Abstract:
A valve stem installation system includes a robotic arm for moving a valve stem insertion device around the lip of wheel. The system also includes a pair of valve stem aperture sensors positioned on the robotic arm adjacent the valve stem insertion device and moveable around the lip of the wheel. The sensors can be positioned on opposite sides of the valve stem insertion device. When the first sensor locates the valve stem aperture, movement of the robotic can be slowed. When the second sensor locates the valve stem aperture, movement of the robotic arm can be stopped. The conveyor unit can include an identification station to sense the configuration of the wheel. A controller can select the appropriate valve stem to insert in the valve stem aperture in response to the sensed configuration of the wheel.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of the provisional patent application 60/453,262 for a VALVE STEM INSTALLATION SYSTEM AND METHOD OF INSTALLING VALVE STEM, filed on Mar. 10, 2003, and claims the benefit of the provisional patent application 60/460,153 for a TIRE PRESSURE MONITORING VALVE STEM INSTALLATION SYSTEM AND METHOD OF INSTALLING TIRE PRESSURE MONITORING VALVE STEM, filed Apr. 3, 2003, which are hereby incorporated by reference in their entireties. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The subject invention relates to the assembly of wheels, and more particularly to an apparatus and method for locating a valve stem aperture in a wheel and mounting the valve stem to the wheel.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the past, a valve stem was manually mounted to a wheel with a stem-inserting tool. Such manual processes are expensive because of the labor and time involved. In addition, operations performed manually are subject to a relatively greater frequency of processing errors in comparison to robot-performed processes.  
         [0004]     Several prior art patents disclose processes for mounting a valve stem to a wheel with programmable machines. For example, U.S. Pat. No. 6,481,083 teaches a valve stem assembly line that includes an input conveyor to supply wheels, a locator station positioned at the end of the input conveyor to locate the valve stem aperture defined by the wheel, and a robotic manipulator to grasp the wheel in the locator station and to move the wheel to the mounting station where a valve stem is inserted. U.S. Pat. No. 6,026,552 teaches a spinning device to spin the wheel, an optical sensor to locate the valve stem aperture while the wheel is spinning, and press fitting device that can slide relative to a wheel and insert a valve stem after the valve stem aperture has been located. U.S. Pat. No. 5,940,960 teaches and automatic valve stemming apparatus including a spinning device to spin the wheel, an optical sensor to locate the valve stem aperture, and a valve stem insertion tool to insert a valve stem after the valve stem aperture has been located.  
         [0005]     One of the areas of continuous development and research is the pursuit of flexible systems operable to receive and process several differently configured rims. Another area is the pursuit of less costly valve stem insertion devices. Costliness can be defined by the capital investment required for putting the valve stem insertion system on the factory floor as well as the operating cost associated with the system. In pursuit of these goals, it would be desirable to develop a valve stem insertion system having improved flexibility, cost and efficiency.  
       BRIEF SUMMARY OF INVENTION  
       [0006]     The invention provides an apparatus and method for locating a valve stem aperture in a wheel and inserting the valve stem in the valve stem aperture. The valve stem and the valve stem aperture are moved relative to one another at a predetermined relative speed in a first rotational direction along a curved path of the wheel perimeter to align the valve stem with the valve stem aperture. The valve stem is supported with a pin and the pin is moved around the wheel with a robotic apparatus. A first sensor locates the valve stem aperture when the valve stem and the valve stem aperture are a first angular distance from one another along the curved path. In response to the first sensor locating the valve stem aperture, the relative speed of movement between the valve stem and the valve stem aperture is reduced. A second sensor locates the valve stem aperture when the valve stem and the valve stem aperture are a first angular distance from one another along the curved path.  
         [0007]     One of the advantages of the present invention is that processing time for inserting the valve stem in the valve stem aperture is reduced. Specifically, the relative movement between the valve stem and the valve stem aperture can be maximized prior to the locating step and the first and second sensor can be spaced from one another to accommodate the braking capacity of the system. In other words, the invention substantially eliminates time delays associated with confirming the location of the valve stem aperture that are common in prior art locating systems. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:  
         [0009]      FIG. 1  is an overhead schematic view of a valve stem installation system according to the exemplary embodiment of the invention;  
         [0010]      FIG. 2  is a side view of an identification station for the valve stem installation system shown in  FIG. 1  for identifying an individual wheel from a plurality of differently configured wheels;  
         [0011]      FIG. 3  is a top view of a portion of the valve stem installation system shown in  FIGS. 1 and 2  showing pin stop assemblies positioned along a roller conveyor for preventing movement of a wheel along the roller conveyor;  
         [0012]      FIG. 4  is a partial cross-sectional view of the valve stem installation system shown in  FIGS. 1-3  showing a positioning device for positioning a wheel and a locating and inserting assembly for inserting a valve stem in a valve stem aperture defined by a wheel;  
         [0013]     FIGS.  5  is a partial cross-sectional view of the valve stem installation system shown in  FIGS. 1-4  and offset ninety degrees from the view in  FIG. 4 , showing the positioning device and the locating and inserting assembly;  
         [0014]      FIG. 6  is a side view of the valve stem installation system shown in  FIG. 1  with additional structural details; and  
         [0015]      FIG. 7-10  are perspective views illustrating a sequence of locating a valve stem aperture and inserting a valve stem in the valve stem aperture. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     Referring now to  FIG. 1 , the present invention provides a method and apparatus  10  for inserting a valve stem in a valve stem aperture defined by a wheel. The apparatus  10  includes a conveyor  12  for moving wheels  14  past a robotic apparatus  16 . Valve stems are inserted in the valve stem aperture defined by the wheel  14  by the robotic apparatus  16 . Wheels  14  can be received at a beginning  18  of the conveyor  12  and move in a direction  20  to an end  22  of the conveyor  12 .  
         [0017]     Referring now to  FIGS. 1 and 2 , during movement of the wheel  14  between the beginning  18  and end  22  of the conveyor  12 , the wheel  14  passes through an identification station  24 . The identification station  24  can include a camera  26  for identifying the wheel  14  from a plurality of differently configured wheels. When a wheel  14  moves within the visual range of the camera  26 , the camera  26  communicates an image of the wheel  14  to a controller  28 . The image includes structural features of the wheel  14  including the position of the valve stem aperture. The controller  28  compares the image received from the camera  26  with a plurality of images stored in memory. The images in memory correspond to all of the differently configured wheels that can pass through the identification station  24 . Each of the images stored in memory is associated with structural characteristics and physical dimensions of a corresponding wheel  14 . The controller  28  controls processing steps performed downstream of the identification station  24  based, at least in part, on the physical dimensions of the wheel  14  identified from the image received from the camera  26 .  
         [0018]     Referring now to  FIGS. 1 and 3 , the conveyor  12  includes clutch-assisted, driven rollers  30  to move the wheel  14  from the identification station  24  to a first position  32  along the conveyor  12 . The wheel  14  can move along the conveyor  12  in the direction  20  until the wheel  14  engages a pair of pin stops  34 ,  36 . The conveyor  12  includes undriven rollers  38  between the first position  32  and the pin stops  34 ,  36 . The pin stops  34 ,  36  are actuated between an extended position above the conveyor  12  and a retracted position below the conveyor  12  to stop movement of the wheel  14  in the direction  20  along the conveyor  12 . The pin stops  34 ,  36  are controlled in movement by the controller  28 . Sensors (not shown) are positioned along the conveyor  12  to sense the position of the wheel  14  along the conveyor  12  and communicate the sensed position of the wheel  14  to the controller  28 .  
         [0019]     Referring now to  FIGS. 1 and 3 - 5 , a positioning device  40  is disposed along the conveyor  12  adjacent the robotic apparatus  16 . The positioning device  40  includes a first positioning mechanism  42  and a second positioning mechanism  44 . The positioning mechanisms  42 ,  44  are substantially similar with respect to one another and are disposed along the conveyor  12  between the first position  32  and a second position  46 . The first positioning mechanism  42  includes a housing  47 . The housing  47  defines apertures  48 ,  50  and  52  for receiving guide tracks  54 ,  56  and  58 , respectively as best seen in  FIGS. 4 and 5 . The guide tracks  54 ,  56  and  58  guide movement of the housing  48  along the conveyor  12 . A metal piston (not shown) is disposed internally of the guide track  58  and cooperate magnetically with the housing  48 . For example, the housing  48  houses a magnet to attract the metal piston in the guide track  58 . The piston is moved by selectively directing pressurized air to opposite sides of the piston in the guide track  58 . The housing  48  moves in response to movement of the piston. The second positioning mechanism  44  is structured similarly and function similarly as the first positioning mechanism  42 . For example, the second positioning mechanism  44  includes a housing  60  defining apertures  62 ,  64 ,  66  for receiving guide tracks  68 ,  70 ,  72 , respectively, as best shown in  FIGS. 4 and 5 . A metal piston is disposed internally of the guide track  72  and cooperates with the housing  60  to move the housing  60  along the conveyor  12 . Movement of the pistons inside the tracks  58 ,  72  are controlled by the controller  28 .  
         [0020]     Referring now to  FIGS. 3-5 , the first positioning mechanism  42  includes an engaging device  74  for engaging and moving the wheel  14  along the conveyor  12 . The engaging device  74  is connected to the housing  47  and includes an arm  76  rotatable about an axis  78 . An engaging portion  80  is disposed at the end of the arm  76  and is shaped to correspond to the shape of the wheel  14 . During movement of the housing  47  along the conveyor  12  in the direction  20 , the arm  76  is located in a first position shown in solid line in  FIG. 4 . After the housing  47  has moved a predetermined distance along the conveyor  12  in the direction  20 , the arm  76  is moved to a second position shown in phantom in  FIG. 4 . The arm  76  is moved to the second position to prevent the engaging portion  80  from interfering with movement of a following wheel moving along the conveyor  12  and is therefore positioned below the conveyor  12 . The positioning device  42  moves the wheel  14  along the conveyor  12  to a position along the conveyor  12  at which the second positioning mechanism  44  can engage the wheel  14 . The second positioning mechanism  44  includes an engaging device  82  structured similarly and functioning similarly as the first engaging device  74 . For example, the engaging device  82  includes an arm  84  rotatable about an axis  86  and an engaging portion  88  positioned at the end of the arm  84 . The second positioning mechanism  44  moves the wheel  14  away from the robotic apparatus  16  after a valve stem has been inserted in the valve stem aperture defined by the wheel, a process described in greater detail below. Once the second positioning mechanism  44  moves the wheel  14 , the first positioning mechanism  42  moves a second wheel  14  along the conveyor  12  until the second wheel  14  engages a second pair of pin stops  90 ,  92 .  
         [0021]     Referring now to  FIGS. 1 and 6 , after the wheel  14  is positioned adjacent the robotic apparatus  16  by the positioning device  40 , the robotic apparatus  16  inserts a valve stem in the valve stem aperture defined by the wheel  14 . The robotic apparatus  16  moves a locating and inserting assembly  90  around the wheel  14 , shown schematically in  FIGS. 1 and 6 . The assembly  90  receives valve stems from one or more valve stem feeding stations  92  disposed along the conveyor  12 . Each station  92  includes a hopper  94  for receiving valve stems and a sorting device  96  for sorting the valve stems and arranging the valve stems in an orientation to be received by the assembly  90 . The different valve stem feeding stations  92  sort different configurations of valve stems. A nut runner  98  is attached to the assembly  90  to insert nuts on valve stems that require nuts. The nut runner  98  receives nuts from a nut feeding station  100  through a conduit  102 . The station  100  can be disposed along the conveyor  12 .  
         [0022]     Referring now to  FIGS. 4 and 5 , the assembly  90  includes a locating device  104  and a stem inserting device  106 . The locating device  104  includes a pair of light emitters, such as light emitter  108 , and a pair of light receivers, such as light receiver  110 . The inserting device  106  includes a valve stem holding pin  112 , a support plate  114 , and a moving device  116  for moving the holding pin  112  and the support plate  114  relative to one another.  
         [0023]     The method for locating the valve stem aperture in the wheel is shown schematically in  FIGS. 7-10 . In  FIG. 7 , the embodiment of the assembly  90   a  includes a pair of light emitters  108   a  and  108   b , as well as a pair of light receivers  110   a  and  110   b . The assembly also includes a support plate  114   a  and a valve stem holding pin  112   a . The assembly  90   a  is moved around the wheel  14  in the direction  122 . The light emitters  108   a ,  108   b  are disposed on an opposite side of a lip  120  of the wheel  14  with respect to the light receivers  110   a ,  110   b . The valve stem aperture  118  is defined in the lip  120 . The assembly  90   a  is moved in the direction  122  and the light receiver  110   a  receives light from the light emitter  108   a  through the valve stem aperture  118 . The assembly  90   a  moves in the direction  122  at a predetermined angular velocity and is slowed by the controller  28  in response to the communication between the light emitter  108   a  and the light receiver  110   a  through the valve stem aperture  118 .  
         [0024]     Referring now to  FIG. 8 , the assembly  90   a  is stopped after passing the valve stem aperture  118 . Due to the delay between sensing the light by the first receiver  110   a , signaling the controller  28 , the assembly  90   a  typically passes the aperture  118  prior to stopping the robot  16 . The assembly  90   a  is moved in the direction  124  until the light receiver  110   b  receives light from the light emitter  108   b  through the valve stem aperture  118 , shown in  FIG. 9 . In response to the communication between the light receiver  110   b  and the light emitter  108   b  through the valve stem aperture  118 , the assembly  90   a  is moved in the direction  122  until the valve stem holding pin  112  is aligned with the aperture  118  and the valve stem is then inserted, as shown in  FIG. 10 . The assembly  90   a  moves much faster in the direction of arrow  122  than in the direction of arrow  124  because more distance is typically traveled to first locate the aperture  118 . Once the aperture  118  is located, the assembly moves at a slower rate in the direction of arrow  124  to determine a more precise location of the aperture  118  prior to aligning the stem holding pin  112   a  with the aperture  118 .  
         [0025]     Referring now to  FIGS. 4 and 5 , the valve stem is inserted in the valve stem aperture  118   a  defined in the lip  120   a  of the wheel  14  by engaging the moving device to move the valve stem holding pin  112  relative to the support plate  114 . The moving device  116  includes a plate  126  attached to the robotic apparatus  16 . The moving device  116  also includes a cylinder  128  attached to the plate  126  and a rod  130  extendable and retractable with respect to the cylinder  128 . The valve stem holding pin  112  is fixedly associated with the end of the rod  130  and the support plate  114  is rotatably associated with the cylinder  128 . After the valve stem aperture  118  has been located the robotic apparatus moves the support plate  114  to engage the lip  120   a  of the wheel  14 . The rod  130  is retracted in the cylinder  128 , moving the valve stem holding pin  112  through the aperture  118   a . The rod  130  is extended to remove the valve stem holding pin  112  from the aperture  118   a , leaving the valve stem in the valve stem aperture  118   a.    
         [0026]     Referring now to  FIGS. 3 and 4 , after the valve stem has been inserted in the valve stem aperture  118   a , the second positioning mechanism  44  moves the wheel with the inserted valve stem along the conveyor  12  past the retracted pin stops  90 - 92 . The wheel  14  now continues along the conveyor  12  for further processing operations.  
         [0027]     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims. These antecedent recitations should be interpreted to cover any combination in which the incentive novelty exercises its utility. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.