Machine and process for capping and sealing containers

A machine for attaching a seal member to a rim surrounding the open top of a container so as to close and seal the open top of the container, the seal member being formed at least in part from metal and being adapted to bond to the rim of the container when heated above a predetermined temperature, said machine comprising:

• a main conveyor on which the containers are supported with their open tops presented upwardly;
• lid applicator means located opposite the main conveyor for applying lids to the containers as the containers move on the conveyor, each lid being applied such that the seal member is interposed between the lid and the rim of one of the containers;
• means for spacing the containers at equal intervals along the conveyor;
• captivator means for gripping the sides of the containers and moving the containers past the lid applicator means, the captivator means including front and rear sprockets on each side of the main conveyor, chains passed around each set of front and rear sprockets so that a chain is on each side of the main conveyor, the chains having inner passes which are parallel to the main conveyor, captivator blocks on the chains and having faces which match the contour of the sides of the containers, means for moving the chains at the velocity of the main conveyor with the inner passes moving in the direction of the main conveyor, the means for moving the chains further synchronizing the chains such that captivator blocks on the two chains approach each other beyond the rear sprockets to close upon containers on the main conveyor and are located opposite each other when along the inner passes of the chains, so as to maintain the containers in an upright position on the main conveyor as the lid applicator means applies the lids;
• an induction coil located opposite the main conveyor after the lid applicator means and creating a magnetic field in a heating zone through which the lids and the container rims pass, the magnetic field being of sufficient intensity to heat the metal of the seal members above the prescribed temperature;
• and means for forcing the seal members against the rims of the containers as the containers pass through the heating zone, the means for forcing the seal members against the rims including a plurality of closely spaced parallel rollers which are located opposite the main conveyor in a position which enables them to exert an undulating force on the lids and seal members as the containers move past the rollers, and a flexible belt which moves at the same velocity and in the same direction as the main conveyor and rides against the rollers while bearing against the lids so that the force exerted by the rollers on the seal members is exerted through the belt and lids.

A machine for applying lids to the rims surrounding the open tops of containers and for further bonding membranes to the rims of the containers beneath the lids, the membranes being formed at least in part from metal and being adapted to bond to the rims of the containers when heated above a predetermined temperature, said machine comprising:

• a frame;
• a main conveyor on the frame;
• spacing means for releasing containers onto the main conveyor at equally spaced intervals with the open tops of the containers being positioned upwardly;
• chains on each side of the conveyor and having inner and outer passes, the inner passes being parallel to the conveyor;
• captivator blocks on the chains, the blocks having gripping surfaces which conform in configuration to the sides of the containers;
• means for moving the chains at the same velocity as the main conveyor and with inner passes moving in the same direction as the main conveyor, said means further synchronizing the chains such that the captivator blocks of the two chains as they move toward the inner passes converge and close on a container positioned on the main conveyor so that as the containers move along the inner passes of the chains, they are captured between the opposing blocks on the two chains;
• lid applicator means for applying lids to the open tops of the containers as the containers are gripped by the captivator blocks, the lids having the membranes contained therein before they are applied so that once the lids are applied, the membranes are interposed between the rims of the containers and the lids;
• an overhead belt located beyond the lid applicator means and having a lower pass which is parallel to and moves in the same direction and at the same velocity as the main conveyor, the belt being flexible and being positioned to contact the lids of the containers so that the containers are driven from beneath by the main conveyor and from above by the overhead belt;
• a plurality of closely spaced parallel rollers located behind and backing the belt in the direction transverse to the direction of movement, the rollers exerting a downwardly directed force on the belt, which force is transmitted through the lids, the force on the membranes being of an undulating nature due to the movement of the container and lid beneath the rollers;
• and an induction coil positioned to create a magnetic field in a heating zone located immediately below the rollers, so that as the containers pass through the heating zone the membranes are heated, the magnetic field being of sufficient intensity to heat the membranes above the prescribed temperature, whereby the membranes bond to the rims of the containers as a result of the heat and force.

A process for heat sealing a metal foil membrane to the rim surrounding the open top of a container, the membrane being capable of bonding to the rim when raised to a prescribed temperature, said process comprising:

• placing the membrane over the rim of the container such that the membrane extends across and completely covers the open top;
• placing a flexible lid over the membrane and engaging it with the container rim, the lid having a downwardly directed flange thereon which extends past the rim of the container and prevents the rim for distorting;
• thereafter passing the membrane through a magnetic field which undergoes rapid reversals of polarity, the magnetic field being of sufficient intensity to elevate the temperature of the membrane to at least said prescribed temperature;
• exerting an undulating force on the lid while the membrane is heated in the magnetic field with the force being directed such that it compresses the membrane between the lid and the container rim, the undulating force being a succession of relatively high forces applied simultaneously to the lid in narrow areas which move over the lid from one end to the other end of the lid in the direction in which the membrane passes through the magnetic field with the forces being of sufficient intensity to be transmitted through the lid to the membrane as an undulating force applied to the membrane, the width of each area being substantially less than the dimension of the lid in the direction of advance through the magnetic field;
• thereafter cooling the membrane;
• and applying a substantially constant force to the lid as the membrane cools with the substantially constant force being directed such that the membrane is compressed between lid and rim, whereby the membrane bonds to the rim.

A machine for attaching a seal member to a rim surrounding the open top of a container, the seal member being formed at least in part from metal and being adapted to bond to the rim of the container when heated above a prescribed temperature, said machine comprisng:

• conveyor means for supporting the containers with the seal members being on the container rims, but initially not bonded to the rims, and for moving the containers such that their rims and the seal members on them pass through a heating zone;
• an induction coil located at the heating zone and being capable of heating the seal members on those container rims which pass through the heating zone above the prescribed temperature;
• and means for applying a ripple-like force to the seal members while they are in the heating zone, the ripple-like force being directed toward the container rims so as to press the seal members against the rims while the seal members are above the prescribed temperature, the ripple-like force as to each seal member constituting a succession of closely spaced relatively high force applications applied simultaneously and continuously to the seal member while the seal member is in the heating zone with each force application being applied to the seal member in a narrow area, the width of which is substantially less than the dimension of the seal member in the direction of its advance through the heating zone, so that the force applications move over the seal member in the direction which the container is advanced by the conveyor means, whereby the seal member is bonded firmly to the container rim.

A machine for moving a succession of containers while a downwardly directed force is applied successively to each container above its bottom wall, each container having relatively low column strength and ordinarily being incapable of adequately withstanding the downwardly directed force when supported solely on its bottom wall, each container further having a generally peripheral rib intermediate its top and bottom ends with the portion of the container located above the rib being ordinarily capable of withstanding the downwardly directed force, said machine comprising:

• an underlying conveyor on which the containers are supported in a row with their bottom walls against the underlying conveyor;
• a rear sprocket on each side of the underlying conveyor;
• a front sprocket aligned with and located beyond each rear sprocket;
• chains passed around each set of front and rear sprockets so that a separate chain is on each side of the underlying conveyor, the chains having inner passes which are parallel to each other and to the row of containers;
• captivator blocks on the chains and being of fixed and determined configuration and at their ends having arcuate grooves, the surfaces of which match the configuration of the peripheral ribs on the sides of the containers, the grooves being located at substantially the same elevation above the underlying conveyor as the peripheral ribs and having the same contour as the ribs in both the horizontal and vertical directions;
• means for moving the chains at the same velocity and with their inner passes moving in the same direction as the underlying conveyor, the means for moving the chains further synchronizing the chains such that individual captivator blocks on the two chains, after passing beyond the rear sprockets, approach and close upon each other to capture containers on the underlying conveyor with each container being captured between a different pair of captivator blocks, whereby the containers are moved along with the opposed captivator blocks, the configuration of the grooves and their positions with respect to the conveyor when along the inner passes being such that the containers are positively and snugly captured between opposed captivator blocks and are prevented from moving horizontally and also vertically with respect to the blocks;
• means for applying a downwardly directed force on each container while it is captured at its peripheral rib between opposed captivator blocks;
• backing means for preventing the captivator blocks from moving laterally away from the containers while along the inner passes of the chains;
• and means for providing support in the vertical direction for the captivator blocks in the region of the downwardly applied force, whereby the containers are at least partially supported by the captivator blocks as the downwardly applied force is exerted.