Brake device, lever block and ratchet mechanism

Abstract

The invention provides a brake device, a lever block and a ratchet mechanism which can prevent a ratchet from reversing even if a switching knob is mistakenly operated towards a rewinding direction side during winding. A brake device (70) is provided with: a brake bracket (71) which is supported so as not to rotate by a drive shaft (25) and which has a flange section (71a) and a boss section (71b); a female screw member (35) that is axially supported by the boss section (71b) and that is screwed to a male screw section (26) on the outer periphery of the drive shaft (25); a ratchet wheel (80) which is sandwiched between the flange part (71a) and the female screw member (35) that face each other, and which has ratchet teeth (83) that restrict the rotation direction in one direction on the outer peripheral side; brake plates (71a, 72b) disposed between the ratchet wheel (80) and at least one of the flange portion (71a) and the female screw member (35); and a pair of pawl members (90) that mesh with the ratchets (83) and are disposed at symmetrical positions centered on the drive shaft (25). The ratchet wheel (80) is provided with high teeth (831) and low teeth (832), wherein the protruding height of the low teeth (832) from the center is lower than that of the high teeth (831).

Description

[0001] (This application is a divisional application of the patent application filed by Kaido Co., Ltd., Chinese application number 202180028007.2, filed on January 28, 2021, entitled "Brake device, lever hoist and ratchet mechanism".) Technical Field

[0002] This invention relates to braking devices, lever hoists, and ratchet mechanisms. Background Technology

[0003] Hand lever hoists are widely used for lifting, pulling, and securing goods using chains or similar methods. By manually operating the lever, the chain can be wound up (coiled) and unwound (unwound). One type of hand lever hoist is shown in Patent Document 1. In the hand lever hoist disclosed in Patent Document 1, operating the lever drives a drive unit, which in turn rotates the drive shaft, thereby rotating the load pulley. This allows for lifting or unloading of goods. Furthermore, the hand lever hoist is equipped with a switching knob, which allows switching between the direction of the driving force transmitted from the lever—either in the winding or unwinding direction.

[0004] [Existing Technical Documents]

[0005] [Patent Documents]

[0006] Patent Document 1: Japanese Patent Publication No. 2011-102182 Summary of the Invention

[0007] (The problem that the invention aims to solve)

[0008] However, if the switching knob is mistakenly switched to the winding direction when the lever hoist is in operation, the braking mechanism may not function. Specifically, if the switching knob is mistakenly switched to the winding direction while the front end of the pawl is in contact with the tip of the ratchet teeth, the ratchet may start to rotate violently under the load of the cargo.

[0009] If the tip of the pawl component enters the tooth groove between the ratchet teeth during the initial rotation of the ratchet, the ratchet's rotation can be stopped. However, if the switch knob is turned and the ratchet rotates violently while the tip of the pawl component is abutting the tip of the ratchet tooth, the next ratchet tooth will arrive earlier than required to enter the tooth groove. The pawl component will collide with the tip of the next tooth and bounce off, and the same situation will occur again. The tip of the pawl component will not enter the tooth groove, and thus the ratchet's rotation may not be stopped. The structure disclosed in Patent Document 1 cannot prevent the rotation of such a ratchet.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a braking device, a lever hoist and a ratchet mechanism that can prevent the ratchet from reversing.

[0011] (A solution to the problem)

[0012] To solve the above-mentioned problems, according to a first aspect of the present invention, a braking device is provided that prevents the reverse rotation of the load pulley by stopping the reverse rotation of the drive shaft that transmits rotation to the load pulley around which the chain is wound.

[0013] The braking device has the following characteristics.

[0014] It comprises: a brake bracket supported on a drive shaft in a non-rotatable manner, and having a flange portion and a bushing portion; a female threaded component supported on the drive shaft in a rotatable manner and screwed into a male threaded portion disposed on the outer periphery of the drive shaft; a ratchet held by opposing flange portions and female threaded components, and having ratchet teeth on its outer periphery for limiting the direction of rotation to one direction; a brake plate disposed between at least one of the flange portion and the female threaded component and the ratchet; and at least one pawl component whose front end engages with a tooth valley portion located between adjacent ratchet teeth and meshes with the ratchet teeth; the ratchet is provided with high teeth and low teeth whose protrusion height from the center of rotation of the ratchet is lower than that of the high teeth.

[0015] In addition, another preferred aspect of the present invention is that, in the above-described invention, a pair of pawl components are provided, and the pair of pawl components are arranged symmetrically about the drive shaft.

[0016] Furthermore, another preferred aspect of the present invention is that, in the above-described invention, the ratchet is alternately provided with high teeth and low teeth.

[0017] Furthermore, another preferred aspect of the present invention is that, in the above-described invention, the number of ratchet teeth is an odd number of twice.

[0018] Furthermore, another preferred aspect of the present invention is that, in the above-described invention, the tip portion of the low tooth on the tip side is formed as part of an arc.

[0019] In addition, in order to solve the above-mentioned problems, according to a second aspect of the present invention, a lever hoist is provided, which has the following features.

[0020] The invention includes the braking device described above, and further comprises: an operating lever that rotates relative to the female threaded component; a winding switching pawl mounted on the operating lever and engaging with a switching gear in the winding direction, the switching gear being integral with the female threaded component; a rewinding switching pawl mounted on the operating lever and engaging with the switching gear in the rewinding direction; and a switching knob integrally provided with the winding switching pawl and the rewinding switching pawl, and for switching which of the two switching pawls engages with the switching gear.

[0021] In addition, in order to solve the above-mentioned problems, according to a third aspect of the present invention, a ratchet mechanism is provided, which allows the ratchet to rotate in only one direction by having a ratchet with a plurality of ratchet teeth formed on its outer periphery and at least one pawl member that engages with the ratchet teeth. The ratchet mechanism is characterized in that the ratchet teeth include high teeth and low teeth whose protrusion height from the center of rotation of the ratchet is lower than that of the high teeth.

[0022] (Invention effect)

[0023] According to the present invention, a braking device, a lever hoist, and a ratchet mechanism are provided that can prevent the ratchet from reversing even if the switching knob is accidentally operated in the rewinding direction when winding up. Attached Figure Description

[0024] Figure 1 This is a front view showing an example structure of a lever hoist equipped with a power transmission device for lever hoists according to the present invention.

[0025] Figure 2 It means Figure 1 The diagram shows a cross-sectional view of the structure of a lever hoist.

[0026] Figure 3 It is an enlarged representation Figure 1 A partial cross-sectional view of the area near the braking device in the lever hoist shown.

[0027] Figure 4 It means Figure 1 The diagram shows a top view of the ratchet and pawl components in a lever hoist, and is a diagram showing the state with an odd number of ratchet teeth that is twice the number of ratchet teeth.

[0028] Figure 5 yes Figure 4 A magnified view of the area near the ratchet teeth of the ratchet shown.

[0029] Figure 6 It means Figure 1The diagram shows a top view of the ratchet and pawl components in a lever hoist, and is a diagram showing the state with an even number of ratchet teeth, which is twice the number of ratchet teeth. Detailed Implementation

[0030] Hereinafter, a lever hoist 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0031] <About the overall structure of a lever hoist>

[0032] In the following description, the X direction is defined as the axial direction of the drive shaft 25 disposed between the gearbox (symbol omitted) and the quick-turn handle 60 (hereinafter referred to as the "idle handle"). The gearbox contains a reduction gear 30. The X1 side is defined as the side on which the idle handle 60 is mounted, and the X2 side is the gearbox side opposite to it. In addition, the Z direction is defined as the vertical direction (suspension direction; winding direction) of the lever hoist 10 in the suspended state. The Z1 side is defined as the upper side in the suspended state, and the Z2 side is defined as the lower side in the suspended state.

[0033] Figure 1 This is a front view showing an example structure of the lever hoist 10. Figure 2 It means Figure 1 The diagram shows a cross-sectional view of the structure of the lever hoist 10.

[0034] like Figure 2 As shown, the lever hoist 10 includes a pair of frames 11 and 12, with an upper hook 22 supported on the upper side (Z1 side) of the pair of frames 11 and 12. Additionally, a load sheave 20 for hanging chain C1 is supported between the pair of frames 11 and 12 in a rotatable state. A load gear 21 is integrally formed on the load sheave 20, meshing with the small-diameter gear portion 32 of the reduction gear 30 (described later). Furthermore, an axial through-hole 20a is formed in the load sheave 20, through which the drive shaft 25 is inserted. A male thread portion 26, meshing with the female threaded component 35 (described later), is provided on the outer periphery of the drive shaft 25, and a small gear 27, meshing with the large-diameter gear portion 31 of the reduction gear 30, is provided at the other end (X2 side) of the drive shaft 25. Additionally, a small-diameter gear portion 32, meshing with the load gear 21, is integrally formed on the reduction gear 30.

[0035] Additionally, a housing 13 is mounted on the frame 11 to protect the drive components such as the reduction gear 30 or load gear 21. Furthermore, the male threaded portion 26 engages with the female threaded portion 36 of the female threaded component 35. In this female threaded component 35, in addition to the female threaded portion 36, a switching gear 37 is provided on its periphery, which engages with a switching pawl 40 at a lower position (Z2 side). The switching pawl 40 is, for example, a pawl provided on one side and the other side of the operating lever 50 (described later). By rotating the operating lever 50 while the switching pawl 40 is engaged with the switching gear 37, driving force is transmitted to the female threaded component 35.

[0036] Additionally, a switching knob 45 is mounted coaxially with the switching pawl 40. By switching the knob 45, the transmission of driving force to the female threaded component 35 can be switched to either the winding direction or the rewind direction. For example, if the lower side (Z2 side) of the switching knob 45 is pushed towards... Figure 1 On the left side, the switching pawl 40 for winding engages with the switching gear 37. Thus, when the operating lever 50 is repeatedly rotated, the switching gear 37 rotates in the winding direction but not in the rewinding direction. This corresponds to the winding state of chain C1.

[0037] Moreover, such as Figure 1 As shown, a pair of engaging protrusions 46 are provided on the upper side (Z1 side) of the aforementioned switching knob 45. By engaging one of these engaging protrusions 46 with the flange 65 of the idling handle 60, the idling handle 60 will not be pulled out to the axial (X direction) side (X1 side). Therefore, the state of the force-applying spring-pressing braking mechanism (not shown) can be maintained.

[0038] On the other hand, for example, if the lower side (Z2 side) of the switching knob 45 is pushed towards Figure 1 On the right side, the switching pawl 40 for winding engages with the switching gear 37. Thus, when the operating lever 50 is repeatedly rotated, the switching gear 37 rotates in the winding direction but not in the coiling direction. This corresponds to the winding state of chain C1. Furthermore, by engaging another engaging protrusion 46 with the flange 65 of the idler handle 60, the idler handle 60 is not pulled out to the axial (X direction) side (X1 side). Therefore, the state of the force-applying spring-pressing brake mechanism (not shown) can be maintained.

[0039] Furthermore, if the lower side (Z2 side) of the switching knob 45 is positioned between the winding direction and the rewinding direction, i.e., in a neutral position (in this case, the switching knob 45 is positioned along the length of the operating lever 50), then neither the switching pawl 40 for winding nor the switching pawl 40 for rewinding will engage with the switching gear 37. Thus, even if the operating lever 50 is rotated, neither the winding nor rewinding of chain C1 will occur; this is a free (idling) state. At this time, neither of the pair of engaging protrusions 46 engages with the flange 65 of the idle handle 60. Therefore, the idle handle 60 can be pulled out to one side (X1 side) in the axial direction, thereby loosening the force-applying spring-pressing brake mechanism (not shown in the figure).

[0040] Additionally, a cam component 55 is mounted on the drive shaft 25 in a non-rotatable state relative to the drive shaft 25. Furthermore, a component called a freewheeling handle 60 is also mounted at a position (X1 side) further axially (X direction) than the cam component 55, in a non-rotatable state relative to the drive shaft 25.

[0041] The idler handle 60 is a generally circular handle-shaped portion that can rotate with the drive shaft. A flange 65 is provided on the opposite side (X2 side) of the idler handle 60 in the axial direction (X direction). When either of the pair of engaging protrusions 46 engages with the flange 65, the idler handle 60 cannot be pulled out to the axial (X direction) side (X1 side). Therefore, the state of the force-applying spring-pressing braking mechanism (not shown) can be maintained.

[0042] like Figure 2 As shown, the idler handle 60 is pressed in towards the other side (X2 side) in the axial direction (X direction) when winding up and when rewinding. However, when the switching knob 45 is in the neutral position (neutral state), the idler handle 60 can be pulled out towards the side (X1 side) in the axial direction (X direction). When the idler handle 60 is pulled out towards the side (X1 side) in the axial direction (X direction), the pressing force of the force spring that applies force to the braking mechanism is reduced, thereby changing to the brake release state. As a result, the chain C1 can be freely pulled out in either direction of the winding side or the rewinding side while holding the chain C1 by hand or the like.

[0043] <Regarding the braking device 70>

[0044] Figure 3 It is an enlarged representation Figure 1 A partial cross-sectional view of the area near the braking device 70 in the lever hoist shown. Figure 2 and Figure 3As shown, a braking device 70 is disposed between the operating lever 50 and the drive shaft 25. The braking device 70, as a main structural element, includes: a brake bracket 71, brake plates 72a and 72b, a ratchet 80, a pawl assembly 90, a pawl shaft 91, a bushing 92, etc.

[0045] The brake bracket 71 has a flange portion 71a and a hollow bushing portion 71b (corresponding to the bushing portion (boss)). The flange portion 71a is configured to have a diameter larger than that of the hollow bushing portion 71b, and it is able to abut against the brake plate 72a.

[0046] The hollow bushing portion 71b is located further from the female threaded member 35 (X1 side) than the flange portion 71a, and it supports the ratchet 80 via the bushing 92. In addition, the inner circumference of the hollow bushing portion 71b engages with the drive shaft 25 via a key connection or spline connection, thereby allowing the drive shaft 25 and the brake bracket 71 to rotate integrally.

[0047] Furthermore, brake plates 72a and 72b are axially supported on the hollow bushing portion 71b between the flange portion 71a and the ratchet 80, and between the internal threaded component 35 and the ratchet 80, respectively. The brake plates 72a and 72b are friction members formed, for example, by sintering a specified material.

[0048] Here, when a load is applied to the drive shaft 25 in the winding direction, the female threaded member 35 presses down on the brake plates 72a and 72b through the threaded fastening action between the female threaded member 35 and the brake bracket 71 (flange 71a). As a result, the brake plates 72a and 72b are forcefully pressed down, and the ratchet 80 is also forcefully pressed down by the brake plates 72a and 72b. Here, since the ratchet pawl member 90 is locked onto the ratchet 80, thus preventing the ratchet 80 from rotating in the winding direction, the rotation of the drive shaft 25 in the winding direction is suppressed by the aforementioned forceful pressing.

[0049] Furthermore, if the switching knob 45 is switched to the winding direction and the operating lever 50 is operated, the ratchet 80 can rotate in the winding direction, and therefore, this rotation in the winding direction will not be blocked by the ratchet 80. Thus, by operating the operating lever 50, the female threaded component 35, brake plates 72a and 72b, ratchet 80, and brake bracket 71 become a single unit, causing the drive shaft 25 to rotate. Its driving force is transmitted to the load pulley 20 via the reduction gear 30, thereby winding up the chain C1.

[0050] On the other hand, when the switching knob 45 is switched in the rewinding direction and the operating lever 50 is operated, the female threaded component 35 rotates by an amount corresponding to the operation amount, thereby easing the thread tightening action of the brake bracket 71. Therefore, the braking force on the ratchet 80 is released corresponding to the operation amount of the operating lever 50 (i.e., the rotation amount of the female threaded component 35), thus causing the brake bracket 71 and the drive shaft 25 to rotate in the rewinding direction. This driving force in the rewinding direction is transmitted to the load pulley 20 via the reduction gear 30, thereby causing the chain C1 to rewind.

[0051] Additionally, the ratchet teeth 83 (described later) provided on the ratchet 80 engage with the front end 90a of the pawl component 90. This engagement constitutes a ratchet mechanism configured such that, except when the switching knob 45 is switched in the winding direction and the operating lever 50 is operated, the ratchet 80 is prevented from rotating in the winding direction and is allowed to rotate in the coiling direction.

[0052] In addition, such as Figure 3 As shown, a bushing 92 is provided on the outer periphery of the hollow bushing portion 71b of the brake bracket 71, and a ratchet 80 is provided on the outer periphery of the bushing 92.

[0053] Furthermore, a pawl shaft 91 is mounted on the frame 12, and the pawl component 90 is rotatably supported on the pawl shaft 91. A coil portion 93a of a torsion spring 93 is mounted on the pawl shaft 91, and the torsion spring 93 applies a force in the direction that presses the pawl component 90 against the ratchet tooth 83 (described later) of the ratchet wheel 80. Additionally, a pair of pawl components 90 are provided, which are arranged point-symmetrically with respect to the central axis of the drive shaft 25 in the circumferential direction of the ratchet wheel 80.

[0054] <About Ratchet 80>

[0055] Next, the structure of ratchet 80 will be explained. Figure 4 This is a top view showing the ratchet 80 and the pawl component 90, and is a diagram illustrating an example structure where the number of ratchet teeth 83 is an odd multiple of twice, and is also a top view showing the configuration of the pawl component 90. (See diagram below.) Figure 4 As shown, an annular portion 81 is provided on the ratchet 80, the surface and back of which are pressed by the brake plates 72a and 72b. Furthermore, by positioning the bushing 92 in the central hole 82 at the center of the annular portion 81, the ratchet 80 is supported for free rotation.

[0056] A ratchet 83 protrudes from the annular portion 81 toward the outer periphery. Figure 5 This is a magnified view of the area near ratchet tooth 83 of ratchet 80. (See image below.) Figure 5As shown, the ratchet 83 includes a high tooth 831 and a low tooth 832. The tip of the high tooth 831 (high tooth tip 831a) protrudes further outward than the tip of the low tooth 832 (low tooth tip 832a). Therefore, the front end 90a of the pawl member 90 is configured such that, under the force of the torsion spring 93, the position where the front end 90a contacts the low tooth tip 832a is closer to the radial center (inner diameter) than the position where it contacts the high tooth tip 831a.

[0057] In this embodiment, high teeth 831 and low teeth 832 are formed alternately adjacent to each other, and their circumferential lengths (tooth pitch) are set to be equal. Furthermore, when the portion between high teeth 831 and low teeth 832 is designated as a tooth valley 833, the inclination angle of the tapered portion 831b of the high tooth tip portion 831a from the tooth valley 833 toward the tip side of the high tooth 831 is set to be equal to the inclination angle of the tapered portion 832b of the low tooth tip portion 832a from the tooth valley 833 toward the tip side of the low tooth 832. Therefore, in this embodiment, the low tooth 832 is configured such that the tip side of the high tooth 831 is cut off. Additionally, the low tooth tip portion 832a of the low tooth 832 can also be part of an arc concentric with the ratchet 80. However, the low tooth tip portion 832a can also be a shape other than part of an arc (e.g., a straight line), or it can be part of an arc not concentric with the ratchet 80.

[0058] Furthermore, the number of teeth in the ratchet 83, after combining the high teeth 831 and the low teeth 832, is an even number. Here, as... Figure 4 As shown, when the number of teeth on the ratchet 83 is an odd multiple of 2, when the front end 90a of one pawl member 90 is pressed against the high tooth 831, the other pawl member 90 is pressed against the low tooth 832. Since either one pawl member 90 or the other pawl member 90 must be pressed against the low tooth 832, when reversal occurs, at least the front end 90a of the pawl member 90 pressed against the low tooth 832 must collide with the high tooth 831 (back side) adjacent to that low tooth. Therefore, reversal of the ratchet 80 can be reliably prevented. Furthermore, in Figure 4 In the structure shown, the ratchet 83 has a total of 22 teeth, but the number of teeth in the ratchet 83 can be any number as long as it is twice an odd number.

[0059] However, as Figure 6As shown, when the number of teeth in the ratchet 83, which includes both high teeth 831 and low teeth 832, is a multiple of an even number (a multiple of 4), when the front end 90a of one pawl member 90 is pressed against the high tooth 831, the other pawl member 90 is also pressed against the high tooth 831. Similarly, when the front end 90a of one pawl member 90 is pressed against the low tooth 832, the other pawl member 90 is also pressed against the low tooth 832. In this case, when reversal occurs, the front end 90a of the pawl member 90 pressed against the low tooth 832 will inevitably collide with the back of the high tooth 831 adjacent to that low tooth, or, regarding the front end 90a of the pawl member 90 pressed against the high tooth 831, since the spacing between adjacent high teeth 831 is larger than the spacing of ratchet teeth of the same height in the conventional ratchet, it is possible to sufficiently prevent the ratchet 80 from reversing. Furthermore, in Figure 6 In the structure shown, the ratchet 83 has a total of 20 teeth, but the number of teeth in the ratchet 83 can be any number as long as it is twice an even number.

[0060] <Regarding effects>

[0061] The braking device 70 and the lever hoist 10 configured as described above include: a brake bracket 71, which is non-rotatably supported on the drive shaft 25 and has a flange portion 71a and a hollow bushing portion 71b (shoulder portion); a female threaded member 35, which is rotatably supported on the drive shaft 25 and is screwed into a male threaded portion 26 provided on the outer periphery of the drive shaft 25; and a ratchet 80, which is held by the opposing flange portion 71a and the female threaded member 35, and has a ratchet on its outer periphery. The ratchet 83 restricts the rotation direction to one direction; brake plates 72a and 72b are disposed between at least one of the flange portion 71a and the female threaded member 35 and the ratchet 80; and at least one pawl member 90 engages with the ratchet 83, and its front end 90a (front end side) engages with the tooth valley portion 833 located between adjacent ratchet teeth 83; the ratchet 80 is provided with a high tooth 831 and a low tooth 832 whose protrusion height from the center of rotation of the ratchet 80 is lower than that of the high tooth 831.

[0062] Here, consider the case where the switching knob 45 is mistakenly switched to the winding direction while the front end 90a of the pawl member 90 is in contact with the tip 831a of the high tooth 831. In this case, under the load of the cargo, the ratchet 80 will begin to rotate violently (reverse). However, as described above, the ratchet 80 has a high tooth 831 and a low tooth 832. Therefore, the front end 90a of the pawl member 90, after passing the tip 832a of the low tooth 832, collides with the back of the high tooth 831 adjacent to the low tooth, thus preventing the ratchet 80 from reversing.

[0063] Furthermore, in this embodiment, it is preferable to alternately provide high teeth 831 and low teeth 832 on the ratchet 80. With this configuration, when the front end 90a of at least one pawl member 90 contacts the tip 832a of the low tooth 832, if the ratchet 80 begins to rotate (reverse), it immediately collides with the back of the high tooth 831, which is the next tooth. Additionally, when the front end 90a of at least one pawl member 90 contacts the tip 831a of the high tooth 831, even if the ratchet 80 begins to rotate (reverse) and passes the tip 832a of the low tooth, it immediately collides with the back of the high tooth 831. Therefore, reversal of the ratchet 80 can be prevented at an earlier stage.

[0064] Furthermore, in this embodiment, it is preferable that the number of ratchet teeth 83 is an odd multiple of 2. With this configuration, when the front end 90a of one pawl member 90 is pressed against the high tooth 831, the other pawl member 90 is pressed against the low tooth 832. By ensuring that either one pawl member 90 or the other pawl member 90 is pressed against the low tooth 832, even if the ratchet 80 reverses at a speed exceeding the intended speed, the front end 90a of one of the pawl members 90 can be pressed against the tip of the low tooth 832a in the ratchet 80, which is located on the inner diameter side of the ratchet 80, compared to the tip of the high tooth 831a. Therefore, the reversal of the ratchet 80 can be reliably prevented.

[0065] Furthermore, in this embodiment, the low tooth tip portion 832a on the low tooth 832 tip side can be configured to form a portion of an arc. With this configuration, the circumferential length of the low tooth tip portion 832a is longer than the circumferential length of the high tooth tip portion 831a. Therefore, compared to the high tooth tip portion 831a, the contact time between the front end 90a of the pawl member 90 and the low tooth tip portion 832a can be prolonged, thus more reliably preventing the ratchet 80 from reversing. Additionally, since the low tooth tip portion 832a can be easily machined using, for example, a machine tool, productivity can be improved.

[0066] <Variation Example>

[0067] The various embodiments of the present invention have been described above, but the present invention can be modified in various ways. These will be described below.

[0068] In the above embodiment, an idling device for switching between idling and non-idling is described by operating the idling handle 60, but it may also be a lever hoist with other idling devices such as automatic idling mode.

[0069] Furthermore, in the above embodiment, the application of the braking device 70 to the lever hoist 10 has been described. However, the above-described braking device can also be applied to winches other than lever hoists, such as chain hoists.

[0070] Furthermore, in the above embodiment, the case with a pair of pawl members 90 has been described. However, regarding the pawl members 90, only one or more may be provided. When three or more pawl members 90 are provided, it is preferable that the pawl members 90 are evenly arranged on the outer periphery of the ratchet 80, and that when one pawl member 90 engages with the tooth valley between the ratchet teeth adjacent to the high teeth, another pawl member 90 engages with the tooth valley between the ratchet teeth adjacent to the low teeth.

[0071] However, the multiple pawl components 90 may not be evenly distributed on the outer periphery of the ratchet 80. In this case, it is preferable to arrange them such that the radial forces acting on the pawl shaft 21 of each pawl component 90 are equal. For example, when four pawl components 90 are provided, each pair of pawl components 90 may be arranged in a line symmetrical about a line perpendicular to the drive shaft 25. By arranging the four pawl components 90 such that the radial forces acting on their pawl shaft 21 are equal, the forces acting on the ratchet 80 from the pawl components 90 are distributed, thereby improving the durability of the ratchet 80. In addition, by arranging the pawl components 90 in this way, the deviation of the forces acting on the drive shaft 25 from the ratchet 80 can be reduced, and as a result, the durability of the drive shaft 25 or its surrounding components can also be improved.

[0072] Furthermore, the most preferred configuration is a pair of pawl components 90, arranged in a point-symmetric position about the drive shaft 25 with the same shape. However, the pawl components 90 can also be formed in different shapes as long as the front ends 90a of each pawl component 90 simultaneously engage with their respective tooth grooves 833. For example, by evenly arranging two or more pawl components 90 on the outer periphery of the ratchet 80, the force applied to one pawl component 90 can be distributed, and the radial force applied to the pawl shaft 91 on which the ratchet 80 is arranged can be reduced. Ideally, the engagement positions of the front ends 90a are point-symmetric. Although they could also be staggered by an even number of teeth, if the staggering amount increases, the load applied to the drive shaft 25 increases, so the required staggering of the engagement positions is not ideal.

[0073] In addition, in the above embodiment, the brake plate 72 and the ratchet 80 are configured as separate parts, but friction components can also be formed by sintering on both sides of the ratchet 80.

[0074] Furthermore, in the above embodiment, the female threaded component 35 of the ratchet 80 is pressed by the load torque acting on the drive shaft 25, and the male threaded portion 26 of the drive shaft 25 is configured to engage with the female threaded portion 36 of the female threaded component 35. However, the female threaded component 35 can be configured to be separate from the drive shaft 25 (for example, a male thread provided on the outer periphery of the hollow shaft formed by extending the hollow bushing portion 71b of the brake bracket 71), and further, it can also be a mechanism that uses a cam to convert the load torque into axial force.

[0075] Furthermore, in the above embodiments, the braking device 70 of the lever hoist 10 was described as an example. However, if the present invention is understood more broadly, it can also be said to relate to a ratchet mechanism. That is, the ratchet mechanism of the present invention allows the ratchet to rotate in only one direction by having a ratchet with a plurality of teeth formed on its outer periphery and at least one pawl member that engages with the ratchet teeth. In this ratchet mechanism, the ratchet teeth include high teeth with a high protrusion height from the center of the ratchet and low teeth with a low protrusion height from the center of the ratchet.

[0076] By configuring the ratchet mechanism in this way, even if a reversal occurs when the front end of the pawl component is at the tip of a high or low tooth, the front end of the pawl component will at least collide with the back of the next high tooth (the inclined portion forming the high tooth) and enter the tooth valley between the ratchet teeth. Therefore, the reversal of the ratchet can be stopped immediately and reliably.

[0077] Here, as Figure 4 As shown, the two pawl components are preferably positioned symmetrically. Furthermore, it is preferable that the high teeth and low teeth alternate. Additionally, it is preferable that the number of ratchet teeth is an odd multiple of 2.

[0078] Furthermore, by placing the two pawl components in symmetrical positions, deviations in the stress applied to the ratchet can be eliminated. Additionally, by alternating between high and low teeth, when a reversal occurs, the tip of the pawl component collides with the back of the nearest high tooth. Moreover, by setting the number of ratchet teeth to an odd multiple of twice, when the tip of one pawl component in a symmetrical position is at the tip of a high tooth, the tip of the other pawl component is at the tip of a low tooth. Therefore, when a reversal occurs, at least the tip of the pawl component at the tip of a low tooth will collide with the back of the high tooth adjacent to that low tooth, thus immediately and reliably preventing the ratchet from reversing.

[0079] Such a ratchet mechanism is used, for example, in the braking device of a lever hoist that resists input torque in one direction, as described in the above embodiments, and is particularly effective in preventing the ratchet constituting the braking device from reversing.

[0080] (Symbol Explanation)

[0081] 10… lever hoist

[0082] 11…Framework

[0083] 12…framework

[0084] 13…shell

[0085] 20…load pulley

[0086] 20a… Through hole

[0087] 21…load gear

[0088] 22… Upper hook

[0089] 25… drive shaft

[0090] 26…male thread section

[0091] 27…small gear

[0092] 30…reduction gear

[0093] 31…Large Diameter Gear Section

[0094] 32…Small Diameter Gear Section

[0095] 35…Female threaded component

[0096] 36…Female thread section

[0097] 37… Switch gears

[0098] 40… Switch to ratchet

[0099] 45… Switch knob

[0100] 46… (The text abruptly ends here, likely due to an incomplete sentence or a formatting error.)

[0101] 50… control lever

[0102] 55… Cam component

[0103] 60…Freewheel handle

[0104] 65…Flange

[0105] 70…Brake device

[0106] 71…Brake bracket

[0107] 71a…Flange portion

[0108] 71b… Hollow bushing portion (corresponding to bushing portion)

[0109] 72a…brake plate

[0110] 72b…brake plate

[0111] 80…Ratchet

[0112] 81… Circular portion

[0113] 82…Center Hole

[0114] 83…Ratchet

[0115] 90…Pawl component

[0116] 90a…front end

[0117] 91…Pawl Axis

[0118] 92… Bushing

[0119] 93… Torsion Spring

[0120] 93a…coil section

[0121] 831…High-speed teeth

[0122] 831a…High tooth tip

[0123] 831b…conical part

[0124] 832…lower teeth

[0125] 832a…low tooth tip

[0126] 832b…conical part

[0127] 833…Kigube

[0128] C1…chain

Claims

1. A ratchet mechanism comprising a ratchet with a plurality of teeth formed on its outer periphery and at least two pawl components engaging with the teeth, thereby allowing rotation of the ratchet in only one direction. The ratchet mechanism is characterized in that... The ratchet has high teeth and low teeth whose projection height from the center of rotation of the ratchet is lower than that of the high teeth. On the ratchet, high teeth and low teeth are alternately arranged, adjacent to each other, and the tooth pitch in the circumferential direction is set to be equal. When one of the pawl components engages with the tooth valley located between adjacent ratchet teeth, at the same time, at least one other pawl component engages with another tooth valley located between adjacent ratchet teeth.

2. The ratchet mechanism according to claim 1, characterized in that, When one of the pawl components engages with the tooth valley located on the back side of the high tooth, at least one other pawl component engages with another tooth valley located on the back side of the low tooth.

3. The ratchet mechanism according to claim 1 or 2, characterized in that, The two pawl components are positioned symmetrically about the axis of rotation.

4. The ratchet mechanism according to claim 3, characterized in that, The ratchet teeth are provided in an odd number of times twice the number of teeth.

5. The ratchet mechanism according to any one of claims 1 to 4, characterized in that, The tip of the low tooth on the tip side is formed as part of an arc.

Images