CA2136558C - Manual chain block - Google Patents
Manual chain blockInfo
- Publication number
- CA2136558C CA2136558C CA002136558A CA2136558A CA2136558C CA 2136558 C CA2136558 C CA 2136558C CA 002136558 A CA002136558 A CA 002136558A CA 2136558 A CA2136558 A CA 2136558A CA 2136558 C CA2136558 C CA 2136558C
- Authority
- CA
- Canada
- Prior art keywords
- friction
- handwheel
- wheel
- plate
- boss
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
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- JOCJYBPHESYFOK-UHFFFAOYSA-K nickel(3+);phosphate Chemical compound [Ni+3].[O-]P([O-])([O-])=O JOCJYBPHESYFOK-UHFFFAOYSA-K 0.000 claims description 3
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- 239000011651 chromium Substances 0.000 claims description 2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
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- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
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- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241000448280 Elates Species 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
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- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
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- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- KYNKUCOQLYEJPH-UHFFFAOYSA-N [K][Ti] Chemical compound [K][Ti] KYNKUCOQLYEJPH-UHFFFAOYSA-N 0.000 description 1
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- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 235000015250 liver sausages Nutrition 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
- B66D3/00—Portable or mobile lifting or hauling appliances
- B66D3/12—Chain or like hand-operated tackles with or without power transmission gearing between operating member and lifting rope, chain or cable
- B66D3/16—Chain or like hand-operated tackles with or without power transmission gearing between operating member and lifting rope, chain or cable operated by an endless chain passing over a pulley or a sprocket
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Braking Arrangements (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Abstract
A manual hoist and traction machine wherein an outer diameter of a first lining plate constituting a mechanical brake is made smaller than an inner diameter of a driven disc of a handwheel. The outer diameter of a second lining plate and of a driven disc are made smaller than an inner diameter of a cylindrical portion of a braking ratchet wheel, and the first and second lining plates are formed of a lining raw material having improved performance with a compressive strength of 15(Kgf/mm2) or more and a maximum strain of 12(10-3 mm/mm) or more.
Description
-~ ~6 5 5~
The pre~ent invention relates to a manual hoist and traction machine, and more particularly to a manual hoist and traction machine which is provided with a manually driving member mainly comprising a handwheel and with a mechanical brake operated by the manually driving member so that the manually driving member operates to rotatably drive a load sheave to hoist, haul, or lower a load, or to release traction thereof.
The conventional manual chain block, one of the manual hoist and traction machines, has been well-known as disclosed in, for example, the Japanese Utility Model Publication Gazette No. sho 54-39231.
The manual chain block disclosed in the above Gazette is so constructed that a driving shaft is supported between side plates through a pair of bearings. A load sheave in asso¢iation with the driving shaft through a reduction gear mechsnism is rotatably supported to the driving 6hsft. A driven member having at one side thereof a driven disc is coupled with the driving shaft. A boss bf a handwheel is screwably mounted to the driving shaft. And a braking ratchet wheel, engageable with a braking pawl, and a pair of lining plates, which are located confronting each other across the braking ratchet wheel, are supported on a cyli-ndrical portion of the driven member and between the driven disc and a side surface of a wheel portion of the handwheel, 80 as to constitute a mechanical brake. A
hand chain engaging with the handwheel is adapted to operate for rotatably driving the driving shaft through ~3~i58 the mechanical brake and drive the load sheave to hoist a load or release the mechanical brake to lower the hoisted load.
In the manual chain block constructed as mentioned above, commercially available lining plates, which are used for a brake lining for automobiles or the like, are used for the lining plate for the mechanical brake. And, the lining plate has a diameter approximately equal to that of the wheel portion of the handwheel and is located in opposition to the side surface of the wheel.
The brake lining generally used for industrial machines is only required to have at the best a property of a coefficient of friction of 0.20 or more at a friction surface temperature of 200~, compressive strength of 1000 (Kg/cm2 ) at the largest, and the maximum strain about 8 (10 3 mm/mm), in terms of its function, of which property comply with the provisions of Japanese Industrial Standard.
For use of those commercially available lining plates for the mechanical brake of the manual chain block, the lining plate must have a large in diameter and also the friction surface of the wheel opposite to the lining plate must have an increased area, in terms of performance and quality, so that a surface pressure can be decreased to work the mechanical brake property corresponding to a hoisted load.
On the other hand, the manual chain block has recently been required to be small-sized from the demand for ~ ~ ~ 6 !~ 5 8 simplicity in handling. To answer to the demand, the quality of material of each component has been improved to raise its durability. However, the handwheel is limited in downsizing its diameter due to a limitation of a diameter of the lining plate, and thus is restricted in its miniaturization. In addition, the handwheel must be set at the axially outside of the mechanical brake, so that the axial size of the handwheel also is limited in the miniaturization. Also, as the handwheel is axially outwardly positioned, a distance from a bearing supporting the driving shaft to the side plates to the handwheel becomes longer, and as a result, the driving shaft is subject to deflection by a load acting on the handwheel driven by the hand chain. Where the hand-chain is forcibly operated, the driving shaft may possibly be deformed. Also, in the no-load state where a hook at the load chain engaged with the load sheave hangs no load and the load sheave is not affected by the load, the body of the chain block, as shown by the two-dot chain line in Fig. 6, is slanted due to weight of the hand chain engageable with the handwheel. In this state, when the hand chain 100 is operated to rotate the handwheel 101, the hand chain 100 comes into contact with a wheel cover 103 at the chain block body 102 so as to generate noises. Besides, resistance is generated against the operation of hand chain 100 and resists an inertia rotation of the handwheel 101 by the operation of hand chain 100. Consequently, the ¢ . ~ -, : ~
~ ~ 3 6 5 ~5 8 7t ~ fi ~ ~ ~
hand wheel 101 can not be quickly rotated by the operation of the hand chain 100, and thereby the hook of the load chain cannot be lifted rapidly.
An object of the present invention is that in a manual chain block having a handwheel, the number of chain pockets on the handwheel can be minimized and also the wheel of the handwheel is lapped on the mechanical brake so that the handwheel can be axially positioned in proximity to a side of the side plate for supporting the load sheave and moreover a diameter of the wheel can be small so as to enable the chain block to be miniaturized.
Another object of the present invention is that in a manual hoist and traction machine including the above-mentioned manual chain block, the friction surface of the mechanical brake or an overload prevention device is improved to stabilize the performance thereof.
In order to attain the above-mentioned and other objects and advantages the invention is designed such that a manual hoist and traction machine comprises:
first and second side plates, a load sheave supported between those first and second side plates by first and second bearings, a driving shaft for driving the load sheave, and a driven member coupled with the driving shaft and having a friction surface. A driving member is threadedly mounted to the driving shaft and has a friction surface opposite to the friction surface of the driven member. A mechanical brake is provided between the driven member and the driving member, and comprises a braking ratchet wheel having friction surfaces at both axial sides.
A braking pawl is engageable with the braking ratchet wheel at an outer periphery thereof, and first and second lining plates are interposed between the friction surfaces of the driven member and braking ratchet wheel and between the friction surfaces of the braking ratchet wheel and driving member, respectively. Those lining plates comprise heat-resistant fiber, a friction regulating agent and a bonding agent, which are mixed in the ratio:
heat-resistant fiber = 28 to 35 (V ~) friction regulating agent = 20 to 37 (V ~) bonding agent = 35 to 45 (V ~) and have the following resultant characteristics:
hardness (HRS) = 90 to 120 bending strength (Kgf/mm2) = 9 to 15 maximum strain (10 mm/mm) = 12 to 16 compressive strength (Kgf/mm ) = 15 to 20 coefficient of friction (200~ C) = 0.25 to 0.60.
Preferrably, in the manual hoist and traction machine of this invention, the driving member comprises a handwheel provided with a wheel and boss threadedly mounted to the driving shaft and a hand chain engageable with the wheel of that handwheel. A side surface of the boss at the mechanical brake side has a friction surface, the wheel has a minimum number of pockets for receiving therein horizontal links of the hand chain, and the wheel has an inside-extending portion extending inwardly from the boss so as to be displaced toward the first side plate with respect to the friction surface at the boss. The hoist and traction machine is so assembled that an outer diameter of the first lining plate is smaller than an inner diameter of the inside-extending portion at the wheel. The braking ratchet wheel is provided with a cylindrical portion extending from the outer periphery of the ratchet wheel toward the side plate, the outer periphery of the cylindrical portion being provided with teeth with which the braking pawl comes into contact. The teeth are displaced toward the first side plate with respect to the inside-extending portion of the wheel, and outer diameters of the second lining plate and driven member are provided with friction surfaces which are smaller than an inner diameter of the cylindrical portion at the braking ratchet wheel.
- 4a -.~
_ ~'3~5~8-Other features and advantages of the invention will become more apparent from the following detailed description, in association with the accompanying drawings, in which:
Fig. 1 is a partial longitudinal sectional view o~ a first embodiment of the invention;
Fig. 2 is an enlarged sectional view of a principal portion of an embodiment, in which the friction surfaces of a mechanical brake are provided with a friction control layer;
Fig. 3 is an enlarged sectional view of the principal portion, showing a modified embodiment having the friction control layer;
Fig. 4 is a partial longitudinal sectional view of a second embodiment of the invention;
Fig. 5 is an enlarged sectional view of the principal portion of an embodiment in which the friction surfaces of an overload prevention device are provided with a friction control layer; and Fig. 6 is a schematic view of a conventional example, showing the problems of the prior art.
A manual chain block comprises a load sheave 3 supported between side plates 1 and 2 through a pair of bearings 5 and 6; a driving shaft 7 for driving the load sheave 3; a driven member 10 coupled with the driving shaft 7; a handwheel 11 screwably mounted on the driving shaft 7;
and a mechanical brake 17 provided between the driven member 10 and the handwheel 11 and having a braking ratchet wheel 12 engageable with a braking pawl 16 and a pair of lining plates 13 and 14. The handwheel 11 comprises a boss 19 screwably mounted to the driving shaft 7 and a wheel portion 20 having pockets in the minimum number for receiving therein horizontal links of the hand chain. An inside portion of the wheel portion 20 in continuation of a friction surface l9a of the boss 19 is swelled from the friction surface toward the side - 4b -5 ~ 8 plate. An outer diameter of the first lining plate 13 in contact with the friction surface is made smaller than an inner diameter of~ the inside swollen portion at the wheel portion 20. The braking ratchet wheel 12 is provided with a cylindrical portion 21 extending from the outer periphery thereof toward the side plate 1. The cylindrical portion 21 is provided, at the outer periphery thereof, with teeth 15 engageable with the braking pawl 16; the teeth 15 being displaced toward the side plate with resspect to the inside swollen portion of the wheel portion 20. Outer diameters of the second lining plate 14 and driven member 10 having the friction surface are made smaller than the inner diameter of the clindrical portion 21 of the braking ratchet wheel 12, and the first and second lining plates 13 and 14 are formed from a lining raw material comprising heat-resistant fiber, a friction regulating agen* and a bonding agent and having the performance such that, at a temperature of 200~ of the respective friction surfaces, the raw material has a coefficient of 0.35 or more, a hardness of 90 to 120, a compressive strength of 15(Kgf/mm2) and a maximum strain of 12 (103 mm/mm) or more.
Preferably, the cylindrical portion 21 at the braking ratchet wheel 12 is overlapped over the outer periphery of the bearing 6 supporting the load sheave 3 to the side plate 2.
Further, it is preferable that among the friction , . .
5 ~ ~
surfaces with which the first and second lining plates 13 and 14 come into friction contact, the friction surfaces on at least the driven member 10 and braking ratchet wheel are each provided with a friction control layer 26 plated and heat-treated.
Further, the invention may include an overload prevention device 30, which comprises a hand wheel 11 screwably mounted to a driving shaft 7 and a brake holder 31 having at the inside a flange 32 having at the inside a friction surface, and a cylindrical portion 33. A boss 19 of the handwheel 11 is supported to the cylindrical portion 33 of the brake holder 31, and a load setting and adjusting member 34 is screwably mounted thereto. Between the flange 32 of the brake holder 31 and the boss 19 is interposed a first friction plate 35. Between the boss 19 and the load setting and adjusting member 34 is interposed a second friction plate 36. Between the second friction plate 36 and the load setting and adjusting member 34 are interposed a holder plate 38 and an elastic member 37. The outer diameter of the flange 32 at the brake holder 31 and of the friction plates 35 and 36 are made smaller than an inner diameter of the inside swollen portion of the wheel portion 20.
Preferably, the outer diameters of the holding plate 38, elastic member 37 and load setting and adjusting member 34 in the overload prevention device 30 are made smaller than the inner diameter of the axially outside swollen .~
5 ~
portion of the wheel portion 20 of the handwheel 11, so that the overload prevention device 30 is contained in a plane of projection of both the axially side surfaces at the wheel portion 20 of the handwheel 11. Further, it is preferable that among the friction surfaces with which the first and second friction plates come into friction contact, the friction surfaces of at least the flanges 32 of the brake holder 31 and the holding plate 38 are provided thereon with a friction control layer 39 of a heat-treated plated layer.
According to the invention, the outer diameter of the first lining pate 13 is made smaller than an inner diameter of the inside swollen portion of the wheel portion 20 of the hand wheel 11. The braking ratchet wheel 12 is provided with the cylindrical portion 21, and teeth 15 engageable with the braking pawl 16 is displaced toward the side plate with respect to the inside swollen portion of 11. In addition to this, the outer diameters of the braking ratchet wheel 12 and lining plate 14 and driven member 10 provided with the friction surface are smaller than the inner diameter of the cylindrical portion 21, and also the first and second lining plates 13 and 14 are formed of the lining raw material mentioned above. This construction provides the result that while the handwheel 11 is made smaller, the axial position thereof is moved toward the load sheave 3, in other words, toward the side plate supporting to the load sheave. Accordingly, the size 5 S ~
not only in the radial direction but also in the axial direction can be reduced to downsize the chain block. Also, the driving shaft 7 is reduced in axial deflection.
Besides, the chain block is less slanted as a whole when not loaded, so that the handwheel can smoothly rotate by the force of inertia and the hand chain can be operated smoothly and rapidly without generating noises.
In addition, the construction, in which the cylindrical portion 21 of the braking ratchet wheel 12 is overlapped over the outer periphery of the bearing 6 supporting therethrough the load sheave 3 to the side plate 2, provides the result that the braking pawl 16 engageable with the teeth 15 at the cylindrical portion 21 is displaced toward the side plate and also the handwheel 11 can be displaced toward the same to that extent. This enables the chain block to be further reduced in axial length. Also, the driving shaft 7 can be reduced in deflection when the handwheel 11 is driven, and the entire chain block can be less slanted during the no loading.
Further, the construction that the friction control layer 26 is provided on the friction surface provides the result that the lining plate 13 and 14 of the abovesaid lining raw material have an improved attack resistance of the friction surface and a controlled coefficient of friction. Thus, even in long use, the coefficient of friction of the friction surface can be stabilized and the braking property can be prevented from being varied after ~;
5 5 ~ -long use, thereby enabling stable use to be performed for long time.
Furthermore, according to the invention including the overload prevention device 30, the outer diameter of the flange 32 of the brake holder 31 and those of the friction plates 35 and 36 are made smaller than the inner diameter of the inside swollen portion at the wheel portion 20 of the handwheel 11, so that the friction plates 35 and 36 can be contained in the plane of projection of the wheel portion 20 of the handwheel 11. Therefore, while the chain block includes the overload prevention device 30, it can be reduced in axial length to be downsized as a whole.
Furthermore, the construction, in which the outer diameters of the elastic member 37, holding plate 38 and load setting and adjusting member 34 at the overload prevention device 30 are made smaller than the inner diameter of the inside swollen portion of the wheel portion 20, so as to contain the overload prevention device 30 in the plane of projection at the wheel portion 20, provides the result that while providing the overload prevention device 30, the chain block can effectively be prevented from increasing in axial length.
Furthermore, the provision of the friction control layer 39 on the friction surface of the overload prevention device 30 enables the coefficient of friction of the friction surface to be controlled to be a desired value. Thus, a transmitting torque by the load setting and ~ _ g ~ .
S ~; ~ f adjusting member 34 can accurately be set, variation between the products is eliminated, and the surface condition of the friction surface is not affected easily by attack of friction plates 35 and 36 or by rust, thus enabling the set value of transmitting torque to be maintained properly for a long time.
The first embodiment of the invention shown in Figure 1 does not have the overload prevention device. A
8 ~
mounting shaft 4a for mounting a hook 4 is provided between a pair of side plates 1 and 2. A load sheave 3 engageable with a load chain 110 is rotatably supported between the side elates 1 and 2 through bearings 5 and 6.
A driving shaft 7 is inserted into a shaft bore of the load sheave 3. A driven member 10 comprising a driven disc 8 and a cylindrical portion 9 is coupled with the driving shaft 7 at the one axial side so as to rotate together with the driving shaft 7. A handwheel 11 is screwably mounted onto the one axial end of the driving shaft 7. At the cylindrical portion 9 of the driven member 10 are supported a braking ratchet wheel 12 and first and second lining plates 13 and 14 positioned at both axial sides of the braking ratchet wheel 12. A braking pawl 16 engageable with teeth 15 at the braking ratchet wheel 12 is supported through a pawl shaft 16a and a pawl spring 16b to the second plate 2. The driven member 10, handwheel 11, braking ratchet wheel 12, braking pawl 16, and the pair of first and second lining plates 13 and 14 form a mechanical brake 17. At the other axial side of the driving shaft 7 is provided a reduction gear mechanism 18 having a plurality of reduction gears.
In use, an endless hand chain 100 engageable with the handwheel 11 is operated to rotatably drive the handwheel 11 and a driving force is trans-mitted to the driving shaft 7 through operation of the mechanical brake 17 so as to drive the .~ .
load sheave 3 through the reduction gear mechanism 18, so as to hoist a load through the load chain 110 engaged with the load sheave 3.
The first embodiment of the invention shown in Fig.
is so constructed that in the manual chain block constructed as the above-mentioned, the handwheel 11 can be made smaller in diameter, displaced at the axial position toward the first side plate 1, and reduced not only in a radial length but also in an axial length, whereby, while the chain block can be downsized as a whole, deflection caused by a load acting on the handwheel 11 can be reduced and the entire chain block, when not-loaded, can be less slanted.
Specifically, the handwheel 11 is provided at the inside surface of a boss 19 with a friction surface l9a, and a wheel portion 20 in continuation of the boss 19 is axially extended toward the first side plate 1 with respect to the boss 19. At the wheel portion 20 are provided the minimum number of pockets 20a for receiving therein lateral links of the hand chain, and an outer diameter of each pocket is made smaller. As shown in Fig. 2, an outer diameter r1 of the first lining plate 13 in contact with the friction surface l9a is made smaller than an inner diameter R of the inside extended portion of the wheel portion 20. At the braking ratchet wheel 12 i5 provided a cylindrical portion 21 extending from the outer periphery thereof toward the load sheave 3 and overlapping over the 3~ 5 $8 outer periphery of the bearing 6, and at the outer periphery of the cylindrical portion 21 are provided teeth lS engageable with the braking pawl 16. The teeth 15 are thus di~placed toward the load sheave 3 with respect to the inside extended portion of the wheel portion 20. An outer diameter r2 of the second lining plate 14 and that r3 of the driven disc 8 at the driven member 10 are made smaller than an inner diameter r4 of the cylindrical portion 21. Also, the first and second lining plates 13 and 14 are formed of the following lining raw material.
The lining raw material comprises heat resistant fib~r, a friction regulating agent and a bonding agent, and has a coefficient of friction of 0.35 to 0.60 at a surface temperature of 200~ C
of the respective friction surfaces, a hardness (HRS) of 90 to 120, a compressive strength of 1500 (Kg/cm2) or more, and a maximum strain of 12 (10-3mm/mm) or more.
In the first embodiment shown in Fig.
1, the number of pockets at the handwheel 11 is six, the outer diameter r1 through r3 of the first lining plate 13, second lining plate 14 and driven disc 8 at the driven member 10, are equal to each other and also are made smaller than an outer diameter R of the inside swollen portion at the wheel portion 20 and smaller than an outer diameter of the bearing 6.
Inorganic fiber, such as, glass fiber, rock wool, metallic fiber, ceramic fiber, and carbon fiber: or .
.~
organic fiber, such as, alamode fiber, acrylic fiber, or phenol fiber is used for the heat resistant fiber constituting the first and second lining plates 13 and 14.
The friction regulating agent i~ powder or whiskers comprising metal, such as, iron, brass, copper, zinc, or aluminum; inorganic salt, such as, sulfate, barium sulfate, potassium carbonate, or potassium titanium;
or inorganic material, such as, graphite or carbon; or organic material, such as, rubber, fluororesin, high molecular phenol resin, or cashew dust. Further, $or the bonding agent is used a binder of resin material, such as, phenol resin, denatured phenol resin, polyimido resin, epoxy resin, cashew resin or melamine resin.
The heat resistant fiber is used as the aggregate and the friction regulating agent and bonding agent are mixed in the following ratio (volume %):
heat resistant fiber: 28 to 35 (V%) friction regulating agent: 20 to 37 (V%) bonding agent: 35 to 45 (V%) The lining raw material is molded to the lining plates 13 and 14 and pressurized a~d heated. The lining plates 13 and 14, which are formed of the materials mixed in the above-mentioned ratio, pressurized and heated, have the following performance:
hardness (HRS): 90 to 120 bending strength (Kgf/mmZ): 9 to 15 maximum strain (10 mm/mm): 12 to 16 ,~
r~ 5 compressive strength (Kgf/mm2): 15 to 20 coefficient of friction (200~): 0.35 to 0.60 Comparing the above-mentioned performance with that of the usual brake lining of resin series of non-asbestos, the compressive strength is particular stronger by 15 to 20 %, which is obtained by the heat resistant fiber and bonding agent being mixed in the ratio (V%) of 63 to 80%
to be larger than the ratio of usual brake lining and then molded by being pressurized and heated. Such performance permits the lining plates 13 and 14 at the mechanical brake 17 to be downsized which are tighened toward the driven disc & by forward screw movement of the handwheel 11 to function to transmit the driving force to the driving shaft 7.
Thus, since the lining plates 13 and 14 are reduced in diameter than the inner diameter R of the inside extended portion of the wheel portion 20 at the handwheel ll, the handwheel ll can be smaller in diameter. Moreover, in the embodiment shown in Fig. l, the cylindrical portion 21 of the braking ratchet wheel 12, as the above-mentioned, is overlapped over the outer periphery of the bearing 6 and the braking pawl 16 engageable with the teeth 15 at the cylindrical portion 21 can be displaced toward the first side plate 1. This construction serves the handwheel ll to be smaller in diameter and also serves its axial position to be displaced in proximity to the side plate l. As a result, the first lining plate 13 and the boss of braking . .
.~
ratchet wheel 12 can be contained within the plane of projection of the inside surface of the wheel 20 at the handwheel 11, thereby enabling the chain block to be reduced in axial length to that extent.
Thus, since the handwheel 11 can be miniaturized and its axial position can be displaced toward the side plate, the chain block can be miniaturized as a whole. And yet, since the handwheel 11 can be axially positioned at the side plate side, that is, near the bearing 6 at the side plate 1, when the handwheel 11 is driven by the hand chain, the driving shaft 7, subjected to a larger hoisted load, can be restrained from deflection and thus stable hoisting operation can be performed. Also, the entire chain block can be less slanted in the no-load state. Therefore, when the hand chain 100 is operated to rotate the handwheel 11 in the no-load state, the hand chain 100 is prevented from coming into contact with the wheel cover 25 so that it can be smoothly operated, and noises can be reduced. Also, the handwheel 11, when rotated by the hand chain 100, can be inertia-rotated, thereby enabling the handwheel 11 rotated by the hand chain 100 to quickly operate to that extent, and the hook of the load chain 110 to be quickly lifted.
It is to be noted that the number of pockets at the handwheel, which is six in the above-mentioned construction, may be five. Also, the minimum number of pockets means the number of pockets as represented by adding by one to the number of pockets above which " ?
3 ~
..".
variation in magnitude of power could become larger to hinder smooth operation of the hand chain 100 and thus lower the efficiency. It is to be noted further that the number of pockets depends on chain pitch of the hand chain.
In the pitch of 23.5 with a line diameter of 5mm or in the pitch of 28.0 with a line diameter of 6mm, the minimum number of pockets will be five.
The driving shaft 7 is supported at one axial end in a bearing 23 provided at a gear cover 22 for covering the reduction gear mechanism 18 and at the other axial end to a roller bearing 24 fitted into the shaft bore of the load sheave 3. A bearing may be provided at the wheel cover 25 for covering the handwheel 11 so that the extending shaft portion of the driving shaft 7 may be supported by the bearing.
Furthermore, it is preferable that in the above-mentioned construction, on the friction surfaces with which the first and second lining plates 13 and 14 come into contact, that is, on the friction surfaces of the braking ratchet wheel 12 and the driven disc 8 of the driven member 10, are provided plated layers of nickel phosphate, nickel chroe, or chrome, of 8 to 20 micron thick and then the plated layers are heat-treated to form friction control layers 26,-as shown in Fig. 3.
The friction control layers 26 each are not merely a plated layer, but a heat-treated, plated layer formed by heat-treating the plated layer in a heating furnace at a ~ 3~ 5 5~
temperature of 300 to 400~ C, or at the austenite transformation point temperature of, for example, 850~ C of each member constituting the friction surface, so as to diffuse and permeate the plated layer into the raw material of each member. The heat treatment raises the surface hardness and improves the attack resistance, and the coefficient of friction can be controlled to a predetermined value. Also, variation between the products can be reduced. Thus, even when used for a long time, the coefficient of friction of the friction surface can be stably maintained to prevent the braking property from deterioration after a long use and enable the stable use for a long time.
In addition, it is preferable that a friction control layer 26 is provided also at the friction surface l9a of the handwheel ll. In this case, a plated layer may be formed on the entire surface of the handwheel ll, while, as shown in Fig. 3, the boss l9 and wheel portion 20 may be independently formed and then coupled with a rivet 80 or the like, and thereafter the plated layer is formed on the entire surface of the boss l9. Alternatively, a contact plate (not shown) provided with a friction ~ control layer may be separately formed and integrally coupled with the boss l9 by riveting, a fixing method using adhesive, or the like.
Thus, the friction control layer 26 is provided at the friction surface l9a of the handwheel ll, so that, when ~ ~ 3~
the handwheel 11 is screwed backward to release the operation of mechanical brake 17, such releasing can be effected smoothly and a risk that the friction surface l9a is caught onto the lining plate 13 to cause not-releasing of the mechanical brake 17.
Also, in the case where the plated layer is heat-treated at the austenite transformation point temperature, it is preferable that the plated layer is quenched with cold water or cold oil after the heat treatment and thereafter is tempered at a temperature of 200 to 500~, normally 300 to 450~, so as to form a martensite structure.
Next, explanation will be given on a second embodiment of the invention shown in Fig. 4.
The second embodiment includes an overload prevention device 30, in which the handwheel 11 is provided with a brake holder 31 screwably mounted on the driving shaft 7 and comprising a flange 32 having at the inside a friction surface and a cylindrical portion 33. A boss 19 of the handwheel 11 is rotatably supported to the cylindrical portion 33 and a load setting and adjusting member 34 is screwably mounted thereto. Between the flange 32 of the brake holder 31 and the boss 19 is interposed a first friction plate 35, between the boss 19 and the load setting and adjusting member 34 is interposed a second friction plate 36, and between the second friction plate 36 and the load setting and adjusting member 34 is '.~
~ ~ -3 ~ 5 ~ ~
interposed an elastic member 37 mainly comprising a disc spring.
In the above-mentioned construction, outer diameters r of the flange 32, friction plates 35 and 36, the elastic member 37, load setting and adjusting member 34, and the holder plate 38 interposed between the second friction plate 36 and the elastic member 37 are made smaller than inner diameters R of the inside and outside extended portions of the wheel 20 at the handwheel 11, so that the overload prevention device 30 may be contained within the plane of projection of both axial side surfaces at the wheel 20 of the handwheel 11.
It is preferable to use the same lining raw material as the lining plates 13 and 14 at the mechanical brake 17.
In this case, it is preferable that the friction surfaces of the flange 32 of the brake holder 31 and the holder 38 with which the friction plates 35 and 36 come into frictional contact are, as shown in Fig. 5, provided with friction control layers.39 formed of plated layers of nickel phosphate, nickel chromium or chromium, and of 8 to 20 micron thick and heat-treated.
The friction control layers 39 each are not merely formed as the plate layer, as the same as those 26 at the friction surfaces of the mechanical brake 17, but are formed in such a manner that the plated layer is heat-treated in a heating furnace at a temperature of 300~ to ,~,, i i~
400~ C, or at the austentite transformation point temperature of, for example, 850~, of the above-mentioned members forming the friction surfaces, and diffused and permeated into the raw material of each member. The heat treatment raises the surface hardness and improves corrosion resistance and also controls the coefficient of friction to reduce variation between the products. Hence, a transmitting torque set by the load setting and adjusting member 34 can properly be maintained for a long time and proper slippage by an overload over the set transmitting torque can be ensured.
Preferably, the friction control layers are formed also on the friction surfaces of both sides of the boss 19 of the handwheel 11.
In this case, a plated layer may be formed on the entire surface of the hand wheel 11, while a friction plate provided with the friction control layer may be separately formed and then integrally coupled with the boss 19 by riveting or other proper fixing methods such as adhesive.
In the case where the plated layer is heat-treated at the austenite transformation point temperature, it is preferable that the plated layer is quenched with cold water or cold oil after the heat treatment, and thereafter is tempered at a temperature of 200~ to 500~ C, normally at 300~ to 450~ C, so as to form a martensite structure.
In the above-mentioned construction, the overload "7 -prevention device 30 is contained within the projection plane at both axial sides at the wheel portion 20 of the handwheel 11, so that the axial length of the chain block is reduced, while it includes the overload prevention device 30, and this serves for miniaturization of the entire chain block, in combination with the structure of the smaller-sized handwheel 11.
Also, in the second embodiment shown in Fig. 4, bearing is provided at the wheel cove~ 25 for covering the handwheel 11 and an extending axis 41 of the driving shaft 7 is supported to the bearing 40. And, the driving shaft 7 is supported at the opposite ends by the bearing 40 and the bearing 23 provided at the brake cover 22, with its intermediate portion inserted in the shaft bore of the load sheave 3 in such a manner as not to contact with the rotatably supported load sheave 3.
In addition, in Fig; 4, the reference numeral 42 designates a wheel holder inserted into the extending shaft portion 41 for restricting the handwheel 11 from moving axially outwardly, and 43 designates a one-way clutch for making the handwheel 11 rotate only in the normally driving direction.
The reduction gear mechanism 18 built in the first and second embodiments shown in Figs. 1 and 4 comprses a first gear 44 integrally formed at one axial end of the driving shaft 7, a pair of second gears engageable with the first gear 44 and supported to a pair of intermediate shafts 45, , ,. . ~ , a pair of third gears 47 provided at the intermediate shafts 45, and a fourth gear 48 coupled with an extension of the load sheave 3 and engageable with the third gears 47.
It is to be understood that the foregoing relates to only to preferred embodiments of the invention, and that various changes and modifications may be made in the invention without departing from the sprit and scope thereof.
The pre~ent invention relates to a manual hoist and traction machine, and more particularly to a manual hoist and traction machine which is provided with a manually driving member mainly comprising a handwheel and with a mechanical brake operated by the manually driving member so that the manually driving member operates to rotatably drive a load sheave to hoist, haul, or lower a load, or to release traction thereof.
The conventional manual chain block, one of the manual hoist and traction machines, has been well-known as disclosed in, for example, the Japanese Utility Model Publication Gazette No. sho 54-39231.
The manual chain block disclosed in the above Gazette is so constructed that a driving shaft is supported between side plates through a pair of bearings. A load sheave in asso¢iation with the driving shaft through a reduction gear mechsnism is rotatably supported to the driving 6hsft. A driven member having at one side thereof a driven disc is coupled with the driving shaft. A boss bf a handwheel is screwably mounted to the driving shaft. And a braking ratchet wheel, engageable with a braking pawl, and a pair of lining plates, which are located confronting each other across the braking ratchet wheel, are supported on a cyli-ndrical portion of the driven member and between the driven disc and a side surface of a wheel portion of the handwheel, 80 as to constitute a mechanical brake. A
hand chain engaging with the handwheel is adapted to operate for rotatably driving the driving shaft through ~3~i58 the mechanical brake and drive the load sheave to hoist a load or release the mechanical brake to lower the hoisted load.
In the manual chain block constructed as mentioned above, commercially available lining plates, which are used for a brake lining for automobiles or the like, are used for the lining plate for the mechanical brake. And, the lining plate has a diameter approximately equal to that of the wheel portion of the handwheel and is located in opposition to the side surface of the wheel.
The brake lining generally used for industrial machines is only required to have at the best a property of a coefficient of friction of 0.20 or more at a friction surface temperature of 200~, compressive strength of 1000 (Kg/cm2 ) at the largest, and the maximum strain about 8 (10 3 mm/mm), in terms of its function, of which property comply with the provisions of Japanese Industrial Standard.
For use of those commercially available lining plates for the mechanical brake of the manual chain block, the lining plate must have a large in diameter and also the friction surface of the wheel opposite to the lining plate must have an increased area, in terms of performance and quality, so that a surface pressure can be decreased to work the mechanical brake property corresponding to a hoisted load.
On the other hand, the manual chain block has recently been required to be small-sized from the demand for ~ ~ ~ 6 !~ 5 8 simplicity in handling. To answer to the demand, the quality of material of each component has been improved to raise its durability. However, the handwheel is limited in downsizing its diameter due to a limitation of a diameter of the lining plate, and thus is restricted in its miniaturization. In addition, the handwheel must be set at the axially outside of the mechanical brake, so that the axial size of the handwheel also is limited in the miniaturization. Also, as the handwheel is axially outwardly positioned, a distance from a bearing supporting the driving shaft to the side plates to the handwheel becomes longer, and as a result, the driving shaft is subject to deflection by a load acting on the handwheel driven by the hand chain. Where the hand-chain is forcibly operated, the driving shaft may possibly be deformed. Also, in the no-load state where a hook at the load chain engaged with the load sheave hangs no load and the load sheave is not affected by the load, the body of the chain block, as shown by the two-dot chain line in Fig. 6, is slanted due to weight of the hand chain engageable with the handwheel. In this state, when the hand chain 100 is operated to rotate the handwheel 101, the hand chain 100 comes into contact with a wheel cover 103 at the chain block body 102 so as to generate noises. Besides, resistance is generated against the operation of hand chain 100 and resists an inertia rotation of the handwheel 101 by the operation of hand chain 100. Consequently, the ¢ . ~ -, : ~
~ ~ 3 6 5 ~5 8 7t ~ fi ~ ~ ~
hand wheel 101 can not be quickly rotated by the operation of the hand chain 100, and thereby the hook of the load chain cannot be lifted rapidly.
An object of the present invention is that in a manual chain block having a handwheel, the number of chain pockets on the handwheel can be minimized and also the wheel of the handwheel is lapped on the mechanical brake so that the handwheel can be axially positioned in proximity to a side of the side plate for supporting the load sheave and moreover a diameter of the wheel can be small so as to enable the chain block to be miniaturized.
Another object of the present invention is that in a manual hoist and traction machine including the above-mentioned manual chain block, the friction surface of the mechanical brake or an overload prevention device is improved to stabilize the performance thereof.
In order to attain the above-mentioned and other objects and advantages the invention is designed such that a manual hoist and traction machine comprises:
first and second side plates, a load sheave supported between those first and second side plates by first and second bearings, a driving shaft for driving the load sheave, and a driven member coupled with the driving shaft and having a friction surface. A driving member is threadedly mounted to the driving shaft and has a friction surface opposite to the friction surface of the driven member. A mechanical brake is provided between the driven member and the driving member, and comprises a braking ratchet wheel having friction surfaces at both axial sides.
A braking pawl is engageable with the braking ratchet wheel at an outer periphery thereof, and first and second lining plates are interposed between the friction surfaces of the driven member and braking ratchet wheel and between the friction surfaces of the braking ratchet wheel and driving member, respectively. Those lining plates comprise heat-resistant fiber, a friction regulating agent and a bonding agent, which are mixed in the ratio:
heat-resistant fiber = 28 to 35 (V ~) friction regulating agent = 20 to 37 (V ~) bonding agent = 35 to 45 (V ~) and have the following resultant characteristics:
hardness (HRS) = 90 to 120 bending strength (Kgf/mm2) = 9 to 15 maximum strain (10 mm/mm) = 12 to 16 compressive strength (Kgf/mm ) = 15 to 20 coefficient of friction (200~ C) = 0.25 to 0.60.
Preferrably, in the manual hoist and traction machine of this invention, the driving member comprises a handwheel provided with a wheel and boss threadedly mounted to the driving shaft and a hand chain engageable with the wheel of that handwheel. A side surface of the boss at the mechanical brake side has a friction surface, the wheel has a minimum number of pockets for receiving therein horizontal links of the hand chain, and the wheel has an inside-extending portion extending inwardly from the boss so as to be displaced toward the first side plate with respect to the friction surface at the boss. The hoist and traction machine is so assembled that an outer diameter of the first lining plate is smaller than an inner diameter of the inside-extending portion at the wheel. The braking ratchet wheel is provided with a cylindrical portion extending from the outer periphery of the ratchet wheel toward the side plate, the outer periphery of the cylindrical portion being provided with teeth with which the braking pawl comes into contact. The teeth are displaced toward the first side plate with respect to the inside-extending portion of the wheel, and outer diameters of the second lining plate and driven member are provided with friction surfaces which are smaller than an inner diameter of the cylindrical portion at the braking ratchet wheel.
- 4a -.~
_ ~'3~5~8-Other features and advantages of the invention will become more apparent from the following detailed description, in association with the accompanying drawings, in which:
Fig. 1 is a partial longitudinal sectional view o~ a first embodiment of the invention;
Fig. 2 is an enlarged sectional view of a principal portion of an embodiment, in which the friction surfaces of a mechanical brake are provided with a friction control layer;
Fig. 3 is an enlarged sectional view of the principal portion, showing a modified embodiment having the friction control layer;
Fig. 4 is a partial longitudinal sectional view of a second embodiment of the invention;
Fig. 5 is an enlarged sectional view of the principal portion of an embodiment in which the friction surfaces of an overload prevention device are provided with a friction control layer; and Fig. 6 is a schematic view of a conventional example, showing the problems of the prior art.
A manual chain block comprises a load sheave 3 supported between side plates 1 and 2 through a pair of bearings 5 and 6; a driving shaft 7 for driving the load sheave 3; a driven member 10 coupled with the driving shaft 7; a handwheel 11 screwably mounted on the driving shaft 7;
and a mechanical brake 17 provided between the driven member 10 and the handwheel 11 and having a braking ratchet wheel 12 engageable with a braking pawl 16 and a pair of lining plates 13 and 14. The handwheel 11 comprises a boss 19 screwably mounted to the driving shaft 7 and a wheel portion 20 having pockets in the minimum number for receiving therein horizontal links of the hand chain. An inside portion of the wheel portion 20 in continuation of a friction surface l9a of the boss 19 is swelled from the friction surface toward the side - 4b -5 ~ 8 plate. An outer diameter of the first lining plate 13 in contact with the friction surface is made smaller than an inner diameter of~ the inside swollen portion at the wheel portion 20. The braking ratchet wheel 12 is provided with a cylindrical portion 21 extending from the outer periphery thereof toward the side plate 1. The cylindrical portion 21 is provided, at the outer periphery thereof, with teeth 15 engageable with the braking pawl 16; the teeth 15 being displaced toward the side plate with resspect to the inside swollen portion of the wheel portion 20. Outer diameters of the second lining plate 14 and driven member 10 having the friction surface are made smaller than the inner diameter of the clindrical portion 21 of the braking ratchet wheel 12, and the first and second lining plates 13 and 14 are formed from a lining raw material comprising heat-resistant fiber, a friction regulating agen* and a bonding agent and having the performance such that, at a temperature of 200~ of the respective friction surfaces, the raw material has a coefficient of 0.35 or more, a hardness of 90 to 120, a compressive strength of 15(Kgf/mm2) and a maximum strain of 12 (103 mm/mm) or more.
Preferably, the cylindrical portion 21 at the braking ratchet wheel 12 is overlapped over the outer periphery of the bearing 6 supporting the load sheave 3 to the side plate 2.
Further, it is preferable that among the friction , . .
5 ~ ~
surfaces with which the first and second lining plates 13 and 14 come into friction contact, the friction surfaces on at least the driven member 10 and braking ratchet wheel are each provided with a friction control layer 26 plated and heat-treated.
Further, the invention may include an overload prevention device 30, which comprises a hand wheel 11 screwably mounted to a driving shaft 7 and a brake holder 31 having at the inside a flange 32 having at the inside a friction surface, and a cylindrical portion 33. A boss 19 of the handwheel 11 is supported to the cylindrical portion 33 of the brake holder 31, and a load setting and adjusting member 34 is screwably mounted thereto. Between the flange 32 of the brake holder 31 and the boss 19 is interposed a first friction plate 35. Between the boss 19 and the load setting and adjusting member 34 is interposed a second friction plate 36. Between the second friction plate 36 and the load setting and adjusting member 34 are interposed a holder plate 38 and an elastic member 37. The outer diameter of the flange 32 at the brake holder 31 and of the friction plates 35 and 36 are made smaller than an inner diameter of the inside swollen portion of the wheel portion 20.
Preferably, the outer diameters of the holding plate 38, elastic member 37 and load setting and adjusting member 34 in the overload prevention device 30 are made smaller than the inner diameter of the axially outside swollen .~
5 ~
portion of the wheel portion 20 of the handwheel 11, so that the overload prevention device 30 is contained in a plane of projection of both the axially side surfaces at the wheel portion 20 of the handwheel 11. Further, it is preferable that among the friction surfaces with which the first and second friction plates come into friction contact, the friction surfaces of at least the flanges 32 of the brake holder 31 and the holding plate 38 are provided thereon with a friction control layer 39 of a heat-treated plated layer.
According to the invention, the outer diameter of the first lining pate 13 is made smaller than an inner diameter of the inside swollen portion of the wheel portion 20 of the hand wheel 11. The braking ratchet wheel 12 is provided with the cylindrical portion 21, and teeth 15 engageable with the braking pawl 16 is displaced toward the side plate with respect to the inside swollen portion of 11. In addition to this, the outer diameters of the braking ratchet wheel 12 and lining plate 14 and driven member 10 provided with the friction surface are smaller than the inner diameter of the cylindrical portion 21, and also the first and second lining plates 13 and 14 are formed of the lining raw material mentioned above. This construction provides the result that while the handwheel 11 is made smaller, the axial position thereof is moved toward the load sheave 3, in other words, toward the side plate supporting to the load sheave. Accordingly, the size 5 S ~
not only in the radial direction but also in the axial direction can be reduced to downsize the chain block. Also, the driving shaft 7 is reduced in axial deflection.
Besides, the chain block is less slanted as a whole when not loaded, so that the handwheel can smoothly rotate by the force of inertia and the hand chain can be operated smoothly and rapidly without generating noises.
In addition, the construction, in which the cylindrical portion 21 of the braking ratchet wheel 12 is overlapped over the outer periphery of the bearing 6 supporting therethrough the load sheave 3 to the side plate 2, provides the result that the braking pawl 16 engageable with the teeth 15 at the cylindrical portion 21 is displaced toward the side plate and also the handwheel 11 can be displaced toward the same to that extent. This enables the chain block to be further reduced in axial length. Also, the driving shaft 7 can be reduced in deflection when the handwheel 11 is driven, and the entire chain block can be less slanted during the no loading.
Further, the construction that the friction control layer 26 is provided on the friction surface provides the result that the lining plate 13 and 14 of the abovesaid lining raw material have an improved attack resistance of the friction surface and a controlled coefficient of friction. Thus, even in long use, the coefficient of friction of the friction surface can be stabilized and the braking property can be prevented from being varied after ~;
5 5 ~ -long use, thereby enabling stable use to be performed for long time.
Furthermore, according to the invention including the overload prevention device 30, the outer diameter of the flange 32 of the brake holder 31 and those of the friction plates 35 and 36 are made smaller than the inner diameter of the inside swollen portion at the wheel portion 20 of the handwheel 11, so that the friction plates 35 and 36 can be contained in the plane of projection of the wheel portion 20 of the handwheel 11. Therefore, while the chain block includes the overload prevention device 30, it can be reduced in axial length to be downsized as a whole.
Furthermore, the construction, in which the outer diameters of the elastic member 37, holding plate 38 and load setting and adjusting member 34 at the overload prevention device 30 are made smaller than the inner diameter of the inside swollen portion of the wheel portion 20, so as to contain the overload prevention device 30 in the plane of projection at the wheel portion 20, provides the result that while providing the overload prevention device 30, the chain block can effectively be prevented from increasing in axial length.
Furthermore, the provision of the friction control layer 39 on the friction surface of the overload prevention device 30 enables the coefficient of friction of the friction surface to be controlled to be a desired value. Thus, a transmitting torque by the load setting and ~ _ g ~ .
S ~; ~ f adjusting member 34 can accurately be set, variation between the products is eliminated, and the surface condition of the friction surface is not affected easily by attack of friction plates 35 and 36 or by rust, thus enabling the set value of transmitting torque to be maintained properly for a long time.
The first embodiment of the invention shown in Figure 1 does not have the overload prevention device. A
8 ~
mounting shaft 4a for mounting a hook 4 is provided between a pair of side plates 1 and 2. A load sheave 3 engageable with a load chain 110 is rotatably supported between the side elates 1 and 2 through bearings 5 and 6.
A driving shaft 7 is inserted into a shaft bore of the load sheave 3. A driven member 10 comprising a driven disc 8 and a cylindrical portion 9 is coupled with the driving shaft 7 at the one axial side so as to rotate together with the driving shaft 7. A handwheel 11 is screwably mounted onto the one axial end of the driving shaft 7. At the cylindrical portion 9 of the driven member 10 are supported a braking ratchet wheel 12 and first and second lining plates 13 and 14 positioned at both axial sides of the braking ratchet wheel 12. A braking pawl 16 engageable with teeth 15 at the braking ratchet wheel 12 is supported through a pawl shaft 16a and a pawl spring 16b to the second plate 2. The driven member 10, handwheel 11, braking ratchet wheel 12, braking pawl 16, and the pair of first and second lining plates 13 and 14 form a mechanical brake 17. At the other axial side of the driving shaft 7 is provided a reduction gear mechanism 18 having a plurality of reduction gears.
In use, an endless hand chain 100 engageable with the handwheel 11 is operated to rotatably drive the handwheel 11 and a driving force is trans-mitted to the driving shaft 7 through operation of the mechanical brake 17 so as to drive the .~ .
load sheave 3 through the reduction gear mechanism 18, so as to hoist a load through the load chain 110 engaged with the load sheave 3.
The first embodiment of the invention shown in Fig.
is so constructed that in the manual chain block constructed as the above-mentioned, the handwheel 11 can be made smaller in diameter, displaced at the axial position toward the first side plate 1, and reduced not only in a radial length but also in an axial length, whereby, while the chain block can be downsized as a whole, deflection caused by a load acting on the handwheel 11 can be reduced and the entire chain block, when not-loaded, can be less slanted.
Specifically, the handwheel 11 is provided at the inside surface of a boss 19 with a friction surface l9a, and a wheel portion 20 in continuation of the boss 19 is axially extended toward the first side plate 1 with respect to the boss 19. At the wheel portion 20 are provided the minimum number of pockets 20a for receiving therein lateral links of the hand chain, and an outer diameter of each pocket is made smaller. As shown in Fig. 2, an outer diameter r1 of the first lining plate 13 in contact with the friction surface l9a is made smaller than an inner diameter R of the inside extended portion of the wheel portion 20. At the braking ratchet wheel 12 i5 provided a cylindrical portion 21 extending from the outer periphery thereof toward the load sheave 3 and overlapping over the 3~ 5 $8 outer periphery of the bearing 6, and at the outer periphery of the cylindrical portion 21 are provided teeth lS engageable with the braking pawl 16. The teeth 15 are thus di~placed toward the load sheave 3 with respect to the inside extended portion of the wheel portion 20. An outer diameter r2 of the second lining plate 14 and that r3 of the driven disc 8 at the driven member 10 are made smaller than an inner diameter r4 of the cylindrical portion 21. Also, the first and second lining plates 13 and 14 are formed of the following lining raw material.
The lining raw material comprises heat resistant fib~r, a friction regulating agent and a bonding agent, and has a coefficient of friction of 0.35 to 0.60 at a surface temperature of 200~ C
of the respective friction surfaces, a hardness (HRS) of 90 to 120, a compressive strength of 1500 (Kg/cm2) or more, and a maximum strain of 12 (10-3mm/mm) or more.
In the first embodiment shown in Fig.
1, the number of pockets at the handwheel 11 is six, the outer diameter r1 through r3 of the first lining plate 13, second lining plate 14 and driven disc 8 at the driven member 10, are equal to each other and also are made smaller than an outer diameter R of the inside swollen portion at the wheel portion 20 and smaller than an outer diameter of the bearing 6.
Inorganic fiber, such as, glass fiber, rock wool, metallic fiber, ceramic fiber, and carbon fiber: or .
.~
organic fiber, such as, alamode fiber, acrylic fiber, or phenol fiber is used for the heat resistant fiber constituting the first and second lining plates 13 and 14.
The friction regulating agent i~ powder or whiskers comprising metal, such as, iron, brass, copper, zinc, or aluminum; inorganic salt, such as, sulfate, barium sulfate, potassium carbonate, or potassium titanium;
or inorganic material, such as, graphite or carbon; or organic material, such as, rubber, fluororesin, high molecular phenol resin, or cashew dust. Further, $or the bonding agent is used a binder of resin material, such as, phenol resin, denatured phenol resin, polyimido resin, epoxy resin, cashew resin or melamine resin.
The heat resistant fiber is used as the aggregate and the friction regulating agent and bonding agent are mixed in the following ratio (volume %):
heat resistant fiber: 28 to 35 (V%) friction regulating agent: 20 to 37 (V%) bonding agent: 35 to 45 (V%) The lining raw material is molded to the lining plates 13 and 14 and pressurized a~d heated. The lining plates 13 and 14, which are formed of the materials mixed in the above-mentioned ratio, pressurized and heated, have the following performance:
hardness (HRS): 90 to 120 bending strength (Kgf/mmZ): 9 to 15 maximum strain (10 mm/mm): 12 to 16 ,~
r~ 5 compressive strength (Kgf/mm2): 15 to 20 coefficient of friction (200~): 0.35 to 0.60 Comparing the above-mentioned performance with that of the usual brake lining of resin series of non-asbestos, the compressive strength is particular stronger by 15 to 20 %, which is obtained by the heat resistant fiber and bonding agent being mixed in the ratio (V%) of 63 to 80%
to be larger than the ratio of usual brake lining and then molded by being pressurized and heated. Such performance permits the lining plates 13 and 14 at the mechanical brake 17 to be downsized which are tighened toward the driven disc & by forward screw movement of the handwheel 11 to function to transmit the driving force to the driving shaft 7.
Thus, since the lining plates 13 and 14 are reduced in diameter than the inner diameter R of the inside extended portion of the wheel portion 20 at the handwheel ll, the handwheel ll can be smaller in diameter. Moreover, in the embodiment shown in Fig. l, the cylindrical portion 21 of the braking ratchet wheel 12, as the above-mentioned, is overlapped over the outer periphery of the bearing 6 and the braking pawl 16 engageable with the teeth 15 at the cylindrical portion 21 can be displaced toward the first side plate 1. This construction serves the handwheel ll to be smaller in diameter and also serves its axial position to be displaced in proximity to the side plate l. As a result, the first lining plate 13 and the boss of braking . .
.~
ratchet wheel 12 can be contained within the plane of projection of the inside surface of the wheel 20 at the handwheel 11, thereby enabling the chain block to be reduced in axial length to that extent.
Thus, since the handwheel 11 can be miniaturized and its axial position can be displaced toward the side plate, the chain block can be miniaturized as a whole. And yet, since the handwheel 11 can be axially positioned at the side plate side, that is, near the bearing 6 at the side plate 1, when the handwheel 11 is driven by the hand chain, the driving shaft 7, subjected to a larger hoisted load, can be restrained from deflection and thus stable hoisting operation can be performed. Also, the entire chain block can be less slanted in the no-load state. Therefore, when the hand chain 100 is operated to rotate the handwheel 11 in the no-load state, the hand chain 100 is prevented from coming into contact with the wheel cover 25 so that it can be smoothly operated, and noises can be reduced. Also, the handwheel 11, when rotated by the hand chain 100, can be inertia-rotated, thereby enabling the handwheel 11 rotated by the hand chain 100 to quickly operate to that extent, and the hook of the load chain 110 to be quickly lifted.
It is to be noted that the number of pockets at the handwheel, which is six in the above-mentioned construction, may be five. Also, the minimum number of pockets means the number of pockets as represented by adding by one to the number of pockets above which " ?
3 ~
..".
variation in magnitude of power could become larger to hinder smooth operation of the hand chain 100 and thus lower the efficiency. It is to be noted further that the number of pockets depends on chain pitch of the hand chain.
In the pitch of 23.5 with a line diameter of 5mm or in the pitch of 28.0 with a line diameter of 6mm, the minimum number of pockets will be five.
The driving shaft 7 is supported at one axial end in a bearing 23 provided at a gear cover 22 for covering the reduction gear mechanism 18 and at the other axial end to a roller bearing 24 fitted into the shaft bore of the load sheave 3. A bearing may be provided at the wheel cover 25 for covering the handwheel 11 so that the extending shaft portion of the driving shaft 7 may be supported by the bearing.
Furthermore, it is preferable that in the above-mentioned construction, on the friction surfaces with which the first and second lining plates 13 and 14 come into contact, that is, on the friction surfaces of the braking ratchet wheel 12 and the driven disc 8 of the driven member 10, are provided plated layers of nickel phosphate, nickel chroe, or chrome, of 8 to 20 micron thick and then the plated layers are heat-treated to form friction control layers 26,-as shown in Fig. 3.
The friction control layers 26 each are not merely a plated layer, but a heat-treated, plated layer formed by heat-treating the plated layer in a heating furnace at a ~ 3~ 5 5~
temperature of 300 to 400~ C, or at the austenite transformation point temperature of, for example, 850~ C of each member constituting the friction surface, so as to diffuse and permeate the plated layer into the raw material of each member. The heat treatment raises the surface hardness and improves the attack resistance, and the coefficient of friction can be controlled to a predetermined value. Also, variation between the products can be reduced. Thus, even when used for a long time, the coefficient of friction of the friction surface can be stably maintained to prevent the braking property from deterioration after a long use and enable the stable use for a long time.
In addition, it is preferable that a friction control layer 26 is provided also at the friction surface l9a of the handwheel ll. In this case, a plated layer may be formed on the entire surface of the handwheel ll, while, as shown in Fig. 3, the boss l9 and wheel portion 20 may be independently formed and then coupled with a rivet 80 or the like, and thereafter the plated layer is formed on the entire surface of the boss l9. Alternatively, a contact plate (not shown) provided with a friction ~ control layer may be separately formed and integrally coupled with the boss l9 by riveting, a fixing method using adhesive, or the like.
Thus, the friction control layer 26 is provided at the friction surface l9a of the handwheel ll, so that, when ~ ~ 3~
the handwheel 11 is screwed backward to release the operation of mechanical brake 17, such releasing can be effected smoothly and a risk that the friction surface l9a is caught onto the lining plate 13 to cause not-releasing of the mechanical brake 17.
Also, in the case where the plated layer is heat-treated at the austenite transformation point temperature, it is preferable that the plated layer is quenched with cold water or cold oil after the heat treatment and thereafter is tempered at a temperature of 200 to 500~, normally 300 to 450~, so as to form a martensite structure.
Next, explanation will be given on a second embodiment of the invention shown in Fig. 4.
The second embodiment includes an overload prevention device 30, in which the handwheel 11 is provided with a brake holder 31 screwably mounted on the driving shaft 7 and comprising a flange 32 having at the inside a friction surface and a cylindrical portion 33. A boss 19 of the handwheel 11 is rotatably supported to the cylindrical portion 33 and a load setting and adjusting member 34 is screwably mounted thereto. Between the flange 32 of the brake holder 31 and the boss 19 is interposed a first friction plate 35, between the boss 19 and the load setting and adjusting member 34 is interposed a second friction plate 36, and between the second friction plate 36 and the load setting and adjusting member 34 is '.~
~ ~ -3 ~ 5 ~ ~
interposed an elastic member 37 mainly comprising a disc spring.
In the above-mentioned construction, outer diameters r of the flange 32, friction plates 35 and 36, the elastic member 37, load setting and adjusting member 34, and the holder plate 38 interposed between the second friction plate 36 and the elastic member 37 are made smaller than inner diameters R of the inside and outside extended portions of the wheel 20 at the handwheel 11, so that the overload prevention device 30 may be contained within the plane of projection of both axial side surfaces at the wheel 20 of the handwheel 11.
It is preferable to use the same lining raw material as the lining plates 13 and 14 at the mechanical brake 17.
In this case, it is preferable that the friction surfaces of the flange 32 of the brake holder 31 and the holder 38 with which the friction plates 35 and 36 come into frictional contact are, as shown in Fig. 5, provided with friction control layers.39 formed of plated layers of nickel phosphate, nickel chromium or chromium, and of 8 to 20 micron thick and heat-treated.
The friction control layers 39 each are not merely formed as the plate layer, as the same as those 26 at the friction surfaces of the mechanical brake 17, but are formed in such a manner that the plated layer is heat-treated in a heating furnace at a temperature of 300~ to ,~,, i i~
400~ C, or at the austentite transformation point temperature of, for example, 850~, of the above-mentioned members forming the friction surfaces, and diffused and permeated into the raw material of each member. The heat treatment raises the surface hardness and improves corrosion resistance and also controls the coefficient of friction to reduce variation between the products. Hence, a transmitting torque set by the load setting and adjusting member 34 can properly be maintained for a long time and proper slippage by an overload over the set transmitting torque can be ensured.
Preferably, the friction control layers are formed also on the friction surfaces of both sides of the boss 19 of the handwheel 11.
In this case, a plated layer may be formed on the entire surface of the hand wheel 11, while a friction plate provided with the friction control layer may be separately formed and then integrally coupled with the boss 19 by riveting or other proper fixing methods such as adhesive.
In the case where the plated layer is heat-treated at the austenite transformation point temperature, it is preferable that the plated layer is quenched with cold water or cold oil after the heat treatment, and thereafter is tempered at a temperature of 200~ to 500~ C, normally at 300~ to 450~ C, so as to form a martensite structure.
In the above-mentioned construction, the overload "7 -prevention device 30 is contained within the projection plane at both axial sides at the wheel portion 20 of the handwheel 11, so that the axial length of the chain block is reduced, while it includes the overload prevention device 30, and this serves for miniaturization of the entire chain block, in combination with the structure of the smaller-sized handwheel 11.
Also, in the second embodiment shown in Fig. 4, bearing is provided at the wheel cove~ 25 for covering the handwheel 11 and an extending axis 41 of the driving shaft 7 is supported to the bearing 40. And, the driving shaft 7 is supported at the opposite ends by the bearing 40 and the bearing 23 provided at the brake cover 22, with its intermediate portion inserted in the shaft bore of the load sheave 3 in such a manner as not to contact with the rotatably supported load sheave 3.
In addition, in Fig; 4, the reference numeral 42 designates a wheel holder inserted into the extending shaft portion 41 for restricting the handwheel 11 from moving axially outwardly, and 43 designates a one-way clutch for making the handwheel 11 rotate only in the normally driving direction.
The reduction gear mechanism 18 built in the first and second embodiments shown in Figs. 1 and 4 comprses a first gear 44 integrally formed at one axial end of the driving shaft 7, a pair of second gears engageable with the first gear 44 and supported to a pair of intermediate shafts 45, , ,. . ~ , a pair of third gears 47 provided at the intermediate shafts 45, and a fourth gear 48 coupled with an extension of the load sheave 3 and engageable with the third gears 47.
It is to be understood that the foregoing relates to only to preferred embodiments of the invention, and that various changes and modifications may be made in the invention without departing from the sprit and scope thereof.
Claims (10)
1. A manual hoist and traction machine comprising:
first and second side plates;
a load sheave supported between said first and second side plates by first and second bearings;
a driving shaft for driving said load sheave;
a driven member coupled with said driving shaft and having a friction surface;
a driving member threadedly mounted to said driving shaft and having a friction surface opposite to the friction surface of said driven member;
a mechanical brake provided between said driven member and said driving member and comprising a braking ratchet wheel having friction surfaces at both axial sides;
a braking pawl engageable with said braking ratchet wheel at an outer periphery thereof; and first and second lining plates interposed between the friction surfaces of said driven member and braking ratchet wheel and between the friction surfaces of said braking ratchet wheel and driving member, respectively;
wherein said lining plates comprise heat-resistant fiber, a friction regulating agent and a bonding agent, which are mixed in the ratio:
heat-resistant fiber = 28 to 35 (V %) friction regulating agent = 20 to 37 (V %) bonding agent = 35 to 45 (V %) and have the following resultant characteristics:
hardness (HRS) = 90 to 120 bending strength (Kgf/mm2) = 9 to 15 maximum strain (10 -3 mm/mm) = 12 to 16 compressive strength (Kgf/mm2) = 15 to 20 coefficient of friction (200° C) = 0.25 to 0.60.
first and second side plates;
a load sheave supported between said first and second side plates by first and second bearings;
a driving shaft for driving said load sheave;
a driven member coupled with said driving shaft and having a friction surface;
a driving member threadedly mounted to said driving shaft and having a friction surface opposite to the friction surface of said driven member;
a mechanical brake provided between said driven member and said driving member and comprising a braking ratchet wheel having friction surfaces at both axial sides;
a braking pawl engageable with said braking ratchet wheel at an outer periphery thereof; and first and second lining plates interposed between the friction surfaces of said driven member and braking ratchet wheel and between the friction surfaces of said braking ratchet wheel and driving member, respectively;
wherein said lining plates comprise heat-resistant fiber, a friction regulating agent and a bonding agent, which are mixed in the ratio:
heat-resistant fiber = 28 to 35 (V %) friction regulating agent = 20 to 37 (V %) bonding agent = 35 to 45 (V %) and have the following resultant characteristics:
hardness (HRS) = 90 to 120 bending strength (Kgf/mm2) = 9 to 15 maximum strain (10 -3 mm/mm) = 12 to 16 compressive strength (Kgf/mm2) = 15 to 20 coefficient of friction (200° C) = 0.25 to 0.60.
2. A manual hoist and traction machine according to claim 1, wherein:
said driving member comprises a handwheel provided with a wheel and boss threadedly mounted to said driving shaft and a hand chain engageable with said wheel of said handwheel, a side surface of said boss at the mechanical brake side having a friction surface, said wheel having a minimum number of pockets for receiving therein horizontal links of said hand chain, and said wheel having an inside-extending portion extending inwardly from said boss so as to be displaced toward said first side plate with respect to said friction surface at said boss;
said hoist and traction machine being so assembled that an outer diameter of said first lining plate is smaller than an inner diameter of said inside-extending portion at said wheel; and said braking ratchet wheel being provided with a cylindrical portion extending from the outer periphery of said ratchet wheel toward said side plate, the outer periphery of said cylindrical portion being provided with teeth with which said braking pawl comes into contact, said teeth being displaced toward said first side plate with respect to said inside-extending portion of said wheel, and outer diameters of said second lining plate and driven member being provided with said friction surfaces which are smaller than an inner diameter of said cylindrical portion at said braking ratchet wheel.
said driving member comprises a handwheel provided with a wheel and boss threadedly mounted to said driving shaft and a hand chain engageable with said wheel of said handwheel, a side surface of said boss at the mechanical brake side having a friction surface, said wheel having a minimum number of pockets for receiving therein horizontal links of said hand chain, and said wheel having an inside-extending portion extending inwardly from said boss so as to be displaced toward said first side plate with respect to said friction surface at said boss;
said hoist and traction machine being so assembled that an outer diameter of said first lining plate is smaller than an inner diameter of said inside-extending portion at said wheel; and said braking ratchet wheel being provided with a cylindrical portion extending from the outer periphery of said ratchet wheel toward said side plate, the outer periphery of said cylindrical portion being provided with teeth with which said braking pawl comes into contact, said teeth being displaced toward said first side plate with respect to said inside-extending portion of said wheel, and outer diameters of said second lining plate and driven member being provided with said friction surfaces which are smaller than an inner diameter of said cylindrical portion at said braking ratchet wheel.
3. A manual hoist and traction machine according to claim 2, wherein said cylindrical portion of said braking ratchet wheel is partly extended inwardly beyond an outer periphery of said first bearing by which said load sheave is supported to said first side plate.
4. A manual hoist and traction machine according to claim 2 or 3, wherein the friction surfaces on at least said driven member and braking ratchet wheel with which said first and second lining plates are axially biased by forward screw movement of said handwheel so as to come into frictional contact are provided with friction control layers comprising plated layers, said plated layers being heat-treated.
5. A manual hoist and traction machine according to claim 1, wherein said driving member comprises a brake holder screwably mounted to said driving shaft and having a cylindrical portion and a flange having at the inside surface thereof a friction surface, a handwheel with a boss having at both axial sides thereof friction surfaces and an inside-extending portion and rotatably supported to said cylindrical portion of said brake holder, and a hand chain engageable with said handwheel, and in which to said cylindrical portion at said brake holder is screwably mounted a load setting and adjusting member, a first friction plate is interposed between said flange of said brake holder and said boss of said handwheel, a second friction plate is interposed between said boss and said load setting and adjusting member, and a holding plate and an elastic member are interposed between said second friction plate and said load setting and adjusting member, thereby forming an overload preventing device, and outer diameters of said flange at said brake holder and first and second friction plates are made smaller than an inner diameter of said inside-extending portion at said handwheel.
6. A manual hoist and traction machine according to claim 5, wherein the outer diameter of said elastic member, said holding plate and said load setting and adjusting member at said overload prevention device are smaller than the inner diameter of said extending portion at the an axially-outside surface, and said overload prevention device is contained within the plane of projection of both said axial surfaces at said wheel of said handwheel.
7. A manual hoist and traction machine according to claim 5 or 6, wherein said friction surfaces of at least said flange of said brake holder and of said holding plate among said friction surfaces with which said first and second friction plates come into frictional contact are provided with friction control layers comprising heat-treated plated layers.
8. A manual hoist and traction machine according to claim 1, wherein said driving member comprises a brake holder screwably mounted to said driving shaft and having a cylindrical portion and a flange having at the inside surface thereof a friction surface, a driving gear which has a boss having at both axial sides thereof friction surfaces, and teeth positioned at the outer periphery; and including an operating lever having a driving pawl engageable with said teeth at said driving gear, and in which to said cylindrical portion of said brake holder is screwably mounted a load setting and adjusting member, between said flange of said brake holder and the boss of said driving gear is interposed a first friction plate, between said boss of said driving gear and said load setting and adjusting member is interposed a second friction plate, and between said second friction plate and said load setting and adjusting member are interposed a holding plate having a friction surface and an elastic member to thereby form an overload prevention device, and the friction plates of said flange at said brake holder, driving gear and holding plate, are each provided with a friction control layer formed of a plated layer which is heat-treated.
9. A manual hoist and traction machine according to claim 8, wherein said friction control layers each are formed of nickel phosphate, nickel chromium, or chromium.
10. A manual hoist and traction machine according to claim 8 or 9, wherein the heat treatment temperature of said plated layer is set to an austenite transformation point temperature of the raw material of each of said brake holder, driving gear and holding plate, and said plated layer is diffused onto the surface of said each raw material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JPHEI.5-304,222 | 1993-12-03 | ||
| JP5304222A JP2601403B2 (en) | 1993-12-03 | 1993-12-03 | Manual chain block |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2136558A1 CA2136558A1 (en) | 1995-06-04 |
| CA2136558C true CA2136558C (en) | 1999-02-02 |
Family
ID=17930481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002136558A Expired - Fee Related CA2136558C (en) | 1993-12-03 | 1994-11-24 | Manual chain block |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2601403B2 (en) |
| AU (1) | AU670892B2 (en) |
| BE (1) | BE1008729A3 (en) |
| CA (1) | CA2136558C (en) |
| IT (1) | IT1275682B1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3065038B2 (en) | 1998-10-23 | 2000-07-12 | 象印チエンブロック株式会社 | Chain block |
| JP5827188B2 (en) * | 2012-07-30 | 2015-12-02 | 株式会社キトー | Chain block |
| CN113200472B (en) * | 2021-04-23 | 2022-09-20 | 浙江双鸟机械有限公司 | Friction transmission mechanism of electric chain hoist |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB691679A (en) * | 1900-01-01 | |||
| JPS59195193U (en) * | 1983-06-10 | 1984-12-25 | 象印チエンブロツク株式会社 | winding machine |
| JPH0774079B2 (en) * | 1991-10-31 | 1995-08-09 | 象印チエンブロック株式会社 | Mechanical brake for hoisting and towing machines |
| US5556078A (en) * | 1992-12-16 | 1996-09-17 | Elephant Chain Block Company Limited | Manual hoist and traction machine |
-
1993
- 1993-12-03 JP JP5304222A patent/JP2601403B2/en not_active Expired - Fee Related
-
1994
- 1994-11-16 AU AU78875/94A patent/AU670892B2/en not_active Ceased
- 1994-11-24 CA CA002136558A patent/CA2136558C/en not_active Expired - Fee Related
- 1994-12-01 BE BE9401091A patent/BE1008729A3/en not_active IP Right Cessation
- 1994-12-02 IT IT94MI002446A patent/IT1275682B1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| ITMI942446A1 (en) | 1996-06-02 |
| IT1275682B1 (en) | 1997-10-17 |
| AU670892B2 (en) | 1996-08-01 |
| ITMI942446A0 (en) | 1994-12-02 |
| CA2136558A1 (en) | 1995-06-04 |
| JP2601403B2 (en) | 1997-04-16 |
| BE1008729A3 (en) | 1996-07-02 |
| JPH07157290A (en) | 1995-06-20 |
| AU7887594A (en) | 1995-06-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |