Patent Grant
9181071
1. Field of Invention
The present invention relates to a hoist such as an electric chain hoist and, more specifically, to a hoist equipped with a power-off type electromagnetic brake allowing manual lowering of a load at the time of a power failure or the like.
2. Description of Related Art
Conventionally, as an electric chain hoist allowing manual lowering at the time of a power failure, there has been well-known an electric chain hoist which is provided with a brake releasing wedge member to be driven into a gap portion between a brake base of an electromagnetic brake portion and an armature and which has, in a surrounding wall portion of a brake casing to which the electromagnetic brake portion is mounted, a driving-in hole into which the wedge member is to be inserted, wherein, at the time of a power failure or the like, the brake releasing wedge member is driven into the gap portion between the brake base and the armature to release the electromagnetic brake, thus allowing manual lowering (JP-1-85397 A (Utility Model)).
3. Technical Problems
In the above-mentioned prior-art technique, the brake releasing wedge member is inserted into a driving-in radial hole provided in the wall portion of the brake casing, and the wedge member is driven into the gap portion between the brake base and the armature by a striking tool such as a hammer to enlarge the gap portion between the brake base and the armature, thereby releasing the electromagnetic brake portion and placing the brake disk and the armature in a non-contact state; and, in this state, load lowering is manually performed by a handle mounted to an end portion of a motor rotation shaft; after the wedge member has been driven into the gap portion between the brake base and the armature, the brake remains released, so that it is impossible to adjust the brake force at the time of lowering the load; thus, it is impossible to adjust the load lowering speed; further, the wedge member is inserted into the driving-in hole provided in the brake casing, and is driven into the gap between the brake base and the armature by a striking tool such as a hammer, so that, when the wedge member becomes loose, the brake is engaged, making it difficult to smoothly perform the operation of lowering the load; further, the wedge member will be detached from the driving-in hole to be dropped.
The present invention has been made with a view toward solving the above problem; the invention is directed to a hoist equipped with a power-off type electromagnetic brake, wherein, at positions corresponding to an upper portion and a lower portion of a brake disk of an electromagnetic brake cover surrounding the electromagnetic brake, there are respectively provided upper and lower insertion openings for first and second operation levers to be vertically inserted between an armature and a pressure-receiving plate of the electromagnetic brake, wherein the first operation lever has an insertion portion to be fitted from above into the upper insertion opening to be inserted between the armature and the pressure-receiving plate, a lever portion horizontally bent from the insertion portion, and a connection portion downwardly bent from the lever portion to be connected with the second operation lever, and wherein the second operation lever has an insertion portion fitted from below into the lower insertion opening to be inserted between the armature and the pressure-receiving plate, and an operation portion horizontally bent from the insertion portion.
According to another aspect of the invention, a detachment prevention member configured to maintain the connection with the first operation lever is provided at an end portion of the operation portion of the second operation lever.
According to still another aspect of the invention, a detachable sealing member is provided at the insertion opening of the electromagnetic brake cover.
According to yet another aspect of the invention, there is provided in the outer periphery of the electromagnetic brake cover a fan cover surrounding the electromagnetic brake cover, and insertion openings are respectively provided at a position above the upper insertion opening and at a position below the lower insertion opening of the brake cover of the fan cover, with a seal being attached to the insertion openings.
According to the present invention, there is provided a brake releasing device in which a first operation lever and a second operation lever are connected, with the first operation lever being inserted into the brake disk from above the electromagnetic brake cover, so that there is no need to provide a means for mounting operation means such as a bolt or a fulcrum shaft, making it possible to provide a brake releasing device of a very simple construction.
Further, the force applied to the operation lever is adjusted by the operator, whereby it is possible to make the damping force of the brake variable, making it possible to lower the load at an arbitrary lowering speed.
Further, when the lowering speed is too high, the brake is caused to operate by releasing the second operation lever, so that it is possible to provide a safe hoist capable of preventing dropping of the load.
Further, even when the operator releases the operation lever, the insertion portion of the U-shaped first operation lever remains caught by the brake device main body; further, the second operation lever has a detachment prevention member so that it may not be detached from the connection portion of the first operation lever, so that it is possible to prevent detachment of the second operation lever fitted from below into the electromagnetic brake cover, making it possible to provide a safe brake device.
a) is a diagram illustrating the overall structure of the electromagnetic brake portion and
a) is a diagram illustrating the overall structure of an operation lever according to the present invention and
The chain hoist main body 7 has a well-known load sheave (not shown) and a drive shaft extending through the load sheave; one end of the drive shaft is connected to a motor shaft 5 of the motor 13, and the other end thereof extends through the load sheave, with the end-portion outer periphery thereof being in mesh with a large-diameter driven gear of a speed reduction gear mechanism 6. The large-diameter driven gear drives the load sheave via a small-diameter driven gear and a load gear in mesh with the above-mentioned gear, raising and lowering a load chain 8 through winding.
The motor 13 is equipped with a stator 14 and a rotor 15, and the stator 14 is fixed in position within the motor frame 2 through fit-engagement. The rotor 15 is fixed to the motor shaft 5 rotatably supported via a bearing 31, and is arranged so as to extend through the central portion of the stator 14.
As described above, when, in the electric chain hoist, the rotor 15 rotates, and the motor shaft 5 rotates, the rotation of the motor shaft 5 is transmitted to the drive shaft of the chain hoist main body 7, and is transmitted to the load sheave via the speed reduction gear mechanism 6 in mesh with a gear formed at an end portion of the drive shaft, winding up and down a load chain 10. In the drawing, numeral 9 indicates an upper hook, and numeral 10 indicates a lower hook.
Next, an electromagnetic brake device according to an embodiment of the present invention will be described with reference to
The electromagnetic brake 16 is composed of an electromagnet 19, a brake disk 20 connected to the motor shaft 5 by virtue of a brake disk boss 23, friction members 20a and 20b firmly attached to both sides of the brake disk 20, a pressure-receiving plate 21 held in press contact with one friction member 20a, and an armature 22 held in press contact with the other friction member 20b. The armature 22 is constantly urged toward the brake disk 20 side by a brake spring 24 shown in
Next, an operation lever according to the present embodiment will be described. Numeral 25 indicates an operation lever, which is composed of a first operation lever 26 and a second operation lever 27; the first operation lever 26 has an insertion portion 26a inserted between the pressure-receiving plate 21 and the armature 22 from above a brake cover 18 of the electromagnetic brake, a lever portion 26b bent horizontally from the insertion portion 26a in an L-shape, and a connection portion 26c which is bent vertically from the lever portion 26b in an L-shape and to which a second operation lever 27 described below is connected. Numeral 26d indicates a connection hole into which the second operation lever 27 is fitted. The second operation lever 27 has an insertion portion 27a inserted between the pressure-receiving plate 21 and the armature 22 from below the brake cover 18 of the electromagnetic brake, and an operation portion 27b bent horizontally from the insertion portion 27a in an L-shape and fitted into the connection hole 26d of the first operation lever 26 to perform the operation of releasing the brake. Numeral 28 indicates a detachment prevention member provided at an end portion of the second operation lever 27 and configured to prevent detachment of the operation portion 27b from the connection hole 26d.
In the present embodiment, at positions corresponding to the upper portion and the lower portion of the brake disk 20 of the electromagnetic brake cover 18, there are respectively provided insertion openings 18a and 18b for the insertion of the first operation lever 26 and the second operation lever 27 at symmetrical positions on both sides of the rotation shaft of the brake disk 20 (which is coaxial with the motor shaft); a fan cover 3 is provided with insertion openings 3a and 3b for the first operation lever 26 and the second operation lever 27 at positions respectively corresponding to the upper and lower insertion openings 18a and 18b of the electromagnetic brake cover 18. Numeral 29 indicates rubber plugs stopping the insertion openings 18a and 18b of the electromagnetic brake cover 18, and numeral 30 indicates seals or plates stopping the insertion openings 3a and 3b of the fan cover 3.
Next, the procedures for attaching the operation lever 25 to the electromagnetic brake will be described. As shown in
Next, as shown in
The operation of the electromagnetic brake employing the operation lever 25 will be described. As shown in
In the present embodiment, at the time of brake releasing operation, the armature 22 is simultaneously separated from the brake disk 20 by the first operation lever 26 from above and separated from the brake disk 20 by the second operation lever 27 from below, whereby the brake disk 20 is set free, and the motor shaft 5 is released. Further, by adjusting the force with which the pressing-down by the second operation lever 27 is performed, it is possible to adjust the braking force of the brake, making it possible to safely lower the load. Further, even if the operator erroneously releases the second lever 27, the brake operates instantaneously to retain the suspension load. Further, the second operation lever 27 is connected to and retained by the first operation lever 26, and the distal end of the insertion portion 26a of the first operation lever 26 is inserted between the pressure-receiving plate 21 and the armature 22; and, the insertion portion 26a is retained by the side walls of the insertion opening 18a of the electromagnetic brake cover 18 and of the insertion opening 3a of the fan cover 3, and the retaining portion 26b is brought into contact with the upper surface of the fan cover 3 to be regulated in tilting, so that even if the operator releases the second operation lever 27, it is possible to prevent the operation lever 25 from dropping.
b) shows a mode in which a cutout 26e is provided at the distal end of the insertion portion 26a of the first operation lever 26. When the bolts 22 and the spacers 33 are arranged on the upper portion of the brake disk in the state in which the electric chain hoist is suspension-installed, the cutout 26e is provided in order to avoid them. The cutout 26e may be provided at the center in the width direction of the insertion portion 26a. The configurations of the first operation lever 26 and of the second operation lever 27 are not restricted to those of the above-described embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-065930 | Mar 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/057187 | 3/21/2012 | WO | 00 | 12/4/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/128286 | 9/27/2012 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 1768295 | Rogers | Jun 1930 | A |
| 1945712 | Wadd | Feb 1934 | A |
| 2233798 | Robins | Mar 1941 | A |
| 2247795 | Whitcomb et al. | Jul 1941 | A |
| 2365141 | Sully | Dec 1944 | A |
| 2433488 | Schultz | Dec 1947 | A |
| 2526092 | Snyder | Oct 1950 | A |
| 2590610 | Grosch | Mar 1952 | A |
| 2695086 | Parker | Nov 1954 | A |
| 3027985 | Klsing, Jr. | Apr 1962 | A |
| 3042375 | Fahey et al. | Jul 1962 | A |
| 3090601 | Robins et al. | May 1963 | A |
| 3125200 | Kaman | Mar 1964 | A |
| 3286989 | Bangerter et al. | Nov 1966 | A |
| 3453902 | Belle | Jul 1969 | A |
| 3668944 | Natschke | Jun 1972 | A |
| 3769480 | Lee | Oct 1973 | A |
| 3784165 | Pruitt | Jan 1974 | A |
| 3923287 | Weseloh et al. | Dec 1975 | A |
| 4065102 | Johnson et al. | Dec 1977 | A |
| 4162059 | Fletchall | Jul 1979 | A |
| 4254941 | Tanson | Mar 1981 | A |
| 4358088 | House et al. | Nov 1982 | A |
| 4444375 | Horn | Apr 1984 | A |
| 4552340 | Sheppard | Nov 1985 | A |
| 4576363 | Pancook | Mar 1986 | A |
| 5088694 | Nishimura | Feb 1992 | A |
| 5142847 | Watanabe et al. | Sep 1992 | A |
| 5186286 | Lindberg | Feb 1993 | A |
| 5305989 | Nishi et al. | Apr 1994 | A |
| 5368138 | Kuivamaki | Nov 1994 | A |
| 5573091 | Hung | Nov 1996 | A |
| 6427982 | Sugimachi | Aug 2002 | B1 |
| 7111803 | Mott et al. | Sep 2006 | B2 |
| 7866633 | Weiss et al. | Jan 2011 | B2 |
| 20030098452 | Nakamura et al. | May 2003 | A1 |
| 20050247508 | Gilliland et al. | Nov 2005 | A1 |
| 20060017047 | Calver | Jan 2006 | A1 |
| 20080224110 | Starks et al. | Sep 2008 | A1 |
| 20090121204 | Guyard | May 2009 | A1 |
| 20090309082 | Webb et al. | Dec 2009 | A1 |
| 20100127818 | Ishikawa et al. | May 2010 | A1 |
| 20110236514 | Fujieda et al. | Sep 2011 | A1 |
| 20120187355 | Mehrkens | Jul 2012 | A1 |
| 20140262593 | Castaneda et al. | Sep 2014 | A1 |
| Number | Date | Country |
|---|---|---|
| 1-85397 | Jun 1989 | JP |
| 6-44376 | Jun 1994 | JP |
| 2001-146933 | May 2001 | JP |
| 2002-51498 | Feb 2002 | JP |
| 2002-136048 | May 2002 | JP |
| 2002-344150 | Nov 2002 | JP |
| 2008114608 | Sep 2008 | WO |
| Entry |
|---|
| International Search Report issued Jun. 19, 2012 in corresponding International Application No. PCT/JP2012/057187. |
| Number | Date | Country | |
|---|---|---|---|
| 20140124720 A1 | May 2014 | US |
