Also it is important that the turret -be accurately located and locked in indexed position. The present invention contemplates an indexing mechanism for an indexible turret of a machine tool wherein the operator can initiate the indexing movement of the turret in either direction and Without further attention from the operator the indexing movement of the turret automatically will stop after the turret has been indexed one station and the turret will be accurately located and locked in its indexed position at the new station. The invention also contemplates an indexing mechanism such that the operator can cause the turret to so index in either direction through a plurality of successive indexing stations. The invention includes the provision of an indexing mechanism for the indexible turret of a machine tool wherein the indexing movement of the turret is eifectedby a power operated rotatable indexing cam with said cam also controlling the unlocking and the locking and locating,v of the turret in indexed position relative to the slide or member which carries the turret. The invention also includes providing the slide or member which carries the turret with an upwardly facing annular toothed coupling element and the turret with a downwardly facing similar coupling element, with the teeth of said elements interengaging and functioning to accurately locate and lock the turretin each indexed position. The rotatable indexing cam is provided with a cam groove that Aeifects a raising of the turret to disengage the teeth of said coupling elements and unlock the turret for indexing movement and for lowering the turret to interengage the teeth of said elements and accurately locate and lock the turret in indexed position.

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The turret saddle and auxiliary slide. Bed The bed is a long box like casting provided with accurate guideways upon which are mounted the carriage and turret saddle. The bed is designed to ensure strength, rigidity and permanency of alignment under heavy duty services. Headstock The headstock is a made up of large casting. It is located at the left-hand end of the bed. The different types of headstocks in capstan and turret lathe are as follows: Step cone pulley driven headstock.

Direct electric motor driven headstock. All geared headstock. Preoptive or preselective headstock. Only three or four steps of the pulley can cater to the needs of the machine. The machine requires special countershaft unlike that of an engine lathe, where starting, stopping and reversing of the machine spindle can be affected by simply pressing a foot pedal. Any speed difference or reversal is achieved by directly controlling the motor.

Three or four are available and the machine is suitable for smaller diameter of workpieces rotated at high speeds. The speed changing has done by without stopping the machine. For different operations and for turning different diameter, the speed of the spindle must change. The required speed for the next operation is selected beforehand and the speed changing lever is placed at the selected position. After the first operation is complete, a button or a lever is simply actuated and the spindle starts rotating at the selected speed required for the second operation without stopping the machine.

This novel mechanism is affected by friction clutches. Cross-slide and saddle In small capstan lathes, hand-operated cross slide is used which are clamped on the lathe bed at the required position. The larger lathes and heavy-duty turret lathes are equipped with usually two designs of the carriage.

Conventional type carriage Side hung type carriage 3. The design facilitates swinging of larger diameter of the workpiece without being interfered by the cross slide. The saddle and the cross slide may be fed longitudinally or crosswise by hand or power. The longitudinal movement of each tool may be regulated by using stop-bars or shafts set against the stop fitted on the bed and carriage. These stops are set so that each tool will feed into the work to the desired length for the purpose of duplicating the job without checking the machining length for different operations each time.

These stop the first trip out the feed and then serve as a dead-stop for small head operated movement of the tool to complete the cut.

The stop bars are indexed by hand to synchronise with the indexing of the tool. The tools are mounted on the tool post and correct heights are adjusted by using a rocking or parking piece.

The turret saddle and auxiliary slide In a capstan lathe, the turret saddle bridges the gap between two bed-ways, and the top face is accurately machined to provide a bearing surface for the auxiliary slide. The saddle is adjusted on lathe bed-ways and clamped at the desired position.

The hexagonal turret is mounted on the auxiliary slide. In a turret is directly mounted on the top of the saddle and any movement of the turret is affected by the movement of the saddle. The movement of the turret may be effected by hand or power. The turret is a hexagonally shaped tool holder intended for holding six or more tools. Each face of the turret is accurately machined.

Through the centre od, each face accurately bored holes are provided for accommodating shanks of different tool holders. The centre line of each hole coincides with the axis of the lathe when aligned with the headstock spindle. In addition to these holes, there are four tapped holes on each face of the turret for securing different tool holding attachments. At the centre of the turret on the top of it, there is a clamping lever which locks the turret on the saddle.

Six stop bars mounted on the saddle which restricts the movement of each tool mounted on each face of the turret to be fed to a predetermined amount for duplicating workpiece. After one operation is completed, as the turret is brought back away from the spindle nose, the turret indexes automatically by a mechanism incorporated on the bed and in turret saddle, so that the tool mounted on the next face is aligned with the work. Download Pdf of this article That is it, thanks for reading.

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Indexing (motion)

Without indexing capability, all manufacturing would have to be done on a craft basis, and interchangeable parts would have very high unit cost because of the time and skill needed to produce each unit. In fact, the evolution of modern technologies depended on the shift in methods from crafts in which toolpath is controlled via operator skill to indexing-capable toolpath control. A prime example of this theme was the development of the turret lathe , whose turret indexes tool positions, one after another, to allow successive tools to move into place, take precisely placed cuts, then make way for the next tool. How indexing is achieved in manufacturing[ edit ] Indexing capability is provided in two fundamental ways: with or without Information technology IT. Non-IT-assisted physical guidance[ edit ] Non-IT-assisted physical guidance was the first means of providing indexing capability, via purely mechanical means. It allowed the Industrial Revolution to progress into the Machine Age. It is achieved by jigs , fixtures , and machine tool parts and accessories, which control toolpath by the very nature of their shape, physically limiting the path for motion.


Difference Between Capstan and Turret Lathes

Types[ edit ] There are many variants of the turret lathe. They can be most generally classified by size small, medium, or large ; method of control manual, automated mechanically, or automated via computer numerical control NC or computer numerical control CNC ; and bed orientation horizontal or vertical. Archetypical: horizontal, manual[ edit ] In the late s a "capstan lathe" with a turret was patented in Britain. The term "turret lathe" without further qualification is still understood to refer to this type. The formative decades for this class of machine were the s through s, when the basic idea of mounting an indexable turret on a bench lathe or engine lathe was born, developed, and disseminated from the originating shops to many other factories.

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