Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C3/00—Abrasive blasting machines or devices; Plants
  • B24C3/32—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks
  • B24C3/325—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks for internal surfaces, e.g. of tubes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
  • B24C1/003—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods using material which dissolves or changes phase after the treatment, e.g. ice, CO2
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C3/00—Abrasive blasting machines or devices; Plants
  • B24C3/08—Abrasive blasting machines or devices; Plants essentially adapted for abrasive blasting of travelling stock or travelling workpieces
  • B24C3/083—Transfer or feeding devices; Accessories therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C3/00—Abrasive blasting machines or devices; Plants
  • B24C3/18—Abrasive blasting machines or devices; Plants essentially provided with means for moving workpieces into different working positions
  • B24C3/20—Abrasive blasting machines or devices; Plants essentially provided with means for moving workpieces into different working positions the work being supported by turntables
  • B24C3/22—Apparatus using nozzles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/70—Maintenance
  • B29C33/72—Cleaning
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D30/00—Producing pneumatic or solid tyres or parts thereof
  • B29D30/06—Pneumatic tyres or parts thereof (e.g. produced by casting, moulding, compression moulding, injection moulding, centrifugal casting)
  • B29D30/0601—Vulcanising tyres; Vulcanising presses for tyres
  • B29D30/0662—Accessories, details or auxiliary operations
  • B29D2030/0663—Mould maintenance, e.g. cleaning, washing, repairing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2030/00—Pneumatic or solid tyres or parts thereof

Definitions

• This invention pertains to the art of methods and apparatuses for cleaning tire molds, and more specifically to methods and apparatuses for cleaning tire molds using pellets of frozen carbon dioxide, hereafter referred to as CO 2 .
• Background Art
• blasting agent such as sand or glass beads. After the blasting agent had been used to clean a tire mold, it had to be recovered or removed. The recovery of the blasting agent increased the time necessary to clean tire molds and caused a contamination problem in the plant.
• the present invention contemplates a new and improved tire mold cleaning method and apparatus which is simple in design, effective in use, and overcomes the foregoing difficulties and others while providing better and more advantageous overall results. Disclosure of Invention
• a new and improved method and apparatus for cleaning a mold, particularly a tire mold which uses CO 2 pellets to clean the tire mold.
• an apparatus for cleaning a tire mold with CO 2 pellets directed against the molding surfaces of the tire mold includes a sound-proof insulated enclosure for the tire mold, a rotatable support for positioning and rotating the tire mold in the enclosure, a robot in the enclosure that has an arm moveable to select cleaning positions over the molding surfaces of the tire mold, a nozzle mounted on the arm and in communication with a source of CO 2 pellets, a robot control apparatus for rotating the arm to position the nozzle over the molding surfaces to direct the CO 2 pellets against the molding surfaces in a direction substantially perpendicul ⁇ ir to the molding surfaces at different positions axially of the tire mold, and a power apparatus for rotating the rotatable support while the CO 2 pellets are directed against the molding surfaces.
• a method of • cleaning the tire mold with CO 2 pellets directed against the molding surfaces of the tire mold includes the steps of supporting the tire mold on a rotatable support in a sound-proof insulated enclosure, and communicating CO 2 pellets to the molding surfaces from a pellet mixer by air pressure to a nozzle adjacent the molding surfaces and moving the nozzle axially within the tire mold while rotating the tire mold about an axis on the rotatable support to traverse the molding surfaces.
• One advantage of the present invention is that the cleaning apparatus is completely automatic.
• Another advantage of the present invention is that the CO 2 pellets are non-abrasive and do not damage the tire mold.
• Another advantage of the present invention is that the CO 2 pellets melt and evaporate after contacting the tire mold, thereby eliminating the need to recover used blasting agents.
• Another advantage of the present invention is that the frozen CO 2 pellets also clean microvents in the tire molds, thereby eliminating the need to drill the microvents manually.
• Figure 1 is a schematic view of a robotic CO 2 cleaning apparatus
• Figure 2 is a detailed view of a spray nozzle with a closed flow regulator and safety shut off;
• FIG 3 is a detailed view of the spray nozzle like Figure 2 with an open flow regulator
• Figure 4 is a plan view of a preferred embodiment of a robotic CO 2 cleaning apparatus
• Figure 5 is a front election of the robotic CO 2 cleaning apparatus of Figure 4.
• FIG. 6 is an enlarged fragmentary view of one of the rotary tables and the spray nozzle as used with robotic CO 2 cleaning apparatus of Figures 3, 4, and 5. Detailed Description of the Invention
• Figure 1 shows a schematic view of a robotic CO 2 cleaning apparatus 10.
• a segmented tire mold 16 is placed onto an entry conveyor 22 by a hoist 28.
• the tire mold 16 is heated with steam so that the tire mold placed on the entry conveyor 22 is heated to a temperature of approximately 350°F (177°C).
• the tire mold 16 is heated to near the curing temperature of the tire to facilitate the rapid removal of material from the tire mold 16 during the cleaning process.
• the entry conveyor 22 conveys the tire mold 16 through an opening 32 into an enclosure 34 that is preferably sound-proof and insulated.
• the opening 32 may include a door (not shown) that closes the opening when the cleaning apparatus 10 is in operation.
• the enclosure 34 is preferably sound-proof to reduce noise that may be objectionable to employees working around the cleaning apparatus 10.
• the enclosure 34 is preferably insulated to maintain the temperature of the tire mold 16 as near the tire curing temperature as is feasible.
• the tire mold 16 is transferred to a rotary table 40 and cleaned by a robot 46 directing frozen CO 2 pellets against the mold surfaces.
• CO 2 pellets preferably have diameters between 0.04 inch and 0.12 inch and temperatures of about -80°F (-62°C). Fro ⁇ n CO 2 is preferred because such pellets are non-abrasive, thereby extending the life of the tire mold 16 and improving the appearance of the tire produced by the tire mold. Additionally, the frozen CO 2 evaporates on contact with the tire mold 16, producing a pressurized gas that cleans out the microvents of the tire mold. Also, since the CO 2 pellets evaporate on contact with the tire mold half 16, housekeeping is improved because no blasting agents are deposited on the other equipment or on the floor..
• the segmented tire mold 16 need not be disassembled and is conveyed onto a rotary table 40 rotatable about the axis and controlled by a servomotor (not shown).
• the rotary table 40 rotates the tire mold 16 past a spray nozzle 52 of a robot 46.
• the spray nozzle 52 is attached to the end of the robot 46.
• the robot 46 is multidirectional, preferably being a six axis robot, so that the spray nozzle 52 may be adjusted to clean an entire tire mold 16.
• the spray nozzle 52 is preferably adjusted by the robot 46 to aim a stream of frozen CO 2 pellets in a direction normal to the surface of the tire mold 16 that is being cleaned.
• the speed at which the rotary table 40 rotates is adjustable as is the robot 46 positioning of the spray nozzle 52 to optimize the cleaning action of the cleaning apparatus 10.
• the rotational speed of the rotary table 40 and the position of the spray nozzle 52 at the end of the robot 46 are preferably regulated by a fully programmable robot controller 58.
• a safety shut off 72 is interposed between the spray nozzle 52 and the robot to shut down the apparatus if the spray nozzle engages the mold 16 during the cleaning.
• Figure 2 shows a close-up view of the spray nozzle 52.
• the spray nozzle 52 is preferably curved slightly to enable the robot 46 to position the spray nozzle to clean a variety of different curved surfaces of the tire mold 16.
• the end of the spray nozzle 52 has a flow regulator 64 that regulates the flow of frozen CO 2 pellets through the end of the spray nozzle.
• the flow regulator 64 may be closed completely to prohibit the flow of frozen CO 2 pellets, or, as shown in Figure 3, the flow regulator may be opened up to a diameter 70 of 1.0 inch to increase the flow of frozen CO 2 pellets.
• Liquid nitrogen (N 2 ) may be injected into the air delivery system to super cool the frozen CO 2 pellets to ensure that the pellets do not disintegrate or evaporate before they are delivered as a blasting agent.
• a mold pusher 76 pushes the tire mold 16 off the rotary table 40 and onto an exit conveyor 82.
• the exit conveyor 82 conveys the tire mold 16 out of the enclosure 34 through a second opening 88 in the enclosure.
• the second opening 88 may have a door (not shown) which closes the opening when the cleaning apparatus is in operation.
• the tire mold 16 is then transferred to a staging conveyor 94 where it awaits transport back into the tire production process.
• a tire mold 16 may be cleaned in approximately ten minutes using the cleaning apparatus 10.
• FIGs 4-6 show a preferred embodiment of the invention.
• the robotic CO 2 cleaning apparatus 10 is preferably enclosed in a special enclosure 100 that has two doors 106, 108.
• the doors 106, 108 open to allow a tire mold 16 to be placed in the enclosure 100, and then the doors are closed before the robotic CO 2 cleaning apparatus is activated.
• the doors 106, 108 preferably have windows to allow an operator to see the tire mold 16 as it is cleaned.
• this preferred embodiment features two rotary tables
• Each rotary table 114,116 located on opposite sides of the robot 46.
• Each rotary table 114,116 has a centering apparatus that consists of preferably three radially movable centering guide members 122 that operate to center a tire mold 16 or mold half on each rotary table about, an axis of rotation of the table after the tire mold half is placed on each of the rotary tables by the hoist 28.
• each tire mold 16 to be cleaned is heated to approximately 350°F (177°C) to optimize the cleaning procedure.
• the rotary tables 114, 116 rotate each tire mold 16 as the robot 46 positions the spray nozzle 52 normal to the mold surface of one of the tire molds to be cleaned, as illustrated in Figure 6.
• the spray nozzle 52 shown in solid lines illustrates the position of the spray nozzle for cleaning the sidewall surface 128 of the tire mold 16.
• the spray nozzle 52a shown in dotted lines shows the position of the spray nozzle for cleaning the tread surface 130 of the tire mold 16.
• the spray nozzle 52b shown in dotted lines shows the position of the spray nozzle for cleaning the bead surface 132 of the tire mold half 16.
• the rotary tables 114,116 rotate each tire mold 16 about an axis of the tables past the spray nozzle 52 for a specified number of rotations to ensure thorough cleaning.
• the number of rotations may be controlled by a robot controller (not shown) programmed to meet mold cleaning specifications, or an operator may manually control the cleaning of a tire mold 16 by controlling the number of rotations of one of the rotary tables 114, 116 or the positioning of the robot 46.
• the rotary tables 114,116 rotate from 2 rpm to 4 rpm for ten revolutions to clean each of the tread surfaces

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22255642

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (23)

Family Cites Families (9)

• 1996
  • 1996-08-22 JP JP10510684A patent/JP2000516861A/ja active Pending
  • 1996-08-22 CA CA002262688A patent/CA2262688A1/en not_active Abandoned
  • 1996-08-22 BR BR9612734A patent/BR9612734A/pt active Search and Examination
  • 1996-08-22 EP EP96928964A patent/EP0921905A1/de not_active Withdrawn
  • 1996-08-22 WO PCT/US1996/013521 patent/WO1998007548A1/en not_active Application Discontinuation
  • 1996-08-22 AU AU68534/96A patent/AU6853496A/en not_active Abandoned

Non-Patent Citations (1)

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