# US 6,296,726 B1 · Method and apparatus for spin welding container closures

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- Number: US 6,296,726 B1
- Document ID: US6296726B1
- Status: Granted
- Kind: B1
- Application number: 09/593,064
- Filed: 2000-06-13
- Granted: 2001-10-02
- Earliest claimed: 2000-06-13
- Assignees: Silgan Containers LLC
- Inventors: John Pencak
- Web page: https://patentgrep.com/patent/US6296726B1

## CPC

- B29C 65/7873: {using cooperating conveyor belts or cooperating conveyor chains (B29C66/83423, B29C66/83523, B29C66/83533 take precedence)}
- B29C 65/0672: {Spin welding}
- B29C 65/7841: {Holding or clamping means for handling purposes (clamping means for the purpose of applying pressure on the parts to be joined, in the area to be joined B29C66/81; work holders in general B25B; devices for holding or positioning work for welding metal B23K37/04)}
- B29C 66/12463: {being tapered}
- B29C 66/12469: {being asymmetric}
- B29C 66/1248: {Interpenetrating groove joints (interpenetrating fingered joints B29C66/139)}
- B29C 66/131: {Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area}
- B29C 66/542: {joining hollow covers or hollow bottoms to open ends of container bodies}
- B29C 66/8242: {Pneumatic or hydraulic drives (using fluid pressure directly acting on the parts to be joined B29C66/8266)}
- B29C 66/8246: {Servomechanisms, e.g. servomotors}
- B29C 66/8322: {Joining or pressing tools reciprocating along one axis}
- B29C 66/849: {Packaging machines}
- B29C 66/92431: {the pressure, the force or the mechanical power being kept constant over time (B29C66/92613 takes precedence)}
- B29C 66/929: {characterized by specific pressure, force, mechanical power or displacement values or ranges}
- B29C 66/92921: {in specific relation to time, e.g. pressure-time diagrams}
- B29C 66/93441: {the speed being non-constant over time}
- B29C 66/93451: {by controlling or regulating the rotational speed, i.e. the speed of revolution}
- B29C 66/9392: {in explicit relation to another variable, e.g. speed diagrams}
- B29C 66/961: {involving a feedback loop mechanism, e.g. comparison with a desired value}
- B65B 7/2878: {by heat-sealing}
- B29C 66/9221: {by measuring the pressure, the force or the mechanical power}
- B29C 66/932: {by measuring the speed}
- B29C 66/939: {characterised by specific speed values or ranges}
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B65B: MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING (bundling and pressing devices for cigars A24C1/44; devices for tensioning and securing binders adapted to be supported by the article or articles to be bound B25B25/00; applying closure members to bottles, jars or similar containers B67B1/00-B67B6/00; concurrent cleaning, filling and closing of bottles B67C7/00; emptying bottles, jars, cans, casks, barrels or similar containers B67C9/00)

## Abstract

Sealed synthetic resin containers are spin welded by bringing opposed, generally complimentary horizontal mating surfaces of the lid and bowl into contact under a predetermined axial pressure and rapidly accelerating rotation of the lid relative to the bowl while maintaining substantially the axial pressure to produce melting of the mating surfaces until a desired torque value is attained. Thereafter, the rotation of the lid is immediately decelerated to terminate the rotation and allow the mating surfaces to bond. Generally, the torque is monitored repeatedly during the accelerating rotation until a plateau is reached and the accelerating step is continued for at least 50 milliseconds thereafter.

## Claims

### Claim 1

The method of making sealed synthetic resin containers comprising:
(a) molding thermoplastic synthetic resin into bowls and lids therefor, said lid and bowl having substantially complimentary mating surfaces extending about the periphery thereof;
(b) filling one of said bowls with product;
(c) bringing opposed, generally horizontal mating surfaces of said lid and bowl into contact under a predetermined axial pressure while gripping said product filled bowl and lid securely;
(d) rapidly accelerating rotation of said lid relative to said bowl while maintaining substantially said axial pressure to produce melting of said mating surfaces until a desired torque value is attained; and
(e) then immediately decelerating said rotation of said lid to terminate said rotation and allow said mating surfaces to bond.

### Claim 2 (depends on 1)

The method of making sealed synthetic resin containers in accordance with claim 1 wherein said rotation is effected at a high degree of acceleration and said termination of rotation is effected at a high degree of deceleration.

### Claim 3 (depends on 1)

The method of making sealed synthetic resin containers in accordance with claim 1 wherein torque is monitored repeatedly during said step of accelerating rotation until a plateau is reached and said rotation step is continued for at least 50 milliseconds thereafter.

### Claim 4 (depends on 3)

The method of making sealed synthetic resin containers in accordance with claim 3 wherein said monitoring of said torque is effected by monitoring the power being drawn by a motor used for producing the accelerating rotation.

### Claim 5 (depends on 1)

The method of making sealed synthetic resin containers in accordance with claim 1 wherein said predetermined axial pressure is 200-500 p.s.i.

### Claim 6 (depends on 1)

The method of making sealed synthetic resin containers in accordance with claim 1 wherein said acceleration and termination of rotation is effected in less than four relative rotations of said lid relative to said bowl.

### Claim 7 (depends on 2)

The method of making sealed synthetic resin containers in accordance with claim 2 wherein said acceleration is at a rate of 35,000-250,000 rpm/sec.

### Claim 8 (depends on 2)

The method of making sealed synthetic resin containers in accordance with claim 2 wherein said deceleration is at a rate of 35,000-250,000 rpm/sec.

### Claim 9 (depends on 1)

The method of making sealed synthetic resin containers in accordance with claim 1 wherein there is included the step of directing steam onto said mating surface of said bowl prior to bringing said lid into contact therewith.

### Claim 10 (depends on 9)

The method of making sealed synthetic resin containers in accordance with claim 9 wherein nitrogen is admixed with said steam.

### Claim 11 (depends on 9)

The container spin welding apparatus in accordance with claim 9 wherein a partial vacuum is produced in sealed container.

### Claim 12

Apparatus for producing spin welded containers comprising:
(a) a holder for firmly gripping a bowl;
(b) a holder for firmly gripping a complimentary lid;
(c) means for moving said holders relative to each other to bring mating surfaces into contact;
(d) pressure applying means for applying predetermined axial pressure on the mating surfaces;
(e) acceleration and deceleration means for rapidly accelerating rotation of the holders relative to each other and for rapidly decelerating said relative rotation while maintaining substantially the predetermined axial pressure; and
(f) torque sensing means for sensing the torque generated at the mating surfaces and is operative upon said acceleration means to determine when the acceleration has reached a desired value indicative of the desired melting of the mating surfaces to effect said deceleration.

### Claim 13 (depends on 12)

The container spin welding apparatus in accordance with claim 12 wherein said torque sensing means senses the current drawn by the acceleration and deceleration means during acceleration until a plateau is reached.

### Claim 14 (depends on 12)

The container spin welding apparatus in accordance with claim 12 wherein said predetermined axial pressure is 200-500 p.s.i.

### Claim 15 (depends on 12)

The container spin welding apparatus in accordance with claim 12 wherein said acceleration and termination of rotation is effected in less than four relative rotations of the lid relative to the bowl.

### Claim 16 (depends on 12)

The container spin welding apparatus in accordance with claim 12 wherein said acceleration is at a rate of 35,000-250,000 rpm/sec, and wherein said deceleration is at a rate of 35,000-250,000 rpm/sec.

### Claim 17 (depends on 12)

The container spin welding apparatus in accordance with claim 12 wherein there is included means for directing steam onto the mating surface of the bowl prior to bringing said lid into contact therewith.

### Claim 18 (depends on 17)

The container spin welding apparatus in accordance with claim 17 wherein there is included means for admixing nitrogen with the steam.