Conveyors: power-driven – Conveyor section – Pusher conveyor and separate load support surface
Reexamination Certificate
2000-05-10
2002-07-09
Pape, Joseph D. (Department: 3612)
Conveyors: power-driven
Conveyor section
Pusher conveyor and separate load support surface
C198S746000, C198S468110
Reexamination Certificate
active
06415910
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a forward feed device for conveyor tables with a drive element that can be moved to and fro, which moves out of the table area during the forward movement and back underneath it during the return movement.
There are a variety of prior art drive elements that are capable of pushing an item to be conveyed forwards in a particular direction and of dipping below the conveyor surface during the return stroke. Conveyor surfaces of this type will be referred to in this context as conveyor tables. They may be designed as roller or ball conveyors, belt conveyors with spaced belts or as simple sliding surfaces. A so-called transfer conveyor between the pressing stations of a press line can be regarded as an example although this is not, however, intended to restrict the scope of the validity of this invention. In this instance, sheet metal parts usually have to be moved into a given position for alignment against stops.
SUMMARY OF THE INVENTION
This invention will relate to a forward feed device that will, for example, allow a sheet metal plate to be pressed against stops as part of the aligning operation in front of a press. In more general terms, the intention of the forward feed device according to the invention is to allow an object of basically any form to be pressed against stops as part of the aligning operation in front of a work station of any type.
The invention is based on the task of providing a forward feed device of the said type which is relatively easy to manufacture and exhibits low inertia, therefore allowing it to be moved to and fro quickly.
To solve this task, the forward feed device of the invention is characterized in that the drive element comprises a pivotable latch that can be moved upwards out of the table area during the forward movement, of which the end that leads and can be raised during the forward feed movement is supported, via a link with two pivoting ends, by a friction block that trails behind during the forward feed movement and the return movement, and that is slowed down by friction against a stationary surface.
The friction of the friction block against the stationary surface causes the latch to be raised above the table area during the forward feed movement, and lowered below the table area during the return movement, because when the forward feed device moves in relation to the base, the friction block always tries to trail behind.
In connection with outlining the task of the invention it has already been pointed out that one of the aims of the invention is to ensure that the forward feed device exhibits low inertia so that it can be moved to and fro quickly. This goal is achieved by the fact that only the pivotable latch need be moved to and fro in connection with a suitable tension member, whilst the drive for the tension member can be stationary, with the pivoting action of the latch not requiring any externally supplied energy, i.e. no air cylinders, operating magnets or other similar elements as are frequently provided in prior art solutions. Another important point is that it is not necessary to run any moving power supply lines such as pneumatic air lines, electricity lines, etc., along with the drive element, because moving power supply lines on industrial plant are always subject to faults, can suffer wear and tear and make access to the plant more difficult.
BRIEF DESCRIPTION OF THE DRAWINGS
The friction of the friction block against the stationary surface ensures that the friction block trails behind as the forward feed device advances, and is able to raise the latch. There is a sufficient choice of suitable material combinations for this purpose. The friction block may also have a special friction lining on the side closest to the stationary surface, and a brake block that extends elastically from the friction block may also be provided. It may also be expedient to make the friction block from a relatively heavy material with a high inertia, whose surface closest to the stationary surfaces, insofar as the friction block rests on the latter, is pressed firmly against the stationary surface.
DETAILED DESCRIPTION
In this context it should be pointed out that the invention is not limited to applications in which the latch is moved upwards out of a conveyor surface. On the contrary, the spatial orientation of the latch and the direction in which it operates are basically immaterial. Hence the invention can, for example, be used with a downwardly movable latch for separating plates from a stack of plates. Insofar as terms such as “up” and “down” are employed in this context, they are used in relation to one form of embodiment in which the latch is raised upwards. These terms are therefore only used to simplify the description and should not be understood as obligatory indications of direction for practical applications.
The system for controlling the movement of the latch requires absolutely no maintenance or servicing, is subject to only minimal wear and tear, and works very reliably.
The drive element is preferably inserted into a gap in a strand of an endless tension member, e.g. a toothed belt. In this case the tension member is interrupted in the vicinity of the drive element, and the interruption is bridged by a connecting element with two upwardly projecting sides between which the latch can be pivotably mounted. When raised upwards, the latch should not be supported by its pivot axis, but by a supporting surface of the connecting element, because high forces, which could deform or damage the pivot axis, often occur.
In one preferred embodiment, the end of the latch that remains at the rear during a forward movement is also connected to the connecting element via a second link with two pivoting ends, which is shorter than the first link that raises the latch. This second link allows the latch to rest against the supporting surface of the connecting element, thereby ensuring that the latch axis is not exposed to forward movement forces.
To stabilize the latch and provide further guidance, a third link with two pivoting ends is preferably disposed between the point where the first link pivots with the latch and the connecting element.
REFERENCES:
patent: 2968390 (1961-01-01), Anderson
patent: 3882792 (1975-05-01), McIntier
patent: 4170292 (1979-10-01), Lang
patent: 4514133 (1985-04-01), Vercruysse
patent: 4612861 (1986-09-01), Lidguist
patent: 4669249 (1987-06-01), Aiuola et al.
patent: 4834233 (1989-05-01), Wittwer
patent: 5699896 (1997-12-01), Spada et al.
patent: 5816381 (1998-10-01), Bungter
Coletta Lori L
Goldberg Richard M.
Pape Joseph D.
Wilfred Strothmann GmbH & Co. KG Maschinenbau und Handhabungstec
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