Claims
- 1. In continuous casting equipment having a path of transport of castings which is defined by a plurality of roll segments and has a curved section and a horizontal section, an apparatus for hoisting an optional roll segment comprising:
- a trolley provided movably above the horizontal section,
- a pair of pivotal guide rods pivotally supported by the trolley,
- a pair of fixed guide rods arranged on the opposite sides of each of the roll segments defining the curved section,
- a pair of fixed circular arc rails extending along the paths of movement of the free ends of the pivotal guide rods,
- a truck having a pair of front wheels and pair of rear wheels movable on the rails;
- means for engaging the truck with the pivotal guide rods,
- means for reciprocating the truck along the rails together with the pivotal guide rods in engagement with the truck,
- means for locking the pivotal guide rods in a position where the pivotal guide rods are continuous with a selected pair of fixed guide rods, and
- means for hoisting a corresponding roll segment along said selected pair of fixed guide rods to the pivotal guide rods when the pivotal guide rods are made continuous with the fixed guide rods, wherein:
- the locking means is provided in the form of pairs of recesses formed in the circular arc rails in corresponding relation to the pairs of fixed guide rods, the rear wheels of the truck being positionable in each pair of recesses to lock the truck to the rails so that the pivotal guide rods, when in engagement with the truck, are indirectly locked to the rails in alignment with a corresponding pair of fixed guide rods, and
- the engaging means comprises a pair of rollers mounted on the free ends of the pivotal guide rods individually, a pair of passage cutouts formed in the rear end of the truck for permitting the rollers to pass therethrough individually, and a pair of elongated engaging grooves formed in the rear end of the truck in communication with the respective cutouts for the rollers to fit in slightly when the truck is in a state for movement but deeply when the truck is locked to the rails.
- 2. An apparatus as defined in claim 1 wherein the circular arc rails have a center of curvature positioned above the center of curvature of the curved section of the transport path.
- 3. An apparatus as defined in claim 1 wherein each of the elongated engaging grooves extends along a circular arc centered about the front wheel of the truck.
- 4. An apparatus as defined in claim 1 which further comprises holding means for preventing the rear wheels of the truck from falling into the recesses.
- 5. An apparatus as defined in claim 4 wherein the holding means comprises a pair of engaging members provided on the rear end of the truck, and a pair of cylinder assemblies mounted on the pivotal guide rods individually and each having a hook engageable with the corresponding engaging member.
Parent Case Info
The present invention relates to an apparatus for hoisting a support frame having a pair of casting guide rolls supported thereon (which frame will hereinafter be referred to as a "roll segment") in continuous casting equipment, and more particularly to an apparatus which is capable of hoisting any one of roll segments defining a path of transport of castings even when the transport path comprises a curved section and a horizontal section.
Casting guide rolls for use in continuous casting equipment are subject to wear or thermal cracking due to contact with castings over a prolonged period of time and must therefore be repaired or replaced occasionally. In such a case, the roll segment concerned is removed from the path of transport of castings by hoisting. Various apparatus have heretofore been proposed for this purpose.
Published unexamined Japanese patent application No. 55-117547 discloses a roll segment hoisting apparatus for use in continuous casting equipment wherein a path of transport of castings is defined by a plurality of roll segments and has a curved section and a horizontal section. The disclosed apparatus comprises a crane disposed movably above the horizontal section, a pair of pivotal guide rods pivotally movably supported by the crane, a pair of fixed guide rods arranged on the opposite sides of each of the roll segments defining the curved section, a pair of fixed circular arc rails extending along the paths of movement of the free ends of the pivotal guide rods, a truck having a pair of front wheels and a pair of rear wheels movable on the rails, means for engaging the truck with the pivotal guide rods, means for reciprocating along the rails the truck in engagement with the pivotal guide rods, means for locking the pivotal guide rods in a position where the guide rods are continuous with the pair of fixed guide rods individually, and means for hoisting the corresponding roll segment along the fixed guide rods to the pivotal guide rods when the pivotal guide rods are made continuous with the fixed guide rods. The locking means comprises cylinder assemblies mounted on the pivotal guide rods and a pair of engaging members each projecting from each of the circular arc rails at a location corresponding to each of the fixed guide rods and engageable with the piston rod of the cylinder assembly when the piston rod is extended.
The above apparatus, although installed singly, is adapted to hoist any roll segment from either of the curved section and horizontal section of the casting transport path, and in this sense, the apparatus is much more advantageous in respect of operability, cost and installation space than the usual arrangement wherein two separate apparatus are provided for the curved section and the horizontal section individually. However, the locking means for the pivotal guide rods of the foregoing construction has the following drawbacks.
The object of the present invention is to overcome these problems and to provide a hoisting apparatus which operates reliably with stability.
To fulfill this object, the invention provides a roll segment hoisting apparatus for use in continuous casting equipment having a path of transport of castings which is defined by a plurality of roll segments and has a curved section and a horizontal section. The apparatus comprises a trolley provided movably above the horizontal section, a pair of pivotal guide rods pivotably supported by the trolley, a pair of fixed guide rods arranged on the opposite sides of each of the roll segments defining the curved section, a pair of fixed circular arc rails extending along the paths of movement of the free ends of the pivotal guide rods, a truck having a pair of front wheels and a pair of rear wheels movable on the rails, means for engaging the truck with the pivotal guide rods, means for reciprocating the truck along the rails together with the pivotal guide rods in engagement with the truck, means for locking the pivotal guide rods in a position where the guide rods are continuous with the pair of fixed guide rods individually, and means for hoisting the corresponding roll segment along the fixed guide rods to the pivotal guide rods when the pivotal guide rods are made continuous with the fixed guide rods, the locking means being in the form of pairs of cavities formed in suitable portions of the circular arc rails, the rear wheels of the truck being positionable in each of the pairs of cavities to lock the truck to the rails, whereby the pivotal guide rods when in engagement with the truck are indirectly locked to the rails.
With the locking means described above, the engagement of the rear wheels in the pair of cavities automatically determines the position in which the pivotal guide rods are to be locked, so that the guide rods are positionable properly without necessitating the cumbersome procedure needed for the conventional cylinder-engaging member arrangement. Further if the truck is forcibly pulled up while the locking means is in operation, i.e. while the rear wheels are positioned in the cavities, the rear wheels will move out of the cavities. Whereas the conventional locking means is likely to suffer damage due to a malfunction, this eliminates such a likelihood.
According to a preferred embodiment of the invention, the center of curvature of the circular arc rails is positioned above the center of curvature of the curved section of the casting transport path.
When the locking means is provided as pairs of cavities formed in the circular arc rails, it is intended to cause the rear wheels of the truck to fall into the pair of cavities under gravity, so that there is the need to increase the component of gravity on the truck acting toward the bottom of the cavity in order to assure a locked state, but this component of gravity invariably decreases upward along the rail which is in the form of an arc. With the above embodiment, the center of curvature of the rail is positioned above the center of curvature of the curved section of the transport path to render the inclination of the upper portion of the rail smaller than otherwise and thereby increase the component of gravity acting toward the bottom of the cavity to the greatest possible extent.
According to another embodiment of the invention, the hoisting apparatus is provided with holding means for preventing the rear wheels of the truck from falling into some of the cavities.
If the rear wheels of the truck are allowed to fall into every pair of the cavities, it is impossible to operate the apparatus. The rear wheel portion of the truck is therefore usually held raised by the holding means to cause the rear wheels to fall only into the desired pair of cavities.
US Referenced Citations (1)
| Number |
Name |
Date |
Kind |
|
4223715 |
Streubel |
Sep 1980 |
|
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 55-117547 |
Sep 1980 |
JPX |
Patent Grant
4440211
