Variable stiffness type lightweight emergency descent control device based on fiber reinforced composite material

Abstract

The variable stiffness type lightweight emergency descent control device based on the fiber reinforced composite material comprises a box body, a rotating shaft, a descent control mechanism, a rope and a damping assembly, one end of the rope is used for being connected with a load, and the rope drives the rotating shaft to rotate through the descent control mechanism and then drives the damping assembly to rotate; the slow descending mechanism comprises a sun gear, an inner gear and a planetary gear; the inner gear is driven by a rope, the planetary gear is meshed with the inner gear, and the sun gear is meshed with the planetary gear; the damping assembly comprises at least one rotating vane and a brush type damping block, the rotating vane rotates along with the rotating shaft to generate centrifugal force, and the brush type damping block is arranged on a rotating path of the rotating vane; the brush type damping blocks have rigidity gradients with the rigidity gradually increased from inside to outside in the radial direction. According to the emergency descent control device, through the cooperation mechanism of planetary gear efficient centrifugal driving and brush type variable stiffness damping block graded buffering, precise adaptation of the descent speed and the speed reduction effect is achieved, and the emergency descent control device becomes the core breakthrough direction in the technical field of current descent control devices.

Description

Technical Field

[0001] This invention belongs to the technical field of high-altitude escape equipment, specifically a variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials. Background Technology

[0002] In the field of high-altitude emergency rescue, the performance of the descent device directly determines the escape success rate. Current mainstream products, limited by material selection and structural design, suffer from three major pain points that severely restrict emergency rescue effectiveness and urgently need to be addressed: (1) Material limitations lead to large product weight: The core components of existing descent devices are mostly made of metal materials such as steel and aluminum alloy. Although they can meet the basic load-bearing requirements, they have high density (steel density 7.85g / cm³, aluminum alloy 2.7g / cm³), and the weight of the whole machine is generally 8-15kg. When firefighters carry equipment to climb high-rise buildings, the extra weight will increase physical exertion and delay the rescue progress; in home emergency scenarios, the elderly, children and other groups have difficulty operating independently and miss the best escape opportunity.

[0003] (2) Damping friction heat generation: The mainstream centrifugal descent devices on the market rely on the hard contact between the centrifugal block and the metal friction ring to generate damping. When the load increases from 30kg (child) to 100kg (adult), the centrifugal force changes by 200%-300%. However, the damping force adjustment only depends on the change of the contact area of ​​the friction pair, which cannot achieve precise matching. The descent speed fluctuation range often exceeds ±0.6m / s, far exceeding the safety threshold (±0.2m / s). Moreover, the instantaneous temperature during the friction process can reach more than 200℃, and the wear rate of the metal friction pair is accelerated. The friction components need to be replaced after 500 uses. Although non-Newtonian fluid descent devices do not have friction wear problems, when used alone, the fluid viscosity response lag time reaches 0.3-0.5s. In the case of sudden acceleration, "brief loss of resistance" is likely to occur. In the escape from a high-rise building above 10 stories, it may cause the person to fall a distance of more than 1.5m, which poses a safety hazard.

[0004] (3) The contradiction between lightweight and strength is difficult to balance: In order to solve the weight problem, some manufacturers have tried to use thin-walled metal structures (the wall thickness is reduced to 1.5-2mm), but the strength is reduced by 30%-40%, and the box is prone to deformation when subjected to a 150kg ultimate load; a few products use ordinary engineering plastics (such as ABS, PP), which reduce the weight by 40%, but have poor high temperature resistance (heat distortion temperature <100℃), are prone to softening and collapse in fire scenarios, and have insufficient impact resistance. They may be damaged if the drop height exceeds 1m, and cannot meet the stringent requirements of emergency scenarios. Summary of the Invention

[0005] The technical problem to be solved by this invention is as follows: In view of the technical problems existing in the prior art, this invention provides a variable stiffness lightweight emergency descent device based on fiber reinforced composite materials. Through the synergistic mechanism of "high-efficiency centrifugal drive of planetary gears and graded buffering of brush-type variable stiffness damping blocks", it overcomes the defects of traditional descent devices such as no gradient, easy wear, temperature sensitivity and heavy weight, and achieves precise matching of descent speed and deceleration effect, which has become the core breakthrough direction in the current field of descent device technology.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials includes a housing, a rotating shaft, a descent mechanism, a rope, and a damping assembly. One end of the rope is used to connect to a load. The rotating shaft passes through the center of the housing, the descent mechanism, and the damping assembly. The rope drives the rotating shaft to rotate via the descent mechanism, which in turn drives the damping assembly to rotate. The descent mechanism includes a sun gear, an internal gear, and at least one planetary gear. The internal gear is driven by the rope, and the internal gear of the planetary gear meshes with the sun gear. The damping assembly includes at least one blade and a brush-type damping block. The blade generates centrifugal force as it rotates with the rotating shaft. The brush-type damping block is disposed on the rotation path of the blade. The brush-type damping block has a stiffness gradient that increases radially from the inside to the outside.

[0007] Preferably, in the above technical solution, the emergency descent device further includes a take-up shaft, which is rotatably mounted on a rotating shaft via a bearing. The rope is wound around the take-up shaft, with one end of the rope fixed to the take-up shaft and the other end used to connect to a load.

[0008] Preferably, in the above technical solution, the slow-descent mechanism includes an internal gear, a planetary carrier, planetary gears, and a sun gear. The planetary carrier and the internal gear are mounted on the rotating shaft, and bearings are respectively provided between the planetary carrier and the internal gear and the rotating shaft. The internal gear is connected to the take-up shaft, and the sun gear is fixedly mounted on the rotating shaft.

[0009] Preferably, in the above technical solution, the planetary carrier is fixed on the rotating shaft, and the planetary carrier is provided with 3 supports, which are used to install 3 planetary gears respectively, and the included angle between adjacent supports is 60°.

[0010] Preferably, in the above technical solution, the damping component is installed inside the housing. The damping component includes a brush-type damping block, a rotating blade, and a rotating cylinder. The rotating cylinder is fixedly installed on the rotating shaft. The rotating cylinder is provided with multiple slots, each slot is arranged radially along the rotating cylinder, and the multiple slots are evenly distributed circumferentially along the rotating cylinder.

[0011] Preferably, in the above technical solution, the inner wall of the box is provided with multiple mounting grooves along the circumference, and multiple brush-type damping blocks are provided. The brush-type damping blocks are installed on the inner wall of the box by wedge-shaped buckles.

[0012] Preferably, in the above technical solution, the stiffness of the brush-type damping block increases radially and is divided into an inner layer, a middle layer and an outer layer, with corresponding stiffnesses of 50-80 N / mm, 120-150 N / mm and 200-250 N / mm, respectively.

[0013] Preferably, in the above technical solution, the emergency descent device further includes a dynamic matching design for the damping force and the load: (1) Establish a damping force demand calculation model Minimum damping force required for load range of 30kg-150kg. The formula is: in, This refers to the load weight; The maximum descent speed for safety; The stroke in which the damping force acts; μ The coefficient of friction between the rope and the take-up spool; It is the acceleration due to gravity; (2) Stiffness gradient optimization of brush-type damping blocks The brush-type damping block adopts a three-stage thickness gradient design: the inner layer is 8-10mm thick, the middle layer is 12-15mm thick, and the outer layer is 18-22mm thick, with corresponding stiffnesses of 50-80N / mm, 120-150N / mm, and 200-250N / mm, respectively.

[0014] Preferably, in the above technical solution, the emergency descent device further includes the design of the number of teeth and diameter of the planetary gears: (1) Derivation of gear module: Gear module The calculation formula is: in, The torque transmitted by the internal gear is derived from the load. For load factor; This is the tooth width coefficient; This refers to the number of teeth on the internal gear. The allowable bending stress for gear material; (2) The planetary gears are evenly distributed, and the transmission ratio is... The design is 5-8, which satisfies: in, The number of teeth on the sun gear. This refers to the number of teeth on the internal gear. (3) Gear pitch circle diameter: , d The pitch circle diameter of the gear; The gear module; This represents the number of teeth on the gear.

[0015] The present invention provides a variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials, which has the following advantages compared with the prior art: (1) The variable stiffness lightweight emergency descent device based on fiber reinforced composite material of the present invention overcomes the defects of existing descent devices such as no gradient deceleration, severe metal wear, strong temperature sensitivity, large weight, inconvenient operation, as well as the defects of other descent devices such as lag in variable damping adjustment and poor material adaptability. It provides an adaptive descent device based on planetary gears and variable stiffness damping blocks. The planetary gear structure efficiently amplifies the centrifugal force, and the trapezoidal cross section variable stiffness rubber damping block realizes gradient deceleration. Through the selection of special materials such as polytetrafluoroethylene blades, aramid fiber ropes, ultra-high molecular weight polyethylene gears and carbon fiber composites, the device achieves a comprehensive improvement in lightweight, weather resistance, durability and ease of operation, ensuring safe and stable descent under different working conditions.

[0016] (2) The variable stiffness lightweight emergency descent device based on fiber reinforced composite material of the present invention adopts a brush-type fiber density gradient design to achieve a continuous stiffness transition of the damping block from "soft" to "hard" (stiffness change rate ≤ 5N / mm), avoids sudden changes in damping force, and improves descent stability; and through the deceleration mechanism of the brush-type damping block, the problem of frictional heat generation of the friction descent device is avoided, which can achieve higher and more extreme high-rise rescue. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the emergency descent device of the present invention.

[0018] Figure 2 This is a schematic diagram of the damping component in this invention.

[0019] Figure 3 This is a schematic diagram of the connection structure of the brush-type damping block in this invention.

[0020] Figure 4 This is a schematic diagram of the rotating cylinder in this invention.

[0021] Figure 5 This is a schematic diagram of the structure of the box in this invention.

[0022] Figure 6 This is a schematic diagram of the brush-type damping block in this invention.

[0023] Explanation of the labels in the diagram: 1. Housing; 11. Mounting slot; 2. Take-up spool; 21. Rope; 3. Internal gear; 4. Planetary carrier; 41. Bracket; 5. Planetary gear; 6. Sun gear; 7. Rotating blade; 71. Rotating drum; 72. Slot; 73. Spring; 8. Rotating shaft; 9. Brush-type damping block. Detailed Implementation

[0024] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0025] like Figures 1 to 6 As shown, the present invention provides a variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials. The emergency descent device includes a housing 1, a rotating shaft 8, a descent mechanism, a winding assembly, and a damping assembly.

[0026] In this embodiment, the winding assembly includes a take-up shaft 2 and a rope 21. The take-up shaft 2 is rotatably mounted on a rotating shaft 8 via bearings, and the rope 21 is wound around the take-up shaft 2. One end of the rope 21 is fixed to the take-up shaft 2, and the other end is used to connect to the escaping personnel or the object to be lowered. When the personnel or object descends, the rope 21 drives the take-up shaft 2 to rotate. The rope is made of fiber rope, which allows for strength comparable to steel cables but with a smaller diameter.

[0027] Furthermore, the take-up shaft 2 includes a disc and a shaft. The disc is disc-shaped and is used to mount one end of the rope 21. The shaft is sleeved on the rotating shaft 8, and a bearing is provided between them. When the take-up shaft 2 rotates, the rotating shaft 8 does not rotate, and the rope 21 is wound around the shaft. There is a gap between the disc and the housing.

[0028] Furthermore, rope 21 is made of aramid fiber using a braiding process. Aramid fiber ropes offer significant advantages for descent devices, boasting a strength 5-6 times that of steel ropes of the same diameter. They exhibit exceptional load-bearing capacity and impact resistance, ensuring escape safety. In addition, aramid fiber can withstand temperatures up to 560℃ without melting, maintaining stable performance in fire scenarios. It is also resistant to acids and alkalis and exhibits anti-aging properties. Its density is only 1 / 5 that of steel, significantly reducing equipment weight, while also being wear-resistant and low-consumption, extending its service life.

[0029] In this embodiment, the descent mechanism includes a planetary carrier 4, planetary gears 5, a sun gear 6, and an internal gear 3. The planetary carrier 4 and the internal gear 3 are mounted on the rotating shaft 8, and bearings are respectively provided between the planetary carrier 4 and the internal gear 3 and the rotating shaft 8. The sun gear 6 is fixedly mounted on the rotating shaft 8.

[0030] In this embodiment, the planetary carrier 4 is provided with three supports 41, which are used to install three planetary gears 5 respectively. The planetary gears 5 are mounted on the planetary carrier 4 by pins, and the included angle between adjacent supports 41 is 60°. The internal gear 3 meshes with the three planetary gears 5, and the planetary gears 5 mesh with the sun gear 6.

[0031] In this embodiment, the internal gear 3 is connected to the shaft of the take-up shaft 2, with a disc fixedly mounted on one end of the shaft and the internal gear 3 fixedly connected to the other end.

[0032] In this embodiment, the gears are made of ultra-high molecular weight polyethylene (UHMWPE) using a compression molding process. UHMWPE gears offer significant advantages: extremely low coefficient of friction, resulting in minimal wear and noise during transmission, making them suitable for precision applications. They also exhibit strong impact resistance, are not easily broken by external impacts, and have a long service life. Furthermore, they are resistant to acids and alkalis, and corrosion, enabling stable operation in harsh environments. With a density only 1 / 8 that of steel, they are significantly lightweight, reducing the overall load and maintenance requirements of the equipment.

[0033] like Figure 2 and Figure 3 As shown, in this embodiment, the damping assembly is installed inside the housing 1. The damping assembly includes a brush-type damping block 9, a rotating blade 7, and a rotating cylinder 71. The rotating cylinder 71 is fixedly installed on the rotating shaft 8. The rotating cylinder 71 is provided with multiple slots 72, each slot 72 is arranged radially along the rotating cylinder 71, and the multiple slots 72 are evenly distributed along the circumference of the rotating cylinder 71. Preferably, six rotating blades 7 are provided.

[0034] like Figure 5 As shown, in this embodiment, the inner wall of the housing 1 is provided with multiple mounting grooves 11 along the circumferential direction, and multiple brush-type damping blocks 9 are provided. The brush-type damping blocks 9 are installed on the inner wall of the housing 1 by wedge-shaped buckles. The housing 1 is made of carbon fiber reinforced composite material. Compared with the metal shell, the fiber composite material shell is lighter in weight, and the molding process adopts liquid injection molding process.

[0035] like Figure 6 As shown, in this embodiment, the brush-type damping block 9 is made of rubber material and has a trapezoidal cross section. The stiffness of the damping block is changed by varying its thickness, which decreases from the outside to the inside.

[0036] like Figure 3 As shown, in this embodiment, the blade 7 is installed in the slot 72 of the rotating cylinder 71. The blade 7 and the rotating cylinder 71 are not directly connected, and a spring 73 is provided between the blade 7 and the rotating cylinder 71. The blade is made of carbon fiber reinforced composite material, which is less prone to corrosion compared to metal blades. The molding process adopts liquid injection molding.

[0037] In use, the damping assembly of this invention, influenced by the acceleration of the planetary gear 5, results in a faster descent speed, a higher rotational speed of the shaft 8, a greater centrifugal force, a longer extension of the blade 7 beyond the slot 72, and a greater resistance during rotation as the blade 7 strikes a position with higher stiffness in the brush damping block. Conversely, a slower descent speed, a slower rotational speed of the shaft 8, a smaller centrifugal force, and a shorter extension of the blade 7 due to the tension of the spring 73, resulting in a smaller resistance during rotation as the blade 7 strikes a position with lower stiffness in the brush damping block.

[0038] The emergency descent device of the present invention is designed with the following features to ensure the safe arrival of evacuees on the ground: (i) The damping force and load were dynamically matched. (1) Establish a damping force demand calculation model Based on a human body weight range of 30kg (children) to 150kg (extreme load), and combined with the laws of free fall motion, the minimum damping force required under different loads is derived. The formula is: in: The value is the body weight, ranging from 30 to 150 kg. The maximum safe descent speed is 1.5 m / s, in accordance with GB 21976.2-2012 standard. The damping force is applied at a distance of 0.8-1.2m, depending on the size of the decelerator housing. μ The coefficient of friction between the rope and the take-up spool (0.15-0.20). The acceleration due to gravity is 9.8 m / s².

[0039] Calculations show that the minimum damping force required for a 30kg load is 89.7N, and the minimum damping force required for a 150kg load is 448.5N. The damping force design range is determined to be 100-500N to meet the resistance requirements of the entire load range.

[0040] (2) Stiffness gradient optimization of brush-type damping blocks The brush-type damping block 9 adopts a three-section thickness gradient design: the thickness is 8-10mm on the side closest to the rotating cylinder 71 (inner layer), 12-15mm in the middle layer, and 18-22mm on the outer layer, corresponding to stiffnesses of 50-80N / mm, 120-150N / mm, and 200-250N / mm, respectively. By continuously varying the extension length of the rotating blade 7 (extension range 0-60mm), the damping force can be continuously adjusted from 100N to 500N, ensuring sufficient resistance under different loads.

[0041] (II) Design of the number of teeth and diameter of planetary gears (1) Derivation of gear module: Based on the torque requirements of the gear and the allowable stress of the material, the module is derived. The calculation formula is: in, The torque (N·mm) transmitted by the internal gear is derived from the load. The load factor is 1.2-1.4, taking into account impact load and transmission error. The face width factor is 0.8-1.2, depending on the structural space design. Number of teeth on the sun gear (design variable); Allowable bending stress for gear materials (after modification of ultra-high molecular weight polyethylene), .

[0042] Planetary gears are evenly distributed (angle 120°), transmission ratio The design is 5-8 (to ensure centrifugal force amplification effect), satisfying: in, The number of teeth on the sun gear. This represents the number of teeth on the internal gear.

[0043] (3) Gear pitch circle diameter: , d The pitch circle diameter of the gear; The gear module; This represents the number of teeth on the gear.

[0044] Example calculation (taking a 150kg extreme load as an example): The reel's disc radius is 40mm, and its ultimate damping force is... F d =500N, then T 1 = 20000 N·mm; take =1.3, =1.0, =32MPa, i=6; Substituting into the module formula, we can calculate the number of teeth on the sun gear: z1=20, M≈12; Number of teeth on the internal gear =100, pitch circle diameter d 2 = 1200mm; Number of teeth on the planetary gear z p =(z2−z1) / 2=50, pitch circle diameter d p =600mm.

[0045] The emergency descent device of this invention, when used for escape, first fixes the housing 1 to a fixed structure of a high-rise building (such as a window railing, fire hydrant interface, etc.) using a hanging ring, and securely connects the safety buckle at the end of the rope 21 to the safety belt of the escapee. When the escapee jumps out of the window and begins to descend, the weight of the body drives the rope downward, and the rope 21 drives the take-up shaft 2 to rotate. The take-up shaft 2 drives the internal gear 3 to rotate, and the internal gear 3 meshes with the planetary gear 5. The sun gear 6 is accelerated by the planetary gear 5, and the rotating shaft 8 rotates synchronously with the sun gear 6. The faster the descent speed, the faster the rotation speed of the rotating shaft 8, the greater the centrifugal force, the longer the extension length of the blade 7, and the greater the stiffness of the brush damping block when the blade 7 strikes it, resulting in greater resistance during rotation. Conversely, the slower the descent speed, the slower the rotation speed of the rotating shaft 8, the smaller the centrifugal force, and the shorter the extension length of the blade 7 due to the tension of the spring 73, resulting in less stiffness of the brush damping block when the blade 7 strikes it, resulting in less resistance during rotation. This slows down the descent until the escapees safely reach the ground, completing the descent process.

[0046] The above embodiments are merely preferred examples of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials, characterized in that, The device includes a housing, a rotating shaft, a descent mechanism, a rope, and a damping assembly. One end of the rope is used to connect to a load. The rotating shaft passes through the center of the housing, the descent mechanism, and the damping assembly. The rope drives the rotating shaft to rotate via the descent mechanism, which in turn drives the damping assembly to rotate. The descent mechanism includes a sun gear, an internal gear, and at least one planetary gear. The internal gear is driven by the rope, and the internal gear of the planetary gear meshes with the sun gear. The damping assembly includes at least one blade and a brush-type damping block. The blade generates centrifugal force as it rotates with the rotating shaft. The brush-type damping block is disposed on the rotation path of the blade. The brush-type damping block has a stiffness gradient that increases radially from the inside to the outside.

2. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 1, characterized in that, The take-up spool is rotatably mounted on the rotating shaft via bearings. The rope is wound around the take-up spool, with one end of the rope fixed to the take-up spool and the other end used to connect to the load.

3. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 2, characterized in that, The slow-descent mechanism includes an internal gear, a planetary carrier, planetary gears, and a sun gear. The planetary carrier and the internal gear are mounted on the rotating shaft, and bearings are respectively provided between the planetary carrier and the internal gear and the rotating shaft. The internal gear is connected to the take-up shaft, and the sun gear is fixedly mounted on the rotating shaft.

4. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 2, characterized in that, The planetary carrier is fixed on the rotating shaft. The planetary carrier has three supports, which are used to install three planetary gears respectively. The included angle between adjacent supports is 60°.

5. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 2, characterized in that, The damping assembly is installed inside the housing. The damping assembly includes a brush-type damping block, a rotating blade, and a rotating cylinder. The rotating cylinder is fixedly installed on the rotating shaft. The rotating cylinder has multiple slots, each slot is arranged radially along the rotating cylinder, and the multiple slots are evenly distributed circumferentially along the rotating cylinder.

6. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 1, characterized in that, The inner wall of the box is provided with multiple mounting grooves along the circumference, and multiple brush-type damping blocks are provided. The brush-type damping blocks are installed on the inner wall of the box by wedge-shaped buckles.

7. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 6, characterized in that, The stiffness of the brush-type damping block increases radially and is divided into an inner layer, a middle layer and an outer layer, with corresponding stiffnesses of 50-80 N / mm, 120-150 N / mm and 200-250 N / mm, respectively.

8. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 7, characterized in that, The emergency descent device also includes a dynamic matching design for damping force and load: (1) Establish a damping force demand calculation model Minimum damping force required for load range of 30kg-150kg. The formula is: in, This refers to the load weight; The maximum descent speed for safety; The stroke in which the damping force acts; μ The coefficient of friction between the rope and the take-up spool; It is the acceleration due to gravity; (2) Stiffness gradient optimization of brush-type damping blocks The brush-type damping block adopts a three-stage thickness gradient design: the inner layer is 8-10mm thick, the middle layer is 12-15mm thick, and the outer layer is 18-22mm thick, with corresponding stiffnesses of 50-80N / mm, 120-150N / mm, and 200-250N / mm, respectively.

9. The variable stiffness lightweight emergency descent device based on fiber-reinforced composite materials according to claim 7, characterized in that, The emergency descent device also includes the design of the number of teeth and diameter of the planetary gears: (1) Derivation of gear module: Gear module The calculation formula is: in, The torque transmitted by the internal gear is derived from the load. For load factor; This is the tooth width coefficient; This refers to the number of teeth on the internal gear. The allowable bending stress for gear material; (2) The planetary gears are evenly distributed, and the transmission ratio is... The design is 5-8, which satisfies: in, The number of teeth on the sun gear. This refers to the number of teeth on the internal gear. (3) Gear pitch circle diameter: , d The pitch circle diameter of the gear; The gear module; This represents the number of teeth on the gear.

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