WO2005032821A1

WO2005032821A1 - Composite shaft for printing cylinder, comprising hydraulic sleeve-fixing device

Info

Publication number: WO2005032821A1
Application number: PCT/ES2003/000509
Authority: WO
Inventors: Jordi PUIG i VILÁ; Jordi Sahun Peres; Pere Roger I Colom
Original assignee: Comexi, S.A.
Priority date: 2003-10-08
Filing date: 2003-10-08
Publication date: 2005-04-14
Also published as: ATE399643T1; DE60321975D1; EP1679189B1; EP1679189A1; AU2003274126A1; ES2309344T3

Abstract

The invention relates to a composite shaft for a printing cylinder, comprising a hydraulic sleeve-fixing device. The inventive shaft comprises first and second parts (10, 20) which define end installation and guiding means (11, 21) and respective coupling means (14, 24) which are inserted into the ends of a third tubular part (30) which defines an intermediary cylindrical portion (31) that is used to support sleeves (40). The above-mentioned hydraulic device comprises two expandable bushings (50) which are disposed on the first and second parts (10, 20) and which are each provided with an annular cavity (51). Said cavity is communicated with a longitudinal channel in the shaft which contains a fluid that can be pressurised in order to make an outer derformable wall (52) of the bushing convex. The aforementioned longitudinal channel comprises first and second portions (12, 22) in the first and second parts (10, 20), which are communicated by means of a flexible tube (60) which is housed in an inner cavity in the third part (30).

Description

COMPOSITE SHAFT FOR PRINT CYLINDER WITH HYDRAULIC SHIRT FIXING DEVICE

FIELD OF THE ART This invention concerns a composite shaft for a printing cylinder provided with a hydraulic sleeve fixing device that includes a reservoir for a pressurized fluid communicated with at least one pair of expandable sleeves due to the pressure against a inner surface of the shirt. The axis of the invention is useful in the field of printing in general and, more specifically, in the field of flexographic printing.

BACKGROUND OF THE INVENTION In the field of printing, for example, in flexography, printing rollers or cylinders adapted to carry outside a printing cliché or a frame are well known and used. Generally, the roller is composed of a steel shaft on which a clichés shirt or interchangeable hatched shirt is fixed. In order to hold the sleeve releasably on the shaft, several systems are known which generally use expandable elements associated with the outer surface of the shaft and capable of being deformed by a pressurized fluid in order to expand them against an inner surface of the sleeve. The pressurized fluid, for example, oil or grease, may be contained in a closed circuit within the shaft and a plunger device is capable of being operated from the outside to apply pressure to said fluid. A solid shaft is known, of a metallic material such as steel, with two end portions, staggered, which include installation and guidance configurations, and an intermediate, cylindrical portion for shirt support, which has an outer diameter adapted to adjust with the inside diameter of the shirts. In this axis, the hydraulic shirt fixing device is of the type comprising a pair of expandable sleeves located at respective ends of said intermediate portion. Each sleeve is provided with an internal annular cavity communicated with a longitudinal duct of the shaft filled with a fluid capable of being subjected to pressure and a deformable outer wall with an outer diameter equivalent, at rest, to said outer diameter of the intermediate portion. As a result of a deformation caused by the pressure of said fluid, the sleeve expands and its outer diameter becomes slightly larger than the outer diameter of the intermediate portion, and that the inner diameter of the jacket. A drawback of this type of construction is that the shaft, which is made of solid steel, is extremely heavy. In addition, the mechanization of the said longitudinal conduit, which is of a relatively small diameter and axially travels the axis from one end to almost the other, is a difficult and highly specialized task, and therefore of high cost. US-A-3378902 describes a detachable printing cylinder with hydraulic fixing means. The cylinder comprises a tubular roller and a pair of heads that close the opposite ends of said roller. These heads have central openings in which expandable collars are installed adapted to receive and fix an axis located coaxially with respect to the roller, protruding from both ends, beyond the heads, installation and guidance configurations of the axis. There is a hollow space between the outer surface of the shaft and the inner surface of the tubular roller. Each expandable collar includes a sleeve that fits on the shaft with a thick part that defines a hub in contact with the outer wall of the head and a section that can be pressurized delimited by a wall of reduced thickness deformable by pressure in contact with the outer surface From the axis. A ring surrounds said section capable of being pressurized and is fixed thereto to define together with said wall of reduced thickness a hydraulic fluid chamber in connection with a device to generate a releasable pressure mounted on the part defining the hub. The device comprises a small piston capable of being operated from the outside by acting on a headless screw to generate a pressure in the existing fluid in the hydraulic fluid chamber and thereby deforming the wall of reduced thickness to impose an immobilization force on the axis. A drawback of this construction is that to fix or release the roller to the axis is necessary to act individually on the existing collars at both ends of the roller.

BRIEF EXPOSURE OF THE INVENTION The foregoing and other drawbacks are overcome, in accordance with the present invention, by providing a composite shaft for printing cylinder with hydraulic shirt fixing device, of the type comprising two end portions, with installation and guidance configurations. , and an intermediate, cylindrical portion for shirt support, with an outer diameter adapted to fit the inner diameter of the shirts, and where said hydraulic shirt fixing device is of the type comprising a pair of expandable sleeves located in respective ends of said intermediate portion and each provided with an internal annular cavity communicated with a longitudinal conduit of the shaft for a fluid capable of being subjected to pressure and a deformable outer wall with an outer diameter equivalent, at rest, to said outer diameter of the intermediate portion and that, as a result of a deformation produced by r the pressure of said fluid is slightly greater than the outer diameter of the intermediate portion. The axis of the present invention is characterized in that said end portions are defined in first and second pieces each of which comprises a portion of said longitudinal conduit and on each of which one of said expandable sleeves is mounted in communication with the respective first or second portion of said longitudinal conduit through at least one radial conduit, said first and second parts comprising respective first and second coupling configurations adapted to fit the plug at ends of a third tubular part defining the portion intermediate, said first and second portions of the longitudinal conduit being communicated with each other by means of a flexible tube housed in a hollow interior of said third piece. The first and second pieces are preferably made of a metal, such as steel, and the third piece is of a relatively light carbon fiber composite. The first and second portions of the longitudinal duct, the flexible tube, the radial ducts, and the annular cavities together form a tightly sealed tank completely filled with said fluid capable of being subjected to pressure, and the first portion of the longitudinal duct has a mouth an outer end of the first piece and in said mouth a piston device capable of being actuated is installed for apply pressure to said fluid. This construction makes it possible to obtain a lighter printing cylinder with the same performance as a state-of-the-art cylinder with a solid shaft, and it is remarkably easier to manufacture, especially as regards the drilling of said longitudinal conduit, since it is formed here by two portions of short length, easy to drill, located in the corresponding first and second pieces, and completed with the flexible tube in the inner hollow of the third portion.

BRIEF DESCRIPTION OF THE DRAWINGS These and other advantages and features of the present invention will be better understood from the following detailed description of an exemplary embodiment with reference to the attached drawings, in which: Fig. 1 is a sectional view length of a solid shaft for printing cylinder with hydraulic sleeve fixing device according to the state of the art; Fig. 2 is a longitudinal sectional view of the composite shaft for printing cylinder with hydraulic sleeve fixing device according to an embodiment of the present invention; and Fig. 3 is a longitudinal sectional view of an enlarged detail of the axis of Fig. 1.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENT In Fig. 1 a solid shaft for printing cylinder with hydraulic sleeve fixing device according to the prior art is shown, which is composed of a solid piece 80, of a material metallic such as steel, which defines two end portions 81, 82, staggered, which include installation and guidance configurations, and an intermediate portion 83, cylindrical, which has an outside diameter adapted to fit with the inner diameter of the shirts. The hydraulic sleeve fixing device comprises a pair of expandable sleeves 90 located at respective ends of said intermediate portion 83. Each sleeve 90 is provided with an internal annular cavity 91 communicated through radial ducts 84 with a longitudinal duct 85 of the shaft . The inner annular cavities 91 of the sleeves 90 are externally delimited by deformable outer walls 92 of equivalent outside diameter, at rest, to said outer diameter of the intermediate portion 83. The longitudinal conduit 85 has a mouth at one end of the shaft and a blind end near the other end. The longitudinal conduit 85, the radial passages 84 and the cavities 91 form a reservoir filled with a fluid capable of being subjected to pressure under the actuation of a piston device 63 installed in the mouth of the conduit 85 and capable of being operated from the outside. by an appropriate tool. An increase in the pressure of the fluid in the chambers 91 by the actuation of the piston device 63 causes deformation or bulging in the deformable walls 92 of the sleeves 90, which press against the inner diameter of the sleeve 40, immobilizing it. This solid axis of the state of the art described in relation to Fig. 1 is extremely heavy and the longitudinal duct 85 is difficult and expensive to machine. Referring now to Figs. 2 and 3, there is shown the composite shaft for printing cylinder with hydraulic shirt fixing device, according to the present invention. The new axis is formed by first and second pieces 10, 20 which constitute end portions 11, 21 and a third piece 30, tubular, which constitutes an intermediate portion 31. The mentioned first and second pieces 10, 20 are solid parts, of a metal, such as steel, and end portions 11, 21 define installation and guidance configurations, such as, for example, seating for bearings or bearings, etc. Said third piece 30 is constituted by a tubular element of a light material, such as a carbon fiber composite material, and the first and second pieces 10, 20 define, at their respective opposite ends, respective first and second configurations of coupling 14, 24 adapted to fit the plug into the ends of the hollow interior of the third piece 30. The intermediate portion 31 is externally cylindrical, and is adapted to support a jacket 40 (shown by dashed lines in the figures) changeable. For this, the intermediate portion 31 has an outer diameter adapted to fit the inner diameter of the sleeves 40 allowing sliding of the sleeves 40 over the outer surface of the intermediate portion 31 in order to facilitate placement and removal. In fact, the intermediate portion 31 of the shaft is slightly longer than the piece 30 and includes middle parts of the respective first and second pieces 10, 20, where elements of the hydraulic shirt fixing device are described below, so that end portions of the jacket 40 are superimposed on said elements in the middle parts of the first and second pieces 10, 20. To fix a jacket 40 in position on the shaft, a hydraulic device itself is incorporated which includes a pair of expandable sleeves 50 located at respective ends of said intermediate portion 31, specifically on the middle parts of the first and second pieces 10, 20. Each of said expandable sleeves 50 is provided with a communicated inner annular cavity 51, through one or more radial ducts 13, 23, with a longitudinal duct 12, 22, 60 of the shaft. The annular cavities 51, radial ducts 13, 23 and longitudinal duct 12, 22, 60 together form a tightly sealed reservoir completely filled with a fluid capable of being subjected to pressure, such as an oil or grease. This annular cavity 51 is delimited by a deformable outer wall 52 having an outer diameter equivalent, at rest, to the inner diameter of the jacket 40. As a result of a deformation of the outer wall 52 caused by an increase in the pressure of the existing fluid in said longitudinal duct 12, 22, 60, the outer diameter of the outer wall 52 becomes slightly larger than the inner diameter of the jacket 40 and, as a consequence, the jacket 40 is immobilized on the shaft. The longitudinal duct 12, 22, 60 runs practically from end to end of the shaft and is formed by three portions. A first portion 12 of Longitudinal duct is formed by a through hole that axially crosses the first piece 10 with openings at both ends thereof, a second portion 22 of the longitudinal duct is formed by a blind hole formed axially in the second piece 20 and open at the inner end thereof, and a third, intermediate portion, is formed by a flexible tube 60 housed in a hollow interior of said third piece 30 and communicates with each other the first and second portions 12, 22 of the longitudinal conduit formed in the first and second pieces . The flexible tube 60 is connected at its ends to the openings of the first and second portions 12, 22 of the longitudinal conduit located at the respective internal ends of the first and second pieces 10, 20 by means of two splicing devices 61, 62. Thus, said closed tank is constituted by the first and second portions 12, 22 of the longitudinal duct, the flexible tube 60, the radial ducts 13, 23, and the annular cavities 51. At the mouth of the first portion 12 of the open longitudinal duct in the outer end of the first piece 10 is installed a piston device 63, of the conventional type, capable of being operated from the outside by means of a tool for applying pressure to said fluid, or for relaxing said pressure. With this, by means of a single operation, both expandable sleeves 50 located at opposite ends of the intermediate zone 31 are actuated to fix or release the sleeve 40. The second portion 22 of the longitudinal duct has a blind end inside the second piece. 20, and a radial passage 26 that communicates the second portion 22 of the longitudinal duct, near said blind end, with the outside. In this radial passage 26 a purge valve 64 is installed. In another radial passage 15, which connects the first portion 12 of the longitudinal conduit of the first piece 10 with the outside, an inlet valve 65 is used which is used for the introduction of the fluid inside the tank. It is evident that the radial passages 15, 26, as well as the purge valves 64 and inlet 65, could be located in different positions with the same result. The second piece 20 has a portion adjacent to the second coupling configuration 24 with an outside diameter greater than the outer diameter of the second coupling configuration 24, defining a step 25 that provides a stop for a second end of the third piece 30. This larger diameter portion also provides an outer supporting surface for the other of the expandable sleeves 50. The outer diameter of the first coupling configuration 14 is the maximum diameter of the first piece 10, so that the third tubular piece 30 can be inserted from the end of the shaft corresponding to the first piece 10 passing over it until the second end of the third piece 30 is coupled to a plug in the second coupling configuration 24 until it stops in said step 25. On an intermediate part of the first piece 10, adjacent to the first coupling configuration 14, an adapter sleeve 70 is mounted which provides a stop for the first end of the third piece 30, pinning it between the first and second pieces 10, 20. P remarkably, this adapter sleeve 70 is strongly fixed, for example, hot-rolled (by thermal expansion), on the first piece 10, and the inner surface of the ends of the third piece 30 is joined, for example, by adhesion, to the outer surfaces of the first and second coupling configurations 14, 24. The adapter sleeve 70 also provides an outer support surface for the other of the expandable sleeves 50, and includes one or more holes 72 coinciding in position and diameter with the mouth or the mouths of the one or more radial ducts 13, such that said hole 72 and at least a portion of the radial duct 13 together define a threaded threaded hole in which a sleeve 66 having the function of being threaded is inserted. seal the radial duct 13 in the joint between the adapter sleeve 70 and the first piece 10. Also, the adapter sleeve 70 includes a hole 71 coincides with the mouth of the radial passage 15 to provide access to said inlet valve 65. In order to facilitate the introduction and removal of the sleeves, the third piece 30 and possibly the expandable sleeves 50 comprise an outer layer of coating of a material Low coefficient of friction. Alternatively, the third piece 30 comprises an outer coating layer of a metallic material, preferably steel, which brings together the characteristics of low coefficient of friction and high wear resistance required. It should also be noted that according to another exemplary embodiment not shown, the composite shaft only includes an expandable sleeve 50 at one end of the intermediate portion 31 for fixing the sleeve 40. Preferably, this single expandable sleeve 50 is in the middle part of the first piece 10, in which case the longitudinal duct is formed only by the first portion 12, which has a blind inner end in the first piece 10, and the second portion 22 of the longitudinal duct is omitted in the second piece 20 and the flexible connection tube 60. However, in some applications it may be necessary that the only expandable sleeve 50 be in the middle part of the second part 20, in which case the longitudinal conduit will be formed, as in the case with two sleeves shown in Figs. 2 and 3, for the first and second portions 12, 22 in the first and second pieces 10, 20 and the flexible connection tube 60 between them both in the hollow interior of the third piece. The above examples of embodiment have a purely illustrative and non-limiting nature, and one skilled in the art will be able to introduce numerous modifications and variants without departing from the scope of the present invention as defined by the appended claims.

Claims

1.- Composite shaft for printing cylinder with hydraulic sleeve fixing device, of the type comprising two end portions (11, 21), with installation and guidance configurations, and an intermediate portion (31), cylindrical, for support sleeves (40), with an outer diameter adapted to fit the inner diameter of the sleeves (40), and wherein said hydraulic sleeve fixing device is of the type comprising a pair of expandable sleeves (50) located at respective ends of said intermediate portion (31) and each provided with an internal annular cavity (51) communicated with a longitudinal conduit (12, 22, 60) of the shaft containing a fluid capable of being subjected to pressure and a deformable outer wall (52 ) with an outer diameter equivalent, at rest, to said inner diameter of the jacket (40) and slightly larger, under deformation caused by the pressure of said fluid, than the inner diameter of the jacket (40), characterized in that said end portions (11, 21) are defined in first and second pieces (10, 20) which also include respective first and second coupling configurations (14, 24) adapted to fit the plug at ends of a third tubular piece (30) defining, at least in a greater part, the intermediate portion (31), where the longitudinal duct comprises first and second portions (12, 22) formed respectively in the first and second pieces (10, 20) and communicated with each other by means of a flexible tube (60) housed in a hollow interior of said third piece (30), and wherein said expandable sleeves (50) are each mounted on one of the first and second pieces ( 10, 20) and in communication with the respective first or second portion (12, 22) of the longitudinal conduit through at least one radial conduit (13, 23).

2. Axis, according to claim 1, characterized in that the outer diameter of the first coupling configuration (14) is the maximum diameter of the first piece (10), and on a portion adjacent to the first coupling configuration ( 14) an adapter sleeve (70) is mounted which provides a stop for a first end of the third piece (30) and an outer support surface for one of the expandable sleeves (50).

3. Axis, according to claim 2, characterized in that the second piece (20) has a portion adjacent to the second coupling configuration (24) of outer diameter greater than the outer diameter of the second coupling configuration (24) , defining a step (25) that provides a stop for a second end of the third piece (30) and an outer support surface for the other of the expandable sleeves (50).

4. Axis, according to claim 3, characterized in that the first and second portions (12, 22) of the longitudinal duct have openings at respective internal ends of the first and second pieces (10, 20) and said flexible tube ( 60) is connected at its ends to said openings of the first and second portions (12, 22) of the longitudinal duct by means of two splicing devices (61, 62).

5. Axis, according to claim 4, characterized in that the first and second portions (12, 22) of the longitudinal duct, the flexible tube (60), the radial ducts (13, 23), and the annular cavities (51 ) together form a tightly sealed container completely filled with said fluid capable of being subjected to pressure, and the first portion (12) of the longitudinal duct has a mouth an outer end of the first piece (10) and in said mouth is installed a piston device (63) capable of being actuated to apply pressure to said fluid.

6. Axis, according to claim 5, characterized in that the second portion (22) of the longitudinal duct has a blind end inside the second piece (20), and a radial passage (26) in which it is installed a purge valve (64) that communicates the second portion (22) of the longitudinal duct near said blind end with the outside.

7. Axis, according to claim 5, characterized in that the first piece (10) comprises a radial passage (15) that communicates the first portion (12) of the longitudinal conduit with the outside, and in said radial passage (15) an inlet valve (65) for the introduction of the fluid is installed.

8. Axis, according to claim 7, characterized in that said adapter sleeve (70) includes a hole (71) coinciding with the mouth of the radial passage (15) to provide access to said inlet valve (65).

9. Axis, according to claim 2, characterized in that said adapter sleeve (70) includes at least one hole (72) coinciding with the mouth of the radial duct (13), which is at least one, and of equal diameter, said hole (72) and at least a portion of the radial duct (13) jointly defining a threaded threaded hole in which a sleeve (66) for sealing a joint between the adapter sleeve (70) and the first is threaded piece (10).

10. Axis, according to claim 2, characterized in that said adapter sleeve (70) is hot-drawn on the first piece (10).

11. Axis, according to claim 1, characterized in that the third piece (30) is made of a carbon fiber composite.

12. Axis, according to claim 11, characterized in that the third piece (30) comprises an outer layer of coating of a material of low coefficient of friction and high wear resistance.

13. Axis, according to claim 11, characterized in that the third piece (30) comprises an outer coating layer of a metallic material selected from a group that includes steel.

14. Axis, according to claim 11, characterized in that the expandable sleeves (50) comprise an outer coating layer of a low friction coefficient material.

15.- Composite shaft for printing cylinder with hydraulic sleeve fixing device, of the type comprising two end portions (11, 21), with installation and guidance configurations, and an intermediate portion (31), cylindrical, for support sleeves (40), with an outer diameter adapted to fit the inner diameter of the sleeves (40), and wherein said hydraulic shirt fixing device is of the type comprising an expandable sleeve (50) located at one end of said portion intermediate (31) and provided with an internal annular cavity (51) communicated with a longitudinal duct (12) of the shaft containing a fluid capable of being subjected to pressure and a deformable outer wall (52) with an outer diameter equivalent, at rest, to said inner diameter of the jacket (40) and slightly larger, under deformation caused by the pressure of said fluid, than the inner diameter of the jacket (40), characterized in that said end portions (11, 21) they are defined in first and second pieces (10, 20) which also include respective first and second coupling configurations (14, 24) adapted to fit the plug at the ends of a third tubular part (30) defining, at least for the most part, the intermediate portion (31), wherein said longitudinal duct (12) comprises a blind axial duct in the first piece (10) and wherein said expandable sleeve (50) is mounted on a middle part of the first piece ( 10) in communication with said longitudinal conduit (12) through at least one radial conduit (13).

16.- Composite shaft for printing cylinder with hydraulic sleeve fixing device, of the type comprising two end portions (11, 21), with installation and guidance configurations, and an intermediate portion (31), cylindrical, for supporting sleeves (40), with an outer diameter adapted to fit the inner diameter of the sleeves (40), and wherein said hydraulic sleeve fixing device is of the type comprising an expandable sleeve (50) located at one end of said portion intermediate (31) and provided with an internal annular cavity (51) communicated with a longitudinal duct (12, 22, 60) of the shaft containing a fluid capable of being subjected to pressure and a deformable outer wall (52) with an equivalent outer diameter , at rest, at said inner diameter of the jacket (40) and slightly larger, under deformation caused by the pressure of said fluid, than the inner diameter of the jacket (40), characterized in that said po Extreme portions (11, 21) are defined in first and second pieces (10, 20) which also include respective first and second coupling configurations (14, 24) adapted to fit the plug at the ends of a third part (30 ) tubular defining, at least in a greater part, the intermediate portion (31), where the longitudinal duct comprises first and second portions (12, 22) formed respectively in the first and second pieces (10, 20) and communicated between yes by means of a flexible tube (60) housed in a hollow interior of said third piece (30), and said expandable sleeve (50) is mounted on the second piece (20) and in communication with the respective second portion (22) of the longitudinal conduit through at least one radial conduit (23).