584,943. Mining-machines. MAVOR & COULSON, Ltd., and SPROUL, J. C. June 8, 1944, No. 10983. [Class 68 (i)] In a mining-machine having a shearing cutter of the cutter chain type, the chain-guiding frame comprises a lower longitudinal element fixed to the machine, an upper longitudinal element which is raised or lowered'to vary the height of cut, and a front linkage connecting said elements, means being provided for adjusting the upper element through a range of positions and moving said linkage to maintain constant the length of the chain path. As shown, the shearing cutter frame comprises upper and lower members A, B pivoted at 1. and forward toggle members C, D, a strut 11 pivoted to toggle member D bearing against a block 7 to limit straightening of the toggle linkage. The block 7 is adjustably held by a pin 10 passed through any of series of holes 8, 9 in the member B and block 7 respectively, the holes of the two series being differently spaced. The cutter chain is tensioned by a screw 12 journalled in a bar 13 fixed between the sides of the member B and engaging a nut 14 secured to the machine body M, the member B being then secured by threaded pins 15; bar 13 also holds the members A, B in the same plane. The block 7 may be omitted, the strut 11 then being adjustably pinned to the frame member B. In another form, a screw jack is provided between frame members A, B for adjustment.
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