Pole-mounted transformer gear shifting device

Abstract

The invention relates to the technical field of transformer equipment, and discloses a pole-mounted transformer gear shifting device which comprises a mounting assembly and a clamping assembly. The mounting assembly comprises a first rod body, a commutator and a second rod body, the first rod body extends in the first direction, one end of the first rod body is rotationally connected with one end of the commutator, the second rod body extends in the second direction, one end of the second rod body is rotationally connected with the other end of the commutator, and the first rod body rotates to drive the commutator to rotate; the second rod body is further driven to rotate; the clamping assembly comprises a third rod body, a rotary buckle and a caliper unit used for gear shifting operation, the third rod body is connected with the second rod body, the third rod body is inserted into the second rod body in the second direction, and the rotary buckle is arranged on the outer edge of the second rod body and used for limiting the extending amount of the third rod body in the second direction; the caliper unit is arranged at one end of the third rod body, the second rod body rotates to drive the third rod body to rotate, and the third rod body rotates to drive the caliper unit to rotate.

Description

Technical Field

[0001] The invention relates to the technical field of transformer equipment, and in particular to a pole-mounted transformer gear adjustment device. Background Art

[0002] The gear setting on the transformer is essentially to adjust the voltage through the tap to ensure that the output voltage is stable near the rated value. According to the fluctuation of the input voltage, the output voltage can be maintained within the preset range by changing the wiring method or adjusting the position of the tap. Specifically, the first gear represents a certain percentage increase in the rated voltage, the second gear is the rated voltage, and the third gear is a certain percentage decrease in the rated voltage.

[0003] At present, the traditional gear adjustment method requires workers to climb onto the transformer and manually remove the transformer protective cover to perform the gear adjustment operation, resulting in a high risk factor when workers perform the transformer gear adjustment operation; at the same time, it is time-consuming and laborious for workers to manually remove the transformer protective cover, resulting in a long overall transformer gear adjustment process, which means that during the gear adjustment process, the output voltage will experience a long period of fluctuation, which will have an adverse effect on the user's electrical equipment, resulting in unstable motor speed and flickering lighting, reducing the user's power quality. Based on this, the present invention provides a pole-mounted transformer gear adjustment device to solve the above technical problems. Summary of the invention

[0004] The technical problem to be solved by the present invention is that during the existing transformer gear adjustment operation, workers are required to climb up and manually remove the protective cover, which results in a high risk factor for the gear adjustment operation and a long time consumption for the transformer gear adjustment operation, affecting the user's electricity consumption experience.

[0005] In order to solve the above technical problems, the present invention provides a column-mounted transformer gear shifting device, which includes an installation assembly and a clamping assembly; the installation assembly includes a first rod body, a commutator and a second rod body, the first rod body is extended along a first direction, and one end of the first rod body is rotatably connected to one end of the commutator, the second rod body is extended along a second direction, and one end of the second rod body is rotatably connected to the other end of the commutator, the rotation of the first rod body drives the commutator to rotate, and then drives the second rod body to rotate; the clamping assembly includes a third rod body, a rotating buckle and a caliper unit for gear shifting operation, the third rod body is connected to an end of the second rod body away from the commutator, and the third rod body is inserted into the second rod body along the second direction, the rotating buckle is arranged on the outer edge of the second rod body to limit the extension amount of the third rod body along the second direction, and the caliper unit is arranged at an end of the third rod body away from the second rod body along the second direction; wherein, the rotation of the second rod body drives the third rod body to rotate, and the rotation of the third rod body thereby drives the caliper unit to rotate.

[0006] In one embodiment, the caliper unit includes a base, a first caliper and a second caliper, the base is connected to one end of the third rod body away from the second rod body, the first caliper is arranged at one end of the base, and a telescopic guide rail is arranged at the other end of the base, the second caliper is connected to the base through the telescopic guide rail, and the first caliper and the second caliper both extend along the second direction.

[0007] In one embodiment, the caliper unit also includes a pressure plate buckle, one end of which is connected to the base, and the other end extends through the inner wall of the second caliper to the outside of the second caliper. After the second caliper moves away from the first caliper to a preset position, the pressure plate buckle cooperates with the inner wall of the second caliper to limit the second caliper from approaching the first caliper.

[0008] In one embodiment, the caliper unit further includes an elastic member, which is disposed between the first caliper and the second caliper. When the second caliper gradually moves away from the first caliper, the elastic member applies a force to the second caliper to gradually approach the first caliper, thereby driving the second caliper to rebound to its initial position.

[0009] In one embodiment, the elastic member includes a plurality of torsion springs, one end of each torsion spring is connected to the inner wall of the first caliper, and the other end of each torsion spring is connected to the inner wall of the second caliper.

[0010] In one embodiment, the commutator includes a shell, a first gear and a second gear. A cavity with a top opening is provided inside the shell. The first gear and the second gear are both provided in the cavity. The first gear is connected to the first rod body, the second gear is connected to the second rod body, and the first gear and the second gear are meshed with each other.

[0011] In one embodiment, a plurality of first screw holes are arranged at intervals on the second rod body, a plurality of second screw holes are arranged at intervals on the third rod body, and a spacing between the plurality of first screw holes is the same as a spacing between the plurality of second screw holes.

[0012] In one embodiment, the rotating buckle is arranged on the outer edge of the second rod body, and the rotating buckle includes a threaded rod, which is arranged on the outer edge of the second rod body. When the first screw hole is connected to the second screw hole, one end of the threaded rod is connected to the first screw hole, and the other end is connected to the second screw hole.

[0013] In one embodiment, a connecting seat is provided at one end of the first rod body away from the commutator, and a slot for connecting with a wrench is provided on the connecting seat.

[0014] In one embodiment, a gripping portion is disposed on the outer periphery of the connecting seat for easy gripping by a worker, and an anti-slip pattern is disposed on the outer wall of the gripping portion.

[0015] Compared with the prior art, the pole-mounted transformer gear-adjusting device of the embodiment of the present invention has the following beneficial effects: 1) Clamping assembly: when the staff needs to adjust the gear of the transformer, firstly, by adjusting the length of the third rod, the caliper unit can accurately align and clamp the protective cover of the transformer, and fix the length of the third rod by rotating the buckle; 2) Mounting assembly: by rotating the first rod extending in the first direction, the commutator is driven to rotate, thereby driving the second rod and the third rod extending in the second direction to rotate. Since the third rod is connected to the caliper unit, the caliper unit will also rotate accordingly, thereby realizing the removal operation of the transformer protective cover, so that the staff can rotate the first rod in the first direction to realize the gear-adjusting operation of the transformer in the second direction, and realize the staff remotely operating the transformer gear-adjusting, with a sufficient safety distance, without direct contact with the transformer. The risk factor of the gear-adjusting operation is effectively reduced, and when the first rod is driven to rotate by an external force, the caliper unit is driven to rotate to complete the removal of the protective cover, ensuring that the gear-adjusting operation is less time-consuming, and effectively improving the user's power experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 2 is a front view of an embodiment of the present invention.

[0017] Figure 2 It is a schematic structural diagram of an embodiment of the present invention.

[0018] Figure 3 It is a structural schematic diagram of another angle of an embodiment of the present invention.

[0019] Figure 4 for Figure 3 Enlarged view of part A in the middle.

[0020] Figure 5 is a side view of an embodiment of the present invention.

[0021] Figure 6 for Figure 5 Enlarged view of part B in the middle.

[0022] Figure 7 It is a schematic structural diagram of a caliper unit in an expanded state in an embodiment of the present invention.

[0023] In the figure, 1, mounting assembly; 11, first rod body; 111, connecting seat; 112, holding portion; 12, commutator; 121, housing; 122, first gear; 123, second gear; 13, second rod body; 131, first screw hole;

[0024] 2. Clamping assembly; 21. Third rod body; 211. Second screw hole; 22. Rotating buckle; 23. Caliper unit; 231. Base; 232. First caliper; 233. Second caliper; 234. Pressure plate buckle; 235. Elastic member. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of the present invention, it should be understood that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0027] In the description of the present invention, it should be understood that the terms "height", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] In the description of the present invention, it should be understood that the terms "first" and "second" are used in the present invention for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0029] like Figures 1 to 7As shown, an embodiment of the present invention preferably provides a column-mounted transformer gear-shifting device, which includes a mounting assembly 1 and a clamping assembly 2; the mounting assembly 1 includes a first rod body 11, a commutator 12 and a second rod body 13, the first rod body 11 is extended along a first direction, and one end of the first rod body 11 is rotatably connected to one end of the commutator 12, the second rod body 13 is extended along a second direction, and one end of the second rod body 13 is rotatably connected to the other end of the commutator 12, the first rod body 11 rotates to drive the commutator 12 to rotate, and then drives the second rod body 13 to rotate; the clamping assembly 2 includes a first rod body 11, a commutator 12 and a second rod body 13, the first rod body 11 extends along a first direction, and one end of the first rod body 11 is rotatably connected to the other end of the commutator 12, and the first rod body 11 rotates to drive the commutator 12 to rotate, thereby driving the second rod body 13 to rotate; Three rods 21, a rotating buckle 22 and a caliper unit 23 for gear shifting operations, the third rod 21 is connected to the end of the second rod 13 away from the commutator 12, and the third rod 21 is inserted into the second rod 13 along the second direction, the rotating buckle 22 is arranged on the outer side of the second rod 13 to limit the extension amount of the third rod 21 along the second direction, and the caliper unit 23 is arranged at the end of the third rod 21 away from the second rod 13 along the second direction; wherein, the second rod 13 rotates to drive the third rod 21 to rotate, and the rotation of the third rod 21 further drives the caliper unit 23 to rotate.

[0030] Based on the above technical features, when the staff needs to adjust the gear of the transformer, first adjust the length of the third rod 21 so that the caliper unit 23 can accurately align and clamp the protective cover of the transformer, and fix the length of the third rod 21 by rotating the buckle 22. Then, by rotating the first rod 11 extending in the first direction, the commutator 12 is driven to rotate, thereby driving the second rod 13 and the third rod 21 extending in the second direction to rotate. Since the third rod 21 is connected to the caliper unit 23, the caliper unit 23 will also rotate accordingly, thereby realizing the removal operation of the transformer protective cover, so that the staff can rotate the first rod 11 in the first direction to realize the gear adjustment operation of the transformer in the second direction, and realize the staff remotely operating the transformer gear adjustment, with a sufficient safety distance, without direct contact with the transformer. The risk factor of the gear adjustment operation is effectively reduced. At the same time, when the first rod 11 is driven to rotate by an external force, the caliper unit 23 is driven to rotate to complete the removal of the protective cover, ensuring that the gear adjustment operation takes less time and effectively improving the user's power experience.

[0031] As some embodiments of the present invention, Figure 6 to Figure 7As shown, the caliper unit 23 includes a base 231, a first caliper 232 and a second caliper 233. The base 231 is connected to one end of the third rod body 21 away from the second rod body 13. The first caliper 232 is arranged at one end of the base 231. The other end of the base 231 is provided with a telescopic guide rail. The second caliper 233 is connected to the base 231 through the telescopic guide rail, and the first caliper 232 and the second caliper 233 both extend along the second direction. The caliper unit 23 realizes a stable and flexible clamping function of the caliper unit 23 through the mutual cooperation of the base 231, the first caliper 232, the telescopic guide rail and the second caliper 233. The base 231 is also provided with a telescopic guide rail, which is to allow the second caliper 233 to be able to telescopically move relative to the base 231 when necessary. The staff can adjust the distance between the two calipers according to the diameter of the protective cover that needs to be clamped, so as to clamp protective covers of different sizes and keep the protective cover stable during the clamping process.

[0032] As some embodiments of the present invention, Figure 6 to Figure 7 As shown, the caliper unit 23 also includes a pressure plate buckle 234, one end of which is connected to the base 231, and the other end passes through the inner wall of the second caliper 233 and extends to the outside of the second caliper 233. After the second caliper 233 moves away from the first caliper 232 to a preset position, the pressure plate buckle 234 cooperates with the inner wall of the second caliper 233 to limit the second caliper 233 from approaching the first caliper 232. One end of the pressure plate buckle 234 is closely connected to the base 231 of the caliper unit 23, ensuring the stability and reliability of the buckle. The other end cleverly passes through the inner wall of the second caliper 233 and extends to the outside thereof. This design enables the pressure plate buckle 234 to play a bridge and limit role between the first caliper 232 and the second caliper 233. When the second caliper 233 moves away from the first caliper 232 to a preset position, the other end of the pressure plate buckle 234 cooperates with the inner wall of the second caliper 233. The second caliper 233 is effectively restricted from getting further close to the first caliper 232 , thereby ensuring the stability and safety of the caliper unit 23 at a specific working position.

[0033] As some embodiments of the present invention, Figure 6 to Figure 7As shown, the caliper unit 23 also includes an elastic member 235, which is arranged between the first caliper 232 and the second caliper 233. When the second caliper 233 gradually moves away from the first caliper 232, the elastic member 235 applies a force to the second caliper 233 to make the second caliper 233 gradually approach the first caliper 232, which drives the second caliper 233 to rebound to the initial position. Through the arrangement of the elastic member 235, when the second caliper 233 gradually moves away from the first caliper 232, the elastic member 235 will apply a gradually increasing force to the second caliper 233, and the direction of this force is to make the second caliper 233 gradually approach the first caliper 232. This design enables the second caliper 233 to automatically rebound to its initial position when the external force stops acting, that is, to keep a certain distance or close fit with the first caliper 232. The caliper unit 23 is effectively deployed and reset by the elastic member 235 and the pressure plate buckle 234, and the stability of the caliper unit 23 is further improved.

[0034] As some embodiments of the present invention, Figure 6 As shown, the elastic member 235 includes a plurality of torsion springs, one end of each torsion spring is connected to the inner wall of the first caliper 232, and the other end is connected to the inner wall of the second caliper 233. The function of the torsion spring is to store energy when the second caliper 233 is moved away from the first caliper 232 by an external force, and release the energy after the external force disappears, so as to drive the second caliper 233 to rebound to its initial position or maintain a predetermined distance from the first caliper 232. This rebound and reset ability is an important guarantee for the stable operation of the caliper unit 23. At the same time, the provision of multiple torsion springs further ensures the reset ability of the caliper unit 23.

[0035] As some embodiments of the present invention, Figure 3 to Figure 4 As shown, the commutator 12 includes a housing 121, a first gear 122 and a second gear 123. A cavity with a top opening is provided inside the housing 121. The first gear 122 and the second gear 123 are both provided in the cavity. The first gear 122 is connected to the first rod 11, and the second gear 123 is connected to the second rod 13. The first gear 122 and the second gear 123 are meshed with each other. The first gear 122 is connected to the first rod 11. When the first rod 11 is driven by an external power source to rotate, the first gear 122 will also rotate accordingly. The second gear 123 is meshed with the first gear 122. Therefore, when the first gear 122 rotates, it will drive the second gear 123 to rotate. The second gear 123 is also connected to the second rod 13, thereby transmitting the rotational motion to the second rod 13. At the same time, the cavity in the housing 121 provides the necessary environment and space for the meshing of the first gear 122 and the second gear 123. The design of the top opening facilitates the installation and adjustment of the position of the gears.

[0036] As some embodiments of the present invention, Figure 6 to Figure 7As shown, a plurality of first screw holes 131 are arranged at intervals on the second rod body 13, and a plurality of second screw holes 211 are arranged at intervals on the third rod body 21, and the spacing between the plurality of first screw holes 131 is the same as the spacing between the plurality of second screw holes 211. By inserting fasteners into these screw holes, the two rod bodies can be firmly connected together to form a stable mechanical structure. At the same time, since the spacing between the first screw holes 131 and the second screw holes 211 is the same, the relative position between the second rod body 13 and the third rod body 21 can be adjusted by selecting different screw holes for connection, thereby realizing the adjustment of the length of the third rod body 21.

[0037] As some embodiments of the present invention, Figure 6 to Figure 7 As shown, the rotating buckle 22 is arranged on the outer edge of the second rod body 13, and the rotating buckle 22 includes a threaded rod, which is arranged on the outer edge of the second rod body 13, and when the first screw hole 131 is connected with the second screw hole 211, one end of the threaded rod is connected with the first screw hole 131, and the other end is connected with the second screw hole 211. The arrangement of the first screw hole 131 and the second screw hole 211 facilitates the connection and fixation between the second rod body 13 and the third rod body 21. When the second rod body 13 and the third rod body 21 need to be connected together, first ensure that the first screw hole 131 and the second screw hole 211 are aligned and connected. Then, one end of the threaded rod in the rotating buckle 22 is screwed into the first screw hole 131, and continues to rotate until the other end of the threaded rod can enter and be screwed into the second screw hole 211. Due to the threaded fit between the threaded rod and the screw hole, the stability of the connection between the second rod body 13 and the third rod body 21 is ensured. At the same time, if the relative position between the second rod body 13 and the third rod body 21 needs to be adjusted or the second rod body 13 and the third rod body 21 need to be disassembled, the threaded rod only needs to be rotated in the opposite direction to withdraw it from the first screw hole 131 and the second screw hole 211. This design makes the connection and disassembly process very simple and quick.

[0038] As some embodiments of the present invention, Figure 1 As shown, a connection seat 111 is provided at one end of the first rod body 11 away from the commutator 12, and a slot for connecting with a wrench is provided on the connection seat 111. Through the setting of the connection seat 111, the connection seat 111 serves as an interface between the first rod body 11 and other tools or equipment, and matches with the connector of the electric wrench tool through the slot, thereby achieving a stable connection between the two, and then the rotation of the wrench drives the first rod body 11 to rotate. This connection method is not only simple and fast, but also can withstand a certain torque and tension, ensuring stability and safety during operation.

[0039] As some embodiments of the present invention, Figure 1As shown, the outer periphery of the connection seat 111 is provided with a gripping portion 112 for easy gripping by the staff, and the outer wall of the gripping portion 112 is provided with anti-slip grooves. The gripping portion 112, as a protruding portion on the connection seat 111, provides a clear and easy-to-grip point for the staff. This helps the staff to quickly and accurately grasp the first rod body 11 when needed. At the same time, the provision of the anti-slip grooves is crucial to improving safety during operation, and prevents the first rod body 11 from falling off the hands of the staff.

[0040] In summary, the embodiment of the present invention provides a pole-mounted transformer gear-adjusting device, and its beneficial effects are as follows: 1) Clamping assembly 2, when the staff needs to adjust the gear of the transformer, first adjust the length of the third rod 21 so that the caliper unit 23 can accurately align and clamp the protective cover of the transformer, and fix the length of the third rod 21 by rotating the buckle 22; 2) Installation assembly 1, by rotating the first rod 11 extending in the first direction, drive the commutator 12 to rotate, and then drive the second rod 13 and the third rod 21 extending in the second direction to rotate. Since the third rod 21 is connected to the caliper unit 23, the caliper unit 23 will also rotate accordingly, thereby realizing the removal operation of the transformer protective cover, so that the staff can rotate the first rod 11 in the first direction to realize the gear-adjusting operation of the transformer in the second direction, and realize the staff remotely operate the transformer gear adjustment, with a sufficient safety distance, without direct contact with the transformer. The risk factor of the gear shifting operation is effectively reduced. At the same time, when the first rod body 11 is driven to rotate by an external force, the caliper unit 23 is driven to rotate to complete the removal of the protective cover, ensuring that the gear shifting operation is less time-consuming and effectively improving the user's power consumption experience.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A pole-mounted transformer gear-adjusting device, characterized in that: include: Mounting components and clamping components; The mounting assembly includes a first rod, a commutator, and a second rod. The first rod is extended along the first direction, and one end of the first rod is rotatably connected to one end of the commutator. The second rod is extended along the second direction, and one end of the second rod is rotatably connected to the other end of the commutator. The rotation of the first rod drives the commutator to rotate, thereby driving the second rod to rotate. The clamping assembly includes a third rod, a rotating buckle, and a caliper unit for shifting gears, the third rod is connected to one end of the second rod away from the commutator, and the third rod is inserted into the second rod along the second direction, the rotating buckle is arranged on the outer edge of the second rod to limit the extension amount of the third rod, and the caliper unit is arranged at one end of the third rod away from the second rod along the second direction; The rotation of the second rod drives the third rod to rotate, and the rotation of the third rod further drives the caliper unit to rotate.

2. The pole-mounted transformer gear-adjusting device according to claim 1, characterized in that: The caliper unit includes a base, a first caliper and a second caliper, the base is connected to one end of the third rod body away from the second rod body, the first caliper is arranged at one end of the base, and a telescopic guide rail is arranged at the other end of the base, the second caliper is connected to the base via the telescopic guide rail, and the first caliper and the second caliper both extend along the second direction.

3. The pole-mounted transformer gear-adjusting device according to claim 2, characterized in that: The caliper unit also includes a pressure plate buckle, one end of which is connected to the base, and the other end of which passes through the inner wall of the second caliper and extends to the outside of the second caliper. After the second caliper moves away from the first caliper to a preset position, the pressure plate buckle cooperates with the inner wall of the second caliper to clamp the second caliper to limit the second caliper from approaching the first caliper.

4. The pole-mounted transformer gear-adjusting device according to claim 2, characterized in that: The caliper unit also includes an elastic member, which is arranged between the first caliper and the second caliper. When the second caliper gradually moves away from the first caliper, the elastic member applies a force to the second caliper to make the second caliper gradually approach the first caliper, thereby driving the second caliper to rebound to an initial position.

5. The pole-mounted transformer gear-adjusting device according to claim 4, characterized in that: The elastic member includes a plurality of torsion springs, one end of each torsion spring is connected to the inner wall of the first caliper, and the other end of each torsion spring is connected to the inner wall of the second caliper.

6. The pole-mounted transformer gear-adjusting device according to claim 1, characterized in that: The commutator includes a shell, a first gear and a second gear. A cavity with a top opening is provided inside the shell. The first gear and the second gear are both provided in the cavity. The first gear is connected to the first rod body, and the second gear is connected to the second rod body, and the first gear and the second gear are meshed with each other.

7. The pole-mounted transformer gear-adjusting device according to claim 1, characterized in that: A plurality of first screw holes are arranged at intervals on the outer edge of one end of the second rod body close to the third rod body, and a plurality of second screw holes are arranged at intervals on the outer edge of one end of the third rod body close to the second rod body, and the spacing between the plurality of first screw holes is the same as the spacing between the plurality of second screw holes.

8. The pole-mounted transformer gear-adjusting device according to claim 7, characterized in that: The rotating buckle is arranged on the outer edge of the second rod body, and the rotating buckle includes a threaded rod. The threaded rod is inserted into the first screw hole and the second screw hole. When the first screw hole and the second screw hole are connected to each other, one end of the threaded rod is connected to the first screw hole, and the other end is connected to the second screw hole.

9. The pole-mounted transformer gear-adjusting device according to claim 1, characterized in that: A connecting seat is arranged at one end of the first rod body away from the commutator, and a slot for connecting a wrench is arranged on the connecting seat.

10. The pole-mounted transformer gear-adjusting device according to claim 9, characterized in that: The outer periphery of the connecting seat is provided with a holding portion for the convenience of use by the staff, and the outer wall of the holding portion is provided with anti-slip grooves.

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