Chain block

Abstract

Provided is a chain block capable of ensuring a sufficient speed reduction ratio without increasing in size.　A chain block 10 comprises: a first gear speed reduction portion G1 comprising a drive shaft 40, a pinion gear 46 provided on the other side in the axial direction of the drive shaft 40, and a first gear 63 engaged with the pinion gear 46 to decelerate the drive speed; a second gear speed reduction portion G2 comprising a second gear 64 that is provided on the other side in the axial direction relative to the first gear 63 and rotates integrally with the first gear 63 about a common rotational axis, and a load gear 70 engaged with the second gear 64 to decelerate the drive speed; and a load sheave shaft 80 which is coaxial with the load gear 70, extends from the load gear 70 toward one side in the axial direction in parallel to the drive shaft 40, rotates integrally with the load gear 70, and has a load sheave 84. The first gear speed reduction portion G1 is located on the outer side in the radial direction of the outer peripheral portion of the load sheave 84.

Description

Chain block

[0001] The present invention relates to a manually driven chain block.

[0002] A manually driven chain block, as shown in Patent Document 1, for example, has a two-stage reduction mechanism with a gear meshing portion for first-stage reduction and a gear meshing portion for second-stage reduction. In such a two-stage reduction mechanism, the driving force from the hand chain (C2) is transmitted to the hand wheel (80) and the drive shaft (70), and then to the pinion gear (72) on the drive shaft (70) and then to the large-diameter gear (61) (first-stage reduction). The driving force is then transmitted from the small-diameter gear (62) integral with the large-diameter gear (61) to the load gear (31) (second-stage reduction), and then to the load sheave (23) integral with the load gear (31), where the load chain (C1) wound around the load sheave (23) is wound up. This allows the load lifted by the load chain (C1) to be raised or lowered by operating the hand chain (C2).

[0003] Also known is a chain block having a one-stage reduction mechanism, as shown in Patent Document 2. In such a chain block, the driving force is transmitted from a pinion gear (17) provided on the drive shaft (2) to a load gear (first stage reduction), and then to a load sheave (3).

[0004] Japanese Patent Application Laid-Open No. 2014-108840

[0005] However, the chain block disclosed in Patent Document 1 has a problem in that the axial dimension (depth dimension) is large because a two-stage reduction mechanism is arranged inside the gearbox. This large axial dimension requires a lot of space to store a large number of chain blocks, for example, by hanging the upper hooks on the rod-shaped parts.

[0006] Furthermore, the configuration disclosed in Patent Document 2 only has a single-stage reduction mechanism, which makes it possible to reduce the axial dimension. However, this configuration results in a small reduction ratio, which increases the manual force required to lift a load, i.e., the torque required to drive the hand wheel. To enable manual operation with this configuration, the hand wheel must be large, which results in an increase in the overall size of the chain hoist.

[0007] The present invention has been made in consideration of the above circumstances, and has as its object to provide a chain block that can reduce the axial dimension and ensure a sufficient reduction ratio without increasing the size.

[0008] In order to solve the above problems, according to a first aspect of the present invention, there is provided a chain block that includes a hand wheel around which a hand chain is wound, and that can lift and lower a load by pulling the hand chain to rotate the hand wheel, the chain comprising: a drive shaft to which driving force from the hand wheel is transmitted on one axial side; a first gear reduction unit that includes: a pinion gear provided on the other axial side of the drive shaft; and a first gear that meshes with the pinion gear to reduce the drive speed; a second gear that is located on the other axial side of the first gear and that rotates integrally with the first gear on a common rotation axis and has a smaller diameter than the first gear; and a load gear that meshes with the second gear to reduce the drive speed; a load sheave that is located on one axial side of the load gear and is a common axis for the load gear and load sheave and rotates integrally with both; and a load chain that is wound around the load sheave, the first gear reduction unit being located radially outward of the load sheave.

[0009] Another aspect of the present invention is that, in the above-mentioned invention, it is preferable that the invention comprises a first frame and a second frame arranged opposite the first frame on the other axial side, the drive shaft is journaled by the first frame and the second frame, has a first gear accommodating portion constituted by the first frame and the second frame and accommodating the first gear reduction unit, and has a second gear accommodating portion constituted by the second frame and a gear cover attached to the second frame and accommodating the second gear reduction unit.

[0010] In another aspect of the present invention, in the above-mentioned invention, the first gear housing portion and the second gear housing portion are preferably separated by a second frame.

[0011] In addition, another aspect of the present invention is that, in the above-mentioned invention, it is preferable that the common rotating shaft of the first gear and the second gear is supported via a bearing in the first gear accommodating section, and the load sheave shaft is supported via bearings in the first frame and the second frame.

[0012] In addition, another aspect of the present invention is that, in the above-mentioned invention, it is preferable that the common rotating shaft of the first gear and the second gear and the load sheave shaft are each journaled on one side by the first frame and on the other side by the gear cover.

[0013] In another aspect of the present invention, in the above-mentioned invention, the wheel cover that covers the hand wheel is preferably rotatably provided on a support plate that is fixed to the first frame.

[0014] Another aspect of the present invention is that, in the above-mentioned invention, a sheave accommodating space for accommodating a load sheave is provided between the first frame and the second frame abutting the first frame, and a guide member having a pair of guide holes for guiding the load chain entering and exiting the sheave accommodating space and protecting the first and second frames is attached to a portion where the load chain, which is looped around the load sheave and has a lower hook for hanging a load, enters and exits the sheave accommodating space, and the guide member is preferably held in a clamped state by a first guide holding portion provided on the first frame and a second guide holding portion provided on the second frame.

[0015] Another aspect of the present invention is that, in the above-mentioned invention, a stripper is provided between the load sheave and the guide member for separating the load chain wound around the load sheave, and the stripper is preferably held in a clamped state by at least one of a first stripper holding portion provided on the first frame and a second stripper holding portion provided on the second frame.

[0016] According to the present invention, it is possible to provide a chain block that can reduce the axial dimension and ensure a sufficient reduction ratio without increasing the size.

[0017] 1. A perspective view showing the configuration of a chain block according to an embodiment of the present invention. 2. An exploded perspective view showing the configuration of the chain block shown in FIG. 1. 3. A front view showing the configuration of the chain block shown in FIG. 1. 4. A cross-sectional view showing the chain block cut along line 1-1 in FIG. 3. 5. A cross-sectional view showing the chain block cut along line 2-2 in FIG. 3. 6. A cross-sectional view showing the chain block cut along line 3-3 in FIG. 3. 7. A side view mainly showing the arrangement of bearings, reduction gear members, and load gears in the chain block shown in FIG. 1. 8. A cross-sectional view showing a modified example of the chain block according to the present embodiment, cut along the same line as the cross-sectional view shown in FIG. 5. 9. A cross-sectional view showing the configuration near a guide plate through which the load chain passes in the chain block shown in FIG. 1. 10. A cross-sectional view showing another configuration example 1 of the chain block according to the present embodiment, cut along the same line as the cross-sectional view shown in FIG. FIG. 10 is a diagram showing the arrangement of a drive shaft, reduction gear member, load gear, load sheave shaft, and bearings in a chain block having a vertically elongated main body according to a modified example (another configuration example 3) of the present invention.

[0018] A chain block 10 according to an embodiment of the present invention will now be described with reference to the drawings.

[0019] In the following description, the X direction is the axial direction of the drive shaft 40, the X1 side is the side where the wheel cover 14 is located in Figure 2, and the X2 side is the opposite side where the gear cover 17 is located. The Z direction is the vertical direction (hanging direction; hoisting / lowering direction) when the chain block 10 is suspended, the Z1 side is the upper side in the suspended state, and the Z2 side is the lower side in the suspended state. The Y direction is the direction perpendicular to the X and Z directions, the Y1 side is the lower right side in Figure 2, and the Y2 side is the opposite upper left side.

[0020] FIG. 1 is a perspective view showing the configuration of a chain block 10 according to this embodiment. FIG. 2 is an exploded perspective view showing the configuration of the chain block 10 shown in FIG. 1. FIG. 3 is a front view showing the configuration of the chain block 10 shown in FIG. 1. FIG. 4 is a cross-sectional view showing the chain block 10 taken along line 1-1 in FIG. 3. FIG. 5 is a cross-sectional view showing the chain block 10 taken along line 2-2 in FIG. 3. FIG. 6 is a cross-sectional view showing the chain block 10 taken along line 2-2 in FIG. 3. FIG. 7 is a side view showing the arrangement of bearings B1 to B6, reduction gear member 60, and load gear 70 in the chain block 10 shown in FIG. 1.

[0021] (1. Regarding the configuration of the chain block 10) As shown in Figures 1 to 6, the chain block 10 includes a first frame 11, a second frame 12, an upper hook 20, a hand wheel 30, a drive shaft 40, a brake mechanism 50, a load sheave 84, a load chain C2, a first gear reduction section G1, and a second gear reduction section G2.

[0022] (1-1. Regarding the First Frame 11 and the Second Frame 12) The first frame 11 and the second frame 12 are formed of, for example, an aluminum-based metal, for example, by aluminum die-casting or the like. The first frame 11 and the second frame 12 have side plate portions 11f, 12f, which are generally plate-shaped and have irregularities, and are formed with a gearbox GB1 (described later) and a sheave accommodating space SP1 that accommodates the load sheave 84. Furthermore, guide walls 11g, 12g having guide surfaces 11g1, 12g1 that guide the load chain C2, which is looped around the load sheave 84, to the load sheave 84 are formed around the sheave 84. That is, the guide walls 11g, 12g are disposed around the outer periphery of the load sheave 84. The sheave accommodating space SP1 and the gearbox GB1 are separated by the guide walls 11g, 12g.

[0023] The first frame 11 and the second frame 12 support the various components of the chain block 10. The first frame 11, the second frame 12, and a gear cover 17 (described later) are fixed to one another with bolts or the like. A connecting shaft 13 is non-rotatably attached to the upper side (Z1 side) between these frames. Both ends of the connecting shaft 13 are inserted into mounting holes 11h, 12h provided in the side plate portions 11f, 12f of the first frame 11 and the second frame 12. An upper hook 20 for hanging the load chain C2 on, for example, a ceiling is pivotally attached to the connecting shaft 13. The tension of a suspended load applied to the load chain C2 is transmitted to the load sheave shaft 80 via the load sheave 84, and then to the upper hook 20 via the first and second frames 11, 12, which pivotally support the load sheave shaft 80.

[0024] (1-2. Regarding the Wheel Cover 14, etc.) A wheel cover 14 that houses a hand wheel 30 is attached to one side (X1 side) of the first frame 11 in the axial direction (X direction). The hand wheel 30 has a female threaded portion 31, which is a screw hole, at its center. This female threaded portion 31 is screwed into a male threaded portion 41 of a drive shaft 40 (described later). A chain pocket 32 ​​is provided on the outer periphery of the hand wheel 30, between the opposing flange portions 30a, into which metal rings C1a and C1b that constitute the endless hand chain C1 fit. A nut-shaped wheel stopper 34 is provided closer to the tip of the male threaded portion 41 (X1 side) than the hand wheel 30 in the axial direction (X direction). The wheel stopper 34 restricts movement of the hand wheel 30 toward the X1 side.

[0025] 1 to 6, a wheel cover 14 is attached to the first frame 11. The wheel cover 14 has a cover portion 14a, a flange portion 14b, and a pair of chain insertion portions 14c. The cover portion 14a covers the hand wheel 30 to prevent the hand chain C1 from falling off and to protect it from the outside. The cover portion 14a is a cylindrical portion with a bottom.

[0026] The flange portion 14b is a ring-shaped portion that protrudes radially outward from the opening of the cover portion 14a. The flange portion 14b is held in a sandwiched state between the first frame 11 and the support plate 15. The first frame 11 is provided with an annular guide groove 11i that rotatably accommodates the flange portion 14b, and the flange portion 14b is not strongly fixed between the first frame 11 and the support plate 15. Therefore, although movement of the flange portion 14b in the axial direction (X direction) is restricted, it is free to rotate in the circumferential direction. This allows the wheel cover 14 to rotate in accordance with the direction in which the hand chain C1 is pulled, even when the hand chain C1 is pulled in various directions, such as sideways or downward.

[0027] The pair of chain insertion portions 14c are holes for leading out or introducing the hand chain C1 hanging from the hand wheel 30 from the inside to the outside of the wheel cover 14, and are portions located below the wheel cover 14 when the hand chain C1 is normally hanging. In this embodiment, the pair of chain insertion portions 14c have protective members 16 made of, for example, resin. The protective members 16 are members that protect the periphery of the pair of holes formed in the cover portion 14a and the hand chain C1, and also have a soundproofing effect.

[0028] The support plate 15 for rotatably mounting the wheel cover 14 to the first frame 11 includes a ring-shaped portion facing the ring-shaped flange portion 14b of the wheel cover 14, and through holes 15a are formed in portions extending outward from the ring-shaped portion. Screws threaded into screw holes (not shown) in the first frame 11 are inserted into the through holes 15a, and the support plate 15 is mounted to the first frame 11 via the screws. The support plate 15 also includes a cover insertion hole 15b formed in its center, through which the cover portion 14a is inserted. The inner diameter of the cover insertion hole 15b is slightly larger than the outer diameter of the cover portion 14a. However, the inner diameter of the cover insertion hole 15b is smaller than the outer diameter of the flange portion 14b, so the wheel cover 14 is held by the support plate 15 via the flange portion 14b.

[0029] 2 to 5, the drive shaft 40 is a member extending in the X direction from the second frame 12 to the wheel cover 14. The drive shaft 40 passes through the shaft insertion hole 11a of the first frame 11 and protrudes into the wheel cover 14.

[0030] The drive shaft 40 is provided with a male thread portion 41. The male thread portion 41 is a portion into which the female thread portion 31 of the hand wheel 30 and the female thread portion 51a of the brake support member 51 described above are screwed. A step portion 42 is provided at the end of the male thread portion 41 on the X2 side, and the brake support member 51 is engaged with this step portion 42. A stopper receiving portion 43 having a through hole (not shown) and a screw thread 43b is provided at one end of the drive shaft 40, closer to one end (X1 side) in the axial direction (X direction) than the male thread portion 41. The wheel stopper 34 described above is screwed into this stopper receiving portion 43, and the wheel stopper 34 is positioned by attaching a stopper pin (not shown) to the through hole.

[0031] Furthermore, a first bearing attachment portion 44 is provided on the drive shaft 40 on the other side (X2 side) in the axial direction (X direction) of the step portion 42. The first bearing attachment portion 44 is a portion for supporting the drive shaft 40 on the first frame 11 via a bearing B1. To enable such support, a bearing fitting portion 11a1 is provided in the shaft insertion hole 11a that penetrates the side plate portion 11f of the first frame 11, and the bearing fitting portion 11a1 is sized to allow the bearing B1 to be fitted therein.

[0032] A second bearing attachment portion 45 is also provided at the other axial end (X direction) (end on the X2 side) of the drive shaft 40. The second bearing attachment portion 45 is a portion for supporting the drive shaft 40 on the second frame 12 via a bearing B2. To enable this support, a bearing insertion hole 12a is provided in the side plate portion 12f of the second frame 12, and a bearing B2 is fitted into a bearing fitting portion 12a1 of the bearing insertion hole 12a. Note that while the bearing B2 is fitted into the bearing insertion hole 12a from the other axial side (X direction) (X2 side), one axial side (X1 side) of the bearing insertion hole 12a has a smaller diameter than the other portion, preventing the bearing B2 from moving toward the one side (X1 side) of the bearing fitting portion 12a1.

[0033] A pinion gear 46 is provided on the drive shaft 40 between the first bearing attachment portion 44 and the second bearing attachment portion 45. The pinion gear 46 is a part that meshes with a large diameter gear 63 (described later) of the first gear reduction portion G1.

[0034] (1-4. Brake Mechanism 50) A brake mechanism 50 is attached to the drive shaft 40. The brake mechanism 50 mainly comprises the female thread portion 31 of the hand wheel 30, a brake support member 51, brake plates 52 and 53, a ratchet wheel 55, and a pawl member 56. The brake support member 51 has a female thread portion 51a at its center, as well as a flange portion 51b and a hollow boss portion 51c. The female thread portion 51a is threaded onto the male thread portion 41 of the drive shaft 40, and this threading causes the flange portion 51b of the brake support member 51 to engage with the step portion 42 and rotate integrally with the drive shaft 40. The flange portion 51b has a larger diameter than the hollow boss portion 51c and is capable of receiving a brake plate 53, which will be described later. The hollow boss portion 51c is located closer to the hand wheel 30 (X1 side) than the flange portion 51b, and supports the ratchet wheel 55 via a bushing 54, which will be described later.

[0035] The brake plate 52 is located between the central side surface 30b of the hand wheel 30 and the ratchet wheel 55, and the brake plate 53 is located between the ratchet wheel 55 and the flange portion 51b. When the brake plate 52 is pressed against the hand wheel 30, it applies a large frictional force between the hand wheel 30 and the ratchet wheel 55. When the brake plate 53 is pressed against the hand wheel 30, it applies a large frictional force between the flange portion 51b and the ratchet wheel 55, which will be described later. These large frictional forces cause the brake support member 51 to rotate integrally with the ratchet wheel 55.

[0036] 5 and 6, a bushing 54 is attached to the hollow boss portion 51c of the brake support member 51, and a ratchet wheel 55 is provided on the outer periphery of this bushing 54. This allows the ratchet wheel 55 to rotate freely relative to the brake support member 51. The teeth 55a of the ratchet wheel 55 engage with the tip of a pawl member 56 shown in FIG. 2, and this engagement forms a ratchet mechanism that prevents the ratchet wheel 55 from rotating in the reverse direction (rotating in the unwinding direction). The pawl member 56 is rotatably mounted via the pawl shaft 56a, and one end of a biasing spring 56b is attached to the pawl member 56, which applies a biasing force such that the tip of the pawl member 56 always engages with the teeth 55a of the ratchet wheel 55.

[0037] A pair of claw members 56 are provided, and these claw members 56 are arranged 180 degrees apart from each other in the circumferential direction.

[0038] 5 and 7 , a portion of the brake mechanism 50 does not overlap in the axial direction (X direction) with a bearing B5 for supporting the load sheave shaft 80, as described below. In other words, when the chain block 10 is cut in a plane (YZ plane) perpendicular to the axial direction (X direction), a portion of the brake mechanism 50 is not located in the same plane (YZ plane) as the bearing B5 for supporting the load sheave shaft 80. However, as shown in FIG. 8 , the brake mechanism 50 may be configured so that a portion of the brake mechanism 50 overlaps in the axial direction (X direction) with the bearing B5 for supporting the load sheave shaft 80. With the configuration shown in FIG. 8 , it is possible to reduce the dimension of the chain block 10 in the axial direction (X direction).

[0039] (1-5. Reduction Gear Member 60 and First Gear Reduction Section G1) Next, the reduction gear member 60 will be described. As shown in Figures 5 to 7, the reduction gear member 60 has a large-diameter gear 63 that constitutes the first gear reduction section G1 and a small-diameter gear 64 that constitutes the second gear reduction section G2, and has a rotating shaft 60a that has a first bearing attachment portion 61 and a second bearing attachment portion 62. Of these, the first bearing attachment portion 61 is a portion that is located on one end side (X1 side) in the axial direction (X direction) of the reduction gear member 60, and is a portion that is journaled by a bearing recess 11b of the first frame 11. The bearing recess 11b is a concave portion of the first frame 11 that is circular in cross section and is surrounded by a bulge portion 11b1 that bulges out from the side plate portion 11f toward the X1 side. In this embodiment, a bearing B3 such as a needle bearing is fitted into this bearing recess 11b, and the first bearing mounting portion 61 is journaled via this bearing B3.

[0040] The large diameter gear 63 corresponds to the first gear, and the small diameter gear 64 corresponds to the second gear.

[0041] The small-diameter gear 64 is formed on the other axial side of the second bearing attachment portion 62, and the second bearing attachment portion 62 is a portion located between the large-diameter gear 63 and the small-diameter gear 64. The second bearing attachment portion 62 is a portion that is journaled by a journal support portion 12b1 in the insertion hole 12b of the second frame 12 via a bearing B4. The outer diameter of the small-diameter gear 64 is the same as or slightly smaller than that of the second bearing attachment portion 62. The insertion hole 12b is a hole portion that passes through the second frame 12, and the journal support portion 12b1 is a portion in the insertion hole 12b into which a bearing B4, such as a needle bearing, is fitted. The bearing B4 is fitted into the support portion 12b1 from one side (X1 side) in the axial direction (X direction), but the other side (X2 side) in the axial direction (X direction) of the support portion 12b1 is provided with a smaller diameter than the other portions, thereby preventing the bearing B4 from moving to the other side (X2 side).

[0042] The large diameter gear 63 is a gear that meshes with the pinion gear 46 and constitutes the first gear reduction unit G1 together with the pinion gear 46. The large diameter gear 63 is located inside the gear box GB1. The large diameter gear 63 and the pinion gear 46 are set to reduce the speed at a predetermined reduction ratio.

[0043] Furthermore, the small diameter gear 64 is the part of the reduction gear member 60 that protrudes toward the other side (X2 side) in the axial direction (X direction) beyond the side plate portion 12f of the second frame 12 and protrudes into a gear box GB2 (described later). This small diameter gear 64 is the part that meshes with a load gear 70, and this meshing between the small diameter gear 64 and the load gear 70 is set so that the speed is reduced at a predetermined reduction ratio. Note that the gear box GB1 corresponds to the first gear housing portion, and the gear box GB2 corresponds to the second gear housing portion. Note that the gear boxes GB1 and GB2 may be collectively referred to as gear boxes GB.

[0044] (1-6. Regarding the load gear 70, second gear reduction unit G2, and gear box GB2) The load gear 70 is disposed on the other side (X2 side) in the axial direction (X direction) of the side plate portion 12f of the second frame 12. The load gear 70 has a center hole 71, and the center hole 71 and a gear mounting portion 81 of the load sheave shaft 80 (described later) are connected, for example, by a spline connection or other connection structure, so that the two rotate integrally.

[0045] The small diameter gear 64 and the load gear 70 constitute a second gear reduction unit G2. This second gear reduction unit G2 is housed in a gear box GB2 formed by the second frame 12 and a gear cover 17 attached to the second frame 12. The gear cover 17 is a box-shaped part that covers the second gear reduction unit G2 to protect it from the outside. In this embodiment, there is no need to place a bearing in the gear cover 17. The gear box GB2 corresponds to the second gear housing unit.

[0046] (1-7. Regarding the Load Sheave Shaft 80) The load sheave shaft 80 also has a gear mounting portion 81, a first bearing mounting portion 82, a second bearing mounting portion 83, and a load sheave 84. The gear mounting portion 81 is the portion that is coupled to the center hole 71 of the load gear 70, thereby allowing the load gear 70 and the load sheave shaft 80 to rotate integrally.

[0047] The first bearing attachment portion 82 is a portion located on one end side (X1 side) in the axial direction (X direction) of the load sheave shaft 80, and is a portion that is journaled by a bearing recess 11c of the first frame 11. The bearing recess 11c is a circular recess formed in a thick side plate portion 11f near the center of the side plate portion 11f of the first frame 11, and in this embodiment, a bearing B5 is fitted into this bearing recess 11c, and the first bearing attachment portion 82 is journaled via this bearing B5.

[0048] The second bearing attachment portion 83 is located on the other side (X2 side) of the load sheave shaft 80 in the axial direction (X direction) but on one side (X1 side) of the gear attachment portion 81. The second bearing attachment portion 83 is journaled by a journal support portion 12c1 in the insertion hole 12c of the second frame 12. The insertion hole 12c is a hole that penetrates the side plate portion 12f of the second frame 12, and the journal support portion 12c1 is a portion in the insertion hole 12c into which the bearing B6 is fitted. The bearing B6 is fitted from one side (X1 side) of the journal support portion 12c1 in the axial direction (X direction), but the other side (X2 side) of the journal support portion 12c1 in the axial direction (X direction) has a smaller diameter than the other portions, preventing the bearing B6 from moving to the other side (X2 side).

[0049] The load sheave 84 is a portion around which the load chain C2 is looped. The load sheave 84 has a pair of flanges 84a that constitute the load sheave 84, and a chain pocket 84b (see FIG. 4, etc.) that constitutes the load sheave 84 is located between the pair of flanges 84a. The chain pocket 84b is a portion into which the metal rings C2a and C2b of the load chain C2 fit, and has a horizontal pocket (not shown) and a vertical pocket (not shown) that intersects with the horizontal pocket. This allows the metal rings C2a and C2b that constitute the load chain C2, which are connected in different orientations by 90 degrees, to fit into the horizontal pocket and vertical pocket of the chain pocket 84b.

[0050] From the viewpoint of compactness, it is preferable that the load sheave shaft 80 and the load sheave 84 be integrally molded by forging or casting as in this embodiment, but they may also be separate bodies that are joined together by a spline connection or the like.

[0051] (1-8. Regarding gearbox GB1) The gearbox GB1 is formed by a first frame 11 and a second frame 12. Both side surfaces of the gearbox GB1 in the axial direction (X-axis direction) are formed by side plate portions 11f of the first frame 11 and side plate portions 12f of the second frame 12, respectively, and the other side surfaces are formed by gearbox wall surfaces 11k, 12k that bulge out from the side plate portions 11f of the first frame 11 and the side plate portions 12f of the second frame 12 and come into contact with each other.

[0052] Additionally, guide walls 11g, 12g that bulge toward each other and abut against each other are formed from the side plate portion 11f of the first frame 11 and the side plate portion 12f of the second frame 12 so as to surround the periphery of the load sheave accommodating space SP1. The gearbox GB1 and the sheave accommodating space SP1 are partitioned by parts of the guide walls 11g, 12g.

[0053] Furthermore, a side plate portion 11f of the first frame 11 that forms one axial side of the gearbox GB1 is thickened to form a bearing fitting portion 11a1 that holds the bearing B1 that journals the drive shaft 40, and a bearing recess 11b that holds the bearing B3 that journals the first bearing attachment portion 61 of the reduction gear member 60. The bearing recess 11b is a recess with a bottom, but the bearing fitting portion 11a1 is formed in a shaft insertion hole 11a that passes through the side plate portion 11f.

[0054] In addition, the side plate portion 12f of the second frame 12, which forms the other axial side of the gearbox GB1, is formed with a thickened wall to have a bearing insertion hole 12a that holds the bearing B2 that supports the drive shaft 40, and a bearing support portion 12b1 that holds the bearing B4 that supports the second bearing mounting portion 62 of the reduction gear member 60.

[0055] Bearings B1, B3, and B5 are each supported by a journal portion formed on side plate portion 11 f of first frame 11, and bearings B2, B4, and B6 are each supported by a journal portion formed on side plate portion 12 f of second frame 12. Large diameter gear 63 and load sheave 84 are disposed between side plate portion 11 f of first frame 11 and side plate portion 12 f of second frame 12, and large diameter gear 63 is disposed on a radially outward side of load sheave 84.

[0056] In addition, the load gear 70 and the small diameter gear 64 are arranged on the other axial side of the side plate portion 12f of the second frame 12, and the large diameter gear 63, the pinion gear 46 and the load sheave 84 are arranged on one axial side of the side plate portion 12f of the second frame 12.

[0057] (1-9. Guide Plate 90) Figure 9 is a cross-sectional view showing the configuration of the chain block 10 shown in Figure 1 near the guide plate 90 through which the load chain C2 passes. As shown in Figures 2, 6, and 9, the guide plate 90 is attached to the first frame 11 and the second frame 12 below the sheave accommodating space SP1 (Z2 side). The guide plate 90 is a plate-shaped member having a pair of guide holes 90a, 90b. The guide holes 90a, 90b are punched-out portions of the guide plate 90 through which the metal rings C2a, C2b of the load chain C2 are inserted. The guide plate 90 is punched in a substantially cross shape to correspond to the vertical and horizontal orientations of the metal rings C2a, C2b. The guide plate 90 is made of a material that is less likely to deform than the first frame 11 and the second frame 12, which are made of aluminum-based metal, such as an iron-based metal.

[0058] By providing a pair of such guide holes 90a, 90b in the guide plate 90, it is possible to align the direction of the load chain C2 (metal rings C2a, C2b) heading towards the load sheave 84 and the direction of the load chain C2 (metal rings C2a, C2b) being fed out from the load sheave 84. This makes it possible to prevent the metal rings C2a, C2b from colliding with the first frame 11 or the second frame 12 and causing damage to these frames 11 and 12.

[0059] To hold the guide plate 90, the first frame 11 is provided with a holding recess 11d, and the second frame 12 is provided with a holding recess 12d. As shown in Figure 4, the holding recess 11d is provided on the lower side (Z2 side) of the first frame 11 where the load chain C2 enters and exits, and is formed by recessing a portion facing the second frame 12. Similarly, the holding recess 12d is provided on the lower side (Z2 side) of the second frame 12 where the load chain C2 enters and exits, and is formed by recessing a portion facing the first frame 11. The lengths of the holding recess 11d and the holding recess 12d correspond to the length of the guide plate 90.

[0060] With these holding recesses 11d, 12d, when the first frame 11 and the second frame 12 are fixed to each other with bolts or the like, one widthwise end of the guide plate 90 is held by the holding recess 11d, and the other widthwise end of the guide plate 90 is held by the holding recess 12d. Therefore, it is possible to hold the guide plate 90 in a clamped state between the first frame 11 and the second frame 12 without using dedicated screws or the like. The holding recess 11d corresponds to the first guide holding portion, and the holding recess 12d corresponds to the second guide holding portion.

[0061] (1-10. Regarding the stripper 91 and chain guide 92) As shown in Figure 9, a stripper 91 is provided between the load sheave 84 and the guide plate 90. In particular, the load chain C2 on the side that is not under load may get caught in the chain pocket 84b of the load sheave 84 and become wrapped around the load sheave 84, making it difficult for the load chain C2 to be released. In such cases, the stripper 91 is a member that causes the chain links C2b of the load chain C2 to collide with the stripper 91, stripping the load chain C2 from the load sheave 84 and allowing the load chain C2 to flow smoothly through the sheave accommodating space SP1.

[0062] In this embodiment, the stripper 91 is plate-shaped and has a mounting hole 91a formed in its center. Retaining protrusions 11e and 12e fit into the mounting hole 91a. The retaining protrusion 11e is a protruding portion that protrudes from the first frame 11 toward the second frame 12 on the lower side (Z2 side) of the load sheave 84. Similarly, the retaining protrusion 12e is a protruding portion that protrudes from the second frame 12 toward the first frame 11 on the lower side (Z2 side) of the load sheave 84. The retaining protrusions 11e and 12e are abutted against each other while positioned in the mounting hole 91a, thereby enabling the stripper 91 to be held.

[0063] Therefore, when the first frame 11 and the second frame 12 are fixed to each other with bolts or the like, the stripper 91 can be held in a clamped state between the first frame 11 and the second frame 12 without using mounting screws or the like.

[0064] Note that only one of the holding protrusions 11e and 12e may be positioned in the mounting hole 91a. The holding protrusion 11e corresponds to the first stripper holding portion, and the holding protrusion 12e corresponds to the second stripper holding portion.

[0065] A chain guide 92 is provided adjacent to the load sheave 84. The chain guide 92 is a member for guiding the load chain C2, and has the function of preventing the load chain C2 on the side not bearing a load from coming off the load sheave 84 and becoming disordered within the sheave accommodating space SP1, as well as suppressing wear on the guide walls 11g and 12g. The chain guide 92 is preferably provided rotatably, but may also be provided non-rotatably.

[0066] (2. Alternative Configuration Example 1 of the Chain Block 10) As shown in Figures 6 and 7, the bearing B4 that supports the reduction gear member 60 is disposed between the large-diameter gear 63 and the small-diameter gear 64, and the bearing B4 is supported by a journal portion 12b1 formed on the side plate portion 12f of the second frame 12. However, as in Alternative Configuration Example 1 shown in Figures 10 and 11, the bearing B4D may be supported by the gear cover 17D. Note that the components of Alternative Configuration Example 1 that appear in the following description will be explained with the letter "D" next to the reference numerals of the components that appear in Figures 1 to 7 above.

[0067] The reduction gear member 60D has a large-diameter gear 63D, a small-diameter gear 64D, and a rotating shaft 60aD, and the rotating shaft 60aD has a first bearing attachment portion 61D and a second bearing attachment portion 62D at both ends. The first bearing attachment portion 61D is located at one end (X1 end) of the rotating shaft 60aD in the axial direction (X direction) and is supported by a bearing recess 11bD of the first frame 11D via a bearing B3D. The second bearing attachment portion 62D is located at the other end (X2 end) of the rotating shaft 60aD in the axial direction (X direction) and is supported by a bearing recess 17bD of the gear cover 17D via a ball bearing B4D.

[0068] The large-diameter gear 63D is disposed adjacent to the other side (X2 side) of the first bearing mounting portion 61D in the axial direction (X direction), and the small-diameter gear 64D is disposed adjacent to one side (X1 side) of the second bearing mounting portion 62D in the axial direction (X direction). The insertion hole 12bD is a hole portion penetrating the second frame 12D. The rotating shaft 60aD is inserted through the insertion hole 12bD. The large-diameter gear 63D is housed in the gear box GB1D, and the small-diameter gear 64D is housed in the gear box GB2D. It is preferable that the gear box GBD be divided into the gear box GB1D and the gear box GB2D by the side plate portion 12fD of the second frame 12, but the partition can be omitted as appropriate. The gear box GB1D corresponds to the first gear housing portion, and the gear box GB2D corresponds to the second gear housing portion.

[0069] (3. Alternative Configuration Example 2 of Chain Block 10) The configurations shown in Figures 10 and 11 may be further modified as shown in Alternative Configuration Example 2 in Figure 12. Note that, for each part of Alternative Configuration Example 2 that appears in the following description, the reference numerals of the configuration shown in Figure 11 above will be used, but the alphabet "E" will be added next to the reference numerals of parts that have been modified from the configuration shown in Figure 11 in the description.

[0070] In the configuration shown in Fig. 12, the mounting position of the bearing B6 of the load sheave shaft 80 is changed from the configuration shown in Fig. 11. Specifically, the bearing B6E that supports the second bearing mounting portion 83E of the load sheave shaft 80E shown in Fig. 12 is disposed on the other side (X2 side) of the load gear 70E in the axial direction (X direction) rather than on one side (X1 side).

[0071] Therefore, the bearing B6E, together with the bearing B4E, can be supported by the gear cover 17E. That is, the gear cover 17E may be formed of aluminum die-cast, like the first frame 11 and the second frame 12, to provide a bearing recess like the bearing recess 17bD, and the bearing B6E may be fitted and supported in the bearing recess. In this case, the first bearing attachment portion 82E on one axial side (X1 side) of the load sheave shaft 80E is supported by the first frame 11 via the bearing B5E. At the same time, the second bearing attachment portion 83E on the other axial side (X2 side) of the load sheave shaft 80E is supported by the bearing recess 17aE of the gear cover 17E via the bearing B6E. Furthermore, one axial side (X1 side) of the reduction gear member 60E in the X direction (X direction) can also be supported by the ball bearing B3E, and the other axial side (X2 side) can also be supported by the ball bearing B4E.

[0072] Although not shown, when the bearing B6E is journaled by the gear cover 17, it is preferable to adopt a configuration in which the connecting shaft 13 is also journaled by the first frame 11 and the gear cover 17. In these cases, the gear cover 17 is made of a member having the same strength as the first frame 11.

[0073] (4. Operation of the Chain Block 10) In the chain block 10 configured as described above, the hand wheel 30 is rotated in the hoisting direction by pulling the hand chain C1 in the hoisting direction. This rotation in the hoisting direction causes the female thread portion 31 to advance along the male thread portion 41 in a direction that presses against the brake plate 52 of the brake mechanism 50. As a result, the rotational force of the hand wheel 30 is transmitted to the flange portion 51b of the brake support member 51 via the brake plate 52, ratchet wheel 55, and brake plate 53.

[0074] As the hand wheel 30 rotates, the brake support member 51 attempts to rotate relatively to the male threaded portion 41 of the drive shaft 40 so as to be screwed toward the other side (X2 side) in the axial direction (X direction), but the flange portion 51b is restricted from screwing in by the step portion 42 of the drive shaft 40, and no further rotation is possible relative to the drive shaft 40. If the hand wheel 30 continues to rotate in this state, the drive shaft 40 will rotate integrally with the rotation of the hand wheel 30.

[0075] The rotation of the drive shaft 40 is transmitted from the pinion gear 46 of the drive shaft 40 to the large diameter gear 63 of the reduction gear member 60, and further from the small diameter gear 64 of the reduction gear member 60 to the load gear 70. The load sheave shaft 80 then rotates integrally with the load gear 70, thereby winding up the load chain C2 that is wound around the load sheave 84 of the load sheave shaft 80. In this way, the load that is hung on the lower hook 100 that is connected to the lower end of the load chain C2 is lifted.

[0076] On the other hand, when the hand wheel 30 is rotated in the lowering direction by pulling the hand chain C1 in the lowering direction, the rotation in the lowering direction causes the male thread portion 41 to advance in a direction that loosens the female thread portion 31 from pressing against the brake plate 52 of the brake mechanism 50. Then, because the brake is loosened, the load sheave shaft 80, load gear 70, reduction gear member 60, and drive shaft 40 can rotate in the lowering direction, and when the pulling of the hand chain C1 in the lowering direction is stopped, the action of the load weight causes the female thread portion 31 to immediately press against the brake plate 52 of the brake mechanism 50, thereby holding the load.

[0077] Thereafter, the load can be lowered by repeating the above-described release and application of the brake in response to the operation of pulling the hand chain C1 in the winding down direction.

[0078] (5. Effects) The chain block 10 configured as described above includes the drive shaft 40 to which the driving force from the hand wheel 30 is transmitted on one side (X1 side) in the axial direction (X direction), the pinion gear 46 provided on the other side (X2 side) in the axial direction (X direction) of the drive shaft 40, the first gear reduction unit G1 including the large-diameter gear 63 (first gear) meshing with the pinion gear 46 to reduce the driving speed, and the rotation shaft 60a common to the large-diameter gear 63, provided on the other side (X2 side) in the axial direction (X direction) of the large-diameter gear 63 (first gear). the second gear reduction unit G2 including a small-diameter gear 64 (second gear) having a diameter smaller than that of the large-diameter gear 63 and rotating integrally therewith, and a load gear 70 meshing with the small-diameter gear 64 to reduce the drive speed; a load sheave shaft 80 having a load sheave 84 on one side (X1 side) in the axial direction (X direction) of the load gear 70, which is a common shaft for the load gear 70 and the load sheave 84 and rotates integrally with both (load gear 70, load sheave 84); and a load chain C2 wound around the load sheave 84. The first gear reduction unit G1 is located radially outward of the load sheave 84.

[0079] With this configuration, the first gear reduction unit G1 and the load sheave 84 can be positioned so as to overlap in the axial direction (X direction). This makes it possible to reduce the axial (X direction) dimension of the chain block 10 even though the configuration includes a two-stage gear reduction unit, that is, the first gear reduction unit G1 and the second gear reduction unit G2. Therefore, for example, by hanging the upper hook 20 on a rod-shaped portion, it is possible to reduce the space required when storing a large number of chain blocks 10 lined up.

[0080] Furthermore, because the two-stage gear reduction unit is provided, the reduction ratio can be increased compared to a configuration with only a single-stage gear reduction unit, even while reducing the axial dimension (X direction). Even if a sufficient reduction ratio is ensured to reduce the manual force, there is no need to increase the dimensions of the hand wheel 30, which prevents the overall size of the chain block 10 from increasing. The load gear 70 can have approximately the same external dimensions as the hand wheel 30. The embodiment and other configuration examples 1 and 2 of the present invention can have a horizontally elongated chain block body, while other configuration example 3 can have a vertically elongated chain block body. In either case, the overall size of the chain block 10 can be prevented from increasing.

[0081] In the present embodiment, the chain block 10 includes a first frame 11 and a second frame 12 disposed opposite the other side (X2 side) in the axial direction (X direction) of the first frame 11. The drive shaft 40 is journaled by the first frame 11 and the second frame 12, and includes a gear box GB1 (first gear housing) formed by the first frame 11 and the second frame 12 and housing the first gear reduction unit G1, and a gear box GB2 (second gear housing) formed by the second frame 12 and a gear cover 17 attached to the other side (X2 side) in the axial direction of the second frame 12 and housing the second gear reduction unit G2.

[0082] In the chain block 10 configured as described above, the gearbox GB is composed of gearboxes GB1 and GB2. Gearbox GB1 (first gear housing) is comprised of the first frame 11 and the second frame 12 and is located on one side (X1 side) of the second frame 12 in the axial direction (X direction). Of the two bearings that support the load sheave shaft 80, the bearing on one side can be located on the first frame 11, and the bearing on the other side can be located on either the second frame 12 or the gear cover 17. This allows for a smaller axial (X direction) dimension of the chain block 10 compared to a chain block with a two-stage gear reduction unit disclosed in Patent Document 1, in which gearboxes are located only on the other side (X2 side) of the second frame 12 in the axial direction (X direction). Therefore, for example, by hanging the upper hook 20 on a rod-shaped portion, it is possible to reduce the space required for storing multiple chain blocks 10 side by side.

[0083] In this embodiment, the gear box GB1 (first gear housing portion) and the gear box GB2 (second gear housing portion) are separated by a second frame 12.

[0084] In the chain block 10 configured as described above, the pinion gear 46 and the large diameter gear 63, which have a high peripheral speed, can be reliably and satisfactorily lubricated with grease.

[0085] In addition, in this embodiment, the common rotating shaft 60a of the large diameter gear 63 (first gear) and the small diameter gear 64 (second gear) is supported via bearings B3 and B4 (bearings) of the gearbox GB1, and the load sheave shaft 80 is supported by bearings B5 and B6 (bearings) of the first frame 11 and the second frame 12.

[0086] With this configuration, the bearings B1 to B6 can be supported only by the first frame and the second frame, and there is no need to place bearings on the gear cover 17, which improves assembly accuracy and mechanical efficiency.

[0087] In this embodiment, the wheel cover 14 that covers the hand wheel 30 is rotatably mounted on a support plate 15 that is fixed to the first frame 11 .

[0088] When configured in this manner, the wheel cover 14 is rotatable relative to the first frame 11, etc., so even if the direction in which the hand chain C1 is operated is changed, the position of the chain insertion portion 14c provided on the wheel cover 14 can be adjusted to match the direction of operation, making it possible to pull the hand chain C1 well and operate (rotate) the hand wheel 30.

[0089] In addition, in this embodiment, a sheave accommodating space SP1 that accommodates the load sheave 84 is provided between the first frame 11 and the second frame 12 that abuts against the first frame 11, and at the portion where the load chain C2 that is looped around the load sheave 84 and has a lower hook 100 that hangs a load connected to it enters and exits the sheave accommodating space SP1, a guide plate 90 (guide member) that has a pair of guide holes 90a, 90b that guide the load chain C2 as it enters and exits the sheave accommodating space SP1 and protects the first frame 11 and the second frame 12 is attached, and the guide plate 90 (guide member) is held in a clamped state by a holding recess 11d (first guide holding portion) provided in the first frame 11 and a holding recess 12d (second guide holding portion) provided in the second frame 12.

[0090] In this configuration, the guide plate 90 (guide member) having a pair of guide holes 90a, 90b that guide the load chain C2 is held in a clamped state by the holding recess 11d (first guide holding portion) and the holding recess 12d (second guide holding portion). Therefore, there is no need to provide dedicated screws or screw holes for the above-mentioned holding, which eliminates the need to machine screw holes and makes it possible to reduce the number of parts.

[0091] In addition, in this embodiment, a stripper 91 is provided between the load sheave 84 and the guide plate 90 (guide member) for separating the load chain C2 wound around the load sheave 84, and the stripper 91 is held in a clamped state by a holding protrusion 11e (first stripper holding portion) provided on the first frame 11 and a holding protrusion 12e (second stripper holding portion) provided on the second frame 12.

[0092] In this configuration, the stripper 91 is held in a clamped state by the holding protrusion 11 e (first stripper holding portion) and the holding protrusion 12 e (second stripper holding portion). Therefore, there is no need to provide a dedicated screw or screw hole for the above-mentioned holding, which eliminates the need to machine screw holes and makes it possible to reduce the number of parts.

[0093] (6. Modifications) Although the embodiments of the present invention have been described above, the present invention can be modified in various other ways, which will be described below.

[0094] In the above-described embodiment, taking an example of a chain block with a small depth dimension, the connecting shaft 13 that attaches the upper hook 20 to the first frame 11 and the second frame 12 is positioned such that the load line K1 (the line of action acting on the connecting shaft due to the load of the suspended load) extending from the connecting shaft 13 toward the lower hook 100 is approximately perpendicular to the plane H1 that includes the axes of the drive shaft 40 and the load sheave shaft 80. In this case, as shown in Figure 9, when suspended by the upper hook 20, the main body frame (the main body portion consisting of the first frame 11 and the second frame 12) has a horizontally elongated shape.

[0095] However, for a chain block with a small depth dimension, the components are not limited to the above-mentioned arrangement. For example, the position of the connecting shaft 13 may be such that the load line is parallel to the plane including the drive shaft 40 and the load sheave shaft 80. Such a configuration is shown in Figure 13. As shown in Figure 13, when suspended by the upper hook, the outer shape of the main body of the chain block is vertical, and the components are preferably arranged such that the drive shaft 40F and the load sheave shaft 80F are located below the connecting shaft 13F in this order.

[0096] The configuration shown in Figure 13 also shows the reduction gear member 60F and the load gear 70F. Additionally, bearings B1F and B2F that support the drive shaft 40F in the axial direction (X direction), bearings B3F and B4F that support the reduction gear member 60F, and bearings B5F and B6F that support the load sheave shaft 80F are also shown. The bearings B1F, B3F, and B5F are supported by the first frame 11 (not shown in Figure 13), while the bearings B2F, B4F, and B6F are supported by the second frame 12 (not shown in Figure 13). The connecting shaft 13F is supported at both ends by the first frame 11 (not shown in Figure 13) and the second frame 12 (not shown in Figure 13). Furthermore, even in the case of a vertically long chain block, the arrangement of the bearings B2F, B4F, and B6F is not limited to the arrangement shown in Figure 13, and they may be arranged on the second frame 12 and the gear cover 17, as in the other embodiments.

[0097] Furthermore, the connecting shaft 13 can be attached to the frame in positions other than those described above. However, if it is desired to minimize the vertical dimension, a configuration in which the connecting shaft 13 is arranged in a position where the load line is perpendicular to the plane including the drive shaft 40 and the load sheave shaft 80 (the configuration shown in Figures 1 to 12) is preferred, and if it is desired to minimize the horizontal width, a configuration in which the connecting shaft 13 is arranged in a position where the load line is parallel to the plane including the drive shaft 40 and the load sheave shaft 80 (the configuration shown in Figure 13) is preferred.

[0098] 12 can be understood as follows: The common rotating shaft 60a of the large diameter gear 63 (first gear) and the small diameter gear 64 (second gear) and the load sheave shaft 80E are each supported on one side (X1 side) by bearings B3E and B5E of the first frame 11, and on the other side (X2 side) by bearings B4E and B6E of the gear cover.

[0099] By adopting such a configuration, it is possible to arrange ball bearings with excellent durability and mechanical efficiency for bearings B3E to B6E as well as bearings B1 and B2 without increasing the size of the chain hoist, thereby improving operability and reducing fatigue of the operator.

[0100] DESCRIPTION OF SYMBOLS 10... Chain block, 11, 11D... First frame, 11a... Shaft insertion hole, 11a1... Bearing fitting portion, 11b, 11bD... Bearing recess, 11b1... Bulging portion, 11c... Bearing recess, 11d... Retaining recess, 11d... Retaining recess (corresponding to first guide retaining portion), 11e... Retaining protrusion (corresponding to first stripper retaining portion), 11f, 12f... Side plate portion, 11g, 12g... Guide wall, 11g1, 12g1... Guide surface, 11h, 12h... Mounting hole, 11i... Annular guide groove, 11k, 12k... Gear box wall portion, 12, 12D ...second frame, 12a...bearing insertion hole, 12a1...bearing fitting portion, 12b, 12bD...insertion hole, 12b1...bearing support portion, 12c...insertion hole, 12c1...bearing support portion, 12d...holding recess (corresponding to second guide holding portion), 12e...holding protrusion (corresponding to second stripper holding portion), 12f, 12fD...side plate portion, 13, 13F...connecting shaft, 14...wheel cover, 14a...cover portion, 14b...flange portion, 14c...chain insertion portion, 15...support plate, 15a...through hole, 15b...cover insertion hole, 16...protective member, 17...gear cover Bar, 17, 17D... gear cover, 17aE... bearing recess, 17bD... bearing recess, 20... upper hook, 30... hand wheel, 30a... flange portion, 31... female thread portion, 32... chain pocket, 34... wheel stopper, 40, 40F... drive shaft, 41... male thread portion, 42... step portion, 43... stopper receiving portion, 43b... thread, 44... bearing mounting portion, 45... bearing mounting portion, 46... pinion gear, 50... brake mechanism, 51... brake support member, 51a... female thread portion, 51b... flange portion, 51c... hollow boss portion, 52, 53...Brake plate, 54...Bush, 55...Ratchet wheel, 55a...Claw portion, 56...Claw member, 56a...Claw shaft, 56b...Biasing spring, 60, 60D, 60F...Reduction gear member, 60a, 60aD...Rotating shaft, 61, 61D...First bearing mounting portion, 62, 62D...Second bearing mounting portion, 63, 63D...Large diameter gear (corresponding to first gear), 64, 64D...Small diameter gear (corresponding to second gear), 70, 70F...Load gear, 71...Center hole, 80, 80E, 80F...Load sheave shaft, 81...Gear mounting portion, 82, 82E...First bearing mounting portion, 83,83E... Second bearing mounting portion, 84... Load sheave, 84a... Flange portion, 84b... Chain pocket, 90... Guide plate (corresponding to guide member), 90a... Insertion slit, 91... Stripper, 91a... Mounting hole, 92... Chain guide, 100... Lower hook, B1, B1F bearing, B2, B2F... Bearing, B3, B3D, B3F... Bearing, B4, B4D... Bearing (corresponding to bearing), B5, B5E, B5F... Bearing, B6, B6E... Bearing, C1... Hand chain, C1a, C1b... Metal ring, C2... Load chain, C2a, C2b... Metal ring, GB1, GB1D... Gear box (corresponding to first gear box), GB2, GB2D... Gear box (corresponding to second gear box), SP1... Sheave accommodating space,

Claims

1. A chain block equipped with a hand wheel around which a hand chain is looped, and which is capable of lifting or lowering a load by pulling the hand chain to rotate the hand wheel, comprising: a drive shaft to which driving force from the hand wheel is transmitted on one axial side; a first gear reduction unit comprising a pinion gear provided on the other axial side of the drive shaft and a first gear that meshes with the pinion gear to reduce the driving speed; a second gear reduction unit located on the other axial side of the first gear and comprising a second gear that rotates integrally with the first gear on a common rotating shaft and has a smaller diameter than the first gear, and a load gear that meshes with the second gear to reduce the driving speed; a load sheave shaft that has a load sheave on one axial side of the load gear and is a common shaft for the load gear and the load sheave that rotates integrally with both of them; and a load chain looped around the load sheave, wherein the first gear reduction unit is located radially outward of the load sheave.

2. A chain block according to claim 1, comprising a first frame and a second frame arranged opposite the first frame on the other side in the axial direction, the drive shaft being journalled by the first frame and the second frame, a first gear accommodating section formed by the first frame and the second frame and accommodating the first gear reduction section, and a second gear accommodating section formed by the second frame and a gear cover attached to the second frame and accommodating the second gear reduction section.

3. A chain block according to claim 2, wherein the first gear housing and the second gear housing are separated by the second frame.

4. A chain block according to claim 2, wherein the common rotating shaft of the first gear and the second gear is supported via a bearing in the first gear accommodating section, and the load sheave shaft is supported via bearings in the first frame and the second frame.

5. A chain block according to claim 2, wherein the rotation shaft common to the first gear and the second gear and the load sheave shaft are each supported on one side by the first frame and on the other side by the gear cover.

6. A chain block according to claim 2, wherein the wheel cover that covers the hand wheel is rotatably mounted on a support plate fixed to the first frame.

7. A chain block as claimed in claim 2, characterized in that a sheave accommodating space for accommodating the load sheave is provided between the first frame and the second frame abutting against the first frame, and at a portion where the load chain, which is looped around the load sheave and has a lower hook for hanging a load connected thereto, enters and leaves the sheave accommodating space, a guide member is attached which has a pair of guide holes for guiding the load chain as it enters and leaves the sheave accommodating space and which protects the first frame and the second frame, and the guide member is held in a clamped state by a first guide holding part provided on the first frame and a second guide holding part provided on the second frame.

8. A chain block according to claim 7, characterized in that a stripper is provided between the load sheave and the guide member for separating the load chain wound around the load sheave, and the stripper is held in a clamped state by at least one of a first stripper holding portion provided on the first frame and a second stripper holding portion provided on the second frame.

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