WO1997011017A1

WO1997011017A1 - Sheet feeding device for a sheet processing line

Info

Publication number: WO1997011017A1
Application number: PCT/FR1996/001448
Authority: WO
Inventors: Bernard Guiot
Original assignee: Rapidex Sm
Priority date: 1995-09-18
Filing date: 1996-09-18
Publication date: 1997-03-27
Also published as: FR2738807B1; FR2738807A1

Abstract

A sheet feeding device for a sheet processing line, including sheet transporting and feeding means (14, 16) for transporting and feeding a sheet into the processing line, and delivery means for delivering the lowermost sheet in a stack to said transporting and feeding means, comprising rotary members (20, 22, 24) aligned in the sheet feeding direction (f), located upstream from the transporting and feeding means, and arranged in a suction housing (26). The rotary members project from the top (27) of the suction housing (26) and are capable at all times of engaging the lowermost sheet (12a) in the stack (12). Drive means for rotating the rotary members include a speed generator (40) with an output connected to the main line motor, and, for each of said rotary members, a mechanical clutch system and a braking system that may be selectively activated and deactivated depending on the position of the lowermost sheet in the stack relative to the rotary members. The speed generator generates a speed curve that includes an acceleration period, a constant-speed drive period and a deceleration period.

Description

Sheet feeding device in a sheet processing line

The present invention relates to a device for feeding sheets into a line for processing these sheets. The device comprises a receiving location for a stack of sheets, means for transporting and introducing a sheet into the processing line and means for feeding the bottom sheet of the stack to said means of transport and introduction. The supply means comprise at least a first and a second rotary member placed, one after the other in the direction of transport of the sheets, upstream of the transport and introduction means, arranged in a suction box located under the receiving location and likely to come into contact with the bottom sheet of the stack. The device further comprises means for driving the rotary members in rotation. The sheets can be of more or less thick paper, cardboard, corrugated cardboard or the like. The processing line conventionally comprises several processing modules arranged one after the other in the direction of transport of the sheets, in order to carry out several successive operations on these sheets. It can, for example, be a line for manufacturing cardboard packaging, which includes a feeder module (constituting the feed device), one or more printer modules, a slitting and creasing module, and a cutter module. Each module has one or more rotating members which perform its function.

The feeder must feed the sheets one by one, respecting the line's processing rate. The means of transport and introduction of a sheet into the processing line are driven by a constant transport speed, equal to the overall speed of the line. The role of the feeding means is to select the bottom sheet of the stack, to set it in motion towards the means of transport and introduction, gradually giving it a speed which, at the end of this acceleration phase, must be substantially equal to the speed of transport, and to bring this sheet to the means of transport and introduction so that they take over and introduce the sheet, at the speed of transport, into the module of the line treatment which is placed immediately downstream of the feeding device. In known devices, for example by US Pat. No. 4,614,335, the receiving location comprises a vertically movable sheet support between a low position, in which the rotary members pass partially through this support and come into contact with the sheet. lower, and a high position in which they raise the stack of sheets so that it escapes the rotating members. The operating cycle of this known device is as follows:

- at the start of the cycle, the rotary members are stopped and the support occupies its high position; - Firstly, the support is lowered so that the bottom sheet of the stack comes into contact with the rotary members, which are always stopped;

- In a second step, the rotary members are gradually accelerated to set the lower sheet in motion until giving it a speed substantially equal to the transport speed;

- the speed of rotation of the rotary members then remains constant to bring the bottom sheet to the means of transport and introduction (depending on the case, these means of transport and introduction can take over from the rotary members, or the sheet can be, over a short distance, driven simultaneously by the means of transport and introduction and by the rotary members);

- then, before the rear edge of the lower sheet reaches the level of the most upstream rotary member, the support is raised to its high position so that all the sheets escape the rotary members, the lower sheet is then only driven by the transport and introduction means and, insofar as the rear part of this sheet is disposed between the support and the other sheets of the stack, these transport and introduction means must overcome the friction forces which are exerted on this rear part; - Finally, the rotary members are stopped to place the assembly in the starting position for a new cycle.

A first drawback of this type of feeding device lies in the fact that, when the lower sheet is only driven by the means of transport and introduction but its rear part remains between the support and the other sheets of the stack, significant friction forces must be overcome, which implies that these means of transport and introduction, generally consisting of two opposite cylinders rotating in opposite directions, pinch this sheet very strongly. This pinching can cause unsightly traces and, especially when the sheet is made of corrugated cardboard, locally crush the cardboard. In addition, the sheet must be strong enough to withstand the tensile stresses to which it is subjected on this occasion.

It should also be noted that the vertical displacement of the support is an essential element of the feeding cycle. It is therefore necessary to provide, in addition to the system for controlling the rotation of the rotary members, a system for controlling the vertical movement of the support, and to perfectly synchronize these two control systems. The implementation of this device is therefore complex and the cost price of its manufacture is high.

Furthermore, from documents EP 379 306 and EP 612 679, devices are known in which the need to vertically move the sheet support is overcome.

In these devices, the location for the stack of sheets has a given lower level capable of being occupied by the lower sheet of the stack and the rotary members protrude beyond the upper end of the suction box, substantially up to 'at this lower level, and are permanently liable to come into contact with the lower sheet of the stack.

In document EP 379 306, an independent electric motor is used for each rotary member. Thus, it is only possible to correctly synchronize the rotations and stops of these motors by having recourse to a sophisticated electronic control system. In addition, these engines must be able to accelerate and decelerate in a very short time. This requirement for high performance and complexity of electronics considerably increases the manufacturing costs of these devices.

Overall, the same arrangement is chosen from document EP 612 679. However, this document alternatively provides that the rotation drive means comprise a motor and, for each rotary member, a mechanical clutch system capable of being activated for engage the rotary member and be deactivated to disengage said rotary member, as well as a brake system capable of being activated to brake the rotary member and to be deactivated to release said member, the rotary drive means further comprising means for controlling the clutch systems and means for controlling the brake systems. This document also indicates that with this variant, the deceleration and stopping sequence would be obtained by actuating the brake systems successively, then the motor.

Thus, the engine must be braked to a stop, then restarted and accelerated to start a new cycle. To play its role, this engine must be able to accelerate and decelerate in a very short time. It is therefore still a high performance engine, with a high cost price. In addition, the very presence of this independent motor, in addition to all the elements of the kinematics of the sheet processing line constitutes a factor of increase in the price. The present invention aims to remedy the drawbacks of the aforementioned prior art.

This object is achieved thanks to the fact that, the means of transporting and introducing a sheet into the processing line being set in motion by a general motor to which the kinematics of the line are connected, the motor of the drive means in rotation is said general motor, which said rotary drive means further comprise, a speed generator having an output, the mechanical clutch systems being capable of being activated to respectively engage the rotary members on the output of the generator speed and to be deactivated to respectively disengage the rotary members with respect to said output, this speed generator being capable, from the input speed communicated by the general motor to the input shaft of the speed generator , generate a speed law comprising a stop phase, a speed-up phase during which the speed at the output of the v generator itesse gradually increases until reaching the speed of the means of transport and introduction, a constant speed drive phase and a phase of reduction of the speed at the output of said generator until it becomes zero, and that the means for controlling the clutch systems and the means for controlling the brake systems are capable of activating or deactivating these systems selectively as a function of the position of the bottom sheet of the stack by relative to the rotary members, this position being identified by identification means.

The device according to the invention makes it possible to abstain from the presence of a vertically mobile support, which makes it possible both to limit the cost of manufacture and to simplify the implementation of the device, since it is no longer necessary to adjust the synchronism of a vertical movement and the rotation of the rotary members.

As will be seen in detail below, the fact of providing, for each rotary member, a mechanical clutch system, makes it possible to successively disengage the rotary members mechanically, as the rear edge of the sheet brought towards the means of transport and introduction exceeds them. In other words, each rotary member continues to contribute to the supply of the sheet until the rear edge of the latter escapes it. Thus, the frictional forces to which the lower sheet is subjected when it is brought to the means of transport and introduction are considerably reduced compared to those which occurred in known devices, since the sheet continues to be entrained by the supply means until its rear edge escapes the most downstream rotary member, while in the prior art using vertically movable supports, it ceased to be driven by the rotary members from that it became necessary to raise the vertically movable support, either when the rear edge of the sheet reached the level of the rotary member located most upstream, or when its front edge reached the level of the means of transport and introduction .

Furthermore, the fact that all the rotary members of the supply means are set in speed by the same speed generator to which each of them is connected by a clutch system, constitutes one embodiment at a time. simple and economical. Indeed, depending on the position of the rear edge of the lower sheet with respect to the rotary members, the clutches are successively disengaged by a simple mechanical action, without it being necessary to suddenly stop the speed generator, which may even temporarily continue turning after disengaging the most downstream rotary member. If it is desired to stop the rotary members, this can be achieved, after disengaging them, by actuating the brake systems which are connected to them. In addition, the provisions of the invention make it simple and economical to ensure the operation of the sheet feeding device. The fact of using the general motor to drive the rotary members represents a substantial saving. In addition, the speed generator plays the role of an intermediary which, from the speed delivered by the general engine, generates a speed law. This arrangement ensures that the rotary members are actuated in synchronism with all of the elements of the kinematics of the line. As will be indicated below, the speed generator can be a simple mechanical system.

The invention therefore makes it possible to perfectly feed the sheets to be treated, without having to use an expensive electronic system which is difficult to repair in the event of a breakdown.

The particular speed law generated by the speed generator is perfectly suitable for actuating the rotary members. In particular, the constant speed drive phase after the acceleration phase constitutes a stable leaf drive period during which the leaves can simultaneously be driven in the line at the same speed by the means of transport and introduction, in the vicinity of their front ends, and by the rotary members (or at least some of them), in their main parts or in the vicinity of their rear ends. This allows on the one hand to "relieve" the means of transport and introduction without requiring them to provide alone a large part of the transport of the leaves and, on the other hand, to avoid damaging leaves by severe pinching or tightness.

Advantageously, the means for controlling the clutch systems are capable of activating the said systems during a phase of stopping the speed law and successively deactivating these systems during a phase of drive to constant speed. Thus, the clutch systems are stressed during the stopping phases, which considerably limits the risks of wear and allows very rapid rotation of the rotary members, which are engaged before the setting phase begins. quickly.

Advantageously, if we consider that a cycle of the speed law corresponds to a rotation of angle α of the generator output, the phases of speeding up and reduction of speed correspond respectively to rotations of angles α 1 and α 3 respecting the following relationships:

0.05 α <α 1 <0.15 α

0.05 α <α 3 <0.15 α while the constant speed drive phase corresponds to an angle rotation α 2 respecting the following relationship:

0.7 α <α 2 <0.9 α

Thus, the acceleration and deceleration phases are brief, while the constant speed drive phase extends over 70 to 90% of a cycle and plays its role of stable period during a part of which the sheets can be simultaneously driven by the means of transport and introduction and by the rotary members.

The invention will be clearly understood and its advantages will appear better on reading the detailed description which follows, of embodiments indicated by way of nonlimiting examples. The description refers to the attached drawings, in which:

FIG. 1 is a diagrammatic side view showing a device according to the invention, FIG. 2 is a partial sectional view along line II - II of FIG. 1,

FIG. 3 is a partial vertical sectional view along the line III - III of FIG. 1,

FIGS. 4a to 4f illustrate different stages of feeding the sheets in the processing line,

FIGS. 5 and 6 are diagrams showing the speed laws for two operating possibilities,

- Figure 7 is a view similar to Figure 1, showing a variant, - Figure 8 is a view similar to Figure 3, showing a variant of the rotary drive means of the rotary members,

FIG. 9 is a partial section along the line IX-IX in FIG. 8,

FIG. 10 is a diagram illustrating a configuration of the main elements of a speed generator adapted to the invention and, - Figure 11 shows schematically the development of the groove of the cam constituting one of these elements.

The feed device 1 of FIG. 1 is a feeder module for a sheet processing line. These sheets are introduced in the direction of arrow f in the various modules of the line, starting with module 2 which is arranged downstream of module 1 and attached to the latter, and which constitutes for example a printer module (partially shown ).

The device 1 comprises a receiving location 10 for a stack of sheets 12 and has a cover la, which is only shown diagrammatically to show the external shape of this device. In its downstream part, considered in the direction f for transporting the sheets, it comprises means for transporting and introducing sheets into the processing line, that is to say, first of all, in module 2 In the variant of FIG. 1, these means of transport and introduction comprise two rotary rollers 14 and 16 located one above the other and rotating in opposite directions. These rollers delimit between them a space capable of allowing the insertion of a sheet and its nipping between the two rollers, the respective directions of rotation being determined so that a sheet introduced into this space is advanced in the direction of the arrow f.

In order to select the lower sheet 12a from the stack of sheets 12, and bring it to the means of transport and introduction, the device comprises supply means 18.

These supply means comprise rotary members placed one after the other in the direction f of transport of the sheets, upstream of the transport and introduction means. In the example shown, three rotary members 20, 22 and 24 are provided, the first rotary member 20 being located furthest upstream, while the third, 24, is located furthest downstream. Note that one could have only two rotary members but, for example depending on the length of the sheets to be treated, provide four or more.

These rotary members are arranged in a suction box 26 which is located under the location 10 for receiving the stack of sheets. As seen in Figure 1, the rotary members 20, 22 and 24 come into contact with the underside of the lower sheet 12a of the stack of sheets. The rotary members 20, 22 and 24 each rotate around an axis (respectively a1, a2, a3) perpendicular to the direction of transport of the sheets, in a direction of rotation indicated by the arrows r, which is the same as that of the lower roller 16 of the means of transport and introduction.

The suction box 26 is connected to a lower pipe 28, in which a vacuum is generated, which tends to draw the air downward in the direction of the arrows T in FIG. 1, to press the lower sheet against the rotary members 20, 22 and 24. This box has a bottom wall 26a in which the pipe 28 opens, and side walls.

The device also includes a thickness gauge 30 which is placed at the front of the stack of sheets. This gauge is adjusted so that the vertical distance between its lower edge 32 and the rotary members 20, 22 and 24 is slightly greater than the thickness of a sheet, so that when the bottom sheet 12a is drawn into the direction of arrow f, the front edges of all the other sheets of the stack cooperate in abutment with the rear face 34 of the gauge 30 to prevent these sheets from being driven in the direction of arrow f.

The rotary members 20, 22 and 24 protrude beyond the upper end 27 of the suction box 26, substantially up to the lower level NI of the location 10 for the stack of sheets. This level being occupied by the lower sheet 12a, the rotary members always come into contact with this sheet.

In fact, in the example shown, the rotary members 20, 22 and 24 even constitute support means for the sheet stack 12. More precisely, this sheet stack is supported, in its front part, by the rotary members and , in its rear part, by a rear support member 36, placed on a plate 36 '.

In this case where the rotary members constitute support means, it is they which define the level NI for the front part of the stack of sheets. In the event that an additional support element is provided in the same region, it would define the NI level and should have slots allowing the rotary members to protrude slightly beyond this NI level.

It can therefore be said that the rotary members extend at least up to the NI level. The rotary members are rotated by drive means, shown partially in Figure 1 and better visible in the sections of Figures 2 and 3. These rotation drive means comprise a speed generator 40 having an output constituted by an output shaft 42. The rotation drive means also comprise, for each rotary member 20, 22 and 24, a mechanical clutch system, respectively 50, 52 and 54. Each clutch system is capable of being activated to engage the rotary member associated with it on the output 42 of the speed generator and to be deactivated to disengage this rotary member relative to the output shaft 42. In addition, a brake system, respectively 60, 62 and 64 is associated with each rotary member 20, 22 and 24 and is capable of being activated to brake the rotary member with which it is associated and of being deactivated to release this rotary member.

The clutch systems and the brake systems are implemented by control means which act as a function of the position of the lower sheet 12a with respect to the rotary members during its supply to the means of transport and introduction. . To simplify, we have only shown diagrammatically the control means 66 which control the clutch 50 associated with the first rotary member 20 and the control means 68 which control the brake system 60 associated with the same rotary member. These means are for example electrical, pneumatic or electromechanical. The position of the sheet is marked by marking means 70.

These locating means have been shown very schematically. They can be made mechanically and be constituted by an encoder driven in rotation during the advancement of the sheet and thus capable of counting the length over which the sheet has advanced, which allows, the total length of the sheet being known, to know the position of the rear edge of the sheet relative to the rotary members. This encoder can be directly connected to the control means of the clutch and brake systems to activate or deactivate them according to its angular position or the number of rotations performed. It is also possible to use other marking means such as position sensors distributed over the path of advancement of the sheet or arranged near the rotary members. When the locating means detect a position of the sheet which, for example, requires the deactivation of a clutch system or the activation of a brake system, the control means of this system automatically performs the necessary operation . The transmission between the locating means and the control means can be done mechanically, electrically, pneumatically or electronically.

To be able to advance the lower sheet 12a during rotation in the direction of the arrows r, the rotary members must have contact parts, in contact with the lower sheet, generating frictional forces with the latter. These contact parts can therefore be surfaces with relatively strong adhesion, and may for example be made of rubber, rough material or the like.

As best seen in Figure 2, in the example shown, the rotary member 20 comprises a shaft 72, arranged perpendicular to the direction of transport of the sheets, and a plurality of rollers 75, the surface of which is capable of generating friction forces with the leaves, regularly distributed on this shaft and integral in rotation with the latter. It is these rollers 75 which protrude beyond the upper end of the suction box to come into direct contact with the underside of the bottom sheet of the stack. The other rotary members are similar.

The shafts 72, 74 and 76 of the rotary members 20, 22 and 24 are receiving shafts which can be driven in rotation when the respective clutch systems of these rotary members are activated.

For each rotary member, the drive means comprise an intermediate shaft, respectively 80, 82 and 84, connected, on the one hand to the outlet 42 of the speed generator 40 and, on the other hand, to the clutch system, respectively 50, 52 and 54, of the rotary member, respectively 20, 22 and 24. The intermediate shafts 80, 82 and 84 are therefore rotated by the outlet 42 of the generator 40 and the clutches make it possible to secure the receiving shafts in rotation with these intermediate shafts. The transmission from the intermediate shafts to the receiving shafts is therefore carried out directly by the clutch systems, while the transmission between the speed generator and the intermediate shafts is carried out by first transmission means. The clutch systems are shown schematically in the figures. They can be constituted by clutch clutches, by friction clutches or others.

The first means of transmission are now described. The output shaft 42 of the speed generator 40 supports an output pulley 43 which, by means of a belt 44, rotates a pulley 45, itself mounted on a shaft 46. This shaft has grooves or is integral with a pinion 47.

The intermediate shafts 80, 82 and 84 are themselves integral with receiving pinions, respectively 81, 83 and 85. The transmitting pinion 47 meshes with the receiving pinions 83 and 85 to rotate the intermediate shafts 82 and 84. The intermediate shaft 80 is driven in rotation by means of an intermediate pinion 48 which meshes with the pinions 81 and 83. The intermediate shafts are therefore all integral in rotation, and the receiving shafts of the rotary members can be driven in rotation or not, depending on whether their respective clutch systems are activated or deactivated.

The speed generator 40 is connected to the overall kinematics of the processing line. More specifically, the transport and introduction means 14 and 16 described above are set in motion by a motor (not shown) to which the general kinematics of the line are connected. The speed generator 40 comprises an input shaft 39 on which a pulley 37 is mounted. A belt 35 can connect this pulley to another pulley (driving pulley 33) of the overall kinematics of the line to drive the shaft 39 in rotation by the general motor of the line. From the input speed communicated by the input shaft 39, the speed generator generates, at its output 42, a speed law which will be specified later, with reference to FIGS. 4a to 4f.

As seen in FIGS. 2 and 3, the braking systems 60, 62 and 64 of the rotary members 20, 22 and 24 cooperate directly with the receiving shafts 72, 74 and 76 of these rotary members. These may be friction brake systems or the like.

As indicated in FIG. 3, a fan 90 generates the vacuum in the lower pipe 28 of the suction box 26. In its upper part, this pipe 28 opens, on the lower wall 26a of the box 26, to open under rotary organs. The upper end 27 of the box 26 can be open or, as in the example shown, be provided with a wall element 29 provided with slots 29 ′ through which the rollers 75 of the rotary members protrude. The main thing is that the suction generated by the fan 90 applies, possibly through these slots, to the lower sheet 12a and presses the latter on the rollers 75.

Depending on the conditions of use, or the type of sheets treated by the treatment line, you may wish to adjust the suction surface. To do this, the upper part of the suction box is provided with interior division walls 92. These division walls 92 are provided with openings 94 through which the air circulates as indicated by the arrows g. As best seen in Figure 2, the size of the openings 94 can be adjusted using flaps 96 controlled by control rods 98. By actuating the rods 98, the flaps 96 are moved so that they cover more or less the openings 94, which makes it possible to increase or decrease the suction surface as a function of the dimensions of the sheet to be driven.

With reference to FIGS. 4a to 4f, the feeding cycle of the sheets in the processing line will now be described.

FIG. 4a shows the device loaded with a sheet stack in a stopping phase, which corresponds to the situation represented in FIG. 1. For simplicity, only the elements which make it possible to understand the cycle are represented in a schematic manner.

In this stopping phase, the kinematics of the line is on, so that the rollers 14 and 16 rotate at constant speed, but the output of the speed generator 40 is stopped and does not drive the rotary members 20, 22 and 24, so that the bottom sheet 12a of the stack of sheets is stopped. Note, however, that, as indicated above, this sheet rests on the rotary members 20, 22 and 24 as well as on the rear support element 36. FIG. 4b shows the introduction phase, in which the members rotary 20, 22 and 24 are set in speed and accelerated by the generator 40 until reaching the same speed as the means of transport and introduction. On this occasion, the rollers of the rotary members cooperate with the underside of the lower sheet 12a, and the latter is brought to the means of transport and introduction. Thanks to the presence of the thickness gauge 30, the other sheets of the stack are not entrained.

In FIG. 4c, the rotary members 20, 22 and 24 rotate at constant speed (the same as that of the means of transport and introduction) and the lower sheet 12a cooperates with the means of transport and introduction. It can be seen in this figure that the rear edge 13 of the lower sheet 12a has not yet completely reached the first rotary member 20.

On the other hand, in FIG. 4d, the rotary member 20 is uncovered by the sheet 12a (in other words, the rear edge 13 of this sheet has exceeded this rotary member) and, the locating means having detected this situation, this first rotary member 20 is disengaged and braked (its clutch system has been deactivated while its braking system has been activated) and it does not tend to move the sheet 12b of the stack which is now in contact with it. On the other hand, the other rotary members 22 and 24 remain engaged and continue to drive the lower sheet 12a in the direction of its transport. It should be noted that, depending on the response times of the clutch systems, the clutch can be controlled slightly before the rear edge 13 of the sheet 12a reaches the level of the rotary member 20. In FIG. 4e, it is the second rotary member 22 which has been uncovered by the lower sheet 12a, and has been disengaged and braked to avoid stressing the movement of the other sheets of the stack. The third rotary member 24 continues to rotate and drive the bottom sheet 12a. In FIG. 4f, this third rotary member has in turn been discovered, disengaged and braked. The sheet 12a is no longer driven except by the means of transport and introduction.

Thanks to the description of Figures 4a to 4f which has just been made, it is understood that the rotary members continue to drive the sheet 12a until they are discovered by the latter. Consequently, this sheet 12a, until it discovers the downstream rotary member 24, is either only driven by the three rotary members, or is driven both by at least some of these rotary members and by the means of transport. and introduction. The only friction forces which are exerted on the sheet 12a and tend to oppose its transport are those which are due to the sheet 12b located immediately above in the stack. These forces of friction is very low as long as the rotary members rotate or can rotate, and become more significant only when even the downstream rotary member has been disengaged, that is to say for a very short period of time and over a very small sheet surface 12a. It is therefore not necessary to pull strongly on the sheet or to pinch it strongly to transport it correctly.

In FIG. 5, the quantity V indicated on the ordinate is the output speed of the speed generator 40, and the quantity d indicated on the abscissa is the distance traveled by a sheet advancing in the processing line. The PI reference corresponds to one step of the processing line. It is the distance which corresponds to a complete cycle of the main module of the line, this main module being the one which determines the speed of advance in the line. In other words, the step is the nominal developed of the line. In general, when the line comprises a plate cylinder, it is the development of this cylinder which determines the pitch of the line.

At point A indicated on the abscissa, the speed generator 40 is stopped.

Point O corresponds to the situation in FIG. 4a, in which the output of the speed generator 40 is stopped, but in which the rotary members are ready to be put into speed by this speed generator, the clutch systems are by therefore activated while the brake systems are deactivated. It is from this point O that the speed setting begins.

The segment OB corresponds to FIG. 4b, it is the phase of speeding up of the sheet during which the speed at the output of the speed generator progressively increases until reaching the speed VI of the means of transport and introduction. .

The segment BC corresponds substantially to FIG. 4c, since the sheet is driven at constant speed over this segment. Point C shows the precise place where, the rear edge of the sheet having discovered the upstream rotary member, the latter is disengaged while its brake is activated. The disengagement and the activation of the brake are linked to the position marked by the marking means. The length of the segment BC is therefore adjustable as a function of the length of the sheet. The points D and E correspond respectively to FIGS. 4e and 4f, that is to say at the moment when the rotary members 22 and 24 are respectively discovered and, consequently, disengaged and braked.

In the EF segment, the sheet left the means of supply, and was taken care of by the means of transport and introduction. The output speed of the speed generator therefore gradually decreases to become zero at point F. It is at this point that, the speed being zero, the rotary members can again be engaged while their brakes are deactivated in order to start a new cycle. The end of the constant speed training phase is marked by point El, located between points E and F.

FIG. 6 shows a variant, used when the length of the sheet introduced into the processing line is greater than the pitch of this line. In this figure, the quantities indicated respectively on the abscissa and on the ordinate are the same as in FIG. 5. The speed law of the speed generator is the same as for FIG. 5; it increases gradually, remains constant over a determined length, and goes to 0 when the advancement length is equal to the pitch of the machine. The cycle for feeding the sheet into the processing line is longer than that which has been described previously with reference to FIG. 5, and extends over a length greater than the pitch of the machine. The bringing of a sheet and its processing in the line will therefore be done on two turns of the main element of the line, the second turn being partially used.

Points A ', O' and B 'correspond to points A, O and B in Figure 5. On segment B'C, the sheet is driven at a constant speed equal to the speed VI of the line.

Insofar as the output speed of the speed generator becomes zero at point P'1, which marks a step of the machine, it is necessary to disengage the various rotary members to prevent them from hindering the advancement of the sheet . However, it is important not to slow them down at the same time. Thus, points C, D 'and E' mark the distances at which the three rotary members 20, 22 and 24 are successively disengaged. These distances can be predetermined, so that the tracking means do not transmit any information on this occasion. At distances C, D 'and E', the clutch systems are therefore deactivated, but the braking systems remain inactive. Points C, D 'and E' can be practically confused and correspond to the point El (FIG. 5) which marks the end of the training phase at constant speed.

Note that when reaching point P'1, the front edge of the sheet can already be introduced into the means of transport and introduction into the line, so that even if the output speed of the speed generator is zero, the speed of advancement of the sheet is not zero. It is for this reason that it is essential that the rotary members be disengaged without opposing the advancement of the sheet.

On the other hand, the point G marks the step from which the upstream rotary member is discovered by the rear edge of the sheet. This is detected by the locating means, and the means for controlling the braking system of the upstream rotary member are activated in order, only at this moment, to effectively brake this upstream rotary member. During the entire distance between points C and G, this rotary member therefore remained disengaged but not braked. The distance O'G is adjustable according to the length of the sheet.

Points H and I correspond to point G, respectively for the second and third rotary members.

Of course, if the length of the sheets is such that after one step of the processing line, a relatively large sheet length is still in the region of the rotary members, it may be useful to use the latter again for leaf pick-up after the end of the new speed-up phase. Thus, in the case of FIG. 6, the clutch systems of the rotary members 22 and 24 could be reactivated. The points H and I would then correspond to the disengagement and to the braking of these members.

After point I, no rotary member no longer cooperates with the bottom sheet. However, since a new line cycle has started from point P'1, the output speed of the speed generator continues its conventional speed cycle until it becomes zero at point F. It is only from point P2, corresponding to twice the machine pitch that a new cycle for introducing a new sheet can begin.

In FIGS. 5 and 6, that is to say both when the length of the sheets is less than the pitch of the treatment line and when it is greater, the clutch systems are activated during a stop phase (AO and A'O) and, at least for the first time, deactivated during a constant speed training phase (CDE or CD 'E'). In FIG. 5, this deactivation coincides with the activation of the respective braking systems, while in FIG. 6, the braking systems are not activated until later. The lengths of the speed-up (OB) or deceleration (El F) phases are advantageously between 5% and 15% of the pitch, while the length of the drive phase at constant speed is of the order of 70 % to 90% of the step.

Referring to Figure 7, we now describe an alternative embodiment of the means of transport and introduction. This variant is made possible thanks to the fact that the invention makes it possible to considerably reduce the friction forces and therefore no longer makes it necessary to pinch strongly on the driven sheet.

The means of transport and introduction shown in FIG. 7 comprise a downstream suction box 96, similar to the suction box 26 and at least one downstream rotary member, disposed in the downstream box 96 and protruding beyond the 'upper end 97 of the latter. This rotary member comes into contact with the transported sheet to drive it in the direction of transport indicated by the arrow f. In the example shown, three downstream rotary members, 100, 102 and 104, similar to the rotary members 20, 22 and 24 of the supply means, are provided. They can be rotated by gear systems such as those previously described for the supply means, mounted on shafts connected to the overall kinematics of the line (this connector is not shown). Insofar as only one sheet is in contact with the downstream rotary members, it may be necessary to provide a system for limiting the air flow rates sucked in by the downstream suction box 96. To do this, a cover member 106 opposite the upper end 97 of the downstream suction box, a space capable of receiving a sheet being formed between this cover member and the downstream rotary member or members arranged in the downstream box.

In Figure 7, the downstream rotary members cooperate with the underside of the sheet which is driven by the means of transport and introduction. In fact, the downstream suction box draws this sheet down and thus forces it to rest on the downstream rotary members. Alternatively, provision could be made to place a downstream suction box over the path leaves. The entrained sheet would then be drawn upwards and this time would be its upper face which would cooperate with the downstream rotary members.

It should also be noted that it is possible to produce the rotary members using one or more endless belts driven by pulleys. These belts can be used in the downstream suction boxes of the variants mentioned above. It is also possible to use such belts to replace the rollers 14 and 16 of FIG. 1, by placing them so that they delimit between them a space suitable for allowing the insertion of a sheet and its nipping between the belts. In FIGS. 8 and 9, which show a variant of the means for driving the rotary members in rotation, the elements similar to those of FIGS. 2 and 3 are designated by the same references, increased by 100.

In this variant also, the means for rotating the rotary members comprise, for each rotary member, an intermediate shaft connected to the output of the speed generator and to the clutch system of the rotary member, as well as a shaft receiver secured to the rotary member. However, in this variant, the clutch and brake systems are directly placed on the intermediate shafts. Thanks to these arrangements, the clutch and brake systems act directly on the intermediate shafts and are very close to one another (they can even be physically combined into one and the same clutch and brake member).

More specifically, the means for driving the shafts 172, 174 and 176 in rotation of each of the rotary members comprise an intermediate shaft, respectively 180, 182 and 184, driven in rotation by the output 142 of the speed generator 140. For each member rotary, clutch and brake systems are mounted on the intermediate shaft. FIG. 8 thus shows the clutch 152 and brake 162 systems mounted on the intermediate shaft 182 of the rotary member 122. To allow braking of the rotary member even when it is disengaged, the brake system is located between the clutch system and the output of the intermediate shaft. This intermediate shaft may comprise two sections capable of being joined in rotation by the clutch system, in which case the brake system is placed on the second section (that is to say on the outlet section). In this variant, first transmission means connect the speed generator to the intermediate shafts and second transmission means connect the intermediate shafts to the receiving shafts.

The first means of transmission are now described. As shown in the schematic partial section of FIG. 9, the intermediate shafts 180, 182 and 184 are rotated by the same belt 144 cooperating with the output pulley 143 of the speed generator 140. Each intermediate shaft has a pulley d 'Input such as the pulley 182' of the shaft 182. The belt 144 passes over the pulley 143 and on each of the input pulleys of the intermediate shafts. To adjust the tension of this belt and force it to cooperate on a relatively large part of the input pulleys of the intermediate shafts, idlers 191 and 191 ', movable in a plane perpendicular to the intermediate shafts can be located between each pair of two successive intermediate shaft input pulleys.

We will now describe the second transmission means, which also include a belt and pulley system.

Each of the intermediate shafts 180, 182 and 184 has an output pulley, respectively 180 ", 182" and 184 ". Each of the receiving shafts, respectively 172, 174 and 176, (shafts on which the rotary members are mounted) has a pulley 172 ', 174' and 176 'respectively. Transmission belts between the intermediate shafts and the receiving shafts of the rotary members, respectively designated by the references 172 ", 174" and 176 ", respectively connect the pulleys 172' and 180 ", the pulleys 174 'and 182", and the pulleys 176' and 184 ". The tension of these transmission belts can be adjusted using idler wheels and cooperating with them.

Preferably, the input pulleys of the receiving shafts are located in the middle regions of these shafts, which makes it possible to avoid possible problems of torsion of the shafts.

The belts are advantageously notched belts. The use of such a belt and pulley system, unlike gears, avoids the presence of oil.

FIGS. 10 and 11 will now be described, which illustrate the constitution of the main elements of a speed generator capable of generating a speed law of the type of that of FIGS. 5 and 6. Thus, FIG. 10 shows in elevation, partially and schematically, a cam member 200 connected to the input shaft of the speed generator and driven in rotation in the direction RI around an axis 202. This axis 202 can be a section of the speed generator input shaft 39 or a shaft connected to the shaft 39 so as to be provided with a constant speed of rotation. In any case, the shaft 202 rotates at the same speed as the output shaft of the general motor of the line and is connected to the latter by any known means of transmission. This member 200 is produced in the form of a cylinder, the axial face of which is provided with a generally helical groove 210. The speed generator also comprises a cam follower member 220 produced in the form of a disc able to rotate about an axis 222 perpendicular to the axis 202.

The disc 220 is provided with radial rollers 224a, 224B ..., projecting radially and possibly free to rotate around radial axes 225a, 225b ...,

These rollers are regularly distributed around the periphery of the disc 220 and are able to engage in the groove 210. Due to the rotation of the member 200 in the RI direction, they make it possible to drive the disc 220 in rotation in the meaning R2. As a result, the output shaft 42 of the speed generator is rotated at a speed proportional to that of the axis 222 which is integral in rotation with the disc 220.

The shaft 42 can be constituted by a terminal section of the axis 220, in which case its speed is obviously the same as that of this axis. However, in the example shown, the length of the groove 210 and the number of rollers are such that a complete rotation of the member 200 only drives the disc 220 over a portion of a tower. It may therefore be necessary for the shaft 42 to be connected to the axis 222 by means of a revolution multiplier such as a system with toothed wheels or with belts and pulleys of different sizes. As best seen in Figure 11 which shows the appearance of its development, the groove 210 has a particular configuration. It has in fact the shape of a helical curve whose angle, relative to a plane P perpendicular to the axis 202, is variable. For the sake of clarity, this fictitious plane P is indicated in several places in FIGS. 10 and 11. Thus, on a first section extending between the points hl and h2, the angle of the groove relative to the plane P is zero. Therefore, when T)

roller is engaged in this section, the rotation of the member 200 leaves the disc

220 still. This section therefore defines the stop phase of the speed law.

On a second section of the groove extending between the points h2 and h3, the angle βl with respect to the plane P increases continuously until a given value β2. When a roller is in this section, the speed of rotation of the disc 220 increases as this roller approaches point h3. This section corresponds to the speed-up phase.

On the third section, extending between points h3 and h4, the angle β2 of the groove relative to the plane P remains constant. Therefore, when a roller is in this section, the speed of the disc 220 and its axis 222 is constant. The speed of the output 42 of the speed generator is constant and stabilized at VI. This section corresponds to the constant speed training phase.

Finally, on the fourth section, between the points h4 and h5, the angle β3 with respect to the plane P decreases continuously from the value β2 until it becomes zero. This section corresponds to the deceleration phase. In fact, on the groove 210, the point h5 corresponds to the point hl.

The example in FIG. 10 shows the section h3, h4 in a middle region of the member 200. When a roller enters the groove, it is preferable for it to attack it with a non-zero but relatively small angle.

Thus, in FIG. 10, the rollers attack and leave the groove in a part of the section h4, h5 (they could also do so in a part of the section h2, h3). This section extends partly in the vicinity of each of the axial ends of the member 200. The section h3, h4 is considerably longer than the other sections to ensure that the drive phase at constant speed allows routing the leaves over a distance of between 70% and 90% of the pitch of the treatment line.

Claims

1. Device for feeding sheets into a line for processing these sheets, the device comprising a location (10) for receiving a stack of sheets (12), means of transport and introduction (14, 16) d '' a sheet in the processing line and supply means (18) from the bottom sheet of the stack to said transport and introduction means, these supply means comprising at least first and second members rotary (20, 22, 24) placed, one after the other in the direction (f) of transporting the sheets, upstream of the means of transport and introduction (14, 16), arranged in a box of suction (26) located under the receiving location and capable of coming into contact with the bottom sheet (12a) of the stack, the device further comprising means for driving each rotary member in rotation around an axis perpendicular to the direction of transport, device in which the location (10) for the a stack of sheets having a given lower level (NI) capable of being occupied by the lower sheet of the stack, the rotary members protrude beyond the upper end (27) of the suction box (26), substantially up to this lower level, and are permanently capable of coming into contact with the lower sheet (12a) of the stack, in which the means for driving the rotary members in rotation comprise a motor and, for each rotary member ( 20, 22, 24), a mechanical clutch system (50, 52, 54) capable of being activated to engage the rotary member and of being deactivated to disengage said rotary member, as well as a brake system ( 60, 62, 64) capable of being activated to brake the rotary member and of being deactivated to release said member, the rotary drive means further comprising means for controlling the clutch systems (66 ) and means for controlling the brake systems (68 ), characterized in that, the means of transport and introduction

(14, 16) of a sheet in the processing line being set in motion by a general motor to which the kinematics of the line is connected, the motor of the rotary drive means is said general motor, in that said means rotational drive further comprises a speed generator (40) having an output (42), the mechanical clutch systems (50, 52, 54) being capable of being activated to engage the clutch respectively the rotary members on the output (42) of the speed generator and to be deactivated to respectively disengage the rotary members with respect to said output, this speed generator being capable, from the input speed communicated by the motor general to the input shaft (39) of the speed generator, to generate a speed law comprising a stop phase (AO, A'O), a speed up phase (OB, OB ') during of which the speed at the output of the speed generator (40) gradually increases until reaching the speed (VI) of the means of transport and introduction (14, 16), a drive phase at constant speed (BCDE, B 'C'D'E') and a phase (EFPl, E'P'l) of reducing the speed at the output of said generator until it becomes zero, and in that the control means of the systems d clutch (66) and the brake system control means (68) are capable of activating or deactivating selectively ver these systems as a function of the position of the bottom sheet (12a) of the stack with respect to the rotary members (20, 22, 24), this position being marked by marking means.

2. Device according to claim 1, characterized in that the means for controlling the clutch systems (66) are capable of activating said systems during a stopping phase (AO, A'O) of the law speed and successively deactivate these systems during a constant speed drive phase (BCDE, B'C'D'E ').

3. Device according to claim 1 or 2, characterized in that the means for driving the rotary members in rotation (20, 22, 24) comprise, for each rotary member, an intermediate shaft (80, 82, 84; 180, 182, 184) connected, on the one hand, to the output (42; 142) of the speed generator (40; 140) by first transmission means and, on the other hand, to the clutch system (50, 52 , 54; 152) of the rotary member, as well as a receiving shaft (72, 74, 76; 172, 174, 176), integral with the rotary member (20, 22, 24) and capable of being driven in rotation by the intermediate shaft when the clutch system of the rotary member is activated.

4. Device according to claim 3, characterized in that the clutch and brake systems (152, 162) are directly placed on the intermediate shafts (180, 182, 184) and in that second transmission means (180 ", 172 ', 172"; 182 ", 174', 174"; 184 ", 176 ', 176") connect the intermediate trees to the receiving trees (172, 174, 176). 23

5. Device according to claim 4, characterized in that the transmission means comprise a belt and pulley system (180 ", 172 ^* , 172"; 182 ", 174 ', 174"; 184 ", 176', 176" ).

6. Device according to claim 3, characterized in that, for each rotary member (20, 22, 24), the braking system (60, 62, 64) is capable of cooperating with the receiving shaft (72, 74, 76) integral with said member and the clutch system (50, 52, 54) is capable of connecting the intermediate shaft (80, 82, 84) to the receiving shaft.

7. Device according to any one of claims 1 to 6, characterized in that the rotary members (20, 22, 24) constitute support means for the stack of sheets (12).

8. Device according to any one of claims 1 to 7, characterized in that the means for transporting and introducing a sheet into the processing line comprise two rotary rollers (14, 16), one located at above the other and rotating in opposite directions, these rollers delimiting between them a space (17) capable of allowing the insertion of a sheet and its nipping between the two rollers.

9. Device according to any one of claims 1 to 8, characterized in that the means for transporting and introducing a sheet into the processing line comprise a downstream suction box (96) and at least one member downstream rotary (100, 102, 104), disposed in the downstream box (96), projecting beyond the upper end (97) of the latter and capable of coming into contact with a sheet leaving the supply means .

10. Device according to claim 9, characterized in that it comprises a cover member (106) disposed opposite the upper end (97) of the downstream suction box, a space capable of receiving a sheet being formed between said cover member and at least the downstream rotary member disposed in the downstream box.