FEED-EXTENSION CYLINDER ARRANGEMENT IN A FEED BEAM FOR A ROCK DRILL

Abstract: A feed-extension cylinder arrangement in a feed beam for a rock drill, the feed beam comprising a lower beam (2) and an upper beam (1) positioned slideably on top of it. The cylinder pipe of a feed-extension cylinder (6) between the lower beam (2) and the upper beam (1) is fixed in a chute-like space (2c) of the lower beam (2) to the lower surface of the upper beam (1) immovably with respect to it. The piston rod (7) of the feed-extension cylinder (6) is connected at its end to the rear end of the lower beam (2) movably in its transverse direction, so that the feed-extension cylinder (6) and the piston rod (7) are always protected against damage, being positioned between the upper beam (1) and the lower beam (2).

Description: Feed-extension cylinder arrangement in a feed beam for a rock drill The invention relates to a feed-extension cyl- inder arrangement in a feed beam for a rock drill, the feed beam comprising a lower beam and an upper beam, the lower beam having two vertical side portions and a transverse bottom between the side portions so that the side portions and the bottom define between them a chute-like space, upon the open side of which the upper beam is mounted longitudinally slideably with respect to the lower beam; and a feed-extension cyl¬ inder connected to act between the upper beam and the lower beam, the feed-extension cylinder being mounted in the chute-like space of the lower beam below the upper beam, and the cylinder pipe of the feed- extension cylinder and its piston rod being connected to act between the upper beam and the lower beam so that when the feed-extension cylinder is extended, it displaces the upper beam towards the front end of the lower beam, and when the feed-extension cylinder is shortened, it displaces the upper beam towards the rear end of the lower beam. Telescopic or extension feed beams comprise two superimposed beam portions, i.e. a lower beam and an upper beam slidable upon it. In the drilling process, longer holes are drilled at two stages, i.e. the drill moves along the upper beam by means of a feed device formed by a cylinder and a wire, while the upper beam is displaced upon the lower beam by means of a separ¬ ate feed-extension cylinder in order that the entire feed length of the beam could be utilized. In prior art solutions, the cylinder displacing the upper beam has been realized by fixing one end of the cylinder pipe to the lower beam and the piston rod to the upper beam so that it protrudes from the rear end of the lower beam when the upper beam has been displaced backwards. A disadvantage of this solution is that the piston rod is unprotected and subject to dirt and damage. This in turn increases the demand of main¬ tenance and various maintenance costs. The object of the present invention is to provide an arrangement, which avoids the known dis¬ advantages and provides a structure as simple and reliable as possible. The arrangement according to the invention is characterized in that the cylinder pipe of the feed-extension cylinder is fixed to the lower beam or to the upper beam immovably with respect to it, and that the piston rod is correspondingly con- nected at its end to the front end of the upper beam or to the rear end of the lower beam so that it is able to move in the transverse direction of the upper beam and the lower beam, respectively, but is substan¬ tially immovable in its longitudinal direction. An essential aspect of the invention is that the cylinder pipe of the feed-extension cylinder between the upper and the lower beam is attached to the front end of the upper beam on the side of the lower beam, and the end of the piston rod of the feed-extension cylinder is connected to the rear end of the lower beam, or vice versa . When the piston rod is in its most extended position from the feed-extension cyl¬ inder, the upper beam covers the opening above the lower beam entirely. Correspondingly, when the upper beam is displaced backwards upon the lower beam, the piston rod is displaced within the cylinder, and so the piston rod is all the time effectively protected from dirt and dust. Being positioned between the lower beam and the upper beam, the piston rod is also all the time protected by them so that stones or other objects cannot hit it. In contrast to known solutions, it thus cannot be damaged. In the preferred embodiment of the invention, the cylinder pipe of the feed-extension cylinder is connected immovably to the lower surface of the upper beam and the end of its piston rod is connected "floatingly" to the rear end of the lower beam so that it will always be positioned appropriately with respect to the cylinder. The structure is thus easy to manufacture and assemble as well as disassemble for maintenance, as the upper beam can be placed upon the lower beam and removed from it simply by lowering and lifting it in position and attaching slides or detach¬ ing them before lifting. The invention will be described more fully with reference to the attached drawings, in which Figure 1 illustrates a feed-extension cylinder arrangement according to the invention as seen from the side of the feeding beam shown in a partial section; Figure 2 is a schematic sectional view of the feed-extension cylinder arrangement shown in Figure 1 in the transverse direction of the feed beam along line A-A indicated in Figure 1; Figure 3 is a schematic view of the mounting of the end of the piston rod of the feed cylinder to the lower beam; Figure 4 is a schematic view of a hydraulic con¬ nection for the preferred embodiment of the arrange- ment according to the invention; and Figure 5 is a more detailed schematic view of another embodiment of the arrangement according to the invention. Figure 1 shows a feed beam comprising an upper beam 1 and a lower beam 2. The upper beam 1 and the lower beam 2 are positioned mutually longitudinally slideably by means of slide rails la provided at the lower edge of the upper beam 1 and slide means 3 attached to the lower beam. The upper beam 1 is pre- ferably made of an aluminium alloy by extrusion, its slide surfaces being preferably formed simultaneously. The slide rails are provided with slide surfaces 4, usually steel strips or the like, for the slide means. The slide means 3 in turn are preferably formed by aluminium profiles, to which slides shown in Figure 2 are attached. The slides are in contact with the slide surfaces 4. The slide means 3 in turn are attached to the lower beam 2 by means of bolts 5. At the front end of the lower beam 2, the slide means extend substan- tially over the entire travel length of the upper beam 1, so that the slides support the upper beam over its entire length, while the aluminium profiles stiffen the low lower beam at the front end. If desired, the slide means 3 may extend over the entire length of the lower beam 2, and slides may be positioned within a desired portion of the aluminium profile. A feed-extension cylinder 6 is provided below the upper beam 1, and the cylinder pipe of the feed- extension cylinder is attached to the lower surface of the upper beam 1. The feed-extension cylinder 6 is preferably fixed to the upper beam 1 rigidly and im¬ movably so that it cannot turn relative to it. A piston rod 7 of the feed-extension cylinder 6 in turn is attached at its end to the rear end of the lower beam 2. The feed-extension cylinder 6 may be fixed e.g. by flanges 6a attached to the cylinder pipe of the cylinder 6 and bolts 8 driven into the flanges through the bottom plate lb of the upper beam 1. The figure also shows a rock drill 9 intended to move along the upper beam, and a drill carriage 10 mounted in a manner known per se slideably along second slide rails lc provided at the upper edge of the upper beam 1. To displace the rock drill 9 and the carriage 10, a feed cylinder 11 is provided within the upper beam 1, and an idler wheel 12 is connected to the cylinder pipe of the feed cylinder 11. A feed wire 13 in turn passes around the idler wheel 12. It is connected both to the drill carriage 10 and to the upper beam 1. This kind of feed cylinder/wire structure is as such well- known, and therefore it will not be described more closely herein. When pressure fluid is introduced into the feed cylinder 11, its piston rod is expelled and the cylinder pipe moves towards the front end of the upper beam, thus pushing the feed wire 13 ahead of it by means of the idler wheel, and so the rock drill 9 and the carriage 10 move on at a speed twice as high as that of the idler wheel 12. Correspondingly, when the piston of the feed cylinder is retracted, the rock drill moves to the rear portion of the upper beam 1 in a manner known per se. The figure also shows a travelling centralizer 14 provided for a drill rod at the front end of the upper beam 1, and a front cen¬ tralizer 15 at the front end of the lower beam 2. Such centralizers are fully known per se, and are not essential to the present invention, wherefore they will not be described more closely herein. Figure 2 is a sectional view of the feed beam structure shown in Figure 1 along line A-A. As appears from Figure 2, the lower beam 2 is formed by vertical side portions 2a and a transverse bottom plate 2b posi¬ tioned between the side portions. A chute-like space 2c is defined between the side portions and the bottom plate. The feed-extension cylinder 6 is positioned in the space 2c below the upper beam 1. As appears from Figure 2, the upper edge of the cylinder pipe of the feed-extension cylinder 6 is provided with a fixing flange 6a, which fixes the cylinder at its both ends immovably to the upper beam 1. In this way, the feed- extension cylinder 6 and its piston rod 7 remain all the time between the upper beam 1 and the lower beam 2, being thus protected. The aluminium profiles 3 having slides 3a inside them are attached by means of the bolts 5 to the edge flanges 2d provided at the edge of the side portions of the lower beam 2. The slides 3a in turn are in contact with the slide sur¬ faces 4 of the slide rails la of the upper beam 1 so that the upper beam and the lower beam slide in close contact with each other. Figure 3 schematically illustrates one way of mounting the end of the piston rod 7 of the feed- extension cylinder 6 longitudinally immovably with respect to the lower beam 2 while however allowing it to "float" in the transverse direction. This is done e.g. by fixing a connection piece 7a, such as a round or angular flange or plate, to the end of the piston rod 7. The connection piece in turn is mounted to an abutment 16 attached to the end of the lower beam 2. The abutment is provided with a slot 16a, into which the connection piece 7a can be fitted transversely movably, and with a groove 16b for the piston rod 7, which can move in the groove in the transverse direction of the lower beam 2. Figure 4 is a schematic view of a hydraulic con¬ nection suitable for operating the feed beam according to the invention, where the feed-extension cylinder 6 and the feed cylinder 11 are interconnected hy- draulically so that their forces will be equal. This is realized by connecting the two cylinder spaces of the feed-extension cylinder 6 in communication with a feed line for pressure fluid during the drilling, so that fluid introduced through the line 17 is admitted into both the feed-extension cylinder 6 and the feed cylinder 11 into a space which is not occupied by the piston rod. From the line 17, the hydraulic fluid is able to flow through a shuttle valve 18 into the feed- extension cylinder space on the side of the piston rod 7. When an exhaust line 19 is closed by the shuttle valve 18, the hydraulic fluid acts on the feed- extension cylinder 6 in proportion to the effective areas of its piston. Accordingly, when the areas are selected suitably, the force will be equal to that of the feed cylinder 11. Correspondingly, when hydraulic fluid is introduced through the line 19 into the feed- extension cylinder 6 into the space on the side of its piston rod and into the feed cylinder 11 into the space on the side of its piston rod, the shuttle valve 18 closes the connection to the line 17, and both of the cylinders move into their most retracted position so that the upper beam will move into its rearmost position with respect to the lower beam and the rock drill 9 returns to the rear end of the upper beam 1. Figure 5 shows a feed beam similar to that shown in Figure 1, and its reference numerals correspond to those of Figure 1. An essential difference is, how- ever, that the cylinder pipe of the feed-extension cylinder 6 is secured immovably to the lower beam 2, and the rod 7 of the feed-extension cylinder 6 is attached to the upper beam 1 movably in its transverse direction but substantially immovably in the longitud- inal direction. The operation and reference numerals of the equipment correspond to those of Figure 1 except that in this case the cylinder pipe of the feed-extension cylinder 6 remains immovable when the upper beam 1 moves with respect to the lower beam 2. The invention has been described above and shown in the drawings by way of example, and it is not in any way restricted to the example. The feed mechanism of the rock drill need not be a feed cylinder/wire mechanism, but it may also be a feed cylinder mechan¬ ism of some other type, even though the cylinder/wire mechanism is advantageous in use.

Claims: Claims : 1. Feed-extension cylinder arrangement in a feed beam for a rock drill, the feed beam comprising a lower beam (2) and an upper beam (1), the lower beam (2) having two vertical side portions (2a) and a transverse bottom (2b) between the side portions so that the side portions and the bottom define between them a chute-like space (2c), upon the open side of which the upper beam (1) is mounted longitudinally slideably with respect to the lower beam (2); and a feed-extension cylinder (6) connected to act between the upper beam (1) and the lower beam (2), the feed- extension cylinder being mounted in the chute-like space (2c) of the lower beam (2) below the upper beam (1), and the cylinder pipe of the feed-extension cyl¬ inder (6) and its piston rod (7) being connected to act between the upper beam (1) and the lower beam (2) so that when the feed-extension cylinder is extended, it displaces the upper beam (1) towards the front end of the lower beam (2), and when the feed-extension cylinder (6) is shortened, it displaces the upper beam (1) towards the rear end of the lower beam (2), c h a r a c t e r i z e d in that the cylinder pipe of the feed-extension cylinder (6) is fixed to the lower beam or to the upper beam (1) immovably with respect to it, and that the piston rod (7) is corre¬ spondingly connected at its end to the front end of the upper beam (1) or to the rear end of the lower beam (2) so that it is able to move in the transverse direction of the upper beam (1 ) or the lower beam (2), respectively, but substantially immovably in its longitudinal direction. 2. Feed-extension cylinder arrangement according to claim 1 , c h a r a c t e r i z e d in that a feed cylinder (11) for the rock drill and the feed- extension cylinder are hydraulically interconnected so that the feed forces of the feed cylinder and the feed-extension cylinder are equal throughout the drilling process. 3. Feed-extension cylinder arrangement according to claim 2, c h a r a c t e r i z e d in that one feed line (17) for hydraulic fluid is connected to both the feed cylinder (11) and the feed-extension cylinder (6) to a cylinder space unoccupied by the piston rod, that said feed line (17) is also connected through a shuttle valve (18) to the cylinder space of the feed-extension cylinder (6) on the side of the piston rod (7), that another feed line for pressure fluid is connected to the cylinder space of the feed cylinder (11) on the side of the piston rod and through said shuttle valve (18) to the cylinder space of the feed-extension cylinder on the side of the piston rod (7), and that the effective areas of the piston of the feed-extension cylinder (6) have such dimensions that when hydraulic fluid is fed through the feed line (17), the pressure of the hydraulic fluid acts on the feed cylinder (11) and at the same time on both cylinder spaces of the feed-extension cylinder (6) so that the forces created by the feed- extension cylinder (6) and the feed cylinder (11) are substantially equal.

Inventors: HAEKKINEN LEO, JANTUNEN HEIKKI, HAEKKINEN, LEO, JANTUNEN, HEIKKI
Applicants: HAEKKINEN LEO, JANTUNEN HEIKKI, TAMROCK OY, HAEKKINEN, LEO, JANTUNEN, HEIKKI
Application year: 1995
Main classification: E21C11
IPC codes: E21B19