Abstract: A double surface machining system for machining both side surfaces of a workpiece comprises, in an operational state, a pair of upper and lower spindle heads to be vertically positioned and driven, respectively, a pair of upper and lower spindles provided for the upper and lower spindle heads, respectively, in parallel to each other, to be rotatable about horizontal axes thereof, the upper and lower spindles having front ends to which tools are mounted, respectively, a pair of upper and lower workpiece supports for supporting the workpiece therebetween, which are vertically positioned and driven on one side of the upper and lower spindle heads as viewed from a workpiece feed direction, respectively, and another pair of upper and lower workpiece supports for supporting the workpiece therebetween, which are vertically positioned and driven on another one side of the upper and lower spindle heads as viewed from a workpiece feed direction, respectively.

Abstract: In apparatus for driving a spindle of a machine tool, the spindle being rotatably supported in a spindle housing and received in a took mounting opening adapted to be inserted with a pull stud at a front end thereof, including a took clamping drawbar provided with a collet for clamping the pull stud at a front end of the drawbar, and a device for axially moving the drawbar, there is provided a device interposed between the inner surface of the spindle and the outer periphery of the drawbar for transmitting a torque from the drawbar to the spindle. The drawbar is connected to a source of drive of the spindle.

Abstract: In a hydrostatic pressure worm-rack device of the type comprising a worm formed with operating oil supply opening at the opposite flanks of respective teeth of the worm, opposite flanks of respective teeth of the rack being formed with oil pockets, there are provided an oil distributor mounted on one end of the worm shaft for supplying oil to mating surfaces and not mating surfaces of the teeth of the worm and rack and for supplying pilot oil to pilot oil supply ports provided for the flanks of the teeth at the opposite ends of the worm which firstly mate with the teeth of the rack.

Abstract: An automatic pallet changer for replacement of pallets automatically between a pallet magazine storing a plurality of pallets and a pallet table of a machine tool which comprises a rack fixed on the rear of each pallet, a pallet driving pinion engaging with the rack disposed on a side end of the pallet table and a pinion driving apparatus. The pinion is driven to rotate and the rack is moved linearly whereby the pallet is transferred to and from the table of machine tool.

Abstract: An attachment for fitting a tool to a hollow spindle of a machine tool, in a case where a shank portion of the tool has a taper-size smaller than that of a tapered hole of the spindle, comprises a hollow attachment body to be secured to the lower end of a ram of the machine tool, a sleeve rotatably supported in the attachment body, and an arbor assembly disposed axially movably in the sleeve. The arbor assembly comprises a stud arbor, a pull-stud to be engaged with a collet chuck disposed in the spindle, and a collet chuck to be engaged with a pull-stud of the tool inserted into a tapered hole of the sleeve.