Arrangement in a feed equipment of a feed beam of a rock drill
The invention relates to an arrangement in a feed equipment of a feed beam, said arrangement comprising a feed cylinder the piston rod of which is arranged to be stationary in the longitudinal direction of the feed beam, a carriage for a rock drill arranged to be mobile in the longitudinal direction of the feed beam, a first idler wheel mounted at the free end of the cylinder liner of the feed cylinder, a second idler wheel mounted at the opposite end of the cylinder liner, a feed wire attached from its one end to the rear end of the feed beam and from its point of attachment towards the front end of the feed beam and mounted to move backwards around the first idler wheel and connected from its end to the carriage, and correspondingly, a return wire attached to the front end of the feed beam and mounted from its point of attachment to move backwards and further around the second idler wheel towards the front end of the feed beam and attached from its end to the carriage.
These kinds of wire cylinder feed mechanisms are typically used in tunnel drilling feed equipments in which the feed mechanism should be in a small space and still operate reliably. Usually one pull wire and one return wire are used in the structure which are situated at the middle line of the feed cylinder seen from the above. In this case the idler wheel of the pull wire is on an extension of the front end of the feed cylinder. The wires are attached to the carriage of the drill so that the pull wire is attached to the upper surface of the front end of the carriage and the return wire is attached to the upper surface of the rear end of the carriage. In order that the idler
wheels could be easily be mounted to maintain a certain distance from one another, they are attached to the cylinder liner and the piston rod of the feed cylinder is attached to the feed beam, respectively. A problem of the prior art arrangements is that the movement of the carriage of the drill is restricted only to the length of the feed beam, whereby the maximum length of the drill rods to be used is significantly shorter than the length of the feed beam. Further, the so-called dead length of the feed cylinder, that is, the length of the feed cylinder that cannot be utilized is relatively large as the idler wheel of the pull wire has to be placed at the front of the feed cylinder. Moreover, if the wire breaks, the movement of the drill cannot be controlled. The transfer of the wire at the middle line of the cylinder requires space in the elevation as a result of which the height of the feed equipment will be great . Additionally, the maximum length of the cylinders is directly comparable to the feed distance of the carriage. In situations in which no intermediate travelling centralizers and hose support are used the so-called useless dead length increases as the space required by these additional equipments can normally be used at the same time by mounting e.g. an idler wheel underneath a travelling centralizer and so on.
The object of this invention is to provide an arrangement with which a reliable feed equipment structure is achieved as well as the movement of the carriage of the drill can be extended to be greater than the length of the feed beam. The arrangement of the invention is characterized in that the ends of the feed wire and return wire are attached to the carriage at a distance from one another in such a manner that the point of attachment of the return wire is situated
at the front end of the feed beam and correspondingly, the point of attachment of the feed wire is situated at the rear end of the feed beam, whereby the wires overlap in part underneath the carriage, and that the carriage is mounted slidingly relative to the feed beam so that it can move part of its length outside the end of the feed beam at least at the other end of the feed beam.
The essential idea of this invention is that the pull and return wires are attached to the carriage in such a manner that the end of the pull wire is fastened to the rear part of the carriage and correspondingly, the end of the return wire is fastened to the front part of the carriage so that the wires overlap in part underneath the carriage. A further essential idea of the invention is that the slide pieces of the carriage are mounted in such a manner that the carriage can move part of its length outside the slide guides of the feed beam at least at the other end of the feed beam in its extreme position. Another essential idea of the preferred embodiment of the invention is that two pull wires and also, two return wires are used that are mounted at the side of the feed cylinder, whereby the idler wheels are similarly mounted at the side of the feed cylinder at the feed cylinder.
An advantage of the arrangement according to the invention is that when the wires overlap in part at the carriage, the carriage can be moved almost to the point of attachment of the wire outside the path of the feed cylinder, whereby the carriage can be moved, when desired, the length of the thread length of the drill rod outside the rear part of the feed beam, for example and thus a longer drill rod than usually can be used relative to the length of the feed beam, that is, a
shorter feed beam than now can be used with a drill rod of a certain length. A further advantage of the preferred embodiment is that when using two pull and return wires, the breaking of one wire does not prevent the carriage from being controlled but the carriage can be controllably moved in spite of breaking. Another advantage of the invention is that when mounting the idler wheels at the sides of the feed cylinder, the so- called dead length of the feed cylinder will be shorter than before and at the same time the height of the feed beam will be lower as the wires do not have to travel any more in the elevation of the feed cylinder at its both sides.
The invention will be explained in more detail in the accompanying drawings, in which
Figure 1 shows a schematic, partly sectional side view of the arrangement according to the invention,
Figure 2 shows a schematic, partly sectional top view of the arrangement according to the invention,
Figures 3a and 3b show a schematic view of the arrangement according to the invention of the rock drill carriage in its possible extreme positions, and
Figure 4 shows schematically the cross section A - A of the feed beam indicated in Figure 1.
Figure 1 shows a schematic view of the arrangement according to the invention which comprises a feed beam 1 and a carriage 2 moving along the feed beam on the slide guides shown by way of example below in Figure 4. A rock drill 3 is attached to the carriage 2, the drill being transferred along the feed beam 1 on the carriage 2 by means of a feed cylinder. In the feed cylinder there is a piston rod 4a attached to the rear part of the feed beam 1 from its one end and a cylinder line 4b that moves relative to the feed beam 1 when
feeding pressure medium to either cylinder space. In addition, the figure shows one feed wire 5a which is connected to the rear part of the carriage 2 with brackets 2a and one return wire 6a which is connected to the front part of the carriage with brackets 2b, respectively, in such a manner that the ends of the wires overlap part of the length of the carriage 2 underneath the carriage. The feed wire 5a is mounted to travel around the first idler wheel 7a attached to the free end of the cylinder liner 4b and it is attached at its rear end to the rear part of the feed beam 1. Similarly, the return wire 6a is mounted to travel around the second idler wheel 8a that is mounted at the end of the cylinder liner 4b on the piston rod 4a side and it is attached from its other end to the front end of the feed beam 1. During drilling the cylinder liner 4b is transferred towards the front end of the feed beam, that is, to the left in the figure, whereby the wires 5a and 6a move by the action of the idler wheels and the carriage moves at a double speed relative to the cylinder liner 4b. Correspondingly, the movement of the carriage is twice as long as the movement of the cylinder liner in the equivalent time.
Figure 2 shows a schematic, partly sectional top view of the arrangement of Figure 1 without the drill, which makes it more obvious how the arrangement of the invention is realized. As can be seen in Figure 2, the arrangement preferably uses two feed wires 5a and 5b and also, two return wires 6a and 6b in such a manner that they are parallel to one another in the lateral direction of the feed beam. In that case the pull and attachment of the wires is easy to accomplish. The figure also shows that both feed wires are provided with first idler wheels 7a and 7b of their own situated on both sides of the cylinder liner 4b. The idler
wheels 7a and 7b are connected to the cylinder liner 4b by attaching them to an attachment sleeve 9 around the end of the cylinder liner 4. A guide plate 10 is further attached to the attachment sleeve 9 to which plate guides 11 are attached. This structure is disclosed in more detail in Figure 4. Correspondingly, the return wires 6a and 6b are provided with second idler wheels 8a and 8b of their own which are also situated on both sides of the cylinder liner 4b and in this embodiment also outside the idler wheels 7a and 7b of the feed wires 5a and 5b in such a manner that the return wires 6a and 6b are situated outside the feed wires 5a and 5b in the lateral direction of the feed beam 1. The figure also shows that the return wires 6a and 6b are attached to the front end of the feed beam 1 with retaining screws 12a and 12b and mounting nuts 13a and 13b. In this way the tension of the wires can be adjusted to be suitable and the movement of the carriage in the longitudinal direction of the feed beam 1 be tight. The feed wires 5a and 5b can be attached to the rear part of the feed beam 1 in the same way as the return wires 6a and 6b or they can also be attached in the conventional way without it being possible to adjust. The attachment of the wires is generally known per se and therefore will not be explained more closely herein.
Figures 3a and 3b show a schematic view of the way the carriage of the drill and thus also the drill can be made to extend longer than the length of the feed beam by means of the present invention. Figure 3a shows a situation according to Figure 1 in which the cylinder liner 4b of the feed cylinder is transferred towards the rear end of the feed beam, that is, to the right in the figure as far as it is possible to transfer it. The carriage 2 is arranged to slide
relative to the feed beam 1 on slide pieces 2a which are shorter than the length of the carriage. Thus the carriage 2 can be transferred farther than the rear end of the feed beam 1, which has not been possible in earlier arrangements. The extra movement length L indicated in the figure can be for example longer than the thread length of the outer drill rod, preferably a little more than two times the length of the thread. In that case the drill rod can be easily placed on the feed beam and the threads can be rotated, whereby longer drill rods relative to the length of the feed beam can be used than before or a feed beam shorter in its total length can be used with certain drill rod lengths. Similarly, Figure 3b shows a situation in which the cylinder liner 4b is transferred as far towards the front end of the feed beam as necessary, whereby the carriage 2 extends part of its length over the front end of the feed beam 1 which may be necessary in some situations . These movements extending the length of the feed beam are only possible if the feed and return wires are mounted as in the arrangement according to the invention.
Figure 4 shows a schematic view of the cross section of the feed beam along the line A - A indicated in Figure 1. As can be seen in Figure 4, the guides 11 are attached to the guide plate 10 which guides extend inside the grooves in the upper edge of the feed beam 1, slide in them and thus guide the guide plate 10. Furthermore, in the figure there are slide guides 14 that are attached on top of the guide-like profile parts formed outside the upper part of the feed beam. The use and structure of the slide guides and also of the slide pieces of the carriage are fully known per se and therefore they will not be described in greater detail herein. The guide plate 10 and also possibly the
attachment sleeve 9 are secured to the cylinder liner 4b with bolts 15 so that they cannot rotate in relation to one other. When the idler wheels 7a and 7b seen in Figure 2 are also secured to the attachment sleeve 11, neither will they be able to rotate and the guiding of the feed wires will be steady and controlled. The idler wheels 8a and 8b of the return wires can be equally connected to the other end of the cylinder liner 4b by using a sleeve structure attached to it unrotatably to which the idler wheels are attached. Then there can be no rotating between the idler wheels. The sleeves and the idler wheels need not necessarily be attached as they will retain their controlled position because of the wires. The advantage of the arrangement according to the invention is that the movements of the carriage can be further adjusted for a certain feed beam, as desired, in such a manner that the carriage can be extend over the feed beam at its rear end and when required, at its front end in the required manner. Furthermore, when preparing feed beams of different lengths, one feed cylinder of a certain length can be used for feed beams of different lengths as the transfer movements can be measured in the required manner and therefore storing and investing costs and the costs for preparing spare parts will be reduced. Also, when using two wires both as feed and return wires, the feed and return forces will be symmetrical on the carriage 2. Additionally, the feed beam structure will be low as lower idler wheels can be used in it than in the prior art arrangements because the wires can travel in the elevation of the cylinders at the cylinders as they are placed at the sides of the cylinders. The invention is above in the specification
and in the drawings only shown by way of example and it is in no way bound to it . The order of the feed and return wires in the feed beam can be different as well as their way of attachment can vary in manners known per se. The slide pieces 2a of the carriage 2 can either be shorter than the length of the carriage or they can be situated so that they can partly slide over the ends of the carriage. The attachment of the piston rod 4a of the feed cylinder to the feed beam can be accomplished in several different ways. Moreover, even if the figures show an arrangement by way of example in which there are two of both feed and return wires, the invention can also be applied to those feed equipments in which only one feed wire and one return wire are used. The feed and return wires can be attached to the carriage in many ways. It is essential that the points of attachment of the wires are at a distance from one another so that the point of attachment of the end of the return wire is closer to the front end of the feed beam 1 and the point of attachment of the feed wire is closer to the rear end of the feed beam 1. Nor do the points of attachment need be as close as possible to the front and rear ends of the carriage but they can also be situated more in the centre of the carriage in its longitudinal direction, as long as the space between the points of attachment of the wires is suitable and the wires overlap in a suitable way at the carriage.