Winch for preventing reverse motion of belt rope type telescopic mast

Abstract

The present invention relates to a winch comprising: a drum around which a rope is wound; a driving shaft assembly including a driving shaft rotated by means of torque transmitted through a handle, a driving gear fixed onto the driving shaft, a handle fixing nut screw-coupled to a thread part formed on the driving shaft, and a plane washer fixedly provided at the front end of the driving shaft so as to prevent the separation of the handle fixing nut; a ratchet assembly including a ratchet wheel, which is provided between the driving gear and the handle fixing nut on the driving shaft so as to be freely rotatable, and a pawl for restraining that the ratchet wheel rotates only in one direction; and a reduction gear connected by means of a plurality of gears so that the rotation of the driving gear is decelerated and transmitted to the drum, wherein the ratchet wheel restrains the driving shaft so as to rotate only in one direction by means of the pawl when the ratchet wheel can rotate together with the driving shaft by means of frictional force generated by the tightening of the handle fixing nut, a flat part is formed between the front end of the driving shaft and the thread part, and, when the handle fixing nut rotates in the counterclockwise direction and moves from the thread part to the flat part, the handle fixing nut becomes capable of free rotation.

Description

A winch that prevents reverse movement of a belt-rope telescopic mast.

[0001] The present invention relates to a winch having a reduction mechanism capable of raising or lowering a heavy load by rotating a handle forward or backward on a belt rope type telescopic mast.

[0002] A winch is a machine that lifts or lowers heavy objects by wrapping wire or rope around a cylindrical drum. These winches are used in a variety of industries, including civil engineering, manufacturing, shipbuilding, and mining. They are also used in telescopic masts, which carry video equipment like cameras or communication devices like antennas, and raise them to a certain height from the ground.

[0003] A telescopic mast is a device used to expand the observation range of imaging equipment or to improve the communication performance of communication equipment by lifting imaging or communication equipment mounted on the top to a certain height from the ground. It is composed of a configuration in which a number of cylindrical joints of different diameters are connected in an interlocking manner through a plurality of belt ropes and are capable of being extended.

[0004] Among the multiple belt ropes that make up a telescopic mast, the lowest belt rope is connected to a winch, and when the winch drum rotates forward or backward according to the rotation operation of the winch, the lowest belt rope is wound around the drum or the belt rope that was wound around the drum is released, and the multiple joints are simultaneously raised or lowered by a unique mechanical mechanism, enabling the loaded equipment to be raised or lowered.

[0005] A conventional winch applied to a telescopic mast basically includes a handle into which an external force is input to wind or unwind a belt rope. It also includes a main shaft that rotates in response to the external force input through the handle, a drum that rotates in conjunction with the rotation of the main shaft and around which the belt rope is wound, a ratchet to prevent reverse rotation of the drum, and a plurality of gears installed between the main shaft and the drum.

[0006] In this conventional winch, when the handle is turned in the upward direction (clockwise), the main shaft coupled to the handle rotates, and the rotation of the main shaft is reduced by the gears configured between the main shaft and the drum and transmitted to the drum, thereby rotating the drum and winding the belt rope. Then, when the rotation of the handle is stopped, the drum's rotation in the opposite direction is prevented by the ratchet, preventing the belt rope from being released.

[0007] These conventional winches have many advantages in terms of operator operability, but it has been discovered that abnormal operations that were not anticipated during the design, especially abnormal operations such as raising the telescopic mast by turning the handle in the lowering direction (counterclockwise), can cause damage to the winch due to overload, or cause a safety problem in that the telescopic mast can rapidly lower itself when the handle operation is stopped during the rise because the ratchet is deactivated.

[0008] Therefore, in order to operate the winch more stably, we developed a winch that can be used safely even in abnormal operation by the operator.

[0009] The purpose of the present invention is to provide a safe winch that can fundamentally prevent problems such as damage to the gear structure of the winch or dropping of the weight being raised, even if an operator attempts an abnormal operation to raise a weight by turning the handle counterclockwise in the initial state of operation where no load is applied to the drum.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011] The present invention relates to a winch, and in one embodiment, the winch comprises a drum on which a rope is wound, a drive shaft that rotates by a torque transmitted through a handle, a drive gear fixed on the drive shaft, a handle fixing nut screwed into a threaded portion formed on the drive shaft, and a flat washer fixedly installed to a front end of the drive shaft to prevent the handle fixing nut from coming off, a ratchet wheel installed on the drive shaft so as to be freely rotatable between the drive gear and the handle fixing nut, and a pawl that restrains the ratchet wheel to rotate in only one direction, and a reduction gear including a plurality of gears connected so that the rotation of the drive gear is transmitted at a reduced speed to the drum, wherein the ratchet wheel restrains the drive shaft to rotate in only one direction by the pawl when the ratchet wheel can rotate together with the drive shaft by a frictional force caused by tightening of the handle fixing nut, and a smooth portion is formed between the front end of the drive shaft and the threaded portion, and the handle fixing nut rotates counterclockwise. When the handle fixing nut is rotated and moved from the screw portion to the smooth portion, it is in a state where it can rotate freely.

[0012] In one embodiment of the present invention, the smooth portion may have a diameter corresponding to the diameter of the screw portion, and a length corresponding to the height of the handle fixing nut.

[0013] In addition, it may be desirable to design the frictional force acting on the handle fixing nut and screw thread to be less than the load acting on the drive shaft through the drum.

[0014] In addition, the drive shaft assembly may further include a compression spring disposed between the handle fixing nut and the flat washer on the drive shaft.

[0015] The above compression spring exerts an elastic force to press the handle fixing nut toward the threaded portion when the handle fixing nut is in a state where it can freely rotate on the smooth portion.

[0016] In addition, the compression spring causes the handle fixing nut to come into close contact with the beginning of the threaded portion, and thus, screw fastening to the threaded portion can be initiated as soon as the handle fixing nut rotates clockwise.

[0017] The winch of the present invention having the above configuration is configured so that when the handle is continuously rotated counterclockwise, the handle fixing nut that transmitted torque to the drive shaft is detached from the threaded portion and converted to a state where it can rotate freely by using the smooth portion formed at the tip of the drive shaft. Accordingly, if the operator attempts to raise a heavy load by rotating the handle counterclockwise contrary to the manual due to a reason such as an error or mistake, the winch operation is deactivated, thereby preventing damage to the winch and safety accidents in advance.

[0018] In addition, by further including a compression spring positioned between the handle fixing nut and the flat washer on the drive shaft, the handle fixing nut can be induced to automatically begin to engage the threaded portion as soon as normal operation of rotating the handle clockwise is attempted. Accordingly, the winch of the present invention allows the operator to conveniently use the winch even though a smooth portion that disables winch operation is formed at the front end of the drive shaft.

[0019] However, the technical effects that can be obtained through the present invention are not limited to the above-described effects, and other effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0020] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0021] Figure 1 is a perspective view of a winch according to the present invention.

[0022] Fig. 2 is a perspective view showing the winch of Fig. 1 in an exploded state.

[0023] Figure 3 is a right side view showing the combined structure of the drum, drive shaft assembly, ratchet assembly, and reduction gear.

[0024] Figure 4 is a front view corresponding to Figure 3.

[0025] Figure 5 is a drawing showing a state in which a weight is raised by rotating the handle clockwise.

[0026] Figure 6 is a drawing showing a state in which the handle is rotated counterclockwise to lower a heavy object.

[0027] Figure 7 is a drawing showing a conventional winch.

[0028] FIG. 8 is a drawing illustrating a case in which the handle is continuously turned counterclockwise in a winch according to the present invention.

[0029] Fig. 9 is a perspective view showing the joint structure of a handle fixing nut to a drive shaft in a winch according to the present invention.

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention, they should be construed as meanings and concepts consistent with the technical spirit of the present invention.

[0031] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0032] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0033] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0034] Fig. 1 is a perspective view of a winch (10) according to the present invention, and Fig. 2 is an exploded perspective view of the winch (10) of Fig. 1. The winch (10) can be broadly divided into a drum (100), a drive shaft assembly (200), a ratchet assembly (400), and a reduction gear (500) that form a drive system. In addition, a frame (600) that forms a structure supporting the drive system and a handle (300) for an operator to operate the winch (10) are included. In order to understand the winch (10) of the present invention, a description of the drive system is important, and therefore, the related contents will be described in detail first.

[0035] Fig. 3 is a right side view showing the combined structure of a drum (100), a drive shaft assembly (200), a ratchet assembly (400), and a reduction gear (500) omitting the configuration of a frame (600), etc., and Fig. 4 is a corresponding front view. However, in Fig. 4, the configuration of the ratchet assembly (400) is omitted, and Fig. 4 shows a state in which no load is applied to the winch (10).

[0036] Referring to FIGS. 1 to 4, the drum (100) corresponds to a cylindrical rotating body around which a wire or rope (not shown) on which a weight load is applied is wound. With respect to the direction shown in FIGS. 1 and 2, when the drum (100) rotates counterclockwise, the weight rises, and conversely, when it rotates clockwise, the weight descends. This description of the rotation direction is maintained throughout the following specification.

[0037] The drive shaft assembly (200) is configured as an input shaft that is rotated by a handle (300) operated by an operator and provides this rotational force to the drum (100). However, the driving force of the drive shaft assembly (200) is transmitted to the drum (100) through a reduction gear (500). The drive shaft assembly (200) includes a drive gear (220) that is connected to the reduction gear (500), and is also connected to a ratchet assembly (400) that allows one-way rotation of the drive shaft assembly (200) while restricting rotation in the opposite direction.

[0038] The drive shaft assembly (200) includes a drive shaft (210), and a drive gear (220) is fixed on the drive shaft (210). The drive shaft (210) and the drive gear (220) always rotate together. Therefore, the drive shaft (210) and the drive gear (220) may be formed integrally. The drive gear (220) of the drive shaft assembly (200) is mechanically connected to the drum (100) through the intervention of a reduction gear (500).

[0039] The reduction gear (500) includes an internal gear (510) and a driven gear (520). The internal gear (510) includes an external gear (512) provided on one side of the drum (100) and an internal gear (514) meshed with the external gear (512). The external gear (512) is provided in the form of a ring gear along the circumference of the drum (100), and gear teeth are formed radially inward. The internal gear (514) has the form of a spur gear and is internally connected to the external gear (512). The driven gear (520) is connected to be concentric with the external gear (512). Specifically, as shown in FIG. 2, the drum (100) and the internal gear (510) are positioned inside the frame (600), and the driven gear (520) concentrically connected to the internal gear (514) is positioned outside the frame (600). The driven gear (520) outside the frame (600) meshes with the drive gear (220) of the drive shaft assembly (200).

[0040] Here are some important points about the gear connection between the drive gear (220) and the reduction gear (500). First, regarding the direction of rotation, the drive gear (220) and the driven gear (520) are connected in the form of spur gears, so their rotation directions are opposite to each other. In addition, the inner gear (514) that rotates coaxially with the driven gear (520) rotates in the same direction as the driven gear (520), and the outer gear (512) that is in contact with the inner gear (514) and the drum (100) having the outer gear (512) rotate in the same direction as the inner gear (514).

[0041] In conclusion, the entire reduction gear (500) and the drum (100) rotate in opposite directions with respect to the drive gear (220). For example, since the weight rises when the drum (100) rotates counterclockwise, the drive shaft assembly (200) must rotate clockwise for this purpose.

[0042] And, in terms of the configuration of the internal gear (510), the number of gear teeth of the internal gear (514) in the form of a spur gear is very small compared to the number of gear teeth of the external gear (512) in the form of a ring gear. Although the overall reduction ratio must include the number of gear teeth of the driving gear (220) and the driven gear (520), at least the configuration of the internal gear (510) greatly contributes to realizing a very large reduction ratio. Therefore, the winch (10) of the present invention can realize a high reduction ratio even with a compact design.

[0043] The ratchet assembly (400) is a known mechanism that prevents the drive shaft assembly (200) from rotating in only one direction to prevent a heavy object from falling freely due to its own weight. In the winch (10) of the present invention, since the heavy object descends when the drum (100) rotates clockwise, the ratchet assembly (400) prevents the drive shaft assembly (200) from rotating counterclockwise. More precisely, while the drive shaft assembly (200) rotates clockwise so that the winch (10) raises the heavy object, the ratchet assembly (400) does not allow the drive shaft assembly (200) to rotate counterclockwise. Therefore, the winch (10) can be safely used even while lifting a heavy object by the ratchet assembly (400).

[0044] The ratchet assembly (400) includes a ratchet wheel (410) and a pawl (420), and may additionally include an elastic means (422) to ensure reliable operation of the pawl (420). Due to the gear tooth inclination direction of the ratchet wheel (410) and the engagement direction of the pawl (420), the ratchet wheel (410) can only rotate in one direction that is not blocked by the pawl (420). Since this ratchet mechanism belongs to the category of well-known technology, a detailed description thereof will be omitted.

[0045] The ratchet wheel (410) is placed on the drive shaft (210) of the drive shaft assembly (200), and the pole (420) is installed on the frame (600). Therefore, the counterclockwise rotation of the drive shaft assembly (200) (i.e., the downward rotation of the weight) is restricted by the ratchet wheel (410), but the winch (10) of the present invention has a unique structure that allows the function of the ratchet assembly (400) to be exerted only during an operation of raising the weight. In other words, the winch (10) of the present invention automatically deactivates the ratchet assembly (400) during an operation of lowering the weight, thereby allowing the weight to be lowered quickly without interference from the ratchet assembly (400).

[0046] To this end, the ratchet wheel (410) is basically coupled so as to be able to rotate freely with respect to the drive shaft (210), and its location is the outer side of the drive gear (220) (the right side of the drive gear in the drawing). Instead, a threaded portion (230) is formed between the tip of the drive shaft (210) and the ratchet wheel (410), and a handle fixing nut (250) can be screwed into the threaded portion (230). To prevent the handle fixing nut (250) from coming off from the drive shaft (210), a flat washer (264) and a stop bolt (260) are mounted on the tip of the drive shaft (210). The flat washer (264) fixed by the stop bolt (260) forms a kind of catch, thereby preventing the handle fixing nut (250) from coming off.

[0047] In the illustrated embodiment, the stop bolt (260) is fastened to a screw hole (262) formed inside the tip of the drive shaft (210). In addition, the handle (300) for operating the winch (10) is coupled to the handle fixing nut (250). Specifically, the structure of the handle (300) is provided at one end of the handle (300) with a nut coupling member (310) that is fastened to the handle fixing nut (250), and an arm (320) extends radially from the nut coupling member (310). A grip member (330) that the operator holds by hand is provided at the free end of the arm (320). The handle fixing nut (250) and the nut coupling member (310) having corresponding shapes may form a shape, for example, an angular shape, in which the handle (300) does not rotate in place so that the torque according to the rotation of the arm (320) is fully applied to the drive shaft (210).

[0048] Fig. 5 illustrates a state in which a rope connected to a heavy object is wound around a drum (100) by rotating the handle (300) clockwise. As shown in Fig. 5, when the handle (300) is rotated clockwise, the handle fixing nut (250) rotates along the threaded portion (230) of the drive shaft (210). That is, by the clockwise rotation of the handle (300), the handle fixing nut (250) moves to the left in the drawing, which is the locking direction. When the handle fixing nut (250) moves to the left, the handle fixing nut (250) comes into contact with the ratchet wheel (410). Since the ratchet wheel (410) is inserted so as to be free to rotate with respect to the drive shaft (210), when the handle fixing nut (250) in contact with the ratchet wheel (410) continues to move to the left, the ratchet wheel (410) is pressed toward the drive gear (220) by the handle fixing nut (250).

[0049] When the handle fixing nut (250) is tightened to the extent that the ratchet wheel (410) pressed against the drive gear (220) no longer moves, the clockwise rotation of the handle (300) rotates the drive shaft (210) clockwise. FIG. 5 illustrates a state in which the drive shaft (210) is rotated clockwise by the handle (300). In this state, the ratchet wheel (410) is restrained on the drive shaft (210) (due to the frictional force between both the drive gear and the handle fixing nut), and the drum (100) rotates counterclockwise by the clockwise rotation of the drive shaft (210), and the weight is lifted.

[0050] In the state of Fig. 5, when the operation of the handle (300) is stopped, the load of the heavy object acts as a rotational force to turn the drive shaft (210) counterclockwise. However, since the drive gear (220) and the handle fixing nut (250) are in close contact with each other with the ratchet wheel (410) in the middle, the force to turn the drive gear (220) counterclockwise acts in the direction of tightening the handle fixing nut (250). In addition, since the ratchet wheel (410) is restrained on the drive shaft (210), the ratchet heel is restrained from rotating counterclockwise by the pawl (420). Therefore, even if the operation of the handle (300) is stopped while the heavy object is being raised, the counterclockwise rotation of the drum (100) is impossible, and thus the heavy object remains in place without falling.

[0051] In order for the operation of this ratchet assembly (400) to be performed stably, the ratchet wheel (410) needs to be firmly fixed on the drive shaft (210) by the frictional force caused by the tightening force of the handle fixing nut (250). To this end, a friction plate (430) may be installed on the drive shaft (210). The pair of friction plates (430) are located on both sides of the ratchet wheel (410). The pair of friction plates (430) increase the frictional force between the drive gear (220) and the ratchet wheel (410) and the frictional force between the ratchet wheel (410) and the handle fixing nut (250), respectively. Therefore, the ratchet wheel (410) rotates more firmly as one piece with the drive shaft (210) by the pair of friction plates (430).

[0052] FIG. 6 is a drawing illustrating a state in which the handle (300) is rotated counterclockwise to lower a heavy object. When the heavy object is raised, the drive shaft (210) is restricted from rotating counterclockwise by the operation of the ratchet assembly (400). Therefore, when the handle (300) is rotated counterclockwise to lower the heavy object, only the handle fixing nut (250) rotates counterclockwise and is released. However, once the handle fixing nut (250) is released, the ratchet wheel (410) with reduced friction becomes free, and the restraining force by the pawl (420) is no longer applied. Therefore, the drive shaft (210) rotates counterclockwise due to the load of the heavy object, and the heavy object is lowered accordingly.

[0053] In the state of Fig. 6, when the worker stops while holding the handle (300), the drive shaft (210) rotates counterclockwise while the handle fixing nut (250) is stopped. This state means that the drive shaft (210) is tightened with respect to the handle fixing nut (250). Of course, the drive shaft (210) does not move, but the handle fixing nut (250) is automatically locked to the left. However, the ratchet wheel (410) returns to the restrained state again by the tightening of the handle fixing nut (250). Therefore, even if the handle (300) is stopped while lowering a heavy object, the ratchet assembly (400) operates, thereby allowing the heavy object to be lowered safely. Of course, if you release your hand from the handle (300) or remove the handle (300) while the handle fixing nut (250) is loosened, the weight will descend to the end without stopping due to the weight of the weight, but for safety reasons, it may be desirable for the worker to operate the handle (300) to the end.

[0054] The above description has described the operation of the winch (10) for lifting a heavy load, focusing on the configuration of the drive shaft assembly (200), the reduction gear (500), and the drum (100). To supplement other configurations that have not been described, the winch (10) of the present invention includes a frame (600). The frame (600) refers to a structure that rotatably supports the drum (100), the drive shaft assembly (200), and the reduction gear (500). The frame (600) must have rigidity capable of withstanding the load applied to the drum (100), the drive shaft assembly (200), etc. A portion of the drum (100) is exposed outside the frame (600), and some side surfaces of the frame (600) are exposed. Through this, a worker can easily access the drum (100) to perform rope work, and can also perform simple maintenance work on the inside of the frame (600).

[0055] The above description applies to cases where the winch (10) operates normally, i.e., where the operator correctly operates the winch (10). However, in reality, cases of abnormal operation often occur due to operator error, misunderstanding, lack of skill, etc. In particular, problems may arise due to abnormal operation such as attempting to raise a heavy load while rotating the handle (300) counterclockwise.

[0056] Fig. 7 is a drawing showing a conventional winch (10'), in which the handle fixing nut (250) is in contact with the flat washer (264) by turning the handle (300) counterclockwise to the end (for convenience of explanation, the drawing symbols are kept the same). In the locked state where the handle fixing nut (250) is in contact with the flat washer (264) and cannot move any further to the right, the drive shaft (210) forms one body with the handle fixing nut (250) and rotates together.

[0057] If the handle (300) is turned counterclockwise in the initial state where the winch (10') does not lift the weight at all, that is, in a state where no load is applied to the drum (100), the state of FIG. 7 is reached, and if the handle (300) is continued to be turned counterclockwise in this state, the drum (100) will rotate clockwise and wind up the rope connected to the weight. Therefore, if the operator continues to turn the handle (300) counterclockwise due to a mistake or error during the initial operation of the winch (10'), the rope will be wound clockwise around the drum (100) and the weight will be lifted, although it is opposite to the rotation direction of the drum (100) during normal operation.

[0058] Such abnormal operation can cause a very dangerous situation not only for the winch (10') but also for the operator. That is, the winch (10') is designed to be able to slowly lower a heavy load with the help of the ratchet assembly (400) even with a relatively small force, but the abnormal operation of raising the heavy load by rotating the drive system of the winch (10') in the reverse direction is highly likely to cause irreversible damage or malfunction to the winch (10'). In addition, since the ratchet wheel (410) is completely free when the handle fixing nut (250) is in contact with the flat washer (264), and the ratchet function is thus deactivated, the operator must withstand the load of the heavy load with only his force. Therefore, this can cause a serious safety issue in which the heavy load is lowered rapidly due to the load.

[0059] The winch (10) of the present invention is designed to fundamentally resolve problems arising from such abnormal operation. Comparing the winch (10) of the present invention illustrated in FIG. 6 with FIG. 7, the winch (10) of the present invention has a smooth portion (240) formed in succession to the threaded portion (230) at the tip of the drive shaft (210). The diameter of the smooth portion (240) corresponds approximately to the diameter of the threaded portion (230), and its length corresponds approximately to the height of the handle fixing nut (250).

[0060] FIG. 8 illustrates a case where the handle (300) is continuously rotated counterclockwise in the winch (10) according to the present invention. By the rotation of the handle (300), the handle fixing nut (250) rotates counterclockwise along the threaded portion (230) of the drive shaft (210) and moves toward the front end of the drive shaft (210), i.e., to the right in the drawing. The handle fixing nut (250) moving along the threaded portion (230) reaches the smooth portion (240), and at the moment when the screw fastening to the threaded portion (230) is released, the handle fixing nut (250) is released from the threaded portion (230) and rotates idle on the smooth portion (240). That is, in the winch (10) of the present invention, the handle fixing nut (250) is brought into a free rotation state where it can no longer apply driving force to the drive shaft (210) due to the smooth portion (240) formed at the tip of the drive shaft (210). Therefore, in the winch (10) of the present invention, even if an abnormal operation is attempted to raise a heavy object by turning the handle (300) counterclockwise, the handle fixing nut (250) is fundamentally blocked from rotating the drum (100) by becoming one with the drive shaft (210).

[0061] Even if the handle fixing nut (250) moves to the smooth portion (240), the handle fixing nut (250) does not come off from the drive shaft (210) due to the flat washer (264) fixed with the stop bolt. In addition, the frictional force acting on the handle fixing nut (250) and the threaded portion (230) is designed to be smaller than the load acting on the drive shaft (210) through the drum (100), so that the handle fixing nut (250) is surely released with respect to the threaded portion (230) during the operation of turning the handle (300) counterclockwise. For example, the frictional force acting on the handle fixing nut (250) and the threaded portion (230) is designed to be smaller than the force acting on the drive shaft (210) due to the load of a heavy object.

[0062] Fig. 9 is a perspective view illustrating the coupling structure of a handle fixing nut (250) to a drive shaft (210) in a winch (10) of the present invention. Referring to Fig. 9, a compression spring (270) is arranged in a smooth portion (240). Specifically, the compression spring (270) is arranged between the handle fixing nut (250) and a flat washer (264).

[0063] In this structure where the compression spring (270) is interposed, the handle fixing nut (250) receives a force pushing toward the threaded portion (230) by the elastic force of the compression spring (270). That is, when the handle (300) is rotated counterclockwise, resistance is applied by the compression spring (270) while moving from the threaded portion (230) to the smooth portion (240), but since the elastic force of the compression spring (270) is much smaller than the manpower for operating the handle (300), the handle fixing nut (250) easily moves to the smooth portion (240).

[0064] However, since the handle fixing nut (250) on the smooth portion (240) is pressed against the beginning of the threaded portion (230) due to the elasticity of the compression spring (270), the handle fixing nut (250) can enter the threaded portion (230) immediately when the operator rotates the handle (300) clockwise. In this way, by arranging the compression spring (270) between the handle fixing nut (250) and the flat washer (264), the handle fixing nut (250) automatically enters the threaded portion (230) in response to the normal operation of rotating the drive shaft (210) clockwise to lift a heavy object. Therefore, the winch (10) of the present invention allows the operator to conveniently use the winch (10) even though the smooth portion (240) that deactivates winch operation is formed at the end of the drive shaft (210).

[0065] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. A drum on which the rope is wound; A drive shaft assembly including a drive shaft that rotates by torque transmitted through a handle, a drive gear fixed on the drive shaft, a handle fixing nut that is screwed into a threaded portion formed on the drive shaft, and a flat washer that is fixedly installed to the tip of the drive shaft to prevent the handle fixing nut from coming off; A ratchet assembly including a ratchet wheel installed on the drive shaft so as to be freely rotatable between the drive gear and the handle fixing nut, and a pawl that restrains the ratchet wheel so as to rotate in only one direction; and A reduction gear including a plurality of gears connected so that the rotation of the driving gear is reduced and transmitted to the drum; Including, The ratchet wheel restrains the drive shaft to rotate only in one direction by the pawl when the ratchet wheel can rotate together with the drive shaft by frictional force caused by tightening the handle fixing nut, A winch in which a smooth portion is formed between the tip of the driving shaft and the threaded portion, and when the handle fixing nut rotates counterclockwise and moves from the threaded portion to the smooth portion, the handle fixing nut is in a state in which it can rotate freely.

2. In paragraph 1, The above smoothing part, A winch whose diameter corresponds to the diameter of the screw thread and whose length corresponds to the height of the handle fixing nut.

3. In paragraph 1, A winch in which the frictional force acting on the handle fixing nut and screw thread is smaller than the load acting on the drive shaft through the drum.

4. In paragraph 1, The above drive shaft assembly, A winch further comprising a compression spring disposed between the handle fixing nut and the flat washer on the drive shaft.

5. In paragraph 4, The above compression spring, A winch that applies an elastic force to press the handle fixing nut toward the threaded portion when the handle fixing nut is in a state where it can rotate freely on the smooth portion.

6. In paragraph 5, A winch in which the compression spring presses the handle fixing nut against the beginning of the threaded portion, and thus screw fastening to the threaded portion is initiated as soon as the handle fixing nut rotates clockwise.

Images