Transfer device and a conveyor fitted with such a device

Details Transfer device and a conveyor fitted with such a device Transfer device and a conveyor fitted with such a device

1998-12-22

2001-04-24

Olszewski, Robert P. (Department: 3652)

Conveyors: power-driven

Conveyor arrangement for selecting among plural sources or...

By loading or unloading section at selected one of a...

C198S468100

Reexamination Certificate

active

06220421

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a transfer device and to a conveyor fitted with such a device.
In these conveyors used for the transportation of three-dimension objects such as parcels, pushers working in a direction different from that of the conveying direction have been used most often in a linear section of the conveyor, in order to extract the said objects from the conveying direction towards an external zone, for instance towards another, perpendicular, conveyor.
DESCRIPTION OF THE PRIOR ART
Generally, these pushers are arranged on one side of the conveyor, opposite the zone towards which the said objects must be sent, which becomes cumbersome transversally and is often unacceptable.
It is thus quite common that the pushers protrude, sometimes rather significantly, outside the conveyor, onto this transversal side.
Moreover, the actuators of these pushers are generally designed to reverse the pusher's motion upon completion of each stroke, i.e. once the object has been pushed entirely and upon completion of the pusher's retraction with respect to the conveyor.
In both cases, this motion reversion calls for additional pieces of equipment (such as stops and object sensors) in order to stop the motion in ‘forward’ direction, to respect a fixed point and to initiate the motion in ‘return’ direction.
Then, the fixed point is reached with little accuracy so that the halting position of the objects is not controlled efficiently.
In this context, let us mention the document DE-U-86 07 794 which describes a pusher designed for directing parcels carried by a first conveyor towards a second conveyor.
The pusher is articulated round a fixed pin located on the first conveyor's side, perpendicular to the conveying direction.
Thus, each object displaced from the first to the second conveyor, undergoes a rotation motion by co-operating with a pusher's end roller.
The document FR-A-1 687 777 describes a dispenser comprising a bowl feeder connected to a track for the supply of parts, whereas three pushers move perpendicular to the track on a crossbeam, without pivoting round a pin.
The document DD-A-30 935 describes a device for separating pressed parts on a circular press. Pushing plates are used to move the parts.
The document GB-A-733 204 describes a conveying system in which a carriage, moving perpendicular to the conveying direction of a worm band, moves the objects perpendicular to this conveying direction, whereas a switch is provided to be actuated by the objects when reaching a stop.
The document FR-A-2 056 305 describes a horizontal pushing device for the displacement of parts, comprising a hydraulic engine driving a toothed wheel thanks to a thread. It has not been designed for transferring a parcel and the angular motion of the shaft is limited to amplitude smaller than one revolution.
The document U.S. Pat. No. 3,246,733 describes a conveying system with several output bands or chutes, opposite which individual pushers have been provided.
SUMMARY OF THE INVENTION
The purpose of the invention is to remedy the shortcomings mentioned above while providing notably a transfer device whose pushing element is driven by an accurate, simple and little cumbersome mechanism, which does not call for reversing the rotation direction and generally without any rotation speed variation.
Thus, the invention allows for a transfer without the object revolving round its axis and without changing the circulation direction of the said object.
The aim is therefore to enable the transfer of the objects outside the conveyor, in fixed and accurately reproducible position, regardless of the mass of the said object.
To this end, it is a first object of the invention to provide a transfer device designed for a linear conveyor such as defined in the claims.
Thanks to the invention, the engine rotation motion is transformed into an angular forward and return motion of a thrust lever. The motion of the lever follows a sine wave curve, uniformly varied with a mechanic acceleration and deceleration upon completion of each forward and return stroke.
This enables transferring the objects significantly faster than with known technologies, for a given conveying speed.
Obviously, according to the situation, the transfer unfurls with the conveyor in operation, slowing down or stopped.
According to a characteristic, the driving mechanism rotates in one direction only, which enables to do away with reversing the rotation direction of the lever's driving mechanism.
According to an embodiment, the lever pivots round a pin which is substantially parallel to the conveying direction, whereby this pin is located above or below the conveyor, whereas the free end of the lever follows a trajectory along an arc of a circle above or below the conveyor.
It is thus quite thinkable that the device should comprise several levers, actuated by a common driving assembly, whereby the control rods of the levers are installed on a common shaft, itself driven by the said assembly.
According to another embodiment, the lever pivots round a pin substantially perpendicular to the conveying direction, whereas the said pin is located above or below the conveyor, whereby the free end of the lever follows a trajectory along an arc of a circle, on a plane substantially horizontal, above or below the conveyor.
For instance, the pin is vertical, i.e. not only perpendicular to the conveying direction, but also intersecting the transfer direction.
In the embodiments, the lever is shaped or is machined in order to reduce the space requirements in the conveying direction, which enables arranging several transfer devices close to one another.
In the case of pins perpendicular to the conveying direction, such as vertical pins, an embodiment sets forth several articulated levers, whereas the length of the section of each lever located substantially at the same height as the corresponding pivot pin, is smaller than the distance between two adjacent pivot pins. This layout eliminates any risk of interference between two close transfer devices.
According to an embodiment, the device comprises means to sense the position of the rod's end, then so-called ‘irradiating’ rod, actuated at each revolution, upon completion of the return stroke of the rod and connected to an engine control device.
This enables controlling with accuracy the irradiating rod's driving assembly, especially to determine the precise stop position of the pendulum lever, in relation to the displacement of the rod's end.
This system also enables sensing and indicating the lever's retraction close to the conveyor and authorizing its operation or not.
A second object of the invention relates to at least one linear conveyor comprising a transfer device as mentioned, and defined in the claims.
This conveyor functions efficiently and its commissioning and operation costs are relatively low.


REFERENCES:
patent: 3045801 (1962-07-01), Graybeal
patent: 5010998 (1991-04-01), MacMillan
patent: 5217104 (1993-06-01), Pelletier
patent: 5464088 (1995-11-01), Koerber
patent: 27 56 552 (1979-06-01), None
patent: 2.056.305 (1971-04-01), None

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