Abstract: A two-spindle machine tool having a fixed first headstock with a main spindle extending in a direction Z and with a chuck, and two tool heads with turrets further has a movable second headstock with a main spindle extending in the direction Z and with a chuck, the second headstock and the two tool heads being supported on respective slide mechanisms which enable them to move in the direction Z and also in a direction X perpendicular thereto relative to the first headstock, and which are so positioned as to enable the two headstocks and two tool heads to function in respective operational regions enabling machining tools held by the turrets to perform various modes of machining including independent but simultaneous machining of respective workpieces held in the two chucks and simultaneous or successive machining of a single workpiece held by either of the chucks.

Abstract: A rotatable member to be indexed in a machine is intermittently rotated through specific angular displacements between predesignated indexing positions by an indexing mechanism driven by a hydraulic motor and is positively locked in each indexing position by a positive clutch coupling comprising a movable plate fixed to the rotatable member and a mating stationary plate fixed to a stationary part of the machine, the clutch coupling being engaged and disengaged by a hydraulic cylinder. The hydraulic motor and hydraulic cylinder are controllably and coordinately operated by a common hydraulic system including pipe and tank lines and at least one electromagnetic changeover valve of the two-position, four-connection type.

Abstract: In an indexing system for a member such as a turret head of a lathe, in which the member after undergoing an indexing movement is locked by a locking bolt thrust by spring force into a bolt hole in a plate coaxially fixed to the member, a hydraulic cylinder is used to exert a great force for holding the locking bolt positively and unmovably in each bolt hole against any reactive counter force from the side of the member due to a great load. The hydraulic cylinder is controllably actuated by a single hydraulic system containing also a hydraulic motor for driving the member in its indexing movement and a solenoid valve.

Abstract: A machining center comprises a horizontal bed, a column disposed perpendicularly to the bed, a plurality of slide rest located to be relatively movable to the bed and column, a spindle head, and a tool magazine. The spindle head includes vertical and horizontal spindles and a tool exchanging mechanism comprising tool exchanging arm assemblies positioned at positions suitable for the corresponding spindles and adapted to exchange tools held by the tool magazine with those held by the vertical and horizontal spindles.

Abstract: In an apparatus for automatically feeding bar stock material into a numerically-controlled automatic lathe, a bar is rotatably clamped and borne by the clamp jaws of several bearing clamps disposed in a row at intervals along the bar and orientated at respectively different angles about the bar, each clamp jaw comprising three pulleys in triangular formation and an endless belt supported on these pulleys, one of which is driven, the bar being clamped between a span of the belt between two pulleys of one jaw and that of the other jaw of each bearing clamp. The bar is thus held at clamping positions that vary helically about the bar as it is fed by a feed pipe into the lathe.

Abstract: In a machine tool having a horizontal, hollow main spindle having therein a main chuck for gripping a bar stock and confronting at a front thereof a machining zone, into which the forward end of the bar stock is intermittently fed through the main chuck from the rear for every cycle of machining by a selected tool mounted on a tool support structure on feed slides and brought into the machining zone to carry out machining of the bar stock, a bar end support engages and supports the forward end of the bar stock at the start of each intermittent feeding thereof and stably guides the same fully into position for machining, unrelatedly to the rotation of the main spindle, whereby the cyclic bar feeding and machining operation can be continuously carried out without stopping the main spindle. Means are provided whereby bar stocks of circular cross-sectional shape and any shape other than a circle can be thus machined.