A clamping and positioning device for steel wire rope flaw detection

Abstract

The application discloses a clamping and positioning device for steel wire rope flaw detection, which comprises a clamping mechanism and a positioning mechanism, the clamping mechanism comprises clamping wheels and a scale, the clamping wheels are two and are distributed side by side on the left and right sides of the steel wire rope, the clamping wheel comprises a rotating disc and a rotating opening and closing disc, the rotating opening and closing disc is installed in the rotating disc, comprises a plurality of tooth pieces distributed in a ring, and each tooth piece has a movement stroke of rotating and opening and extending or closing and retracting the rotating disc. In the application, the clamping mechanism can clamp the steel wire rope from any position by adjusting the two clamping wheels distributed side by side along the scale, and the clamping mechanism does not need to be sleeved from the end of the steel wire rope, and then the rotating opening and closing disc is adjusted by rotating, in the state that the tooth pieces are rotated and extended, the tooth pieces are locked with the steel wire rope, the clamping wheel is prevented from moving, and the clamping mechanism is strengthened to clamp the steel wire rope.

Description

Technical Field

[0001] This invention relates to the field of wire rope testing technology, and more specifically to a clamping and positioning device for wire rope flaw detection. Background Technology

[0002] Wire ropes are frequently used in many heavy industries and high-risk sectors, such as mining, construction, port loading and unloading, and offshore drilling, for lifting, hoisting, and carrying heavy objects. Under prolonged exposure to heavy pressure and continuous friction, or after use under extreme conditions, wire ropes can develop safety hazards such as wear, corrosion, and fatigue fracture. If these problems are not detected and addressed promptly, they can lead to sudden breakage of the wire rope, causing serious accidents such as falling objects and equipment overturning, endangering the lives of operators and surrounding workers. Therefore, regular wire rope flaw detection can promptly identify safety hazards, and by taking necessary maintenance or replacement measures, the potential risks in the workplace can be significantly reduced.

[0003] When inspecting steel wire ropes, the selected section to be inspected needs to be straightened and fixed in advance. The fixing device in the existing technology generally adopts a set structure, which is sleeved along the steel wire rope and slides until it moves to the selected section to be inspected and is positioned and fixed. This device is not convenient and flexible in operation, and it is difficult to meet the requirements of rapid positioning and stable fixing of any selected section of the steel wire rope. Summary of the Invention

[0004] The present invention provides a flexible and convenient clamping and positioning device for wire rope flaw detection, which can solve at least one of the above-mentioned technical problems.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a clamping and positioning device for wire rope flaw detection, for wire rope, including a clamping mechanism and a positioning mechanism, wherein the clamping mechanism is horizontally clamped at any part of the wire rope, and the positioning mechanism is vertically clamped along the length direction of the wire rope and is connected to the clamping mechanism at intervals.

[0006] The clamping mechanism includes clamping wheels and a ruler. There are two clamping wheels, which are arranged side by side on the left and right sides of the wire rope. One wheel is fixedly installed with the ruler, and the other wheel is slidably installed with the ruler. The clamping wheel includes a turntable and a rotating opening and closing disc. The rotating opening and closing disc is fitted inside the turntable and includes a plurality of circumferentially distributed toothed plates. Each toothed plate has a rotational stroke to open and extend or close and retract the turntable.

[0007] The positioning mechanism includes a locking component and an anti-loosening component. The locking component is installed on the wire rope with adjustable tension. There are two anti-loosening components, which are fixed on the left and right sides of the locking component respectively and are detachably connected to the two clamping wheels.

[0008] Furthermore, the positioning mechanism is located above or below the clamping mechanism and is connected to the clamping mechanism in a triangular structure.

[0009] Furthermore, the positioning mechanism has two parts, which are mirror images of the clamping mechanism above and below it, and are connected to the clamping mechanism in a triangular structure.

[0010] Furthermore, the ruler strip is perpendicular to the wire rope, one end of the ruler strip is a fixed end, the other end is an open end, and a groove is formed on the ruler strip along its length. The groove communicates with the open end. The clamping wheel located on one side of the wire rope is fixedly installed with the fixed end, and the clamping wheel located on the other side of the wire rope can slide along the groove through the open end until it abuts against the wire rope.

[0011] Furthermore, the two turntables abutting on both sides of the wire rope can rotate and rise synchronously along the length of the wire rope. Each turntable has an annular groove along its circumference and multiple limiting grooves are provided inside. Each toothed piece is fitted and clamped inside the turntable and slides and matches each of the limiting grooves one by one. Each toothed piece can slide around the center of the turntable and along the limiting groove, rotating out of the annular groove until it engages with and locks into the wire rope.

[0012] Furthermore, the engaging assembly includes an outer engaging tube, which includes an outer tube piece that can be opened and closed along the length of the wire rope. There are two outer tube pieces, each with a semi-circular arc plate structure. One end of each outer tube piece is connected by a spring-loaded hinge, and the other end of each outer tube piece is engaged by a toothed opening. Each outer tube piece has a handle fixed on the outer wall of the hinged end for opening or closing the toothed opening.

[0013] Furthermore, the engaging assembly also includes an inner tube and elastic elements. The inner tube is located inside the outer tube and is fixedly connected to the outer tube via multiple elastic elements. The inner tube has a semi-circular arc plate structure, which can fit against and elastically abut against the wire rope along its length.

[0014] Furthermore, multiple grooves are spaced apart on the inner wall surface of the inner tube segment, and each groove is fitted with a ball bearing that can roll and slide along the wire rope.

[0015] Furthermore, the anti-loosening component includes a T-shaped connector and a connecting piece. The T-shaped connector is fixed to the outer wall of the outer clamping tube. There are two connecting pieces, which are respectively disposed on both sides of the T-shaped connector. One end of each connecting piece is connected to the T-shaped connector, and the other end is connected to the center of the front or back of the turntable.

[0016] Furthermore, the clamping wheel also includes a locking component, which has multiple locking components and is detachably installed at the center positions of the front and back of the turntable. The locking component includes a washer and a locking bolt. The washer is attached to the ruler strip, and the locking bolt passes through the washer and is threaded into the turntable to lock the ruler strip, the rotating opening and closing disc, and the connecting piece.

[0017] The beneficial effects of this invention are reflected in:

[0018] 1. In this invention, the clamping mechanism can clamp the wire rope from any position by adjusting two clamping wheels arranged side by side along the ruler strip, without needing to fit it from the end of the wire rope. The operation is flexible and convenient. By rotating and adjusting the rotating opening and closing disc, the two clamping wheels clamp the wire rope relative to each other when the toothed plate is rotated and retracted, and can move synchronously along the wire rope to further adjust the specific clamping position. When the toothed plate is rotated and extended, the toothed plate bites and locks with the wire rope to prevent the clamping wheels from moving, thereby strengthening the clamping mechanism's firmness in clamping the wire rope.

[0019] 2. In this invention, the positioning mechanism is used in conjunction with the clamping mechanism to clamp and fix the steel wire rope at the upper end, lower end, or both ends of the clamping mechanism along the length direction. It also eliminates the need to fit the steel wire rope from the end, making the operation flexible and convenient. It is used to isolate the section of the steel wire rope to be tested from other parts, reduce the interference caused by disturbances from other parts to the section to be tested, and improve the accuracy of the test.

[0020] 3. In this invention, the positioning mechanism and the clamping mechanism are detachably connected. The locking component, the anti-loosening component, the clamping wheel and the ruler are located outside the wire rope and are connected in sequence to form a triangular structure, which further improves the firmness of the wire rope clamping. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the assembly of the overall device of the present invention with the wire rope in the open state of the clamping mechanism teeth.

[0022] Figure 2 This is a schematic diagram of the assembly of the overall device of the present invention with the wire rope in the closed state of the clamping mechanism teeth.

[0023] Figure 3 This is a schematic diagram of the overall structure of the clamping mechanism with the teeth open in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram illustrating the switching of the rotating opening and closing disc from closed to open according to an embodiment of the present invention.

[0025] Figure 5 This is a front structural cross-sectional view of the locking assembly and wire rope in an embodiment of the present invention.

[0026] Figure 6 This is a top view of the positioning mechanism according to an embodiment of the present invention.

[0027] The components in the attached diagram are labeled as follows: 1. Steel wire rope; 2. Clamping mechanism; 3. Positioning mechanism; 4. Clamping wheel; 5. Ruler strip; 501. Fixed end; 502. Open end; 503. Slide groove; 6. Engaging assembly; 7. Anti-loosening assembly; 8. Turntable; 9. Rotary opening and closing disc; 901. Toothed plate; 10. Locking element; 11. Outer clamping tube; 1101. Outer tube; 1102. Spring; 1103. Handle; 1104. Toothed opening; 12. Inner tube; 1201. Ball bearing; 13. Elastic element; 14. T-shaped connecting seat; 15. Connecting piece. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indicators will also change accordingly. In addition, the meaning of "and / or" in the whole text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B. In addition, "multiple" refers to two or more.

[0029] See Figure 1-2 This invention provides a clamping and positioning device for wire rope flaw detection, for wire rope 1, including clamping mechanism 2 and positioning mechanism 3. The clamping mechanism 2 is horizontally clamped at any part of the wire rope 1, and the positioning mechanism 3 is vertically clamped along the length direction of the wire rope 1 and is connected to the clamping mechanism 2 at intervals.

[0030] The clamping mechanism 2 includes clamping wheels 4 and ruler strips 5. There are two clamping wheels 4, which are arranged side by side on the left and right sides of the wire rope 1. One of them is fixedly installed with the ruler strip 5, and the other is slidably installed with the ruler strip 5. The clamping wheel 4 includes a turntable 8 and a rotating opening and closing disc 9. The rotating opening and closing disc 9 is fitted inside the turntable 8 and includes a plurality of circumferentially distributed toothed plates 901. Each toothed plate 901 has a rotational stroke to open and extend or close and retract the turntable 8.

[0031] The positioning mechanism 3 includes a locking component 6 and an anti-loosening component 7. The locking component 6 is installed on the wire rope 1 with adjustable tension. There are two anti-loosening components 7, which are fixed on the left and right sides of the locking component 6 respectively and are detachably connected to the two clamping wheels 4.

[0032] In this invention, the clamping mechanism uses two parallel clamping wheels that slide along the ruler to clamp the wire rope from any position, eliminating the need to attach them from the end of the wire rope. This makes operation flexible and convenient. By rotating and adjusting the rotating opening and closing disc, the two clamping wheels clamp the wire rope relative to each other when the toothed plates are retracted, and can move synchronously along the wire rope to further adjust the specific clamping position. When the toothed plates are extended, they engage and lock with the wire rope, preventing the clamping wheels from moving and strengthening the clamping mechanism's grip on the wire rope. The positioning mechanism works in conjunction with the clamping mechanism to clamp and fix the wire rope at the upper, lower, or both ends of the clamping mechanism along its length. Again, this eliminates the need to attach them from the end of the wire rope, making operation flexible and convenient. It isolates the section of the wire rope to be inspected from other parts, reducing interference from other parts and improving inspection accuracy.

[0033] See Figure 1-2 In this embodiment, there is one positioning mechanism 3, which is located above or below the clamping mechanism 2 and connected to the clamping mechanism 2 in a triangular structure. This design allows for the installation of one or two positioning mechanisms 3 depending on the actual position of the section to be detected on the wire rope 1. If one positioning mechanism 3 is installed, it is located at the upper or lower end of the clamping mechanism 2. The engaging component 6 engages with the wire rope 1, and the two clamping wheels 4 clamp the two sides of the wire rope 1. The ruler 5 and the two anti-loosening components 7 are sequentially connected to the two clamping wheels 4 and the engaging component 6, forming a triangular structure. This improves the connection stability between the clamping mechanism 2 and the positioning mechanism 3, as well as the clamping stability of the wire rope 1.

[0034] See Figure 1-2 In another embodiment, there are two positioning mechanisms 3, mirror-arranged above and below the clamping mechanism 2, and both connected to the clamping mechanism 2 in a triangular structure. This design allows for the selection of one or two positioning mechanisms 3 based on the actual position of the section to be detected on the wire rope 1. If two positioning mechanisms 3 are selected, they are positioned at the upper and lower ends of the clamping mechanism 2. Similarly, the ruler 5, the anti-loosening component 7, the clamping wheel 4, and the engaging component 6 are sequentially connected to form a triangular structure, improving the connection stability between the clamping mechanism 2 and the positioning mechanism 3, as well as the clamping stability of the wire rope 1.

[0035] See Figure 3 In this embodiment, the ruler strip 5 is perpendicular to the steel wire rope 1. One end of the ruler strip 5 is a fixed end 501, and the other end is an open end 502. A groove 503 is provided on the ruler strip 5 along its length direction. The groove 503 communicates with the open end 502. The clamping wheel 4 located on one side of the steel wire rope 1 is fixedly installed with the fixed end 501. The clamping wheel 4 located on the other side of the steel wire rope 1 can slide along the groove 503 through the open end 502 until it abuts against the steel wire rope 1. With this design, one of the clamping wheels 4 is fixedly assembled with the fixed end 501 of the ruler strip 5 and can rotate around the fixed end 501. The ruler strip 5 passes laterally through one or both ends of the section of the steel wire rope 1 to be inspected, so that the clamping wheel 4 is in contact with the steel wire rope 1. The other clamping wheel 4 can pass through the ruler strip 5, slide along the slide groove 503 and approach the clamping wheel 4 located at the fixed end 501 until it presses against the steel wire rope 1. In this way, the steel wire rope 1 is clamped between the two clamping wheels 4 without the need to be fitted from the end of the steel wire rope 1.

[0036] See Figure 4 In this embodiment, the two turntables 8 that abut against both sides of the wire rope 1 can rotate and rise synchronously along the length of the wire rope 1. Each turntable 8 has an annular groove along its circumference and multiple limiting grooves are provided inside. Each toothed piece 901 is fitted and clamped in the turntable 8 and slides and matches each of the limiting grooves one by one. Each toothed piece 901 can slide around the center of the turntable 8 and along the limiting groove, rotate out of the annular groove, until it engages with and locks the wire rope 1. With this design, rotating the turntable 8 can adjust the rotating opening and closing disc 9. When the toothed plate 901 is rotated and retracted into the turntable 8, the two clamping wheels 4 clamp the wire rope 1 relative to each other and can move synchronously along the wire rope 1 to further adjust the specific clamping position. When the toothed plate 901 is rotated and extended out of the turntable 8, the toothed plate 901 and the wire rope 1 are engaged and locked to prevent the clamping wheels 4 from moving and to strengthen the firmness of the clamping mechanism 2 in clamping the wire rope 1.

[0037] The rotary opening and closing disc 9 described in this application may be a standard part or a modified part of a rotary opening and closing device that can be obtained by purchasing in the prior art.

[0038] See Figure 5-6In this embodiment, the engaging assembly 6 includes an outer engaging tube 11, which includes an outer tube 1101 that can be opened and closed along the length of the wire rope 1. There are two outer tubes 1101, both of which are semi-circular arc plate structures. One end of each is elastically hinged by a spring 1102, and the other end is engaged by a toothed opening 1104. Each outer tube 1101 has a handle 1103 fixed on the outer wall of the hinged end for opening or closing the toothed opening 1104. With this design, manually squeezing the handle 1103 can open or close the two outer tube pieces 1101, thereby achieving clamping at any position on the wire rope 1. It can refer to the clamp structure in the prior art, and there is no need to fit it from the end of the wire rope 1, making the operation more flexible and convenient. The two outer tube pieces 1101 abut against each other adopt the toothed mouth 1104 structure, which further improves the tightness of the engagement and prevents the locking component 6 from falling off the wire rope 1.

[0039] See Figure 5-6 In this embodiment, the engaging assembly 6 further includes an inner tube 12 and elastic elements 13. The inner tube 12 is disposed inside the outer tube 1101 and is fixedly connected to the outer tube 1101 via multiple elastic elements 13. The inner tube 12 has a semi-circular arc plate structure, which can fit against and elastically abut against the wire rope 1 along its length. With this design, the inner tube 12 fits against and abuts against the wire rope 1 under the elastic support of the outer tube 1101 and the elastic elements 13, improving the stability of the engaging assembly 6 in clamping the wire rope 1.

[0040] See Figure 5-6 In this embodiment, multiple grooves are spaced apart on the inner wall surface of the inner tube 12, and each groove is fitted with a rolling ball 1201. The rolling ball 1201 can adhere to and slide along the steel wire rope 1. This design reduces the friction between the inner tube 12 and the steel wire rope 1 under the rolling friction of the rolling ball 1201, ensuring that the clamping assembly 6 can smoothly slide along the steel wire rope 1 after stably clamping it, and adjust the specific clamping position.

[0041] See Figure 6In this embodiment, the anti-loosening component 7 includes a T-shaped connector 14 and a connecting piece 15. The T-shaped connector 14 is fixed to the outer wall of the outer clamping tube 11. There are two connecting pieces 15, respectively disposed on both sides of the T-shaped connector 14. One end of each connecting piece 15 is connected to the T-shaped connector 14, and the other end is connected to the center of the front or back of the turntable 8. With this design, the anti-loosening component 7 connects the engaging component 6 and the clamping mechanism 2 through the connecting piece 15, which can improve the connection stability between the clamping mechanism 2 and the positioning mechanism 3, and also improve the clamping stability of the wire rope 1 by constructing a triangular connection structure.

[0042] See Figure 1-3 In this embodiment, the clamping wheel 4 further includes locking components 10. Multiple locking components 10 are detachably installed at the center positions of the front and back sides of the turntable 8. Each locking component 10 includes a washer and a locking bolt. The washer is attached to the ruler strip 5, and the locking bolt passes through the washer and is threaded into the turntable 8 to lock the ruler strip 5, the rotating opening and closing disc 9, and the connecting piece 15. This design allows the device to adopt a detachable installation structure, using only the locking components 10 to fix multiple components, making it simple and easy to operate.

[0043] In summary, in this invention, the clamping mechanism, by sliding and adjusting two clamping wheels arranged side-by-side along the ruler, can clamp the wire rope from any position without needing to fit it from the end of the wire rope. This makes operation flexible and convenient. Furthermore, by rotating and adjusting the rotating opening and closing disc, in the state of the retracted toothed plate, the two clamping wheels clamp the wire rope relative to each other and can move synchronously along the wire rope to further adjust the specific clamping position. In the state of the extended toothed plate, the toothed plate engages and locks with the wire rope, preventing the clamping wheels from moving and strengthening the clamping mechanism's grip on the wire rope. (Positioning machine) This mechanism works in conjunction with a clamping mechanism to clamp and fix the wire rope at the top, bottom, or both ends of the clamping mechanism along its length. It eliminates the need for fitting from the ends of the wire rope, offering flexible and convenient operation. It isolates the section of the wire rope to be inspected from other parts, reducing interference from other parts and improving inspection accuracy. The positioning mechanism is detachably connected to the clamping mechanism. The locking assembly, anti-loosening assembly, clamping wheels, and ruler are located outside the wire rope and connected sequentially to form a triangular structure, further enhancing the firmness of the wire rope clamping.

[0044] It should be understood that the examples and embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various modifications or changes based on them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A clamping and positioning device for use in the detection of defects in a steel wire rope (1), characterized in that: Including clamping mechanism (2) and positioning mechanism (3), the clamping mechanism (2) is clamped horizontally at any part of the steel wire rope (1), and the positioning mechanism (3) is clamped vertically along the length direction of the steel wire rope (1) and is connected with the clamping mechanism (2) at intervals. The clamping mechanism (2) includes clamping wheels (4) and rulers (5), the clamping wheels (4) are two and are distributed side by side on the left and right sides of the steel wire rope (1), and one is fixedly installed with the ruler (5), and the other is slidably installed with the ruler (5), the clamping wheel (4) includes a rotating disc (8) and a rotating opening and closing disc (9), the rotating opening and closing disc (9) is attached to the rotating disc (8), includes a plurality of ring-shaped tooth pieces (901), and each tooth piece (901) has a rotating opening and closing movement stroke of the rotating disc (8); The positioning mechanism (3) includes clamping components (6) and anti-loosening components (7), the clamping components (6) are clamped on the steel wire rope (1) with adjustable tightness, the anti-loosening components (7) are two and are fixed on the left and right sides of the clamping components (6) respectively and are detachably connected with the two clamping wheels (4); The clamping component (6) includes an outer clamping pipe (11), the outer clamping pipe (11) includes an outer pipe piece (1101) which can be clamped along the length direction of the steel wire rope (1), the outer pipe piece (1101) has two and is in a semicircular arc plate structure, and one end is elastically hinged by a spring (1102) and connected, and the other end is closed and occluded by a tooth-shaped opening (1104), and each outer pipe piece (1101) is fixed with a handle (1103) on the outer side wall of the hinged end for opening or closing the tooth-shaped opening (1104); The clamping wheel (4) further includes locking pieces (10), the locking pieces (10) are a plurality of and are detachably installed at the center positions of the front and back of the rotating disc (8), and the locking piece (10) includes a gasket and a locking bolt piece, the gasket is attached to the ruler (5), and the locking bolt piece passes through the gasket and is screwed into the rotating disc (8) for locking the ruler (5), the rotating opening and closing disc (9) and the connecting piece (15).

2. The wire rope flaw detection clamping positioning device according to claim 1, characterized in that: The positioning mechanism (3) has one and is arranged above or below the clamping mechanism (2) and is connected with the clamping mechanism (2) to form a triangular structure.

3. The wire rope inspection clamp positioning device of claim 1, wherein: The positioning mechanism (3) has two and is mirror image arranged above and below the clamping mechanism (2) and is connected with the clamping mechanism (2) to form a triangular structure.

4. The wire rope inspection clamp positioning device of claim 1, wherein: The ruler (5) is vertically distributed with the steel wire rope (1), one end of the ruler (5) is provided as a fixed end (501), the other end is provided as an open end (502), and a sliding groove (503) is provided on the ruler (5) along the length direction, the sliding groove (503) is communicated with the open end (502), the clamping wheel (4) located on one side of the steel wire rope (1) is fixedly installed with the fixed end (501), the clamping wheel (4) located on the other side of the steel wire rope (1) can slide along the sliding groove (503) through the open end (502) until abutting to the steel wire rope (1).

5. The wire rope inspection clamp positioning device of claim 1, wherein: The two rotating discs (8) abutting to the steel wire rope (1) on both sides can synchronously rotate and lift along the length direction of the steel wire rope (1), the rotating disc (8) is provided with a ring groove along the circumference, and a plurality of limiting grooves are annularly arranged inside, the tooth piece (901) is clamped and arranged in the rotating disc (8), and is slidably matched with the limiting groove, and the tooth piece (901) can slide out of the ring groove around the center of the rotating disc (8) and along the limiting groove, until being clamped and locked with the steel wire rope (1).

6. The wire rope inspection clamp positioning device of claim 1, wherein: The clamping assembly (6) further comprises an inner tube piece (12) and an elastic piece (13), the inner tube piece (12) is arranged on the inner side of the outer tube piece (1101) and is fixedly connected with the outer tube piece (1101) through a plurality of elastic pieces (13), and the inner tube piece (12) is a semicircular arc plate structure and can be elastically abutted to the steel wire rope (1) along the length direction.

7. The wire rope inspection clamp positioning device of claim 6, wherein: A plurality of grooves are arranged on the inner wall surface of the inner tube piece (12) at intervals, and a rolling ball (1201) is rollingly embedded in each groove, and the rolling ball (1201) can be abutted and rolled along the steel wire rope (1).

8. The wire rope inspection clamp positioning device of claim 1, wherein: The anti-loose assembly (7) comprises a T-shaped connecting seat (14) and a connecting piece (15), the T-shaped connecting seat (14) is fixed on the outer wall of the outer clamping pipe (11), the connecting piece (15) has two and is arranged on both sides of the T-shaped connecting seat (14), and one end of each connecting piece (15) is connected with the T-shaped connecting seat (14), and the other end is connected with the center of the front or back surface of the rotating disc (8).

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