A pure mechanical overspeed protection device based on ratchet cam link trip

Abstract

The utility model provides a kind of pure mechanical overspeed protection device based on ratchet wheel cam connecting rod tripping, including installation box, stroke reversing valve, main cam trigger mechanism and balance wheel impact mechanism, main cam trigger mechanism includes ratchet shaft, first cam and power torsional spring, and the outer circumferential body on the top end of ratchet shaft is vertically provided with clamping groove, and the vertex of first cam is connected with stroke reversing valve abutting;Balance wheel impact mechanism includes balance wheel shaft and impact balance wheel, and the inner end of impact balance wheel can be connected with the clamping groove buckle, so as to be tripped with clamping groove when its outer end is impacted by pendulum hammer, so that ratchet shaft and first cam are automatically rotated to open stroke reversing valve under the action of power torsional spring torsion force.The utility model is buckled linkage design by ratchet shaft and impact balance wheel, realizes mechanical automatic tripping trigger under overspeed working condition, cooperates standard stroke reversing valve to realize accurate action control, with the advantages of high structure standardization degree, action reliability is strong and maintenance is convenient.

Description

Technical Field

[0001] This utility model relates to a mechanical overspeed protection device for a water turbine, and more particularly to a purely mechanical overspeed protection device based on ratchet cam linkage disengagement. Background Technology

[0002] Currently used purely mechanical overspeed protection devices have several technical drawbacks. First, hydraulic valve components typically require non-standard R&D and customization or rely on imports, resulting in excessively long delivery cycles and difficulty in meeting urgent needs. Second, existing devices are prone to oil leakage and malfunction under high oil pressure conditions, severely impacting system reliability. Furthermore, traditional mechanical overspeed protection devices have complex structures, are difficult to maintain, and lack standardized design, increasing usage and maintenance costs.

[0003] In existing technologies, the linkage design between the tripping mechanism and the hydraulic valve in mechanical overspeed protection devices has significant shortcomings. On the one hand, it is difficult to balance tripping sensitivity with durability and reliability; on the other hand, the stroke control accuracy of the hydraulic valve is insufficient, which can easily lead to malfunctions. These problems severely restrict the performance improvement and application promotion of mechanical overspeed protection devices. Utility Model Content

[0004] The technical problem to be solved by this utility model is: to provide a purely mechanical overspeed protection device based on ratchet cam linkage release, which realizes the stroke ratio change of the stroke reversing valve through the ratchet cam linkage mechanism, thereby achieving linkage and unification with the release device.

[0005] To solve the above-mentioned technical problems, this utility model adopts the following technical solution:

[0006] A purely mechanical overspeed protection device based on ratchet cam linkage release includes a stroke reversing valve, a main cam triggering mechanism, and a balance wheel impact protection mechanism arranged sequentially at intervals on the top of the mounting box, wherein:

[0007] The main cam triggering mechanism includes a ratchet shaft rotatably mounted on the mounting box, a first cam and a power torsion spring respectively fixedly disposed at the upper and lower ends of the ratchet shaft, and a slot is vertically opened on the outer periphery of the top end of the ratchet shaft, and the vertex of the first cam abuts and connects with the stroke reversing valve.

[0008] The balance wheel impact mechanism includes a balance wheel shaft fixedly mounted on the mounting box and an impact-receiving balance wheel rotatably mounted on the top of the balance wheel shaft. The inner end of the impact-receiving balance wheel can be snapped into the slot so that it can disengage from the slot when its outer end is impacted by the pendulum, thereby causing the ratchet shaft and the first cam to automatically rotate under the torque of the power torsion spring to open the stroke reversing valve.

[0009] Preferably, the mounting box is a hollow square box structure with an open front and a switch door, and the stroke reversing valve, the main cam triggering mechanism, and the balance wheel impact mechanism are arranged sequentially from right to left on the top rear end side.

[0010] Preferably, the stroke reversing valve is a standard Rexroth stroke reversing valve, and one end of its valve core is connected to the outer peripheral wall and the corresponding vertex of the first cam through a roller to form a wheel-to-wheel point-to-point contact structure.

[0011] Preferably, the upper and lower ends of the ratchet shaft are rotatably mounted on the top plate and the floor of the mounting box via bearings, and a reset square shaft is fixedly provided at its top end;

[0012] The ratchet shaft is rotated by a wrench through the reset square shaft to store power for the power torsion spring, and the inner end of the impacted balance wheel is locked in the slot.

[0013] Preferably, one end of the power torsion spring is fixedly connected to the lower end of the ratchet shaft, and the other end is fixedly connected to a fixing block, wherein the fixing block is detachably mounted on the bottom plate of the mounting box using bolts.

[0014] Preferably, the main cam triggering mechanism further includes a first gear coaxially disposed in the middle of the ratchet shaft, the first gear being located at the top of the inner cavity of the mounting box and meshing with a second gear on the cam triggering mechanism.

[0015] Preferably, the main cam triggering mechanism further includes an angle limiting mechanism, which comprises a first limiting block and a second limiting block, wherein:

[0016] One end of the first limiting block is fixedly disposed on the outer side wall of the lower end of the ratchet shaft, and it can rotate with the ratchet shaft;

[0017] The second limiting block is detachably bolted to the base plate of the mounting box and is located on the rotation path of the second limiting block to limit the rotation angle of the ratchet shaft and the first cam on it to 60-120°.

[0018] Preferably, the impacted balance wheel is hinged to the hinge post at the top of the balance wheel shaft through a through hole in its middle, and the cross-section of its outer end is set as an ivory-shaped structure, while the cross-section of its inner end is set as a rectangular structure that can be locked with the slot.

[0019] Preferably, the balance wheel impact mechanism further includes a limiting shaft located on the swing path of the inner end of the impacted balance wheel, wherein:

[0020] The upper and lower ends of the limiting shaft are respectively fixedly installed on the top plate and bottom plate of the mounting box, and a limiting post is provided at its top end. A limiting groove corresponding to the limiting post is opened on the outer side of the inner end of the impacted swing wheel.

[0021] Preferably, the purely mechanical overspeed protection device further includes a cam-triggered mechanism and a limit switch spaced apart at the front top of the mounting box, wherein:

[0022] The cam triggering mechanism includes a driven shaft rotatably mounted on the mounting box and a second cam and a second gear respectively fixedly disposed at the upper end and middle of the driven shaft;

[0023] Furthermore, the apex of the second cam abuts against the limit switch, and the second gear meshes with the first gear on the main cam trigger mechanism.

[0024] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0025] This utility model provides a purely mechanical overspeed protection device based on ratchet cam linkage release. The ratchet cam linkage release mechanism consists of a main cam triggering mechanism and a swing wheel impact mechanism. Through the snap-lock linkage design between the ratchet shaft and the impacted swing wheel, it achieves automatic mechanical release triggering under overspeed conditions. Combined with a standard stroke reversing valve, it achieves precise action control. It has the advantages of high structural standardization, strong operational reliability, and convenient maintenance. Furthermore, with precise stroke setting of the cam, the purely mechanical overspeed hydraulic control valve can be configured with a standard Rexroth stroke reversing valve, eliminating the need for customized or specially imported mechanical overspeed valves. This makes the purely mechanical overspeed protection device highly adaptable, enabling universal standardized production to replace the original project-specific non-standard customization, greatly reducing the matching cycle and providing significant convenience for on-site maintenance and repair. Attached Figure Description

[0026] Figure 1 This is a three-dimensional structural diagram of a purely mechanical overspeed protection device based on ratchet cam linkage release according to this utility model. Figure 1 ;

[0027] Figure 2 This is a three-dimensional structural diagram of a purely mechanical overspeed protection device based on ratchet cam linkage release according to this utility model. Figure 2 ;

[0028] Figure 3 This is a cross-sectional view of a purely mechanical overspeed protection device based on ratchet cam linkage release according to the present invention.

[0029] Figure 4This is a longitudinal sectional view of a purely mechanical overspeed protection device based on ratchet cam linkage release according to the present invention.

[0030] Figure 5 This is a schematic diagram of the internal structure of a purely mechanical overspeed protection device based on ratchet cam linkage release according to this utility model;

[0031] Figure 6 This is a schematic diagram of the latching structure of the main cam triggering mechanism and the balance wheel impact mechanism in a purely mechanical overspeed protection device based on ratchet cam linkage release according to this utility model;

[0032] Figure 7 This is a three-dimensional structural diagram of a purely mechanical overspeed protection device based on ratchet cam linkage release in the release state according to this utility model;

[0033] Figure 8 This is a top view of the structure of a purely mechanical overspeed protection device based on ratchet cam linkage release in the released state according to this utility model.

[0034] The reference numerals in the attached drawings are as follows: 100-mounting box; 200-stroke reversing valve; 300-main cam triggering mechanism; 301-ratchet shaft; 302-slot; 303-first cam; 304-first gear; 305-power torsion spring; 306-fixed block; 307-first limit block; 308-second limit block; 309-reset square shaft; 400-balance wheel impact mechanism; 401-balance wheel shaft; 402-impacted balance wheel; 403-through hole; 404-hinge post; 405-limiting shaft; 406-limiting post; 407-limiting groove; 500-follower cam triggering mechanism; 501-follower shaft; 502-second cam; 503-second gear; 600-limit switch. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0036] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0037] In existing technologies, mechanical overspeed protection devices for water turbines generally use non-standard hydraulic valves or imported components, resulting in long delivery cycles, poor adaptability to high oil pressure, and problems such as oil leakage and malfunction. Traditional devices rely on customized hydraulic control systems, leading to maintenance difficulties and difficulty in matching standardized hydraulic components. Especially under high oil pressure conditions requiring rapid response, the linkage accuracy between the mechanical triggering mechanism and the hydraulic valve is difficult to guarantee.

[0038] To address these issues, researchers discovered a potential match between the stroke parameters of a standardized hydraulic valve and the motion trajectory of a mechanical triggering mechanism. However, two core challenges remained: how to construct a purely mechanical transmission structure to achieve stroke ratio control, and how to ensure precise synchronization between the triggering action and the opening and closing of the hydraulic valve. By analyzing the motion characteristics of the cam mechanism and the ratchet locking principle, a proposal was made to combine the ratchet release mechanism with a cam pushing structure. This utilizes a torsion spring for energy storage to achieve instantaneous drive, while a balance wheel structure transmits the impact force and enables rapid release.

[0039] In some of these embodiments, based on the above design concept, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 7 and Figure 8 As shown, this application proposes a purely mechanical overspeed protection device based on ratchet cam linkage release, mainly including a stroke reversing valve 200, a main cam triggering mechanism 300 and a swing wheel impact mechanism 400 arranged sequentially at intervals on the top of the mounting box 100. The main cam triggering mechanism 300 includes a ratchet shaft 301 rotatably mounted on the mounting box 100, a first cam 303 and a power torsion spring 305 respectively fixedly mounted on the upper and lower ends of the ratchet shaft 301. A groove 302 is vertically opened on the outer periphery of the top end of the ratchet shaft 301, and the apex of the first cam 303 abuts and connects with the stroke reversing valve 200. The balance wheel impact mechanism 400 includes a balance wheel shaft 401 fixedly mounted on the mounting box 100 and an impact-receiving balance wheel 402 rotatably mounted on the top of the balance wheel shaft 401. The inner end of the impact-receiving balance wheel 402 can be snapped into the slot 302 so that it can disengage from the slot 302 when its outer end is impacted by the pendulum, so that the ratchet shaft 301 and the first cam 303 automatically rotate under the torque of the power torsion spring 305 to open the stroke reversing valve 200.

[0040] The mounting box 100 is a rigid housing that supports the mechanical transmission components. Specifically, it can be a square box structure welded from steel plates. Its top has a mounting surface for fixing the stroke reversing valve 200, the triggering mechanism, and the impact-receiving mechanism. This structure provides a precise positioning reference for each component. The ratchet shaft 301 in the main cam trigger 300 is a rotating shaft with an axial groove at its top. It can be mounted between the top and bottom plates of the mounting box 100 via a bearing assembly. Its groove 302 structure is used to mechanically interlock with the impact-receiving swing wheel 402. The power torsion spring 305 is a helical spring sleeved on the lower end of the ratchet shaft 301. One end is fixed to the ratchet shaft 301, and the other end is connected to the bottom plate of the mounting box 100. This design provides a stable rotational driving force after the impact-receiving swing wheel 402 disengages. The impact-receiving balance wheel 402 in the balance wheel impact mechanism 400 refers to an oscillating component with an asymmetrical cross section. Its outer end adopts a streamlined cross section to withstand impact loads, and its inner end is provided with a rectangular protrusion that forms a planar contact with the slot 302 on the ratchet shaft 301. This structure can ensure static balance in the locked state.

[0041] Specifically, when the turbine experiences overspeed, the pendulum strikes the outer end of the impacted pendulum wheel 402, causing it to rotate around the pendulum wheel shaft 401. The rectangular protrusion at the inner end of the impacted pendulum wheel 402 disengages from the ratchet shaft groove 302. The elastic potential energy stored in the power torsion spring 305 drives the ratchet shaft 301 to rotate, which in turn drives the first cam 303 to push the valve core of the stroke reversing valve 200. The precise alignment design between the apex of the first cam 303 and the valve core roller allows the stroke reversing valve 200 to be fully opened by rotating the first cam 303 90 degrees. During this process, the rotation angle of the ratchet shaft 301 is constrained by the upper limit block of the mounting box 100 base plate, ensuring that the stroke reversing valve 200 reaches the predetermined opening degree. The instantaneous release of the mechanical interlock structure combined with the torsion spring drive enables the hydraulic valve to respond quickly.

[0042] Compared with existing technologies, traditional solutions rely on customized hydraulic valves and non-standard triggering mechanisms, resulting in poor adaptability and maintenance difficulties. This solution integrates a standard hydraulic valve into a mechanical triggering system through a ratchet cam linkage mechanism consisting of a main cam triggering mechanism 300 and a swing wheel impact mechanism 400, using a power torsion spring 305 to drive and replace the complex hydraulic control circuit. The impacted swing wheel 402 achieves rapid release while maintaining structural strength, and the wheel-to-wheel contact between the first cam (303) and the valve core roller reduces friction loss of the moving pair.

[0043] Through the above technical solutions, this application effectively solves the supply cycle problem caused by the poor compatibility of non-standard hydraulic valves, and reduces maintenance costs by adopting a standard stroke directional valve 200. The combination of a mechanical interlock structure and a torsion spring drive maintains triggering accuracy while avoiding the risk of oil leakage. The structural design of the front and rear ends of the impact-resistant swing wheel 402 balances impact resistance and agility, and the wheel-to-wheel contact method extends the service life of the components.

[0044] In some of these embodiments, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this application further proposes that the mounting box 100 is a hollow square box mechanism, with its front side set as an opening and equipped with a switch door, and the top rear end side is provided with a stroke reversing valve 200, a main cam triggering mechanism 300 and a balance wheel impact mechanism 400 arranged sequentially from right to left.

[0045] The square enclosure refers to a closed shell structure with a regular geometric shape, which can be achieved by welding or bolting metal sheets, forming a standardized installation space inside to accommodate various functional components. The front-opening structure refers to an openable maintenance access on the front of the enclosure, achieved through a hinged door panel, facilitating direct access to the internal core components for maintenance. The top and rear rear side layout, arranged from right to left, refers to the linear arrangement of functional modules along the length of the enclosure, forming a spatial layout that conforms to the mechanical transmission path.

[0046] Specifically, the square housing integrates the stroke reversing valve 200, the main cam triggering mechanism 300, and the balance wheel impact mechanism 400 through standardized internal space. The front opening structure, combined with the door design, allows maintenance personnel to perform component repairs without disassembling the entire device. The top and rear end layout places the contact points of the stroke reversing valve 200 and the main cam triggering mechanism 300 at the beginning of the transmission path, and the balance wheel impact mechanism 400 at the end of the action triggering, forming a continuous mechanical linkage spatial relationship. This layout constrains the motion trajectory of the ratchet cam linkage mechanism within a compact space, while reserving sufficient maintenance space for the front operating area.

[0047] In some of these embodiments, such as Figure 1 , Figure 2 and Figure 3 As shown, this application further proposes that the stroke reversing valve 200 adopts a standard Rexroth stroke reversing valve, and one end of its valve core is connected to the outer peripheral wall and corresponding vertex of the first cam 303 through a roller to form a wheel-to-wheel point-to-point contact structure.

[0048] The standard Rexroth directional valve refers to a standardized hydraulic valve conforming to international specifications, specifically implemented using standard Rexroth brand products. This feature addresses the issue of poor hydraulic valve compatibility by replacing non-standard customized valves with standardized components. The wheel-to-wheel point-to-point contact structure refers to the rolling contact between the roller mounted at the end of the valve core and the outer contour of the first cam 303. Specifically, a bearing-type roller can form a double-point contact with the cam apex and outer peripheral surface. This structure reduces motion resistance through rolling friction while utilizing the cam apex to trigger precise displacement.

[0049] Specifically, when the first cam 303 rotates under the drive of the ratchet shaft 301, its outer peripheral wall remains in contact with the valve core roller, causing the valve core to produce linear displacement. When the apex of the first cam 303 contacts the roller, the valve core reaches its maximum stroke position, triggering the reversing action. During this process, the roller rolls along the surface of the first cam 303, avoiding jamming caused by sliding friction. Since the stroke parameters of the standard valve are preset, the valve core stroke can be matched by adjusting the position of the apex of the first cam 303, without the need for custom valve body structure. For example, the height of the cam apex can be set to ±2.8mm corresponding to the stroke of the standard valve, so that the first cam 303 triggers the full stroke action precisely when it rotates 90 degrees.

[0050] Compared to existing technologies, traditional solutions using non-standard customized hydraulic valves require tailoring valve core stroke parameters to specific operating conditions, leading to extended production cycles. Furthermore, cam mechanisms employing sliding contact are prone to delays or jamming due to frictional resistance. This solution combines a standard Rexroth stroke-controlled directional valve with a rolling contact structure for the valve core, shortening the hydraulic valve's delivery cycle while ensuring operational reliability through the rolling friction mechanism.

[0051] Through the above technical solution, this application achieves the standardized application of hydraulic valve components, solving the problem of long delivery cycles caused by non-standard customization. The rolling contact structure between the valve core roller and the first cam 303 effectively reduces frictional loss of moving parts and avoids jamming during valve core operation. The dual-point contact design ensures stroke triggering accuracy while maintaining the continuity of the movement process, ensuring that the overspeed protection device can reliably trigger the hydraulic system shutdown action.

[0052] In some of these embodiments, such as Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, this application further proposes that the upper and lower ends of the ratchet shaft 301 are rotatably mounted on the top plate and floor of the mounting box 100 respectively via bearings, and a reset square shaft 309 is fixedly provided at its top end; a wrench is used to rotate the ratchet shaft 301 through the reset square shaft 309 to store power in the torsion spring 305, and the inner end of the impacted swing wheel 402 is manually rotated at a certain angle and locked into the slot 302. If necessary, an elegant box can be used to encase the top of the mounting box 100 or its exterior, leaving the reset square shaft 309 exposed on the upper side of the box. In use, only the reset square shaft 309 needs to be rotated, and the reset can be achieved with a wrench. The reset is very simple, the operation is convenient, and the structure is very simple and compact, with a beautiful appearance.

[0053] The bearing mounting structure refers to the use of rolling bearings to support the upper and lower ends of the ratchet shaft 301, specifically deep groove ball bearings or tapered roller bearings. The reset square shaft 309 is a square shaft segment rigidly connected to the top of the ratchet shaft 301, specifically a hexagonal head or square prism structure, its function being to provide a standard tool interface for applying external torque. The snap-fit ​​connection between the slot 302 and the inner end of the impact-resistant balance wheel 402 refers to the use of a mechanical locking structure to maintain the ratchet shaft in a stationary state, specifically achieved by a rectangular groove and a protruding structure, using geometric interlocking to ensure stable positioning before triggering.

[0054] Specifically, the top plate and floor of the mounting box 100 form a double-support structure through bearings, ensuring the stability of the ratchet shaft 301 during rotation. When reset is required, the operator inserts a standard wrench into the reset square shaft 309 and drives the ratchet shaft 301 to rotate clockwise. This rotation causes the power torsion spring 305 to undergo elastic deformation, storing mechanical energy. When the ratchet shaft 301 rotates to a predetermined angle, the inner end of the impacted pendulum wheel is manually inserted into the slot 302, or alternatively, the compression spring between the inner end of the impacted pendulum wheel 402 and the limiting shaft (405) automatically presses it into the slot 302, thus forming a mechanical locking state. At this time, the stored energy of the power torsion spring 305 and the constraint force of the impacted pendulum wheel 402 reach static equilibrium, putting the device in a ready-to-trigger state. The entire energy storage process does not require disassembly of the outer casing and is completed on a single operating surface using only external tools.

[0055] Through the above technical solution, this application realizes the rapid completion of the ratchet shaft 301 reset operation, solving the drawback of traditional mechanisms requiring disassembly and maintenance; it uses a standard tool interface to ensure the reliable storage of the power torsion spring 305; and it maintains the stable state before triggering through the mechanical interlock between the slot 302 and the inner end of the impacted balance wheel 402, while maintaining the compactness of the overall structure.

[0056] In some of these embodiments, such as Figure 3 and Figure 5 As shown, this application further proposes that one end of the power torsion spring 305 is fixedly connected to the lower end of the ratchet shaft 301, and the other end is fixedly connected to the fixing block 306, and the fixing block 306 is detachably mounted on the base plate of the mounting box 100 by bolts.

[0057] The detachable bolt installation refers to the use of bolts to form a detachable rigid connection between the fixing block 306 and the base plate of the mounting box 100. This structure ensures that the fixing block 306 does not shift during operation, while allowing for quick disassembly by loosening the bolts. The fixing block 306 is a metal component used to fix and support the end of the power torsion spring 305. Specifically, it can be implemented using an L-shaped steel plate with a spring hook. Its bottom plane contacts the base plate of the mounting box, forming a stable support surface and preventing deflection of the torsion spring during operation.

[0058] Specifically, the end of the power torsion spring 305 is connected to the fixing block 306 via a hook structure. The fixing block 306 is locked in place by bolts passing through its mounting holes and corresponding threaded holes on the base plate. When maintenance is required, the fixing block can be removed and its position adjusted by loosening the bolts. In operation, the engagement of the fixing block 306 and the slot 302 together resists the alternating torque generated by the power torsion spring 305, preventing the fixing block 306 from shifting.

[0059] In some of these embodiments, such as Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the application further proposes that the main cam triggering mechanism 300 also includes a first gear 304 coaxially disposed in the middle of the ratchet shaft 301. The first gear 304 is located at the top of the inner cavity of the mounting box 100 and is meshed with a second gear 503 on the cam triggering mechanism 500.

[0060] The first gear 304 is a transmission component coaxially fixed with the ratchet shaft 301, which can be implemented as a spur gear and is connected to the ratchet shaft 301 via a key to achieve synchronous rotation. The first gear 304 is axially positioned at the middle of the ratchet shaft 301, ensuring that its meshing surface with the second gear 503 is located in the top space of the inner cavity of the mounting box 100. The second gear 503 is a driven component that meshes with the first gear 304, and can be the same spur gear, fixed to the driven shaft via a key connection.

[0061] Specifically, when the ratchet shaft 301 rotates under the drive of the power torsion spring 305, the first gear 304, which is fixed coaxially with it, rotates synchronously. Since the first gear 304 and the second gear 503 form a 1:1 meshing transmission relationship, the driven shaft 501 and its second cam 502 will generate rotational motions of equal angle and direction. The rigid meshing of the two gears eliminates the phase difference during transmission, ensuring that the action of triggering the first cam 303 to open the stroke reversing valve 200 and the action of triggering the second cam 502 to press the stroke switch 600 are completely synchronized in time and displacement.

[0062] Compared to existing technologies, the synchronization of master and slave mechanisms in traditional overspeed protection devices typically relies on independent drive sources or electronic signal coordination, which carries the risk of response delays and asynchronous actions. This solution, however, achieves rigid synchronization of the master and slave mechanisms through a mechanical linkage via gear meshing, driven by a single power source, eliminating potential signal transmission errors caused by electrical components.

[0063] Through the above technical solution, this application achieves synchronous triggering of the stroke reversing valve 200 and the limit switch 600, enabling the two key actions of hydraulic system shutdown and electrical signal transmission to be completed simultaneously in the mechanical transmission chain. The meshing transmission of the two gears transmits the rotation angle of the main cam triggering mechanism 300 to the slave cam triggering mechanism 500 without loss, ensuring that the two actuators maintain consistent operation during overspeed protection, thereby improving the overall reliability of the system.

[0064] Furthermore, in some of these embodiments, such as Figure 3 and Figure 4 As shown, this application further proposes a main cam triggering mechanism 300 including an angle limiting mechanism, which includes a first limiting block 307 and a second limiting block 308. One end of the first limiting block 307 is fixed to the outer wall of the lower end of the ratchet shaft 301 and rotates with the shaft; the second limiting block 308 is detachably mounted on the base plate of the mounting box 100 by bolts and is located on the rotation path of the first limiting block 307, for limiting the rotation angle of the ratchet shaft 301 and the first cam 307 to the range of 60-120°, preferably to 90°.

[0065] The first limiting block 307 is a rotating reference component rigidly connected to the ratchet shaft 301. It can be fixed to the shaft surface by welding a metal block or bolting, and its rotation trajectory forms an angle monitoring reference. The second limiting block 308 is a blocking component statically installed at the bottom of the housing. It can be a metal block with threaded holes fixed with bolts. By adjusting the installation position, the blocking contact point is changed, thereby adjusting the rotation angle threshold. The detachable installation structure allows for repositioning of the second limiting block 308 by removing the bolts, enabling on-site adjustment of the limiting angle.

[0066] Specifically, when the ratchet shaft 301 is driven to rotate by the power torsion spring 305, the first limiting block 307 rotates synchronously with the shaft. When it rotates to a set angle, the end of the first limiting block 307 makes physical contact with the second limiting block 308, forming a mechanical block. This rigid limiting method directly achieves motion cutoff through the collision of metal parts, avoiding control deviations caused by deformation of elastic elements or sensor failure. The second limiting block 308 is fixed to the threaded hole array in the base plate by bolts. The operator can change the blocking position by selecting different mounting hole positions, for example, adjusting the limiting angle to 90° or 120° to adapt to the stroke requirements of different stroke reversing valves 200.

[0067] Through the above technical solution, this application achieves precise mechanical control of the rotation angle of the ratchet shaft 301, ensuring that the power torsion spring 305 effectively drives the cam to trigger the stroke reversing valve 200, while preventing gear misalignment or mechanism damage caused by excessive rotation. Furthermore, the adjustable limit mechanism achieves adjustable limit angle through the cooperation of the detachably mounted second limit block 308 and the threaded hole array. Simultaneously, the integrated design of the first limit block 307 and the ratchet shaft 301 avoids assembly errors and ensures angle control accuracy.

[0068] In some of these embodiments, such as Figure 2 , Figure 6 , Figure 7 and Figure 8 As shown, this application further proposes that the impacted balance wheel 402 is hinged to the hinge post 404 at the top of the balance wheel shaft 401 through the through hole 403 in its middle, and the cross-section of its outer end is set as an ivory-shaped structure, and the cross-section of its inner end is set as a rectangular structure that can be locked with the slot 302.

[0069] The ivory-shaped structure refers to an outer cross-section with a streamlined profile resembling ivory, which can be achieved using a combination of circular arcs and straight lines. This structure optimizes the impact force transmission path during pendulum impact. The rectangular structure refers to an inner cross-section with a regular rectangular profile, which can be achieved using right-angled sides and a planar contact surface. This structure increases the contact area with the slot through planar contact, forming a rigid locking constraint. The hinge post 404 refers to a cylindrical protrusion located at the top of the balance wheel shaft 401, which can be achieved using an interference fit or a pin connection.

[0070] Specifically, when the impact-bearing balance wheel 402 is in the ready-to-trigger state, the rectangular plane at its inner end forms a surface contact and locks with the corresponding plane of the ratchet shaft groove 302. When the outer end of the impact-bearing balance wheel 402 is struck by the pendulum, the impact-bearing balance wheel 402 is driven to rotate around the hinge post 404, and the rectangular contact surface slides along the plane of the groove 302 to disengage. During the disengagement process, the frictional resistance torque of the planar contact is less than the driving torque of the power torsion spring 305, so that the disengagement action is completed instantaneously. During reset, the ratchet shaft 301 is rotated in the opposite direction to realign the plane of the groove 302 with the inner end plane of the impact-bearing balance wheel 402, and the self-centering characteristic of the planar contact is used to achieve precise reset.

[0071] Furthermore, in some of these embodiments, such as Figure 2 , Figure 6 , Figure 7 and Figure 8As shown, this application further proposes that the balance wheel impact mechanism 400 also includes a limiting shaft 405 located on the swing path of the inner end of the impacted balance wheel 402. The upper and lower ends of the limiting shaft 405 are respectively fixedly mounted on the top plate and bottom plate of the mounting box 100. A limiting post 406 is provided at its top end, and a limiting groove 407 corresponding to the limiting post 406 is provided on the outer side of the inner end of the impacted balance wheel 402.

[0072] The limiting shaft 405 is a rigid support structure perpendicular to the top and bottom plates of the mounting box 100. It can be implemented by welding or bolting a metal cylinder to the mounting box, and is used to limit the swing range of the impacted pendulum wheel 402. The limiting post 406 is a protruding structure at the top of the limiting shaft 405, used to cooperate with the limiting recess 407 to form a limiting constraint. The limiting groove 407 is an arc-shaped groove structure formed on the outer side of the inner end of the impacted pendulum wheel 402. It can be machined to form a groove matching the diameter of the limiting post 406, and is used to limit the sliding trajectory of the limiting post during swing.

[0073] Specifically, when the impacted balance wheel 402 rotates due to disengagement, the limiting groove 407 on the outer side of its inner end swings towards the limiting post 406 at the top of the limiting shaft 405. The contact surface between the limiting post 406 and the limiting groove 407 forms a mechanical guide, limiting the swing angle of the impacted balance wheel 402 within a preset range. Since the upper and lower ends of the limiting shaft 405 are fixed to the top and bottom plates of the mounting box 100, its rigid support can prevent displacement during swinging. After the impacted balance wheel 402 completes the disengagement action, the cooperation between the limiting groove 407 and the limiting post 406 stops it in a predetermined position, preventing excessive swinging due to inertia.

[0074] In some of these embodiments, such as Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, this application further proposes that the purely mechanical overspeed protection device also includes a cam triggering mechanism 500 and a limit switch 600 spaced apart at the top front side of the mounting box 100. The cam triggering mechanism 500 includes a driven shaft 501 rotatably mounted on the mounting box 100 and a second cam 502 and a second gear 503 respectively fixedly mounted on the upper end and middle of the driven shaft 501. The apex of the second cam 502 abuts against the limit switch 600, and the second gear 503 meshes with the first gear 304 on the main cam triggering mechanism 300.

[0075] The cam triggering mechanism 500 is an auxiliary execution unit that transmits power to the main cam triggering mechanism 300 via gear meshing. Specifically, it can be implemented using a coaxially mounted second cam 502 and second gear 503. The second cam 502 triggers the limit switch 600, and the second gear 503 receives the rotational power from the main cam triggering mechanism. The limit switch 600 is a triggering device for sending electrical signals, which can be implemented using a micro switch or proximity switch. Its contacts form an abutment relationship with the apex of the second cam 502, and the displacement generated by the cam rotation triggers the switch action. The master-slave gear meshing refers to a mechanical connection method that transmits rotational power through a gear pair, which can be implemented using spur gears. The gear ratio of the first gear 304 to the second gear 503 is set to 1:1 to ensure synchronous rotation of the two cams.

[0076] Specifically, when the ratchet shaft 301 in the main cam triggering mechanism 300 is driven to rotate by the power torsion spring 305, the first gear 304 drives the second gear 503 to rotate synchronously, causing the second cam 502 on the driven shaft 501 to generate a rotational displacement equal to that of the first cam 303. During rotation, the apex of the second cam 502 applies pressure to the limit switch 600, triggering its contact switching state. Thus, while the limit reversing valve 200 is opened by the first cam 303, the limit switch 600 simultaneously outputs an electrical signal. The meshing connection of the master and driven gears distributes a single power source to two sets of actuators. The transmission accuracy of the gear pair ensures the consistency of the rotation angles of the two cams, avoiding time differences caused by independent drives.

[0077] Through the above technical solutions, this application achieves millisecond-level synchronization between hydraulic valve reversing control and electrical signal triggering, solving the system misjudgment problem caused by the asynchrony between mechanical action and electrical feedback; the transmission structure is simplified by master-slave gear meshing, and the drive components of the two actuators are integrated on the same axis, reducing assembly complexity; the use of gear pair transmission instead of split linkage mechanism avoids friction loss caused by multi-stage transmission and improves the reliability of action.

[0078] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0079] Secondly, the accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

[0080] Finally, the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A purely mechanical overspeed protection device based on ratchet cam linkage release, characterized in that, The mounting box (100) includes a stroke reversing valve (200), a main cam triggering mechanism (300), and a balance wheel impact mechanism (400) arranged sequentially at intervals on the top of the mounting box (100), wherein: The main cam triggering mechanism (300) includes a ratchet shaft (301) rotatably mounted on the mounting box (100), a first cam (303) and a power torsion spring (305) respectively fixedly disposed on the upper and lower ends of the ratchet shaft (301), and a slot (302) is vertically provided on the outer periphery of the top end of the ratchet shaft (301), and the vertex of the first cam (303) abuts against the stroke reversing valve (200); The balance wheel impact mechanism (400) includes a balance wheel shaft (401) fixedly mounted on the mounting box (100) and an impact-receiving balance wheel (402) rotatably mounted on the top of the balance wheel shaft (401). The inner end of the impact-receiving balance wheel (402) can be snapped into the slot (302) so that it can disengage from the slot (302) when its outer end is impacted by the pendulum, so that the ratchet shaft (301) and the first cam (303) automatically rotate under the torque of the power torsion spring (305) to open the stroke reversing valve (200).

2. The purely mechanical overspeed protection device according to claim 1, characterized in that, The mounting box (100) is a hollow square box mechanism with an open front and a switch door. The stroke reversing valve (200), the main cam triggering mechanism (300) and the balance wheel impact mechanism are arranged sequentially from right to left on the top rear end side.

3. The purely mechanical overspeed protection device according to claim 1, characterized in that, The stroke reversing valve (200) adopts a standard Rexroth stroke reversing valve. One end of its valve core is connected to the outer peripheral wall and corresponding vertex of the first cam (303) through a roller, forming a wheel-to-wheel point-to-point contact structure.

4. The purely mechanical overspeed protection device according to claim 1, characterized in that, The upper and lower ends of the ratchet shaft (301) are rotatably mounted on the top plate and the floor of the mounting box (100) respectively via bearings, and a reset square shaft (309) is fixedly provided at its top end. The ratchet shaft (301) is rotated by a wrench through the reset square shaft (309) to store power for the power torsion spring (305) and to lock the inner end of the impacted pendulum wheel (402) into the slot (302).

5. The purely mechanical overspeed protection device according to claim 1, characterized in that, One end of the power torsion spring (305) is fixedly connected to the lower end of the ratchet shaft (301), and the other end is fixedly connected to the fixing block (306), and the fixing block (306) is detachably mounted on the base plate of the mounting box (100) by bolts.

6. The purely mechanical overspeed protection device according to claim 1, characterized in that, The main cam triggering mechanism (300) further includes a first gear (304) coaxially disposed in the middle of the ratchet shaft (301). The first gear (304) is located at the top of the inner cavity of the mounting box (100) and meshes with a second gear (503) on the cam triggering mechanism (500).

7. The purely mechanical overspeed protection device according to claim 1, characterized in that, The main cam triggering mechanism (300) further includes an angle limiting mechanism, which comprises a first limiting block (307) and a second limiting block (308), wherein: One end of the first limiting block (307) is fixedly disposed on the outer side wall of the lower end of the ratchet shaft (301), and it can rotate with the ratchet shaft (301); The second limiting block (308) is detachably bolted to the base plate of the mounting box (100) and is located on the rotation path of the second limiting block (308) to limit the rotation angle of the ratchet shaft (301) and the first cam (303) thereon to 60-120°.

8. The purely mechanical overspeed protection device according to claim 1, characterized in that, The impacted balance wheel (402) is hinged to the hinge post (404) at the top of the balance wheel shaft (401) through the through hole (403) in its middle part, and the cross-section of its outer end is set as an ivory-shaped structure, and the cross-section of its inner end is set as a rectangular structure that can be locked with the slot (302).

9. The purely mechanical overspeed protection device according to claim 1, characterized in that, The balance wheel impact mechanism (400) further includes a limiting shaft (405) located on the swing path of the inner end of the impacted balance wheel (402), wherein: The upper and lower ends of the limiting shaft (405) are respectively fixedly installed on the top plate and bottom plate of the mounting box (100), and a limiting post (406) is provided at its top end. A limiting groove (407) corresponding to the limiting post (406) is provided on the outer side of the inner end of the impacted swing wheel (402).

10. The purely mechanical overspeed protection device according to claim 1, characterized in that, It also includes a cam-triggered mechanism (500) and a limit switch (600) spaced apart at the front top of the mounting box (100), wherein: The cam triggering mechanism (500) includes a driven shaft (501) rotatably mounted on the mounting box (100) and a second cam (502) and a second gear (503) respectively fixedly disposed on the upper end and the middle of the driven shaft (501). The apex of the second cam (502) abuts against the limit switch (600), and the second gear (503) meshes with the first gear (304) on the main cam trigger mechanism (300).

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