EP1967360B1 - Sleeve and clamp tool for use in a system comprising one clamp tool and at least one sleeve - Google Patents

Description

The invention relates to a sleeve and a clamping tool for use in a system consisting of a clamping tool and at least one sleeve.

In the flexographic printing industry, many such systems are in use, in which the sleeves are mounted by means of air pressure. The carrier cylinders for the sleeves are relatively simple, while the sleeves themselves are complex. Examples are in the EP 0 865 933 A1 and in the EP 1 361 073 A2 shown. The sleeves consist of several layers to allow mounting and clamping.

From the gravure area systems are known which work with several clamping segments, as in the US 5,971,314 and the US 4,624,184 The latter uses hydraulic clamping segments. These systems have many components and have no homogeneous clamping force over the entire surface of the sleeves. On the other hand, there are hydraulic tensioning systems that provide the homogeneous clamping force, such as the system according to US 3,166,013 , but which do not have sufficient bending stiffness and compressive strength and also can not ensure a sufficiently strong power transmission to the sleeves to be clamped.

The EP 1 327 522 A1 discloses a tightening tool for use in a system of a tightening tool and at least one sleeve, comprising an inner body having a central axis and an outer body having a central axis coaxial with the central axis of the inner body, the inner body and the outer body being formed in the region of their faces to form Tie rods are firmly and pressure-tightly connected to each other and a means for applying the pointing to its central axis surface of the outer body with pressure is provided. Similar devices are also known from EP 1 004 455 A2 and from the EP 1 703 745 A1 known.

It is the object of the present invention to provide a system of at least one sleeve and a clamping tool and also a method for producing a sleeve, which are significantly cheaper to manufacture and also of higher quality than the systems that are used so far.

This object is achieved by a clamping tool for use in a system comprising a clamping tool and at least one sleeve according to claim 1. A corresponding system is the subject matter of claim 8 and a method for producing a sleeve is specified in claim 15. The dependent claims relate to advantageous embodiments of the invention.

According to the invention, it is provided that the clamping tool is characterized in that the outer body in the region between the tie rods has a material with a lower modulus of elasticity than that of the remaining material of the outer body. The sleeve can be made entirely of a castable material. The castable material may be an elastomeric or thermosetting plastic, in particular an epoxy resin, or else a metal or a metal alloy. The castable material may be mixed with the modulus of elasticity and / or the stiffness and / or the conductivity-increasing and / or the weight-reducing fillers, in particular glass fibers, glass balloons, aramid fibers, carbon fiber, electrically conductive fibers and band-shaped materials. The sleeves are thus produced in a casting process that can be carried out both in vacuum and under normal atmospheric pressure or overpressure.

Compared with the prior art, which uses polyurethane foams, for example, epoxy resins with a glass fiber or glass balloon filling have an increased mechanical strength and better dimensional stability with a significantly lower coefficient of thermal expansion and significantly higher compressive strength. When casting according to the invention suitable metals or metal alloys, such as aluminum or non-ferrous metals, such as copper, the same advantages apply. The increased dimensional stability causes in the various finishing processes, such as gumming, galvanization, coating with various materials as well as in the later printing process a significantly improved dimensional stability, in terms of concentricity and volume, thus ensuring an improved and more stable print result.

The inner profile of the sleeve can be conical or cylindrical. Conical inner contours can be produced on a corresponding tapered tool, wherein due to the Entformungsschräge a subsequent demolding is not a problem. For inner contours that are not conical, the sleeve is made on an expanded mold, which is contracted after the impression and thus allows easy removal from the mold. The outer shape, ie the casting mold, can be designed analogously to the manufacturing core as an expandable shape.

Depending on the choice of material composition different force-strain curves of the sleeves can be adjusted. Depending on the design and expansion pressure in the production of a sleeve on an expandable core various inner contours can be generated, for example, sleeves can be produced which have over their length a varying wall thickness and thus compensate for the subsequent bending, as occurs in a printing press. The varying wall thickness is not generated by a subsequent machining process, but via the variable core profile of the production tool. According to the invention, the manufacturing core is constructed like the clamping tool described below.

It is thus described a cylindrical as well as a conical sleeve system, which is essentially manufactured in only one operation and can be adapted later flexibly to the required printing size or embossing circumference, without this having to be taken into account in the production beforehand. The sleeves of the invention are much more dimensionally stable than conventional sleeves in processing as well as in the printing process. Thus, for the cheaper adaptation to the different pressure ranges and several sleeves using the clamping tool according to the invention can be pushed into each other and simultaneously clamped without special holes, valves or other tools are needed.

The carrier cores used for the sleeves are similar in their manufacture as comparable, comparable with air-working systems, but much cheaper than mechanical or hydraulic clamping shafts, which are used today in the flexographic or gravure printing industry. However, since the carrier cores in much smaller quantities than the Sleeves are required for the user of the new technology not only a quality, but also a cost advantage.

The device for applying pressure to the surface of the outer body facing towards its central axis preferably has at least one channel provided in the inner body, which opens into the surface of the inner body pointing away from its central axis.

Preferably, the inner body is formed in the region of its end faces to form the tie rods with greater wall thickness than in a central region. More preferably, the region of greater wall thickness of the inner body is formed as an annular flange, against which the end faces of the outer body.

Finally, the outer body may have a variable wall thickness at least in the axial direction.

The clamping tool takes into account the requirement that for high-quality printing and embossing applications a very homogeneous clamping of the sleeves on a carrier core or a tensioning shaft must be ensured. Conventional segmented mechanical or hydraulic tensioning systems are detrimental to high quality printing because any undulations, pressure differences across the circumference or length of the tensioning means and differential strains on the surface of the tensioning means have a negative impact on the subsequent printing result.

Thus, in particular in connection with one or more sleeves of the present invention, a high dimensionally stable system is created, which meets the ever-increasing quality requirements of the industry.

An inventive clamping tool can be used for producing a sleeve.

1. a) Bereitstellen eines Fertigungskerns mit den Merkmalen eines erfindungsgemäßen Spannwerkzeuges;
2. b) Expandieren des Fertigungskerns auf das gewünschte Innenmaß der Sleeve;
3. c) Umschließen des Fertigungskerns mit einer Außenform;
4. d) Vergießen des Hohlraums zwischen Fertigungskern und Außenform mit gießbarem Material, welches gegebenenfalls mit Füllstoffen versetzt ist;
5. e) Aushärten des gießbaren Materials; und
6. f) Aufheben der Expansion des Fertigungskerns.

A method for producing a sleeve comprises the following steps:

1. a) providing a manufacturing core with the features of a clamping tool according to the invention;
2. b) expanding the manufacturing core to the desired internal dimension of the sleeve;
3. c) enclosing the manufacturing core with an outer mold;
4. d) potting the cavity between the manufacturing core and outer mold with castable material, which is optionally mixed with fillers;
5. e) curing the castable material; and
6. f) Canceling the expansion of the manufacturing core.

It can be provided that the outer shape remains as an outer tube on the sleeve. Functional elements, such as identification chips, can be introduced into the cavity between the manufacturing core and the outer mold and cast in one operation.

Figur 1

eine Längsschnittansicht eines Spannwerkzeuges nach dem Stand der Technik;

Figur 2a

eine Längsschnittansicht eines Spannwerkzeuges nach einer ersten Ausführungsform;

Figur 2b

eine Längsschnittansicht eines Spannwerkzeuges nach einer zweiten Ausführungsform;

Figur 3

eine Längsschnittansicht eines Spannwerkzeugs ähnlich Figur 2 mit variabler Wandstärke des Außenkörpers;

Figur 4

ein System aus einem Spannwerkzeug und mehreren Sleeves;

Figur 5

eine schematische Darstellung eines Verfahrens für die Herstellung von Sleeves, die nicht über eine Entformungsschräge verfügen;

Figur 6

eine Längsschnittansicht durch eine Sleeve mit metallischem Außenrohr;

Figur 7

eine Längsschnittansicht durch ein System aus Spannwerkzeug mit Sleeve nach einer weiteren Ausführungsform der vorliegenden Erfindung.

In the following the invention will be explained in more detail with reference to the accompanying drawings. Showing:

FIG. 1

a longitudinal sectional view of a clamping tool according to the prior art;

FIG. 2a

a longitudinal sectional view of a clamping tool according to a first embodiment;

FIG. 2b

a longitudinal sectional view of a clamping tool according to a second embodiment;

FIG. 3

a longitudinal sectional view of a clamping tool similar FIG. 2 with variable wall thickness of the outer body;

FIG. 4

a system consisting of a clamping tool and several sleeves;

FIG. 5

a schematic representation of a method for the production of sleeves that do not have a Entformungsschräge;

FIG. 6

a longitudinal sectional view through a sleeve with metallic outer tube;

FIG. 7

a longitudinal sectional view through a system of clamping tool with sleeve according to another embodiment of the present invention.

A clamping tool or clamping core consists essentially of two components, the inner body and the outer body. After the example of FIG. 1 , which represents the prior art, in particular the partial image (a), an outer body 10 made of steel at its ends by welds 12, 12 'with a coaxially arranged inner body 20 is fixedly connected. The areas 14, 14 'serve as tie rods, so that the outer body 10 is not floating. Via a guided through the inner body channel 18, the outer body 10 can be pressurized and expanded by a medium. This pressure building up between the inner body 20 and the outer body 10 ensures that, as shown in part (b), the outer body 10 is raised from the inner body 20 to form a pressure chamber 16. For the construction of high pressures and the transmission of large forces, however, this system is not suitable, since the connection in the areas of the tie rods 14, 14 ', which are usually designed as a shrink fit, not stable enough and it is therefore in such strong Loads like a floating storage behaves.

FIG. 2a shows how these disadvantages can be compensated by a clamping tool according to the invention. Here, the edge regions 24, 24 'of the outer body 10, which form the tie rods, much larger dimensions than in the prior art FIG. 1 , In order that the area between the two tie rods 24, 24 'can nevertheless be stretched sufficiently, it has a coating 22 of a material with a substantially lower modulus of elasticity than the remaining material of the outer body 10. A suitable material system may for example consist of steel with a correspondingly high modulus of elasticity and epoxy resins with a correspondingly low modulus of elasticity. Thus, the inner body 20 due to the stable tie rods 24, 24 'thus be much thicker than selected in the prior art and provide a much higher flexural rigidity. This increased bending stiffness is also significantly improved by the coating 22 of the region between the two tie rods 24, 24 ', as it significantly increases the moment of resistance of the composite due to the large wall thickness, without significantly reducing the elongation. The system behaves in practice similar to a conventional steel core. The floating bearing and low bending stiffness are compensated. The bending line can still be significantly improved, as it relates to FIG. 3 is explained.

FIG. 2b shows a variant in which the coating 22 of the area between the two tie rods 24, 24 'directly adjacent to the inner body 20, so that the exposed part of the outer body 20 is of uniform material, for example made of steel.

In FIG. 3 a clamping tool is shown, in which the part of the outer body 10 is formed with a high modulus of elasticity in the longitudinal direction with different wall thicknesses. In this case, the wall has a higher wall thickness in its end regions A, C than in the middle region B. In the expanded state, the regions B with the smaller wall thickness then expand more strongly than the A, C with a greater wall thickness. Since the variable thickness profile is not found on the surface, the surface in the unexpanded state, for example, be cylindrical or conical, without having a camber on the surface. This increases the useful tensioning travel and makes the machining of the lower modulus material of the coating 22 easier. The result is a clamping tool that has a very homogeneous bending compensation and high bending stiffness and can transmit large forces.

Similarly, sleeves can be made with variable wall thickness, without having to resort to a curve or similar manufacturing process. For this purpose, a manufacturing core is used, which has a variable wall thickness. The different wall thicknesses result in different expansions and paths during expansion. If now a sleeve is produced on this production core and cylindrically machined after curing, this results in a sleeve with different wall thickness. This sleeve can then be clamped on a core with a homogeneous clamping path. The system of tension core and sleeve thus has different outer diameters, which may be useful for example for the bending compensation.

FIG. 4 shows a system with several spanned sleeves 30, 40. The sleeves 30, 40 are pushed onto the relaxed core. Subsequently, the core is expanded by introducing a fluid medium through the channel 18 to build a pressure chamber 16, wherein the outer body 10 lifts from the inner body 20. The clamping force initially stretches the sleeve 30 located above the coating 22 and transfers part of the clamping force to the overlying sleeve 40.

A method for the production of sleeves according to an embodiment of the invention is disclosed in FIG. 4 illustrated. In this case, a manufacturing core is preferably used which has the features of the clamping tool according to the present invention. First, as illustrated in panel (a), the manufacturing core 100 is expanded to the desired inner dimension of the sleeve. Subsequently, the manufacturing core 100 is enclosed with an outer mold 110 such that a cavity 120 between the manufacturing core 100th and outer shape 10 results. This cavity 120 is then cast with pourable material, which is optionally mixed with fillers. Subsequently, the castable material is cured, the sleeve 140 is completed. The expansion of the manufacturing core 100 is canceled, as seen in panel (b), so that the sleeve 140 is ready for removal. The outer jacket 110 can be removed or, according to a variant, which is shown in FIG. 6, at the same time form the outer tube of the sleeve. It can be provided, before the casting into the cavity 120 functional elements 150, such as identification chips to introduce.

FIG. 7 shows an air cylinder 200, as it is found, for example, in a modern flexographic printing press. In order to be able to use this air cylinder 200 optionally for the use of conventional flexo sleeves as well as for the sleeves described in the invention, an adapter 210 is located on the air cylinder 200. The adapter is expanded via a connection 218 with the aid of a fluid medium, for example hydraulically , and thus ensures by extension of the pressure chamber 216 for the necessary frictional engagement between the air cylinder 200 and the sleeve 220. If the clamping pressure is removed, so either the sleeve 220 and the adapter 210 can be deducted from the air cylinder 200. Tie rods 214, 214 'serve to stretch the adapter 210 in both directions, toward both the sleeve 220 and the air cylinder 200. The inner surface of the adapter is generally cylindrical in shape, the outer surface depending on the sleeve usually cylindrical or conical.

The system described can also be used for gravure printing, offset printing or intaglio printing in the roll and in the sheet process and for embossing web and sheet-like materials.

In general, the invention is suitable for the production of very dimensionally stable hollow bodies. For higher-quality and faster production of the sleeves, the tools can have a tempering circuit. The manufacturing cores can also have such a tempering circuit, and the hydraulic clamping pressure can be variably adjusted in the machine. The clamping devices themselves are also characterized by an absolutely flat surface, which has no ripple in comparison to the prior art. As a result, in the invention self-supporting as well as non-self-supporting sleeves can be used from a variety of materials and clamped with the clamping tools.

The features of the invention disclosed in the foregoing description, in the drawing and in the claims may be essential for the realization of the invention both individually and in any desired combination.

Claims (18)

1. A clamp tool for use in a system comprising a clamp tool and at least one sleeve, comprising

   - an inner body (20) having a center axis and

   - an outer body (10) having a center axis, which is coaxial relative to the center axis of the inner body,

   wherein the inner body (20) and the outer body (10) are connected in a firm and pressure-tight manner to one another in the region of their end faces while forming tension elements (24, 24'), and a means (18) is provided for applying pressure to the area of the outer body directed toward its center axis,
   characterized in that in the region between the tension elements (24, 24') the outer body (10) includes a material having a modulus of elasticity lower than that of the rest of the material of the outer body (10).
2. The clamp tool according to Claim 1, characterized in that the means for applying pressure to the area of the outer body (10) directed toward its center axis comprises at least one channel (18) provided in the inner body, which joins the area of the inner body (20) directed away from its center axis.
3. The clamp tool according to Claim 1, characterized in that in order to form tension elements (24, 24'), the outer body (10) is designed with a wall thickness greater in the region of its end face than in a central region.
4. The clamp tool according to Claim 1, characterized in that the region of greater wall thickness of the outer body (10) is designed as an annular flange, against which the end faces of the outer body rest.
5. The clamp tool according to one of Claims 1 through 4, characterized in that the outer body (10) has a variable wall thickness, at least in the axial direction.
6. The clamp tool according to Claim 1, characterized in that the material having a lower modulus of elasticity is epoxy resin.
7. A use of a clamping tool according to one of Claims 1 through 6 for producing a sleeve.
8. A system comprising a clamp tool according to one of Claims 1 through 7, and at least one sleeve, characterized in that the sleeve is made entirely of a castable material.
9. The system according to Claim 8, characterized in that the castable material is epoxy resin.
10. The system according to Claim 8 or 9, characterized in that the castable material is mixed with modulus of elasticity- and/or stiffness- and/or conductivity-enhancing, and/or weight-reducing fillers, in particular, glass fibers, glass bubbles, aramide fibers, carbon fibers, electrically conductive fibers and strip-like materials.
11. The system according to Claim 8, characterized in that the castable material is a metal or a metal alloy.
12. The system according to Claim 11, characterized in that the metal is aluminum or a nonferrous metal, such as copper.
13. The system according to Claim 8, characterized in that the sleeve has a conical or cylindrical inner profile.
14. The system according to Claim 8, characterized in that the sleeve has a variable wall thickness over its length, which is produced by a corresponding inner profile of the sleeve during the casting process.
15. A method for producing a sleeve, comprising the following steps:

    a) providing a production core having the features of a clamp tool according to one of Claims 1 through 7;

    b) expanding the production core to the desired inner dimension of the sleeve;

    c) enclosing the production core with an outer mold;

    d) casting the cavity between the production core and the outer mold with casting material, which is optionally mixed with fillers.

    e) curing the castable material; and

    f) eliminating the expansion of the production core.
16. The method according to Claim 15, in which the outer mold remains as an outer tube on the sleeve.
17. The method according to Claim 15 or 16, in which functional elements, such as identification chips, are introduced into the cavity between the production core and the outer mold.
18. The method according to one of Claims 15 through 17, in which a production core is provided, which has a wall thickness varying at least in the axial direction in such a way that, after expansion, an outer profile results, which ensures a bending compensation in a system comprising a clamp tool having a homogenous tension path and the finished sleeve.

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