METHOD AND APPARATUS FOR MANUFACTURING PRE- PRINTED AND POST-FORMED DESIGN TAB END USING PILOT HOLES Technical Field The present invention relates to a method and an apparatus for manufacturing a pre-printed and post-formed type design tab end using pilot holes, and more particularly to a method and an apparatus for manufacturing a pre- printed and post-formed type design tab end using pilot holes, in which pilot holes are formed in a tab coil by a pilot hole punching press at the same pitches as by a conversion press, design patterns are printed on the tab coil at precise locations and at uniform pitches using a back-up roll provided with pitch guide pins and a print cylinder roll provided with elastic members such as silicon or rubber or pilot pin die holes, and then tabs are formed on the tab coil by the conversion press so that the tabs with a closed finger hole are located at correct positions of the corresponding design patterns.

Background Art As well known to those skilled in the art, drinking cans are generally used to contain drinking water and beverages for a long period of time and to be easily handled. These drinking cans store carbonate water and soda, fruit juice, mixed beverage, beer, etc. Conventionally, each of such drinking cans comprises a main body formed to have a cylindrical shape and made of a metal such as steel or a nonferrous metal such as aluminum, an aluminum end attached to the top portion

of the main body, and a score line formed in the surface of the aluminum end so that the score line is easily torn off to form an opening. The drinking can further comprises a tab formed on the end, which serves to press the score line to open the can for drinking.

Therefore, in order to drink the contents of the can, a user draws the tab so that the score line formed in the end is torn off. Here, the beverage contained in the can is discharged to the outside via the opening formed by tearing off the score line, and then easily drunk by the user.

There are several examples of a method for manufacturing a design tab end for a drinking can, as follows. Korean Patent Application No. 10-2001- 43268, which was filed by the present inventor (s) on February 17,2001 and then laid-open, discloses an apparatus for adjusting phases in design printing using a sensor for sensing tolerance of a print roll. Korean Patent Application No. 10- 2001-59438, which was filed by the present inventor (s) on September 25,2001 and then laid-open, discloses a method for manufacturing a design tab end using pilot holes formed in a tab coil. Such method comprises a step for operating the earlier phase adjusting apparatus, which was filed on February 17, 2001.

Further, Korean Patent Application No. 10-2002-9454, which was filed by the present inventor (s) on February 22,2002 and then laid-open, discloses a method for manufacturing a pre-printed and post-formed type and silk screen printed type design tab end using pilot holes formed in a tab coil.

The above-described print roll type printing apparatus and method damage final products due to the generation of accumulated tolerance, and the above-described silk screen printed type printing method is not suitable for application to mass production.

Disclosure of the Invention Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method and an apparatus for manufacturing a pre-printed and post-formed type design tab end using pilot holes, in which pilot holes are formed in a tab coil by a pilot hole punching press by the same pitches as by a conversion press, design patterns are printed on the tab coil at precise locations and by uniform pitches using a back-up roll provided with pitch guide pins and a print cylinder roll provided with pilot pin die holes or elastic members made of a material such as silicon or rubber, and then tabs are formed on the tab coil by the conversion press so that the tabs with a closed finger hole are located at correct positions of the corresponding design patterns.

It is another object of the present invention to provide a method and an apparatus for manufacturing a pre-printed and post-formed type design tab end using pilot holes, in which it is possible to mass-produce tabs on which a design such as a logo and a character of a newly launched brand can be printed, and to print a design for a free gift event and promotion at a precise position on a rear side of the tabs during the transferring of the tab coil.

In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of an apparatus for manufacturing a pre-printed and post-formed type design tab end using a plurality of pilot holes formed in a tab coil in a longitudinal direction, comprising: an uncoiler for unwinding the tab coil ;

a pilot hole punching press for forming the pilot holes in the tab coil; a tab coil feeder for transferring the tab coil provided with the pilot holes; a pitch roll in-feeding unit rotated and provided with pins inserted into and released from the pilot holes so as to provide the tab coil at a uniform pitch; a cylinder roll printer for printing designated design patterns on the tab coil provided at the uniform pitch, provided with pilot pins protruded from the outer circumference thereof; a back-up roll located close to the lower surface of the cylinder roll printer and provided with pilot holes formed in the outer circumference thereof correspondingly to the pilot pins protruded from the outer circumference of the cylinder roll printer; a pitch roll out-feeding unit paired with the pitch roll in-feeding unit for feeding the tab coil at a uniform pitch; a tab coil out-feeder for discharging the tab coil passing through the pitch roll out-feeding unit; a re-coiler for winding the tab coil; and a conversion press for forming tabs and shells around the tabs.

Preferably, pilot holes may be formed in the outer circumference of the cylinder roll printer, and pilot pins may be formed on the back-up roll located close to the lower surface of the cylinder roll printer.

Further, preferably, elastic members made of a material such as silicon or rubber may be provided on the outer circumferences of the cylinder roll printer and the back-up roll.

In accordance with another aspect of the present invention, there is provided a method for manufacturing a pre-printed and post-formed type design

tab end using a plurality of pilot holes formed in a tab coil in a longitudinal direction, by means of an apparatus including an uncoiler for unwinding the tab coil, a pilot hole punching press for forming the pilot holes in the tab coil, a tab coil feeder for transferring the tab coil provided with the pilot holes, a pitch roll in- feeding unit rotated and provided with pins inserted into and released from the pilot holes so as to provide the tab coil at a uniform pitch, a cylinder roll printer for printing designated design patterns on the tab coil provided at the uniform pitch, provided with pilot pins protruded from the outer circumference thereof, a pitch roll out-feeding unit paired with the pitch roll in-feeding unit for feeding the tab coil at a uniform pitch, a tab coil out-feeder for discharging the tab coil passing through the pitch roll out-feeding unit, a re-coiler for winding the tab coil, and a conversion press for forming tabs and shells around the tabs, comprising the steps of : (a) perforating the tab coil fed by the uncoiler so as to form the pilot holes in the tab coil; (b) transferring the tab coil provided with the pilot holes at a uniform pitch by inserting and releasing the pins of the pitch roll in-feeding unit into and from the pilot holes; (c) transferring the tab coil fed from the pitch roll in-feeding unit and simultaneously printing patterns on the tab coil by inserting and releasing the pilot pins protruded from the outer circumference of the cylinder roll printer into and from pilot holes formed in a back-up roll located close to the lower surface of the cylinder roll printer; (d) drying the surface of the tab coil provided with the printed patterns by driers installed in the cylinder roll printer;

(e) transferring the tab coil provided with patterns printed by the cylinder roll printer at a uniform pitch by inserting and releasing pins of the pitch roll out- feeding unit into and from the pilot holes; (f) recoiling the transferred tab coil; (g) uncoiling the tab coil so as to be fed to the conversion press; and (h) forming tabs from the fed tab coil and forming shells around the tabs.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic view of a production line using an apparatus for manufacturing a cylinder roll-printed type design tab end using pilot holes formed in a tab coil in accordance with an embodiment of the present invention; Fig. 2 is a schematic view of a tab coil feeding unit and a cylinder roll printer; Fig. 3 is a partially enlarged side view of the cylinder roll printer of Fig. 2; Fig. 4 is a partially enlarged side view of a cylinder roll printer using a print cylinder roll provided with elastic members or pilot pin die holes instead of a back-up roll provided with pitch guide pins; Fig. 5 is a schematic view of a tab coil processed by a process for manufacturing a design tab end in accordance with an embodiment of the present invention; and Fig. 6 is a flow chart illustrating a process for manufacturing a design tab

end in accordance with an embodiment of the present invention.

Best Mode for Carrying Out the Invention Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.

Fig. 1 is a schematic view of a production line using an apparatus for manufacturing a cylinder roll-printed type design tab end using pilot holes formed in a tab coil in accordance with an embodiment of the present invention.

With reference to Fig. 1, in order to precisely set pitches in a tab coil 2 required in a design-printing step and a tab-forming step prior to the design-printing step, the tab coil 2 installed in an uncoiler 4 is fed to a pilot hole punching press 6 by a tab coil feeder 8 at uniform speed, and then pilot holes (201 in Fig. 4) with uniform shapes are formed in the tab coil 2 at designated intervals.

The pilot hole punching press 6 is a set of mold dies for forming the pilot holes in the tab coil 2. In case that one lane of tabs will be formed in the tab coil 2, the mold die, the pilot hole punching press 6 generally includes one pilot punch (not shown), a plurality of pilot pins (not shown) continuously formed in a straight line, and a reform punch for leveling protruding portions on the lower surface of the tab coil 2 generated when the pilot holes 201 are formed in the tab coil 2 by means of the above pilot punch. The pilot punch, the pilot pins, and the reform punch are integrally formed.

Here, each of the pilot punch, the pilot pins, and the reform punch are prepared in a number corresponding to the number of lanes of the tabs desired to be printed and formed in the tab coil 2.

Next to the pilot hole punching press 8, there are provided a washer 10 for washing the surface of the perforated tab coil 2 and a dryer 12 for drying the washed tab coil 2.

After the tab coil 2 is washed and dried via the washer 10 and the dryer 12, the tab coil 2 is fed to a cylinder roll printer 16 by means of a pitch roll in-feeding unit 14 so that design patterns are printed and tabs are formed at the same positions and pitches on the tab coil 2 in the design pattern-printing step and the tab-forming step.

The tab coil 2 passing through the pitch roll in-feeding unit 14 is fed into the cylinder roll printer 16 at uniform pitches between the pilot holes. The cylinder roll printer 16 serves to print design patterns on the tab coil 2 and then dry the tab coil 2 provided with the printed patterns. Then, the tab coil 2 is wound on a re- coiler 22 so that uniform pitches between the pilot holes formed in the tab coil 2 are maintained by means of a pitch roll out-feeding unit 18. Thereby, the design patterns-printing step of the tab coil 2 is completed.

Here, the tab coil feeder 8 and a tab coil out-feeder 20 serve as loopers for connecting the tab coil 2, transferred by the continuous operation of the pilot hole punching press 6 and the re-coiler 22, to the cylinder roll printer 16 for printing designated design patterns on the surface of the tab coil 2.

After the printing step, the tab coil 2 is wound on an uncoiler (not shown) of a conversion press for forming tabs in the tab coil 2. Then tabs are formed in the tab coil 2 by the conversion press (not shown).

Here, since the pilot holes 201 are already formed in the tab coil 2 using the pilot hole punching press 6 prior to the printing step, a pilot hole-punching step is omitted. The pitches in the tab coil 2 in the design pattern-printing step and the

tab-forming step are the same by coupling the pilot holes 201 with a plurality of pilot pins of a set of mold dies of the conversion press.

Fig. 2 is a schematic view of a tab coil pitch roll feeding unit and a cylinder roll printer. Fig. 3 is a partially enlarged side view of the cylinder roll printer of Fig. 2. Fig. 4 is a partially enlarged side view of a cylinder roll printer using a print cylinder roll provided with elastic members or pilot pin die holes instead of a back-up roll provided with pitch guide pins.

With reference to Figs. 2 to 4, a tab coil pitch roll 147 is installed in the pitch roll in-feeding unit 14. Pitch guide pins 142 are protruded along the outer circumference of the rotated tab coil pitch roll 147.

The pitch guide pin 142 is tapered so that the diameter of the end of the pitch guide pin 142 is smaller than those of other portions of the pitch guide pins 142. Accordingly, the tab coil pitch roll 147 can adapt to the small change of the location of the tab coil 2 and the variation of the length of the tab coil 2 due to the thermal expansion and contraction during the transferring of the tab coil 2, and the tab coil 2 can pass through a space between the pitch roll 147 and a pitch back-up roll 143 and then be transferred at constant pitches.

When the tab coil 2 provided with the pilot holes 201 is transferred between the back-up roll 143 provided with the pitch guide pins 142 and the print cylinder roll (not shown) provided with elastic members (not shown) made of a material such as silicon or rubber or the pilot pin die holes, the generation of accumulated tolerance in the tab coil 2 is prevented. Accordingly, it is possible to print design patterns at precise positions on the tab coil 2.

In the present invention, when the tab coil pitch roll 147 is rotated, the pitch guide pins 142 attached to the outer circumference of the tab coil pitch roll 147 are

alternately inserted into and released from the pilot holes 201 formed in the tab coil 2, thus preventing the generation of accumulated tolerance of the pattern positions printed on the tab coil 2 due to the thermal expansion or contraction of the tab coil 2.

Further, when the tab coil 2 is transferred from the pitch roll in-feeding unit 14 to the pitch roll out-feeding unit 18, the tab toil 2 is transferred between the back-up roll 143 provided with the pitch guide pins 142 and the print cylinder roll provided with the elastic members made of silicon or rubber or the pilot pin die holes, thus preventing the generation of accumulated tolerance of the pattern position to be printed on the tab coil 2 without stoppage, and allowing the design patterns to be printed at the precise positions on the tab coil 2.

Here, the tab coil 2 is not transferred by the friction between the pitch roll 147 and the pitch back-up roll 143, but transferred only by the operation of the pitch roll 147. Preferably, the surface of the pitch back-up roll 143 is made of an elastic member made of silicon or rubber.

As shown in Fig. 3, elastic members made of silicon or rubber, or pilot holes 163 are protruded from the outer circumference of the cylinder roll printer 16.

When the tab coil 2 is transferred, the generation of accumulated tolerance of the pattern position to be printed on the tab coil 2 is prevented by coupling the pilot pins 163 with pilot pin insertion holes (not shown) formed in a back-up roll 164 located close to the pilot pins 163.

Alternately, pilot pin insertion holes (not shown) with uniform sizes may be formed in the outer circumference of the cylinder roll printer 16, and pilot pins may be protruded from the outer circumference of the back-up roll 164 located close to the outer circumference of the cylinder roll printer 16.

After the tab coil 2 passes through the pitch roll in-feeding unit 14, uniform

design patterns are printed on the outer surface of the tab coil 2 by the cylinder roll printer 16. The design patterns printed on the tab coil 2 are dried by a plurality of dryers 166 provided in the cylinder roll printer 16, and simultaneously the tab coil 2 is transferred toward the pitch roll out-feeding unit 18.

In the present invention, the generation of accumulated tolerance of the pattern position to be printed on the tab coil 2 is also prevented by the cylinder roll printer 16 and the back-up roll 164 located close to the lower surface of the cylinder roll printer 16. Therefore, it is possible to transfer the tab coil 2 as well as to precisely print the design patterns on the tab coil 2.

Fig. 5 is a schematic view of a tab coil processed by a process for manufacturing a design tab end in accordance with an embodiment of the present invention. Fig. 6 is a flow chart illustrating a process for manufacturing a design tab end in accordance with an embodiment of the present invention.

First, the tab coil 2 wound on the uncoiler 4 is fed to the pilot hole punching press 6 at a uniform speed, and then the pilot holes 201 with designated shapes such as circle or rectangle are formed in the tab coil 2 at uniform intervals (ST-100).

The tab coil 2 provided with the pilot holes 201 formed by the pilot hole punching press 6 is sequentially fed into the washer 10 and the dryer 12 by the tab coil feeder 8 so that the tab coil 2 is washed and dried.

Next, the tab coil 2 is fed into the cylinder roll printer 16 via the pitch roll in-feeding unit 14 so that design patterns are printed and tabs are formed at the same positions on the tab coil 2 at the same pitches in the design pattern-printing step and the tab-forming step (ST-200).

Here, the guide pins 142 attached to the tab coil pitch roll 147, the guide

pins of the pitch back-up roll 143, and the pilot pins 163 of the print cylinder roll 162 are inserted into the pilot holes 201 formed in the tab coil 2 and into the pilot insertion holes (not shown) formed in the back-up roll 164, thus preventing the generation of accumulated tolerance of the pattern position to be printed on the tab coil 2 due to the variation of the length of the tab coil 2 by the thermal expansion and contraction.

Alternately, the pilot insertion holes (not shown) may be formed in the outer circumference of the cylinder roll printer 162 and the pilot pins (not shown) may be formed on the back-up roll 164 located close to the lower surface of the cylinder roll printer 162, thus allowing the tab coil 2 to be transferred and simultaneously the design patterns to be printed on the tab coil 2 (ST-300 and ST- 400).

The tab coil 2 fed into the cylinder roll printer 16 at uniform pitches is dried by the driers provided inside the cylinder roll printer 16, and then transferred to a next step (ST-500).

Under the condition that the uniform pitches of the tab coil 2 are maintained by the pitch roll out-feeding unit 18, the tab coil 2 is wound on the re-coiler 22.

Thereby, the printing step is completed (ST-600).

After the printing step, the tab coil 2 is provided to the uncoiler of the conversion press for forming tabs. The tab coil 2 is unwound from the uncoiler (ST-700), and then tabs are formed by the conversion press.

Since the pilot holes 201 are already formed in the tab coil 2 using the pilot hole punching press 6 prior to the printing step, a pilot hole-punching step is omitted. The pitches in the tab coil 2 in the design pattern-printing step and the tab-forming step are maintained to be the same by coupling the pilot holes 201 with

the pilot pins of a set of mold dies of the conversion press (ST-800).

Industrial Applicability As apparent from the above description, the present invention provides a method and an apparatus for manufacturing a pre-printed and post-formed type design tab end using pilot holes, in which pilot holes are formed in a tab coil by a pilot hole punching press at the same pitches as by a conversion press prior to a printing step, and then design patterns are printed on the tab coil and tabs are formed on the tab coil, thus preventing the actual positions of the patterns printed on the tab coil from deviating from ideal and desired positions.

Particularly, in order to compensate accumulated tolerance of the pattern position to be printed on the tab coil generated by the pilot holes and the pilot pins, pilot holes and pilot pins are individually formed on a cylinder roll printer and a back-up roll located close to the cylinder roll printer in addition to pitch roll in- feeding and out-feeding units. Accordingly, it is possible to precisely transfer the tab coil and simultaneously print designated design patterns on the transferring tab coil.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.