A hybrid power-assist system for lifting windows

Abstract

The present invention discloses a hybrid power-assisting system for lifting windows, including a window frame, a window sash, a driving mechanism, a gas spring power-assisting mechanism and a counterweight power-assisting mechanism. The window frame is provided with an openable window sash, and the window frames on both sides of the window sash are provided with driving mechanisms for driving the window sash to open and close. Two groups of gas spring power-assisting mechanisms are provided in the top of the window frame, and the two groups of gas spring power-assisting mechanisms face opposite directions and are diagonally distributed along the window sash and connected to the side walls of the window sash. Counterweight power-assisting mechanisms are also provided on the tops of both sides of the window frame, and the counterweight power-assisting mechanisms are connected to another diagonal of the window sash. The present invention can save space in the window frame and prevent the increase in the size of the window frame from affecting the appearance by adopting a counterweighting scheme combining a gas spring power-assisting mechanism and a counterweight power-assisting mechanism. At the same time, it can also reduce the counterweight of the gas spring, thereby reducing the counterweight error caused by the temperature difference, thereby ensuring that the counterweight ratio of the heavy window sash is within the normal load range of the driving motor, and ensuring the normal operation of the window sash.

Description

Technical Field

[0001] The invention relates to the field of lifting window power assistance, and in particular to a lifting window hybrid power assistance system. Background Art

[0002] Window sashes are the main channels for indoor ventilation and light transmission. For this reason, the existing window sashes are relatively large in size and correspondingly heavy in weight. However, the increase in the weight of the window sashes also brings some other problems, such as being too heavy to open and close, and being difficult to install and debug. In order to reduce the weight of the existing window sashes, most of them use counterweights to reduce the weight of the window sashes, that is, window sash assist, and the counterweight methods mainly include counterweights or gas spring counterweights. Since the counterweights will occupy the size of the window frame, the thickness of the window frame will increase, affecting the beauty of the window sash, so the existing window sash counterweights mostly use gas springs. However, the gas spring itself has the following problems: 1. However, the force of the gas spring is not equal when the length is the same when it is extended and retracted. The gas spring itself has unequal force. For example, the elastic force of the gas spring when it is compressed 5cm in the free state and the gas spring when it returns to the free state from the compressed state is 5cm different from the free state, that is, the use of the gas spring is not equal to the force of the movement direction and movement distance. Therefore, the use environment of existing gas springs is mainly a hanging window, that is, the top of the window is hinged to the window frame, and the lower part of the window sash is opened by pushing it outward. When the gas spring is applied to a hanging window, there is a hinge point between the window and the window frame. These two hinge points can be decomposed to make the force of the gas spring tend to be equal. However, the application of the gas spring to the lifting window will cause the weight ratio of the lifting window to be inconsistent; 2. There is still a deviation of 10-20% in the force of the gas spring, that is, the elastic force of a 100kg gas spring is distributed in the range of 80-120kg. , while the 300kg gas spring has a wider distribution range of elastic force, which results in a large load range for the motor when the large and heavy lifting windows use the gas spring to assist; 3. The gas spring has temperature drift, that is, the gas spring has different force values ​​for the same specifications under different ambient temperatures, which makes it inconvenient to control the weight of the counterweight; 4. The elastic force of the gas spring is unevenly distributed during linear motion, resulting in unstable force value, which is specifically manifested in that only a small force is needed to compress the gas spring in the early stage of compression, and a large force is needed to compress the gas spring in the later stage of compression. The above problems will seriously affect the counterweight of the gas spring for heavy lifting windows. Due to the structure of the heavy lifting window, the gas spring can only move linearly when using the gas spring, and will directly act on the motor, resulting in an increase in the range of the motor load, affecting the stability of the motor operation. Therefore, there is a need for a power assist system that can reduce the counterweight error and make the counterweight of the window sash more stable to ensure the stability of the window sash's own weight. Summary of the invention

[0003] The purpose of the present invention is to provide a hybrid power-assisting system for lifting windows, which adopts a solution of gas spring plus counterweight block to reduce the counterweight deviation of the window sash, on the one hand to avoid the increase of window frame thickness, and on the other hand to ensure the weight stability of the window sash and avoid overload of the motor that drives the window sash to open and close.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] A hybrid power-assisting system for lifting windows comprises a window frame, a window sash, a driving mechanism, a gas spring power-assisting mechanism and a counterweight power-assisting mechanism, wherein the window frame is provided with an openable window sash, and the window frames on both sides of the window sash are provided with a driving mechanism for driving the window sash to open and close, the driving mechanism comprising a screw rod, a nut seat, a synchronous wheel and a synchronous belt, the two screw rods are respectively mounted in the window frames on both sides of the window sash, each screw rod is threadedly connected with a liftable nut seat, the nut seat is fixedly connected to the window sash, and synchronous wheels of equal height are mounted on the upper parts of the two screw rods, a synchronous belt sleeved on two synchronous wheels is provided in the top of the window frame, and a driving motor for driving the synchronous belt to rotate is also provided in the window frame, two groups of gas spring power-assisting mechanisms are provided in the top of the window frame, the two groups of gas spring power-assisting mechanisms are in opposite directions, are distributed diagonally along the window sash and are connected to the side walls of the window sash, and counterweight power-assisting mechanisms are also provided on the tops of both sides of the window frame, and the counterweight power-assisting mechanisms are connected to the other diagonal of the window sash.

[0006] The gas spring assist mechanism includes a gas spring, a fixed seat, a limiting wheel and a steel wire. There are multiple gas springs, which are connected end to end and installed horizontally on the top of the window frame. One end of the multiple gas springs connected end to end is connected to the fixed seat near the side wall of the window frame, and the other end is connected to the limiting wheel. A supporting wheel is installed inside the end of the fixed seat away from the gas spring. One end of the steel wire is connected to the lower part of the fixed seat, and the other end of the steel wire is connected downward to the window sash after passing through the limiting wheel and the supporting wheel in turn.

[0007] The fixing seat is fixedly connected to the window frame.

[0008] The counterweight assist mechanism includes a support frame, a bottom plate, a top plate, a pull plate, a guide wheel assembly, a counterweight module, a load-bearing wheel and a steel cable. The support frame is provided with a plurality of accommodating cavities, in which the counterweight modules are placed. The bottom and top of the support frame are respectively provided with a bottom plate and a top plate that match their contours. A pull plate that vertically penetrates the top plate, the support frame and the bottom plate is provided above the top plate. The bottom of the pull plate is fixedly connected to the bottom plate, and a connecting hole connected to the steel cable is processed on the pull plate above the top plate. Guide wheel assemblies that contact the inner wall of the window frame are installed at the four corners of each side wall of the support frame. The load-bearing wheel is installed on the top of the support frame, one end of the steel cable is connected to the connecting hole on the pull plate, and the other end is connected to the window sash after passing around the load-bearing wheel.

[0009] The support frame is composed of multiple frames spliced ​​in sequence, and multiple C-shaped limit grooves and limit blocks that cooperate with each other are processed on the side walls of adjacent frames. The C-shaped limit grooves and limit blocks are installed alternately on the side walls between adjacent frames and correspond one to one. Guide wheel assemblies are installed on the frames located at the four corners of the support frame.

[0010] The counterweight module includes a counterweight block and a weight adjustment block. The counterweight block is a plurality of encapsulated lead blocks of fixed weight, and the weight adjustment block is an iron block, cast iron or / and stainless steel block.

[0011] The nut seats on the two screw rods are at the same height.

[0012] The hybrid power-assist system for lifting windows provided by the present invention has the following beneficial effects:

[0013] (1) By adopting a weight-balancing scheme combining a gas spring assist mechanism and a counterweight block assist mechanism, the space in the window frame can be saved and the size of the window frame can be prevented from increasing and affecting the appearance. At the same time, the weight of the gas spring can be reduced, thereby reducing the weight-balancing error caused by the temperature difference, thereby ensuring that the weight-balancing ratio of the heavy window sash is within the normal load range of the drive motor to reduce the load of the drive mechanism. The hybrid assist method can also reduce the weight-balancing deviation of the heavy window sash, reduce the load range of the motor, and ensure the normal operation of the window sash;

[0014] (2) By installing a horizontally arranged gas spring assist mechanism in the top window frame, the thickness of the side wall of the window frame can be reduced, making the window sash more beautiful, and at the same time, the gas spring assist mechanism can be easily installed and maintained;

[0015] (3) By using multiple gas springs to form a whole, the number of gas springs can be adjusted according to the length of the window sash to facilitate the adjustment of the weight balance;

[0016] (4) By setting a counterweight assist mechanism, the corresponding support frame can be selected according to the thickness of the profile of the window frame side wall to ensure that the thickness of the window frame will not increase due to the increase in the size of the counterweight module. At the same time, the excess weight of the counterweight assist mechanism can also be decomposed by the gas spring assist mechanism to ensure the counterweight efficiency;

[0017] (5) By providing a support frame composed of multiple frames, the frames can be spliced ​​according to the size of the window frame, eliminating the process of customizing the support frame and making the installation of the support frame more convenient;

[0018] (6) By setting the encapsulated lead block and the weight adjustment block, the weight of the counterweight block can be easily adjusted to improve the installation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A schematic diagram of the structure provided by an embodiment of the present invention.

[0021] Figure 2 A schematic diagram of the internal structure provided by an embodiment of the present invention.

[0022] Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0023] Figure 4 A positional relationship diagram of the driving mechanism, gas spring assist mechanism and counterweight assist mechanism provided in an embodiment of the present invention.

[0024] Figure 5 A schematic diagram of the structure of a driving mechanism provided in an embodiment of the present invention.

[0025] Figure 6 A schematic structural diagram of a gas spring assist mechanism provided in an embodiment of the present invention.

[0026] Figure 7 A schematic diagram of the internal structure of a fixing base provided in an embodiment of the present invention.

[0027] Figure 8 A schematic structural diagram of a counterweight assist mechanism provided in an embodiment of the present invention.

[0028] Fig. 9 A schematic diagram of the internal structure of a support frame provided in an embodiment of the present invention.

[0029] Figure numerals: 1. window frame; 2. window sash; 3. driving mechanism; 31. screw rod; 32. nut seat; 33. synchronous wheel; 34. synchronous belt; 4. gas spring assist mechanism; 41. gas spring; 42. fixing seat; 43. limiting wheel; 44. steel wire; 45. supporting wheel; 5. counterweight block assist mechanism; 51. supporting frame; 511. frame body; 512. C-shaped limiting groove; 513. limiting block; 52. bottom plate; 53. top plate; 54. pull plate; 55. guide wheel assembly; 56. counterweight module; 57. load-bearing wheel; 58. steel cable. DETAILED DESCRIPTION

[0030] Example

[0031] like Figures 1 to 9As shown, the hybrid power-assisting system for lifting windows provided in this embodiment includes a window frame 1, a window sash 2, a driving mechanism 3, a gas spring power-assisting mechanism 4 and a counterweight power-assisting mechanism 5. The window frame 1 is provided with an openable window sash 2, and the window frames 1 on both sides of the window sash 2 are provided with driving mechanisms 3 for driving the window sash 2 to open and close. The driving mechanism 3 includes a screw rod 31, a nut seat 32, a synchronous wheel 33 and a synchronous belt 34. There are two screw rods 31, and the two screw rods 31 are respectively vertically and rotatably installed in the window frames 1 on both sides of the window sash 2. A nut seat 32 that can be raised and lowered is threadedly connected to each screw rod 31. The nut seat 32 is fixedly connected to the window sash 2, the nut seats 32 on the two screw rods 31 are at the same height, and the upper parts of the two screw rods 31 are equipped with synchronous wheels 33 at the same height. A synchronous belt 34 is provided on the top of the window frame 1 and is mounted on the two synchronous wheels 33. A driving motor for driving the synchronous belt 34 to rotate is also provided in the window frame 1. When the driving motor rotates, it drives the synchronous belt 34 to rotate, and the synchronous belt 34 drives the two screw rods 31 to rotate in the same direction, so that the nut seat 32 on the screw rod 31 is raised and lowered, thereby driving the window sash 2 to rise and fall to realize the opening and closing of the window sash 2. Two sets of gas spring assist mechanisms are provided on the top of the window frame 1. 4, the two groups of gas spring booster mechanisms 4 are in opposite directions and are diagonally distributed along the window sash 2 and connected to the side wall of the window sash 2. The gas spring booster mechanism 4 includes a gas spring 41, a fixing seat 42, a limiting wheel 43 and a steel wire 44. There are multiple gas springs 41, and the multiple gas springs 41 are horizontally installed on the top of the window frame 1 after being connected end to end. The use of multiple gas springs 41 can be adjusted according to the width of the window sash 2, eliminating the cost of customizing the gas springs 41. At the same time, the use of multiple gas springs 41 can be matched according to the actual weight of the window sash 2. For example, the counterweight required for the gas spring 41 is 20kg. When the weight is 60kg, three gas springs 41 can be directly selected to complete the selection of counterweights, which increases the convenience of installation. Multiple gas springs 41 connected end to end are connected to a fixed seat 42 at one end close to the side wall of the window frame 1, and are connected to a limiting wheel 43 at the other end. The fixed seat 42 is fixedly connected to the window frame 1, and the connection methods include screws, bolts, rivets, etc. A supporting wheel 45 is installed inside the end of the fixed seat 42 away from the gas spring 41, one end of the steel wire 44 is connected to the lower part of the fixed seat 42, and the other end of the steel wire 44 is connected to the window sash 2 downward after bypassing the limiting wheel 43 and the supporting wheel 45 in turn.The top of both sides of the window frame 1 is also provided with a counterweight block assist mechanism 5, which is connected to the other diagonal of the window sash 2. The counterweight block assist mechanism 5 includes a support frame 51, a bottom plate 52, a top plate 53, a pull plate 54, a guide wheel assembly 55, a counterweight module 56, a load-bearing wheel 57 and a steel cable 58. The support frame 51 is provided with a plurality of accommodating cavities, in which the counterweight modules 56 are placed. The bottom and top of the support frame 51 are respectively provided with a bottom plate 52 and a top plate 53 adapted to their contours, and a vertically penetrating top plate 53, top plate 53 is provided above the top plate 53. The pull plate 54 of the support frame 51 and the bottom plate 52, the bottom of the pull plate 54 is fixedly connected to the bottom plate 52, and a connecting hole connected to the steel cable 58 is processed on the pull plate 54 above the top plate 53. The four corners of each side wall of the support frame 51 are equipped with guide wheel assemblies 55 in contact with the inner wall of the window frame 1, and the load-bearing wheel 57 is installed on the top of the support frame 51. One end of the steel cable 58 is connected to the connecting hole on the pull plate 54, and the other end is connected to the window sash 2 after passing the load-bearing wheel 57. The steel cable 58 is the same as the steel wire 44, and is only named differently to distinguish the usage positions.

[0032] like Fig. 9 As shown, the support frame 51 is composed of a plurality of frame bodies 511 spliced ​​in sequence to adapt to window frames 1 of different sizes. A plurality of C-shaped limit grooves 512 and limit blocks 513 that cooperate with each other are processed on the side walls of adjacent frame bodies 511. The C-shaped limit grooves 512 and limit blocks 513 are respectively installed on the side walls between adjacent frame bodies 511 in an alternating manner and correspond one to one. Guide wheel assemblies 55 are installed on the frame bodies located at the four corners of the support frame 51. The guide wheel assemblies 55 can increase the smoothness of the movement of the counterweight block assist mechanism 5 in the window frame 1, ensure the counterweight efficiency, and effectively avoid the situation where the counterweight is affected by friction.

[0033] like Fig. 9As shown, the counterweight module 56 includes a counterweight block and a weight adjustment block. The counterweight block is a plurality of packaged lead blocks of fixed weight. Due to the high density of the lead block, under the counterweight blocks of the same weight, the lead block has the advantages of low cost and small size, which can effectively save space and reduce the size of the window frame 1. The use of packaged lead blocks can effectively avoid lead pollution. Since the counterweight weights of the window sashes 2 are different, the counterweight weight needs to be adjusted, and the packaged lead blocks cannot be cut, otherwise lead pollution will occur. For this reason, a weight adjustment block that can be cut and will not cause pollution is required. The weight adjustment block is an iron block, cast iron or / and stainless steel block. The weight adjustment block is preferably a strip block of uniform specifications. In this way, when the weight needs to be adjusted, accurate counterweighting can be performed by cutting weight adjustment blocks of different lengths to improve the counterweight efficiency. The weight adjustment blocks of the above materials can be arbitrarily Cutting will not generate pollution, and the counterweight can be adjusted according to the weight parameters in the actual assembly process. For example, if the counterweight module 56 is required to counterweight the window sash 2 with a weight of 101.6kg, two 50kg packaged lead blocks and two 0.8kg weight adjustment blocks are selected. The 0.8kg weight adjustment block can be calculated by cutting a fixed length. For example, if the material of the weight adjustment block is known, the length to be cut can be calculated according to the width of the cross section, and the weight adjustment block of fixed weight can be conveniently cut. Moreover, the weight adjustment block can be cut to improve the stocking efficiency. The company only needs to prepare large-volume packaged lead blocks and weight adjustment blocks. When the weight of the packaged lead blocks needs to be increased, the counterweight stocking can be completed by cutting the weight adjustment blocks of fixed length. There is no need to prepare counterweight blocks of various specifications, which reduces the production cost of the company.

[0034] The method of using the present invention is:

[0035] When in use, weigh the window sash 2 first, and then select the gas spring assist mechanism 4 and the counterweight assist mechanism 5 of corresponding weight after weighing, so that the overall counterweight of the gas spring assist mechanism 4 and the counterweight assist mechanism 5 is equal to the weight of the window sash 2. For example, if the weight of the window sash 2 is 300kg, select two groups of 100kg counterweight assist mechanisms 5 and two groups of 50kg gas spring assist mechanisms 4. Alternatively, select two groups of 75kg counterweight assist mechanisms 5 and two groups of 75kg gas spring assist mechanisms 4. It should be noted that in areas where the ambient temperature changes greatly, the weight proportion of the counterweight assist mechanism 5 is greater than the weight proportion of the gas spring assist mechanism 4, so as to reduce the environmental impact on the floating range of the gas spring 41 and control the counterweight weight of the assist system within the normal load range of the drive motor. Subsequently, the gas spring assist mechanism 4 and the counterweight assist mechanism 5 are assembled. When installing the gas spring assist mechanism 4, multiple gas springs 41 are connected end to end, and then the steel wire 44 is installed under the fixed seat 42. After the steel wire 44 is passed around the limiting wheel 43, the gas spring 41 is installed from the profile cavity of the window frame 1 into the window frame 1, and then the fixed seat 42 is fixed to the window frame 1. The steel wire 44 passes around the supporting wheel 45 on the fixed seat 42 and is downwardly connected to the window frame 1; when installing the counterweight assist mechanism 5, the counterweight module 56 is placed in the accommodating cavity in the support frame 51, and then the bottom plate 52, the top plate 53 and the pull plate 54 are fixed on the support frame 51, the support frame 51 is assembled into a whole, and the guide wheel assembly 55 is installed at the four corners of each side wall of the support frame 51, and then the steel cable 58 is connected to the connecting hole at the top of the pull plate 54, and then the steel cable 58 passes around the load-bearing wheel 57 installed on the top of the window frame 1 and is connected to the window sash 2. Two groups of gas spring assist mechanisms 4 and two groups of counterweight assist mechanisms 5 are installed diagonally at both ends of the window sash 2, which can ensure the stability of the window sash 2 and the stability of the operation of the window sash 2.

[0036] The mixed use of the gas spring booster mechanism 4 and the counterweight block booster mechanism 5 can avoid the temperature drift phenomenon caused by only using the gas spring 41 counterweight, and the situation that the thickness of the window frame 1 increases and affects the beauty of the window due to the counterweight block counterweight, which has the advantages of easy installation and debugging. At the same time, it can also prevent the problem of large fluctuation range of the counterweight weight, reduce the load of the drive motor, improve the stability of the window sash 2, and make the heavy window sash 2 suitable for use in an environment with a large temperature difference. In an environment with a large temperature difference, most of the counterweight force can be adjusted by the counterweight block booster mechanism 5. The counterweight block has a stable weight and does not change with environmental changes. Part of the counterweight force that needs to be adjusted is realized by the gas spring booster mechanism 4, which will not increase the thickness of the window frame and can also ensure that the counterweight force is within a small fluctuation range; in an environment with a small temperature difference, the counterweight force can be evenly distributed to the gas spring booster mechanism 4 and the counterweight block booster mechanism 5, which can ensure the beauty of the window and the stability of the counterweight of the window sash 2. The force value of the gas spring will not fluctuate too much, which ensures that the load range of the drive motor is small, making its operation more stable.

[0037] The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention shall be included in the protection scope of the present invention. It should be noted that the structures or components illustrated in the drawings are not necessarily drawn to scale, and the present invention omits the description of known components and processing technologies and processes to avoid unnecessary limitation of the present invention.

Claims

1. A hybrid power-assist system for lifting windows, characterized in that: It includes a window frame, a window sash, a driving mechanism, a gas spring assist mechanism and a counterweight assist mechanism. The window frame is provided with an openable window sash. The window frames on both sides of the window sash are provided with driving mechanisms for driving the window sash to open and close. The driving mechanism includes a screw rod, a nut seat, a synchronous wheel and a synchronous belt. There are two screw rods, which are respectively installed in the window frames on both sides of the window sash. Each screw rod is threadedly connected with a nut seat that can be raised and lowered. The nut seat is fixedly connected to the window sash. Synchronous wheels of equal height are installed on the upper parts of the two screw rods. A synchronous belt mounted on two synchronous wheels is provided in the top of the window frame. A driving motor for driving the synchronous belt to rotate is also provided in the window frame. Two groups of gas spring assist mechanisms are provided in the top of the window frame. Two groups of gas springs The power-assisting mechanisms are oriented in opposite directions and are distributed diagonally along the window sash and connected to the side walls of the window sash. A counterweight power-assisting mechanism is also provided on the top of both sides of the window frame, and the counterweight power-assisting mechanism is connected to the other diagonal of the window sash; the gas spring power-assisting mechanism comprises a gas spring, a fixed seat, a limiting wheel and a steel wire. There are multiple gas springs, which are horizontally installed on the top of the window frame after being connected end to end. One end of the multiple gas springs connected end to end is connected to a fixed seat close to the side wall of the window frame, and the other end is connected to a limiting wheel. A supporting wheel is installed inside the end of the fixed seat away from the gas spring, one end of the steel wire is connected to the lower part of the fixed seat, and the other end of the steel wire is connected downward to the window sash after bypassing the limiting wheel and the support wheel in turn; the nut seats on the two screw rods are at the same height.

2. The lift window hybrid power assist system according to claim 1, characterized in that: The fixing seat is fixedly connected to the window frame.

3. The lift window hybrid power assist system according to claim 1, characterized in that: The counterweight assist mechanism includes a support frame, a bottom plate, a top plate, a pull plate, a guide wheel assembly, a counterweight module, a load-bearing wheel and a steel cable. The support frame is provided with a plurality of accommodating cavities, in which the counterweight modules are placed. The bottom and top of the support frame are respectively provided with a bottom plate and a top plate that match their contours. A pull plate that vertically penetrates the top plate, the support frame and the bottom plate is provided above the top plate. The bottom of the pull plate is fixedly connected to the bottom plate, and a connecting hole connected to the steel cable is processed on the pull plate above the top plate. Guide wheel assemblies that contact the inner wall of the window frame are installed at the four corners of each side wall of the support frame. The load-bearing wheel is installed on the top of the support frame, one end of the steel cable is connected to the connecting hole on the pull plate, and the other end is connected to the window sash after passing around the load-bearing wheel.

4. The lift window hybrid power assist system according to claim 3, characterized in that: The support frame is composed of multiple frames spliced ​​in sequence, and multiple C-shaped limit grooves and limit blocks that cooperate with each other are processed on the side walls of adjacent frames. The C-shaped limit grooves and limit blocks are installed alternately on the side walls between adjacent frames and correspond one to one. Guide wheel assemblies are installed on the frames located at the four corners of the support frame.

5. The lift window hybrid power assist system according to claim 3, characterized in that: The counterweight module includes a counterweight block and a weight adjustment block. The counterweight block is a plurality of encapsulated lead blocks of fixed weight, and the weight adjustment block is an iron block, cast iron or / and stainless steel block.

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