Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2002-11-20
2004-06-15
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S073100, C156S350000, C156S580100, C156S580200
Reexamination Certificate
active
06749703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for welding a reinforcing tape formed of a synthetic resin to a portion to which the separable bottom stop of a slide fastener chain is to be attached over the core portion of a fastener tape and a main tape portion by ultrasonic heating.
2. Description of the Related Art
A space portion (a tool lacking portion) for attaching an upper stopper and a separable bottom stop is intermittently formed in a fastener chain for a slide fastener having the separable bottom stop. The separable bottom stop is attached to the space portion. Before the separable bottom stop is attached, a reinforcing tape piece formed of a synthetic resin is usually bonded to the separable bottom stop attachment portion of the fastener chain, thereby giving a reinforcement.
The reinforcing tape piece is bonded in such a configuration as to hold opposed tape side edges in the space portion of the fastener chain, and a core cord is woven into each of the opposed side edges of the fastener chain and they are therefore thick. When the whole reinforcing tape piece is simultaneously bonded to a thick portion and a flat portion by pressure, wrinkles and air bubbles to cause a separation remain. Furthermore, the bonding configuration of the reinforcing tape piece is apt to be broken. In order to solve the problem, the reinforcing tape piece is bonded and integrated in two stages as described in JP-B-62-54001 and JP-B-63-40085, for example.
In JP-B-62-54001, for example, a reinforcing tape piece is provided orthogonally to the space portion of a fastener chain for each transfer stop period of each fastener chain, the upper and lower edges of the reinforcing tape piece are bent and the reinforcing piece is held from the inside and outside of the space portion. A core cord portion held by the reinforcing tape piece and a tape portion in the vicinity thereof are then pressurized and heated from the inside and outside to bond a part of the reinforcing tape piece to the core cord portion, and subsequently, the reinforcing tape piece provided adjacently to the bonding region and the non-bonding region of the tape portion are pressurized and heated from the inside and outside to completely bond and integrate both of them.
In JP-B-63-40085, moreover, a reinforcing tape piece having a constant dimension which is formed of a thermoplastic synthetic resin is caused to abut across the opposed edges of left and right fastener tapes from both upper and lower sides of a reinforcing tape attachment portion in the space portion of a slide fastener chain. The reinforcing tape piece is interposed by pressure between an ultrasonic horn and an anvil. The ultrasonic horn includes a straight concave groove in a portion corresponding to the core cords of the left and right fastener tapes and a cutting blade on the outer end of the core cord. The anvil includes a straight concave groove in a portion corresponding to the core cord and a cutting blade on the outer end of the core cord in the same manner. Then, an ultrasonic processing is carried out and the reinforcing tape piece is welded to the outer periphery of the core cords of the left and right fastener tapes and a tape portion in the vicinity thereof, and at the same time, the reinforcing tape piece provided between the opposed core cords is cut out and the residual portion of the reinforcing tape piece is then welded to the both faces of each of the left and right fastener tapes by pressurization and heating.
On the other hand, for example, JP-B-2-35661 and JP-A-63-315223 have disclosed the control method for welding, which utilizes an ultrasonic vibration in which the temperature of a horn is detected to control the amplitude of the ultrasonic vibration of the horn. In the control method, control is carried out such that a temperature detecting element, for example, a thermistor is attached to a presser tool or a receiving portion to detect a temperature, and the amplitude of the ultrasonic vibration is increased if the temperature is low and the amplitude is reduced if the temperature is high. Moreover, as disclosed in JP-A-62-140823 and JP-A-5-299480, for example, the temperature of an ultrasonic horn including a heating device such as a heater is detected and the heating device is controlled to maintain the temperature of the horn to be constant.
According to each of the bonding (welding) techniques for the reinforcing tape piece disclosed in JP-B-62-54001 and JP-B-63-40085, the core cord portion of a fastener tape and a tape portion in the vicinity thereof is are welded to be held by a reinforcing tape piece in a first stage and the residual non-welding region of the reinforcing tape piece is welded to the fastener tape in a second stage so that integration is carried out in two stages. In JP-B-62-54001, development has been carried out on the assumption that the reinforcing tape piece is bonded to the space portion of the fastener chain through an adhesive in the two stages, and the bonding (welding) can be carried out by heating and welding using a heater if a thermoplastic synthetic resin material is used for the reinforcing tape piece. On the other hand, in JP-B-63-40085, ultrasonic welding means is employed in a first stage and heating and welding means using an ordinary heater is employed in a second stage.
As described above, it is necessary to strictly control a heating temperature and a processing time for the welding using the heater. If either of them is lessened, a bonding failure is caused. If either of them is excessive, the reinforcing tape piece enters the fastener tape in a fusing state. Consequently, the fastener tape is caused to be fragile and excessively rigid so that it might be bent or damaged easily. In addition, the welding using heater heating takes a longer time for the processing as compared with general ultrasonic welding. As disclosed in JP-B-63-40085, for example, in the case in which a welding step using the heater heating is to be carried out after the ultrasonic welding, a difference is made on the processing time. If the heating temperature of the heater is increased to match the difference in the processing time with an ultrasonic welding time in order to prevent a separation from being caused by a bonding failure, excessive heating is generally apt to be caused so that a welding portion becomes rigid and fragile. In the case in which the heating is carried out by the heater, furthermore, an air bubble is easily generated between a core cord portion and a main tape portion.
On the other hand, in the case in which a reinforcing tape piece is to be bonded to the space portion of a fastener tape of this kind, the holding configuration of the reinforcing tape piece is to be usually arranged uniformly by molding as well as welding in order to decide the configuration of the core cord portion. On the other hand, it is sufficient that the bonding of the reinforcing tape piece to the main tape portion of the fastener tape is simply carried out without changing a surface configuration thereof as long as a bonding strength is maintained. In the welding to be carried out by the ultrasonic heating under the proper conditions, only a welded surface is fused and bonded by internal heating. Consequently, a processed surface is finished finely without a deformation.
If the core cord portion of the fastener tape and the main tape portion are to be welded at the same time by using a single ultrasonic horn and a single anvil as disclosed in JP-A-5-299480, an ultrasonic oscillation is carried out with the same amplitude in an equal time for the core cord portion of the fastener tape and the main tape portion during the welding. On the other hand, it is desirable that the pressing force of the molded surfaces of the ultrasonic horn and the anvil for the core cord portion of the fastener tape at time of the ultrasonic vibration should be smaller than the pressing force of the molded surfaces of the ultrasonic horn and the anvil for the main tape portion of
Iwashita Keisuke
Maeda Hideji
Matsumura Satoshi
Sells James
YKK Corporation
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