Device for the dimensional inspection of containers having contact optical detection

Abstract

An inspection device comprises movable equipment driven relative to a frame and provided with external and internal inspection gauges. Detection systems are provided for detecting contacts occurring between the internal and external gauges and a container. Each detection system further comprises an emitter and receiver system for emitting and receiving a light beam in a direction parallel to the travel direction of the movable equipment. A movement transformation mechanism carried by the movable equipment is also provided for transforming the travel movement of the gauge relative to the movable equipment into a movement that obstructs or ceases to obstruct the light beam.

Claims

1. An inspection device for inspecting the rings and the necks of containers (2), the device comprising: movable equipment (6) driven relative to a frame (7) with reciprocating motion along a travel direction parallel to the axis of symmetry of the containers and with a maximum stroke, the movable equipment being provided with an external gauge (14) for inspecting the outsides of the rings of containers and with an internal gauge (15) for inspecting the insides of the rings and of the necks of containers, the external and internal gauges (14, 15) being mounted to be movable independently of each other and relative to the movable equipment (6) in a travel direction parallel to the travel direction of the movable equipment; a measurement system (30) for measuring the position of the movable equipment (6) relative to the frame, in the travel direction, the measurements of the position of the movable equipment being supplied to a processor unit (31); a detection system (35) for detecting contact occurring between the internal gauge (15) and the container (2) during movement of the movable equipment (6), occurrences of contact being supplied to the processor unit (31); a detection system (37) for detecting contact occurring between the external gauge (14) and the container (2) during movement of the movable equipment, occurrences of contact being supplied to the processor unit (31); and a processor unit (31) acting as a function of the measurements of the position of the movable equipment (6) and of occurrences of contact between the gauges (14, 15) and the container (2) to determine whether the rings and/or the necks of the containers have dimensions that are in compliance and to determine the types of defect for containers that are dimensionally not in compliance; the device being characterized in that each detection system (35, 37) for detecting contact with a gauge comprises: an emitter and receiver system (70) for emitting and receiving a light beam (71) in a direction parallel to the travel direction of the movable equipment and over a segment of length that is not less than the maximum stroke of the movable equipment (6), the emitter and receiver system being carried by the frame; and a movement transformation mechanism (72, 73) carried by the movable equipment (6), for transforming the travel movement of the gauge (14, 15) relative to the movable equipment (6) into a movement that obstructs or ceases to obstruct the light beam (71) in order to detect the occurrence of contact with the gauge regardless of the position of the movable equipment (6).

2. A device according to claim 1, characterized in that the movement transformation mechanism (72, 73) transforms the linear travel movement of the gauge (14, 15) into pivoting movement of a target (74) in a plane containing the light beam.

3. A device according to claim 2, characterized in that the movement transformation mechanism (72, 73) includes a scissors mechanism (75) hinged and mounted between the movable equipment (6) and the gauge (14, 15).

4. A device according to claim 1, characterized in that the movement transformation mechanism (72, 73) transforms the linear travel movement of the gauge into rotary movement in a plane perpendicular to the direction of the light beam.

5. A device according to claim 4, characterized in that the movement transformation mechanism (72, 73) includes a helical connection (81) associated with a planar linkage (82).

6. A device according to claim 1, characterized in that the emitter and receiver system (70) for emitting and receiving the light beam comprises an emitter (E) and a receiver (R) for a light beam (71) that are mounted facing each other and that are spaced apart from each other by at least the maximum stroke of the movable equipment (6).

7. A device according to claim 1, characterized in that the emitter and receiver system (70) for emitting and receiving the light beam comprise an emitter (E) and a receiver (R) of the light beam that are mounted together with an optical reflector (R.sub.1) being mounted opposite them.

Description

(1) Various other characteristics appear from the following description given with reference to the accompanying drawings which show embodiments of the invention as non-limiting examples.

(2) FIG. 1 is a diagrammatic elevation view in section of the inspection device in accordance with the invention in its high position relative to a container.

(3) FIG. 2 is a diagrammatic elevation view in section of the inspection device in accordance with the invention in its position for inspecting a container.

(4) FIG. 3 is a diagrammatic elevation view in section showing a variant embodiment of the light beam emitter and receiver system.

(5) FIG. 4 is a diagrammatic elevation view in section showing another embodiment of a motion transformation mechanism forming part of the detection system in accordance with the invention.

(6) FIGS. 5A through 5H are elevation views in sections showing various configurations of the inspection device corresponding respectively to: inspecting a defective ring diameter corresponding to a ring that is too large; correct bore and correct ring diameter; inspecting a defective ring diameter corresponding to a ring that is too small; defective bore corresponding to a bore that is too small; defective bore corresponding to a bore that is too great; defective bore corresponding to a choke neck bore; extracting the tooling; and detection corresponding to no container.

(7) As can be seen more clearly in FIG. 1, the subject matter of the invention relates to an inspection device 1 enabling hollow containers 2 to be inspected at a high rate, which containers may be of any suitable kind, e.g. being made of glass and presenting an axis of symmetry X. In conventional manner, each container 2 presents a neck 3 having a ring 4 defining the inside of an opening 5 giving access to the inside of the container 2. More precisely, the inspection device 1 serves to inspect the neck 3 and the ring 4 of a container 2 in order to determine that the rings and the necks of containers have compliant dimensions, and in order to determine the types of defect for containers of non-compliant dimensions.

(8) The inspection device 1 is for fitting to any container production machine in which containers are delivered into register with the inspection device 1 at a high rate by using any appropriate means. The production machine and the means for bringing containers to the inspection device 1 and the means for handling containers are not described since they are well known to the person skilled in the art and they do not specifically form part of the subject matter of the invention. The inspection device 1 is mounted on the structure of an inspection machine that is incorporated in or added to the production machine. In the example shown, it is should be observed that the containers 2 are brought into register with the inspection system 1 in an upright or vertical position such that the axis X of symmetry of a bottle can be considered as extending in a vertical direction.

(9) The inspection device 1 includes equipment 6 that is movable relative to a support frame 7. The movable equipment 6 is driven by a motor system 9 for imparting reciprocating motion to the movable equipment in a travel direction parallel to the axis of symmetry X of the containers 2. In the example shown, the movable equipment 6 thus presents, in association with each container 2, a downward movement and an upward movement in a travel direction that is vertical since the bottle 2 occupies an upright position while it is being inspected by the device 1 of the invention. Naturally, the device 1 is suitable for inspecting bottles placed in various positions.

(10) According to a preferred embodiment characteristic, the motor system 9 comprises a servo-motor 10 having its body secured to the support frame 7. The servo-motor 10 has an outlet pinion 11 co-operating with a rack 12 forming part of the movable equipment 6. The servo-motor is controlled to drive its outlet pinion 11 in rotation in one direction and in the opposite direction in order to impart downward and upward motion cyclically to the rack 12 along the vertical axis.

(11) The movable equipment 6 includes an external gauge for inspecting the outsides of the rings 4 of containers, and an internal gauge 15 for inspecting the insides of the rings and the necks of containers 2. As explained in the description below, the gauges 14 and 15 are driven in reciprocating motion by the movable equipment 6 in order to come into contact with a container 2 during the downward movement of the movable equipment 6.

(12) More precisely, the gauges 14 and 15 are mounted concentrically and they possess a common axis of symmetry S extending in a vertical direction so that in an inspection position, the axis of symmetry X of the container 2 and the axis of symmetry S are in alignment. On each downward movement of the movable equipment 6 along the vertical axis X, the gauges 14 and 15 inspect the dimensions of the ring and of the neck of the container that is present. Advantage is taken of the upward movement of the movable equipment to remove the inspected container and to bring into place the next container for inspection.

(13) The external gauge 14 is in the form of a bell of annular shape centered on the axis of symmetry S. The external gauge 14 presents a bottom end referred to as an introduction end 16 defining a calibration opening or bore 17. The inside diameter of the calibration opening 17 is equal to the greatest acceptable diameter for the ring 14 of a container. Thus, as shown in FIG. 5A, if the ring 4 of the container presents a diameter greater than the diameter of the calibration opening 17 (ring too large), then the ring 4 of the container comes into abutment against the bottom end 16 of the external gauge 14.

(14) The calibration opening 17 is defined by an inside shoulder 18 for coming into contact against or pressing against the mouth or rim 4.sub.1 of the ring 4.

(15) In a preferred embodiment, the external gauge 14 also has an escape opening or bore 19 arranged beyond the shoulder 18 and communicating with the calibration opening 17 and opening out at the second end 20 of the external gauge opposite from its bottom first end 16. This escape opening 19 is provided with a stop shoulder 21 situated between the second end 20 and the shoulder 18.

(16) Thus, the calibration opening 17 and the escape opening 19 define between them the annular shoulder 18, which is of width that corresponds to the tolerance range for the width of compliance rings 4 (FIG. 5B). In other words, under all circumstances in which the ring 4 presents a compliant diameter, the external gauge 14 comes to bear via its shoulder 18 against the rim 4.sub.1 of the ring 4. When the ring 4 presents a diameter that is less than the diameter of the escape opening 19 (FIG. 5C), then the escape opening 19 of the external gauge 14 receives the ring 4 which then comes into contact with the external gauge 14 either via the bottom end 16 or else via the stop shoulder 21.

(17) The internal gauge 15 is in the form of a pin or plunger mounted inside the external gauge 14 in concentric manner relative to the external gauge 14. The gauge 15 is symmetrical in shape centered on the axis of symmetry S, and it defines a bottom segment 24 that is separated by a shoulder 25 from a top segment 26. The diameter of the top segment 25 is greater than the diameter presented by the bottom segment 24. The diameter of the bottom segment 24 presents a diameter corresponding to the minimum diameter that can be accepted for the mouth of the container 2, while the diameter of the top segment 26 corresponds to the maximum diameter that can be accepted for the mouth of the container. Thus, the annular shoulder 25 that is defined between the top and bottom segments 26 and 24 presents a width that corresponds to the tolerance range for the inside diameter of the neck of the container. When the neck 3 presents a diameter that lies within the tolerance range, then the internal gauge 15 comes into abutment via its shoulder 25 against the rim 4.sub.1 of the ring (FIG. 5B).

(18) In a preferred embodiment, starting from the bottom segment 24, and the internal gauge 15 also presents, an end segment 27 of diameter that is less than the diameter of the bottom segment 24. The end segment 27, which possesses a free or abutment end 28, is connected to the bottom segment 24 by a connection collar 27.sub.1.

(19) When the neck 3 of the container 2 presents a diameter that is too small, then the pin comes into abutment via its end segment 27 and in particular via its connection collar 27.sub.1 against the container 2 (FIG. 5D). If the inside diameter of the neck 3 is greater than the maximum diameter of the tolerance range, then the top segment 26 penetrates inside the neck 3 of the container (FIG. 5E). Furthermore, when the neck of the container presents a bore defect (FIG. 5F), the internal gauge 15 comes into abutment via the rim of the ring against the end segment 27.

(20) According to a preferred embodiment characteristic, an extractor tube 29 is interposed between the external gauge 14 and the internal gauge 15. This extractor tube 29 has a first end 29.sub.1 fastened to the frame 7 so that its longitudinal axis of symmetry coincides with the axis of symmetry S. The extractor tube 29 has a second end 29.sub.2 opposite from the first end 29.sub.1 and extending between the internal gauge 15 and the external gauge 14. In other words, the external gauge 14 extends outside the extractor tube 29 while the internal gauge 15 extends inside the extractor tube 29.

(21) The diameter of the extractor tube 29 is selected to enable it to come into contact with the rim 4.sub.1 of the ring 4 in the event of the container rising with the movable equipment 6 so as to disengage the container from the movable equipment 6 (FIG. 5G).

(22) It should be observed that the external gauge 14 and the internal gauge 15 detect each defect at a given position in their movement along the vertical axis that differs from one defect to another. Thus, by way of example, the internal gauge 15 occupies a greater altitude on detecting a choked neck (FIG. 5F) than the altitude it occupies when the internal gauge 15 detects a neck of correct dimensions (FIG. 5B). Likewise, the external gauge 14, on detecting a ring diameter that is too great (FIG. 5A), occupies a position that is at an altitude greater than the position occupied by said external gauge 14 on detecting a ring diameter that is too small (FIG. 5C).

(23) The inspection device 1 also has a system 30 for measuring the position of the movable equipment 6 relative to the frame in the travel direction of the movable equipment. The system 30 may be implemented by any means enabling the position of the movable equipment along the travel axis to be known. In a preferred variant embodiment, the measurement system 30 comprises a position sensor forming part of the servo-motor 11. Such a measurement system 30 thus enables the position of the movable equipment 6 relative to the frame 7 to be known and consequently enables the position of the internal and external gauges 15 and 14 to be known, in the vertical direction in the example shown. In other words, such a measurement system 30 serves to give an abscissa position for the movable equipment 6 relative to an origin along a distance measurement scale extending along the vertical axis.

(24) The measurement system 30 is connected to a processor unit 31 of any known type, e.g. in the form of a microcomputer. The measurement system 30 thus provides the processor unit 31 with measurements of the position of the movable equipment 6. Insofar as the positions of the gauges 14 and 15 relative to the movable equipment 6 are known, the processor unit 31 knows the positions of the gauges 14, 15 relative to the stationary frame.

(25) The inspection system 1 also has a contact detection system 35 for detecting contact between the internal gauge 15 and the container 2 during movement of the movable equipment 6. This detection system 35 is connected to the processor unit 31. The processor unit 31 is thus capable of detecting contact occurring between the internal gauge 15 and the container 2.

(26) The inspection system 1 also has a contact detection system 37 for detecting contact between the external gauge 14 and the container 2 during movement of the movable equipment 6. This detection system 37 is connected to the processor unit 31. The processor unit 31 is thus capable of detecting contacts occurring between the external gauge 14 and the container 2.

(27) Furthermore, the external gauge 14 and the internal gauge 15 are mounted to be movable along the travel direction independently of each other and relative to the movable equipment 6. In other words, it must be understood that each gauge 14, 15 is capable of moving individually along the vertical travel direction in the event of the gauge coming into contact with the container 2.

(28) In advantageous manner, the inspection device 1 includes an internal damper mechanism 40 for damping contact between the container 2 and the internal gauge 15 and for returning said internal gauge into position. The inspection device 1 also has an external damper mechanism 41 for damping contact between the container 2 and the external gauge 14 and for returning the external gauge to position. Each damper and return mechanism 40, 41 is thus suitable firstly for damping contact when it occurs between a gauge 14, 15 and the container 2, and secondly for returning each gauge 14, 15 into its initial or rest position in the absence of contact with the container 2.

(29) As can be seen more precisely in FIG. 1, the external gauge 14 and the internal gauge 15 are mounted to be movable along the travel direction relative to a support 45 for the movable equipment 6. This support 45, which is naturally movable relative to the stationary frame 7, includes the rack 12 having its bottom end secured to a part 46 for holding and guiding the external gauge 14. This guide part 46 in the example shown is in the form of a plate having a through hole 47 for passing the extractor tube 29, thereby allowing the plate 46 to perform vertical sliding movement relative to the stationary extractor tube 29. The top end of the rack 12 is securely mounted by a connection part 48 to a guide jacket 49 extending substantially parallel to the rack 12. This jacket 49 is guided to move in vertical sliding relative to the frame 7 by guide members 50 of any known type. The jacket 49 is mounted so as to extend at least in part inside the extractor tube 29.

(30) The support 45 is thus formed by the rack 12, the connection part 48, the jacket 49, and the plate 46. The external gauge 14 and the internal gauge 15 are mounted to move independently of each other relative to the support 45 and with the help of respective ones of the damping and return mechanisms 41 and 40.

(31) Thus, by means of the damping and return mechanism 41, the external gauge 14 is provided with at least one, and in the example shown three, guide shafts 52 that are movably mounted relative to the plate 46. Each shaft 52 is provided with a return spring 53 interposed between the external gauge 14 and the plate 46 in order to return the external gauge 14 into its rest position.

(32) In the absence of contact between the external gauge 14 and the ring 4 of a container, the external gauge 14 occupies a rest position relative to the support 45, which position is determined by the return springs 53 and by an abutment carried by the shafts 52 and coming to bear against the plate 46 (FIG. 1). During contact between the external gauge 14 and the ring 4, the external gauge 14 is subjected to a force causing the external gauge 14 to rise relative to the support 45, thereby compressing the return springs 53 (FIG. 2). While the movable equipment 6 is moving upwards, the thrust of the ring 4 against the external gauge 14 disappears so that the return springs 53 cause the external gauge 14 to return to its initial rest position.

(33) The damping and return mechanism 40 has a rod 60 presenting a bottom first end that is secured to the internal gauge 15. This rod 60 is mounted inside the jacket 49, which makes use of any appropriate guide means 61 to guide the rod 60 in sliding relative to the jacket 49.

(34) Between the internal gauge 15 and the bottom end of the jacket 49, the rod 60 advantageously includes a spring 63. In the absence of contact between the internal gauge 15 and the container 2, the spring 63 acts on the internal gauge 15 so that it occupies a rest position relative to the guide jacket 49. The rod 60 is held in this position by means of an abutment carried by the rod and coming to bear against the jacket 49 (FIG. 1). In the event of the internal gauge 15 coming to bear against the ring 4, the internal gauge 15 is subjected to a force causing the rod 60 to move upwards relative to the guide jacket 49 (FIG. 2). In the event of thrust between the gauge 15 and the ring 4 coming to an end, the spring 63 tends to return the internal gauge 15 to its initial rest position.

(35) In accordance with the invention, each detection system 35, 37 for detecting contact between a gauge 15, 14 and the container 2 includes an emitter and receiver system 50 for transmitting and receiving a light beam 71 in a direction parallel to the travel direction of the movable equipment 6. According to a characteristic of the invention, the emitter and receiver systems 70 are mounted on the frame 7 in stationary manner. Each light beam 71 is created along a segment of length that is not less than the maximum stroke of the movable equipment 6 so as to make it possible, as explained in the description below, to detect the occurrence of contact anywhere along the stroke of the movable equipment 6.

(36) Each detection system 35, 37 for detecting contact against a gauge includes a respective transformation mechanism 72, 73 for transforming the travel movement of a gauge 15, 14 relative to the movable equipment 6 into a movement that obstructs or ceases to obstruct the light beam 71 in order to detect contact occurring with the gauge, regardless of the position of the movable equipment 6. Each transformation mechanism 72, 73 is carried or supported by the movable equipment 6.

(37) In a variant embodiment shown in the drawings, in the absence of relative movement between the movable equipment 6 and a gauge 15 or 14, the light beam 71 is not obstructed or affected by the movement transformation mechanism 72, 73. In contrast, as soon as a gauge moves as a result of coming into contact with the container, the movement transformation mechanism 72, 73 is operated to obstruct the light beam 71 in order to detect that contact has occurred. In other words, the movement transformation mechanism 72, 73 creates an obstruction in the light beam so that the change of obstruction state in the light beam as detected by the emitter and receiver system 70 serves to signal that the gauge has come into contact.

(38) In another variant embodiment of the invention, the light beam 71 is obstructed by the movement transformation mechanism 72, 73 in the absence of relative movement between the movable equipment 6 and a gauge 15 or 14. Each detection system 35, 37 for detecting contact of a gauge includes a respective movement transformation mechanism 72, 73 for transforming the travel movement of a gauge 15, 14 relative to the movable equipment 6 into movement that eliminates or removes the obstruction of the light beam 71. Thus, the change in the beam obstruction state is detected by the emitter and receiver system 70, which indicates that the gauge has come into contact by means of the emitter and receiver system 70, regardless of the position of the movable equipment 6. In other words, an occurrence of contact causes a gauge 15, 14 to move relative to the movable equipment 6 so that the movement transformation mechanism 72, 73 allows the light beam 71 to pass. This way of detecting contact by passing the beam is the inverse (or dual) of detecting by obstructing the beam, and is equivalent thereto.

(39) In general manner, each movement transformation mechanism 72, 73 includes a target 74 suitable: in the absence of a movement of the gauge, for occupying a rest first position in which the target 74 is disengaged from the light beam 71 (FIG. 1), or in which the target 74 obstructs the light beam 71; and in the presence of relative movement between a gauge and the movable equipment 6, for occupying a second position referred to as a detection position in which the target 74 obstructs the light beam 71 (FIG. 2), or respectively in which the target 74 ceases to obstruct the light beam 71.

(40) Advantageously, each movement transformation mechanism 72, 73 is of the mechanical type, i.e. it does not require any electrical or mechanical connection between the movable equipment 6 and the stationary frame 7. For this purpose, the movement transformation mechanisms 72, 73 are interposed between the movable equipment 6 and the gauges 14, 15 or members that are associated therewith.

(41) In the example shown in FIGS. 1 and 2, the movement transformation mechanisms 72, 73 transform the linear travel movement of the gauges into pivoting movement of the respective target 74 in a plane containing a light beam. In this example, each movement transformation mechanism 72, 73 comprises a hinged scissors linkage 75 mounted between the movable equipment 6 and a gauge 14, 15. As can be seen in the example shown in FIGS. 1 and 2, the movement transformation mechanism 72 of the internal gauge 15 has scissors 75 with a first branch connected via a hinge 76 to the end of the rod 60 projecting from the jacket 49 and remote from the bottom first end that is secured to the internal gauge 15. The second branch of the scissors 75 is provided with the target 74 at its end opposite from its end connected via a pivot to the first branch, and it is connected by a hinge 77 to the movable equipment 6, and in particular to the connection part 48.

(42) The transformation mechanism 73 of the external gauge 14 includes scissors 75 having a first branch connected by a hinge 76 to the second end 20 of the external gauge 14. The second branch of the scissors 75 is provided with the target 74 at its end opposite from its end connected by a pivot to the first branch, and it is connected by a hinge 76 to the movable equipment 6, and in particular to the part 46 that serves to hold the external gauge 14.

(43) In the example shown in FIG. 4, each movement transformation mechanism 72, 73 transforms the linear travel movement of the gauges into rotary movement in a plane perpendicular to the direction of the light beam 71. In this example as shown, the movement transformation mechanisms 72, 73 include respective helical connections 80 associated with a planar linkage so as to enable the target 74 to be moved with a rotary movement in a plane perpendicular to the direction of the light beam 71. Thus, for the transformation mechanism 72 for transforming movement of the internal gauge 15, the sliding element of the helical connection 80 is connected to the end of the rod 60 that projects from the jacket 49, while the rotary element is connected to the movable element of the planar linkage 81 carrying the target 74. The movable element of the planar linkage is guided by the connection part 48.

(44) Likewise, for the transformation mechanism 73 for transforming the movement of the external gauge 14, the sliding element of the helical connection 80 is connected to the second end 20 of the external gauge 14, while the rotary element is connected to the movable element of the planar linkage 81 that carries the target 74. The movable element of the planar linkage 81 is guided by the part 46.

(45) Naturally, the transformation mechanisms 72, 73 may be made in manners other than those shown in the drawings. Likewise the emitter and receiver system 71 for transmitting and receiving the light beam may be made in any appropriate manner. For example, in the example shown in FIGS. 1 and 2, the emitter and receiver system 70 for transmitting and receiving the light beam 71 includes a light beam emitter E and a light beam receiver R that are mounted facing each other while spaced apart by not less than the maximum stroke of the movable equipment, such a system commonly being referred to as a light barrier or a fork.

(46) In the example shown in FIG. 3, the system 70 for emitting the light beam 71 includes a light beam emitter E and receiver R that are mounted together and opposite from or facing a light reflector R.sub.1.

(47) The occurrences of contact as detected by the detection systems 35, 37 are transmitted to the processor unit 31 which is capable, on the basis of the measurements delivered by the system 30 for measuring the position of the movable equipment 6, of determining whether the rings and the necks of containers 2 have dimensions that are in compliance. Each contact position of the gauges 14, 15 corresponds to a different dimensional inspection of the ring and of the neck of the container. By using a calibration operation, it is possible to determine the theoretical vertical positions for the gauges 14 and 15 that correspond to a container without defect, and consequently also the positions that correspond to a container with a defect.

(48) Since the position of the movable equipment 6 is known relative to the frame 7, i.e. also relative to the plane on which the containers 2 stand, the processor unit is suitable for determining the heights of the containers on the basis of contacts occurring between the external gauge 14 and the ring of the container and/or contacts occurring with the internal gauge 15.

(49) The operation of the inspection device 1 stems directly from the above description.

(50) After bringing a container 2 into register with the inspection device 1, the motor system 9 is controlled to lower the movable equipment 6. As soon as a gauge 14, 15 comes into contact with the container 2, that contact is detected by the associated detection system 35, 37. At that instant, by means of the measurement system 30, the processor unit 31 knows the position of the gauge that has come into contact with the container, thereby enabling the processor unit 31 to determine whether the dimensions of the container are in compliance and to determine the types of defect it detects on containers that are dimensionally not in compliance. Advantageously, as a function of contacts being detected with the two gauges 14, 15 and as a function of the measurement system 30, the processor unit 31 knows the positions of the movable equipment 6 at the instants the gauges 14, 15 come into contact with the container 2. Using these measurements and the occurrences of contact, the processor unit 31 performs calculations giving additional dimensional information about the necks and the rings of the containers 2, and in particular about the types of defect that are presented by the containers 2.

(51) Thus, as a function of the vertical position occupied by each of the gauges 14, 15 on making at least one contact with the container, the processor unit 31 is in a position to determine precisely whether the ring and the neck of the container have dimensions that are in compliance. As explained above, as a function of the vertical position occupied by each of the gauges 14, 15 when at least one contact occurs with the container, the processor unit 31 is capable of determining precisely whether the ring and the neck of the container have dimensions in compliance, since it is possible to determine defect types from among the following: a defect of the inside diameter of the neck that is less than a minimum acceptable diameter (a plug defect); a defect of the bore diameter being less than a minimum acceptable diameter (a bore defect); a defect of the bore diameter being greater than a maximum acceptable diameter (a bore defect); a height defect greater than a maximum acceptable height; a height defect less than a minimum acceptable height; an outside diameter defect less than a minimum acceptable diameter; and an outside diameter greater than a maximum acceptable diameter.

(52) It should be observed that as a result of detecting contact between one and/or both of the gauges 14, 15 with the container 2, and depending on the measured position of the movable equipment 6, the processor unit 31 can reverse the travel direction of the motor system so as to cause the movable equipment 6 to rise. In practice, for containers of dimensions that are in compliance, the gauges 14 and 15 come into contact with the container 2 substantially simultaneously. When there is no container (FIG. 5H), none of the detection systems 35, 37 detect contact. The processor unit 31 can then cause the movable equipment 6 to move upwards by controlling the motor system 9 once the movable equipment 6 has reached a previously determined low vertical position.

(53) The invention is not limited to the embodiments described and shown since various modifications can be made thereto without going beyond its ambit.