Abstract:
The invention concerns a device for assembly of tubular cylindrical carriers ( 8 ) on the circumference ( 22 ) of carrier cylinders ( 1 ) of drums or cylinders, wherein for the assembly of the tubular carrier ( 8 ) on the lateral surface ( 22 ) a pressure medium acts upon the latter. By attaching an assembly aid ( 4 ), on which a tubular carrier ( 8 ) can be held, on the carrier cylinder ( 1 ), a pressure medium acts upon the latter, so that positioning of the tubular carrier ( 8 ) is made possible.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for assembly of tubular carrier elements, for example tubular channelless carriers, on the circumference of which a functional layer can be made in the form of a photoelectric layer. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 5,215,013 refers to device for noise damping in the case of covering the peripheral area of a press cylinder with a tubular rubber blanket. This device preferably is used on the press of an offset press, which is equipped with channelless press cylinders. The rubber blanket is expandable in the circumferential direction, for which a pneumatically generated pressure can act on the inside of the rubber blanket sleeve. Then the expanded rubber blanket sleeve is pushed laterally over the surface of the cylinder. The rubber blanket sleeve is provided with a damping ring for damping the noise, which is caused by the lateral emergence of the compressed air. The high-frequency noise, generated by oscillations of the rubber blanket sleeve which is under pressure, is damped by the damping ring. The cylinder surface is provided with exit holes, which create and maintain the air cushion at the time of pursing the rubber blanket sleeve over the surface of the cylinder, at the place at which the rubber blanket sleeve is set laterally on the cylinder surface for pushing. 
     U.S. Pat. No. 5,649,267 refers to a cylinder arrangement which can be used in a press unit. An essentially tubular element, on the surface of which a toner image can be generated, is used on the cylinder arrangement which is made essentially drum-shaped. The drum surface includes open ends, the flat sides of which are supported by disk-like peripheral areas supporting the lateral surface. The flat sides, with which the openings of the cylindrically configured surface can be closed, are cooled before assembly, in order then to be let into the openings of the surface. The flat sides, which are shrunken into the cylinder surface ends in this way, in this case are provided with shaft bearings. A shaft passing through the drum arrangement in the axial direction is received in the shaft bearings. The eccentricity of the drum casing can be preset relative to the rotation axis by the adjustment screws provided on the flat sides. 
     In the case of electrographic press units, wear of the functional layer takes place on cylinders, the surface of which can be provided with a functional layer, for example a photoelectric layer. This wear of the functional layer makes replacement of the functional layer necessary. In order to be able to perform the replacement, the sleeve which holds the functional layer in each case is changed inside or outside the press unit. In this case a positionally correct pushing of the cylinder sleeve carrying the functional layer is mandatory. 
     SUMMARY OF THE INVENTION 
     In view of the solutions known from the prior art and the technical problem indicated, the object of the invention is to make reliable assembly of a cylinder covering on a carrier cylinder possible. 
     According to the invention this object is achieved by the features of Patent claim  1 . 
     The advantages resulting from the solution proposed according to the invention are to be seen above all in the fact that the covering to be applied can be positioned laterally almost seamlessly on the surface of the carrier cylinder by setting the assembly aid on a flat side of the carrier cylinder. The air cushion generated by a pressure medium, supporting the process of mounting the tubular carrier, is created only when the assembly aid is positioned on the stop surface of the carrier cylinder correspondingly provided therefor. The surface of the tubular carrier to be mounted is protected effectively on the assembly aid, since a cover overlapping the surface of the covering tubular carrier is provided. 
     In a further configuration of the concept on which the invention is based, in each case switch elements for switching the pressure medium on and off can be provided on the carrier cylinder or in the assembly aid. This assures that the pressure medium is applied only when it is also actually necessary, namely during the process of positioning the tubular carrier to be applied laterally onto the surface of the carrier cylinder. 
     The circumstance that the action of exit openings for the pressure medium in each case exerted on the peripheral surface of the assembly aid and on the circumference of the carrier cylinder takes place only when assembly aid and carrier cylinder lie against one another on a stop surface is particularly advantageous. The correct arrangement of the assembly aid on the carrier cylinder can be achieved by having one of the bearing pins of the carrier cylinder serve as a centering element. The bearing pin serving as a centering element works together with a receptacle provided inside the assembly aid, which in a preferred configuration can be made as a hole extending along the rotation axis of the assembly aid and the carrier cylinder. The receptacle can be made both parallel to the rotation axis of the assembly aid and the centering element; the receptacle can be made just as well coaxial to the rotation axis of the carrier cylinder and assembly aid. In order to assure the centering of the assembly aid on the bearing surface of the carrier cylinder, the receptacle can be provided with an opening on a flat side, in which an end of the bearing pin functioning as a centering element can be received. The accuracy and duration of the centering is increased significantly by having the receptacle overlap the end of the bearing pin with a covering area, so that the centering of the assembly aid can be maintained while it lies tight against the bearing surface. The assembly aid includes an outlet opening into its lateral surface for a pressure medium, wherein the latter opens in particular in an area under cover protecting the tubular carrier. A ring slot extending over the axial length is made between the lateral surface of the assembly aid and the cover for protecting the surface or the tubular carrier. 
     In order to assure that the pressure medium acting on the carrier cylinder and assembly aid can be switched on and off in the case of axial positioning of the tubular carrier, an operating element is made on the assembly aid. The operating element, for example made as a pin, penetrates a flat side of the carrier cylinder in the case of contact of the assembly aid with a bearing surface on the carrier cylinder, and causes a pressure medium to flow out into the corresponding outlet openings on the lateral surface of carrier cylinder and assembly aid. 
     The operating element made, for example, as a pin can be operable also in the axial direction; operation of the same in the radial direction is equally well conceivable. In the case of pin-shaped configuration of the operating element provided on the assembly aid the latter penetrates the flat side in the case of installation of the assembly aid on a bearing pin of the carrier cylinder and corresponding centering by holding on a bearing pin of the carrier cylinder in such a way that the end of the operating element is in contact with a conical switch element, which operates a valve provided with the carrier cylinder. The pressure provided via a pressure medium line is directed into the carrier cylinder opening via a connection through the bearing pin turned away from the bearing surface onto the surface of the carrier cylinder and assembly aid. In addition, outlet openings are made in the mounting area of assembly area and carrier cylinder, which both open into the hole which is penetrated by the operating element and into which the pressure medium flowing out from the pressure line released by the valve arrangement in the carrier cylinder opens and which acts upon the peripheral surfaces of the two components mentioned. 
     The device proposed according to the invention advantageously can be used in a press with which both a web-like printing material as well as a printing material in sheet form can be printed on one or both sides. The press can be part of a printing press, which contains one or more presses, a toner image being generated on the lateral surface of the channel-less tubular carrier form to be mounted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention is explained in greater detail below by reference to the drawing. 
     Here: 
     FIG. 1 shows a longitudinal section through a carrier cylinder arrangement with a switch valve held in the interior for the pressure medium supplied on the bearing pin side; 
     FIG. 2 shows a longitudinal section through a mounting aid with a receptacle made coaxial to the axis of rotation of the assembly aid and in which with a pin-shaped operating element held on the flat side, for example screwed in here, for the switch arrangement of a carrier cylinder, and 
     FIG. 3 shows the assembly aid centered on a bearing pin of the carrier cylinder, carrier cylinder and assembly aide lying against one another on a bearing surface and the operating element acting on a pendant on the switch valve for releasing the pressure medium. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It follows from the presentation according to FIG. 1 that there is a carrier cylinder with bearing pins in each case held on the flat sides, through the interior of which a supply line of a pressure medium extends up to a valve arrangement. 
     The carrier cylinder  1 , made essentially rotation-symmetrical to its rotation axis, contains two bearing pins  2  and  20 , of which bearing pin  2  serves as a centering pin. In its interior, which is bounded by flat surfaces  21 , and  23 , there is a switch element  3 , which can be made, for example, as a pneumatic switch element. Between switch element  3  and a pressure medium supply line  22  there is a valve arrangement  13 , which functions essentially as a two-way valve arrangement. An adjustable throttle element  14  is associated with the valve arrangement  13 . The throttle element  14  serves to enable pressure in an outlet opening  9 , which opens into a lateral surface  22  of the carrier cylinder  1 , to be removed. 
     A conical operating element  15 , aligned with a spacer  17 , in which a hole  16  is formed, is located in operative association with the pneumatically operating switch element  3 . The hole  16  in the spacer  17  essentially aligns with the hole  18  in the flat surface  23  and is, for example, screwed into the latter via a thread. The bearing pin  2  of the carrier cylinder functioning as a entering pin is held on the flat surface  23  and fits against the inside of the flat surface via a collar  19  carried by the carrier cylinder. A mounting surface, serving as a centering surface, for the collar  19  is a thread on the centering pin  2 . 
     On the opposite bearing pin  20  of the carrier cylinder  1 , according to the invention, a supply line  12  of a pressure medium is essentially coaxial, with the bearing pin and penetrates the carrier cylinder  1 . The pressure medium supply line can be passed through to carrier cylinder as a compressed air line with an end in juxtaposition with the valve arrangement  13 . 
     The lateral surface  22  of the carrier cylinder  1  is, as shown in FIG. 1, a channelless uninterrupted peripheral area, onto the circumference of which a tubular carrier  8  (not shown in FIG. 1) can be pushed and positioned. For example, the tubular carrier  8  can be a cylinder sleeve, on the surface of which an electrographic layer can be formed. A toner image can be created on the electrographic layer according to the electrography principle. 
     Instead of an uninterrupted bearing piece penetrating the carrier cylinder  1  penetrating from flat surface  23  to flat surface  21 , in the presentation according to FIG. 1, the bearing, centering pins  2 , and  20  are mounted as pins, in each case in their flat sides  21 , respectively  23 . This produces an open space within the cavity of the carrier cylinder  1 , in which the switch element  3 , the valve arrangement  13 , as well as the adjustable throttle  14  and the pressure medium supply line  12  extending from the bearing pin  20  can be held. 
     According to the representation shown in FIG. 2, there is a longitudinal section through the assembly aid proposed according to the invention, through which a receptacle  5  passes coaxial to the rotation axis. 
     From the representation showing in FIG. 2 it follows that the assembly aid  4  essentially is a lateral surface  34  and two flat surfaces  35  and  36 . In the flat surface  35 , which is located opposite an operating element  6 , a receptacle  5  is mounted coaxial to the rotation axis of the assembly aid  4 . The receptacle  5  extends essentially over more than half of the axial extent of the assembly aid  4 . The receptacle  5  is penetrated by a hole  32  extending axially. The operating element  6  secured to the flat surface  35 , opposite the end of the receptacle  5 , is a pin which extends through a hole  6   a  outwardly of the assembly aid  4 . An outlet hole  10 , which opens into the lateral surface  34  of the assembly aid  4 , branches from the hole  6   a . In addition to the pin-shaped configuration of the operating element  6  shown, it can also be made in different shapes. In the flat surface  35  receiving the operating element  6  (here shown as a pin) there is also an opening  24  (see FIG.  3 ), which can be penetrated by the bearing pin  2  of the carrier cylinder  1 , accordingly functioning as a centering pin. The end opening  28  of the receptacle  5  is located opposite the receiving hole  24  in the flat surface  35  to receive the free end  29  of the bearing pin  2 . 
     A tubular carrier  8  can be held on the circumference of the assembly aid  4 , in a ring slot  25 , bounded by the lateral surface  34  of the assembly aid  4  and a protective covering  7  extending coaxial hereto. The surface of this tubular carrier, for example a photoelectrically sensitive coating, is effectively protected with this covering  7  against external influences such as scratching, contact, or wetting with liquids or fluids, and therefore is very extensively shielded against external influences in the case of handling. 
     An assembly aid  4 , which is supported on bearing pin  2  and centered relative to flat surface  23 , (functioning as a thrust_bearing surface  31 ), follows from the representation according to FIG.  3 . 
     From the representation shown in FIG. 3, it follows that the assembly aid  4  lies against the flat surface  23  of the carrier cylinder  1 . The bearing pin  2  extending from the flat surface  23 , from the collar  19  on the inside of the flat surface  23 , functions as a centering pin in this representation. The bearing pin  2  is pushed with its narrowed projection end  29  into the end opening  28  of the receptacle  5 , which penetrates the assembly aid  4  coaxially to the rotating axis thereof. 
     The centering of the assembly aid  4  takes place essentially by introducing the narrowed end  29  of the bearing pin  2  into the receptacle receiving hole  18  of the receptacle  5 . 
     In this way it is assured that the operating element  6  (pin-shaped element) penetrates the hole  6   a  in the flat surface  35  of the assembly aid  4  containing the receiving hole  24 , and is aligned with and enters the hole  18  penetrating the flat surface  23  of the carrier cylinder  1 . This hole  18  opens (see representation according to FIG. 1) into the hole  16  of the spacer  17 , which lies opposite the conical operating element  15  of the pneumatic switch element  3 . If the pin-shaped operating element  6  comes in contact with the surface of the conical operating element, the valve arrangement  13  in the interior of the carrier cylinder  1  is operated and releases the feed of a pressure medium into the outlet openings  9  and  10 . There is a sensor (not shown) in the outlet opening  9 , which is provided on the flat surface  23  of the carrier cylinder  1 . The sensor responds to the presence of a tubular carrier  8  to be pushed over the lateral surface  22  by an attached assembly aid  4  and switches the valve arrangement via the throttle element  14  in such a way that the latter is brought to a volume flow for generating a force sufficient to enable pushing the tubular carrier  8  onto the lateral surface  22 . As soon as the air cushion is formed, the tubular carrier  8  is moved onto the lateral surface  22  of the carrier cylinder  1 . 
     In this way the tubular carrier  8 , still enclosed by the covering  7 , is easily expanded by the formation of an air cushion and can be pushed laterally onto the lateral surface  22  of the carrier cylinder  1 . By the seamless transition between the lateral surface of the assembly aid  4 , with the lateral surface  22  of the carrier cylinder  1 , a slight expansion of the tubular carrier is sufficient to enable the tabular carrier to be pushed laterally onto the lateral surface  22  of the carrier cylinder  1 . The air cushion forming on the assembly aid  4 , generated by the outlet opening  10 , enables the tabular carrier to be advanced seamlessly onto the lateral surface  22  of the carrier cylinder  1 . The outlet opening  9  (provided in the flat surface  23 ), which opening is acted upon by the pressure medium flowing into the hole  18 , supports the formation of an air cushion on the lateral surface  22  of the carrier cylinder  1  under the tubular carrier element  8 . 
     By attaching the assembly aid  4  to the carrier cylinder  1  first (i.e., before trying to mount the tubular carrier  8  on the carrier cylinder), there is a contact of the operating element  6  with the conical operating element  15  of the valve arrangement  13  so that the pressure medium can be provided only when it is needed for covering the lateral surface  22  of the carrier cylinder  1  with the tubular carrier. During the lateral positioning of the tubular carrier  8  on the lateral surface  22  of the carrier cylinder  1 , the centering of the peripheral surfaces of the assembly aid  4  and carrier cylinder  1  is ensured by enclosing the bearing pin of the carrier cylinder  1  (centering pin  2 ) effectively by the receptacle  5  in the assembly aid  4  and maintaining the centering. In this way an alignment of the flat surface  35  of the assembly aid  4  with the flat surface  23  during the lateral positioning of the tubular carrier  8 . 
     The adjusting of the valve arrangement  13  to control compressed air volume flow can be controlled by equipping the outlet opening  9  in the flat surface  23  with a sensor element. As soon as the tubular carrier  8  passes from the lateral surface of the assembly aid  4  to the lateral surface  22  of the carrier cylinder  1 , the sensor in the outlet opening  9  detects this passage and increases the volume flow via the adjustable throttle element  14  from a first volume flow to a second stronger volume flow. In this way an air cushion, which permits a lateral displacement of the tubular carrier  8  from the assembly aid  4  onto the lateral surface  22 , is formed under the tubular carrier  8  to be installed. If the tubular carrier  8  has reached its position and the assembly aid  4  centering pin  2  is removed from the assembly aid, the pin-shaped operating element  6  emerges from the hole  18  and releases the conical operating element  15 . In this way the compressed air volume flow is switched off in the valve arrangement  13 . 
     The invention has been described in detail with particular reference to certain preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.