Abstract:
An accumulator having a general U-shape includes two parallel endless belt conveyors, communicating through an endless belt conveyor with semicircular trajectory borne by a mobile carriage driven by a translation movement parallel to the parallel conveyors. The accumulator for guiding ( 20, 21, 22, 23 ) the upper side of the endless belt ( 5 ) of the first conveyor ( 4 ) adapted to lower the downstream part of the upper side located beneath the semicircular conveyor ( 10 ). The lowering places in the same plane, the transport plane of the first conveyor ( 5 ) and the transport plane of the semicircular conveyor ( 10 ). The guide is simultaneously mobile with the carriage ( 16 ) for manoeuvring in translation the semicircular conveyor ( 10 ) so that the downstream end of the transport plane of the first conveyor ( 5 ) should follow the displacement of the upstream end of the semicircular conveyor ( 10 ).

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This is the 35 USC 372 national stage of international application PCT/FR01/01042 filed Apr. 5, 2001, which designated the United States of America. 

   FIELD OF THE INVENTION 
   This invention concerns an “accumulator” device, enabling continuous regulation of the transfer of products between an upstream unit and a downstream unit. 
   BACKGROUND OF THE INVENTION 
   Within the framework of manufacture of biscuits, chocolate bars, mechanical parts or others . . . the various units of the production line are generally connected by transfer systems, often endless belt conveyors. In some cases, and notably when the downstream receiving unit calls for regular supply, particular transfer devices are used, capable of absorbing jerky throughputs of the upstream machine(s), and capable of storing at least temporarily the products when the downstream unit is not working correctly. 
   The document FR-A-2 524 436 describes such a transfer regulating device, composed of two endless belt linear conveyors, arranged parallel to one another and communicating via a connection system in the form of a circular plate or of semicircular conveyor, borne by a mobile carriage driven by a translation movement parallel to said parallel conveyors. The translation movement of the circular plate or of the semicircular conveyor above linear conveyors is controlled to increase or reduce the length of the transport plane of the products, in relation to the storage requirements or to the emptying possibilities. 
   As the transport plane of the connection system (circular plate or semicircular conveyor) is situated above the transport planes of the linear conveyors, the transfer of the products at the upstream and downstream ends of this connection system is performed via tilted ramps. However, these ramps may lead to erratic transport of the products; they may cause degradations, in particular within the framework of the treatment of fragile products. 
   SUMMARY OF THE INVENTION 
   This invention suggests a new structure of an accumulation facility enabling to remedy this shortcoming. 
   The accumulator device according to this invention is of the type composed of a first linear conveyor with fixed ends; with an endless belt, adapted to receive the products from an upstream unit, and of a second linear conveyor, also with fixed ends and with endless belt, arranged parallel to the first conveyor, adapted to deliver the products towards a downstream unit; these first and second conveyors are communicating via a conveyor with endless belt with semicircular trajectory which is provided above them and which is borne by a mobile carriage driven by a translation movement parallel to said first and second conveyors The transport plane of the products, with variable length according to the position of the semicircular conveyor, is composed of the upstream section of the upper side of the belt of the first conveyor, of the upper side of the belt of the semicircular conveyor and of the downstream section of the upper side of the belt of the second linear conveyor. 
   According to this invention, this accumulator device comprises means for guiding the upper side of the belt of the first conveyor, adapted to lower the downstream section of said upper side situated beneath the semicircular conveyor and which does not serve as a transport plane of the products, said lowering enabling to place in the same plane, the transport plane of said first conveyor and the transport plane of said semicircular conveyor, said guiding means being simultaneously mobile with the carriage for maneuvering in translation said semicircular conveyor so that the downstream end of the transport plane of said first conveyor should follow the displacement of the upstream end of said semicircular conveyor. 
   Still according to the invention, the means for guiding the upper side of the first conveyor are borne by the mobile carriage of the semicircular conveyor. 
   According to another characteristic, the section of the endless belt forming the transport plane of the first conveyor is associated with retractable supporting means maneuvered in relation to the translation displacement of the semicircular conveyor. 
   According to a preferred embodiment, these supporting means have the shape of retractable rolls, and according to a preferred arrangement, these retractable rolls are maneuvered by the mobile carriage of the semicircular conveyor. 
   In a particularly interesting embodiment, the supporting rolls of the belt are each mounted on a bracket fitted with at least one toothed sector which cooperates with a rack borne by the mobile carriage of the semicircular conveyor, to lower or raise each roll in relation to the displacement of said carriage. 
   According to another particularity, the translation maneuvering means of the mobile carriage of the semicircular conveyor are composed of a traction chain whereof both ends are interconnected with said carriage, and which winds around two pulleys whereof the one is motorised. This mobile carriage comprises means for guiding along a longitudinal rail, which rail also serves as a means for guiding the upper side of the traction chain via lateral guides provided on the links of said chain, or at least on some of them. 
   According to a preferred embodiment, similar belt guiding and supporting means are provided on the second linear conveyor, so that its transport plane is situated on the same plane as the transport plane of the semicircular conveyor. 
   In other possible embodiments, the upper side of the second linear conveyor of the facility can be provided beneath the semicircular conveyor, whereas a complementary device is then arranged in the extension of the downstream end of said semicircular conveyor to follow the transfer of the products on the underlining transport plane of the second linear conveyor. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     But the invention will be better illustrated, without being limited thereto, using the following description of various possible embodiments, given solely for exemplification purposes and represented on the appended drawings, wherein: 
       FIG. 1  is a top diagrammatical view of an accumulation facility according to this invention; 
       FIG. 2  is a longitudinal sectional diagrammatical view along  2 — 2  of the accumulation facility illustrated on  FIG. 1 ; 
       FIG. 3  is an enlarged view of the right-hand section of  FIG. 2 ; 
       FIG. 4  is a section along  4 — 4  of  FIG. 1 ; 
       FIGS. 5   a  and  5   b  illustrate, diagrammatically, the maneuvering of the supporting rolls of the endless belts of the first and second linear conveyors; 
       FIG. 6  corresponds to the same sectional view as  FIG. 2 , but with a position different of the semicircular conveyor; 
       FIG. 7  is a diagrammatical sectional view along  7 — 7  of  FIG. 1  showing the structure of the second linear conveyor; 
       FIGS. 8 and 9  show possible embodiments of the second linear conveyor and of the transfer principle on said conveyor of the products from the semicircular conveyor; 
       FIG. 10  is a lateral view showing one of the ends of the mobile carriage of the semicircular conveyor with its guiding means and its traction chain; 
       FIG. 11  is a cross-sectional view showing the guiding means of the mobile carriage and the guiding system of its traction chain. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As represented on  FIG. 1 , the accumulator device is designed to be positioned between an upstream unit (for example a biscuit baking oven) which supplies the products via an inlet transport device  1 , and a downstream unit (for example a packaging facility) supplied by an outlet transport device  2 . 
   This accumulator device comprises:
         a first linear conveyor  4  with endless belt  5  placed in the extension of the. inlet transport device  1  and whereof the upper side of the belt is driven along the direction of the orientation arrow  6 ,   a second linear conveyor  7  with endless belt  8 , arranged parallel to the first conveyor  4  in the extension of the outlet transport device  2  and whereof the upper side of the belt is driven along the direction of the orientation arrow  9 , and   a semicircular conveyor  10 , also with endless belt  11  whereof the upper side is driven along the orientation arrow  12 ; this conveyor  10  forms a connection structure of both linear conveyors  4  and  7 .       

   The linear conveyor  10  is a conventional semicircular conveyor; it is placed on both linear conveyors  4  and  7  so that the upper side of its endless belt  11  picks up the products transported by the first conveyor  4 , to dump them onto the second conveyor  7 . 
   Besides, this semicircular conveyor  10  is borne by a carriage  16  which is mobile in translation along the orientation arrow  17 , parallel to the longitudinal axes of the linear conveyors  4  and  7  to enable to modify the length of transport of the products on the facility. It can be understood that in relation to the direction of displacement of the semicircular conveyor  10 , the transport length of the products is increased or reduced between the inlet  1  and outlet  2  transport devices. 
   The operation of the facility is controlled based upon the speeds of the upstream and downstream units. Based upon the corresponding information which determines the accumulation requirements, the speeds of the endless belts  5 ,  8  and  11  of the conveyors  4 ,  7  and  10  are monitored, as well as the translation displacement of the mobile carriage  16 . 
   Possibly, a cell  18  for detecting the products is placed at the inlet zone of the products onto the accumulator, i.e. the transfer zone of the inlet transport device  1  onto the first conveyor  4 . Based upon the information provided by this cell  18 , one can fine-tune the speed of at least one of the endless belts of the accumulator device and/or the displacement of the mobile carriage  16  to store the products or the rows of products with a regular pitch. 
   The loading of the accumulation facility is thus optimised and the products can be delivered at regular rate towards the downstream unit. 
   In order to limit the disturbances of the products during transport, the accumulation facility according to this invention comprises means which enable to place on the same plane, the transport plane of the first linear conveyor  4  and the transport plane of the semicircular conveyor  10 . 
   As can be seen on  FIGS. 2 and 3 , the endless belt  5  of the linear conveyor  4  is guided by rolls  20 ,  21 ,  22  and  23  interconnected with the mobile carriage  16  in order to lower its downstream section  5 ′ situated beneath the semicircular conveyor  10  and which does not serve as a transport plane of the products. This deviation of the trajectory of the endless belt  5  enables to create a space wherein is accommodated the semicircular conveyor  10  so that the upper side of its endless belt  11  is placed in the same horizontal plane as the upper side of the endless belt  5  of the linear conveyor  4 . 
   The first guiding roll  20  of the upper side of the endless belt  5  is placed opposite the roll  24  which guides the upstream end of the semicircular conveyor  10  in order to provide quasi continuity of the transport plane of the products. As guiding means  20 ,  21 ,  22  and  3  of the upper side of the endless belt  5  are interconnected with the mobile carriage  16 , one may easily understand that during displacements of this mobile carriage  16 , the downstream end of the transport plane of the linear conveyor  4 , delineated by the mobile roll  20 , follows the upstream end of the semicircular conveyor  10 , delineated by the mobile carriage  24 . 
     FIG. 2  shows that the upstream end of the conveyor  4  delineated by the fixed roll  26  is situated at higher level than its downstream end delineated by the fixed roll  27 . 
   Still on the same Figure, one can also note the drum  28  which drives the endless belt  5  via a motorised system  29 . 
   To ensure correct transport of the products, the section of the upper side of the endless belt  5  situated upstream of the guiding roll  20  is supported by retractable free bending rolls  30 , spaced regularly, maneuvered by the mobile carriage  16 . 
   As shown on  FIGS. 2  to  5 , these rolls  30  are each mounted on a toggle bracket  32  which has here the shape of lateral arms hinged around a pivoting axis  33 . This axis  33  is parallel to the axis of the rolls  30 . 
   The clearance of the bracket  32  is delineated by two stops ( FIGS. 5   a  and  5   b ), the one  34  fixing the upper position of the roll  30  ( FIG. 5   a ) and the other  35  fixing its lower position ( FIG. 5   b ). 
   One or both lateral arms  32  comprise a toothed sector  36  adapted to co-operate with a rack  37  arranged on the mobile carriage  16  to lower or raise the rolls  30  in relation to the displacement of the semicircular conveyor  10 . When the mobile carriage  16  moves towards the upstream end of the linear conveyor  4  and arrives close to a belt-supporting roll  30 , the rack  37  actuates the toothed sector  36  ( FIG. 5   a ) to cause the bracket  32  to pivot and to lower the corresponding roll  30 . The bracket  32  touches the stop  35  and in this lowered position, the roll  30  does not disturb the displacement of the mobile carriage  16 . 
   In reverse direction, when the mobile carriage  16  moves towards the downstream end of the linear conveyor  4 , the rack  37  actuates the toothed sector  36  ( FIG. 5   b ) to cause the bracket  32  to pivot round the axis  33  and to raise the corresponding roll  30 . The rack  37  releases the toothed sector  3  when the roll  30  reaches a high position, the bracket  32  then rests stably on the stop  34 . 
   When the upper side of the endless belt  5  is in low position, it rests on the rolls  30 , on complementary rolls  38  spaced regularly and, at its lateral edges on the bodywork of the conveyor. 
   As can be seen on  FIGS. 2 and 5   b , the upper side  5 ″ of the endless belt  5  is supported by rolls  39 . 
     FIG. 2  shows the accumulation facility with the semicircular conveyor  10  and its mobile carriage  16  positioned at the downstream end of the linear conveyor  4 , whereas all the supporting rolls  30  are in raised position. In such a position, the trajectory of the products on the accumulation facility is maximal. 
   On  FIG. 6 , the semicircular conveyor  10  and its mobile carriage  16  are placed closed to the upstream end of the linear conveyor  4  and all the supporting rolls  30  are in lowered position, whereas the trajectory of the products on the accumulation facility is here minimal. 
   As can be seen on  FIGS. 4 and 7 , the second linear conveyor  7  has a structure identical to that of the conveyor  4  described above. Thus, the upper side of the endless belt  8  of this conveyor  7  is guided by rolls  20 ′,  21 ′,  22 ′ and  23 ′ interconnected with the mobile carriage  16  ( FIG. 7 ) in order to lower its upstream section  8 ′ situated beneath the semicircular conveyor  10  and which does not serve as a transport plane of the products. 
   As explained previously, this lowering of the belt enables to place the upper side of the endless belt  11  of the semicircular conveyor  10  in the same horizontal plane as the active upper side of the endless belt  8  of the linear conveyor  7 , in order to limit the disturbances of the products as they pass from conveyor to the other. Similarly, retractable rolls  30  are provided to support the upper side of the endless belt  8  forming the downstream transport plane of the products. Similarly to the first linear conveyor  4 , the bracket  32  of the rolls  30  comprises a toothed sector  36  which enables to raise or lower the rolls by means of a manoeuvring rack  37  arranged on the mobile carriage  16 . 
   In embodiment variations, the upper side of the endless belt of the second conveyor can be situated at a lower level than that of the upper side of the semicircular conveyor  10 . In such a case, a complementary device is provided in the extension of the downstream end of the semicircular conveyor to receive the products and to accompany them on the underlining transport plane of the second linear conveyor. This arrangement enables to simplify the facility since the second linear conveyor may then consist of a conventional conveyor with endless belt. 
     FIG. 8  illustrates a variation of such type wherein the downstream end of the semicircular conveyor is fitted with a mobile sorting system  40  which enables to place the products on their edges and resting against one another. 
     FIG. 9  illustrates another variation of such type wherein the downstream end of the semicircular conveyor is fitted with a simple guiding sheet  41 . This sheet can also be replaced with a small tilted conveyor, with endless belt. 
   In these various embodiments, as the products are transferred from the semicircular conveyor towards the linear conveyor with a level slope, the risks of disturbances or of degradations are limited. 
   In the accumulation facility according to the invention, the mobile carriage  16  which bears the semicircular conveyor  10  is mounted on wheels  42  resting on raceways provided on both parallel linear conveyors  4  and  7 . This carriage  16  is maneuvered by a traction chain  44  laid out between both linear conveyors  4  and  7 . The traction chain  44  winds around two pulleys  45  and  46  whereof the one (the pulley  46 ) is motorised, and both its ends are fixed to the carriage  16  to enable to drive said carriage into one direction or the other. 
   As represented on  FIGS. 4 ,  10  and  11 , the mobile carriage  16  is guided in translation on a rail  47  via lateral rollers  48  of vertical axes. The upper side of the traction chain  44  slides on this rail  47 , held by lateral guides  50 ; these guides  50  may equip all the links of the chain  44  or only some of them. 
   On  FIG. 11 , it can be noted that the lower side of the chain  44  is housed in a hollow beam  52 .