Anti-expansion web-transfer mechanism for a color press

Information

  • Patent Grant
  • 6244182
  • Patent Number
    6,244,182
  • Date Filed
    Wednesday, October 27, 1999
    25 years ago
  • Date Issued
    Tuesday, June 12, 2001
    23 years ago
Abstract
An anti-expansion web-transfer mechanism mounted between two printing units in a color press to transfer a printed web from one printing unit to a next printing unit, and to prevent the printed web from expanding in width, the anti-expansion web-transfer mechanism including a fixed axle and a rotary axle arranged in parallel between two brackets, a plurality of roller supports respectively mounted on the two axles in stagger to hold a respective roller, a transmission mechanism controlled to rotate the rotary axle, enabling the rollers at the roller supports at the rotary axle to be pressed on the printed web against the rollers at the roller supports at the fixed axle, and an air cylinder connected between the transmission mechanism and one roller support at the rotary axle.
Description




BACKGROUND OF THE INVENTION




The present invention relates to a color press, and more specifically to an anti-expansion web-transfer mechanism mounted between two printing units in a color press to transfer the web from one printing unit to a next printing unit, and to prevent the printed web from expanding in width.




When processing a color printing in a color press, the web is printed color by color through different printing units in the press. When printed through one printing unit, the web may expand in width due to absorption of ink and water. As illustrated in

FIG. 1

, if the width of the web expands from set width D to expanded with D', the web becomes unable to be accurately moved over the printing plate at the next printing unit. When this condition occurs, the printing plate at each printing unit must be respectively adjusted to fit the expanded web. However, it is complicated to adjust the position of the printing plate at each printing unit.




SUMMARY OF THE INVENTION




It is the main object of the present invention to provide an anti-expansion web transfer mechanism for a color press, which prevents the printed web from expanding in width. According to one aspect of the present invention, the anti-expansion web-transfer mechanism comprises a fixed axle and a rotary axle arranged in parallel between two brackets, a plurality of roller supports respectively mounted on the two axles in stagger to hold a respective roller, a transmission mechanism controlled to rotate the rotary axle, enabling the rollers at the roller supports at the rotary axle to be pressed on the printed web against the rollers at the roller supports at the fixed axle, and an air cylinder connected between the transmission mechanism and one roller support at the rotary axle. According to another aspect of the present invention, the transmission mechanism comprises a mounting block pivoted to one bracket, a nut mounted in the mounting block, a driven gear fixedly mounted on the nut outside the mounting block, a screw rod threaded into the nut, the screw rod having a coupling portion extended from one end thereof and coupled to one roller support at the rotary axle through the air cylinder, a stop block fixedly mounted on the coupling portion of the screw rod and stopped at one side of the bracket to which the mounting block is connected, a motor mount fastened to the mounting block at a bottom side, a reversible motor mounted on the motor mount, and a driving gear meshed with the driven gear and driven by the reversible motor to rotate the driven gear.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic drawing showing the web expanded in width after absorption of ink and water.





FIG. 2

is a perspective view of the present invention.





FIG. 2A

is an enlarged view of a part of FIG.


2


.





FIG. 2B

is a sectional view in an enlarged scale of a part of

FIG. 2

, showing the mounting block of the transmission mechanism coupled to the first bracket.





FIG. 3

is a schematic drawing showing the roller support adjusted relative to the axle according to the present invention.





FIG. 4

is a side view in section of the present invention.





FIG. 5

is an applied view of the present invention, showing the piston extended out, the roller supports turned with the first axle away from the web.





FIG. 6

is schematic top view, showing the rollers pressed on both sides of the web, the web corrugated.





FIG. 7

is another side view in section of the present invention, showing the web delivered through the gap between the first axle and the second axle, the rollers pressed on both sides of the web.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring to

FIGS. 2

,


2


A,


2


B,


3


and


4


, the present invention comprises a first bracket


102


and a second bracket


104


fixedly arranged in parallel, a first axle


12


and a second axle


14


coupled in parallel between the brackets


102


and


104


, a plurality of roller supports


20


respectively mounted on the axles


12


and


14


in a staggered manner, a plurality of rollers


252


respectively mounted on the roller supports


20


, and a transmission mechanism


30


mounted on the first bracket


102


. The roller supports


20


each comprise a clamping hole


22


, which receives the axle


12


or


14


for enabling the respective roller support


20


to be about the axle


12


or


14


(see FIG.


3


), a tightening up screw


24


controlled to fix the respective roller support


20


to the axle


12


or


14


and to stop the respective roller support


20


from rotary motion relative to the axle


12


or


14


, a substantially U-shaped opening


26


at one end, two axle holes


262


aligned at two opposite lateral sides of the U-shaped opening


26


, and a pivot


264


mounted in the axle holes


262


to hold a respective roller


266


.




Referring to

FIGS. 2A and 2B

, the transmission mechanism


30


comprises a mounting block


32


pivoted to the first bracket


102


, the mounting block


32


comprises a mounting shaft


322


raised from one lateral side thereof and inserting through a through hole at the first bracket


102


in direction from the front side wall of the first bracket


102


toward the back side wall thereof, a clamp


324


mounted on the mounting shaft


322


and stopped at the back side wall of the first bracket


102


to secure the mounting block


32


to the first bracket


102


, enabling the mounting block


32


to be turned with the mounting shaft


322


in the through hole at the first bracket


102


, a cylindrical nut


34


mounted in a through hole at the mounting block


32


, a clamp


342


fastened to the cylindrical nut


34


and stopped at one side of the mounting block


32


to secure the nut


34


to the mounting block


32


, a driven gear


344


fixedly mounted on the cylindrical nut


23


and disposed at one side of the mounting block


32


opposite to the clamp


342


, a screw rod


36


threaded into the screw hole


346


in the cylindrical nut


34


, the screw rod


36


having a coupling portion


362


at one end, a stop block


364


fixedly mounted around the coupling portion


263


of the screw rod


36


and stopped against the front side wall of the first bracket


102


, an air cylinder


40


connected to the coupling portion


362


of the screw rod


36


, the air cylinder


40


having a movable end, namely, the piston rod


42


pivoted to the pivot


264


at one roller support


20


at the first axle


12


, a motor mount


326


fastened to the mounting block


32


at a bottom side, a reversible motor


38


mounted on the motor mount


326


, and a driving gear


384


coupled to the output shaft of the motor


38


and meshed with the driven gear


344


(see FIG.


4


).




Referring to

FIGS. 5 through 7

, the present invention is mounted between two printing units in a color press. During printing, web A is transferred forwards through the gap between the first axle


12


and the second axle


14


. When passing through the gap between the axles


12


and


14


, the web A is stretched into a corrugated condition by the rollers


266


at the roller supports


20


at the axles


12


and


14


(see FIG.


6


), thereby causing the apparent width, the distance between opposing longitudinal sides, of the web A to be adjusted to the set dimension X. Therefore, after being passed through one printing unit in the color press, the web A is automatically forced by the rollers


266


to reduce the distance between the sides and thereby adjust its otherwise expanded width (due to absorption of ink) to an apparent width having the set dimension X between receiving a next printing process at a next printing unit. When the web A is transferred through the gap between the axles


12


and


14


, the reversible motor


38


is started to turn the driven gear


344


via the driving gear


384


, thereby causing the screw rod


36


to be moved forwards in the nut


34


. When the screw rod


36


is moved forwards, the corresponding roller support


20


is pulled by the piston rod


42


of the air cylinder


40


, thereby causing the first axle


12


to be rotated on its own axis through an angle relative to the second axle


14


, and therefore the rollers


266


at the roller supports


20


at the first axle


12


are pressed on the web A against the rollers


266


at the roller supports


20


at the second axle


14


.




The web used in the color press is a continuous sheet of paper rolled up into a roll. When one roll of paper is used up, a second roll of paper is installed in the color press for printing. Because different rolls of paper have different tensile strength, different pressure should be employed to the web through the rollers


266


subject to the tensile strength of the web. By means of controlling the operation of the reversible motor


38


to move the air cylinder


40


, the first axle


12


can be quickly rotated to the desired angle by the piston rod


42


of the air cylinder


40


. Further, by extending the piston rod


42


out of the air cylinder


40


, the first axle


12


is rotated to move the rollers


266


at the roller supports


20


at the first axle


12


away from the web A passing through the gap between the axles


12


and


14


.




While only one embodiment of the present invention has been shown and described, it will be understood that various modifications and changes could be made thereunto without departing from the spirit and scope of the invention disclosed.



Claims
  • 1. An anti-expansion web-transfer mechanism mounted between two printing units in a color press to transfer a web from one printing unit to a next printing unit, and to prevent the printed web from expanding in width, the anti-expansion web-transfer mechanism comprising:a first bracket and a second bracket fixedly arranged in parallel; a first axle coupled between said first bracket and said second bracket and rotated on the axle thereof; a second axle fixedly connected between said first bracket and said second bracket and arranged in parallel to said first axle, said second axle defining with said first axle a web-transfer gap through which the printed web is delivered; a plurality of roller supports respectively mounted on said first axle and said second axle, said roller supports each comprising a clamping hole, which receives one of said first axle and said second axle, a tightening up screw fastened up to fix the respective roller support to said first axle or said second axle and to stop the respective roller support from rotary motion relative to the respective axle; a plurality of rollers respectively mounted on said roller supports; a transmission mechanism controlled to rotate said first axle, enabling the rollers at the roller supports at said first axle to be pressed on the printed web in a direction opposite to the rollers at the roller supports at said second axle, said transmission mechanism comprising a mounting block pivoted to said first bracket, a nut mounted in said mounting block, a driven gear fixedly mounted on said nut and disposed outside said mounting block, a screw rod threaded into said nut, said screw rod having a coupling portion extended from one end thereof and coupled to one roller support at said first axle, a stop block fixedly mounted on the coupling portion of said screw rod and stopped at one side of said of said first bracket, a motor mount fastened to said mounting block at a bottom side, a reversible motor mounted on said motor mount, and a driving gear meshed with said driven gear and driven by said reversible motor to rotated said driven gear; and an air cylinder connected to the coupling portion of said screw rod, said air cylinder having a piston rod pivoted to one roller support at said first axle.
  • 2. The anti-expansion web-transfer mechanism of claim 1 wherein said roller supports are respectively mounted on said first axle and said second axle in stagger.
  • 3. The anti-expansion web-transfer mechanism of claim 1 wherein said first axle and said second axle are arranged in parallel on a plane perpendicular to the moving direction of the printed web passing through the gap between said first axle and said second axle.
  • 4. The anti-expansion web-transfer mechanism of claim 1 wherein said roller supports each comprise a substantially U-shaped opening at one end, two axle holes aligned at two opposite lateral sides of said U-shaped opening, and a pivot mounted in said axle holes to hold one of said rollers.
US Referenced Citations (3)
Number Name Date Kind
5598778 Iijima et al. Feb 1997
5678484 Callan et al. Oct 1997
5820122 Schneider Oct 1998
Foreign Referenced Citations (2)
Number Date Country
8-156234 Jun 1996 JP
9-216334 Aug 1997 JP