Manufacture of plastic containers

• US 5,275,767 A
• Filed: 06/19/1991
• Issued: 01/04/1994
• Est. Priority Date: 06/19/1991
• Status: Expired due to Fees

• Current Assignee: Frank S. Micciche
• Original Assignee: Frank S. Micciche
• Inventors: Micciche, Frank S.
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): EASTLEY, BRIAN
• Application Number:
  US07/717,633
• Time in Patent Office: 930 Days
• Field of Search: 264/23, 264/248, 264/296, 264/322, 156/69, 156/73.1, 156/580.2, 156/293
• US Class Current: 264/445
• CPC Class Codes: B29C 2043/3636 ultrasonically or sonically vibrating, e.g. sonotrodes
• CPC Class Codes: B29C 2791/008 Using vibrations during moulding
• CPC Class Codes: B29C 57/00 Shaping of tube ends, e.g. flanging, belling or closing; Apparatus therefor , e.g. collapsible mandrels
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/1222 comprising at least a lapped joint-segment
• CPC Class Codes: B29C 66/1224 comprising at least a butt joint-segment
• CPC Class Codes: B29C 66/534 Joining single elements to open ends of tubular or hollow articles or to the ends of bars
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis

Abstract

A container is manufactured by placing a length of extruded thermoplastic tubing over a mandrel so that an end of the tubing extends beyond the mandrel to form an annular rim and placing a thermoplastic slug on the mandrel within the rim. An ultrasonic resonating horn is provided having a cavity adapted to receive the rim. The horn cavity has a base and an annular tapered portion formed around the base and engageable with the rim. The tubing and the resonating horn are pressed together with a relatively moderate force so that the tapered portion of the horn cavity engages the rim of the tubing and softens and folds it inwardly in such a manner that it is in alignment with the slug, the mandrel, and the base of the cavity. The mandrel and the resonating horn are then brought together with a relatively large force to squeeze the folded rim and the slug tightly together between the mandrel and the base of the cavity. Ultrasonic waves propagated from the horn into the folded rim and the slug fuse the rim and the slug together to form a watertight seal at the end of the tubing. Thereafter, a different mandrel and a different ultrasonic resonating horn are employed to fuse a stand to the sealed end of the tubing.

Claims

1. A method of forming a bottom of a container for liquids, the method comprising the steps of:

effecting a relative movement between a length of extruded thermoplastic tubing, a thermoplastic slug, and a mandrel that results in the tubing being positioned around the mandrel, the tubing having a first portion that extends to the slug, a first open end that extends beyond the slug to form an annular rim, and a second open end which is opposite the first open end and which forms a top of the container, the slug being supported by the mandrel within the rim;

providing an ultrasonic resonating horn having a cavity adapted to receive the rim, the horn cavity having a base and an annular tapered portion formed around the base and engageable with the rim;

applying a relatively moderate force to the tubing and the resonating horn to press them together so that the tapered portion of the horn cavity engages the rim of the tubing and softens and folds it inwardly in such a manner that it is in alignment with the slug, the mandrel, and the base of the cavity;

applying a relatively large force to the mandrel and the resonating horn to press them together to squeeze the folded rim and the slug tightly together between the mandrel and the base of the cavity to form the bottom of the container without deforming the first portion of the tubing; and

propagating ultrasonic waves from the horn into the folded rim and the slug to fuse the rim and the slug together and form a watertight seal at the end of the tubing.

2. A method according to claim 1 further comprising the step of providing an injection-molded stand engageable with the sealed end of the tubing for supporting the tubing in an upright position with an open end of the tubing uppermost for ingress and egress of a liquid and the sealed end lowermost for preventing leakage of liquid contained in the tubing.

3. A method according to claim 2 wherein the providing of the stand comprises the steps of:

placing an injection-molded stand in contact with the sealed end of the tubing;

inserting a mandrel into the tubing; and

propagating ultrasonic waves into the stand around the sealed end of the tubing to fuse the stand and the sealed end together.