DEVICE OF CONVOYING Of ENTITIES DISCRETES COMPRISING an ARM OF TRANSFERTPERFECTIONNE AND BLOWING PLANT OF CONTAINERS PROVIDED With SUCH a DEVICE

i

and Installation for blow moulding containers provided with such a

The invention relates to the field of systems for conveying discrete entities.

More particularly a device for conveying discrete entities comprises a carrier which is rotated continuously around an axis and which carries a transfer arm.

The transfer arm envisaged is of telescopic type and it comprises a radially inner portion attached to the support and a radially outer portion which can slide with respect to the inner radial portion according to an axis of elongation contained in a plane substantially perpendicular to the axis of rotation of the support. Extension of the arm is controlled by a cam system depending on the angular position of the arm about the axis of rotation of the support.

The arm has a grip head, which is capable of supporting at least one entity and which is rotatably mounted on the outer radial part of the arm about an axis of orientation substantially parallel to the axis of rotation of the support. The orientation of the gripper head is controlled by a cam system.

Are provided conveying devices of this type in machines for blow moulding containers in which the container is achieved by blowing by introducing into a blow mold a preform previously made by injection molding. The machines are used, for example, for the manufacture of bottles polyethylene terephthalate (PET). The preform has the form of a tube which is closed at one end and the other end of which already has the final shape of the neck of the container.

The preform is set within the mold after fed to a suitable temperature in a thermal conditioning. Once blown, each container is carried away from the mold to be directed to the output of the machine.

Many machines for blow moulding containers are of the rotating type. They then comprise a carousel that rotates continuously about its axis and which carries, at its periphery, a series of identical molds.

The conveying devices transfer arm, also known as transfer stars, are useful to a fed the preforms in the molds and, on the other hand, remove the vessels once formed, without having to stop the carousel. The transfer arms elongation variable avoid interference between the moulds and the conveyed objects.

In such transfer arms are also used to cause in the blow mould a body adapted to be at least partially overmolded with the material of the container. This is particularly the case of the handles attached to the containers in PET.

Furthermore, it is sometimes necessary that the conveyed object has finally a determined orientation. In a blowing machine, for example it may be a particular orientation of the preform which has undergone heating particular for the production of a vial flat, or of the precise positioning of the handle in the blow mold.

However, it is an application in which the orientation of the gripper head of the transfer arms is particularly important: the case of machines "bi-fingerprints" in which each blow mold has two cavities for simultaneously producing two containers. The transfer arms must then simultaneously supplying two preforms in the blow mold, each preform being received in one of the cavities. After the two containers formed, they are to be retrieved simultaneously by a transfer arm, the pick-up head comprises two pairs of gripper tongs.

For this purpose, it is known to provide transfer arms with gripping heads steerable as described above. There is this type of transfer arms on the machines " biempreinte " produced so far by the applicant. In these conveying devices, the elongation of the arm and the orientation of the gripper head are obtained by two cam systems which are independent of each other. Therefore, the outer radial part of the arm has a cam follower which cooperates with a cam path to control, alone, the elongation of the arm. The gripping head, which is hinged to the end of the radially outer portion, it also carries a cam follower which cooperates with another cam track to control, alone, the orientation of the head relative to the axis of elongation of the arm.

The device, although having been satisfactory, but nonetheless has certain limits as to the range of motion that it is possible to obtain. Furthermore, it requires specific providing means to maintain each of the two cam followers on the corresponding cam path.

The invention, therefore, to provide a novel design of these transfer arm which is independent of these limitations.

For this purpose, the invention provides a device of the kind previously described, characterized in that the elongation of the arm and the orientation of the gripper head are controlled by a single rocker arm which is articulated to the radially outer portion of the arm and which carries two cam followers each of which cooperates with a cam path independent.

In other features of the invention:

-the rocker and the gripping head coincide;

-the rocker and the gripper head are separate from each other, the rocker controlling the orientation of the head by means of a transmission device;

-the rocker and the gripping head are connected to each other via a link;

-the rocker and the gripping head are articulated on the outer radial part of the arm about two distinct axes;

conjugates-the cam grooves which control the elongation of the arm and the orientation of the head are each arranged according to a closed loop around the axis of rotation of the support; it is provided elastic return means tending to return the radially outer portion of the arm to a position of less elongation such that the two cam followers, which are arranged on the rocker on either side of a line parallel to the axis of elongation passing through the articulation axis of the rocker on the outer radial part of the arm, are pressed radially inwardly against the corresponding cam path;

-the elastic return means are interposed between the radially inner and outer portions of the arm;

-the device comprises at least two fixed plates superimposed each extend in a plane perpendicular to the axis of rotation of the support, the outer edge of each of the two plates forming one of the two cam tracks which control the elongation of the arm and the orientation of the head;

-the inner radial portion of the arm is mounted on the support to pivot relative thereto about a pivot axis substantially parallel to the axis of rotation of the support, and the pivoting of the arm relative to the support is controlled as a function of the angular position of the support about its axis;

-pivoting of the boom relative to the support is controlled by a cam system;

-the gripper head is simultaneously support two entities;

and

-the carrier has a plurality of identical transfer with adjustable head.

The invention also relates to an arrangement for organic thermoplastic material from preforms previously made by injection-molding, characterized in that it comprises at least one conveying device incorporating any one of the preceding claims.

Other features and advantages of the invention shall become apparent from the following detailed description and in the accompanying drawings in which:

-figure 1 is a schematic view and partial, perspective, of a conveying device according to the teachings of the invention;

and

-figures 2 and 3 are views of schematic plan view of two positions of the transfer arm shown in Figure 1, and which can be observed on the control of the elongation of the arm and of the orientation of the gripping head.

The Figure 1 a transfer arm 10 of a transfer star wheel 12 the type of that occurring in machines for the production of containers made of PET from blowing a preform, the preform being previously obtained by injection molding and then being heated beyond the glass transition temperature of the PET before being introduced in a blow mold.

The transfer wheel 12 can be used for conveying the preforms, at conveying of the containers, or the transport of handles to be reported to containers. It comprises first a support 14 which is embodied here in the form of a plate and which is rotated continuously about an axis AO which, for convenience, will be termed vertical. Support 14 The door thus one or more transfer arm 10.

Each transfer arm 10 extends substantially in a horizontal plane perpendicular to the axis A0, and comprises an internal radial portion 16 and a radially outer portion 18 which are integral with each other but which are slidable relative to each other according to an axis of elongation of the arm A1.

The radially inner portion 16 of the arm 10 is attached to the periphery of the support 14 tray-shaped so as to be pivotable about an axis A2 which is parallel to the axis A0 but not coincident therewith. Door The radially outer portion 16, at the end of a lever 20, a roller 22, which is intended to move within a groove 24 formed in a plate fixed control 26 substantially horizontal. The groove 24 extends in a closed loop around the axis A0, the radial distance of the path of the groove 24 with respect to the axis A0 varying with the angular position about said axis. The roller 22 is accommodated in the groove 24 so as to lie radially inwardly or outwardly against one of the two walls of the groove 24 for controlling the pivoting of the arm 10 in both directions about the axis A1.

Therefore, when the support 14 causes the arm 10 in rotation about the axis A0, the roller 22 moves along the fixing groove 24 and controls the pivoting of the arm 10 about the axis A2. This pivoting allowing accelerate or decelerate the movement of the free end of the arm with respect to the continuous rotation of the support 14.

Indeed, the free end of the radially outer portion 18 of the arm 10 carries a gripping head 28 which is rotatable about an axis A3 with respect to both parts 16, 18 of the arm 10. A3 The axis of orientation of the head is, for example, parallel to the axis A2 arm pivot 10. The head 28 has two gripping tongs 30 to be capable of grasping simultaneously two preforms 32 (or, at the output of the blow mold, two containers).

According to the invention, the elongation of the arm 10 and the orientation of the head 28 with respect to the axis of elongation of the arm 10 are controlled by a single rocker 34 which is articulated to the radially outer portion 18 of the arm 10 and which carries two cam followers 36, 38 each of which cooperates with a cam path independent 40, 42.

In the example illustrated, the rocker 34 is in the form of a piece independent of the head 28. Furthermore, while the independent parts could be hinged about a same axis, it has been selected in the example shown the articulation of the rocker 34 on the radially outer portion 18 of the arm 10 about an axis A4 which is parallel to the axis A3 but is distinct from it.

Furthermore, alternatively, may also be used the invention by providing that the cam followers 36, 38 are carried directly by the pick-up head 28, the rocker 34 and the gripping head 28 being then merged.

In the example shown, the cam followers 36, 38 are in the form of rollers mounted to rotate about their vertical axis at both ends of the rocker. The rocker is journalled on the arm 10 substantially at its center so that the two rollers 36, 38 are disposed on either side of the axis of elongation of the arm 10.

Furthermore, the two rollers 36, 38 are offset with respect to each other in the direction of the axis A3. Indeed, the two cam paths 40, 42 with which they are to cooperate are formed by the peripheral edge two fixed plates 26, 27 each extending one above the other in horizontal planes perpendicular to the axis A0. As in the example shown, may be provided that one 26 of the two plates is the same as that in which is formed the groove 24 controlling the pivoting of the arm 10. In all cases, the cam grooves thus form a closed circuit around the axis A0, the distance from axis varies as a function of the angular position around the axis A0.

As shown in Figures, elastic return means 44 tend to return the arm 10 to a position of less elongation, i.e. to return the radially outer portion 18 of the arm 10 radially inwardly in the direction of the axis A2. These elastic return means 44 are for example made in the form of one or more tension spring, the two ends of which are hooked respectively on the inner and outer radial portions 16 18 of the arm 10.

By rotating the outer radial part 18 of the arm 10 inwardly, the elastic return means 44 press each of the two cam followers 36, 38 on the cam track 40, 42 corresponding. Because the two rollers 36, 38 are distributed on either side of the point of articulation of the rocker 34, first move around the axis A4 depending on the distance of the two respective radial contact points of the cam paths 40, 42 with respect to the axis A0. For a given position, the two rollers being supported on their cam track, the rocker 34 is blocked radially inward so that the elongation of the arm 10 is attached.

In the example illustrated, the rocker 34 being a separate part of the gripping head 28, the two parts are to be connected by a transmission mechanism so that the orientation of the rocker about the axis A4 controls the orientation of the head 18 about the axis A3.

Therefore, it is possible for example to predict connecting these two parts by a link 46 which is hingedly joined at its two ends on the one hand on the rocker 34 and on the other hand on the head 28. Of course, the points of articulation of the link rod are arranged neither with the A4 of articulation of the rocker 34 neither with the A3 of orientation of the head 28. Depending on the position of these coupling points, can be vary the gear ratio between the angular movement of the rocker 34 and that of the head 28.

As, from the comparison of the Figures 2 and 3, when the carrier 14 rotates about the axis A0, the arm 10 is driven generally of a motion that is the composition of two rotations about the axes A0 and A2, and, according to the movement of said compound, the rocker is caused to move along the cam paths 40, 42 to control the elongation of the arm 10 and the orientation of the head 28.

The conveyance device according to the invention is simple and reliable, and it can keep high amplitude for the swivelling motion of the gripping head 28. This movement also can be made with relatively large speeds by obtaining a wide variation of the orientation of the head 28 for a low overall movement of the arm 10.

Furthermore, we can see that, in this device, the same elastic return means which maintain the contact of the two cam followers 36, 38 on their respective cam paths 40, 42.