Device for detecting speed and length of corrugated pipe and winding machine for packaging corrugated pipe

Abstract

There is described a device (10) for detecting the speed (v) and length (L) of a bellows (2) moving along a processing path (P), the device being provided with: a camera (11) arranged, in use, in a position facing the bellows (2) and at a non-zero distance from the bellows (2) and configured to take an image of at least a longitudinal portion of the bellows (2); and a control module (13) connected to the camera (11) and configured to calculate a feed speed (v) of the bellows (2) and a length (L) of the bellows (2) based on the image detected by the camera (11).

Description

[0001] Cross-citation of related applications

[0002] This patent application claims priority to Italian Patent Application No. 102024000021975, filed on October 3, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to a device for detecting the speed and length of a corrugated pipe. The invention also relates to a winding machine for packaging corrugated pipes, particularly a winding machine for packaging corrugated pipes using a stretch film of plastic material, the winding machine being equipped with a device for detecting the speed and length of the corrugated pipe. Background Technology

[0004] As is known, in the field of extrusion of flexible corrugated pipes of plastic materials, a winding machine suitable for packaging flexible corrugated pipes into coils of a predetermined length has been manufactured. The winding machine includes: a winding unit for forming a corrugated pipe coil; a packaging unit arranged downstream of the winding unit and manufactured to bundle or wind the coil; and a coil exit station.

[0005] The winding machine also includes an inlet station adapted to continuously feed the bellows from the extrusion unit to the winding unit. Finally, the inlet station includes an inlet cone configured to receive the tube and transfer it to the winding unit.

[0006] The winding machine is also equipped with a detection device located in the area of ​​the inlet station and configured to detect the feed speed and length of the bellows. Typically, the detection device includes an electromechanical contact, preferably an encoder mechanically connected to the measuring wheel or track. Known types of detection devices have several disadvantages, particularly stemming from the fact that the contact between the device and the corrugated (discontinuous) profile of the tube's outer surface significantly affects the measurement. Encoder wheels can be used where the lower accuracy due to jumps caused by the tube's corrugations is acceptable, provided the pitch between the corrugations is on the order of 3 mm to 10 mm, and in any case, the diameter of commercially available and readily available encoder wheels is limited. Encoder wheels are unsuitable when the pitch between the corrugations is large. Furthermore, the application of encoder wheels requires a tube guiding system that keeps the tube perfectly straight to prevent any wrinkles from exacerbating the problem of reading the length of the tube passing beneath the encoder wheel itself. Additionally, the wound tube undergoes elastic axial tension, which then recovers during winding, resulting in a tube length measured by the aforementioned encoder wheel that is greater than the actual wound length. A track measuring device can be used to replace the encoder wheel, but this device will not improve the system's accuracy. In fact, the track needs to be perfectly straight and have a perfectly flat contact surface. Furthermore, due to the elasticity of the tube, such a system is not without error.

[0007] Furthermore, there is an increasing demand for available devices that allow for the detection of both the speed and length of bellows.

[0008] Documents CN112461137, CN204748693 and GB2283197 describe apparatus for detecting the length of bellows of known types. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a device for detecting the speed and length of a bellows, which does not have the disadvantages of the prior art and is easy and economical to implement.

[0010] Another object of the present invention is to provide a winding machine for packaging corrugated pipes made of plastic material, which does not have the disadvantages of the prior art, and is easy to use and economical to manufacture.

[0011] According to the present invention, an apparatus for detecting the speed and length of a corrugated pipe as claimed in the appended claims and a winding machine for packaging corrugated pipes are provided. Attached Figure Description

[0012] The invention will now be described with reference to the accompanying drawings, which illustrate some non-limiting examples of embodiments, in which:

[0013] - Figure 1This is a schematic side view of a winding machine manufactured according to the present invention, wherein some parts have been removed for clarity;

[0014] - Figure 2 This is a schematic diagram of a device for detecting the speed and / or length of a bellows, manufactured according to the present invention, with some components omitted for clarity; and

[0015] - Figure 3 Indicates by Figure 2 The image detected by the optical sensor of the detection device. Detailed Implementation

[0016] exist Figure 1 In the text, the number 1 represents the winding machine used for packaging the flexible corrugated pipe 2.

[0017] The bellows 2 is defined by alternating crests (or ridges) C and troughs G (or troughs), the crests having a constant width denoted by a and the troughs having a constant width denoted by b. The distance between two crests is given by the sum of lengths a and b, and defines the bellows pitch of the bellows 2. The bellows 2 moves along the processing path P.

[0018] The winding machine 1 includes multiple operating stations arranged along the processing path P. More specifically, the winding machine 1 includes: a winding unit 3 of a known type for forming coils (not shown) of the corrugated pipe 2; a packaging unit 4 arranged downstream of the winding unit 3 along the processing path P and configured to strap and / or wrap plastic film around the coils of the corrugated pipe 2; and an exit station 5 for the coils of the corrugated pipe 2, which is arranged downstream of the packaging unit 4 along the processing path P.

[0019] The winding machine 1 also includes a feed station 6, which is arranged upstream of the winding unit 3 along the processing path P. The feed station 6 is configured to continuously supply the bellows 2 from the extrusion unit (not shown) to the winding unit 3. Finally, the winding machine 1 includes a base 7 that supports the feed station 6 and houses the winding unit 3 and the packaging unit 4 within the base.

[0020] The feed station 6 includes an inlet cone 8, which is supported by a base 7 and configured to receive the bellows 2 and feed it to the winding unit 3.

[0021] The winding machine 1 includes a control device 9 having at least one electronic control unit CU configured to monitor the operation of the winding machine 1.

[0022] The control device 9 includes a detection device 10. The detection device 10 is arranged along the processing path P; more specifically, the detection device 10 is arranged in the area of ​​the feed station 6. The detection device 10 is configured to detect the feed speed v and / or length L of the bellows 2.

[0023] The detection device 10 includes at least one (optical) sensor 11 configured to at least frame a longitudinal portion of the bellows 2. Advantageously, the sensor 11 is non-contact. Advantageously, the sensor 11 is a camera 11. In use, the camera 11 is positioned facing the bellows 2. In use, the camera 11 is positioned at a non-zero distance from the bellows 2.

[0024] Preferably, the longitudinal portion of the bellows 2 framed by the camera 11 includes a plurality of peaks C and recesses G. Even more preferably, the longitudinal portion of the bellows 2 framed by the camera 11 includes a plurality of (at least two) peaks C and recesses G. Depending on the size of the bellows 2, the camera 11 is arranged to frame the entire section of the longitudinal portion of the bellows 2, or alternatively, to frame only a portion of the longitudinal portion of the bellows 2 (obviously, the portion provided with peaks C and recesses G).

[0025] The detection device 10 also includes at least one backlight illumination device 12. In use, the backlight illumination device 12 is also positioned facing the bellows 2. In use, the backlight illumination device 12 is positioned at a non-zero distance from the bellows 2. More specifically, when in use, the backlight illumination device 12 and the camera 11 are arranged on opposite sides of the bellows 2; in other words, the bellows 2 advances in the direction indicated by D and is positioned between the backlight illumination device 12 and the camera 11. The backlight illumination device 12 is configured to illuminate the longitudinal portion of the bellows 2 framed by the camera 11. The presence of the backlight illumination device 12 makes it easier to detect the shape of the bellows 2 defined by the alternation of crests C and recesses G.

[0026] The detection device 10 finally includes a control module 13. The control module 13 is configured to receive signals from the camera 11 and determine the feed speed v of the bellows 2 and the length L of the bellows 2 based on the signals.

[0027] More specifically, control module 13 is configured as follows:

[0028] - Calculate the number n of wave crests C contained in the longitudinal portion of the bellows 2 framed by camera 11 during the detection time window Δt. R ;as well as

[0029] - Based on the number n of the wave crests C (included in the longitudinal portion of the bellows 2 framed by camera 11 during the detection time window Δt). R Calculate the feed speed v of bellows 2 and / or the length L of bellows 2.

[0030] More specifically, control module 13 is configured to calculate the feed speed v of bellows 2 using the following formula:

[0031] v=(n R *d) / Δt [1]

[0032] in,

[0033] v represents the feed speed of bellows 2;

[0034] Δt represents the detection time window;

[0035] n R This indicates the number of peaks C during the detection time window Δt; and

[0036] d represents the distance between two successive wave crests C.

[0037] Furthermore, the control module 13 is configured to calculate the length L of the bellows 2 using the following formula:

[0038] L=L'+(n R *d) [2]

[0039] in,

[0040] L represents the update length of bellows 2;

[0041] L' represents the length of the bellows 2 calculated in the previous detection time window Δt;

[0042] n R Indicates the number of peaks; and

[0043] d represents the distance between two successive wave crests C.

[0044] The detection time window Δt has a constant amplitude, which is determined in the preliminary step of calibrating the detection device 10.

[0045] Advantageously, the distance d between the two wave crests C is also determined in the preliminary step of calibrating the detection device 10. Preferably, a mapping of the distance d between two successive wave crests C based on multiple parameters is stored in the control module 13; specifically, the parameters include the diameter of the bellows 2.

[0046] Number of peaks n R The detection time window Δt is determined by processing the image detected by camera 11 during that window. Advantageously, control module 13 is configured to:

[0047] - Capture multiple images (frames) detected by camera 11 during the detection time window Δt;

[0048] - Optionally, each captured image can be converted to a grayscale image (if the image was not originally captured in grayscale).

[0049] - Construct a binary image from each grayscale image; in each binary image, each pixel is associated with black when it is within the shape of the bellows 2, or alternatively, with white; and

[0050] - Detect the number of black pixels in at least one control segment of each binary image.

[0051] Finally, control module 13 is configured to calculate the number of peaks n during the detection time window Δt based on the number of black pixels in the control segment of the binary image. R .

[0052] Control module 13 is connected to control unit CU, which sends signals to control unit indicating the feed speed v of bellows 2 and the length L of bellows. Therefore, control unit CU is configured to control winding unit 3 based on the signals sent by control module 13; specifically, based on the length of the wound bellows 2; more specifically, control unit CU is configured to determine when the predetermined length of bellows 2 has been reached based on the length of the coil to be wound.

[0053] Advantageously, the control module 13 is integrated into the camera 11 and connected to a control unit CU that communicates with the control module. Alternatively, the control module 13 is integrated into the control unit CU and connected to the camera 11 that communicates with the control module.

[0054] The feed station 6 also includes a support structure 14 having at least a first bracket (not shown) for supporting the camera 11 and at least a second bracket (not shown) for supporting the backlight illumination device 12.

[0055] According to a preferred embodiment, the detection device 10 includes a support element 15 for the bellows 2. The support element 15 is configured to support the bellows 2 in a channel between the camera 11 and the backlight illumination device 12 to suppress vibrations of the bellows 2 within the reading range of the camera 11. The support element 15 includes a plurality of rollers 16 configured to support and guide the bellows 2 through the feed station 6. Preferably, (non-exclusively) the support element 15 includes a plurality of double-conical rollers 16 configured to support the bellows 2. The double-conical rollers 16 are provided with axes parallel to each other.

[0056] More specifically, the support element 15 includes a plurality of double-conical rollers 16, specifically four double-conical rollers 16; preferably, the four double-conical rollers 16 are divided into two pairs of double-conical rollers 16. One pair (the first pair) of double-conical rollers 16 is arranged at the entrance of the feed station 6, wherein (the first) double-conical roller 16A is arranged below the bellows 2, and (the second) double-conical roller 16B is arranged above the bellows 2. A pair (the second pair) of double-conical rollers 16 is arranged at the exit of the feed station 6, wherein (the third) double-conical roller 16C is arranged below the bellows 2, and (the fourth) double-conical roller 16D is arranged above the bellows 2.

[0057] Alternatively, the support element 15 includes a plurality of double conical rollers 16, specifically two double conical rollers 16. (First) double conical roller 16A is arranged below the bellows 2 at the entrance of the feed station 6, and (second) double conical roller 16C is arranged below the bellows 2 at the exit of the feed station 6.

[0058] According to another variation, the support element 15 comprises a plurality of shaped flat metal sheets, and preferably, these shaped flat metal sheets are coated with a low coefficient of friction material.

[0059] In the preceding discussion, reference has been made to the case of winding machine 1, but the detection device 10 may also find advantageous applications in other machines (e.g., in machines used for cutting bellows 2).

[0060] It is important to point out that in the detection device 10 described in the preceding discussion, there is no sensor specifically for detecting the feed rate v; instead, the feed rate v and length L of the bellows 2 are determined by images detected by the camera 11.

[0061] The detection device 10 and the winding machine 1 described in the preceding discussion have several advantages; specifically, the detection device 10 is quick to set up and adjust, can be easily adapted to bellows 2 of different types and sizes (referring only to the distance between two successive crests C), and ensures reliable and robust measurement of the feed speed v of the bellows 2 (even when the feed speed v is variable) and length L, regardless of environmental conditions and the vibrations and deformations experienced by the bellows 2.

[0062] List of reference numerals

[0063] 1 Winding machine

[0064] 2-corrugated pipe

[0065] 3 winding units

[0066] 4 Packaging Units

[0067] 5 Exit Station

[0068] 6 feed stations

[0069] 7 base

[0070] 8-inlet cone

[0071] 9 Control Equipment

[0072] 10 Detection Devices

[0073] 11 cameras

[0074] 12 Backlighting Devices

[0075] 13 control modules

[0076] 14 Supporting Structure

[0077] 15 Supporting Components

[0078] 16A roll

[0079] 16B roll

[0080] 16C roll

[0081] 16D roller

[0082] C peak

[0083] G concavity

[0084] a width

[0085] b width

[0086] P path

[0087] CU control unit

[0088] D direction

Claims

1. A device (10) for detecting the speed (v) and length (L) of a bellows (2) moving along a processing path (P), comprising: a) At least one camera (11) is arranged in use facing the bellows (2) and at a non-zero distance from the bellows (2); the camera (11) is configured to capture an image of at least a longitudinal portion of the outer surface of the bellows (2); b) A control module (13), connected to the camera (11), which receives images of the longitudinal portion of the outer surface of the bellows (2) from the camera, and is configured to calculate the feed rate (v) and length (L) of the bellows (2) based on the images detected by the camera (11); and The control module (13) is configured as follows: - Calculate the number (n) of peaks (C) contained in the longitudinal portion of the bellows (2) framed by the camera (11) during the detection time window (Δt). R );as well as - The number (n) based on the peak (C) R ) Calculate the feed rate (v) of the bellows (2) and the length (L) of the bellows (2).

2. The apparatus according to claim 1, wherein, The control module (13) is configured to calculate the feed rate (v) of the bellows (2) using the following formula: v=(n R *d) / Δt [1] in, v represents the feed speed of the bellows (2); Δt represents the detection time window; n R This indicates the number of peaks (C) during the detection time window (Δt); and d represents the distance between two successive peaks (C).

3. The apparatus according to claim 1 or 2, wherein, The control module (13) is configured to calculate the length (L) of the bellows (2) using the following formula: L=L'+(n R *d) [2] in, L represents the update length of the bellows (2); L' represents the length of the bellows (2) calculated in the previous detection time window (Δt); n R Indicates the number of the wave peaks (C); and d represents the distance between two successive peaks (C).

4. The apparatus according to any one of the preceding claims further includes a backlight illumination device (12), which is arranged in use facing the bellows (2), at a non-zero distance from the bellows (2), and on the opposite side of the bellows (2) relative to the camera (11); wherein, The backlight illumination device (12) is configured to backlight the longitudinal portion of the bellows (2) framed by the camera (11).

5. A winding machine (1) for packaging flexible corrugated pipes (2), comprising: - A winding unit (3) for forming a coil of a bellows (2) arranged along the processing path (P); - A feed station (6) configured to continuously supply the bellows (2) arranged upstream of the winding unit (3) along the processing path (P); and - A device (10) for detecting the speed (v) and length (L) of the bellows (2) according to any one of the preceding claims, the device being arranged in the area of ​​the feed station (6).

6. The winding machine according to claim 5 further includes a control unit (CU) connected to the control module (13) and configured to control the winding unit (3) based on the feed speed (v) of the bellows (2) and / or the length (L) of the bellows (2).

Images