WO2016051224A1

WO2016051224A1 - Device for forming hollow bodies

Info

Publication number: WO2016051224A1
Application number: PCT/IB2014/002032
Authority: WO
Inventors: Jaume RIBAS CASOLIVE
Original assignee: Martinenghi, S.R.L.
Priority date: 2014-10-03
Filing date: 2014-10-03
Publication date: 2016-04-07

Abstract

Device for forming hollow bodies comprising: a frame (1) in which a work piece turntable (2) for the housing of hollow bodies (3) to be formed and a tool carrier plate (4) for housing the machining tools (5) are mounted coaxially; and a driving device. The turntable (2) is provided with a motor (6) for its indexed rotation and the machining tools (5) are mounted on the machining tool carrier plate (4) by respective linear actuators (7), operating individually and independently, providing a cyclic linear motion to said tools (5). The motor (6) and the linear actuators (7) are connected to a programmable automation controller (8).

Description

Title DEVICE FOR FORMING HOLLOW BODIES Object of the invention

The invention relates to a device for forming hollow cup shaped bodies, said device comprising: a machine frame, a turntable for holding the hollow bodies to be formed, a tool carrier plate for holding the machining tools and a driving device.

The turntable and the tool carrier plate are opposite each other, enabled to rotate one with respect to the other on the same axis of rotation and enabled to move linearly, in axial direction one with respect to the other.

The driving device comprises first driving means for providing a stepwise rotary movement and second driving means for providing a cyclic linear movement between the hollow bodies situated on the work piece turntable and the tools mounted on the tool carrier plate; enabling the formation of the hollow bodies by means of the machining tools in several successive machining steps.

Technical field of the invention This invention is applicable in the manufacture of containers and particularly in the formation of hollow cup shaped bodies, preferably of aluminium, to form an opening suitable for subsequent leak proof coupling of a lid or a dispensing nozzle on said hollow body. State of the art

From EP 0,275,369 A2 is known a shaping machine, with which hollow bodies of cup shaped metal, particularly aluminium, can be shaped, and particularly locally narrowed, to enable, for example, the coupling of a leak proof lid or a spray valve in the area of the opening.

The known shaping machine has a machine frame, in which a supporting tube is configured. On an outer surface of the supporting tube a work piece turntable is supported.

In a limited recess in the support tube a linearly movable guide tube is housed, on whose terminal region the tool carrier plate is installed.

A driving device is housed in the machine frame, which is configured to generate a movement of intermittent rotation of the work piece turntable and to generate an oscillating linear movement of the tool carrier. By the linear movement the tools provided in the tool carrier, in particular the forming tools, can be taken to tamp the hollow bodies contained on the circular work piece table, for machining the hollow bodies locally, in particular deforming them plastically. By intermittent rotational movement of the circular work piece table the hollow bodies can be taken in succession opposite to the tools installed on the tool carrier table, to obtain a step by step formation of the hollow bodies from an initial geometry to a final geometry. From DE 1777297 B2 a device for machining cylindrical metal containers is known, in which several work piece retainers are housed on a supported movable rotating carrier plate and can be deformed by tools which are fixed on another carrier plate which can perform a linear oscillating motion relative to the first carrier plate. In this rotational movement of the carrier plate there is provided a motor and a cog wheel gear, the carrier plate being secured after each step of rotation by means of a centring device.

The second carrier plate is installed in a hydraulic press that provides the desired linear movement.

From document EP 236 3215 a device for forming cup shaped hollow bodies with a machine frame, a driving device, a circular work piece table for holding hollow bodies and the tool carrier plate for housing the machining tools is known, in which the circular work piece table and the tool carrier plate are located opposite each other and are rotatable relative to each other on a rotational axis and linearly moveable relative to each other along the axis of rotation and wherein the driving device comprises a first driving means for providing step by step rotary motion and a second driving means for providing a cyclic linear motion between the circular work piece table and the tool carrier, to enable the formation of hollow bodies by means of the machining tools in several successive machining steps.

These devices are driven by a kinematic chain consisting of an electric motor, a primary transmission, a clutch-brake assembly, a secondary transmission, a crank and connecting rod mechanism and a main shaft that transmits the movement, and have the following disadvantages:

- The path of the tool holder plate is usually fixed. It can be made adjustable by the use of sophisticated mechanical and control systems, which substantially increase the cost of the device.

- The speed of deformation occurring in the advance of the tool carrier plate is linked to the return speed and the indexing speed of the carrier table carrying the hollow bodies, so that when it is necessary to reduce the deformation speed, the return and indexing speeds are also reduced with the consequent loss of production.

- The inertia of the entire kinematic assembly is very large, especially when the forming device has more workstations. In the event of a collision, reparations are huge and can cause the loss of device precision that is impossible to recover.

Description of the invention The device for forming hollow bodies, object of the invention, is of the type mentioned in the pre-characterizing part of claim 1 and has specific features aimed at solving the aforementioned problems. The object of the invention is to reduce the mechanical complexity of these types of forming devices and the high inertia of the kinematic assembly, and to eliminate certain production constraints set by the joint displacement at the same speed of all of the tools and the tool carrier plate in which they are mounted. To achieve these objectives, the invention proposes a device for forming hollow bodies with a different concept, which allows the elimination of the kinematic assembly which provides the tool carrier plate with a cyclical linear movement, and to independently control the movements of each of the working tools According to the invention: the turntable has a separate motor for its indexed rotation; the tool carrier plate mounted coaxially with the turntable is provided with means for positional adjustment in the axial direction relative to the axis and its fixing in a working position, so as to remain motionless during the process of formation of the hollow bodies; the tools are individually and independently mounted on the tool carrier plate by linear actuators, being connected the tools' linear actuators and the drive motor of the turntable to a programmable automation controller.

In a preferred embodiment, the linear actuators responsible for the individual driving of the respective tools, forcing them to describe cyclical linear movements, comprise a servomotor assembly and a ball screw.

With these features the movement of each of the tools may be individually programmed; both with regards to the length of its path, as well as to the speed and acceleration during forward and backward movement; optimizing the performance of the forming device. The device of the invention solves the aforementioned problems and provides clear advantages in both manufacture and use:

- The movements of each tool can be adjusted easily and accurately through the programmable automation controller or control unit, which ensures that the device works at the maximum speed allowed by the process.

- The indexing speeds of the turntable and the forward and reverse speeds of the tools can be adjusted individually.

- There is no mechanical limit for the path length of the tools.

- The risk of collision between moving parts of the device is eliminated, and the consequent strains and loss of precision involved in such collisions, since the programmable automation controller causes this to stop automatically in the case of detecting a tracking error from a predetermined value in any of the servomotors.

- A significant reduction in both the energy consumption and the size and weight of the forming device for hollow bodies.

Description of figures

To complement the description being given and for the purpose of facilitating the comprehension of the characteristics of the invention, this patent specification includes a set of drawings wherein, in an illustrative and unlimited way, the following is shown:

- Figure 1 shows a schematic view, sectioned along a vertical plane of an exemplary embodiment of the device for forming hollow bodies, according to the invention.

- Figure 2 shows an enlarged detail of a portion of Figure 1 in which an exemplary embodiment of one of the linear actuators used for the movement of the tools can be seen. Preferred embodiment of the invention

As seen in the exemplary embodiment shown in Figure 1 the forming device for hollow bodies comprises a frame (1) in which a work piece turntable (2) for housing hollow bodies (3) to be formed and a tool carrier plate (4) for housing machining tools (5) are mounted coaxially, the forming device comprises a driving device with first driving means (6) providing a step by step rotary motion, and second driving means (7) providing a cyclic linear movement between the hollow bodies (3) situated on the work piece turntable (2) and the machining tools (5) mounted on the tool carrier plate (4 ); enabling the formation of hollow bodies (3) by means of the machining tools in several successive machining steps.

The work piece turntable (2) is provided with a motor (6) forming the first driving means, for its indexed rotation so that in the successive turns of the turntable (2) the hollow bodies ( 3) arranged thereon come face to face with the successive machining tools (5) that are mounted on the machining tool carrier plate.

Unlike known forming devices, the tool carrier plate (4) mounted coaxially with the turntable (2) is provided with means (not shown) for its positional adjustment in the axial direction and its fixing in a working position so said tool carrier plate (4) remains immobile and unable to shift during the process of forming the hollow bodies (3). So that the tools (5) can act on the hollow bodies (3) performing their formation, the said tools (5) are mounted on the tool carrier plate (4) by respective linear actuators (7) operating individually and independently, conforming the second driving means of the forming device of the invention. The motor (6) responsible for providing an indexed rotation to the turntable (2) and the linear actuators (7) responsible for providing a cyclic linear motion to the machining tools (5) are connected to a programmable automation controller (8) . The programmable automation controller (8) can be individually programmed for the movement of each of the tools (5) concerning both the length of the path and the speed and acceleration during the forward and backward movements as well as the indexed rotation of the turntable (2) by the motor (6), providing the above mentioned advantages.

In the embodiment shown in the accompanying figures, and as can be seen in greater detail in Figure 2, each of the linear actuators (7) comprises a servomotor assembly (71 ) and a ball screw (72) to provide a cyclic linear motion to the corresponding machining (5) tool.

Once the nature of the invention as well as an example of preferred embodiment have been sufficiently described, it is stated for all pertinent purposes that the materials, form, size and arrangement of the elements described are susceptible to changes, provided these do not involve an alteration of the essential characteristics of the invention that are claimed subsequently.

Claims

1. - Device for forming hollow bodies; comprising: a frame (1) in which a work piece turntable (2) for housing hollow bodies (3) to be formed and a tool carrier plate (4) for housing machining tools (5) that are coaxially mounted; a driving device with first driving means providing a step by step rotary motion, and second driving means providing a cyclic linear movement between the hollow bodies (3) situated on the work piece turntable (2) and the machining tools (5) mounted on the tooi carrier plate (4) in order to form the hollow bodies (3) by means of the machining tools (5), in several successive machining steps; characterised in that:

- the work piece turntable (2) is provided with a motor (6) for its indexed rotation such that in the successive turns of the turntable (2) the hollow bodies (3) come face to face with the successive machining tools (5) that are mounted on the machining tool carrier plate;

- the machining tools (5) are mounted on the machining tool carrier plate (4) by respective linear actuators (7), operating individually and independently, providing a cyclic linear motion to said tools (5);

- the motor (6) and the linear actuators (7) are connected to a programmable automation controller (8).

2. -Forming device, according to claim 1 , characterised in that the tool carrier plate (4) is provided with means (not shown) for its positional adjustment in the axial direction and its fixing in a working position where it remains immobile and unable to shift during the process of forming the hollow bodies (3).

3. - Forming device according to any one of the preceding claims, characterized in that each of the linear actuators (7) comprises a servomotor assembly (71 ) and a ball screw (72) to provide a cyclic linear motion to the corresponding machining tool (5)·