Abstract:
A device for dispensing single components, in particular rivets of different shapes and sizes, wherein the rivets are conveyed to a riveting station one by one in a given direction along a path; the rivets are moved along and within an elastic sheath ( 11 ) by a pressure source (P); the device also includes a device for storing the components and includes a holder ( 24 ) for feeding the components one by one to the elastic sheath ( 11 ); the device provides for the uniform and steady feeding of rivets to riveting machines such as are used in the aircraft industry.

Description:
The present invention concerns a device for distributing parts singly and a device for storing these parts. 
     More particularly, the parts in question are rivets intended to feed a riveting machine in a continuous and uniform manner. 
     BACKGROUND AND OBJECTS OF THE INVENTION 
     It is well known that in order to ensure uniform rivetting, which is imperative (particularly in the field of aeronautics) it is necessary to feed a riveting machine in the most uniform manner possible. Each rivet must arrive at the riveting station in the right direction and one by one. Now, a riveting machine may be fed by several types of rivets with different lengths, diameters and shapes of the head. It is thus necessary to establish separate storage devices each containing a particular type of rivet. It is then necessary to use a selection device for a particular type of rivet and means for distributing this rivet singly to a riveting machine. 
     At the present time, however, no device exists for distributing rivets singly capable of delivering rivets of different sizes and shapes, always in the same position, while guiding them correctly along their path. 
     The aim of the present invention is to overcome all these disadvantages and more particularly to create a device for distributing parts singly enabling parts of different sizes and shapes to be delivered, always in the same position. Such a device must be simple, low in cost, and easy to use and manufacture. 
     DESCRIPTION OF THE INVENTION 
     For this purpose, the present invention concerns a device for distributing parts singly, more particularly rivets, wherein it comprises: 
     a deformable elastic means having a substantially tubular shape in the passive state comprising a central bore with a narrow section and inlet and outlet openings, said elastic means being capable, in the active state, of expanding radially so as to receive and guide a part in its central bore, and 
     a source of pressure capable of subjecting the internal bore of the elastic means to an excess pressure and to bring about a radial expansion of this so as to move, one by one, each part placed at the inlet orifice towards the outlet orifice of the elastic means. 
     Thus, the invention consists of using, as a distribution device, a deformable elastic means, for example a sheath made of extensible material (of the thin balloon type) for distributing one by one parts conveyed to the inlet of this distribution device, and leading them to the outlet (namely to a riveting machine) by the action of a source of pressure (for example compressed air). 
     Advantageously, in order to prevent the elastic means bursting or deforming in an irreversible manner, this elastic means is placed inside a tube having a certain radial rigidity so as to limit the radial expansion of the elastic means. This tube may on the other hand have a certain flexibility in the longitudinal direction. 
     Advantageously, the device for distributing parts singly according to the present invention comprises a means for storing parts. This means of storage is capable of containing a plurality of parts and of delivering them one by one, to order, to the elastic means. 
     The means of storage according to the invention consists of an assembly of tubular elements, in which the parts to be stored are stacked one behind the other. A retaining means enables the first of these parts to be freed, to order, while holding all of the other parts. 
     When several storage means are associated, each containing different parts, the distribution device according to the invention comprises, in addition, a means of selection capable of receiving a part derived from any means of storage whatsoever with a view to leading it to the inlet orifice of the elastic means. 
     The present invention concerns a storage device capable of being used in a distribution device according to one of the preceding claims, wherein the said device comprises: 
     a tubular element, a connector and a retaining element, each having an internal bore capable of housing and guiding a plurality of parts placed one behind the other, 
     a source of pressure, capable of exerting a pressure inside the central bore, on a first part of the said plurality and, 
     retaining means provided in the retaining element, capable of retaining the first part and the following part, to liberate the first part to order and to put the following part in readiness by causing it to pass to the first position and thus to deliver each part of the plurality singly. 
     Such a storage device is more particularly provided with retaining means capable of delivering the first part stored and of retaining all the others. As soon as the first part is delivered, the second takes its place, in order to be ready for the next delivery. 
     Advantageously, the retaining means consists of two rams operating in opposition and acting to retain the first and second parts stored, respectively. Thus, when the first part stored is retained, the second is not and vice-versa. 
     Advantageously, these two rams are arranged orthogonally in relation to each other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objectives, aims and features of the present invention will become more apparent from the following description, which is given by way of information, with reference to the accompanying drawings in which: 
     FIG. 1 is a diagrammatic view in longitudinal section of an elastic means according to the invention, 
     FIG. 2 is a diagrammatic view in longitudinal section of the elastic means of FIG. 1 placed inside a tubular element, 
     FIG. 3 is a similar view to FIG. 2 showing the movement of a part inside the elastic means, 
     FIG. 4 is a diagrammatic view in longitudinal section showing a means of storage associated with the elastic means of FIG. 2, 
     FIG. 4 a  is an exploded detail view of an alternative embodiment to that shown in FIG. 4; 
     FIGS. 5 to  7  are diagrammatic views in longitudinal section of the means of storage showing the operation of the retaining means, 
     FIG. 8 is a perspective view, partially cut away, showing a device for distributing parts according to the invention, comprising an elastic means, a means of selection and a plurality of means of storage and, 
     FIG. 9 is a diagrammatic view in transverse section of the means of selection shown in FIG.  8 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     According to the embodiment shown in FIG. 1, the distribution device  10  according to the invention comprises: 
     a deformable elastic means  11 , in the form of a flat extensible sheath and, 
     a source of pressure (not shown), here compressed air, the action of which (arrow P) is applied to the inside of the elastic means  11  and causes the central bore  12  of this to expand. 
     The elastic sheath  11  is folded back and attached to a ring  13  firmly fixed to a frame (not shown). 
     A part  14 , here a rivet, moves inside the sheath  11  from an inlet orifice  16  towards an outlet orifice  15  (arrow P) under the action of compressed air. 
     It will be noted that, under the action of the pressure exerted, the sheath  11  expands radially and thus enables the rivet  14 , also subjected to the source of pressure (exerted on its head), to move forward in the sheath. The rivet  14  thus forms, as it were, a stopper closing off the sheath and preventing air under pressure from escaping directly through the outlet orifice  15  of this sheath. 
     On account of this, the rivet  14  is pushed progressively and uniformly towards the outlet orifice  15 . It will be easily understood that by virtue of the radial expansion of the sheath, the latter may receive rivets of different sizes and shapes. Moreover, since the sheath grips the rivet and only expands after the head of this rivet has passed, the rivets are guided and held all along their path inside the sheath. 
     As a variant, in order to prevent the sheath from bursting or deforming in an irreversible manner, it is placed inside a tubular element  17  (FIGS. 2 and 3) having a longitudinal bore  19 . This tubular element has a certain radial rigidity and a longitudinal flexibility. 
     In this case, the inlet orifice  16  of the sheath is folded back and fixed (for example by gluing) to the end  18  of the tubular element itself. The principle whereby the rivet  14  moves forward inside the elastic sheath  11  remains the same. However, as will be better seen in FIG. 3, radial expansion of the sheath  11  is limited by the presence of the tubular element  17 . 
     As shown in FIG. 4, such a distribution device may comprise, in addition, a storage device  20 . This storage device is connected to the elastic means by a means of connection  21  of a known type. 
     The storage device comprises a hollow tubular element  22  having a central bore  23 , connected to a retaining element  22   b  by means of a conventional connector  22   a . All of these elements  22 ,  22   a  and  22   b  have the same central bore  23 . 
     The rivets  14   1  to  14   n  (n being a whole number greater than 1) are stacked one behind the other in this central bore  23 . 
     A retaining means  24 , consisting of two pistons  25  and  26 , mounted orthogonally in relation to each other, is placed in the retaining element  22   b . These pistons are able to extend alternately inside the central bore  23 . In full extension (FIGS. 5 to  7 ), the pistons contact the stem of one of the rivets  14   1  or  14   2 , and thus lock it in position in relation to the element  22   b.    
     The action of the pistons  25 ,  26  is controlled by a 5/2 valve. Thus (FIG.  5 ), the piston  25  (further downstream in the element  22   b ) holds the part  14   1  by its head and locks it in position. All the other parts  14   2  to  14   n  are on account of this also held in position while the piston  26  (further upstream in the element  22   b ) is retracted. 
     A certain pressure exists inside the central bore  23 . This pressure is capable of acting on the first part  14   1  in such a way that this part would have the tendency to leave the element  22   b  if it were not held by the ram  25 . 
     When the part  14   1  is conveyed to the elastic means, the downstream ram  25  retracts and frees the part  14   1  while the upstream ram  26  is deployed and comes into contact with the stem of the rivet  14   2 . The rivet  14   2  and those following are thus held in position (FIG.  6 ). As soon as the rivet  14   1  leaves the element  22   b  (FIG.  7 ), the pair of rams are once again brought into play to deploy the downstream ram  25  and to retract the upstream ram  26 . There is then a return to the same position as in FIG. 5, but with the rivet  14   2  locked in the first position. 
     By virtue of such a retaining mechanism, it is thus possible to control the departure, one by one, of rivets stored in the storage device  20 . 
     It will be noted that the rams  25  and  26  retract inside the retaining element  22   b  under the action of compressed air and move forward in the bore  23  due to two springs (not shown). As a result of this, if there is any blockage in the compressed air circuit, the springs lock the rams in the forward position (inside the bore) which locks all the parts  14  and prevents damage to the riveting machine. This makes for increased safety when this storage device is employed. 
     When several storage devices  20  are linked together (FIG.  8 ), for example by a frame  30 , the distribution device as claimed in the invention comprises: 
     the plurality of storage devices  20 , 
     a means of selection  31  and, 
     the elastic means  11  in its tubular element  17 . 
     The means of selection  31  is a single plate which can be moved in two orthogonal directions (arrows F and G) so as to enable the opening  16  of the elastic means  11  carried by the selection means  31  to be brought into coincidence with the outlet orifice (not visible in FIG. 8) of any one of the storage devices  20 . 
     In the example shown, the means of selection  31  is associated with four storage devices, but obviously the number of storage devices may be greater or smaller. 
     As is clearly visible in FIG. 9, the means of selection  31  comprises two slides  32  which can slide along two guides  33  and  34  orthogonal to each other. 
     Thus, the body  35  of the means of selection, provided with an orifice  36  capable of receiving the elastic means  11  (not shown) is able to coincide (by movement in the direction of the arrows F and G) with one of the outlet orifices of the storage devices. 
     As a variant, and as shown in the detail D of FIG. 4, the fitting of the storage device  20  into the elastic means  11  is facilitated by providing notches  40 , arranged at the end of each of these elements. These notches constitute a rapid means of connection between the various elements to be connected and advantageously enable the various internal bores to be centered, so as to create a continuous conduit for the parts  14  without any surface discontinuities. 
     The present invention is of course not limited to the embodiments described above and encompasses any variant available to a person skilled in the art. More particularly, such devices for distributing or storing parts may be used for parts other than rivets, for example screws, nails, staples etc.