Rock drill machine

[0001] This invention relates to a rock drill machine comprising a frame. Arranged inside the frame is a drill rod movable in an axial direction, and an arrangement to rotate the drill rod. A hammer gear, by use of which hammering pulses are generated to a piston, is arranged to hammer the drill rod rear end in order to transmit hammering pulses through the drill rod which is attachable to the drilling equipment for drilling the drill rod front end. Further, there is in this drilling machine arranged around the drill rod a position sleeve and an arrangement to move the position sleeve in an axial direction towards the hammering piston so that a counter surface in the position sleeve meets a counter surface in the drill rod whereby the drill rod can be moved to the hammering point wanted, while continuing the positioning motion.

[0002] Previously known from Finnish patent publication 114903 is a rock drill machine like the one presented, to whose pulling gear that moves the drill rod forward during rock drilling, a separate force in the opposite direction is also directed when needed. Normally, a push force moves the pulling gear forwards and keeps it at a specified distance from the position corresponding to the hammering point of the drill rod. When the drilling equipment is to be pulled out from the hole, the pulling gear is moved towards the hammering piston, causing a transmission force in the pulling gear. Such a percussion like working is needed when pulling the drilling equipment out of the drill hole, since often the drill tries to wedge into the hole while being removed from the hole.

[0003] The disadvantage of the solution according to publication FI-114903 is that for the pulling gear a moving arrangement in both directions is needed. When the movements are done by means of pressure medium, the cylinder, piston and packing solutions become quite complicated. In addition, control valves are necessary for both positioning moves, and during pulling out the drilling equipment hammering pulses are transmitted strongly into the drill frame, since there are no spring elements.

[0004] By use of a rock drilling machine according to the invention, the need of many positioning movements and their controls are avoided. Only one moving direction has to be carried out, and when the return movement in the opposite direction is required it is freely taking place during operation of the drilling machine. During pulling out of the drilling equipment, there is due to the simple spring-arrangement a strong tendency to pull-off with the impulses, whereby the drill is not strained by harmful hammering as much as in known solutions. Also the behavior of the drilling during pulling out according to the solution of the invention departs essentially from known solutions, since energy bound to flexibility throws the drilling equipment backwards in regard to the frame in a quite other way. This solution is effective, among other things, in pulling out the drilling equipment from the hole, especially if it has already gotten stuck. It is easy to form one cylinder space in the drill frame as well as placing a piston furnished with one pressure surface in it.

[0008] FIG. 1 shows the rock drilling machine furnished with a frame 3 and a frame 4, where there is inside of the frames 3 and 4 a drill rod 2 movable along and rotating about an axial direction thereof. Drill rod 2 is rotated by rotation axle 5 coming from a turning gear (not shown), and from which, by way of rack transmission 15, the rotation is transferred to outside sleeve 6 of drill rod 2. The inside of sleeve 6 is grooved and, correspondingly, there is on drill rod 2 a grooving 7 which transmits the rotation to drill rod 2 and which allows the drill rod 2 to move also in the axial direction as much as needed. In the drilling operation presented by FIG. 1, the back and forth moving of piston 1, which produces hammering pulses, hammers the back end of drill rod 2 and produces in the drill rod 2 forward hammering pulses. In front of drill rod 2, the hammering drilling equipment is connected, which gets the hammering pulses transmitted by drill rod 2.

[0009] The drilling machine has according to the invention a position sleeve 9 that positions the drill rod 2. In this drilling operation of FIG. 1, position sleeve 9 is freely drifted to its foremost position. As a result, position sleeve 9 is maximally spaced from counter shoulder surface 12 of drill rod 2. In particular, it will be noted that counter surface 12 does not reach to counter surface 13 of position sleeve 9 when drill rod 2 is making the back and forth hammering motion in the drilling operation. In the drilling operation shown by FIG. 1, piston 1 (which produces back and forth moving hammering pulses) always hammers the back most possible and the most wanted portion of the drill rod 2, that is moment piston 1 hammers the back end of drill rod 2. Due to hammering pulses, drill rod 2 moves a few millimeters forward and returns back. Position sleeve 9 functions like a piston in the cylinder space formed in the drilling machine frame 3. No pressure medium is led through channel 8 to the cylinder space during the drilling operation, but the pressure medium is free to flow out from the cylinder space so that position sleeve 9 can drift to the position presented in FIG. 1 and stay there. No matter the starting position when drilling commences, ultimately, the counter surface 12 of drill rod 2 hammers into position sleeve 9 via ring 10, and thus moves the position sleeve 9 to the position of FIG. 1.

[0010] By use of the new simple position sleeve 9 as set forth hereafter, a solution according to the invention is provided whereby hammering pulses are easily produced, and whereby the hammering pulses assist in the pulling out of the drilling equipment from the hole.

[0011] On pulling out the drilling equipment, by use of piston 1, hammering pulses are produced, as also made during hole drilling. But in pulling out, position sleeve 9 is moved towards hammering piston 1 along drill rod 2 as shown. FIG. 1 shows that position sleeve 9 has a distance from counter surface 14 to the drilling machine rear end when position sleeve 9 is moved in that direction during drilling. In this example, rearward moving of position sleeve 9 takes place by use of a pressure medium which is transmitted through channel 8 and thus against counter surface 16 of position sleeve 9. The pressure is left in channel 8 to effect the pulling out during the whole pull-off procedure. When position sleeve 9 is in the FIG. 2 position, ring 10 is connected through spring element 11 to sleeve 9, and thus ring 10 pushes drill rod 2 always to a (rearward) starting position chosen which is towards the hammering piston. When piston 1 hammers, the hammering pulse goes from drill rod 2 through ring 20 to spring element 11 as binding (or compression) energy, and a part of the hammering to frames 3, 4. The drill equipment thus produces a slight hammering in the hole. The binding (compression) energy in spring element 11 then returns the drill rod 2 with a strong pulse against the hammering piston 1, and at the same time pulls also the drill equipment outwards in the hole.

[0012] On pulling out, while the hammering piston 1 is producing pulses to drill rod 2, the impact of the pulses can be turned to pulses which help pull out the drill equipment from the hole by use of the positioning sleeve 9 according to the invention, and by use of spring element 11 which stores and transmits energy. By pulling out, frames 3, 4 of the drilling machine are pulled by appropriate force out of the hole. Frames 3, 4 represent a great mass, and drill rod 2 and the drilling equipment a small mass and thus fast motion. Pulling out the drilling equipment from the hole is easier essentially when a small back and forth motion can be conveyed to drilling equipment in addition to just a pulling force.