Patent Publication Number: US-5894710-A

Title: Package squaring device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, generally, to apparatus and methods used in the packaging industry. More particularly, the invention relates to apparatus and methods for folding flaps of cartons traveling in a continuous stream. The invention has particular utility in folding the major flap of a six-sided carton while maintaining the relatively squared corners of the carton. 
     2. Background Information 
     The state of the art includes various devices and methods for folding flaps of cartons traveling on a continuous carton conveyor. These devices include stationary plows and rotary tuckers. U.S. Pat. No. 5,036,644, assigned to applicant&#39;s assignee, illustrates a stationary plow; and U.S. Pat. Nos. 5,456,058, 5,457,940, and 5,241,806, all assigned to applicant&#39;s assignee, illustrate rotary tuckers. 
     These devices and methods are believed to have significant limitations and shortcomings. These limitations and shortcomings are especially evident when the known art attempts to fold the major flaps found in the bottom of six-sided cartons. Although stationary plows work well for folding small flaps, they tend to skew six-sided cartons when they attempt to fold the major flap. These cartons are stored and loaded into a carton magazine in a relatively flat shape. The six-sided cartons have a tendency to skew away from a rectangular footprint and back toward their original flat shape after they have been erected on a carton conveyor. The size of the major flaps is another factor that significantly affects the skewing problem. When a carton moves longitudinally over a stationary plow designed to laterally fold the major flap, the plow produces a resultant force. The lateral component of the resultant force folds the flap. However, the longitudinal component of the resultant force pushes the flap of the carton back against the longitudinal flow of the cartons and skews the cartons. Larger flaps cause the stationary plows to induce larger longitudinal component forces, which cause a greater tendency to skew the cartons when the flap is folded. 
     Rotary flap tuckers are typically used to fold dust flaps or end flaps found on the side of the carton. These flaps are longitudinally folded either with or against the flow of the stream of cartons. However, the major flap of the six-sided cartons are folded in a direction lateral to the flow of the stream of cartons. Therefore, these rotary flap tuckers would have to be adapted to laterally fold these bottom flaps. However, these stationary rotary flap tuckers would either have to operate at a speed that exerts considerable force on the cartons and thus skews the cartons, or they would require the cartons to travel at a lower speed or with intermittent motion. 
     Applicant&#39;s invention provides a package squaring device, or flap lifter, which overcomes the limitations and shortcomings of the known art. Specifically, it acts as a moveable plow that longitudinally travels along side of the cartons and produces a gentle lateral force to fold the flaps. Therefore, the package squaring device does not create the resultant forces that tend to skew the cartons. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a flap lifter or package squaring device for folding flaps on cartons. The package squaring device generally comprises a lug, a flap tucker pivotally connected to the lug, and a cam bar slidably linked to the flap tucker. A plurality of squaring devices are attached to a flight chain or other endless conveyance mechanism, and thus form an endless flight or series of package squaring devices. Each lug contacts and stabilizes a carton traveling on a compression conveyor. When the lug travels past a first position, the cam bar is forced upward by a cam and causes the flap tucker to pivot into a generally parallel position to fold the flap of the carton. The cam bar travels off of the cam when the lug travels past a second position, allowing both the cam bar and the flap tucker to lower. 
     Significant features of the invention include the synchronized motion of a package squaring device with a carton traveling longitudinally on the continuous compression conveyor. This synchronized motion allows each package squaring device to exert a gentle lateral folding force to the flap of a carton and minimizes longitudinal component forces that tend to skew the carton. A preferred embodiment of the package squaring device includes an extension member or finger that controls and stabilizes each carton so that the corners of the carton are relatively squared as the carton undergoes longitudinal motion and when the flaps of the carton are laterally folded. 
     The features, benefits and objects of this invention will become clear to those skilled in the art by reference to the following description, claims and drawings. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a perspective view of the package squaring device of the present invention. 
     FIG. 2 is a front view of the package squaring device. 
     FIG. 3 is a top view of the package squaring device. 
     FIG. 4 is a side view of the package squaring device. 
     FIG. 5 is a cross-sectional view of the package squaring device taken along line 5--5 of FIG. 4. 
     FIG. 6 is an exploded perspective view of the package squaring device. 
     FIG. 7 is a top view of the lug of the package squaring device. 
     FIG. 8 is a front view of the lug of the package squaring device. 
     FIG. 9 is a side view of the lug of the package squaring device. 
     FIG. 10 is a rear view of the lug of the package squaring device. 
     FIG. 11 is a bottom view of the lug of the package squaring device. 
     FIG. 12 is a top view of a compression conveyor showing two endless flights of a plurality of package squaring devices engaging a continuous stream of cartons. 
     FIG. 13 is a side view of a compression conveyor showing two package squaring devices, the lower plate, and the cam. 
     FIG. 14 is a cross-sectional view taken along line 14--14 of FIG. 13. 
     FIG. 15 is a cross-sectional view taken along line 15--15 of FIG. 13. 
     FIG. 16 is a perspective view of a six-sided carton. 
     FIG. 17 is a top view of a partially-erected six-sided carton. 
     FIG. 18 is a top view of a fully-erected six-sided carton. 
     FIG. 19 is a side view of a six-sided carton whose major flap, minor flap, and tabs have not been folded. 
     FIG. 20 is a side view of a six-sided carton whose major flap has been folded. 
     FIG. 21 is a side view of a six-sided carton whose tabs have been folded. 
     FIG. 22 is a side view of a six-sided carton whose minor flap has been folded. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1-15, an example of the preferred embodiment of the present invention is illustrated and generally indicated by the reference numeral 10. FIGS. 16-18 illustrate the form and characteristics of a six-sided carton 12 of the type processed by the present invention. A fully-formed, six-sided carton 12 is illustrated in FIG. 16 and includes two side panels 14a and 14b and four end panels 16a, 16b, 16c and 16d. The side panels 14a and 14b are shown with slots 18. Each panel is separated by a joint or fold 20. These six-sided cartons 12 are stored and loaded into carton cartridges in a relatively flat shape. As shown in FIG. 17, the folds 20 in these paper board cartons 12 have a shape memory that causes the cartons 12 to tend to skew back toward its flat shape. The bottom of the cartons 12 include a major flap 22, a minor flap 24, and one or more tab flaps 26. A method or order for folding these flaps is generally shown in FIGS. 19-22. FIG. 20 shows the major flap 22 being folded over first, FIG. 21 shows one of the tab flaps 26 being folded over next to provide additional support, and FIG. 22 shows the minor flap 24 being folded over last. These flaps are typically glued together to maintain the structural shape of the carton. It is anticipated that the package squaring device 10 of the present invention could be used with other carton types, including cartons having different shapes, different sized flaps, and different orders of assembly. Although the package squaring device 10 is especially useful in folding the relatively large major flap 22 of a six-sided carton 12, it could be used to fold the tab flaps 26 and the minor flap 24 as well. However, these smaller tab flaps 26 and the minor flap 24 are adequately folded using a stationary plow without undue skewing of the carton 12. 
     The package squaring device 10 is described below first in terms of its major structural elements and then in terms of its secondary structural and/or functional elements which cooperate to form a &#34;moveable plow&#34; that folds the flaps of cartons 12 traveling within a continuous stream. As shown most clearly in FIG. 6, the package squaring device 10 has four major structural elements: a lug 30, a cam bar 32, a flap tucker 34, and a tab 36. The flap tucker 34 is pivotally connected to the lug 30 and hinges between a down position and a relatively horizontal up position. The flap tucker 34 is the element in physical contact with the major flap 22 on the carton 12 and produces the lateral folding motion of the package squaring device 10. The cam bar 32 has limited vertical motion in the cam bar cavity 38 between the lug 30 and the tab 36. The cam bar 32 is linked to the flap tucker 34 in such a manner that an upward motion in the cam bar 32 will lift the flap tucker 34 to fold a flap and a downward motion in the cam bar 32 will lower the flap tucker 34. The lug 30 is attached to an endless flight mechanism or flight chain 40a and 40b, as shown in FIGS. 12-15, which gives the package squaring device 10 a predetermined travel path. The package squaring device 10 travels over a cam 42 which lifts both the cam bar 32 and the flap tucker 34. The cam bar 32 has a downward bias which lowers the flap tucker 34 as the package squaring device 10 travels off of the cam 42. 
     As shown in the planar views of FIGS. 7-11 and the perspective views of FIGS. 1 and 6, the lug 30 of the preferred embodiment is a unitary element. The lug 30 is connected to the flight chain 40 through an upper 44a and lower 44b bracket recess, both of which contain a screw aperture 48. FIGS. 14 and 15 illustrate a method for attaching the lug 30 to the flight chain 40 using a bracket 50. The lug 30 further includes a main body 52, a shelf 54, a first leg 56a and a second leg 56b. The lug 30 has a relatively vertical front face 60 located below the shelf 54 and between the legs 56a and 56b. The legs 56a and 56b, shelf 54 and cam bar 32 are constructed and arranged to allow limited vertical motion of the cam bar 32 next to the front face 60. A first tab pin cavity 62a and a second tab pin cavity 62b are respectively located in the first leg 56a and the second leg 56b. The tab 36 has corresponding first 66a and second 66b tab pin apertures for attaching the tab 36 to the legs 56a and 56b of the lug 30 to form the cam bar cavity 38 using tab pin 70a and 70b. The shelf 54 extends forward toward the carton 12 and has cam bar apertures 72a and 72b configured and arranged to freely receive the cam bar 32 when it is in its upward position. The shelf 54 also has a forwardly extending finger 74 designed to engage the carton 12 using the slots 18. As shown best in FIG. 4, the finger 74 has an arcuate bottom surface 76 designed to create a stabilizing, downward force on the carton 12 when the finger 74 is fully inserted into a carton slot 18. As will be explained further below, the shelf 54 also has a bias pin aperture 78, and the lug 30 has two pivot pin cavities 80a and 80b. 
     As shown most clearly in FIGS. 5 and 6, the cam bar 32 of the preferred embodiment is a unitary element with a body portion 84 and two shoulders 86a and 86b. The cam bar 32 has the form of a uniformly thick plate and has rounded bottom for engaging a cam 42. As will be explained in more detail below, each shoulder 86a and 86b has a respective cam pin cavity 88a and 88b for interfacing with the flap tucker 34. The top 90 of the cam bar 32 contains a bias pin cavity 94 sized to receive a bias pin 96 and a bias spring 98. The bias pin 96 is also received within the bias pin aperture 78 in the shelf 54. The bias spring 98 surrounds the bias pin 96, fits below the shelf 54, and provides a downward bias to the cam bar 32. 
     As shown in FIGS. 1 and 6, the flap tucker 34 of the preferred embodiment is a unitary structure having a general shape of a handle. The flap tucker 34 has two substantially parallel arms 100a and 100b. Each arm has a pivot end 102a and 102b and a load end 104a and 104b. A cross member 106 is attached to each load end 104a and 104b. Each arm has a pivot pin aperture 108a and 108b located at the pivot end 102a and 102b. Pivot pins 110a and 110b are inserted through the pivot pin apertures 108a and 108b into the pivot pin cavities 80a and 80b in the lug 30. Each arm also has a cam pin slot 112a and 112b. Cam pins 114a and 114b are inserted into the cam pin cavities 82a and 82b of the lug. These cam pins 114a and 114b are slidably linked to the cam pin slots 112a and 112b in such a manner as to allow the cam bar 32 to lift the flap tucker 34 when raised and to allow the cam bar 32 to lower the flap tucker 34 when lowered. 
     FIGS. 12-15 show a plurality of package squaring devices 10 used with a compression conveyor 120. FIG. 12 shows a left and a right flight chain 40a and 40b used to transport the package squaring devices 10 for folding flaps from two sides of the carton. However, for the cartons 12 shown in FIGS. 16-22, only the right flight chain 40b is required to fold the major flap 22 of the carton 12 because the smaller minor flap 24 and tab flaps 26 could be adequately folded using stationary plows (not shown). 
     Each flight chain 40a and 40b travels around a pair of sprockets 122a and 122b and is governed by a forward chain guide 124 and a return chain guide 126. The package squaring devices 10 are supported by a lower plate 128. The cam 42 is integrally constructed with the lower plate 128 and is positioned to contact the bottom 134 of the cam bar 32. The package squaring devices 10 are guided out to contact the cartons 12 by the forward chain guide 124 and stabilize the cartons 12 by inserting finger 74 into carton slot 18. It is anticipated that other methods and devices, such as carton lugs, could be used to stabilize the cartons 12 while the major flap is folded. The cam bar 32 and the flap tucker 34 are raised when the package squaring device 10 travels over the up ramp 130 of the cam 42 and the cam bar 32 and the flap tucker 34 are lowered when the package squaring device 10 travels over the down ramp 132 of the cam 42. Thus, the flap tucker 34 folds the major flap 22 when the cam bar 32 contacts the up ramp 130, maintains this folded position for the glue to set the flap 22 in position while the cam bar 32 rides on the cam 42, and lowers the flap tucker34 away from the flap 22 when the cam bar contacts the down ramp 132. 
     The descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with the preferred embodiment or embodiments thereof, it should be understood that there may be other embodiments which fall within the scope of the invention as defined by the following claims. Where a claim is expressed as a means or step for performing a specified function it is intended that such claim be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof, including both structural equivalents and equivalent structures.