EP2176150B1 - Conveyor with deformable wheels applying a progressive clamping force - Google Patents

Abstract

A conveyor device for conveying flat objects on edge, which device comprises at least two wheels having elastically deformable treads and disposed facing each other so as to move a flat object on edge by pinching and friction. The two wheels are arranged in such a manner as to exert a pinching force on the flat object on edge that varies progressively as the flat object is driven forwards.

Description

The invention relates to a device for conveying flat objects comprising at least one pair of wheels with elastically deformable tread which are arranged in opposition so as to move a flat object by pinching and friction.

The invention relates more particularly to a conveying device capable of moving a wide spectrum of flat mail items ranging from coupons of very small thickness (of the order of 0.5 mm) to flat objects of large size and very large thickness (of the order of 30 mm).

European patent document is known EP-1194249 such a conveying device which is part of a more complex system called "synchronizer" in a postal sorting machine.

This synchronizer has several stages with two levels of coupled motorized wheels, which have a rotational speed which is controlled to synchronize the movement of a mailpiece (inserted between the mated wheels in opposition) with the displacement of a bucket of a bucket carousel in which this shipment is to be injected. In this known arrangement, each current mail is pushed between the wheels of the input stage of the synchronizer by an unstacking member which is in this case a perforated belt moved in front of a suction nozzle.

The control of the synchronizer takes into account the instant of passage of the current item in front of a sensor placed at the input of the synchronizer and the moment of passage of a bucket (in which the sending must be injected) in front of another sensor placed along the bucket circulation path.

From a relatively constant speed of displacement of the sending between the output of the synchronizer and the point of injection in a bucket, an acceleration curve of the speed of the sending in the synchronizer is calculated to make coincide the passage of the bucket with the arrival of the consignment. In practice, at the output of the synchronizer the sendings follow each other in series with a constant gap between their front edge which corresponds to a gap between four consecutive cups of the carousel.

In this synchronizer, the input stage is formed of at least two wheels in opposition, these wheels having an elastically deformable tread of the same diameter. The two wheels are in contact with each other by the outer surface of the treads.

When a consignment is inserted on edge between the wheels in opposition of the input stage, its front edge deforms the treads of the wheels in opposition substantially on the contact line of the treads. By fading, the treads of opposing wheels exert on the opposite surfaces of the sending a pinch force which is spread over substantially the entire height of the consignment. Once the consignment is fully engaged between the two opposite wheels of the input stage, it is driven (with some acceleration) by friction towards the wheels of the second stage and so on until the output of the synchronizer .

It has been found that for the thickest shipments where the deformation of the treads is the largest, the insertion time of these shipments between the wheels of the entry stage is also greater than for that of the shipments more so that these thick mailings take longer to cross the synchronizer than the finer shipments. Since the difference between two consecutive shipments must be constant (or be equal to a multiple of this constant difference value), it has been found that the synchronizer as described above was required to delay the moment of injection. some of the thickest shipments, for example by doubling or tripling the gap separating them respectively from the items preceding them. This has the effect of affecting the rate of the postal sorting machine.

The object of the invention is to overcome this disadvantage.

For this purpose, the subject of the invention is a conveying device on edge of flat objects comprising two axes, on each of which are arranged, in opposition and in a symmetrical manner, at least two wheels with an elastically deformable tread so as to move a flat object on singing by pinching and friction, characterized in that the two wheels are arranged so as to exert a pinching force on the flat object on edge which is progressive in the direction of the height as the flat object is driven into displacement.

This progressive clamping effort can be obtained according to the invention, by arranging the wheels so as to arrange between the treads a substantially V-shaped clamping gap. For this, the opposing wheels can be mounted on inclined axes. from 5 to 10 °.

The wheels can also be arranged so as to provide between the treads a substantially stair-shaped nip. For this, according to the invention, each tread is formed in several rings of different diameters. There are therefore several superimposed treads that may or may not be part of as many different wheels superimposed. It is conceivable to put between the adjacent wheels a spacer to separate them or on the contrary to superimpose them without spacer and in addition to stiffen them with axial rods distributed around the periphery of the wheel hub to limit the phenomenon of floating of the treads when the wheels are spinning at high speed.

These two configurations of opposing wheels contribute to obtain a time of insertion of the thick shipments between the wheels of the input stage of the synchronizer almost identical to that of the smaller thicknesses.

The invention can be applied to a conveyor-synchronizer in which one has wheels in opposition on one or more superimposed levels as for the synchronizing conveyor described in the patent EP-1194249 .

Of course, the principle of the invention can be applied to any wheel conveyor "elastically deformable" adapted for moving flat objects by pinching and friction.

• La figure 1 illustre une configuration de roues avec un intervalle de pincement sensiblement en forme d'escalier.
• La figure 2 illustre une configuration de roues avec un intervalle de pincement sensiblement en forme de V.

The conveying device according to the invention is described below in connection with the drawing.

• The figure 1 illustrates a wheel configuration with a substantially stair-shaped nip interval.
• The figure 2 illustrates a wheel configuration with a substantially V-shaped nip.

On the figure 1 elastically deformable wheels mounted in opposition are illustrated on two parallel axes A1, A2 and a flat object which is on edge, for example a flat postal item 1.

The two axes A1, A2 are rotatably mounted on a plate 2 which is the sole of a conveyor that can be part of a device for unstacking postal items in a postal sorting machine.

As visible on the figure 1 two levels N1 and N2 are represented of motorized wheels in opposition. R1 denotes first elastically deformable wheels whose tread has a diameter for example of about 150 mm. R2 denotes second elastically deformable wheels whose tread has a diameter of about 140 mm. R3 denotes third elastically deformable wheels whose tread has a diameter of about 130mm.

These wheels R1, R2 and R3 are arranged in opposition and symmetrically on the two axes A1 and A2. For the level N1, there is thus the superposition (going from the bottom to the top) of R1, R2, R3 and R2. For the level N2, we have the superposition R2, R1. On the two levels N1 and N2, the wheels therefore define a stair-shaped pinching gap in the direction of the height.

By inserting (in a direction perpendicular to the plane of the sheet) between the wheels in opposition, the sending 1 is first pinched between the wheels R1 in opposition which disappear on both sides of the sending and then between the wheels R2 of smaller diameter than the wheels R1 and finally between the wheels R3 of smaller diameter than the wheels R2.

So the total pinch force exerted on the faces of the shipment is progressive over time as the shipment enters between the wheels in opposition of different diameters.

In the case of postal sorting example, each wheel has a tread of a height of 15 mm which is connected to a hub by inclined flexible fins. It is conceivable that the wheels R1, R2, R3 have different levels of hardness (at deformation) or that the wheels on one axis have the same level of hardness but which is different from that of the wheels located on the other axis.

On the figure 2 a wheel configuration has been illustrated in which the treads define a V-shaped nip. Here the axes A 'are arranged inclined relative to one another on the plate 2' and carry each two levels N1 'and N2' of wheels R. The wheels R here have an identical diameter.

When the sending 1 'advances (perpendicular to the plane of the sheet) between the two inclined axes, its front edge is progressively pinched, as it moves forward, between the treads of the wheels R of the level N2 '(lowest level) then between the treads of wheels R level N1' (it is represented by the lines E, the points of contact between the consignment and wheels R).

It is of course possible to combine both inclined axes as represented on the figure 2 with wheels of different diameters as shown on the figure 1 without departing from the scope of the invention.

Claims (6)

1. A conveyor device for conveying flat objects (1; 1') on edge, which device comprises two axles (A1, A2; A'), on each of which at least two wheels (R1, R2, R3; R) having elastically deformable treads are disposed symmetrically facing each other so as to move a flat object on edge by pinching and friction, characterized in that the two wheels are arranged in such a manner as to exert a pinching force on the flat object on edge that varies progressively in the height direction as the flat object is driven forwards.
2. A device according to claim 1, in which said wheels are arranged in such a manner as to form a substantially V-shaped pinching gap between the treads.
3. A device according to claim 1 or claim 2, in which said wheels are arranged in such a manner as to form a pinching gap that varies substantially stepwise between the treads.
4. A device according to claim 3, in which each tread is made up of a plurality of rings of different diameters.
5. A device according to any one of claims 1 to 4, in which each wheel comprises a hub that is connected to a tread by inclined fins.
6. A synchronizer-conveyor for mailpieces, including a conveyor device according to any one of claims 1 to 5.

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