Material or article handling – Horizontally swinging load support
Reexamination Certificate
2000-06-05
2002-05-28
Ellis, Christopher P. (Department: 3652)
Material or article handling
Horizontally swinging load support
C414S802000, C414S744200, C414S744500, C414S744600, C901S015000
Reexamination Certificate
active
06394740
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device and method for transferring material from one location to another, and in particular to a device for loading a pallet with material from a conveyer and unloading a pallet.
BACKGROUND OF THE INVENTION
At the end of most production lines, the manufactured good or work piece is often packaged in a box or container. If many produced items are to be shipped to the same location, they are often placed on pallets as a means of standardizing material handling. For the purposes of this disclosure, the term “palletizing” includes placing a shipping container onto a pallet and also placing a manufactured good into a shipping container. “Material to be transferred” refers to the items to be moved, such as from the end of the production line to the pallet. In addition, once a pallet is loaded and delivered, it must be unloaded. In this disclosure, “depalletizing” includes removing boxes from the pallet or removing material from a shipping container.
Currently, there are three major types of systems used for palletizing goods from an assembly line or conveyer belt: manually assisted, conventional unitizing, and robotic-based. Each system is useful and cost-effective depending on a number of factors, including: the speed of the assembly line, the complexity of the movement required to place the material onto the pallet or into a box, the flexibility and adaptability of the particular system in conforming to different loading or unloading requirements, and the uniformity of the goods to be placed onto the pallet.
In a manually assisted system, humans transfer the material from the conveyer belt and place it on the pallet. While this system is good for a slow moving conveyer belt, it is not practical for more rapid assembly lines, or if the item is particularly awkward or heavy. Further, repetitive movement injuries may be caused by repeated lifting, compounding the already high cost of labor.
Conventional unitizing systems are fully automated and are designed to handle either low or high line rates. In this method, boxes from the production line are collected to form a single layer to be dropped onto the pallet through the use of a stripper plate. Typically, this system is used with a single pallet.
Finally, robotic-based systems come in two varieties: gantry systems and pedestal systems. Both of these systems usually handle multiple line inputs and are able to load more than one pallet at a time. These systems usually include servo motors and other sensors to be able to change, in mid-line production, the box or container size by the use of controller software. In this way, they are considered “flexible.”
The gantry robotic-based system offers a low footprint-to-pallet ratio as most of its components ride along a track above the pallets to be stacked, thus creating more space on the workroom floor. In the pedestal robotic-based system, a loading arm typically sits on a pedestal and is capable of loading multiple pallets around it, or service multiple input lines. Both the robotic system and the conventional unitizing system are capable of great accuracy in placement of the boxes on the pallet. A drawback to the robotic-based gantry and pedestal systems is that as the overall production rate increases, at some point the equipment will be forced to move at very high speeds, becoming impractical, costly and possibly dangerous. It should be noted that both the manual and robotic systems can be employed to unload a pallet as well.
Given these choices, a gap exists for a mid-level producer of goods who does not want to invest the large amount of capital for a robotic-based or other automated system, or is producing at a level unsuitable for manual loading. For this mid-level producer, many of the boxes to be palletized will be of the same size and will be placed in the same location on a daily basis. In this case, there is no need for an expensive robotic-based system or automated system that is flexible or adaptable to varying conditions, or has a high-degree of accuracy. What is needed is a relatively inexpensive material handling device which is simple yet automated to avoid or minimize the need for manual labor, and which does not provide costly features that are extraneous.
With the foregoing in mind, there have been attempts to solve the deficiencies of prior palletizing systems. Of particular note, U.S. Pat. No. 3,995,745, issued to Chambers, discloses a unit for transferring an article from one workstation to another. Referring to
FIGS. 1 and 2
thereof, and the specification at column 2, the unit includes a radially reciprocating arm for carrying the work piece at its end. Camming means are provided for reciprocating the arm at selected points in a circular sweeping movement. The camming means includes a cam plate having an endless cam track in the form of a groove. A cam follower is received in the cam track. The cam follower is coupled to the arm and thus rotates with the table and is free to move radially with the arm. The cam plate is stationary with respect to the table. Thus, relative movement between the table and cam plate causes the cam follower to progress along the cam track and thereby move the arm radially. The cam track controls the distance and direction of movement of the arm by way of the cam follower. The Chambers patent does not provide, however, a device that is capable of transferring material to more than one location. Chambers is limited to moving goods from one position to another single position. Thus, what Chambers teaches is not useful for addressing the placement of items in a variety of locations, such as what is required for palletizing.
Also of note is U.S. Pat. No. 4,260,319, issued to Motoda et al. The Motoda patent discloses a simple end position control robot, which isolates the position control apparatus from the weight control apparatus, the two being mechanically associated. Although the Motoda patent does not disclose a cam track per se, the two apparatus are controlled in the XY direction by guide rails. U.S. Pat. No. 4,451,196, issued to Harada et al., discloses a transfer apparatus, including a cam follower for transmitting the swing displacements of the driving arms to the driven arms, a hydraulically controlled actuator for moving the arms, and suction cups for securing the work piece for transfer. U.S. Pat. No. 5,085,556, issued to Ohtomi, discloses a simple industrial robot apparatus comprising an extendable arm for palletizing and depalletizing loads onto or from a pallet. The Ohtomi patent also discloses a robot body or frame on which a vertically moveable arm is movably secured.
The above referenced patents do not provide a simple, economical and yet flexible system capable of palletizing and depalletizing material for a mid-level producer of goods. Most notably, the above patents describe robotic-systems that provide a level of flexibility that exceeds the need of such a mid-level producer. Thus, a need persists for further improvements in a material handling device.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a material handling device which comprises a frame, a plate supported by the frame having at least two cam tracks, a working arm with a first end connected to the frame and a second end remote from the frame, a cam follower coupled to the working arm selectively engageable with each of the at least two cam tracks, a switching element for selectively switching the cam follower into engagement with a selected one of the at least two cam tracks, and an actuator coupled to the working arm for moving the cam follower along the selected one of the two cam tracks, wherein the movement of the cam follower causes movement of the second end of the working arm along a predetermined path corresponding to the selected one of the at least two cam tracks. The cam tracks provided in the plate determine the position of the remote end of the working arm. Thus, once the positions are known where the manufactured items or boxes are t
Derby Stephen J.
Lyons Bill R.
Bower Kenneth W
Distributed Robotics LLC
Ellis Christopher P.
Lerner David Littenberg Krumholz & Mentlik LLP
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