Device for controlling the movement of a movable element for a machine for manufacturing plastic receptacles

Abstract

A plastic container manufacturing machine, comprising a chassis having a camway with a cam and a countercam and an element which is movable relative to the chassis, bearing a roller interacting with the camway so as to ensure the displacement of the movable element, wherein the machine also comprises a device for controlling the displacement of the movable element, wherein the countercam has at least one portion which is movable relative to the chassis, and wherein the control device incorporates a distance sensor that continuously measures the distance of a movable portion of the countercam relative to a fixed reference point on the chassis.

Claims

1. A plastic container manufacturing machine, comprising: a chassis having a camway with a cam and a countercam; an element which is movable relative to the chassis, the element bearing a roller interacting with the camway so as to cause displacement of the movable element; and a device for controlling the displacement of the movable element, wherein the countercam has at least one portion which is movable relative to the chassis, the control device comprising a distance sensor that continuously measures the distance of the movable portion of the countercam relative to a fixed reference point on the chassis, and wherein the machine further comprises a computer unit coupled to the sensor, the computer unit being parametrized to identify, for each cycle of the machine, a variation in the displacement of the movable portion of the countercam relative to a predetermined displacement, to compare said variation to a range of predetermined authorized variations, and to generate a warning when said variation is outside of the range of authorized variations.

2. The manufacturing machine as claimed in claim 1, wherein the sensor is an inductive sensor.

3. The manufacturing machine as claimed in claim 2, wherein the movable portion of the countercam has an aperture, the sensor being fixed on the chassis and positioned inside the aperture.

4. The manufacturing machine as claimed in claim 2, wherein the sensor is integral with the movable portion of the countercam.

5. The manufacturing machine as claimed in claim 1, wherein the sensor is an optical sensor.

6. The manufacturing machine as claimed in claim 5, wherein the movable portion of the countercam has an aperture, the sensor being fixed on the chassis and positioned inside the aperture.

7. The manufacturing machine as claimed in claim 5, wherein the sensor is integral with the movable portion of the countercam.

8. The manufacturing machine as claimed in claim 1, wherein the movable portion of the countercam has an aperture, the sensor being fixed on the chassis and positioned inside the aperture.

9. The manufacturing machine as claimed in claim 1, wherein the sensor is integral with the movable portion of the countercam.

10. A method for detecting a risk of displacement failure of a portion of a countercam which is movable relative to a chassis of a container manufacturing machine as claimed in claim 1, wherein for each manufacturing cycle of the machine, the method comprises: generating a distance curve between the movable portion of the countercam and the fixed reference point on the chassis; identifying a deviation between the distance curve and a predetermined distance curve; comparing the deviation with a range of predetermined authorized variations; and generating a warning if the deviation is outside the range of authorized variations.

11. The method as claimed in claim 10, wherein identifying a deviation further comprises identifying a deviatory recurrence, throughout which the deviation of a respective one of the manufacturing cycles is compared with a deviation series from a previous one of the manufacturing cycles so as to detect an increasing drift of the deviation.

12. The method as claimed in claim 11, wherein the warning comprises a sound effect or a message transmitted to a production operator of the machine.

13. The method as claimed in one of claim 11, wherein the warning comprises an instruction to stop the manufacturing machine.

14. The method as claimed in claim 10, wherein the warning comprises a sound effect or a message transmitted to a production operator of the machine.

15. The method as claimed in one of claim 14, wherein the warning comprises an instruction to stop the manufacturing machine.

16. The method as claimed in one of claim 10, wherein the warning comprises an instruction to stop the manufacturing machine.

Description

(1) Other features and advantages of the invention will become more clearly apparent on reading the following description of preferential embodiments of the invention, which are given by way of illustrative and nonlimiting example, and the appended drawings in which:

(2) FIG. 1 is a detail view of part of a manufacturing machine according to the invention, according to a first embodiment;

(3) FIG. 2 is a detail view of part of a manufacturing machine according to the invention, according to a second embodiment;

(4) FIG. 3 is a control diagram of the displacement of a movable element of the manufacturing machine according to the invention, over multiple successive cycles in normal operating conditions;

(5) FIG. 4 is a control diagram of the displacement of a movable element of the manufacturing machine according to the invention, over multiple successive cycles in abnormal operating conditions.

(6) FIG. 1 schematically illustrates a plastic container manufacturing machine 1, according to the invention.

(7) Such a machine 1 comprises: a chassis 2; an element 3 which is movable relative to the chassis 2; a device 4 for controlling the displacement of the movable element 3; and a computer unit 5.

(8) With reference to FIGS. 1 and 2, the chassis 2 comprises a camway 6 having: a cam 61; a countercam 62.

(9) The camway 6 makes it possible to control the displacement of the movable element 3 as described below.

(10) For this, the movable element 3 bears a roller 7 which interacts with the camway 6.

(11) More specifically, the roller 7 comes into contact with the cam 61 and then, at the end of the camway 6, into contact with the countercam 62.

(12) In order to control the proper displacement of the movable element 3, the countercam has at least one portion 63 which is movable relative to the chassis 2.

(13) According to a first embodiment illustrated in FIG. 1, the movable portion 63 and the countercam 62 are in one piece. In other words, the countercam 62 is fully movable relative to the chassis 2 about a first pivot 8.

(14) According to a second embodiment illustrated in FIG. 2, the movable portion 63 is formed by one end of the countercam 62. A first part 62a of the countercam 62 is then fixed relative to the chassis 2, the movable portion 63 pivots relative to the first portion, and therefore relative to the chassis 2, about a second pivot 9.

(15) In this second embodiment, the movable portion 63 is held in a guiding position by return means 10 which have a tendency to push the movable portion 63 back into the continuation of the first part of the countercam 62. Return means may also be present for the first embodiment.

(16) Expressed differently, in the guiding position, the movable portion 63 has a guiding surface of the roller 7 that is tangent to a guiding surface of the first part of the countercam 62.

(17) The device 4 for controlling the displacement of the movable element 3 incorporates a distance sensor 11 that continuously measures the distance of the movable portion 63 of the countercam 62 relative to a fixed reference point on the chassis 2.

(18) According to a first embodiment, the sensor 11 is of the inductive type.

(19) According to a second embodiment, the sensor 11 is of the optical type.

(20) With reference to FIG. 1, which illustrates the first embodiment, the sensor 11 is integral with the movable portion 63 of the countercam 62.

(21) In the example illustrated with reference to FIG. 1, the sensor 11 is integral with the countercam 62, since the countercam 62 and the movable portion 63 are in one piece.

(22) The sensor 11 thus follows the movement of the countercam 62 and continuously measures the distance separating it from the chassis 2.

(23) In this instance, the reference point on the chassis 2 is then movable relative to the sensor since the rotational movement of the countercam 62 and the integrality of the sensor 11 on the countercam 62 bring about a circular displacement of the sensor 11.

(24) With reference to FIG. 2, which illustrates the second embodiment, the sensor 11 is integral with the chassis 2 and is housed in the movable portion 63 of the countercam 62.

(25) More specifically, the movable portion 63 of the countercam 62 has an aperture 621, the sensor 11 being fixed on the chassis 2 and positioned inside the aperture 621.

(26) In this instance, the reference point on the chassis 2 is then formed by the sensor 11 itself, which then continuously measures its distance relative to an edge of the aperture 621.

(27) During operation, when the roller 7 bears against and displaces the movable portion 63, the sensor 11 is spaced apart from a wall of the aperture 621 and records this distance continuously. When the roller 7 no longer exerts a force on the countercam 62, the movable portion 63 then returns to its initial position, that is to say in the continuation of the first part of the countercam 62.

(28) The computer unit 5 is coupled to the distance sensor 11, and is parametrized to identify, via a method described below, a deviation of the displacement of the movable element 3.

(29) More specifically, the computer unit 5 is parametrized to identify, for each cycle, a variation in the displacement of the movable portion 63 of the countercam 62 relative to a predetermined displacement, to compare said variation to a range of authorized variations, and to send a warning when said variation is outside of the range of authorized variations.

(30) The method is a method for detecting a risk of displacement failure of the movable element 3 relative to the chassis 2 of the container manufacturing machine 1.

(31) This method comprises, for each manufacturing cycle, the following steps: establishing a distance curve between the movable portion 63 of the countercam 62 and the fixed reference point on the chassis 2, as a function of time for example; identifying a deviation between the distance curve established and a predetermined distance curve; comparing the deviation with a range of acceptable variations; sending a warning if the deviation is outside the range of authorized variations.

(32) FIGS. 3 and 4 illustrate a series of distance curves between the movable portion 63 of the countercam 62 and the fixed reference point on the chassis 2.

(33) More specifically, FIGS. 3 and 4 illustrate the displacement D1, D2, D3, D4, D5 of five different movable elements 3 on one and the same camway 6.

(34) In FIG. 3, all of the displacements D1, D2, D3, D4, D5 are normal, that is to say that no deviation can be seen, and these curves form in particular the predetermined distance curves.

(35) By contrast, in FIG. 4, the displacements D2 and D3 have an anomaly.

(36) This is because, in comparison with the curves D2 and D3 of FIG. 3, the signal transmitted by the sensor 11 has significant variations, which is a sign of a deviation in the displacement of the movable elements 3.

(37) The computer unit 5 therefore must transmit this information to the production operators.

(38) For this, the machine 1 comprises a signaling system 12, comprising for example a screen, a loudspeaker and/or a light signal.

(39) When the computer unit 5 detects a deviation, it therefore controls the signaling system 12 in order to warn the production operators.

(40) To that end, the warning may consist in the transmission of a sound effect via the loudspeaker, if appropriate coupled to a light signal, or of a message to a production operator via the screen, for example.

(41) For enhanced precision, the method also comprises a step of identifying a deviatory recurrence, throughout which the deviation of the analyzed cycle is compared with a previous cycle deviation series so as to detect an increasing deviatory drift.

(42) This makes it possible in particular to verify that the anomaly or anomalies observed on the curves D1, D2, D3, D4, D5 are not isolated cases, for example as a result of the temporary presence of a defective container.

(43) In the event of significant deviation, for example, the warning consists in an instruction to stop the manufacturing machine 1.

(44) This makes it possible in particular to avoid any risk of irreversible damage to the manufacturing machine 1.

(45) By virtue of the production machine 1 and of the method which have been described, it is possible to monitor possible misalignment of the machine 1 and to proceed with predictive maintenance before significant breakage of the machine 1.

(46) In addition, the method makes it possible to monitor the development of the misalignment and possibly to identify a cause of the misalignment.