Abstract:
A device ( 10 ) for loading containers ( 12 ), which are provided with a neck ( 20 ), on an transporting element ( 14 ) includes a member ( 28 ) for individually grasping the container by the neck thereof, wherein the grasping member is used for catching or releasing the neck of a preform by the vertical slide of the preform with respect to the grasping member during an operation for catching or releasing it, the loading device includes elements ( 42, 68 ) for selectively ejecting the container from the transporting element during the releasing operation. The elements for ejecting the container are provided with container receiving members ( 42 ) which are used for catching the container prior to the releasing operation and are mounted in a horizontally movable manner in such a way that the trajectory of the receiving members are vertically superimposed and synchronized with the trajectory of the grasping device.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a device for loading containers that include a neck onto a transporting element. 
     The invention relates more particularly to a device for loading containers with a vertical axis comprising an upper neck, and in particular preforms made of thermoplastic material, onto a transporting element which comprises at least one individual member for grasping a container by its neck and which is able to transport the preform along a horizontal transport path, of the type in which the grasping member is able to catch or release the neck of the preform by vertically sliding the preform into a grasping position relative to the grasping member in an operation for grasping or releasing the preform, the loading device comprising means for selectively ejecting the container from the transporting element, when the container is incorrectly held by the individual grasping member after the grasping operation, in a releasing operation. 
     The present invention relates to refinements made to devices for loading containers or preforms having a neck, notably bottles, onto a transporting element which is equipped with individual members for grasping containers by their neck. These grasping members are spaced apart from each other by a predetermined pitch and the containers are brought to the loading device one after the other spaced apart by the predetermined pitch. 
     These loading devices are in particular suited to container production and/or filling installations. Thus, in container production installations, preforms are transported by such a transporting element through a preheating oven before the duly heated preforms are transformed into containers by a blow-molding operation. 
     In this type of installation, it happens that containers, and in particular preforms, are incorrectly held or caught by the grasping member of the transporting element. The preform then risks falling from the transporting element during its travel. 
     To avoid this problem, it is known that the incorrectly held preforms must be ejected at the start of the travel in order for the preforms not to fall in places that can threaten the operation of the installation, for example inside an oven. 
     However, in the known installations, the preforms are ejected with little precision, which entails providing a fairly wide ejected-preform recovery area. 
     SUMMARY OF THE INVENTION 
     To solve this problem, the invention proposes a loading device which comprises means for ejecting incorrectly held preforms that make it possible to eject the preforms more accurately, and which is characterized in that the means for ejecting the container comprise means of receiving the container which are able to catch the container prior to the releasing operation and which are mounted to move horizontally so that the path of the reception means is vertically superimposed and synchronized with the path of the grasping member. 
     According to other characteristics of the invention:
         the ejection means comprise means for controlling the expulsion of the container from the reception means after the releasing operation;   the reception means comprise a clamp which is able to catch the container by its neck by reversible elastic fitting of the preform in the clamp;   the device comprises an obstacle which is positioned on the path of the lower body of the container carried by the clamp downstream of the operation for releasing the container, so that the container is stopped in its path by the obstacle while the clamp continues its path, causing the preform to be separated from the clamp;   the reception means are mounted to slide vertically relative to the grasping member between atop position in which the container carried by the clamp is held by the grasping member, and a bottom position in which the container is released from the grasping member, the device comprising means for selectively sliding the reception means downward when the container is incorrectly held in order to provoke the operation for releasing the container, the reception means being maintained in the bottom position at least until the container is expelled by the obstacle;   the reception means comprise a cam follower which is able to cooperate with a cam path which is fixed relative to the reception means and which drives the reception means by sliding to their bottom position in the releasing operation, the cam path including an upstream switching section which is mounted to move between a retracted position in which the reception means which are not oriented towards the cam path remain in the top position, and an active position in which the switching rail directs the cam follower to the cam path in order to selectively drive the reception means to their bottom position;   the switching rail is mounted to pivot relative to the cam path by one of its upstream or downstream ends between its retracted position and its active position;   the switching rail is mounted to slide relative to the cam path between its retracted position and its active position;   the switching rail is mounted to slide in a vertical direction;   the switching rail is mounted to slide in a horizontal direction perpendicular to the path of the reception means.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages will become apparent while reading the detailed description that follows, for an understanding of which the reader should refer to the appended drawings in which: 
         FIG. 1  is a plan view which represents a loading and unloading device which is produced according to the teachings of the invention; 
         FIG. 2  is a larger-scale side view which represents preforms which are caught by mandrels carried by a transport chain; 
         FIG. 3  is a view similar to that of  FIG. 1  on a larger scale which represents an area for loading preforms onto the transport chain; 
         FIG. 4  is a diagrammatic side view which represents preforms during the grasping operation by the mandrels; 
         FIG. 5  is a view similar to that of  FIG. 4  which represents the path of a preform which is incorrectly held by a mandrel. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the description hereinbelow, a longitudinal, vertical and transversal orientation indicated by the trihedron L,V,T of  FIG. 1  will be used in a non-limiting way. 
     Hereinafter, identical, analogous or similar elements will be designated by the same reference numbers. 
       FIG. 1  represents a device  10  for loading containers  12  onto a transporting element  14 . 
     The containers  12  are in this case preforms which are made of a thermoplastic material, such as polyethylene terephthalate (PET), and which are intended to be transformed into containers, such as bottles, after a first heating operation to soften the constituent thermoplastic, then a second blow-molding or stretch blow-molding operation, to shape the preform  12  into a container. 
     In a known way, each preform  12  has the form of a test piece or test tube of vertical axis “A”. As represented in  FIG. 2 , the tubular body  16  of the preform  12  is closed at its bottom end by a hemispherical bottom  18  whereas its top end has a neck  20  which forms the neck of the final container. 
     The junction between the tubular body  16  and the neck  20  is delimited by a collar  22  which extends horizontally projecting externally. The external cylindrical face  20  of the neck in this case comprises a screwthread which is intended to receive a threaded top (not represented) in order to seal the container. 
     The element  14  for transporting the preforms  12  is in this case a flexible element such as an endless transport chain which forms a closed loop extending in a horizontal plane. As represented in  FIG. 2 , the transport chain  14  comprises a plurality of links  24  which are hinged relative to each other by hinges  26  of vertical axis “B”. 
     The transporting element  14  comprises a plurality of grasping members  28  which are in this case mandrels. Each mandrel  28  is carried by a link  24  of the transport chain  14 . The mandrels  28  are spaced apart by a predetermined pitch “S” which in this case corresponds to the distance between the hinges  26  of a link  24 . 
     Each mandrel  28  is more particularly carried by a rod  30 , also called spinner, of vertical axis “C” which extends vertically downward from the middle of a bottom face of the link  24 . 
     The bottom end of each rod  30  carries the mandrel  28  which comprises a plurality of jaws (not represented) which move radially relative to the axis “C” of the mandrel between a retracted position in which the mandrel  28  is able to be inserted inside the neck  20  of a preform  12 , and an expanded position in which the jaws are able to exert a radial pressure against the internal cylindrical wall of the neck  20  of the preform  12  in order for the preform  12  to be secured by friction to the mandrel  28 . The jaws are elastically returned to their expanded position. 
     Thus, in an operation for grasping the preform  12  by the mandrel  28 , the mandrel  28  is inserted by force vertically inside the neck  20  of the preform  12  by vertical sliding relative to the mandrel  28  in relation to the preform  12 , which provokes a retraction of the jaws against the elastic return force. 
     In the embodiment represented in  FIGS. 2 ,  4  and  5 , the rod  30  is mounted to rotate about its axis “C” relative to the link  24  in order to be able to rotate the preform  12  on itself about the axis “C” when it is transported by the transport chain  14 . 
     As represented in  FIG. 1 , the transport chain  14  is in this case driven rotationwise or at least guided rotationwise, by a drive wheel  32 . The drive wheel  32  is mounted to rotate about its vertical central axis “D” and it is driven rotationwise in an anticlockwise direction with reference to  FIG. 1 . 
     A curved portion  14 A of the transport chain  14  is wound around a peripheral rim portion  34  of the drive wheel  32 . The curved portion  14 A of the transport chain  14  here forms a semicircle. 
     The transport chain  14  also comprises a downstream rectilinear portion or downstream strand  14 B which is positioned tangentially to the drive wheel  32  downstream of the curved portion  14 A in the anticlockwise direction of rotation of the transport chain  14 . 
     The transport chain  14  also comprises an upstream rectilinear portion or upstream strand  14 C which is positioned tangentially to the drive wheel upstream of the curved portion  14 A in the anticlockwise direction of rotation of the transport chain  14 . 
     The transport chain  14  is able to transport in turn each preform  12  carried by a mandrel  28  from an input point “P 1 ” where the preform  12  is taken by the mandrel  28 , to an output point “P 2 ” where the preform  12  is released from the mandrel  28 , along a transport path, passing through at least one heating area (not represented). 
     In order for the predetermined pitch “S” between the mandrels  28  to be the same all along the transport chain  14 , both on the rectilinear strands  14 B,  14 C and on the curved portion, the axis “C” of the mandrels and the axis “B” of the hinges follow a single common path along the chain. 
     The loading device  10  comprises means of supplying preforms  12  which are intended to route the preforms  12  one after the other to the transport chain  14  via means of distributing preforms  12  to the grasping members  28  which will be described in more detail hereinafter. 
     The supply means in this case comprise a guideway  36  and an input transfer wheel  38  which is mounted to rotate about its vertical central axis “E”. 
     The input transfer wheel  38  comprises notches  40  for receiving necks  20  of the preforms  12  which are spaced apart from each other circumferentially by the predetermined pitch “S”. These notches  40  are able to receive the necks  20  of the preforms  12  arriving via the guideway  36  and to support the preforms  12  using their projecting collar  22  which bears on the edge of the notches  40 . 
     Thus, the guideway  36  successively guides each preform  12  to the input transfer wheel  38  so as to distribute each preform  12  in an associated notch  40 . 
     The notches  40  of the input transfer wheel  38  are here positioned at a height less than that of the mandrels  28  of the transport chain  14 . 
     As represented in  FIG. 1 , in planar projection, the input transfer wheel  38  is here positioned tangentially to the curved portion  14 A of the transport chain  14  at a first point of intersection “P 3 ”. 
     The input transfer wheel  38  is driven rotationwise about its axis “E” in a clockwise direction with reference to  FIG. 1 . The rotation speed of the input drive wheel  38  is synchronized with the rotation speed of the transport chain  14  so that a grasping member  28  and a notch  40  of the input transfer wheel  38  present themselves in synchronism at the first point of intersection “P 3 ” in line with one another. 
     According to the teachings of the invention, the loading device  10  also comprises means of distributing preforms  12  which are in particular intended to maintain the preforms  12  during the grasping operation by the mandrels  28 . 
     To this end, the drive wheel  32  comprises reception means  42  such as clamps as shown in  FIG. 3 . Here they are rigid clamps  42 , the jaws of which, which are immobile relative to each other, delimit a recess of a shape complementing the shape of the neck  20  of each preform  12 . Since the preforms  12  are made of an elastically deformable material, the neck  20  of the preform is elastically fitted reversibly between the jaws of the clamp  42 . 
     According to a variant that is not represented of the invention, the clamps  42  have jaws which are articulated between a closed position and an open position, the jaws being returned elastically to their closed position. 
     According to a variant that is not represented of the invention, the clamps are carried by a plate of axis coaxial to the axis “D” of the drive wheel  32 . 
     The clamps  42  are distributed over all the circumference of the drive wheel  32 , roughly at the same height as the notches  40  of the input drive wheel  38 . The clamps  42  are circumferentially separated from each other by the predetermined pitch “S” so that a clamp  42  is axially positioned under each mandrel  28  of the curved portion  14 A of the transport chain  14 . 
     Thus, in planar projection, the circular path of the clamps  42  is superimposed on the path of the mandrels  28  all along the curved portion  14 A of the transport chain  14 . In other words, in planar projection, the path of the mandrels  28  is the same as the path of the clamps  42  all along the curved portion  14 A of the transport chain  14 . 
     As represented in  FIG. 4 , each clamp  42  is intended to receive a preform  12  and to support this preform at least during the operation for grasping the preform  12  by the mandrel  28 . 
     Each jaw of the clamp  42  comprises a groove which extends radially relative to the axis “A” of the preform in the internal wall of the jaw in order to receive the collar  22 . The preform  12  is thus supported by the horizontal bottom wall of the groove. The horizontal top wall of the groove immobilizes the upward movements of the preform  12  relative to the clamp  42 . Thus, when the collar  22  is received in the complementary groove of the clamp  42 , the preform  12  is immobilized against vertical movement in both directions relative to the clamp  42 . 
     Each clamp  42  passes the first point of intersection “P 3 ” of the input transfer wheel  38  and of the transport chain  14 , in synchronism with a notch  40  of the input transfer wheel  38 . Since the clamps  42  are positioned substantially at the same height as the notch  40 , the clamp  42  is able to catch under its collar  20  the preform  12  carried by the notch  40 . The preform  12  is thus transferred from the input transfer wheel  38  to the drive wheel  32 . 
     When the preform  12  is caught by the clamp  42 , it occupies a so-called grasping position in which the axis “A” of the preform  12  is coaxial to the axis “C” of the mandrels  28 , the mandrels thus being arranged facing the neck  20  of the preform  12 . 
     The first point of intersection “P 3 ” is positioned on the curved portion  14 A of the chain  14 , upstream of the input point “P 1 ” which is positioned on the curved portion  14 A of the chain  14  downstream of the first point of intersection “P 3 ”, for example at the downstream end of the curved portion  14 A. Thus, the grasping operation advantageously lasts for the time it takes for the clamp  42  to travel an angular segment “P 3 -P 1 ” of angle “a”. 
     The path of the preform  12  carried by the clamp  42  and that of the mandrel  28  are superimposed along the angular segment “P 3 -P 1 ” which forms, in planar projection, a first line of intersection between the path of the mandrels  28  and that of the clamps  42 . 
     Thus, between the first point of intersection “P 3 ” and the start point “P 1 ”, the preform  12  is maintained by the clamp  42  in its grasping position at right angles to the mandrel  28 . 
     According to another aspect of the invention, the operation for grasping the preform  12  by the mandrel  28  requires a vertical sliding movement of the preform  12  into the grasping position relative to the mandrel  28 . 
     According to the teachings of the invention, the clamps  42  are advantageously mounted to slide vertically relative to the drive wheel  32  between a bottom transfer position in which the clamp  42  is positioned at the same height as the notches  40  of the input transfer wheel  38  and a top loading position in which the neck  20  of the preform  12  carried by the clamp  42  is at the same height as the mandrels  28  so that the mandrel  28  is fitted into the neck  20 . 
     As represented in  FIG. 4 , the vertical sliding of each clamp  42  is here controlled by a cam system. Thus, each clamp has a cam follower which comprises a control rod  44 . A roller  46  is mounted to rotate at a free bottom end of the control rod  44  of each clamp  42 . 
     The roller  46  is intended to cooperate with a cam path  47  which is here carried by the bottom surface of a grasping rail  48 . The grasping rail  48  is fixed relative to the drive wheel  32 , that is, the grasping rail  48  is not driven rotationwise by the drive wheel  32 . 
     Furthermore, each clamp  42  is elastically returned to its top loading position by a return spring  50 , so that it is not necessary to prolong the rail when the clamp  42  is in the top loading position. 
     The cam path  47  comprises a first upstream slope  52  which is intended to control the lowering of the clamp  42  to its bottom transfer position. The cam path  47  also comprises a second downstream slope  54  which is intended to control the raising of the clamp  42  to its top loading position. 
     The second upstream slope  54  here extends over at least a portion of the line of intersection corresponding to the angular segment of angle “a”, so that the grasping operation can be performed for a long enough time to ensure a reliable fitting of the mandrel  28  inside the neck  20  of the preform  12 . 
     According to yet another aspect of the invention represented in  FIG. 5 , the loading device  10  comprises means for ejecting a preform  12  when it is not correctly caught by the mandrel  28 , for example when the preform  12  is likely to fall on its path along the transport chain  14 . 
     In this case, the start point “P 1 ” of the preforms is arranged upstream of the downstream end of the curved portion  14 A of the transport chain  14 , so that the clamps  42  are able to temporarily support the preforms  12  after they have been taken by the mandrel  28  to the end of the curved portion  14 A of the transport chain  14 . 
     To this end, the loading device  10  comprises a sensor (not represented) for detecting the preforms  12  that are incorrectly fitted. The sensor is arranged so as to detect a fitting fault when the clamp  42  is in the top loading position, that is, when the preform  12  is caught by the mandrel  28  and its neck  20  is still supported by the clamp  42 . 
     The ejection means also comprise a second ejection rail  64  which comprises a cam path and, more specifically, a downward slope so as to maintain the clamp  42  in the bottom transfer position against the force exerted by the return spring  50  when the preform  12  is incorrectly fitted. 
     In order to selectively engage the clamps  42  carrying a preform  12  that is incorrectly fitted to the ejection rail  64 , the device  10  comprises a retractable switching rail  66  which is mounted to move between a retracted position in which it is not inserted in the path of the roller  46  so that the clamp  42  remains in the top grasping position, and an active position in which the retractable switching rail  66  is inserted into the path of the roller  46  so as to direct the roller  46  under the ejection rail  64  in order to lower the clamp  42  to its bottom transfer position. 
     When the retractable switching rail  66  is in the active position, the clamp  42  is returned to its bottom transfer position by the ejection rail  64  while separating the neck  20  from the mandrel  28 . 
     The retractable switching rail  66  is in this case a portion of rail which is mounted to pivot relative to its upstream end. 
     According to a variant of the invention, the retractable switching rail  66  is a portion of rail that is mounted to slide vertically between a retracted top position and an active bottom position. 
     According to yet another variant of the invention, the retractable switching rail  66  is a portion of rail which is mounted to slide radially relative to the axis “D” of the drive wheel  32 , between a retracted external lateral position and an active internal insertion position. 
     When the preform  12  that is incorrectly fitted or incorrectly held is once again in its bottom transfer position, it is released from the clamp  42  to leave the device  10  and the installation  14 . The preform  12  is, for example, released from the clamp  42  when it is no longer located under the transport chain  14 , after the paths of the clamps  42  and of the mandrels  28  have diverged. 
     To this end, the device comprises an obstacle such as a first arm  68  which is inserted in the path of the body  16  of the preform  12  when the latter has been switched to its bottom transfer position by the retractable switching rail  66 . The arm  68  is here a plate which makes it possible to release the preform  12  from the grip of the clamp  42  by provoking the separation of the preform  12  from the clamp  42 . 
     As represented in  FIG. 1 , the installation also comprises an unloading device  58  which is similar to the loading device  10 . Thus, the unloading device  58  comprises an output transfer wheel  60  and an output guideway  62 . 
     The output transfer wheel  60  is positioned at the same height as the input transfer wheel  38 , and it comprises notches  40  identical to those of the input transfer wheel  38 , and it is mounted to rotate in a clockwise direction about an axis “F” tangentially to the drive wheel  32  at a second point of intersection “P 4 ”. 
     The clamps  42  of the drive wheel  32  are able to catch the preforms  12  carried by the mandrels  28  at an arrival point “P 2 ” which is here positioned at the upstream end of the curved portion  14 A of the transport chain  14 . 
     The rotation speed of the output transfer wheel  60  is also synchronized with the rotation speed of the drive wheel  32  so that a notch  40  of the output transfer wheel  60  passes in synchronism with a clamp  42  of the drive wheel  32  at the second point of intersection “P 4 ” which is positioned downstream of the arrival point “P 2 ”. 
     In planar projection, the path of the clamps  42  and the path of the mandrels  28  are superimposed on a second line of intersection “P 2 -P 4 ” which extends between the arrival point “P 2 ” and the second point of intersection “P 4 ”. 
     The second point of intersection “P 4 ” is more particularly positioned upstream of the first point of intersection “P 3 ” relative to the direction of rotation of the drive wheel  32 . 
     Thus, between the moment at which the preform  12  is caught at the point “P 3 ” by a clamp  42  and the moment at which the preform is transferred to the output transfer wheel  60  at the second point of intersection “P 4 ”, the preform  12  is maintained by the clamp  42  in line with the associated mandrel  28 . 
     In a releasing operation which extends along the second line of intersection “P 2 -P 4 ”, the preform  12  is released from the grip of the mandrel  28  by a progressive downward vertical sliding movement of the clamp  42  which begins substantially at the arrival point “P 2 ” and which ends roughly at the second point of intersection “P 4 ”. 
     The unloading device  58  comprises a second arm (not represented) which is able to release the preform from the grip of the clamp  42 . 
     Advantageously, the same clamps  42  are therefore used successively to maintain the preforms in the grasping position in the grasping operation, then in the releasing operation. 
     In the operation of such a heating installation, the preforms  12  are routed one behind the other by the guideway  36  to each notch  40  of the input transfer wheel  38 . Then, the input transfer wheel transports each preform  12  to the first point of intersection “P 3 ” with the transporting element  14 . 
     A clamp  42  which is driven by the grasping rail to its bottom transfer position then automatically catches the preform  12  so as to maintain the preform  12  vertically under an associated mandrel  28  in the grasping position. 
     The preform  12  is then supported by the clamp  42 , and it is joined rotationwise to the drive wheel  32 . 
     The clamp  42  is then returned to its top grasping position by the return spring  50 . The return of the clamp  42  to its top grasping position is guided progressively by the rolling of the roller  46  under the downstream slope  54  of the grasping rail  48 . Thus, the grasping operation extends over the angular segment “P 3 -P 1 ” of angle “a” all along the path of the preform  12  and the path of the mandrel  28  are superimposed, the preform  12  thus being maintained strictly vertically in line with the mandrel  28  by the clamp  42 . 
     In the grasping operation, the clamp  42  progressively raises the preform  12  to the mandrel  28  from its bottom position at the first point of intersection “P 3 ” until the mandrel  28  is fitted in the neck  20  of the preform  12  when the preform  12  reaches the input point “P 1 ” of the path of the mandrel  28 . 
     When the path of the mandrel  28  and the path of the clamp  42  diverge, the preform  12  is automatically released from the clamp  42 , the divergent movement of the preform  12  forcing the separation of the neck  20  from the clamp  42 . 
     Then, the preform  12  is transported along its path to its output point “P 2 ” which is positioned at the upstream and of the curved portion  14 A of the transport chain  14 . At this point, the preform  12  is caught by a clamp  42  in the top grasping position. 
     In planar projection, the clamp  42  has a path “P 2 -P 4 ” which is common and tangential to the path of the mandrel  28  so that the clamp  42  is in line with the mandrel  28  at least from the output point “P 2 ” at which the preform  12  is caught by the clamp  42 , to the second point of intersection “P 4 ” at which the preform  12  is transferred to the output transfer wheel  60 . 
     Then, the clamp  42  is driven to its bottom position by a releasing rail (not represented) similar to the grasping rail  48 . The clamp  42  bears on the collar  22  so as to separate the mandrel  28  from the neck  20  of the preform  12 . The preform  12  is thus released from the grip of the mandrel  28 . 
     The preform  12  is lowered to a transfer position in which the collar  22  of the preform  12  is positioned at the same height as the notches  40  of the output transfer wheel  60 . 
     The preform  12  arrives in the transfer position at the second point of intersection “P 4 ” in synchronism with a notch  40  of the output transfer wheel  60  so that the preform  12  is transferred to the notch  40  of the transfer wheel  60 . 
     To this end, the preform  12  is released from the clamp  42  at the second point of intersection “P 4 ” by means of the second arm or of an automatic control system.