Package making – Closing packages and filled receptacles – Package or receptacle having closure flap – e.g. – carton...
Reexamination Certificate
2000-06-29
2001-11-20
Ashley, Boyer (Department: 3724)
Package making
Closing packages and filled receptacles
Package or receptacle having closure flap, e.g., carton...
C053S376400, C053S375400, C053S378300, C083S076900, C083S431000, C083S444000, C083S112000, C083S858000, C083S946000, C493S025000, C493S056000, C493S179000, C493S183000, C493S357000
Reexamination Certificate
active
06318049
ABSTRACT:
BACKGROUND OF INVENTION
FIELD OF INVENTION
Slitter machines of the prior art are designed to complete the packing process on filled tab lock corrugated cases. The machine's in-line design initially slits the tab-locks on filled corrugated cases, positions the loose flaps for sealing, and seals the flaps with a series of hot glue guns. The case is then sealed and discharged on a compression conveyer. Many of the machines of the prior art are designed to accommodate cases of varying size and as such are quite complex.
An in-line slitting machine of the prior art is discussed in U.S. Pat. No. 4,551,964 (the '964 patent), commonly assigned to applicant and incorporated herein by reference, which eliminates the need to turn the case. The machine of the '964 patent applies pressure to the sides of the case, and exposes the tab-locks for cutting.
Filled corrugated cases are fed into the slitter portion of a slitter machine. The cases are directed into the machine, held down by rollers, and indexed onto an infeed lug chain. The rollers hold the case down, ensuring it does not jump the leading lug on the infeed lug chain. The leading lug serves as the infeed timer and controls the entry of cases into the machine.
The infeed chain then separates the cases and directs them toward the main flight chain, using rubber side-drive chains. The side-drive chains grip the case horizontally, controlling it as it advances toward the main flight chain. The side drive chain runs at the same speed as the main flight. The main flight chain includes flight lugs which lift the leading edge of the case and twist it. The case is twisted to expose the front and rear tabs to a pair slitter knife guides. The slitter knife guides incorporate a sharpened edge along their upper portion functioning as a knife. As the case passes through the knife guides, the tab locks are cut. Once through the slitter, the end flaps are then raised by an end flap lifter and directed through a flap tucker which closes the front and rear flaps, leaving the side flaps in a down position.
Once the case has passed through the flap tucker, the side flaps are lifted by flap guides. These guides ensure that the side flaps are lifted up and away from the side of the case as it exits the slitter section. This step is accomplished to avoid any binding of the flaps. As the case moves out of the slitter section, it is indexed onto a conveyor belt at the infeed of the sealer section. The case then enters a set of flap guides, which control the position of the flaps as they enter the glue applicator.
Once the case has entered the glue section, the side flaps remain upright until the glue is applied to the inside of the flap. The case is then directed forward into a compression section, which closes the two side flaps using flap guides and seals the case using a series of rollers. The cases are then discharged from the machine onto the customer's discharge conveyor.
The infeed timer uses wedge-shaped steel lugs mounted to a pair of timing chains perpendicular to product flow to ensure that the cases enter the slitter at the rate of movement of the flight chain. The lugs are moveably positioned at a distance less than the desired case length apart along the chains. The timing chains are mounted between two side-drive chains such that a case is accelerated forward against a first lug and is raised up on top of a second following lug. When the first lug passes the end of the infeed timer, the case is accelerated downstream by the side drive chains. The timer is mechanically synchronized to release one case into the slitter in time with the main flight chain, located downstream. The pair of side-drive chains operate at the same speed as the main flight chain, and have two sections of rubber lugs that propel the cases forward against the timer lugs. One problem with the timer of the prior art is the time and accuracy required to effect a changeover for a different case size. The lugs must be mechanically removed from the timing chains, a sample case positioned on the conveyor and the lugs must be repositioned for the newly desired case length. Frequent case size changeovers cause problems with lug and fastener wear, chain stretch, drive sprocket alignment and wear, leading to timing problems between the infeed section and the warping section of the machine. Another problem with the prior art is that the case may be dropped into the flight chain too early either because the side drive chain is not properly positioned or the side drive chain width is set too wide. These problems are caused by the fact that physical movement of separate elements to effectuate case size changes are required, including case width adjustment of the drive chains and advance or retard of the side drive chain.
The main flight chain transports the cases from the timer through the slitter guides, end flap lifters, and the flap tucker section. After directing the cases through these sections, the flight chain then discharges the cases from the slitter to the transfer conveyor. The flight chain is made up of two flat-top chains having, for example, 12 sets of leading and trailing flight lugs, attached thereto. The main flight chains ride on plastic tracks for minimal noise and friction. Each set of flight lugs carries and controls one case. The leading edge of a case rests on a set of leading flight lugs and is prevented from sliding off by the associated trailing flight lug. The leading flight lugs are fixed along the main flight chains at an interval less than the smallest desired case length. The trailing flight lugs are mechanically moveably connected to the main flight chains to allow positioning of the trailing flight lug further from, or closer to, the preceding flight lug to accommodate a full range of case lengths in, for example, six 1.5 inch increments. A stationary cam is located near each chain having a profile to contact the flight lugs such that the cases are lifted and twisted as they advance along the flight chain. A problem with the prior art transport chain is the time required to make a case size changeover. In order to effect a changeover, all 12 sets of lugs must be removed from the chains and reinstalled at the proper position. Frequent changeovers also lead to wear of the lugs and fastening elements. In addition, the flight chains of the prior art are relatively long and the weight of the lugs causes the chains to stretch which leads to wear, alignment and timing problems.
The tab lock slitter guides of the prior art mount two spring-loaded blades vertically on either side of the main flight chain. As the flight lugs advance up their respective cams, lifting and twisting the case, the front and rear tab-locks are exposed to the blades. The knife guides are wedged into the gaps created between the case and its side flaps as the case proceeds along the chain. As the flight lugs ride down their respective cams, the case is forced down onto the knives, thus cutting the tab-locks. Each case is held in place by a case hold-down, which is suspended from a side of the machine frame and positioned above the case. One problem with tab lock slitters of the prior art is their limited ability to accommodate the deviation in position of the tab locations. If the tabs of a certain case are too high for instance, the knife will fail to completely slit the tab causing a machine jam. An additional problem with tab lock slitters of the prior art is that there exists a limited amount of accuracy available in accommodating different case sizes. For instance, case centering is changed by physically loosening both sets of knife guides placing a case on the main flight chain and moving the guides within a prescribed distance from the case while ensuring parallelism of the guides. Improper adjustment of the guides can result in erratic tab lock slitting. The integral knife guide/blades of the prior art also pose a problem of edge sharpening and blade replacement. In order to effect a blade change or to sharpen the knife edges the guides must be remove from th
CoFrancesco Emilio N.
Raudat John L.
Reilly Jeffrey
Ashley Boyer
Cantor & Colburn LLP
Standard Knapp Inc.
LandOfFree
Slitter machine for tab lock cases does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Slitter machine for tab lock cases, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Slitter machine for tab lock cases will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2587564