Manual chain block

Abstract

Provided is a manual chain block capable of suppressing size increase while increasing the strength of a wheel cover.　A manual chain block 10 comprises: a hand wheel 7 around which a hand chain 6, operated by a worker through a hand pulling action, is wound; a frame 1 which pivotally supports a drive shaft 71 of the hand wheel 7 and which is provided adjacent to the hand wheel 7; and a wheel cover 8 which has a cylindrical portion 8e that covers the outer periphery of the hand wheel 7 and that is formed in a cylindrical shape, one end 8a of the cylindrical portion 8e being closed and the other end 8b thereof comprising an opening end 8c that is rotatably attached to a frame 11. The frame 11 has an annular support ring 11e which protrudes from a front side surface 11a on the wheel cover 8 side and has a diameter smaller than the diameter of the opening end 8c. The wheel cover 8 is attached to the frame 11 in a state in which the opening end 8c is disposed on the outer periphery of the support ring 11e.

Description

Manual Chain Hoist

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

[0002] A manual chain hoist is equipped with a wheel cover that covers a hand wheel that engages with a manually operated hand chain. Some wheel covers have a through hole that guides the hand chain to the hand wheel, and are attached to a frame so that they can rotate freely in the direction of operation of the hand chain (see, for example, Patent Document 1).

[0003] The wheel cover disclosed in Patent Document 1 is disposed on the outermost side of one side of the manual chain hoist, and therefore, when the manual chain hoist falls, the wheel cover is often subjected to impact.

[0004] Special Publication No. 2003-516916

[0005] Incidentally, Patent Document 1 also discloses that the edge of a cylindrical hood corresponding to a wheel cover that contacts a side plate is curled into a U-shape to increase the strength of the wheel cover itself compared to bending. Because the wheel cover has a cylindrical shape with a bottom, when the cylindrical portion is pressed from the outside, the opening side is more likely to deform into an elliptical shape than the bottom side.

[0006] However, with the technology described in Patent Document 1, simply increasing the strength through curling is not sufficient to prevent deformation of the wheel cover due to impacts applied to the wheel cover, and measures such as increasing the thickness of the wheel cover are required, which increases the weight of the manual chain hoist accordingly.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manual chain block that can be made lighter and smaller while increasing the strength of the wheel cover.

[0008] A manual chain block according to one aspect of the present invention comprises a hand wheel around which a hand chain manually operated by an operator is looped; a frame disposed adjacent to the hand wheel and supporting the drive shaft of the hand wheel; a cylindrical portion formed in a cylindrical shape that covers the outer periphery of the hand wheel; and a wheel cover having one closed end and the other open end, the open end of which is rotatably attached to the frame, the frame having an annular support ring that protrudes from the front surface on the wheel cover side and has a smaller diameter than the open end, and the wheel cover is attached to the frame with the open end positioned on the outer periphery of the support ring.

[0009] According to the present invention, it is possible to provide a manual chain block that can be made lighter and smaller while increasing the strength of the wheel cover.

[0010] Fig. 1 is a perspective view showing the overall configuration of a manual chain block according to this embodiment. Fig. 2 is a cross-sectional view showing a cross section cut along a vertical plane Z parallel to the drive shaft of the manual chain block of Fig. 1. Fig. 3 is a perspective view showing a first frame alone of the manual chain block according to this embodiment, viewed from the same direction as Fig. 1. Fig. 4 is a partially enlarged cross-sectional view showing an enlarged view of range A in Fig. 2. Fig. 5 is a partially enlarged cross-sectional view showing a modified example of the opening end of the wheel cover according to this embodiment, where A shows a bending process, B shows an inward curling process, and C shows an outward curling process in which the end is directed toward the expanded annular portion.

[0011] Hereinafter, a manual chain block 10 according to this embodiment will be described with reference to the drawings.

[0012] (Manual Chain Block) Fig. 1 is a perspective view showing the overall configuration of a manual chain block 10 according to this embodiment. Fig. 2 is a cross-sectional view showing a cross section cut along a vertical plane Z parallel to the drive shaft of the manual chain block of Fig. 1.

[0013] The manual chain block 10 includes a chain block body 1, an upper hook 2, a load sheave 3, a load chain 4, a lower hook 5, a hand chain 6, a hand wheel 7, and a wheel cover 8.

[0014] The chain block body 1 has a first frame 11, a second frame 12, and a third frame 13, and is formed by stacking the frames 11, 12, and 13 in this order and fastening them with bolts. The first frame 11, the second frame 12, and the third frame 13 are each formed by aluminum die-casting.

[0015] The upper hook 2 is located at the top of the chain block body 1 and suspends the manual chain block 10 by hanging it from a beam or the like of a structure (not shown). The upper hook 2 has a top hinge 2a at its bottom that is rotatable around a vertical axis, and a hook hole 2b is formed in the top hinge 2a, with a hanging shaft 21 inserted through the hook hole 2b. The hanging shaft 21 is connected to the chain block body 1 by inserting it from the first frame 11 side into an insertion hole 1a that extends through the first frame 11 and second frame 12 of the chain block body 1 and over to the middle of the third frame 13. After the hanging shaft 21 is inserted through the hook hole 2b and the insertion hole 1a, it is positioned and prevented from coming off by a retaining plate 81 (described later) that rotatably holds the wheel cover 8 to the first frame 11.

[0016] The load sheave 3 is rotatably sandwiched between the first frame 11 and the second frame 12, and the load chain 4 is wound around it. The load chain 4 has a lower hook 5 connected to its lower end, and supports the weight of a load suspended from the lower hook 5. The load sheave 3 lifts or lowers the load chain 4 depending on its direction of rotation, thereby raising or lowering the load.

[0017] The hand wheel 7 rotates together with the drive shaft 71 journaled on the first frame 11, and a part of the hand wheel 7 is wound around the endless hand chain 6. The hand chain 6 transmits the operating force exerted by the operator's hand to the hand wheel 7, causing it to rotate.

[0018] The rotation of the hand wheel 7 caused by the operator's manual pulling is reduced in speed by a reduction gear mechanism 72 from the drive shaft 71 and transmitted to the load sheave 3. The load sheave 3 rotates in response to the rotation of the hand wheel 7, and the load chain 4 is wound up or down, raising or lowering the suspended load. A mechanical brake 73 that holds the suspended load is disposed on the drive shaft 71.

[0019] The wheel cover 8 covers the outer periphery of the hand wheel 7. The wheel cover 8 has a cylindrical shape with one end 8a closed and the other end 8b open, and the open end 8c as the other end 8b is attached to the first frame 11 with a predetermined gap between the inner periphery of the cylindrical portion 8e and the outer periphery of the hand wheel 7.

[0020] The wheel cover 8 has two through holes 8d in the cylindrical portion 8e for passing the endless hand chain 6 wound around the hand wheel 7. An operator may manually pull the hand chain 6 from any direction around the entire 360° circumference of the hand wheel 7. The wheel cover 8 can rotate 360° in the circumferential direction so that the through holes 8d follow the direction in which the operator pulls the hand chain 6.

[0021] The wheel cover 8 has a generally triangular protrusion 8a1 extending from the closed surface at one closed end 8a, and a circular recess 8a2 at the center of the protrusion 8a1. The wheel cover 8 also has protrusions 8e1 on the cylindrical portion 8e that extend from the vertices of the generally triangular shape of the protrusion 8a1 to the other end 8b. The wheel cover 8 can have improved strength, even with a thin plate structure, compared to a case where the wheel cover 8 is composed of a cylindrical portion and a closed portion with no irregularities.

[0022] The other end 8b of the cylindrical portion 8e has an expanded annular portion 8e2 expanded to the same diameter as the protrusion 8e1, and an opening end 8c is formed in the expanded annular portion 8e2. The opening end 8c has a larger diameter than the expanded annular portion 8e2 and is provided at the other end 8b of the wheel cover 8 in a flange-like shape.

[0023] (Annular Rib) The first frame 11 to which the open end 8c of the wheel cover 8 is attached will now be described with reference to Fig. 3. Fig. 3 is a perspective view showing the first frame 11 alone of the manual chain block 10 according to this embodiment, viewed from the same direction as Fig. 1.

[0024] The first frame 11 is a generally plate-shaped member having an uneven surface, with a front side 11a on which the wheel cover 8 is attached and a back side 11b on which the second frame 12 is stacked. The first frame 11 has an annular rib 11e protruding from the front side 11a. The first frame 11 also has a concave surface 11c recessed inward from the front side 11a toward the back side 11b, and the concave surface 11c is divided by the annular rib 11e into an outer concave surface 11c1 and an inner concave surface 11c2. The first frame 11 also has an outer peripheral wall 11d surrounding the outer concave surface 11c1. In the embodiment shown in FIGS. 1 to 4, the outer concave surface 11c1 is recessed toward the back side relative to the outer peripheral wall 11d, but the outer concave surface 11c1 may also protrude toward the front side 11a to a degree not exceeding the annular rib 11e. In other words, the outer concave surface 11c1 does not necessarily need to be recessed relative to the outer peripheral wall 11d. The outer peripheral wall 11d is also a mounting portion for the pressing plate 81.

[0025] The outer recessed surface 11c1 on the outer periphery of the annular rib 11e has a plurality of reinforcing ribs 11f of the first frame 11 extending radially from the annular rib 11e, but the height of the reinforcing ribs 11f is all lower than the height of the annular rib 11e. As a result, a groove 11g of a predetermined depth is formed between the annular rib 11e and the outer peripheral wall 11d along the entire circumference, extending from the front surface 11a toward the back surface 11b. The inner recessed surface 11c2 on the inner periphery of the annular rib 11e is provided with a mechanical brake 73, and a pawl shaft hole 11c3 is provided for mounting the pawl shaft 72b of the mechanical brake 73. A bearing hole 11c4 for supporting the drive shaft 71 is provided in the center of the inner recessed surface 11c2.

[0026] The wheel cover 8 is attached to the front side surface 11a of the first frame 11 formed in this manner. The attachment of the wheel cover 8 will be described with reference to Figs.

[0027] The opening end 8c of the wheel cover 8 is curled around the entire circumference, and has a certain flange-like width in the radial direction. The curling is performed so that the opening end 8c of the wheel cover 8 is curled outward from the wheel cover 8, and the tip is folded back to face the one end 8a at a distance from the outer periphery of the expanded annular portion 8e2.

[0028] Furthermore, with the drive shaft 71 and hand wheel 7 attached to the chain block body 1, the open end 8c of the wheel cover 8 is inserted into the groove 11g in the outer concave surface 11c1 on the outer periphery of the annular rib 11e of the first frame 11. Therefore, even if the open end 8c of the wheel cover 8 extends from one end 8a toward the other end 8b by the curling process, the extended portion is inserted into the outer periphery of the annular rib 11e of the first frame 11, so when the wheel cover 8 is attached to the first frame 11, the dimension of the wheel cover 8 extending axially outward from the first frame 11 does not increase.

[0029] 2, the opening end 8c of the wheel cover 8 is accommodated in a groove 11g on the outer periphery of the annular rib 11e, and a gap is formed so that the inner periphery of the opening end 8c is in sliding contact with the outer periphery of the annular rib 11e. This allows the wheel cover 8 to rotate 360° depending on the circumferential position of the through-hole 8d through which the hand chain 6 passes.

[0030] The manual chain hoist 10 also has a ring-shaped presser plate 81 with a circular hole 81a on the inside. The hole 81a of the presser plate 81 has a diameter smaller than the outermost portion of the curled portion, which is the maximum outer diameter of the open end 8c of the wheel cover 8, and slightly larger than the outer diameter of the expanded annular portion 8e2 of the cylindrical portion 8e. The presser plate 81 has a shape that follows the outer periphery of the outer wall 11d of the first frame 11 so that it does not protrude outside the first frame 11 when attached to the first frame 11. The hole 81a of the presser plate 81 has a cylindrical hole flange portion formed by hole flange processing (burring processing) or the like so that it can slide on the outer periphery of the expanded annular portion 8e2.

[0031] The retaining plate 81 is bolted to the first frame 11 with the open end 8c of the wheel cover 8 inserted into the groove 11g on the outer periphery of the annular rib 11e (FIG. 1). This allows the wheel cover 8 to be positioned at a predetermined position on the first frame 11 while allowing the wheel cover 8 to rotate, thereby enabling the hand chain 6 to be properly guided by the hand wheel 7. Furthermore, by bolting the retaining plate 81 to the first frame 11, the hanging shaft 21 connecting the upper hook 2 to the chain block body 1 is prevented from coming out of the hook hole 2b by contacting the retaining plate 81. In other words, the retaining plate 81 serves both to prevent the hanging shaft 21 of the upper hook 2 from slipping out and to prevent the wheel cover 8 from slipping out. Therefore, the retaining plate 81 facilitates the attachment and detachment of the hanging shaft 21 without disassembling the first frame 11, second frame 12, and third frame 13, and contributes to the miniaturization of the chain block body 1 while ensuring convenience.

[0032] Next, the dimensional relationship between the annular rib 11e, the opening end 8c of the wheel cover 8, and the hole 81a of the pressing plate 81 will be described with reference to Fig. 4. Fig. 4 is a partially enlarged cross-sectional view showing an area A in Fig. 2 in an enlarged scale.

[0033] As described above, when the wheel cover 8 is attached to the first frame 11, the dimensions of each component are set so that the radial gap dimension C1 between the opening end 8c and the annular rib 11e within the first frame 11 is smaller than the radial gap dimension C2 between the opening end 8c and the hole 81a.

[0034] As a result, when an external impact is applied to the wheel cover 8, the open end 8c on the side of the wheel cover 8 that receives the impact is first pressed against the annular rib 11e of the first frame 11, preventing deformation of the open end 8c, which has lower rigidity than the one end 8a of the wheel cover 8, and maintaining its cylindrical shape. Therefore, there is no need to make the wheel cover thicker to increase its strength, making it possible to reduce its weight. Furthermore, since there is no need to provide a reinforcing member to prevent the open end 8c from deforming into an oval shape, the radial dimension of the entire hand wheel 7 portion of the manual chain hoist 10 can be reduced.

[0035] In the above embodiment, the first frame 11, the second frame 12, and the third frame 13 are formed by aluminum die-casting, but they may be formed by other materials and forming methods. In this case, it is preferable that, as in the first frame 11, a recessed space is formed inward from the front surface 11 a to accommodate various components, and that the manual chain hoist 10 has sufficient strength.

[0036] The annular rib 11e is integrally molded with the first frame 11 by aluminum die-casting, but it may also be molded separately and then assembled to the first frame. In that case, it is preferable that the annular rib 11e be molded integrally with the outer peripheral wall 11d.

[0037] In the above embodiment, the opening end 8c of the wheel cover 8 is curled, but it may be folded as long as the strength is maintained within an allowable range (see A in FIG. 5). Also, although the opening end 8c of the wheel cover 8 is curled outward, it may be curled inward (see B in FIG. 5). Furthermore, as for the outward curling, the curled end may be formed so as to face the expanded annular portion 8e2 (see C in FIG. 5).

[0038] In the above embodiment, the annular rib 11e has been described as having a continuous annular shape in the circumferential direction, but it may be partially missing in the circumferential direction. In this case, it is sufficient that the opening end 8c of the other end 8b of the wheel cover 8 is rotatable and has an overall annular shape to the extent that it can absorb impacts.

[0039] In the above embodiment, the opening end 8c is rotatably accommodated in the groove 11g, but the groove 11g is not necessarily required, and an annular rib may be formed to protrude from the mounting surface of the pressing plate toward one end. In this case, the pressing plate is shaped to restrict the opening end from moving toward the one end with the pressing plate, and to provide an accommodation space for the opening end so that the wheel cover can rotate.

[0040] [Supplementary Explanation of the Embodiments] The above-described embodiments each show a preferred specific example of the present invention. The numerical values, components, arrangement positions of the components, order of connection, etc. shown in the above-described embodiments are merely examples and are not intended to limit the present invention. Furthermore, the drawings are not necessarily strict illustrations.

[0041] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0042] [Additional Notes] The contents of the above-described embodiments can be understood, for example, as follows.

[0043] (1) Rib (support ring) The manual chain block 10 comprises a hand wheel 7 around which a hand chain 6 that is manually pulled by an operator is wound, a first frame 11 that is provided adjacent to the hand wheel 7 and supports the drive shaft 71 of the hand wheel 7, a cylindrical portion 8e that is formed in a cylindrical shape and covers the outer periphery of the hand wheel 7, and a wheel cover 8 that has one end 8a of the cylindrical portion 8e closed and the other end 8b having an open end 8c, the open end 8c being rotatably attached to the first frame 11, the first frame 11 having an annular rib 11e that protrudes from the front surface 11a on the wheel cover 8 side and has a smaller diameter than the open end 8c, and the wheel cover 8 is attached to the first frame 11 with the open end 8c positioned on the outer periphery of the annular rib 11e.

[0044] As a result, the annular rib 11e is disposed around the entire inside of the opening end 8c of the wheel cover 8, so that even if an impact is applied to the wheel cover 8 from the outer circumferential direction, the opening end 8c is received by the annular rib 11e on the side where the impact is applied, preventing deformation of the wheel cover 8. In particular, compared to a case where the impact applied to the wheel cover 8 is received by the hole 81a of the presser plate 81 on the outer circumferential side opposite the location of the impact on the opening end 8c across the drive shaft 71, this embodiment does not require a reinforcing member to be provided on the outer circumferential side of the wheel cover 8 to prevent the opening end 8c from deforming into an elliptical shape due to the impact. Therefore, the radial dimension of the entire hand wheel 7 portion of the manual chain block 10 can be reduced.

[0045] Therefore, in this embodiment, the opening end 8c at the other end 8b of the wheel cover 8 is prevented from deforming into an ellipse, which would prevent the wheel cover 8 itself from rotating or interfere with the internal hand wheel 7 or hand chain 6, thereby reducing workability, thereby preventing a decrease in workability and malfunction of the manual chain block 10.

[0046] (2) Flange-shaped Opening End The opening end 8c of the wheel cover 8 is formed in a flange shape at the other end 8b of the cylindrical portion 8e, and the first frame 11 may further include a retaining plate 81 that is fixed to a position surrounding the annular rib 11e on the front side surface 11a and rotatably positions the flange-shaped opening end 8c on the outer periphery of the annular rib 11e to prevent it from coming off.

[0047] This allows the opening end 8c of the wheel cover 8 to be formed in a flange shape, thereby improving the radial strength of the opening end 8c. Also, simply by fixing the pressing plate 81 to the first frame 11, the opening end 8c of the wheel cover 8 can be attached to the outer periphery of the annular rib 11e, which makes it easy to attach the wheel cover 8 and prevents the opening end 8c of the wheel cover 8 from slipping off the outer periphery of the annular rib 11e.

[0048] (3) Gap Size The gap between the inner periphery of the open end 8c and the outer periphery of the annular rib 11e may be smaller than the gap between the outer periphery of the cylindrical portion 8e and the retainer plate 81.

[0049] As a result, the gap dimension C1 between the inner periphery of the opening end 8c and the outer periphery of the annular rib 11e can be made smaller than the gap dimension C2 between the outer periphery of the expanded annular portion 8e2 of the opening end 8c and the hole 81a of the pressing plate 81. It is preferable that the gap dimension C1 be smaller than the gap dimension C2, but they may be approximately the same.

[0050] As a result, when an external impact is applied to the wheel cover 8, the opening end 8c of the wheel cover 8 first collides with and is received by the annular rib 11e, and therefore the opening end 8c of the wheel cover 8 can be prevented from being deformed into an ellipse, compared to when the impact is received by the pressing plate 81 without the annular rib 11e.

[0051] Furthermore, since the retaining plate 81 is fixed to the first frame 11 with bolts, it is possible to prevent the wheel cover 8, when subjected to an impact, from directly colliding with the retaining plate 81 without the annular rib 11e, which would apply a large shear force to the bolt and cause the bolt to break or loosen. In other words, the bolt can be made smaller, preventing the device from becoming larger.

[0052] (4) Curling Process The opening end 8c may be subjected to curling process.

[0053] This increases the rigidity of the opening end 8c of the wheel cover 8, improving the rigidity of the entire wheel cover 8 and suppressing deformation of the wheel cover 8 when an impact is applied. The opening end 8c may be formed by any processing method, such as curling or hemming, as long as it forms a flange shape on the cylindrical portion 8e. Furthermore, since the other end 8b of the wheel cover 8 is formed with the expanded annular portion 8e2, the rigidity of the other end 8b of the wheel cover 8 can be further increased by combining this with curling.

[0054] (5) The device further includes a hanging shaft 21 accommodated in the insertion hole 1a of the first frame 11 of the pressure plate, and an upper hook 2 attached to the structure and connected to the first frame 11 via the hanging shaft 21 to suspend the first frame 11, and the hanging shaft 21 may be fixed in place in the insertion hole 1a by the pressure plate 81 to prevent it from coming loose.

[0055] As a result, the lifting shaft 21 that connects the upper hook 2 to the first frame 11 is fixed and prevented from coming off by the retaining plate 81, so the retaining plate 81 can be used both to prevent the lifting shaft 21 of the upper hook 2 from coming off and to attach the wheel cover 8. Therefore, the retaining plate 81 can easily attach and detach the lifting shaft 21 to and from the first frame 11, thereby making it possible to reduce the size of the entire manual chain hoist 10.

[0056] 2 Upper hook 6 Hand chain 7 Hand wheel 8 Wheel cover 8a One end 8b Other end 8c Open end 8e Cylindrical portion 10 Manual chain block 11 First frame (frame) 11a Front surface 11c Concave surface 11e Annular rib (support ring) 11g Groove 21 Lifting shaft 71 Drive shaft 81 Presser plate C1, C2 Gap dimension

Claims

1. A manual chain hoist comprising: a hand wheel around which a hand chain that is manually operated by an operator is looped; a frame that supports the drive shaft of the hand wheel and is provided adjacent to the hand wheel; a cylindrical portion that is formed in a cylindrical shape and covers the outer periphery of the hand wheel; and a wheel cover that has one end of the cylindrical portion closed and the other end open, the open end being rotatably attached to the frame; wherein the frame has an annular support ring that protrudes from the front surface on the wheel cover side and has a smaller diameter than the open end, and the wheel cover is attached to the frame with the open end positioned on the outer periphery of the support ring.

2. A manual chain block according to claim 1, wherein the opening end of the wheel cover is formed in a flange shape at the other end of the cylindrical portion, and the frame further comprises a presser plate fixed to the front side in a position surrounding the support ring, the flange-shaped opening end of which is rotatably attached on the outer periphery of the support ring.

3. A manual chain block according to claim 2, wherein the gap between the inner periphery of the open end and the outer periphery of the support ring is smaller than the gap between the outer periphery of the cylindrical portion and the presser plate.

4. A manual chain block according to claim 1, wherein the open end is subjected to curling processing.

5. A manual chain block as claimed in claim 2, further comprising: a hanging shaft accommodated in an insertion hole of the frame; and an upper hook attached to a structure and connected to the frame via the hanging shaft to suspend the frame, wherein the hanging shaft is fixed in the insertion hole by the retaining plate to prevent it from coming loose.

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