Machine For Sealingly Closing Containers By Means Of Covers

Abstract

Machine for sealingly closing containers each provided with an upper outwardly projecting collar, by means of a cap which is applied on the said collar, comprising container-conveying means adapted to drive the containers along a first circular path, cap-conveying means adapted to convey the containers along a second circular path tangent to the first path and arranged above the latter, so that each cap travelling along the second-path portion is located above a container and moves by gravity onto its collar, and fixing means adapted to secure a cap on each container.

Description

The present invention relates to an automatic machine for sealingly closing containers by means of covers, in particular for closing containers provided at their upper portion with a collar projecting outwardly, by means of a cap which is applied on the said collar and then secured on the latter.

A great number of products, in particular food products such as ice-cream, yogurt, etc., are marketed in containers which are closed sealingly by means of covers in the form of caps, i.e., plane blanks cut out of low-melting-point heat-material based, in most cases, on aluminium. Each cap is generally provided with an ear or tongue which facilitates the opening of the container by stripping the said cap. Such a container is generally in the form of an upwardly flaring cup or small boat-shaped receptacle made from a material identical with that of the said blanks, the said cup or the like being provided with an upper flange folded outwardly so as to form an annular collar. The latter may be either plane or provided with a peripheral bead projecting upwardly, so as to form a kind of socket in which is placed the cap. The cap, whose dimensions substantially correspond to those of the collar, is secured on the latter by any known means such as, for instance, heat-sealing.

Heretofore, the caps were manufactured by means of a cutting punch separate from the machine serving to pack the product, and were stacked in receptacles which were thereafter placed on the said packing machine. Each cap was then seized by a gripping device provided with suction grips, the motions of which were synchronized with that of the packing machine, so that the said cap, after being seized at the foot of the stack by a suction grip was turned over and then laid onto the container to be closed. Such suction-grip systems involve a certain number of drawbacks. The necessity of creating a vacuum in the suction grip to seize the caps compels to provide for a source of vacuum connected through conduits with each suction grip, i.e. a delicate and expensive equipment. Moreover, when a suction grip does not correctly seize a cap or lets it escape, and then arrives above a container filled with the product to be packed, it sucks the product and is obstructed thereby, thus, of course, being prevented from further normal operation. The machine has then to be stopped and the sucking grip cleaned in order that it may operate again.

The machine according to the present invention is designed to avoid the aforesaid drawbacks and is characterized in that it comprises, in combination with rotatable container-conveying means adapted to receive the said containers individually and continuously drive them along a first circular path, mechanical cap-conveying means adapted to receive the caps individually and to continuously convey them along a second circular path tangential to the first path and extending above the latter, the said container-conveying means and cap-conveying means being driven in synchronism by a common drive member, so that each cap travelling along the second-path portion overlying the first path in proximity to the point of tangency, is located above a container and moves down by gravity onto its collar, and fixing means adapted to fix the cap on the associated container, the said fixing means being arranged above the containers and solid with the said rotatable container-conveying means.

The machine according to the invention therefore performs a distribution of the caps on the containers by purely mechanical means and thus eliminates the drawbacks of the machines using vacuum and sucking-grip systems.

The conveyance of the containers and caps along two tangent and superposed paths may be performed by rotatable means driven in continuous motion, i.e., very simple means enabling the caps to be reliably placed on the containers.

According to another feature of the invention, the said second path is internally tangent to the first path and its diameter is substantially equal to half the diameter of the said first path, the containers and the caps being displaced at one and the same linear speed along the said paths.

The provision of two internally tangential paths enables the overall dimensions of the machine to be reduced. Furthermore, the speed of the caps is reduced to zero with respect to that of the containers when they are located above the latter, and the caps can thus be placed on the containers more readily.

According to another feature of the invention, the said container-conveying means comprise a series of stools supported stationarily by a drum driven in rotation about a vertical axis and distributed uniformly at the periphery of the said drum, each stool being adapted to receive a container which rests upon it by its bottom.

According to still another feature of the invention, the said rotatable container-conveying means also comprise container-raising means associated with each stool and adapted to seize each container by its peripheral collar and raise it vertically above the said stool, so that the said collar, before receiving a cap, is located slightly below the plane of the path of the said cap, and then to apply the said container covered with the said cap against the said fixing means.

According to still another feature of the invention, the mechanical cap-conveying means comprise a transfer device receiving the caps delivered through a chute or the like and a rotatable member receiving the caps conveyed by the said transfer device and driving them along the said second circular path.

Still according to the invention, the said rotatable member comprises a series of fingers driven in rotation in synchronism with the said drum, each finger coming into contact with a cap supplied by the said transfer device and driving it in a circular guiding groove provided in a stationary plate or the like.

Other features and advantages of the invention will appear as the following description proceeds.

In the appended drawings given solely by way of example :

FIG. 1 is a top view of a machine according to a first form of embodiment of the invention ;

FIG. 2 is a sectional view upon the line II--II of FIG. 1 ;

FIG. 3 is a sectional view upon the line III--III of FIG. 2;

FIG. 4 is a developed view of the cam actuating the container-raising means and diagrammatically illustrates the operation of the machine ;

FIG. 5 is a perspective view of the plate provided with a circular guiding groove for the caps ;

FIG. 6 is a diagrammatic view of the machine drive system and the devices associated therewith ;

FIG. 7 is a partial sectional view upon the line VII--VII of FIG. 3 ;

FIG. 7a is a sectional view corresponding to that of FIG. 7, but relating to another form of embodiment of the cap-driving finger ;

FIG. 8 is a partial sectional view upon the line VIII--VIII of FIG. 3 ;

FIG. 8a is a view identical with that of FIG. 8, but relating to a modified form of embodiment of a cap and container guiding plate ;

FIG. 9 is a top view, including a partially sectional view upon the line IX--IX of FIG. 10, of the machine according to a second form of embodiment of the invention ;

FIG. 10 is a sectional view of the said machine upon the line X--X of FIG. 9 ;

FIG. 11 is a sectional view upon the line XI--XI of FIG. 9;

FIG. 12 is a partial view of the machine of FIGS. 9 to 11, showing a heating head and a cap-driving finger associated therewith, the said heating head being in its working lower position;

FIG. 13 is a view identical with that of FIG. 12 but showing the heating head in its idle upper position ;

FIG. 14 is a perspective view of the plate provided with a cap-guiding groove ;

FIG. 15 is a diagrammatic view of the retractable stop controlling the rotation of the heating-head drive-cam and the cap-detecting means associated therewith.

According to the form of embodiment illustrated in the drawings, more particularly in FIGS. 1 to 3, the machine comprises essentially a stationary frame 1 on which is secured a vertically extending cylindrical support 2. A hollow shaft 3 is rotatably mounted within the support 2, the said shaft being supported at the upper portion of the said support 2 through the medium of a thrust ball- or roller-bearing or the like 4. Wear-resistant rings such as 5a and 5b are provided between the shaft 3 and the support 2 to ensure the centring of the said shaft with respect to the said support. At the lower portion of the shaft 3 is keyed a drive pinion 7.

A cylindrical drum 8 is secured, through the medium of a radial web 9, to the upper portion of the hollow rotary shaft 3. The drum 8 is provided at its lower portion with a ring-shaped base 10 carrying twelve circular stools 12, each of which is adapted to receive one container. Each stool is secured to the base 10 through the medium of a vertical rod 13. The twelve stools 12 are arranged in one and the same horizontal plane and distributed uniformly on the base 10, their centres 12a being located on one and the same circle C1 concentric with the geometrical axis X--X' of the shaft 3 and shifted with respect to each other by 30.degree..

To each stool 12 is associated a container-raising device formed of a hollow circular-section cylinder 15, the diameter of which is substantially greater than that of the said stool, so as to be capable of receiving and containing the latter, each said cylinder being secured to a sleeve or the like 16 mounted slidingly on the rod 13 and provided with a roller 17 which runs on the upper side of a rail 18 having the general shape of a circular cylinder concentric with the drum 8 and secured to the frame by means of right-angled plates 19. The sleeve 16 and the rod 13 are provided with complementary splines in order to prevent the sleeve from rotating with respect to the rod. During the rotation of the drum 8, the cylinder 15 under the action of gravity is imparted a vertical ascending and descending motion determined by the profile of the rail 18, a developed view of which is shown in FIG. 4. The profile of the rail 18 comprises, in the direction of displacement of the rollers indicated by the arrow F1, a lower level run 18a corresponding to the incoming and outgoing of the containers, a first ascending portion 18b, an intermediate level run 18c, a second ascending portion 18d, an upper level run 18e and a descending portion 18f leading to the lower level run 18a.

The drum 8 is secured, through the medium of arms 20, to a support 21 in the shape of an annular crown on which are mounted 12 heat-sealing heads 22, each of which is arranged above a stool 12 in substantially coaxial relationship to the latter. Each heat-sealing head 22 is internally provided with an electric resistor, shown diagrammatically at 23, for the heating of a circular heating plate 24 located at its lower portion and so recessed as to receive a container provided with its cap. The resistor 23 is supplied through two leads 23 shown diagrammatically at 25a, 25b and connected respectively to two contact elements, for instance carbon brushes, 26a and 26b, solid with the drum 8, the said elements being in sliding contact with two rings, e.g., copper rings 27a, 27b, secured to the stationary support 2 through the medium of an insulating member 28. The rings 27a and 27b are themselves connected to a source of current, for instance direct current (not shown), by means of leads 29a and 29b.

The resistor 23 and the heating plate 24 of the heat-sealing head 22 are carried by a rod 30 mounted slidingly in a sleeve or the like 31 secured to the crown 21, so that they can slightly move vertically with respect to the said crown against the action of resilient means consisting of a stack of washers 32 in the shape of truncated cones.

Supply and delivery star-members of a known type, driven in rotation by the pinion 7 and shown diagrammatically at 35 and 36, supply the machine with containers to be closed and discharge from the machine the closed containers. The said star-members carry the containers on plates 37, 38 arranged in the plane of the stools 12.

The machine also comprises a cap-conveying device formed of a transfer device 40 and a rotatable member 50.

The transfer device 40 is formed of two helical springs 41A and 41B having one and the same pitch but inversed with respect to one another. The said springs are mounted on two identical parallel rods 42a and 42b which are incurved in the shape of quadrants of a circle and can rotate freely on themselves with respect to the said rods. The springs 41a and 41b, which are free at their lower ends, have their upper ends secured by means of screws 43a, 43b to rotatable rings 44a, 44b solid respectively with two pinions 45a, 45b meshing with one another. The springs 41a, 41b are therefore driven in rotation in opposite directions by the pinions 45a and 45b, themselves driven by a bevel gear 46 connected to a cap-cutting punch or machine of a known type shown diagrammatically at 70.

The rods 42a and 42b are provided with flats 47a and 47b so as to facilitate the engagement and displacement of the caps between the said rods. A guide bar 48, also in the shape of a quarter circle, is arranged in parallel relationship to and below the rods 42a and 42b, so as to guide the caps punched by the machine 70 and conveyed to the transfer device 40 through the medium of a chute 71 secured to the bar 48. A guide member 49 is also provided above the rods, for the purpose of guiding the caps by making them turn on themselves during their displacement along the transfer device 40 as will be explained below.

The rotatable cap-conveying member 50 is formed of a disk 51 provided with a series of arms 52 arranged radially and distributed uniformly with an angular spacing of 60.degree. about the said disk. Each arm is provided at its free end with a finger 53 and is hinged to the disk through the medium of a horizontal-axis hinge 54. The disk 51 is angularly adjustable by being mounted on a rotatable plate 55 which is itself supported by a table 56 secured to the upper portion of a stationary vertical shaft 57 supported at its lower portion by a seat or the like 58 solid with the frame 1. During the rotation of the plate 55, the fingers 53 move along a circle C2 which is internally tangent, at T, to the circle C1 and the diameter of which is substantially equal to half the diameter of the latter. The finger 53 serving to drive the caps are six in number, i.e., half the number of stools. The plate 55 is driven in rotation by a toothed gear comprising a first pinion 60 mounted rotatably on the stationary shaft 37 and solid in rotation with the drum 8 through the medium of a pin 61, an intermediate pinion 62 mounted rotatably on the table 56 and a pinion 63 solid with the plate 55. The ratio of the number of teeth of the pinion 60 to that of pinion 63 is 2/1, so that the fingers 53 perform two rotations of 360.degree. when the drum 8 and, therefore, the stools rotate only once through 360.degree..

A plate 75 for guiding the caps supplied by the transfer device 40 is secured to the table 56 through the medium of columns 76. The plate 75 is formed of an upper disk 77 (see FIG. 5) provided with a notch 78 allowing the caps to pass and of a lower disk 79 secured to the disk 77 and provided with a cap-guiding arcuate groove 80 concentric with the circle C2. An aperture 81 at the centre of the groove 80 allows the fingers 53 to pass, the said aperture being of course circular in shape and concentric with the circle C2.

A blade 85 mounted at the end of the plate 75 in proximity to the point of tangency between the circles C1 and C2 ensures the guiding of the containers and the caps, the said blade being provided with a horizontal-axis hinge 86 allowing for a slight vertical displacement of the blade.

A single motor 90 drives, through the medium of a reducer 91, the pinion 7 and, therefore, the rotatable drum 8 and the star-members 35 and 36 as well as the helical springs 41a and 41b, the latter being driven through the medium of the cutting punch 70 as shown diagrammatically in FIG. 6. In FIGS. 1 and 3 are shown the respective directions of rotation of the above-mentioned members and devices : F.sub.1 for drum 8, F.sub.3 and F.sub.4 for star-members 35 and 36, F.sub.5 and F.sub.6 for springs 41a and 41b. The drum 8 itself drives the fingers 53 along the path C1 in the direction of the arrow F.sub.2.

The cutting punch or machine 70 is designed to cut and deliver circular caps provided with a tongue L the number of caps thus provided corresponding to that of the containers. This means that the machine delivers twelve caps during one rotation of the drum 8 through 360.degree.. The caps guided by the chute 71 fall vertically between two turns of the springs 41a and 41b, their tongue L being directed upwardly so that the caps are retained on the transfer device 40, on the one hand, by the flats 47a, 47b of rods 42a and 42b and, on the other hand, by the lower guide bar 48. The helical springs 41a, 41b are driven in rotation on themselves in opposite directions, the caps 0 are driven in translation in the direction of the arrow F7 until they arrive in the notch 78 provided in the disk 77. During their displacement the caps are so turned by the guide member 49 that their tongues extend in one and the same direction when the caps arrive in the guide groove 80, as shown in FIG. 3. The caps with their tongues thus located at their front in the direction of translation in the groove 80 are then driven in the guide groove 80 of the disk 75 by the fingers 53 pushing them by their circular edge.

The containers R are supplied by the supply star-member 35 and are each placed on a stool 12. The roller 17 of the cylinder 15 associated with the stool receiving a container from the supply star-member 35 is then located on the lower level run 18a of the rail 18, so that the cylinder 15 is in its lower position. Thereafter, the roller moves along the ascending portion 18b of the rail, the clyinder 18 slides downwardly, meets the collar C of the container and raises the latter above the stool. This ascending motion of the cylinder 15 continues until the roller travels on the intermediate level run 18c. The collar of the container is then located slightly below the level of the guide groove 80, in proximity to the point of tangency T, and while the roller travels on the level run 18c a cap pushed by a finger 53 is brought above the container and placed on the collar of the latter as soon as it leaves the guide groove 80. Thereafter, the roller travels on the second ascending portion 18d, so that the cylinder 15 continues to raise the container provided with its cap until it meets the heat-sealing head 22. The heat-sealing operation takes place during all the time when the roller is on the upper level run 18e. Thereafter, the roller travels on the descending portion 18f and thus drives the cylinder 15 which moves the container back to the stool. The descending motion of the cylinder 15 continues until the roller reaches the lower level run 18a. During this descending motion of the cylinder the container is driven by the discharge star-member 36.

Obviously, the shape and dimensions of the stools and cylinders must be adapted to those of the containers. Thus, for instance, the inner diameter of the cylinder must be slightly greater than that of the container body and smaller than the maximum diameter of its collar.

Also, the cap-driving fingers 53 and the guide blade 85 may have a substantially rectilinear bearing face as shown in FIGS. 7 and 8 when the containers concerned are provided with plane collar C as in the case of the containers R shown in FIGS. 1 and 2. In the case of containers whose collar C is provided with a peripheral bead B into which the cap must be inserted, the said fingers and the said blade are advantageously provided at their lower portion with a step 53a and 85a as shown in FIGS. 7a and 8a, the said step comes into contact with the bead while the upper portion of the finger or of the blade comes into contact with the cap which is thus pushed and guided into the said bead.

It should be noted that owing to their being mounted hingedly the fingers 53 and the blade 85 are apt to follow the containers in their ascending motion after the cap is placed on them and before the heat-sealing operation is performed. This is highly useful where use is made of stepped fingers and blades which, owing to the said step, may be driven by the edge of the container.

A second form of embodiment of the machine will now be described, wherein the second circular path, that of the caps, comprises a first portion which is externally tangent to the first path, i.e., the path along which the containers move, and a second portion whose curvature is inverted with respect to that of the first portion and which is tangentially connected to the latter, the said second portion of the second path coinciding with the said first path.

It is thus understood that instead of moving along a path, the radius of which is equal to half the radius of the path of the containers, the caps, before being laid on the containers, move along a path which is exactly superposed to that of the containers, i.e. which has the same radius and is located slightly above the latter. Therefore, in contradistinction to the first form of embodiment wherein the superposition of the cap on the container occurs only at the point of tangency, each cover can be exactly superposed on the container at a relatively great distance and can therefore be placed on the container much more readily.

Moreover, in this second form of embodiment, each heating head mounted movably on its support can have two positions : a working position wherein the container and its cap, when raised by the cylinders, come into contact with the heating head so as to be welded together, and an idle position wherein this contact does not occur, actuating means controlled by cap-detecting means being provided to move the said head to one of the said positions or the other.

It is thus understood that in the absence of a cap, the heating head can be moved to its idle position, so that it cannot be in contact with a container without its cap and, therefore, it cannot be soiled or deteriorated by the contents of the said container.

In FIGS. 9 to 15 relating to the second form of embodiment of the machine according to the present invention, the same reference numerals are used to indicate the members which are identical with or equivalent to those of the first form of embodiment described above and illustrated in FIGS. 1 to 8. As in the first form of embodiment, the drum 8 carried by the rotatable hollow shaft 3 through the medium of the web 9 and the bearing 4 supports, on the one hand, the stools 12 and their associated cylinders 15 and, on the other hand, the annular support 21 of the heating heads 22 through the medium of arms 20' which, in contradistinction to arms 20 of the first form of embodiment, are straight instead of being bent and are placed internally with respect to the heating heads.

Instead of being placed in the central portion of the machine as in the first form of embodiment, the cap-conveying means are seen in FIG. 9 to be arranged on the right side of the machine. Such an arrangement offers the advantage of avoiding to concentrate in the central region of the machine the various cap-conveying members. It therefore facilitates the access to the machine and simplifies the supervising, maintenance and repair operations. The cap-supply means comprise essentially the transfer device 40, shown only partially since it is identical with the corresponding transfer device of the first form of embodiment, and a rotatable member indicated generally by the reference numeral 100, receiving the caps delivered by the transfer device 40, the said rotatable member being formed of a support consisting of a disk 101 provided with a series of radially extending arms 102, each of which is provided at its end with a finger 103 which moves along a circle C'2 tangent at T to the circle C1 of the centres of the stools 12. The disk 101 is angularly adjustable by being mounted on a shaft 104 arranged coaxially and secured to the shaft 105 mounted rotatably in a cylindrical support 106 secured to the frame 1 of the machine and provided at its lower portion with a drive pinion 107 which rotates in synchronism with the pinion 7 driving the drum 8. On the vertical shaft 105 is also mounted the discharge star-member 36 which first drives the containers on the plate 38 and then on a discharge conveyor 108.

A plate 110 for guiding the caps 0 supplied by the transfer device 40 is secured on the plates 37 and 38 through the medium of legs such as 111. The plate 110 is formed of a lower member 112 (FIG. 14) provided with a groove 113 formed of a first arcuate portion 113a concentric with the circle C'2 and a second arcuate portion 113b concentric with the circle C"2 which is equal to, but superposed on the circle C1, the said second portion 113b being connected tangentially at T to the portion 113a and ending at its opposite end with a notch 114 allowing the caps to pass. The plate 110 also comprises an upper member 115 provided, at its end located below the transfer device 40, with a notch 116 allowing the caps supplied by the said device to pass into the groove 113 of the lower member 112 and to be guided by the said notch together with the groove 113. The lower member 112 is provided at the centre of the groove 113a with an aperture 117 allowing the fingers 103 to pass, the said aperture being of course circular in shape and concentric with the circle C'2. Likewise, the upper member 115 is provided with an aperture 118 concentric with the circle C"2 and through which can pass drive-fingers 120 associated with each of the heating heads 22.

Each finger 120 is slidingly mounted in a tubular member or support 121 arranged rearwardly of each heating head (with respect to the direction of rotation F1) and secured through the medium of a right-angled or bent member 122 to the annular support 21 of the said heating heads. The fingers 120 extend obliquely to the vertical axis of the heating heads, their lower ends 120a being engaged in the aperture 118 of the upper member 115 of the plate 110 so as to drive the caps located in the groove 113. Each cylinder 15 is provided at its upper portion with an annular dog 124 which engages the lower end 120a of finger 120 so as to push it upwardly against the action of a return spring 123 when the said cylinder brings the container provided with its cap under the heating head 22.

The rod 30 of heating head 22 is slidingly mounted in an internal sleeve 130 provided at its upper portion with a cap or the like 131 and slidingly mounted in an outer sleeve 132 secured to the annular support 21. Pins 133 provided on the upper portion of the rod 30 and engaged in grooves 134 of the head 131 prevent the heating head from rotating. The heating head 22 and its rod 30 may be imparted a slight vertical sliding motion with respect to sleeve 130 against the action of a pre-stressed helical spring 135, whereas the sleeve 130 can move vertically with respect to sleeve 132 against the action of a helical spring 136 whose compression force is substantially less than that of spring 135. The vertical position of the sleeve 130 and, therefore, the heating head 22, with respect to support 21 is controlled by a cam 140 secured to a shaft 141 mounted rotatably on a support 142 solid with the annular support 21, the said cam being provided with two actuating arms 143, 144. The cam 140 is driven in rotation by two stop members, one of which, 145, is concealable or retractable and formed of or solid with the rod of a double-acting cylinder 146 mounted on a support in the form of a circular plate 147 solid with a hollow stationary shaft 148 (used instead of the shaft 57 of the first form of embodiment), and the other of which is a stationary stop member 149 which is also mounted on the plate 147. The stationary stop member 149 permanently engages the path of one arm 144, of the cam 140 so as to drive the said cam in rotation in the direction by which the heating head 22 occupies its working lower position (see FIG. 12), whereas the concealable or retractable stop member 145 may or may not engage (depending on whether it is in extended or retracted position) the other cam arm 143 so as to drive the cam in rotation in the direction by which the heating head 22 occupies its idle upper position (see FIG. 13). The position of the stop member 145 is controlled by a proximity detector 150 of a known magnetic-action type arranged on the cap-guiding plate 110, the said detector controlling the position of the retractable stop-member 145 through the medium of an amplifier 101 and an electromagnetic valve 152 connected to the double-acting cylinder 146 through conduits 153 passing in the hollow shaft 148. The electromagnetic valve 152 is provided to feed the double-acting cylinder 146 in such a direction as to move the stop member 145 into retracted position (shown in solid lines in FIG. 10), i.e., in a position where it does not meet the arm 143 of cam 140 every time the detector 140 detects the presence of a cap, or in the opposite direction to move the said stop member into extended position (shown in FIG. 10 in dotted lines) in case a cap is not present. The relative positions of the detector 150 and the retractable and stationary stop members 145 and 149 respectively are shown in FIG. 9 in dash-dotted lines.

The caps 0 supplied by the transfer device 140 and engaged into the groove 113 of plate 110 are first driven in the direction of arrow F4 by the fingers 103 of the rotatable device 100 along the first portion 113a of groove 113, and then by the fingers 120 along the second portion 113b of the said groove. Each of the containers R conveyed by the intake star-member 35 into the stools 12 is placed exactly below a cap, so that the latter is placed on the collar of the container as soon as it reaches the notch 114 and, therefore, leaves the guiding groove 113. The operation by which the container provided with its cap is raised by the cylinder 15 is performed as in the case of the first form of embodiment. During its ascending motion the annular dog 124 meets the finger 120 and pushes the latter against the action of the return spring 123 so as to prevent the application of the container against the head 22 from being hindered, the said head being assumed to be in its idle lower position. In the absence of a cap and, therefore, of an output signal from the proximity detector 150, the retractable stop member 145 is in the extended position shown in dash-dotted lines in FIG. 10. It thus meets the arm 143 which moves the cam 140 to the position shown in FIG. 13, so that the head driven by the return spring 136 moves to its idle higher position, i.e., a position higher than that which can be reached by the upper edge of the container and its cap. During the next rotation, the stationary stop member 146 moves the head to its working lower position.

The arrangements of the rotatable cap-driving member 100 in coaxial relationship to the discharge star-member 36 offers the advantage of simplifying the structure of the machine, but, obviously, such an arrangement is by no means compulsory and the member 100 may be distinct from the star-member 36, or it may be mounted in coaxial relationship to the intake star-member 35.

Of course, the invention is by no means limited to the forms of embodiment described and illustrated, which have been given by way of example only. In particular, it comprises all the means constituting technical equivalents to the means described as well as their combinations, should the latter be carried out according to the spirit of the invention.

Claims

What is claimed is :

1. Machine for sealingly closing containers each provided with an upper outwardly projecting collar, with a cap which is applied onto the said collar and then secured to the latter, comprising a frame structure, rotatable container-conveying means mounted on said frame structure and comprising a drum having a vertical axis and driven in rotation about said axis, rods and a series of stools distributed uniformly at the periphery of said drum, each one of said stools being supported on said drum by means of a said rod and being adapted to receive one of said containers, and to drive it continuously along a first circular path, a cutting punch for caps, a chute, mechanical cap-conveying means mounted on said frame structure and comprising a transfer device receiving the caps delivered by said cutting punch via said chute, a stationary plate having a circular guiding groove for receiving the caps conveyed by the said transfer device, the said guiding groove forming a second circular path and rotary driving means for driving said caps along the said second circular path, the latter path being tangent to said first path and being arranged above it so that a portion of said second circular path overlies said first circular path in the region of tangency, common motor means for driving said drum, said cutting punch, said transfer device and said rotary driving means in synchronism, whereby each cap travelling along said second path portion where it overlies said first path in the region of tangency is located above a container and moves by gravity and is deposited on the collar of each container, and fixing means adapted to secure on each container the cap deposited on its collar, said fixing means being arranged above said containers and being solid with said rotatable container-conveying means.

2. Machine according to claim 1 wherein said second path is internally tangent to said first path and its diameter is substantially equal to half the diameter of the first path, the said containers and the said caps moving at one and the same linear speed along the said paths.

3. Machine according to claim 1, wherein said rotatable container-conveying means also comprise means for raising said containers, said means being supported by said drum and being adapted to seize each container, associated with a stool and having received a cap, by its collar and raise it vertically, whereby said container and its associated cap are applied against said fixing means.

4. Machine according to claim 3, wherein said raising means comprise a hollow vertically sliding cylinder adapted to receive and contain the said stool and to meet, during its ascending motion, the collar of said container.

5. Machine according to claim 1, comprising a rail having the general shape of a circular cylinder concentric with said drum and wherein each one of said cylinders in solid with a sleeve mounted slidingly but not rotatably on said rod, each said sleeve being provided with a roller co-operating with said rail, so that the vertical motion of the said cylinder is controlled by the profile of said rail.

6. Machine according to claim 1, wherein said fixing means comprised of a series of heating heads mounted on a support solid with said rotatable drum, each heating head being arranged above one of said stools.

7. Machine according to claim 6, wherein said heating heads are mounted resiliently on the said support.

8. Machine according to claim 1, wherein said transfer device comprises two parallel arcuate rods, two helical springs placed respectively around said two parallel arcuate rods and said springs being driven in rotation in mutually opposite directions, so that each cap delivered through said chute engages between the turns of the said springs and is driven in translation along said rods.

9. Machine according to claim 8, wherein said transfer device includes a smooth guide-member for imparting a predetermined orientation to said caps.

10. Machine according to claim 1 wherein said rotary driving means comprises a rotatable member having a series of fingers driven in rotation in synchronism with said drum, each finger coming into contact with a cap supplied by said transfer device and driving it in said circular guiding groove.

11. Machine according to claim 1, further comprising a blade for guiding said containers and said caps, the said blade being arranged in proximity to said region of tangency of the paths of the said containers and the said caps, and being hingedly mounted on the said stationary plate so as to be capable of limited vertical displacement.

12. Machine according to claim 1 wherein said circular guiding groove in said stationary plate forms a second circular path comprising a first portion which is externally tangent to the said first path and a second portion, the curvature of which is inverted with respect to that of said first portion and which is tangentially connected to the latter, the said second portion of the second path coinciding with the said first path.

13. Machine according to claim 1 wherein said rotary driving means of said mechanical cap-conveying means comprise first rotatable means for receiving said caps conveyed by said transfer device and driving them along a first portion of said second circular path formed by said groove and second rotatable means receiving the caps driven by the said first rotatable means and driving them along the second portion of the said second path.

14. Machine according to claim 13, wherein said first rotatable means comprise a series of fingers mounted on a driven support, each finger coming into contact with a cap supplied by said transfer device and driving it along the first portion of the said groove.

15. Machine according to claim 13 wherein said second rotatable means comprise a series of rotating fingers, each finger of the said second rotatable means coming into contact with a cap supplied by one of the fingers of said first rotatable means and driving said cap along a second portion of the said groove.

16. Machine according to claim 15, wherein each finger of the said second rotatable means is associated with a fixing means so as to follow it when it is driven in rotation.

17. Machine according to claim 1 wherein said rotatable container-conveying means further comprises container-raising cylinders supported on said drum, movable fingers, return springs for said fingers and tubular supports and wherein each said finger of the rotatable means is slidingly mounted in a tubular support, said tubular support extending obliquely with respect to the said fixing means, its lower end engaging the path of said container-raising cylinders, so that during the ascending motion of the said cylinder the latter meets the said finger and pushes it upwardly against the action said return spring.

18. Machine according to claim 16, comprising a container-discharge star-member and wherein said support carrying the fingers of the said first rotatable means is arranged in coaxial relationship to said container-discharge star-member and is solid in rotation with the latter.

19. Machine according to claim 17, wherein said fixing means are formed of a series of heating heads each movably mounted on the said support so as to be moved to two positions, one, a working position in which said container and its cap come into contact with the said head, and a second, an idle position in which the said contact does not occur, actuating means controlled by cap-detecting means being provided to move the said heads to the required one of the said positions.

20. Machine according to claim 19, wherein each heating head is movable vertically with respect to the said support, the said actuating means comprising a return spring tending to push the heating head to said idle position, a rotary cam which, depending upon its angular position, acts or does not act upon the said heating head to move it to said working position against the action of the said spring, and means for driving the said cam in rotation, said cam driving means being controlled by the said detecting means.

21. Machine according to claim 20, wherein each one of said cams is provided with two arms, said cam driving means comprising a retractable stop-member having an extended position and a rectracted position and adapted, when in said extended position, to engage the path of one of the said arms so as to move said heating head to said idle position, and a stationary stop member engaging the path of the other arm so as to move said heating head to said working position.

22. Machine according to claim 21, wherein said retractable stop-member is associated with a double-acting cylinder controlled by the said detecting means.

23. Machine according to claim 22, wherein said detecting means comprise a magnetic-action detecting member, an amplifier, the said detecting member supplying, through the medium of said amplifier an electromagnetic valve for controlling said double-acting cylinder.