An indexing apparatus includes a casing, an indexing unit, a gripping unit, a dynamic unit and a driving unit. The indexing unit includes a connecting rod journalled in the casing and having a top portion extending out of the casing, an indexing disc sleeved rigidly on the connecting rod, and several circumferentially equidistant limiting devices provided along the periphery of the indexing disc. The gripping unit slides along the periphery of the indexing disc and can engage with one of the limiting devices so as to prevent the gripping unit from sliding relative to the indexing disc. The dynamic unit supplies power to the indexing unit. The driving unit transfers motion of the dynamic unit to the indexing unit so as to rotate the indexing disc. In a case where the gripping unit is engaged with one of the limiting devices, the movement of the dynamic unit disengages the gripping unit from the limiting device so as to rotate the indexing disc until the gripping unit engages with the next limiting device.
A turntable apparatus has a turntable in combination with an indexing mechanism for use in a universal machine tool. The turntable has a spindle, and a turntable driving system is provided for driving the turntable. A driving system is used for driving an indexing mechanism for separately driving the turntable, and has an indexing shaft. A first arrangement is provided for clamping the main spindle of the turntable, and a second arrangement is provided for clamping the indexing shaft of the indexing mechanism driving system. A backlash-eliminating arrangment is provided for eliminating backlash in each of the turntable driving system and the driving system for the indexing mechanism, so that the turntable can be rotated by the driving system to conduct indexing of the turntable in a condition where an output torque developed by the turntable driving system is limited to a relatively low level, and wherein, after positioning of the turntable, the main spindle of the turntable and an indexing shaft of the indexing mechanism driving system are clamped at the same time in a condition such that the backlash in each of the driving systems has been eliminated by the backlash-eliminating arrangement.
