A concrete mixing device for making track slab
Patent Information
- Application Number
- CN202521900619.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-04
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2035-09-04
AI Technical Summary
这些结块不仅会占据有效搅拌空间，导致实际搅拌容量下降，还会阻碍混凝土混合料的充分流动与翻滚，使得部分物料长期滞留于内壁附近，无法参与均匀混合
1、本实用新型通过与传统装置相比，该装置通过在搅拌效率方面，电机带动第二旋转轴，经传动皮带使第一旋转轴协同转动，第一旋转轴的螺旋叶片快速均匀输送分流箱原料至搅拌罐，避免堆积、缩短投料时间；第二旋转轴的搅拌杆同步搅拌，多部件配合让原料快速充分混合，满足大规模生产需求，搅拌质量上，第二旋转轴转动时，连接杆带动刮板贴合罐壁转动，及时刮除附着原料，确保搅拌均匀，且合理设计使水与原料充分融合，制作出的混凝土质量稳定，符合轨道板对强度、耐久性的严苛要求，操作上，工作人员按投料、启动电机、注水等简单顺序操作即可，流程清晰易掌握，降低操作难度与劳动强度，同时，规范流程和装置稳定运行减少了安全事故风险，保障了工作人员人身安全。
Smart Images
Figure CN224897641U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of concrete mixing technology, and more specifically, to a concrete mixing device for manufacturing track slabs. Background Technology
[0002] Concrete mixing equipment for track slab production is a specialized piece of machinery designed for the efficient and uniform mixing of concrete raw materials during track slab production. A prominent issue in existing concrete mixing equipment is the adhesion of concrete lumps to the inner wall of the mixing drum, which has become a key factor affecting mixing quality. Due to surface characteristics or structural design defects in the inner wall material, cement, aggregates, and other components in the concrete easily adhere to the inner wall during high-speed rotation, forming a stubborn lumpy layer. These lumps not only occupy effective mixing space, reducing the actual mixing capacity, but also hinder the full flow and tumbling of the concrete mixture, causing some materials to remain near the inner wall for extended periods, unable to participate in uniform mixing. As mixing time increases, the adhesion phenomenon intensifies, resulting in uneven distribution of concrete components, with localized areas of excessively high or low cement content, ultimately leading to substandard strength, durability, and other performance indicators of the concrete. Furthermore, the detachment of lumps from the inner wall introduces impurities, further deteriorating the concrete quality. Summary of the Invention
[0003] In order to overcome the shortcomings of the existing technology, this utility model provides a concrete mixing device for manufacturing track slabs, which has the advantage of high concrete mixing efficiency.
[0004] To achieve the above objectives, the present invention provides the following technical solution: a concrete mixing device for making track slabs, comprising a support platform, a mixing tank fixedly installed on the top of the support platform, a second rotating shaft movably installed inside the mixing tank, a connecting rod movably installed on the outer surface of the second rotating shaft, a scraper fixedly installed at one end of the connecting rod, and the outer side of the scraper adhering to the inside of the mixing tank, and a mixing rod fixedly installed on the outer surface of the second rotating shaft; A diversion box is fixedly installed on the top of the mixing tank, and a feed pipe is fixedly installed on the top of the diversion box. A driven gear is fixedly installed at one end of the second rotating shaft. A first rotating shaft is movably installed inside the diversion box. A drive wheel is fixedly installed at one end of the first rotating shaft, and a drive belt is connected to the drive wheel. Spiral blades are fixedly installed on the outer surface of the first rotating shaft. A motor is fixedly installed on the left side of the mixing tank, and the output end of the motor is fixedly connected to the second rotating shaft. A water inlet pipe is fixedly installed on the left side of the mixing tank.
[0005] As a preferred embodiment of this utility model, a limiting plate is fixedly installed at the bottom of the support platform, a fixing rod is movably installed inside the limiting plate, a collection box is hinged to the front of the fixing rod, columns are fixedly installed around the bottom of the collection box, a one-way valve is fixedly installed inside the mixing tank, casters are hinged to the bottom of the columns, a push rod is fixedly installed on the front of the collection box, a rotating block is fixedly installed on the back of the fixing rod, and a discharge pipe is fixedly installed at the bottom of the support platform.
[0006] As a preferred embodiment of this utility model, a support plate is fixedly installed at the bottom of the support platform, and a connecting plate is fixedly installed between the two support plates.
[0007] As a preferred embodiment of this utility model, a reinforcing rib is fixedly installed at the angle between the connecting plate and the supporting plate, and the reinforcing rib is triangular in shape.
[0008] As a preferred embodiment of this utility model, a fixed base is fixedly installed on the front of the support platform, a fixed block is movably installed inside the fixed base, and a working box is fixedly installed on the front of the fixed block.
[0009] As a preferred embodiment of this utility model, a support base is fixedly installed on the left side of the mixing tank, and the interior of the support base is in the form of a U-shaped groove.
[0010] As a preferred embodiment of this utility model, the connecting rod and the scraper are arranged in pairs, with a total of three sets on the outer surface of the second rotating shaft.
[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Compared with traditional devices, this utility model improves mixing efficiency by having a motor drive a second rotating shaft, which in turn drives a first rotating shaft via a transmission belt. The spiral blades of the first rotating shaft quickly and evenly transport raw materials from the distribution box to the mixing tank, avoiding accumulation and shortening the feeding time. The stirring rod of the second rotating shaft stirs synchronously, and the cooperation of multiple components ensures rapid and thorough mixing of raw materials, meeting the needs of large-scale production. In terms of mixing quality, when the second rotating shaft rotates, the connecting rod drives the scraper to rotate against the tank wall, promptly scraping off adhering raw materials and ensuring uniform mixing. Furthermore, the reasonable design ensures that water and raw materials are fully integrated, resulting in stable concrete quality that meets the stringent requirements for strength and durability of track slabs. Operationally, workers can simply follow the steps of feeding, starting the motor, and adding water. The process is clear and easy to master, reducing operational difficulty and labor intensity. At the same time, the standardized process and stable operation of the device reduce the risk of safety accidents and ensure the personal safety of workers.
[0012] 2. Compared with traditional devices, this utility model, through its ingenious design in the concrete collection stage, greatly improves operational convenience and ensures collection accuracy. Regarding operational convenience, previously, workers had to expend considerable effort manually moving the collection container to the discharge port. With this device, workers only need to rotate the rotating block on the back of the fixing rod; with the cooperation of the limiting plate and the fixing rod, the collection box can be easily moved to a suitable position below the discharge pipe. Furthermore, the universal wheels hinged to the bottom column of the collection box and the push rod installed on the front allow for flexible and precise position adjustment, simplifying the operation process, saving time and effort, and improving overall work efficiency. Regarding collection accuracy, the reasonable control of the collection box position ensures that concrete falls accurately into it, avoiding spillage and waste, and preventing splashing around the device, maintaining a clean working environment and facilitating subsequent concrete processing and utilization. This ensures the stability and quality of concrete supply during track slab production, laying the foundation for high-quality track slab production. Attached Figure Description
[0013] Figure 1 This is a three-dimensional view of the front of this utility model. Figure 2 This is a side perspective view of the present invention. Figure 3 This is a three-dimensional view of the rear appearance structure of the present utility model; Figure 4 This is a schematic diagram of the front cross-sectional structure of this utility model; Figure 5 This is a schematic diagram of the collection box structure of this utility model; Figure 6 This is a schematic diagram of the scraper structure of this utility model.
[0014] In the diagram: 1. Support platform; 2. Mixing tank; 3. Diverter box; 4. Feed pipe; 5. Water pipe; 6. First rotating shaft; 7. Second rotating shaft; 8. Motor; 9. Support base; 10. Support plate; 11. Reinforcing rib; 12. Connecting plate; 13. Fixed base; 14. Fixed block; 15. Working box; 16. Collection box; 17. Push rod; 18. Column; 19. Caster wheel; 20. Drive wheel; 21. Transmission belt; 22. Driven gear; 23. Limiting plate; 24. Rotating block; 25. Fixed rod; 26. Spiral blade; 27. Check valve; 28. Discharge pipe; 29. Mixing rod; 30. Connecting rod; 31. Scraper. Detailed Implementation
[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0016] like Figures 1 to 6 As shown, this utility model provides a concrete mixing device for making track slabs, including a support platform 1, a mixing tank 2 fixedly installed on the top of the support platform 1, a second rotating shaft 7 movably installed inside the mixing tank 2, a connecting rod 30 movably installed on the outer surface of the second rotating shaft 7, a scraper 31 fixedly installed at one end of the connecting rod 30, and the outer side of the scraper 31 is in contact with the inside of the mixing tank 2, and a mixing rod 29 fixedly installed on the outer surface of the second rotating shaft 7. A diversion box 3 is fixedly installed on the top of the mixing tank 2, and a feed pipe 4 is fixedly installed on the top of the diversion box 3. A driven gear 22 is fixedly installed at one end of the second rotating shaft 7. A first rotating shaft 6 is movably installed inside the diversion box 3. A drive wheel 20 is fixedly installed at one end of the first rotating shaft 6, and a drive belt 21 is connected to the drive wheel 20. A spiral blade 26 is fixedly installed on the outer surface of the first rotating shaft 6. A motor 8 is fixedly installed on the left side of the mixing tank 2, and the output end of the motor 8 is fixedly connected to the second rotating shaft 7. A water inlet pipe 5 is fixedly installed on the left side of the mixing tank 2.
[0017] When using the concrete mixing device for making track slabs, the workers first put the raw materials needed to make concrete into the distribution box 3 through the feed pipe 4. Then, they start the motor 8. The output end of the motor 8 drives the second rotating shaft 7 to rotate. Since a driven gear 22 is fixedly installed at one end of the second rotating shaft 7, and the driven gear 22 is connected to the drive wheel 20 at one end of the first rotating shaft 6 through the transmission belt 21, the rotation of the second rotating shaft 7 will drive the first rotating shaft 6 to rotate. The rotation of the first rotating shaft 6 causes the spiral blades 26 fixedly installed on its outer surface to rotate, which evenly transports the raw materials in the distribution box 3. The material is fed into the mixing tank 2. At the same time, the second rotating shaft 7 rotates, driving the mixing rod 29 fixedly installed on its outer surface to mix the raw materials in the mixing tank 2. The rotation of the second rotating shaft 7 also drives the connecting rod 30 movably installed on its outer surface to rotate. The scraper 31 fixedly installed at one end of the connecting rod 30 is attached to the inside of the mixing tank 2. During the rotation, the scraper 31 can scrape off the raw materials attached to the inner wall of the mixing tank 2 to prevent raw material residue. In addition, the water pipe 5 is connected to an external water source to inject an appropriate amount of water into the mixing tank 2 and mix it thoroughly with the raw materials. Finally, the mixing and production of the track slab concrete is completed.
[0018] When using the concrete mixing device for making track slabs, the raw materials required for making concrete are first put into the distribution box 3 through the feed pipe 4. Then, the motor 8 is started, and its output end drives the second rotating shaft 7 to rotate. Since one end of the second rotating shaft 7 is equipped with a driven gear 22, which is connected to the drive wheel 20 at one end of the first rotating shaft 6 through the transmission belt 21, the rotation of the second rotating shaft 7 will drive the first rotating shaft 6 to rotate. The spiral blades 26 on the first rotating shaft 6 will rotate accordingly, evenly conveying the raw materials in the distribution box 3 to the mixing tank 2. At the same time, the second rotating shaft 7 drives the mixing rod 29 to mix the raw materials in the mixing tank 2. Moreover, the rotation of the second rotating shaft 7 causes the movable connecting rod 30 to rotate. The scraper 31 at one end of the connecting rod 30 adheres to the inner wall of the mixing tank 2, which can scrape off the attached raw materials and avoid residue. In addition, the workers connect the water pipe 5 to an external water source and inject an appropriate amount of water into the mixing tank 2 to allow the water to mix thoroughly with the raw materials, finally completing the track slab mixing process. Compared to traditional equipment, this concrete mixing and manufacturing system for track slabs offers several advantages. Firstly, a motor drives a second rotating shaft, which in turn drives a first rotating shaft via a transmission belt. The spiral blades of the first rotating shaft quickly and evenly transport raw materials from the distribution box to the mixing tank, preventing accumulation and shortening feeding time. Secondly, the mixing rods of the second rotating shaft simultaneously mix the materials. This multi-component collaboration ensures rapid and thorough mixing, meeting the demands of large-scale production. Thirdly, in terms of mixing quality, the connecting rod drives a scraper that rotates against the tank wall as the second rotating shaft rotates, promptly removing adhering materials and ensuring uniform mixing. Furthermore, the system's design ensures thorough integration of water and raw materials, resulting in stable concrete quality that meets the stringent strength and durability requirements for track slabs. Fourthly, operation is simple: workers follow a clear and easy-to-understand sequence of feeding, starting the motor, and adding water, reducing operational difficulty and labor intensity. Finally, the standardized process and stable operation of the equipment minimize the risk of accidents and ensure worker safety.
[0019] Among them, a limiting plate 23 is fixedly installed at the bottom of the support platform 1, a fixing rod 25 is movably installed inside the limiting plate 23, a collection box 16 is hinged to the front of the fixing rod 25, columns 18 are fixedly installed around the bottom of the collection box 16, a one-way valve 27 is fixedly installed inside the mixing tank 2, casters 19 are hinged to the bottom of the columns 18, a push rod 17 is fixedly installed on the front of the collection box 16, a rotating block 24 is fixedly installed on the back of the fixing rod 25, and a discharge pipe 28 is fixedly installed at the bottom of the support platform 1.
[0020] When the workers operate the concrete mixing device for making track slabs, after the concrete in the mixing tank 2 is mixed, the concrete will flow out through the discharge pipe 28. At this time, because the bottom of the support platform 1 is fixedly installed with a limiting plate 23, and the limiting plate 23 is movably installed with a fixing rod 25, the rotating block 24 on the back of the fixing rod 25 is rotated, so that the fixing rod 25 rotates within the limiting plate 23, thereby driving the collection box 16, which is hinged on the front, to move to a suitable position below the discharge pipe 28. The bottom of the collection box 16 is fixedly installed with columns 18, and the bottom of the columns 18 is hinged with casters 19, which facilitates the flexible movement and adjustment of the collection box 16. The front of the collection box 16 is fixedly installed with a push rod 17. Finally, the push rod 17 is held to push the collection box 16, so that the concrete flowing out of the discharge pipe 28 falls accurately into the collection box 16, completing the concrete collection work.
[0021] Once the concrete in mixing tank 2 is fully mixed, it flows out from discharge pipe 28. At this point, the limiting plate 23 installed at the bottom of support platform 1 comes into play. Inside, a fixing rod 25 is movably mounted. The operator rotates the rotating block 24 on the back of the fixing rod 25, causing it to rotate within the limiting plate 23. This moves the collection box 16, hinged to the front, to a suitable position below discharge pipe 28. The collection box 16 has columns 18 around its bottom, with casters 19 hinged to the bottom of each column, allowing for flexible movement and adjustment. A push rod 17 is located on the front of the collection box 16. The operator holds the push rod 17 and pushes the collection box 16, ensuring the flowing concrete falls accurately into it, thus successfully completing the collection process. Compared to traditional devices, this device, through its ingenious design in the concrete collection stage, greatly improves operational convenience and ensures collection accuracy. Regarding operational convenience… Previously, workers had to expend a lot of effort manually carrying the collection container to the discharge port to collect concrete. In this device, workers only need to rotate the rotating block 24 on the back of the fixing rod 25. With the cooperation of the limiting plate 23 and the fixing rod 25, the collection box 16 can be easily moved to a suitable position below the discharge pipe 28. In addition, the universal wheels 19 hinged to the bottom column 18 of the collection box 16 and the push rod 17 installed on the front can flexibly and accurately adjust the position, simplifying the operation process, saving time and physical strength, improving the overall work efficiency, and ensuring the accuracy of collection. The reasonable control of the position of the collection box 16 allows the concrete to fall accurately into it, avoiding spillage and waste and splashing around the device, keeping the working environment clean, and facilitating the subsequent processing and utilization of concrete. This ensures the stability and quality of concrete supply in the production of track slabs and lays the foundation for high-quality production of track slabs.
[0022] Among them, a support plate 10 is fixedly installed at the bottom of the support platform 1, and a connecting plate 12 is fixedly installed between the two support plates 10.
[0023] Since a connecting plate 12 is fixedly installed between the two support plates 10, the cooperation between the support plates 10 and the connecting plate 12 facilitates the provision of stable support for the support platform 1, ensuring the stability of the support platform 1 during use.
[0024] A reinforcing rib 11 is fixedly installed at the angle between the connecting plate 12 and the support plate 10, and the reinforcing rib 11 is triangular in shape.
[0025] Because the reinforcing rib 11 is triangular in shape at the angle between the connecting plate 12 and the support plate 10, and triangles have stability characteristics, the stability of the support plate 10 and the connecting plate 12 is guaranteed during use.
[0026] Among them, a fixed seat 13 is fixedly installed on the front of the support platform 1, a fixed block 14 is movably installed inside the fixed seat 13, and a work box 15 is fixedly installed on the front of the fixed block 14.
[0027] By holding the work box 15, the fixing block 14 is slowly inserted into the fixed seat 13. The fixed seat 13 limits and fixes the fixing block 14. By adding the work box 15, it is convenient for the staff to take out and place maintenance tools inside the work box 15, and to make timely adjustments to the stirring device.
[0028] Among them, a support base 9 is fixedly installed on the left side of the mixing tank 2, and the interior of the support base 9 is in the form of a U-shaped groove.
[0029] Because the inside of the support base 9 is in the form of a U-shaped groove on the left side of the mixing tank 2, and the inside of the support base 9 is in contact with the outer surface of the motor 8, it is convenient to provide stable support for the motor 8 and ensure the stability of the motor 8 during use.
[0030] Among them, the connecting rod 30 and the scraper 31 are in pairs, with a total of three sets on the outer surface of the second rotating shaft 7.
[0031] Since the connecting rod 30 and the scraper 31 are in pairs, there are three sets on the outer surface of the second rotating shaft 7. Through the cooperation between the connecting rod 30 and the scraper 31, it is convenient to scrape the inside of the support platform 1 in a timely manner, ensuring that the inside of the support platform 1 is clean.
[0032] Working principle and usage process of this utility model: When using the concrete mixing device for making track slabs, the workers first put the raw materials needed to make concrete into the distribution box 3 through the feed pipe 4. Then, they start the motor 8. The output end of the motor 8 drives the second rotating shaft 7 to rotate. Since a driven gear 22 is fixedly installed at one end of the second rotating shaft 7, and the driven gear 22 is connected to the drive wheel 20 at one end of the first rotating shaft 6 through the transmission belt 21, the rotation of the second rotating shaft 7 will drive the first rotating shaft 6 to rotate. The rotation of the first rotating shaft 6 causes the spiral blades 26 fixedly installed on its outer surface to rotate, which evenly transports the raw materials in the distribution box 3. The material is fed into the mixing tank 2. At the same time, the second rotating shaft 7 rotates, driving the mixing rod 29 fixedly installed on its outer surface to mix the raw materials in the mixing tank 2. The rotation of the second rotating shaft 7 also drives the connecting rod 30 movably installed on its outer surface to rotate. The scraper 31 fixedly installed at one end of the connecting rod 30 is attached to the inside of the mixing tank 2. During the rotation, the scraper 31 can scrape off the raw materials attached to the inner wall of the mixing tank 2 to prevent raw material residue. In addition, the water pipe 5 is connected to an external water source to inject an appropriate amount of water into the mixing tank 2 and mix it thoroughly with the raw materials. Finally, the mixing and production of the track slab concrete is completed.
[0033] When the workers operate the concrete mixing device for making track slabs, after the concrete in the mixing tank 2 is mixed, the concrete will flow out through the discharge pipe 28. At this time, because the bottom of the support platform 1 is fixedly installed with a limiting plate 23, and the limiting plate 23 is movably installed with a fixing rod 25, the rotating block 24 on the back of the fixing rod 25 is rotated, so that the fixing rod 25 rotates within the limiting plate 23, thereby driving the collection box 16, which is hinged on the front, to move to a suitable position below the discharge pipe 28. The bottom of the collection box 16 is fixedly installed with columns 18, and the bottom of the columns 18 is hinged with casters 19, which facilitates the flexible movement and adjustment of the collection box 16. The front of the collection box 16 is fixedly installed with a push rod 17. Finally, the push rod 17 is held to push the collection box 16, so that the concrete flowing out of the discharge pipe 28 falls accurately into the collection box 16, completing the concrete collection work.
[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0035] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A concrete mixing device for manufacturing track slabs, comprising a support platform (1), characterized in that: A mixing tank (2) is fixedly installed on the top of the support platform (1). A second rotating shaft (7) is movably installed inside the mixing tank (2). A connecting rod (30) is movably installed on the outer surface of the second rotating shaft (7). A scraper (31) is fixedly installed at one end of the connecting rod (30), and the outer side of the scraper (31) is attached to the inside of the mixing tank (2). A stirring rod (29) is fixedly installed on the outer surface of the second rotating shaft (7). A diversion box (3) is fixedly installed on the top of the mixing tank (2), and a feed pipe (4) is fixedly installed on the top of the diversion box (3). A driven gear (22) is fixedly installed at one end of the second rotating shaft (7). A first rotating shaft (6) is movably installed inside the diversion box (3). A drive wheel (20) is fixedly installed at one end of the first rotating shaft (6), and a drive belt (21) is connected to the drive wheel (20) and the drive belt (21). A spiral blade (26) is fixedly installed on the outer surface of the first rotating shaft (6). A motor (8) is fixedly installed on the left side of the mixing tank (2), and the output end of the motor (8) is fixedly connected to the second rotating shaft (7). A water inlet pipe (5) is fixedly installed on the left side of the mixing tank (2).
2. The concrete mixing device for manufacturing track slabs according to claim 1, characterized in that: A limiting plate (23) is fixedly installed at the bottom of the support platform (1). A fixing rod (25) is movably installed inside the limiting plate (23). A collection box (16) is hinged to the front of the fixing rod (25). Columns (18) are fixedly installed around the bottom of the collection box (16). A one-way valve (27) is fixedly installed inside the mixing tank (2). A caster wheel (19) is hinged to the bottom of the column (18). A push rod (17) is fixedly installed on the front of the collection box (16). A rotating block (24) is fixedly installed on the back of the fixing rod (25). A discharge pipe (28) is fixedly installed at the bottom of the support platform (1).
3. The concrete mixing device for manufacturing track slabs according to claim 1, characterized in that: A support plate (10) is fixedly installed at the bottom of the support platform (1), and a connecting plate (12) is fixedly installed between the two support plates (10).
4. A concrete mixing device for manufacturing track slabs according to claim 3, characterized in that: A reinforcing rib (11) is fixedly installed at the angle between the connecting plate (12) and the support plate (10), and the reinforcing rib (11) is triangular in shape.
5. A concrete mixing device for manufacturing track slabs according to claim 1, characterized in that: A fixed seat (13) is fixedly installed on the front of the support platform (1), a fixed block (14) is movably installed inside the fixed seat (13), and a work box (15) is fixedly installed on the front of the fixed block (14).
6. A concrete mixing device for manufacturing track slabs according to claim 1, characterized in that: A support base (9) is fixedly installed on the left side of the mixing tank (2), and the interior of the support base (9) presents a U-shaped groove.
7. A concrete mixing device for manufacturing track slabs according to claim 1, characterized in that: The connecting rod (30) and scraper (31) are arranged in pairs, with a total of three groups on the outer surface of the second rotating shaft (7).