Abstract:
A tire uniformity machine for analyzing a tire having a process controller in communication with a plurality of sensors for determining the physical characteristics of the tire, the marking assembly comprising a positioning assembly near the tire uniformity machine and in communication with the process controller; a marker operatively attached to the positioning assembly such that upon receiving a signal from the process controller the positioning assembly locates the marker in operative relation to the tire.

Description:
RELATED PATENT APPLICATIONS 
     None. 
     FIELD OF THE INVENTION 
     The present invention generally relates to tire uniformity machines. More particularly, the present invention relates to a marking mechanism for a tire uniformity machine. Most specifically, the present invention relates to a marker that is automatically positioned for application of a mark on a tire in a continuous process. 
     BACKGROUND OF THE INVENTION 
     Tire uniformity machines may be used to detect the high or low point of fundamental harmonic of radial force variation within the tire. When measuring the tire force variations, a computer analyses of the high or low point phase angle of the radial force variation first harmonic from an event mark (zero angle). The event mark is set on the tire spindle shaft in conjunction with a pulse generator and pulses once per revolution. After measurement is complete, the tire rotation speed is accelerated, the high or low point of the tire is indexed and stopped beneath a marker head. A heated marking pin is lowered against the upper side wall of the inflated tire by actuation of an air cylinder. The heated pin transfer pigment or metal foil from a tape to place a mark on the sidewalls of the tire at the high or low point. 
     While the mark is automatically applied by actuation of the pneumatic cylinder, the position of the marking apparatus must be manually adjusted for each tire cross section and diameter. In other words, for tires of different diameters or cross section, the marking apparatus must be manually moved vertically or horizontally to accommodate the change in tire size. 
     While this manual adjustment is suitable for batch operating systems, tire production increasingly relies on continuous production of tires of varying sizes. Consequently, there is a need for a marking apparatus that can automatically adjust to accommodate changes in tire size as the tires come through the uniformity machine. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a marking assembly in a tire uniformity machine that is capable of automatically adjusting to accommodate tires of various size. 
     In furtherance of this object, the present invention provides a marking assembly, in a tire uniformity machine for analyzing a tire having a process controller in communication with a plurality of sensors for determining the physical characteristics of the tire, the marking assembly comprising a positioning assembly in communication with the process controller; a marker operatively attached to the positioning assembly such that upon receiving a signal from the process controller the positioning assembly locates the marker in operative relation to the tire and causes the marker to apply a mark to the tire. 
     The present invention further provides a marking assembly, in a tire uniformity machine having a process controller wherein the machine receives a test tire, the marking assembly comprising a positioning assembly near the uniformity; and a first marker operatively located with respect to the tire and a second marker opposite the first marker in similar relation to the tire, whereby upon receiving a signal from the process controller, the positioning assembly locates the first and second markers on either side of the tire for applying a pair of marks thereto. 
     The present invention further provides a method of automatically marking a tire, in a tire uniformity machine that receives test tires and determines their physical characteristics including the tire diameter and axial height, a method comprising providing the tire diameter and axial height to a process controller which causes a marker to move relative to the tire upon determining a change in the tire size and signaling the marker to apply a mark to the tire once the marker is in position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmented side elevational view of a marking apparatus according to the present invention showing the marking apparatus as it might be located within a tire uniformity machine in relation to the test tire. 
     FIG. 2 is a fragmented top elevational view as might be seen along line  2 — 2  in FIG.  1 . 
     FIG. 3 is a side elevational view as might be seen along line  3 — 3  in FIG.  1 . 
     FIG. 4 is an enlarged view of the marking apparatus with the cover removed to show the internal components thereof. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A marking assembly according to the present invention is referred to generally by the numeral  10  in the accompanying drawings. In FIG. 2, marking assembly  10  is depicted as it might be found in a tire uniformity machine U. These machines are well known in the art and, therefore, the discussion of the tire uniformity machine will be made in general terms only. A typical tire uniformity machine may have a plurality of frame elements on which various testing and shaping equipment are mounted. A conveyor C or other transport mechanism brings a tire T into the uniformity machine for testing. Often tire T is chucked and placed in contact with a load wheel. The load wheel is equipped with various sensors to obtain information about the tire, including the tire&#39;s dimensions, as it causes the tire to rotate. In some instances, grinding elements are used to correct irregularities found during this testing. Once the testing is complete an event mark is applied to the tire by marking assembly  10 . To that end, marking assembly  10  generally includes a marker  15  and a positioning assembly  20 . 
     Marking assembly  10  may be located proximate to the tire T, during testing, or it may be moved into position when the testing is completed. Similarly, the marking assembly may be attached to the uniformity machine U or mounted on its own frame. The marking assembly  10  may be globally positioned according to practices common in the art. With respect to the tire T the marking assembly  10  is selectively moveable to accommodate tires T of various size. In a continuous process tires T of differing sizes may arrive at the marking assembly  10 . To accommodate the changes in tire size including diameter and axial height, the marking assembly  10  is moved in an automated fashion. 
     As shown in FIG. 1, marker  15  within marking assembly  10  may be moved horizontally to accommodate tire diameter and vertically to accommodate the tire&#39;s axial height. 
     The movement of marker  15  may be accomplished with a variety of known positioning assemblies  20  including belt drive systems, stepper motor systems, or linear tables among others. As shown in FIG. 1, the positioning assembly  20  may be mounted on a frame  12  (shown schematically). As previously discussed, the positioning assembly  20  may include a variety of actuators for moving the marker  15  in relation to a tire T. One positioning assembly  20 , shown in FIG. 3, includes a first actuator  21  and a second actuator  22  in operative relation with marker  15 . Referring to FIG. 1, second actuator  22  may be attached to a frame  23 . Frame  23  is, in turn, operatively attached to first actuator  21 . Thus, the frame  23  and second actuator  22  may be translated by first actuator  21  along its axis, in this case horizontally. Alternatively, the second actuator  22  may carry the first actuator  21 , or independent actuators may be used. Further, it is envisioned that a single actuator having multiple degrees of freedom may be used to position the marker  15 . Second actuator  22  moves marker  15  in the vertical direction. As shown, first actuator  21  is oriented horizontally and second actuator  22  is vertical in relation to a tire T carried in a horizontal configuration. It will be appreciated that tire T may be vertically or otherwise oriented within the uniformity machine U and thus actuators  21 ,  22  may be oriented differently than shown to accommodate the orientation of the tire. 
     Actuators  21 ,  22  are shown as linear tables, which are well known in the art, and generally include a motor M operatively engaging a table member  24  which is generally mounted on a pair of rails  25 . A wide variety of linear tables are available in the art and include screw drive, stepper motor and servo-motor mechanisms. Some examples of which are shown in  Manual and Motorized Positioning Systems,  catalog 000-9132-01 Parker Motion and Control DAEDAL pp. B1-B88 (1996 Parker-Hanafin Corporation). Other examples are shown in catalog numbers 000-9134-01, 000-9141-02, 9143/USA, and 2042/USA by Parker-Hanafin Corporation. It will be appreciated that if a second marker  15 ′ is used, an additional positioning assembly  20 ′ may be used including separate actuators, or, as shown in phantom, the additional marking assembly  10 ′ may be mounted on a third actuator  22 ′ with both assemblies  10  and  10 ′ being mounted on the first actuator  21 . In this way, first actuator  21  positions second actuator and third actuator  22 ,  22 ′ relative to one dimension of the tire, in this case the diameter, and the second and actuators  22 ,  22 ′ adjust to the remaining dimension, in this case axial height. 
     Focusing on the marker  15 , a variety of suitable devices capable of applying indicia to a tire&#39;s surface including hot stamp markers may be used. One example of which is shown in FIG.  4 . In FIG. 4, the cover of a typical hot stamp marker  15  has been removed to show the internal components which include a marking pin  31  and marking tape (not shown). The marking pin  31  is typically driven against the tape by air pressure. Air is provided to the marker  30  by hoses attached to the marker at pneumatic fittings  32 ,  33  which deliver air to a mark cylinder  34 . The mark cylinder  34  drives the pin assembly  35  downward to place a mark and retracts the pin  31  after the mark has been made. A rack gear  36  carried by pin assembly  35  actuates a spur gear  37  which is operatively connected to the tape roll  38  (in phantom), such that the motion of the pin  31  advances the tape. To ensure proper contacting of the marking pin  31 , the marker  15  may be rotatably or otherwise moveably mounted to the frame  23 , and driven into contact by a fluid cylinder  40  or other means. The contacting means may include a motorized lever arm, a spring or other brasing member, or other conventional mechanism for bringing the marker into contact with the tire. Conversely, the cylinder may be used to retract the marker  15  once the mark has been placed on the tire T. As will be appreciated, the entire marking assembly  10  may be controlled by a suitable process controller (not shown). The process controller may be in communication with suitable sensors for determining the diameter and axial height of the tire transmitting a signal to the controller, which, in turn, adjusts the position of the marking assembly  10  by causing actuation of the positioning assembly  20 . Once the marking assembly  10  is in position, the controller may send a signal to activate the cylinder  40  to place the marker  30  near the surface of tire T, and provide air to the pneumatic fittings driving the pin  31  into contact with the tape pressing the tape against the tire to leave a mark. After placing the mark, the controller would retract the marker  30  and await the next tire. 
     It should thus be apparent that the above-described invention satisfies one or more of the objects stated above. While a full and complete description of the invention has been set forth in accordance with the dictates of the patent statutes, it should be understood that modifications can be resorted to without departing from the spirit hereof or the scope of the appended claims.