Overrun protection safety and construction hoist

Abstract

The application relates to overspeed protection safety device and construction hoist. The overspeed protection safety device comprises a main shaft capable of being rotationally supported and a braking device, wherein the braking device comprises a centrifugal seat sleeved on the outer surface of the main shaft and a speed limiting spring, the centrifugal seat is provided with at least two radial side holes uniformly distributed in the circumferential direction, one braking block is radially movably embedded in each side hole, and the speed limiting spring applies a radial clamping force to the braking block. The braking device further comprises two centrifugal seat baffles, the centrifugal seat baffles are respectively sleeved on the shaft shoulders of the main shaft located on the axial two sides of the centrifugal seat with their inner holes and are fixedly connected with the centrifugal seat.

Description

[0001] This application is a divisional application of Chinese patent application 202410014904.3, filed on January 5, 2024, entitled "Overspeed protection safety device and construction hoist". Technical Field

[0002] This application relates to an overspeed protection safety device and a construction hoist having said overspeed protection safety device. Background Technology

[0003] Overspeed protection safety devices are one of the most important safety devices in construction machinery. When the operating speed of the equipment reaches the preset protection speed of the overspeed protection safety device, the overspeed protection safety device will be triggered to decelerate and brake the construction machinery to prevent accidents.

[0004] Chinese invention patent CN 111776906 B and Chinese utility model patent CN 212799169 U respectively disclose an overspeed protection safety device. The overspeed protection safety device includes a rotatably supported main shaft and a speed regulating device. The speed regulating device includes a centrifugal seat fitted onto the outer surface of the main shaft, a centrifugal shaft installed in a side hole of the centrifugal seat, a disc spring and a centrifugal block fitted onto the end of the centrifugal shaft, friction plates bonded to the outer surface of the centrifugal block, a brake drum installed between the large end cover and the tail end cover, and a speed regulating spring clamped to the outer ring of the centrifugal block. In the prior art, the centrifugal seat is one of the core components of the overspeed protection safety device, and it needs to perform multiple functions. For example, it needs to limit the axial displacement of the centrifugal seat relative to the main shaft, and also limit the maximum value of the rotation angle of the centrifugal seat relative to the main shaft. Furthermore, the centrifugal seat needs to simultaneously accommodate the centrifugal shaft and the centrifugal block and guide their movement, preventing the centrifugal shaft and the centrifugal block from rotating, tilting, or swaying within the centrifugal seat, so that the friction plates can fully conform to the brake drum, thereby generating and transmitting a sufficiently large braking torque. If the overspeed protection safety device has a microswitch, the centrifuge holder must also be able to trigger the microswitch by its rotation relative to the spindle. All these functions require the centrifuge holder to be relatively large in size and its structure to be complexly machined, making the manufacturing process of the centrifuge holder very complex and costly. When the centrifuge holder wears out or is damaged, the entire centrifuge holder must be replaced, which is also very uneconomical. Summary of the Invention

[0005] Therefore, one aspect of this application is to provide an overspeed protection safety device, the overspeed protection safety device comprising: a rotatably supported spindle; and a braking device, wherein the braking device comprises a centrifugal seat fitted onto the outer surface of the spindle and a speed limiting spring, wherein the centrifugal seat has at least two radially distributed side holes evenly arranged in the circumferential direction, a brake block is radially movable and embedded in each of the side holes, and the speed limiting spring applies a radial clamping force to the brake block, so that in the initial unbraked state of the overspeed protection safety device, the radially inner end of the brake block is embedded in a corresponding groove on the outer surface of the spindle, thereby the brake block and the centrifugal seat can rotate synchronously with the spindle. The braking device includes two centrifugal seat baffles. The baffles, with their inner holes, are respectively fitted onto the shoulders of the main shaft located on both sides of the centrifugal seat axially and are fixedly connected to the centrifugal seat, thereby preventing axial movement of the centrifugal seat on the main shaft. The inner contour of the inner hole of the baffle and the outer contour of the shoulder have a mutually cooperating rotation limiting structure. This rotation limiting structure limits the maximum angle of rotation of the baffle, together with the centrifugal seat, relative to the main shaft from the initial unbraked state of the overspeed protection safety device. Therefore, it is no longer necessary to machine structures on the centrifugal seat to prevent axial movement of the centrifugal seat on the main shaft, or structures to limit the rotation angle of the centrifugal seat and thus the brake block relative to the main shaft. These measures simplify the manufacturing of the centrifugal seat and reduce its cost.

[0006] Optionally, each brake block is equipped with an independent speed-limiting spring. Alternatively, a single speed-limiting spring is provided, which is mounted in a full circle around the radial outer surface of the brake block.

[0007] Optionally, the braking block includes a centrifugal shaft located radially inward and a compression spring and a centrifugal block sequentially fitted onto a section of the centrifugal shaft extending radially outward from the side hole of the centrifugal seat. The radially inner end of the centrifugal shaft forms the radially inner end of the braking block, and the radially outer end of the centrifugal block forms the radially outer end of the braking block. During braking, the compression spring can be compressed by the centrifugal shaft, thereby providing a gradually increasing positive pressure to the centrifugal block. Further optionally, each centrifugal block abuts against the corresponding side surface of an adjacent centrifugal seat baffle on both axial sides, allowing the centrifugal block to slide on the corresponding side surface of the centrifugal seat baffle without tilting or swaying during radial movement. Further optionally, each centrifugal block is equipped with guide pins on both axial sides, the guide pins being embedded in radial guide grooves or guide holes in adjacent centrifugal seat baffles, allowing the centrifugal block to move radially relative to the centrifugal seat baffle without rotation. Optionally, the compression spring is a disc spring. When a guide hole is provided in the centrifuge seat baffle, the radial outward movement distance of the centrifuge block can be further limited by appropriately selecting the position of the radially outer end of the guide hole. This limits the stroke of the compression spring along the main shaft's radial compression and ultimately limits the maximum braking force of the overspeed protection safety device. Through these measures, the centrifuge seat no longer needs to accommodate and guide the centrifuge block, but only the centrifuge shaft; the accommodation and guidance of the centrifuge block are undertaken by the centrifuge seat baffle. Therefore, compared to the prior art, the radially outer dimension of the centrifuge seat can be designed to be smaller, and it is no longer necessary to machine a structure in the centrifuge seat to accommodate and guide the centrifuge block. Thus, the manufacturing of the centrifuge seat is further simplified, and the cost of the centrifuge seat is further reduced.

[0008] The spindle has a first end for mounting a gear and a second end away from the gear. Optionally, a microswitch triggering structure is provided at the second end of the spindle. The microswitch triggering structure includes a first microswitch trigger pin and a second microswitch trigger pin. The first microswitch trigger pin is at least partially inserted axially into an axial hole in the end face of the second end of the spindle, and the second microswitch trigger pin is partially inserted radially into a radial hole in the side face of the second end of the spindle. The axial hole and the radial hole intersect at their inner ends, thereby allowing the first and second microswitch trigger pins to interact with each other such that radial inward movement of the second microswitch trigger pin causes axial outward movement of the first microswitch trigger pin, and vice versa. Optionally, the end of the second microswitch trigger pin extending from the main shaft rests in a guide groove within the inner hole of a centrifugal seat baffle near the second end of the main shaft. The inner contour of the guide groove allows the second microswitch trigger pin to be pressed radially inward from its initial position by the inner contour of the guide groove when the centrifugal seat baffle rotates relative to the main shaft. This causes the first microswitch trigger pin to move axially outward and trigger the microswitch. Optionally, the microswitch triggering structure includes a microswitch trigger spring that axially presses the first microswitch trigger pin inward. After braking is complete, by reversing the main shaft, the first microswitch trigger pin can move axially inward under the action of the microswitch trigger spring, and the second microswitch trigger pin moves radially outward to its initial position under the action of the first microswitch trigger pin, thereby releasing the triggering state of the microswitch. Optionally, the microswitch triggering structure includes a second limiting pin to prevent the second microswitch trigger pin from dislodging from the radial hole of the main shaft. Through the above measures, it is unnecessary to fabricate a structure for triggering the microswitch in the centrifuge holder. Therefore, the manufacturing of the centrifuge holder is further simplified and its cost is further reduced.

[0009] Optionally, the outer surface of the spindle has a cam curve, wherein the diameter of the cam curve gradually increases as it moves away from the groove of the spindle along the circumferential direction. Further optionally, when the spindle speed exceeds a predetermined speed threshold, the brake block, under centrifugal force, overcomes the clamping force of the speed-limiting spring and is thrown out of the groove of the spindle. A friction pad located at the radially outer end of the brake block contacts and rubs against a brake drum fixedly mounted around the centrifugal seat to generate a braking torque. Under the action of this braking torque, the radially inner end of the brake block can move from the groove of the spindle to the cam curve, and the centrifugal seat follows the brake block and can rotate relative to the spindle until the angle of rotation of the centrifugal seat relative to the spindle reaches its maximum value, thus the centrifugal seat and the spindle rotate synchronously until they stop. Further optionally, after braking is completed, the radially inner end of the brake block falls back into the groove of the spindle along the cam curve by reversing the spindle, thereby achieving automatic reset of the overspeed protection safety device.

[0010] One aspect of this application is to provide a construction hoist having an overspeed protection safety device as described above, wherein a gear is mounted on the first end of the main shaft of the overspeed protection safety device, and the gear meshes with a rack fixedly mounted on the guide rail frame of the construction hoist. Attached Figure Description

[0011] The accompanying drawing illustrates a preferred embodiment of the overspeed protection safety device of this application, wherein: Figure 1 For overspeed protection safety device along Figure 2 A sectional view of the section line AA in the diagram; Figure 2 For overspeed protection safety device along Figure 1 A sectional view of the section line BB in the diagram; Figure 3 For overspeed protection safety device along Figure 1 A sectional view of the section line CC in the diagram; Figure 4 For overspeed protection safety devices in the braking state, the following applies: Figure 1 The sectional view of the section line BB in the diagram.

[0012] Reference numerals in the attached drawings: 1. Main shaft; 2. First bearing; 3. Centrifuge seat baffle; 4. Centrifuge seat; 5. First retaining ring; 6. Guide pin; 7. Disc spring; 8. Speed ​​limiting spring; 9. Friction plate; 10. Centrifuge block; 11. Brake drum; 12. Centrifuge shaft; 13. First limit pin; 14. Second bearing; 15. Switch sleeve; 16. Micro switch; 17. Inner end cover; 18. Second retaining ring; 19. Micro switch trigger spring; 20. First micro switch trigger pin; 21. Second limit pin; 22. Second micro switch trigger pin; 23. Oil seal; 24. Outer end cover; 25. Gear. Detailed Implementation

[0013] A preferred embodiment of this application will be further described in detail below with reference to the accompanying drawings, but this application is not limited to the preferred embodiment shown.

[0014] like Figure 1 As shown, the overspeed protection safety device includes a main shaft 1, a switch sleeve 15, an inner end cover 17, a brake drum 11, an outer end cover 24, and a gear 25. The main shaft 1 is rotatably supported in the overspeed protection safety device and has a first end for mounting the gear 25 and a second end away from the gear 25. Figure 1In the illustrated embodiment, the main shaft 1 is supported, for example, by a first bearing 2 and a second bearing 14 in the inner end cover 17 and the outer end cover 24, respectively. The main shaft 1 and the gear 25 are connected in a way that prevents relative rotation, for example, by a key or any other suitable means, so that the rotation of the gear 25 can drive the rotation of the main shaft 1. One end of the inner end cover 17 is fixedly connected to the brake drum 11, for example, by a screw or any other suitable means, and the other end is fixedly connected to the switch sleeve 15, for example, by a screw or any other suitable means. A micro switch 16 is installed on the left end of the inner end cover 17, and an oil seal 23 is installed on the right end of the brake drum 11 near the second bearing 14. The overspeed protection safety device is provided with a braking device, which includes: a centrifugal seat 4 fitted on the outer surface of the main shaft 1, centrifugal seat baffles 3 located on both axial sides of the centrifugal seat 4, a brake block, a friction plate 9 disposed at the radially outer end of the brake block, a brake drum 11 fixedly installed around the centrifugal seat 4, and a speed limiting spring 8. The centrifugal seat 4 has at least two radially distributed side holes along the circumferential direction. A brake block is radially movable and embedded in each side hole, and the speed limiting spring 8 applies a radial clamping force to the brake block. Thus, in the initial unbraked state of the overspeed protection safety device, the radially inner end of the brake block is embedded in a corresponding groove on the outer surface of the main shaft 1, thereby allowing the brake block and the centrifugal seat 4 to rotate synchronously with the main shaft 1. In the illustrated embodiment, the centrifugal seat 4 has three circumferentially distributed side holes, and three brake blocks are thus provided. However, the overspeed protection safety device of this application is not limited to three side holes and three brake blocks, but can have only two side holes and two brake blocks. Of course, depending on the braking power requirements and the size of the overspeed protection safety device, the overspeed protection safety device of this application can have four or more side holes and brake blocks.

[0015] like Figure 1 and 2 Clearly shown, the centrifuge seat 4 is fitted around the outer ring of the main shaft 1, and the centrifuge seat baffle 3 is fixedly connected to the centrifuge seat 4, for example, by screws or any other suitable means. The shoulders of the main shaft 1 located on both axial sides of the centrifuge seat 4 are respectively embedded in the inner holes of the centrifuge seat baffle 3, thereby preventing the centrifuge seat 4 from moving axially on the main shaft 1. Figure 2As shown, three braking blocks are evenly distributed circumferentially around the central axis of the centrifuge seat 4. Each braking block is radially movable and embedded in a corresponding side hole of the centrifuge seat 4. The radially inner end of the braking block, or preferably a protrusion on the end face of the radially inner end of the braking block, is embedded in a corresponding groove on the outer surface of the main shaft 1. The braking block can be a one-piece component. However, to further improve the gradual increase of braking force during braking, the braking block can be a multi-piece component, including a centrifuge shaft 12 located radially inward and a compression spring and a centrifuge block 10 sequentially fitted onto the radially outward section of the centrifuge shaft 12 extending from the side hole of the centrifuge seat 4. The radially inner end of the centrifuge shaft 12 forms the radially inner end of the braking block, and the radially outer end of the centrifuge block 10 forms the radially outer end of the braking block. In the embodiment shown in the figure, the compression spring is a disc spring 7, and a first retaining ring 5 is additionally fitted between the centrifugal shaft 12 and the disc spring 7. The friction plate 9 is bonded to the radial outer end of the centrifugal block 10, and the speed limiting spring 8 is mounted in a full circle on the outer surface of the centrifugal block 10. However, as an alternative, there can be multiple speed limiting springs 8, that is, an independent speed limiting spring 8 is provided for each brake block. When the centrifugal shaft 12 has a circular cross-section, in order to limit the rotation of the centrifugal shaft 12, a first limiting pin 13 can be fixed in the pin hole of the centrifugal seat 4, and the rotation of the centrifugal shaft 12 relative to the centrifugal seat 4 is limited by embedding the first limiting pin 13 into the groove on the centrifugal shaft 12. However, the first limiting pin 13 is not necessary. For example, the rotation of the centrifugal shaft 12 relative to the centrifugal seat 4 can be limited by the non-circular cross-section of the centrifugal shaft 12, thereby further simplifying the manufacturing of the centrifugal seat 4.

[0016] like Figure 1 As shown, each centrifuge block 10 abuts against the corresponding side surface of the adjacent centrifuge seat baffle 3 on both axial sides, so that the centrifuge block 10 slides on the corresponding side surface of the centrifuge seat baffle 3 without tilting or swaying when moving radially. Guide pins 6 are respectively installed on both sides of the centrifuge block 10, and the guide pins 6 are embedded in radial guide grooves or guide holes in the adjacent centrifuge seat baffle 3, so that the centrifuge block 10 can move radially relative to the centrifuge seat baffle 3 without rotating. Figure 3As shown, the guide pin 6 is embedded in a radial guide groove provided in the adjacent centrifuge seat baffle 3. However, when a guide hole is provided in the centrifuge seat baffle 3 instead of a guide groove, the radial outward movement distance of the centrifuge block 10 can be further limited by appropriately selecting the position of the radially outer end of the guide hole, thereby limiting the stroke of the compression spring along the radial compression of the main shaft 1, and ultimately limiting the maximum braking force of the overspeed protection safety device. Through the above measures, the centrifuge seat 4 no longer needs to accommodate and guide the centrifuge block 10, but only needs to accommodate and guide the centrifuge shaft 12, and the accommodation and guidance of the centrifuge block 10 is undertaken by the centrifuge seat baffle 3. Therefore, compared with the prior art, the radially outer dimension of the centrifuge seat 4 can be designed to be smaller, and it is no longer necessary to process a structure in the centrifuge seat 4 to accommodate and guide the centrifuge block 10. Therefore, the manufacturing of the centrifuge seat 4 is further simplified and the cost of the centrifuge seat 4 is further reduced.

[0017] like Figure 1 As shown, the overspeed protection safety device has a microswitch trigger structure at the second end of the main shaft 1. The microswitch trigger structure includes the main shaft 1, a centrifugal seat baffle 3, a second retaining ring 18, a microswitch trigger spring 19, a first microswitch trigger pin 20, a second limiting pin 21, and a second microswitch trigger pin 22. The first microswitch trigger pin 20 is at least partially inserted axially into an axial hole in the end face of the second end of the main shaft 1, and the second microswitch trigger pin 22 is partially inserted radially into a radial hole in the side face of the second end of the main shaft 1. The axial hole and the radial hole of the main shaft 1 intersect at their inner ends, thereby allowing the first microswitch trigger pin 20 and the second microswitch trigger pin 22 to interact with each other. This allows the radial inward movement of the second microswitch trigger pin 22 to cause the axial outward movement of the first microswitch trigger pin 20, and the radial inward movement of the first microswitch trigger pin 20 to cause the radial outward movement of the second microswitch trigger pin 22. The second retaining ring 18 restricts the axial outward movement of the first microswitch trigger pin 20 via the microswitch trigger spring 19, and the second limiting pin 21 prevents the second microswitch trigger pin 22 from dislodging. Under the action of the microswitch trigger spring 19, the inclined surface at the end of the first microswitch trigger pin 20 pushes against the inclined surface at the end of the second microswitch trigger pin 22, causing one end of the second microswitch trigger pin 22 to extend out and fall into the guide groove in the inner hole of the centrifugal seat baffle 3. Figure 3As shown. The inner contour of the guide groove causes the second micro switch trigger pin 22 to move radially inward from its initial position when the centrifugal seat baffle 3 rotates relative to the main shaft 1, pressed against the inner contour of the guide groove. This causes the first micro switch trigger pin 20 to move axially outward against the spring force of the micro switch trigger spring 19 and trigger the micro switch 16.

[0018] The overspeed protection safety device operates on the following principle: the rack of the construction hoist meshes with the gear 25 on the main shaft 1 of the overspeed protection safety device. As the construction hoist moves normally up and down along the guide rail, the rack fixedly installed on the guide rail drives the main shaft 1 to rotate. The centrifugal seat 4 installed on the main shaft 1 and the centrifugal shaft 12 passing through the centrifugal seat 4 and settling in the groove of the main shaft 1 rotate synchronously with the main shaft 1. When the hoist is running at normal speed, under the clamping restriction of the speed-limiting spring 8, the centrifugal shaft 12 and the centrifugal seat 4 rotate synchronously, and the safety device does not generate braking torque.

[0019] The overspeed protection safety device operates on the following principle: When the construction hoist descends at excessive speed, the centrifugal force generated by the centrifugal shaft 12 gradually increases, overcoming the clamping force limitation of the speed-limiting spring 8. When the overspeed value of the hoist descends exceeds a certain threshold, the centrifugal shaft 12 completely overcomes the clamping force of the speed-limiting spring 8 and is thrown out of the groove of the main shaft 1. When all the centrifugal shafts 12 are thrown out of the groove of the main shaft 1, the centrifugal shaft 12 and the centrifugal seat 4 can rotate relative to the main shaft 1. Due to the friction plate 9 of the centrifugal block 10 installed on the upper part of the centrifugal shaft 12 contacting the brake drum 11 and generating a torque that resists its rotation, the centrifugal shaft 12 and the centrifugal seat 4 will rotate relative to the main shaft 1. The centrifugal shaft 12 will then follow the centrifugal seat 4 to rotate to a position farther away from the groove of the main shaft 1, and the centrifugal shaft 12 will gradually slide to a position with a larger diameter of the main shaft 1. Here, the outer surface of the main shaft 1 has a cam curve, wherein the diameter of the cam curve gradually increases as it moves away from the groove of the main shaft 1 along the circumferential direction. The centrifugal block 10, which is fitted onto the upper end of the centrifugal shaft 12, is pushed up by the outer surface of the cam curve of the main shaft 1, thereby increasing the positive pressure of the centrifugal block 10 on the brake drum 11. The brake drum 11 is a fixed part, so the friction plate 9, which is bonded to the upper surface of the centrifugal block 10, generates braking torque through rotational friction with the brake drum 11. As the braking distance increases, the relative angle between the main shaft 1 and the centrifugal shaft 12 continues to increase, and the centrifugal shaft 12 moves to a position with a larger diameter than the main shaft 1. At this point, the centrifugal block 10 is already tightly pressed against the inner cavity of the brake drum 11 and cannot extend outward any further. However, the centrifugal shaft 12 continues to move to a position with a larger diameter than the cam curve of the main shaft 1, and the centrifugal shaft 12 begins to compress the disc spring 7, providing a greater positive pressure to the centrifugal block 10, thereby gradually increasing the braking torque. When the rotation angle of the main shaft 1 relative to the centrifugal seat 4 reaches its maximum value, the braking force also reaches its maximum value. Due to the structural restriction relationship between the centrifugal seat baffle 3 and the main shaft 1, the centrifugal seat 4 and the main shaft 1 no longer rotate relative to each other, and they rotate synchronously until the braking force stops the lifting mechanism. Here, the inner contour of the inner hole of the centrifugal seat baffle 3 and the outer contour of the shoulder of the main shaft 1 have a rotation restriction structure that matches each other. The rotation restriction structure limits the maximum value of the rotation angle of the centrifugal seat baffle 3 together with the centrifugal seat 4 relative to the main shaft 1 from the initial state of the overspeed protection safety device when it is not braked. Figure 3 An exemplary rotation-limiting structure is shown. For example... Figure 3As shown, the centrifugal seat baffle 3 has a roughly triangular inner hole, and the three corners of the triangular inner hole are rounded. Simultaneously, the shoulder of the main shaft 1 also has a roughly triangular outer contour, and the three corners of the outer contour of this triangle are similarly rounded. However, it can be clearly seen that the arc length of the rounded corners of the shoulder is significantly shorter than the arc length of the rounded corners of the inner hole of the centrifugal seat baffle 3. Therefore, the centrifugal seat baffle 3 can rotate relative to the main shaft 1 by a predetermined angle. This predetermined angle limits the maximum angle at which the centrifugal seat baffle 3, together with the centrifugal seat 4, can rotate relative to the main shaft 1 from the initial unbraked state of the overspeed protection safety device. Alternatively, interacting blocks can be provided on the inner hole of the centrifugal seat baffle 3 and the shoulder of the main shaft 1, such that when the centrifugal seat baffle 3 together with the centrifugal seat 4 reaches its maximum rotation angle relative to the main shaft 1 from the initial unbraked state of the overspeed protection safety device, the blocks abut against each other, thereby preventing the centrifugal seat baffle 3 together with the centrifugal seat 4 from rotating further relative to the main shaft 1. Of course, the rotation limiting structure is not limited to the above embodiment, but any other structure known in the prior art can be used.

[0020] Figure 4 The overspeed protection safety device is shown in the braking state. From Figure 4 As can be seen, the protrusion on the end face of the radial inner end of the centrifugal shaft 12 has been thrown out from the corresponding groove on the outer surface of the main shaft 1 and slid onto the cam curve of the main shaft 1. Due to the pressure of the cam curve on the centrifugal shaft 12, the disc spring 7 is in the maximum compression state, thereby the centrifugal block 10 presses against the brake drum 11 with the maximum positive pressure.

[0021] During braking, due to the relative rotation between the centrifugal seat 4 and the main shaft 1, the protruding end of the second microswitch trigger pin 22, installed in the radial hole at the tail end of the main shaft 1, contacts the inner contour of the guide groove in the inner hole of the centrifugal seat baffle 3, and is pressed into the shaft to contact the first microswitch trigger pin 20. The radial inward displacement of the second microswitch trigger pin 22 is transmitted through the contact end movement and converted into the axial outward displacement of the first microswitch trigger pin 20. The first microswitch trigger pin 20 displaces to the left, overcomes the pressure of the microswitch trigger spring 19, and extends out of the end face of the main shaft 1, contacting the trigger terminal of the microswitch 16. The microswitch 16 is triggered and cuts off the power supply to the elevator's downward control circuit.

[0022] The overspeed protection safety device reset principle is as follows: When the elevator malfunction is resolved, the elevator is operated to move upwards, causing the main shaft 1 of the overspeed protection safety device to rotate in the opposite direction. Since the frictional force between the outer surface of the main shaft 1 and the centrifugal shaft 12 is less than the frictional force between the centrifugal block 10 and the brake drum 11, the main shaft 1 rotates in the opposite direction relative to the centrifugal shaft 12 and the centrifugal seat 4. The centrifugal shaft 12 moves from the larger diameter of the cam curve of the main shaft 1 to the smaller diameter until the centrifugal shaft 12 falls back into the groove on the outer surface of the main shaft 1. At this time, the braking force is completely released, and the overspeed protection safety device automatically returns to its initial state.

[0023] As the elevator moves upward, causing the centrifugal shaft 12 to return to the groove of the main shaft 1, the second micro switch trigger pin 22 returns to its initial position in the guide groove within the inner hole of the centrifugal seat baffle 3. Specifically, under the spring pressure of the micro switch trigger spring 19, the first micro switch trigger pin 20 pushes out the second micro switch trigger pin 22 and restores it to its initial position in the guide groove. The trigger state of the micro switch 16 is released, and the power supply to the elevator downward control circuit is restored.

[0024] The above description is merely a preferred embodiment of this application. The scope of protection of this application is not limited to the above embodiments. All technical solutions falling within the concept of this application are within the scope of protection of this application. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of this application should also be considered within the scope of protection of this application.

Claims

1. An overspeed protection safety device, the overspeed protection safety device comprising: A main shaft (1) capable of rotatable support; as well as The braking device includes a centrifugal seat (4) fitted onto the outer surface of the main shaft (1) and a speed-limiting spring (8). The centrifugal seat (4) has at least two radially distributed side holes along the circumferential direction. A brake block is radially movable into each side hole, and the speed-limiting spring (8) applies a radial clamping force to the brake block. Thus, in the initial unbraked state of the overspeed protection safety device, the radially inner end of the brake block is embedded in a corresponding groove on the outer surface of the main shaft (1), thereby enabling the brake block and the centrifugal seat (4) to rotate synchronously with the main shaft (1). Its features are, The braking device includes two centrifugal seat baffles (3), the centrifugal seat baffles (3) having their inner holes respectively fitted onto the shoulders of the main shaft (1) located on both sides of the centrifugal seat (4) and fixedly connected to the centrifugal seat (4), thereby preventing the centrifugal seat (4) from moving axially on the main shaft (1). The braking block includes a centrifugal shaft (12) located radially inward, a compression spring and a centrifugal block (10) sequentially fitted onto a section of the centrifugal shaft (12) extending radially outward from the side hole of the centrifugal seat (4). The radially inner end of the centrifugal shaft (12) forms the radially inner end of the braking block, and the radially outer end of the centrifugal block (10) forms the radially outer end of the braking block. During braking, the compression spring can be compressed by the centrifugal shaft (12), thereby providing a gradually increasing positive pressure to the centrifugal block (10). Each centrifugal block (10) is attached to the corresponding side surface of the adjacent centrifugal seat baffle (3) on both sides of the axial direction, so that the centrifugal block (10) slides on the corresponding side surface of the centrifugal seat baffle (3) without tilting or swaying when it moves radially.

2. The overspeed protection safety device according to claim 1, characterized in that, Each centrifugal block (10) is equipped with guide pins (6) on both axial sides. The guide pins (6) are embedded in radial guide grooves or guide holes in adjacent centrifugal seat baffles (3), so that the centrifugal block (10) can move radially relative to the centrifugal seat baffles (3) without rotating.

3. The overspeed protection safety device according to claim 1, characterized in that, The outer surface of the main shaft (1) has a cam curve, wherein the diameter of the cam curve gradually increases as it moves away from the groove of the main shaft (1) in the circumferential direction.

4. The overspeed protection safety device according to claim 3, characterized in that, When the rotational speed of the main shaft (1) exceeds the predetermined speed threshold, the brake block, under the action of centrifugal force, overcomes the clamping force of the speed limiting spring (8) and is thrown out from the groove of the main shaft (1). The friction plate (9) set at the radial outer end of the brake block contacts and rubs with the brake drum (11) fixedly installed around the centrifugal seat (4) to generate braking torque. Under the action of the braking torque, the radial inner end of the brake block can move from the groove of the main shaft (1) to the cam curve and the centrifugal seat (4) can rotate relative to the main shaft (1) along with the brake block until the angle of rotation of the centrifugal seat (4) relative to the main shaft (1) reaches the maximum value, so that the centrifugal seat (4) and the main shaft (1) rotate synchronously until they stop.

5. The overspeed protection safety device according to claim 4, characterized in that, After braking is completed, the radial inner end of the brake block falls back into the groove of the main shaft (1) along the cam curve by reversing the main shaft (1), thereby realizing the automatic reset of the overspeed protection safety device.

6. The overspeed protection safety device according to claim 1, characterized in that, Each of the brake blocks is equipped with an independent speed-limiting spring (8).

7. The overspeed protection safety device according to claim 1, characterized in that, A unique speed limiting spring (8) is provided, which is installed in a full circle on the radial outer surface of the brake block.

8. The overspeed protection safety device according to claim 1, characterized in that, The compression spring is a disc spring (7).

9. An overspeed protection safety device, the overspeed protection safety device comprising: A rotatably supported spindle (1), the spindle (1) having a first end for mounting a gear (25) and a second end away from the gear (25); and The braking device includes a centrifugal seat (4) fitted onto the outer surface of the main shaft (1) and a speed-limiting spring (8). The centrifugal seat (4) has at least two radially distributed side holes along the circumferential direction. A brake block is radially movable into each side hole, and the speed-limiting spring (8) applies a radial clamping force to the brake block. Thus, in the initial unbraked state of the overspeed protection safety device, the radially inner end of the brake block is embedded in a corresponding groove on the outer surface of the main shaft (1), thereby enabling the brake block and the centrifugal seat (4) to rotate synchronously with the main shaft (1). Its features are, The braking device includes two centrifugal seat baffles (3), the centrifugal seat baffles (3) having their inner holes respectively fitted onto the shoulders of the main shaft (1) located on both sides of the centrifugal seat (4) and fixedly connected to the centrifugal seat (4), thereby preventing the centrifugal seat (4) from moving axially on the main shaft (1). A microswitch triggering structure is provided at the second end of the main spindle (1). The microswitch triggering structure includes a first microswitch trigger pin (20) and a second microswitch trigger pin (22). The first microswitch trigger pin (20) is inserted axially at least partially into an axial hole in the end face of the second end of the main spindle (1), and the second microswitch trigger pin (22) is inserted radially into a radial hole in the side face of the second end of the main spindle (1). The axial hole and the radial hole intersect at their inner ends, thereby the first microswitch trigger pin (20) and the second microswitch trigger pin (22) interact with each other, such that the radial inward movement of the second microswitch trigger pin (22) can cause the axial outward movement of the first microswitch trigger pin (20), and the axial inward movement of the first microswitch trigger pin (20) can cause the radial outward movement of the second microswitch trigger pin (22). Wherein, the end of the second micro switch trigger pin (22) extending from the main shaft (1) is placed in a guide groove in the inner hole of the centrifugal seat baffle (3) located near the second end of the main shaft (1). The inner contour of the guide groove is such that when the centrifugal seat baffle (3) rotates relative to the main shaft (1), the second micro switch trigger pin (22) is pressed by the inner contour of the guide groove and moves radially inward from its initial position, thereby causing the first micro switch trigger pin (20) to move axially outward and trigger the micro switch (16).

10. The overspeed protection safety device according to claim 9, characterized in that, The micro switch triggering structure includes a micro switch triggering spring (19), which axially presses the first micro switch triggering pin (20) inward. After braking is completed, by reversing the main shaft (1), the first micro switch triggering pin (20) can move axially inward under the action of the micro switch triggering spring (19), and the second micro switch triggering pin (22) moves radially outward to the initial position under the action of the first micro switch triggering pin (20), thereby releasing the triggering state of the micro switch (16).

11. The overspeed protection safety device according to claim 9, characterized in that, The microswitch triggering structure includes a second limiting pin (21) to prevent the second microswitch triggering pin (22) from dislodging from the radial hole of the spindle (1).

12. The overspeed protection safety device according to claim 9, characterized in that, The outer surface of the main shaft (1) has a cam curve, wherein the diameter of the cam curve gradually increases as it moves away from the groove of the main shaft (1) in the circumferential direction.

13. The overspeed protection safety device according to claim 12, characterized in that, When the rotational speed of the main shaft (1) exceeds the predetermined speed threshold, the brake block, under the action of centrifugal force, overcomes the clamping force of the speed limiting spring (8) and is thrown out from the groove of the main shaft (1). The friction plate (9) set at the radial outer end of the brake block contacts and rubs with the brake drum (11) fixedly installed around the centrifugal seat (4) to generate braking torque. Under the action of the braking torque, the radial inner end of the brake block can move from the groove of the main shaft (1) to the cam curve and the centrifugal seat (4) can rotate relative to the main shaft (1) along with the brake block until the angle of rotation of the centrifugal seat (4) relative to the main shaft (1) reaches the maximum value, so that the centrifugal seat (4) and the main shaft (1) rotate synchronously until they stop.

14. The overspeed protection safety device according to claim 13, characterized in that, After braking is completed, the radial inner end of the brake block falls back into the groove of the main shaft (1) along the cam curve by reversing the main shaft (1), thereby realizing the automatic reset of the overspeed protection safety device.

15. The overspeed protection safety device according to claim 9, characterized in that, Each of the brake blocks is equipped with an independent speed-limiting spring (8).

16. The overspeed protection safety device according to claim 9, characterized in that, A unique speed limiting spring (8) is provided, which is installed in a full circle on the radial outer surface of the brake block.

17. A construction hoist, characterized in that, The construction hoist has an overspeed protection safety device according to any one of claims 1 to 16, wherein a gear (25) is installed at the first end of the main shaft (1) of the overspeed protection safety device, and the gear (25) meshes with a rack fixedly installed on the guide rail frame of the construction hoist.

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