A coal mine drilling vehicle

Abstract

The present application relates to the technical field of drilling rig, and proposes a drilling rig for coal mining, which comprises: a drill rod arranged on a drilling rig body; a drill bit arranged on the drill rod; a moving driving element arranged on the drill rod; and a plurality of protective plates arranged on the moving driving element and spaced along the circumference of the drill rod, the moving driving element being used to drive the protective plates to move closer to or further away from the drill rod. The above technical solution solves the problem that the drill rod cannot be taken out after collapse occurs during the drilling process in the prior art.

Description

Technical Field

[0001] This invention relates to the field of drilling vehicle technology, specifically to a drilling vehicle used in coal mining. Background Technology

[0002] A drilling rig is an engineering vehicle used to drill through strata and obtain geological data. Drilling rigs are widely used in geological exploration, mineral resource development, and foundation construction, playing a crucial role in obtaining underground information, understanding geological structures, assessing resource reserves, and guiding engineering construction. In coal mining, drilling rigs are widely used for drilling operations during the coal mining process.

[0003] Existing coal mine drilling rigs typically drill drill rods into rock or soil layers. However, these layers can collapse, trapping the drill rod underneath and preventing it from rotating. This can result in the drill rod being impossible to retrieve, leading to significant economic waste. Summary of the Invention

[0004] This invention proposes a drilling vehicle for coal mine development, which solves the problem of drill rods being unable to be removed after a collapse during drilling in related technologies.

[0005] The technical solution of the present invention is as follows: A drilling rig used in coal mining includes: Drilling vehicle body; Drill pipe, mounted on the drilling vehicle body; The drill bit is mounted on the drill rod; A movable drive component is mounted on the drill pipe; A protective plate is disposed on the moving drive component. There are several protective plates, which are spaced apart along the circumference of the drill rod. The moving drive component is used to move the protective plates closer to or away from the drill rod.

[0006] Optionally, the moving drive includes: A support member is provided on the drill pipe; A sliding disk is slidably disposed on the drill rod along the axis of the drill rod, and a protective plate is slidably disposed on the sliding disk, with the sliding direction of the protective plate being the radial direction of the drill rod; A wedge is slidably disposed on the sliding disk. After sliding, the wedge abuts against the protective plate and drives the protective plate away from the drill pipe. The first elastic element has its two ends respectively disposed on the sliding disk and the support element.

[0007] Also includes: A first lever is mounted on the support member and passes through the sliding disc. The first lever has two parts, which are respectively disposed at both ends of the sliding disk. After the sliding disk slides, the wedge abuts against the first lever.

[0008] Optionally, there are two of each of the sliding disk, the wedge, the first elastic element, and the first lever, which are distributed on both sides of the support member. There are two sets of protective plates, which are slidably disposed on the two sliding disks respectively. The two sets of protective plates form a protective space, and the drill rod is located in the protective space. The two first elastic elements are used to provide tension and pressure respectively.

[0009] Optionally, the wedges are in two sets, located on both sides of the sliding disk, and further include: The device includes two connecting rings, which are located on both sides of the sliding disk. Two sets of wedges are respectively disposed on the two connecting rings. After the connecting rings are moved, they abut against the first lever block. A connecting rod is slidably mounted on the sliding disk and passes through the sliding disk, with both ends of the connecting rod connected to the two connecting rings.

[0010] Optional, also includes: The second elastic element has its two ends respectively disposed between the protective plate and the sliding disk. The second elastic element is used to provide the protective plate with a force close to the drill rod.

[0011] Optionally, the support member includes: A fixing element is provided on the drill rod; the fixing element has a first protrusion. A sliding cylinder is sleeved on the drill rod. The sliding cylinder and the drill rod are connected by a sliding bearing. The fixing member is located between the sliding cylinder and the drill rod. The inner wall of the sliding cylinder has a second protrusion. After the fixing member moves and rotates, the second protrusion abuts against the first protrusion, and the sliding cylinder rotates. The outer wall of the sliding cylinder has threads. An adjusting element is threaded onto the sliding cylinder.

[0012] Optional, also includes: A second lever is disposed on the sliding disk, and the second lever passes through the support member and another sliding disk; The second lever has two blocks, which are disposed on the second lever, with the two second levers located on either side of the other sliding disk.

[0013] Optional, also includes: A tie rod is mounted on the drilling vehicle body; A hinge rod is hinged to the tie rod. After the drill rod is installed on the drilling rig, the hinge rod hooks onto the nearest protective plate. The reset element is located at both ends on the pull rod and the hinge rod.

[0014] Optionally, the protective plate includes: A sliding block is slidably mounted on the sliding disk; There are several protective strips, which are spaced apart on the sliding block.

[0015] The working principle and beneficial effects of this invention are as follows: In this invention, when the drilling rig is performing drilling operations, it needs to install drill rods and drill bits. During drill rod installation, the moving drive unit and protective plates are first installed onto the drill rod, and then the drill rod is installed onto the drilling rig body. Multiple protective plates are spaced circumferentially, providing all-around protection for the drill rod. As the drill rod advances, the moving drive unit can move the protective plates closer to or further away from the drill rod, creating a contraction-opening process that compacts the inner wall of the borehole, preventing collapse of soft soil and coal seams. This also avoids interference between the protective plates and the borehole wall when the drill rod moves forward, ensuring that the drill rod can advance while still being protected. In the event of a collapse and the need to remove the drill rod, the protective plates will also move closer to or further away from the drill rod, dispersing debris, soil, or coal seams, thus ensuring the drill rod can be easily removed. Attached Figure Description

[0016] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of the present invention.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the drill rod and support structure of the present invention; Figure 3 This is an exploded view of the support component of the present invention; Figure 4 This is a cross-sectional view of the sliding disk of the present invention; Figure 5 This is a schematic diagram of the support structure of the present invention; Figure 6 for Figure 4 Enlarged view at point B in the middle; Figure 7 This is a schematic diagram of the connecting ring structure of the present invention; Figure 8 This is a schematic diagram of the sliding disk structure of the present invention; Figure 9 This is a schematic diagram of the sliding cylinder structure of the present invention; Figure 10 This is a schematic diagram of the protective plate structure of the present invention; Figure 11 for Figure 1 Enlarged view of point A in the middle; Figure 12 This is a schematic diagram of the structure of the present invention with the protective component removed; Figure 13 for Figure 12 Enlarged view at point C; In the diagram: 1. Drilling vehicle body, 2. Drill rod, 3. Drill bit, 4. Moving drive component, 5. Protective plate, 401. Support component, 402. Sliding disc, 403. Wedge block, 404. First elastic component, 405. First lever, 406. First lever block, 6. Connecting ring, 7. Connecting rod, 501. Second elastic component, 4011. Fixing component, 4012. First protrusion, 4013. Sliding cylinder, 4014. Second protrusion, 4015. Adjusting component, 407. Second lever, 408. Second lever block, 8. Pull rod, 9. Hinge rod, 10. Reset component, 502. Sliding block, 503. Protective strip. Detailed Implementation

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0019] To keep the drawings concise, each drawing only schematically shows the parts relevant to the invention; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0020] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Example 1 Reference Figures 1-2 As the first embodiment of the present invention, a drilling vehicle for coal mining is proposed, comprising: a drill rod 2 disposed on the drilling vehicle body 1; a drill bit 3 disposed on the drill rod 2; a moving drive component 4 disposed on the drill rod 2; and a protective plate 5 disposed on the moving drive component 4. The protective plate 5 has a plurality of plates, which are spaced apart along the circumference of the drill rod 2. The moving drive component 4 is used to drive the protective plate 5 to move closer to or away from the drill rod 2.

[0023] In this embodiment, when the drilling vehicle is performing drilling operations, it needs to install drill rod 2 and drill bit 3. When installing drill rod 2, the moving drive component 4 and protective plate 5 are first installed onto drill rod 2, and then drill rod 2 is installed onto the drilling vehicle body 1. Multiple protective plates 5 are arranged at circumferential intervals, providing all-around protection for drill rod 2. Furthermore, as drill rod 2 moves forward, the moving drive component 4 can drive the protective plates 5 closer to or further away from drill rod 2. This creates a process similar to contraction and expansion of the protective plates 5, which can compress and compact the inner wall of the borehole, preventing the collapse of soft soil and coal seams. It also avoids interference between the protective plates 5 and the borehole wall when drill rod 2 moves forward, ensuring that the drill rod 2 can move forward while being protected. When a collapse occurs and drill rod 2 needs to be withdrawn, the protective plates 5 will also move closer to or further away from drill rod 2, thereby squeezing out gravel, soil, or coal seams, ensuring the smooth withdrawal of drill rod 2.

[0024] Optionally, the moving drive component 4 includes: a support component 401 disposed on the drill rod 2; a sliding disk 402 slidably disposed on the drill rod 2 along the axial direction of the drill rod 2; a protective plate 5 slidably disposed on the sliding disk 402, the sliding direction of the protective plate 5 being the radial direction of the drill rod 2; a wedge block 403 slidably disposed on the sliding disk 402, the wedge block 403 abutting against the protective plate 5 after sliding and driving the protective plate 5 away from the drill rod 2; and a first elastic component 404 with its two ends disposed on the sliding disk 402 and the support component 401, respectively.

[0025] In this embodiment, a driving method for the moving drive component 4 is described: When the drill rod 2 moves forward or backward, the support component 401 drives the first elastic component 404 to move, which in turn drives the wedge block 403 to move. When the wedge block 403 moves, it can squeeze the protective plate 5, thereby moving the protective plate 5 away from the drill rod 2, and the protective plate 5 will abut against the borehole wall. When the first elastic component 404 continues to move, it will provide a force in the opposite direction to the wedge block 403, thereby gradually reducing the force between the wedge block 403 and the protective plate 5. Under the action of the reaction force of the borehole wall and its own gravity, the protective plate 5 will move closer to the drill rod 2, and the protective plate 5 will detach from the borehole wall. Because the protective plate 5 moves rapidly after detaching from the borehole wall, it first moves along the direction of the elastic force of the first elastic element 404, which extends or shortens. Then, the force provided by the first elastic element 404 changes direction. At this time, the sliding disk 402 continues to move under inertia, but the wedge block 403 moves in the opposite direction to the sliding disk 402. Therefore, the wedge block 403 will abut against the protective plate 5 again, causing the protective plate 5 to move away from the drill rod 2 and abut against the borehole wall. This cycle repeats, allowing the protective plate 5 to move inside the borehole.

[0026] Example 2, Reference Figures 1-13 This is the second embodiment of the present invention, which differs from the first embodiment in that: It also includes: a first lever 405 is mounted on the support member 401, and the first lever 405 passes through the sliding disk 402; there are two first blocks 406, which are respectively mounted at both ends of the sliding disk 402, and the wedge block 403 abuts against the first block 406 after the sliding disk 402 slides.

[0027] In this embodiment, to better achieve the movement of the protective plate 5, a first elastic element 404 is disposed on the sliding disk 402, and a lever is disposed on the support member 401. When the sliding disk 402 slides, the first lever 406 abuts against the wedge block 403 and drives the wedge block 403 to move. By setting the position of the first lever 406, the first lever 406 abuts against the wedge block 403 when the elastic force of the first elastic element 404 is at its maximum, making the wedge block 403 move faster and more sensitively.

[0028] Example 3, Reference Figures 1-2 This is the third embodiment of the present invention, which differs from the first and second embodiments in that: There are two sliding discs 402, two wedges 403, two first elastic elements 404 and two first levers 405, which are distributed on both sides of the support 401. There are two sets of protective plates 5, which are slidably mounted on the two sliding discs 402 respectively. The two sets of protective plates 5 form a protective space. The drill rod 2 is located in the protective space. The two first elastic elements 404 are used to provide tension and pressure respectively.

[0029] In this embodiment, the two sets of sliding discs 402, wedges 403, first elastic elements 404, and first levers 405 can achieve alternating operation of the two sets of protective plates 5 by adjusting the force state of the two first elastic elements 404 at the same time. This achieves a step-like forward movement, and one set of protective plates 5 is always in contact with the borehole wall to prevent collapsing material from burying the drill rod 2. Specifically, by adjusting the state of the two first elastic elements 404 at the same time, one first elastic element 404 is under tension and the other is under pressure. When the first elastic element 404 under tension pulls the sliding disc 402 to move, the sliding disc 402 connected to the first elastic element 404 under pressure remains stationary, and the protective element on the sliding disc 402 is in contact with the borehole wall. When the sliding disc 402 on the first elastic element 404 under tension remains stationary, the protective element on it is in contact with the borehole wall. At this time, the other set of protective plates 5 leaves the borehole wall, and the first elastic element 404 under pressure pushes the sliding disc 402 to move, and this cycle repeats continuously.

[0030] Optionally, the wedge block 403 has two sets, located on both sides of the sliding disk 402 respectively, and also includes: two connecting rings 6, located on both sides of the sliding disk 402 respectively, the two sets of wedge blocks 403 are respectively disposed on the two connecting rings 6, and the connecting rings 6 abut against the first lever block 406 after moving; the connecting rod 7 is slidably disposed on the sliding disk 402 and passes through the sliding disk 402, and the two ends of the connecting rod 7 are connected to the two connecting rings 6.

[0031] In this embodiment, to ensure the protective plate 5 provides protection during both entry and exit of the drill rod 2 into the borehole, two sets of wedges 403 are respectively mounted on two connecting rings 6. The two connecting rings 6 are fixedly connected and slidably positioned relative to the sliding disk 402. When the drill rod 2 enters the borehole, the connecting ring 6 abuts against one of the first deflectors 406, and both connecting rings 6 move in one direction simultaneously. At this time, only one wedge 403 abuts against the protective plate 5. When the other first deflector 406 abuts against the connecting ring 6, the previously abutting wedge 403 moves in the opposite direction, thus moving away from the protective plate 5. The drill rod 2 continues to advance into the borehole, with only one set of wedges 403 abutting against the protective plate 5. When the drill rod 2 moves in another direction, the two sets of protective plates 5 on the drill rod 2 mirror each other. The wedges 403 that were not previously in contact with the protective plate 5 at the same position will abut against the protective plate 5, while the previously contacting wedges 403 will no longer abut.

[0032] Optionally, it also includes: the two ends of the second elastic member 501 are respectively disposed between the protective plate 5 and the sliding disk 402, and the second elastic member 501 is used to provide the force of the protective plate 5 close to the drill rod 2.

[0033] In this embodiment, in order to make the protective plate 5 move better toward the drill rod 2, a second elastic member 501 is provided between the protective plate 5 and the sliding disk 402. The second elastic member 501 provides a force for the protective plate 5 to move closer to the drill rod 2, thus preventing the protective plate 5 from being unable to leave the borehole wall.

[0034] Optionally, the support member 401 includes: a fixing member 4011 disposed on the drill rod 2; the fixing member 4011 having a first protrusion 4012; a sliding cylinder 4013 sleeved on the drill rod 2, the sliding cylinder 4013 and the drill rod 2 being connected by a sliding bearing, the fixing member 4011 being located between the sliding cylinder 4013 and the drill rod 2, the inner wall of the sliding cylinder 4013 having a second protrusion 4014, after the fixing member 4011 moves and rotates, the second protrusion 4014 abuts against the first protrusion 4012, the sliding cylinder 4013 rotating, the outer wall of the sliding cylinder 4013 having threads; and an adjusting member 4015 threadedly connected to the sliding cylinder 4013.

[0035] In this embodiment, when the drill rod 2 moves in the opposite direction, the actions of the two sets of protective plates 5 will be mirrored and reversed, so the position of the first lever 406 also needs to be changed: when the drill rod 2 enters the borehole, the position of the first lever 406 is adjusted first. At this time, the fixing member 4011 will abut against the sliding cylinder 4013, and the first protrusion 4012 and the second protrusion 4014 will not abut against each other. At this time, the sliding cylinder 4013 will rotate relative to the drill rod 2, and the fixing member 4011, the sliding cylinder 4013 and the drill rod 2 will advance into the borehole at the same time. When drill rod 2 needs to be withdrawn from the borehole, drill rod 2 drives the fixing member 4011 to move in the opposite direction. The fixing member 4011 and drill rod 2 rotate and slide relative to the sliding cylinder 4013. When the first protrusion 4012 abuts against the second protrusion 4014, it will drive the sliding cylinder 4013 to rotate. At this time, there is no axial relative movement between drill rod 2, fixing member 4011 and sliding cylinder 4013. Adjusting member 4015 will move under the action of the thread, thereby changing the position of the first lever 406. During the movement of adjusting member 4015, the first lever 406 will abut against different connecting rings 6, thereby causing the two sets of protective plates 5 to switch. After the switch is completed, due to the action of the first elastic member 404, adjusting member 4015 no longer moves, but the sliding cylinder 4013 is still rotating. The sliding cylinder 4013 will form relative sliding with the fixing member 4011, thereby causing the first protrusion 4012 and the second protrusion 4014 to disengage. The sliding cylinder 4013 stops rotating, completing the switching of the protective plate 5. The magnitude of the force between the adjusting member 4015 and the first elastic member 404 can be obtained by those skilled in the art through experiments.

[0036] Optionally, it also includes: a second lever 407 disposed on a sliding disk 402, the second lever 407 passing through a support 401 and another sliding disk 402; and two second blocks 408 disposed on the second lever 407, the two second blocks 408 being located on opposite sides of another sliding disk 402.

[0037] In this embodiment, in order to better realize the linkage of the two sets of protective plates 5, a second lever 407 is provided on the two sliding disks 402; the two second levers 407 pass through the other sliding disk 402 respectively, and the second lever 408 is located at the two sides of the sliding disk 402. One set of protective plates 5 abuts against the borehole wall for support. When one sliding disk 402 slides, when the wedge 403 on the sliding sliding disk 402 abuts against the first lever 406, the second lever 408 on the sliding sliding disk 402 will bring the supported protective plate 5 closer to the drill rod 2, thereby realizing the linkage.

[0038] Optionally, it also includes: a tie rod 8 is mounted on the drilling vehicle body 1; a hinge rod 9 is hinged on the tie rod 8, and after the drill rod 2 is installed on the drilling vehicle, the hinge rod 9 hooks onto the nearest protective plate 5; and the reset piece 10 is mounted on the tie rod 8 and the hinge rod 9 at both ends.

[0039] In this embodiment, in order to enable the protective plates 5 to perform alternating actions when the drill rod 2 enters the borehole: as the drill rod 2 gradually enters the borehole, the hinge rod 9 hooks onto a set of protective plates 5, thereby causing the first elastic element 404 to deform. The second lever 408 on the second lever 407 corresponding to this protective plate 5 will cause another set of protective plates 5 to move away from the drill rod 2. When the force between the protective plate 5 and the hinge rod 9 is greater than the force of the reset element 10, the hinge rod 9 rotates and the sliding disk 402 slides, thereby realizing the starting force for the alternating action of the protective plates 5.

[0040] Optionally, the protective plate 5 includes: a sliding block 502 slidably disposed on the sliding disk 402; and a plurality of protective strips 503 disposed at intervals on the sliding block 502.

[0041] In this embodiment, in order to reduce the weight of the protective plate 5, multiple protective strips 503 are arranged on the sliding block 502, and the multiple protective plates 5 form a cage-like structure, which can achieve the protection function and reduce the weight.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A drilling rig for coal mining, characterized in that, include: Drilling vehicle body (1); Drill rod (2) is mounted on the drilling vehicle body (1); The drill bit (3) is mounted on the drill rod (2); A movable drive unit (4) is mounted on the drill rod (2); A protective plate (5) is provided on the moving drive (4). There are several protective plates (5) and they are spaced apart along the circumference of the drill rod (2). The moving drive (4) is used to drive the protective plate (5) to move closer to or away from the drill rod (2). The moving drive (4) includes: A support member (401) is provided on the drill rod (2); A sliding disk (402) is slidably disposed on the drill rod (2) along the axial direction of the drill rod (2), and a protective plate (5) is slidably disposed on the sliding disk (402). The sliding direction of the protective plate (5) is the radial direction of the drill rod (2). A wedge (403) is slidably disposed on the sliding disk (402). After the wedge (403) slides, it abuts against the protective plate (5) and drives the protective plate (5) away from the drill rod (2). The first elastic element (404) has its two ends respectively disposed on the sliding disk (402) and the support element (401); Also includes: A first lever (405) is disposed on the support (401) and passes through the sliding disk (402). Two first paddle blocks (406) are respectively disposed at both ends of the sliding disk (402). After the sliding disk (402) slides, the wedge block (403) abuts against the first paddle block (406). Two of each of the sliding disk (402), the wedge (403), the first elastic element (404), and the first lever (405) are distributed on both sides of the support (401). Two sets of protective plates (5) are provided, and the two sets of protective plates (5) are slidably disposed on the two sliding disks (402). The two sets of protective plates (5) form a protective space. The drill rod (2) is located in the protective space. The two first elastic elements (404) are used to provide tension and pressure respectively. The wedge (403) has two sets, located on both sides of the sliding disk (402); There are two connecting rings (6), which are located on both sides of the sliding disk (402). Two sets of wedges (403) are respectively disposed on the two connecting rings (6). After the connecting rings (6) move, they abut against the first lever (406). The connecting rod (7) is slidably disposed on the sliding disk (402) and passes through the sliding disk (402). Both ends of the connecting rod (7) are connected to the two connecting rings (6).

2. A drilling rig for coal mining according to claim 1, characterized in that, Also includes: The second elastic element (501) is disposed at both ends between the protective plate (5) and the sliding disk (402). The second elastic element (501) is used to provide the protective plate (5) with force close to the drill rod (2).

3. A drilling rig for coal mine development according to claim 1, characterized in that, The support member (401) includes: A fastener (4011) is provided on the drill rod (2); the fastener (4011) has a first protrusion (4012). A sliding cylinder (4013) is sleeved on the drill rod (2). The sliding cylinder (4013) and the drill rod (2) are connected by a sliding bearing. The fixing member (4011) is located between the sliding cylinder (4013) and the drill rod (2). The inner wall of the sliding cylinder (4013) has a second protrusion (4014). After the fixing member (4011) moves and rotates, the second protrusion (4014) abuts against the first protrusion (4012). The sliding cylinder (4013) rotates. The outer wall of the sliding cylinder (4013) has threads. Adjusting element (4015) is threaded onto the sliding cylinder (4013).

4. A drilling rig for coal mining according to claim 3, characterized in that, Also includes: A second lever (407) is disposed on the sliding disk (402), and the second lever (407) passes through the support (401) and the other sliding disk (402). There are two second levers (408), which are disposed on the second lever (407), and the two second levers (408) are respectively located on both sides of the other sliding disk (402).

5. A drilling rig for coal mine development according to claim 1, characterized in that, Also includes: A tie rod (8) is mounted on the drilling vehicle body (1); The hinge rod (9) is hinged on the pull rod (8). After the drill rod (2) is installed on the drilling rig, the hinge rod (9) hooks onto the nearest protective plate (5). The reset component (10) is disposed at both ends on the pull rod (8) and the hinge rod (9).

6. A drilling rig for coal mining according to claim 1, characterized in that, The protective plate (5) includes: A sliding block (502) is slidably disposed on the sliding disk (402); The protective strip (503) has several pieces, which are spaced apart on the sliding block (502).

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