Bridge sleeves with diametrically expandable stabilizers

A bridge sleeve has at each extreme end of the bridge sleeve, a multi-component stabilizer. One component of each stabilizer includes an inner cylindrical contacting surface having a diameter that changes as this respective component of the stabilizer moves axially relative to at least one other component of the respective stabilizer.

CROSS REFERENCE TO RELATED APPLICATIONS

FIELD OF THE INVENTION

The present invention relates to bridge sleeves (aka carrier sleeves, aka adapter sleeves) that themselves can be air mounted to the mandrel of a printing machine in the flexographic, offset or rotogravure printing field and that permit air mounting of a printing cylinder onto the bridge sleeves.

BACKGROUND OF THE INVENTION

Assuming that the outside diameter of the rotary mandrel of a printing machine in the flexographic, offset or rotogravure printing field is concentric with the mandrel's axis of rotation, then as the rotational speed of the print sleeve that is mounted on that mandrel increases, maintenance of adequate print quality increasingly depends on maintaining a fixed and invariable radial distance between the outside diameter of the rotary mandrel and the inside diameter of the print sleeve. If this radial distance varies, then print quality degrades. One type of degraded print quality takes the form of lightly inked or un-inked portions of the image alternating with darkly inked portions of the image. Another type of degraded print quality arises when portions of the image contain too much ink so as to decrease the desired resolution of that portion of the image on the substrate that advances past the printing surface of the print sleeve.

Variation in this desired fixed and invariable radial distance can occur if the print sleeve is subject to vibration as the print sleeve and the mandrel rotate. Such variation in the fixed and invariable radial distance can arise when an asymmetric printing surface of the print sleeve causes uneven pressure to be applied to the print sleeve, and this uneven pressure in turn causes a vibrational resonance effect to be transmitted to the bridge sleeve that results in the bridge sleeve becoming out of round as the print sleeve and the mandrel rotate. Such variation in the fixed and invariable radial distance can also occur for example due to the rotational inertia that acts on the bridge sleeve at very high run speeds and causes the bridge sleeve to become out-of-round as the print sleeve and the mandrel rotate.

In the flexographic, offset or rotogravure printing field, in order to increase the circumference of the printing surface without increasing the diameter of the rotary mandrel, it is known to use a bridge sleeve that is disposed between the outside cylindrical (or conical) surface of a rotary mandrel of the printing machine and the inside cylindrical (or conical) surface of an actual print sleeve, which carries on its outer cylindrical surface the data and/or images that are to be printed. The use of a bridge sleeve such as disclosed in commonly owned U.S. Pat. No. 5,782,181, which is hereby incorporated herein in its entirety for all purposes, enables various print developments to be achieved with the same rotary mandrel, without the need to replace this latter (generally of steel and hence heavy or of carbon fiber and hence costly) following a change in print development compared with the previous work carried out on the same printing machine.

However, a bridge sleeve that fails to serve as a rigid concentric attachment between the outside diameter of the rotary mandrel and the inside diameter of the print sleeve will fail to maintain a fixed and invariable radial distance between the outside diameter of the rotary mandrel and the inside diameter of the print sleeve and so result in the types of unsatisfactory print quality described above.

Various methods are known for mounting a conventional bridge sleeve (defined by a hollow cylinder with a through hole) onto a rotary mandrel of a printing machine. While mounting systems employing hydraulics and mounting systems employing mechanical connections are known, these typically are more cumbersome and heavier than a much used “air mounting” system that employs a conventional bridge sleeve that has an inner core layer, which though the inner core layer is slightly expandable in the radial direction, under atmospheric conditions the inner core layer defines an inner surface diameter slightly smaller than the diameter of the outer surface of the mandrel. The difference between these diameters enables an interference fit to be achieved between the mandrel of the printing machine and the conventional bridge sleeve. Positioning the conventional bridge sleeve at one end of the mandrel, compressed air is supplied (by known methods) between the outer surface of the mandrel and the inner surface of the bridge sleeve. The compressed air expands the diameter of the inner surface of the conventional bridge sleeve sufficiently to allow the bridge sleeve to slide over a cushion of air, a so-called air bearing, onto the outer surface of the mandrel. When the supply of compressed air is ended, the diameter of the inner surface of the conventional bridge sleeve shrinks sufficiently to allow the inner surface to grip the outer surface of the mandrel in an interference fit between the mandrel and the conventional bridge sleeve. Similarly, by again feeding compressed air onto the mandrel surface (by known methods), the inner surface of the conventional bridge sleeve can be slightly expanded to enable the conventional bridge sleeve to be released from the interference fit and removed from the mandrel.

Air-mountable bridge sleeves such as disclosed in commonly owned U.S. Pat. Nos. 5,819,657; 6,688,226; and 6,691,614, each of which being hereby incorporated herein in its entirety for all purposes, is usually made with a multi-layer body comprising a rigid outer cylinder made of carbon fiber and a cylindrical inner layer with an inner cylindrical surface that defines a bore with the diameter that is slightly smaller than the diameter of the outer surface of the mandrel. This type of conventional air-mounted bridge sleeve also includes at least one elastically compressible and radially deformable layer running the length of the bridge sleeve, and this compressible layer can be disposed against the outer cylindrical surface of the bridge sleeve's cylindrical inner layer. The compressed air acting against the inner surface of the inner layer of such a conventional bridge sleeve compresses this elastically compressible and radially deformable layer, which can be made of polyurethane foam for example, to enable the inner surface of the inner layer of the bridge sleeve to expand radially as it is being mounted on the outer surface of the mandrel.

However this elastic characteristic of the compressible layers of these air-mounted bridge sleeves works at cross purposes with the need for the bridge sleeve's outer surface to remain as rigidly fixed as possible with respect to the mandrel of the printing machine in order to resist the vibrations that are generated during operation of the modern printing machines that operate at very high run speeds. When the mandrel of such a printing machine rotates at speeds necessary to advance the substrate through the printing machine at line speeds of more than about 250 meters/minute, the non-uniform forces applied by the asymmetric printing surfaces of printing plates and/or the presence of the elastically compressible and radially deformable layer in a conventional bridge sleeve result(s) in machine vibrations that cause radial displacements of the bridge sleeve's outer surface with respect to the mandrel. These radially-directed displacements are transmitted to the printing surface of the print sleeve that is carried by the bridge sleeve, thereby causing the print sleeve to bounce against the substrate in rhythm with the vibrations instead of maintaining constant pressure contact with the substrate to be printed. The bouncing of the print sleeve against the substrate to be printed causes the printed image to include alternating regions where the image is printed darker than it should be followed by a region where the image is printed lighter than it should be printed. This bouncing also can cause some regions of the image to be too heavily inked and lose the desired resolution of the image. Accordingly, when these radial displacements of the bridge sleeve resulting from non-uniform pressures applied by the asymmetric surfaces of print sleeves and/or the deformation of the compressible layer do(es) arise, they compromise print quality to an unacceptable level by causing the type of banding or skipping described above to result from the bouncing of the print sleeve against the substrate.

These unacceptable radial displacements of the air-mounted bridge sleeve with compressible layers are more likely to arise as the sleeve's length and/or diameter increases. Nonetheless, printing machines that generate line speeds exceeding 250 meters/minute are becoming the norm, and a need exists for air-mountable bridge sleeves that produce acceptable print quality. Indeed, printing machines that generate line speeds exceeding 1,200 meters/minute are being put into service. Thus, as print line speeds increase and/or the diameters of the bridge sleeve must be increased in order to accommodate the larger print repeats that are needed to perform various print jobs, these air-mounted bridge sleeves requiring a lengthwise compressible layer fail to serve as a rigid concentric attachment between the outside diameter of the rotary mandrel and the inside diameter of the print sleeve.

Moreover, the elastically compressible and radially deformable layer running the length of the conventional bridge sleeve eventually degrades under even normal usage of a conventional bridge sleeve at lower line speeds below 250 meters/minute. Once this elastically compressible and radially deformable layer degrades, the entire bridge sleeve becomes useless and must be discarded, notwithstanding the continued viability of the remaining components such as the outer carbon fiber cylinder.

To eliminate the compressible layer (with its undesirable effects) of the air-mounted bridge sleeves, hydraulic systems have been developed for mounting bridge sleeves to the mandrel of a flexographic printing machine. One such hydraulic system for mounting a bridge sleeve on the rotary mandrel has been developed by Fischer & Krecke of Germany. This is an hydraulic system that requires a specially configured mandrel that has a smaller diameter on the operator side than on the motor side of the mandrel. The bridge sleeve has two end heads on which are mounted a carbon fiber cylinder. One end head defines a larger inner diameter that will fit over the larger diameter portion of the outer surface of the mandrel, and the other end head defines a smaller inner diameter that is nonetheless slightly larger than the smaller diameter portion of the outer surface of the mandrel at the operator end of the mandrel. At each end of the mandrel there is an expandable ring, the diameter of which expands and contracts according to the introduction or withdrawal of incompressible grease that is hydraulically used to expand or contract the rings. Each of these rings expands to contact the inner diameter of the steel insert at each end of a carbon fiber tube that forms the bridge sleeve.

Windmoeller Hoelscher of Germany has a mechanism that is similar to the Fischer & Krecke mechanism. The problem with each of these mechanisms is of course that as the rings expand and contract with usage, the rings become fatigued and their expansion eventually occurs non-uniformly so that they are not round relative to the central axis of the mandrel. Thus, over time the bridge sleeve rotates asymmetrically with the rotational axis of the mandrel, and this produces a bouncing motion of the bridge sleeve that causes the print quality to deteriorate as described above for the air-mounted bridge sleeves with the compressible layers. This deterioration is exacerbated as the speed of the web to be printed increases until the print quality is deemed unacceptable. Examples of unacceptable print quality include the presence of bands in the printed image that result from the bounce of the bridge sleeve as the rings that contact the inside diameter of the bridge sleeve no longer expand uniformly in perfect concentricity with the axis of rotation of the mandrel.

Another mechanical system for mounting a bridge sleeve on a rotary mandrel was developed by Paper Converting Machine Corporation of Green Bay, Wis. and is described in U.S. Pat. No. 6,647,879. In this PCMC system, the bridge sleeve has opposed hubs on which are mounted a carbon fiber cylinder. The internal diameter of each of these hubs is expanded and contracted by a semi-circular collar that has one end pivotally connected to its respective hub and the opposite end connected to its respective hub via an eccentric cam that opens and closes a pivoting clamp of the collar so that the inside diameter of the collar can be expanded and contracted by movement of the eccentric cam, which is connected to an external hex nut that can be turned to tighten the collar onto the mandrel or loosen the collar from the mandrel.

However, one drawback to this PCMC system is the steel-to-steel contact between the inside diameter of the collar and the outside diameter of the rotary mandrel. Whenever this bridge sleeve is slid onto the mandrel, there inevitably is some damage to the exterior surface of the mandrel by contact with the inside diameter of the collar. Moreover, due to the steel-to-steel contact between the inside diameter of the collar of each hub and the outside diameter of the mandrel, whenever there is a machine malfunction that results in a web wrap up event that prevents further advancement of the web being printed, the steel inside diameter of the collar will rotate with respect to the outside diameter of the mandrel. This metal-to-metal relative rotation mars the outside diameter of the mandrel by the involved steel-to-steel scraping. As much as a three inch circumferential scrape in the outside diameter of the mandrel can be anticipated by such events, requiring re-machining and repair of the mandrel at the expense of both the mandrel repair and the cost of the lost downtime of the printing machine.

Another disadvantage of this PCMC system is the fact that when the diameter of the bridge sleeve must be increased, a commensurate increase in the size of the hubs results in a significant increase in the weight of the bridge sleeve. Government workplace rules typically limit the weight of the bridge sleeve to no more than 50 pounds. Still another drawback to this PCMC system is the fact that the earn eventually starts to wear with use. Such wear then causes the collar to become loose and move with respect to the stabilizer. These movements cause the bridge sleeve to lose concentricity with the mandrel, which results in the bounce that causes deterioration of the print quality as described above. These unacceptable effects due to movement of the collar become more noticeable as the speed of rotation of the bridge sleeve increases and/or as the diameter and/or length of the bridge sleeve increases.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention. Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.

One embodiment of the present invention includes an improved bridge sleeve with a rigid stabilizer at each opposite end of the sleeve that diametrically expands using compressed air for easy mounting of the sleeve onto the printing machine's mandrel. Another embodiment of the improved bridge sleeve of the present invention need not include the elastically compressible and radially deformable layer running the entire length of the conventional bridge sleeve. This improved bridge sleeve of the present invention nonetheless exhibits sufficiently high rigidity so as not to deform unacceptably during its use on the printing machine that is running line speeds as high as 1,200 meters per minute.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar features.

It is to be understood that the ranges and limits mentioned herein include all sub-ranges located within the prescribed limits, inclusive of the limits themselves unless otherwise stated. For instance, a range from 100 to 200 also includes all possible sub-ranges, examples of which are from 100 to 150, 170 to 190, 153 to 162, 145.3 to 149.6, and 187 to 200. Further, a limit of up to 7 also includes a limit of up to 5, up to 3, and up to 4.5, as well as all sub-ranges within the limit, such as from about 0 to 5, which includes 0 and includes 5 and from 5.2 to 7, which includes 5.2 and includes 7.

References to the axial refer to the lengthwise direction in which the cylindrical sleeve or mandrel or annulus or ring elongates along an axis of rotation. References to the radial refer to the transverse direction in which the cylindrical sleeve or mandrel or annulus or ring extends outwardly or inwardly in a perpendicular direction relative to the axis of rotation. References to the circumferential refer to the tangential direction with respect to the cylindrical surface of the sleeve or mandrel or annulus or ring. A reference to the diameter of a surface refers to the diameter of the circle that defines the intersection of the surface with a plane that is normal to the axis of rotation of the surface. The meaning of additional reference terms will become apparent through their usages in the text that follows.

FIG. 1schematically depicts an elevated view of an exemplary embodiment of a bridge sleeve30of the present invention. This bridge sleeve30is shown in relation to a mandrel40of a printing machine (not shown) and in relation to a print sleeve41. As schematically shown inFIG. 1, the mandrel40has a journal42or43at each opposite end that is axially aligned about the central axis of rotation of the mandrel40. The so-called motor journal42is received in the printing machine and is located farthest away from the operator when the printing machine is in use. While the so-called operator journal43is on the end of the mandrel40that is closest to the operator when the printing machine is in use. As is conventional, the so-called motor end of the mandrel40has a registration pin44extending radially from the outer surface45of the mandrel40near where the motor end of the mandrel40defines an annular shoulder141that is present on many modern mandrels40.

As shown inFIGS. 1,2and13D for example, the so-called motor end of the bridge sleeve30has a registration notch31that receives therein, the registration pin44of the mandrel40when the bridge sleeve30is properly aligned on the mandrel40. The dashed line designated31ainFIG. 1schematically indicates the alignment of the registration notch31with the registration pin44as the bridge sleeve30moves in the mounting direction schematically indicated by the arrow designated200aonto the mandrel40. The dashed line designated30ainFIG. 1schematically indicates the axial center line and axis of rotation of the bridge sleeve30and would coincide with the axis of rotation of the mandrel40.

As is conventional in the art and schematically shown inFIG. 1, the so-called operator end of the mandrel40desirably can be provided with a plurality of air holes46through which compressed air can be supplied to the outer surface45of the mandrel40from a supply47of pressurized air that can be associated with the printing machine or can be available in the facility that houses the printing machine. Though not visible in the scale of the drawing ofFIG. 1, the air holes46at the operator end of the mandrel40desirably can be arranged in a circumferentially extending groove that promotes circumferentially even distribution of the compressed air to the outer surface45of the mandrel40.

The bridge sleeve30of the present invention can be configured so that using only the pressurized air that is supplied to the mandrel40, the bridge sleeve30can be alternately air-mounted onto the mandrel40and dismounted from the mandrel40. Alternatively, the bridge sleeve30can be configured for connection to a separate supply of compressed air from the pressurized air that is supplied through the mandrel40, and this separate supply of compressed air can be used to mount or dismount the bridge sleeve30onto the outer surface45of the mandrel40.

As shown inFIG. 2, the outer surface35of the bridge sleeve30is defined by the cylindrical outer surface of the rigid outermost layer37of the bridge sleeve30. This rigid outermost layer37of the bridge sleeve30desirably is defined by a carbon fiber composite material that is rigid, light in weight and desirably at least as strong as steel. The carbon fiber in this rigid outermost layer37of the bridge sleeve30desirably is oriented parallel to the rotational axis of the bridge sleeve30and provides the rigid outermost layer37with maximum rigidity.

The bridge sleeve30desirably includes a stabilizer51,52disposed near each opposite end of the bridge sleeve30. Each stabilizer51,52is provided with an inner contacting surface58by which the particular stabilizer51or52comes into contact with the outer surface45of the mandrel40. Moreover, in accordance with one aspect of the present invention, the stabilizers51,52can be actuated so that together they provide a rigid, concentric attachment and support between the outer surface45of the rotary mandrel40and the inner surface48of the print sleeve41(FIG. 2) that is mounted on the outer surface35of the bridge sleeve30. However, in order to be able to mount and dismount the bridge sleeve30to and from, respectively, the mandrel40, a mechanism is provided to expand the diameter of the inner contacting surface58of each stabilizer51,52sufficiently to permit the bridge sleeve30to slide axially over the outer surface45of the mandrel40without contact between the outer surface45of the mandrel40and the inner contacting surface58of each stabilizer51,52. The variance in the diameter of the inner contacting surface58of each stabilizer51,52desirably can range between slightly less than the diameter of the outer surface45of the mandrel40of the intended printing machine and a diameter that is about 0.4 millimeters larger than the diameter of the outer surface45of the mandrel40of the intended printing machine. Larger diametric ranges for this variance in the diameter of the inner contacting surface58of each stabilizer51,52also can be accommodated. The inclusion of these rigid stabilizers51,52assures that the radial distance between the bridge sleeve's rigid outer surface35, which can be formed of a carbon fiber cylinder, and the equally rigid outer surface45(typically composed of steel) of the mandrel40of the printing machine remains unvarying and constant, even at line speeds in excess of 1,200 meters per minute.

An embodiment of a first stabilizer51that desirably is disposed near the motor end of an embodiment of a bridge sleeve30is shown with its components in a disassembled state inFIG. 4, in which portions of some of those components have been cut away to better reveal and facilitate description of certain of their features. The first stabilizer51(aka motor end stabilizer51) is disposed at the end of the bridge sleeve30that is first slid onto the operator end of the mandrel40having the air holes46when the bridge sleeve is being mounted onto the mandrel40. An embodiment of a second stabilizer52(aka operator end stabilizer52) that desirably is disposed near the operator end of an embodiment of a bridge sleeve30is shown with its components in a disassembled state inFIG. 3, in which portions of some of those components have been cut away to better reveal and facilitate description of certain of their features.

An end-on plan view of the motor end of the bridge sleeve30depicted inFIG. 2is shown inFIG. 6with the components of the first stabilizer51in their assembled arrangement. Similarly, an end-on plan view the operator end of the bridge sleeve30depicted inFIG. 2is shown inFIG. 5with the components of the second stabilizer52in their assembled arrangement. A view from a plane passing through the central axis of rotation30aof the bridge sleeve30depicted inFIG. 2is shown inFIGS. 7A and 8Awith the components of the two stabilizers51and52in their assembled arrangement. InFIG. 7A, the stabilizers51and52are shown with their various components oriented as they would be when the bridge sleeve30is purged of any pressurized air such as when the bridge sleeve30has been removed from the mandrel40. InFIG. 8A, the stabilizers51and52are shown with their various components oriented as they would be when the motor end of the bridge sleeve30is advanced onto the operator end of the mandrel40sufficiently to be receiving pressurized air (schematically indicated by the arrows) from the air holes46of the mandrel40that pressurizes the stabilizers51,52but before the pressurized air reaches and expands the radially expandable cylindrical inner core38of the bridge sleeve30.

As shown inFIGS. 3 and 4, each respective stabilizer51,52includes an outer shell53and an inner shell54that is configured to nest at least partially within the outer shell53. The outer shell53and the inner shell54of each of the stabilizers51,52desirably is formed of rigid incompressible material such as steel or carbon fiber composite material. The outer shell53of the first stabilizer51desirably is configured almost identically as is the outer shell53of the second stabilizer52, and both outer shells53desirably are composed of aluminum that is hard anodized and yet is light in weight. As shown inFIGS. 2 and 13Afor example, the main difference between the two outer shells53is the provision of an air release valve that can be activated by pressing a pin86extending from the operator end stabilizer52to release pressurized air from the air circuit that activates the stabilizers51,52. The number and arrangement of the axially extending holes by which the respective annular end cap81,82is attached to the outwardly facing edge of the outer shell53also can differ as between the outer shell53for the first stabilizer51and the outer shell53for the second stabilizer52.

Though only visible in the view of the first stabilizer51inFIG. 4, each outer shell is provided with six axially extending air passages105or89arranged at 60 degree intervals around the circumference of the outer shell53. As schematically shown inFIGS. 7A and 8Afor example, three air passages89arranged at 120 degree intervals form part of the separate pressurized air circuit that is devoted to conveying pressurized air to the holes36(not shown in the cross-section taken inFIGS. 7A and 8A) through the outer surface35of the bridge sleeve30to mount and dismount the print sleeve41from the surface35of the bridge sleeve30. As schematically shown inFIGS. 7A and 8Afor example, the separate pressurized air circuit conveying pressurized air to the holes36also includes axially extending hollow tubes75that connect the air passages89in the outer shell53of the first stabilizer51to the air passages89in the outer shell53of the second stabilizer52. This pressurized air circuit is configured to provide pressurized air to the air holes36(FIGS. 1 and 2) at the outer surface35of the bridge sleeve30to create a thin air bearing of pressurized air between the inner surface48of the print sleeve41and the outer surface35of the bridge sleeve30. This air bearing of pressurized air slightly expands the diameter of the inner surface48of the print sleeve41(FIG. 1) so that the print sleeve41can slide just above the outer surface35of the bridge sleeve30and thereby alternately become air-mounted onto or removed from the outer surface35of the bridge sleeve30. This thin layer of pressurized air that forms the co-called air bearing enables the operator to slide the print sleeve41axially in the direction schematically indicated inFIG. 1by the arrow designated200buntil the print sleeve41envelops the outer surface35of the bridge sleeve30. When the supply47of pressurized air is discontinued, the air layer disappears, the diameter of the inner surface48of the print sleeve41contracts to the diameter of the outer surface35of the bridge sleeve30and thus tightly grips the outer surface35of the bridge sleeve30in a manner that prevents both relative axial movement and circumferential movement between the print sleeve41and the bridge sleeve30under normal operating conditions of the printing machine.

As schematically indicated inFIG. 1, the bridge sleeve30is further configured so that air-mounting the print sleeve41onto the outer surface35of the bridge sleeve30can be accomplished with either a flow-through air-mounting system or a piped air-mounted system. As schematically shown inFIGS. 7A,8A,13A and14A for example, a so-called piped embodiment of the bridge sleeve30can be configured with an air portal78for connection to a separate supply of compressed air from the pressurized air that is supplied through the mandrel40. As schematically indicated inFIG. 1, this separate supply of compressed can be connected to the air portal78of the bridge sleeve30via a fitting34that automatically is connected to the air portal78when the bridge sleeve30is mounted on the mandrel and aligned with the registration pin44of the mandrel40. As schematically shown inFIGS. 7A,8A,13A and14A, the air portal78can be connected via a conduit95to axial air passages89in the outer shell53of the motor stabilizer51. Once so connected, the pressurized air can be piped via axial air passages89in the outer shell53through the bridge sleeve30, axially and radially, and expelled via the holes36(FIGS. 1 and 2) through the outer surface35of the bridge sleeve30and thus used to mount the print sleeve41onto the outer surface35of the bridge sleeve30and alternately dismount the print sleeve41from the outer surface35of the bridge sleeve30.

Alternatively, a so-called flow-through embodiment of the bridge sleeve30can be configured so that the pressurized air that is supplied through the mandrel40flows radially through the bridge sleeve30and to the outer surface35of the bridge sleeve30and is used to mount the print sleeve41onto the outer surface35of the bridge sleeve30. Because air flow through mounting circuits for bridge sleeves are known, they will not be further described here.

The bridge sleeve30desirably includes two separate pressurized air circuits that receive pressurized air from a source outside of the bridge sleeve30. The three air passages105shown schematically in the view of the first stabilizer51inFIG. 4are arranged at 120 degree intervals and form part of the second separate pressurized air circuit that is devoted to conveying pressurized air to actuate the stabilizers51,52as explained more fully below.

The inner shell54of each of the stabilizers51,52desirably is formed of resilient spring steel. For example, each inner shell54desirably is formed of 90 kg drawn steel sheet that has been tempered. However, in alternative embodiments of the stabilizers51,52, it is desirable to form the inner shell54of carbon fiber composite material so that the diameter of the inner contacting surface58is equal to the diameter of the outer surface45of the mandrel40, whereupon if necessary a very fine abrasive can be used against the inner contacting surface58to remove only enough material from the inner contacting surface58until the inner contacting surface58easily slides over the outer surface45of the mandrel40during mounting and dismounting of the bridge sleeve30onto and from the mandrel40.

As shown inFIGS. 3 and 11for example, the inner shell54is defined in part by a section that has conically shaped surface56. As shown inFIG. 3for example, the opposite the conically shaped surface56, the inner shell54defines a cylindrically shaped surface that is the inner contacting surface58of the inner shell54. As shown inFIG. 11for example, there is a tongue and groove surface61on the exterior of one end68of the inner shell54. As shown inFIGS. 3 and 4for example, the inner shell54of each of the stabilizers51,52desirably is composed of a plurality of sections54bthat are joined together at adjacent axially extending edges with an elastic adhesive such as a polymeric adhesive. The MERBENIT brand permanently elastic adhesive and sealant available from Antala Industria, S.L. of Barcelona, Spain provides a suitable polymeric adhesive for connecting the individual steel sections54bthat once joined together form the inner shell54. The distance between each pair of the adjacent axially extending edges of the separate sections54bof the inner shell54defines a slot57that is filled with the elastic adhesive that connects the adjacent sections54bof the inner shell54. Each slot57between the adjacent sections54bcomprising the inner shell54desirably extends the entire axial length of the inner shell54. Given the dimensions of an inner shell54that is serviceable for bridge sleeves30suitable for a large percentage of printing machines now in use, the inner shell54desirably comprises twenty sections54bof equal size. However, it also is possible to use ten sections that are formed so that each section is twice the size in the circumferential direction as one of the twenty sections54band is divided by a central slot57that does not pass completely through the centerline of the ten section embodiment and ends at the tongue and groove surface61of the inner shell54. In the ten section embodiment, the elastic adhesive fills the central slot as well as the slots57between each of the adjacent ten sections. In any case, any excess elastic adhesive is removed so that both the conical surface56and the inner contacting surface58of the inner shell54are smooth.

As shown inFIGS. 4,9,9A and10for example, each inner shell54has defined through one of its sections, an oblong opening54athat has the longer dimension of the oblong opening54aoriented parallel to the axial center line30a(FIG. 2) of the bridge sleeve30. As shown inFIG. 9Afor example, projecting radially outwardly from the inner surface55of the outer shell53is a set screw53athat projects up into the oblong opening54aand acts as a guide for the axial movement of the inner shell54relative to the outer shell53. The set screw53aalso could be positioned to project in a direction that was normal to the inner conical surface55of the inner shell. The set screw53adesirably can have one threaded end that can be screwed into a threaded hole defined in the outer shell53. The sizing, shape and orientation of the oblong opening54aconstrains the movement of the inner shell54relative to the outer shell53when the set screw53ais surrounded by the oblong opening54a.

In an embodiment depicted inFIGS. 9 and 11for example, the outer shell53is fixed with respect to the rigid outermost layer37of the bridge sleeve30. As shown inFIG. 9for example, the recessed outer surface122of the outer shell53can be connected to the inner cylindrical surface124of the rigid carbon fiber outer layer37. In the embodiments shown inFIGS. 9 and 11the inwardly facing end of the outer shell53is shown to be directly connected (as by adhesive) to one end of the cylindrical rigid outer cylindrical layer37of the bridge sleeve30. Thus, the outer shell53is sometimes referred to as the rigid holder body or the main body because it rigidly carries and holds one end of the rigid outermost layer37of the bridge sleeve30. In an embodiment depicted inFIGS. 9 and 11for example, the outermost cylindrical surface35of the outer shell53desirably is co-extensive with the cylindrical outer surface35of the rigid outermost layer37of the bridge sleeve30to form the outer surface35of the bridge sleeve30.

Likewise, each outer shell53desirably is permanently connected (as by adhesive) to one end of the radially expandable cylindrical inner core38of the bridge sleeve30. As shown inFIGS. 9 and 11for example, a compressible layer39desirably is disposed between the end of the outer surface of the inner core38and the recessed inner surface126of the outer shell53of each stabilizer51,52. As shown inFIGS. 3 and 4for example, the outer shell53defines an axially extending inner cavity that is partially defined by a rigid inner surface with a section defining an inner conical surface55. As shown inFIGS. 9 and 11for example, the inner conical surface55of the outer shell53desirably has a diameter that increases as one moves inwardly away from the end of the outer shell53where the outer shell53is connected to the radially expandable inner core38of the bridge sleeve30.

Unlike the outer shell53, the inner shell54of each stabilizer51,52is not fixed with respect to either of the inner core38or the rigid outer layer37of the bridge sleeve30. Nor is the inner shell54of each stabilizer51,52fixed with respect to the outer shell53. As shown inFIGS. 9 and 11for example, the inner shell54is defined in part by a section that has conically shaped surface56in a manner that complements the shape of the inner conical surface55of the outer shell53and is disposed to butt and slide against the inner conical surface55of the outer shell53. Thus, the outer conical surface56of the inner shell54of each stabilizer51,52nests within the inner conical surface55of the outer shell53and thus is axially, moveably received within the respective axially extending inner cavity of the respective rigid outer shell53.

As shown inFIGS. 9 and 10for example, the section of the inner shell54that has the conical outer surface56defines a plurality of slots57that extend completely through the inner shell54from the conical surface56through the inner contacting surface58that defines a portion of the inner bore that extends axially completely through the bridge sleeve30. In the embodiments shown inFIGS. 9 and 10for example, each slot57extends axially from the inward-facing edge59of the inner shell54that defines the narrower free end of the conical surface56and desirably extends completely through the opposite edge68. However, as described above, all but one of the slots57desirably are filled with elastic adhesive, and one slot57is left unfilled for purposes of facilitating installation of the inner shell54into the outer shell53during assembly of the stabilizers51,52.

In the embodiments shown inFIG. 11for example, there is a tongue and groove surface61on the exterior of one end68of the inner shell54. This tongue and groove surface61receives a complementary tongue and groove surface62on the interior surface of an annular piston60so that the annular piston60can be connected onto the inner shell54and mechanically attached thereto to form a combined integral structure. However, the two tongue and groove surfaces61,62are joined in a slip fit that permits some small relative movement in the radial direction between the inner shell54and the annular piston60, but little if any axial relative movement between the inner shell54and the annular piston60. Thus, axial movement of the annular piston60necessarily drags the inner shell54axially in the same direction as the axial movement of the annular piston60and vice-versa. But the inner shell54can move slightly in the radial direction while the annular piston60does not move with the inner shell54in the radial direction.

Each annular piston60desirably is formed of 90 kg drawn steel sheet that has been tempered. In the embodiments shown inFIGS. 9,10,11,12and20for example, each annular piston60desirably is provided with an air capture groove90extending circumferentially around the entire annular piston60and beneath the inner surface93thereof at the end of the annular piston60opposite where the tongue and groove surface62is configured. As shown inFIGS. 9 and 11for example, a circumferential groove63is configured in the exterior surface of the annular piston60that faces an opposing surface of the outer shell53. As shown inFIGS. 3,4,9and11for example, this circumferential groove63is configured to receive a pressure sealing ring64. This pressure sealing ring64is desirably formed from a combination of rubber as in a conventional pressure sealing O-ring and material such as polytetrafluoroethylene that lends some rigidity to the ring64, which is not radially deformable when supported in the circumferential groove63. As shown inFIGS. 9 and 11for example the pressure sealing ring64has a square transverse shape. This pressure sealing ring64creates a seal against the escape of air past where the pressure sealing ring64slides against a first opposing surface of the outer shell53.

As shown inFIGS. 3,4,9and11for example, there is a circumferentially extending groove71with a square-shaped transverse cross-section71defined in the interior section of the outer shell53. This circumferential groove71is disposed adjacent where the annular piston60contacts the outer shell53and receives a complementarily shaped pressure sealing ring74having a smaller diameter but otherwise like the pressure sealing ring64described above. This pressure sealing ring74similarly creates a seal against the escape of air past where the pressure sealing ring74slides against an exterior surface of the annular piston60.

In the embodiments shown inFIGS. 3,4,9and11for example, each of the stabilizers51,52desirably includes a resiliently flexible biasing member, such as a flat ring spring50, and a respective end cap81,82, which desirably is formed as an annular ring member. In the embodiments shown inFIGS. 4 and 9for example, a motor end cap81forms part of the motor end stabilizer51, while as similarly shown inFIGS. 3 and 11for example, an operator end cap82forms part of the operator end stabilizer52. As shown inFIG. 13Dfor example, the registration notch31is defined in a portion of the inner surface of the motor end cap81. As shown inFIGS. 3,4,5and6for example, each of the end caps81,82is rigidly connected to its respective outer shell53by a plurality of threaded bolts80. As shown inFIG. 13Cfor example, the threaded end of each bolt80passes through a bore83that extends axially through the respective end cap81,82and into a threaded hole84defined axially into the outwardly facing free edge69of the outer shell53so that the respective end cap81,82can be bolted onto the outer shell53and mechanically attached thereto to form a combined integral structure. Thus, once bolted to the outer shell53, the respective end cap81,82necessarily remains fixed in position with respect to the outer shell53and provides a backstop against axial movement of inner circumferential end of the flat ring spring50.

As shown inFIGS. 9 and 11for example, the flat ring spring50is disposed in an annular space that is defined between the inwardly facing end85of the respective end cap81,82and the outwardly facing side65of the respective annular piston60. The flat ring spring50thus tends to bias the annular piston60and integrally connected inner shell54in the axial direction toward the axial center of the bridge sleeve30so that the conical surface56of the inner shell54slides against the conical surface55of the outer shell53. Because each outer shell53remains immovable with respect to its respective end cap81,82, the slots57of the inner shell54must narrow to accommodate the axial movement of the inner shell54away from the flat ring spring50and toward the conical surface55of the outer shell53with the result that the diameter of the inner contacting surface58of the inner shell54becomes diminished. The normal gap between the opposed walls defining each of the slots57of the inner shell54in an unstressed state is depicted inFIGS. 10 and 12for example. However, the relatively narrowed gap between the opposed walls defining each of the slots57of the inner shell54is depicted inFIGS. 9 and 11.

The assembly of each of the stabilizers51,52proceeds in the same fashion, which now will be described, and desirably precedes the attachment of the radially expandable cylindrical inner core38and the rigid outermost layer37to the two stabilizers51,52of the bridge sleeve30. Referring toFIGS. 4 and 9for example, assembly of the embodiment of the first stabilizer51depicted therein proceeds by initially installing the pressure sealing ring74into the groove71in the outer shell53. The pressure sealing ring64is inserted into the groove63in the annular piston60. Leading with the tongue and groove surface62on the interior surface of the annular piston60, the annular piston60is inserted into the outer shell53from the outwardly facing free edge69of the outer shell53. Then the flat ring spring50is placed against the outwardly facing side65of the annular piston60, and the end cap81is bolted onto the outwardly facing free edge69of the outer shell53to back stop the flat ring spring50that biases the axial position of the annular piston60toward the center of the bridge sleeve30. The sections54bof the inner shell54are glued together except for the last two opposing edges, which are left unattached so that the inner shell54can be inserted into the outer shell53from the inwardly facing free edge79of the outer shell53. The inner shell54is inserted into the outer shell53leading with the tongue and groove surface61on one end of the inner shell54. The tongue and groove surface61of the inner shell54is hooked into the complementary tongue and groove surface62on the interior of the annular piston60. The inner shell54and annular piston60are rotated so that the oblong opening54athrough the inner shell54is aligned with the threaded opening through the outer shell53that receives the set screw53a. Whereupon the set screw53ais screwed into the threaded opening in the outer shell53from within the inner shell54. Now the two complementarily shaped conical surfaces55,56of the respective shells53,54touch one another.

As schematically shown inFIGS. 7A and 7B, because the diameter schematically designated D3of the inner surface93of annular piston60is larger than the diameter of the outer surface45of the mandrel40schematically designated D1, it is possible for the operator to slide enough of the motor end of the bridge sleeve30onto the operator end of the mandrel40so that the air pressure holes46in the outer surface45of the mandrel40reach the air capture groove90of the annular piston60in the motor end stabilizer51.

The bridge sleeve30desirably includes a pressurized air circuit that receives pressurized air from a source outside of the bridge sleeve30and is configured to actuate the expansion mechanisms that expand the diameter of the inner contacting surface58of the inner shell54of each of the stabilizers51,52so that the bridge sleeve30alternately can be air-mounted onto or removed from the mandrel40. The air capture grooves90of the annular pistons60of the stabilizers51,52form the entrance openings to the pressurized air circuit that receives pressurized air from a source outside of the bridge sleeve30to actuate the stabilizers51,52. Each ofFIGS. 7A and 7Bdepicts a cross-sectional view of the motor end of a bridge sleeve30positioned before reaching the entrance opening90to the pressurized air circuit that actuates the diametric variation of the inner contacting surfaces58of the inner shells54of the stabilizers51,52becomes positioned in communication with the air holes46through the outer surface45at the operator end of the mandrel40. Each ofFIGS. 8A and 8Bdepicts a cross-sectional view of the motor end of a bridge sleeve30while the entrance opening to the pressurized air circuit that actuates the diametric variation of the inner contacting surfaces58of the inner shells54of the stabilizers51,52becomes positioned in communication with the air holes46through the outer surface45at the operator end of the mandrel40while the pressurized air is being supplied through the mandrel40to the air holes46.

Each ofFIGS. 9 and 11is an enlarged detailed view of part of the motor end and operator end respectively, taken fromFIG. 7Aat a time just before the pressurized air is supplied through the mandrel40. InFIG. 1for example, the arrow designated200aschematically illustrates the direction in which the bridge sleeve30is being moved onto the stationary mandrel40by an operator. As shown in each ofFIG. 9, the air capture groove90formed in the inner surface93of the annular piston60has not yet aligned with the air pressure holes46in the outer surface45of the mandrel40. Note that in the operational state depicted inFIGS. 9 and 11, the flat ring spring50is configured at its minimal state of compression so that the axial distance between the inwardly facing end85of the end cap81and the outwardly facing side65of the annular piston60is at its maximum distance. As shown inFIG. 9, the diameter of the inner surface93of the annular piston60is wide enough so that the gap that exists between the outer surface45of the mandrel40and the inner surface93. This gap permits enough clearance so that the inner surface93of the annular piston60slides easily over the outer surface45of the mandrel40for a distance that is sufficient to enable the operator to position the air capture groove90directly in alignment with the air pressure holes46in the outer surface45of the mandrel40.

As shown inFIG. 9, the annular piston60of the first stabilizer51at the motor end of the bridge sleeve30defines an internal valve chamber100that has one end in fluid communication with an exit opening92. The exit opening92is in fluid communication with and empties into an air pressure plenum94that is defined between the annular piston60and the outer shell53and extends circumferentially around the entire first stabilizer51. The opposite end of the internal valve chamber100is conically shaped with the narrowest diameter portion in direct fluid communication with the air capture groove90through an angled entrance passage91. Furthermore, a one-way valve is disposed within this internal valve chamber100. The one-way valve is configured to admit air into the internal valve chamber100and the air pressure plenum94and prevent escape of air from the internal valve chamber100and the air pressure plenum94. As schematically shown inFIG. 9, the one-way valve desirably can be provided in the form of a check valve that has a ball101and a spring102, which biases the ball101against a relatively narrower diameter portion of the conically shaped end of the internal valve chamber100. The one-way valve permits pressurized air to enter the internal valve chamber100from the air holes46in the surface45of the mandrel40via the angled entrance passage91, but prevents escape of that pressurized air once it has passed the ball101.

As shown inFIGS. 9 and 11for example, the pressurized air circuit for actuating the expansion mechanisms that expand the diameter of the inner contacting surface58of the inner shell54of each of the stabilizers51,52desirably includes at least one outer axial conduit105(e.g.,FIGS. 4 and 9) that is formed in the outer shell53. As shown inFIG. 9for example, each outer axial conduit105is defined by a cylindrical passage that extends axially through the outer shell53and terminates at each opposite end through either the outwardly facing free edge69or the inwardly facing free edge79of the outer shell53. As schematically shown inFIG. 4for example, the pressurized air circuit further desirably includes three outer axial conduits105that extend axially into the outer shell53. Each of the three outer axial conduits105is circumferentially spaced 120 degrees from each of the other two outer axial conduits105. As schematically shown inFIG. 7Afor example, a respective one of each of the outer axial conduits105of the first stabilizer51is connected via an axially extending hollow tube75in relatively air-tight fluid communication to a respective one of the outer axial conduits105of the second stabilizer52. In this way, pressurized air entering the internal valve chamber100and the air pressure plenum94of the first stabilizer51is transported and distributed into the internal valve chamber100and the air pressure plenum94of the second stabilizer52, and vice versa.

Thus, the pressurized air circuit for actuating the expansion mechanisms that expand the diameter of the inner contacting surface58of the inner shell54of each of the stabilizers51,52includes a continuous air flow path that includes the air capture groove90of the annular piston60, the angled entrance passage91defined in the annular piston60, the internal valve chamber100defined in the annular piston60, the check valve disposed in the internal valve chamber100, the circumferentially extending air pressure plenum94defined between annular piston60and outer shell53, the three the outer axial conduits105defined in the outer shells of the stabilizers,51,52and the three axially extending hollow tube75extending between the first and second stabilizers,51,52.

The cross-sectional views shown inFIGS. 10 and 12are enlarged sections of the view inFIG. 8A, which schematically depicts the pressurized air having actuated the pressurized air circuit of the bridge sleeve30in order to increase the diameter of the inner contacting surface58of the inner shell54of the first stabilizer51at the motor end of the bridge sleeve30and the second stabilizer52at the operator end of the bridge sleeve30. In this manner, each of the plurality of slots57through the inner shell54has attained its maximum circumferential distance between the opposed sides that form these slots57such that each respective circumferential gap is uniform for the entire axial length of each of the axially extending slots57.

As shown inFIGS. 10 and 18for example, pressurized air can be supplied through the operator end of the mandrel40to the holes46in the outer surface45of the mandrel40via an axially extending central bore49from which radially extending bores149branch off as the spokes to a bicycle rim via holes150that form the entrances of each of the radial bores149. Each of the air holes46formed through the outer surface45of the mandrel40forms the exit opening of one of the radial bores149.

The arrows designated201inFIGS. 8A,8B and10schematically represent the pressurized air traveling through the axially extending central bore49of the operator end of the mandrel40. The arrows designated202inFIGS. 8A,8B and10schematically represent the pressurized air traveling from the axially extending central bore49of the operator end of the mandrel40and into the radially extending bores149via the holes150that form the entrances of each of the radial bores149of the operator end of the mandrel40. The arrow designated203inFIG. 10schematically represents the pressurized air traveling through the radially extending bores149of the operator end of the mandrel40to the holes46through the outer surface45of the mandrel40.

As schematically shown inFIG. 10by the arrow204, upon exiting the holes46through the outer surface45of the mandrel40, the pressurized air fills the air capture groove90of the annular piston60and passes into the angled entrance passage91that leads away from the air capture groove90. The pressurized air then leaves the entrance passage91and pushes past the one way valve to enter the internal valve chamber100of the annular piston60. As schematically shown inFIG. 10by the arrow205, the pressurized air leaves the internal valve chamber100via the exit opening92and passes into the air pressure plenum94defined between annular piston60and outer shell53. The pressure sealing rings64,74ensure retention of the pressurized air in the pressurized air circuit of the bridge sleeve30.

As schematically shown inFIGS. 8A and 10by the arrow designated206, the pressurized air that fills the air pressure plenum94also enters the axial air passage105formed in the outer shell53. As schematically shown inFIG. 8Aby the arrow207, the pressurized air that leaves the axial air passage105formed in the outer shell53of the motor end stabilizer51travels via the axially extending hollow tube75to the operator end stabilizer52. As schematically shown inFIGS. 8A and 12by the arrows designated208, the pressurized air that has traveled via the axially extending hollow tube75to the operator end stabilizer52enters the axial air passage105formed in the outer shell53of the operator end stabilizer52. As schematically shown inFIG. 12by the arrow209, the pressurized air leaves the axial air passage105formed in the outer shell53of the operator end stabilizer52and enters the air pressure plenum94defined between annular piston60and the outer shell53of the operator end stabilizer52. However, due to the configuration and orientation of the one-way valve disposed in the internal valve chamber100of the annular piston60of the operator end stabilizer52, pressurized air entering the internal valve chamber100via the exit opening92cannot escape via the angled entrance passage91in the annular piston60of the operator end stabilizer52and so remains in the air pressure plenum94.

As schematically shown by the arrow designated205inFIG. 10and the arrow designated210inFIG. 12, the pressurized air filling the respective air pressure plenums94pushes against the tension in the respective springs50and axially translates the respective annular pistons60toward the respective end cap81,82. Because each inner shell54is integrally connected to the its respective annular piston60, movement of the annular pistons60toward the respective annular end caps81,82results in commensurate movements of the respective inner shells54toward the respective annular end caps81,82. Such movements result in the expansion of the diameters of the inner contacting surfaces58of the inner shells54from the diameter schematically designated D4inFIG. 7Bto the diameter schematically designated D8inFIG. 8B. The diameter of the inner contacting surfaces58of the inner shells54schematically designated D4inFIG. 7Bis smaller than the diameter of the outer surface45of the mandrel40schematically designated D1inFIG. 7B. However, the diameter of the inner contacting surfaces58of the inner shells54schematically designated D8inFIG. 8Bis larger than the diameter of the outer surface45of the mandrel40schematically designated D1inFIG. 8B.

When relieved of the radially inwardly-directed compressive contact imposed by the conical surface55of the outer shell53, the circumferential gaps that define the axial slots57in the inner shell54are free to expand circumferentially to their maximum circumferential extents as schematically shown inFIGS. 3,4,8A,10and12for example. When the axial slots57in the inner shell54are free to expand circumferentially to their maximum circumferential extents as shown inFIGS. 3,4,8A,10and12for example, the diameter D8of the inner contacting surfaces58of the inner shells54becomes large enough to provide a clearance gap between the inner contacting surfaces58and the outer surface45of the mandrel40as schematically depicted inFIG. 10for example. Thus, the diameters D8of the inner contacting surfaces58of the stabilizers51,52are expanded sufficiently so as to avoid contact with the outer surface45of the mandrel40, and this contact avoidance allows the bridge sleeve30to be mounted onto and/or dismounted from the outer surface45of the mandrel40.

With the inner contacting surfaces58of the inner shells54of the stabilizers51,52expanded sufficiently to slide over the outer surface45of the mandrel40, the bridge sleeve30can be advanced onto the mandrel40sufficiently toward the registration pin44to enable the pressurized air exiting the holes46through the outer surface45of the mandrel40to expand the inner surface148of the inner core38of the bridge sleeve30sufficiently to allow the operator to slide the bridge sleeve30onto the mandrel and become properly positioned with the registration notch31engaging the registration pin44as schematically shown inFIG. 13Dfor example. Once the bridge sleeve30has attained the desired position on the mandrel40, the operator can turn off the pressurized air from the mandrel40and allow the inner surface148of the inner core38of the bridge sleeve30to contract and tightly grip the outer surface45of the mandrel40.

In order to deploy the inner contacting surfaces58of the inner shells54of the stabilizers51,52into direct contact with the outer surface45of the mandrel, it is necessary to release the pressurized air from the pressurizing air circuit of the bridge sleeve30. The release of the pressurized air within this circuit frees the flat ring springs50to apply forces that effect a sufficient reduction of the diameters of the inner contacting surfaces58that place the inner contacting surfaces58into contact with the outer surface45of the mandrel40. The diameter of the inner contacting surface58of the inner shell54becomes reduced until it matches the outer diameter D1of the outer surface45of the mandrel40. Thus, as schematically shown inFIG. 13Bfor example, the diameters D1of the inner contacting surfaces58of the stabilizers51,52become sufficiently contracted so as to come into contact with the outer surface45of the mandrel40, and this contact allows the bridge sleeve30to be maintain rigid, positive direct contact between the outer surface45of the mandrel40and the outer surface35of the bridge sleeve30. It is this rigid uninterrupted contact between the outer surface45of the mandrel40and the outer surface35of the bridge sleeve30that enables the print sleeve41to avoid the type of instability that results in the types of print deterioration described above in the background.

As schematically shown inFIGS. 1,2and13A for example, releasing the pressurized air from the pressurizing air circuit desirably can be accomplished by the operator pressing the actuating pin86projecting from the operator annular end cap82. As schematically shown inFIG. 13Afor example, this actuating pin86opens a release valve87disposed in the operator annular end cap82and in fluid communication with the pressurized air circuit via a release passage88defined in the outer shell53of the operator stabilizer52. As schematically shown inFIG. 13Afor example, the release passage88defined in the outer shell53of the operator stabilizer52is in fluid communication with the air pressure plenum94defined between annular piston60and the outer shell53of the operator stabilizer52. Moreover, the air pressure plenum94of the operator stabilizer52is in fluid communication with the air pressure plenum94of the motor stabilizer51via the three axially extending hollow tubes75extending between the first stabilizer51and the second stabilizer52.

The flat ring spring50in each stabilizer51,52provides the biasing force that keeps the inner contacting surface58of the inner shell54of each stabilizer51,52firmly in contact with the outer surface45of the mandrel40and the conical surface56of the inner shell54firmly in contact with the conical surface55of the outer shell53. The force constant that characterizes each flat ring spring50desirably should be large enough to overcome the centrifugal forces that are anticipated at the rotational speeds that can be attained by the outer surface35of the bridge sleeve30as it rotates with the mandrel40of the printing machine. Thus, the magnitude of these centrifugal forces will vary depending on the diameter of the outer surface35of the bridge sleeve30. Accordingly, the force constant of the flat ring springs50will be selected to ensure sufficient biasing force to overcome these centrifugal forces and keep the stabilizers51,52firmly in contact with the outer surface45of the mandrel40at the anticipated rotational speeds of the outer surface35of the bridge sleeve30as it rotates with the mandrel40that accommodates the line speed of the printable substrate through the printing machine.

Another consideration in the selection of the force constant of the flat ring springs50is the circumferentially directed force that occurs when the substrate that is being printed becomes involved in a so-called web wrap up event. The function of the stabilizers51,52is not to lock the bridge sleeve30onto the outer surface45of the mandrel40, as the locking function of the bridge sleeve30to the mandrel40is performed solely by the radially expandable cylindrical inner core38. However, the force constant of the flat ring springs50desirably (but not necessarily) is selected so as to be overcome during the onset of a web wrap-up event so that marring of the outer surface45of the mandrel40by the inner contacting surface58of the inner shell54of each of the stabilizers51,52might be avoided altogether or at least reduced insofar as the lengths and depths of the marring striations that otherwise might occur were the inner contacting surfaces58to remain in contact with the outer surface45of the mandrel40during a web wrap-up event.

The force constant of the flat ring springs50desirably (but not necessarily) can be selected so as to be overcome essentially instantaneously when the pressurized air is supplied to the pressurized air circuit of the bridge sleeve30via the holes46through the outer surface45of the mandrel40. Thus, it becomes possible to outfit the printing machine with sensors that detect the onset of a web wrap up event and to program the operation of the printing machine so that when such sensors detect the onset of a web wrap up event, the pressurized air is automatically supplied to the holes46in the outer surface45of the mandrel40. Then the inner contacting surfaces58of the inner shells54of the stabilizers51,52quickly become expanded in diameter and retracted from contact with the outer surface45of the mandrel40. In this way, it becomes possible to avoid (or at least reduce) marring of the outer surface45of the mandrel40by the inner contacting surfaces58of the inner shells54of each of the stabilizers51,52.

At some point it becomes necessary to remove the bridge sleeve30from the outer surface45of the mandrel40of the printing machine.FIG. 15shows an enlarged view of parts of the motor end stabilizer51mounted on the mandrel40. WhileFIG. 16shows an enlarged view of parts of the operator end stabilizer52mounted on the mandrel40. The process of removal involves first actuating the stabilizers51,52to expand the inner contacting surfaces58until their diameters D8are larger than the diameter D1of the outer surface45of the mandrel40. This is done in much the same way as the stabilizers51,52were actuated when mounting the bridge sleeve30onto the mandrel40. The supply47(FIG. 1) of pressurized air from the mandrel40is used to actuate the stabilizers51,52of the bridge sleeve30so as to expand their inner contacting surfaces58sufficiently to remove their contact with the underlying outer surface45of the mandrel40and enable the bridge sleeve30to be slid off of the mandrel40while avoiding any metal-to-metal scraping that might otherwise damage the outer surface45of the mandrel40and damage the inner contacting surfaces58of the stabilizers51,52. However, during the process of removing the bridge sleeve30from the mandrel40, the pressurized air that is expelled from the holes46in the operator end of the mandrel40is introduced into the pressurized air circuit of the bridge sleeve30via the air capture groove90of the annular piston60of the operator end stabilizer52.

As schematically shown inFIGS. 13A and 16for example, the air capture groove90of the annular piston60of the operator end stabilizer52is positioned in registry with the pressurized air delivery holes46through the outer surface45of the operator end of the mandrel40. When the operator turns on the pressurized air from the supply47(FIG. 1), the pressurized air flows successively into the air capture groove90of the annular piston60of the operator end stabilizer52, through the angled entrance passage91defined in the annular piston60of the operator end stabilizer52, through the check valve disposed in the internal valve chamber100of the annular piston60of the operator end stabilizer52, through the internal valve chamber100defined in the annular piston60of the operator end stabilizer52, into the circumferentially extending air pressure plenum94defined between annular piston60and outer shell53of the operator end stabilizer52, through the three the outer axial conduits105defined in the outer shells of the operator end stabilizer52and through the three axially extending hollow tubes75extending between the first and second stabilizers,51,52and into the circumferentially extending air pressure plenum94defined between annular piston60and outer shell53of the motor end stabilizer51.

The arrows designated201inFIGS. 14A,14B,17and18schematically represent the pressurized air traveling through the axially extending central bore49of the mandrel40. The arrows designated202inFIGS. 14A,14B and18schematically represent the pressurized air traveling from the axially extending central bore49of the operator end of the mandrel40and into the radially extending bores149via the holes150that form the entrances of each of the radial bores149of the operator end of the mandrel40. The arrow designated203inFIG. 18schematically represents the pressurized air traveling through the radially extending bores149of the operator end of the mandrel40to the holes46through the outer surface45of the mandrel40.

As schematically shown inFIG. 18by the arrow204, upon exiting the holes46through the outer surface45of the mandrel40, the pressurized air fills the air capture groove90of the annular piston60and passes into the angled entrance passage91that leads away from the air capture groove90. The pressurized air then leaves the entrance passage91and pushes past the one way valve to enter the internal valve chamber100of the annular piston60. As schematically shown inFIG. 18by the arrow205, the pressurized air leaves the internal valve chamber100via the exit opening92and passes into the air pressure plenum94defined between annular piston60and outer shell53. The pressure sealing rings64,74ensure retention of the pressurized air in the pressurized air circuit of the bridge sleeve30.

As schematically shown inFIGS. 14A and 18by the arrow designated206, the pressurized air that fills the air pressure plenum94also enters the axial air passage105formed in the outer shell53. As schematically shown inFIG. 14Aby the arrow207, the pressurized air that leaves the axial air passage105formed in the outer shell53of the operator end stabilizer52travels via the axially extending hollow tube75to the operator end stabilizer52. As schematically shown inFIGS. 14A and 17by the arrows designated208, the pressurized air that has traveled via the axially extending hollow tube75to the motor end stabilizer51enters the axial air passage105formed in the outer shell53of the motor end stabilizer51. As schematically shown inFIG. 17by the arrow209, the pressurized air leaves the axial air passage105formed in the outer shell53of the motor end stabilizer51and enters the air pressure plenum94defined between annular piston60and the outer shell53of the motor end stabilizer51. However, due to the configuration and orientation of the one-way valve disposed in the internal valve chamber100of the annular piston60of the motor end stabilizer51, pressurized air entering the internal valve chamber100via the exit opening92cannot escape via the angled entrance passage91in the annular piston60of the motor end stabilizer51and so remains in the air pressure plenum94.

As schematically shown by the arrow designated205inFIG. 18and the arrow designated210inFIG. 17, the pressurized air filling the respective air pressure plenums94pushes against the tension in the respective springs50and axially translates the respective annular pistons60toward the respective end cap81,82. Because each inner shell54is integrally connected to the its respective annular piston60, movement of the annular pistons60toward the respective annular end caps81,82results in commensurate movements of the respective inner shells54toward the respective annular end caps81,82. Such movements result in the expansion of the diameters of the inner contacting surfaces58of the inner shells54from the diameter schematically designated D1inFIG. 13Bto the diameter schematically designated D8inFIG. 14B. The diameter of the inner contacting surfaces58of the inner shells54schematically designated D1inFIG. 13Bis the same as the diameter of the outer surface45of the mandrel40schematically designated D1inFIG. 13B. However, the diameter of the inner contacting surfaces58of the inner shells54schematically designated D8inFIG. 14Bis larger than the diameter of the outer surface45of the mandrel40schematically designated D1inFIG. 14B.

The pressurized air thus can actuate the stabilizers51,52of the bridge sleeve30so as to expand their inner contacting surfaces58sufficiently to remove their contact with the underlying outer surface45of the mandrel40and enable the pressurized air to propagate further down the outer surface45of the mandrel and expand the inner surface148of the inner core38of the bridge sleeve30sufficiently to slide off of the mandrel40. As schematically shown inFIG. 18, continued supply of the pressurized air has penetrated beneath the inner surface148of the radially expandable cylindrical inner core38of the bridge sleeve30in the usual manner to provide a cushion of air that expands the diameter (schematically designated D7) of the inner surface148of the inner core38sufficiently larger than the diameter D1of the outer surface45of the mandrel40to enable the bridge sleeve30to be slid off of the outer surface45of the mandrel40.

In a bridge sleeve30such as the present invention in which some components (e.g.,54,60) are axially translated with respect to other components (e.g.,53,81,82) during each changeover cycle of mounting and dismounting the bridge sleeve30with respect to the mandrel40of the printing machine, care must be taken to guard against any misalignments that might lead to problems in mounting and dismounting the bridge sleeve30to and from the mandrel40. In accordance with one aspect of the present invention, a mechanism is provided to ensure alignment of the axially shifting components54,60with the axis of rotation30a(FIG. 2) of the bridge sleeve30and the mandrel40at each changeover cycle of the bridge sleeve30. As embodied herein and shown inFIGS. 13D,20A and20B for example, each of the annular pistons60and its respective end cap81,82is provided with a self-alignment surface60a,60bthat is disposed in opposition to each other. Each self-alignment surface60a,60bis an annular-shaped surface that extends circumferentially around the respective annular pistons60and its respective end cap81,82. Each self-alignment surface60a,60bis configured so that it is normal to the axis of rotation of the respective annular piston60and end cap81or82. The axis of rotation of each annular piston60and each end cap81,82coincides with the axis of rotation30a(FIG. 2) of the bridge sleeve30when mounted on the mandrel40of the printing machine. When the pressurized air is introduced into the internal valve chamber100(e.g.,FIG. 13D) of the annular piston60, the air pressure will move the annular piston60against the biasing force of the spring50and toward the respective end cap81or82until the self-centering surface60aof the annular piston60butts against the opposing self-centering surface60bof the respective end cap81or82. When these two self-centering surfaces60a,60btouch, because each of them is normal to the axis of rotation of the respective annular piston60and end cap81or82, alignment of the axis of rotation of the annular piston60with the axis of rotation30a(FIG. 2) of the bridge sleeve30and the mandrel40is ensured. Moreover, this self-correcting realignment of the annular piston60also effects realignment of the connected inner shell54during each cycle of pressurizing the stabilizers51,52of the bridge sleeve30.

As shown inFIGS. 3,5,6,7A,8B and14B for example, the annular piston60in each of the stabilizers51,52desirably includes a threaded hole67that extends axially into the annular piston60from the outwardly facing side65of the annular piston60but terminates before passing through the opposite inwardly facing side66of the annular piston60. As schematically shown inFIGS. 3,4and8B for example, each of the respective annular end caps81,82is provided with an axially extending through hole68that is aligned concentrically with the threaded hole67in the respective adjacent annular piston60. Desirably, as shown inFIGS. 5 and 6for example, three equally spaced apart through holes68are provided, one for each of the three equally spaced apart threaded holes67that are provided in each annular piston60. As shown inFIGS. 5 and 6for example, the three through holes68desirably are located nearer the smaller diameter edge77of the annular end caps81,82. Thus, each threaded hole67in each annular piston60is accessible by the operator from outside the bridge sleeve30without disassembling the bridge sleeve30. Each threaded hole67in each annular piston60can receive the complementarily threaded end of a tool (not shown) that the operator can screw into the threaded hole67and then manually pull the annular piston60toward the operator to loosen the piston60and its associated inner shell54in the event that they should become stuck due to the inability of the pressurized air to effect the desired expansion of the diameter of the inner contacting surface58of the inner shell of the stabilizer52for example.

In alternative embodiments of the bridge sleeve38of the present invention, it is possible to eliminate the compressible layer39disposed between the outer surface147of the inner core38and the outer shell53such as shown schematically inFIG. 18for example. Such an exemplary embodiment is schematically illustrated inFIG. 19. Each of the outer extremities on each opposite end of the inner core38is defined by a diameter D8that is larger than the diameter D1of the outer surface45of the mandrel40. The rest of the inner core38is the main portion of the inner core38extending between the two extremities and has an inner surface148that is defined by a diameter D6that is smaller than the diameter D1of the outer surface45of the mandrel40in the absence of the application of pressurized air between the outer surface45of the mandrel and the inner surface148of the inner core38. The axial length of the extremity defined by the relatively enlarged diameter D8at each opposite end of the inner core38is determined so that the holes46through the outer surface45of the mandrel40that expel pressurized air will be disposed opposite this portion of the inner surface of the inner core38having the relatively enlarged diameter D8before the leading edge140of the mandrel40reaches the main portion of the inner core38with the inner surface defined by the diameter D6. In this way, the empty space between the rigid outermost layer37and the inner core38allows the pressurized air from the holes46through the outer surface45of the mandrel40to expand the diameter of the inner surface148of the inner core38sufficiently to accommodate passage of the outer diameter D1of the mandrel40. But when the pressurized air is stopped, then the diameter of the inner surface148of the inner core38retracts to a diameter D6that is smaller than the diameter D1of the outer surface45of the mandrel40.