machines for cutting piece stone from rock masses.
Stonecutting machines mine wall stone, large wall blocks, and block stock (in quarries and more rarely in mines); these are cut into facing slab and other architectural and structural articles. Stonecutting machines have a rigid self-propelled frame that in most models moves along tracks. Mounted on the frame are the drives for rotating the cutting tools and for moving the machine. The cutting tools of stonecutting machines are circular saws, ring cutters, and chain and rod cutters equipped with hard-alloy teeth. Stonecutting machines are differentiated by use (for quar-riers and undermines), type of product obtained (wall stone and large blocks), cutting depth (short cut up to 0.42 m and long cut up to 3 m), and the extent of combination of the operations. There are single-operation units, units that are an aggregate of single-operation machines unified by a common drive and control, and universal stonecutting machines that perform three operations (cross, horizontal, and butt cutting).
Rope saws are a separate category of machine: these are designed for sawing out large blocks of hard limestone and marble. Specifications of the stonecutting machines widely used in the USSR can be found in Table 1.
|Table 1. Stonecutting machines produced in the USSR|
|1 The higher productivity applies to the lower stone strength and vice versa. 2 Also used for cutting marble blocks with a compression strength up to 0.12 giganewtons per sq m (1, 200 kilograms-force per sq cm)|
|Machine type||Maximum strength of stone in compression (meganewtons/sq m [kilograms-force/sq cm])||Type of cutting tool||Cutting depth (m)||Rated power (kilowatts)||Weight (tons)||Productivity for bulk rock (cu m/year )1|
|Quarries: machines producing wall stone|
|SM-89A...........||10 (100)||Circular saw||0.42||35.3||10.1||42, 000–14, 200|
|SM-89AU...........||25 (250)||Same||0.42||52||14||45, 500–23, 600|
|SM-824...........||3.5 (35)||Same||2.9||127||42||109, 000–68, 000|
|KM-4M...........||5 (50)||Same||2.31||16.8||2.8||15, 000–4, 000|
|Quarries: machines producing large blocks|
|SM-580A...........||40 (400)||Ring cutter||0.86–1.04||51.5||16.2||34, 600–15, 000|
|SM-580M...........||40 (400)||Same||0.86–1.04||47.5||16.6||38, 400–16, 400|
|SM-177A...........2||40 (400)||Same||0.86–1 04||21.7||9.4||13, 600–6, 000|
|KMAZ-188...........||5 (50)||Chain cutter||2.85||10.5||1.4||6, 500–4, 900|
|KMG-2...........||10 (100)||Circular saw||2.35||16.8||2.3||7, 900–2, 900|
The stone is cut out of the rock mass by three cuts made in sequence: cross, horizontal, and vertical (butt). The last of these separates the stone from the solid bed. In a majority of stonecutting machines, the second and third operations are performed simultaneously with the longitudinal movement of the machine along the cut.
The development of stonecutting machines has included the creation of designs incorporating maximum rationalization of operations, improvement of cutting tools, mechanization of the removal of wastes and removal and stacking of products, standardization of basic assemblies and parts, and automation of control. The mechanized production of sawn wall stone (such as limestone and tuffs) has developed rapidly in the USSR. Production, which was 1 million eu m in 1940 and 2.5 million eu m in 1950, had climbed to 13.16 million eu m by 1971.
REFERENCESGal’perin, M. I„ and V. D. Abezgauz. Mashiny dlia rezaniia kamnia, 2nd ed. Moscow, 1964.
Rodin, B. M. Kar’ery pil’nogo kamnia. Kiev, 1964.
B. M. RODIN