Abstract:
The invention relates to an apparatus for the cleaning and/or coating of a mold surface of a mold. The apparatus has a frame which can be placed onto the mold and in which a handling device is movable along a predetermined track in such a way that at least one cleaning or coating unit provided on the handling unit, of which the relative position is adjustable relative to the mold surface, is moved past the mold surface at a predetermined spacing to carry out the cleaning or coating process. A drive means is provided for the adjustment of the relative position of the cleaning or coating unit and can be coupled to the handling device, but is decoupled from the handling device during the movement thereof.

Description:
The invention relates to an apparatus for the cleaning and/or coating of a mold surface of a mold, in particular of the mold surface of a vulcanization mold for the manufacture of tires, comprising a frame which can be placed onto the mold and in which a handling device is movable along a predetermined track in such a way that at least one cleaning or coating unit is provided on the handling unit of which the relative position is adjustable relative to the mold surface, is moved past the mold surface at a predetermined spacing for the cleaning or coating, and further comprising a drive means for the adjustment of the position of the cleaning or coating unit. Furthermore, the invention relates to a method for the cleaning and/or coating of a mold surface of a mold. 
     The apparatus and method for the cleaning of the mold surface of a mold, in particular the mold surface of a vulcanization mold for the manufacture of tires, is known from DE 197 12 513 A1. In this apparatus a frame in which a five-axes robot is movable as a handling unit along a circular track is inserted between the part molds of the mold which can be moved apart. A nozzle for dry ice pellets is provided at the free end of the robot, and the relative position of the nozzle relative to the mold surface can be set with the aid of the robot. After the relative position has been set, the total robot, which is secured on a rotatable ring, is moved circularly, with the dry ice pellets which emerge from the nozzle cleaning the mold surface. 
     In this known apparatus the problem exists that as a result of the use of the robot, which takes up a lot of constructional volume as a consequence of its design, the frame must be of correspondingly large dimensions, so that the mold parts mold must be moved correspondingly far apart. Furthermore, the programming of the five-axis robot is very time and cost intensive as a result of the complex movements of the different axes, which must be coordinated with one another. A further problem in the known apparatus resides in the fact that it is exposed to high temperatures when used for the cleaning of vulcanization molds since the molds are cleaned during the running operation and consequently only cool down a little. This has the consequence that both the sensitive electronics, the drives and also the mechanical bearing points of the robot are exposed to correspondingly high operating temperatures through which their orderly operation can be disturbed. Finally, the drive with which the robot is moved in the frame must be laid out to be correspondingly powerful as a result of the masses which the robot and its drive components have, which have to be moved and braked. It is the object of the invention to so further develop the apparatus and method of the initially named kind that the handling apparatus can be programmed without great effort and an orderly operation of the handling device is possible even at high environmental temperatures. 
     SUMMARY OF THE INVENTION 
     The invention is satisfied by an apparatus having the following features. An apparatus for the cleaning and/or coating of a mold surface of a mold, in particular of the mold surface of a vulcanization mold for the manufacture of tires. The apparatus has a frame which can be placed onto the mold and in which a handling device is movable along a predetermined track in such a way that at least one cleaning or coating unit is provided on the handling device, of which the relative position is adjustable relative to the mold surface. The at least one cleaning or coating units is moved past the mold surface at a predetermined spacing for the cleaning or coating. 
     The apparatus further has a drive means for the adjustment of the position of the cleaning or coating unit, wherein the drive means coupled to the handling device for the adjustment of the relative position of the cleaning or coating unit is decoupled from the handling device, at least during the movement of the handling device along the predetermined track, with the cleaning or coating unit retaining its relative position with respect to the mold surface previously set by the drive device. Furthermore, the object is satisfied by a method having the following features. A method for the coating or cleaning of the mold surface of a mold, in particular of the mold surface of a vulcanization mold for the production of tires, in which a frame is positioned onto the mold, in which the relative position of a cleaning and/or coating unit held on a handling device movable along a predetermined track in the frame is subsequently adjusted with the aid of a drive means and thereafter the handling device is moved along the predetermined track, with the cleaning or coating unit being moved in its adjusted position past the mold surface for the cleaning or coating respectively. The drive means is uncoupled from the handling device after the relative position of the cleaning or coating device has been adjusted. The handling device is then subsequently moved along the predetermined track and is coupled again to the drive means for renewed setting of the relative position of the cleaning or coating unit. 
     In the invention the drive means is decoupled from the handling device during the movement of the handling device, while it is connected to the handling device at least during the adjustment of the cleaning or coating unit. The drive means is consequently not co-moved during the movement of the handling device in the frame, so that the drive which moves the handling device can be made correspondingly small. Furthermore, the constructional space required in the frame for the handling device is smaller in the apparatus of the invention than in the known apparatus, since the drive device which can be decoupled from the handling device need not be directly arranged in the inner space surrounded by the frame. Since the cleaning or coating unit retains its relative position previously set by the drive device with respect to the mold surface, even when the drive means is decoupled, a follow-up regulation of the position of the cleaning or coating unit during the movement of the handling device is not required, so that, on the one hand, the control complexity is smaller and, on the other hand, sensitive control modules and sensors which could be impaired in their manner of operation through the high temperatures, in particular during the cleaning of vulcanization molds, do not have to be provided at the handling device. 
     Further advantageous developments of the invention can be seen from the subsequent description, the drawing and also the subordinate claims. Thus, it is proposed that the handling device should be provided with a braking unit which locks the cleaning or coating unit in its relative position after the adjustment. In this way a situation is achieved in which the relative position of the cleaning or coating unit is also not misadjusted with a jolt-like movement of the handling device. 
     Furthermore, it is proposed that a self-locking positioning unit which is coupled with the drive means for the adjustment should be provided at the handling device, in addition to, or as an alternative to, the locking of the relative position of the cleaning or coating unit. In this embodiment the self-locking of the positioning unit also achieves a situation in which the position of the cleaning or coating unit does not change during the movement of the handling device. 
     In a preferred embodiment of the apparatus the drive means for the adjustment of the cleaning or coating unit is held on a carriage which is movable between a rest position, in which the drive means is spaced from the handling device, and a coupling position, in which the drive means is coupled to the handling device. With the aid of the carriage a rapid coupling on and decoupling of the drive means to or from the handling device is made possible, with the drive means being spaced from the frame when the carriage is moved into its rest position so that it is protected from high temperatures. 
     The handling device preferably has an attachment unit with which it is held on a rotating ring, which is rotatably mounted in the frame about an axis of rotation. During the cleaning or coating the frame is aligned relative to the mold so that the axis of rotation coincides with the axis of symmetry of the mold which is to be cleaned. Through the use of a rotatable ring, the handling device moves on a circular track, so that the handling device is particularly suited for rotationally symmetrical molds in particular, such as are, for example, used in the manufacture of motor vehicle tires. 
     As an alternative it is proposed that the attachment unit of the handling means should be guided in a guide provided at the frame, which forms a closed surrounding contour. In this embodiment the contour can, for example, extend in the shape of an oval, a rectangle or a polygon, so that molds with correspondingly designed mold surfaces can be cleaned or coated. 
     A telescopic arm which is pivotally mounted on the attachment unit is proposed as the handling device, with the pivotal position and length being adjustable with the aid of the drive means and with the cleaning or coating unit being held at the free end of the telescopic arm remote from the attachment unit. Through the use of a telescopic arm, an exact and positionally accurate setting of the position of the cleaning or coating unit can be effected without substantial technical control complexity. 
     In order to enable the most accurate possible alignment of the cleaning or coating unit relative to the mold surface, it is furthermore proposed that the cleaning or coating unit should be pivotally mounted on the handling device, i.e. on the telescopic arm, with the pivotal position being adjustable here with the aid of the drive means. 
     In a particularly preferred embodiment of the apparatus of the invention, a centering unit is additionally provided at the frame with which the frame can be aligned with respect to the mold which is to be cleaned or coated. A centering ring which is, for example, rotatably mounted on the frame, is, for example, suitable as the centering unit, with the centering ring standing in a co-operative connection with at least one lever which is pivotably mounted in the frame, such that, with one turn of the centering ring in a first direction, the lever comes into contact with the mold for alignment and, with a rotation of the centering ring in a second direction opposite to the first direction, the lever is moved away from the frame. With the aid of the centering unit the frame can be aligned in a defined position relative to the mold once it has been placed onto the mold, so that the cleaning or coating unit is moved past the mold surface during movement of the handling device without large fluctuations of the predetermined spacing. 
     Since correspondingly high noise emissions arise, in particular when cleaning the mold with dry ice or laser beams, it is furthermore proposed that the housing should be provided with a sound insulating jacket which at least partly surrounds the range of movement of the handling device. 
     The previously described apparatus can be used for the cleaning of one piece and also multi-piece molds. It is particularly suitable for the cleaning of a mold which is formed from at least two-part molds, with the part molds preferably being moveable apart from one another in an axial direction. For the cleaning or coating, the frame is moved between the part molds that should be moved apart and onto the part mold which is to be cleaned. Furthermore, the part molds can be moved together again after the insertion of the frame, with the frame being lightly clamped between the part molds. In this manner it is possible to clean or coat first the one and subsequently the second part mold in one cleaning or coating process. 
     If the apparatus is used for the cleaning or coating of a vulcanization mold, then it is furthermore proposed that the vulcanization mold should be kept at a temperature in a range of 140 to 175° C., preferably in a range from 155 to 160° C. In this way a situation is achieved in which the vulcanization mold can be directly used again for vulcanization after cleaning or coating, without the mold having to be heated up to its operating temperature again. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following the invention will be explained in more detail with reference to an embodiment and to the drawings, in which are shown: 
     FIG. 1 a perspective illustration of an apparatus in accordance with the invention for the cleaning of a vulcanization mold; 
     FIG. 2 a perspective illustration of the apparatus of FIG. 1 showing only one centering device as provided; 
     FIG. 3 a perspective illustration of the apparatus of FIG. 1 showing only one rotary mounting of the handling device; 
     FIG. 4 a perspective illustration of the apparatus of FIG. 1 in which the handling device mounted on the rotatably journalled rotatable ring is shown in its rest position; 
     FIG. 5 a schematic side view of a braking device for the locking of a threaded spindle of the handling device; 
     FIG. 6 a perspective illustration of the apparatus of FIG. 4 in which the handling device is shown in a working position; and 
     FIG. 7 a perspective illustration of the apparatus of FIG. 1 during the cleaning of the part mold of a vulcanization mold. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows in a perspective illustration an apparatus  10  for the cleaning of molds, in particular of vulcanization molds. The apparatus  10  can also be used with a corresponding change of design for the coating of the molds, with a coating pistol being used in place of a cleaning pistol. The apparatus  10  has a frame  12  and a housing  14  which projects radially outwardly and is secured to the frame  12  and shown at the left in FIG. 1, with which the apparatus  10  can be coupled onto a preferably movable lifting device (not shown). Both the frame  12  and also the housing  14  are surrounded by a sound insulating jacket (not shown), which reduces the noise emissions which arise during cleaning to a level which is bearable for humans. 
     The frame  12  has a support ring  16  shown at the bottom in FIG. 1 and a plurality of identical spacers  18  stand perpendicularly upwardly from the top surface of the support ring in the same direction. The spacers  18  support a bearing ring  20 , which is fixedly screwed to the spacers  18  and the purpose of which will be explained later. A second spacer  22  stands vertically upwardly at each mounting point of the bearing ring  20  to the spacers  18 . The spacers  22 , which are similar to the spacers  18  have, however, a greater length and support a contacting ring  24  which is fixedly connected to the spacers  22  and forms the top side of the frame. The housing  14  is formed from a top side  26 , a bottom side  28  and also a side end  30 , with the side end  30  being designed for coupling onto the lifting means. The sides  26  and  28 , which are identically formed in their dimensions, are approximately trapezoidal and each has an approximately circular cut-out at its side edges facing the frame  12 , with the radius of the circular cut-out corresponding approximately to the radius of the inner diameter of the support ring  16  and of the contacting ring  24  respectively. The top side  26  and the bottom side  28  of the housing  14  are so secured to the frame  12 , with the aid of the spacers  18  and  22  and also additional attachment elements which are not shown, that the frame  12  and the housing  14  form a self-supporting design. 
     A centering device  32  is provided on the support ring  16  shown at the bottom in FIG.  1  and will be explained in more detail in the following with reference to FIG.  2 . The centering device  32  has a centering ring  34  arranged concentric to the support ring  16 , with the centering ring  34  being rotatably mounted in a total of six bearing jaws, and having a small spacing from the upper side of the support ring  16 . The bearing jaws  36  are respectively combined into pairs, with the pairs being secured to the support ring  16  with a uniform spacing around the circumference. Between each pair of bearing jaws  36 , there is provided a lever  38  which is pivotally mounted on the support ring  16  and projects into the gap formed between the support ring  16  and the centering ring  34 , with the lower side of the centering ring  34  being supported on the lever  38 . A positioning groove  40  is formed in the longitudinal direction of each of the three levers  38 , and a spigot  42  which projects from the lower side of the centering ring  34  stands in engagement with the positioning groove. 
     One end of a push-rod  44  is pivotally connected to the centering ring  34  between the two pairs of bearing jaws  36 , close to the underside  28  of the housing  14 . The other end of the push-rod  44  is pivotally connected to a spindle nut  46 , which stands in engagement with a spindle  48  of a spindle drive  50  secured to the bottom side  28 . The spindle  48  of the spindle drive  50  is connected by a bevel gear  52  to the drive shaft of an air motor  54 , with a torque limiter  56  being provided between the bevel gear  56  and the drive shaft of the air motor  54 . An electric drive, such as for example a positioning motor or stepping motor, with which the spindle drive  50  can be actuated, is also suitable in place of the air motor  54 . 
     For the centering of the frame  12  at the mold to be cleaned, the frame  12  is threaded by the lifting device onto the lower part mold (not shown) of the mold, so that it projects through the central opening of the support ring  16 . Thereafter, the air motor  54  is actuated and drives the spindle  48  to rotate the spindle drive  50 . By the rotation of the spindle  48 , the spindle nut  46  is moved in the longitudinal direction of the spindle  48 , with the push-rod  44  transmitting the movement of the spindle nut  46  to the centering ring  34 . The centering ring  34  is rotated during this in a first direction of rotation (in the counter-clockwise sense in FIG.  2 ), with the pivotally mounted lever  38  being pivoted towards the inside by the spigots  42  of the centering ring  34 , which stand in engagement with the positioning grooves  40 . During this the levers  38  come into contact at their ends remote from the mounting point with the preferably rotationally symmetrical, circumferential surface of the part mold. Through the uniform movement of the levers  38  the frame  12  is aligned by the levers  38  contacting the circumferential surface so that the support ring  16  is arranged with its central opening at least approximately concentric to the lower part mold. As soon as the levers  38  contact the circumferential surface of the part mold with a predetermined force, the torque limiter  56  switches off the air motor  54 , whereby the centering process is terminated. The support ring  16  is kept in its aligned position with the aid of the levers  38  contacting the part mold until the cleaning process is concluded. After the cleaning the air motor  54  is activated anew and rotates the centering ring  34  in the opposite direction of rotation to the first direction of rotation, whereby the levers  38  of the support ring  16  are pivoted back into their starting positions shown in FIG. 2 in which they are moved out of the central opening of the support ring  16 . 
     FIG. 3 shows a rotary mount  58  provided in the apparatus  10 . The rotary mount  58  has a rotatable ring  60  which is rotatably mounted on the bearing ring  20 . For this purpose a radially inwardly projecting bearing collar  62  is formed on the bearing ring  20  and has two bearing surfaces which extend inclined to one another at an angle. Six bearing rollers  64  are rotatably mounted distributed uniformly around the circumference and are supported on the underside of the bearing collar  62 . Furthermore, six bearing rollers  66  are provided symmetrically between the bearing rollers  64  and are supported on the upper side of the bearing collar  62 , so that the rotatable ring  60  is uniformly held in the bearing ring  20 . 
     A projection  68  extends from the underside of the rotatable ring  60  facing the support ring  16  and projects through the bearing ring  20 , with a toothed arrangement for a toothed belt  70  being formed at the outer circumferential surface of the projection  68 . The toothed belt  70  in turn engages with a drive pinion of a drive motor  71  secured to the bottom side  28  of the housing  14 . With the aid of the drive motor  71 , the rotatable ring  60  can be turned to and fro in the clockwise sense or in the counter-clockwise sense of FIG. 1 in the bearing ring  20 . At its inner circumferential surface, the rotatable ring  60  has a support step or shoulder  72 , which serves for the attachment of a handling device  74 , which will be subsequently explained in more detail with reference to the FIGS. 4 to  6 . 
     As FIG. 4 shows, the handling device  74  has an attachment plate  76 , which is fixedly connected to the rotatable ring  60  by a holder  78 , with the holder  78  being supported, amongst other things, on the support step  72 . The flat side of the attachment plate  76  extends at least approximately parallel to the direction of the axis of rotation of the rotatable ring  60 . Two identically formed bearing brackets  80  project from the front side of the attachment plate  76  facing the frame  12 , close to the two side edges, and a pivoting plate  82  is pivotally mounted on the bearing brackets. A telescopic arm  84  is secured at the center of the pivoting plate  82  and extends in the radial direction into the frame  12 . A pivotal mount  86 , with which a cleaning pistol  88  is pivotally mounted on the telescopic arm  84 , is provided at the free end of the telescopic arm  84  remote from the attachment plate  76 . Both the pivotal position and also the length of the telescopic arm  84  are adjusted with the aid of self-locking threaded spindles (not shown). The pivotal position of the cleaning pistol  88  is likewise set by a self-locking threaded spindle (not shown). 
     A drive device  90  is further received in the housing  14  for the adjustment of the threaded spindle for the cleaning pistol  88  and for the threaded spindles for the telescopic arm  84 . The drive device  90  is coupled, for the adjustment of the pivotal position of the cleaning pistol  88  and of the pivotal position of the telescopic arm  84  and also for the adjustment of its length to the threaded spindles, as will be explained in the following. The drive means  90  has a total of four servomotors  92 , which are jointly secured on a carriage  94 . The carriage  94  is displaceably mounted on a guide  96  secured to the bottom side  28  of the housing  14  and can be moved in the radial direction with respect to the rotatable ring  60  between a rest position in which it is spaced from the rotatable ring  60  and a coupling position in which it is moved towards the rotatable ring  60 . 
     The coupling process and the adjustment of the handling device  74  will be explained in more detail in the following with reference to FIG. 5 in which the coupling position between one of the servomotors  92  and one of the threaded spindles  98  of the handling device  74  is schematically illustrated. To the end face of the drive shaft of each servomotor  92  there is secured a coupling element  100  which is a component of a releasable coupling device  102 , by means of which the respective servomotor  92  can be coupled to the threaded spindle  98  associated with it. The respective threaded spindle  98  has in turn a coupling element  104  of the coupling device  102  at its end confronting the servomotor  92 , which can be coupled to the coupling element  100  of the respective servomotor  92 . The threaded spindle  98  is rotatably mounted in a bearing aperture  105  in the attachment plate  76  and extends in the direction of the telescopic arm  84 , at which it co-operates in known manner with the positioning devices of the telescopic arm  84  and of the pivotal mount  86 . 
     A brake plate  106 , which is only illustrated in FIG. 5 for reasons of clarity, is arranged spaced from the attachment plate  76  and extends parallel to the attachment plate  76 . A radially outwardly projecting collar  108  is formed between the two plates  76  and  106  on each threaded spindle  98  and prevents direct contact of the braking plate  106  against the attachment plate  76 . The braking plate  106  is displaceably mounted and is biased by a plurality of springs  110  in the direction towards the attachment plate  76 . The braking plate  106  can be moved between a braking position, in which it clamps the collar  108  of the threaded spindles arranged between it and the attachment plate  76  between itself and the attachment plate  76 , and a release position, in which the braking plate  106  releases the collar  108 . 
     In order for the braking plate  106  to be moved against the force of the springs  110  into its released position, a pin  112  is secured to the carriage  94  and extends in the direction of the braking plate  106  through a passage bore  114  formed at the attachment plate  76 . The pin  112  is so secured to the carriage  94  that its end face comes into contact with the flat side of the braking plate  76  when the carriage  94  is moved from its rest position into its coupling position. 
     soon as the handling device  74  is to be adjusted, the carriage  94  is moved by a non-illustrated drive from its rest position into its coupling position, with the two coupling elements  100  and  104  of the coupling device  102  first coming into engagement with one another. During the entry into engagement of the coupling elements  100  and  104 , the pin  112  of the carriage  94  presses, during the movement of the carriage which is continued into its final coupling position, against the braking plate  106 , whereby the braking plate  106  is moved against the force of the springs  110  out of its braking position into its release position. As soon as the carriage  94  has reached its coupling position, the coupling elements  100  and  104  are, on the one hand, coupled to one another in an orderly manner and, on the other hand, the braking plate  106  is moved sufficiently far away from the collars  108  of the threaded spindles  98  that these are now braked by their self-locking characteristics and by the coupling to the servomotors  92 , but not, however, by the braking plate  106 . Thereafter, the various servomotors  92  are activated which drive the threaded spindles  98  coupled to them, whereby the telescopic arm  84  is extended or retracted and also lifted or lowered, while at the same time the position of the cleaning pistol  88  is changed, as is shown in FIG.  6 . After the desired position has been set, the servomotors  92  are stopped and the carriage  94  is moved into its rest position again, in which the coupling elements  100  of the servomotors  92  are decoupled from the coupling elements  104  of the threaded spindles  98 . During the movement of the carriage  94  into its rest position, the braking plate  106 , which is supported with its flat side against the pin  112  of the carriage  94  is moved by the force of the springs  110  into its braking position again, in which it contacts the collars  108  of the threaded spindles  98  under bias and locks these. As soon as the pin  112  of the carriage  94  no longer contacts the braking plate  106 , the coupling elements  100  and  104  of the coupling device  102  come out of engagement, so that the drive means  90  is decoupled from the handling device  74 . 
     In the following the manner of operation of the apparatus  10  is explained in more detail with reference to FIG.  7 . As soon as it is established, during tire manufacture, that the vulcanization mold is contaminated to too great a degree, the apparatus  10  comes into use. For this purpose the two part molds of the vulcanization mold, of which only the upper part mold  116  is shown in FIG. 7, are initially moved sufficiently far apart so that the frame  12  of the apparatus  10  can be moved between the two part molds  116  with the aid of the non-illustrated lifting device. Thereafter, the frame  12  is lowered to such an extent that its support ring  16  is supported on the press bed of the vulcanization device. Thereafter, the non-illustrated control of the apparatus  10  activates the air motor  54  of the centering device  32 , so that the frame  12  is aligned in the manner described with reference to FIG. 2 at the non-illustrated lower part mold. As soon as the alignment process has been concluded, the part mold  116  shown at the top in FIG. 6 is lowered to such an extent that its lower side comes into contact with the upper side of the contacting ring  24 . In this manner the press bed with the lower part mold, the jacketed frame  12  and also the upper part mold  116  forms a cleaning chamber which is closed off towards the outside. 
     After the frame  12  has been positioned in the above described manner, the drive means  90  is coupled to the handling device in the manner previously described with reference to FIGS. 4 to  6  and the cleaning pistol  88  is moved by activation of the servomotors  92  into a defined position with respect to the mold surface  118  of the vulcanization mold which is to be cleaned. In the example shown in FIG. 7, the cleaning pistol  88  is moved out of its rest position (shown in broken lines) into its working position (shown in continuous lines) in which it is aligned with the mold surface of the upper part mold  116 . For the cleaning of the lower part mold the cleaning pistol  88  can be moved through the central opening of the lower support ring  16 . 
     After the positioning of the cleaning pistol  88  has been concluded, which has taken place with the aid of a comparatively simply programmed control program, with which a total of only three axes of the handling device  74  are adjusted, the drive means  90  is decoupled again from the handling device  74 , with the braking plate  106  locking the threaded spindles  98  in their selected positions, so that after the decoupling of the drive means  90  the cleaning pistol  88  remains in its desired position. 
     After the positioning of the cleaning pistol  88 , the drive of the rotary mount  58  is switched on, with the cleaning pistol  88  being simultaneously supplied with dry ice pellets which are mixed into a compressed air stream emerging from the cleaning pistol  88 . As soon as the dry ice pellets escape from the cleaning pistol  88 , the total handling device  74  is rotated with the aid of the rotatable ring  16  moved by the drive motor  17 , with the axis of the rotatable ring  60  having previously been aligned with the axis of symmetry of the part mold  116  through the alignment of the frame  12 . In this way it is ensured that the cleaning pistol  88  is moved relatively past the mold surface  118  of the part mold  116  at a constant spacing for the cleaning. As soon as the handling device  74  has been moved through a full rotation of 360°, the drive of the rotatable ring  60  is switched off and the dry ice supply is interrupted. Thereafter, the drive means  90  is coupled anew to the handling device  74  and the cleaning pistol  88  is adjusted into a new position. After the setting of the new position, the drive means  90  is decoupled again from the handling device  74 , with the braking plate  106  securing the position of the cleaning pistol  88 . 
     Thereafter a new cleaning cycle is commenced, and in this case the rotatable ring  60  moves jointly with the handling device  74  in a direction of rotation which is opposite to the direction of rotation during the immediately preceding cleaning cycle. In this manner a situation is achieved in which the supply lines (not shown) of the cleaning pistol  88  leading to the bearing ring  20  are moved in the one direction during one cleaning cycle and in the opposite direction during the subsequent cleaning cycle so that multiple winding or twisting of the supply lines around the rotatable ring  60  is avoided. 
     The coupling on and decoupling of the drive means  90  and also the setting of the cleaning pistol  88  and the subsequent rotation of the handling device  74  is repeated until the mold surface  118  of the part mold  116  has been cleaned. Thereafter, the non-illustrated lower mold part of the vulcanization mold can be cleaned in the same manner with the aid of the cleaning pistol  88 . 
     As soon as the cleaning of the vulcanization mold has been concluded, the molds are moved apart from one another, the centering device of the frame  12  is moved back into its starting position again in which the levers  38  are pivoted away from the mold and thereafter the frame  12  is drawn out of the vulcanization device with the aid of the lifting apparatus. In order not to delay the operation of the vulcanization device unnecessarily, it is furthermore proposed that the part molds  116  of the vulcanization mold should also be kept at a temperature in the range of 155 to 160° C. during the cleaning process, so that after the cleaning of the vulcanization mold the manufacture of tires can be continued without interruption or delay for reheating.