CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related with Application Ser. No. 09/294,186, filed on Apr. 19, 1999 and entitled “AN AUTOMATIC BAGGING MACHINE”, assigned to the assignee of the present application. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an automatic turret bagging machine wherein the trap walls of the compartments are controlled by a control plate and wherein an insufficient number of pouches loaded in the compartments of the turret transport mechanism will be detected and unloaded for recycling. 
     BACKGROUND ART 
     Various types of automatic bagging machines are known for placing all sorts of articles into an open top end of a bag held under an article transport and discharge mechanism. It is also known to transport articles in compartments of a turret and to load them at a loading station and to discharge them at a discharge station. 
     The present invention is concerned with these types of automatic bagging machines utilizing turret transport mechanisms. However, a problem which exists with these transport mechanism is that often an improper number of articles are placed into the compartments of the turret transport mechanism and these improper number of articles are then discharged into a bag. This causes other problems when handling the bag down line. It is therefore necessary to inspect the bags which are conveyed from the bagging machine to detect improperly filled bags. This is costly and time-consuming and still bags with an improper number of articles therein go undetected and are sold in that state causing further problems at the retail and consumer level. Another problem with these machines is that they are slow in operation and often the bagging machine must be stopped to correct malfunctions and/or improper loading of compartments. 
     SUMMARY OF INVENTION 
     It is therefore a feature of the present invention to provide an automatic turret bagging machine which substantially overcomes the above-mentioned disadvantages of the prior art. 
     Another feature of the present invention is to provide an automatic turret bagging machine which is indexed in synchronism with a displaceable control plate whereby to cause a trap door at the base of the turret compartments to open to discharge the articles placed therein and to automatically close. 
     Another feature of the present invention is to provide a detection system in combination with the automatic turret bagging machine and wherein the detection system will signal a control circuit to, in turn, control the operation of the control plate in order to discharge an improper number of articles placed into a compartment at a discharge position where these articles can be accumulated and recycled without spoilage. 
     Another feature of the present invention is to provide an automatic turret bagging machine which can operate at high speed and which can load three milk pouches oriented in side-by-side longitudinal relationship within a carrying bag. 
     According to the above features, from a broad aspect, the present invention provides an automatic turret bagging machine which comprises a turret transport mechanism having four article receiving compartments. Drive means is provided to displace the compartments in synchronism from an article loading position, an article discharge position, an intermediate position and an article unloading position. Each of the compartments has a circumferential side wall, an open top end and a bottom trap wall. The compartments are dimensioned to receive two or more liquid pouches oriented in a predetermined manner by loading means at the loading position. A bag opening and holding mechanism is provided for positioning and holding an open top end of a bag under the bottom trap wall of the compartments at the article discharge position. Controllable release means is provided to release the bottom trap wall of the compartments upon reaching the article discharge position to release the pouches contained in the compartment into the open top end of a bag positioned thereunder. Transport means is provided to displace the bag with the pouches therein away from the bag opening and holding mechanism. Control means is provided to synchronize the operation of the drive means, the bag opening and holding mechanism, the loading means and the controllable release means. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
     FIG. 1 is a side view of the automatic turret bagging machine of the present invention as utilized with a pouch loading conveyor, a bag opening and holding mechanism and a bag closing assembly of the prior art; 
     FIG. 2 is a top view of FIG. 1; 
     FIG. 3 is a schematic top view of the turret transport mechanism and its compartments; 
     FIG. 4 is a bottom view illustrating the position of the control plate and its association with the turret transport mechanism and the follower bearing member connected to the bottom trap wall of each of the compartments of the turret transport mechanism; 
     FIG. 5 is a bottom plan view showing the actual construction of the control plate for repositioning the bottom trap wall of the compartments to a closed position; 
     FIG. 6 is a simplified sectional side view showing a transport compartment of the turret transport mechanism approaching the unloading position with a bag being opened thereat and under the bottom trap wall of the compartment; 
     FIG. 7 is a view similar to FIG. 6 but illustrating the discharge of the pouches within the transport compartment at the discharge position and into an open end of a bag held under the trap wall of the compartment; 
     FIG. 8 is a simplified fragmented sectional view illustrating the construction of the pouch detection system for detecting proper and improper number of pouches being released into the compartment of the turret transport mechanism at the loading position; 
     FIG. 9 is a view similar to FIG. 8 but illustrating an improper quantity of pouches being discharged at the loading position; and 
     FIG. 10 is a simplified block diagram of the control circuit system. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings and more particularly to FIGS. 1 to  3 , there is shown at  10  the automatic turret bagging machine of the present invention. The turret bagging machine is a turret transport mechanism  10 ′ provided with four article receiving compartments  11  disposed in spaced parallel relationship to each side of a square support frame  12  as shown in FIG.  3 . The turret transport mechanism  10 ′ is supported above and adjacent to a bag opening and holding mechanism  13  as is well known in the art and for example as described in U.S. Pat. No. 5,177,939, dated Jan. 12, 1993. The bagging mechanism  13  engages an outer plastic bag  14 ′ from a plurality of wicketted bags (see FIGS. 6 and 7) and opens the mouth  14 ″ thereof at the article discharge station  15  above the compartments  11 . 
     At the article discharge position  15 , articles, herein milk pouches  16  transported in the compartment  11 , are released into the open end of the plastic bag  14 ′ (see FIG. 6) held thereunder. The filled bag  14 ′ with a predetermined number of pouches, herein three pouches positioned therein, is conveyed on a transport conveyor to a bag open end film gathering station  17  (well known in the art) wherein gathering brushes will gather the open end of the bag  14 ′ to feed the gathered end into a closure application station  18  where a closure element is positioned about the gathered throat portion  19  of the bag  14 ′. The bag with the pouches therein is transported on a transport conveyor  20  which displaces the bag with the pouches through the stations  17  and  18  and then discharges the bag onto another conveyor, not shown. 
     As shown in FIGS. 1 and 2, a feed belt conveyor  21  is provided with spaced-apart pusher plates  22  and fed groups of three milk pouches  16  at a loading end  23  of the conveyor being fed by twin tube fillers  24  also well known in the art. These fillers  24  form the pouches, as illustrated at  16 ′, fill them and seal them and then release the pouches on the loading end  23  of the conveyor at predetermined positions to grasp the pouches. The pouches then travel onto a steep inclined transfer conveyor section  25  to cause the groups  16 ″, see FIG. 2, of three pouches  16  to position themselves by gravity against the pusher plates  22  in side-by-side relationship with the pouches oriented longitudinally. The pouches then move on to a discharge end  26  of a conveyor  25  where they are released into the open top end  27  of the compartment  11  at the loading station  28 . The conveyor  21  is synchronized with the turret transport mechanism  10 ′. 
     Referring now to FIGS. 3 to  5 , there will be described the operation of the turret transport mechanism  10 ′ of the present invention and its control plate  29  disposed thereunder. As shown in FIG. 3, the square support frame  12  of the turret transport mechanism  10 ′ has a compartment  11  secured to each of the opposed parallel side frame  30  thereof and the support frame  12  is rotated by an indexing motor  31  which displaces the compartments  11  in a clockwise direction and at positions of 90° with respect to one another. Each compartment has a circumferential side wall and as herein shown of a rectangular cross-section defining opposed end walls  32 , opposed side walls  33 , a bottom trap wall  34  and an open rectangular top end  27 , as previously described. The milk pouches  16  are loaded into the compartment at the loading position  28  with the milk pouches being received in close fit within the compartments  11 , as illustrated in FIG.  3 . 
     The motor  31  is then operated to move the compartment from the loading position  28  to the discharge position  15  where the bottom trap wall  34  is released to discharge the articles within the open top end of the bag  14 ′ supported thereunder (see FIGS.  6  and  7 ). The bag  14 ′ is then released and conveyed free of the trap wall  34 . The trap wall  34  remains open as the support frame  12  moves the compartment to an intermediate position  35  unless the compartment carries an improper number of pouches which have been detected and which have not been released at the discharge position  15 , as will be described later. During the next indexing cycle of the motor  31 , the compartment is moved to a bag discharge position  36 . If there are an improper number of pouches within the compartment, they are discharged at this position by the control plate  29 , as will be described later. If the trap wall  34  is open, then it remains in that open position. 
     As shown in FIGS. 4 and 5, as the indexing motor  31  rotates the support frame  12  from the discharge position  36  to the loading position  28 , the leading edge  37  of the bottom trap wall  34 , which is depending, will abut against an edge formation  38  of the control plate  29  to cause the trap wall  34  to hinge upwardly under the open bottom end of the compartment and with its bearing element engaged under the control plate whereby to close the compartment. 
     The control plate  29  constitutes a controllable release means and the plate is displaceably supported in a plane disposed relative to the bottom trap wall of the compartments. The bottom trap walls of the compartments are also provided with biased follower means secured thereto and herein constituted by a rod  39  having a follower bearing or roller element  40  secured adjacent a free end thereof. The roller element  40  is disposed under the bottom surface of the control plate  29 , as shown in FIG. 4, and rides along a peripheral edge portion  42  of this surface. This is better illustrated in FIG.  6  and as can be seen, the bottom trap wall  34  and the connecting rod  39  secured thereto are displaceable on a pivot connection  43 . A spring  44  may be connected to the connecting rod  39  to urge it upwardly to a trap wall release position, as shown in FIG.  7 . 
     The control plate  29  is displaceable in its plane by a piston rod connection  46 ′ secured to a piston rod  45  of a piston cylinder  46 . This piston cylinder is controlled by a control circuit  47 , as shown in FIG.  10 . The indexing motor  31  is also controlled by the control circuit  47 . The control circuit  47  also controls all of the conveyor drives of the system. 
     As shown in FIGS. 4 and 5, the control plate  29 , or plate assembly  29 ′ is configured so that the roller element  40  travels substantially along the peripheral flat portion  42 ,  42 ′ of its lower arresting bottom surface  41 ,  41 ′. The control plate has a front edge  48 ,  48 ′ which is disposed spaced behind the article discharge position  15  and a rear edge  49 ,  49 ′ disposed spaced a greater distance from the article unloading position  36 ,  36 ′. It also has opposed parallel side edges  50  disposed respectively adjacent the article loading position  28  and the intermediate position  35 . Upon receiving of a signal from the control circuit  47 , the piston cylinder  46 ,  46 ′ is actuated to draw the plate to its position as shown in phantom lines at  29 ′ in FIG. 4, whereby to release the roller element  40  from its engagement with the bottom surface  41  of the control plate  29  as illustrated in FIG.  7 . The control plate is withdrawn in the direction of arrow  51 , as illustrated in FIG.  7 . 
     As can be seen from FIGS. 6 and 7, the weight of the pouches  16  within the compartment  11  will cause the bottom trap wall  34  to pivot wherein the pouches  16  are released by gravity into the open top end  52  of the bag  14 ′ retained open under the compartment at the article discharge position  15 . The spring  44  ensures that the trap wall  34  is open at all times when the roller element  40  is released from the surface  41  by the displacement of the control plate. When the control plate is in its retracted position, as shown in phantom line in FIG. 4, it can be seen that the rear edge  49  of the control plate is closer to the rear side frame  30 ′ of the support frame  12  whereby to position the abutment edge formation  38  along the path of displacement of the compartments to cause the leading edge  37  of the trap wall of the compartment at the discharge location  36  to move up onto the edge formation  38  prior to reaching the loading position  28  and thereby positioning the follower roller element  40  back under the control plate and in contact with the bottom surface  41  thereof. Once the compartment reaches the loading position, it is arrested momentarily and during this short period of time the control circuit  47  actuates the control plate cylinder  46  to reposition the control plate to its position as shown in solid line in FIG.  4 . 
     With additional reference now to FIGS. 8 and 9 there will be described a detection system whereby to detect that there is a proper number of milk pouches  16  at the discharge end  26  of the feed belt conveyor  21 . As shown in FIG. 8, the feed belt conveyor  21  is provided with side guide plates  60 , which guide the three milk pouches  16  in close side-by-side longitudinally aligned relationship and holds them captive between the side plates. An infrared beam transmitter  61  emits a light beam  62  across the plates  60  and this light beam is received by a receiver  63  or detector which feeds a signal to the control circuit  47 , as illustrated in FIG. 10, when the light beam  62  is uninterrupted. As shown in FIG. 8, the light beam is interrupted by the pouches and accordingly the receiver or detector  63  will not transmit a signal to the control circuit  47 . In the event that only one or two pouches  16  are loaded on the conveyor, as shown in FIG. 9, these pouches will collapse and not obstruct the light beam  62  which will be detected by the receiver/detector  63  and a signal will be sent to the control circuit  47 . This signal will cause the control circuit to arrest the piston cylinder  46  when the compartment with the improper number of pouches reaches the article discharge position  15 . The roller element  40  will remain engaged under the surface  41  of the control plate and maintain the bottom trap wall  34  closed and accordingly, those articles will not be discharged. Simultaneously, the control circuit  47  will arrest the conveyors  20  and  21  and the bag opening and holding mechanism  13  until the indexing motor moves the compartment to the next 90° index position. This closed compartment will remain closed due to the shape of the control plate which maintains the roller element in engagement with its lower surface. However, upon reaching the article discharge position  36 , the plate rear edge  49  is spaced further from the rear side frame or edge  30 ′ of the turret support frame and this will cause the roller element  40  to become disengaged and therefore release the bottom trap wall of the compartment and the one or two pouches contained therein. A conveyor, not shown, will then convey these pouches back to a recycling position where they can be positioned again on the feed belt conveyor  21  and reloaded with a proper grouping. 
     It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein, provided such modifications fall within the scope of the appended claims.
An automatic turret bagging machine utilizes a turret transport mechanism having four article receiving compartments to receive liquid pouches, herein milk pouches, oriented longitudinally therein. An indexing motor drives the turret transport mechanism between an article loading position, an article discharge position, an intermediate position and an article unloading position. A control plate is synchronized with the turret transport mechanism and provides a support for a follower bearing member secured to the trap door of each of the compartments whereby to retain and release articles loaded in the compartments. The control plate also has a formation which automatically recloses the trap doors of the compartment upon reaching a predetermined position and simultaneously repositions the follower bearing member with a lower surface of the control plate. In the event that an improper number of pouches are loaded in a compartment, that compartment will not unload and the discharge position and the bag opening and positioning mechanism will idle during one cycle step and the improper number of pouches will automatically be discharged at the article unloading position for recycling.