EP0064645A1 - Guiding and positioning mechanism for the drill hammer of the taphole in a shaft furnace, and drilling device provided with this mechanism - Google Patents

Abstract

In a machine designed for a process according to which the opening and closing of the casting hole comprise an operation of extracting and an operation of replacing a tapping rod (16) respectively, the frame (20) of the machine must be aligned with the rod (16) in order to be capable of grasping the latter and, for this purpose, a claw (22) is provided, attached to the front of the frame (30) and capable, by pivoting of one (24) of its claws, of seizing and guiding the tapping rod (16). <IMAGE>

Description

The present invention relates to a device for centering and guiding a rod for drilling the tap hole of a shaft furnace suitable for a method according to which the opening and closing of the tap hole respectively comprise an extraction operation and an operation to replace the drilling rod which is abandoned in the taphole between two successive castings, and designed to be mounted on the front end of the mount of a taphole drilling machine equipped a device for gripping the end of the piercing rod which can slide along the mounting of the machine. The in- ven _t ion also relates to a drilling machine equipped with a tap hole of such a centering and guiding device.

This relatively recent method for opening the tap hole by means of a drilling rod which is abandoned in the tap hole between two successive castings is attracting growing interest at the expense of conventional methods consisting in drilling the tap holes using a drill bit. drilling. For more details concerning this process and its advantages, as well as for the necessary equipment, reference may be made to Luxembourg patent No 82.943.

This patent also explains the problems linked to the use, for the implementation of this new process, of machines designed for the conventional drilling processes or to the design of machines suitable for the implementation of the two processes, namely the process either the drilling process mentioned in the preamble.

These problems result from the need for alignment between the piercing rod and the gripping device thereof, as well as from the need to "thread" the piercing rods through a guide and support device during the approach movement from the lookout to the operative position.

However, there are two factors to consider tion and which generally result in these conditions not being met. Indeed, it may happen that the piercing rod after being replaced in the tap hole, in the not yet hardened plugging mass bends or bends slightly under the influence of heat and its weight which means that its end, which must be gripped by the gripping device of the drilling machine, is slightly offset from the axis of the tap hole and the axis of this gripping device.

Another factor to take into account is that of the type of machines used and more particularly of the approach path to the lookout. In fact, for the device or the guide and support head located at the front of the mount to be able to be threaded onto the end of the piercing rod, the final phase of the approach movement must be the lookout evolves substantially in the axis of the piercing rod. However, this condition is rarely fulfilled for a machine designed for a conventional drilling process.

Indeed, many of these machines are designed to bring the carriage into the working position by means of a rotation around a vertical or slightly inclined pivot so that the gripping device is not really aligned until the end of the movement. with the piercing rod while during the last phase of the movement the carriage and the gripping device approach, either on one side or by the other of the axis of the piercing rod. In other words, at the moment when the guide plate and the two supports fixed generally at the front of the mount are at the end of the piercing rod, the opening of this plate intended to be engaged in the rod drilling hole is either on one side of the rod or on the other and cannot penetrate into it.

One of the only machines capable of moving the front end of the carriage substantially in the axis of the tap hole during the final approach phase is proposed by French patent application No. 7827 850. For this machine, the problems discussed above have been solved thanks to the aforementioned Luxembourg patent which provides a guide and support head fixed to the front of the carriage to be threaded on the drilling rod and to ensure alignment between it ci and the gripping device. According to this patent, this guide head has a funnel-shaped opening for gripping the end of the piercing rod and compensating for the slight offset that may still exist, either as a result of the trajectory of the mount, or as a result of '' incorrect orientation of the drill rod. However, the subject of this patent has not made it possible to solve the problems for other machines, in particular those described above, whose trajectory does not allow the engagement of the guide head on the drilling rod.

The object of the present invention is to solve this problem for this type of machine by means of a simple and effective centering and guiding device designed to be fixed on the front part of the carriage of a drilling machine.

To achieve this objective, the device proposed by the invention is essentially characterized by a clamp of which at least one of the jaws is pivotable about an axis substantially parallel to the axis of the gripping device, at least one of the the jaws being, moreover, bent or curved so as to delimit, in the closed position, between the jaws an opening large enough for the passage of the piercing rod.

One of the jaws is preferably fixed and secured to the carriage, while the other jaw is carried by a rotary shaft actuated by a hydraulic or pneumatic cylinder.

The invention also relates to a machine for drilling a tap hole of a shaft furnace comprising a working tool mounted on a carriage and capable of sliding along the latter and provided with a device for gripping a drilling rod, characterized by a centering and guiding device of the type described above, fixed to the front end of the mount, so that, in the closed position of the clamp, the opening remaining between the jaws located in alignment with the axis of the gripping device of the piercing rod.

• la figure 1 montre un premier exemple du mouvement d'approche vers la position opérative d'une machine à laquelle s'applique l'objet de la présente invention,
• la figure 2 montre un deuxième exemple de la phase d'approche vers la position opérative d'une machine à laquelle s'applique l'objet de la présente invention,
• la figure 3 montre une vue schématique en plan de la partie avant d'un affût d'une machine de perçage pourvue d'un dispositif selon la présente invention,
• la figure 4 montre schématiquement une section suivant le plan de coupe IV-IV de la figure 3 lorsque la pince est en position ouverte,
• les figures 5 et 6 montrent des vues correspondant respectivement à celles des figures 3 et 4 lorsque la pince est en position fermée.

Other particularities and characteristics will emerge from the detailed description of an advantageous embodiment, presented below, by way of illustration, with reference to the appended figures, in which:

• FIG. 1 shows a first example of the approach movement towards the operative position of a machine to which the object of the present invention applies,
• FIG. 2 shows a second example of the approach phase towards the operative position of a machine to which the object of the present invention applies,
• FIG. 3 shows a schematic plan view of the front part of a carriage of a drilling machine provided with a device according to the present invention,
• FIG. 4 schematically shows a section along the section plane IV-IV of FIG. 3 when the clamp is in the open position,
• Figures 5 and 6 show views corresponding respectively to those of Figures 3 and 4 when the clamp is in the closed position.

We will first explain the problem by referring to the two examples illustrated by Figures 1 and 2. In these figures the reference 10 designates the base of the wall of a blast furnace. The reference 12 represents the taphole obstructed by a plugging mass 14, such as hardened clay, through which a drilling rod 16 has been introduced before hardening. This drilling rod 16 is abandoned in the position shown until the next taphole opening operation, which consists in removing the piercing rod 16 to release the opening of the taphole 12. To facilitate gripping of this rod 16, by means of a suitable instrument, this rod is provided at its end with a circular groove 18 or other equivalent means.

To extract the piercing rod 16, we use a working tool equipped with a percussion member that can strike in both directions. In the figures, the reference 20 shows the mounting of a drilling machine equipped with such a percussion member not shown. _S ince this tool is designed to travel along the mounting 20, can be used to extract the piercing rod 16, on condition that they provide a gripping device which can seize the rod 16 by the groove 18. However, for this gripping device to be able to grip the piercing rod, there must be alignment between the latter and the axis of the gripping device. In addition, it is necessary that during the extraction of the rod 16, it is held in one way or another when it no longer has support in the taphole 12. It is the reason is generally provided on the front part of the mount 20 a plate provided with an axial hole in which the rod 16 can slide and in which it is supported. However, the presence of this plate implies that the carriage is brought into the operative position along the axis of the taphole so that this opening can be engaged on the outgoing end of the rod 16. However, by observing the movement path of the carriage 20, path shown diagrammatically by the dashed line A, it can be seen that this line is a curve, and at the end of the piercing rod 16, this curve does not correspond with the axis of the piercing rod 16 so that it cannot penetrate through the opening of the aforementioned guide plate.

Figure 2 shows another example of the lookout trajectory when approaching the operative position. Whereas in the case of FIG. 1 the axis of the carriage and its gripping device is beyond the axis of the piercing rod at the time of approach towards the operating position, seen from the side of the pivot around which the carriage 20 rotates, the gripping device, the trajectory of which is represented by curve B, remains _{below that} of the drilling rod 16 and the problem is ultimately the same for the two examples Figures 1 and 2.

It should be noted that the two examples in Figures 1 and 2 are typical examples of common machines in which the carriage rotates around a main pivot not shown which is generally vertical or slightly inclined.

FIGS. 3 to 6 illustrate an embodiment of a centering device proposed by the present invention for correcting this offset when the end of the piercing rod 16 is approached. For this purpose, a clamp represented by 22 and comprising two jaws 24 and 26 is provided at the front end of the mount 20. In the embodiment shown, the jaw 26 is fixed and has a substantially straight inner edge, while the jaw 24 which is curved or bent is carried by a rotating shaft 28. This shaft is connected by an arm 30 to the rod 32 of a jack 34 or of an electromechanical motor. The action of this jack 34 allows the jaw 24 to pivot between an open position according to FIG. 4 and a closed position according to FIG. 6.

The piercing rod 16 is shown in an ideal central position aligned with the gripping device not shown. The particular shape of the jaw 24 is intended to define a relatively large opening surface between the jaws 24 and 26 and to define, in position 26, a closed central surface (see FIG. 6) in which the rod 16 can slide.

When approaching the operative position, the clamp 22 is open according to FIG. 4. Consequently, the offset relative to the piercing rod 16 when approaching the latter, as shown in FIGS. 1 and 2 , does not matter, if this offset does not exceed the opening width between the inner edges of the two jaws 24 and 26, that is to say that the rod 16 must pass through the opening between these jaws. In the final position the cylinder 34 will be actuated to close the clamp 22 and completely frame the rod 16 in its position according to FIG. 6. Even if, in the working position of the carriage 20, the rod 16 is not exactly located in the central position shown in FIG. 4, the movement of the jaw 24 will ensure this central position when passing from the position of FIG. 4 to the position of FIG. 6.

Alternatively, the jaw 26 may, instead of being fixed, also be pivotally mounted and be actuated in synchronism with the jaw 24. Whether fixed or pivoting, the jaw 26 may, in addition, also have a bent or curved shape in order to define together with the jaw 24, in the closed position a passage ensuring the maintenance and the guiding of the piercing rod 16.

In the case of the embodiment illustrated in FIGS. 3 to 6, the fixed jaw 26 will be located on one side or the other depending on whether the mount approaches in accordance with FIG. 1 or according to FIG. 2. This fixed jaw 26 will always be on the side where the distance from the trajectory is located with respect to the end of the piercing rod 16 when the end of the carriage approaches the latter. In other words, in the case of FIG. 1 the fixed jaw 26 will be on the right while looking towards the taphole, while in the case of FIG. 2, the fixed jaw 26 will be fixed on the left side of the lookout 20.

Claims (4)

1. Device for centering and guiding a piercing rod (16) of the tap hole (12) of a shaft furnace suitable for a method according to which the opening and closing of the tap hole respectively comprise an operation extraction and a resetting operation of the piercing rod (16) which is abandoned in the tap hole (12) between two successive castings, and designed to be mounted at the front end of the mount (20 ) a taphole drilling machine (12) equipped with a device for gripping the end of the drilling rod (16), which can slide along the mounting (20) of the machine, characterized by a clamp (22) of which at least one of the jaws (24) is pivotable about an axis substantially parallel to the axis of the gripping device, at least one of the jaws (24) being, moreover, bent or curved so as to define, in the closed position, between the jaws (24, 26) an opening large enough for the passage of the piercing rod e (16). 2. Device according to claim l, characterized in that one of the jaws (26) is fixed and integral with the mount (20), while the other jaw (24) is carried by a rotary shaft (28) actuated by a jack (34) or a motor. 3. Device according to claim 2, characterized in that the fixed jaw is on the carriage (20) on the side where there is a gap between the approach path of the carriage and the piercing rod (16). 4. Machine for drilling a tap hole of a shaft furnace comprising a working tool mounted on a carriage (20) and capable of sliding along the latter and provided with a device for gripping a rod drilling (16), characterized by a device for centering and guide according to any one of claims 1 to 3, fixed to the front end of the mount (20), so that, in the closed position of the clamp (22), the opening remaining between the jaws (24, 26) is aligned with the axis of the gripping device of the piercing rod (16).

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