Abstract:
The invention refers to a transport exchange truck for changing and alternating metallurgic vessels, particularly for steel mill converters. The truck is provided with an interior frame part arranged to rotate in the center of the exterior carriage frame with at least one piston--supportable on the mill floor--of a piston-cylinder unit to raise the exterior frame part carrying the undercarriages. The exterior frame part supports a lift table which can be raised or lowered by means of one or several piston-cylinder units. Each piston rod is connected with the lift table through at least one ball-and-socket joint whose joint housing is provided with articulated traction elements.

Description:
BACKGROUND AND DESCRIPTION OF THE INVENTION 
     Such vessel exchange trucks are used to transport metallurgic vessels with worn brick linings, for example, from the vessel stand to a brick lining stand, and back. To this end, it is necessary to detach the vessel from its rigging. The rigging in metallurgical plants consists of many different configured items including tilting frames, annular supports, pivot arms, casting devices, and the like. The transport of the vessel takes place on rails which cross. The carriage frame is lifted off the track at crossings, turned by 90°, and replaced on the other track. The present invention uses for this purpose pistons located in the center of the carriage frame for engaging the ground. While lift pistons, arranged at the carriage ends, are well known, the latter, however, require a long stroke as the carriage together with the vessel must be lifted up to operating position of the vessel. 
     Mounts for the metallurgical vessel vary greatly. The type of mounts on which the invention is based requires a lift table lifting the vessel into guides which have become untrue due to the heat of operation, or due to wear and tear. The lift table adapts to the inaccuracy by means of the mentioned inserted ball-and-socket joints, and/or traction elements articulated by means of ball-and-socket joints. 
     It has been disclosed in U.S. Pat. No. 3,718,265 to balance these inaccuracies by an individual adjustment of the lift table according to height and incline by arranging at each corner of the rectangular carriage frame lift devices in pairs, bearing Cardan or universal joints, at the ends of which the cylinders are attached, and by additional Cardan joints provided at the traction elements forming a connection with a bridge carrying the vessel. In this design, the traction elements may shift in the form of a parallelogram, whereby the lift devices maintain their perpendicular position. While the adaptability of the two spaced bridges forming the support for the lift table meets the requirements desired in operation, the system of the &#34;bridge&#34; leads to a relatively great structural width and structural length of the vessel exchange truck. The usual vessel exchange truck, therefore, necessitates a wide rail track which is abnormal. 
     The present invention provides vessel exchange trucks which are equipped with compact lift devices for a flexibly arranged lift table, as well as in view of the arrangement of the joint system for the lift table. The carriage is more narrow than before and runs on tracks of normal width. It is lighter and, with minor structural changes, may be used for small or large metallurgical vessels. 
     This problem is solved by the truck of the invention by first determining the plan outline of the vessels to be supported, and positioning the piston-cylinder units providing the lift for the lift table around the circumference of the plan outline. In addition, the guiding elements which provide traction for the lift table are hinged thereto and extend below the table a length equal to the piston-cylinder units. The guiding elements are hinged, in turn, at their lower ends to intermediate elements extending from the area of the support bearing surface of the vessels to be supported, and rigidly connected thereto. 
     Accordingly, the invention provides lift devices arranged closer than usual to the center of the vessel exchange truck. This arrangement in the center under the vessel ordinarily would lead to a very high structure. This problem is solved by the invention by means of the mentioned intermediate elements forming a stiff connection with the bearings, and to which the traction elements are hinged. This hinged arrangement extends into recessed areas of the carriage frame and is a decided saving in structural height. The use of traction elements whose cross section can receive great tractive or tensile forces, contributes to diminish the structural width. 
     The length of the traction elements is at the same time a way of increasing the adaptability of the support bearings to a warped vessel surface. In the sense of a greater adaptability, longer traction elements have the effect of increasing the horizontal displacement movement of the lift table. The vessel exchange truck of the invention is built in compact form in conjunction with the divided arrangement of the piston-cylinder units and traction elements and by using relatively small cross sections, as well as using the length of the traction elements. The compact construction provides a smaller width so that exchange truck can run on the normal track width of a conventional metallurgical plant rail track. Furthermore, due to the construction by the invention, there are considerable savings in weight and this construction is suitable for large as well as for small metallurgical vessels. 
     In further development of the basic concept of the invention, the intermediate elements consist of supports extending downward from the lift table, and are coordinated with the piston-cylinder units which are arranged spaced around the circumference of the lift table. Favorably, the lengths of the intermediate elements match approximately the lengths of the traction elements so that a considerable saving in structural height is achieved. Furthermore, the stress on the intermediate support element is manifested as buckling stress, and the stress on the traction element is manifested as tensile stress. Thus, the piston rods of the piston-cylinder units are only subject to tensile stress. Such piston-cylinder units are less expensive, and less heavy for longer piston travels. 
     The intermediate elements or links according to this invention are arranged so that the supports extending down from the lift table are of forked design. One piston-cylinder unit each is arranged within the space embraced by the fork. This arrangement also represents a saving in the truck&#39;s structural height. 
     Another modification of the positioning system of the invention is that the intermediate elements consist of yoke-shaped U-frames resting on the joint housings of the piston rods. This provides a two-way flexibility for the lift table support or the bearing points forming the lift table so that an even better adjustment to the contact points is reached when inserting the vessel. The invention presupposes that the lift table is elastically deformed under the load of the vessel which may amount to several hundred tons. This deformation may very easily be compensated for on account of the twofold flexibility. This adaptability to the insertion of the vessel into the bearing surface of the lift table is increased when sufficient space is left between the U-shaped frames of the intermediate elements and the related joint housing of the piston rod to allow play therebetween. The independence of individual bearing points can also be cancelled by providing a rigid interconnection between all U-frames by means of rods in the shape of a polygon. 
     For vessels whose rigging is provided at two opposing sides on the vessel circumference, it is advantageous if the piston-cylinder units are arranged with the intermediate elements at the longitudinal sides of the carriage forming entrance openings. 
     Another arrangement of the lift device and/or the guiding system of the invention is that the lift elements, flexibly attached to the intermediate elements, are hinged at their upper ends to a cross rail on a guide column displaceable within a guide housing and located centrally of the lift device. This arrangement also guarantees not only a narrow construction of the vessel exchange truck, but also the desired horizontal displacement of the lift table and/or its bearing points in an area of approximately 30-70 mm. The guide column, displaceable within a guide housing, may consist of a piston-cylinder unit. The structural height of the lift table is furthermore reduced when the guide column, which is displaceable within the guide housing, consists of a telescopic piston-cylinder unit. 
     According to further details of the invention the traction elements themselves may consist of piston-cylinder units with the cylinder housing and the piston rod each provided with a ball-and-socket joint. For the guiding system which, according to the type described, only results in a horizontal displacement motion of the lift table in the area of about 30 to 70 mm, and for such steering systems according to the invention for which a dual adaptation flexibility is considered advantageous, provision is made that the bearings supporting the metallurgical vessel consist of short-stroke piston-cylinder units arranged on the lift table and/or the U-frames coordinated with the piston-cylinder units. 
     Furthermore, an extremely low structural height of the vessel exchange truck is achieved by providing the interior frame portion with vertical recesses for the intermediate elements extending down from the lift table and/or piston-cylinder units. 
     Examples of the invention are shown on the drawings and explained as follows: 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIGS. 1-4 are each a vertical longitudinal sectional view of four different embodiments illustrating the vessel exchange truck of the invention; 
     FIG. 5 is a vertical longitudinal sectional view of a further embodiment illustrating the invention; 
     FIG. 6 is a plan view of the apparatus of FIG. 5 showing the arrangement of support mechanisms therein; 
     FIG. 7 is a vertical longitudinal sectional view of a further embodiment illustrating the invention; and 
     FIG. 8 is a plan view of the apparatus of FIG. 7 showing the arrangement of support mechanisms therein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The vessel exchange truck 1 according to the invention consists of the carriage frame 2 with an interior frame portion 2a, and exterior frame portion 2b, supporting itself on the undercarriages 3 and 4. The vessel exchange truck 1 runs on rails 5. These rails 5 have a track width of about 4,300 mm. Contrary to this the usual vessel exchange trucks run on rails with tracks having a width of about 6,200 mm. The interior frame portion 2a carries extendible pistons 6a, 6b, which may be supported on the surface 7 of the mill floor adjacent to the rails, whereby the interior frame portion 2a lifts the exterior frame portion 2b. In the raised position, the exterior frame portion 2b may be rotated into a new rail direction around the interior frame portion 2a by rotary bearings 8, by means of a rotary drive (not shown) which is of no consequence for an understanding of the invention. 
     The cylinder 10 for the piston 11 is supported in the hub 9 on the exterior frame part 2b. The cylinder 10 and the piston 11 form a piston-cylinder unit, and support the lift table 12 via traction elements 13. The traction elements 13 in FIG. 1 are three piston-cylinder units, whose individual cylinders are arranged on the base support plan of the embodiment in the corners of a triangle. There may, however, also be four or more traction elements 13. Generally, each piston-cylinder unit 10, 11 arranged eccentrically is coordinated with a traction element 13. Each piston-cylinder unit 10, 11 carries a ball-and-socket joint 14. The ball-and-socket joint 14 is located in most cases, according to FIGS. 1 through 4, at the traction elements 13. As shown in FIG. 2, each traction element 13 is provided with a ball-and-socket joint 14a at the upper end 13a and with a ball-and-socket joint 14b at the lower end 13b. The traction elements 13 may, as shown in FIG. 1, simultaneously be designed as a piston-cylinder unit with the piston 10a, and the cylinder 11a. In the typical design according to FIG. 1, the piston in the cylinder 10, as well as the piston 10a, in the cylinder 11a may be charged with a pressure fluid. 
     During the lifting process, the piston-cylinder 10, 11 are activated first, and the pistons 10a in the cylinders 11a are activated only after the highest possible lift or stroke of piston 11. The entire lift is advantageously extremely high, as may be seen in FIG. 1 from the lift position designated 15 shown in broken line, without relinquishing the effect of control of the steering system of the traction elements 13. 
     According to the embodiment of FIG. 2, the traction elements 13 are not provided with the dual function of traction rods or stabilizer bars and as piston-cylinder units simultaneously. Rather they are formed as traction rods alone, which are hinged to the cross rail 16 of the piston rod 11b by means of the ball-and-socket joints 14a, 14b. 
     The piston-cylinder unit 10, 11 in the embodiment shown in FIG. 2 is a telescopic piston-cylinder unit 10, 11, 17, whereby the piston 11 in the cylinder 17 acts at first as a first lift stage. In the second lift stage, the cylinder 17 forms the piston itself with its outer form in the cylinder 10. The piston 10 in the cylinder 11 of FIG. 3 represents the only lift drive in this embodiment. The traction elements 13 are designed as guide and stabilizer rods or tubes. 
     The embodiment of FIG. 4 provides a guide column 18 and a guide housing 19, which act solely as a vertical guide and which do not operate with a pressure fluid. The lift devices consist of the pistons 10a and the cylinders 11a acting simultaneously as traction elements 13. 
     All piston-cylinder units 10, 11 and/or 10a, 11a are arranged on an approximately circular base support plan extending to a width as shown at 20 in FIG. 5 which is roughly the diameter of vertically positioned vessel body 21. This measure, which is basically disadvantageous for the operating and structural height of the lift table 12, is partially compensated for by intermediate elements 22 (22a, 22b) extending from the lift table 12 downward. In a vessel exchange truck of extremely low construction, the intermediate elements 22 extend into recesses 23 (FIGS. 1-4) of the interior frame part 2a. The intermediate elements 22 are rigidly attached to the lift table 12. 
     The term &#34;lift table&#34; includes all the bearing supports and pedestals engaging and supporting the vessel during the exchange, and/or during transport thereof. Consequently, the &#34;lift table&#34; may include an annular bearing, such as one made up of an infinite number of bearing points as shown in FIGS. 1-4 or of four bearings as shown in FIGS. 5 and 6. However, there will be at least three bearings, as shown in FIGS. 7 and 8. In FIGS. 1 through 4, the bearings 24 consist of rings accommodating trestles 24a or short-stroke piston-cylinder units 24b. The short-stroke piston-cylinder units 24b permit additional unilateral lift movements, if the adaptation of the vessel 21 to greater inaccuracies of the vessel rigging requires such movements. 
     The intermediate elements 22 are formed as supports 22a, 22b, at whose lower ends the ball-and-socket joints 14b of the traction elements 13 are to be found. The supports 22, according to FIGS. 7 and 8, form forks 25. The piston-cylinder units 10a, 11a are arranged in the teeth 25a, 25b of forks 25 in a space-saving layout. 
     Diverging from the typical designs of FIG. 1 through 4, the exterior frame part 2b accommodates individually arranged piston-cylinder units 10, 11. Within the joint housing 14c, there is in each case another ball-and-socket joint 14, not shown, connected with the piston rod 10c of the piston-cylinder unit 10, 11. The connection includes a ring preventing the dropping out of the ball. The joint housing 14c rests on the ball. The traction elements 13 are hinged as described. The ends 13a and 13b make the connection, by means of the ball-and-socket joints 14a at the top and 14b at the bottom, to the intermediate element 22 consisting of the U-frame 22c. The U-frame 22c form a housing 26 open at the bottom. The housing 26 surrounds the joint housing 14c with clearance 27 (FIG. 5), so that there is a gap between the U-frame 22c and the joint housing 14c, permitting a displacement of the U-frames 22c. The displacement of the four U-frames 22c indicated in FIGS. 5 and 6 takes place at the same time, as all U-frames 22c are rigidly interconnected by means of the rods 28a, 28b, 28c, and 28d. In this way they form the adaptable lift table 12. 
     In FIG. 5, the sides to the left and to the right of the axis of symmetry 29 are shown in the raised position (left) and in the lowered position (right). In the arrangement of the piston-cylinder units (10a, 11c) according to FIG. 6 (as well as according to FIG. 8) entrance openings 30a and 30b are formed on the longitudinal truck sides 1a and 1b. 
     The lift table 12 may be annular as shown in FIGS. 7 and 8, as has already been mentioned, and may carry the intermediate elements 22 which are angular with legs extending toward the bottom. In this case, the extremely low construction of the vessel exchange truck 1 can be realized by means of the recesses 23, by providing the latter in the exterior frame part 2b. As is illustrated by FIGS. 7 and 8, the necessary height of the lift table 12 reaches approximately the height of the control room 31 (indicated in broken line). The structural height of the vessel exchange truck 1 is therefore considerably lower than that of the conventional vessel exchange truck where the piston-cylinder units protrude considerably beyond the control room cabin. 
     The vessel exchange truck is equipped with drive motors 32 arranged on the axles at the undercarriages 3 and 4. The lift table 12 is laterally provided with entrance openings 30a, and/or 30b and working platforms 33a and 33b. Instead of the piston-cylinder units 10, 11 and 10a, 11a, threaded spindle-threaded nut hoisting gears may be utilized as well as will be understood. Necessary reduction gears and the necessary electromotors or oil motors producing a rotary motion are firmly attached to the exterior carriage frame 2b, and if necessary by inserting universal joint (Cardan) shafts.