US2738714A - Mechanism for folding container end flaps - Google Patents

Description

March 20, 1956 P. E. FISCHER l-TAL 2,738,714

MECHANISM FOR FOLDING CONTAINER END FLAPS Filed March 31, 1952 5 Sheets-Sheet 1 Ba. 2 Ha.

5) MP W r gpy y March 20, 1956 P. E. FISCHER ETAL 2,733,714

MECHANISM FOR FOLDING CONTAINER END FLAPS Filed MarOh 31, 1952 5 Sheets-Sheet 2 March 20, 1956 P. E. FISCHER ETAL 2,738,714

MECHANISM FOR FOLDING CONTAINER END FLAPS Filed March 31, 1952 5 Sheets-Sheet 3 iwzxvruks P404 .5 FISCHER P054507 5. f/Efll/Y (was: 5/4/6N50/V flan 2y E MssM/m P. E. FISCHER ET AL 2,738,714

March 20, 1956 MECHANISM FOR FOLDING CONTAINER END FLAPS 5 Sheets-Sheet 4 Filed March 31, 1952 HGJO March 20, 1956 P. E. nscHER EFAL MECHANISM FOR FOLDING CONTAINER END FLAPS Filed March 51, 1952 United States Patent MECHANISM FOR FOLDING CONTAINER END FLAPS Paul E. Fischer, Minneapolis, Robert S. Hedin, St. Paul,

Charles H. Swanson, Minneapolis, and Henry E. Wzssman, St. Paul, Minn., assignors to General Mills, Inc., a corporation of Delaware Application March 31, 1952, Serial No. 279,617

17 Claims. (Cl. 93-36.8)

The present invention relates to improvements in devices for folding closing flaps over the end of a container.

In an automatic machine of this type, the previously formed container, with closure flaps extending from the side walls of the container, is positioned relative to mechanical folding elements whereupon the elements proceed to fold the closure flaps into the plane of the container end. A machine of this general type is shown in the co-pending patent application, Mechanism for Making Containers, Fischer, Hedin, Swanson and Wissman, Serial No. 279,615, filed March 31, 1952. In this machine, the formed containers are carried on a rotatable turret which is indexed to carry the containers opposite folding stations. At each of these folding stations is positioned automatic and flap folding mechanism. The turret halts the container briefly at each station to permit the folding mechanism to perform a folding function on the container and then indexes to move the container to a succeeding station where it receives additional folding.

In these automatic packaging machines, speed is of the essence and is a prime object in the design of the machine. To obtain speed in the mechanism of the type described, it is necessary that at each station the folding mechanism complete its function as rapidly as possible so that the container may be quickly carried onto the next folding station. Also, in order to reduce the number of stations, the folding mechanisms should perform as many functions as possible within the brief time the container is positioned before the station. Folding devices which have short paths of travel and rapid movement are necessary to accomplish folding without wasted movement and consequent waste of time. However the speed and direction of movement must be such that the folding friction is properly done without damaging the container. The present invention contemplates operation on a container formed of a thin layer of metallic foil coated with a layer of thermoplastic adhesive. Metallic foil, while yielding many advantages to the container formed, presents many problems in the formation of the container in that the material is extremely soft and pliable and, when engaged by a fast moving folding member, is likely to wrinkle, tear or uncontrollably bend. Deformations, such as wrinkles, bends or tears in the material, destroy the attractiveness and efiectiveness of a container.

Therefore, the present machine includes among its objects the provision of a device for folding the end flaps of a metallic foil container which will accomplish a maximum number of folding functions with speed and rapidity and yet accomplish these folding actions with sufficient gentleness to avoid the danger of damaging the soft container material.

Another object of the invention is to provide a device with folding elements having shortened paths of motion and which are in engagement with the flaps to be folded for a large portion of their travel in order that they may yieldthe most gentle action within the period of time available for folding.

2,738,714 Patented Mar. 20, 1956 ice Another object of the invention is to provide a folding mechanism which will fold container end flaps which are attached to opposing side walls over the end of the container and fold and heat seal a thermoplastic coated cover flap attached to an intermediate side wall of the container over the end flaps to hold them against the container end.

Another object of the invention is to provide a device for folding and heat sealing a thermoplastic coated cover flap over the end of the container, obtaining an improved seal between the carton and cover flap.

A further object of the invention is to provide an improved mechanism for operating folding elements and carrying them along the path of motion whereby they accomplish folding of a plurality of end flaps in a minimum of time without interference of their paths of motion.

Other objects and advantages will become apparent from the following specification and drawings in which:

Figure 1 is a perspective view of the container which is to have its end flaps folded and sealed into the plane of its end;

Fig. 2 is a side elevation of a mechanism for folding the carton flaps;

Fig. 3 is an enlarged side elevation, being partially in section, showing the action of the folding shoes in folding the side flaps over the container end;

Fig. 4 is a front elevation of the mechanism for folding the carton end flaps;

Fig. 5 is a sectional View taken along line 55 of Fig. 4;

Fig. 6 is a sectional view taken along line 6-6 of Fig. 2;

Fig. 7 is an enlarged perspective view of the tiltable platform for carrying the cover flap folding elements;

Fig. 8 is a plan view illustrating the action of the side flap folding shoes;

Fig. 9 is a plan view illustrating the position of the folding shoes after the side flaps have been folded;

Fig. 10 is a perspective view of the carton showing the condition of the end flaps after being folded by the flap folding shoes;

Fig. 11 is an enlarged side elevation illustrating the motion of the cover flap folding head;

Fig. 12 is a front elevation of the folding head having portions broken away to illustrate the mounting of the roller; and

Fig. 13 is a perspective view showing the container with the end flaps completely folded.

Referring to Fig. 1, the container 20 is shown having end flaps 22 and 24 attached to the opposing side walls 26 and 28. The container has been previously formed in any desired manner. It may be formed as illustrated in the co-pending patent application, Mechanism for Making Containers, Fischer et al., Serial No. 279,615, filed March 31, 1952. A cover flap 30 is attached to an intermediate side wall 32 and has a coating 34 of thermoplastic adhesive on its inner face. The container which is shown is made preferably of metallic foil or of laminations including metallic foil, although it will be seen from the description that the machine, providing the principles of the invention, could be used to fold the end flaps of any well known type of container. The container which is shown has had one of the end flaps 36 previously folded across the container end and the remaining flaps 22, 24 and 39 are to be folded to overlie this flap and complete the closure. In the illustrations, the closure is at one end of the container with the opposing end remaining open, but the mechanism shown can be used for closing the flaps at either end.

As shown in Figs. 2 and 3, the container is supported in a horizontal position on a mandrel 38, over which the container has been formed. The end flaps 22 and 24 on the side project outwardly from the end of the carton and the cover flap 30 depends downwardly from the lower wall 32. An ejector 40 abuts the inner side of the end of the container to form a fiat surface for supporting the flaps as they are folded across the container end. This ejector plate 40 is carried on a shaft 42 slidably mounted within the mandrel 38. The ejector plate and shaft are provided to strip the container from the end of the mandrel when the folding operations are completed. The mandrel may be supported on any well known type of conveyor, preferably a revolving turret 44 which is capable of carrying it to the position shown in Fig. 2. opposite the folding mechanism, and to succeeding folding niec ianisms.

The folding mechanism is supported beside the revolving turret on a stationary framework 46. To operate the folding mechanism, a cam shaft 48 carries a plurality of driving mechanisms, such as cams, and a spro .et, all operated in synchronism with the turret, to fold .e container when it is brought into position by the turret.

The first operation to be performed on the container is to fold the end flaps 22 and 24 inwardly into the plane of the carton end to a position shown in Fig. 10. To accomplish this, a pair of folding shoes 50 and 52, Figs. 2, 3, 8 and 9, are normally positioned outwardly from the container end, as shown in the solid line position of Figs. 2 and 8. in this position, the shoes are spread widely apart from each other. The shoe 52 is supported on an arm 54 and a second parallel arm 56, the arms being pivotally connected to the shoe at their outer ends. Arm 54 is pivoted at its inner end on a cross head 58 (Figs. 4 and 8) and arm 56 is pivotally mounted and is vertically slidable on a fixed post 60. These arms, with the shoe, constitute a parallelogram linkage and, when carrying the shoe from the solid to the dotted line position of Fig. 8, keep the outer face 62 of the shoe parallel to the end 64 of the container. The shoe 50 is carried in a similar manner, being supported on arms 66 and 68 which are pivotally connected to the shoe at their outer ends, the arm 66 being pivotally connected to the cross head 58 at its inner end and the arm 68 being splined to a pivotally mounted shaft 70 at its inner end. This linkage also forms a parallelogram and, when carrying the shoe 50 from the solid to the dotted line position of Fig. 8, maintains it parallel to the end 64' of the container. The shoes are arranged to swing together to fold the container end flaps and to return to normal position in unison. To accomplish this, a pair of meshing segment gears 72 and 74- are secured to the arms 68 and 56.

The splined post 70 is pivotally mounted in the bearing 76 which is carried on a vertical framepiece 79 and is pivotally mounted at its base in the bearing 78 on the main frame 46. The adjacent post 60, extending parallel to it, is fixedly mounted in similar supports, the upper end being supported in a boss 80 carried on a vertical framepiece 81 and the lower end in a boss 82, both carried on the main frame 46. A setscrew 83 secures the post 60 in the boss 82. To give motion to the arms carrying the folding shoes, the vertical splined post 70 is oscillated by means of a crank 84 secured to the post and pivoted by a rod 86, as is shown in detail in Fig. 5. The crank 84 extends outwardly through a slot 83 in the vertical framepiece 79. The connections on both ends of the rods 86 are formed of ball and socket connectors, as shown at 89 (Fig. Reciprocal movement of the rod 36 swings the crank 84 from the dotted line position of Fig. 5 to the solid line position, carrying the folding shoes 50 and 52 inwardly to folding position. The push rod 86 is reciprocated by the pivotal movement of a large bell crank 90, pivotally hung on the main frame on a shaft 92 which is journaled in the framework (Figs. 2 and 4). At the lower end of the bell crank is a follower 94 which rides in a track 96 on cam 98, mounted on shaft 43. The path of this cam trackis indicated by the broken lines of Fig. 2, and also numbered 98. The center of the follower which follows the cam track and the upper end 4 of the bell crank are both labeled B, for ease in following the drawing.

Fig. 2 illustrates the follower at a high portion of the cam, with the bell crank pivoted to the left, drawing the crank arm 84 to the left and holding the folding shoes 50 and 52 in spread position. As the cam shaft 48 rotates clockwise, the follower 94 moves to a lower portion of the cam track 96 (shown by the path 98) and the folding shoes are moved in an arcuate path, as indicated by the arrows in Fig. 8, toward the container end, through the flap engaging position indicated by the dotted figures 97 of Fig. 8 and together to the position shown in Fig. 9. At that point, the flaps 22 and 24 will have been folded against the container end and pressed fiat thereagainst to bring the container to the condition shown in Fig. 10. if the flaps are such that the tips overlap, interference is sometimes had between the flaps as they come together. If this is undesirable, it can be overcome by either making one of the shoes 50 or 52 longer, so as to fold one flap ahead of the other, or by advancing the position of one of the shoes.

The next step in the folding of the container end flaps is to bring the cover flap 30 over the folded flaps 22 and 24 in such a manner that the flaps can not spring outwardly. To do this, the folding shoes 50 and 52 are slid laterally, in a vertical direction, off the end of the container. Closely following this movement and before the flaps have a chance to spring outwardly, the folding head 102 follows the shoes in close adjacency and folds the cover flap over the side flaps.

To raise the shoes and slide them off the end of the container, the crosshead 58 is slid upwardly on the rods 60 and 70. During this movement, the shoes are kept close together. The crosshead (Fig. 4) consists of two horizontal plates 104 and 106, both slidable on the posts and holding the inner ends of the arms 54, 56, 66 and 68 between them. The plates 104 and 106 have vertical bolts 10S and 110 passing through their ends, which serve as pivotal shafts for the inner ends of the arms 54 and 66 and which hold the plates 104 and 1106 together. A rod 112 is pivotally pinned to projections on the lower plate 106 and pivotally connected at its lower end to a rocker arm 114 mounted for pivotal movement on the shaft 92. A collar 115, secured to the shaft 92, prevents the rocker arm 114 from sliding along the shaft 92. For ease of following the drawing, the rod 112 is shown diagrammatically by broken lines of Fig. 2. The rocker arm carries at it inner end a follower 116 which rides in the track of a cam 118, the track being indicated by the broken lines, also numbered 118, of Fig. 2. For ease of following the drawing, the ends of the rocker arm 114 and the upper end of the push rod 112 are labeled A. Fig. 2 shows the shoes in their normal lowered position, both in the solid line position and the broken line position numbered 121. After the shoes have moved toward the broken line position 121 of Fig. 2, against the end of the container, the cam 118, rotating with shaft 148, in its clockwise rotation rocks the rocker arm 114 clockwise to raise the crosshead 58 and slide the shoes off the end of the container, moving them to a raised position. As this is occurring, the folding head 102 is moving up behind it, laying the cover flap 30 of the container over the folded flaps 22 and 24 before they are released by the shoes.

The folding head (Figs. 2, 11, and 12) has a fiat flapcontacting face 122 and is carried at the top of a vertical support 124 which is secured to a crosshead 126 (Fig. 6), slidable on vertical ways 128. These ways constitute rods mounted upright on a pivotal platform 130, which is shown in detail in Fig. 7. The platform is pivotally mounted on the frame by trunnions 132 and given pivotal movement by a crank 134 which is bolted to the side of the platform by bolts 136. These bolts may extend from elongated holes in the bellcrank so that the crank may be angularly adjustable with respect to the platform 130. The platform is normally held in a horizontal position, as shown in Fig. 2, to maintain the folding head 102 with the folding face 122 substantiallyin the plane of the container end. The platform is rocked by means of the bellcrank which has at its lower end a follower 138 which rides in the track of the cam 140, carried on the main shaft 48. The path of this cam track is indicated by the broken lines also numbered 140. For convenience of reading the drawing, the platform, the follower, and the folding head, in their uppermost positions, are labeled; in Fig. 2 with a C. To move the folding head up behind the folding shoes, as they are raised, and to engage the cover flap 30 with the fiat face 122 of the head, the crosshead 126 is slid upwardly along theways 128. To this end, a pitman142 (Figs. 2 and 6) is pivotally connected to 'a crosshead 126 at its upperend and to the crank 144 at its lower end. The crank is mounted to rotate with a shaft-146 supported on brackets 148. Secured to the shaft between the brackets is a sprocket 150, carrying the chain 152 which is driven from a sprocket 154 mounted on the main cam shaft 48. The chain is engaged by a tightener sprocket 151 on adjustable shaft 153. i

As the crank 144 rotates clockwise, as shown in Fig. 2, the crosshead moves upwardly, carrying the folding head over the cover flap 30 to fold it over the flaps 22 and 24, in the manner shown in broken lines 156 of Fig. 11. The face 122 is heated by'the elements 158, which are mounted in the head (Fig. 12), and are supplied by electricity through leads 160. This heated face softens the thermoplastic adhesive on the cover flap to cause it to adhere to the flaps 22 and 24 and to the exposed container end 36. As the head moves to its uppermost position, passing ofi the cover flap, the roller 162 rolls against the flap, pressing it tightly against the container end to squeeze the thermoplastic adhesive 34 into the pores and crevices of the container to cause the flap to adhere tightly against the end. This roller is not heated and causes some cooling of the adhesive which makes the flap adhere to the container end while the air completely solidifies the thermoplastic. The roller is carried between projections 164 on the lower side of the head. Conicalshaped bearings 166 (Fig. 12) are threaded into the projections and extend into mating conical recesses 168 in the roller ends to provide a support for the rotating roller.

The entire head is pivotally mounted at the top of the vertical support 124, as shown in Figs. 6 and 11, being supported on a pin 170, carried between projections 171 at the upper end of the support 124. At the rear end of the head are extensions 172 across which extends a pin 174. Between this pin and a bolt 176, carried by a bracket 178 on the vertical support 124, is a coil tension spring 180. This spring urges the head to pivot counterclockwise and tensions the rollers 162 tightly against the container end as the head is moved upwardly. To provide a stop to limit the pivotal movement of the head, an insulating block 175 is held against the vertical support 124 by bolts 177, threaded into a clamping piece 179. The position of the head, as it is moved upwardly, is such that the smooth face 122 slides over the cover flap 130, pressing it snugly against the end of the container. The roller 162 projects slightly beyond the fiat face 122 and engages the cover flap very firmly, causing the head to pivot slightly in a clockwise direction as the roller engages the container end.

As the top of the head reaches its uppermost position, indicated by the point numbered 182 in Fig. 11, the folding shoes begin to spread apart so that the head can drop back along the path indicated by a broken line 184 in Fig. 11. The head, in moving back along this path to the dotted line position of Fig. 11, moves between the shoes which are retracted and spread apart in the dotted line position 186 of Fig. 2. To spread these shoes and permit the head to move between them, a rotation of the cam shaft 48 rocks the bellcrank B counterclockwise to rotate the splined shaft 70 and outwardly swing the arms supporting the shoes. At this point, the cam 138 begins to reach a high point in the path of the cam track 140 to pivot or tilt the platform counterclockwise, or to the left, as shown in Fig. 2, thereby carrying the head back to the dotted line position 188. The platform begins to tilt the head back just as it reaches its uppermost position and, therefore, the head has already begun to move down when it reaches position '188. The downward movement of the head continues with the rotation of crank 144' until the crosshead reaches its lowermost position and is again tilted forward to the normal position shown in Fig. 2.

It is believed that the complete operation of the machine will be fully understood from the foregoing description. However, a brief review of the motion of the folding elements will be given.

As the container is moved into position opposite the folding shoes 58' and 52, the shoes are moved arcuately toward the container end. As the shoes move together, the end flaps 22 and 24 are forced over the container end. With the shoes remaining together, they are slid laterally upward off the container end with the folding head 102 following behind the shoes in close proximity. The heated face 122 engages the cover flap 30, folding it gently over the folded flaps before they are released. This contact also softens the thermoplastic adhesive and the roller 162, being held tightly against the cover flap 30 by the spring 180, presses the adhesive tightly between the layers to cause the flap to adhere to the container end. As the folding head reaches its uppermost position, it is moved away from the container end to pass between the shoes 50 and 52, which have been spread. The spreading of the shoes serves the purpose of moving the shoes back to normal position, preparing them for a new folding stroke and allows the heat to pass between them and perform its function while in close proximity to the shoes,

although avoiding interference with them. The shoes and the head will then drop downwardly to normal position to be ready for a new container to be moved in position. The complete container is shown in Fig. 13, having the end flap 30 folded and sealed across the end. This finished container is then carried away from the station as the turret rotates and a new container with unfolded flaps is moved into position.

Thus it Will be seen that we have provided a mechanism for smoothly and quickly folding the flaps over the end of a container and sealing the cover flap to the container end with thermoplastic adhesive. The motions of the folding elements are short and each motion is for the sole purpose of achieving a better and more speedy fold, yet the motions and positions of the shoes are so arranged that they may independently perform their own functions without interference with each other.

We have, in the drawings and specification, presented a detailed disclosure of the preferred embodiment of our invention, but it is to be understood that as the invention is susceptible of modifications, structural changes and various applications of use Within the spirit and scope of the invention, we do not intend to limit the invention to the specific form disclosed but intend to cover all modifications, changes and alternative contructions and methods falling within the scope of the principles taught by our invention.

We claim as our invention:

1. A mechanism for folding the end flaps of a container comprising means for supporting a container having end flaps joined to opposing side walls and a cover flap joined to an intermediate wall, at least one folding shoe mounted opposite the container top, first means for moving said shoe into the plane of the container top in an arcuate motion to fold the cover flap against the container top, and second means for moving said shoe in a path parallel to said opposing container walls while said first means holds the shoe in the plane of the carton top.

2. A mechanism for folding the end flaps of a container comprising means for supporting a container having end flaps hingcdly attached to opposing sidewalls of a container, a pair of folding shoes mounted outside the plane of said side walls and opposite the container end, the shoes having a folding face lying in a common plane parallel to the container end, means for moving said shoes in an arcuate motion from normal position to folding position with the faces moving into the plane of the carton end, and means moving the shoes in a path at right angles to the plane defined by the shoes in their first motion to leave the flaps with a sliding motion.

3. A mechanism for folding the end flaps of a container comprising means for holding a container having end flaps articulated to side walls of a container, a pair of folding shoes positioned opposite the container and spread apart in normal position, first means for moving the shoes into the plane of the container top and together to fold the flaps over the container end, and second means for moving the shoes laterally off the container end while the shoes remain in the same relative position to each other obtained by the action of the first means, and said first means spreading the shoes before they are returned to normal position.

4. A mechanism for folding the end flaps of a container comprising means for supporting a container having end flaps attched to opposing carton side walls, a pair of folding shoes spread apart in normal position, a first means for moving each of the shoes in an arcuate path into the plane of the carton end into engagement with one of said end flaps and together to fold the flaps, and a second means for sliding the shoes off the carton end while remaining together and in the plane of the carton end, said first means spreading the shoes after they are slid from the carton end and said second means returning the shoes to normal position when they are spread.

5. A mechanism for folding the end flaps of a container comprising means for supporting a container having opposing end flaps, first and second folding shoes, 21 pair of ways, one of which is rotatable and splined, a crosshead mounted for sliding on the ways, a pair of parallel supporting limbs for the first shoe pivotally attached thereto and pivotally mounted on the crosshead to form a parallelogram linkage with the shoe being parallel to the container end, similar parallel links similarly attached to the second shoe with one of the links pivotally attached to the crosshead and the other attached to pivot with and slide on the splined shaft, first means for rotating the splined shaft to cause the shoes to be carried together and into the plane of the carton top, and second means for sliding the crosshead along the shafts while the splined shaft is not rotating to laterally slide the shoes olT the carton top.

6. A mechanism for folding the end fiap of a container comprising means for supporting a container having a cover flap attached to a side wall, a folding member, reciprocable means supporting the folding member, means giving continual motion to said reciprocable means to move the member in one direction in the plane of the container top and fold the cover flap over the container, a pivotally mounted member carrying said supporting memher, and means for pivoting said pivotally mounted memher to move the folding member away from the container top in the other direction of reciprocation.

7. A mechanism for folding the end flap of a con tainer comprising a holder for supporting a container having a coverflap attached to the end of a side wall, a folding member for engaging the flap and folding it over the end of a container, at crosshead supporting the folding member, ways on which the crosshead is reciprocated, a platform supporting said ways and mounted to pivot about an axis parallel to the end wall of the container, means to reciprocate the crosshead, and means to pivot the platform to move the folding member away from the container end when the crosshead is moving in one direction and to pivot the folding member into the plane of the carton end when the cross head is moving in the other direction.

8. A mechanism for folding the end flap of a container comprising a holder for supporting a container in horizontal position having a cover flap attached to the end of the lower side wall, a folding member for engaging the flap and folding it over the end of a container, a crosshead supporting the folding member, ways on which the crosshead is reciprocated, a platform supporting the ways and mounted to pivot about an axis parallel to the end wall of the container, the platform positioned outside the plane of the container end, means to pivot the platform to move thhe folding member into the plane of the container end to fold the cover flap and away from the plane of the container end, and means for elevating the crosshead to fold the flap when the folding member is in the plane of the container end and for lowering the crosshead when the crosshead is being pivoted away from and back into the plane of the container end.

9. A mechanism for folding the end flaps of a container comprising means for supporting a container having end flaps joined to opposing side walls and a cover flap joined to an intermediate side wall, a pair of folding shoes for folding the end flaps over the container end and a cover flap folding element for folding the cover flap over the end flaps, means for moving the shoes together into the plane of the carton end and into engagement with the end flaps to fold the flaps against the container end subsequently laterally off the container end while keeping the shoes together in said end plane, and means for moving the folding element in close succession to said lateral motion of the shoes and in the same direction to fold the cover flap over the folded end flaps.

10. A mechanism for folding the end flaps of a con tainer comprising means for supporting a container having end flaps joined to opposing side walls and a cover flap joined to an intermediate side wall, a pair of folding shoes for folding said end flaps, a folding member for folding said cover fiap over the container end, means to move said shoes together and into the plane of the container end to fold the end flaps to move the shoes laterally off the container end and to move the shoes apart to permit said folding member to pass between them, and means moving said folding member laterally in the plane of the container end to fold the cover flap and subsequently moving the folding member away from the container between the separated shoes.

11. A mechanism for folding the end flaps of a container comprising means for supporting a container having end flaps joined to opposing side walls and a cover flap joined to an intermediate side wall, a pair of folding shoes for folding the end flaps over the container end, and a cover flap folding element, first means for moving said Shoes in an arcuate path together and into the plane of the container end to fold the end flaps, second means to move the shoes laterally off the container end, said first means subsequently moving the shoes apart and away from the plane of the container end, first element actuating means moving the folding element in the plane of the container end in close proximity to the shoes as they are moved laterally off the container, and second folding element actuating means carrying the element back between the shoes after the end flap has been folded.

12. A mechanism for folding the end flaps of a container comprising means for supporting a container having end flaps joined to opposing side walls and a cover flap joined to an intermediate side wall and coated with a thermoplastic adhesive, a pair of folding shoes for folding the end fiaps over the carton end, and a cover flap folding element, means for heating the cover flap folding element to soften the thermoplastic adhesive, means for moving the shoes together into the plane of the container end and into engagement with the end flaps to fold the flaps against the container and subsequently moving the shoes laterally off the container end while lteeping them together and in said end plane to hold the end flaps in place, and means for moving the folding element in close succession to said lateral motion of the shoes and in the 1silame direction to fold the cover flap over the folded end aps.

13. A mechanism for folding the end flaps of a container comprising means for supporting a container .in a horizontal position, the container having end flaps connected to the vertically positioned side walls and a thermoplastic coated cover flap connected to the lower side wall, a pair of side flap folding shoes horizontally spaced from the end of the container, a heated cover flap closing element positioned below the container, a first shoe actuating means moving the shoes together into the plane of the carton end to fold the side flaps over the carton, a second shoe actuating means moving the shoes vertically off the end of the container in the plane of the container end, a first element actuating means moving thhe folding element upwardly in the plane of the container end to fold the end flap over the end of the container and seal it thereagainst with the softened thermoplastic adhesive, said second shoe actuating means moving the shoes apart, and a second element actuating means moving the folding element away from the carton end between the separated shoes.

14. A mechanism for folding an end flap of a container comprising a holder for supporting a container having a cover flap hingedly attached to a sidewall, a folding member for folding the cover flap over the end of the container, a folding block having a fiat flap-engaging face and mounted on the folding member, a rotatably mounted roller resiliently mounted on the folding member adjacent the block, means biasing the roller toward the container, and means for moving the folding member across the container end in a direction to cause the flat face to first engage and fold the flap over the container end and with the roller following the flat face .into engagement with the flap to roll it against the container end.

15. A mechanism for folding an end flap of a container comprising means for supporting a rectangular container having a cover flap articulated to a side wall, a folding head for folding the cover flap over the end of the container having a flap engaging face and a roller positioned adjacent the face, means for pivotally supporting the folding head, means for moving said supporting means in a path parallel to the plane of the container end with said face in the plane of the container end to engage and fold the cover flap over the carton followed by the roller engaging and pressing the flap to the container end, biasing means urging the folding head to pivotal movement to press the roller against the container end, and stop means for limiting the pivotal movement of the folding head.

16. A mechanism for folding the end flaps of a container comprising means for supporting a rectangular container having a cover flap articulated to a side wall and having thermoplastic coating on its inner face, a folding head for folding the cover flap over the end of the container having a flap engaging face and a roller posi tioned adjacent the face, means for pivotally supporting the folding head, means for heating the face to soften the thermoplastic adhesive on the flap, means for moving said supporting means in a path parallel to the plane of the container end with said face in the plane of the container end to engage and fold the cover flap over the carton followed by the roller engaging and pressing the flap to the container end, biasing means urging the folding head to pivotal movement to press the roller against the container end, and stop means for limiting the pivotal movement of the folding head.

17. A mechanism for folding the end flaps of a container comprising a holder for supporting a container having a thermoplastic coated cover flap attached to its side wall, a folding member for supporting flap-folding elements, a flap engaging folding block mounted on said member and having a flat face for folding the cover flap over the end of the container, means to heat the face for softening the thermoplastic adhesive, a flattening roller for rolling over the folded flap, said roller mounted on a support pivotally mounted on the folding member, biasing means resiliently urging the roller support to pivot the roller toward the container end, and means to move the folding member past the container end moving the face in the plane of the container top into engagement with the flap to fold it over the container and moving the resiliently mounted roller in the plane of the container end in close succession to the face to flatten the heated cover flap against the container end.

References Cited in the file of this patent UNITED STATES PATENTS 1,275,756 Rose Aug. 13, 1918 1,280,364 Armstrong Oct. 1, 1918 1,481,757 Stokes Jan. 22, 1924 1,872,488 Miller Aug. 16, 1932 1,965,897 Iurgens et al July 10, 1934 2,257,689 Jungmayr Sept. 30, 1941 2,358,455 Hallman Sept. 19, 1944

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