TEAR TAPE CHANGER
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tear tape changer for bonding a tear tape to a packaging film formed of, for example, cellophane or polypropylene, such as a tobacco packaging film or a cased article packaging film, in which the tear tape is put on the packaging film in a predetermined position and then the film and the tear tape are fed toward a heat-bonding device. More particularly, the invention is concerned with a tear tape changer wherein transfer paths each with a cutter disposed therein are formed on downstream sides of two tape reels mounted removably, and on downstream sides of the said transfer paths are disposed a backup roller for putting the tape fed from one of the transfer paths and a packaging film fed along a film feed path one upon the other and conducting the two to a downstream side, and a pressure roller for removably holding the front end of the tape fed from the other transfer path and allowing it to stand by. When the tape from one of the two transfer paths is about to be used up, the other stand-by tape is connected to the preceding tape by approaching of both pressure roller and backup roller in accordance with the result of detection of a residual tape quantity, and in this way tapes are fed to the film feed path successively in an alternate manner.
According to a conventional tear tape changer of this type, for example as disclosed in Japanese Utility Model Publication No. Hei 3-30246, a backup roller and a pressure roller, two in all, are disposed at a downstream end of each of two transfer paths, and when the tear tape changer is in operation wherein tape is fed from one of the two transfer paths to a film feed path and when a detector has detected only a small residual amount of the tape being used, the tape is cut with a cutter, while at the same time a replacement tape preset in the other transfer path is fed to the film feed path by approaching of both pressure roller and backup roller. At this time, the tape reel of the tape which has been used up is replaced with a tape-loaded reel, and in this way the tapes from the two transfer paths are fed to the film feed path successively in an alternate manner.
In such conventional tear tape changer, however, since two backup roller and pressure roller are disposed at the downstream end of each of the two transfer paths, mere arises the problem that not only the size of the tear tape changer becomes so much larger but also the structure thereof becomes complicated, thus leading to an increase of cost.
In the case where an adhesive such as a hot melt adhesive is applied beforehand to a packaging film and then tape is bonded thereto, there arises the problem that the adhesive solidifies and cannot bond the tape to a satisfactory extent because the position where the adhesive is applied to the packaging film and the tape bonding position are spaced apart from each other.
DISCLOSURE OF THE INVENTION
Accordingly, it is the object of the present invention to provide a tear tape changer wherein the tapes from two transfer paths can be connected and fed successively in an alternate manner without interference by means of one backup roller and one pressure roller and wherein an adhesive applying position to a packaging film and a tape bonding position can be set close to each other.
In order to achieve the above-mentioned object the present invention is characterized in that:
guide rollers positioned at downstream ends of two transfer paths are disposed displacedly from each other in a 5 front and rear direction orthogonal to a tape feed direction;
between the guide rollers and a pair of backup roller and pressure roller disposed downstream of the guide rollers there are disposed a route changing roller standing
10 by in a feed position where the tape from the downstream end of one transfer path is stretched around the route changing roller toward the backup roller, and a route changing roller standing by in a stand-by position where the tape from the downstream end of the other
15 transfer path is stretched around the route changing roller toward the pressure roller; and that there are provided
a drive unit which, after the tape stretched around the route changing roller standing by in the stand-by posi20 tion has been fed to a film feed path by a mutual approaching motion of the pressure roller and the backup roller, causes the said route changing roller to move to its feed position and causes the route changing roller standing by in the feed position to move to its 25 stand-by position; and
a relief means whereby only the route changing roller which moves from its feed position to its stand-by position is moved in a rear direction orthogonal to the tape feed direction so as not to interfere with the tape 30 being used.
The drive unit causes the rotative movement of the two route changing rollers, and the relief means is preferably a fixed cam with which followers connected to the route changing rollers come into abutment. 35 In the above construction, the guide rollers positioned at the downstream ends of the two transfer paths are disposed displacedly in the front and rear direction orthogonal to the tape feed direction, so even when the tapes are stretched crosswise from the guide rollers toward the two route 40 changing rollers, both are prevented from interfering with each other. After the tape stretched around the route changing roller Standing by in its stand-by position has been fed to the backup roller by an approaching motion of the pressure roller, this route changing roller is moved to its feed 45 position, while the route changing roller standing by in its feed position, which roller is in an empty state, is moved to its stand-by position while being moved backward by the relief means, whereby the route changing roller which is in an empty state returns to its stand-by position without 50 interference with the tape in use stretched onto the other route changing roller. Now the tape for replacement can be stretched onto the pressure roller.
Thus, the tapes from the transfer paths can be connected and fed successively in an alternate manner without inter55 ference by means of one backup roller and one pressure roller. Besides, the position where an adhesive is applied to the packaging film and the tape bonding position can be drawn close to each other. Therefore, in comparison with the conventional construction wherein two rollers—backup 60 roller and pressure roller—are disposed at each of the downstream ends of two transfer paths, it is possible to so much simplify the structure and decrease the cost Besides, also in the case where an adhesive such as a hot melt adhesive is applied beforehand to the packaging film for the 65 bonding of tape thereto, it is possible to effect the bonding before solidifying of the adhesive because the conveyance distance becomes shorter.