A SLEEVE FOR A BRIDGE MANDREL, AND A BRIDGE MANDREL AND SLEEVE ASSEMBLY

Abstract

A substantially tubular interchangeable sleeve is adapted for applying a printing or coating liquid to a substrate material or offset roller. The sleeve has a multi-layer construction primarily consisting of a first outer layer of a dimensionally stable substantially fluid-impregnable solid material, such as aluminum or steel, around the exterior surface of which is affixed or applied a print or coating liquid receiving plate or layer. The sleeve further comprises one or more further interior layers of relatively less dimensionally stable, compressible, usually fibrous materials disposed inwardly of the interior surface of the first layer which, under air pressure, can be compressed so as to enlarge the inner dimensions of the sleeve so that it can be slid over a suitable bridge mandrel. The sleeve further comprises at least one end ring of a dimensionally stable substantially fluid-impregnable solid material.

Claims

1-19. (canceled)

20. A substantially tubular sleeve having a longitudinal axis adapted for applying a printing or coating liquid to a substrate material or offset roller, said sleeve having a multi-layer construction primarily consisting of a first outer layer of a dimensionally stable substantially fluid-impregnable solid material around the exterior surface of which is affixed or applied a printing ink or coating liquid receiving plate or layer, and at least one second layer of a relatively less dimensionally stable compressible material disposed inwardly of the interior surface of the first layer, wherein the sleeve further comprises: at least one end ring of a dimensionally stable substantially fluid-impregnable solid material, said end ring comprising first and second body portions, one body portion being disposed radially to the outside of the other, one of said body portions being received within a rebate provided in an end radial surface of said first outer layer and retained therein by means of mating engagement between a substantially axially aligned surface of said end ring body portion and a correspondingly aligned surface of said rebate such that the alternate end ring body portion substantially overlies an end surface of the second inner layer so as to prevent fluid ingress into the compressible material through said end surface of said inner layer.

21. A sleeve according to claim 20, wherein the rebate provided in the first layer is one of: provided along and around its inner circumferential edge so that the axial engagement surface provided by such rebating faces radially inwardly of said first layer; and provided as an annular channel within an axially outermost radial surface of said first layer.

22. A sleeve according to claim 21, wherein the end ring first body portion is disposed radially outwardly of the second body portion, and said end ring comprises a flange portion which extends radially outwardly from first body portion so as to substantially cover the remaining radial end surface of the first layer disposed radially to the outside of the rebate therein.

23. A sleeve according to claim 20, wherein the first body portion provides an axial engagement surface which matingly engages the with a corresponding axial engagement surface of the rebate.

24. A sleeve according to claim 20, wherein the body portion of the end ring which substantially overlies the radial end surface of the inner layer does so in a manner which completely covers said inner layer radial surface.

25. A sleeve according to claim 20, wherein the engagement surfaces of both rebate and the first or second body portion of the end ring are one or both of: axially aligned with the longitudinal axis of the sleeve; and parallel with the longitudinal axis of the sleeve.

26. A sleeve according to claim 20, wherein the mating engagement between the engagement surfaces of the rebate and the first or second body portion of the end ring are one of: threaded in that the relevant body portion of the end ring is essentially screwed into the rebate of the first layer, and interferingly fitted to one another.

27. A sleeve according to claim 20, wherein the sleeve comprises two end rings, one provided at either end thereof.

28. A sleeve according to claim 20, wherein one or more O-ring seals are provided in at least one of: the mating engagement surfaces on the relevant first or second body portion of the end ring and the rebate, and the seam formed between a flange portion of the end ring and a corresponding radial end surface of the tube.

29. A sleeve according to claim 20, comprised of the following substantially tubular layers, in radially increasing order: a fiberglass base wrap layer; a compressible layer of one of: a polymer, foamed and/or cellular composition; a composite build up layer; a substantially dimensionally stable fluid-impregnable metallic layer, being one of aluminum or steel; and a coating layer, being one of: Chromium Oxide and a ceramic.

30. A sleeve according to claim 20, wherein the end ring is constituted primarily or exclusively of one of: aluminum, steel, anodized aluminum, and anodized steel.

31. A sleeve according to claim 20, wherein the rebate is provided along and around its outer circumferential edge so that the axial engagement surface provided by such rebating faces radially outwardly of said first layer, and wherein the end ring first body portion is disposed radially outwardly of the second body portion which takes the form of a flange portion which extends radially inwardly from said first body portion so as to substantially cover the remaining radial end surface of the first layer disposed radially inwardly of the rebate, and also the radial end surface of the second layer provided on the inside of the first layer which would otherwise be exposed.

32. A sleeve according to claim 20, further including a print or coating liquid receiving layer applied to the sleeve such that said print or coating liquid receiving layer effectively covers a circumferential seam formed between an axially innermost radial surface of the flange portion of the end ring, and the outermost radial surface first layer with which it is mates when end ring is fully secured to said first layer.

33. A sleeve according to claim 32, wherein the radially outermost edges of the sleeve ends are chamfered.

34. A sleeve according to claim 33, wherein the chamfer surface is defined partially or completely by any one or more of: the first layer; the print or coating liquid receiving layer; and the end ring.

35. A sleeve according to claim 21, further including a print or coating liquid receiving layer applied to the sleeve such that said print or coating liquid receiving layer effectively covers a circumferential seam formed between an axially innermost radial surface of the flange portion of the end ring, and the outermost radial surface first layer with which it is mates when end ring is fully secured to said first layer.

36. A sleeve according to claim 35, wherein the radially outermost edges of the sleeve ends are chamfered.

37. A sleeve according to claim 36, wherein the chamfer surface is defined partially or completely by any one or more of: the first layer; the print or coating liquid receiving layer; and the end ring.

38. A sleeve according to claim 20, wherein an innermost axial surface of the end ring is dimensioned so that it is disposed one of: radially outwardly and radially inwardly, of the innermost surface of the second layer so that a shoulder is defined in the interior cylindrical surface of the sleeve, by, respectively, an exposed annular radial surface of the second layer, or an exposed annular radial surface of the end ring.

39. An assembly comprising the sleeve of claim 38 and a mandrel, wherein said mandrel is provided with a corresponding shoulder provided in its substantially cylindrical outer surface and which the shoulder of the sleeve comes into abutting relation with to prevent further axial travel of the sleeve relative to the mandrel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 shows an exploded perspective view of one end of a sleeve according to the invention, together with an end ring adapted for screw fit into said end,

[0049] FIGS. 2 and 2A show schematic exploded sectional elevations through alternate embodiments of a bridge mandrel and a sleeve adapted to be slidingly received thereover, and

[0050] FIGS. 3 and 4 show schematic sectional elevations of respective alternate embodiments of one end of a sleeve with an end ring secured therein.

DETAILED DESCRIPTION

[0051] Referring firstly to FIG. 1, there is shown a perspective view of a sleeve and corresponding end ring according to the invention and indicated generally at 2 and 4 respectively. An open end 6 of the sleeve is illustrated prior to screw-fitting insertion of the end ring 4 therein to facilitate understanding of the design specifics of the particular sleeve end 6. In general, the sleeve 2 is of generally tubular construction, and in practically all circumstances, the sleeve will be geometrically cylindrical (although other cross-sections are certainly possible and should be considered as encompassed herein). The primary structural component of the sleeve itself is an annular aluminum or steel tube 8 (which in FIG. 1 is not shown with any coating or printing plate layer yet applied or affixed to the exterior surface for clarity, but which is in practice is commonly required). The open end 6 of the tube 8 is internally rebated which: [0052] enlarges the internal diameter of the tube in the end region, [0053] reduces the wall thickness of the tube in the end region, and [0054] defines an internal shoulder at some short (typically of the order of 5-25 mm) distance axially inside the tube remote from the open end 6.

[0055] Thus, after internal rebating, an outermost radial annular surface 10 is provided which defines an opening which receives a correspondingly shaped and sized tubular shank portion 12 of the end ring 4, and axially inwardly of the open end 6, there is provided a shoulder 14 which an outer portion of the end-most radial planar surface of said end ring shank portion 12 preferably ultimately abuts as the said shank portion is fully received in the sleeve open end 6. The rebating process also further defines an axial inner surface 16 in the sleeve open end, and as is shown in FIG. 1, screw thread formations 18 are ideally provided in the axially innermost region of said axial inner surface 16, and corresponding screw threads 20 are provided towards the free axial end of the shank portion 16 on the outermost axial surface thereof. By such means, not only can the end ring 4 be received within the open end 6 of the tube 8, but it can be exceedingly firmly secured therein.

[0056] As may also be seen in FIG. 1, the end ring 4 is provided with a peripheral flange 22 which effectively enlarges the outermost diameter of the end ring in its axially outermost region, an most preferably, dimensionally, said flange 22 is exactly the same diameter as that of the outermost radial annular surface 10 so that, once the end ring is fully received and screwed into the open end 6, said flange abuts said radial annular surface 10 in planar mating fashion and thus defines a barely visible seam therebetween.

[0057] In terms of the interior of the tube 8, as is common for expandable sleeves, multiple further layers are provided around the innermost axial cylindrical surface of the tube, and in FIG. 1, three such layers are referenced at 30, 32, 34. Although for sleeves adapted for certain specific applications, there may be more or less, but in accordance with the invention, and to render the sleeve internally expandable to at least some degree, at least one such layer must be formed from a material which is relatively dimensionally much less stable than the aluminum (or steel) of which the sleeve itself is primarily constructed.

[0058] Specifically, in this embodiment, layer 30, the innermost layer, is known as the base wrap layer, and is commonly of a fiberglass-type material, or in some cases, a glass (or other) fiber reinforced plastics or polymer material. To the radially cylindrical surface of layer 30 is then provided a compressible layer 32, and to the radially outer surface thereof is provided further layer 34, commonly known as a composite build-up layer, and it is the radially exterior-most cylindrical surface of this layer which interfaces with the innermost axial surface of the tube 8.

[0059] Referring now to FIG. 2, in which a sectional elevation of an assembled sleeve 8 with end ring 4 screwingly disposed in the formerly open end 6 is illustrated, the various layers 30, 32, 34 are provided inside the tube 8 such that their annular radial end surfaces (visible in FIG. 1) are in substantially co-planar with the annular radial surface of shoulder 14. Additionally in this FIG. 2, a further coating layer 36 is shown having been chemically or mechanically applied or affixed to the exterior axial cylindrical surface of the tube 8. Most preferably, the coating will be a Chromium Oxide coating as is known in the art, and will be thermally or chemically applied after the end rings are securely fixed to either end of the tube 6 so that a portion of said coating layer covers the axial end surfaces of the flange portion 22 (22A for end ring 4A at the opposite end of the tube 8 from end ring 4) and thus covers the seam formed between the flange portions 22, 22A and the respective radial surfaces 10 (10A) of the tube 8 with which they mate. Of course, in alternative configurations, the coating may be replaced by, or may be provided on, a cylindrical printing plate mechanically affixed around said exterior surface of the tube 8, but in either case it is preferred that the said seam is covered, for reasons specifically described below.

[0060] It can also be seen in FIG. 2 that when respective threaded portions 18, 20 on tube inner axial surface 16 and end ring shank 12 respectively are fully engaged, and the end ring is thus completely received and securely fixed within tube open end. In this arrangement, a number of important mechanical interactions are achieved: [0061] flange 22 of the end ring matingly engages with the annular radial surface 10 of the tube in a seam which provides a first barrier to liquid ingress, [0062] the shank portion 12 of the end ring is dimensioned and designed so that a first portion comes into mating abutting relation with the internal shoulder 14 of the tube, and a second portion (radially inwardly of the first portion) comes into mating abutting relation with at least one, preferably two or more, of the inner layers 30, 32, 34 so that the radial end surfaces of such layers are effectively covered and capped (which are most preferably co-planar with the radial surface of the shoulder 14), thus providing a yet further barrier to liquid ingress into such surfaces, and [0063] the path that any liquid would need to travel before reaching the radial end surfaces of the covered and capped inner layers 30, 32, 34 is tortuous in that it would involve two right-angled turns, specifically, it would need to seep in through the seam defined between end ring flange portion 22 and tube outermost radial end surface 10, turn through 90 in a first axially inward direction at axially outermost region of the end ring shank portion 12, and then again through 90 to flow in a radial direction along the axial innermost radial surface of the end of said end ring shank portion before coming into contact with the radial surfaces of any of the inner layers, 30, 32, 34.

[0064] Thus by carefully designing and dimensioning both tube 8 and end ring 4, the resulting sleeve can be not only structurally very robust, but also practically impregnable to liquid.

[0065] One further feature of the invention not specifically illustrated is the possible provision of one or more O-ring seals provided at one or more positions along the seam formed between the end ring flange (or body portion(s)) and the corresponding adjacent surface of the tube radial end surface 10 (or the axial engagement surfaces formed by the rebate). Those skilled in the art will immediately understand the additional benefit that such O-ring seals will provide as far as liquid ingress and travel within said seam is concerned.

[0066] Although screw thread formations are described above as providing the mechanical connection between end ring 4 and tube 6, it is certainly contemplated that other mechanical connections are possible, such as, for example, interferingly fitting the end ring within the open end of the tube 6.

[0067] It is also to be noted in FIG. 2 that further preferred features of the invention are shown. Specifically, the internal diametral dimensions of one (or both) of the end rings 4 (4A) are carefully chosen so as to leave an exposed internal annular shoulder 40, most preferably being (radially) only a portion of the innermost layer 30, but in other embodiments, the shoulder 40 may be defined entirely by the innermost layer 30, or it may be defined by the innermost layer 30 and a part of the layer 32. Regardless of how and by which particular layer said shoulder might be defined, its purpose is to render the sleeve 2 handed as regards a mandrel 50 over which it is adapted to be slid, and to which it is ultimately secured, most preferably by interference fit as previously mentioned. Although FIG. 2 is schematic in that it shows the sleeve 2 exploded for clarity, in practice, the innermost axial surface of the innermost layer 30 mates with an exterior cylindrical surface 52 of said mandrel, and most preferably the far end 54 of mandrel 50 (being that end which is effectively inaccessible to an operative wishing to extract either sleeve or mandrel from the print machinery in which they are mounted) is further provided with a collar 56 which is axially the same length as the end ring 4 and of the same height as the radial thickness of shoulder 40 so that the sleeve can only be completely slid over the mandrel and properly disposed thereon only if the sleeve is correctly orientated, that is with the end in which end ring 4 is disposed being fed over the mandrel first. At the alternate end of the mandrel, where end ring 4A is provided, a similar arrangement is also provided, though in this case the innermost diametral dimension of the end ring is less than the innermost diametral dimension of the innermost layer 30 so that an internal shoulder 60 is defined by the axially innermost radial surface of the shank portion 12A of that end ring. A free end 58 of the mandrel 50 is shown rebated around its exterior surface so as to provide a corresponding shoulder 62 which comes into abutting mating relation with the shoulder 60, such only being capable of being achieved when the sleeve is attempted to be fitted to the mandrel in the correct orientation. Thus with end rings 4, 4A having openings of slightly different diameters, and the mandrel itself having collar 56 and a rebate provided around its front end 58, different portions of the sleeve provide different clearanced fits around corresponding different portions of the mandrel.

[0068] A yet further preferred feature of the invention is illustrated in FIG. 2, particularly as regards the seam formed between the flange portions 22, 22A of the end rings, and the outermost radial end surfaces 10, 10A of the tube which forms the mandrel. As can be seen for end ring 4, the outermost edges of the flange portions 22 are preferably chamfered off in a manner which results in any one or more of the following: [0069] the seam formed between flange portion 22 and tube outermost radial surface 10 being included within the chamfer, [0070] the chamfer surface being comprised of only a part of the flange portion 22 (22A) of the end ring 4 (4A), and a part of coating layer 36 (or printing plate), and [0071] the chamfer surface being comprised only of the coating layer 36 (or printing plate) so that the underlying seam betwixt flange portions 22 (22A) and tube axially outermost radial surfaces 10 (10A) is entirely concealed and thus effectively sealed off by said coating layer 36 (or printing plate).

[0072] Such arrangements provide yet further improved resistance to liquid ingress into the seam.

[0073] Referring briefly to FIG. 2A, an alternative embodiment is illustrated in which the mandrel 50 is provided only with a rebate around its free end 58 (i.e. without collar 56 as illustrated in FIG. 2) so as to define only a single shoulder 62 which comes into abutting mating relationship with the shoulder 60 defined in the end ring 4A, provided of course that the sleeve 2 is in the orientation shown in FIG. 2A. In both the embodiments shown in FIGS. 2 and 2A, if the sleeve orientation were reverse, then it would be impossible to slide the sleeve over the mandrel beyond the shoulder 62 because the interior diameter of the end ring 4A is less than that of the cylindrical surface 52 of said mandrel. Additionally, it can be seen in FIG. 2A that the sleeve 2 may still be provided with an exposed shoulder 40 of layer 30, and in certain embodiments, the collar 56 provided on the far end 54 of the mandrel (FIG. 2) may be replaced with an annular gasket or O-ring seal (not shown) of a thickness which both permits the innermost axial surface of end ring 4 to slide thereover, and additionally provides a seal therewith to prevent fluid ingress into the otherwise exposed radial surface of layer 30, i.e. the shoulder 40. Regardless of whether a gasket or O-ring of this type is provided, one reason for retaining the exposed shoulder 40 is to provide a means for operatives to quickly identify which end of the sleeve is which, and thus correctly orientate the sleeve prior to any attempt to slide the sleeve over the mandrel.

[0074] Referring finally to FIGS. 3 & 4, alternate assembly configuration is illustrated whereby the end rings 4C, 4D respectively may be secured to and within the radial end surfaces 10C, 10D of tubes 8C, 8D. In FIG. 3, the rebate is provided in and around the exterior axial surface of the tube 8C, and the end ring 4C takes the form of a cap which is screwed onto the tube 8C by means of corresponding threads provided in both an axial inner surface of an end ring web portion 5C and an axial outer surface 9C in an end region of said tube. In this embodiment, end ring 4C is provided with a radially inwardly extending flange portion 22C which is shown in mating relation with the otherwise exposed radial end surfaces of inner layers 30C, 32C, 34C so as to effectively cover them and thus prevent ingress of liquid therein. Coating layer 36C is again applied after connecting the end ring 4C to the tube 8C, again effectively concealing the radial seam defined between the end ring and the outermost radial end surface 10C of the tube 8C. Dotted line 38 provides an indication of how the sleeve may be chamfered, as previously described.

[0075] In FIG. 4, the rebate is provided as an annular groove or channel within the thickness of the outermost radial surface of tube 8D, and again the end ring 4C takes the form of a cap having an annular tongue formation 4E which is screwed into said rebate by means of corresponding threads provided on one or both axial surfaces of said tongue formation, and in one or both axial inner surfaces of the annular groove or channel. Also in this embodiment, end ring 4D is provided with a radially inwardly extending flange portion 22D which, as above, is shown in mating relation with the otherwise exposed radial end surfaces of inner layers 30C, 32C, 34C. Coating layer 36D is again applied after connecting the end ring 4D to the tube 8D, again effectively concealing the radial seam defined between the end ring and the outermost radial end surface 10D of the tube 8D. Dotted line 38 again provides an indication of chamfer orientation.

[0076] In all embodiments therefore, the end ring is very securely mechanically affixed to the tube end, and the end ring and sleeve are together carefully designed and dimensioned such that a part of the end ring effectively covers and caps (at least partially) the otherwise exposed radial end surfaces of the inner layers 30, 32, 34 which are most commonly of a more absorbent material than that of which the tube 8 is constructed.

[0077] In summary therefore, a substantially tubular interchangeable sleeve adapted for applying a printing or coating liquid to a substrate material or offset roller is disclosed. The sleeve has a multi-layer construction primarily consisting of a first outer layer of a dimensionally stable substantially fluid-impregnable solid material, such as aluminum or steel, around the exterior surface of which is affixed or applied a printing ink or coating liquid receiving plate or layer. The sleeve further comprises one or more further interior layers of relatively less dimensionally stable, compressible usually fibrous materials disposed inwardly of the interior surface of the first layer which, under air pressure, can be compressed so as to enlarge the inner dimensions of the sleeve so that it can be slid over a suitable bridge mandrel. The sleeve further comprises at least one end ring of a dimensionally stable substantially fluid-impregnable solid material. The end ring comprises first and second body portions, one being disposed radially to the outside of the other, so that when one of said body portions is received within a rebate provided in a radial end surface of the first outer layer and retained therein by means of mating engagement between a substantially axially aligned surface of the end ring body portion and a correspondingly aligned surface of the rebate, the alternate end ring body portion partially or completely overlies one or more of the radial end surfaces of interior layers so as to prevent fluid ingress into that or those layers. An assembly of such a sleeve and a bridge mandrel on which it may be mounted is additionally described.