Patent Application
20130299309
The invention relates to methods and apparatus for conveying articles, and particularly for changing the orientation of articles being conveyed.
Plastic blow molded containers are ejected from a blow molding machine and are conveyed to a processing station for de-flashing or trimming. Non-round containers may be oriented in a first direction when conveyed away from the blow molding machine but may need to be re-oriented substantially 180° when delivered to the processing station.
Apparatus for rotating articles 90° are known, and two such apparatus could be utilized serially to rotate the containers 180° before delivery to the processing station. However, separate rotations of 90° take up valuable floor space and that floor space may not be available. Furthermore, not all non-round container shapes are compatible with the known apparatus.
Thus there is a need for a conveyor apparatus that can re-orient articles being conveyed, such as non-round blow molded containers, 180° in one step and with greater flexibility with respect to the shape of the article capable of being re-oriented.
The present invention relates to a conveyor apparatus that is capable of re-orienting an article 180° from a first orientation to a second orientation in one step and with greater flexibility with respect to the shape of the article being re-oriented.
A conveyor apparatus in accordance with the present invention revolves the article about a stationary vertical axis to rotate the article a first angular displacement from the first orientation, and then pivotally rotates the article a second angular displacement in addition to the first angular displacement before fully discharging the article onto the second conveyor. The combined angular displacements enable a greater change in article orientation than that provided by revolving the article alone.
A preferred embodiment of a conveyor apparatus in accordance with the present invention has a body rotatable in a direction about a vertical axis. The body is preferably formed as an annular disk having one or more pockets or slots, each slot extending inwardly into the body to a closed end of the slot.
Each slot is defined at least partially by a leading edge and a trailing edge, the leading and trailing edges extending from the closed end of the slot and radially spaced apart from one another. The leading edge is shorter than the trailing edge so that a radially outer portion of the slot is open and unobstructed by the body from the trailing edge in the circumferential direction.
The disk is placed over the downstream end of a first conveyor and an upstream end of a second conveyor, the conveyors located such that the slot moves over and essentially parallel with the first conveyor to receive an article from the conveyor into the slot, and the slot moves over and is transverse to the second conveyor to discharge an article from the slot onto the second conveyor. The second conveyor engages the article and generates a torque on the article urging the article to pivot around the leading edge of the slot as the article is discharged out of the slot.
The conveyor apparatus of the present invention enables an article to be reoriented with a greater angular displacement with respect its line of travel than that provided by revolving the article alone, saving valuable floor space. Since the articles are received into slots conformed to closely receive the article, the conveyer apparatus can be adapted with greater flexibility to the shape of the article being conveyed.
Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing sheets illustrating embodiments of the invention.
The illustrated conveyor apparatus 10 is used in conveying empty, non-round plastic containers from a blow molding machine (not shown) to a de-flashing station (not shown). The upstream conveyor 12 receives the containers in a first orientation from the blow molding machine and the downstream conveyor 16 delivers the containers in a second orientation rotated 180° from the first orientation to the de-flashing station.
The upstream conveyor 12 includes a horizontal conveyor belt that carries the containers in the travel direction 14. Railings or guide fences 24a, 24b extend along the sides of the conveyor belt 22. The downstream conveyor 16 includes a horizontal conveyor belt 26 co-planar with the conveyor belt 22 that carries the containers in the travel direction 18. Railings or guide fences 28a, 28b extend along the sides of the conveyor belt 26.
The rotary transfer apparatus 20 includes a horizontal disk or star wheel 30, a horizontal floor 32, and a guide assembly 34. The star wheel 30 is driven by a motor 36 to rotate about a vertical axis of rotation 38 in the direction of rotation indicated by the arrow 40. The star wheel 30 is spaced above and overlays end portions of the conveyor belts 22, 26 to receive containers from the conveyor belt 22 and discharge containers to the belt 26. The floor 32 is essentially even with the conveyor belts 22, 26 and extends between the belts to support containers moving from the belt 22 to the belt 26. The guide assembly 34 includes a set of vertically spaced flat lead-in surfaces 42 connected to curved cam surfaces 44 that extend in the direction of rotation around the star wheel 30 from the upstream conveyor 14 to the downstream conveyor 16.
The slot 50 is bounded by a trailing edge 58 extending along the longitudinal axis 56 from one end of the inner edge 54 to the periphery 48, and a leading edge 60 extending along the axis 56 from the other end of the inner edge 54 to the outer periphery 48. The leading edge 60 is spaced from the trailing edge 58 and extends a substantially shorter distance than the trailing edge 58, the leading edge 60 dividing the trailing edge 58 into an inner edge portion 62 facing the leading edge 60 and an outer edge portion 64 extending from the inner edge portion 62 to the disk periphery 48. The leading edge 60 and the inner edge portion 62 are on opposite sides of the slot axis 56 and define an inner slot portion 66 bounded on opposite sides by the edges 60, 62, with the remainder of the slot 50 being an outer slot portion 68 bounded by the outer edge portion 64. The outer slot portion 68 is unobstructed by the body 46 from the outer edge portion 64 in the direction generally perpendicular to the slot axis 56.
The leading edge 60 intersects the disk periphery 48 at a relatively sharp acute angle, the intersection defining a corner 70 that is rounded to assist in the discharge of a container from the slot 50 as will be explained in greater detail below. The corner 72 defined by the intersection of the trailing edge 58 and the disk periphery 48 is also rounded to assist in the intake of a container into the slot 50 as will be explained in greater detail below.
Referring back to
In the illustrated embodiment the directions of travel 14, are parallel with one another. The star wheel 30 rotates about 90° to move a slot 50 from the upstream conveyor 12 to the downstream conveyor 16. In other embodiments of the conveyor apparatus 10 the directions of travel 14, 16 can be non-parallel or transverse to one another and the star wheel 30 may rotate more or less than about 90° to move a slot from the upstream conveyor to the downstream conveyor.
The lead-in surfaces 42 extend from the rail or fence 24a to the star wheel 30. The surfaces 42 are vertically spaced preferably along substantially the full height of a container to resist tipping of containers moving against the surfaces 42.
The curved cam surfaces 44 extend from the lead-in surfaces to the rail or fence 28a. The cam surfaces 44 are also vertically spaced preferably along substantially the full height of a container to resist tipping of containers moving against the surfaces 44. The cam surfaces 44 have a curvature whose center is offset from the axis of rotation 38 so that the distance from the cam surfaces 44 to the axis 38 decreases in the direction of rotation.
Operation of the conveyor apparatus 10 is discussed next.
When the container C is received into the slot 50a, the flat leading edge 60 engages against a flat surface of the container C and the trailing edge 58 extends along a side of the container C to urge the container C to revolve around the axis of rotation 38. Preferably the trailing edge 58 engages the side of the container C on opposite sides of the container's center of gravity so that the container remains against the trailing edge 58 as the container moves with the star wheel 30.
In the position shown in
The corner 70 is rounded to facilitate rotation of the container C out of the slot 50a, and the trailing edge 58 is slightly concave to provide clearance relief as the container rotates about 90° and out of the slot 50a. Preferably the leading edge 60 stops well short of the center of gravity of the container C to maximize the torque or moment urging the container C to pivot and rotate about the corner 70. In the illustrated embodiment the trailing edge 58 extends longitudinally the full length of the container C while the leading edge 60 extends longitudinally substantially less than half the distance of the edge 58; preferably the leading edge 60 terminates well short of pulling along even with the center of gravity of the container C.
The fence or guide rails 28a, 28b are spaced relatively wide apart adjacent the star wheel 30 to accommodate the rotation of the container C out of the slot 50a and onto the conveyor belt 26. The guide rails 28a, 28b taper inwardly towards each other as they extend in the direction of travel 18 away from the star wheel 30 to correct for any under-rotation or over-rotation of the container C out of the slot 50a and assures proper orientation of the container as it travels downstream on the conveyor belt 26 to the de-flashing station.
Each slot 50 of the star wheel 30 shown in
In
The illustrated embodiments have the axis of rotation of the body 45 spaced from the slot(s) 50. In alternative embodiments of the invention, the axis of rotation of the body 46 can pass through the slot 50, that is, the axis of revolution of a container moving from the first conveyor to the second conveyor can pass through the container itself.
The diameter of the star wheel 30 and the shape and number of the slots 50 can be different in other embodiments of the conveyor apparatus 10 to accommodate receiving and pivotally rotating containers of other shapes, sizes, and materials.
Different types of conveyors known in the conveying art can be used in alternative embodiments of the invention, and the upstream and downstream conveyers can be a different type of conveyors from the other.
In yet other possible embodiments the upstream conveyor 14 and the downstream conveyor 16 can be portions of a single conveyor whose belt is sufficiently wide to accommodate rotation of the container by the star wheel without the container leaving the belt. In such embodiments the fences or railings can be located over the conveyor belt to align the containers for entry into the star wheel and for discharge from the star wheel.
While this disclosure has illustrated and described preferred embodiments of the invention, it is understood that this is capable of modification, and that the invention is not limited to the precise details set forth, but includes such changes and alterations as fall within the purview of the following claims.
