Patent Publication Number: US-2011061356-A1

Title: Device for supplying a leaf-stripping device with tobacco plants

Description:
This invention relates to the supply of a leaf-stripping device with tobacco plants, and more particularly a leaf-stripping device with a high working speed. 
     After the harvest, tobacco plants are generally put out to dry in a dryer. 
     During this drying stage, the tobacco plant is preserved in the form of a stem that comprises different foliar stages. 
     Subsequently, the leaf-stripping of the tobacco plants takes place when said plants have reached a given degree of drying, monitored by the producer. 
     This leaf-stripping therefore consists in separating the leaves from the stem of each plant, preferably by avoiding mixing the leaves that are obtained from different foliar stages of the plant and by implementing a sorting to eliminate rotted or fermented leaves. 
     According to a first method, this leaf-stripping can be conducted manually by several farm workers. 
     Although justifiable in terms of quality, manual leaf-stripping takes too long and is too expensive for the tobacco producer, and in addition, the manual labor for this type of work is increasingly difficult to find. 
     Consequently, automated leaf-stripping devices have been developed so as to reduce the time and the manual labor necessary for this operation. 
     For example, a first leaf-stripping device that is described in the French Patent Application FR 08 55200 in the name of the same applicant is known. 
     This first leaf-stripping device  10  of the prior art, illustrated in  FIGS. 1 and 2 , comprises at least one station  12  for supplying tobacco plants, a station  14  for discharging leaves separated from stems, and means  16  for transferring plants from the supply station to the discharging station  14 , whereby means  18  for separating leaves are inserted between the supply station and said discharging station. 
     This first leaf-stripping device provides an effective solution to the sorting of leaves at the discharging station using preparation means with leaf-stripping comprising means for orienting leaves in the same direction and guide means designed to collect the leaves of the same foliar stage. 
     However, this first leaf-stripping device of the prior art has one drawback: it requires manual loading of the plants at the supply station of the device by an operator  20 , shown in dotted lines in  FIG. 1 , whereby the tobacco plants are loaded individually by said individual, i.e., one plant brought in after the next to be deposited on the transfer means  16 . 
     With the transfer means  16  comprising at least one carrousel in the form of a closed-chain conveyor supporting bars equipped with hooks for receiving tobacco plants, this loading mode imposes an intermittent operation on the leaf-stripping device  10 , whereby the transfer means  16  have to be stopped or slowed down to make it possible for the operator  20  to deposit each tobacco plant on the hooks of a bar. 
     Gradually, the production goals of the tobacco producers have increased, and if the old automated leaf-stripping devices of the prior art offered speeds of approximately 1,000 plants per hour, a device such as the one that is described in French Patent Application FR 08 55200 makes it possible to exceed 2,000 plants per hour. 
     Although advantageous in terms of output, this high speed is difficult and even impossible to maintain for an individual who is responsible for manually supplying the leaf-stripping device: the plant-loading frequency becoming too difficult and tiring. 
     A second leaf-stripping device of the prior art, described in the French Patent Application published under Number FR 2 786 991, provides a device for loading tobacco plants placed upstream from the means for separation of the leaves, whereby this loading device consists of guides pitched downward and receiving the tobacco plants in horizontal position and with dangling leaves. 
     Said loading device therefore makes it possible to deposit several tobacco plants simultaneously on standby at the supply station of this second leaf-stripping device of the prior art. 
     However, the buffer loading offered by the guides of this loading device is very limited, several plants at the very most. 
     This buffer loading capacity is not satisfactory in the case of a leaf-stripping device that works at high speed, in particular stripping leaves from more than 2,000 plants per hour, because it does not sufficiently ease the task of the individual responsible for supplying the leaf-stripping device with tobacco plants. 
     In addition, said plants are stored one after the other without separation and therefore with the risk of sticking together under the action of the vibrations of the leaf-stripping device. 
     Also, two tobacco plants can become hooked on one another or be too close or be conveyed simultaneously toward the means for separating the leaves. 
     In this case that is depicted, either the leaf-stripping device is stopped to eliminate this operating defect, or said means for conveying or separating may be damaged. 
     It is therefore an objective of this invention to remedy the drawbacks of the devices of the prior art by proposing a device for supplying a leaf-stripping device that allows a reliable and ordered supply of tobacco plants and that facilitates the work of the individual ensuring the loading of the tobacco plants to make a leaf-stripping device work at high speed, for example at more than 2,000 plants per hour. 
     For this purpose, the invention has as its object a device for supplying a leaf-stripping device with tobacco plants, where each plant is composed of a stem bearing leaves, whereby said leaf-stripping device comprises at least one station for supplying tobacco plants, a discharging station, and means for transferring said plants from the supply station to the discharging station according to a direction of work, whereby said transfer means comprise means for receiving plants at the supply station, whereby said supply device is characterized in that it comprises means for depositing said tobacco plants on the means for receiving the leaf-stripping device, and wherein it comprises means for bringing the plants whose leaves are to be stripped one after the other and in an automated manner to the supply station of the leaf-stripping device. 
    
    
     
       Other characteristics and advantages will emerge from the following description of the invention, a description that is provided only by way of example relative to the accompanying drawings in which: 
         FIG. 1  shows a view of the supply station of a leaf-stripping device according to the prior art, 
         FIG. 2  shows a view of the discharging station of a leaf-stripping device according to the prior art, 
         FIG. 3A  shows a side view of the device for supplying tobacco plants according to the invention, 
         FIG. 3B  is a detail view of the side view of the device for supplying tobacco plants according to the invention and illustrated in  FIG. 3A , 
         FIG. 4  shows a perspective view of the device for supplying tobacco plants according to the invention, 
         FIG. 5  shows a detailed view of the area for loading the device for supplying tobacco plants according to the invention, 
         FIG. 6  shows a view of a simplified supply device for movable units in particular, 
         FIG. 7  shows a lateral elevation view of the device of  FIG. 6 . 
     
    
    
     This invention is designed for supplying a leaf-stripping device with tobacco plants P, where each device is composed of a stem T that bears leaves F. 
     More particularly, the supply device according to the invention is designed to supply a leaf-stripping device with transverse loading such as the one that is described in the preamble and shown in a more detailed manner in  FIGS. 3A and 3B . 
     Thus, such a leaf-stripping device  10  comprises at least one supply station  12  of tobacco plants P, a station  14  for discharging leaves F that are separated from stems T, means  16  for transferring said plants from the supply station to the discharging station  14 , and means  18  for separating the leaves being inserted between said supply station  12  and said discharging station. 
     The direction of movement of the tobacco plants P and more generally the direction of work is referenced S. 
     By way of example, the transfer means  16  comprise at least one carrousel  22  in the form of a closed-chain conveyor  24 , one on each side of the leaf-stripping device  10 . 
     At the supply station  12 , said carrousel  22  comprises means  23  for receiving plants P in the form of bars  26  that are arranged crosswise to the direction S and suspended by their ends, from each side, at each of the chains of the conveyor  24 , whereby these bars extend over the entire width of the leaf-stripping device  10 . 
     Each bar  26  of the receiving means  23  comprises several hooks  28  for receiving stems T of the plants P, and each bar  26  moves in the direction S for the lower strand of the chain. 
     More specifically, each hook  28  is open toward the supply station so as to receive a plant P and more particularly the stem T of this plant, whereby said plant is oriented crosswise relative to the direction of movement S, i.e., parallel to the bar  26  that supports said hooks  28 . 
     Consequently, the supply device  30  according to the invention comprises means for depositing said tobacco plants P, and more particularly their stem T, on the receiving means  23  of the transfer means  16  of a leaf-stripping device  10  with transverse loading at its supply station  12 . 
     For this purpose, the supply device  30  comprises means for bringing—in the direction S of work, corresponding to the direction of supply—the plants P whose leaves are to be stripped one after the next and in an automated manner to the supply station  12  of a transversely-loaded leaf-stripping device  10 . 
     For this purpose, and as shown in  FIGS. 3A and 3B , said means for bringing in and depositing the plants P from device  30  comprise at least one conveyor  32  with at least one supply area  34  located approximately at a supply height Ha that is suitable for depositing the plants P at the height of the receiving means  23  of the transfer means  16  of the leaf-stripping device  10 , and at least one loading area  36  with a loading height Hc that can receive several tobacco plants P simultaneously and in an ordered manner, and on which one or more operators  20  deposit the plants P. 
     Preferably, said conveyor  32  transports the plants P crosswise in the direction S of work, in particular so that said plants P arrive essentially parallel relative to the bars  26  of the receiving means  23  of the leaf-stripping device  10 . 
     To facilitate the work of the operators  20 , the loading area  36  of the conveyor  32  is placed at a height Hc that is between 0.8 and 1.2 meters corresponding to a convenient height for depositing plants P, i.e., immediately within reach of an operator  20  and so as to limit his movement of loading plants P. 
     Advantageously, as illustrated in  FIGS. 4 and 5 , the conveyor  32  offers several juxtaposed transfer locations  38 , separated from one another and driven in translation at a transfer speed V in the direction S of work. 
     The width L of each transfer location  38  and the transfer speed V are suitable for making several simultaneously accessible locations  38  within reach of an operator  20  at said loading area  36 . 
     In addition, the locations  38  have a width L that is considerably greater than the mean diameter of a stem T of a tobacco plant P. 
     To provide an estimate, a transfer location  38  has a width that is between ten centimeters and twenty centimeters, the transfer speed V is between 0.05 meter per second and 0.4 meter per second, and the loading area  36  offers about 30 transfer locations  38 . 
     Thus, in the same movement, the operator  20  can deposit several plants P in an ordered manner into said moving locations  38  of said loading area  36 , whereby each location  38  is designed to accommodate a plant P. 
     As  FIG. 4  shows, the operator(s)  20  stand(s) before the loading area  36 , and each operator  20  uses a zone  40  for supplying tobacco plants P close to the loading area  36 , and the operator(s)  20  simply has/have to transfer said plants P that are stored or are arriving at the zone  40  to the loading area  36 . 
     The supply zone  40  can correspond to a storage location or to an inlet of a supply conveyor. 
     In one preferred embodiment of the invention, the conveyor  32  transfers the tobacco plants P crosswise to the direction S of work, the transfer locations  38  therefore have their width L that is essentially parallel to the direction S of work and a length L′ that is essentially perpendicular to said direction S. 
     Advantageously, the length L′ of the transfer locations  38  of the conveyor  32  is adapted to the mean length of a stem T of a tobacco plant P, whereby said length L′ is therefore between 0.5 meter and 2 meters to provide an estimate. 
     In one preferred embodiment of the invention, the tobacco plants P are transported essentially horizontally via the conveyor  32 , whereby the transfer locations  38  are therefore essentially horizontal. 
     However, in one variant embodiment, the loading area  36  can be pitched relative to the horizontal and in a plane that is crosswise to the direction S of work, this facilitating the loading of the plants P by the operators  20  in the loading area  36 . 
     Still within a variant embodiment, the supply area  34  can also be pitched relative to the horizontal and in a plane that is crosswise to the direction S of work, this for adapting to, for example, the angle of the receiving means  23  of the leaf-stripping device  10 . 
     Still so as to facilitate the work of the operators  20 , the loading area  36  can be equipped with a stop  42  in the form of a plate  44  that is placed to the right and at one end of the length L′ of the locations  38 , whereby this stop  42  makes possible the quick positioning of the plants P on said locations  38  by defining a reference position during the loading of said plants. 
     Finally, whereby the loading height Hc can be different from the supply height Ha, an inclined area  46  connects the loading area  36  and the supply area  34  in the continuous surface of the conveyor  32 . 
     In the case that is shown in the figures where the supply height Ha is greater than the loading height Hc, the inclined area  46  is therefore ascending in the direction S of work. 
     In a preferred embodiment of the invention that is nonlimiting and illustrated in  FIGS. 4 and 5 , the conveyor  32  takes the form of at least three chains ( 48 - 1 ,  48 - 2 , and  48 - 3 ) that are essentially parallel in the direction S of work. 
     Of course, one embodiment of the conveyor  32  with one or two chains  48  can also be considered and is therefore covered by the invention. 
     Said chains ( 48 - 1 ,  48 - 2 , and  48 - 3 ) are closed and driven in a synchronized manner by at least one motor  51 , in particular electric, using suitable means for transmission and guiding such as pinions. 
     Said chains ( 48 - 1 ,  48 - 2 , and  48 - 3 ) are equipped with wedges  50  that delimit the transfer locations  38 , whereby the wedges  50  of a chain  48  are aligned with the wedges  50  of another chain  48 . 
     Thus, the wedges  50  of a chain ( 48 - 1 ,  48 - 2 , and  48 - 3 ) are uniformly spaced and define the width L of said locations  38 . 
     Advantageously, the empty volumes  52 - 1  and  52 - 2 , corresponding to the spacing intervals I 1  and I 2  between each chain ( 48 - 1 ,  48 - 2 , and  48 - 3 ) taken in the length L′ of the locations  38 , make it possible to allow the leaves F of the tobacco plants P that are transported to the locations  38  to dangle. 
     All of the elements that form said conveyor  32  rest on a frame  54  that is in particular metal and mechanically welded and able to use height-adjustable ground supports  56 . 
     Advantageously, whereby the plants P are deposited quickly on the locations  38  with width L that is considerably larger than the mean diameter of a stem T of a tobacco plant P, during the passage of the plants P at the inclined area  46  and ascending from the conveyor  32 , said plants P settle by gravity on the wedges  50  that are located to the rear of the location  38  in the direction S of work. 
     Thus, at the supply area  34  of the conveyor  32 , said plants P all arrive automatically settled on the wedge  50  behind their location  38 , uniformly spaced and in a position that is defined relative to said chains  48 . 
     This uniform and precise positioning of the plants P relative to the chains  48  that form the conveyor  32  allows controlled guiding of the supply of tobacco plants P to the leaf-stripping device  10  that is located downstream from the supply device  30 . 
     So as to supply tobacco plants P to the receiving means  23  of the leaf-stripping device  10 , at the end  58  of the supply area  34 , the conveyor  32  comprises means  60  for unloading plants P that are suitable for said receiving means  23 . 
     In a preferred embodiment, said unloading means  60  take the form of at least one downward slat  62  around which each chain  48  winds and returns at the end  58  of the supply area  34 . 
     Thus, said plants P are simply unloaded by gravity into the receiving means  23  that are joined to said slats  62 , as is illustrated in  FIG. 3B . 
     So as to guide the unloading of plants P in agreement with the operation of the leaf-stripping device  10 , and more particularly its transfer means  16 , the conveyor  32  according to the invention is equipped with at least one position sensor  64  that detects the position of wedges  50  of a chain  48  and a sensor  66  of the presence of a plant P in a location  38  at the end  58  of the supply area  34 . 
     Said presence sensor  66  is preferably located at unloading means  60  of the plants P, right at the transfer site toward the leaf-stripping device  10 . 
     Thus, using information provided by said presence sensors  66  and position sensors  64 , the motor  51  and therefore the transfer speed V of the conveyor  32  can be controlled to supply the leaf-stripping device in an optimal manner, the position sensor  64  indirectly indicating the position of the tobacco plants P because of the adjustment of said plants on the wedges  50  behind each location  38 , and the presence sensor  66  confirming that a tobacco plant P is ready to be unloaded. 
     Of course, the guiding of the transfer speed V of the conveyor  32  is also done based on the speed of the transfer means  16  of the leaf-stripping device  10  that is supplied. 
     Thus, more generally, according to the design and the operating mode of a leaf-stripping device  10  that is supplied by the device  30  according to the invention, the transfer speed V of the conveyor can be continuous or intermittent. 
     In one improved embodiment of the supply device  30  according to the invention, means for treating leaves F of plants P can be arranged along the conveyor  32  to improve the subsequent leaf-stripping, such as, for example, brushes or blowers. 
     Also, it is obvious that the supply device according to this invention can be adapted to a leaf-stripping device with longitudinal loading of tobacco plants; in particular, it is enough for suitable transfer means to be added between the supply device as it was just described and said leaf-stripping device with longitudinal loading. 
     Of course, the supply device according to this invention is not limited to the embodiment that was just described, whereby the variants that relate to the production of the conveyor  32  and location  38  are covered by the invention. Thus,  FIGS. 6 and 7  show an arrangement with a supply device that is more compact and suitable for lower speeds, more particularly for supplying movable devices that are designed to be transported to production sites so as to carry out leaf-stripping operations in situ. 
     For the description of this variant, the references of identical elements bear the same references increased by 100, except for the references that pertain to the leaf-stripping machine, which are preserved, whereby the leaf-stripping machines have only different work capacities. 
     Thus, in  FIGS. 6 and 7 , the supply device  130  comprises means for bringing into the direction S of work, corresponding to the direction of supply of a leaf-stripping machine  10 , the plants P to be stripped of their leaves one after the other and in an automated manner at the supply station  12  of a leaf-stripping device  10  with transverse loading. 
     For this purpose, and as shown in  FIGS. 6 and 7 , said means for bringing in and depositing the plants P of the device  130  comprise at least one conveyor  132  with at least one supply area  134  that is located essentially at a supply height Ha that is suitable for depositing the plants P at the height of the receiving means  23  of the leaf-stripping device  10 , and at least one loading area  136  of loading height Hc that can receive several tobacco plants P simultaneously. 
     Preferably, said conveyor  132  conveys the plants P crosswise in the direction S of work, in particular so that said plants P reach—essentially parallel relative to the bars  26 —receiving means  23  of the leaf-stripping device  10 , as above. 
     The loading area  136  of the conveyor  132  is arranged at a height Hc of between 0.8 and 1.2 meters corresponding to a convenient height for depositing plants P, as in the preceding variant. 
     Advantageously, as illustrated in  FIGS. 6 and 7 , the conveyor  132  offers several juxtaposed transfer locations  138 , separated from one another, and driven in translation at a transfer speed V in the direction S of work. 
     In the case that is shown in the figures where the supply height Ha is greater than the loading height Hc, the inclined area  146  is therefore ascending in the direction S of work. 
     The chains, wedges  150  are identical to the preceding embodiment. 
     All of the elements that form said conveyor  132  rest on a frame  154  that is in particular metal and mechanically welded and able to be made integral with the leaf-stripping device  10  with a height adjustment. 
     This arrangement makes it possible to move an entire leaf-stripping device unit that is equipped with wheels by rolling from one operation to the next, but also to connect a supply so that even in smaller operations, working comfort is preserved.