Drill Rod

Abstract

According to the present invention, a drill rod (10) comprises an elongate hollow shaft (12) with a first shaft end and a second shaft end (22), the first shaft end having a first connector for connecting the drill rod (10) to a drive mechanism, the second shaft end (22) having a first female tread (24); and an adapter (30) with a first adapter end (32) and a second adapter end (34), the first adapter end (32) having a first male thread (42) cooperating with the first female tread (24) of the second shaft end (22), the second adapter end (34) having a second connector for connecting a drill bit (46) thereto. When a drill bit (46) is connected to the drill rod (10), the adapter (30) is sandwiched between the hollow shaft (12) and the drill bit (46). The above configuration of drill rod allows a great variety of drill bits to be used in conjunction with a single hollow shaft. There is hence no need to provide a different hollow shaft if a different drill bit is to be used. Manufacturing costs of drill rods do hence not have to be considerably-increased if a variety of drill bits are to be used.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to a drill rod, in particular to a drill rod of a tapping device for use in the iron and steel making industry.BRIEF SUMMARY OF RELATED ART[0002]Historically, blast furnaces, electric arc furnaces, and related vessels used for producing, transporting, or otherwise containing molten material, are opened for releasing the liquefied material, by a drilling process called “tapping”. In order to carry out the tapping process, tapping devices are provided. Such tapping devices generally comprise a motor for imparting impact and rotation forces to a drill rod, at the end of which a drill bit is arranged for penetrating into the vessel to be opened. A drill rod comprises a hollow, steel drill shaft, sized and manufactured to adequately transmit the rotary and impact forces to the refractory material allowing effective creation of a drill hole within the vessel or containing body.[0003]The common design of the drill rod comp...

AI Technical Summary

Benefits of technology

[0011]The above configuration of drill rod allows a great variety of drill bits to be used in conjunction with a single hollow shaft. There is hence no need to provide a different hollow shaft if a different drill bit is to be used. Manufacturing costs of drill rods do hence not have to be considerably increased if a variety of drill bits are to be used.

[0013]The second connector of the second adapter end preferably comprises a second male thread and the third connector of the drill bit preferably comprises a second female thread cooperating with the second male thread of the second connector of the second adapter end. This allows easy and fast connection of the drill bit to the adapter.

[0015]According to an important aspect of the invention, the adapter further comprises a plurality of orifices in its circumferential wall, the orifices being fluidly connected to the fluid conduit. Such orifices allow fluid to be delivered between the drill rod and the drilled hole in order to further improve cooling of the drill bit and to improve evacuation of debris from the drilled hole.

[0017]According to one embodiment, the orifices are arranged in a collar between the first male thread of the first adapter end and the second connector of the second adapter end, the collar having a diameter larger than the diameter of the first and second adapter ends. The collar can comprise a chamfered portion with a diameter gradually decreasing in direction of the first adapter end, and the orifices can be arranged in the chamfered portion of the collar. Such an arrangement of the orifices further improves evacuation of debris from the drilled hole.

Problems solved by technology

It follows that drill bits from different manufacturers cannot generally be used on the same drill shaft.

The material presently used for the manufacture of drill shafts is not commonly available and the necessary raw material is difficult to acquire.

It follows that the costs of such drill shafts are therefore relatively high.

In addition to the direct purchasing costs of the material, further costs for forging and threading have to be taken into account.

However, by increasing the inner diameter of the drill shaft, the material thickness of the drill shaft at the drill bit end is reduced, thereby reducing the strength of the connection between the drill bit and the drill shaft.

In case of insufficient strength of the connection between the drill bit and the drill shaft the drill bit can break off the drill shaft during operation and jeopardize the drilling process.

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