Conveyors – chutes – skids – guides – and ways – Rollerways – Submerging and rising
Reexamination Certificate
2001-05-07
2003-06-10
Hess, Douglas (Department: 3653)
Conveyors, chutes, skids, guides, and ways
Rollerways
Submerging and rising
C193S0350SS, C193S040000
Reexamination Certificate
active
06575286
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the conveying art, and, more particularly, to a pop-up stop to halt articles moving on a conveying system.
BACKGROUND OF THE INVENTION
Articles, such as mail trays traveling down a conveyor line need to be acted upon in a variety of different ways by various machines and processes. Trays need to be controlled, diverted, tracked or stopped for accumulation in a reliable, repeatable way. Previous designs take up excessive amounts of footprint, are expensive and mechanically intense.
In the past the problem was attempted to be solved using large mechanisms which are mechanically intense. The very nature of the designs drives the cost and the size of the mechanism up. Some of these designs use blades activated by air cylinders that “pop-up” between the conveyor rollers to stop articles on the conveyor. There are always interference, clearance and cost issues associated with these designs. One design uses a thruster type air cylinder to provide the vertical motion needed to stop a package and also to withstand substantial side loads. Another design uses plastic slides that guide a metal flag up vertically to stop a mail tray. The present design uses a smaller air cylinder.
U.S. Pat. No. 3,970,180 discloses a flat stop element having a positive latch mechanism to hold the stop in the raised position and a solenoid to release the latch. A spring return mechanism raises the stop and re-engages the latch when the solenoid is de-energized.
U.S. Pat. No. 4,397,386 discloses a stop for a conveyor which is a pin or plunger and is concerned with removing frictional resistance to retraction of the stop member. The present invention does not require this since it has no such frictional resistance to retraction.
U.S. Pat. No. 4,662,500 discloses a can conveyor stop which enters the conveyor from the side and uses a spring to bias the stop into its retracted position.
U.S. Pat. No. 4,798,282 discloses a zone conveyor which may have one of three different types of article stops. The first is a gate which is raised above the conveying plane to stop articles. The second is a notched disc which is fixed to a roller, and when it is desired to stop articles a pin is moved into one of the notches to stop the roller. A third is a belt which surrounds two adjacent drive rollers. When it is desired to stop an article, the belt is tightened around the two rollers so that they cannot rotate.
U.S. Pat. No. 5,211,276 discloses a stop which acts on a special projection of pallets moving on the conveyor. A complicated cam mechanism is used to move a stop element into the path of the projection to stop movement of the pallet.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a simple, inexpensive device which will stop articles on a conveyor in an accurate and repeatable manner.
It is another object of the present invention to provide such a device which does this less expensively than competitive devices.
A further object of the present invention is to provide such a device with a robust mechanical design and robust control arrangement.
Still another object of the present invention is to provide such a device which can be retrofit onto existing conveyors.
These and other objects of the present invention are accomplished by a mechanism which is better than the prior art because it is actually integral to the conveyor and uses conveyor rollers which minimizes part count and increases reliability. This costs less, is easier to maintain, and is packaged as efficiently as possible to save space.
Articles moving in a straight line along an accumulating conveyor line need to be acted upon in different ways for diversion into different conveyor streams. This mechanism provides the repeatable registration surface for article diversion. It has a fast cycle time, minimal impact to space limitations within conveyor designs, simplicity of design, very inexpensive compared to current design, will enhance conveyor system performance and it is easy to retro-fit to existing systems.
When the stop is released the articles are touching the roller which begins to rotate as soon as there is any friction between them, so that special retraction resistance measures are not needed as in the prior art.
The present invention is an integral part of an article or mail tray conveyor and conveyor rollers which minimizes the number of different parts required and increases reliability. This is achieved by actually making a down stream idler roller become the stopping mechanism. The stopping roller pivots up to a 90 degree angle in order to stop incoming trays. The upstream roller to the pop-up roller acts as the pivot center. The linkage that allows this motion to take place is designed in such a way that it does the following: it critically constrains the pop-up idler roller, it pivots around the upstream slave roller center and is connected to an air cylinder at the other end to provide the force and motion. A bracing bar connects the linkages to one another on both sides of the conveyor. This bracing bar provides the rigidity needed for the linkage to swing through its arc. The bracing bar extends through the conveyor side wall where it is connected to the air cylinder shaft. The air cylinder is packaged in the side wall “C” channel of the conveyor. The air cylinder is a double acting type to provide fast cycle times. The packaging allows for a cleaner, more efficient and cost effective design.
The pop-up stop is used to momentarily stop articles moving along an accumulation conveyor in order to register them at a repeatable location. The stopping mechanism is an integral part of the conveyor rollers.
An existing problem is that articles moving in a straight line along an accumulating conveyor line need to be acted upon in different ways for diversion into different conveyor streams. The mechanism of the present invention provides the repeatable registration surface for article diversion.
The present invention provides a mail pop-up stop design that is more cost effective and takes up less space than prior art devices. The pop-up roller pivots to a 90 degree position.
The design is of sheet metal linkage arms, a plastic bearing, a bracing shaft, an air cylinder and a conveyor roller. This assembly is packaged neatly in the side wall of “C” channel conveyor.
Some of the benefits of the present invention are: fast cycle time, minimal impact to space limitations within conveyor designs, simplicity of design, low cost (very inexpensive compared to current designs), enhances conveyor system performance, and is easy to retro-fit into existing systems.
The design of the pop-up stop allows it to be easily retrofit into existing conveyors. It is constructed using rotating rollers which are similar to those forming the conveyor path, and actually includes two such rollers as part of the stop.
The means by which the foregoing objects and features of invention, as well as others, are achieved are pointed out in the claims forming the concluding portion of the specification. The invention, both as to its organization and manner of operation, may be further understood by reference to the following description taken in connection with the following drawings.
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Erlich Jacob N.
Hess Douglas
Kaye Harvey
Lockheed Martin Corporation
Perkins Smith & Cohen LLP
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