WO2013050821A1

WO2013050821A1 - A size press apparatus

Info

Publication number: WO2013050821A1
Application number: PCT/IB2012/000691
Authority: WO
Inventors: Gianni GENOVESIO
Original assignee: PMT Italia
Priority date: 2011-04-04
Filing date: 2012-04-04
Publication date: 2013-04-11

Abstract

A size press apparatus is disclosed for coating at least one surface of a web with a coating material. The size press apparatus includes a first roll for rotation about a first rotational axis, the first roll defining a first peripheral surface which is disposed spaced and parallel relative to the first rotational axis. A second roll is provided for rotation about a second rotational axis, the second roll defining a second peripheral surface which is disposed spaced and parallel relative to the second rotational axis. The first peripheral surface of the first roll cooperates with the second peripheral surface of the second roll for defining therebetween a nip for the passage therethrough of the web, the nip having a first nip line which extends between the first and second rotational axes of the first and second rolls respectively. A moving device moves the second rotational axis of the second roll. The moving device moves the second rotational axis from a first location thereof in which the nip is disposed on the first nip line to a second location of the second rotational axis in which the nip is defined between the first and second peripheral surfaces, the nip having a second nip line when in the second location thereof, the second nip line extending between the first and second axes of the first and second rolls respectively such that the first and second nip lines define therebetween a nip angle so that a variable nip angle is generated by the moving device when moving the second rotational axis of the second roll between the first and second locations thereof. The arrangement is such that a trajectory of the web exiting the nip remains relatively constant when moving the second rotational axis of the second roll between the first and second locations thereof.

Description

A SIZE PRESS APPARATUS.

Background of the invention. Field of the invention.

The present invention relates to a size press apparatus. More specifically, the present invention relates to a size press apparatus for coating at least one surface of a web with a coating material.

Background information.

A typical size press apparatus includes a movable top roll which cooperates with a fixed roll for defining therebetween a nip for the passage therethrough of a web of paper or the like.

A first coating head cooperates with a surface of the top roll such that when the top and fixed rolls counter rotate relative to each other, the first coating head applies coating material to the surface of the top roll such that the coating material on the surface of the top roll is applied to an adjacent surface of the web as the web passes through the nip. A second coater head also applies coating material to the rotating surface of the fixed roll such that this coating material is evenly applied to an opposite surface of the web during passage thereof through the nip.

The coating material when dry greatly enhances the subsequent printability of the surfaces of the resultant sized web. Various size compositions are used as the coating material according to the printing requirements of the resultant web and the properties of the web being sized.

In practice, in order to achieve an optimal size coating of the web, it has been found advantageous to slightly wrap the top roll by the web when exiting from the nip. In other applications, in order to achieve such optimal size coating conditions, it has been found beneficial to slightly wrap the fixed roll by the web when exiting from the nip. Alternatively, the web on exiting from the nip may wrap neither the top roll nor the fixed roll.

In prior art size presses, the trajectory of the web exiting from the nip was achieved by moving a movable paper guide roll disposed at a first position downstream from the nip. Movement of such movable roll would selectively change the web trajectory to wrap the top roll, wrap the fixed roll or wrap neither of the rolls so as to achieve such optimal coating configuration.

However, more recently, in the size press art, the movable guide roll has been replaced with a so called "air turn" which works on the physical principle of an air cushion. Such "air turn" has a great advantage over the prior art movable roll in that the "air turn" does not physically come into contact with either coated surfaces of the sized web. With the movable roll, at least one side of the wet coated surfaces would come into physical contact with the movable roll with certain detrimental results occurring therefrom. Nevertheless, with the advent of the "air turn" arrangement, there exists a problem in that the trajectory of the web between the coating nip and the "air turn" cannot be carried out in a simple fashion as was the case with the prior art movable roll. When an attempt is made to move the "air turn," the air flow of the "air turn" is altered thus creating operational difficulties with the management of the web trajectory downstream from the nip.

The concept of the present invention completely overcomes the aforementioned problems associated with the use of an "air turn" in the first position following the size press by selectively moving the fixed roll rather than the "air turn". By moving the "fixed roll", the fixed roll is selectively positioned so that the top roll and the "fixed roll" always define the coating nip therebetween while changing the wrap of the exiting web from wrapping the top roll, "fixed roll" or not wrapping either the top or the "fixed roll". A further advantage of the aforementioned arrangement is that the trajectory of the exiting web from the nip remains fairly constant regardless of the location of the "fixed roll" when moved through its variable nip angle.

Also, by the provision of the movable "fixed roll" according to the present invention, advantageous wrapping of the "fixed roll" immediately upstream from the nip may be achieved, a feature that was not attainable with the prior art movable roll arrangement.

Therefore, the primary feature of the present invention is the provision of a size press apparatus having a movable "fixed roll" which provides a variable nip angle which is particularly advantageous when used with an "air turn" disposed in a first position following a coating nip.

A further feature of the present invention is the provision of size press apparatus having a movable "fixed roll" which provides an arrangement for wrapping the "fixed roll" immediately upstream relative to the coating nip. Other features and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description of a preferred embodiment of the present invention contained herein.

Summary of the invention.

The present invention relates to a size press apparatus for coating at least one surface of a web with a coating material. The size press apparatus includes a first roll for rotation about a first rotational axis, the first roll defining a first peripheral surface which is disposed spaced and parallel relative to the first rotational axis. A second roll is provided for rotation about a second rotational axis, the second roll defining a second peripheral surface which is disposed spaced and parallel relative to the second rotational axis. A further moving device moves the first rotational axis of the first roll from a first disposition thereof in which the first peripheral surface is disposed a first distance from the second peripheral surface of the second roll such that positioning of the web between the first and second peripheral surfaces is permitted. The moving device moves the first rotational axis to a second disposition in which the first peripheral surface of the first roll cooperates with the second peripheral surface of the second roll for defining therebetween a nip for the passage therethrough of the web, the nip having a first nip line which extends between the first and second rotational axes of the first and second rolls respectively. A moving device moves the second rotational axis of the second roll when the first rotational axis of the first roll is in the second disposition thereof. The moving device moves the second rotational axis from a first location thereof in which the nip is disposed on the first nip line to a second location of the second rotational axis in which the nip is defined between the first and second peripheral surfaces, the nip having a second nip line when in the second location thereof, the second nip line extending between the first and second axes of the first and second rolls respectively such that the first and second nip lines define therebetween a nip angle so that a variable nip angle is generated by the moving device when moving the second rotational axis of the second roll between the first and second locations thereof. The arrangement is such that a trajectory of the web exiting the nip remains relatively constant when moving the second rotational axis of the second roll between the first and second locations thereof.

In a more specific embodiment of the present invention, the first roll is a top roll. Also, an applicator is connected to a source of the coating material. The applicator cooperates with the first peripheral surface of the first roll for applying the coating material to the first peripheral surface upstream relative to the nip such that when the web passes through the nip, the coating material is applied to a first surface defined by the web.

The second roll is a fixed roll in which the second rotational axis is disposed lower than the first rotational axis.

Furthermore, an application device is connected to a source of the coating material. The application device cooperates with the second peripheral surface of the second roll for applying the coating material to the second peripheral surface upstream relative to the nip such that when the web passes through the nip, the coating material is applied to a second surface defined by the web.

More specifically, the first roll rotates in a first rotational direction and the second roll rotates in a second rotational direction, the second rotational direction being opposite to the first rotational direction, the first rotational direction being a clockwise direction.

The apparatus includes a frame for rotatably supporting the first and second rolls.

Additionally, the further moving device includes a first arm which is pivotally secured to the frame about a first axis of rotation which is disposed parallel and spaced relative to the first rotational axis of the first roll. The first arm has a first and a second end, the first axis of rotation being disposed between the first and the second ends of the first arm.

A trunnion is defined by the first roll, the trunnion being rotatably supported by the first end of the arm such that the first roll rotates about the first rotational axis.

Moreover, a ram for moves the first arm, the ram having a first and a second extremity. The first extremity of the ram is secured to the second end of the first arm about a second axis of rotation and the second end of the ram is secured to the frame about a third axis of rotation. The arrangement is such that when the ram is energized, the first arm pivots about the first axis of rotation for moving the first rotational axis of the first roll between the first and second dispositions thereof. An applicator is connected to a source of the coating material. The applicator cooperates with the first peripheral surface of the first roll for applying the coating material to the first peripheral surface upstream relative to the nip. The arrangement is such that when the web passes through the nip, the coating material is applied to a first surface defined by the web.

Also, the applicator includes a second arm having a first and a second end. The first end of the second arm is secured to the first arm about a fourth axis of rotation. A link has a first and a second extremity. The second end of the second arm is secured to the link about a fifth axis of rotation which is disposed between the first and second extremities of the link.

The second extremity of the link is secured to the frame about a sixth axis of rotation and a third arm has a first and a second end. The first end of the third arm is pivotally secured to the first extremity of the link about a seventh axis of rotation.

Additionally, a further ram has a first and a second extremity, the first extremity of the further ram being secured to the second end of the third arm. The second extremity of the further ram is secured to the frame about an eighth axis of rotation. The further ram has a neutral mode of operation and an energized mode of operation.

An applicator head is secured to the third arm. The arrangement is such that when the further ram is in the neutral mode of operation and the first rotational axis of the first roll moves between the first and second dispositions thereof, the second arm, the link and the third arm cooperate together to maintain the applicator head in a first position in contact with the first peripheral surface of the first roll for an application thereto of the coating material. However, when the further ram is in the energized mode, the first extremity of the ram moves towards the first extremity of the ram for disengaging the applicator head from the first peripheral surface of the first roll.

Moreover, an application device is connected to a source of the coating material. The application device cooperates with the second peripheral surface of the second roll for applying the coating material to the second peripheral surface upstream relative to the nip such that when the web passes through the nip, the coating material is applied to a second surface defined by the web.

Furthermore, the moving device includes a lever having a first and a second end. the second end of the lever is secured to the frame about a third rotational axis. The third rotational axis is disposed between the first and second rotational axes. Also, the second roll defines a journal which is rotatably secured to the lever about a fourth rotational axis. The fourth rotational axis is disposed between the third rotational axis and the first end of the lever.

Additionally, a jack has a first and a second extremity. The first extremity of the jack is pivotally secured to the first end of the lever about a fifth rotational axis. The second extremity of the jack is pivotally secured to the frame about a sixth rotational axis. The arrangement is such that when the jack is operated, the lever is pivoted about the third rotational axis such that the second roll moves relative to the first roll while the first and second peripheral surfaces continue to define the nip therebetween. The arrangement is so that the first nip line between the first rotational axis and the second rotational axis when the second roll is in the first location thereof and the second nip line between the first rotational axis and the second rotational axis when the second roll is in the second location thereof define therebetween the variable nip angle.

The variable nip angle permits the web exiting the nip to selectively, wrap a variable portion of the first peripheral surface of the first roll or wrap a further variable portion of the second peripheral surface of the second roll or inhibit wrapping of either the first or the second peripheral surfaces of the rolls. This arrangement is provided so that an optimal coating disposition of the web exiting the nip is attained dependent on the variable nip angle.

Additionally, the variable nip angle permits wrapping of an upstream portion of the second peripheral surface of the second roll immediately upstream relative to the nip for further controlling and providing an optimal coating disposition of the web entering the nip.

The application device is pivotally secured to the first end of the lever about a seventh rotational axis;

Furthermore, an actuator has a first and a second extremity. The first extremity of the actuator is pivotally secured to the lever about an eighth rotational axis. The arrangement is such that the seventh rotational axis is disposed between the third rotational axis of the lever and the eighth rotational axis. The second extremity of the actuator is pivotally secured to the application device about a ninth rotational axis with the seventh and ninth rotational axes being spaced and parallel relative to each other. The arrangement is so that when the actuator is actuated, the application device is moved between an operative and an inoperative disposition thereof. Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings which show a preferred embodiment of the present invention. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims. Included in such modifications would be the application of the concept of the present invention to any type of size press including but not limited to puddle size presses. Such puddle size presses not only include cooperating rolls that have both axes of rotation disposed in a horizontal plane but also include cooperating rolls having both axes of rotation disposed in a plane which is not horizontal. Also included are a size press with at least one metering head or a puddle size press having a "fixed" top or bottom roll so that if the "fixed" roll is a top roll, such top "fixed" roll can be moved according to the concept disclosed in the present application.

Additionally, in the present invention, the lever which is disclosed in the preferred embodiment pivots about an axis which is disposed between the respective axes of the cooperating rolls. However, it is to be understood that the present invention as claimed includes also an arrangement in which the "fixed" roll is mounted on a sliding mechanism with the rotational axis of the fixed roll sliding in a direction which is disposed at an angle relative to the nip line

Brief description of the drawings. Fig. 1 is a side elevational view of a size press apparatus according to the present invention for coating at least one surface of a web with a coating material; Fig. 2 is a similar view to that shown in Fig. 1. However, Fig. 2 shows a further moving device having moved the first rotational axis to a second disposition thereof in which a first peripheral surface of a first roll cooperates with a second peripheral surface of a second roll for defining therebetween a nip for the passage therethrough of a web. Fig. 3 is a similar view to that shown in Fig. 2 but shows a moving device having moved a second rotational axis of the second roll to a second location thereof;

Fig. 4 is a similar view to that shown in Figs. 1-3 but shows a second rotational axis disposed between a first and second locations thereof as shown in Figs. 2 and 3 respectively; Fig. 5 is a similar view to that shown in Figs. 1-3 but shows a further ram shown in

Figs. 1-3 in an energized mode;

Fig. 6 is a diagrammatic view which is similar to Fig. 2 but on a larger scale;

Fig. 7 is a diagrammatic view which is similar to Fig. 3 but on a larger scale; and

Fig. 8 is a diagrammatic view which is similar to Fig. 4 but on a larger scale. Similar reference characters refer to similar parts throughout the various views of the drawings.

Detailed description of the drawings.

Fig. 1 is a side elevational view of a size press apparatus generally designated 10 for coating at least one surface of a web 12 with a coating material 14. As shown in Fig. 1, the size press apparatus 10 includes a first roll 16 for rotation about a first rotational axis 18, the first roll 16 defining a first peripheral surface 20 which is disposed spaced and parallel relative to the first rotational axis 18.

A second roll 22 is provided for rotation about a second rotational axis 24, the second roll 22 defining a second peripheral surface 26 which is disposed spaced and parallel relative to the second rotational axis 24. A moving device generally designate 30 moves the second rotational axis 24 of the second roll 22 and a further moving device generally designated 28 moves the first rotational axis 18 of the first roll 16 from a first disposition thereof as shown in Fig. 1 in which the first peripheral surface 20 is disposed a first distance D from the second peripheral surface 26 of the second roll 22 such that positioning of the web 12 between the first and second peripheral surfaces 20 and 26 respectively is permitted.

Fig. 2 is a similar view to that shown in Fig. 1. However, Fig. 2 shows the further moving device 28 having moved the first rotational axis 18 to a second disposition thereof in which the first peripheral surface 20 of the first roll 16 cooperates with the second peripheral surface 26 of the second roll 22 for defining therebetween a nip N for the passage therethrough of the web 12.

As shown in Fig. 2, the nip N has a first nip line NL1 which extends between the first and second rotational axes 18 and 24 of the first and second rolls 16 and 22 respectively. The moving device generally designate 30 moves the second rotational axis 24 of the second roll 22 when the first rotational axis 18 of the first roll 16 is in the second disposition thereof as shown in Fig. 2. The moving device 30 moves the second rotational axis 24 from a first location thereof as shown in Fig. 2. in which the nip N is disposed on the first nip line NL1. Fig. 3 is a similar view to that shown in Fig. 2 but shows the moving device 30 having moved the second rotational axis 24 of the second roll 22 to a second location of the second rotational axis 24 in which the nip N continues to be defined between the first and second peripheral surfaces 20 and 26 respectively, the nip N now being disposed on a second nip line NL2 when in the second location thereof as shown in Fig. 3. As shown in Fig. 3, the second nip line NL2 extends between the first and second axes 18 and 24 of the first and second rolls 16 and 22 respectively such that the first and second nip lines NL1 and NL2 define therebetween a nip angle NA so that a variable nip angle VNA is generated by the moving device 30 when moving the second rotational axis 24 of the second roll 22 between the first location as shown in Fig. 2 to the second location of the second rotational axis 24 as shown in Fig. 3. The arrangement is such that a trajectory T of the web 12 exiting the nip N remains relatively constant when moving the second rotational axis 24 of the second roll 22 between the first location as shown in Fig. 2 and the second location thereof as shown in Fig. 3.

In a more specific embodiment of the present invention, the first roll 16 is a top roll.

Also, as shown in Figs. 1-3, an applicator generally designated 32 is connected to a source 34 of the coating material 14 as shown in Fig. 2. The applicator 32 cooperates with the first peripheral surface 20 of the first roll 16 for applying the coating material 14 to the first peripheral surface 20 upstream relative to the nip N such that when the web 12 passes through the nip N, the coating material 14 is applied to a first surface 36 defined by the web 12.

The second roll 22 is a fixed roll in which the second rotational axis 24 is disposed lower than the first rotational axis 18. Furthermore, an application device generally designated 38 is connected to the source 34 of the coating material 14. The application device 38 cooperates with the second peripheral surface 26 of the second roll 22 for applying the coating material 14 to the second peripheral surface 26 upstream relative to the nip N such that when the web 12 passes through the nip N, the coating material 14 is applied to a second surface 40 defined by the web 12.

More specifically, the first roll 16 rotates in a first rotational direction as indicated by the arrow 42 shown in Figs. 1-3. Also, the second roll 22 rotates in a second rotational direction as indicated by the arrow 44, the second rotational direction 44 being opposite to the first rotational direction 42. The first rotational direction 42 is in a clockwise direction as viewed in Figs. 1-3.

The apparatus 10 includes a frame 46 for rotatably supporting the first and second rolls 16 and 22 respectively. Additionally, the further moving device 28 includes a first arm 48 which is pivotally secured to the frame 46 about a first axis of rotation 50 which is disposed parallel and spaced relative to the first rotational axis 18 of the first roll 16. The first arm 48 has a first and a second end 52 and 54 respectively, the first axis of rotation 50 being disposed between the first and the second ends 52 and 54 of the first arm 48.

A trunnion 56 is defined by the first roll 16, the trunnion 56 being rotatably supported by the first end 52 of the first arm 48 such that the first roll 16 rotates about the first rotational axis 18.

Moreover, a ram 58 is provided for moving the first arm 48, the ram 58 having a first and a second extremity 60 and 62 respectively. The first extremity 60 of the ram 58 is secured to the second end 54 of the first arm 48 about a second axis of rotation 64 and the second end 62 of the ram 58 is secured to the frame 46 about a third axis of rotation 66. The arrangement is such that when the ram 58 is energized, the first arm 48 pivots about the first axis of rotation 50 for moving the first rotational axis 18 of the first roll 16 between the first disposition as shown in Fig. 1 to the second disposition of the first rotational axis 18 as shown in Fig. 2.

Also, the applicator 32 includes a second arm 68 having a first and a second end 70 and 72 respectively. The first end 70 of the second arm 68 is secured to the first arm 48 about a fourth axis of rotation 74. As shown in Fig. 2, a link 76 has a first and a second extremity 78 and 80 respectively. The second end 72 of the second arm 68 is secured to the link 76 about a fifth axis of rotation 82 which is disposed between the first and second extremities 78 and 80 respectively of the link 76.

The second extremity 80 of the link 76 is secured to the frame 46 about a sixth axis of rotation 84. Also, a third arm 86 has a first and a second end 88 and 90 respectively. The first end 88 of the third arm 86 is pivotally secured to the first extremity 78 of the link 76 about a seventh axis of rotation 92. Additionally, as shown in Fig. 3, a further ram 94 has a first and a second extremity 96 and 98 respectively. The first extremity 96 of the further ram 94 is secured to the second end 90 of the third arm 86. The second extremity 98 of the further ram 94 is secured to the frame 46 about an eighth axis of rotation 100. The further ram 94 has a neutral mode of operation and an energized mode of operation.

An applicator head 102 is secured to the third arm 86. The arrangement is such that when the further ram 94 is in the neutral mode of operation and the first rotational axis 18 of the first roll 16 moves between the first disposition as shown in Fig. 1 to the second disposition of the first rotational axis 18 as shown in Fig. 2, the second arm 68, the link 76 and the third arm 86 cooperate together to maintain the applicator headl02 in a first position in contact with the first peripheral surface 20 of the first roll 16 for an application thereto of the coating material 14 as shown in Figs. 1-3.

Furthermore, the moving device 30 includes a lever 104 as shown in Fig. 3 having a first and a second end 106 and 108 respectively. The second end 108 of the leverl04 is secured to the frame 46 about a third rotational axis 1 10. The third rotational axis 110 is disposed between the first and second rotational axes 18 and 24 respectively. Also, the second roll 22 defines a journal 1 12 which is rotatably secured to the lever 104 about the second rotational axis 24. The second rotational axis 24 is disposed between the third rotational axis 1 10 and the first end 106 of the lever 104. Fig. 4 is a similar view to that shown in Figs. 1-3 but shows the second rotational axis 24 disposed between the first and second locations thereof as shown in Figs. 2 and 3 respectively. As shown in Fig. 4, the third rotational axis 1 10 of the lever 104 is disposed at an intersection of a straight line L which extends through the first and second rotational axes 18 and 24 of the first and second rolls 16 and 22 and the first peripheral surface 20 of the first roll 16 when the first rotational axis 18 is in said second disposition thereof. The arrangement is such that as the second roll 22 is moved, the top roll 16 micro moves to compensate for movement of the second roll 22 so that regardless of the angular disposition of the lever 104 about the third rotational axis 110 thereof, the second peripheral surface 26 of the second roll 22 will always cooperate with the first peripheral surface 20 of the first roll 16 to define the nip N therebetween. Such micro movement of the top roll 16 can be controlled by the ram 58. Also, such micro movement of the first roll 16 when in the second disposition thereof compensates for any change in diameter of the rolls 16 and 22 or any roll covers thereon due to wear during usage of the size press apparatus 10.

Additionally, as shown in Fig. 4, a jack 116 has a first and a second extremity 118 and 120 respectively. The first extremity 1 18 of the jack 1 16 is pivotally secured to the first end 106 of the lever 104 about a fifth rotational axis 122. The second extremity 120 of the jack 1 16 is pivotally secured to the frame 46 about a sixth rotational axis 124. The arrangement is such that when the jack 1 16 is operated, the lever 104 is pivoted about the third rotational axis 1 10 such that the second roll 22 moves relative to the first roll 16 while the first and second peripheral surfaces 20 and 26 continue to define the nip N therebetween. The arrangement is so that the first nip line NL1 and the second nip line NL2 shown in Figs. 2 and 3 define a variable nip angle VNA therebetween. More specifically, as shown in Figs. 2 and 3, the first nip line NL1 extends between the first rotational axis 18 and the second rotational axis 24 when the second roll 22 is the first location thereof as shown in Fig. 2. The second nip line NL2 shown in Fig. 3 extends between the first rotational axis 18 and the second rotational axis 24 when the second roll 22 is in the second location thereof as shown in Fig. 3. Thus, the first and second nip lines NL1 and NL2 define the variable nip angle VNA therebetween.

The variable nip angle VNA only slightly moves the trajectory T of the web 12 exiting the nip N to the "air turn" AT as shown in Figs. 2 and 3.

As shown in Fig. 4, the application device 38 is pivotally secured to the first end 106 of the lever 104 about a seventh rotational axis 126. Furthermore, an actuator 128 has a first and a second extremity 130 and 132 respectively. The first extremity 130 of the actuator 128 is pivotally secured to the lever 104 about an eighth rotational axis 134. The arrangement is such that the seventh rotational axis 126 is disposed between the third rotational axis 1 10 of the lever 104 and the eighth rotational axis 134. The second extremity 132 of the actuator 128 is pivo tally secured to the application device 38 about a ninth rotational axis 136 with the seventh and ninth rotational axes 126 and 136 respectively being spaced and parallel relative to each other.

Fig. 5 is a similar view to that shown in Figs. 1-3 but shows the further ram 94 in an energized mode. As shown in Fig. 5, the further ram 94 is in the energized mode with the first extremity 96 of the further ram 94 moved towards the second 98 extremity of the further ram 94 for disengaging the applicator head 102 from the first peripheral surface 20 of the first roll 16 as shown in Fig. 5.

Additionally, as shown in Fig. 5, the arrangement is such that when the actuator 128 is actuated, the application device 38 is moved between an operative disposition as shown in Figs. 1 -4 to an inoperative disposition thereof as shown in Fig. 5.

Fig. 6 is a diagrammatic view which is similar to Fig. 2 but on a larger scale. As shown in Fig. 6 which corresponds to the first location of the second rotational axis 24 as shown in Fig. 2, the web 12 wraps around a first portion DP20 of the first peripheral surface 20 of the first roll 16 downstream relative to the nip N.

Fig. 7 is a diagrammatic view which is similar to Fig. 3 but on a larger scale. As shown in Fig. 7 which corresponds to the second location of the second rotational axis 24 as shown in Fig. 3, the web 12 wraps a second portion DP26 of the second peripheral surface 26 of the second roll 22 downstream relative to the nip N. Fig. 8 is a diagrammatic view which is similar to Fig. 4 but on a larger scale. As shown in Fig. 8 which corresponds to a location of the second rotational axis 24 which is between the first and second locations shown in Figs. 6 and 7 respectively. As shown in Fig. 8, the web 12 does not wrap around either the peripheral surface 20 or the peripheral surface 26 downstream relative to the nip N.

As shown in Fig. 6, the web 12 also wraps around a third portion UP26 of the second peripheral surface 26 of the second roll 22 upstream relative to the nip N. Also, as shown in Fig. 7, the web 12 also wraps around a fourth portion UP20 of the first peripheral surface 20 of the first roll 16 upstream relative to the nip N.

In operation of the size press apparatus 10, the web 12 is loaded and correctly positioned between the top roll 16 and the "fixed roll" 22 when the top roll 16 is the first disposition thereof as shown in Fig. 1.

The top roll 16 is then lowered to the second disposition thereof as shown in Fig. 2 so that the first peripheral surface 20 of the top roll 16 cooperates with the second peripheral surface 26 of the "fixed roll" 22 to define the nip N therebetween.

As the web 12 passes through the counter rotating rolls 16 and 22, the application head 102 is moved from the inoperative mode shown in Fig. 5 to the operative mode thereof as shown in Figs. 1 -4. Also, the actuator 128 moves the other coating head of the application device 38 from the inoperative disposition thereof as shown in Fig. 5 to the operative disposition so that size 14 is applied to the second peripheral surface 26 for application thereof to the second surface 40 of the web 12 during passage thereof through the nip N.

The optimal coating configuration of the size press apparatus 10 is achieved by means of the moving device 30 which moves the "fixed roll" through the variable nip angle VNA with the first and second peripheral surfaces 20 and 26 always defining the nip N therebetween when the top roll 16 is in the second disposition thereof. The present invention provides a unique arrangement for changing the location of the nip in a size press apparatus for obtaining an optimal size coating of the web.

Claims

1.A size press apparatus for coating at least one surface of a web with a coating material, said size press apparatus comprising: a first roll for rotation about a first rotational axis, said first roll defining a first peripheral surface which is disposed spaced and parallel relative to said first rotational axis; a second roll for rotation about a second rotational axis, said second rotational axis being disposed spaced and parallel relative to said first rotational axis, said second roll defining a second peripheral surface which is disposed spaced and parallel relative to said second rotational axis; said first peripheral surface of said first roll cooperating with said second peripheral surface of said second roll for defining therebetween a nip for the passage therethrough of the web, said nip having a first nip line which extends between said first and second rotational axes of said first and second rolls respectively; and a moving device for moving said second rotational axis of said second roll from a first location thereof in which said nip has said first nip line to a second location of said second rotational axis in which said nip is defined between said first and second peripheral surfaces, said nip having a second nip line when in said second location thereof, said second nip line extending between said first and second axes of said first and second rolls respectively such that said first and second nip lines define therebetween a nip angle so that a variable nip angle is generated by said moving device when moving said second rotational axis of said second roll between said first and second locations thereof so that a trajectory of the web exiting said nip remains relatively constant when moving said second rotational axis of said second roll between said first and second locations thereof.

2. A size press apparatus as set forth in claim 1 further including: a further moving device for moving said first rotational axis of said first roll from a first disposition thereof in which said first peripheral surface is disposed a first distance from said second peripheral surface of said second roll such that positioning of the web between said first and second peripheral surfaces is permitted to a second disposition of said first rotational axis of said first roll in which said first peripheral surface of said first roll cooperates with said second peripheral surface of said second roll for defining therebetween said nip for the passage therethrough of the web; said moving device moving said second rotational axis of said second roll when said first rotational axis of said first roll is in said second disposition thereof.

3. A size press apparatus as set forth in claim 2 wherein said first roll is a top roll

4. A size press apparatus as set forth in claim 2 further including: an applicator connected to a source of the coating material, said applicator cooperating with said first peripheral surface of said first roll for applying the coating material to said first peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating is applied to a first surface defined by the web.

5. A size press apparatus as set forth in claim 2 wherein said second roll is a fixed roll in which said second rotational axis is disposed lower than said first rotational axis.

6. A size press apparatus as set forth in claim 2 further including: an application device connected to a source of the coating material, said application device cooperating with said second peripheral surface of said second roll for applying the coating material to said second peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating material is applied to a second surface defined by the web.

7. A size press apparatus as set forth in claim 2 wherein said first roll rotates in a first rotational direction; said second roll rotates in a second rotational direction, said second rotational direction being opposite to said first rotational direction.

8. A size press apparatus as set forth in claim 7 wherein said first rotational direction is a clockwise direction.

9. A size press apparatus as set forth in claim 2 further including: a frame for rotatably supporting said first and second rolls; said further moving device including: a first arm pivotally secured to said frame about a first axis of rotation which is disposed parallel and spaced relative to said first rotational axis of said first roll, said first arm having a first and a second end, said first axis of rotation being disposed between said first and said second ends of said first arm; a trunnion defined by said first roll, said trunnion being rotatably supported by said first end of said arm such that said first roll rotates about said first rotational axis; a ram for moving said first arm, said ram having a first and a second extremity, said first extremity of said ram being secured to said second end of said first arm about a second axis of rotation, said second end of said ram being secured to said frame about a third axis of rotation, so that when said ram is energized, said first arm pivots about said first axis of rotation for moving said first rotational axis of said first roll between said first and second dispositions thereof.

10. A size press apparatus as set forth in claim 9 further including: an applicator connected to a source of the coating material, said applicator cooperating with said first peripheral surface of said first roll for applying the coating material to said first peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating material is applied to a first surface defined by the web; said applicator including: a second arm having a first and a second end, said first end of said second arm being secured to said first arm about a fourth axis of rotation; a link having a first and a second extremity, said second end of said second arm being secured to said link about a fifth axis of rotation which is disposed between said first and second extremities of said link; said second extremity of said link being secured to said frame about a sixth axis of rotation: a third arm having a first and a second end, said first end of said third arm being pivotally secured to said first extremity of said link about a seventh axis of rotation; a further ram having a first and a second extremity, said first extremity of said further ram being secured to said second end of said third arm, said second extremity of said further ram being secured to said frame about an eighth axis of rotation, said further ram having a neutral mode of operation and an energized mode of operation; an applicator head secured to said third arm such that when said further ram is in said neutral mode of operation and said first rotational axis of said first roll moves between said first and second dispositions thereof, said second arm, said link and said third arm cooperate together to maintain said applicator head in a first position in contact with said first peripheral surface of said first roll for an application thereto of the coating material, however when said further ram is in said energized mode, said first extremity of said ram moves towards said first extremity of said ram for disengaging said applicator head from said first peripheral surface of said first roll.

11.A size press apparatus as set forth in claim 2 further including: an application device connected to a source of the coating material, said application device cooperating with said second peripheral surface of said second roll for applying the coating material to said second peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating material is applied to a second surface defined by the web; a frame for rotatably supporting said first and second rolls; said moving device including: a lever having a first and a second end, said second end of said lever being secured to said frame about a third rotational axis, said third rotational axis being disposed between said first and second rotational axes, said second roll defining a journal which is rotatably secured to said lever about a fourth rotational axis, said fourth rotational axis being disposed between said third rotational axis and said first end of said lever; a jack having a first and a second extremity, said first extremity of said jack being pivotally secured to said first end of said lever about a fifth rotational axis, said second extremity of said jack being pivotally secured to said frame about a sixth rotational axis, the arrangement being such that when said jack is operated, said lever is pivoted about said third rotational axis such that said second roll moves relative to said first roll while said first and second peripheral surfaces continue to define said nip therebetween so that said first nip line between said first rotational axis and said second rotational axis when said second roll is in said first location thereof and said second nip line between said first rotational axis and said second rotational axis when said second roll is in said second location thereof define therebetween said variable nip angle.

12.A size press apparatus as set forth in claim 1 wherein said moving device includes: a sliding mechanism for rotatably supporting said second roll such that said sliding mechanism slides said second rotational axis in a direction which disposed at an angle relative to said first nip line.

13.A size press apparatus as set forth in claim 11 wherein said variable nip angle permits the web exiting said nip to selectively, wrap a variable portion of said first peripheral surface of said first roll, wrap a further variable portion of said second peripheral surface of said second roll, and to inhibit wrapping of either said first and second peripheral surfaces of said rolls so that an optimal coating disposition of the web exiting said nip is attained dependent on said variable nip angle.

14. A size press apparatus as set forth in claim 13 wherein said variable nip angle permits selective wrapping of an upstream portions of said first and second peripheral surfaces of said first and second rolls immediately upstream relative to said nip for further controlling and providing an optimal coating disposition of the web entering said nip.

15. A size press apparatus as set forth in claim 14 wherein said application device is pivotally secured to said first end of said lever about a seventh rotational axis; an actuator having a first and a second extremity, said first extremity of said actuator being pivotally secured to said lever about an eighth rotational axis such that said seventh rotational axis is disposed between said third rotational axis of said lever and said eighth rotational axis, said second extremity of said actuator being pivotally secured to said application device about a ninth rotational axis with said seventh and ninth rotational axes being spaced and parallel relative to each other so that when said actuator is actuated, said application device is moved between an operative and an inoperative disposition thereof.

16. A size press apparatus for coating at least one surface of a web with a coating material, said size press apparatus comprising: a first roll for rotation about a first rotational axis, said first roll defining a first peripheral surface which is disposed spaced and parallel relative to said first rotational axis; a second roll for rotation about a second rotational axis, said second rotational axis being disposed spaced and parallel relative to said first rotational axis, said second roll defining a second peripheral surface which is disposed spaced and parallel relative to said second rotational axis; a further moving device for moving said first rotational axis of said first roll from a first disposition thereof in which said first peripheral surface is disposed a first distance from said second peripheral surface of said second roll such that positioning of the web between said first and second peripheral surfaces is permitted to a second disposition of said first rotational axis of said first roll in which said first peripheral surface of said first roll cooperates with said second peripheral surface of said second roll for defining therebetween a nip for the passage therethrough of the web, said nip having a first nip line which extends between said first and second rotational axes of said first and second rolls respectively; a moving device for moving said second rotational axis of said second roll when said first rotational axis of said first roll is in said second disposition thereof, said moving device moving said second rotational axis from a first location thereof in which said nip has said first nip line to a second location of said second rotational axis in which said nip is defined between said first and second peripheral surfaces, said nip having a second nip line when in said second location thereof, said second nip line extending between said first and second axes of said first and second rolls respectively such that said first and second nip lines define therebetween a nip angle so that a variable nip angle is generated by said moving device when moving said second rotational axis of said second roll between said first and second locations thereof so that a trajectory of the web exiting said nip remains relatively constant when moving said second rotational axis of said second roll between said first and second locations thereof; and said variable nip angle permitting the web exiting said nip to selectively, wrap a variable portion of said first peripheral surface of said first roll, wrap a further variable portion of said second peripheral surface of said second roll, and to inhibit wrapping of either said first and second peripheral surfaces of said rolls so that an optimal coating disposition of the web exiting said nip is attained dependent on said variable nip angle.

17. A size press apparatus for coating at least one surface of a web with a coating material, said size press apparatus comprising: a first roll for rotation about a first rotational axis, said first roll defining a first peripheral surface which is disposed spaced and parallel relative to said first rotational axis; a second roll for rotation about a second rotational axis, said second rotational axis being disposed spaced and parallel relative to said first rotational axis, said second roll defining a second peripheral surface which is disposed spaced and parallel relative to said second rotational axis; a further moving device for moving said first rotational axis of said first roll from a first disposition thereof in which said first peripheral surface is disposed a first distance from said second peripheral surface of said second roll such that positioning of the web between said first and second peripheral surfaces is permitted to a second disposition of said first rotational axis of said first roll in which said first peripheral surface of said first roll cooperates with said second peripheral surface of said second roll for defining therebetween a nip for the passage therethrough of the web, said nip having a first nip line which extends between said first and second rotational axes of said first and second rolls respectively; a moving device for moving said second rotational axis of said second roll when said first rotational axis of said first roll is in said second disposition thereof, said moving device moving said second rotational axis from a first location thereof in which said nip has said first nip line to a second location of said second rotational axis in which said nip is defined between said first and second peripheral surfaces, said nip having a second nip line when in said second location thereof, said second nip line extending between said first and second axes of said first and second rolls respectively such that said first and second nip lines define therebetween a nip angle so that a variable nip angle is generated by said moving device when moving said second rotational axis of said second roll between said first and second locations thereof so that a trajectory of the web exiting said nip remains relatively constant when moving said second rotational axis of said second roll between said first and second locations thereof; a frame for rotatably supporting said first and second rolls; a lever having a first and a second end, said second end of said lever being secured to said frame about a third rotational axis, said third rotational axis lying on a straight line which extends through said first and second rotational axes of said first and second rolls, said third rotational axis also lying on said first peripheral surface of said first roll when said first rotational axis is in said second disposition thereof, the arrangement being such that regardless of an angular disposition of said lever about said third rotational axis thereof, said second peripheral surface of said second roll will always cooperate with said first peripheral surface of said first roll to define said nip therebetween.

18. A size press apparatus for coating at least one surface of a web with a coating material, said size press apparatus comprising: a first roll for rotation about a first rotational axis, said first roll defining a first peripheral surface which is disposed spaced and parallel relative to said first rotational axis; a second roll for rotation about a second rotational axis, said second rotational axis being disposed spaced and parallel relative to said first rotational axis, said second roll defining a second peripheral surface which is disposed spaced and parallel relative to said second rotational axis; a moving device for moving said second rotational axis of said second roll; a further moving device for moving said first rotational axis of said first roll from a first disposition thereof in which said first peripheral surface is disposed a first distance from said second peripheral surface of said second roll such that positioning of the web between said first and second peripheral surfaces is permitted to a second disposition of said first rotational axis of said first roll in which said first peripheral surface of said first roll cooperates with said second peripheral surface of said second roll for defining therebetween a nip for the passage therethrough of the web, said nip having a first nip line which extends between said first and second rotational axes of said first and second rolls respectively; said moving device moving said second rotational axis of said second roll when said first rotational axis of said first roll is in said second disposition thereof, said moving device moving said second rotational axis from a first location thereof in which said nip has said first nip line to a second location of said second rotational axis in which said nip is defined between said first and second peripheral surfaces, said nip having a second nip line when in said second location thereof, said second nip line extending between said first and second axes of said first and second rolls respectively such that said first and second nip lines define therebetween a nip angle so that a variable nip angle is generated by said moving device when moving said second rotational axis of said second roll between said first and second locations thereof so that a trajectory of the web exiting said nip remains relatively constant when moving said second rotational axis of said second roll between said first and second locations thereof; said first roll being a top roll; an applicator connected to a source of the coating material, said applicator cooperating with said first peripheral surface of said first roll for applying the coating material to said first peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating is applied to a first surface defined by the web; said second roll being a fixed roll in which said second rotational axis is disposed lower than said first rotational axis; an application device connected to a source of the coating material, said application device cooperating with said second peripheral surface of said second roll for applying the coating material to said second peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating material is applied to a second surface defined by the web; said first roll rotates in a first rotational direction; said second roll rotates in a second rotational direction, said second rotational direction being opposite to said first rotational direction; said first rotational direction is a clockwise direction; a frame for rotatably supporting said first and second rolls; said further moving device including: a first arm pivotally secured to said frame about a first axis of rotation which is disposed parallel and spaced relative to said first rotational axis of said first roll, said first arm having a first and a second end, said first axis of rotation being disposed between said first and said second ends of said first arm; a trunnion defined by said first roll, said trunnion being rotatably supported by said first end of said arm such that said first roll rotates about said first rotational axis; a ram for moving said first arm, said ram having a first and a second extremity, said first extremity of said ram being secured to said second end of said first arm about a second axis of rotation, said second end of said ram being secured to said frame about a third axis of rotation, so that when said ram is energized, said first arm pivots about said first axis of rotation for moving said first rotational axis of said first roll between said first and second dispositions thereof; an applicator connected to a source of the coating material, said applicator cooperating with said first peripheral surface of said first roll for applying the coating material to said first peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating material is applied to a first surface defined by the web; said applicator including: a second arm having a first and a second end, said first end of said second arm being secured to said first arm about a fourth axis of rotation; a link having a first and a second extremity, said second end of said second arm being secured to said link about a fifth axis of rotation which is disposed between said first and second extremities of said link; said second extremity of said link being secured to said frame about a sixth axis of rotation: a third arm having a first and a second end, said first end of said third arm being pivotally secured to said first extremity of said link about a seventh axis of rotation; a further ram having a first and a second extremity, said first extremity of said further ram being secured to said second end of said third arm, said second extremity of said further ram being secured to said frame about an eighth axis of rotation, said further ram having a neutral mode of operation and an energized mode of operation; an applicator head secured to said third arm such that when said further ram is in said neutral mode of operation and said first rotational axis of said first roll moves between said first and second dispositions thereof, said second arm, said link and said third arm cooperate together to maintain said applicator head in a first position in contact with said first peripheral surface of said first roll for an application thereto of the coating material, however when said further ram is in said energized mode, said first extremity of said ram moves towards said first extremity of said ram for disengaging said applicator head from said first peripheral surface of said first roll; an application device connected to a source of the coating material, said application device cooperating with said second peripheral surface of said second roll for applying the coating material to said second peripheral surface upstream relative to said nip such that when the web passes through said nip, the coating material is applied to a second surface defined by the web; said moving device including: a lever having a first and a second end, said second end of said lever being secured to said frame about a third rotational axis, said third rotational axis being disposed between said first and second rotational axes, said second roll defining a journal which is rotatably secured to said lever about a fourth rotational axis, said fourth rotational axis being disposed between said third rotational axis and said first end of said lever; a jack having a first and a second extremity, said first extremity of said jack being pivotally secured to said first end of said lever about a fifth rotational axis, said second extremity of said jack being pivotally secured to said frame about a sixth rotational axis, the arrangement being such that when said jack is operated, said lever is pivoted about said third rotational axis such that said second roll moves relative to said first roll while said first and second peripheral surfaces continue to define said nip therebetween so that said first nip line between said first rotational axis and said second rotational axis when said second roll is in said first location thereof and said second nip line between said first rotational axis and said second rotational axis when said second roll is in said second location thereof define therebetween said variable nip angle; said variable nip angle permitting the web exiting said nip to selectively, wrap a variable portion of said first peripheral surface of said first roll, wrap a further variable portion of said second peripheral surface of said second roll, and to inhibit wrapping of either said first and second peripheral surfaces of said rolls so that an optimal coating disposition of the web exiting said nip is attained dependent on said variable nip angle; said variable nip angle permitting wrapping of an upstream portion of said surface further controlling and providing an optimal coating disposition of the web entering said nip; said application device being pivotally secured to said first end of said lever about a seventh rotational axis; and an actuator having a first and a second extremity, said first extremity of said actuator being pivotally secured to said lever about an eighth rotational axis such that said seventh rotational axis is disposed between said third rotational axis of said lever and said eighth rotational axis, said second extremity of said actuator being pivotally secured to said application device about a ninth rotational axis with said seventh and ninth rotational axes being spaced and parallel relative to each other so that when said actuator is actuated, said application device is moved between an operative and an inoperative disposition thereof.