Conveyors: power-driven – Conveying system having plural power-driven conveying sections – Recycling load in a closed path
Reexamination Certificate
2001-09-27
2003-11-04
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveying system having plural power-driven conveying sections
Recycling load in a closed path
C198S343100
Reexamination Certificate
active
06640962
ABSTRACT:
FIELD OF THE INVENTION
The device of the present invention relates generally to transfer systems and the like. More specifically, it relates to automated workstations for use in production facilities.
BACKGROUND OF THE INVENTION
Many present day industries use a conveyor type transfer system, whether it is belt drive or chain drive, to transfer pallets from one point to another. Conveyor systems must either run continuously or must be stopped at each workstation. Stopping at each workstation leads to excessive wear and tear on the drivetrain of the conveyor. If the conveyor does not stop at each workstation, then there must be a device that provides for a positive stop so that work may be performed on the product. A second stop, or cue stop, is also required so that the parts that are advancing toward the workstation do not collide with the part being worked on.
The disadvantages to this type of system are obvious. First, there is the problem of belt wear. If the belt is moving and the pallet is stationary, the movement of the belt will cause wear on both the pallet and the belt. The alternate solution, stopping the conveyor at each workstation, merely switches the wear problem from the belt to the drivetrain of the conveyor.
Another problem with prior devices of this type is excessive transfer time. Conveyors generally require a three to four second cycle time for a pallet that is being worked on to move on to the next workstation and the next pallet to move into the first pallet's workstation. The device of the present invention reduces the transfer time to about one second because all of the pallets move simultaneously, thus eliminating the need for pallets to be cued up behind each workstation and thereby increasing productivity.
Prior devices also take up more space. Manufacturing space is prime real estate. Thus, bulky prior transfer devices have high overhead requirements. For example, a standard conveyor device requires a pallet at each workstation and space for a pallet in cue. The device of the present invention allows a workstation over each pallet. Thus, the device of the present invention requires only one-half the space of prior transfer systems. The device of the present invention also eliminates the need for complicated systems for transferring pallets from conveyor to conveyor, thus conserving even more space.
An additional problem is that prior devices require several drive motors to accomplish the same thing that the device of the present invention can accomplish with just a single motor. For example, a conveyor system that must turn a complete square will need at least four power sources, one for each side of the square. This inventor is also aware of several conveyor systems which require an additional operation to transfer around corners. The device of the present invention can be powered by a single cylinder, a single servo motor, or even by hand.
Prior devices are also handicapped by their requirements for multiple mechanically actuated stops around the conveyor belt for workstations and for cues before the workstation. All of the stops require some form of automation, including complicated sensors for detecting the location of pallets and complex software to keep track of all the operations occurring throughout the conveyor system. The device of the present invention virtually eliminates the requirements for sensors and software because the device is “intertwined” in such a way that each pallet moves in lockstep with every other pallet.
A further limitation of prior devices is that they require a “pick and place” operation for precision manufacturing. The device of the present invention reduces the time necessary for precision machining by providing bushings within each fixture. Thus, each workstation operation can be completed on the fixture itself, reducing the amount of time necessary for procedures and eliminating the need for pick and place machining operations. This inventor is not aware of any prior devices that accommodate this requirement with the simplicity of the device of the present invention.
The device of the present invention also offers extraordinary versatility. For example, the device may be adapted to use different size square pallets or even rectangular pallets. The device may also be assembled in virtually any configuration having 90-degree angles. For example, a manufacturer may need a very simple series of operations and employ a simple square transfer system. A manufacturer could build any design required for the particular article of manufacturing or necessitated by the floorplan of the building. The device of the present invention may also be adapted for use in clean room environments.
Lastly, prior devices require extensive maintenance. The conveyor belts and multiple drives associated with conveyor operations are difficult to maintain. In contrast, the device of the present invention allows easy access to workstations.
SUMMARY OF THE INVENTION
It is therefore a principal object of the interlocking transfer system of the present invention to provide a new, useful and uncomplicated assembly that transports fixtures or pallets to a workstation. It is also an object of the present invention to improve upon the speed and efficiency of prior conveyor devices. It is yet a further object to provide a transfer system that is capable of either manual or automated procedures. It is still another object or the present invention to eliminate the need for transfer space due to traffic control and end to end cross transfer. It is also an object of the present invention to provide an efficient way to transfer pallets around 90 degree corners. It is a further object of the present invention to provide a system that allows for pallet swapping ability and offers multiple configurations to fit floor space. It is another object of the present invention to provide a device that can be purchased for significantly less than comparable systems and that occupies less than half the space of comparable systems. It is yet another object of the present invention to provide a low-maintenance device that is suitable for use in a clean room.
The device of the present invention obtains these objects. It can be configured in any number of setups depending on both production necessities and floor space. The device of the present invention consists generally of a workstation with four or more sides positioned at 90-degree angles from one another, a cam lift assembly on each of the sides and means for moving the pallets horizontally. The cam lift assembly is actuated by a reciprocating cylinder which operates to lift and lower the pallets. While the pallets are lifted, they are also advanced horizontally using either an external reciprocating cylinder, a motor, or by hand. The device of the present invention provides a combination of high efficiency and low transfer rate. The present invention eliminates the need for lift and locate devices, transfer space due to traffic control and end-to-end cross transfers. The device of the present invention also provides for interchangeable fixtures. Further, the device of the present invention may be advanced by either manual or automatic means. Lastly, the purchase price is less than comparable conveyor systems. The foregoing and other features of the device of the present invention will be further apparent from the detailed description that follows.
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Ellis Christopher P.
Heino Joseph S.
Ridley Richard
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