Abstract:
A low speed container packaging machine is provided using a plastic carrier to hold containers and comprising a conveyor moving containers in double rows introducing them to the carrier applying section, receiving and moving them, a pair of cogwheels to locate them in synchronous position below the jaw plates, and thus apply the carrier to the containers. The jaws are mounted on the plates spinning on two axes at preset angles with respect to the horizontal and vertical planes and located symmetrically with respect to the longitudinal axis of the machine. The plates, upon spinning take the carrier strip or fastener from the feed trough and with their jaws, stretch the carrier for a 180° run and locate it on the containers and together with a suitably positioned release plate, deposit the carrier on the containers. Once the carrier is applied on the containers, the containers enter the cut station in which packages of 2, 4, 6, 8 or more containers are formed by means of a novel cutting system.

Description:
FIELD OF THE INVENTION 
     The present invention refers to container packaging machines and more particularly to low speed container packaging machines which apply plastic wrapping to containers, making packages easily carried. 
     BACKGROUND OF THE INVENTION 
     Plastic wrappings or holders are widely known and used due to their low cost. These wrappings can be applied by hand on sundry containers (cans, tins, containers, or the like.,) for a great number of products and materials but due to the high cost of production in the bottling industries for soft drinks, beers, drinking waters, or the like., it is not economically feasible to apply the wrappings by hand and therefore a package forming machine is required for the marketing of such products. 
     In the state of the art there are some container wrapping machines operating at high speed (at least 900 containers/minute), but it should be noted that currently in the market no low speed machine (500 containers/minute or less) having the features of the present invention. The following briefly describes operation of machines which work in a similar way to that described in the present invention. 
     The machine subject matter of U.S. Pat. No. 3,032,944 applies the wrapping by means of a rotary drum on which there are located a series of sliding jaws running on tracks. Their movement is controlled by means of a pair of cams, one each located on each side of the drum, and when the drum spins, the jaws slide, opening the carrier to be located on the cans. 
     U.S. Pat. No. 4,250,682 describes a machine also consisting of a rotary drum with jaws, although differing from the above in that the jaws only on one side slide while the opposite side jaws remain stationary. As in the prior machine the jaws open while the drum spins, thus opening the carrier to locate it on the tin. 
     In U.S. Pat. No. 3,383,823 is there described another machine for applying a carrier wherein a series of pins catch the carrier, and are separated to open it and locate it on the tins. 
     One further machine is described in U.S. Pat. No. 4,817,361 consist of two plates with double jaws provided in the periphery for taking the carrier band from a tray and by spinning the plates the carrier opens as said plates spin on an axis offset a certain angle with reference to the horizontal plane of the machine. In contrast to the present invention, this machine merely presents an incline, in the vertical plane, of the movement axis of the plates, while in the present invention there is an incline in the vertical plane, and one in the horizontal plane, which prevents the jaws from striking the containers during operation. 
     These machines have the disadvantages of being noisy, high production costs, relatively large sizes, complex maintenance and construction, very high operation speeds for some applications, difficult mechanical adjustments for different packages, as well as more working time for different size and diameter dimensions of the containers. The present invention describes a machine that judged by the inventors avoids these and other drawbacks. 
     OBJECTS OF THE INVENTION 
     Thus it is a primary object of the present invention to provide a low speed simple machine to package with plastic carriers different types of containers such as cans, tins and bottles of several capacities and types of materials forming thus totally automated packages of 2, 4, 6, 8 or more containers. 
     The containers subject to packaging by this machine include, but are not limited to soft drinks, beer cans, bottles, juices and preserves. Further, the materials of these containers can include without limitation, aluminum, plastic or steel. 
     Another object is to provide a low speed packaging machine having a simpler and more economic operation and maintenance. 
     Another object of the present invention is to provide a machine attending the current need for a low production speed machine (typically 450 containers/minute) with a low cost of manufacture and maintenance. 
     An additional object of the present invention is to provide a low speed packaging machine having a relatively simple and silent transmission system as compared to those machines of the state of the art currently existing. 
     Still another object of the present invention is to provide a transmission system which is safe, secure and with a low noise index. 
     Yet another object of the present invention is to provide a machine with a totally automated and flexible system for cutting the plastic carrier, and which can be programmed to act upon a certain amount of containers per package without substantial production interruption. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention comprises a plastic carrier packaging machine ( 3 ) for a plurality of containers located sideways to form packages of 2, 4, 6, 8 or more containers, which totally and continuously automated. The machine comprises a reel carrier, a feed trough, two plates with jaws, a motor driven conveyor, a removable device, a transmission system, a cutting system and an electric and electronic control device. 
     The motor driven conveyor carries the aligned containers, two by two, one exactly in front of the other, up to two non-metallic, preferably nylon, star wheels, spinning synchronized with the jaws. For this operation two non-metallic, preferably nylon, guides are used, which will release the pressure on the container line and guide said containers toward said star wheels whereby the containers are located at the exact position to receive the carrier band. 
     The plates are two solid circular pieces in which the jaws are mounted, taking and stretching transversely the carrier as the plates spin. The jaws are held by means of two screws to the plate peripheries and are located equally spaced therein. Each plate is mounted on a shaft and the longitudinal axes, are non-collinear and forming between them an angle α in the vertical plane from 155° to 175°, preferably 165° and an angle β between the same shafts in the horizontal plane from 160° to 180°, preferably 171°. The magnitude of the above referred angles may vary depending mainly on the amount it is desired to open the carrier and the dimensions of the containers, that is, height and diameter, however these angles will always be less than or equal to 180°. As can be seen from the description of the state of the art machines, this double incline in the plates is not provided in any of them. The angle of the plate driving shafts with respect to each other in the vertical plane, enables the plates through the jaws, to open the plastic carrier enough to set this carrier on the containers, while the angle between these shafts in the horizontal plane prevents the containers from colliding with the jaws when moving to the plastic carrier applying position. This angle combination allows the jaws plates upon spinning, to transversely open the carrier to reach the necessary size and thereafter start the closure to be correctly located on the containers passing below these plates on the conveyor and held by the cogwheels or stars. 
     It was found that the use of this second angle in combination with the transportation and arrangement system of the containers to the carrier application zone, that is to say the plates and nylon stars wheels, provides great advantages especially for preventing abuse or even explosion of the containers as consequence of the pressure in the contain line before and in the carrier application zone. This pressure is originated due to the required production speed, typically 450 containers per minute. It is estimated that a production less than 100 containers per minute would not require this type of system; however, due to the fact that the minimal production rate is greater, this combination is necessary. The second angle avoids engagement of the jaws with the containers as well as with the non-metallic material rails. Said otherwise, this second angle prevent engagement of the jaws of the disks with the containers and the non-metallic material guides as consequence of using this system to release the pressure in the container line. 
     Another use for the second angle is to prevent the carrier from being disengaged from the jaws before be applied. It was found that without this second angle the carrier would fall before it is applied and that a greater opening in the jaws permanently deforms the carrier. In effect, it was found surprisingly that without this second angle, the carrier, in spite of being held by the jaws from the zone in which it is taken by the disks, fell on the containers before it is applied. 
     Between both plates and located at the contact level between the carrier and the containers, there is located a separating plate which impedes climbing of the carrier with the jaws forcing their dislodgement. The containers with the carrier or fastener already located are carried by the conveyor to the cutting station. In this station there is located another non-metallic cogwheel, controlled by a manually adjustable brake, although an electromagnetic brake or any other type of automatic brake known to those skilled in the art can be used. This cogwheel limits the movement of the containers to ease the cutting step and to allow the optoelectronic detector to sense the number of containers passed in front of it. The optoelectronic detector can be substituted by an electromechanical switch or similar device. 
     As already mentioned before, the cutting system counts with an optoelectronic detector mounted on the auxiliary frame of the removable device and its function is to detect the passage and number of containers passing in front of it and to deliver a signal to activate a pneumatic electrovalve actuating a three piece nylon plunger which when descending centers and separates the containers and two knives cut the carrier separating the packages in 2, 4, 6, 8 or more containers according to the electronic selector programming. The whole plunger assembly, that is the pneumatic plunger, nylon centering means and blades or knives, is mounted on a spring hinge, allowing momentary movement together with the containers and returning to the start position once the cut is effected. This hinge is mounted over the auxiliary frame. The plunger is pneumatic although as is evident to an expert in the field another type of plunger or similar device can be employed. 
     The machine has a removable device which contains a carrier applying system and a part of the transmission system wholly mounted on a main frame. The main frame device of the removable device has been made in a way to obtain the angles α and β by the relative position between the support bearings of the driving shafts of the jaws plates. For the first angle, it is obtained by the height difference in the bearing supports of the jaw plate driving shafts and for the second angle, by a shift in the horizontal plane of the central bearings towards the entrance of the containers relative to the external bearings. 
     The transmission system comprises a main system and two secondary systems. The main system receives movement from the driving system by means of a chain and transmits this movement to the secondary systems by means of helical bevel gears. The shafts seat on the bearings and the type thereof varies depending on the required assembly. 
     The secondary transmission systems are identical as to the position of the elements thereof but are located on opposite sides of the machine as can be appreciated in the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, features, and attendant advantages of the present invention will be more fully appreciated from the following detailed description when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts throughout the several views, and wherein: 
     FIG. 1 is a perspective view of the packaging machine and shows the reel and the carrier in working position. 
     FIG. 2 is a perspective view of the container feeding zone to the machine, the movement of the containers is from right to left, as indicated by the arrow. 
     FIG. 3 is a front view of the reel carrier and its brake. 
     FIG. 4 is a side elevation view showing schematically the path of the plastic carrier in the machine from the reel to the plates. 
     FIG. 5 is a perspective view showing in detail the entrance of the plastic carrier to the feed trough. 
     FIG. 5A is an elevation view which shows the feed trough and entrance for the jaws. 
     FIG. 6 is a perspective view showing how the jaws hold and start the opening of the carrier or fastener. 
     FIG. 7 is a top plan view showing the incline angle between the driving shafts of the jaw plates. 
     FIG. 8 is a front elevational view of the entrance of the containers and in which is shown an incline angle between the driving shafts of the jaw plates. 
     FIG. 8A is a top plan view of the removable device and the parts holding it. 
     FIG. 9 is a front perspective view of the jaw plates showing the helical bevel gears and shaft supports. 
     FIG. 10 is a perspective view in which are shown in detail the release central plate, the stars, the jaw plates and part of a secondary transmission. 
     FIG. 11 is perspective view showing in detail the zone for applying the plastic carrier on the container. 
     FIG. 12 is a perspective view in which are shown the stars and the exit of the containers from the applying zone. 
     FIG. 13 is a perspective view of the main transmission, one of the secondary transmissions and the driving system; 
     FIG. 14 is a side elevation view of the secondary transmission; 
     FIG. 15 is a partial perspective view showing the cutting system and a roller carrier; 
     FIG. 16 is a perspective view of the one piece jaw used in the plates of the present invention; and 
     FIG. 17 is a partial perspective view showing the plunger assembly in the cutting position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows the machine totally assembled, and FIGS. 5A and 6 show additional detail parts thereof, wherein there is shown the location of the reel  8 , for the plastic carrier  9 , and the path thereof through the carrier rollers  10 . A feed trough  13 , in addition to guiding the carrier  9 , prefolds the side ends of the plastic carrier  9  to prevent it from being bent inwardly and to be inappropriately captured by the jaws  15  of the plates  11 , that is, starts the folding of the carrier ends, which is not done in any of the prior art machines, and once the carrier  9  is folded, it is located in the plates  11 , with jaws  15 . These one piece jaws  15 , as can be seen in FIG. 16, are not made of two or more pieces as those in the prior art, and have two threaded holes to hold the plates  11  by means of screws and two guiding holes to easily and rapidly locate them in position. 
     As can be seen from FIG. 16, the front face is concave and the back upper face is convex so that the carriers  9  take the container shape and become open without breaking. This back upper face is where the carrier  9  will be received. The lower back face of the jaw  15  is flat to adapt it to the side face of the plates  11 . 
     In FIG. 2 there is seen the conveyor  35 , running from an entrance for the containers  42  to an exit thereof for the containers  42  when they are already packaged. This conveyor  35  is comprised of plastic tablets  5 , as is well known in the art, although it can be built from another type and material. Further, the conveyor  35  includes a stainless steel frame on which plastic guides  4  are mounted, allowing side shift of the containers  42 . FIG. 2 shows the entrance zone of the conveyor  35 , with the container separating plate  3 , dividing the containers into two rows to align them and thus allow their proper entrance to the carrier applying zone. On this plate  3  are mounted two reflectors  2 , one on each face of this separating plate  3  on which infrared rays impinge from detectors  1 , to sense the presence or absence of the containers  42 , on the conveyor  35 . 
     At the end of the separating plate  3 , and already in the carrier applying zone, are located two non-metallic material plates,  17  preferably nylon, see FIGS. 7,  8   a  and  9 , opening the two rows of containers  42 , to strike tangentially the nylon stars  12 , and with this reducing the excessive pressure between the containers  42  in the conveyor  35 . The stars  12  upon spinning, synchronize the longitudinal movement of the containers  42  with the circular movement of the plates  11 , and jaws  15 , to thus apply the carrier  9 , exactly on the containers  42 . 
     In the upper part of the machine is located a device shown in FIG. 3, wherein the reel movement of carrier  6 , can be seen with its brake  7 , which controls the reel  8 , avoiding rough movements or spin inertia, further giving the required tension to the carrier  9 , for its correct application to the feed trough  13 . This brake  7 , is a manually adjustable brake which comprises a support and a brake shoe in contact with the reel carrier rotation shaft  6 . 
     In FIG. 4, the path of the carrier  9  is shown. Once withdrawn from the reel  8  and conveyed over carrier rollers  10 , the carrier  9  is thereafter introduced to the feed trough  13 , which has a double role, in the first place and due to its two piece design and having upwardly bent side ends, allows the carrier  9  to pass therebetween, folding the edges of the carrier  9  at the exit of the feed trough  13  and in the second place lays the carrier  9  in a pair of jaws  15 , and at this point stats the entrance to the stainless steel feed trough  13  grooves, as is more clearly appreciated in FIGS.  5   a  and  6 . It should be noted that all the metallic elements are stainless steel as so stated by the sanitary requirements, however it is possible to use another type of metal or material suitably performing the corresponding function. Once the carrier  9  is located, on the jaws  15 , the carrier  9  opens, see FIG. 6, as the plates  11 , spin clockwise, as seen from the driving system side, that is with the entrance of the carrier  9 , on the left side of the plates  11 , this opening of the carrier  9  is attained by spinning the plates  11 , with jaws  15  and by means of the shafts  16 , angularly shifted with preset angles on the horizontal and vertical planes. The first angle α, FIG. 8, is between the shafts  16 , with reference to the vertical plane and is for obtaining the opening of the carrier  9 . 
     Making an analogy to the handles of a clock with the movement of the plates  11 , as seen from the opposite side of the main transmission system, at the 1:00 hs. position, the jaws  15 , take the carrier  9  and when the jaws  15  reach the 7:00 hs. position, spinning counterclockwise, the maximum possible opening of the carrier  9 , is reached. The carrier  9  between the 7:00 and 6:00 hs. positions, closes due to the angles α and β, FIGS. 7 and 8, between the shafts  16  and such also helps to avoid contact between the containers  42  and the jaws  15 . When the plate  11 , with the jaws  15 , in its path passes from the 7:00 hs. to the 6:00 hs. positions, the carrier  9  contacts the central release plate  19  and this by its design and location, forces the carrier  9 , to be lowered until being free of the jaws  15 , holds the containers. The central release plate  19  is located between the two rows of container  42  and between the plates  11 , with jaws  15  and the stars  12  as seen in FIGS. 10 and 11 and made from stainless steel. 
     Once the plastic carrier  9  is applied to the containers  42 , the containers should maintain their movement on the conveyor  35  and be received by the star  31 , of the cutting station, FIG. 15, having a brake  32  coupled, thereto for reducing the container speed with reference to the tablets  5 , and for stopping the containers so as to permit a plunger with the knives and dividers  36  and the carrier  9  is cut, FIGS. 15 and 17, so that further the infrared ray detector  34  may accurately sense the passage of the containers  42  and sends a signal to an electronic counting system, which in turn generates an electric signal activating a pneumatic electrovalve  41 , which in turn activates the pneumatic plunger  33 , having coupled in its stem a mechanism with three nylon centering devices and two blades, FIG.  15 . These centering devices are used to accommodate the containers  42 , before both blades start the cut of the carrier  9 . This cutting device is mounted on an auxiliary frame  48  and is height adjustable by means of eyelets  49  and  50  as seen in FIGS. 1 and 15. On this same auxiliary frame  48  are mounted the optoelectronic detector  34  and the hinge and plunger  33  as well as the cutting assembly  36 . 
     The signal produced by the sensor  34  is sent to the electric and electronic control system, in which with a simple switch movement is selected the number of containers in the package, and this system generates an electric signal to the pneumatic electrovalve  41 , which in turn activates the pneumatic plunger  33  to cut the carrier  9  and thus obtain 2, 4, 6, 8 or more containers per package as was previously selected. 
     When the number of containers per package is required to be changed, this system does not need to carry any mechanical adjustments as the prior art machines require wherein the prior art machines also do not count even with an electronic cut selection system, nor have a cut station of the electropneumatic type as herein described. 
     The driving system comprises an electric motor  26  and a reducer  25 , both with the necessary power to move all the machine mechanisms as seen in FIG.  13 . From this reducer  25  comes out a shaft on which two sprocket wheels are located. One of these sprocket wheels by means of a chain, moves the driving axis of the conveyor  35 , located at the exit end of the container packages. 
     The other sprocket wheel  28  and through another chain  27 , rotates the sprocket wheel  28  and this in turn rotates the shaft  29 , of the main transmission, this shaft  29 , passes below the conveyor  35  towards the opposite ends to transmit the movement to the secondary transmission system. Bear in mind that both secondary systems are identical. As can be seen in FIGS. 1 and 14, the shaft  29  is held by two floor self aligning bearings fastened to the conveyor frame  35 . On the shaft  29  are mounted two helical bevel gears  21 , one on each end of the shaft  29  and at each side of the conveyor  35 , these gears  21  are coupled to respective helical bevel gears  21 , mounted on vertical shafts  20 , one at each side of the conveyor  35 . In FIGS. 13 and 14, all the above is seen in a single side of the conveyor. Such secondary transmission is symmetrical to the other side of the conveyor. Said helical bevel gears  21 , are coupled in pairs each pair forming a straight 90° angle, that is, each gear  21  is disposed at 45°. As can be seen in FIGS. 13 and 14, each shaft  20 , is held at the lower part by a floor bearing  30 , and at the upper part by a wall bearing  24 , fixed to the main frame of the removable device  44 , FIG.  8 A. In the middle part of each shaft  20 , that is at the height of the containers is mounted a pair of non-metallic preferably nylon material stars  12 , each pair of stars  12  being fastened by means of three screws with dividers  22  equally spaced and keeping the pair of stars  12 , totally parallel between them, as seen in FIG.  12 . These stars  12  are holding and synchronizing the container movements with respect to the plates  11 , with jaws  15 , to accurately locate them at the required position for placing on top of them the carrier  9 . 
     Each star  12 , comprises semi-circular grooves allowing to match the peripheral profile of one against the other, see FIG. 12, as well as to synchronize the stars  12  position, with the jaws  15 , in the plates  11 . At the upper ends of the shafts  20 , are located two helical bevel gears  14 , with the angle allowing their coupling with the gears  14  of the driving shafts  16 , which move the plates  11 , with jaws  15 . The two shafts  16 , are mounted on two floor self-aligning bearings  18  and  18 A, joined to the main frame of the removable device  44 . To mechanically couple the driving shafts  16 , to the plates  11 , with jaws  15 , a bridle  43  is used for each plate  11 . The bridles  43 , are mechanically coupled to the driving shafts  16  of the plates  11 , with jaws  15 , by means of a wedge and a stud bolt which prevents the vertical movement on the shafts  16 , the bridles  43  in turn hold the plates  11  by means of three screws, passing through three concentric semicircular grooves in said bridles which allow a circular adjustment of the plates  11 , as shown in FIG.  6 . It must be pointed out that the plates  11  are mounted and held to the bridles  43 . The plates  11  have grooves to reduce the weight thereof as shown in FIG.  1 . 
     As can be appreciated from the above description and from FIGS. 1 to  14 , the transmission movement between the shafts is carried out by means of helical bevel gears instead of the traditional chain-sprocket wheels system used in the machines of the state of the art. This provides a great simplicity to the system, at the same time reducing manufacturing costs, size of the machine, weight thereof and noise during operation. 
     The frame  39  of the removable device  44  holds the carrier  9  applying equipment, that is the support  37 , of the support bearings  10 , the support  38  of the feed trough  13 , the floor bearings  18  and  18 A, of the shafts  16 , the plates  11 , with jaws  15 , the wall bearings  24 , of the shafts  20 , the helical bevel gears  14 , and also the central release plate  19 . This frame  39  is mounted on four poles  23  one of which is shown in FIG. 12, and held by four screws with a nut  40 , which allows height adjustment as required by the size of the containers. Given the frame design  39 , and its mounting on the poles  23 , it is very simple if necessary to withdraw the same from the machine and substitute it by another previously set to the required container size. This implies that the screws with nuts  40  have a double role of holding the frame  39  of the removable device  44  and to adjust its height with reference to the containers  42 . As will be seen further ahead, there is a need to modify this height when changing the height of the containers  42  to be packaged. 
     The frame  39  of the removable device  44  is built with conventional stainless steel structural elements welded to each other, although another type of material with similar mechanical resistance and corrosion resistance features can be used. As was previously mentioned, the angle α is obtained by placing in the horizontal plane at different levels, the support structural elements for the bearings; the central structural element  46  of the removable device  44  in the longitudinal center of the machine for the bearings  18 A is disposed at a certain level and the external structural element  47  of the removable device  44  is disposed at an upper level for the bearings  18  holding between them, the driving shafts  16 , and the helical bevel gears  14 , of the plates  11 , with jaws  15 , as can be seen from FIG.  8 A. With reference to the second angle β from FIGS.  7  and  8   a  it can be noted that this angle is obtained by making the bearing axes  18  and  18 A non-collinear in the horizontal plane. The lower structural element  45  holds the wall bearings  24  and the support  38  of the feed trough  13 , the medium level structural element  46  holds the central bearings  18 A and the central release plate  19 , the upper level structural element  47  holds the external bearings  18  and the roller carriers support  10  and furthermore by one end holds the auxiliary frame  48  of the cutting system by means of three screws and eyelets  49 . 
     The removable device  44  as can be seen from the above description, comprises the metallic frame  39  built with the structural elements as was previously mentioned, the support  37 , the carrier rollers  10 , the support  38 , the feed trough  13 , the floor bearings  18 , the shafts  16 , the plates  11 , with jaws  15 , the wall bearings  24 , the shafts  20  and also the central release plate  19 . 
     When the need occurs the need to modify the machine by changes in the size of the containers and at any when it is required to use the machine with another type of container with different measurements, the following procedures are to be carried out, depending on the type of container: 
     a) With the diameter size change on the container cap and same body diameter: 
     Adjustment of the distance between the plates  11  without varying the angles. 
     The feed trough  13  is changed, suitable for the new plastic carrier  9 . 
     b) If the height of the containers is changed and the cap and diameters of the body of the container  42  are kept: 
     The frame  39  is leveled, with the screws with nuts  40 , on the poles  23 . 
     The cutting station is leveled (auxiliary frame). 
     c) If the change is in the diameters of the body and the cap of the container  42 : 
     The removable device  44  is replaced. 
     The stars  12  are changed. 
     Blades and dividers  36  are substituted. 
     d) If the change is in the height and the diameters of the container  42 : 
     Procedure c) is carried out. 
     Next, procedure b) is carried out. 
     Any of these change or conversion procedures do not exceed 90 minutes in working time, that is, it is very easy and fast to carry out, as well as more economical in cost, differing from the machines of the already described patents which require from one to three work days to carry out some modification in the format and conversion due to a change in dimensions of the container, and also a difference in cost considering the total cost of the machine provided in this patent application. 
     To control the machine movements, sequence and synchronization of the function detectors with these movements, there is used an electric and electronic control system mounted in a panel in which are also located light indicators and buttons. This control panel (not shown) generates the electrical signals of the motor  26 , of the electrovalve  41 , of the light indicators (not shown) and receives the signals of the on, start stop and speed buttons of the machine as well as the signals of the detectors  1 , of the security reflectors  2 , that of the doors (not shown) and of the optoelectronic detector  34 , which detects the number of containers  42 , and sends the signal to the control panel so it actuates the electrovalve  41  of the cutting system. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.