Abstract: A support for a reciprocating ram wherein a plurality of rollers having angularly related generally cylindrical support surfaces are mounted in a fixed location and the ram is provided with planar surfaces having the same corresponding angular relationship wherein the weight of the ram is utilized to maintain the planar surfaces in contact with the generally cylindrical support surfaces during reciprocal movement of the ram with dampening means being provided to minimize vibrations. An additional force is applied to the ram to ensure a rolling relationship between the planar and generally cylindrical surfaces at all times during the reciprocal movement.

Abstract: In a monitoring system for the gates of a mine lift shaft, each gate has a switch and a square wave is generated in a signal station and connected to a transistor inverter beyond each switch. When the switch is in the closed (safe) position, the transistor inverter is connected in circuit and the inverse of the waveform is transmitted back to the signal station. When the switch opens the transistor is shorted out and thus the returned waveform is in phase with the transmitted waveform. The various conditions which may be received at the signal station are detected and only if the switch and cable are operating correctly is the gate closed condition indicated. The use of a square wave and a changeover switch ensure that both conditions of the switch produce a definite signal at the signal station, thus any failure in the cable or switch prevents the received waveform from being the inverse of the transmitted waveform.

Abstract: A lightweight metallic container is disclosed and claimed having a side wall and an effective rigid bottom wall integral therewith. The side wall and bottom wall merge to define a first inclined face, the inclined face forming an angle of between about 35.degree. and 45.degree. with respect to the axis of said container, a tapered member is provided and is integrally formed at the juncture of the side wall and inclined face, the member having a taper angle in a given range and a given wall taper thickness, an annular surface integrally connected to the first inclined wall for supporting the container, a second inclined face integrally connected to the annular surface, and a curved panel integrally connected with the second inclined face. The curved panel is so formed that it has a radius of curvature greater than the diameter of the annular surface. The height of the second inclined face is less than half the height of the first inclined face.