RU2571118C1 - Method of rock percussion sawing and device to this end - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to mining, particularly, to production of construction materials, namely to sawing of the natural stone blocks. Claimed process comprises pressing of toothed saw to the rock for the saw to reciprocate and to deliver impacts at reciprocation. Note here that the saw is pressed continuously while percussion is effected onto the saw top, the percussion force and frequency are defined proceeding from the rock physical and mechanical properties. This invention discloses also the percussion tool.

EFFECT: accelerated separation of blocks from the massif or disintegration of blocks into plates-blanks, better quality of sawing.

3 cl, 4 dwg

Description

The invention relates to the mining industry, and in particular to the building materials industry, in particular to technological processes for the extraction and sawing of blocks of natural stone.

A known method of conventional sawing of rocks with gear saws. The essence of this method consists in sawing blocks from a rock mass of small strength and sawing these blocks into plates using saws, which are a hardened metal strip with cut teeth triangular or close to a triangular shape or with carbide cutting elements soldered into the saw body [1].

One of the options for this method of sawing was implemented manually with the help of sawing workers who reported the saw reciprocating motion and created the force of pressing the teeth of the saw to the bottom of the cut block [1]. Another modern version of the strip machine is that the reciprocating movements of the saw are created by a drive with a crank mechanism [1]. The path of the saw can be straight or curved. Rectilinear movements provide horizontal guides along which the saw rollers roll. Curvilinear motion can be created by various mechanisms. Vertical feed is carried out by means of a drive with pairs of "lead screw - lead nut" or chain feed integrated in the machine columns.

The main parameters of the working process of conventional rock sawing are: the speed and force of the reciprocating movement of the saw, the force of pressing the saw to the bottom of the cut. The workflow during conventional sawing is characterized by chipping and cutting the working surface of the rock due to the reciprocating movement of the saw.

The disadvantage of the method of sawing and sawing blocks using gear saws is that the working process occurs with very low productivity in medium-strength rocks and strong type of "marble" and "granite".

The closest in essence and the achieved result is a method of cutting stones with a gear saw, reciprocating along the cut and shock-vibrational movements directed normally to the cut, while in order to increase cutting efficiency, the frequency of shock pulses is measured with the speed of the blade so so that the impacts fall on the edge of the cleaved material from the previous impact [2].

The disadvantage of this method is the incomplete use of energy of shock loads due to the rebound of the saw from the bottom of the cut after striking. At the same time, the process of cutting the rock is interrupted, and its destruction occurs mainly due to chipping and chipping, which in turn requires an increase in impact energy and negatively affects the quality of the sawn surface.

The aim of the invention is to create a method for extracting blocks of natural stone, which allows to increase the yield of marketable products and reduce the costs of its subsequent processing, as well as to increase the speed of separation of blocks from the array or cutting blocks into slabs, especially for hard and ultra-hard rocks, by improving the quality sawn surfaces (reducing the number of cracks, punctures and chips) and increasing the speed of sawing while reducing the energy intensity of the work process.

The task is achieved by combining the sawing process with a constant clamping of the saw to the bottom of the cut and impact destruction of rocks.

This happens as follows, a saw making reciprocating movements in the sawed rock is continuously pressed to the saw with the help of special devices, for example, screw-nut gear, or pneumatic cylinders or hydraulic cylinders, or the dead weight of the structure, adjustable by counterweights, while simultaneously striking the top saws with a certain frequency and force, for which they use a percussion device. The shock waves generated by the device pass into the saw blade, saw teeth and then into the rock. To achieve the best result, the force of strikes is chosen based on the physicomechanical properties of the sawed rock. At the same time, three processes of rock destruction occur together: puncturing the working surface of the rock due to shock loads, chipping and cutting the working surface of the rock due to the reciprocating movement of the saw. The continuity of the pressing of the saw to the cut leads to an increase in the number of shock waves passing into the rock and, as a consequence, to the formation of a stable compaction zone, which provides a sharp increase in the efficiency of the destruction process and allows to increase the sawing speed of rocks.

Thus, the main parameters of the impact sawing working process are: impact energy and impact frequency of the impact device, the speed and force of the reciprocating movement of the saw, the force of pressing the saw to the bottom of the saw. Moreover, the energy intensity of the impact sawing process is lower than that of the stone cutting method and the conventional sawing method described above, and the productivity is higher.

Due to the fact that the shock waves generated by the saw body in cross section have small scattering when passing from the teeth into the destructible rock in the contact zone, the formation of side cracks is sharply reduced, which makes it possible to obtain more even surfaces when sawing a block or plate-workpiece, which positively affects the quality of workmanship and increases the yield of finished products.

The impact sawing method can be carried out by using the following device shown in FIG. 1, 2, 3.

The basis of the design of the device for sawing rock blocks is a frame 1 mounted on supports 2. A vertical feed mechanism 3 is attached to the frame, which moves the beam 4 along the guides 5. A horizontal feed mechanism 6 is located on the beam, which informs the reciprocating movement of the impact unit 7 , and moving along the guides of the beam 8. The shock assembly includes a shock device 9, which serves to generate shock waves, which after impact pass into the waveguide 10, then into the gear saw 11. Between in the waveguide and a saw for better passage of shock waves it is advisable to install an adapter 12, which is loosely attached to the top of the saw. The saw is mounted on the stops 13 attached to the traverse, and is fixed non-rigidly by the latches 14.

The design of the device for cutting blocks of rock from the array 25 (Fig. 3) is characterized in that the horizontal feed is carried out by reciprocating the roller carriage 20 along two I-rails 21 using the drive 18 with the feed mechanism 19. The guides 21 are equipped with travel stops 22 and mounted on a ledge quarry. On the carriage 20 there are two racks 23, to which the frame 1 of the impact sawing device is attached. The impact unit with a saw can also carry out the workflow in a horizontal plane and carry out horizontal cuts. In this case, horizontal feed will be carried out using mechanism 3.

To ensure the process of clamping the saw to the bottom of the cut, a screw-nut transmission 3 can be used (Fig. 1), or pneumatic cylinders or hydraulic cylinders 3 (Fig. 3), or the dead weight of the structure, adjustable with counterweights 17 (Fig. 2) .

The device operates as follows. Using the vertical feed mechanism, the saw is moved to the upper position (position 1 in FIGS. 1 and 3). Under the saw on the working platform 15, the saw block 16 is installed, then the saw with the shock assembly is lowered until it contacts the saw block. In the case of cutting blocks on a quarry, the saw is installed on the marked line of the cut of the horizontal or vertical platform of the ledge. After performing this operation, sawing is performed until the formation of a cut. To do this, first turn on the percussion device 9, then turn on the horizontal feed mechanism 6 (Fig. 1 and 2) or 18 and 19 (Fig. 3), which tells the reciprocating movement of the impact unit 7 with the saw 11. The frequency and energy of the impact of the device at the beginning workflow should be minimal, but sufficient for the formation of quality cut. Also, before the working process along the line of the future cut, to prevent the saw from deviating from the vertical position, limiters not shown in the figures are installed. Also, the design of the device may include guides 24 in the form of guides (Fig. 3), preventing various deviations of the saw. After the formation of the cut, the percussion device is transferred to the operating mode, calculated on the corresponding physical and mechanical properties of the sawed rock. At the final stage of the block sawing process, the frequency and impact energy of the device are reduced in order to prevent the formation of a large main crack.

An impact assembly may include one or more impact devices and, accordingly, may be single or multi-module. The number of percussion devices and their position depend on the length and height of the working body (saw) and is calculated by the formula

Where

where N _beats is the estimated number of percussion devices (rounded to the nearest larger integer value); L _saws , N _saws - respectively the length and height of the saw, m; L _1UD - the area of action of one percussion device along the length of the saw, m (see Fig. 4); α _1ud - the angle of scattering of the shock wave in the saw body along the length, α _1ud = 36 °; Δα _1ud - deviation of the angle α _1ud from the average value, Δα _1ud = ± 3 °. The obtained value of N _{beats is} rounded to the nearest larger integer value. In FIG. 4 are designated by numbers 11 - a gear saw, 9 - a percussion device. The distance between adjacent shock nodes should be no more than L _1ud . The distance from the edge of the saw to the nearest impact unit should be no more than L _1ud / 2.

Using the proposed method and device can improve the performance of the operation of sawing from an array of medium-strength blocks, strong and extremely strong rocks, as well as sawing these blocks into thick plates. At the same time, good quality of the side faces is obtained, they practically do not form cracks during the operation. This circumstance is especially important when cutting blocks of valuable (rare) breeds.

The invented method can be applied, for example, in the quarry of the Kalguvara granite deposit when sawing granite blocks from massifs and at the Moscow stone processing plant in the city of Dolgoprudny, Moscow Region, when sawing granite blocks into blanks.

The volume of mined blocks in the quarry is from 1 to 8 m ³ , which corresponds to I, II and III classification groups.

The presence of steeply declining systems of cracks in the field is a determining factor for choosing the direction of advancement of the front of mining operations - from south to north, and during mining, from east to west.

Granites of the Kalguvara deposit are characterized by a high compressive strength of the order of σ _sr = 145-150 MPa.

At the Kalguvara quarry, sawing equipment is located on the horizon with a mark of +173 m. Before starting cutting operations using a shock saw, a working ledge with a slope angle of 90 ° is prepared using a blasting method. The height of the ledge is 1.4-2.4 meters, depending on the required block height. The upper and lower platforms of the ledge should be aligned in order to place the necessary equipment for operation on them. The width of the site on the lower and upper ledges for equipment should be at least 7-8 meters, length - at least 14-15 meters. On it are located: a shock sawing device, compressor or pump (depending on the type of energy used) with hoses.

To implement the process of sawing blocks of rock from the massif, 2 sets of impact sawing devices are used with equipment providing the working process. The first set is located on the lower ledge, the second - on the upper.

Technological operations are performed in the following sequence. The device, located on the lower ledge, performs a horizontal cutting cut at the bottom of the ledge. Then the device located on the upper ledge performs vertical transverse and longitudinal cuts.

The drive of the impact sawing device can be fully pneumatic and operate from a compressor station or pneumoelectric, i.e. the compressor feeds the percussion device and pneumatic cylinders to feed the saw, and the diesel generator - the system of reciprocating movement of the saw.

The application of this technology allows to increase the yield of commodity blocks by at least 20% with respect to the drilling and blasting method currently used in quarries, and by 5-10% with respect to impact-cutting machines (channelers). In addition, the cost of giving the product blocks the correct geometric shape before further processing is reduced.

INFORMATION SOURCES

1. Sychev Yu.I., Berlin Yu.Ya. Sawing up a stone. - M.: Stroyizdat, 1989, p. 6, p. 63, p. 128.

2. Copyright certificate of the USSR No. 105819 A1, 1957. (prototype).

Claims (3)

1. The method of impact sawing, including pressing the gear saw to saw the rock, making the saw reciprocating and striking during the movement of the saw, characterized in that the pressing of the saw is carried out continuously, and the blows are applied to the upper part of the saw, with the force and frequency impacts is determined from the physico-mechanical properties of the sawn rock. 2. A device for impact sawing, including a gear saw equipped with a mechanism for reciprocating movement, impact mechanisms and a frame with the saw pressed to the sawed block, characterized in that for ensuring the continuity of pressing the saw to the bottom of the saw cut of the sawed block, use the gears built in the frame “Screw-nut”, or pneumatic cylinders or hydraulic cylinders, or dead weight of the impact unit, adjustable by means of counterweights, and for better transfer of impact energy from the impact device to the saw use a waveguide with an adapter that is loosely attached to the top of the saw. 3. The device according to p. 2, characterized in that the number of percussion devices and their location depend on the length and height of the working body (saw) and is calculated by the formula

Where

where L _saws , H _saws - respectively the length and height of the saw, m; L _1ud - the area of action of one percussion device along the length of the saw, m; α _1ud - the angle of scattering of the shock wave in the saw body along the length, α _1ud = 36 °; Δα _1ud - the deviation of the angle α _1ud from the average value, Δα _1ud = ± 3 °; in this case, the obtained value of Ν _{beats is} rounded to the nearest larger integer value.

Images