FIG. 1 . 
         FIG. 6  is a top view of the buffing machine identified in  FIG. 1  engaging a tire along a central portion of the tread, in accordance with the present invention. 
         FIG. 7  is a top view of the buffing machine identified in  FIG. 1  engaging a tire tread near a shoulder of the tire, in accordance with the present invention. 
         FIG. 8  is a perspective view of a single-head buffing head of a tire buffing machine according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS 
     Particular embodiments of the present invention provide apparatus and methods for collecting debris generated while buffing a tire casing on a tire buffing machine. Such buffing of the tire removes an old tread from a tire casing to prepare the tire casing for a retreading operation. According to particular embodiments, the apparatus and methods provide a debris collection system having a shroud that rotates as the cutting head, which is the tread removal tool, translates across the tread of a tire. The shroud rotates to better align the collection portion of the system with a projected path of material being discharged from the cutting head cutting surface. 
     With reference to  FIGS. 1-5 , an exemplary example of the present invention is disclosed as a tire buffing machine  10  having a debris collection system. The buffing machine  10  includes two buffing units  14  operably mounted to a base  12  and a mounting unit  11  for mounting a tire  2 . Each buffing unit  14  translates along the base  12  to buff the tire  2  as desired. Further, the mounting unit  11  and/or the buffing units  14  may rotate (e.g., pivot) in relation to the other during the buffing process so that the buffing unit  14  buff a desired width of the tire  2 , including the tread  4 . By utilizing a servo, sensors, and the like, in conjunction with a controller  60 , the buffing machine  10  is able to determine and control the location and movement of the tire  2  with respect to each buffing unit  14 , while each translates and/or rotates with respect to the other. The controller  60  may also be used to control other aspects of the buffing machine  10 , including the rotation of the cutting head  18  and the rotation of shroud  30 , each of which is discussed in more detail below. It is contemplated that the tire  2  may be mounted on a mounting unit  11  that is separate from the buffing machine  10 . 
     The controller  60  includes a logic processor  61 , which may be a microprocessor, a memory storage device  62 , such as RAM (random access memory), ROM (read-only memory), PROM (programmable read-only memory), and at least one input/output (I/O) cable  66  for communicating with the buffing machine  10 . Further, the controller may include an I/O slot  63  for housing an I/O card having an I/O cable connector  64 . 
     An operator may utilize a user-interface  68  to monitor the buffing of the tire  2  and to program or otherwise control or instruct the operation of the controller  60  and the buffing machine  10 , which includes performing each step and method in accordance with this invention. The user-interface  68  and the controller  60  may communicate by way of an I/O cable  67 . It is also contemplated that wireless communications may exist between the controller  60 , the user-interface  68 , and the buffing machine  10 . 
     The controller  60  may be programmed by any known graphical or text language. Programmed instructions, data, input, and output may be stored in a memory storage device  62 , which is accessible to the processor  61 . The memory storage device  62  also stores inputs, outputs, and other information, such as, for example, profiles of treads, for use by the processor  61  in performing its operations. The memory device  62  may comprise any commercially known storage device, such as such as hard disk drives, optical storage devices, flash memory, and the like. The processor  61  executes programmed instructions and may perform the distance and/or positional calculations and measurements, as wells as other operations, discussed herein. 
     Each buffing unit  14  generally comprises a cutting head  18 , a cutting head motor  20 , a shroud  30 , and a shroud driver  44 . The components are generally mounted to a frame  16  for translation and/or rotation. The cutting head  18  includes a cutting head cutting surface  19  for buffing the tread  4  from the tire  2 . The cutting head  18  generally represents any tread removal tool, such as without limitation rasps, grinding wheels, and wire brushes. The rasp motor  20  rotates the cutting head  18  about a cutting head axis  22  in a clockwise and/or a counterclockwise direction. 
     The shroud  30  includes a cover  31 , which may comprise a side cover  32  and a lid  34 , a hinge  36 , a cutting head access window  38 , a guard plate  40 , and a vacuum suction port  43 . The cover  31  substantially contains the cutting head  18 , and therefore, it is contemplated that the cover  31  may comprise any design capable of substantially covering the cutting head  18 , whether or not such design uses a side cover  32  and lid  34  as disclosed herein. Between the lid  34  and the side cover  32 , a hinge  36  may exist. 
     Within the side cover  32  is a cutting head access window  38 , which provides the cutting head  18  access to engage the tire  2 . When the cutting head  18  is not engaging the tire  2 , the shroud  30  may rotate into a guarded position, where a guard plate  40  operates to substantially cover the cutting head access window  38 . To achieve this, it is contemplated that either the cover  31  or the guard plate  40  may rotate to align the cutting head access window  38  with the guard plate  40 . 
     To collect and discharge the debris removed from the tire by the cutting head  18 , a vacuum suction ductwork  42  is operably attached to the vacuum suction port  43  of the cover  31  (or side cover  32 ). In one embodiment, the vacuum port  43  is positioned adjacent to the cutting head access window  38 . More specifically, the vacuum suction port  43  is positioned to collect debris discharged from the cutting head  18  as it buffs the tire  2 , which is the side toward which the cutting head  18  rotates during engagement with the tire  2 . For example, in  FIG. 2 , the cutting head  18  is rotating across the cutting head access window  38  towards the vacuum port  43  (i.e., counter-clockwise about the cutting head axis  22 —from a top view perspective), which discharges the debris abraded from the tire  2  towards the vacuum port  43 . 
     The vacuum port  43  may include vacuum suction air flow to assist in the collection and removal of discharged material. Further, the opening and/or the ductwork  43  of the vacuum port  43  may be constricted or expanded to increase or decrease, respectively, the internal air velocity. Although not necessary, the air velocity may be equal to or greater than the velocity of the cutting head  18 , or the debris being discharged from the cutting head  18 . 
     In other embodiments, as shown in  FIG. 8 , the buffing machine  10 ′ may include a buffing unit  14 ′ having a cutting head motor  20  that rotates the cutting head  18 ′ in both clockwise and counterclockwise directions. Accordingly, the buffing unit  14 ′ is capable of buffing the tire tread  4  in both lateral (i.e., axial) directions across the tread  4 . Therefore, two vacuum ports  42 ′ may exist—each located on opposite sides of the cutting head access window  38  to collect debris discharged from the cutting head  18 ′ rotating in one of the two directions. This embodiment differs from the buffing unit  14  shown in  FIGS. 1-7 , which generally buffs in one direction across the tread  4 . 
     The shroud driver  44  provides rotational capabilities to the shroud  30 . In particular embodiments, a drive gear  48  extends from the shroud driver  44  to engage a shroud gear  50 . The shroud gear  50  is operably attached to the shroud  30  to cause the shroud  30  to rotate about the shroud axis  46 . In one embodiment, the cutting head axis  22  and shroud axis  46  are parallel to each other; however, it is contemplated that the axes  22 ,  46  may be skewed with respect to each other or may comprise the same axis. 
     In particular embodiments, the shroud driver  44  may comprise any linear or rotational motor or drive, including, without limitation, an electric motor, an air motor, a servo, a stepper motor, an actuator, a cylinder, or the like. In particular embodiments, the shroud driver  44  is a motor that provides a constant torque or force for rotating the shroud  30 . It is contemplated that other means known to one skilled in the art may be used in lieu of gears  48 ,  50  to transfer force from driver  44  to rotate shroud  30 , including, without limitation, friction plates, chains, and linkages. 
     To control the rotation of shroud  30 , a guide  52  may be attached to the shroud  30  or otherwise extend therefrom to engage the tire  2  when the buffing head is buffing the tire. The guide  52  generally extends from the shroud  30  near the cutting head access window  38  on the side of vacuum port  43  (i.e., the side of debris discharge). The guide  52  operates to limit the rotation of the shroud  30 , while maintaining a clearance distance between the shroud  30  and tire  2 . 
     The guide  52  may comprise a roller, a wheel, a bar or any other device known to one skilled in the art that does not interfere with the rotation of the tire  2  or the movement of the buffing head  18  during the buffing process. For example, it is contemplated that the guide  52  may comprise dual or multiple rollers or a single roller having an increased width. The increased width advantageously increases the contact patch of the guide on the tire  2 , thereby reducing the rolling resistance or binding associated with a small contact patch as the guide  52  travels across the tread  4  during a buffing operation. For example, a guide  52  having a small contact patch may become entangled in a tread or gouge in the tire tread, thereby interfering with the rotation of the tire  2  or movement of the buffing head  18  during the buffing process. 
     Optionally, for example, the guide  52  may comprise a bar across the cutting head access window  38 , extending to the same extent beyond the cutting head access window  38  as the rollers  52  shown, for example, in  FIG. 4  or  8 . It is also contemplated that the guide  52  may freely pivot, or otherwise be fixed at an angle relative to the tire&#39;s direction of rotation about the axle of the mounting unit  11 , while the tire  2  is being buffed to help reduce the resistance exhibited upon the guide  52  as it travels across the tread  4  during a tire buffing operation. 
     In operation, and with specific reference to  FIGS. 6-7 , the shroud driver  44  applies a rotational force to the shroud gear  50  via the drive gear  48 . The rotational force is thereby transferred to the guide  52 , which forces the guide  52  against tire  2  during the buffing process. As the cutting head  18  translates across the width of the tire tread, the rotational force generated by the shroud driver  44  forces the guide  52  to follow the curvature of the tire tread surface. As a consequence of the guide  52  being forced to follow the tread curvature, the shroud  30  rotates, thereby maintaining the cutting head access window  38  and vacuum port  43  in a position better aligned with the path of debris being discharged from the cutting head  18 . 
     If the shroud  30  did not rotate as needed during the buffing operation, the gap between the discharge side of the cutting head access window  38  and the tire  2  would grow as the cutting head  18  approached the tire shoulder  6  (i.e., the side of the tire). Upon reaching the tire shoulder  6 , the guide  52  may translate about and down the shoulder  6  and even along sidewall  8  of tire  2 . This causes the shroud  30  to rotate further about the shoulder  6  and thereby better align the vacuum port  43  with the discharge path of the debris being discharged from the cutting head  18 . 
     In alternative particular embodiments, an example of which is shown in  FIG. 8 , a buffing machine  10 ′ includes a second guide  52 ′ since the buffing unit  14 ′ buffs in both lateral directions across the tread  4  (as described above). 
     It is also contemplated that proximity sensors or switches, or the like, may be used to properly control the rotation of the shroud  30  or the guard plate  40  between a guarded position and a buffing position. 
     In other particular embodiments, the rotation of the shroud  30  may be controlled without a guide  52  when the shroud driver  44  is a positional control device, such as, without limitation, a servo, a stepper motor, and the like. The positional control device may provide linear or rotational output, and may operate by way of an electric motor, or otherwise utilize hydraulics, pneumatics, or magnets. Further, the control device may include a positional feedback device or may use a controller  60  (such as, for example, a PLC or other digital or analogue control known to those having ordinary skill in the art) to control the movement and position of the shroud  30 . 
     In particular embodiments, the positional control driver  44  rotates the shroud  30  in relation to the tread profile or shape as the cutting head  18  translates across the tread  4 . It is contemplated that the actual or estimated tread profile or shape may be input into a controller or selected from a plurality of profiles stored in the controller memory (such as memory storage device  62 ). Further, it is contemplated that the buffing machine  10  may instead monitor the tread location and/or tread profile or shape to determine how and when to rotate the shroud  30  to better align the vacuum port  43  with the flow of debris being discharged from the cutting head  18 . Knowing the width of the cutting head access window  38  may be useful in determining the rotational position of the shroud  30  and the amount of rotation necessary to adjust the shroud  30  as the cutting head  18  translates across tread width. It is contemplated this embodiment may also include a proximity sensor to monitor the gap between the shroud  30  and the tire  2 . 
     Particular embodiments of the present invention further include methods for collecting debris generated while buffing a tire casing on a tire buffing machine, such machines having been discussed above. Such methods may include the steps of translating the cutting head of the buffing machine across a tire to a subsequent location and rotating a shroud about a shroud axis to obtain an alignment of a vacuum suction port of the shroud with a projected path of debris discharged from the cutting head cutting surface. Such methods may further include the step of collecting the debris through the vacuum suction port. 
     Particular embodiments of such methods include, for example a shroud that comprises a side member surrounding a majority of the cutting head cutting surface, a cutting access window to expose the cutting head cutting surface for buffing the tire casing, and a vacuum suction port adjacent to the cutting access window. 
     Particular embodiment of the present invention may further include the step of controlling rotation of the shroud to maintain the alignment of the vacuum suction port with the projected path of debris discharged from the cutting head cutting surface. The method may further include the step of rotating the shroud about a shoulder of the tire. 
     The step of controlling rotation of the shroud to maintain the alignment may comprise, in particular embodiments, the step of causing the rotation of the shroud by a servo, a controller, a guide or combinations thereof, wherein the guide extends from the shroud to contact the tire during buffing. In particular embodiments, the method may further include the step of applying a constant force by the driver for rotating the shroud during buffing. Such a step provides that the guide is pressed against the tire surface during the buffing operation, thereby providing an alignment between the vacuum suction port and the projected path of the debris discharged from the cutting head cutting surface. 
     Particular embodiments of the present invention may further include the step of rotating the shroud between a guarded position and a buffing position, the cutting head access window being covered by a guard plate when in the guarded position. 
     While this invention has been described with reference to particular embodiments thereof, it shall be understood that such description is by way of illustration and not by way of limitation. Accordingly, the scope and content of the invention are to be defined only by the terms of the appended claims.