Patent Application
20070085260
This invention relates generally to carton packaging machines and more particularly to segment wheel assemblies of such machines for picking single carton blanks from a magazine and delivering the carton blanks to a conveyor.
It is well known in carton packaging machines to utilize segment wheel assemblies to pick single carton blanks from a magazine of back-to-back blanks and position the blanks on a conveyor. The conveyor generally then transports the carton blanks to in a single file end-to-end relationship to an area of the packaging machine where they are folded around or packed with articles such as, for example, beverage cans. U.S. Pat. No. 6,497,084 of Janen, which is owned by the assignee of the present invention, discloses a carton blank transport apparatus that includes a traditional segment wheel assembly and conveyor for the aforementioned use, and this patent is hereby incorporated fully by reference.
A pair of pick arms 16 and 17 are mounted on a pick arm shaft 18 disposed above the segment wheels. The pick arms extend downwardly between the segment wheels and are provided at their lower ends with suction cups 19 and 21. Of course, associated suction lines, side plates, bearings, sprockets, and gears are associated with the segment wheel assembly 11 to operate the assembly as described below. Such associated machinery is well known in the art and thus need not be described in detail here.
The suction cup grabs the end blank of the stack and, as the pick arm begins to articulate back, pulls the blank to the right in
While prior art segment wheel assemblies have proven reasonably successful, they nevertheless have been plagued with various problems and shortcomings inherent in their designs. The most serious of these, perhaps, is the fact the pick arm must be highly curved and convoluted as shown in
Accordingly, a need exist for an improved segment wheel assembly in which carton blanks are picked from a stack at or near their top edges rather than nearer their middle portions. More generally, a need exists for a segment wheel assembly wherein suction cups of the pick arm assembly can be positioned to engage blanks at any desired location. A further need exists for a segment wheel assembly with a simpler, more space efficient, and less convoluted pick arm configuration. It is to the provision of a segment wheel assembly that addresses these and other needs that the present invention is primarily directed.
Briefly described, the present invention, in one preferred embodiment thereof, is an improved segment wheel assembly that addresses the problems and shortcomings of the prior art. The segment wheel assembly comprises a pair of spaced apart segment wheels in the shape of horizontally aligned cylinders closed at one end. Each segment wheel or cylinder has a separate shaft secured to and projecting from its closed end and the shafts are rotatably journaled in appropriate bearings on respective side plates of the assembly. Thus, unlike the prior art, there is no segment wheel shaft that extends across the entire assembly. Instead, the space between the facing ends of the segment wheels is open and free of any obstruction. Each segment wheel cylinder is machined with an open slot along one side and the slots of each segment wheel also are aligned with each other. The drive train of the assembly rotates each of the separated aligned segment wheels in unison so that the slots always align and rotate with each other.
A pair of pick arms are mounted on an articulating shaft above the segment wheels. The pick arms extend downwardly into the open and unobstructed space between the facing ends of the segment wheels and are provided on their lower end portions with suction cups for grabbing carton blanks from a magazine as described above. Since the space between the segment wheels is open and unobstructed, the pick arms can be straight or substantially straight, or at least less convoluted as needed, because there is no shaft in the space to be avoided as the arms articulate. More importantly, however, the suction cups can be positioned on the pick arms so that they engage cartons in the magazine at or near the top edges of the cartons or at any more desirable location. Thus, the problems caused in the prior art from bowing of cartons during the selection process is eliminated. Further, since the pick arms are simpler, the space between the segment wheels can be narrower than in the prior art, which, in combination with the more desirable selection of carton blanks from their top edges, allows the assembly to function with narrower carton blanks than the prior art.
These and other features, objects, and advantages of the spaced segment wheel assembly of this invention will become more apparent upon review of the detailed description set forth below, when taken in conjunction with the accompanying drawing figures, which are briefly described as follows.
Similarly, a second segment wheel 46, which is a mirror image of the first segment wheel 44, has a rectangular cutout 48 and is rotatably mounted to the end plate 43 by means of a shaft 51 that is journaled in and extends through a bearing assembly 53. A sprocket 56 is mounted to the end of the shaft 51 on the outside of end plate 43 so that rotation of the sprocket 56 causes the second segment wheel 46 likewise to rotate. The cylindrical segment wheels are mounted in opposed horizontally aligned and spaced apart relationship with respect to each other. Most significantly, since the shafts 49 and 51 are fixed to the closed ends of the segment wheels 44 and 46 respectively, there is no shaft that extends across the entire width of the assembly as in the prior art. Thus, the space between the opposed segment wheels 44 and 46 in the center of the assembly is completely open and unobstructed.
A drive shaft 57 extends between the end plates 42 and 43 at the bottom of the assembly and its ends are rotatably journaled in and extend through respective bearing assemblies 58 and 59. A sprocket 61 is secured to the left hand end, in
Nip rollers 67, which preferably are made of a rubberized or otherwise high friction material, are mounted beneath the segment wheels 44 and 47 and may engage the segment wheels. The nip rollers may be separately rotatable at a desirable speed or may rotate with the segment wheels. Conveyor chains 69 are shown between the nip rollers. The conveyor chains 69 are part of a conveyor assembly that extends downstream of the segment wheel assembly and to which carton blanks are fed by the segment wheel assembly. The conveyor assembly itself is traditional and not part of the present invention and thus it is not shown or described in detail here. However, reference is made to U.S. Pat. No. 6,497,084 incorporated by reference above, which discloses a typical packaging machine conveyor assembly. The conveyor chains 69 may include dogs 70, which, as is known in the art, align and space single carton blanks on the conveyor assembly as the blanks are conveyed from the segment wheel assembly 41 to downstream areas of the packaging machine where they are packed with articles such as, for instance, beverage cans.
A pick arm assembly 71 is mounted between end plates 42 and 43 above the spaced segment wheels 44 and 46. The pick arm assembly comprises a pick arm shaft 72 that is rotatably journaled in and extends through bearing assemblies 73 and 74 on the end plates. A first pick arm 76 and a second pick arm 77 are secured to the pick arm shaft 72 at its mid section. As described in more detail below, the pick arms 76 and 77 extend downwardly into the unobstructed space between the segment wheels 44 and 46 as shown. A first suction cup assembly 78 is mounted, preferably adjustably, to the first pick arm 76 and is positioned between the segment wheels. A second suction cup assembly 79 is mounted, again preferably adjustably, to the second pick arm 77 and likewise is positioned between the segment wheels, all as shown in
A crank assembly 81 operatively links the segment wheels to the pick arm assembly and thus to the pick arms 76 and 77. More specifically, a crank wheel 83 is operatively secured to the end of the pick arm shaft 72 on the outside of end plate 42. A corresponding crank wheel 82 is secured to the end of the segment wheel shaft 49 outboard of the sprocket 54 so that the crank wheel 82 rotates with the sprocket 54 and thus with the segment wheels 44 and 46. The crank wheel 83 is provided with an off-center crank lug 87 that projects outwardly from the crank wheel. Likewise, the crank wheel 82 is provided with an off-center crank lug 86. A crank arm 84 links and is rotatably coupled to the crank lugs 86 and 87.
In operation, the crank lugs are strategically located on their respective crank wheels so that rotation of the segment wheels 44 and 46 and, consequently, rotation of the crank wheel 82 causes the pick arm crank wheel 83, and thus the pick arm shaft 72, to rotate back and forth through only a portion of a full arc. This, in turn, causes the pick arms 76 and 77 and their suction cup assemblies 78 and 79 to move or oscillate back and forth in a direction generally normal to the page in
With the just described arrangement, it will be seen that when the drive shaft is rotated, the segment wheels rotate in unison while the pick arms and suction cups oscillate back and forth in the unobstructed space between the segment wheels. The nip rollers also rotate against the segment wheels and, separately, the conveyor chains are driven so that their top flight moves downstream away from the segment wheel assembly 41.
Operation of the segment wheel assembly of this invention will now be described with reference to segment wheel 44 and pick arm 76 shown in
To accomplish the above purpose, segment wheel 44 with its rectangular cutout 47 is rotated in a counterclockwise direction as indicated by arrow 89. At the same time, nip roller 67 rotates or is rotated in a clockwise direction as indicated by arrow 91. As the segment wheel 44 and nip roller 67 rotate, pick arm 76 and its suction cup assembly are oscillated by pick arm shaft 72 in a back and forth direction, as indicated by arrows 92. The timing of the rotation and oscillation, as determined by the configuration of the crank assembly, is such that the suction cup moves toward the stack 88 of carton blanks as the rectangular cutout 47 rotates around toward the blanks. The suction cup engages and grabs the end-most blank of the stack 88 and begins to oscillate back to the right in
Shortly after the carton blank engages the segment wheel 44, the rectangular cutout 47 of the segment wheel 44 rotates past the upper edge portion of the blank. The upper edge portion of the blank, aided by the moving suction cup, falls and/or is pulled into the rectangular cutout at the leading edge thereof. As the segment wheel continues to rotate, the trailing edge of the rectangular cutout engages the upper edge portion of the carton blank on the back side of the blank, the suction cup disengages and moves out of the way to the right, and the trailing edge of the cutout begins to urge the upper edge portion of the carton blank downwardly toward the bottom of the segment wheel and toward the nip roller 91. When the upper edge portion of the carton blank engages the nip roller 91, it is captured by the rubberized nip roller, which ejects the carton blank to the right, as indicated at 93 and 98 in
It will thus be seen that the segment wheel assembly of this invention provides numerous advantages and improvements over prior art segment wheel assemblies of the type shown in
The invention has been described herein in terms of preferred embodiments and methodologies considered by the inventors to be the best mode of carrying out the invention. It will be apparent to those of skill in the art, however, that various additions, deletions, and modifications might be made to the illustrated embodiments within the scope of the invention. For instance, as mentioned above, the pick arm or pick arm assembly can be shaped other than as shown or can comprise multiple components if desired to provide for appropriate range of adjustment of the suction cup assembly and other purposes. Further, while cylindrical segment wheels with rectangular cutouts are considered preferable, segment wheels of other shapes also might be substituted. For example, it may be possible to substitute traditional disc-shaped segment wheels on separate shafts with an unobstructed space between the segment wheels. Indeed segment wheels of many configurations might be substituted for the preferred cylindrical segment wheels, and such will be equivalent to the segment wheels of the preferred embodiments. Finally, while the particular drive train shown in the preferred embodiment also is preferred, other drive train configurations certainly are possible. These and other modifications to the illustrated and preferred embodiments may be made by skilled artisans without departing from the spirit and scope of the invention as set forth in the claims.
