The invention relates to a routing device designed to allow two incoming streams of flat objects, particularly streams of mail envelopes, to be grouped together into a single stream, in which device the objects, entering the stream alternately according to which stream they originate from, are transmitted one after another as in the incoming stream. As is known, certain operations in the processing of flat objects within a processing assembly are compatible with object flow rates which are markedly higher than they are in other operations with which they are associated, particularly in the case of an assembly for processing mail envelopes. Thus, for example, the operations of reading addresses, labeling or printing related to these mail envelopes allow a high flow rate along a conveying path, for example of the order of six objects per second. This flow rate cannot be achieved in the de-stacking operations which have to be performed at the headend of the path, because these operations only allow a flow rate which is practically half as high.
This means that constructors of assemblies of this kind have to feed an item of treatment equipment, the object flow rate of which is high, from several slower items of supply equipment which are arranged in parallel so that their respective flow rates are summed at the entry to the high flow rate equipment.
In a known embodiment, a routing device allows successive flat objects, such as mail envelopes, from one supplier equipment item to be inserted between the flat objects originating successively from another supplier equipment item. To do this, the flat objects of rectangular appearance from each supplier equipment item travel along one of their long sides along conveying paths which join each supplier equipment item to the routing device. The flat objects leaving an equipment item one after another to be conveyed to the routing device are positioned between a broad belt known as the backing belt, against which the flat objects are pressed by one of their large faces and a press belt which is pressed against the backing belt along the length of the conveying path joining the supplier equipment item in question to the routing device.
One of the conveying paths followed by the flat objects from one of the supplier equipment items meets the other conveying path followed by the flat objects from the other equipment item at the routing device, and does so at a relatively large angle of incidence xcex1, for example an angle of the order of 45xc2x0. This therefore leads to significant deformation of the flat objects when they pass through the routing device, because for a short moment of time the flat objects from one of the equipment items are bent in half at an angle xcex2=xcfx80xe2x88x92xcex1 which is the complementary angle to the angle of incidence. A solution of this kind is not truly satisfactory because the flat objects subjected to bending at the routing device while they are being conveyed may be damaged if they are not flexible enough or if they contain something really hard. Furthermore, in the latter incidence, it is possible that, in the absence of special steps, the hardware may become jammed and/or damaged. Patent document DE-21 45 270 discloses a routing device with two conveyors which converge symmetrically at a small angle toward a downstream conveyor which has the effect of limiting the inflection of the objects in the zone of convergence.
The object of the invention is to propose an even further improved routing device which allows two incoming streams of flat objects, particularly mail envelopes from two supplier equipment items to be grouped together, in which device the flat objects may have very varied thicknesses and hardnesses.