Patent Description:
The background of the present invention is introduced hereinafter with the discussion of techniques relating to its context. However, even when this discussion refers to documents, acts, artifacts and the like, it does not suggest or represent that the discussed techniques are part of the prior art or are common general knowledge in the field relevant to the present invention.

Bookbinding machines of different types are commonly used in bookbinding plants to produce books at industrial level. For example, a (bookbinding) perfect-binding machine has various processing stations for performing different operations on book blocks, such as feeding, pressing, milling, glue application, endpaper application, fastening lining application, (soft) covers application and delivering. For this purpose, a transport system transports the book blocks in succession through the processing stations. Typically, the transport system comprises several clamps for transporting the book blocks individually, which clamps are mounted on an endless conveyor that transports them continuously through the processing stations. The clamps require that a force should be applied to the book blocks (when closed to grasp) such as to ensure that the book blocks are held in place (especially when subjected to relatively high stresses during some of their processes, such as milling), but at the same time such as not to damage the book blocks.

Most perfect-binding machines use clamps of spring type (wherein the force to be applied to the book blocks is generated by exploiting elements being deformed elastically). However, the force applied by the (spring-type) clamps to the book blocks varies with their thickness, with the thinner the book blocks the lower the applied force. Therefore, these clamps may not hold thin book blocks in place or may damage thick book blocks; this entails the need of adjusting the springs manually in the event of substantial variations in the thickness of the book blocks. Moreover, the clamps are opened by cam mechanisms arranged at predetermined positions where necessary (i.e., in the feeding station and in the delivering station). The cam mechanisms act on a roller-based lever of each clamp in opposition to its spring. However, this causes the transport system to be subjected to relatively heavy mechanical loads and therefore requires a correspondingly robust structure. Moreover, the clamps may not be opened in positions other than the predetermined ones (for example, to remove the book blocks in case of malfunctions).

Clamps of pneumatic type (wherein the force to be applied to the book blocks is generated by exploiting pressurized gas, very often compressed air) are used as an alternative, especially in case of perfect-binding machines of small size, i.e., with <NUM>-<NUM> clamps, being used mainly in the production of books being digitally printed in medium (<NUM>-<NUM> copies), short (<NUM>-<NUM> copies) or even single book ("book-of-one") runs. The (pneumatic) clamps allow applying a constant (and adjustable) force to the book blocks, regardless of their thickness. These clamps require a distribution system of the compressed air, which comprises a rotary joint arranged at the center of the processing stations that distributes the compressed air from a (fixed) pneumofore system to the (movable) clamps. Particularly, in the case wherein the clamps move independently, corresponding ducts transfer the compressed air from the rotary joint to the clamps individually. The clamps are mechanically connected to the rotary joint, for example, via flexible connections (such as bands or chains that support the ducts as well). The clamps transported through the processing stations drag the flexible connections (and thus the ducts as well) thereby causing the rotary joint to rotate.

In operation, the clamps are closed most of the time (apart from the releasing of the book blocks being processed and the loading of the book blocks to be processed). In this condition, the rotary joint and the ducts are under pressure (for applying the required force to the clamps). This generates a relatively high friction in the rotary joint and thus requires a correspondingly strong structure of the flexible connections to drag it into rotation.

Furthermore, the clamps are equipped with corresponding discharging valves of the compressed air to allow their opening. These valves are controlled by (mechanical/magnetic) switching systems arranged in predetermined positions where necessary. However, this requires stopping the clamps with relatively high accuracy so as to ensure a correct positioning of the discharging valves with respect to the switching systems. The opening of the clamps is normally limited by adjustable stop elements according to the thickness of the book blocks. These stop elements are subjected to relatively high stresses and therefore require structures being accordingly robust. In this case as well, the clamps may not be opened in positions other than the predetermined ones wherein the switching systems are provided.

Document <CIT> discloses a bookbinding machine comprising one or more clamps.

A simplified summary of the present invention is herein presented in order to provide a basic understanding thereof; however, the sole purpose of this summary is to introduce some concepts of the invention in a simplified form as a prelude to its following more detailed description, and it is not to be interpreted as an identification of its key elements nor as a delineation of its scope.

In general terms, the present invention is based on the idea of using pressure maintaining devices.

Particularly, an aspect provides a bookbinding machine according to claim <NUM>.

A further aspect provides a distribution system according to claim <NUM>.

A further aspect provides a bookbinding plant including one or more of these bookbinding machines.

A further aspect provides a corresponding method for operating this bookbinding machine.

A further aspect provides a computer program for implementing this method.

A further aspect provides a corresponding computer program product.

More specifically, one or more aspects of the present invention are set forth in the independent claims and advantageous features thereof are set forth in the dependent claims, with the wording of all the claims that is incorporated herein verbatim by reference (with any advantageous feature provided with reference to each specific aspect that applies mutatis mutandis to every other aspect).

The solution of the present invention, as well as further features and the respective advantages, will be better understood with reference to the following detailed description, provided purely by way of a non-restrictive indication, to be read in conjunction with the accompanying drawings (wherein, for the sake of simplicity, corresponding elements are denoted with equal or similar references and their explanation is not repeated, and the name of each entity is generally used to denote both its type and its attributes, like value, content and representation). In this respect, it is expressly intended that the drawings are not necessary drawn to scale (with some details that may be exaggerated and/or simplified) and that, unless otherwise indicated, they are merely used to illustrate the structures and procedures described herein conceptually. In addition, orientations and related position references (such as upper, lower, lateral and so on) are to be understood in relation to a condition of use of the corresponding entities. Particularly:.

With reference in particular to <FIG>, an illustrative representation is shown of a bookbinding machine <NUM> wherein the solution according to an embodiment of the present invention may be applied.

Particularly, this is a (bookbinding) perfect-binding machine <NUM>; the perfect-binding machine <NUM> is used to produce books in bookbinding plants, and in particular to apply a fastening lining and/or a (soft) cover to corresponding book blocks, not shown in the figure (each formed by a block of signatures or sheets that are bound together, for example, sewn or glued, or not).

The perfect-binding machine <NUM> comprises the following components. A casing <NUM> protects internal parts of the perfect-binding machine <NUM> (not visible in the figure). The casing <NUM> has an input <NUM> for feeding book blocks to be processed, either automatically (from previous bookbinding machines that supply book blocks, such as sewing machines, not shown in the figure) or manually (by an operator of the perfect-binding machine <NUM>); furthermore, the casing <NUM> has an output <NUM> for (automatically or manually) delivering the book blocks that have been processed (for subsequent bookbinding machines that complete the production of the corresponding books, such as case-in machines or three-knife trimming machines, not shown in the figure). A plurality of processing stations are arranged within the casing <NUM> for processing the book blocks. A control unit <NUM> (for example, an industrial PC) controls operation of the perfect-binding machine <NUM>. Particularly, the control unit <NUM> has (not visible in the figure) one or more microprocessors (which provide the logic capability of the control unit <NUM>), a non-volatile memory (such as a ROM) that stores basic code for a bootstrap of the control unit <NUM>, a volatile memory (such as a RAM) used as working memory by the microprocessor, a mass memory (such as an SSD) for storing programs and data, and controllers for peripheral units (such as an input device, an output device, a drive for reading/writing removable storage devices such as USB keys and so on). In this specific implementation, the peripheral units comprise a touch-screen <NUM> both for displaying information and for entering commands/data.

With reference now to <FIG>, a partially cut-away schematic representation in perspective view is shown of the bookbinding machine <NUM> wherein the solution according to an embodiment of the present invention may be applied.

Particularly, the figure shows the perfect-binding machine <NUM> with its processing stations sketched in broken lines and identified with the references 205a, 205b, 205c, 205e and 205e. At least part of the processing stations 205a-205e process the book blocks while they are stationary therein; for example, such (stationary) processing stations 205a-205e comprise a feeding station (which is used to feed the book blocks to be processed), a cover application station (which applies covers to the book blocks), and a delivering station (which delivers the book blocks that have been processed). Possible processing stations 205a-205e instead process the book blocks as they move through them; for example, such (motion) processing stations 205a-205e comprise a milling station (which mills the book blocks), a gluing station (which applies glue to the book blocks) and a fastening station (which applies fastening linings to the book blocks). A plurality of clamps of fluid dynamic control type, and in particular of pneumatic type, three in the example at issue denoted with the references 210a, 210b and 210c, are used to transport corresponding book blocks individually (not shown in the figure) in the perfect-binding machine <NUM>. For example, each clamp <NUM>10a-210c comprises a (bigger) internal plate 215a-215c and a (smaller) external plate 220a-220c facing each other horizontally (for transporting the book blocks arranged vertically). The (external) plate 220a-220c is movable horizontally relative to the (internal) plate 215a-215c between an opened condition of the clamp 210a-210c (wherein the plate 220a-220c is moved away from the plate 215a-215c) and a closed condition of the clamp 210a-210c (wherein the plate 220a-220c is moved close to the plate 215a-215c).

A transport system <NUM> (only partially visible in the figure) transports the clamps 210a-210c, and therefore the corresponding book blocks as well, through the processing stations 205a-205e on an endless guide (oval-shaped, partially visible in the figure) that crosses them. A (support) plate <NUM> coupled with the guide of the transport system <NUM> covers the same (above it). For example, the transport system <NUM> is implemented as described in the international application published with No. <CIT>. Briefly, an endless chain (not visible in the figure) selectively drives the clamps 210a-210c via corresponding pegs. Particularly, the (endless) chain comprises active sections along the guide and passive sections inside the guide at some of the (stationary) processing stations 205a-205e; in the active sections each peg engages the corresponding clamp 210a-210c thereby transporting it therewith, whereas in the passive sections each peg disengages from the corresponding clamp 210a-210c thereby leaving it stationary (in the corresponding processing station 205e-205e). Alternatively, the transport system <NUM> is implemented as described in the <CIT>. In this case, several endless chains with corresponding pegs are arranged in continuous succession along the guide. The (endless) chains are at least partly driven at different speeds. Exchanging areas are defined between each pair of adjacent chains at some of the (stationary) processing stations 205a-205e, wherein each clamp 210a-210c is exchanged between the adjacent chains. Each chain is divided by the corresponding pair of exchanging areas into an active section (along the guide) and a passive section (inside the guide); in the active sections the corresponding peg engages the clamps 210a-210c in succession thereby transporting them therewith, while in the passive sections the corresponding peg does not act on the clamps 210a-210c.

A fluid dynamic system <NUM> supplies fluid under pressure; for example, this is a pneumofore system, such as a compressor, <NUM> that raises the pressure of a gas, such as air, from atmospheric pressure (about <NUM> hPa) to an operating pressure (for example, <NUM>-<NUM> hPa, such as <NUM> hPa ). A distribution system <NUM> distributes the compressed air to the clamps 210a-210c. The distribution system <NUM> comprises the following components. A rotary joint <NUM> is arranged above the plate <NUM>, at the center thereof, for distributing the compressed air from the (fixed) compressor <NUM> to the (movable) clamps 210a-210c. (Closing) supply ducts 250a, 250b and 250c supply the compressed air for the clamps 210a, 210b and 210c, respectively, from the compressor <NUM> to the rotary joint <NUM> for acting on the clamps 210a, 210b and 210c, respectively, for closing. Corresponding (closing) transfer ducts 255a, 255b and 255c transfer the compressed air from the rotary joint <NUM> to the clamps 210a, 210b and 210c, respectively.

In the solution according to an embodiment of the present invention, as described in detail in the following, corresponding maintaining devices, for example, non-return valves (not shown in the figure) are arranged along the transfer ducts 255a-255c. The non-return valves maintain corresponding portions of the transfer ducts 255a-255c downstream thereof (along transfer directions of the compressed air) under pressure. In this way, once the compressed air has been supplied to each clamp 210a-210c (from the compressor <NUM> via its supply duct 250a-250c, the rotary joint <NUM> and its transfer duct 255a-255c) so to close it, the supply of the compressed air may be interrupted; the clamp 210a-210c remains closed in any case thanks to the non-return valve that maintains the downstream portion of the transfer duct 255a-255c under pressure.

In this way, for most of the time that each clamp 210a-210c is closed (apart from a short initial time interval for bringing its transfer duct 255a-255c under pressure) the corresponding portion of the rotary joint <NUM> is not under pressure. As a consequence, the rotary joint <NUM> is subjected to significantly less friction (than when it supplies compressed air to the transfer duct 255a-255c) and thus significantly less force is required to drag it into rotation. This makes it possible to reduce the risk of breakages caused by the force transmitted to the rotary joint <NUM> (with a beneficial effect on the reliability of the bookbinding machine <NUM>) and/or to use lighter structures (with a beneficial effect on costs).

Furthermore, in this way the clamps remain closed even in stop conditions of the perfect-binding machine (such as due to a malfunction or an emergency situation), outage of electric power supply, loss of pressure and so on. Therefore, the book blocks do not fall (thereby avoiding corresponding risks of damage).

In a specific implementation, for each clamp 210a, 210b and 210c there is also provided an (opening) supply duct 260a, 260b and 260c, respectively, and an (opening) transfer duct 265a, 265b and 265c, respectively, which provide the compressed air from the compressor <NUM> to the rotary joint <NUM> and from the rotary joint <NUM> to the clamp 210a, 210b and 210c, respectively, for acting thereon for (slow) opening. Chains 270a, 270b and 270c extend from the rotary joint <NUM> to the clamps 210a, 210b and 210c, respectively. Each chain 270a-270c supports the corresponding (closing/opening) transfer ducts 255a-255c, 265a-265c. The chains 270a-270c and the transfer ducts 255a-255c,265a-265c have an (outer) end integral with the corresponding clamps 210a-210c and another (inner) end coupled with the rotary joint <NUM> so as to allow it to rotate around a (vertical) longitudinal axis thereof. In this way, each clamp 210a-210c drags the chain 270a-270c with the corresponding transfer ducts 255a-255c,265a-265c during at least part of its movement along the guide of the transport system <NUM>, thereby causing them to rotate around the rotary joint <NUM> (with the chain 270a-270c and the transfer ducts 255a-255c,265a-265c that bend horizontally as the distance of the clamp 210a-210c from the rotary joint <NUM> varies). The lower friction to which the rotary joint <NUM> is subjected thanks to the above requires the application of a lower force by the chains 270a-270c (thereby allowing their use instead of other stronger mechanical structures of flexible type). Furthermore, the chains 270a-270c rest on the plate <NUM> (thereby further improving their operation). All of the above allows obtaining a particularly compact, simple and functional structure.

With reference now to <FIG>, a schematic representation in perspective view is shown of the rotary joint <NUM> that may be used to implement the solution according to an embodiment of the present invention.

The rotary joint <NUM> comprises the following components. A stator defining the stationary part of the rotary joint <NUM> is formed by a shaft <NUM> that extends vertically. The shaft <NUM> is provided, on an upper base 305u thereof, with corresponding (closing) supply ports 310a, 310b and 310c and (opening) supply ports 315a, 315b and 315c to which the closing supply ducts and the opening supply ducts, respectively, are connected, through fittings, for receiving the compressed air from the compressor (not shown in the figure).

Rotors defining the movable part of the rotary joint <NUM> are formed by cylinders 320a, 320b and 320c corresponding to the clamps (not shown in the figure). The cylinders 320a-320c are mounted (in rotating-type coupling) around the shaft <NUM> at different positions along it (one on top of the other vertically). Each cylinder 320a-320c is provided with corresponding (closing) transfer ports 325a, 325b and 325c and (opening) transfer ports 330a, 330b and 330c to which the closing transfer ducts and the opening transfer ducts, respectively, are connected, through fittings, for providing the compressed air to the corresponding clamps (not shown in the figure); as described below, the transfer ports 325a-325c,330a-330c allow an air-tight flow of the compressed air from the corresponding supply ports 310a-310c,315a-315c during the rotation of the cylinder 320a-320c.

With reference not to <FIG>, a schematic representation in plant view and in cross-section view is shown of the rotary joint <NUM> that may be used to implement the solution according to an embodiment of the present invention.

Particularly, the figure shows the rotary joint in cross-section along a plane A-A passing through the supply ports 310a,315a (therefore, the following description will relate more specifically to the corresponding components of the rotary joint <NUM>, with similar considerations that apply to the components corresponding to the supply ports 310b,315b and the supply ports 310c,315c).

The cylinders 320a-320c are stacked and coupled to each other via thrust bearings 405ab (between the cylinders 320a and 320b) and 405bc (between the cylinders 320b and 320c). The cylinders 320a-320c are fitted onto the shaft <NUM> and coupled therewith through radial bearings 410a (between the bottom of the cylinder 320a and the shaft <NUM>) and 410c (between the top of the cylinder 320c and the shaft <NUM>). Each cylinder 320a, 320b and 320c has a (closing) groove 415a, 415b and 415c, respectively, and an (opening) groove 420a, 420b and 420c, respectively. The grooves 415a-415c,420a-420c extend from an inner surface of the cylinder 320a-320c (facing the shaft <NUM>); the grooves 415a-415c, 420a-420c have a circumferential pattern, and extend perpendicularly to a longitudinal axis of the cylinder 320a-320c at different heights along it. In each cylinder 320a-320c, the transfer port 325a-325c and the transfer port 330a-330c are connected to the groove 415a-415c and to the groove 420a-420c, respectively, through the cylinder 320a-320c (connections being not visible in the figure). Three toroidal gaskets (O-rings) are arranged between each cylinder 320a-320c and the shaft <NUM>. Particularly, a gasket 425a, 425b, 425c and a gasket 430a, 430b, 430c are arranged around the groove 415a-415c (along the cylinder 320a-320c) for ensuring the sealing of a corresponding (closing) chamber formed between the cylinder 320a-320c and the shaft <NUM>, and the same gasket 430a,430b,430c and a gasket 435a,435b,435c are arranged around the groove 420a-420c (along the cylinder 320a-320c) for ensuring the sealing of a corresponding (opening) chamber formed between the cylinder 320a-320c and the shaft <NUM>.

A (closing) supply duct 440a, 440b and 440c, only the first one visible in the figure, extends along the shaft <NUM> from the supply port 310a, 310b and 310c, respectively; likewise, an (opening) supply duct 445a, 445b and 445c, only the first one visible in the figure, extends along the shaft <NUM> from the supply port 315a, 315b and 315c, respectively. The supply ducts 440a-440c,445a-445c have different lengths, so that they extend from the (upper) base 305u of the shaft <NUM> to different depths, which match the positions of the corresponding grooves 415a-415c,420a-420c (the supply duct 440a for the groove 415a and the supply duct 445a for the groove 420a being visible in the figure). The supply duct 440a, 440b and 440c then extends transversely to the shaft <NUM> until it ends with a (closing) mouth 450a, 450b and 450c, respectively (only the first one visible in the figure); likewise, the supply duct 445a, 445b and 445c then extends transversely to the shaft <NUM> until it ends with an (opening) mouth 455a, 455b and 455c, respectively (only the first one visible in the figure). The mouth 450a-450c and the mouth 455a-455c are open on a side surface of the shaft <NUM> opposite the groove 415a-415c and the groove 420a-420c, respectively (the mouth 450a for the groove 415a and the mouth 455a for the groove 420a being visible in the figure). In this way, each transfer port 325a-325c,330a-330c is always (air-tight) connected to the mouth 450a-450c,455a-455c of the corresponding supply duct 440a-440c,445a-445c, through the corresponding groove 415a-415c,420a-420c, in any position during the rotation of the corresponding cylinder 320a-320c around the shaft (the transfer port 325a connected to the mouth 450a of the supply duct 440a through the groove 415a and the transfer port 330a connected to the mouth 450a of the supply duct 445a through the groove 420a being visible in the figure).

With reference now to <FIG>, a functional diagram is shown of the distribution system <NUM> according to an embodiment of the present invention.

The distribution system <NUM> controls actuators 505a, 505b and 505c, for example, pneumatic cylinders, which act on the clamps 210a, 210b and 210c, respectively; particularly, for each clamp 210a-210c there are provided two pneumatic cylinders 505a-505c, which move its plate 220a-220c with respect to its plate 215a-215c. The pneumatic cylinders 505a-505c are arranged symmetrically with respect to the plate 220a-220c, for example, symmetrically with respect to a (vertical) longitudinal axis thereof and at the center in height. This allows acting in a more balanced way on the plate 220a-220c and therefore reducing its mechanical stresses. The pneumatic cylinders 505a-505c are of double-acting type. Particularly, each pneumatic cylinder 505a, 505b and 505c comprises a barrel 510a, 510b and 510c, respectively, and a piston 515a, 515b and 515c, respectively. The piston 515a-515c slides within the barrel 510a-510c, moving between a (closing) condition wherein the pneumatic cylinder 505a-505c is shortened with the piston 515a-515c retracted in the barrel 510a-510c and an (opening) condition wherein the pneumatic cylinder 505a-505c is lengthened with the piston 515a-515c extracted from the barrel 510a-510c. A base of each piston 515a, 515b and 515c within the barrel 510a, 510b and 510c, respectively, splits it into a (closing) chamber 520a, 520b and 520c, respectively, and an (opening) chamber 525a, 525b and 525c, respectively. When the compressed air is supplied to the chamber 520a-520c it acts on a (closing) surface of the piston 515a-515c, thereby applying a (closing) force thereto that retracts it into the barrel 510a-510c for pulling the plate 220a-220c towards the plate 215a-215c thereby closing the clamp 210a-210c; conversely, when the compressed air is supplied to the chamber 525a-525c it acts on an (opening) surface of the piston 515a-515c, thereby applying an (opening) force thereto that extracts it from the barrel 510a-510c for pushing the plate 220a-220c away from the plate 215a-215c thereby opening the clamp 210a-210c. The opening surface (equal to the entire base of the piston 515a-515c) is slightly greater than the closing surface (equal to the base of the piston 515a-515c minus its part covered by a stem thereof that protrudes from the barrel 510a-510c), for example, with the opening surface equal to <NUM>-<NUM> times, preferably <NUM>-<NUM> times, and even more preferably <NUM>-<NUM> times, such as <NUM> times the closing surface.

(Closing) pneumatic lines 535a, 535b and 535c supply the compressed air from the compressor <NUM> to the chambers 520a, 520b and 520c of the pneumatic cylinders 505a, 505b and 505c, respectively, while (opening) pneumatic lines 540a, 540b and 540c supply the compressed air from the compressor <NUM> to the chambers 525a, 525b and 525c of the pneumatic cylinders 505a, 505b and 505c, respectively. Each pneumatic line 535a-535c is formed by the supply duct 250a-250c, by the corresponding portion of the rotary joint <NUM> and by the transfer duct 255a-255c (which as a consequence splits by means of a corresponding tee near the chambers 520a-520c of the two pneumatic cylinders 505a-505c); likewise, each pneumatic line 540a-540c is formed by the supply duct 260a-260c, by the corresponding portion of the rotary joint <NUM> and by the transfer duct 265a-265c (which as a consequence splits by means of a corresponding tee near the chambers 525a-525c of the two pneumatic cylinders 505a-505c). The non-return valves, denoted with the references 545a, 545b and 545c, arranged along the transfer ducts 255a, 255b and 255c, respectively, define downstream portions of the transfer ducts 255a, 255b and 255c and remaining upstream portions of the pneumatic lines 535a-535c (along transfer directions of the compressed air from the compressor <NUM> to the chambers 520a-520c). The non-return valves 545a-545c are arranged close to the chambers 520a-520c, so as to limit possible pressure losses in the downstream portions of the transfer ducts 255a-255c when the upstream portions of the pneumatic lines 535a-535c are not under pressure. Discharging ducts 550a, 550b and 550c extend from the transfer ducts 255a, 255b and 255c, respectively, downstream of the non-return valves 545a, 545b and 545c, respectively (via corresponding tees). The discharging ducts 550a, 550b and 550c end with discharging valves 555a, 555b and 555c, respectively. The discharging valves 555a, 555b and 555c are normally closed, and are controlled for opening by discharging buttons 560a, 560b and 560c, respectively. Control ducts 565a, 565b and 565c extend from the transfer ducts 265a, 265b and 265c, respectively (via corresponding tees). The control ducts 565a, 565b and 565c are connected to corresponding opening controls of pneumatic-type of the non-return valves 545a, 545b and 545c, respectively.

Referring now to <FIG>, an activity diagram is shown describing the flow of activities relating to an implementation of the solution according to an embodiment of the present invention. Particular, the diagram represents an exemplary process that may be used to control the perfect-binding machine with a method <NUM>. In this respect, each block may correspond to one or more executable instructions for implementing the specified logic function on the control unit of the perfect-binding machine by a corresponding control program (stored in the mass memory, for example, initially installed therein from removable storage units or from a network, and loaded, at least in part, into the working memory when the control program is running).

The control program controls the transport system for transporting the clamps through the processing stations of the perfect-binding machine continuously for each processing cycle of the book blocks, for example, as disclosed in the international application published with the No. <CIT> and in the <CIT> of above. Briefly, the control program stops the transport system (for a stop time) whenever a clamp reaches the cover application station. The clamp in the cover application station remains stationary therein (engaged by the transport system) for the same stop time. Other clamps in the other stationary processing stations are instead disengaged from the transport system, so that they remain stationary therein for times longer than the stop time (depending on the lengths of the corresponding passive sections of the transport system).

The control process of the perfect-binding machine is described below with joint reference to <FIG>, which show an example of control of a clamp of the bookbinding machine according to an embodiment of the present invention. For simplicity, reference will be made in the figures to a generic clamp whose references are denoted without the suffixes a-c.

With reference initially to <FIG> and <FIG>, a starting condition is now considered wherein the transport system is stopped, with a clamp <NUM> stationary in the feeding station (disengaged from the transport system). The clamp <NUM> is (partially) opened, with the corresponding pneumatic line <NUM> and pneumatic line <NUM> discharged to the atmospheric pressure. The feeding station is provided with a stop element <NUM>, which is controlled by an actuator <NUM> (for example, a stepper motor). The actuator <NUM> positions the stop element <NUM> according to a format of a (new) book block to be loaded into the clamp <NUM> (not shown in the figure); particularly, the stop element <NUM> limits the opening of the clamp <NUM> so that the plate <NUM> is at a distance from the plate <NUM> slightly higher than a thickness of the book block (for example, <NUM>-<NUM>). The control program is in a waiting cycle at block <NUM> for the loading of the book block.

With reference now to <FIG> and <FIG>, as soon as the operator loads the book block into the clamp <NUM> (for example, detected automatically or through a corresponding command entered by the operator), the control program closes the clamp. For this purpose, the control program at block <NUM> controls the compressor <NUM> to supply the compressed air at the operating pressure to the closing pneumatic line <NUM>. The compressed air is introduced into the closing chambers <NUM> of the corresponding pneumatic cylinders <NUM> (via the closing supply duct <NUM>, the rotary joint <NUM> and the closing transfer duct <NUM> of the closing pneumatic line <NUM>). The compressed air in the closing chambers <NUM> acts on the closing surfaces of the pistons <NUM>, thereby applying the closing force thereto (for example, <NUM>-<NUM> kN with respect to the opening force applied by the opening chambers <NUM> at the atmospheric pressure). The closing force then retracts the pistons <NUM> into the barrels <NUM> thereby (partially) closing the clamp <NUM>; particularly, the pistons <NUM> move the plate <NUM> towards the plate <NUM>, until it stops (squeezing it) against the book block, denoted with the reference <NUM> (thereby gripping it). The movement of the plate <NUM> takes place starting from the clamp <NUM> that is only partially opened in a slightly greater way than the thickness of the book block <NUM> (as described above); therefore, the closing of the clamp <NUM> (for gripping the book block <NUM>) requires a limited stroke of the plate <NUM> and is therefore relatively fast, with a positive effect on the yield of the perfect-binding machine. This condition is maintained for a (pressurization) time sufficient to bring the closure chambers <NUM> under pressure (for example, <NUM>-<NUM>, preferably <NUM>-<NUM> and still more preferably <NUM>-<NUM>, such as <NUM>), after which the control program at block <NUM> controls the compressor <NUM> to stop supplying the compressed air to the closing pneumatic line <NUM>. Nevertheless, the non-return valve <NUM> maintains the downstream portion of the closing transfer duct <NUM> under pressure, so that the clamp <NUM> remains closed.

The control program at block <NUM> restarts the transport system (once processing of the book block of another clamp in the cover application station is completed). As soon as the transport system engages the clamp again, it transports the latter through the subsequent processing stations that carry out the corresponding processing on the book block (with the transport system stopped whenever the clamp reaches a stationary processing station, disengaging from it with the exception of when in the cover application station).

With reference now to <FIG> and <FIG> , when the clamp reaches the delivering station, the control program opens the clamp quickly. For this purpose, the control program at block <NUM> controls the compressor <NUM> to supply the compressed air at the operating pressure to the opening pneumatic line <NUM>. The compressed air is introduced into the opening chambers <NUM> of the corresponding pneumatic cylinders <NUM> (via the opening supply duct <NUM>, the rotary joint <NUM> and the opening transfer duct <NUM> of the opening pneumatic line <NUM>). The compressed air in the opening chambers <NUM> acts on the opening surfaces of the pistons <NUM>, thereby applying the opening force thereto. At the same time, the compressed air is introduced into the control line <NUM> of the opening pneumatic line <NUM>. The compressed air in the control line <NUM> opens the non-return valve <NUM>, thereby discharging the downstream portion of the closing transfer duct <NUM>, and then the closing chambers (not visible in the figure) as well, quickly to the atmospheric pressure. As a consequence, the opening force (for example, <NUM>-<NUM> kN relative to the closing force applied by the closing chambers at the atmospheric pressure) extracts the pistons <NUM> from the barrels <NUM> thereby (fully) opening the clamp <NUM>; particularly, the pistons <NUM> move the plate <NUM> away from the plate <NUM>, until they reach an opening end-of-stroke in the barrels <NUM>, thereby releasing the (processed) book block, not shown in the figure, in a relatively quick way. This has a positive effect on the yield of the bookbinding machine, without any risk of kickback since it occurs while the clamp <NUM> is stationary. Furthermore, the opening of the clamp <NUM> does not require any (precise) alignment with other external elements.

With reference now to <FIG> and <FIG>, after an interval of time sufficient to ensure that the book block has been released (for example, <NUM>-<NUM>), the control program closes the clamp <NUM> again in a similar way as above. Particularly, the control program at block <NUM> controls the compressor <NUM> to supply the compressed air at the operating pressure to the closing pneumatic line <NUM>. The compressed air is introduced into the closing chambers <NUM> of the corresponding pneumatic cylinders <NUM>, and it acts on the closing surfaces of the pistons <NUM> thereby applying the closing force thereto. The closing force then retracts the pistons <NUM> into the barrels <NUM> thereby (fully) closing the clamp <NUM>; particularly, the pistons <NUM> move the plate <NUM> towards the plate <NUM>, until they reach a closing end-of-stroke in the barrels <NUM>. This condition is maintained for the pressurization time, after which the control program at block <NUM> controls the compressor <NUM> to interrupt supplying the compressed air to the closing pneumatic line <NUM> (with the non-return valve <NUM> that maintains the downstream portion of the closing transfer duct <NUM> under pressure). In this case, wherein the travel from the delivering station to the feeding station (where the supply of the compressed air to the closing pneumatic line <NUM> is in any case re-established, as described below) is very short and therefore the clamp <NUM> may cause no rotation of the rotary joint <NUM> (but only a bend of the corresponding chain, not shown in the figure), in an alternative implementation (not shown in the figure) it is also possible to maintain the supply of the compressed air to the closing pneumatic line <NUM>.

The control program at block <NUM> restarts the transport system (once processing of the book block of another clamp in the cover application station has been completed). As soon as the transport system engages the clamp again, it transports the latter towards the feeding station (with the closed clamp that avoids the risk of impacts with other parts of the bookbinding machine during this movement).

With reference again to <FIG> and <FIG>, when the clamp reaches the feeding station, the control program opens the clamp slowly. For this purpose, the control program to block <NUM> controls the compressor <NUM> to supply the compressed air at the same operating pressure to both the opening pneumatic line <NUM> and the closing pneumatic line <NUM>. The compressed air is introduced into the opening chambers <NUM> and into the closing chambers <NUM> of the corresponding pneumatic cylinders <NUM> (via the opening/closing supply lines <NUM>,<NUM>, the rotary joint <NUM> and the opening/closing transfer lines <NUM>,<NUM> of the opening/closing pneumatic lines <NUM>,<NUM>). The compressed air in the opening chambers <NUM> acts on the opening surfaces of the pistons <NUM>, thereby applying the opening force thereto, and the compressed air in the closing chambers <NUM> acts on the closing surfaces of the pistons <NUM>, thereby applying the closing force thereto. Since the opening surface is slightly greater than the closing surface, the opening force is accordingly slightly higher than the closing force (being given by the same operating pressure multiplied by the corresponding opening/closing surfaces). As a consequence, the difference between the opening force and the closing force (for example, <NUM>-<NUM> kN, preferably <NUM>-<NUM> kN, and still more preferably <NUM>-<NUM> kN , such as <NUM> kN) extracts the pistons <NUM> from the barrels <NUM> slowly thereby (partially) opening the clamp <NUM> in a relatively slow way; particularly, the pistons <NUM> move the plate <NUM> away from the plate <NUM>, until it stops against the stop element <NUM>, previously positioned according to the format of the (new) book block to be loaded (not shown in the figure) by the actuator <NUM>. The slow opening of the clamp <NUM> substantially reduces the stresses of the plate <NUM> against the stop element <NUM>. Furthermore, this makes it safer for the operator to use the feeding station, since the reduced opening speed and force applied to the plate <NUM> avoid (or at least substantially reduce) the risk of injury in the event of accidental contact with the plate <NUM> while it is moving. After an interval of time sufficient to ensure that the clamp <NUM> has opened (for example, <NUM>-<NUM>), the control program at block <NUM> controls the compressor <NUM> to stop supplying the compressed air to the closing pneumatic line <NUM>. In this condition, the compressed air in the control line <NUM> of the opening pneumatic line <NUM> (under pressure) opens the non-return valve <NUM>, thereby discharging the downstream portion of the closing transfer line <NUM>, and therefore the closure chambers <NUM> as well, quickly to the atmospheric pressure. After an interval of time sufficient to ensure that the downstream portion of the closing transfer duct <NUM> has discharged (for example, <NUM>-<NUM>), the control program at block <NUM> controls the compressor <NUM> to stop supplying the compressed air to the opening pneumatic line <NUM> as well. As a consequence, the opening pneumatic line <NUM>, and therefore the opening chambers <NUM> as well, discharge to the atmospheric pressure. The process returns to block <NUM> (with the clamp again in the initial condition of above) to repeat the same operations continuously.

With reference now to <FIG> and <FIG>, in a completely independent way the process passes from block <NUM> to block <NUM> when the control program detects a stop condition of the perfect-binding machine. The stop condition may be caused by a malfunction of the perfect-binding machine, signaled automatically by corresponding sensors (for example, in the event of a jam) or manually by the operator (for example, by pressing a stop button), or by an emergency situation (for example, signaled manually by the operator using the touch-screen). In response thereto, the control program stops the operation of the perfect-binding machine (completely interrupting its electrical power supply and thus the operation of the compressor <NUM>). Nevertheless, the clamps <NUM> remain closed (thanks to the downstream portions of the corresponding closing transfer ducts <NUM> that are maintained under pressure by their non-return valves <NUM>). In this way, the book blocks <NUM> gripped by these clamps <NUM> do not fall even if the bookbinding machine is blocked. The control program waits at block <NUM> for the stop condition to be solved. For this purpose, the operator intervenes on the perfect-binding machine accordingly. Particularly, should this require the removal of a book block <NUM> (or more) held by a corresponding clamp <NUM>, the operator presses its discharging button <NUM>. As a consequence, the discharging button <NUM> opens the corresponding discharging valve <NUM>, thereby quickly discharging the downstream portion of the closing transfer duct <NUM>, and therefore the closing chambers <NUM> as well, to the atmospheric pressure. As a consequence, no force is applied to the pistons <NUM> (from the closing/opening chambers <NUM>,<NUM> both at the atmospheric pressure), thereby freeing the clamp <NUM> (which however remains closed holding the book block <NUM>). The operator may now grip the book block <NUM> and then remove it from the clamp <NUM>, with the (free) clamp <NUM> that opens slightly as a consequence. This operation may be performed in a very practical way by acting directly on the clamp <NUM>, at any position thereof along the transport system. In any case, once the stop condition has been solved, the operator enters a restart command on the touch-screen. In response thereto, the control program at block <NUM> restarts the bookbinding machine (resuming the operations of blocks <NUM>-<NUM> from the point wherein they have been interrupted). The process then returns to block <NUM> waiting for a subsequent stop condition.

With reference now to <FIG>, a schematic representation in perspective view is shown of the rotary joint according to a different embodiment of the present invention.

The rotary joint differs from the one described above for the following reasons (for simplicity, the different elements are identified with similar references starting with the number <NUM>). The fixed part of the rotary joint <NUM> is formed by a shaft <NUM> with the (closing/opening) supply ports 310a-310c,315a-315c that are now distributed in part on an upper base thereof 805u and in part on a lower base thereof 805d (opposite each other). For example, in the figure the supply port 310b, the supply port 310c and the supply port 315c are provided on the upper base 805u, whereas the supply port 310a, the supply port 315a and the supply port 315b are provided on the lower base 805d. Corresponding (closing/opening) supply ducts 840a-840c,845a-845c then extend from the (closing/opening) supply ports 310a-310c,315a-315c in part from the upper base 805u and in part from the lower base 805d. The supply ducts 840a-840c,845a-845c have lengths such that they still extend to different depths along the shaft <NUM> where the corresponding transfer ports 325a-325c,330a-330c are provided (the supply duct 840a for the transfer port 325a, the supply duct 845a for the transfer port 330a, the supply duct 840b for the transfer port 325b, the supply duct 845b for the transfer port 330b, the supply duct 840c for the transfer port 325c and the supply duct 845c for the transfer port 330c).

As a result, the shaft <NUM> may be made with a smaller diameter. This accordingly reduces the friction to which the rotary joint <NUM> is subjected and thus the force required to drag it into rotation. In this way, it is possible to further reduce the risk of breakage caused by the force transmitted to the rotary joint <NUM> and/or to use even lighter structures.

In order to satisfy local and specific requirements, a person skilled in the art may apply many logical and/or physical modifications and alterations to the present invention, provided that it remains within the scope of the claims. More specifically, although this invention has been described with a certain degree of particularity with reference to one or more embodiments thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible. Particularly, different embodiments of the present invention may be practiced even without the specific details (such as the numerical values) set forth in the preceding description to provide a more thorough understanding thereof; conversely, well-known features may have been omitted or simplified in order not to obscure the description with unnecessary particulars. Moreover, it is expressly intended that specific elements and/or method steps described in connection with any embodiment of the present disclosure may be incorporated in any other embodiment as a matter of general design choice. Moreover, items presented in a same group and different embodiments, examples or alternatives are not to be construed as de facto equivalent to each other (but they are separate and autonomous entities). In any case, each numerical value should be read as modified according to applicable tolerances; particularly, unless otherwise indicated, the terms "substantially", "about", "approximately" and the like should be understood as within <NUM>%, preferably <NUM>% and still more preferably <NUM>%. Moreover, each range of numerical values should be intended as expressly specifying any possible number along the continuum within the range (comprising its end points). Ordinal or other qualifiers are merely used as labels to distinguish elements with the same name but do not by themselves connote any priority, precedence or order. The terms include, comprise, have, contain, involve and the like should be intended with an open, non-exhaustive meaning (i.e., not limited to the recited items), the terms based on, dependent on, according to, function of and the like should be intended as a non-exclusive relationship (i.e., with possible further variables involved), the term a/an should be intended as one or more items (unless expressly indicated otherwise), and the term means for (or any means-plus-function formulation) should be intended as any structure adapted or configured for carrying out the relevant function.

For example, an embodiment provides a bookbinding machine. However, the bookbinding machine may be of any type (for example, a perfect-binding machine, a back-gluing machine, a case-in machine and so on).

In an embodiment, the bookbinding machine comprises one or more clamps of fluid dynamic type for transporting book blocks. However, the clamps may be in any number and of any type (for example, pneumatic/hydraulic, with a fixed plate and a movable plate, two movable plates, a pliers-like structure and so on), and they may be used to transport any book blocks (for example, formed by signatures, flat sheets, with or without inserts, sewn, glued, stapled or otherwise bound, and so on).

In an embodiment, the bookbinding machine comprises a fluid dynamic system for supplying a pressurized fluid. However, the fluid dynamic system may be of any type (for example, a pneumofore system, such as a positive-displacement/dynamic compressor, a pump and the like, a hydraulic system, such as a piston pump, a gear pump, and so on) for providing any fluid (for example, a gas, such as air, ionized air, nitrogen and the like, a liquid, such as oil, water, and so on) and at any pressure value.

In an embodiment, the bookbinding machine comprises corresponding closing transfer ducts. However, the closing transfer ducts may be of any type, shape and size (for example, flexible tubes, rigid tubes and so on) and configured in any way (for example, a duct extending from the rotary joint to each clamp, a duct extending from the rotary joint to a duct integral with the transport system from which a duct extends to each clamp, and so on).

In an embodiment, the closing transfer ducts are for transferring the pressurized fluid to the clamps thereby acting thereon for closing. However, the fluid under pressure may act on each clamp for closing in any way (for example, through actuators in any number and of any type, which apply a pulling/pushing force of any value and so on).

In an embodiment, the bookbinding machine comprises a rotary joint for distributing the pressurized fluid from the fluid dynamic system to each of the closing transfer ducts. However, the rotary joint may be of any type (for example, with supply to its fixed shaft only from a top/bottom end, from both ends, at the bases and/or the side surface, dragged into rotation by the clamps or driven independently in continuous or step-by-step way, such as via a motor, pistons and so on).

In an embodiment, the bookbinding machine comprises a transport system for transporting the clamps around the rotary joint. However, the transport system may be of any type (for example, based on one or more conveyors such as chains, belts and the like, with or without passive sections, and so on).

In an embodiment, the bookbinding machine comprises corresponding maintaining devices arranged along the closing transfer ducts for maintaining the fluid under pressure in corresponding downstream portions of the closing transfer ducts (each being downstream of the corresponding maintaining device along a transfer direction of the pressurized fluid from the rotary joint to the corresponding clamp). However, the maintaining devices may be of any type (for example, passive such as non-return valves, active such as shut-off valves and so on) and they may be arranged at any position along the closing transfer ducts.

In an embodiment, the bookbinding machine comprises a control system. However, the control system may be of any type (for example, a computer, a microcontroller, a mechanical system and so on).

In an embodiment, the control system is configured for closing each of the clamps by controlling the fluid dynamic system to supply the pressurized fluid to the corresponding closing transfer duct for a pressurization time of the downstream portion of the closing transfer duct and to interrupt said supplying the pressurized fluid to the closing transfer duct after the pressurization time. However, this result may be obtained in any way (for example, supplying the fluid under pressure at any pressure value for a pressurization time of any duration, with the closing transfer duct at any pressure value when the supply of the fluid under pressure is interrupted, even different from the atmospheric pressure, supplying the pressurized fluid subsequently for short intervals if necessary to re-establish the desired pressure value in the downstream portion of the transfer duct and so on).

Further embodiments provide additional advantageous features, which may however be omitted at all in a basic implementation.

In an embodiment, the bookbinding machine comprises corresponding opening transfer ducts. However, the opening transfer ducts may be of any type, shape and size (for example, either the same or different with respect to the closing transfer ducts), or they may even be completely missing when replaced by other opening systems of the clamps (for example, mechanical, magnetic and so on). In any case, the feature of the opening transfer ducts (in addition to the closing transfer ducts), stand-alone or together with any combination of the further related features, may also be used without the feature of the maintaining elements.

In an embodiment, the opening transfer ducts are for transferring the pressurized fluid to the clamps thereby acting thereon for opening. However, the pressurized fluid may act on each clamp for opening in any way (for example, in opposite directions on the same double-acting opening/closing actuators, through different opening actuators in any number and of any type, either the same or different with respect to the closing ones, by applying a pulling/pushing force of any value and so on).

In an embodiment, the rotary joint is further for supplying the pressurized fluid from the fluid dynamic system to each of the opening transfer ducts. However, this result may be obtained in any way (for example, with a cylinder for each clamp to which the corresponding closing/opening transfer ducts are connected, through separate cylinders for the closing transfer ducts and the opening transfer ducts, and so on).

In an embodiment, the control system is configured for opening each of the clamps by controlling the fluid dynamic system to supply the pressurized fluid to the corresponding opening supply duct. However, this result may be achieved in any way (for example, supplying the fluid under pressure at any pressure value, either the same or different with respect to the one used to close the clamp, for an opening time of any length or even until the clamp is to be closed, with the opening transfer duct at any pressure value when the supply of the pressurized fluid is interrupted, even different from the atmospheric pressure, for opening the clamp at different speeds or at a single speed, completely or partially, and so on).

In an embodiment, the maintaining devices have corresponding opening controls coupled with the corresponding opening transfer ducts. However, the possibility is not excluded of using maintaining devices with different type of control (for example, electromagnetic, electric and so on).

In an embodiment, in each of the clamps the pressurized fluid being transferred from the corresponding closing transfer duct acts on a closing surface and the pressurized fluid being transferred from the corresponding opening transfer duct acts on an opening surface greater than the closing surface. However, the closing/opening surfaces may have any value (in either relative or absolute terms) and they may be of any type (for example, opposite surfaces of double-acting actuators, distinct surfaces of different actuators and so on).

In an embodiment, the control system is configured for opening each of the clamps (for loading the corresponding book block) by controlling the fluid dynamic system to supply the pressurized fluid to the corresponding closing transfer duct and opening transfer duct at a same operative pressure, thereby applying a closing force to the clamp (by the pressurized fluid transferred from the closing transfer duct) and an opening force, opposite and higher than the closing force, to the clamp (by the pressurized fluid transferred from the opening transfer duct) that open the clamp at a loading speed. However, the operating pressure may be of any value and the opening/closing forces may have any value (either in relative or absolute terms) for opening the clamp at any loading speed. In any case, the possibility is not excluded of obtaining the same result in other ways (for example, supplying the fluid to the opening/closing transfer ducts at different pressure values, opening the non-return valve in a controlled way for reducing the corresponding pressure, and so on).

In an embodiment, the control system is configured for opening each of the clamps (for releasing the corresponding book block) by controlling the fluid dynamic system to supply the pressurized fluid to the corresponding opening transfer duct at the operative pressure without said supplying the pressurized fluid to the corresponding closing transfer duct, thereby opening the corresponding maintaining device (that discharges the pressurized fluid from the downstream portion of the closing transfer duct) and thereby applying the opening force to the clamp that opens the clamp at a releasing speed higher than the loading speed. However, the releasing speed may have any value (either with respect to the loading speed or in absolute terms). In any case, the possibility is not excluded of obtaining the same result in another way (for example, supplying the pressurized fluid to the opening transfer duct at a different operating pressure, opening the maintaining device independently of the pressurized fluid supplied to the opening transfer duct and so on).

In an embodiment, the maintaining devices are corresponding non-return valves. However, the non-return valves may be of any type (for example, with/without opening control, of ball-type, of diaphragm-type, of disc-type and so on).

In an embodiment, the bookbinding machine comprises corresponding discharging devices arranged in the downstream portions of the closing transfer ducts. However, the discharging devices may be of any type (for example, shut-off valves, controlled non-return valves and so on).

In an embodiment, each of the discharging devices is for discharging the pressurized fluid from the downstream portion of the corresponding closing transfer duct in response to a discharging command thereby freeing the corresponding clamp. However, the discharging command may be of any type (for example, electromagnetic, electric, pneumatic and the like, generated manually/automatically via a control element of any type and at any position, such as a button, a lever, an icon and so on) for freeing the clamp in any way (for example, with no force applied thereto for its manual opening, maintaining an opening force lower than the closing force being removed that opens the clamp automatically and so on).

In an embodiment, the rotary joint comprises a shaft and corresponding cylinders for the clamps being rotating around the shaft. However, the shaft and the cylinders may have any size and may be coupled in any way (for example, with any number and type of radial and/or thrust bearings, and so on).

In an embodiment, the rotary joint comprises corresponding fluid-tight closing grooves and possible opening grooves extending circumferentially between the cylinders and the shaft. However, the grooves may have any shape and size, they may be made in any way (for example, on the inner surface of the cylinders, on the outer surface of the shaft, on both of them and so on) and they may be kept fluid-tight in any way (for example, with gaskets in any number, of any material and so on).

In an embodiment, the shaft has corresponding closing supply ducts and possible opening supply ducts for the clamps (each for receiving the pressurized fluid from the fluid dynamic system). However, the supply ducts may be of any shape and size (for example, either the same or different between the closing supply ducts and the opening supply ducts).

In an embodiment, the closing supply ducts and the possible opening supply ducts extend along the shaft and end with corresponding closing mouths and opening mouths, respectively, being opened on a lateral surface of the shaft in front of the corresponding closing groove and opening groove, respectively. However, the (closing/opening) supply ducts may extend from a single end or from both ends of the shaft to any depth, and they may end with mouths of any shape and size (for example, either the same or different between the closing supply ducts and the opening supply ducts).

In an embodiment, the closing supply ducts and the possible opening supply ducts extend along the shaft in part from a first end and in part from a second end of the shaft. However, the (closing/opening) supply ducts may be distributed in any way between the two ends of the shaft (for example, in equal or different numbers, split so as to have the same length or not, split between closing supply ducts and opening supply ducts, and so on).

In an embodiment, the bookbinding machine comprises corresponding chains extending from the rotary joint to the corresponding clamps, the chains supporting the corresponding closing transfer ducts and possible opening transfer ducts. However, the chains may be of any type (for example, with any material, type of links and so on); in any case, the possibility is not excluded of providing other mechanical connections between the clamps and the rotary joint (for example, flexible/rigid connections such as metal bands, rods and so on), down to none at all (for example, in the case of sufficiently robust transfer ducts).

In an embodiment, the bookbinding machine comprises a resting plate arranged between the rotary joint and the clamps, the chains resting at least in part on the resting plate. However, the resting plate may be of any type (for example, shape, material, thickness, and so on) and the chains may rest thereon for any extent; in any case, the possibility is not excluded of having the chains (or other mechanical connections down to the transfer ducts alone) being suspended.

In an embodiment, each of the clamps comprises a plurality of fluid dynamic actuators being operated by the pressurized fluid to act on the clamp for closing and possibly for opening. However, the actuators may be in any number and of any type (for example, a plurality of double-acting actuators to act both for closing and for opening, a plurality of single-acting actuators to act for closing and a plurality of other single-acting actuators to act for opening, and so on) and they may be arranged at any position (for example, symmetrically with respect to a vertical axis, a horizontal axis and so on).

In an embodiment, the bookbinding machine is a perfect-binding machine. However, the perfect-binding machine may be of any type (for example, of automatic/manual type, for applying covers with or without endpapers/linings and so on).

An embodiment provides a distribution system for use in the bookbinding machine of above, wherein the distribution system comprises the rotary joint, the closing transfer ducts and the maintaining devices. However, the distribution system may comprise any of the above-mentioned further features (for example, the discharging devices, the opening transfer ducts, the chains and so on).

A further embodiment provides a bookbinding plant comprising one or more bookbinding machines of above. However, the bookbinding plant may be of any type (for example, with any number of these bookbinding machines and any number and type of further bookbinding machines, down to none, such as gathering machines, sewing machines, case-in machines, trimming machines and so on).

Generally, similar considerations apply if the bookbinding machine, the distribution system and the bookbinding plant each has a different structure, comprises equivalent components or has other operative characteristics, provided that it remains within the scope of the claims. In any case, every component thereof may be separated into more elements, or two or more components may be combined together into a single element; moreover, each component may be replicated to support the execution of the corresponding operations in parallel. Moreover, unless specified otherwise, any interaction between different components generally does not need to be continuous, and it may be either direct or indirect through one or more intermediaries.

A further embodiment provides a method for operating the bookbinding machine of above. In an embodiment, the method comprises closing each of the clamps by controlling the fluid dynamic system to supply the pressurized fluid to the corresponding closing transfer duct for a pressurization time of the downstream portion of the closing transfer duct and to interrupt said supplying the pressurized fluid to the closing transfer duct after the pressurization time. However, the method may comprise any further step corresponding to the above-mentioned features (for example, for discharging the pressurized fluid, for opening the clamps in general, at the loading speed, at the releasing speed and so on).

Generally, similar considerations apply if the same solution is implemented with an equivalent method, provided that it remains within the scope of the claims (by using similar steps with the same functions of more steps or portions thereof, removing some non-essential steps or adding further optional steps); moreover, the steps may be performed in a different order, concurrently or in an interleaved way (at least in part).

Claim 1:
A bookbinding machine (<NUM>) comprising one or more clamps (210a-210c) of fluid dynamic type for transporting book blocks, a fluid dynamic system (<NUM>) for supplying a pressurized fluid, corresponding closing transfer ducts (255a-255c) for transferring the pressurized fluid to the clamps (210a-210c) thereby acting thereon for closing, a rotary joint (<NUM>) for distributing the pressurized fluid from the fluid dynamic system (<NUM>) to each of the closing transfer ducts (255a-255c), a transport system (<NUM>) for transporting the clamps (210a-210c) around the rotary joint (<NUM>), wherein corresponding maintaining devices (545a-545c) are arranged along the closing transfer ducts (255a-255c) for maintaining the fluid under pressure in corresponding downstream portions of the closing transfer ducts (255a-255c), each being downstream of the corresponding maintaining device (545a-545c) along a transfer direction of the pressurized fluid from the rotary joint (<NUM>) to the corresponding clamp (210a-210c), and a control system (<NUM>) configured for closing each of the clamps (210a-210c) by controlling the fluid dynamic system (<NUM>) to supply the pressurized fluid to the corresponding closing transfer duct (255a-255c) for a pressurization time of the downstream portion of the closing transfer duct (255a-255c) and to interrupt said supplying the pressurized fluid to the closing transfer duct (255a-255c) after the pressurization time.