GB2169528A - Turret indexing - Google Patents

Abstract

A tool turret has a housing (1) and a revolving tool head (5) which can be locked relative to the housing (1) by means of gear teeth including annular toothed rings (32, 37, 38) with axially extending teeth which can be interlocked in different rotational positions. A device having a cam drive controls the selective locking and unlocking of the teeth of the rings (32, 37, 38) the cam drive being arranged coaxial with a shaft (20), and acted upon by a spring (14) which tends to maintain the teeth on engagement. The cam drive has an annular groove (having walls 33,34) in which rides a cam follower (35) which is mounted on an axially movable, annular locking element (36) which carries one set of teeth on a ring (37). The set of teeth can be removed axially to concurrently engage rings of teeth on the head (5) and the fixed housing (1) locking the head (5). <IMAGE>

Description

SPECIFICATION Tool turret This invention relates to a tool turret of the type which is rotatable to a plurality of angular positons, the turret including a rotatable head, a housing and drive means for rotating the head to any of the positions.

In a known tool turret of the type which the invention relates, an example of which is shown in German Patent 16 27 051, a cam drive is provided for disengaging facing gear teeth, and another cam drive is provided for engaging the facing teeth. In this apparatus, the rotating head must be lifted out during the disengagement of the teeth and reinserted for re-engagement thereof, so that the teeth will mesh again. The cam drive for disengaging the teeth includes an axial cam which works on the rotating head through a lug and a multiple-disc brake which creates the danger of force being applied excessively to one side. The cam drive for engaging of the teeth includes a radial cam which acts on gear teeth through a toggle lever mounted on the rotating head. This apparatus for selectively engaging and disengaging the facing teeth is very costly and occupies a considerable amount of space.

In another known tool turret shown in German Auslegeschrift 28 49 167, the cam drive has a member'with an annular groove into which fits a guide member which is attached to a lever. A control element which rotatably supports the member with the annular groove in it is mounted on an axis parallel with the axis of the rotating head.

The axis of the rotating head passes through the annular lever which acts on its shaft by means of a toggle lever coupling against the force of a spring when the gear teeth arrangement is to be engaged.

This emmodiment of the tool turret requires two shafts arranged side-by-side and, therefore, also uses much space and is expensive.

A multiple tool holder for machine tools has an annular locking part is also known, an embodiment of this being shown in German Offenlegungsschrift 2741 907 and U.S. 2,202,227. This locking apparatus has a locking part with teeth on a facing side and axial cams on its other facing side by which the locking part can be axially forced against the bias of a spring. The other teeth of the facing teeth cooperating with those mounted on the locking part, and belonging to the facing gear teeth, are mounted on the rotating head and on a stationary part coaxial therewith. The facing cams on the locking part and on the stationary part of the multiple tool holder are permanently under spring bias, which creates increased frictional resistance.

An object of the present invention is to construct a rotatable tool turret which is simple in construction and operation and which occupies minimum space.

According to one aspect of the present invention, a tool turret comprises a housing, a rotatable turret head and an annular locking part arranged coaxially with the latter and carrying axial teeth for cooperation with axial teeth on the housing and on the turret head, the locking part being the driven part of a cam drive arrangement whereby the locking part is axially movable, the driving part of the cam drive being swingable around the axis of rotation of the turret head, the cam drive including a closed control slot bounded by two side walls and a guide member engaging in the control slot.

According to another aspect of the invention, a tool turret comprises a housing, a rotatable turret head, an annular locking part coaxial with the turret head and having axial teeth cooperable with axial teeth on the housing and on the turret head, a portion of a cam drive, by means of which the locking part is axially movable, and a spring which can be brought into action between the locking part and the turret head, the spring being arranged on that side of the axial teeth remote from the turret head and, at least in the position of engagement of the locking part, seeking to press said part in the direction of the axial teeth on the housing and on the turret head, the force of reaction of the spring acting on the turret head and seeking to press said turret head against the housing, and the cam drive being adapted and arranged to disengage the axial teeth on the locking part from the axial teeth on the turret head and on the housing.

The investment to construct a tool turret in accordance with the invention is very low. It facilitates rapid, exact adjustment, even with a large load. The arrangement of the annular groove coaxially with the axis of the rotating head, the use of annular locking part coaxial with the rotating head, which supports the teeth on one side of the facing gear teeth, and the teeth of the facing gear teeth found on the other side in two coaxial rings, of which one ring is connected with a rotatable head and the other is stationary and wherein the two rings are overlapped by the teeth on the locking part, make space-saving construction possible, particularly because of the omission of one shaft parallel to the axis rotating head. The guide member is fixed in the annular groove and therefore is properly guided.

Further preferred features of the apparatus allow the teeth of the sets of teeth lying opposite each other to mesh precisely with each other without excessive axial stress on the teeth.

An energy saving drive of the turret is attained by further features since the spring for pressing the teeth into engagement is only effective when the teeth are meshed together and there is no axial urging when the teeth are not meshed.

The invention will be described further by way of example, with reference to the accompanying drawings, wherein Fig. 1A is a side elevation, in section along line IA-lA of Fig. 2; Fig. 1 B is a plan view in section, along line IB-IB of Fig. 2, Fig. 1 B constituting a continuation of Fig.

1A viewed from a different angle, the parts common to both figures being shown in dotted lines; and Fig. 2 is a transverse sectional view along line Il-Il which extends through Fig. 1A and 1 B.

As shown particularly in Fig. 1A, the apparatus includes a hollow cylindrical control elementwhich is rotatably mounted on roller bearings 2 in a housing 1 which can form part of a machine tool on a frame, the machinetool not being illustrated. Control element3 serves as a support bearing for a coaxial stepped shaft4which carries a rotatable head 5 at one end, the left end in the figure. The rotatable head 5 is coupled to the end of shaft 4 with a replaceable spacing ring 6 in between, the components being held together by screws 7 extending through the head and ring and into the end face of a radially enlarged portion 8 of shaft 4.

An annularsupport ring 9 of an axial bearing rides against rollers 10 which abut against a surface of control element3 axiallyfacing and adjacentto ring 9. A Geneva wheel 11 surrounds shaft 4 and is held on the side of element 3 which faces awayfrom revolving head 5 by means of a nut 12 screwed onto a stepped, externally threaded portion of shaft 4 shown atthe right side of the drawing. All of elements 3,9, 11 and 12 are supported on that part of shaft4 which extends away from head 5. A radially extending threaded setscrew 13 serves to fix nut 12 in place. Two cup springs 14 are arranged between Geneva wheel 11 and support ring 9. A key insert 15 forms a nonrotating connection of support ring 9 and Geneva wheel 11 with shaft 4 in tongue and groove fashion.The right end of shaft 4 (Fig. 1 B) is rotatably mounted in a bearing 16which is attached to a housing cover 17 by means of screws 18. Housing cover 17 covers the right side of housing 1. A drive motor, notshown in attahcedto housing cover 17 and hasadriveshaftcoupledtoa drive pinion 19 which projects through an opening in housing cover 17.

A shaft 20 which carries two pinions 21 (Fig. 1A) and 22 (Fig. 1 B) axially spaced from each other, is rotatably mounted at one of its ends in housing cover 17 and atthe other end in housing 1. Pinion 21 meshes with radially protruding peripheral gear teeth on control element3 and pinion 22 meshes with similarteeth on a drive disc 24 carrying two driving pins 23. Shaft 20 is supported at one end by a roller bearing 25 in housing cover 17 and atthe other end by a needle roller bearing 26 in housing 1. Roller bearing 25 is between apinion27,meshingwith drive pinion 19, and pinion 22. Drive disc 24 is cantilever mounted in housing cover 17 by roller bearing 28.As best seen in Fig. 2 Geneva wheel 11 has radially extending grooves 30 between eight axially protruding segment cams 29 for meshing with driving pins 23 of drive disc 24 which cooperate, in a known manner, with the Geneva wheel 11.

Rotatable head 5 is surrounded by an annular housing 31 which is fixedly attached to housing 1.A toothed ring 32 is also attached to housing 1 in an annular recess in rotatable head 5 which opens toward control elem ent 3. The teeth on ring 32 constitutes an annular arrangement of axiallyfacing gearteeth extending in the general direction of element3. Control element3 has an annular groove on its outside peripherydefined by two facing walls 33 and 34, which groove forms a lifting cam operating in both axial directions. Rollers 35which are arranged opposite each otherfit between walls 33 and 34, each ofthe rollers being rotatably mounted on a locking element 36 which is axially movable.Locking element 36 is formed with a toothed ring 37 on its side adjacent to roller head 5, and the axially extending teeth of ring 37 lie opposite the teeth of ring 32 and also the teeth of a toothed ring 38 formed on revolving head 5. The teeth in the sets ofteeth on rings 32 and 38 lie in the same plane, and considered together, have approximatelythe same radial extent as the radial extent oftheteeth on ring 37. When locking element 36 is in its end position toward the left, as shown in the drawing, the radial gearteeth are fixed or locked to each other because the teeth of ring 37 simultaneously mesh with the teeth of both of rings 32 and 38. If the locking element 36 is in its other end position toward the right, then the sets ofteeth on rings 32,37 and 38 are disengaged from each other.Compression coil springs 39 are clamped in recesses on the peripheries between rings 32 and 36 where they are arranged with their axes parallel to that of rotating head 5.

When drive pinion 19 is driven, drive disc 24 and control element3 are rotated continuously. Geneva wheel 11, however, is driven only when the teeth of ring 37 on theone hand and rings32and38onthe other hand are not meshed together, and thus, the facing gearteeth are disengaged. Following turning of revolving head 5thorugh one step, the angular extent of which is determined by the number of grooves 30 in the Geneva wheel 11, (there being eight grooves in the embodiment shown) the teeth of the facing gears for rings37, 32 and 38 mesh together again. Walls 33 and 34 of the control groove on the periphery of control element 3 are configured correspondingly. After rotatable head 5 has reached its new position, the drive power is automatically disconnected until the next movement isto occur.

While one advantageous embodiment has been chosen to illustrate this invention, it will be understood by those skilled in the artthatvarious changes and modifications can be made therein without departing from the scope of the appended

Claims (6)

claims. CLAIMS

1. Atool turret comprising a housing, a rotatable turret head and an annular locking part arranged coaxial with the latter and carrying axial teeth for cooperation with axial teeth on the housing and on the turret head, the locking part being the driven part of a cam drive arrangement whereby the locking part is axially movable, the driving part of the cam drive being swingablearoundthe axis of rotation ofthe turret head, the cam drive including a closed control slot bounded bytwo side walls and a guide member engaging in the control slot.

2. Atool turret as claimed in claim 1, characterised in thatthe control slot is provided on the driving part and the guide member comprises a roller which fits intothecontrol slotandwhich is rotatablymounted on the driven locking part.

3. Atool turret as claimed in claim 1 or2, characterised in thatthe driving part comprising the control slot is arranged inside the locking part carrying the guide member.

4. Atool turret as claimed in any one ofthe preceding claims, characterised in that the control slot is designed in such a way that a spring, which seeks to press the cam drive in the direction of the teeth provided on the turret head, only comes into action when the teeth of the driven part engage in the other teeth.

5. A tool turret comprising a housing, a rotatable turret head, an annular locking part coaxial with the turret head and having axial teeth cooperable with axial teeth on the housing and on the turret head, a portion of a cam drive, by means of which the locking part is axially movable, and a spring which can be brought into action between the locking part and the turret head, the spring being arranged on that side of the axial teeth remote from the turret head and, at least in the position of engagement of the locking part, seeking to press said part in the direction of the axial teeth on the housing and on the turret head, the force of reaction of the spring acting on the turret head and seeking to press said turret head against the housing, and the cam drive being adapted and arranged to disengage the axial teeth on the locking part from the axial teeth on the turret head and on the housing.

6. A tool turret as claimed in claim 5, characterised in that the spring is arranged between the turret head and a supporting part fixedly connected to said turret head, and in that a part of the cam drive which is axially movable with respect to the locking part is disposed between the spring and the turret head.