A capping machine

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DESCRIPTION

Capping machine.

Technical Field

The present invention relates to a capping machine, and, more precisely, to a machine for closing containers with screw lids or with snap closure lids in accordance with the preamble of claim 1 and as disclosed in the document EP 0.690.020.

Existing Technique

The existing technique includes capping machines that are composed of a carousel that rotates about a vertical axis and that comprises a drum that supports a plurality of capping units angularly equidistant around the periphery, each comprising a hollow shaft aligned on an axis. vertical, of which a bottom part incorporates a sliding bushing and is fixed to a capping head provided with a clamping mechanism.

Likewise, the carousel supports a disc arranged below the drum and coaxial with the latter, which has seats on which to arrange the containers vertically.

Each site receives a single container in correspondence of a feeding station. At the same time the corresponding capping unit receives a cover.

As the carousel rotates, between said feeding station and an exit station, the capping unit places the cap on the neck of the container and tightens it by screwing.

The capping unit, and consequently the hollow shaft, can carry out an axial movement, necessary to place the lid on the neck of the container, and a rotary movement, necessary to screw the lid onto the container.

Traditionally, the rotary movement of the individual capping unit is determined by a system of gears set in rotation by a central sprocket concentrically aligned with the axis of the carousel.

The axial movement of the capping unit, on the other hand, is determined by a cam follower roller fixed to said bottom part of the hollow shaft and linking the track that has a fixed drum-type cam, coaxial with the carousel, as per example what is described in documents uS 4.089.153, GB 1.245.081 and eP 0.690.020.

The lid is held and rotated on the container through a clamp, whose movements are mechanically induced, through means located inside the capping head and comprising springs calibrated in order to provide a firm hold of the lid.

Once the screwing stage is finished, the jaws of the clamps are separated by the action of cam means associated with the same clamp and in a position to overcome the resistance opposed by the springs.

In addition, each capping head is associated with a respective mechanical coupling clutch that serves to interrupt the transmission of the rotary movement to the capping head, once the cover has been screw-tightened and at the moment of opening the jaws of the pliers.

Capping machines of the type in question have some drawbacks.

Being driven with a rotary and an axial movement as described above, the hollow shafts in which the capping heads are located will tend to work under the forces of the tension springs of the pliers and of the cam follower rollers. In addition, hollow shafts are subjected to high levels of friction attributable to the use of sliding bushings.

Also, the individual capping units are relatively heavy and consequently during the rotation of the carousel they are subjected to considerable centrifugal and inertial forces.

These various factors dictate the need to use very strong materials and to adopt precision machining procedures, particularly for the cams, as well as to follow extremely precise and complex assembly procedures, to achieve and maintain correct axial alignment of each capping unit. with the axis of the respective underlying arranged container and ensure that this same axial alignment is periodically controlled.

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In addition to the above, the system by which the rotation is transmitted to each capping unit of the machines belonging to the known technique, which uses epicyclic trains, is extremely complex and expensive.

Disclosure of the Invention

The object of the present invention is to provide a capping unit that does not exhibit the disadvantages described above, apart from being inexpensive, efficient and easy to assemble.

Brief Description of Drawings

The invention will now be described in detail, by way of example, with reference to the attached drawings, in which:

figure 1 is a schematic and fragmentary plan view of the capping machine according to the present invention;

figure 2 is a detail of the machine of figure 1, shown schematically and in section, with some parts omitted;

figure 3 is an enlarged detail of figure 2, shown in section;

Figures 4, 5 and 6 show an enlarged detail of Figure 3 in three different operating conditions;

figure 7 is a detail of the machine of figure 1, illustrated schematically and in section, according to a second possible embodiment.

Detailed Description of the Preferred Executions of the Invention

With reference to figure 1, number 1 denotes a capping machine, in its entirety, used to close containers (2) by means of respective lids (3).

With reference also to Figures 2 and 5, each container (2) is configured with a neck (4) that has an external thread, in a position to be able to be coupled with the internal thread of a respective lid (3).

The capping machine (1) comprises a carousel (5) mounted so that it can rotate around a vertical axis (A), rotating clockwise as can be seen in figure 1. The carousel (5) is fed with a succession of containers (2) and with a different succession of lids (3), both received in correspondence of a feeding station (6) from a rotary conveyor (7).

The conveyor (7) rotates around an axis parallel to said vertical axis (A), rotating counterclockwise as can be seen in figure 1, and is positioned so as to receive a succession of containers (2) in correspondence of a first feeding station (8) coming from a horizontal channel (9).

Said conveyor (7), in addition, receives a succession of covers (3), in correspondence of a second feeding station (10), coming from a horizontal channel (11) that extends parallel to the previously mentioned channel (9).

The carousel (5) is suitable for assembling the lids (3) with the respective containers (2) and from there to advance the containers (2), each one provided with its lid (3), towards a second rotating conveyor (12) operative in correspondence of an exit station (13).

The second conveyor (12) can rotate around an axis parallel to said vertical axis (A), turning counterclockwise as can be seen in Figure 1, and serves to transfer the containers (2) already covered from the exit station ( 13) to a horizontal transfer conveyor (14).

As can be seen in figure 2, the carousel (5) comprises a frame (15) with a substantially horizontal upper wall (16) that presents a tubular projection (17) centered on the vertical axis (A), occupied by a fixed shaft (18) that passes through the same wall (16) and extends upward from the latter. To this same shaft (18) is installed with freedom of rotation by means of intercalated bearings (19) a tubular body, denoted with the number 20, which includes a lower circular flange (21) and an upper circular flange (22).

The lower flange (21) functions as a platform on which to arrange the containers (2) vertically and includes a disk (23), connected to its upper surface and centered on the vertical axis (A), which has a succession of seats peripherals (24) angularly equidistant from one another (see also figure 1).

The upper flange (22) is peripherally provided with a plurality of circular holes (25), each one of them aligned with a vertical axis (B) that coincides with a respective seat (24).

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The fixed shaft (18) is arranged with its upper end projecting above the upper flange (22) and is secured to a bottom wall (26) of the fixed cam drum (27) centered on the vertical axis (A), whose External cylindrical wall (28) has two annular grooves (29 and 30), upper and lower respectively.

The tubular body (20), the lower flange (21) and the upper flange (22) combine to create a central drum (31) installed with freedom of rotation to the fixed shaft (18) and put in rotation around the vertical axis ( A), rotating clockwise as can be discerned by looking at figure 2, by means of a motor (32) whose output shaft (33) extends through the upper wall (16) of the frame (15) and supports an interlocked pinion (34) that meshes with an internally rotating ring gear (35) integrally rotatable with the lower flange (21) and centered on the vertical axis (A).

As can be seen in Figures 2 to 6, each hole (25) houses a respective capping unit (36), provided with a capping head (37) comprising a clamp (38) with three jaws (39) angularly spaced, of of which only two can be seen in the attached drawings.

More precisely, each capping unit (36) is aligned with the respective axis (B), supported by the upper flange (22) in correspondence of a point that coincides with the respective circular hole (25) and, therefore, in conditions of rotate jointly with the drum (31) around the vertical axis (A).

Referring to Figure 3, each capping unit (36) is provided with axial guide means comprising an external tubular element (40) concentrically aligned with said axis (B), which presents an annular protrusion (41) in correspondence of a intermediate point along its length that rests on the upper flange (22) and is fixed to the same flange in the region of a corresponding hole (25), through threaded means (42).

The tubular member (40) houses a coaxially aligned tubular body (43) which can slide along the axis (B) of the capping unit.

The tubular body (43) is rigidly associated at its upper end with an appendix (44) arranged transversely with respect to the vertical axis (B), which links with freedom of sliding an axial groove (45) presented by the cylindrical wall of the tubular element (40).

At the free end of the appendix (44) a cam follower roller (46) is installed, positioned to interact with the upper groove (29) of the cam drum (27) when the central drum (31) is set in rotation, as way of moving the tubular body (43) axially relative to the tubular element (40).

Furthermore, with the tubular body (43) there is associated, diametrically opposite to the aforementioned appendix (44), a second appendix (47) arranged transversely to the vertical axis (B), which links a vertical groove (48) presented with freedom of sliding by the cylindrical wall of the tubular element (40).

The free end of the second appendix (47) is rigidly associated with a carriage (49) movable along the vertical axis of a pneumatic cylinder (50) fixed by means of wing nuts (51) to the cylindrical wall of the tubular element (40) .

Carriage (49) and pneumatic cylinder (50) provide support means associated with tubular body (43).

In particular with reference to Figures 3 and 4, number 52 denotes a transmission, in its entirety, housed coaxially within the tubular body (43) and rotatable about the vertical axis (B).

The transmission (52) comprises a first upper part (53), consisting of a rod (54) with longitudinal grooves (55).

The upper end of the slotted rod (54), which extends beyond the upper end of the tubular body (43), is connected to actuator means (56) by means of a coupling clutch (57) interconnected to a drive unit. master control 58, indicated schematically, in FIG. 3, as a block.

The coupling clutch (57) is arranged inside the tubular element (40), occupying a compartment (59) presented by the upper end of the same element (40).

The transmission (52) further comprises a second part (60) that takes the form of a tubular shaft grooved inside (61) put in rotation by the grooved rod (54) and, furthermore, free to slide axially with respect to the same rod.

The bottom end of the tubular shaft (61) is axially connected by means of the insertion of bearings (62) to the bottom end of the tubular body (43), and is closed by a substantially cylindrical body (63) supporting said capping head (37), as will be described in greater detail below.

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Said transmission (52) also comprises a shaft (64), aligned coaxially with the tubular shaft (61), whose bottom end passes through a hole (65) made in the cylindrical body (63) and is connected to articulated means controls, denoted in their entirety with the number 66, which serve to open and close the jaws (39) of the clamp (38).

Said shaft (64) functions as the rod of a piston (67) slidable inside a cylindrical chamber (68) presented by the bottom end of the tubular shaft (61) and delimited by an upper wall and a lower wall, denoted by 69 and 70 respectively in Figures 4, 5 and 6.

Furthermore, the space encircled between the lower wall (70) of the chamber (68) and the piston (67) is occupied by a compression spring (71) wound around the piston rod.

The upper end of the shaft (64) has a section (72) with a smaller diameter, creating a shoulder (73) that functions as a limit switch for a bushing (74), concentrically aligned on the vertical axis (B), within which it is possible to insert the shaft (64) with freedom of sliding.

The bushing (74) is fixed to the bottom end of a coupling (75), concentrically aligned with a tubular shaft and sheathing the latter, by means of a cross member (76) whose two ends project externally from the tubular shaft (61) through respective grooves (77).

Coupling (75) has internal grooves (78) that interconnect longitudinally with complementary external grooves (79) presented by tubular shaft (61).

In accordance with the above, the coupling (75) is set in rotation by the tubular shaft (61) being, at the same time, able to slide axially with respect to the same shaft.

The coupling (75) is also axially connected, by means of the insertion of a bearing (80), to the bottom end of a second tubular body (81), aligned with the vertical axis (B) and sandwiched between the first body tubular (43) and tubular shaft (61).

As can be seen in Figures 3 and 4, the upper end of the second tubular body (81) has an appendix (82) arranged transversely to the vertical axis (B), which passes through the groove (45) of the tubular element (40 ) and through a groove (83) presented by the first tubular body (43).

The appendix (82) supports a follower roller (84) that moves through said lower groove (30) of the cam drum (27).

In this way, when the upper flange (22) is set in rotation, the second tubular body (81), the coupling (75) and the piston (67) are forced by the cam drum (27) to move along vertical axis (B).

The part of said cylindrical chamber (68) arranged between the lower wall (70) and the piston (67) incorporates a door, provided with a hole (85) that passes transversely through the shaft (64), which forms part of a pneumatic circuit (86) comprising an axial conduit (87) extending through shaft (64), bushing (74) and slotted rod (54).

The circuit (86) in question receives compressed air from a source (88) schematized in Figure 3 as a block.

With reference to Figures 3, 4, 5 and 6, the capping head comprises a flared housing (89) with an upper tubular appendix (90) fixed to the internal part of said cylindrical body (63).

The housing (89) has three radial grooves (91), angularly equidistant from one another, which house the jaws (39) of the clamp (38). The clamp (38) of each head is supported by horizontal bolts (92) that pass through the respective jaws (39) in correspondence of an intermediate height.

The upper end of each jaw (39) is connected by means of respective coupling rods (93) to a block (94) rigidly associated with the bottom end of the shaft (64) and axially slidable within a cylindrical recess presented by said accommodation (89).

The block (94) and the coupling rods (93) provide said articulated means (66) by means of which the jaws (39) of the clamp (38) are opened and closed.

The bottom end of said block (94) has a restriction (95) aligned with the vertical axis (B), which is supported by the lid during the twisting stage of the lid placement sequence.

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The operation of the capping machine (1) will now be described, first referring to Figure 1, starting from a situation in which a container (2) and a corresponding lid (3) are driven by the rotary conveyor (7 ) on the carousel (5) in correspondence of the feeding station (6), located superimposed on each other, at an opportune moment so as to coincide with the passage of a capping unit (36).

The container (2) is transferred from the feeding station (6) to the platform presented by the lower flange (21), occupying a respective seat (24) of the disk (23).

The profile presented by the upper groove (29) of the cam drum (27) is configured such that when the container (2) and the respective lid (3) are admitted into the carousel (5), the capping head (37 ) gradually descends from an upper limit position of travel to a point where the restriction (95) comes into contact with the cover (3).

More precisely, the downward movement in question is induced by the cam drum (27), through the action of the cam follower roller (46), to the tubular body (43), to the tubular shaft (61), to the cylindrical body (63) and the housing (89).

The profile presented by the lower groove (30) of the cam drum (27), in turn, causes the simultaneous and gradual dragging of the three jaws (39) of the gripper (38) by the articulated control means (66) , together with said downward movement.

More precisely, the second tubular body (81) is forced by the cam follower roller (84) to slide axially relative to the first tubular body (43), inducing movement to the cross member (76) and the bushing (74) by means of said coupling (75).

The upward sliding movement of the bushing (74) allows the shaft of the piston rod (64) to move upwards by the action of the force imparted by the spring (71), thus pushing said block (94) upwards and causing that the jaws (39) are closed through the action of the coupling rods (93).

During this stage, in which the cover (3) is gripped, the actuating means (56) are kept detached from the grooved rod (54) by the action of the coupling clutch (57), commanded by the control unit (58 ) and, consequently, the rod (54) does not rotate.

While the carousel (5) rotates, the capping head (37) is gradually lowered by the interaction between the upper groove (29) of the cam drum (27) and the follower roller (46), to the point where the cover (3) is linked to the neck (4) of the container (2).

After which, the control unit (58) sends a command to the coupling clutch (57) to connect the slotted rod (54) and the actuating means (56), thereby obtaining that the jaws (39) of the clamp (38) is rotated around the vertical axis (B).

More precisely, the rotation is transmitted by the grooved rod (54), and the tubular shaft (61), both to the coupling (75) with the crossbar (76) and to the capping head (37).

During the stage in which the cover (3) is rotated on the neck, the compressed air source (88) is connected by the control unit (58) to the part of the chamber (68) between the lower wall (70 ) and the piston (67), by means of the pneumatic circuit (86), in order to induce another upward movement of the shaft (64) through the action of the piston (67), thereby increasing the clamping force on the jaws (39) of the caliper (38) and ensuring that the jaws are locked in the clamping position.

In the event that the covers (3) are not screwed on, but are pressed onto the container, the coupling clutch (57) will keep the actuating means (56) permanently uncoupled from the slotted rod (54), which, therefore, it will not rotate during any stage.

In another embodiment of the present invention, shown in Figure 7, the upper end of the means by which the axial movement is induced could incorporate a coupling (96), located inside the first tubular body (43) and slidable with respect to the latter.

Said appendices (44 and 47) are fixed to this same coupling (96) and can be introduced through respective vertical grooves (97 and 98) in the tubular body (43).

Said coupling (96), closed in its upper part by an annular cover (99), is surrounded by a helical compression spring (100), sandwiched between the annular cover (99) and the upper end of the underlying tubular body (43) .

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During operation, said coupling (96) is forced by the action of the cam follower roller (46) to move downwardly from an upper limit position, along the vertical axis (B).

As the appendix (47) is positioned against the lower edge of the respective groove (98), said coupling (96) begins to move the tubular body (43) downwards, and with it the capping head (37).

Once the lid (3) held between the jaws (39) of the clamp (38) has linked the neck (4) of the container (2), and during the subsequent stage in which the same lid (3) is turned On the neck, the tubular body (43) is free to move upward, moving against the action of the spring (100), which thus serves as a shock absorber, smoothing the movement of the capping head (37) during use.

It should be noted, from what has been described above, that a capping unit according to the present invention exhibits significant advantages over capping units belonging to the known art.

The conception of the tubular elements (40), which are an integral part of the structure of the carousel (5), is such that it is possible to make the placement of the individual capping units (36) simple and safe, eliminating any risk of misalignment. with the respective vertical axis (B) even during the rotation of the same carousel (5).

Furthermore, the capping head (37) has no internal gears and the coupling clutch mechanism is arranged above the individual capping unit, thus achieving a reduction in weight and consequently minimizing centrifugal and inertial forces.

In the execution just described, the actuating means (56) by which the capping head (37) is rotated around the vertical axis (B) are composed of an asynchronous electric motor, and the coupling clutch (57) is one of the kind of magnetic powder.

In the case that a very precise orientation of the lid is required, with respect to the container, for example a lid of non-circular or special geometry, then the actuating means (56) could take the form of a brushless motor connected to the units. individual cappers by means of a synchronization belt mechanism and interconnected to the master control unit (58), which will monitor and govern the torque, speed and position parameters of the same mechanism.