Guide rail type transformer substation inspection device

Abstract

The invention relates to the technical field of substation inspection, in particular to a guide rail type substation inspection device which comprises an inspection mechanism for inspecting a substation and a moving mechanism for driving the inspection mechanism to move, an inspection rail is slidably arranged at the upper end of the moving mechanism, and moving racks are symmetrically arranged on the two sides of the lower end of the inspection rail. A double-shaft motor is connected between the gear sets on the two sides in the moving mechanism; a connecting plate is arranged at the lower end of the moving mechanism; a base is arranged at the lower end of the connecting plate; a mounting seat is arranged at the lower end of the base; the inspection mechanism is arranged between the fixing frames on the two sides, fixing bolts are arranged at the upper end of the inspection track, and the inspection track is fixedly arranged on the top of the transformer substation through the fixing bolts. The system has the advantages of being capable of meeting the requirement for all-directional state monitoring of the transformer substation, stable and reliable in operation and low in guide rail maintenance cost.

Description

Technical Field

[0001] The invention relates to the technical field of substation inspection, and in particular to a guide rail type substation inspection device. Background Art

[0002] As substation equipment is in operation for a long time, in order to ensure the safe and stable operation of electrical equipment and to promptly discover equipment defects or hidden dangers, it is necessary to conduct inspections on on-site equipment. However, inspections have problems such as heavy workload, low efficiency, and substandard inspection results. For this purpose, a substation inspection device is provided to achieve remote inspection of substations, effectively solve the problems of missed inspections and false inspections in inspections, and improve the unmanned and automated process of substations. It has been widely used in the field of substations.

[0003] At present, most of the existing rail-type substation inspections use mobile cameras to inspect the substation. Most of them use straight rails for movement, and their effective working range is fixed on a straight line. Therefore, it is impossible to collect data from more directions of the substation environment, and there are still many blind spots. At the same time, a small number of mobile cameras on the market use closed-loop tracks to achieve turning functions, but their structures still have some deficiencies and lack of stability. For example, the images taken during the substation inspection will appear blurred due to the bumps of the machine body, and the video images will be unstable.

[0004] Therefore, in order to solve the above problems, we propose a rail-type substation inspection device. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a rail-type substation inspection device that can meet the needs of all-round status monitoring of substations, has stable and reliable operation, and has low rail maintenance costs, thereby solving the problems raised in the background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a guide rail type substation inspection device, comprising an inspection mechanism for inspecting the substation, and a moving mechanism for driving the inspection mechanism to move, the upper end of the moving mechanism is slidably provided with an inspection track, and both sides of the lower end of the inspection track are symmetrically provided with moving racks, the moving racks are connected to moving wheels, and the moving wheels on both sides are connected to gear sets, and a dual-axis motor is connected inside the moving mechanism between the gear sets on both sides, a connecting plate is provided at the lower end of the moving mechanism, a base is provided at the lower end of the connecting plate, a mounting seat is provided at the lower end of the base, a pan-tilt is connected to the lower end of the mounting seat, and fixed frames are symmetrically provided on both sides of the lower end of the pan-tilt, and the inspection mechanism is arranged between the fixed frames on both sides.

[0007] Preferably, a fixing bolt is provided at the upper end of the inspection track, and the inspection track is fixed to the top of the substation by the fixing bolt.

[0008] Preferably, one end of the inspection track is provided with a first clamping block that is symmetrical left and right and a second clamping block that is symmetrical up and down, and the other side is provided with a first clamping groove and a second clamping groove that are clamped with the first clamping block and the second clamping block, and are fixed by fixing bolts. The inspection track includes a straight track and an arc track. The inspection track combines straight lines and arcs to form a linear track or a closed-loop track suitable for overall inspection of the substation.

[0009] Preferably, baffles are provided on both sides of the moving mechanism, the gear group is arranged in the baffles, the upper gear of the gear group is connected to the moving wheel, the middle gear is arranged in the middle of the inner side of the baffle, and the lower gear is connected to the dual-axis motor. The dual-axis motor drives the moving wheel to make the moving mechanism slide horizontally at the lower end of the inspection track, and drives the inspection mechanism to inspect the substation.

[0010] Preferably, the lower end of the mobile mechanism is fixedly connected to the base via a connecting plate, and a main control module, a battery and a communication module are arranged inside the base.

[0011] Preferably, the main control module is electrically connected to the mounting base, the pan-tilt head, the inspection mechanism and the dual-axis motor respectively, and the main control module realizes communication interaction with the back-end control room through the main control module.

[0012] Preferably, the outside of the base is also electrically connected to an environmental monitoring mechanism and a status indicator light through the main control module. The environmental monitoring mechanism is equipped with various sensors such as temperature and humidity, gas, and smoke, so as to move with the inspection mechanism to monitor the environmental status inside the substation in real time.

[0013] Preferably, the pan-tilt head is fixed to the lower end of the base through a mounting base, a limit block is provided on the inner side of the lower end of the fixing frame symmetrical to the lower end of the pan-tilt head, and limit grooves are provided on both sides of the inspection mechanism corresponding to the limit blocks, and the limit blocks are clamped in the limit grooves.

[0014] Preferably, the inspection mechanism includes a high-definition camera arranged in the middle and infrared thermal imagers arranged on both sides of the high-definition camera, and the infrared thermal imager and the high-definition camera are provided with protective covers at the front ends on the inspection mechanism.

[0015] Preferably, a rotating groove is also provided on the rear side of the inspection mechanism, a rotating block is slidably provided on the inner side of the rotating groove, a rotating member is provided on the upper end of the rotating block, the rotating member is provided in the middle of the lower end of the pan-tilt head, a small motor is provided on the inner side of the lower end of the rotating member, a rotating gear is provided at the lower end of the small motor for transmission in the rotating block, and the rotating gear is in contact with the racks on the inner walls of both sides of the rotating groove.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention forms a linear track or a closed-loop track by splicing a plurality of inspection tracks, so that the inspection mechanism can move on the inspection track to inspect the substation through the moving mechanism, which is conducive to collecting data information from multiple different substation locations through movement, checking the on-site substation equipment and environmental conditions, and through the video images and temperature, humidity, gas, smoke and other environmental information provided by the inspection mechanism and the environmental monitoring mechanism, early detection of whether the on-site substation equipment and environment are abnormal, ensuring the accuracy and reliability of the information, and the present invention can also inspect the substation by itself through the main control module, transmit dynamic information in real time, improve collection efficiency, and reduce labor costs; 2. The present invention achieves the purpose of patrolling the substation while walking by engaging the mobile racks integrally arranged on both sides of the lower end of the inspection track with the mobile wheels arranged on the upper end of the slidingly connected mobile mechanism, and driving the mobile wheels through the dual-axis motor inside the mobile mechanism. At the same time, the mobile racks and the mobile wheels are tightly engaged, which is conducive to the horizontal sliding of the lower end of the inspection track by the mobile mechanism. It can ensure that the images taken during the inspection of the substation will not be bumpy, effectively avoiding blurring, unstable video images, etc., so that the substation can be inspected stably and reliably, greatly improving work efficiency and reducing the cost of manual inspection; 3. The present invention uses the rotating piece in the middle of the lower end of the pan-tilt head and the rotating groove provided on the inspection mechanism. The rotating block at the lower end of the rotating piece inside the rotating groove can drive the rotating gear inside the rotating block to rotate through the small motor inside the rotating piece, so that the rotating block slides in the rotating groove. Through the cooperation of the pan-tilt head, the inspection mechanism can perform all-round video recording around the substation during inspection, improve the monitoring breadth, and realize more directional data collection of the substation environment, thereby avoiding visual blind spots during the substation inspection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the internal structure of the present invention; Figure 3 It is a schematic diagram of the track structure of the present invention; Figure 4 It is a schematic diagram of the fixing bolt structure of the present invention; Figure 5 It is a schematic diagram of the structure of the inspection mechanism of the present invention; Figure 6 It is a schematic diagram of the cross-sectional structure of the rotating mechanism of the present invention.

[0018] Explanations in the figure: 1. Inspection track; 2. Moving mechanism; 3. Base; 4. Mounting seat; 5. Pan / tilt; 6. Fixed frame; 7. Inspection mechanism; 8. Environmental monitoring mechanism; 9. Status indicator light; 10. Connecting plate; 11. Baffle; 12. Fixing bolt; 13. Moving rack; 14. Moving wheel; 15. Gear set; 16. Dual-axis motor; 17. Main control module; 18. Battery; 19. Communication module; 20. Limit block; 21. Infrared thermal imager; 22. High-definition camera; 23. First clamping slot; 24. Second clamping slot; 25. First clamping block; 26. Second clamping block; 27. Rotating member; 28. Rotating slot; 29. ​​Protective cover; 30. Limit slot; 31. Small motor; 32. Rotating block; 33. Rotating gear. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example

[0020] like Figure 1-4 As shown, the present embodiment discloses a guide rail type substation inspection device, comprising an inspection mechanism 7 for inspecting the substation, and a moving mechanism 2 for driving the inspection mechanism 7 to move, an inspection track 1 is slidably arranged on the upper end of the moving mechanism 2, and moving racks 13 are symmetrically arranged on both sides of the lower end of the inspection track 1, the moving racks 13 are connected to moving wheels 14, and the moving wheels 14 on both sides are connected to gear sets 15, and a double-axis motor 16 is connected inside the moving mechanism 2 between the gear sets 15 on both sides, a connecting plate 10 is arranged at the lower end of the moving mechanism 2, a base 3 is arranged at the lower end of the connecting plate 10, a mounting seat 4 is arranged at the lower end of the base 3, a pan-tilt 5 is connected to the lower end of the mounting seat 4, and a fixing frame 6 is symmetrically arranged on both sides of the lower end of the pan-tilt 5, and the inspection mechanism 7 is arranged between the fixing frames 6 on both sides; Among them, a fixing bolt 12 is provided at the upper end of the inspection track 1, and the inspection track 1 is fixedly arranged on the top of the substation by the fixing bolt 12. One end of the inspection track 1 is provided with a left-right symmetrical first clamping block 25 and a top-bottom symmetrical second clamping block 26, and the other side is provided with a first clamping groove 23 and a second clamping groove 24 clamped with the first clamping block 25 and the second clamping block 26, and fixed by the fixing bolt 12; At the same time, baffles 11 are provided on both sides of the mobile mechanism 2, a gear set 15 is provided in the baffle 11, the upper end gear of the gear set 15 is connected to the mobile wheel 14, the middle gear is provided in the middle of the inner side of the baffle 11, and the lower end gear is connected to the double-axis motor 16. The double-axis motor 16 drives the mobile wheel 14 to make the mobile mechanism 2 slide horizontally at the lower end of the inspection track 1, and drives the inspection mechanism 7 to inspect the substation. The lower end of the mobile mechanism 2 is fixedly connected to the base 3 through the connecting plate 10, and the base 3 is provided with a main control Module 17, battery 18 and communication module 19, the main control module 17 is electrically connected to the mounting base 4, the pan / tilt 5, the inspection mechanism 7 and the dual-axis motor 16 respectively, the main control module 17 realizes communication interaction with the back-end control room through the main control module 17, and the outside of the base 3 is also electrically connected to the environmental monitoring mechanism 8 and the status indicator light 9 through the main control module 17. The environmental monitoring mechanism 8 is equipped with various sensors such as temperature and humidity, gas, and smoke, so that it can move with the inspection mechanism 7 and monitor the environmental status in the substation in real time.

[0021] In this embodiment, the dual-axis motor 16 inside the mobile mechanism 2 drives the gear sets 15 on both sides, so that the gear sets 15 drive the moving wheels 14 through gear transmission, and then the moving wheels 14 and the inner racks of the moving racks 13 on both sides of the lower end of the inspection track 1 are used to make the mobile mechanism 2 move horizontally on the inspection track 1, and the base 3 provided at the lower end of the mobile mechanism 2 is used to make the battery 18 provided inside the base 3 provide the required electrical energy for the whole. At the same time, the inspection mechanism 7 is provided on the pan-tilt head 5 at the lower end of the base 3. Through the infrared thermal imager 21 provided on the inspection mechanism 7, the heating phenomenon of the current and voltage of the substation equipment is collected and diagnosed, the temperature trend of the equipment is judged, and the equipment failure is warned. At the same time, the high-definition camera 22 uses high-definition video to patrol and capture the substation equipment. By capturing and identifying the pointer meter readings and the opening and closing and indicator light states on the equipment, remote video monitoring and inspection of the substation equipment are realized, which not only greatly improves the working efficiency, but also verifies the reliability and safety of the substation equipment. Example

[0022] like Figure 1-6As shown, the present embodiment discloses a guide rail type substation inspection device, comprising an inspection mechanism 7 for inspecting the substation, and a moving mechanism 2 for driving the inspection mechanism 7 to move, an inspection track 1 is slidably arranged on the upper end of the moving mechanism 2, and moving racks 13 are symmetrically arranged on both sides of the lower end of the inspection track 1, the moving racks 13 are connected to moving wheels 14, and the moving wheels 14 on both sides are connected to gear sets 15, and a double-axis motor 16 is connected inside the moving mechanism 2 between the gear sets 15 on both sides, a connecting plate 10 is arranged at the lower end of the moving mechanism 2, a base 3 is arranged at the lower end of the connecting plate 10, a mounting seat 4 is arranged at the lower end of the base 3, a pan-tilt 5 is connected to the lower end of the mounting seat 4, and a fixing frame 6 is symmetrically arranged on both sides of the lower end of the pan-tilt 5, and the inspection mechanism 7 is arranged between the fixing frames 6 on both sides; Specifically, a fixing bolt 12 is provided at the upper end of the inspection track 1, and the inspection track 1 is fixedly arranged on the top of the substation by the fixing bolt 12. A left-right symmetrical first clamping block 25 and a top-down symmetrical second clamping block 26 are provided at one end of the inspection track 1, and a first clamping groove 23 and a second clamping groove 24 clamped with the first clamping block 25 and the second clamping block 26 are provided on the other side, and are fixed by the fixing bolt 12. The first clamping block 25 and the second clamping block 26 provided on the left and right sides of the inspection track 1 are connected with the first clamping groove 23 and the second clamping groove 24, so that a plurality of straight and arc inspection tracks 1 are spliced ​​to form a linear track or a closed-loop track, and the fixing bolt 12 provided on the inspection track 1 is arranged on the top of the substation by bolts to patrol and detect the substation; Specifically, baffles 11 are provided on both sides of the mobile mechanism 2, a gear set 15 is provided in the baffle 11, an upper gear of the gear set 15 is connected to the mobile wheel 14, an intermediate gear is provided in the middle of the inner side of the baffle 11, and a lower gear is connected to a double-axis motor 16. The double-axis motor 16 drives the mobile wheel 14 to make the mobile mechanism 2 slide horizontally at the lower end of the inspection track 1, and drives the inspection mechanism 7 to inspect the substation. The lower end of the mobile mechanism 2 is fixedly connected to the base 3 through a connecting plate 10, and a main control module 17, a battery 18 and a pass module are provided inside the base 3. The communication module 19 and the main control module 17 are electrically connected with the mounting base 4, the pan / tilt 5, the inspection mechanism 7 and the dual-axis motor 16 respectively. The main control module 17 realizes communication interaction with the back-end control room through the communication module 19, and is used for the back-end inspection personnel to provide remote inspection means for the inspection department to conduct daily inspections of its substation inspections, so that it can quickly discover, adjust in time, remotely monitor and locate, realize the digitization, intelligence, speed, accuracy and standardization of the inspection process, and fully meet the actual needs of automated substation patrol detection in the information age; Specifically, the outside of the base 3 is also electrically connected to an environmental monitoring mechanism 8 and a status indicator light 9 through a main control module 17. The environmental monitoring mechanism 8 is equipped with a variety of sensors such as temperature and humidity, gas, and smoke, so as to move with the inspection mechanism 7 and monitor the environmental status in the substation in real time, which is used to carry out fire prevention early warning for the substation, so that it can timely collect the fire signal collected by the sensor in the substation, and then transmit the fire signal to the back-end personnel through the communication module 19. After the back-end personnel respond and issue an alarm, they can process the fire signal in time, ensure the warning effect, and improve the overall safety of the substation; Specifically, the pan / tilt 5 is fixed to the lower end of the base 3 through the mounting seat 4, and a limit block 20 is provided on the inner side of the lower end of the fixing frame 6 symmetrical to the lower end of the pan / tilt 5, and limit grooves 30 are provided on both sides of the inspection mechanism 7 corresponding to the limit blocks 20, and the limit blocks 20 are clamped and arranged in the limit grooves 30, so as to clamp and fix the inspection mechanism 7, so that the inspection mechanism 7 can stably inspect the substation; Specifically, the inspection mechanism 7 includes a high-definition camera 22 arranged in the middle and an infrared thermal imager 21 arranged on both sides of the high-definition camera 22. The infrared thermal imager 21 and the high-definition camera 22 are provided with a protective cover 29 on the front end of the inspection mechanism 7. A rotating groove 28 is also provided on the rear side of the inspection mechanism 7. A rotating block 32 is slidably provided inside the rotating groove 28. A rotating member 27 is provided on the upper end of the rotating block 32. The rotating member 27 is arranged in the middle of the lower end of the pan-tilt head 5. A small motor 31 is provided on the inner side of the lower end of the rotating member 27. A rotating gear 33 is provided at the lower end of the small motor 31 in the rotating block 32 for transmission. The rotating gear 33 is fitted with the racks on the inner walls of the rotating groove 28 on both sides, and is used to drive the rotating gear 33 inside the rotating block 32 to slide in the rotating groove 28 provided on the inspection mechanism 7 through the small motor 31 provided inside the rotating member 27, so that the inspection mechanism 7 can perform all-round video recording around the substation, improve the monitoring breadth, and realize more directional inspections of the substation equipment and environment.

[0023] Working principle: When the guide rail substation inspection device is in use, a linear track or a closed-loop track is formed by splicing several straight and arc inspection tracks 1, and the device is installed on the top of the substation, so that the mobile mechanism 2 is slidably arranged at the lower end of the inspection track 1, and the mobile rack 13 arranged on both sides of the lower end of the inspection track 1 is engaged with the mobile wheel 14 arranged at the upper end of the slidingly connected mobile mechanism 2, and the mobile wheel 14 is driven by the internal double-axis motor 16 of the mobile mechanism 2. At the same time, the main control module 17, the battery 18 and the communication module 19 arranged inside the base 3 and the environmental monitoring mechanism 8 and the status indicator light 9 arranged outside are connected to the inspection mechanism 7 through the battery 18 to collect information on the substation equipment, and at the same time, information is transmitted through the communication module 19, so that it can communicate and interact with the back-end control room, and after the back-end personnel respond and issue an alarm, it can achieve rapid discovery, timely adjustment, remote monitoring and positioning processing, realize the digitization, intelligence, rapidity, accuracy and standardization of the inspection process, and provide remote inspection means for the inspection department to conduct daily patrols on its substation inspection situation.

[0024] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0025] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A rail-type substation inspection device, comprising an inspection mechanism (7) for inspecting a substation, and a moving mechanism (2) for driving the inspection mechanism (7) to move, characterized in that: An inspection track (1) is slidably arranged at the upper end of the mobile mechanism (2), and moving racks (13) are symmetrically arranged on both sides of the lower end of the inspection track (1). The moving racks (13) are connected to moving wheels (14), and the moving wheels (14) on both sides are connected to gear sets (15). A dual-axis motor (16) is connected inside the mobile mechanism (2) between the gear sets (15) on both sides. A connecting plate (10) is arranged at the lower end of the mobile mechanism (2), and a base (3) is arranged at the lower end of the connecting plate (10). A mounting seat (4) is arranged at the lower end of the base (3), and a pan-tilt head (5) is connected to the lower end of the mounting seat (4). Fixed frames (6) are symmetrically arranged on both sides of the lower end of the pan-tilt head (5), and the inspection mechanism (7) is arranged between the fixed frames (6) on both sides.

2. A rail-type substation inspection device according to claim 1, characterized in that: A fixing bolt (12) is provided at the upper end of the inspection track (1), and the inspection track (1) is fixedly arranged on the top of the substation by means of the fixing bolt (12).

3. A rail-type substation inspection device according to claim 2, characterized in that: One end of the inspection track (1) is provided with a left-right symmetrical first clamping block (25) and a top-bottom symmetrical second clamping block (26), and the other side is provided with a first clamping groove (23) and a second clamping groove (24) which are clamped with the first clamping block (25) and the second clamping block (26) and are fixed by means of fixing bolts (12).

4. A rail-type substation inspection device according to claim 1, characterized in that: Baffles (11) are provided on both sides of the moving mechanism (2), the gear set (15) is arranged in the baffle (11), the upper gear of the gear set (15) is connected to the moving wheel (14), the middle gear is arranged in the middle of the inner side of the baffle (11), and the lower gear is connected to the double-axis motor (16). The double-axis motor (16) drives the moving wheel (14) to make the moving mechanism (2) slide horizontally at the lower end of the inspection track (1), and drives the inspection mechanism (7) to inspect the substation.

5. The rail-type substation inspection device according to claim 1, characterized in that: The lower end of the mobile mechanism (2) is fixedly connected to the base (3) via a connecting plate (10); a main control module (17), a storage battery (18) and a communication module (19) are arranged inside the base (3).

6. A rail-type substation inspection device according to claim 5, characterized in that: The main control module (17) is electrically connected to the mounting base (4), the pan / tilt platform (5), the inspection mechanism (7) and the dual-axis motor (16) respectively, and the main control module (17) communicates with a back-end control room via the main control module (17).

7. A rail-type substation inspection device according to claim 6, characterized in that: The outside of the base (3) is also electrically connected to an environmental monitoring mechanism (8) and a status indicator light (9) via the main control module (17); the environmental monitoring mechanism (8) is internally equipped with a variety of sensors such as temperature and humidity, gas, and smoke, so as to move along with the inspection mechanism (7) and monitor the environmental status in the substation in real time.

8. A rail-type substation inspection device according to claim 6, characterized in that: The pan / tilt platform (5) is fixed to the lower end of the base (3) via a mounting seat (4); a limit block (20) is provided on the inner side of the lower end of the fixing frame (6) symmetrical to the lower end of the pan / tilt platform (5); limit grooves (30) are provided on both sides of the inspection mechanism (7) corresponding to the limit blocks (20); and the limit blocks (20) are clamped and arranged in the limit grooves (30).

9. A rail-type substation inspection device according to claim 6, characterized in that: The inspection mechanism (7) comprises a high-definition camera (22) arranged in the middle and infrared thermal imagers (21) arranged on both sides of the high-definition camera (22), and the infrared thermal imager (21) and the high-definition camera (22) are provided with protective covers (29) at the front ends on the inspection mechanism (7).

10. A rail-type substation inspection device according to claim 9, characterized in that: The inspection mechanism (7) is further provided with a rotating groove (28) at the rear side, a rotating block (32) is slidably provided inside the rotating groove (28), a rotating member (27) is provided at the upper end of the rotating block (32), the rotating member (27) is arranged in the middle of the lower end of the pan-tilt platform (5), a small motor (31) is provided inside the lower end of the rotating member (27), a rotating gear (33) is provided at the lower end of the small motor (31) in the rotating block (32), and the rotating gear (33) is in contact with the racks on the inner walls of both sides of the rotating groove (28).

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