Plastic blow molding in-mold labeling system

Details Plastic blow molding in-mold labeling system Plastic blow molding in-mold labeling system

1999-06-18

2001-02-06

Davis, Robert (Department: 1722)

Plastic article or earthenware shaping or treating: apparatus

Preform assembly means and means for bonding of plural...

Reshaping means utilizing fluid pressure directly contacting...

C264S509000, C264S543000, C425S126100, C425S522000, C425S532000, C425S540000

Reexamination Certificate

active

06183238

ABSTRACT:

TECHNICAL FIELD
This invention relates to an in-mold labeling system for use with rotary blow molding to provide an in-mold labeling operation.
BACKGROUND ART
In-mold labeling has been developed in the recent past to provide superior bonding of labels to blow molded containers. Such in-mold labeling is performed by inserting a label within an open mold prior to closing of the mold around an extruded hot plastic tube or a heated injection molded plastic preform. Subsequent mold closing and blow molding forms the hot plastic around the label to the shape of the mold and activates a heat sensitive adhesive that provides a permanent bond which is incapable of being broken by moisture or otherwise. Also, such in-mold labeling provides a smooth transition between the label and the adjacent surface of the container and further provides additional strength since the label cooperates with the container wall in resisting deformation. Such strengthening also allows the use of less plastic to blow mold the container and thereby reduces the ultimate cost to the consumer. Furthermore, when utilized with containers for carbonated beverages, the in-mold labeling reduces the flow of carbon dioxide out through the container wall over a period of time and thereby increases the shelf life.
U.S. Pat. No. 4,479,770 Slat et al., U.S. Pat. No. 4,582,474 Ziegler, U.S. Pat. No. 4,639,207 Slat et al., and U.S. Pat. No. 4,909,723 Slat et al. disclose in-mold labeling systems wherein a dispensing head of the in-mold labeling system is moved between a label supply location aligned with one or more label magazines adjacent the associated blow molding machine and a label delivery position within an adjacent open mold of the blow molding machine, and one or more label carriers on the dispensing head is moved between a retracted position and a label transfer position in order to provide a pick and place movement of the labels from the label magazines into the mold where a vacuum is drawn to secure the label to the mold before mold closing for the blow molding operation. A vacuum is also utilized by the label carrier to secure the labels for the movement from the associated label magazine to the associated mold.
In-mold labeling systems of the type described above have previously included a common mechanical drive from the blow molding machine for driving the dispensing head between the label supply and delivery locations and for also driving the label carriers between the retracted and label transfer positions. As such, the respective speeds and movements of the dispensing head and each label carrier are coupled with each other.
With relatively high speed labeling, it has been found that it is difficult to remove labels from a label magazine at a greater speed than about 65 to 70 labels per minute since such high speed operation does not allow time for air to enter behind the label as the label carrier pulls it from the label magazine. As such, more than one label can be pulled away and thereby cause problems in the in-mold labeling process.
Previously, in-mold labeling of a pair of labels to an associated pair of mold members of a mold has been performed in two ways. In one practice, a pair of rotary drive members that are spaced from each other and each rotates an associated lever that has a cam and follower connection to an associated label carrier to provide the label carrier movement between the retracted and label transfer positions. In another practice, a single rotary drive member is utilized and through a lever drives one label carrier that is connected by a gear and rack assembly to another label carrier so that both label carriers are concomitantly moved between the retracted and label transfer positions by the rotation of the one rotary drive member.
Other United States patents disclosing in-mold labeling for plastic blow molding include: U.S. Pat. No. 4,680,000 Nowicki et al.; U.S. Pat. No. 4,729,731 Hasl et al.; U.S. Pat. No. 4,801,260 Oles et al.; U.S. Pat. No. 4,808,366 Kaminski et al.; U.S. Pat. No. 4,834,641 Keyser; U.S. Pat. No. 4,861,542 Oles et al.; U.S. Pat. No. 4,880,368 Hasl et al.; U.S. Pat. No. 4,944,665 Hasl et al.; U.S. Pat. No. 4,973,241 Keyser; U.S. Pat. No. 5,044,922 Plenzler et al.; U.S. Pat. No. 5,086,937 Robinson; U.S. Pat. No. 5,169,653 Tate et al.; U.S. Pat. No. 5,192,554 Savich et al.; U.S. Pat. No. 5,275,780 Robinson; U.S. Pat. No. 5,344,305 McKillip; U.S. Pat. No. 5,350,483 Yager et al.; U.S. Pat. No. 5,383,779 Robinson; U.S. Pat. No. 5,665,404 Weber et al.; U.S. Pat. No. 5,753,278 Aguilar; and U.S. Pat. No. 5,759,593 Weber et al.
DISCLOSURE OF INVENTION
An object of the present invention is to provide an improved in-mold labeling system for use with a rotary blow molding machine including a rotary wheel having molds thereon movable between open and closed positions to perform blow molding.
In carrying out the above object, the in-mold labeling system of the invention includes at least one label magazine for storing a supply of labels at a location adjacent the rotary wheel of the blow molding machine. A dispensing head of the system includes at least one label carrier for transferring the labels from the label magazine to the open molds prior to mold closing for the blow molding. The system includes a first electrical servomotor and a first cam mechanism driven thereby to move the dispensing head between a supply location adjacent the label magazine and a delivery location between an open mold on the rotary wheel. The system also includes a second servomotor and a second cam mechanism driven thereby to move the label carrier of the dispensing head between a retracting position and a label transfer position. First and second electrical controllers of the system respectively operate the first and second servomotors. A sensor of the system senses rotation of the rotary wheel of the blow molding machine to operate the first and second controllers to separately drive the first and second servomotors such that the label carrier is moved from the retracted position to the label transfer position while the dispensing head is in the supply location to receive a label from the label magazine and is then moved back to the retracted position for movement of the dispensing head to the delivery location where the label carrier is again moved to the label transfer position to transfer the label to an adjacent open mold prior to mold closing for the blow molding.
In the preferred construction disclosed, the system includes a pair of label magazines for supplying two labels to the dispensing head upon label carrier movement from the retracted position to the label transfer position and then back to the retracted position with the dispensing head in the supply location and for subsequently simultaneously supplying the two labels to two adjacent open molds by label carrier movement from the retracted position to the label transfer position and then back to the retracted position with the dispensing head in the delivery location. The second controller operates the second servomotor faster while the dispensing head is in the delivery location than while in the supply location. More specifically, the second controller can be programmed to operate the second servomotor twice as fast in the delivery location than while in the supply location.
In the preferred construction of the in-mold labeling system, the dispensing head includes two pairs of label carriers movable in opposite directions as each other and also includes two pair of label magazines for respectively supplying two labels to each pair of the label carriers upon movement from the retracted position to the label transfer position and then back to the retracted position while the dispensing head is in the supply location and for subsequently simultaneously suppling the two labels on each pair of label carriers to two adjacent molds by movement from the retracted position to the label transfer position and then back to the retracted position while in the delivery location. The second controller operates the second servomotor faster w

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