MXPA00005400A - Container forming method and apparatus - Google Patents

Abstract

Disclosed is a new machine for forming strong, durable and recyclable containers of the type described in U.S. Pat. No. 5,497,939 without the use of glue or nails which are ready to be loaded, closed, stacked and shipped. The machine utilizes a mandrel movably mounted on a path between retracted and extended positions. As the mandrel cycles forward, it first receives two synthetic sidewalls of the container to be formed, which are firmly compressed against the sides of the mandrel as it moves forward. The mandrel next encounters the body panel or wrap of the container to be formed, said wrap including a plurality of tabs along the edges of its two longer sides which correspond to locking slots on the sidewalls. As the mandrel moves forward, it pushes into the middle of the wrap whereupon a set of plows and shoes bend the upper and lower portions of the wrap into a more horizontal orientation, leaving the middle of the wrap in a vertical position. As the mandrel pushes the wrap through the machine, a set of moveable upper and lower rockers containing unique pressure mechanisms press the tabs on the horizontally oriented portion of the wrap into the locking slots on the ends of the sidewalls. When the mandrel is fully extended, pressure is applied to the tabs on the vertically oriented middle section of the wrap to form the bottom of the container using a pair of hinge-mounted pressure plates fitted with unique biased brackets

Description

METHOD AND APPARATUS FOR MOLDING A CONTAINER DESCRIPTION OF THE INVENTION The present invention relates to container molding machines, and in particular to a new method and apparatus for molding containers of a type having rigid side walls and which are originally fixed to a container. Hard cardboard or plastic wrap. A wide variety of cardboard containers for shipping and storage are known in the art. An equally wide variety of container molding machines are also known in the art. Among the most common uses of such containers are packaging, shipping and storage of fresh fruits and vegetables, and for the storage and shipping of pre-packaged goods (eg soup cans, beverage bottles, jelly jars, bags of rice, cardboard boxes of cereal, etc.). Such containers are typically made of cardboard materials such as, without limitation, single-sided corrugated, corrugated one-sided (double-sided), double-wall corrugated, triple wall corrugated, carton for containers, cardboard for boxes, cardboard for coated, hard cardboard and cardboard. There are several well-known styles of containers that have been developed over the years, each optimally adapted for one or more particular products or industries.

The shipment and storage of fresh fruits such as table grapes, poses particular problems due to the delicate nature of the fruits, the cold temperatures in which the fruit is stored and the need to pack, ship and store large quantities of fruit in containers of reasonable size. Several cardboard containers have reinforced sides or end panels to improve stacking resistance, such as those described in US Patent No. 4,905,834. However, even with such reinforcements, these containers still suffer from significant limitations of stacking resistance because they are made of cardboard. The cardboard can easily get wet from causes such as rain, condensation in cold storage, breakage of fresh fruit or similar conditions, for which it loses resistance to stacking. Adding wax to such cartons can improve their resilience, although it also returns to the non-recyclable cardboard container. A known shipping container provides one or more panels of hard cardboard between two wooden end plates, these panels are nailed to the end plates. Although the use of wood improves the stacking resistance of the container, such containers tend to slip against each other, particularly in higher rows. In addition, the wooden end plates in the container can damage the fruit, the wood is expensive and disassemble the nails, and the hard cardboard of the wood panels is stubborn, making it difficult to reuse such containers or to recycle them. Replacing the wooden side panels of such containers with injection molded polypropylene can reduce the cost, but does not solve the slip problem and exacerbates the problem of recycling. In response to these problems, a new container has been developed which is the subject of the Patent North American No. 5,497,939. This new container uses two specially designated plastic side walls (terminal panels) and a panel for fixing between them. Each plastic side panel has stacking tabs at the top, corresponding to the receiving slots at the bottom and a set of locking slots at the bottom and at the side edges thereof. The attachable panel includes a series of latching tongues protruding along its sides, and each tab has at least one opening therein. The panel is placed between the two side walls in such a way that the edges of the panel are folded around the side walls, the tabs of the panel engage with the locking grooves of the side walls to form a solid stackable container. Molding such a container without the use of adhesives or nails allows the panel envelope to be easily and neatly disengaged from the side walls, thereby allowing the envelope to be recycled and the side walls to be reused. Accordingly, a method and apparatus for molding the unique containers of U.S. Patent No. 5,497,939 are needed. In particular, such containers require an apparatus that is capable of firmly holding the plastic side walls in place, attaching the wrapping panel to the side walls by crimping the tabs on the wrapping with the locking slots on the bottom and lateral edges of the side walls, and prevent the central portion of the panel envelope from buckling or unmolding, all without using adhesives or nails. Virtually all cardboard machines use adhesives to join the various pieces of the cardboard container together. Some machines fold a simple cardboard cut into a container having a particular shape, such as that shown in US Patent No. 3,858,489; and others fold and eventually join two or more pieces of cardboard to form a container, such as that shown in US Patent No. 4,238,188. U.S. Patent No. 4,637,544 discloses a container box having two synthetic side walls connected by a folded sheet of card stock. However, both side walls include U-shaped notches recessed in the faces thereof to receive the edges of the folded piece of card. A set of teeth found in the notches is used to attach the side walls to the piece of folded cardboard. Therefore, the piece of cardboard must be folded first and placed in an exact position, then each of the side walls must be inserted precisely on the ends of the folded piece so that the edges of the piece fit into the notches and Crimp with the teeth. This patent does not reveal any apparatus to carry out this task. In contrast, the panel of the container formed by the present invention interlocks with locking grooves in the outer side surfaces of the side walls, by engaging a series of panel tabs with the locking grooves in the side walls. The present invention provides a method and apparatus for making containers of the type described using a movable mandrel mounted on a path between the retracted and extended positions. The cycle for molding a container begins with the complete retraction of the mandrel. After being retracted, the mandrel moves forward to first receive the two synthetic walls of the container to be formed, one on each side. The side walls are pressed firmly against the mandrel using pressure plates one on each side. A rectangular hardboard or panel of the plastic frame or wrapping panel is placed in the trajectory of the mandrel in a vertical orientation. The wrapping panel includes a plurality of tabs' along the edges of its two longer sides. These tongues correspond to the locking grooves in the surfaces of the lower part and in the lateral edges of the side walls. Each tab has an opening therein to receive the corresponding button located in each slot of the side wall. A series of shoes and chisels are provided above and below the trajectory of the mandrel on the other side of the wrapper. As the mandrel moves forward, it pushes inward from the center of the wrapper. At the same time, the shoes and chisels flex the upper and lower portions of the envelope in a more horizontal orientation, leaving the center of the envelope in a vertical position. As the mandrel continues forward, the outer edges of the wrapper come into contact with the edges of the outer surface of the two side walls. As more fully described in the container patent "939, each of the side walls includes a plurality of locking slots or recesses with buttons thereon at their outer edges to engage with the tabs and wrapping openings of the panel. Typical mode, there are two (2) such recess and button areas at each end of each side panel and three (3) such areas at the top of the rada panel.As the sheath is pushed through the machine , a set of movable upper and lower rocker arms press the wrapping tabs of the panel into the horizontally oriented portion of the shell towards the locking grooves at the ends of the side walls with sufficient pressure not only to force the tabs to enter the grooves of locking, but also to push the tabs towards the buttons of the side walls in such a way that the buttons extend through the openings of the the tabs of the frame panels. This pressure is carried out as the parts of the container pass through the rockers. As a result, the tongues of the hopzontally (folded) oriented portions of the envelope are crimped at the upper and lower edges of the side walls. Then, when the mandrel is fully extended, pressure is applied to the tabs of the vertically oriented middle section of the casing (which will mold the upper part of the container to be molded), in order to engage the remaining cassette tabs of the cassette. panel in this section with the corresponding slots and buttons of the upper ends of the two side walls. Pressure is applied to these remaining tabs using a pair of hinged pressure plates adapted with a unique beveled clamp, wherein each plate provides pressure to the tabs on one side of the casing. The clamps push the tabs into the locking slots of the corresponding side wall with sufficient force to also push the buttons through the holes of the tabs. The side walls are then released by the mandrel, the end hinged plates are opened and the resulting container is removed from the machine. Then the mandrel is completely retracted and the machine starts another cycle. The result is another container built without the use of adhesive or nails that is very solid and ready to be loaded, closed, stacked and shipped. Other unique features of the machine include protruding shoes and chisels that provide a unique crimp of the panel envelope on both the top and the bottom of the areas of the side walls. These protruding shoes prevent the open area of the panel envelope between the side walls from being buckled or unmoulded when the tabs lock into the side walls. Also unique is a lock on each side that holds the side wall in place against the mandrel and aligns it in a secure manner as it passes between the pressure rockers. These locks prevent the side walls from sliding or sliding to re that the tabs of the panel casing align with the locking slots in the side walls and to re that the buttons on the side walls align with the openings in the walls. tabs Another unique feature is the use of cables to transmit and / or impart movement from one or more of the cams that rotate centrally outwardly of the machine's pressure plates and rocker arms. It is therefore a principal object of the present invention to provide a method and apparatus for molding containers having two side walls of plastics fixed to a central panel wrap of hard cardboard or plastic without the use of adhesives or nails. It is also an important object of the present invention to provide a method and apparatus for molding containers having two plastic side walls having a plurality of recesses and buttons at their peripheral edges which are crimped with a plurality of corresponding tabs with openings located at along the edges of a hard cardboard or plastic panel wrap.

It is another object of the present invention to provide a method and apparatus for molding containers of a type having two plastic side walls fixed to a central panel wrap that causes a plurality of tabs with apertures therein located in the wrapping that goes to be crimped with a plurality of corresponding recesses and buttons located in the side walls for a firm attachment of the panel to the side walls without the use of nails or adhesives. It is also an important object of the present invention to provide a method and an apparatus for molding containers of the type described above whose containers can be easily disassembled for recycling and / or reuse of the panel envelope and the side walls. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above including tabs and grooves in the upper and lower ends thereof, respectively, which allow stable and high stacking of such containers. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above whose containers are resistant to damage or collapse caused by moisture. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above that use protruding shoes to prevent deformation of the panel when the tabs thereon are crimped with the side walls. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above that utilize a latch to securely hold the side walls in place when pressure is applied to secure the tabs of the panel shell to the recesses and buttons of the same. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above using single cabling to impart movement from the rotating cams to various operating parts remote from the machine. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above that use unique pressure rockers to secure the tabs and openings in the panel sections oriented horizontally to the corresponding slots and buttons in the side walls. It is also an important object of the present invention to provide a method and apparatus for molding containers of the type described above that use unique pressure plates and clamps to secure the tabs and openings in the sections of the panel envelope oriented vertically to the corresponding recesses. and buttons on the side walls. Other objects of the invention will be apparent from the detailed descriptions and claims herein. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front perspective view largely simplified of the chassis of the invention. Figure 2 is a partially simplified rear perspective view of the operating mechanism of the present invention. Figure 3 is a side cross-sectional view of the invention showing the wrapping of the panel around the side walls before the locking engagement of the tabs and buttons. Figure 4 is a sectional, cross-sectional end view of the invention shown in Figure 3 with the panel envelope around the side walls. Figure 5 is an enlarged cross-sectional end view of the button of the crimping mechanism of Figure 4. Figure 6 is an isometric view partially cut away. increased showing the wiring system of the present invention. Figure 7 is an enlarged cross-sectional view of a pressure clamp. Figure 8 is an enlarged side view of a pressure beam. Figure 9 is a cross-sectional side view of the pressure beam of Figure 8 which also shows a detail of the side wall. Figure 10 is a series of isometric views of the container parts showing the molding steps of the machine of the present invention. Figure 11 is a view of the wrapping of the panel and of the side walls showing their respective positions in the machine of the invention (without the machine itself being shown) before the forward cycle of the mandrel. Figure 12 is a view of the envelope of the panel and of the side walls showing their respective positions in the machine of the invention (without showing the machine itself) at half cycle, after crimping the tabs of the wrapping of the horizontal panel with the locking grooves at the ends of the side walls. Figure 13 is a view of the envelope of the panel and of the side walls showing their respective positions in the machine of the invention (without the machine itself being shown) at the end of the cycle, after crimping the tabs of the envelope of the vertical panel with the locking slots in the lower part of the side walls. With reference to the drawings in which similar reference characters designate corresponding or similar parts throughout the various views, and with reference, particularly to Figures 1 and 2 it is seen that the invention includes a mandrel 20 which is movable between a retracted position to the front of the machine and an extended position on the back of the machine. Along the trajectory 19 of the mandrel, the following general operating steps are provided: (a) the delivery units of the side wall, generally represented by adjustable hoppers 33 and 34; (b) a panel wrapping feeding mechanism on the top, generally represented by the guides 32 and 37-40; (c) a set of shoes and chisels for molding the container, generally 22-29; (d) a set of locks of the side wall, generally 52-55; (e) a set of pressure rockers, generally 62-65; and (f) a pair of hinged terminal pressure plates, generally 82-83. As the mandrel 20 undergoes a forward cycle, the first stage encountered is the sidewall delivery units. Two pivotally fixed side wall hoppers 33 and 34 are provided, one on each side of the mandrel, mounted on an arm of adjustable length 35, 36. The stacks of the side walls 71 are laterally loaded into the hoppers 33 and 34, with the most of the side walls of the upper part in the position shown in Figure 11. In particular, the side walls 71 are oriented in the hoppers 33 and 34 in such a way that their end surfaces 72 contain the locking slots 75 and the buttons 76 are parallel to the travel path of the mandrel 20 (see direction arrow of Figure 11); the upper edges 80 of the side walls with stacking tabs 73 are oriented perpendicular to the trajectory of the mandrel, so that they face the approaching mandrel; and the lower surfaces 74 of the side walls containing locking grooves 77 and buttons 78 are oriented perpendicular to the trajectory of the mandrel, so that they face away from the mandrel moving forward.

During each cycle of the machine, two side pairs 71 are removed, one from each hopper on each side and carried forward by the mandrel. Both sides of the mandrel 20 are provided with pointed peaks 21 that pierce the surfaces of the side walls 71 to hold them in place against the mandrel while it is moving forward (see details, Figure 3). These peaks work together with the shoes, chisels and locks of the later stages to keep the side walls in a proper orientation. When the machine repeats the cycle over and over again, the additional stacks of side walls 71 must be loaded into hoppers 33 and 3. The second stage that the mandrel encounters while going in its forward cycle is the panel wrapping feeding mechanism made of a supporting channel 32, the guides 37, 38, 39 and 40, and the vacuum feeder. These guides are capable of receiving and supporting a stack of flat wrapping panels 45, each wrapping in a vertical orientation. A set of vacuum suction cups 15 is provided on an adjustable support 16 adjacent to the lower position of the guides 37-40. Suction is applied to the cups 15 and the holder 16 extends the cups outward to take the lower wrapper 45 of the stack. The movement of the support 16 places the casing 45 between the rotating wheels 17 and 18. The rotation of these wheels supplies the casing 45 to the front of the retracted mandrel 20 before it begins its next forward cycle, this position is shown in Figure 1 with the dotted lines. This is also the position shown in Figure 11. The mandrel picks up this wrap 45 and carries it forward along with the side walls 71 that it has already taken from the hoppers 33 and 34. The wrappers 45 can be made of any suitable material including without limitation plastic, hardboard, corrugated cardboard and similar materials. As shown in Figure 11, each wrap 45 includes a plurality of tabs 41 and 42 along its two longer parallel sides. Each of the tabs 41 and 42 has an opening or hole 43 therein. The end tabs 41 are positioned for crimping with the final working grooves 75 in the side walls 71. The tabs of the bottom part 42 are positioned to be crimped with the locking grooves of the bottom part 77 in the side walls 71. In particular, each locking groove 75 and 77 includes a pair of small flanges or tabs (extensions) 79 which make the outer openings of the grooves 75 and 77 slightly narrower than the inside of the grooves themselves (see detail in Figure 9) . The tabs 41 and 42 are approximately the same size as the slots 75 and 77 but are wider than the narrow openings in these slots created by the tabs 79. Accordingly, once a tab 41 or 42, respectively, are inserted by compression through the tabs 79 within the slot 75 or 77, respectively, the tabs 79"lock" the tab in place preventing it from being removed. The second stage that the mandrel finds while going in its forward cycle is the feeding mechanism The third stage that the mandrel encounters as it is subjected to a forward cycle is the area of demoulding of the wrapper that includes a delay device and release shoes. The casing then encounters a plurality of primary shoes or chisels 23, 25 and 27, 29. These are provided above and below the mandrel path to flex and unmold the upper and lower sections of the casing 45 while being pushed towards forward through the mandrel (see Figures 3-5). A set of secondary shoes or chisels 22, 24 and 26, 28 are provided immediately adjacent to and slightly protruding from the primary shoes 23, 25, 27 and 29 respectively. These secondary shoes guide the outer edges 72 of the side walls 71 (containing the slots 75 and the buttons 76) through the machine. Each of the primary and secondary shoes includes an outwardly angled section to facilitate bending of the wrapper 45 and the guide of the wrapper 45 and of the side walls 71 while the mandrel pushes them through the machine. As the mandrel moves towards the vicinity of the primary and secondary shoes 22-29, find the fourth stage made of a set of four retractable locks loaded by springs 52-55 which are activated to press the side walls 71 firmly against the sides' of the mandrel 20 (see Figures 4 and 5). The locks 52-55 are mounted in the upper and lower positions along each side of the mandrel 20. As the mandrel 20 moves forward with the side walls 71 fixed on each side using its peaks 21, the side walls rub against and slide along the locks 52-55. The tabs of the casing 42 also come into contact with these locks to be aligned. The friction between the locks and the side walls 71 holds them securely in place for the next operation of the machine. The fifth stage found by the mandrel that is subjected to a forward cycle are the pressure rockers 62-65 best shown in Figure 3. Two upper rockers 62 and 63 are provided above the trajectory of the mandrel adjacent to the shoes 23 and 25, respectively. Two lower rockers 64 and 65 are provided below the mandrel path adjacent to the shoes 27 and 29, respectively. Each rocker arm 62-65 is pivotally mounted on a rotating shaft so as to move in an arcuate path back and forth in two defined positions (ie "swing"). Details of the rocker arms and the compression locks are found in Figures 8 and 9. The description of each rocker 62-65 is the same. Each rocker arm (for example 62) includes a plurality of extensions 69 on which the resilient compression links 66 are mounted. Each extension 69 and locks 66 correspond to a locking groove 75 in the side wall 71, and a tongue 41 in the panel wrap 45. Each latch 62-65 includes an opening 60 within which a slidably mounted pressure imparting member 61 is provided. The pressure member 61 is fixed to one end of a resilient member 67, in the form of a spring or of another similar artifact, which in turn is captured inside the opening 60. The other end of the pressing member 61 defines an annular flange 70 defining an opening. The flange 70 can be extended outwardly away from the lock 66 due to the action of the resilient member 67, but its travel path is limited by a fixed pin 68. The inner opening of the annular flange 70 corresponds to the buttons 76 in the side walls 71, and the openings of the tabs 43 in the wrapping of the panel 45. As the mandrel pushes the wrapping of the demolded panel 45 and the side walls 71 through the machine, the tabs 41 in the wrapping of the panel and the locking grooves 75 in the side walls pass between the rocker arms 62-65. The latches 52-55 and the peaks 21 hold the side walls firmly against the sides of the mandrel 20. The clamps 66 and the extensions 69 on the rockers first come into contact with the tabs 41 on the shell 45. At this point , the annular flanges 70 of the pressing members 61 are extended outwardly away from the clamp 66 (as in Figure 9). The annular flanges 70 are then brought into contact with the central tabs 41 in such a manner that the annular openings within the flanges 70 are oriented directly above the openings 43 in the enclosure 45 and likewise oriented above the buttons 76 in the side wall 71. As the mandrel 20 continues its forward movement, the rocker pivots on its pivotal axes according to the movement of the mandrel so that the clamps 66 and the pressure members within them (61, 69 and 70) maintain their positions with respect to the openings of the side wall 75 and the wrapping tabs of the panel 41. As a result, the upper and lower rockers 62, 64 and 63, 65, respectively, compress the tabs 41 within the recesses of the slots 75 at the upper and lower ends of the side walls 71. In particular, the extensions 69 and the clamps 66 press the tabs 41 into the slots 75. This locks securely the tongues 41 in the grooves 75 by the action of the flanges 79. At the same time, the pressing members 61 with the annular flanges 70 push the openings 43 of the tongues 41 on the buttons 76 providing an even more secure fixation (see Figure 5 and 12). The last stage found by the forward moving mandrel includes a pair of hinged end plates 82 and 83, each plate having a set of clamps 91 imparting pressure thereto fixed thereto. Three such clamps 91 are shown in each of the plates 82 and 83. The clamps 91 operate in a manner that is similar (though not identical) to that of the pressure rockers 62-65. With reference to Figure 3 and the detail of the Figure 7, it is seen that each bracket 91 includes a bell-shaped outer extension 94 fixed to a T-shaped member 97 having an open end frame defined by the legs 98. Each bracket 91 includes a cylindrical pressure imparting member 101 having an annular opening defined by a flange 102, slidably mounted within the frame 98 of the open end. The pressure imparting member 101 is fixed to one end of a resilient member 99, in the form of a spring or other similar device, which in turn is captured within the opening defined by frame 98. The travel path of the member 101 is limited by a pin 103. Each frame 98 and extension 94 corresponds to a locking groove 77 in the side wall 72 and a tongue 42 in the upper part in the panel shell 45. The opening within the annular flange 102 corresponds to the buttons 78 in the annular walls 71, and to the openings of the tabs 43 in the opening panel 45. In operation, the panels 82 and 83 are closed so that the clamps 91 face the mandrel approaching 20 to as it pushes the parts of the container forward. Upon contact, the flared lower portion of the clamp extensions 94 push the tabs 42 into the slots 77. This securely locks the tabs 42 into the slots 77 by the action of the tabs 79. At the same time pressure members 101 with the annular flanges 102 push the openings 43 and the tabs 42 on the buttons 78 providing an even more secure attachment (see Figure 13). The already completed container is then ejected by an output power feeder (not shown). This feeder includes at least one slidably mounted member having a flange that extends upward and that oscillates between an extended and retracted position. When retracted, the flange catches against a lower edge of the newly formed container. As the member slides forward, it expels the container from the machine and then retrieves it to pick up the next container. The movement of the rockers 62-65 and of the pressure plates 82-83 is imparted through a cam and a cable system shown in Figure 6. the upper rockers 62 and 63 are mounted on a pivotal rod 121 and the lower rockers 64 and 65 are mounted on a pivot rod 131. The upper rod 121 is connected to sprockets 125 and adjustable links 126 to the cable 128 which guides the adjustable links 129 fixed to the cam pusher 130 which follows the cam 152 on rotating rod 150. Similarly, lower rod 131 is connected to sprockets 135 and adjustable links 136 to cable 138 which guides adjustable links 139 fixed to cam follower 140 which follows cam 151 on the rod 150. As the rod 150 rotates, so does the cam 151 and cam 152. When the cam followers 130 and 140 are moved by the cams 151 and 152, the links, cables and sprockets transmit this movement to the upper and lower rods 121 and 131, therefore move the rockers 62-65 forward. This movement is calibrated to coincide with the presence of the mandrel 20 transporting the casing 45 and the side walls 71 through the rocker arms. When the mandrel has passed through the rockers, the cam followers 130 and 140 move back towards their place (cams 151 and 152 that no longer impart movement), and the spring 149 moves the rockers 62-65 back toward their original positions. The movement of pressure plates 82 and 83 occurs in a similar manner. The plate 82 is fixed to a pivot rod 161 which is connected by adjustable links 162 to a cable 163 leading to adjustable links 164 and to a cam receiving the movement 175. Similarly, the plate 83 is fixed to a rod pivotal 171 that is connected through adjustable links 172 to a cable 173 which guides the adjustable links 174 and the cam pusher 175. As the cam 156 on the shaft 150 rotates, it imparts movement to the pusher 175. This movement is transmitted through the links and the cables to the rods 161 and 171 causing the plates 82 and 83 to move in such a manner that the pressure clamps 91 face the return mandrel 20. Upon contact with the mandrel, the pressure clamps cause the tabs 42 to be pushed into the slots 77 and the openings 43 to be pushed over the buttons 78. Once this is complete, the cam 156 is calibrated to move the pusher. of cam 175 and this movement is transmitted through the links and cables causing the pivot rods 161 and 171 to move the pressure plates 82 and 83 out of the way. This allows the newly formed container to be free to be thrown out of the machine. In the preferred embodiment, the side walls 71 can be made of molded polypropylene although other plastic materials, such as ABS, polystyrene, polycarbonates and nylon filled glass or non-plastic materials can be used. The panel envelope can be made of any suitable material including plastic, hard cardboard, corrugated cardboard or other suitable recicable material. The hoppers of the side wall and the high delivery guides as well as the vacuum supply must be angled to drive the lowest panel contained therein in the machine. The shoes 22 and 26 (and 24 and 28) must be positioned so that they are just above the surface 72 of the side walls 71 to assemble the side walls as they pass through the machine. Similarly, the shoes 23 and 27 (and 25 and 29) must be placed closer together than the shoes 22 and 26 (and 24 and 28) so that they are just above the position of the wrapper 45 once the tabs 41 have been pressed into the slots 75. The openings 43 in the wrapper 45 should be slightly smaller than the diameter of the buttons 76 and 78, but these buttons should be sharp and widened so that the openings 43 are easily pushed towards the buttons, but not easily removed. The extensions 69 must be sized to fit into the slots 75, and thus the tabs 79 hold the tabs 41 in place therein. Similarly, the flared extensions 94 should be sized to fit into the slots 77 so that the tabs 79 hold the tabs 42 in place therein. It is preferred that the mandrel be provided with a set of four capture pins 21 to hold the middle portion of the casing in one position while shaping the container. It should be understood that variations and modifications of the invention can be made without departing from the scope thereof. It should also be understood that the present invention should not be limited by the specific embodiments described herein, but only in accordance with the appended claims when read in the light of the following specifications.

Claims (20)

1. CLAIMS 1. An apparatus for molding containers of the type having two fixed synthetic side walls to a removable central panel wrap, characterized in that it comprises: (a) a moving mandrel mounted on a generally horizontal path between the retracted and forwardly extended positions; (b) a pair of units that supply side walls, located on opposite sides of the path; (c) an envelope feed of the panel located above the path; (d) a plurality of shoes and chisels for molding the container located around the path; (e) a plurality of side wall locks, located on opposite sides of the forward path of the delivery units; (f) a plurality of pivotally mounted pressure imparting rods located above and below the path in the vicinity of the locks; and (g) a pair of hinged terminal pressure plates located in front of the path. The apparatus according to claim 1, characterized in that each rocker that imparts pressure includes at least one extension and at least one compression clamp for pushing a tongue in the panel shell into a corresponding slot in one of the arms. side walls. 3. The apparatus in accordance with the claim 1, characterized in that each compression clamp supports at least one pressure-imparting, bevelled, spring-mounted and slidable member, the member has an annular flange extendable outwardly to push an opening in a slot in the wrapping panel over a button in a slot in the side walls. The apparatus according to claim 3, characterized in that a plurality of pointed peaks are provided at the forward end of the mandrel to engage with the synthetic side walls of a container to be assembled. The apparatus according to claim 1, characterized in that each of the terminal pressure plates includes a plurality of elongated mounted clamps, each of the clamps includes an opening at one of the ends and has a bell-shaped member. on the outer side thereof to push a tongue in the panel shell over a corresponding slot in one of the side walls. The apparatus according to claim 5, characterized in that a member that imparts cylindrical pressure, beveled, spring-mounted and slidable, is provided in the opening of each of the clamps, the member has an annular opening at one end for pushing an opening in a tab of the opening panel over a button in a slot of one of the side walls. The apparatus according to claim 1, characterized in that a plurality of primary shoes for molding a container are provided above and below the trajectory of the mandrel, each of the shoes includes an outwardly angled section to facilitate folding and the guide of the panel envelope while being pushed forward by the mandrel. The apparatus according to claim 7, characterized in that a plurality of secondary shoes are provided, each of the secondary shoes is immediately adjacent to the other and slightly outside the boundary of a primary shoe and each includes an angled section towards outside to facilitate the folding and wrapping guide of the panel as well as the guidance of the side walls as they are pushed forward by the mandrel. The apparatus according to claim 4, characterized in that a plurality of retractable, beveled spring locks are provided on each side of the mandrel path in the vicinity of the rockers to firmly press the side walls against each side of the mandrel. while it moves forward along the path for a secure placement as the rockers push the tabs on the wrapping panel into corresponding grooves in the side walls. 10. An improvement for a machine having a movable mandrel mounted on a generally horizontal path between retracted and extended positions for molding containers of the type having two fixed synthetic side walls to a removable central wrapping panel using tabs and locking slots, the improvement is characterized in that it comprises a plurality of pivotally mounted pressure springs located above and below the path, each pressure beam includes at least one extension and at least one compression clamp for pushing a tongue in the body. opening panel within a corresponding slot in one of the side walls. 11. The improvement in accordance with the claim 10, is characterized in that each compression clamp has an aperture for holding a sprung-mounted and slidable bevelled pressing member, having an annular flange extending outwardly to push an opening in the tongue over a button in a slot in one of the side walls. The improvement according to claim 11, characterized in that a plurality of beveled retractable spring locks are provided on each side of the mandrel path in the vicinity of the rockers to firmly press the side walls against each side of the mandrel while a as it moves forward along the path for a secure placement as the rockers push the tabs on the opening panel into corresponding grooves in the side walls. 13. The improvement in accordance with the claim 10, characterized in that a plurality of pointed peaks are provided at the forward end of the mandrel to engage with the synthetic side walls of a container to be molded. 14. The improvement in accordance with the claim 11, characterized in that a plurality of primary shoes for molding a container are provided above and below the trajectory of the mandrel, each of the shoes includes an outwardly angled section to facilitate folding and the wrapping guide of the panel while this is pushed forward by the mandrel. 15. The apparatus according to claim 14, characterized in that a plurality of secondary shoes are provided, each of the secondary shoes is immediately adjacent to the other and slightly protruding from the limits corresponding to the primary shoe and each one includes a section angled outwards to facilitate the folding and guiding of wrapping of the panel as well as the guide of the side walls while these are pushed forward by the mandrel. 16. The improvement according to claim 11, characterized in that a pair of pivotally mounted end pressure plates are provided at the forward end of the path, each plate includes a plurality of clamps mounted in elongated form, each clamp includes an opening at one end and has a bell-shaped member on the outer side thereof for pushing a tongue on the wrapping panel over a corresponding slot in one of the side walls. 17. The improvement according to claim 16, characterized in that a member that imparts cylindrical pressure, beveled, mounted in springs and is slidable is provided in the opening of each of the mounted clamps, the member has an annular beech at one end for pushing an opening in a tongue in the shell of the panel over a button in a slot of the side walls. 18. An improvement for a machine having a movable mandrel mounted on a generally horizontal path between retracted and extended positions for molding containers of the type having two fixed synthetic side walls to a removable central panel wrap using tabs and locking slots, the improvement is characterized in that it comprises a pair of terminal pressure plates mounted pivotally at the forward end of the path, each plate includes a plurality of clamps mounted in elongated form, each of the clamps including an opening at one end and having one end in the form of a fixed bell on the outer side thereof for pushing a tab of the panel envelope over a corresponding slot in one of the side walls. 19. The improvement in accordance with the claim 18, characterized in that a member that imparts cylindrical, bevelled, spring-mounted and slidable pressure is provided in the opening of each of the assembled clamps, the member has an annular opening at one end for pushing an opening in the wrapping groove of the panel over a button in a groove of the side walls. A method for molding containers of the type having two fixed synthetic side walls, by locking tabs and slots, to a removable central panel wrap using a machine having a movable mandrel mounted on a generally horizontal path between retracted and extended positions characterized in that it comprises the steps of: a. Retract the mandrel to one end of the trajectory; b. move the mandrel along the trajectory; c. delivering two synthetic side walls to the sides of the moving mandrel going forward from the hoppers located on opposite sides of the path; d. delivers the central panel wrap in front of the moving mandrel going forward from a feed above the mandrel path; and. unmolding a panel wrap around the side walls while the mandrel moves forward through a plurality of shoes and chisels located along the trajectory of the mandrel; F. pressing the tabs on the panel envelope into the corresponding slots in the side walls to connect them together for molding and container; and g. eject the recently molded container out of the machine. SUMMARY A new machine to mold strong, durable and recyclable containers of the type described in US Patent No. 5,497,939 is described, without the use of adhesives or nails, which are ready to be loaded, closed, stacked and shipped. The machine uses a mobile mandrel mounted on a path between retracted and extended positions. As the mandrel moves forward, it first receives two side walls 10 of the container to be assembled, which are firmly compressed against the walls of the mandrel while it moves forward. The mandrel immediately finds the frame of the panel or envelope of the container to be assembled, the envelope includes a plurality of 15 tabs along the edges of their longer sides corresponding to the locking grooves in the side walls. As the mandrel moves forward, it pushes towards the center of the wrap, where a set of shoes and chisels folds the upper and lower portions 20 of the wrap towards a more horizontal orientation, leaving the middle part of the wrapper in a vertical position. As the mandrel pushes the wrapper through the machine, a set of upper and lower moving rocker arms that contain unique pressure mechanisms, 25 press the tabs of the horizontally oriented portion of the casing into the locking slots at the ends of the side walls. When the mandrel is fully extended, pressure is applied to the tabs of the vertically oriented middle section of the casing to mold the bottom of the container using a pair of hinged pressure plates, adapted by unique bevelled clamps. The side walls are then released by the mandrel, the hinged end plates are opened and the resulting container, 10 is removed from the machine. The mandrel is then fully retracted so that the machine starts another cycle.