FR2491895A1 - METHOD AND DEVICE FOR PLANETARY SYNCHRONIZATION, IN PARTICULAR FOR CONVEYORS OF PRINTING PRESSES - Google Patents

Abstract

IN THIS PLANETARY SYNCHRONIZATION SYSTEM, THE LENGTH OF AN ENDLESS BELT CONVEYOR 16 RUNNING ON A DRIVE WHEEL 12 AND A RETURN WHEEL 14 IS ADJUSTED TO KEEP THE LENGTH OF THE CONVEYOR EQUAL TO A MULTIPLE OF THE CIRCUMFERENCE OF THE WHEEL DRIVE 12, WHICH CAN BE DRIVEN AT A VARIABLE SPEED, WHEN THE DIAMETER OF THE DRIVE WHEEL VARIES. THE LENGTH ADJUSTMENT CAN BE CARRIED OUT WITH A SCREW-NUT SYSTEM 55, 60. APPLICATION IN PARTICULAR TO PRESSES TO BE PRINTED BY SHEETS.

Description

The present invention relates to a planetary synchronization system

  intended to be used in conjunction with conveyor systems of the type described in the US Dahlgren patent, having NO. 3,644,261, under the title

  "Direct Feed Press" and in the patent pending

  in the United States of America on behalf of Dahlgreen, having No. 3,847,079, under the heading "Sheet printing process". The above-mentioned patents relate to a sheet-fed printing press which implements a principle of direct and continuous transfer of the sheets, similar to the type of feed of a belt-fed printing press, and according to which the sheets are seized by pinch or seizure bars carried by steel tapes or flexible bands which pass over drive wheels to drive the sheets through a plurality of printing stations. When printing, it is crucial that the framing or the synchronization of the sheet on each printing roll is maintained in a precise manner.

  in such a way that the points on each sheet cor-

  respond precisely to a corresponding point on the other sheets. In the case of monochrome printing, it is also essential that the framing or synchronization is maintained since the sheets often pass through a printing press more than once, to allow the application of colors.

additional.

  In the conveyor system described in the patents cited above, the flexible steel strips were

  driven by circular wheels mounted in the vicinity

  swimming opposite ends of the printing press

  on these ribbons were indexing pins.

  This resulted in two main problems that tended

  to alter the commercial value of the system.

  In the first place, the expansion of different materials depends on the temperature, although, for calculation purposes,

  constant average values. If the lengths, the

  faces and volumes are at a normal temperature

  the approximate variation in the dimensions of the material

  riau will be considered as a function of the variation in temperature. At best, such a criterion

  design or calculation only provides dimensions.

  approach and a resulting inaccuracy in the speed and position of the parts of the system. Even if all the components of the printing press can

  be made of materials with coefficients of

  identical factors of thermal expansion, the dimensions

  different components of the system may vary non-uniformly, resulting in

  additional variation in speed and posi-

  different parts of the system, which is

  at the expense of alignment or framing on the foot.

  Secondly, even if we neglect the dila-

  it is practically impossible to con-

  trimming circular organs and performing a training

  with them to maintain a framing or

  absolute alignment. The Greek letter w, pronounced "pi".

  is the ratio of the circumference of a circle to its diameter and the number by which the diameter of the circle must be multiplied to obtain the circumference. Therefore the circumference of a circle is equal to w

times the diameter of the circle.

  The number X can not be exactly expressed as a decimal digit. The usual values used to express e include 22 divided by 7, and the figures 3,14, 3,1416, and 3,14159. Taking a value rounded to the twentieth decimal,

  T is approximately equal to 3.14159265358979323846.

  Therefore, there is a technical problem in obtaining absolute precision in the manufacture of circular members and in maintaining an almost absolute precision of the components and

  the location of parts of a system under conditions

  variable temperature, speed and acceleration

  ration and other operating conditions.

  Various devices have been developed for this purpose to adjust the tension of a continuous strip as well as the distance traveled by a continuous strip.

  between neighboring printing rolls, in order to

  hold the framing or synchronization in band-fed printing presses. However, such devices can not easily be adapted to sheet-fed printing presses of the type described in the aforementioned patents, since the web is generally routed along a sinuous path to compensate for errors.

framing between colors.

  The method and apparatus according to the invention

  described here relate to a conveyor system

  and a global synchronization system.

  intended to provide a framing or alignment

  be an endless surface of a conveyor and a printing cylinder. The method of maintaining endless surfaces of two members, such as a printing roll and an endless belt conveyor driven by a drive wheel associated with the impression cylinder in a precise timing relationship when the wheel drive and conveyor roll over one another, requires the ratio of the speed of the belt conveyor to the length of the conveyor

  be maintained equal to the ratio of the

  of the training wheel at the circumference of

  this wheel, or to a multiple of this report.

  This relationship can be maintained in two ways, even though the dimensions and surface velocities of both the drive wheel and the belt conveyor can vary under the effect of thermal expansion under normal operating conditions. Firstly, the printing roller and the drive wheel of the belt conveyor can be connected together in a driving connection by means of a

  device allowing a super-speed adjustment

  of the impression cylinder compared to the

  superficial speed of the driving wheel of the con-

  striped voyeur so as to restore the ratio between the required speed and the distance, if there is a variation of the speed or dimensions, or both of these elements, either for the driving wheel,

for the conveyor belt.

  In the second place, we can regulate either the circumference

  the drive wheel of the conveyor, ie the length. conveyor belt, one with respect to

  the other, to restore the required ratio between the

himself and the distance.

  It should be noted that, in the case where this seems to be

  tagged, it is possible to adjust in a way that

  to be controlled, ie the ratio of the speeds of the

  the impression and the drive wheel, the

  distance traveled by the training wheel.

  and by the Webmaster, so as to maintain

  a controlled, unsynchronized relationship between the

  printing water and conveyor belt. For example

  it is desirable to advance the sheet on

  a specified distance from the printing roll

  during each revolution of the latter, this

  condition can be established and maintained.

  The preferred embodiment of the system

  planetary described here comprises two epicyclic members!

  endless wheels, such as for example a conveyor drive wheel associated with a printing roller and a conveyor belt, the conveyor drive wheel constituting a circle which rolls on the inside or on the outside the circumference of the conveyor belt. As will be explained in more detail below, the conveyor belt may be circular or, since it is an endless member, it may be arranged in a path other than a circle, in a closed loop. In any case, the

  ratio between speed and distance, indicated below

  above, is maintained by adjusting either speeds relative to

  respective organs, either lengths or cir-

  related conferences of these bodies.

  When adjusting the lengths or circumferences

  ferences of the respective organs, it should be noted that at least one of the members may have a geometry that is variable

  in a controllable and adjustable manner.

  The planetary system is here described in combination

  with a belt conveyor similar to that

  written in patents filed in the United States of America

  * than and mentioned previously. When included in this system, an infinitely variable speed drive member is mounted in the drive system to drive the conveyor drive wheel, so as to allow adjustment of the speed of the conveyor. rotating the drive wheel to correct any variation in the circumference of the drive wheel due to thermal expansion or contraction. If the angular velocity of the drive wheel remains unchanged while the diameter of this wheel is slightly increased as a result of thermal expansion, the superficial velocity of the

  conveyor driven by the drive wheel

  would result in inaccuracy of the arrival of the sheet at the printing roll, which would result in the sheet not being aligned or synchronized with the roll

  printing. However, if we adjust the angular velocity

  re of the drive wheel so as to take into account a variation in the diameter of this drive wheel,

  the moment of arrival of the sheet on the roll of

  As a variant, the angular velocity of the drive wheel can not be modified with respect to the angular velocity of the drive wheel.

  printing roller if you adjust the length of the

  voyeur to adjust the distance traveled by a grab bar or pinch carrying a sheet

  during a complete revolution of the conveyor.

  A main object of the present invention is to provide a planetary system in which epicyclic members are maintained in an alignment relationship even if the circumference of one of the

  organs varies under normal operating conditions.

  by adjusting the speed ratio

geometric sions of the organs.

  Another object of the present invention is to

  provide a conveyor for a food printing press

  by leaves, in which the length of the convo

  It may be adjusted to align or synchronize the conveyor with the printing rollers so as to provide a sheet-fed printing press in which the sheet is continuously gripped by a single set of gripping members. from the moment it enters the press at the feed mechanism until it reaches the position

  of exit, even if the dimensions of the wheels of

  Conveyor drag are variable.

  Another object of the present invention is to provide a conveyor whose length is adjustable in order to maintain alignment or synchronization between the conveyor and another member, the conveyor moving at a constant speed along a path

whose length is adjustable.

  Another object of the invention is to provide a

  conveyor having a fixed length and which is

  born by a drive wheel having a variable diameter and driven by speed drive mwyens

  variable in order to maintain alignment or sync.

  between the conveyor and another body.

  Other objects of the present invention are

  will obviously draw from the detailed description that will

follow of the invention.

  By way of example, the following has been described and illustrated schematically in the accompanying drawings in a form

  preferred embodiment of the invention.

  Figure 1 is a side elevational view

of the printing press.

  FIG. 2 is a plan view of the printing press from which the inking devices have been removed and

wetting devices.

  Figure 3 is a schematic view illustrating the relationship between the conveyor belt and a wheel

  conveyor drive coupled with a roll of

  pressure, with planetary synchronization.

  Figure 4 is a schematic view of a

  voyeur band whose framing is set correctly.

  FIG. 5 is a schematic view similar to FIG. 4, in which the trajectory of the conveyor

tape is too short.

  FIG. 6 is a schematic view similar to FIG. 4 on which the length of the conveyor to

tape is too long.

  Figure 7 is an enlarged sectional view taken along the line 7-7 of Figure 2. Figure 8 is a sectional view

  taken along line 8-8 of Figure 7.

  FIG. 9 is a view in elevation considered

  following the direction of the arrows 9-9 in Figure 7.

  The reference figures are used to

  designate identical parts on all the different

rents figures.

  Referring to -figures. 1, 2 and 3 of the

  In general, the reference 1 designates in a general manner a

  lithographic printing press with perfecting

  polychrome and leaf-fed pressure of the type described in the patent filed in the United States of America

having the No. 3,847,079.

  A feeding or feeding mechanism 2 delimits

  The oscillating gripping member 6 accelerates the individual sheets to bring them to the speed of gripping or gripping bars 8 which are fed from sheets of unprinted paper from a stack 4 to an oscillating gripper. by a transfer mechanism 10

  leaves. The film transfer mechanism 10

  includes drive wheels 12a and 12b

  killed in the vicinity of the extreme end of the alinien-

  tion of the press, and return wheels 14a and 14b located in the vicinity of the output end of the printing press. The wheels carry ribbons or strips 16a and 16b comprising gripping bars 8 mounted between these strips so as to cause the

  individual sheets 5 through the printing press.

  In the embodiment shown, two lathes or printing stations 18 and 20 are provided.

  intended to enable the press to perform an im-

  polychrome pressure at a time. Note that it is possible to use any number of posts

  for printing additional colors

  or for the coating or coating of leaves. The individual sheets 5 are captured by an exit or delivery mechanism 22 when released by the grab bars 8, in order to

  forming a stack 24 of printed sheets.

  As is best represented in the figure

  2, each printing station 18 and 20 has a chaser

  sis 26 located on the side of the operator of the

  press and a side frame 28 located on the side of

  the press, these frames being joined by spacer bars 30 so as to form an extremely rigid frame structure on which different components of the press are mounted. The

  feed mechanism 2 and the delivery mechanism

  this 22 have side frames 2a and 22a located

  on the operator side of the press and side frames

  2b and 22b are located on the side of the drive of the press. Bracing plates 31 connect the side frames of the feed mechanism 2, the printing station 18, the printing station 20 and the

  delivery mechanism 22, in the vicinity of the oppo-

from the printing press.

  Each printing station 18 and 20 is equipped with an upper plate cylinder 38U and a lower plate cylinder 38L, an upper blanket cylinder 48U and a lower blanket cylinder 48L. It appears easily that the upper cylinders

  and 48U and 48L blankets ensure the function

  dual printing rolls and press rollers and waited opposite faces of the sheets - 5, as best shown in Figure 3, said sheets being driven through the printing press by the gripping bars 8 extending enter

the strips 16a and 16b.

  The different blanket cylinders 48U and 48L each delimit one. space 49 of - so as to allow the

  moving between them grab bars 8.

  Note that each plate cylinder 38U and

  38L is equipped with plate locking devices

  to facilitate blocking of a printing plate on these cylinders, and that each 48U blanket cylinder

  and 48L is equipped with locking devices for fixing

a blanket to this cylinder.

  In the embodiment shown, inking systems and wetting systems for ink application and wetting of plates have not been indicated. In addition, alignment or framing adjustment systems were not represented

  circumferential and lateral for the various cylinders

  ders. However, it is considered that it is within the knowledge of a press manufacturer to foresee

other conventional components.

  Furthermore, although the conveyor system is shown in connection with a lithographic printing press, the conveyor can be used in any other rotary printing system, in which for example an image is applied by a printing plate to a cylinder blanket and is pulled

  transferred on a sheet of paper, or is printed directly

  on a sheet from a printing plate.

  planographic press, of a printing press, or of a plate or cylinder of relief or embossing

  In addition, the conveyor system can be used

  with a mechanism for performing operations other than printing, such as cutting, folding, splitting, punching,

reading indices and the like.

  Hereinafter, the transfer mechanism of the sheets will be described in detail. The transfer mechanism sheets 10, described until now briefly, comprises drive wheels 12a and 12b connected

  to an axis 13 situated in the vicinity of the feed mechanism

  2 of the printing press, and the return wheels 14a and 14b rotatably fixed about an axis 15 in the vicinity of the delivery mechanism 22

  or leaving the leaves. Band 16a, which is neighboring

  not on the side of the press operator to print-

  around the wheels 12a and 14a, while the band 16b, located in the vicinity of the driving side of the press, circulates around the wheels 12b and 14b. As will be explained in more detail below, the axis 13 is driven and the traction between the surfaces

  wheels 12a and 12b and the strips 16a and 16b respectively.

  causes the training of the bands.

  The conveyor system 10 is a mechanical device that drives the sheet 5 through the printing press 1. In order to obtain a correct impression, the conveyor system 10 must allow a mechanical repeatability of the sheet with respect to each station

18 and 20.

  The strips 16a and 16b were made, with good results, by a strip of steel 8.89 cm wide and 0.107 cm thick to provide a cross-sectional area of 0.948 cm 2

  for each band. The material of the strip is pre-

  a 1095 carbon steel <designation of EuA) treated by quenching so as to have a Rockwell hardness C 47, and has a modulus of elasticity equal to 2.1.106 kg / cm. The opposite ends of each of the strips of the material are joined together by a seal of the

  type used in aviation, consisting of two

  one of which has a thickness of 0.0508 cm and the other of which has a thickness of 0.08q cm and which are fixed by flat head rivets with a high shear modulus extending into countersunk holes in the band, on opposite sides of the latter. The thinnest plate flexes before the thickest plate so as to distribute the web load and tension to the rivets in a uniform manner to increase the life of the gasket.

tiredness.

  The outer peripheries of the wheels 12a, 12b, 14a and 14b have substantially identical constitutions and each of these wheels has a wheel bead 11 fixed on opposite faces of the wheel so as to provide a groove in which the strips 16 pass. bead 11 prevent only a lateral displacement of the strips 16 relative to the wheels

12 and 14.

  As best shown in FIG. 8, the wheels 14 located at the output or output end of the printing press are freely rotatable about the non-rotational axis 15 and have an inner hub 27 through which is provided a passage intended to receive the outer raceways 18 of bearings 22a and 22b. The inner races 21 of each of the bearings 22a and 22b are fixed to the axis 15. Each axis 15 comprises a hub 15a intended to prevent the bearings 22a and 22a.

  22b to have an outward movement on the axis 15.

  A locking sleeve 28 extends around the outer end of the shaft 15 and is in contact with the

  inner raceway 21 of the outer bearing 22a.

  The sleeve 28 is retained by a locking nut 29

  screwed onto the outer end of a

  rillon 30 located on the outer end of the axis 15.

  The sleeve 28 extends, while being fixed thereto,

  towards an opening 32 formed in a block

  bearing 35, which is fixed by bolts 36 to pins

support 40.

  In order to be certain that the sleeve 28 and the bearing block 35 are attached laterally to each other

  and are situated in a precise relationship, one with

  port to the other, a single adjusting screw 38 is

  seen only on one side of the press.

  Consoles 42 and 44 have spaced apart and aligned openings in which bearings 43 and 45 are attached. The opposite ends of the support pins 40 are fixed with the possibility of sliding

  in bearings 43 and 45 to allow

  The brackets 42 and 44 are secured by means of bolts 46 to the side frames 22a and 22b of the exit mechanism.

or issue 22.

  As shown in FIG. 8, a bearing retainer disk 22c is secured by screws 22d to the wheel 14b, over which the belt passes, to prevent the outer raceway 18 from

  bearing 22a to move outward.

  A grease seal 22e is sealingly applied against the bearing retainer disk 22c and the sleeve 28 so that

  retain the lubricating oil in the vicinity of the

  22a and 22b. Inner tracks

  21 of the bearings 22a and 22b are placed under

  in relation to the external running lanes

  18, by means of the adjustment nut 29, and the outer raceways are separated by a

spacer member 18a.

  The drive wheel 14a is similarly mounted on the opposite end of the axis 15, as

  shown in Figure 9. The wheels are therefore

  independently adjustable and can not

  turn relative to each other.

  Referring to Figure 7 of the drawings, it should be noted that the bracket 44 has an opening in a central portion of the bracket and in which a bearing 50 is secured by means of locking plates 52 and 53 to prevent movement. longitudinal

  the drive screw 55 relative to the console 44.

  The drive screw 55 is of a conventional type and has a ball screw portion 56 formed on

its inner end.

  A ball nut 58 is fixed by screws 59 to an organ 60 which in turn is secured by screws 62.

at bearing block 35.

  The ball screw 56 and the ball nut 58 are of a conventional type and are available in particular from the Saginaw Steering Gear Division of the General Motors Corporation, Actuator Products Group, Saginaw, Llichigan, Ball Screw.

* is a device for transmitting forces and movements

  holding to the family of power transmission screws.It resumes friction with sliding of the power screw

  the rolling friction of the rollers

  ball bearings. The ball bearings circulate in hardened steel tracks or raceways, formed by concave helical grooves formed in the screw and in the nut. All the reaction loads between the screw and the nut are supported by the ball bearings, which ensure the only physical contact between the bodies. When the screw and the nut turn relative to each other, the bearings

  are separated from one end and are

  by ball return and guide tubes at the opposite end of the ball nut. This recirculation allows an unrestricted movement of the nut relative to the screw. The drive screw 55 has a pitch of 0.508 cm per revolution. From the foregoing, it is readily apparent that the rotation of the drive screw 55 prints,

  through the ball nut 58, a displacement

  longitudinally to the bearing block 35, which

  causes a displacement of the axis 15 in a direction

  horizontally in relation to axis 13 located at

  the opposite end of the printing press. The variation

  The length of the strips 16a and 16b is equal to twice the variation of the distance between the axes 13 and 15. Therefore, each complete revolution of the screw 55, which has a pitch of 0.508 cm, would result in a modification of 1.016 cm. the length of the

band 16.

  The drive wheels 12a and 12b, located in the vicinity of the end end of the power supply mechanism of the printing press, are fixed rigidly to the axis 13 which is fixed, with the possibility of rotation, on

  the side frames 2a and 2b of the feed mechanism

  tion. A toothed wheel 66 attached to the end of the shaft 13 is driven by a positive control device

  infinitely variable speed through the medium of

  a return shaft 67 which drives these gear trains

  Nodes 68 and 69 connected to the plate cylinders and the blanket cylinders in the printing stations 18 and 20. The deflection shaft 67 is driven by one

  or more motors 70 connected via the medium

  re appropriate gear trains, V-belts and sleeves as well as gearboxes for

  transmission of speed and driving force

  required for the training of printing stations

249 1895

the conveyor system.

  It will be easy to see that the report of

  between the 48U and 48L printing rolls

  and the drive wheels 12a and 12b can be modified

  set by the speed control device 65 causing a change in the gear ratio.

  the angular velocity of entry of the shaft 67 to the disc

  positive control 65, at the angular velocity of

  of the control device 65 to the axis 13.

  It will be readily apparent that each

  No. 14a and 14b are equipped with a separate screw 55 allowing adjustment of the spacing between

  the axes of the wheels 12a and 14a irrespective of the

  distance between the axes of the wheels 12b and 14b.

  Therefore <the length of the bands 16a and 16b is

independently adjustable.

  Note that the length of the strips 16a and 16b can be adjusted by moving a third

  and / or a fourth wheel 14 ', 14 n available either

  above, either below one of the strands of the bands

  16a or 16b, as shown in FIG. 4.

  The initial tension of the strip was chosen equal to 816.4 kg for each strip. This tension is obtained by making the individual strips into

  giving them a length less than the length ins-

  desired height. Each band is lengthened during

  its assembly being brought to the desired length.

  As described above, the distance between

  the axes of the wheels 12a and 14a is adjustable from

  to bring the tape to the final length.

  A conveyor system that was constructed to perform tests used wheels 12a, 12b, 14a and 14b having a diameter of 121.813 cm plus the thickness of the strip, which was 0.107 cm, and thus provided a valuable pitch diameter. nominal

  121,920cm. The length of the band driven by each

  drive wheel 12a and 12b during a cycle

  is equal to 121.920 cm multiplied by s. The value

  obtained is equal to about 383.022cm. Theo-

  The diameter of the conveyor wheels 12a and 12b of the 38U and 38L roll conveyor diameter of 40.640 cm was 3: 1, while the ratio of the drive wheel to a 24-bar grabber is equal to 8: 1. By multiplying 383,022cm by

  8, 3064.181 cm is obtained for the final nominal length.

  the band. The manufactured length of the belt to obtain a prestressing load of 816.4 kg

  on the band was equal to 25.1227 times 121.92Q, that is,

  say 3062.956cm, lower figure of 1.250cm to the installed length of the band. Using the equation _PL at = -, where A is equal to 1, 25, L is equal to

AE 2

  3064.181 cm, λ = 0.042 × 3.5 × 6.4516 cm and E = 2.10 × 10 6 kg / cm 2, the load P is equal to 816.4 kg. Since the final length of the belt is calculated as a function of the diameter of the drive wheel 12a and 12b, it can be seen that it is not possible to manufacture the wheels by keeping them in place.

  exactly the same diameter, or that the length

  The width of the driven web can not be exactly the same as the length provided by the distance between the drive wheel and the idler wheel to move the grip bars 8 through the printing press. In addition, the return wheels 14a and 14b can not be given exactly the same diameter as the drive wheels 12a and 12b. Therefore, two pairs or two systems of bands and wheels can not function identically in practice. This is why the return wheels 14a and 14b are mounted so that they can rotate independently of one another

  at the exit end of the press.

  Fixed length strips can therefore only work on wheels of fixed dimensions and with fixed center-to-center distances between these wheels, said dimensions can not be

obtained and / or maintained.

  The axis 13 located at the end of the feed mechanism side of the press is driven, as previously described, and this axis is fixed to maintain the axis 15 in an established position. This is desirable since the

  oscillating gripping members 16 must be aligned

  with the conveyor 10 for feeding the sheets to the latter. Thus, by keeping the driven shaft 13 in a fixed position, it is possible to achieve and maintain

  alignment or framing between the feeding mechanism

  2, and the conveyor 10. Furthermore, since the opposite ends of the shaft 15 can be moved independently by screws 55, the axis 15 will not necessarily be maintained in a precisely aligned parallel position. with

the drive shaft 13.

  The drive wheels 12a and 12b are

  rigidly to the drive shaft 13 so as to maintain the synchronism of the band 16a with respect to the band 16b. However, the synchronization of the return wheels 14a and 14b relative to each other is

  a variable that we can not predict. As a result

  in the embodiment shown, the

  two return wheels 14a and 14b can rotate freely

  independently of each other since their rotational speed will vary depending on the

  effective diameter of the respective wheels.

  As previously described, the

  main function of the conveyor system is to ensure

  The repeatability of the webs 16a and 16b of the conveyor relative to the drive wheels 12a and 12b occurs every 8 rotations of the drive wheels. That is why the length of the band is equal to 8 times the theoretical value of the circumference of the drive wheels

12a and 12b.

  Assuming that the length of the band 16a

  or 16b is not exactly equal to eight times the cir-

  12a and 12b drive wheel conference, the mechanical return every eight rotations of the drive wheels 12a and 12b will not occur. not. During each cycle of the strips 16a and 16b, an error will be corrected in the return of the drive wheels 12a and 12b in position relative to the strips 16a and 16b. Yes

  we control this error, we will see that its value-

  will accumulate at each cycle depending on the error in the distance between the centers of the axes 13 and 15 or the error concerning the length of the strip. The real relation that links the repeatability error to the distance between the centers of the axes is that this error is equal to twice the error

  distance between the centers. For example, the distance

  this between the centers is higher or lower than

  0.00254 cm to what it should be, after a revolution

  complete, the repetition error of the belt and the drive wheel will be 0.00508 cm. An initial position error could also exist when mounting the band on the wheel. In other words, the band could initially be misplaced with respect to the wheel 12a or 12b, even if the distance between the centers of the axes 13 and 15 is correct. In this case, the error should not accumulate with each rotation of the drive wheel, but should remain constant. The initial tension of 816.4 kg in the bands

  16a and 16b is established and maintained for two reasons.

  First of all we must guarantee the traction capacity

  between the band and the wheel in such a way that

  no slip between the drive wheels

  12a and 12b and the strips 16a and 16b. The tractive force

  tion is a function of the multiple coefficient of friction

  tiplied by the normal force on the surface of the drive wheels 12a and 12b. Secondly, the tension of the belts 16a and 16b is necessary in order to prevent a loss of tension or friction drive force during the normal increase of the temperature of the conveyor system under normal operating conditions. Assuming for example

  that the belts 16a and 16b of the conveyor have been manufactured

  at an ambient temperature of 22.20C with a

  3062, 9562 cm and assuming that the band

  length of 6.10-6 cm per centimeter of length for 0.55 OC, one could then suppose that an increase of 11.10C from 22.2-C to 33.31C results in an increase of 0.3675cm of the length of the band

  16a or 16b of the conveyor. This would result in a reduction

  the voltage equal to the difference between 816.4 kg for an arrow of 1.2502om and 578.026kg for an arrow of 0.8844-m. Although the length of the tape

  16a or 16b rise does not change since the

  The voltage is still maintained in the band, the voltage would fall to 578,026 kg as a result of the increase of the ambient temperature. It should be noted that the length of the tape would not vary until the voltage

  actually falls to 0 kg, and would then begin to increase

  b. Referring to Figure 3 of the drawings,

  note that the conveyor belts.16 are

  xible and flow on drive wheels 12 and - return 14 so as to form a closed loop. In FIG. 3, the dotted strips 16 are represented in the form of a strip

  in the form of a ring or a circular loop 16 '

  with a smooth surface rolling on the smooth surface of the drive wheel 12 '. The drive wheel 12 'rotates about the axis 13' so as to print a

rotation to the band 16 '.

  Assuming no slips occur

  between the surfaces of the drive wheel 12 'and the web 16', the circumference of the circle 16 'must be equal to an exact multiple of the circumference of the circle 12' for the respective circles so as to obtain a return to the precise position represented in

end of a rotation of the circle 16 '.

  However, note that if the diameter of the circle

  12 'varies for some reason while the diameter

  circle 16 'remains unchanged, the two circles do not

  will not come in the precise nositicn after a rota-

  complete circle 16 '. For example, the circle 12 'has a diameter of 121.92 cm and is made of a material having a coefficient of expansion.

  of 6.10-6 cm for every centimeter of

  per 0.55e0C, the length of the circumference

  circle 12 'will vary from 0.0023 cm to

a variation of 0.55 0C.

  Assuming that the temperature increased by 0.55 ° C, the diameter of the circle 12 'would increase from 121.92 cm to 121.9223 cm. If the angular velocity of the drive wheel 12 'has remained exactly the same as the angular velocity of the printing roller 48', it will be noted that the belts 16 'will not be synchronized

  correctly with the print roller 48 '.

  However, if the angular velocity of the wheel 12 'is changed with respect to the angular velocity of the

  printing roll 48 'by means of a setting of the

  Positive control and infinitely variable speed control system 65, as previously described, the belt 16 'and the printing roller 48' can be moved in synchronism even if the diameter of the wheel

12 'drive has changed.

  Assuming that the angular velocity of the wheel

  the printing water 48 'and the drive wheel 12' remain unchanged, the web 16 'can be moved in synchronism with the printing roller 48' by a change in the circumference of the web 16 '

  in order to absorb the variation in the length of the circuit

  12 'drive wheel conference.

  The misalignment or misalignment of the sheet carried by the grab bars 8 compared

  48U and 48L print rollers can be

  by a variety of means, including the observa-

  leaves at the delivery or exit end of the printing press. If the diameter of the drive wheel 12 has varied as a result

  thermal expansion which resulted in a displacement

  conveyor belts 16 at an incorrect speed.

  compared to the 48U and 48L print rollers, the error is. will grow and increase with every revolution

  of the press to print. When the error becomes apparent

  During the inspection of the printed sheets, the press operator can either adjust the superficial speed of the drive wheels 12a and 12b by adjusting the speed control device 65 so that the conveyor belts are driven at the same time. the correct superficial velocity is to rotate the drive screw 55 so as to adjust the length of the strips 16 with respect to the circumference of the wheel

249 1895

  12 to align or frame the sheets conveyed by the conveyor relative to the

printing roll.

AT

Claims (10)

  1. Method for synchronizing the rotation of   two members (12a, 12b; 16a, 16b) which have   endless surfaces rolling on one another, the dimnsions of one of said organs being variable, characterized in that it consists in adjusting the ratio of the length of the first surface   endless at its superficial velocity of   that this ratio is equal to a multiple of the ratio of the length of the second endless surface   at the superficial speed of the latter.   2. Process according to claim 1, characterized   in that the first organ length (12a, 12b) responds to a second organ variation (16a, 16b 3. Method according to se in that the length ne (12a, 12b; 16a, 16b) variation of the second organ length (16a, 16b 4. The method according to wherein the speed of the surface on the 16a, 16b) is set to the superficial velocity of 12a, 12b). claim 1, characterized from the surface of the first organ-   is set in response to one of the surface on the 12a, 12b). claim 1, characterized the first organization   ne (12a, 12b; 16a, 16b) is adjusted in response to a variant of the superficial velocity of the second member (16a, 16b; 12a, 12b),   5. Process according to claim 1, characterized   in that the superficial velocity of the first organism   ne (12a, 12b; 16a, 16b) is adjusted in response to a change in the length of the surface of the second organ (16a, 16b, 12a, 12b).   6. Process according to claim 1, characterized   in that the first member (16a, t6b) is a strip   and that the second member (12a, 12b) is an impeller   applied in such a way as to cause friction the band.   7. Process according to claim 6, characterized   in that the length of the strip (16a, 16b) is set to a value which is an exact multiple of the   circumference of a printing roll (48U; 48L).   8. Process according to claim 6, characterized   in that the angular velocity of the drive wheel   (12a, 12b) is set in relation to the speed   angle of a printing roll (48U, 48L) of   to move the sheets carried by the web (16a, 16b) in an aligned or square manner with respect to with the printing roller (48U, 48L).   9. Device for driving a sheet of paper (5) towards a printing roll (48U; 48L) in a printing press (1), characterized in that it comprises wheels (12a, 12b, 14a) , 14b) spaced and aligned, journalled so as to be rotatable in the vicinity   each end of the press (1); flexible bands   continuous wheels (16a, 16b) circulating on the wheels on each side of the press and rotatable with the wheels, means (13, 65) for rotating the wheels (12a, 12b) at one end of the press (1 ), many   spaced bars (8) for gripping, means permitting   setting to fix the opposite ends of the bars   (8) to the strips (16a, 16b). and means (50 to 60)   setting the spacing between the drive wheels   ment. to change the length of the strips (16a, 16b) to synchronize the sheets (5) carried by the grab bars (8) with the printing roller (48U, 48L).   10. Device according to claim 9, characterized   characterized in that the means (13, 65) for rotating the wheels (12a, 12b) comprise means (65) for adjusting the angular speed of the drive wheel when the diameter of the latter varies, in order to synchronize the strips (16a, 16b) with the printing roller (48U, 48L).