Patent Publication Number: US-2019193978-A1

Title: Self-aligning detector device

Description:
TECHNICAL FIELD 
     The invention relates in particular to a mailpiece sorting machine having sorting outlets with storage devices, each storage device including a recess into which a receptacle comes to be inserted, in which receptacle the sorted mailpieces are stored. 
     PRIOR ART 
     Such a type of machine is used more particularly in postal sorting centers for sorting parcels. 
     The receptacle of each sorting outlet is generally in the form of a wheeled bin having quite large dimensions. 
     In order to insert the bin into the recess, an operative wheels it to the far end of the recess into an abutment position. 
     The switching flap of each sorting outlet should be placed in the position in which it diverts parcels to the bin only when said bin is correctly pushed into the recess. 
     It has already been observed that the positioning of the bins can vary to a certain extent, it being possible for certain bins to be misaligned relative to the recess. 
     There therefore exists a need for a sensor that makes it possible to detect the presence of the bin in the recess so as to cause the switching flap to pivot. 
     In particular, the sensor should allow for a certain amount of tolerance in the positioning of the bin in the recess, while also reliably detecting the correct positioning of the bin in the recess so as to avoid a parcel being able to fall to the floor outside the bin. 
     Patent application US 2007/0072656 describes an electronic device that can be folded closed by two elements pivoting relative to each other, one of the elements including a magnetic detector. 
     SUMMARY OF THE INVENTION 
     To this end, the invention provides a detector device comprising an activator element and a detector element that are mounted to move relative to each other, the detector element generating a detection signal by a proximity effect when the activator element is facing it, said detector device being characterized in that it further comprises a swing system with a first lever carrying the detector element and a second lever carrying the activator element, said levers being mounted on a common pivot while being offset angularly from each other, the second lever being designed to pivot from a rest position towards the first lever under the effect of thrust and to move angularly closer to the first lever until it reaches a state of alignment in which the activator element and the detector element are in alignment, and in that said first and second levers are designed such that, starting from the state of alignment and under the effect of the thrust, the second lever causes the first lever to pivot through a certain angular range. 
     With this self-aligning device mounted on the far end plane of the recess, in such a manner that the front face of the bin comes to exert thrust on the second lever when the bin is inserted into the recess, it is possible to obtain reliable detection of the presence of the bin in the recess and in the correct position for receiving the parcels. 
     In particular, it can be understood that the angular offset of one lever relative to the other requires the bin to be inserted sufficiently deeply into the recess and, at the same time, the possibility for the two levers to pivot through the angular range affords a certain amount of tolerance in the positioning of the bin in the recess, e.g. so that the bin can be positioned askew in the recess. 
     With this machine, operatives are kept safe without a large amount of investment, by small modifications being made to the equipment, and without any impact on the usual working methods, in particular on the type of receptacles used and on the way in which they are handled; even if the receptacles that are usually used have dimensions and shapes that are poorly defined, and are positioned under the flaps in approximative manner, their presence and their absence can be detected reliably, preventing the flaps from opening at times when that could be dangerous for the operatives and/or could adversely affect the sorting operations. 
     In addition, by means of the configuration of the detector device, this machine can advantageously use conventional proximity detectors that are reliable, robust, and inexpensive, but that, ordinarily, can be used only for very well defined geometrical shapes, such as, for example, to detect closing of a door. 
     The invention may advantageously also have the following features:
         an abutment may be provided to maintain the first lever angularly offset from the second lever in the rest position;   the second lever may be provided with a tab that is designed to come to bear against the first lever to cause it to pivot through said certain angular range;   the second lever may be urged to return towards its rest position by a return spring;   another abutment may be provided to stop the pivoting of the first lever at the maximum limit of said certain angular range;   said second lever may hang substantially vertically in the rest position; and   the proximity effect may be a magnetic effect.       

     The invention may also provide:
         a storage device that may include a frame forming a recess having a far end plane and into which a storage receptacle can be inserted, said storage device being characterized in that it includes a detector device of the invention, said detector device being mounted on the far end plane of the recess, said receptacle having a front face suitable for exerting said thrust on the second lever when the receptacle is inserted in the recess; and   a mailpiece sorting machine characterized in that it may include sorting outlets, each of which has a storage device of the invention, and a switching flap for diverting mailpieces into the storage device, the flap being controlled on the basis of said detection signal.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be better understood and other advantages appear on reading the following detailed description of an embodiment given by way of non-limiting example and with reference to the accompanying drawings, in which: 
         FIG. 1A  is a diagrammatic fragmentary view of an example of a sorting machine of the invention with receptacles in the loading positions; 
         FIG. 1B  shows a detector device of the invention, how it is incorporated into the sorting machine of  FIG. 1A , and how it is positioned relative to a receptacle; 
         FIG. 2A  is a perspective view of the detector device of  FIG. 1B ; 
         FIG. 2B  shows how the detector device of  FIG. 1B  operates; 
         FIG. 3  is a block diagram showing the functional relationships between the elements that operate the sorting machine that is shown in  FIG. 1A  and that includes the detector device  1 B; and 
         FIG. 4  is a fragmentary view of a storage device of the invention, and of how the detector device of  FIG. 1B  is incorporated into this storage device. 
     
    
    
     DESCRIPTION OF AN EMBODIMENT 
     A mailpiece sorting machine  100  including a storage device  105  and a detector device of the invention is shown in  FIGS. 1A to 4 . 
     Ordinarily, the sorting machine  100  shown in  FIG. 1A  is incorporated into a sorting installation in which mailpieces to be sorted are received, and then disposed on a conveyor that brings them to a sorting conveyor  122  that is incorporated into the sorting machine  100  and that has sorting outlets  125 . 
     During operation, operatives put receptacles  130  into loading positions in the storage device  105  under the sorting conveyor  120 , towards which receptacles the sorting machine directs the mailpieces to be sorted that are brought to it. 
     The receptacles  130  are suitable for being changed during the sorting, and they may be wheeled trolleys such as the ones shown in  FIGS. 1A and 1B , or any other container suitable for receiving objects, such as cardboard boxes, dropping from the conveyor. 
     In order to ensure that the sorting operations take place properly and also for safety reasons, a sorting machine of the invention includes detector devices  200  that make it possible to detect whether or not receptacles are present under the sorting conveyor  120 . 
     The sorting conveyor  122  is made up of flaps  125 , each of which comprises a conveyor belt  126  for conveying the mailpieces and for keeping the sorting outlets  125  closed when the respective flaps are in the closed position. 
     Each of the flaps  125  can pivot to an open position to form an opening  127  in the conveyor  120  in such a manner as to allow mailpieces to drop under the sorting conveyor  122 , into the corresponding receptacle  130 . 
     A frame  110  forms the storage device  105  that can support the sorting conveyor  122  and that defines a recess  135  for a receptacle under each of the flaps  125 , in such a manner that each receptacle  130  put in the loading position in one of the recesses can receive parcels dropping from the sorting conveyor  120  after the flap  125  overlying it has been opened. 
     The flaps are controlled by a monitoring and control system  260  that is configured to open and to close the flaps in compliance with a sorting plan that indicates an outlet, and therefore a destination receptacle, for each mailpiece to be sorted. 
     For example, the sorting plan may be recorded in a computer memory  265  that is in functional communication with the monitoring and control system. 
     The monitoring and control system is also functionally connected to the detector devices  200  for detecting the presence of the receptacles under the flaps, and has a safety function that consists in stopping from opening each flap under which the presence of a receptacle in the loading position is not detected. 
     Each detector device  200  is incorporated into a far end plane ( 136 ) of a recess of the storage device  105 , and is configured to send detection signals to the monitoring and control system indicating that the presence of a receptacle in said recess has been detected. 
     Each flap is associated with one of the detector devices, each of which is fastened to a fastening plate  240  mounted on an element  115  of the frame in the far end plane of a recess and extending in such a manner as to be adjacent to the front faces  132  of receptacles in the loading positions in the recesses  135 . 
     The detector devices are also configured in such a manner that a receptacle put in place in a recess by pushing on its rear face  133  causes a detection signal to be sent by one of the detector devices. 
     A detector device  200 , shown in  FIGS. 1B, 2A, and 2B , is based on using a conventional proximity sensor that is made up of two elements  210  and  220  that are, respectively, a detector element  210  and an activator element  220  having the function of activating the detector element by a proximity effect when the two elements are facing each other a short distance apart. 
     For example, the proximity effect of such a sensor may be a magnetic effect, a capacitive effect, or an inductive effect. 
     The two elements of the sensor are mounted on a swing system having two levers, the detector element being mounted on a front face  212   a  of a first lever  212  and the activator element being mounted on a front face  222   a  of a second lever  222 . 
     The two levers are arranged to pivot about a common pivot axis  230 , or pivot  230 , mounted transversely on the fastening plate  240 , the first lever  212  being interposed between the fastening plate and the second lever  222 . 
     The two elements of the proximity sensor are situated substantially at the same distance from the pivot, and the levers are close enough together for the activator element to activate the detector element when they are facing each other. 
     The plate  240  and the axis  230  are situated and oriented in such a manner that putting a receptacle into place in a loading position in any given recess causes the levers of the corresponding detector device to be driven in rotation R by thrust P, as indicated in  FIGS. 1B and 2B . 
     A first abutment  216  and a second abutment  217  extend parallel to the axis  230  from the plate  240 , and are long enough to stop movement in rotation of at least the first lever, the first abutment  216  being short enough so as to not to stop movement in rotation of the second lever. 
     When the device is in a rest state Er, said levers are offset angularly from each other, as can be seen in  FIGS. 1B and 2B . 
     More precisely, the first lever  212  is inclined, its rear face  212   b  being in contact with the first abutment  216  that stops its movement in rotation, while the second lever  222  is in a rest position that is lower than the first lever, e.g. so that said second lever hangs substantially vertically from the pin  230 . 
     When the device is in the state Er, and because of the angular offset between the levers due to the abutment  216 , the two elements of the sensor are in a state of non-alignment, i.e. they do not face each other, and the activator element cannot activate the detector element. 
     A drive tab  224  extends from the second lever and is configured so that the second lever  222  drives the first lever  212  in rotation by pushing it on its rear face  212   b.    
     More precisely, the drive tab  224  extends towards the fastening plate  240  from a side  222   c  of the second lever  212  that faces the fastening plate  240 , in such a manner as to come into contact with the rear face  212   b  of the first lever  212 . 
     The tab  224  is provided with a shoulder so that, when the tab is in contact with the rear face of the first lever  212 , the two levers are aligned with each other, or are superposed, as seen looking along the pin  230 , and the two elements  210  and  220  of the sensor are also aligned with each other and face each other. 
     When the device is in a state Emax, the front face  212   a  of the first lever is in contact with the second abutment  217  and its rear face  212   b  is in contact with the drive tab  224  of the second lever. 
     In the state Emax, the levers  212  and  222  and the elements  212  and  222  of the sensor are mutually aligned, respectively,  FIG. 2B  showing the state when, in the view of the figure, the levers and the elements of the sensor, in dashed lines, are superposed. 
     An actuator member  226  extends from the second lever  222  rearwards from it into the volume of a recess  135 , the actuator member being designed in such a manner as to transmit to the second lever  222  thrust P from a receptacle  130  put in place in said recess. 
     The actuator member may have any shape whatsoever, but it is preferably adapted to the type of receptacle that is used, and is not limited to the shape shown in the figures. 
     The state Emax corresponds to an amplitude of maximum rotation of the levers that is obtained after thrust has been exerted on the second lever  222  and after the first lever  212  has been driven in rotation by the drive tab  224  of the second lever  222 . 
     A return spring  250  may be fastened between the fastening plate  240  and the second lever  222  in such a manner as to return said second lever to the low position after it has been moved by the thrust P of the receptacle  130 . 
     The spring is not strictly necessary for the second lever  222  to return to the low position, gravity alone normally being sufficient to bring the lever back to this position, but the spring provides a backup if an unforeseen or undetected difficulty arises, such as, for example, movement in rotation about the pivot axis  230  being prevented by corrosion, making gravity alone insufficient for pivoting the lever into its rest position. 
     A tab  225  may extend from the fastening plate  240  to impose a given rest position to the second lever  222 . 
     A third abutment  140 , fastened to the element  115  of the frame, extends horizontally at the far end of each of the recesses  135  to stop the receptacles  135  from advancing any further when they are pushed into the recesses in order to be put into loading positions under the flaps, in such a manner as not to bring the first lever and/or the second lever into contact with the second abutment  217  by direct thrust, which could damage the device. 
     The second abutment  217  serves to stop the movement in rotation of the first lever  212  in the event it continues to move in rotation by an inertia effect after a receptacle has been put into place in a recess, and thereby prevents pinching of an electrical power and/or monitoring cable  219  extending from the detector element  210  and passing through an opening  245  in the fastening plate  240 . 
     During operation, in the situation in which the recess of the given receptacle is empty, the corresponding detector device is in the rest state Er, the elements of the detector  200  are in the non-aligned state, no detection signal indicating detection of the presence of a receptacle is sent, and the corresponding flap is locked in the closed position. 
     Starting from this situation, when a receptacle  130  is put in place manually by an operative in a recess  135 , the receptacle pushes the second lever  222  of a given detector device  200  via its actuator member  226 , and causes it to pivot from its rest position so that it moves angularly closer to the first lever  210  until a state of alignment is reached in which the activator element and detector element are in alignment. 
     The first and second levers are designed so that, starting from this state of alignment, and under the effect of the thrust, the second lever causes the first lever to pivot through a certain angular range. 
     More particularly, while the second lever  222  is moving in rotation, the tab  224  comes into initial contact with the first lever  212  that is in contact with the abutment  216 , and then drives said first lever in rotation when the second lever continues to move in rotation. 
     Starting from the initial contact and so long as the contact between the tab and the first lever is maintained, the two elements  210  and  220  of the sensor are aligned with each other, and a receptacle detection signal is sent to the monitoring and control system that responds by authorizing opening of the flap corresponding to the given detector device. 
     An order to open the flap is sent to the sorting machine by the monitoring and control unit only if the following two conditions are satisfied simultaneously: 1) a detection signal indicating that a receptacle has been detected is received and 2) a parcel to be caused to drop into said receptacle arrives at the corresponding flap. 
     In this way, the absence of a receptacle in any given recess stops the corresponding flap from being opened, thereby firstly ensuring that the sorting operations take place properly and secondly preventing any risk related to movement of the flap for the operatives who, in the absence of the receptacle, have direct access to the flap. 
     A receptacle detection signal may be sent continuously so long as the detector element and the activator element are mutually aligned, or a plurality of detection signals may be sent at time intervals that are short enough for withdrawal of the receptacle to be detected quickly enough not to have any impact on the sorting operations and/or not to compromise the safety of the operatives. 
     Since the drive tab maintains the two detector elements in alignment through a certain angular range of rotation of the levers, or indeed through a range of rotation of the second lever as pushed by the receptacle, the detection signal indicating the receptacle has been detected can be sent independently of the exact position of the receptacle in its recess, when the device is in any state whatsoever between a state in which the initial contact takes place between the tab  224  and the first lever  212  in contact with the abutment  216  and the state Emax in which the amplitude of maximum rotation of the levers is reached. 
     Thus, the above-described mechanical device enables two elements making up a proximity detector to be aligned automatically, thereby constituting a self-aligning detector device. 
     When the receptacle is withdrawn from its recess in order to be replaced, gravity and the spring  250  return the device to its state Er, thereby interrupting sending of a positive detection signal indicating that the receptacle has been positively detected, and the flap is locked in the closed position until a receptacle is again placed in the recess as described above.