Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-11-10
2001-05-29
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S285000, C156S580200
Reexamination Certificate
active
06238503
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic welding apparatus including an ultrasonic horn for holding an engagement portion of a plastic fastener such as a plastic stud or a plastic clip, the plastic fastener having a flange to be welded onto a workpiece and the engagement portion extending from the flange, wherein the flange of the plastic fastener held by the ultrasonic horn is brought into contact with workpiece and ultrasonic energy is applied to the ultrasonic horn so that the plastic fastener is ultrasonically welded onto the workpiece. The present invention further relates to an ultrasonic welding method for a plastic fastener.
It is already commonly practiced to weld, by using ultrasonic energy, a plastic fastener such as a plastic stud or a plastic clip which has a flange to be welded onto a workpiece such as a plastic panel and an engagement portion extending from the flange. One known ultrasonic welding apparatus includes an ultrasonic horn for holding the engagement portion of the plastic fastener, and means for bringing the flange of the fastener held by the ultrasonic horn into contact with the workpiece, wherein ultrasonic energy is applied to the ultrasonic horn so that the flange of the plastic fastener is welded onto the workpiece.
In a conventional ultrasonic welding apparatus, an engagement portion of the plastic fastener is manually inserted into the tip of the ultrasonic horn so that the ultrasonic horn can hold the engagement portion of the plastic fastener. Alternatively, in the case of automatic loading, the ultrasonic horn is moved to a location where the plastic fastener has been fed for loading there. However, as it is troublesome to load the fasteners one by one, such loading operations are not efficient. Particularly, for loading a plastic fastener to the ultrasonic horn, it is necessary to securely locate the engagement portion of the plastic fastener in the tip of the ultrasonic horn. In order to make manual loading quickly, it is also necessary to master such a skill. In automatic loading, the mechanism for moving the ultrasonic horn may become complex.
Therefore, it is an object of the present invention to provide an ultrasonic welding apparatus of a simple structure that allows automatic loading of a plastic fastener to an ultrasonic horn, and to provide an ultrasonic welding method with high efficiency in its operation.
SUMMARY OF THE INVENTION
To accomplish above object, according to the present invention, there is provided an ultrasonic welding apparatus including an ultrasonic horn for holding an engagement portion of a plastic fastener such as a plastic stud, the plastic fastener having a flange to be welded onto a workpiece and the engagement portion extending from the flange; and means for bringing the flange of the plastic fastener held by the ultrasonic horn into contact with the workpiece, wherein ultrasonic energy is applied to the ultrasonic horn so that the flange of the plastic fastener is ultrasonic welded onto the workpiece. The ultrasonic welding apparatus comprises: fastener feeding means for feeding a plastic fastener to load it into the ultrasonic horn; fastener receiving means for receiving the fastener of which flange is advanced first from the fastener feeding means; and moving means for moving the fastener receiving means to a position beneath the ultrasonic horn; the moving means being capable of moving the engagement portion of the fastener in the fastener receiving means to a position adjacent to a engagement portion support of the ultrasonic horn, the fastener receiving means being formed with a recess to seat the flange therein, the seating recess being adapted to be supplied with negative pressure air to vacuum-retain or tack the flange, the seating recess having a rim formed in a sloping configuration so that the flange can be positioned in the center of the seating recess.
As described above, since the seating recess of the fastener receiving means which receives the plastic fastener fed from the fastener feeding means is formed in a sloping configuration, and negative pressure air is supplied to the seating recess to vacuum-tack the flange, the flange is positioned at the center of the seating recess. Thus, the flange is very precisely and securely positioned on the fastener receiving means, so the position of the flange will never be shifted even when the fastener receiving means is moved by the moving means. As the plastic fastener can be securely and precisely positioned on the ultrasonic horn only by the movement of the fastener receiving means through the moving means, it can be automatically loaded into the ultrasonic horn.
According to the present invention, there is also provided an ultrasonic welding method including steps of holding an engagement portion of a plastic fastener such as a plastic stud or a plastic clip, the plastic fastener having a flange to be welded to a workpiece and the engagement portion extending from the flange in an ultrasonic horn; and then bringing the flange of the plastic fastener into contact with the workpiece so that the flange is ultrasonically welded onto the workpiece. The welding method comprises the steps of: feeding the plastic fastener to a fastener receiving means in a manner that the fastener is advanced with the flange leading from a fastener feeding means; seating the flange of the fastener in a seating recess of the fastener receiving means, the seating recess having a rim formed in a sloping configuration, and then, vacuum-retaining or tacking the flange of seated fastener by negative pressure air; moving the fastener receiving means to a position adjacent to the tip of ultrasonic horn; vacuum-retaining or tacking the engagement portion of the fastener held by the fastener receiving means into the ultrasonic horn so that the fastener is held by the ultrasonic horn; returning the fastener receiving means back to a fastener receiving position where the fastener is received from the fastener feeding means; ultrasonically welding the flange of the fastener onto the workpiece, while bringing the flange of the fastener held by the ultrasonic horn into contact with the workpiece; and after welding, returning the ultrasonic horn back to it's home position where it is lifted up from the workpiece; and wherein the method further includes, between the step of returning the fastener receiving means and the step of returning the ultrasonic horn, a step of feeding a next fastener in the manner that the flange thereof is advanced ahead to the fastener receiving means which has been returned back to the fastener receiving position. According to such method, not only an ultrasonic welding apparatus of a simple structure is obtained, but also the next fastener is held by the fastener receiving means during ultrasonic welding operation of previous fastener, whereby fastener feeding time in the next ultrasonic welding operation can be reduced and the operational efficiency can be increased.
According to the present invention, since the flange of the plastic stud is very precisely and securely located with a simple structure, the position of the fastener will never be shifted even when the fastener receiving means is moved by it's moving mechanism, and since the plastic fastener can be securely and precisely located in the ultrasonic horn only through the movement of the fastener receiving means, the plastic fastener can be automatically loaded into the ultrasonic horn. Furthermore, according to the present invention, since a next plastic fastener is held in the fastener receiving means during ultrasonic welding operation of previous plastic fastener, the fastener feeding time in the next operation can be reduced and therefore the operational efficiency can be increased.
REFERENCES:
patent: 5622579 (1997-04-01), Tobias
patent: 6063220 (2000-05-01), Andersson
patent: 6149755 (2000-11-01), McNichols
Emhart Inc.
Murphy Edward D.
Sells James
LandOfFree
Ultrasonic welding apparatus and ultrasonic welding method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ultrasonic welding apparatus and ultrasonic welding method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ultrasonic welding apparatus and ultrasonic welding method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2561663