GB2208107A - Revolving tool-carrier turret - Google Patents

Description

2 12' 0 8 ' i 0 '7 REVOLVING TOOL-CARRIER TURRET This specification

relates, as its title indicates, to a revolving tool-carrier turret of the kind used on turret lathes, comprising a member which holds various tools and is associated with a shaft adapted to be displaced angularly to position the different tools as required by the work to be performed.

Tool-holding devices of the above kind are known which include a base member incorporating the shaft of the tool-holding member, and a clutch member adapted to unlock and lock these two elements, rotary means being provided which enable the axis to be rotated in its unlocked position, and also means for positional control.

To effect the locking and unlocking as between the tool-holding member and the base member, the outer walls of both members have facing machined zones or rings; the clutch member is always connected to the shaft, which it moves upwards to disengage the two rings, returning the shaft to its position when the rotation has been performed to change the tool placed in the operating position. This arrangement is disclosed, for example, in British Patents Nos. 1 025 019, 1 512 120 and 1 525 430.

The arrangement of the rings on the outside and the displacement of the shaft and therefore of the tool-holding member have various disadvantages, the most serious one being that the rings are exposed to all kinds of chippings, so that their teeth continuously deteriorate, the result not being merely inaccuracy in the angular position determined by the coupling of the teeth, but also in the long run as a rule their partial or complete destruction.

Spanish utility model No. 265 326 in the name of the Duplomatic Company, with priority of an ltalian Application, claims another revolving toolcarrier turret having an arrangement which is similar, except for the outward movement of the shaft with a series of catches interposed between the tool-holding member and the base member. Basically this arrangement offers greater safeguards against the penetration of chippings, but there can-be no doubt that if they reach the catches they not only destroy them, but also impede or render impossible the rotation of the tool-holding member.

Moreover in these prior art arrangements the shaft associated with the tool-holding member is rotated by a complicated gearing mechanism actuated by an electric motor, something which causes large bulk, so that as a rule the tool-holding apparatus as a whole weighs more and must move over guides disposed on a axis radial in relation to the machine axis in order to act on the piece.

The apparatus according to the invention has obviated all these disadvantages, since the clutch member comprises an annular gear on its face opposite the outer partition, formed by two concentric rings disposed on the base member and on the shaft respectively, so that when it moves inwards the clutch member unlocks the shaft, which rotate freely, while when it moves outwards it brings the two concentric rings together and therefore immobilizes the shaft in relation to the base member. There is therefore no need for the shaft to make any kind of movement outwards in order to achieve its angular displacement.

The clutch member is so actuated axially by a hydraulic circuit that the shaft of the tool-post can readily be kept disconnected from the base member; since no kind of outward movement must be made, it can be mounted on bearings, thus making available an auxiliary tool mounted on its own shaft, by which other machining operations can be performed, such as the production of orifices or similar operations.

The invention also comprises other innovations in the rotary device which enable the shaft to make an angular rotation; such means in this case comprise a hydraulic motor, means also being provided for controlling angular position to determine the precise position which must be occupied by the shaft for a particular tool to be in the operative position.

Before giving a description of the invention, it should be pointed out that it is not strictly limited to the precise details of the description, which must therefore be regarded as purely illustrative and non-limitative.

A clearer idea of the subject matter of the invention can be gathered from the following description of a preferred embodiment of the invention with reference to the accompanying merely exemplary diagrammatic drawings wherein:

Fig. 1 is a section through a central vertical plane of the base member (1) of the tool-post.

Fig. 2 is a side elevation of the turret, partially sectioned through a plane in front of the location of the disc (13), and Fig. 3 shows a detail of a proximity-detecting device located at the rear of the wheel (10).

i i 1 The revolving tool-carrier turret of the preferred embodiment comprises a member (not shown) which holds the tools and is associated with a shaft (2) mounted to rotate inside a base member (1) incorporating a clutch member (5) adapted to lock and unlock the two members; rotary means enable the shaft to be rotated, and means for angular positional control are also provided.

The shaft (2) has an annular gear (4) disposed towards the inside, while the base member (1) has another ring (3), concentric with the gear (4) and similarly arranged. A clutch wheel (5) has a ring (6) which is larger than the two previous rings and has a plurality of radial teeth disposed on its face opposite the aforementioned rings (3 and 4).

The clutch member (5) has a radial extension (towards the right in the drawing), while the base member (1) bounds a chamber (7) having on both sides of such extension inlet/outlet ducts (8 and 9) for hydraulic fluid. When the duct (8) is connected to the pressure circuit, the clutch member (5) is moved to the right and therefore disengages the concentric rings (3 and 4), so that the shaft (2) can rotate in relation to the base member (1); if, on the other hand, the fluid reaches the chamber (7) through the duct (9), the member (5) is displaced outwards and the annular gear (6) associated therewith brings the facing rings (3 and 4) together and therefore immobilizes the shaft (2) in relation to the base member (1).

Clearly, the clutch member (5) has sealing means both for its central aperture through which it can move axially along the shaft (2), as on the outer edge of the expansion included in the chamber (7), which is defined by an intermediate member included in the main bore of the base member (1).

"o The shaft (2) is rotated by a wheel (10) disposed in a rear chamber and always connected to the shaft of the tool-holding member. The wheel (10) forms the planet wheel for a transmission whose carrier pinion (11) is associated with a hydraulic motor (12) mounted at right angles above the base member. The unlocking of the shaft and the energization of the motor (12) enables the shaft to be rotated into predetermined angular positions by a locking device which will be described hereinafter.

Fig. 2 shows, in conjunction with Fig. 1, a disc (13) disposed on the outer face of the toothed wheel (10); the disc is formed with a plurality of notches disposed along its periphery in angular positions determined by the position of the various tools in the corresponding outer tool-holding member. Disposed tangentially to the disc (13) is an electromagnet (16) or similar device whose rod (17) acts on the disc, being introduced into the corresponding groove in order to enable the required angular position to be precisely determined, thus preventing the workpiece from being slightly in front or slightly behind, so that machining faults take place.

Fig. 3 shows an alternative method in which the wheel (10) has various detection elements (18) which, matching the pair (14) disposed immovably in the rear cover (15), allow the determination by means of a proximity device of the position of the wheel (10) and therefore of the position of the shaft and the tool-holding member.

This device for locking in angular positions allows the precise establishment of the point at which the facing rings (3, 4 and 6) must be coupled, the result in all cases being extreme accuracy, which not only allows the optimum operation of the tool being used, but also prevents - 6 possible errors in machining, including the breaking of the tool due to inadvisable use.

Since in any case the shaft (2) performs no axial displacement, it was thought possible to include in a zone of the shaft a pinion (20) receiving the transmission of an auxiliary motor by means of which when the shaft is unblocked it can be rotated at speeds suitable for machining. At the same time, the frontal zone of the shaft is formed with a hollow or some other means of coupling a tool, such as a drill or the like, which when actuated by the auxiliary motor can perform further machining operations which the lathe cannot perform in normal operating conditions.

As can be seen from the drawings, the result is a compact tool-holding block in which no elements stand out, and the shaft is retained in the identical position, whether locked in relation to the member or not, so that there is no possibility of chippings getting into the inside of the toolholding member. The hydraulic rotary motor allows inter alia quieter operation and, in conjunction with the devices for locking in predetermined angular positions, enables such precision to be determined very accurately.

of course, an engineer in the art can make various modifications both as regards the material and the embodiments which have been disclosed merely by way of non-limitative examples without exceeding the scope of the invention.

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Claims (6)

1. A revolving tool-carrier turret which comprises a tool-holding member associated with a shaft rotatably mounted on a base member and incorporates a clutch member adapted to lock and unlock the two members, means being provided for rotating the shaft in its unlocked position and also means for angular positional control, characterized in that the clutch member has an annular gear on its face opposite the outer partition, defined by two concentric rings mounted on the base member and on the shaft of the tool-holding member respectively, and has a radial extension matching a chamber in the base member having inlet/outlet ducts which, when connected to a hydraulic circuit, enable the clutch member to be displaced axially and therefore enable the shaft and the base member to be coupled and uncoupled without axial displacement of the shaft.

2. A revolving tool-carrier turret according to claim 1, characterized in that the base member has a second open chamber which receives a wheel, always connected to the shaft of the tool-holding member, which forms the planet wheel of a transmission whose carrier pinion is associated with the shaft of a hydaulic motor mounted at right angles above the base member, by means of which when the shaft is unlocked it can be given a rotation for placing the suitable tool in position.

3. A revolving tool-carrier turret according to claims 1 and 2, characterized in that the planet wheel is associated with a can or disc formed with angular notches in accordance with the number and position of the tools, which are acted upon by the rod of an electromagnet which determines precisely the tool-changing rotation.

4. A revolving tool-carrier turret according claims 1 to3, characterized in that the wheel has at the rear a disc having detectors which determines in accordance with a proximity gauge the fixed angular positions corresponding 5 to the position of the different tools.

5. A revolving tool-carrier turret according to claims 1 to 4, characterized in that the shaft carries an intermediate pinion which can be coupled to the transmission of an auxiliary motor and has means for the coupling of a tool, such as a drill or the like, which is rotated by the motor when the shaft is in the unlocked position.

6. A revolving tool-carrier turret substantially as hereinbefore described with reference to the accompanying drawings.

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