Boring or penetrating the earth – Automatic control – Of fluid pressure below ground
Reexamination Certificate
1999-05-18
2001-04-03
Pezzuto, Robert E. (Department: 3671)
Boring or penetrating the earth
Automatic control
Of fluid pressure below ground
C173S001000, C173S158000
Reexamination Certificate
active
06209661
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method for controlling the feed of a pressure-fluid-operated rock drilling apparatus when a rock drill is fed forward by a pressure-fluid-operated feed motor.
The invention further relates to an arrangement for controlling the feed of a pressure-fluid-operated rock drilling apparatus comprising a rock drill, a feed beam along which the rock drill moves, a pressure-fluid-operated feed motor for moving the rock drill along the feed beam, control means for adjusting the feed of the rock drill, and means for adjusting the flow of the pressure fluid and thereby the feed rate of the feed motor.
The aim in rock drilling is on the one hand to control the entire drilling operation such that ineffective time can be minimized and on the other hand to conduct the actual drilling operation such that a hole can be drilled as close to the desired position as possible, while the apparatus is subjected to as little wear and damage as possible. In practice, the impact and rotation parameters and the feed of the rock drill in today's rock drilling apparatus can be adjusted by different controls. In practice, solutions widely used are the ones in which the drilling power is adjusted and an automatic control adjusts both impact and feed pressure in accordance with pre-set control parameters. Because the rock to be drilled and the drilling situations vary, there usually also exists a separate manual feed control system by which the feed pressure can be deflected from the pressure defined by the parameters, so that the drilling operation can also be adjusted in accordance with the conditions. In connection with collaring, or before the actual drilling is started, it is, however, difficult to adjust the drilling operation by adjusting the pressure of the feed, since the feed pressure does not take into account, for example, the effect of an inclined surface on the motion of the drill bit and on the bending of the drill rod, and the drilling step is therefore not very easy to adjust at present. The position of the feed apparatus and various friction factors in the feed apparatus as such make it impossible to accurately control the collaring step and the moving of the drill bit to the rock surface with one and the same pressure value.
SUMMARY OF THE INVENTION
The object of the present invention is to provide such a method and arrangement for controlling the feed in rock drilling that the rock drilling operation can be better adjusted, if desired, in the collaring step and also during the actual drilling under exceptional conditions.
The method of the invention is characterized in that at least in the collaring step the pressure of the pressure fluid in a pressure conduit of the feed motor is measured, that when the pressure of the pressure fluid is below a pre-set threshold value, the volume flow of the pressure fluid delivered to the feed motor is adjusted so as to adjust the feed rate, and that when the pressure of the pressure fluid is above said pre-set threshold value, the feed is controlled by adjusting the pressure of the pressure fluid delivered to the feed motor.
The arrangement of the invention is characterized in that the arrangement comprises a pressure detector that is arranged to detect the pressure of the pressure fluid in the pressure conduit of the feed motor; and that the pressure detector is arranged to control the control means in such a way that when the pressure in the pressure conduit of the feed motor is below a pre-set threshold value at least in the collaring step, the control means are arranged to adjust the volume flow of the pressure fluid and thereby the feed rate of the feed motor, and that when the pressure in the pressure conduit of the feed motor is above the value pre-set for the pressure detector, the control means are arranged to control the pressure of the pressure fluid in the pressure conduit of the feed motor.
The essential idea of the invention is that when the drill bit is moved toward the rock in the collaring step, the feed rate at which the drill bit moves toward the rock is adjusted. If, for example, the surface is inclined, the feed rate at the beginning of the drilling operation can be adjusted to be low, so that the collaring will not bend nor incline the drill apparatus, which is what would happen if the feed pressure were adjusted. Another essential idea of the invention is that when a proper rock contact has been established so that there is no risk of bending or inclining, the feed control automatically switches to normal feed pressure, and from then on the drilling operation is conducted under the control of normal drilling parameters.
The advantage of the invention is that the rock contact can be established and the collaring conducted accurately and carefully by adjusting of feed rate, whereby the drilling is simple and easy for the user to control. Correspondingly, if the drill bit is in firm contact with the rock to be drilled, normal drilling, where the adjustment is based on the adjustment of pressure, is safe to use. In this way, the drilling control is comfortable and operatively logical for the user to control. The method of the invention helps to avoid mispositioning of drill holes, and faults in the machinery, and simultaneously makes the apparatus easier to use.
REFERENCES:
patent: 3561542 (1971-02-01), Hanson et al.
patent: 4271914 (1981-06-01), Dressel
patent: 4275793 (1981-06-01), Schivley, Jr. et al.
patent: 1118766 (1984-10-01), None
patent: 95/28549 (1995-10-01), None
Pezzuto Robert E.
Sandvik Tamrock Oy
Smith-Hill and Bedell
LandOfFree
Method and arrangement for controlling feed in rock drilling does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and arrangement for controlling feed in rock drilling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and arrangement for controlling feed in rock drilling will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2516165