Abstract:
A method and apparatus for cleaning a tire mold with frozen CO 2  cleaning material wherein a portable frame is positioned on a bottom mold of a tire press and has a rotatable frame on which a nozzle support is mounted for swivel action to clean the upper mold half and the lower mold half as the nozzle support is moved radially and circumferentially of the tire mold.

Description:
TECHNICAL FIELD 
     This invention relates to tire mold cleaning and especially to automated sidewall cleaning of the tire mold halves without removing the mold halves from the tire press. 
     BACKGROUND ART 
     Tire mold cleaning apparatus such as that shown in U.S. Pat. No. 3,905,155 have been designed for cleaning a tire mold while in the press with an abrasive such as glass beads. One of the problems with this type of cleaner is the removal of the spent abrasive from the tire mold. It has been proposed to use frozen CO2 as the abrasive which leaves no residue. With the CO2 cleaning a high noise level is created requiring a sound curtain to be placed around the mold. Enclosures for the mold which are soundproof have been proposed, however, this requires removing the mold from the tire press. The mold cleaner also needs to clean the upper and lower mold halves without removing either of these mold halves from the tire press. This creates a problem in adapting the cleaning apparatus to maintain the spray nozzle at a constant distance from the mold surface while adjusting the position of the spray nozzle to different spacing between the mold halves depending upon the size of the tire press. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a portable tire mold cleaning apparatus for cleaning the sidewall forming surface of the mold with frozen CO2 without removing the mold from the tire press. The mold cleaning apparatus may be transported to the tire press and quickly set up in the breech ring of the press. The spray nozzle is rotated and moved radially as well as axially to follow the contour of the mold. The nozzle is mounted for rotation on a horizontal shaft and can be swiveled from a down position for cleaning the lower mold half to an upper position for cleaning the upper mold half. 
     In accordance with one aspect of the invention there is provided a cleaning apparatus for cleaning a tire mold mounted in a tire press, the tire press having an upper mold half positioned over a lower mold half and movable vertically to open and close the mold characterized by: 
     (a) a supporting frame for mounting over said lower mold half and under the upper mold half; 
     (b) a rotatable frame mounted on the supporting frame for rotation about a horizontal axis; 
     (c) a nozzle for spraying a cleaning material on mold surfaces of the upper mold half and the lower mold half mounted on a control arm supported on the rotatable frame; 
     (d) means to rotate the rotatable frame about the horizontal axis to move the control arm from a down position for spraying the cleaning material on the lower mold half to an up position for spraying the cleaning material on the upper mold half; and, 
     (e) means to traverse the control arm circumferentially of the tire mold about a vertical mold axis with the rotatable frame in the down position and in the up position. 
     In accordance with another aspect of the invention, there is provided a method of cleaning a tire mold having an upper mold half positioned over a lower mold half and movable vertically to open and close said mold with a portable cleaning apparatus having a supporting frame, a rotatable frame mounted on the supporting frame, a nozzle for spraying cleaning material mounted on a control arm supported on the rotatable frame and in communication with a source of cleaning material characterized by the steps of: 
     (a) mounting the supporting frame over the lower mold half; 
     (b) rotating the rotatable frame to a position with the control arm in an up position wherein the nozzle in directed at a mold surface of the upper mold half; 
     (c) communicating cleaning material to a nozzle to project the material against the mold surface of the upper mold half; 
     (d) traversing the nozzle circumferentially of the upper mold half on the control arm for cleaning the mold surface of the upper mold half; 
     (e) rotating the rotatable frame to a position with the control arm in a down position wherein the nozzle is directed at a mold surface of the lower mold half; 
     (f) traversing the nozzle circumferentially of the lower mold half on the control arm for cleaning the mold surface of the lower mold half; and, 
     (g) removing the supporting frame from the lower mold half. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the portable cleaning apparatus embodying the invention before mounting in a tire press. 
     FIG. 2 is a front elevation of the apparatus of FIG. 1 mounted in a tire press taken along line  2 — 2  in FIG. 1 showing the nozzle in position for cleaning the lower mold half with parts broken away to show the nozzle. 
     FIG. 3 is a side view of the apparatus of FIG. 1 taken along line  3 — 3  in FIG. 1 showing the nozzle in position for cleaning the lower mold half shown in cross section and with parts broken away. 
     FIG. 4 is a side view like FIG. 3 showing the nozzle in position for cleaning the upper mold half which is shown in cross section. The position of the sound curtain is also shown in dotted lines 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a portable mold cleaning apparatus  10  is shown prior to mounting in a tire press  12 . In FIG. 2, the apparatus  10  is shown mounted in a lower mold  16 . The apparatus  10  has a supporting frame  18  with a cylindrical rolled angle iron base  20 , having a diameter for seating in a press breech ring  21 . Mounted on the base  20  are adjustable stabilizer legs  22  and side leg assemblies  23 . Pillow block bearings  24  and  26  are supported on the side leg assemblies  23  and ratchets  28  and  30  are provided for adjusting the height of the frame  18 . A shaft  36  extends through the bearings  24  and  26  from one side of the lower mold half  16  to a rotatable frame  40  and then to the other side where a crank  38  is mounted for tuning the shaft. The rotatable frame  40  supports a frozen CO2 cleaning unit  42 . 
     Referring to FIGS. 2,  3  and  4 , a manifold  44  is mounted on the rotatable frame  40 . The upper mold half  14  is positioned directly over the lower mold half  16 . A hub  46  is rotatably mounted on the manifold  44  and connected to a pulley  48  which is driven by a belt  50  trained around a pulley  51  having a shaft driven by a motor  52  which may be mounted on the rotatable, frame  40 . 
     A supporting arm  59  is mounted on the hub  46  and supports a stabilizer bracket  60  having guide rollers  62  for engaging the sides of slot  64  in a control arm  66  which supports a nozzle  68 . An upper end  70  of the control arm  66  has a cam roller  72  rotatably supported in a cam slot  74  of a depth gauge  76  fastened to the supporting arm  59 . 
     A rodless cylinder  78  is mounted on the supporting arm  59  and has a piston member  80  connected to the stabilizer bracket  60  for moving the stabilizer bracket and the control arm  66  in a radial direction across the mold surface so that the cam slot  74  and the cam roller  72  control the movement of the nozzle  68  at positions spaced from the mold surface and which conform with the contour of a mold surface  81  of the lower mold half  16  and the contour of a mold surface  85  of the upper mold half  14 . 
     In addition to controlling the position of the nozzle  68  across the width of the mold cavity  81  in the lower mold half  16 , the position of the nozzle circumferentially of the mold is provided by the motor  52  which rotates the drive pulley  51 , causing the belt  50  to rotate the pulley  48  and traverse the nozzle  68  around the circumference of the lower mold half  16 . A rotary union  84  may be mounted on the hub  46  and supports a connecting hose  87  in communication with a source of cleaning material such as frozen CO2 . Bearings  89  and  90  at the ends of the hub  46  permit rotation of the hub relative to the manifold  44  and the rotary union  84 . 
     In operation, as shown in FIG. 4, the cleaning process begins at the outside diameter of an upper mold half  14  of the press  12 . The upper mold cavity may then be cleaned by projecting the CO2 and air through the nozzle  68 , controlling the rotation of the nozzle by regulating the speed of the DC motor  52  and regulating the movement of the nozzle  68  across the mold cavity  21  by controlling the movement of the rodless cylinder  78 . After the nozzle  68  makes one revolution, it makes contact with a proximity switch, which activates the rodless cylinder  78  causing the nozzle  68  to move inwardly approximately 0.46 inches (1.17 cm). When the nozzle  68  moves inwardly, it follows the cam slot  74 , which is contoured to the shape of the mold cavity  85 . This maintains equal pressure and nozzle spray width on the surface of the mold cavity  85  at all times. When the nozzle  68  reaches the inside diameter of the upper mold half  14  it trips another proximity switch which ends the cycle. At this point, the nozzle  68  will no longer be indexed inwardly; however, it will continue to revolve until the motor  52  is turned off. The purpose of keeping the motor  52  running is to allow the CO2 lines to be blown clear, and avoid projecting frozen CO2 on one spot. Suitable controls may be provided to regulate the speed of the motor  52  for rotating the hub  46  at a desired speed. These controls may also be coordinated is with the controls for the rodless cylinder  78  to provide the desired travel of the nozzle  68  radially across the lower mold surface  81  of the lower mold half  16  and the mold surface of the upper mold cavity  85 . Once the cycle is completed and the upper mold half  14  has been cleaned, the crank  38  may be rotated causing the unit supporting frame  18  to be revolved and the nozzle  68  to be aligned with a lower mold surface  81  in the lower mold half  16  as shown in FIGS. 2 and 3. The operation may then be repeated to clean the lower mold surface  81 . 
     The motor  52  is a variable speed DC motor, whereby the operator has the ability to slow down the speed of rotation of hub  46  which is desirable because the cleaning is more efficient at slower speeds. 
     In order to provide air for cleaning and also provide air for the rodless cylinder  78  an air line  86  in communication with a source of air under pressure is connected to the manifold  44 . A second flexible supply line  87  in communication with a supply of frozen CO2 gas under pressure is connected to the manifold  44 . A supply line  91  is provided from the manifold  44  to the nozzle  68 . 
     Suitable controls may be provided to regulate the speed of the motor  52  for rotating the hub  46  at a desired speed. These controls may also be coordinated with the controls for the rodless cylinder  78  to provide the desired travel of the nozzle  68  radially across the mold surface  81  of the lower mold half  16  and mold surface of the upper mold cavity  85 . 
     The apparatus  10  is placed in the lower mold  16  with the angle iron base  20  seated in the press breech ring  21  by a fork lift  92  as shown in dotted lines in FIG.  1 . The upper mold half  14  is positioned directly over the lower mold half  16 . The upper mold cavity  85  may then be cleaned by projecting the CO2 and air through the nozzle  68 , controlling the rotation of the nozzle by regulating the speed of the DC motor  52  and regulating the movement of the nozzle  68  across the mold cavity  21  by controlling the movement of the rodless cylinder  78 . The crank  38  is then locked in position and the rotation of the nozzle  68  is controlled by regulating the speed of the motor  52  for traversing circumferentially around the lower mold cavity  21 , and movement radially of the nozzle across the lower mold cavity is controlled by the rodless cylinder  78 . Then the upper mold  14  can be moved away from the lower mold  16  and from the CO2 cleaning unit  42 . The CO2 cleaning unit  42  may then be lifted out of the lower mold  16  by the forklift  92  and moved to another mold in another press without requiring any alteration of the tire presses. As shown in FIG. 4, a sound curtain  94  is positioned around the tire mold and mold cleaning apparatus.