Patent Application
20060119028
I. Field of the Invention
The present invention relates generally to packaging machinery and, more particularly, to a transport mechanism for handling and manipulating flat objects such as carton blanks through an intermediate processing step such as the application of adhesive to end tabs prior to die and plunger carton formation. Specifically, the invention enables a blank to be picked from a magazine, run past an adhesive application system at a fixed, constant distance and speed, and deposited in place for a carton forming step using a single mechanism.
II. Related Art
Packaging container cartons are typically folded and formed from flat carton blanks that are forced into a die using a plunger. Prior to forming, adhesive is applied to the tabs of the flat carton blanks where they are desired to adhere in the folded, formed state. This has previously been accomplished using a plurality of consecutive mechanisms. The first mechanism includes a device for vacuum-picking carton blanks off a stack or magazine and depositing them in front of the head of a shuttle system. The shuttle system is then used to move the blanks past one or more glue heads which is activated using an optical sensor which contains a built-in programmable timing system which includes a timed delay and a timed pattern for applying glue to the carton blank as it goes past. The shuttle system then deposits the blank in position for formation in a die using a conventional die and plunger system and retracts to receive the next blank. While such a combined system is satisfactory, it is quite expensive and includes an open, exposed mechanism. There has long been a need to replace such a multi-mechanism system with a single mechanism system with the ability to pick a carton blank from a source of supply, run it past an adhesive applicator at the desired distance and speed and deposit it in place for carton formation.
By means of the present invention, there is provided a reciprocating transport system for processing flat objects fed from a magazine stack, or other type pick and place supply. The system includes a pivoting transport carriage that has the ability to acquire and manipulate flat objects of interest past a processing device at a speed and distance from that processing device as designed by the drive system. The transport system of the invention thereafter releases the objects at a location and disposition according to a next processing step. The transport system of the invention is characterized by the coordination of a powered rotating cam and a pair of spaced flat plate cams. A drive motor powers the rotary cam which, through a linkage system, actuates a crank lever which provides reciprocating motion and speed control of the transport carriage. The transport carriage actuated by the rotary cam is driven through the pair of flat cams positioned one per side of the machine. The flat cam profile provides the means of controlling the position of the flat object from the pick location at the magazine supply or other supply through a work zone and past a processing device such as a glue application system and finally releasing the object in position for the next process step. The rotary cam is designed to operate at a constant speed and the cam and lever combination enables not only precise pick and release locations but precise control of speed and distance as the flat object traverses a processing zone.
The embodiment of the detailed description is directed to a reciprocating or cycling carton blank transport system in which the flat objects are carton blanks and in which the carton blank transport system is a device integral to a carton forming machine. The system is designed to operate in conjunction with a carton blank supply magazine, adhesive application system, which may apply hot melt or other glues to designated portions of a carton blank such as end tabs, and an ensuing carton forming operation which uses a plunger and carton forming die system in a manner well known to those in the art to produce a three-dimensional carton. In this embodiment, the rotating cam, crank lever system and flat plate cams cooperate in a manner such that the pivotally mounted carton blank transport carriage actuated by the rotary cam with followers is driven along the profile of the flat plate cams during a processing part of the operation. The carton blank picked up from the pick location at the magazine stack supply proceeds through the adhesive application zone to accurate placement at a carton forming die set.
The blank processing part of the cycle is associated with the rotary cam proceeding through approximately one-half revolution. In the second half of each revolution, the carton blank transport carriage is caused to return along the profile of the flat plate cams causing the carriage to retrace and return to the pick location to retrieve another blank for the next cycle.
An important aspect of the invention pertains to the combination of the pivotal mount of the blank transport carriage, peripheral profile shape of the rotary drive cam, construction of the crank lever and linkage system and the profile of the flat plate cams. These all combine, not only to precisely position the transport carriage to pick up and discharge a flat carton blank or other flat object with precision, but also, in a preferred embodiment, to provide a process or adhesive application zone in which the carton blank or other flat plate object passes glue guns or other devices at a constant angle, constant distance and constant speed. In one embodiment, this zone is about 330 mm in length. It will be appreciated that the cam and lever combination can be designed to modify the profile of the transport process if desired.
In the drawings, wherein like numerals depict like parts throughout the same:
a and 3b are rear perspective views illustrating certain details of a drive system in accordance with the invention with parts removed and showing the system in two positions; and
a-4c are schematic representations of one side and the drive mechanism illustrating the operation of the carton blank transport system.
The following detailed description pertains to a carton bank transport system for manipulating carton blanks from a stock supply through adhesive application and placement at a carton forming die. The apparatus is an integral part of carton forming machinery and the steps followed are part of the overall process of carton formation from blanks. It will be appreciated, however, that the concept can be used in other situations in which flat objects need to be acquired, manipulated past a processing device at a desired distance and speed profile and placed in position for the next step using a single mechanism.
The transport system cooperates with one or more integral carton blank or flat object processing devices. A plurality of spaced adhesive application devices are illustrated generally at 50, 52 and 54. These will be explained in further detail below in conjunction with other figures.
The carriage side structures are of identical opposed construction such that only one need be described in detail, the other being identical but opposite hand. These are best shown in the progressive schematic drawings of
The drive mechanism which operates the reciprocating transport mechanism of the invention is best illustrated in the progressive schematic views of
The
The optical sensor 118, integral timing device and known speed of the system enable an application pattern to be programmed for each type of carton blank to be processed. When the edge of a carton is encountered by the optical sensing device, the timer then times out a delay and thereafter controls application of adhesive according to a further timed pattern which corresponds to the blank size, style and speed of the system. Because the reciprocating transport system of the invention enables the carton blank to pass the adhesive application devices at a constant speed and distance, this assures uniform application of adhesive in the proper places on the blank prior to carton formation.
In operation, the magazine or other source of supply of a stack of blanks is adjusted for the size of the blank in relation to the transport carriage. It should be noted that the center line of the carton blank is the center line of the base of the carton and this should be aligned with the center line of the arm member 60 when the transport carriage is in the fully retracted position ready to acquire or pick a blank. The system can be provided with an adjustable scale to adjust the location of the center line for each size blank being run. One such system (not shown) uses a hand crank and gear box, which can be adjusted and then locked in place for a particular run.
With the object transport carriage in the fully retracted position, suction cups on the carriage are then utilized to grab a blank from the magazine with the rotary cam activated and rotating clockwise to operate the system. Continued rotation of the rotary cam causes the carriage system to follow the profile of the flat plate cam openings at a speed as determined by the profile of the rotary cam. The combination of the levers and cam profiles is determined such that an acquired carton blank passes beneath the glue guns at a given distance and speed providing a constant velocity, constant distance work zone which, in one embodiment, is about 330 mm in length. This provides a constant distance and constant timing between the glue guns and the carton blank so that a uniform layer of adhesive may be applied. Control is achieved by using the optical sensor 118 to sense the passage of the edge of a carton blank which initiates the timer which coordinates the spraying of glue from the gun with the particular blank size and shape. This portion of the cycle is illustrated in
The rotary cam continues to rotate causing the carriage to continue along the profile of the spaced flat plate cams to the position shown in
In one machine, the cycle time was about 1.7 seconds or about 35 cycles per minute for an adhesive-applying operation. Other operations may employ different cam profiles and achieve different cycle rates. Of course, such other operations may have no need to transport the carton blank at constant speed and position.
Of course, between delivery of glue-applied carton blanks to the forming die location, the forming die is operated to shape the carton which is then discharged and moved on in the process.
This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
