Ultrasonic welding device and method of producing disposable diaper using same

Patent metadata

Field	Value
Publication number	US-9358159-B2
Application number	US-201414893667-A
Country	US
Kind code	B2
Filing date	Jun 13, 2014
Priority date	Jun 14, 2013
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

The displacement mechanism includes: an urging mechanism that urges an anvil roller toward an ultrasonic horn in such a manner that output surfaces and a welding surface move closer in the normal direction thereof; and a pressed member that has guide surfaces against which the outer surface of the anvil roller, positioned within non-welding areas, are pressed by an urging force of the urging mechanism, the pressed member being fixed to a sheet holding roller in a state where a pressed surface is disposed within the width-direction range of a slit. In response to the movement of the anvil roller from a welding area to the non-welding areas, the guide surfaces of the pressed member guide the anvil roller in a direction in which the output surfaces and the welding surface move away from each other.

First claim

The invention claimed is:

1. An ultrasonic welding device for ultrasonically welding an object to be welded, comprising:
a holding member that holds an object to be welded;
a pair of welding tools having an ultrasonic horn that has an output surface that applies ultrasonic vibration to the object to be welded, and an anvil having a welding surface over which the object to be welded is welded between the output surface of the ultrasonic horn and the anvil, the pair of welding tools being configured such that a moving welding tool that is one of the pair of welding tools can move, with respect to the holding member, over a welding area at which the output surface or the welding surface of the moving welding tool overlaps, in a plan view, the object to be welded that is held by the holding member, and over which the object to be welded is welded between the moving welding tool and a counterpart welding tool that is the other of the pair of welding tools, and a non-welding area that is spaced from the welding area in a plan view; and
a displacement mechanism that displaces the moving welding tool with respect to the counterpart welding tool, in such a manner that the output surface and the welding surface approach each other in the welding area, and the output surface and the welding surface move away from each other in the non-welding area,
wherein an end section of the counterpart welding tool including the output surface or the welding surface is branched, in a direction perpendicular to a movement direction of the moving welding tool, by a slit that extends in the movement direction, and has a pair of end faces positioned on both sides of the slit and functioning as the output surface or the welding surface,
the displacement mechanism includes an urging mechanism that urges the moving welding tool toward the counterpart welding tool, in such a manner that the output surface and the welding surface move closer in the normal direction thereof, and a pressed member that has a pressed surface against which an outer surface of the moving welding tool, positioned within the non-welding area, is pressed by an urging force of the urging mechanism, the pressed member being fixed to the holding member in a state where the pressed surface is disposed within a width-direction range of the slit, and
at least one of the pressed surface of the pressed member and the outer surface of the moving welding tool functions as a guide surface which, in response to the movement of the moving welding tool from the welding area to the non-welding area, guides the moving welding tool in a direction in which the output surface and the welding surface move away from each other.

2. The ultrasonic welding device according to claim 1 ,
wherein the guide surface has a shape that allows guiding the moving welding tool in the direction in which the output surface and the welding surface move away from each other in the normal direction thereof, against the urging force of the urging mechanism.

3. The ultrasonic welding device according to claim 2 ,
wherein the holding member has a pressed member mounting section that allows mounting the pressed member at a plurality of mounting positions that are set at different positions in the movement direction of the moving welding tool.

4. The ultrasonic welding device according to claim 1 ,
wherein the non-welding area is set at a position that is spaced from the output surface or the welding surface of the counterpart welding tool in the movement direction of the moving welding tool, and
the guide surface has a shape that allows guiding the moving welding tool in the direction in which the output surface and the welding surface move away from each other in the movement direction of the moving welding tool.

5. The ultrasonic welding device according to claim 1 ,
wherein the pressed member and the moving welding tool positioned within the non-welding area engage each other in such a manner as to allow the movement of the moving welding tool to the welding area, and restrict the movement of the moving welding tool in a direction perpendicular to the movement direction and to an urging direction by the urging mechanism.

6. The ultrasonic welding device according to claim 5 ,
wherein the moving welding tool is provided with a roller body having an outer surface that can come into rolling contact with the pressed member, and a pair of protrusions protruding outwardly from the roller body and welding the object to be welded between the pair of end faces of the counterpart welding tool and the pair of protrusions; and
the pressed member has an inserted section that is inserted between the pair of protrusions of the moving welding tool positioned within the non-welding area.

7. The ultrasonic welding device according to claim 1 ,
wherein the ultrasonic welding device has two of the guide surfaces at respective positions on both sides of the welding area in the movement direction of the moving welding tool, in order to guide the moving welding tool in the direction in which the output surface and the welding surface move away from each other.

8. The ultrasonic welding device according to claim 1 ,
wherein the ultrasonic horn is the counterpart welding tool having an input-side end section that has an input surface that receives ultrasonic vibration, and an output-side end section having a pair of output surfaces that output ultrasonic vibration at respective positions on both sides of the slit,
the distance between the input surface of the ultrasonic horn and each of the output surfaces of the ultrasonic horn is set to a distance corresponding to a half-wavelength of ultrasonic vibration that is input to the input surface, and
the slit is formed over a range extending from a position corresponding to a node of ultrasonic vibration, or from a position that is closer to the output surfaces than the position corresponding to the node of ultrasonic vibration is, up to the end face of the output-side end section.

9. A method of producing a disposable diaper using the ultrasonic welding device according to claim 1 , the disposable diaper having a front abdominal section disposed on the abdomen of a wearer, a rear dorsal section disposed on the buttocks of the wearer, and a crotch section that extends from the front abdominal section, passing between the legs of the wearer, up to the rear dorsal section,
the method comprising:
a preparation step of preparing a continuous body in which constituent elements each constituted by connecting the front abdominal section and the rear dorsal section via the crotch section in a longitudinal direction are continuous in a transversal direction;
a fold-in-half step of folding in half the continuous body in the longitudinal direction;
a welding step of moving the moving welding tool over the welding area and the non-welding area and inputting ultrasonic vibration to the ultrasonic horn, to simultaneously weld two sites of an overlap portion in which a portion corresponding to a side edge portion of the front abdominal section and a portion corresponding to a side edge portion of the rear dorsal section are overlapped each other, in the continuous body, between a pair of end faces of the counterpart welding tool and an output surface or a welding surface of the moving welding tool; and
a cutting step of cutting the continuous body between two weld sections formed in the welding step.

Assignees

• Zuiko Corp

Inventors

• Fujita Yukihiko
• Nakamura Hideyuki

Classifications

• B29C66/8161

  said pressing elements being supported or backed-up by springs or by resilient material · CPC title

• B29C66/8221

  Scissor or lever mechanisms, i.e. involving a pivot point · CPC title

• B29C66/1122

  Single lap to lap joints, i.e. overlap joints (B29C66/45, B29C66/472, B29C66/52272 take precedence) · CPC title

• B29C66/0326

  Cutting, e.g. by using waterjets, or perforating (using heat B29C66/0346) · CPC title

• B29C65/747

  using other than mechanical means · CPC title