Abstract: A transmission device in which planetary gears are disposed on the periphery of a sun gear so that each planetary gear can effect gear transmission and can revolve around the sun gear, and in which an internal gear wheel is disposed so as to wrap round the planetary gears so that the planetary gears can effect gear transmission in association with the internal gear wheel. A sun roller coaxial with the sun gear and capable of freely rotating independently of the sun gear is provided, and planetary rollers are also provided with being respectively coaxial with the planetary gears, freely rotatable independently of the same and having a rolling contact with the sun roller. An outer ring is disposed around the planetary rollers and has a rolling contact with the planetary rollers.

Abstract: An automatic tool-replacement apparatus including the main body of a machine tool on which a plurality of tools can be dismountably mounted. The tools are selectively held by an automatic tool-replacement arm and are mounted on or dismounted from the main body. The arm has a plurality of holding portions for holding the tools. Therefore, a plurality of tools can be mounted on or dismounted from the main body of the machine tool by one-time operation of a single arm. Each holding portion has a pawl for preventing disengagement of the tool positioned therein, this pawl being able to advance toward and retract away from the holding portion.

Abstract: A tapper for loading a spindle of machine tools with a tap. The tapper proper has a shaft to be driven, which is supported under floating axially by means of a pair of springs the pressurizing direction of which are opposite to each other, built-in. Cutting oil is pressurized to be fed from the outside of the tapper proper through oil passages, respectively which are provided on the tapper proper and the shaft to be driven to a oil hole and, in that case, the oil passages are formed such that the resultant hydraulic pressure does not give rise to an action of breaking the floating state of the shaft to be driven.

Abstract: A tool holder assembly which comprises a tool holder adapted to be connected with a machine spindle for rotation together therewith, a stationary support member for rotatably supporting the tool holder and adapted to be connected to a fixed portion of the machine, a fluid supply circuit defined in the tool holder for the supply of a cutting fluid from an external source thereof towards a fluid discharge passage defined in a machine tool replaceably carried by the tool holder, and a vane-type displacement pump for forcibly pumping the cutting fluid from the fluid supply circuit to the fluid discharge passage in the machine tool for pouring the cutting fluid onto the workpiece being machined by the cutting tool. The displacement pump has its rotor constituted by a portion of the tool holder, and a pump casing constituted by a portion of the stationary support member.