Stair mould

Abstract

This application relates to a staircase mold, belonging to the technical field of building construction. It includes a base, with a main staircase block slidably inserted into the upper side of the base. The main staircase block is inclined, and multiple secondary staircase blocks are slidably abutted against one side of the main staircase block. An upper baffle is fixedly connected to the upper surface of the base on the side of the main staircase block away from the secondary staircase blocks. One side of the upper baffle slidably abuts against the side wall of the adjacent main staircase block and is perpendicular to it. A lower baffle is fixedly connected to the base on the side of the secondary staircase block away from the main staircase block. The side of the lower baffle closest to the adjacent secondary staircase block is slidably connected to the secondary staircase block, and the lower baffle is perpendicular to the side wall of the adjacent secondary staircase block. Two opposing enclosure plates are provided on the upper sides of the main staircase block and the multiple secondary staircase blocks, and a fixing plate is provided between the ends of two main staircase blocks. A driving assembly for moving the main staircase block and the multiple secondary staircase blocks is connected to the main staircase block and the multiple secondary staircase blocks. This application has the effect of being able to manufacture staircases of different sizes.

Description

Technical Field

[0001] This application relates to the technical field of building construction, and in particular to a staircase mold. Background Technology

[0002] As people's demands for quality of life increase, more and more high-rise buildings are being built in cities. In order to meet the different needs of people living inside the buildings, and considering fire safety and other reasons, each building is equipped with staircases for people to go up and down.

[0003] Currently, most staircases use prefabricated components produced in factories. During actual construction, these components are transported to the construction site for assembly, which greatly shortens the construction time. Furthermore, because the prefabricated components are produced in the factory in advance, standardized control of the staircase quality can be achieved.

[0004] Because different buildings are used for different purposes, the number of people that need to be accommodated by the staircases also varies. However, most staircase molds currently used are standardized molds. This means that when the required staircase size needs to be adjusted, it is necessary to start from the mold and remake the staircase, which is quite troublesome. Summary of the Invention

[0005] In order to manufacture stairs of different sizes, this application provides a stair mold.

[0006] The staircase mold provided in this application adopts the following technical solution: A stair mold includes a base, a main stair block slidably inserted into the upper side of the base, the main stair block being inclined, and a plurality of secondary stair blocks slidably abutting one side of the main stair block, each secondary stair block being slidably inserted into the base. An upper baffle is fixedly connected to the upper surface of the base on the side of the main stair block away from the secondary stair blocks, one side of the upper baffle slidably abutting against the side wall of an adjacent main stair block, and the upper baffle is perpendicular to the adjacent main stair block. A lower baffle is fixedly connected to the base on the side of the secondary stair block away from the main stair block, the side of the lower baffle close to the adjacent secondary stair block being slidably connected to the secondary stair block, and the lower baffle is perpendicular to the side wall of the adjacent secondary stair block. Two surrounding plates are provided on the upper side of the main stair block and the plurality of secondary stair blocks, the two surrounding plates being arranged opposite each other, and a fixing plate is provided between the ends of the two main stair blocks. A driving component for moving the main stair block and the plurality of secondary stair blocks is connected to the main stair block and the plurality of secondary stair blocks.

[0007] By adopting the above technical solution, the positions of the main stair block and multiple secondary stair blocks are adjusted by setting a driving component. Then, a surrounding panel is set on the upper side of the upper baffle, the main stair block, multiple secondary stair blocks and the lower baffle. After that, concrete is poured into the inside of the surrounding panel. This allows stair molds of different sizes to be produced according to different needs, reducing the problem of product monotony caused by stair molds being able to produce only a single size mold.

[0008] Optionally, the drive assembly includes a lifting hydraulic cylinder, which is connected to the main stair block and is capable of moving the main stair block along its tilt direction.

[0009] By adopting the above technical solution, the lifting hydraulic cylinder can drive the main blocks of the staircase to move, thereby realizing the adjustment of the staircase size.

[0010] Optionally, a drive screw is threaded into the lower side of each of the stair sub-blocks along the inclined direction of the stair sub-block.

[0011] By adopting the above technical solution and setting multiple drive screws, multiple stair sub-blocks can be moved by rotating the multiple drive screws, thereby adjusting the position of the multiple stair sub-blocks and thus adjusting the size of the staircase cast by the mold.

[0012] Optionally, a lifting rack is fixedly connected to the side of the main stair block near the secondary stair block. Each secondary stair block has a corresponding drive gear on its bottom side. Each drive gear is engaged with a driven intermediate wheel on the side near the lifting rack. Adjacent drive gears are connected by the driven intermediate wheel located in the middle. The driven intermediate wheel near the lifting rack is engaged with the lifting rack. Each drive gear is fixedly connected with a drive bevel gear. Each drive bevel gear is located on the lower side of the corresponding secondary stair block. Each drive bevel gear is engaged with a driven bevel gear. Each driven bevel gear is threaded onto the outside of the corresponding drive screw.

[0013] By adopting the above technical solution, during the process of the lifting hydraulic cylinder driving the main stair block to move, the main stair block drives the lifting rack to move. During the movement of the lifting rack, multiple drive gears and multiple driven intermediate gears rotate. During the rotation of each drive gear, the connected drive bevel gear rotates. Each drive bevel gear drives the connected driven bevel gear to rotate. Each driven bevel gear drives the connected drive screw to rotate. Thus, the drive screw can drive the secondary stair block to move, thereby reducing the trouble of needing to add a drive device to drive multiple drive screws to move.

[0014] Optionally, the lower sidewall of the enclosure is slidably connected to the adjacent main stair block, multiple secondary stair blocks, and the upper wall of the upper and lower baffles.

[0015] By adopting the above technical solution, and by setting up a sliding connection between the surrounding panel and the main and secondary stair blocks, the lateral length of the manufactured staircase can be adjusted.

[0016] Optionally, the upper side of the enclosure is provided with a leveling component capable of leveling the concrete inside the enclosure.

[0017] By adopting the above technical solution and setting up a leveling component, the space and cost required for setting up a robotic arm to level the concrete on the staircase mold are reduced.

[0018] Optionally, the leveling assembly includes a leveling rod, which is horizontally positioned and simultaneously slides against the side walls of both enclosures.

[0019] By adopting the above technical solution, the concrete inside the enclosure can be leveled by moving the leveling rod and keeping it in contact with the enclosure.

[0020] Optionally, each end of the leveling rod is connected to a connecting plate via a telescopic rod, the connecting plate being threaded through and connected to a leveling screw, and one end of the leveling screw being fixedly connected to a leveling motor.

[0021] By adopting the above technical solution, the scraping motor is started to drive the scraping screw to rotate. During the rotation of the scraping screw, the connecting plate and the scraping rod are moved, thereby reducing the trouble of manually moving the scraping rod.

[0022] Optionally, each of the telescopic rods includes a telescopic sleeve rod, one end of each telescopic sleeve rod is slidably connected to a telescopic connecting rod, and a spring is connected between each telescopic connecting rod and the inner wall of the telescopic sleeve rod.

[0023] By adopting the above technical solution, and by setting a telescopic rod to connect the leveling rod and the connecting plate, and by providing a spring inside the telescopic rod, the leveling rod can perform a leveling operation on the non-horizontal surface on the upper side of the enclosure plate under the tension of the spring during the movement of the leveling rod driven by the connecting plate.

[0024] Optionally, the bottom of the connecting plate is provided with a vibrating cam, which can abut against the side wall of the base during rotation. A vibrating gear is fixedly connected to the lower side of the vibrating cam. The vibrating gear is rotatably connected to the connecting plate, and a vibrating rack is meshed on one side of the vibrating gear. The vibrating rack is fixedly connected to the base.

[0025] By adopting the above technical solution and setting a vibrating cam, the connecting plate drives the vibrating cam and the vibrating gear to rotate during the movement of the connecting plate. Since the vibrating gear meshes with the vibrating rack, the vibrating gear can drive the vibrating cam to rotate during the movement, so that the vibrating cam can knock and vibrate the side wall of the base, thereby reducing the trouble of adding a vibrating device to vibrate the concrete on the upper side of the base.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By setting up a driving component to move the main stair block and multiple secondary stair blocks, and by setting up an upper baffle, lower baffle, surrounding plate and fixing plate to block the upper side of the main stair block and multiple secondary stair blocks, the mold can realize the production of staircases of different sizes; 2. By setting up a leveling component, the concrete inside the enclosure can be leveled, which facilitates the construction process of the stairs. 3. By setting a vibrating cam, the concrete inside the enclosure can be vibrated, thereby reducing the phenomenon that air bubbles in the concrete affect the quality of the finished staircase. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0028] Figure 2 This is a cross-sectional view of the overall structure of an embodiment of this application.

[0029] Figure 3 This is a cross-sectional view showing the connection relationship between the leveling component and the vibrating cam in an embodiment of this application.

[0030] Explanation of reference numerals in the attached drawings: 1. Base; 11. Upper baffle; 12. Upper support plate; 13. Lower baffle; 14. Lower support plate; 2. Main stair block; 21. Support block; 3. Sub-stair block; 4. Enclosure; 41. Fixing plate; 5. Drive assembly; 51. Lifting hydraulic cylinder; 52. Lifting rack; 53. Drive gear; 54. Driven intermediate wheel; 55. Drive shaft; 56. Drive bevel gear; 57. Driven bevel gear; 58. Drive screw; 6. Leveling assembly; 61. Leveling rod; 62. Telescopic rod; 621. Telescopic sleeve rod; 622. Telescopic connecting rod; 63. Spring; 64. Connecting plate; 65. Leveling screw; 66. Leveling motor; 67. Limiting rod; 7. Vibrating cam; 71. Vibrating gear; 72. Vibrating rack. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1 -Appendix Figure 3 This application will be described in further detail.

[0032] This application discloses a staircase mold, referring to... Figure 1 The system includes a base 1, with a downward-facing groove on the upper surface of the base 1. A main stair block 2 is attached to the side wall of the base 1. The main stair block 2 is inclined from top to bottom and is rectangular in shape. Multiple secondary stair blocks 3 are attached to the side wall of the base 1 on one side of the main stair block 2. The number of secondary stair blocks 3 can be adjusted according to the number of steps in the staircase.

[0033] The side walls of every two adjacent stair sub-blocks 3 slide against each other, and the stair sub-block 3 closest to the stair main block 2 slides against the side wall of the adjacent stair main block 2. Multiple stair sub-blocks 3 are parallel to the upper side wall of the stair main block 2.

[0034] The main stair block 2 is slidably abutted against the side of the stair sub-block 3 by an upper baffle 11, which is perpendicular to the side wall of the main stair block. The lower side wall of the upper baffle 11 is fixedly connected to two opposing upper support plates 12, and the lower side of each upper support plate 12 is fixedly connected to the side wall of the adjacent base 1.

[0035] A lower baffle 13 is slidably abutted against the side wall of the stair sub-block 3, which is away from the main stair block 2. The lower baffle 13 is perpendicular to the side wall of the adjacent stair sub-block 3. Two opposing lower support plates 14 are provided on the lower side of the stair sub-block 3. The lower side wall of each lower support plate 14 is fixedly connected to the side wall of the adjacent base 1.

[0036] The upper sides of the main stair block 2, multiple secondary stair blocks 3, upper baffle 11, and lower baffle 13 are provided with two opposing surrounding plates 4. Multiple grooves are formed on the lower side of the surrounding plates 4, allowing the lower sidewalls of the surrounding plates 4 to simultaneously abut against the upper sidewalls of the upper baffle 11, main stair block 2, secondary stair blocks 3, and lower baffle 13. The surrounding plates 4 are vertically positioned and slide horizontally connected to the upper sidewalls of the abutting upper baffle 11, main stair block 2, secondary stair blocks 3, and lower baffle 13. The upper sidewalls of the two surrounding plates 4 are at the same height at corresponding positions. A fixing plate 41 is provided between each adjacent end of the two surrounding plates 4. The fixing plate 41 is perpendicular to the surrounding plate 4, and each sidewall of the baffle near the surrounding plate 4 is slidably connected to the sidewall of the adjacent end of the surrounding plate 4.

[0037] The base 1 is connected to a drive component 5, which is used to drive the main stair block 2 and the multiple connected stair sub-blocks 3 to move. The movement direction of the main stair block 2 and the multiple stair sub-blocks 3 is the same as their own tilt direction.

[0038] First, based on the required stair tread height, activate drive component 5. Drive component 5 moves the main stair block 2 and multiple secondary stair blocks 3 to adjust the stair tread height formed by the stair mold. Then, place two side panels 4 on the upper baffle 11, the main stair block 2, the multiple secondary stair blocks 3, and the lower baffle 13. Then, pour concrete between the two side panels 4 and the two fixed plates 41. After the concrete dries, the staircase will be formed.

[0039] The drive component 5 drives the main stair block 2 and multiple secondary stair blocks 3 to move, and makes the movement speed of the main stair block 2 and multiple secondary stair blocks 3 different. This results in differences in the side wall movement distance between adjacent main stair blocks 2 and secondary stair blocks 3, as well as between two adjacent secondary stair blocks 3, after the movement. This allows the step height of the later cast staircase to be adjusted.

[0040] Reference Figure 1 and Figure 2 Support blocks 21 are fixedly connected to the two opposite side walls of the main stair block 2, and the support blocks 21 are located on the two side walls of the main stair block 2 that are not connected to the secondary stair block 3 and the upper baffle 11.

[0041] The drive assembly 5 includes a lifting hydraulic cylinder 51 fixedly connected to the lower side of each support block 21. The tilting direction of each lifting hydraulic cylinder 51 is the same as the tilting direction of the connected stair main block 2. The piston rod end of the lifting hydraulic cylinder 51 is fixedly connected to the lower surface of the support block 21, and the cylinder body of the lifting hydraulic cylinder 51 is fixedly connected to the side wall of the adjacent base 1.

[0042] The main stair block 2 is connected to a support block 21, and a lifting rack 52 is fixedly connected to one side of the main stair block 3 to which it is connected. The length direction of the lifting rack 52 is the same as the inclination direction of the main stair block 2 to which it is connected. Each lower side of each stair block 3 is provided with a corresponding drive gear 53, and each drive gear 53 is located in the same vertical plane as the lifting rack 52. Each drive gear 53 has a driven intermediate wheel 54 meshing on the side of the drive rack near the drive gear. The driven intermediate wheel 54 located between two drive gears 53 meshes with the drive gears 53 on both sides at the same time, and the driven intermediate wheel 54 near the lifting rack 52 meshes with the lifting rack 52.

[0043] Each drive gear 53 is penetrated and fixedly connected to a horizontally arranged drive shaft 55. The end of each drive shaft 55 away from the drive gear 53 penetrates the side wall of the base 1 and is rotatably connected to the side wall of the base 1. The end of each drive shaft 55 inside the base 1 is located on the lower side of the corresponding stair sub-block 3. Each drive shaft 55 is fixedly connected to a drive bevel gear 56 at its end. Each drive bevel gear 56 is meshed with a driven bevel gear 57 on its lower side. Each driven bevel gear 57 is fixedly connected to a drive screw 58 in the middle. The length direction of each drive screw 58 is the same as the inclination direction of the corresponding stair sub-block 3. The upper end of each drive screw 58 is threaded into the interior of the corresponding stair sub-block 3, and the lower end of each drive screw 58 is rotatably connected to the bottom side wall of the adjacent base 1.

[0044] When it is necessary to adjust the step height of the staircase made by the mold, the two lifting hydraulic cylinders 51 are activated. The two lifting hydraulic cylinders 51 drive the main staircase block 2 to move along the inclined direction of the main staircase block 2. During the movement, the main staircase block 2 drives the lifting rack 52 to move. During the movement, the lifting rack 52 drives the meshing driven intermediate wheel 54 to rotate. During the rotation, the driven intermediate wheel 54 drives the multiple connected drive gears 53 and the driven intermediate wheel 54 to rotate.

[0045] During the rotation of each drive gear 53, the connected drive shaft 55 is driven to rotate. During the rotation of each drive shaft 55, the connected drive bevel gear 56 is driven to rotate. During the rotation of each drive bevel gear 56, the meshing driven bevel gear 57 is driven to rotate. During the rotation of each driven bevel gear 57, the connected drive screw 58 is driven to rotate. During the rotation of each drive screw 58, the connected stair sub-block 3 is moved, thereby realizing the movement of the stair main block 2 and multiple stair sub-blocks 3.

[0046] Reference Figure 2 and Figure 3 The upper side of the two enclosure panels 4 is also provided with a leveling component 6, which is used to level the concrete between the two enclosure panels 4.

[0047] By setting up the leveling component 6, the casting process of the stairs can be made more convenient.

[0048] The leveling assembly 6 includes leveling rods 61 located on the upper sides of the two side panels 4. The leveling rods 61 are horizontally positioned and simultaneously abut against the two side panels 4. Each end of the leveling rod 61 is rotatably connected to a vertically downward-positioned telescopic rod 62. Each telescopic rod 62 includes a telescopic sleeve rod 621 whose end is rotatably connected to the leveling rod 61. The lower end of each telescopic sleeve rod 621 is slidably inserted upwards with a telescopic connecting rod 622. One end of each telescopic connecting rod 622 located inside the telescopic sleeve rod 621 is fixedly connected to a spring 63. The spring 63 is a tension spring 63. The end of each spring 63 away from the connected telescopic connecting rod 622 is fixedly connected to the inner wall of the opposite telescopic sleeve rod 621.

[0049] The lower ends of the two telescopic connecting rods 622 are fixedly connected to the same connecting plate 64, which is horizontal and penetrates the bottom side wall of the base 1. One end of the connecting plate 64 located outside the base 1 is threaded through and connected to a leveling screw 65. A leveling motor 66 is provided at one end of the leveling screw 65. Both the leveling screw 65 and the leveling motor 66 are horizontally arranged, and one end of the leveling screw 65 is fixedly connected to the output shaft end of the leveling motor 66.

[0050] The end of the connecting plate 64 away from the scraping screw 65 is penetrated and slidably connected to the limiting rod 67. The limiting rod 67 is horizontally set and the end of the limiting rod 67 is fixedly connected to the side wall of the adjacent base 1.

[0051] When it is necessary to level the concrete inside the enclosure 4, the leveling motor 66 is started. The leveling motor 66 drives the leveling screw 65 to rotate. During the rotation, the leveling screw 65, in conjunction with the limiting rod 67, drives the connecting plate 64 to move. During the movement of the connecting plate 64, it drives the two connected telescopic rods 62 to move. During the movement of the two telescopic rods 62, it drives the leveling rod 61 to move along the length direction of the two enclosures 4, thereby realizing the leveling operation of the concrete inside the enclosure 4. Furthermore, since the telescopic rods 62 are equipped with springs 63, the leveling rod 61 can adapt to the different grooves set on the upper surface of the enclosure 4.

[0052] A vibrating cam 7 is provided on the upper side of the connecting plate 64 inside the base 1. The vibrating cam 7 can abut against the adjacent side wall of the base 1 during rotation. A vibrating gear 71 is fixedly connected to the lower side of the vibrating cam 7, and the lower side of the vibrating gear 71 is rotatably connected to the connecting plate 64. A vibrating rack 72 is meshed on one side of the vibrating gear 71. The vibrating rack 72 is arranged parallel to the scraping screw 65, and the vibrating rack 72 is fixedly connected to the adjacent side wall of the base 1.

[0053] During the movement of the connecting plate 64, the connecting plate 64 drives the vibrating gear 71 and the vibrating cam 7 to move. Due to the presence of the vibrating rack 72, the vibrating gear 71 can rotate by meshing with the rack during the movement, thereby enabling the vibrating gear 71 to drive the vibrating cam 7 to rotate while moving, so that the vibrating cam 7 can strike the side wall of the base 1, thereby realizing the vibration operation of the concrete inside the enclosure 4.

[0054] The implementation principle of a stair mold in this application embodiment is as follows: when it is necessary to cast a stair, the drive assembly 5 is activated to drive the main stair block 2 and multiple stair sub-blocks 3 to move and adjust the step height, and then the surrounding plate 4 and the baffle are set on the upper side of the main stair block 2 and multiple stair sub-blocks 3.

[0055] Then, concrete is poured into the interior of the enclosure 4. After the concrete pouring is completed, the leveling motor 66 is started to drive the leveling rod 61 to move and level the concrete inside the enclosure 4. At the same time, the connecting plate 64 drives the vibrating cam 7 to move and tap and vibrate the side wall of the base 1, so that the air bubbles inside the concrete diffuse to the outside of the concrete, thus realizing the construction process of the staircase.

[0056] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A staircase mold, characterized in that: The system includes a base (1), on which a main stair block (2) is slidably inserted. The main stair block (2) is inclined. Multiple secondary stair blocks (3) are slidably abutted against one side of the main stair block (2). Each secondary stair block (3) is slidably inserted into the base (1). An upper baffle (11) is fixedly connected to the upper surface of the base (1) on the side of the main stair block (2) away from the secondary stair blocks (3). One side of the upper baffle (11) slidably abuts against the side wall of the adjacent main stair block (2), and the upper baffle (11) is perpendicular to the adjacent main stair block (2). The secondary stair blocks (3) away from the main stair block (2) are far from the main stair block (2). A lower baffle (13) is fixedly connected to the base (1) on one side of the main block (2). The lower baffle (13) is slidably connected to the adjacent stair sub-block (3) on the side close to it. The lower baffle (13) is perpendicular to the side wall of the adjacent stair sub-block (3). Two surrounding plates (4) are provided on the upper side of the main stair block (2) and the multiple stair sub-blocks (3). The two surrounding plates (4) are arranged opposite to each other. A fixing plate (41) is provided between the ends of the two main stair blocks (2). A driving component (5) for moving the main stair block (2) and the multiple stair sub-blocks (3) is connected to the main stair block (2) and the multiple stair sub-blocks (3). The drive assembly (5) includes a lifting hydraulic cylinder (51), which is connected to the main stair block (2) and can drive the main stair block (2) to move along the tilt direction of the main stair block (2). Each of the stair sub-blocks (3) has a drive screw (58) threaded into its lower side along the inclined direction of the stair sub-block (3); A lifting rack (52) is fixedly connected to the side of the main stair block (2) near the secondary stair block (3). A drive gear (53) is provided on the bottom side of each secondary stair block (3). A driven intermediate wheel (54) is meshed on the side of each drive gear (53) near the lifting rack (52). Two adjacent drive gears (53) are connected by meshing through the driven intermediate wheel (54) located in the middle. The driven intermediate wheel (54) near the lifting rack (52) meshes with the lifting rack (52). A drive bevel gear (56) is fixedly connected to each drive gear (53). Each drive bevel gear (56) is located on the lower side of the corresponding secondary stair block (3). Each drive bevel gear (56) is meshed with a driven bevel gear (57). Each driven bevel gear (57) is fixedly sleeved to the outside of the corresponding drive screw (58).

2. A staircase mold according to claim 1, characterized in that: The lower sidewall of the enclosure (4) is slidably connected to the adjacent main stair block (2), multiple secondary stair blocks (3), and the upper walls of the upper baffle (11) and the lower baffle (13).

3. A staircase mold according to any one of claims 1-2, characterized in that: The upper side of the enclosure (4) is provided with a leveling component (6) capable of leveling the concrete inside the enclosure (4).

4. A staircase mold according to claim 3, characterized in that: The leveling assembly (6) includes a leveling rod (61), which is horizontally positioned and simultaneously slides against the upper sidewalls of the two enclosures (4).

5. A staircase mold according to claim 4, characterized in that: Each end of the leveling rod (61) is connected to a connecting plate (64) via a telescopic rod (62). The connecting plate (64) is threaded through and connected to a leveling screw (65). One end of the leveling screw (65) is fixedly connected to a leveling motor (66).

6. A staircase mold according to claim 5, characterized in that: Each of the telescopic rods (62) includes a telescopic sleeve rod (621), and a telescopic connecting rod (622) is slidably inserted into one end of each telescopic sleeve rod (621). A spring (63) is connected between each telescopic connecting rod (622) and the inner wall of the telescopic sleeve rod (621).

7. A staircase mold according to claim 6, characterized in that: The bottom of the connecting plate (64) is provided with a vibrating cam (7). The vibrating cam (7) can abut against the side wall of the base (1) during rotation. A vibrating gear (71) is fixedly connected to the lower side of the vibrating cam (7). The vibrating gear (71) is rotatably connected to the connecting plate (64), and a vibrating rack (72) meshes with one side of the vibrating gear (71). The vibrating rack (72) is fixedly connected to the base (1).

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