The present invention relates to a machine for processing articles, a control device, and a diagnostic method applied to such a machine.
More specifically, the present invention relates to a machine for processing articles and comprising a transfer device, which feeds the articles along a feed path from an input station to an output station, and comprises at least one seat and at least one operating component for moving the seat. During each operating cycle, the seat picks up a respective article at the input station, releases the article at the output station, and returns to the input station along a return path.
In known machines of the above type, it is relatively essential that the seat assume a precise position at the input and output stations to prevent the article from being damaged or even lost as it is picked up or released by the seat.
At present, faults on the transfer device resulting in incorrect positioning of the seats at the input and/or output station are extremely difficult and slow to determine. This, combined with the high operating speeds of modern machines for processing articles, therefore results in a relatively large number of rejects downstream from the transfer device and, consequently, in increased production costs.
It is an object of the present invention to provide a machine for processing articles and a diagnostic method, which are designed to eliminate the aforementioned drawbacks, and which, in particular, are cheap and easy to implement.
According to the present invention, there is provided a diagnostic method as claimed in the attached Claims.
According to the present invention, there is provided a machine for processing articles, as claimed in the attached Claims.
According to the present invention, there is provided a control device as claimed in the attached Claims.
A number of non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:
Number 1 in
Transfer device 5 comprises a conveyor roller 8, which rotates about a respective horizontal axis of rotation 9 and has a number of peripheral housings 10 equally spaced about axis 9 and each comprising two elongated, substantially coaxial seats 11 and 11′, each having an externally concave surface with suction nozzles. Roller 8 comprises an operating unit 12 (shown partly) for moving seats 11 and 11′ longitudinally and parallel to axis 9, and which comprises a number of rods 12′. Each rod 12′ supports a respective seat 11 and 11′, and slides longitudinally in a direction parallel to axis 9.
In the tobacco industry, transfer device 5 is normally used to part two cigarettes 2 just formed by transversely cutting a double cigarette (not shown).
In actual use, when a housing 10a, comprising two seats 11a and 11′a, is located at input station 4, the two seats 11a and 11′a receive respective cigarettes 2 positioned with the respective filter ends facing. At this point, as roller 8 rotates about axis 9 and housing 10a travels along path P1, seats 11a and 11′a are parted axially and parallel to axis 9 (
Machine 1 also comprises a control device 13 for ensuring seats 11, 11′ are positioned correctly along feed and return paths P1 and P2. Control device 13 comprises two proximity sensors 14, 14′, each for emitting a recording signal S relative to the position of a respective seat 11, 11′ of each housing 10; and a computer 15 connected to sensors 14, 14′ and for comparing recording signal S with a reference data item DR to obtain at least one comparison data item DC from which to determine a fault on operating unit 12.
In the present description, the term “fault” is intended to mean an operating condition which is already causing production problems, e.g. a relatively high percentage of reject cigarettes, or a condition which, if not corrected, would presumably result in production problems.
As described herein, reference data item DR may comprise one or more elements, e.g. may be a single value or a matrix of values. Similarly, comparison data item DC may comprise one or more elements, e.g. may be a single value or a matrix of values.
Computer 15 may acquire a recorded data item as a function of recording signal S and subtract the recorded data item from a reference data item DR value to obtain a comparison data item DC value; and, in the event the comparison data item DC value exceeds a given threshold value, control device 13 informs the user of the fault by means of acoustic and/or visual signals and/or stops machine 1.
With reference to one seat 11a, in actual use, proximity sensor 14 emits a signal Sa every time seat 11a travels past sensor 14. Signal Sa has a peak PR indicating the minimum distance between seat 11a and proximity sensor 14, and which has a respective recorded height h, and a minimum machine angle AM corresponding to the instant in which peak PR is recorded. Computer 15 preferably processes signal Sa from sensor 14 to obtain a response curve C1 (shown in
More specifically, given the externally concave surface of seat 11a, curve C1 is substantially W-shaped, and has peak PR and a groove GR, which indicates the maximum distance between the seat and the sensor, and which has a respective recorded height h′.
In the present description, the term “machine angle” is intended to mean a given point in an operating cycle at which transfer device 5 assumes a given operating configuration typical of that point. If transfer device 5 is operated at constant speed, the same machine angles of successive operating cycles follow one another at constant time intervals of a duration equal to the duration of one operating cycle.
In some embodiments, peak PR is compared with reference data item DR to obtain comparison data item DC. In particular, recorded height h may be compared with reference data item DR to determine the correct radial position of seat 11a with respect to axis 9; and minimum machine angle AM may be compared with reference data item DR to determine the correct angular position of seat 11a with respect to axis 9.
Alternatively or in addition, reference data item DR comprises a reference curve C2; and computer 15 compares response curve C1 with reference curve C2 to obtain comparison data item DC comprising information relating to the angular and radial position of seat 11a with respect to axis 9.
Alternatively or in addition, computer 15 determines a neighbourhood of peak PR having a given area A, and identifies a mid-line M of area A (i.e. a line dividing area A into two portions of equal area) having a constant minimum machine angle T1, which is compared with reference data item DR (e.g. the machine angle of a mid-line of curve C2) to obtain comparison data item DC comprising information relative to the angular position of seat 11a with respect to axis 9.
Alternatively or in addition, computer 15 determines the recorded height h′ of groove GR; and recorded height h′ is compared with reference data item DR to obtain comparison data item DC comprising information relative to the radial position of seat 11a with respect to axis 9.
In a further embodiment, alternatively or in addition to the above, curve C1, peak PR, groove GR, machine angle AM, mid-line M, machine angle T1, recorded height h and/or recorded height h′ are calculated by computer 15 on the basis of the mean of a number of signals Sa emitted by sensor 14 during successive operating cycles.
It should be pointed out that, in the present description, the operations referred to as being performed by computer 15 on recording signals S (e.g. comparisons, mean calculations, and time patterns) are intended as being performed directly on recording signals S or on the processing (acquired data) of recording signals S.
Alternatively or in addition, during each operating cycle, computer 15 compares curve C1, peak PR, groove GR, machine angle AM, mid-line M, machine angle T1, recorded height h and/or recorded height h, with reference data item DR to obtain a number of comparison data items DC, each relating to a respective operating cycle; and computer 15 determines and employs a mean of said comparison data items DC to identify a possible machine fault.
In a further embodiment, in addition to or instead of the above embodiments, one or more test curves are determined by which to extrapolate the time pattern of at least one of the following data items: curve C1, peak PR, groove GR, machine angle AM, mid-line M, machine angle T1, recorded height h, recorded height h′ (i.e. the recorded data) and/or comparison data item DC. Maintenance work is programmed as a function of the instants in which one or more test curves intersect respective reference curves of reference data item DR. More specifically, maintenance may be programmed at the exact instant in which a test curve intersects the respective reference curve, or at a given time interval before or after the instant in which a test curve intersects the respective reference curve.
Purely by way of example,
As shown in
By comparing at least one of recorded data items C1, PR, GR, AM, M, T1, h and h′ with reference data item DR and so determining comparison data item DC, any incorrect positioning of seat 11a along paths P1 and P2, and therefore at input and output stations 4 and 6, can be determined quickly and easily.
It should be pointed out that the particular combination of component parts of control device 13 provides for programming maintenance to correct the fault in such a way as to prolong operation of machine 1 as long as possible before the fault can pose production problems on transfer device 5.
In particular, this is achieved in a particularly advantageous manner by determining the time pattern of recording signals S, comparison data items DC and/or mean values thereof.
Computer 15 processes the signal from sensor 14′ in the same way as recording signal Sa from sensor 14, to preferably obtain at least one of the following recorded data items: curve C1, peak PR, groove GR, machine angle AM, mid-line M, machine angle T1, recorded height h, recorded height h′.
In further embodiments, in addition to or instead of the above embodiments, at least one recorded data item C1, PR, GR, AM, M, T1, h and h′ relative to a signal emitted by sensor 14′ forms part of reference data item DR. In which case, at least one of recorded data items C1, PR, GR, AM, M, T1, h and h′ relative to the signal emitted by sensor 14 is therefore compared with at least one of the corresponding recorded data items C1, PR, GR, AM, M, T1, h and h′ relative to the signal emitted by sensor 14′, in addition to or instead of given data items forming part of reference data item DR.
The term “given data items” is intended to mean data items relative to an ideal position of seat 11a with respect to axis 9.
In this way, a double check is made of the correct position of seat 11a: with respect to its own ideal position, and with respect to the position of seat 11′a. In this connection, it is important to stress that, for cigarettes 2 to be transferred correctly at input station 4 and output station 6, seats 11a and 11′a must be positioned correctly both with respect to each other and with respect to their ideal positions.
Machine 1 in
Seats 11 and 11′ are not movable axially and parallel to axis 9 with respect to one another. More specifically, seats 11′ are connected integrally to conveyor roller 8; and operating unit 12 moves seats 11 radially with respect to axis 9, and rotates seats 11 about respective axes 16 substantially crosswise to axis 9.
Transfer device 5 in
In actual use, when a housing 10, comprising two seats 11 and 11′, is located at input station 4, the two seats 11 and 11′ are substantially coaxial with each other, and each receive a respective cigarette 2. At this point, as roller 8 rotates about axis 9 and housing 10 travels along a feed path P1, seat 11 moves radially with respect to and away from axis 9, and then rotates about axis 16 into a position parallel to respective seat 11′. At output station 6, cigarettes 2, arranged in twos with their filters side by side in seats 11 and 11′, are unloaded onto conveyor wheel 7. As housing 10 returns to input station 4 along a return path P2, seat 11 repeats in reverse the same movements performed along feed path P1, so that it is once more positioned coaxially with seat 11′ by the time housing 10 reaches input station 4.
Machine 1 in
Control device 13′ differs from control device 13 by having only one proximity sensor 14 located along return path P2 at input station 4. Location of sensor 14 at input station 4 provides for determining, to a relatively high degree of precision, whether seat 11 is restored to a position substantially coaxial with seat 11′.
In a particularly preferred embodiment, in actual use, sensor 14 emits recording signal S as a seat 11 travels past sensor 14; signal S is processed by computer 15 to obtain curve C1; and, at this point, the machine angle of peak PR and the value of height h of peak PR are obtained and compared with reference data item DR. More specifically, the difference between the machine angle of peak PR and a reference machine angle is determined; and, when the difference between the machine angle of peak PR and the reference machine angle is above (or below) a given threshold value, control device 13′ emits an error signal indicating a fault relative to incorrect rotation of seat 11 about axis 16. Similarly, computer 15 subtracts the value of height h of peak PR from a reference height value; and, when the difference between the value of height h of peak PR and the reference height value is above (or below) a given threshold value, control device 13′ emits an error signal indicating a fault relative to incorrect radial movement of seat 11.
For a clearer understanding of the operation of control device 13,
Number | Date | Country | Kind |
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B02005A 000204 | Mar 2005 | IT | national |