Emergency braking structure for chain saw

Abstract

The utility model relates to an emergency braking structure for a chain saw, which comprises a gear box, the front end of the gear box is rotatably connected with a driving shaft, a follow-up shaft is nested in the driving shaft, a transmission torsion spring is sleeved on the outer sides of the follow-up shaft and the driving shaft, and the upper side of one axial end of the transmission torsion spring extends to form an extension part. The upper side of the transmission torsion spring is provided with a follow-up rod with the vertical layer projection of an arc-shaped structure, and the lower end of the follow-up rod is provided with a braking protrusion abutting against the extension part. Meanwhile, the lower end of one end of the follow-up rod is provided with a driving rod which is rotationally connected with the gearbox, the vertical layer projection of the driving rod is of a U-shaped structure, and the follow-up rod can be driven to rotate anticlockwise by rotating the driving rod. Therefore, the stop lever is arranged on one side of the driving rod, when the driving rod rotates upwards to force the pressing plate to move downwards, the stop lever abuts against the lower end face of the driving rod, the brake state can be kept through the stop lever, and misoperation caused by tension of a user in an emergency state is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of chain saw brake mechanisms, in particular to an emergency brake structure for a chain saw. Background Art

[0002] The chain saw is a traditional electric tool. In actual operation, it is dangerous. When the danger occurs, the chain saw must be braked urgently to stop the chain in a very short time to prevent the chain from cutting the operator.

[0003] The existing chain saw power structure realizes the torsional force transmission between the output shaft and the transmission shaft through a transmission torsion spring. The brake structure adopted generally includes an extension portion arranged at one axial end of the transmission torsion spring. By utilizing the characteristics of the transmission torsion spring itself, the distance between the extension portion and the side end face of the output shaft is changed through a corresponding pressure plate, thereby changing the diameter of the transmission torsion spring itself, so that the transmission torsion spring is separated from the output shaft, thereby realizing the cutting off of power transmission and achieving the braking process.

[0004] The structure of the prior art device is generally simple, and generally only includes a pressure plate and a push rod connected to the pressure plate. When the user pushes the push rod, the pressure plate is pressed down to realize the braking process. The prior art device generally lacks a corresponding anti-return structure, that is, when the user cancels the thrust applied to the pressure plate, the elastic potential energy accumulated in the transmission torsion spring is released, and the distance between the extension part and the side end face of the output shaft increases, and at this time, the push rod automatically resets.

[0005] In actual use, when an unexpected situation occurs and emergency braking is required, if the operator cancels the thrust on the push rod before the dangerous situation is eliminated, the chain saw is likely to restart. Therefore, we believe that a chain saw emergency brake structure with a non-return structure is needed, which allows the operator to have sufficient reaction time to eliminate the dangerous source. Summary of the invention

[0006] In view of the deficiencies in the prior art, the utility model proposes an emergency brake structure for a chain saw, which has the advantage of avoiding misoperation through a non-return structure, and solves the disadvantage that operators of the prior art devices are very likely to misoperate due to the on-site environment, thereby causing danger.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] The emergency brake structure for a chain saw comprises a gear box, wherein the front end of the gear box is rotatably connected to a driving shaft, a follower shaft is nested inside the driving shaft, a transmission torsion spring is commonly sleeved on the outer sides of the driving shaft and the follower shaft, the inner wall of the transmission torsion spring abuts against the driving shaft and the follower shaft, and an extension portion is extended on the upper side of one axial end of the transmission torsion spring, a follower rod with a vertical plane projection of an arc structure is arranged on the upper side of the transmission torsion spring, a braking protrusion is arranged at the lower end of the follower rod, and the lower end surface of the braking protrusion abuts against the extension portion, the upper end of the follower rod is rotatably connected to the gear box through a rotating shaft, a driving rod with a vertical plane projection of a U-shaped structure is arranged on the lower side of one end of the follower rod, the follower rod is embedded in the U-shaped opening of the driving rod, and a stop rod is arranged on one side of the driving rod, and when the driving rod rotates upward to force the braking protrusion to move downward, the stop rod abuts against the lower end surface of the driving rod.

[0009] Preferably, the projection of the baffle on the vertical plane is an L-shaped structure, a slide rail is sleeved on the outer side of the horizontal section of the baffle, the slide rail is fixedly connected to the gear box, the baffle is rotatably connected to a driven rod at one end away from the driving rod, and the upper end of the driven rod is slidably connected to the gear box.

[0010] Preferably, the upper end of the driven rod is rotatably connected to a pressure plate whose vertical plane projection is an inverted L-shaped structure, and the upper end surface of the pressure plate abuts against the follower rod. The pressure plate is provided with through grooves running through the left and right sides, and a limiting rod is inserted in the through groove. The limiting rod is fixedly connected to the gear box, and a limiting groove is run through the limiting rod, and the pressure plate is inserted in the limiting groove to perform up and down linear motion.

[0011] Preferably, a compression spring is fixedly connected to the upper end surface of the limiting rod, and the other axial end of the compression spring abuts against the lower end surface of the horizontal section of the pressure plate.

[0012] Preferably, a mounting bracket is fixedly connected to one side of the gear box, and the mounting bracket is rotationally connected to the middle section of the driving rod through a pin shaft. When the compression spring is not affected by external force, the two vertical sections of the driving rod are respectively in contact with the follower rod and the mounting bracket.

[0013] Preferably, the upper end of the vertical section of the baffle rod is a spherical structure, and during the process of increasing the elastic potential energy accumulated by the compression spring, the vertical section of the baffle plate does not contact the lower end surface of the driving rod.

[0014] Preferably, the height of the central axis of the rotating shaft is greater than the height of the upper end surface of the braking protrusion, and when the follower rod rotates in the spiral direction of the transmission torsion spring, the braking protrusion moves downward.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] The utility model realizes the counterclockwise rotation of the follower rod by rotating the driving rod in linkage, so that the braking protrusion can move downward to force the extension part to move downward, expand the diameter of the transmission torsion spring to realize the separation of the driven torsion spring from the follower shaft and the driving shaft. At the same time, by arranging a blocking rod at the lower side of the driving rod and constraining the blocking rod to be slidably connected with the gear box, the blocking rod can be moved to the right during the upward movement of the driving rod to prevent the downward reset and realize the maintenance of the braking state, thereby avoiding the user's misoperation due to nervousness in an emergency state. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0018] Figure 2 This is a schematic diagram of the cooperation between the transmission torsion spring and the drive shaft of the utility model;

[0019] Figure 3 This is a front view of the utility model;

[0020] Figure 4 This is a schematic diagram of the cooperation between the driving rod and the follower rod of the utility model;

[0021] Figure 5 This is a schematic diagram of the connection between the pressing plate and the driven rod of the utility model.

[0022] In the figure: 1. gear box; 2. follower rod; 3. transmission torsion spring; 4. drive rod; 5. stop rod; 6. follower shaft; 7. drive shaft; 8. extension; 9. brake protrusion; 10. rotating shaft; 11. mounting frame; 12. slide rail; 13. driven rod; 14. limit rod; 15. compression spring; 16. pressure plate; 17. through groove; 18. limit groove; 19. pin shaft. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0025] Please refer to Figure 1-5 An emergency brake structure for a chain saw includes a gear box 1, wherein corresponding transmission gears and driving gears are arranged inside the gear box 1, wherein in practice, the transmission gears and the corresponding driving motors should be key-connected, therefore, through the meshing transmission connection between the transmission gears and the driving gears, the transmission ratio between the driving gears and the driving motors can meet the requirements.

[0026] Correspondingly, a driving shaft 7 is coaxially fixedly connected to the driving gear, and the driving shaft 7 protrudes out of the gear box 1, so that the follower shaft 6 located outside the gear box 1 can be affected by the driving shaft 7 to drive the saw blade required by the chain saw to rotate.

[0027] Specifically, the device is provided with a transmission torsion spring 3 on the outside of the driving shaft 7, and the other axial end of the transmission torsion spring 3 is provided on the outside of the follower shaft 6, which enables the device to achieve the transmission of torsional force between the driving shaft 7 and the follower shaft 6 through the transmission torsion spring 3.

[0028] At the same time, the device is provided with an extension portion 8 extending from one axial end of the transmission torsion spring 3, and the distance between the extension portion 8 and the central axis of the drive shaft 7 is greater than the distance between the transmission torsion spring 3 and the central axis of the drive shaft 7, that is, when the device is not affected by external forces, the transmission torsion spring 3 is tightly fitted with the side end surfaces of the drive shaft 7 and the follower shaft 6, while there is a gap between the extension portion 8 and the side end surfaces of the drive shaft 7 or the follower shaft 6.

[0029] For the convenience of installation, the device sets the extension part 8 and the driving shaft 7 to be in the same vertical plane, and the transmission torsion spring 3 is located outside the gear box 1 .

[0030] Therefore, the device utilizes the structural characteristics of the transmission torsion spring 3. When the distance between the extension 8 and the side end face of the drive shaft 7 is reduced, the diameter of the transmission torsion spring 3 will increase accordingly. At this time, the transmission torsion spring 3 is not tightly fitted with the drive shaft 7 and the follower shaft 6, and the transmission torsion spring 3 fails to transmit the torsional force. At this time, the reaction force applied to the follower shaft 6 during the operation of the chain can achieve the purpose of quickly stopping the follower shaft 6.

[0031] Specifically, in order to control the distance between the extension 8 and the side end surface of the drive shaft 7, the device constrains the extension 8 to be located on the upper side of the drive shaft 7, and a follower rod 2 with a vertical plane projection as an arc structure is provided on the upper side of the transmission torsion spring 3.

[0032] Therefore, by providing a braking protrusion 9 at the lower end of the follower rod 2 and constraining the lower end surface of the braking protrusion 9 to abut against the extension 8, the height of the extension 8 can be controlled by moving the braking protrusion 9 downward.

[0033] Specifically, the device constrains the upper end of the follower rod 2 to be rotatably connected to the gear box 1 via the rotating shaft 10. As shown in the figure, when the follower rod 2 rotates counterclockwise, the braking protrusion 9 moves downward. At this time, the upper and lower position relationship can be used to force the extension part 8 to move downward synchronously to reduce the gap between the side end face of the drive shaft 7.

[0034] Furthermore, as shown in the figure, since the extension portion 8 is extended from one of the axial ends of the original transmission torsion spring 3, and the spiral direction of the transmission torsion spring 3 itself is counterclockwise, the distance between the right end of the extension portion 8 and the side end face of the drive shaft 7 is greater than the distance between the left end of the extension portion 8 and the side end face of the drive shaft 7. At this time, by constraining the upper end face height of the braking protrusion 9 to be less than the height of the central axis of the rotating shaft 10, the follower rod 2 moves downward and rightward synchronously during the counterclockwise rotation process around the central axis of the rotating shaft 10, so that the braking protrusion 9 can reduce the distance between the extension portion 8 and the side end face of the drive shaft 7 more quickly, so that the transmission torsion spring 3 can separate from the drive shaft 7 and the follower shaft 6 faster.

[0035] Specifically, in order to control the position of the driving rod 4 in the initial state, that is, when the transmission torsion spring 3 can be tightly fitted to the driving shaft 7, the braking protrusion 9 and the extension 8 are in abutment state, so as to prevent the follower rod 2 from rotating clockwise so that the braking protrusion 9 and the extension 8 are not in contact, thereby preventing the braking protrusion 9 from pressing the extension 8 downward so that the transmission torsion spring 3 and the driving shaft 7 are separated for a longer time. The device constrains that one side of the gear box 1 is fixedly connected to a mounting frame 11, and the mounting frame 11 is fixedly connected to the driving rod 4 through a pin 19.

[0036] Therefore, by constraining the height of the central axis of the pin 19 to be greater than the height of the upper end surface of the horizontal section of the driving rod 4, the lower end of the driving rod 4 can force the follower rod 2 to rotate counterclockwise when it moves upward and rightward. At the same time, in the initial state of further constraint, the outer wall of the right vertical section of the driving rod 4 abuts against the mounting frame 11, so that the driving rod 4 at this time cannot rotate downward and rightward, but can only drive the follower rod 2 to rotate counterclockwise upward and rightward.

[0037] Similarly, in order to ensure that in the initial state, the driving rod 4 can directly drive the follower rod 2 to rotate counterclockwise when it rotates upward and to the right, thereby reducing the system operation time, the device constrains that in the initial state, the inner wall of the left vertical section of the driving rod 4 abuts against the inner side of the follower rod 2. At this time, the driving rod 4 can directly force the follower rod 2 to rotate counterclockwise when it rotates upward and to the right.

[0038] Similarly, in order to control the position of the driving rod 4 in the braking state, that is, when the driving rod 4 moves upward to force the follower rod 2 to rotate counterclockwise, so that the transmission torsion spring 3 is separated from the driving shaft 7, the device at this time is slidably connected with a stopper rod 5 at the lower end of the driving rod 4. The stopper rod 5 can be moved below the driving rod 4 through the sliding connection to force the position of the driving rod 4, forcing the driving rod 4 to not move downward at this time, that is, the braking protrusion 9 always maintains the state of applying downward pressure to the extension 8.

[0039] The device constrains the L-shaped structure of the vertical projection of the blocking rod 5. This is achieved by sleeve-arranging a slide rail 12 outside the horizontal section of the baffle plate, and the constraining slide rail 12 is fixedly connected to the gear box 1 to realize the sliding connection between the blocking rod 5 and the gear box 1, so that the blocking rod 5 can make a left and right linear movement relative to the gear box 1. At the same time, the vertical section of the baffle plate itself can play a good supporting effect on the driving rod 4, ensuring that it cannot move downward.

[0040] Specifically, in order to increase the reliability and stability of the device, a pressure plate 16 is provided on the lower side of the end of the follower rod 2 away from the driving rod 4. A through groove 17 is opened on the left and right sides of the pressure plate 16. A limit rod 14 is inserted into the through groove 17, which constrains the limit rod 14 to be fixedly connected to the gear box 1, so that the pressure plate 16 can only make a straight line movement up and down relative to the gear box 1.

[0041] At the same time, the vertical plane projection of the pressure plate 16 is an inverted L-shaped structure. The lower end of the vertical section of the pressure plate 16 is rotatably connected to the driven rod 13, and the other end of the driven rod 13 is rotatably connected to the horizontal section of the baffle rod 5. Therefore, when the pressure plate 16 moves linearly downward, the driven rod 13 can be used to push the baffle rod 5 to move to the right.

[0042] Therefore, in practice, when the driving rod 4 rotates upward to force the follower rod 2 to rotate counterclockwise, the end of the follower rod 2 away from the driving rod 4 drives the pressure plate 16 to move linearly downward, and the stop rod 5 is used to constrain the position of the driving rod 4.

[0043] Furthermore, the device has a limiting groove 18 extending through the limiting rod 14 , and the pressing plate 16 is inserted into the limiting groove 18 , which can ensure that the pressing plate 16 cannot move forward or backward.

[0044] It should be noted that, in the actual braking process, since the mounting bracket 11 is located on the right side of the driving rod 4, in practice, during the upward rotation of the driving rod 4, the left side of the driving rod 4, that is, the side of the driving rod 4 close to the follower rod 2, moves upward a distance greater than the upward movement distance of the right side of the driving rod 4, and the stop rod 5 is located on the left side of the driving rod 4, which can make left and right linear motion relative to the gear box 1. Therefore, during the upward rotation of the driving rod 4, the stop rod 5 can move to the left until it abuts against the lower end surface of the driving rod 4, thereby realizing the position constraint of the driving rod 4.

[0045] Therefore, by adjusting the position of the blocking rod 5 in the initial state, it can be achieved that during the upward rotation of the driving rod 4, the blocking rod 5 never contacts the lower end surface of the driving rod 4, and when the blocking rod 5 moves rightward to be in the same vertical plane as the driving rod 4 and the blocking rod 5 abuts against the lower end surface of the driving rod 4, the transmission torsion spring 3 separates from the side end surface of the driving shaft 7 to achieve a braking effect. This can reduce the resistance encountered by the user during the upward rotation of the driving rod 4, and ensure the rapidity of the braking process.

[0046] Furthermore, the upper end of the vertical section of the restraining rod 5 of the device is a spherical structure. This can ensure that the contact area between the restraining rod 5 and the driving rod 4 is at the minimum during the abutment between the driving rod 4 and the restraining rod 5, that is, maintain the minimum friction resistance. At this time, the restraining rod 5 provides vertical support for the driving rod 4 to prevent the driving rod 4 from moving downward, and there is also an angle between the lower end surface of the driving rod 4 and the horizontal plane at this time. Therefore, at this time, the user can also rotate the driving rod 4 counterclockwise to force the restraining rod 5 to move to the left to achieve the resetting of the driving rod 4.

[0047] It should be emphasized that in practice, due to the difference between dynamic friction and static friction resistance, when the drive rod 4 rotates counterclockwise to reset, the user will inevitably encounter greater friction resistance in the early stage. This can ensure that the drive rod 4 will not rotate counterclockwise to reset by itself due to accidental touch under unnecessary circumstances.

[0048] Furthermore, since the length of the driven rod 13 itself remains unchanged, the driven rod 13 is used to adjust the position of the blocking rod 5 by changing its own inclination angle. Therefore, in practice, the driven rod 13 needs to be subjected to longitudinal and vertical forces at the same time during the change of the inclination angle. Therefore, in order to further reduce the resistance encountered by the user in the process of pushing the blocking rod 5 to the left, the device is fixedly connected with a compression spring 15 on the upper end face of the limit rod 14, and the other axial end of the compression spring 15 is fixedly connected to the lower end face of the horizontal section of the pressure plate 16. In this way, the compression spring 15 is used to provide an upward thrust for the driven rod 13, and the leftward thrust provided by the driving rod 4 to the blocking rod 5 can be cooperated with, so that the resetting process of the driving rod 4 can be completed relatively easily.

[0049] It should be emphasized that, as shown in the figure, the upper end of the driving rod 4 is provided with a corresponding handle groove, and the height of the upper end of the driving rod 4 is greater than the height of the gear box 1. Therefore, in actual use, the user can hold the driving rod 4 in real time to help stabilize the chain saw and control the internal transmission of the chain saw, that is, the user holds the chain saw housing at the upper end of the gear box 1 with one hand and holds the driving rod 4 with the other hand. At this time, when an accident occurs, the user can quickly push the driving rod 4 to rotate clockwise to complete the emergency braking process, which is in line with the state of the user's hands in an emergency state. Or, in practice, although the user does not hold the driving rod 4, considering the size of the chain saw housing, when the user holds the middle section of the chain saw housing, the position of the back of the user's hand must be in a state of approximate fit with the driving rod 4. At this time, if an accident occurs, the user can quickly rotate the wrist and use the back of the hand or wrist to make the driving rod 4 rotate clockwise.

[0050] In actual use, the utility model:

[0051] First, the user pulls the drive rod 4 toward the gear box 1. At this time, the drive rod 4 abuts against the mounting bracket 11, and the transmission torsion spring 3 fits tightly against the side end surfaces of the drive shaft 7 and the follower shaft 6.

[0052] Then, the user opens the same driving mechanism as the chain saw itself, and uses the gears inside the gear box 1 to drive the driving shaft 7, and then drives the follower shaft 6 to start working;

[0053] Afterwards, when an emergency occurs, the user pushes the driving rod 4 away from the gear box 1. At this time, the driving rod 4 pushes the follower rod 2 upward to rotate counterclockwise, and the braking protrusion 9 presses the extension 8 downward to separate the transmission torsion spring 3 from the follower shaft 6 and the driving shaft 7.

[0054] Finally, when the emergency notice is canceled, the user pulls the drive rod 4 toward the gear box 1. At this time, the compression spring 15 releases the stored elastic potential energy, and the drive rod 4 provides a leftward pushing force for the blocking rod 5. The pressure plate 16 moves up and the blocking rod 5 moves left. At this time, the drive rod 4 is reset.

[0055] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An emergency brake structure for a chain saw, characterized in that: It comprises a gear box (1), the front end of the gear box (1) is rotatably connected to a drive shaft (7), and a follower shaft (6) is nested inside the drive shaft (7); The driving shaft (7) and the follower shaft (6) are both sleeved with a transmission torsion spring (3), the inner wall of the transmission torsion spring (3) is in contact with the driving shaft (7) and the follower shaft (6), and an extension portion (8) is extended from the upper side of one axial end of the transmission torsion spring (3); A follower rod (2) having an arc-shaped structure in vertical plane projection is arranged on the upper side of the transmission torsion spring (3); a brake protrusion (9) is arranged at the lower end of the follower rod (2); and the lower end surface of the brake protrusion (9) is in contact with the extension portion (8); The upper end of the follower rod (2) is rotatably connected to the gear box (1) via a rotating shaft (10); a driving rod (4) having a U-shaped structure in vertical plane projection is arranged on the lower side of one end of the follower rod (2); the follower rod (2) is embedded in the U-shaped opening of the driving rod (4); A blocking rod (5) is arranged on one side of the driving rod (4); when the driving rod (4) rotates upward to force the braking protrusion (9) to move downward, the blocking rod (5) abuts against the lower end surface of the driving rod (4).

2. The emergency brake structure for a chain saw according to claim 1, characterized in that: The projection of the baffle rod (5) on the vertical plane is an L-shaped structure, and a slide rail (12) is sleeved on the outer side of the horizontal section of the baffle, and the slide rail (12) is fixedly connected to the gear box (1); The end of the baffle away from the driving rod (4) is rotatably connected to a driven rod (13), and the upper end of the driven rod (13) is slidably connected to the gear box (1).

3. The emergency brake structure for a chain saw according to claim 2, characterized in that: The upper end of the driven rod (13) is rotatably connected to a pressure plate (16) having a vertical plane projection of an inverted L-shaped structure, and the upper end surface of the pressure plate (16) abuts against the driven rod; The pressure plate (16) is provided with through grooves (17) on the left and right sides, a limiting rod (14) is inserted into the through groove (17), the limiting rod (14) is fixedly connected to the gear box (1), and a limiting groove (18) is provided on the limiting rod (14), and the pressure plate (16) is inserted into the limiting groove (18) to perform vertical linear movement.

4. The emergency brake structure for a chain saw according to claim 3, characterized in that: The upper end surface of the limiting rod (14) is fixedly connected with a compression spring (15), and the other axial end of the compression spring (15) abuts against the lower end surface of the horizontal section of the pressing plate (16).

5. The emergency brake structure for a chain saw according to claim 4, characterized in that: A mounting frame (11) is fixedly connected to one side of the gear box (1), and the mounting frame (11) is rotatably connected to the middle section of the driving rod (4) via a pin shaft (19); When the compression spring (15) is not affected by external forces, the two vertical sections of the driving rod (4) are in contact with the follower rod (2) and the mounting frame (11) respectively.

6. The emergency brake structure for a chain saw according to claim 4, characterized in that: The upper end of the vertical section of the baffle rod (5) is a spherical structure, and during the process of increasing the elastic potential energy accumulated by the compression spring (15), the vertical section of the baffle plate does not contact the lower end surface of the driving rod (4).

7. The emergency brake structure for a chain saw according to claim 1, characterized in that: The height of the central axis of the rotating shaft (10) is greater than the height of the upper end surface of the braking protrusion (9), and when the follower rod (2) rotates in the spiral direction of the transmission torsion spring (3), the braking protrusion (9) moves downward.

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