Abstract:
A taphole boring machine serving two tapholes includes a support structure, a mount and a suspension device of which the mount is secured on the supporting structure and the suspension device has a tilting device for the mount with the suspension device further including a mechanism within a frame, a first drive and two connection points with a mechanism designed in such a way that a positively guided translation of two connection points in relation to the frame can be produced by a drive pulse of the first drive so that a connecting line through the two connection points remains parallel with itself during such movement.

Description:
The invention relates to a taphole drilling machine, in particular a taphole drilling machine to serve several tapholes on a shaft furnace. 
     BACKGROUND OF THE INVENTION 
     Modern blast furnaces usually have several tapholes. Each of these taholes is served by its own drilling machine. As an efficient taphole drilling machine is relatively expensive, it would, of course, be interesting for cost reasons to develop a machine which can be used for several adjacent tapholes at the same time. 
     A taphole drilling machine of this type was already described in DE-A-19 62 953 in 1967. This machine comprises a fixed bracket and an arm, the first end of which can be swivelled about a first axis and is mounted in the fixed bracket. The arm, which can be swivelled by a drive from a first operating position in front of the first taphole into a second operating position in front of the second taphole, carries at its free end a vertical pivot on which a mount is mounted. A control rod is connected by swivel joints to a fixed lever arm on the bracket and to a crank firmly seated on the pivot. These form a four-link swivel joint mechanism, in which a swivelling movement of the arm about the first axis produces a swivelling movement of the mount about the second axis. To allow adaptation of the angle of inclination of the drilling axis to the respective taphole, the mount is connected by a horizontal swivelling joint to vertical pivots, and a tilting cylinder is arranged between the mount and a flange secured rigidly to the vertical pivot. To adapt the height of the drilling axis to the respective taphole on the other hand it is proposed that the mount be brought to different points of proximity to the taphole, i.e. to limit the swivelling movement of the arm. However, the result is that only very small differences in height can be compensated, because firstly the swivelling movement of the arm determines the final position of the mount and, secondly, the distance between the mount end and the taphole should preferably be identical. 
     A rock drilling machine, as used in mines, for example, is known from U.S. Pat. No. 3,349,975. This rock drilling machine has a parallelogram mechanism with a frame, three links and four joints, which permits parallel displacement of a drill mount by means of a first pressure cylinder. A second pressure cylinder is connected between the parallelogram mechanism and the drill mount and permits tilting of the drill mount. An additional rotary motor permits 360° rotation of the parallelogram mechanism about a horizontal axis. The aim of the device is to permit universal alignment of the drill mount via a hydraulic control system in relation to a horizontal axis, so that the rock drilling machine can drill several holes without having to be repositioned. 
     A taphole plugging machine, in which a mud gun is suspended by two articulated supporting links from a supporting structure, is known from FR-A-2 604 511. A pressure cylinder permits swivelling of the mud gun in a vertical plane and thus firm contact with its nozzle against the taphole. One of the two supporting links is longitudinally adjustable, so that the inclination of the mud gun can be adapted to the inclination of a taphole. 
     There is a need for a taphole drilling machine which permits variation in the height and inclination of the drilling machine to serve two tapholes, which can approach two tapholes with a different height and inclination in an optimum manner. 
     SUMMARY OF THE INVENTION 
     In the taphole drilling machine according to the invention the suspension device has a mechanism with a frame, a first drive and two connection points. The mechanism is designed in such a way that a positively guided translation of the two connection points in relation to the frame can be produced by a drive pulse of the first drive in such a way that a connecting line through the two connection points remains parallel with itself during this movement. A tilting device is provided with a connection joint, a supporting joint and a second drive and is designed in such a way that the distance between the connection joint and the supporting joint is adjustable by a drive pulse of the second drive. It is mounted via the connection joint on a first of the two connection points of the mechanism. In a first embodiment of the taphole drilling machine according to the invention the tilting device is connected via its supporting joint to the mount, the second connection point of the mechanism by a supporting joint to the mount and the frame to the supporting structure. In a second embodiment of the taphole drilling machine according to the invention the tilting device is connected via its supporting joint to the supporting structure, the second connection point of the mechanism by a supporting joint to the supporting structure and the mount to the frame. In both forms of construction the height of the mount can be adjusted via a single drive without changing the inclination of the mount. 
     According to the invention the mechanism is driven by a first pressure cylinder, which has a stroke limiting device with two independently adjustable strokes. The drill mount, which is raised into a rest position when approaching a taphole, can thus be lowered to the level of two tapholes at different heights in the operating position. The tilting device is driven by a second pressure cylinder, which likewise has a stroke limiting device with two independently adjustable strokes, so that the drill mount, which is advantageously in a horizontal rest position when approaching a taphole, can be adapted to the inclination of two tapholes with different inclination in the operating position. 
     In a preferred simple and space-saving embodiment the mechanism comprises a frame and three links connected by four swivel joints A, B, C and D. In this mechanism the distance between joint A and joint D corresponds to the distance between joint B and joint C, the distance between joint A and joint B to the distance between joint D and joint C and the distance between joint A and the supporting joint E of the mechanism to the distance between joint B and the supporting joint F of the tilting device. 
     Alternatively the mechanism could also have two links arranged in an X-shape, which are connected in their centre by an additional swivel joint. The frame and a third link are then each connected by a simple swivel joint and a combined turning and sliding joint to the ends of the two links in an X-shaped arrangement, the geometrical arrangement of these swivel joints advantageously corresponding to the geometrical arrangement of the corner points of a rectangle. This form of construction has the advantage that a pure vertical displacement of the mount can be achieved without horizontal movement components. However, it is far more complicated in its construction as a result of the turning and sliding joint and requires substantially more space. 
     The mechanism is advantageously driven by a pressure cylinder but could, of course, also comprise a rotary drive of one of the links. The pressure cylinder advantageously has a stroke limiting device with two independently adjustable strokes, so that the mount, which is advantageously raised to a rest position when approaching a taphole, can be lowered to the level of two tapholes of different height in the operating position. 
     The tilting device is advantageously designed as a pantograph. The second pressure cylinder can be mounted particularly easily on this pantograph. By opening and closing the pantograph the second pressure cylinder enables the distance between the connection joint and the supporting joint of the tilting device to be adjusted. The pressure cylinder of the tilting device also advantageously has a stroke limiting device with two independently adjustable strokes, so that the mount, which is advantageously in a horizontal rest position when approaching a taphole, can be adapted to the inclination of two tapholes of different inclination in the operating position. 
     The foregoing and additional objects and features of the invention will become apparent from the following description in which preferred embodiments have been set forth in detail in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial view of a taphole drilling machine according to the invention in a rest position; 
     FIG. 2 is a partial view of the taphole drilling machine in FIG. 1 in an operating position; 
     FIG. 3 is a partial view of the taphole drilling machine in FIG. 1 in a third position; 
     FIG. 4 is a longitudinal section through an advantageous embodiment of a pressure cylinder for a suspension device of a taphole drilling machine according to the invention, the main piston assuming a first end position; 
     FIG. 5 is a longitudinal section as in FIG. 4, the main piston assuming a second end position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A mount  10  (shown only in section) and a suspension device  12 , by means of which the mount  10  is mounted on a supporting structure  14 , can be seen in FIGS. 1 to  3 . For the sake of simplicity the supporting structure  14  is shown only schematically in the figures. Such a supporting structure may comprise, for example, a rotatable arm, on the free end of which the suspension device  12  is rotatable about an axis  16  (indicated by a broken line). An advantageous embodiment of such a supporting structure  14  with an arm is described, for example, in the patent applications of the applicant LU 88799 dated Aug. 1, 1996 and LU 88782 dated Jun. 28, 1996, the entire disclosure of which is included by reference in the present application. In an alternative embodiment the supporting structure  14  could, however, likewise comprise a car guided by rails, which carries the suspension device  12 . 
     The suspension device  12  is described in more detail below with the aid of FIG.  2 . It comprises a flat, four-link mechanism with four swivel joints. A first link  18  is designed as a mechanism frame and mounted on the supporting structure  14 . This first link  18  has two legs  20  and  22 . The first leg  20  is connected via a joint A to a second link  24 . The latter is L-shaped with a first arm  26  and a second arm  28 , the joint A being arranged at the point of intersection of the two  25  arms  26  and  28 . The second leg  22  of the first link  18  is connected via a joint B to a third link  30 . The latter is likewise L-shaped with a first arm  32  and a second arm  34 , the joint B being arranged at the point of intersection of the two arms  32  and  34 . A fourth link  36 , which is designed, for example, as a rod, is connected via a joint D to the second arm  28  of the second link  24  and via a joint C to the second arm  34  of the third link  30 . The four links  18 ,  24 ,  30  and  36  designed in such a way that the distance between joint A and joint D corresponds to the distance between joint B and joint C, and the distance between joint A and joint B to the distance between joint D and joint C. The mechanism has two connection points E′ and F′. The connection point E′ is located on the first arm  26  of the second link  24  and a swivel joint E connecting the mechanism to the mount  10  is assigned to it. The connection point F′ is located on the first arm  32  of the third link  30 . 
     The drive of the four-link mechanism described above is formed by a pressure cylinder  38 . The latter is pivoted with its first end on the frame  18  and with its second end on the second arm of the third link  30  in the mechanism. In FIG. 2 the piston rod  40  of the pressure cylinder  38  is retracted. By contrast the piston rod  40  of pressure cylinder  38  is extended in FIG.  1 . The extension of piston rod  40  caused rotation of the third link  30  about the joint B. This rotation was transmitted to the second link  24  via the fourth link  36 . By virtue of the above-mentioned arrangement of joints A, B, C and D at the corner points of a parallelogram the angle of rotation of the second link  24  about the joint A corresponds exactly to the angle of rotation of the third link  30  about the joint B. 
     A tilting device  42  is connected via a connection joint F at the connection point F′to the first arm  32  of the third link  30  and via a supporting joint G to the mount  10 . The distance between joint A and the supporting joint E corresponds to the distance between joint B and the connection joint F, with the result that a drive pulse of the first pressure cylinder  38  produces a positively guided translation of the supporting joint E and the connection joint F in relation to the frame  18 , so that a hypothetical connecting line through the two connection points E′ and F′ remains parallel with itself during this movement. It follows that the mount  10  can likewise be raised and lowered parallel with itself by the pressure cylinder  38 . The height of the drilling axis can thus be fixed without changing the inclination of the mount  10  and thus the inclination of the drilling axis. It should be particularly emphasized that the mechanism described above is of extremely compact construction and simultaneously introduces forces in the longitudinal direction of the mount  10  relatively rigidly into the supporting structure  14 . The tilting device  42  is designed in such a way that the distance between connection joint F and supporting joint G is adjustable. In the form of construction shown it comprises, for example, a two-link pantograph  44  with a joint H. A pressure cylinder  50  is pivoted at one end of the first link  46  and at the other end on the second link  48  of the pantograph  44  and thus enables the distance between joint F and joint G to be increased and reduced by opening and closing the pantograph  44 . The pressure cylinder  50  could, of course, also be connected directly, i.e. without pantograph  44 , via a connection joint F to the first arm  32  of the third link  30  and via a supporting joint G to the mount  10 . However, the pressure cylinder  50  can be incorporated mechanically far more advantageously into the suspension device  12  by means of the pantograph  44 . Comparison of FIG. 2 with FIG. 3 reveals that the distance between joints F and G was shortened by retraction of the piston rod of the pressure cylinder  50 . Consequently the supporting joint G was raised in relation to the supporting joint E, so that the mount  10  is inclined forwards. 
     It should be noted that the same result is achieved if the mechanism frame is formed e.g. by the mount and the two supporting joints E and G are connected to the supporting structure. 
     An advantageous embodiment of the two pressure cylinders  38  and  50  is described with the aid of FIGS. 4 and 5. This is a pressure cylinder  100  with a main piston  104 , which is fitted into a cylinder chamber  102 , and its stroke in the cylinder chamber  102  is adjustable via an attached stroke limiting device. The latter comprises an auxiliary piston  106  with a piston extension  108 , which is sealingly introduced into the cylinder chamber  102 . The auxiliary piston  106  seals a pressure chamber  110 , on which a pressure medium can act. A connection piece  112  is sealingly led out of the pressure chamber  110  and has a thread  114  with two nuts  116  and  118  screwed on. In FIG. 4 the pressure chamber  110  is pressureless. The main piston  104  rests on the piston extension  108  and can force the latter back as far as the stop of nut  116  on a clamp  120 . It is clear that in this position the piston extension  108  projects only slightly into the cylinder chamber  102 , so that the main piston stroke corresponds to almost the total length of the cylinder chamber  102 . 
     In FIG. 5 the pressure chamber  110  is exposed to the same pressure as the rear section of the cylinder chamber  102 . The piston extension  108  now projects substantially into the cylinder chamber  102  and limits the stroke of the main piston  104 . As the cross-section of the pressure chamber  110  sealed by the auxiliary piston  106  is greater than the cross-section of cylinder chamber  102  sealed by the main piston  104 , the main piston  104  can no longer force back the piston extension  108 . The second nut  118  enables the depth of penetration of the piston extension  108  into the cylinder chamber  102  to be limited.