WO1995032070A1

WO1995032070A1 - Turret lathe with two spindles

Info

Publication number: WO1995032070A1
Application number: PCT/SE1994/000469
Authority: WO
Inventors: Georg Furthmair
Original assignee: Evonova Ab
Priority date: 1994-05-20
Filing date: 1994-05-20
Publication date: 1995-11-30
Also published as: AU7133994A

Abstract

Multi purpose lathe including a main spindle (16) and a subspindle (19) and two tool revolvers or carriers (12, 23), one tool carrier (23) is arranged below the spindle axis and has its tool carrying end turned towards the subspindle (19). The other tool carrier (12) is arranged above the spindle axis and has its tool carrying end turned towards the main spindle (16). The lower tool carrier is supported on two lower guides (10, 11) and the upper tool carrier (12) is supported on two upper guides (7, 8) and the subspindle (19) is supported on an additional guide (9) between the two pairs of guides and the lowermost guide (11). On a slide (32) carrying the subspindle (19) this is arranged movable under the pressure from a hydraulic cylinder (30), that can press a center held in the subspindle (19) against an axle end when turning this.

Description

TURRET LATHE W I TH TWO SP I ND LES

This invention is related to a more versatile multioperational lathe than those on the market today. Today existing lathes are in principal specialised on different types of workpieces, which means that an engineering workshop with a diversified production needs a number of lathes of different types. One reason for the nonexistence of more versatile lathes is that these necessarely would be more expensive and more complicated. Also the general opinion is that versatility automatically leads to a loss of accuracy and a great escalation of costs. As a result no multi-purpose lathes exist on the market today.

Dependant on the desire to shorten storage and fabrication times, as well as a desire for adaptability to different products with an increasing variation between them the demands on the available machinery and its adaptability increase. Concurrent with the above demands one also continously wants to increase the accurracy and precision at the fabrication not least because in this way it is possible to reduce the number of machining steps for instance by eliminating subsequent grinding. In fabrication considerable time-savings can be achieved through a reduction of the number of resettings or remountings of the workpiece in a more versatile machine where the workpiece is transformed from raw material to a ready product by turning, drilling, cutting milling, threading etc., possibly first including a coarse machining and then a finer one to final measurements.

In other words there is today a need for a more versatile lathe than those existing today, that despite its versatility is to provide an accuracy equal to or even better than the lathes on the market today and with reasonable costs.

According to the invention the above object is achieved in a surprisingly simple manner with a lathe including two driven spindles and two tool carriers, the working areas of both extending over the entire working area of the machine between the spindles, the tool carriers being so arranged that they do not obstruct each others movements.

The tool carriers at known lathes obstruct each others movements and are not suitable to serve as a base for a lathe according to the above invention. It should be kept in mind that the tool carriers are comparatively bulky, since they contain slides, feeding means, drive means to rotate the tools, means for tool changing and tool magazines or revolvers. It is therefore the object of a further development of the invention to provide a lathe that can serve as a base for such a machine at which the tool carriers can move freely without obstructing each other all the way between the spindles.

With this object in mind in a further development of the invention the tool carriers are arranged diametrically opposite each other on two sides of the spindle axis and also turned opposed to each other. Due to this "Mirrorlike " appearance one tool carrier is with its tool carrying end (disc at a revolver lathe ) turned towards the subspindle while the other tool carrier is turned towards the main spindle. Preferably the tool carriers are arranged diametrically opposite each other relative the spindle axis preferably located in a vertical plane including the spindle axis one above and one below the spindle axis. In a further developement of the invention the tool carriers are each guided along two guides whereas the subspindle may be guided on one of the distal guides and a guide arranged between the pairs of guides for the tool carriers. In this way the guides for the subspindle will be far apart providing a steady mounting of the spindle but without hindering the movement of both tool carriers between the chucks. In this way a concept for an extremly versatile lathe is economically obtained that from a basic lathe with two tool carriers by simple exchange of the tool carriers can be updated from a revolver lathe to a machine that can carry out practically all machining that needs to be done to a workpiece.

Further advantages and features of the invention are apparent from the following description of two embodiments shown in the drawings. In the drawings fig 1 shows a revolver lathe according to the invention seen from the front, fig 2 the same lathe seen from the side and fig 3 a variety of the lathe shown in fig 1 and 2 in a view corresponding to fig 2.

The lathe shown in fig 1 and 2 is arranged on a base frame 1 that in turn rests on the ground in only three support points, adjustable to their height. At each of these a bowl is placed on the ground with a conical hole in which a steel ball lies and against which a bolt 4 with a likewise conical recess in the end is adjustable in a threaded hole in a bracket 5 on the support 1. In this way the lathe will be uneffected by the supporting ground, the tensions in the lathe due to the supporting forces against the ground will always be the same. The base frame 1 is a welded box construction filled with polymer concrete.

On the support 1 rests a lathe bed 6 the crossection of which has the shape of an 8 or two squares, one above the other. The lathe bed 6 is provided with five guides which from top to bottom have been denoted 7 to 11. On the uppermost guides 7 and 8 an upper tool revolver 12 is supported with a vertical slide, tool disc, position drives for these and tool magazine etc. For the lengthwise positioning of the tool carrier a measuring scale serves and for a translational movement paralell to the spindle axis an servo feed motor 14 with screw 15 serves, the motor being located in a recess outside of the part of the bed that is shaped as an 8.

The upper tool revolver 12 has its tool carrying end (disc) turned to the left in fig 1, that is towards the main spindle 16 of the lathe. The tools are mounted radially on the revolver disc.

A subspindle 19 is arranged in line with the main spindle 16 and provided with a belt drive 21 and an motor 20. The subspindle 19 is supported and guided by the middle guide

9 and the lowermost guide 11. For the longitudinal or axial movement of the subspindle 19 a screw 35 and motor (not shown) are arranged. The positioning of the subspindle is made with the help of a measuring scale 31 and a measuring head on the subspindle casing.

Below the spindle center an additional tool revolver 23 is arranged on the lathe with the tool carrying end towards the subspindle. The lower tool revolver is as is in particular appearant from fig 2 supported and guided by the two lowermost guides 10 and 11, and movable along these by a screw 24, the positioning or measuring thereof being carried out on the same measuring scale 31 that is used by the subspindle and an additional measurement head mounted on the tool revolver frame.

In fig 1 the tool revolvers 12 and 23 are shown in their opposite end positions. In phantom lines the opposite end positions are also shown. The tool carriers are thus movable over the entire working area between the chucks 27, 28 of the spindles 16 and 19. A major part of the lower tool carrier passes the main spindle 16 below this and behind it wheras the upper tool carrier passes above and behind the subspindle. Behind the spindles the tool carriers do not extend into each others areas of movement and they can consequently move freely independent of each other.

In order to provide the computor of the lathe according to the invention with information the mentioned measuring scales are used cooperating with reading means on tool carriers and subspindle slide, to indicate the longitudinal positions of these. In a similiar way the tool carriers include means indicating for instance the vertical positions of the tools. Main and subspindles are also provided with means measuring the angular position of spindles. In this way it is possible to run the two spindles absolutely coinciding, with identical speeds and angular positions, which in turn means that a workpiece even when rotating very fast can be transferred from the chuck of one spindle to the other.

The lower tool carrier can also position suitable supports for a long workpiece by fetching and releasing these at intended locations. The subspindle and the tool carriers are further provided with hydraulic locking means capable of holding them securely in their intended positions .

As is shown in fig 2 the subspindle is supported on the guides 9 and 11 via a slide 32 on which the subspindle frame via roller guides 33 and 34 is arranged movable in the lengthwise direction of the spindle. The movement enabled in this way is however comparatively short (ca 50 mm) and limited by end-stops. The movement is controlled by an hydraulic piston 30. In this way it is possible hydrauliccally to press a center in the subpindle against an axle that is to be turned.

At the turning of axles or shafts the shaft is held in the main spindle, the subspindle is brought to a position with a center carried by this a few millimeters from the shaft, the intermediate slide is locked hydraulicly and then the piston 30 is actuated pressing the center held in the subspindle against the workpiece or shaft. When the turning is over the hydraulic piston is withdrawn back to a defined end position in contact with an end-stop on the slide 32. In the embodiment of the invention shown in fig 3 the lathe bed 41 is lower and the guides of the upper tool carrier are arranged on top of the bed. The upper tool carrier also includes an intermediate slide 43 allowing horisontal lateral movement (y-axis) in order to improve the ability of the lathe to machine different types of workpieces. The lathe in this version is provided with a machining head 42 with greater output than that of a normal tool carrier so that proper and fast machining operations can be carried out by the lathe and not only turning operations. One of the spindles, preferably the main spindle can in this typ of operation hold the workpiece in defined locked positions or with a controlled turning during a cutting process. The subspindle and the lower tool carrier are arranged in the same way as in the embodiment shown in fig 1 and 2. In a further development of the embodiment shown in fig 3 the machining head may also be pivotable around a for instance vertical axis (b-axis).

Within the concept of the invention it is also possible to arrange the subspindle movable vertically, enabling the milling of threads on the inside or outside of a workpiece held by the main spindle while a cutting tool is held by the subspindle. With the lathe according to the invention machining and turning can be carried out on the front as well as the back side of a workpiece mounted in any of the spindles or in both in six axis or more. Furthermore the tools of both tool carriers can work over the entire length of one workpiece or of two workpieces. Simultanously two workpieces can be worked on and they can be transferred from one spindel to the other and back again while rotating at full speed so that in many appliancies or types of workpieces the lathe can work constantly without interruptions or timeconsuming resettings.

To achieve a minimum of standstill if a spindle becomes too worn it is suggested that the spindles are journalled in a sleeve each that by means of radial flanges are bolted to the spindle frames. In this way the bearing unit can be exchanged quickly and the lathe be used again, while the worn bearing is repaired.

Also so called long-hole-drilling can be performed with the invented lathe. The lathe according to the invention is from its simplest basic version without expensive and complicated rebuilds successively completable with additional machining possibilities from working in four axis and upwards with more and more axis. This in particular is the case with the embodiment of fig 3 with an angled bed.

The lathe according to the invention enables the working of front and back sides of workpieces in both spindles at the same time and independently if so should be desired. Furthermore axle turning can be carried out over the entire working length of the lathe.

With the tool carrying end of the lower tool carrier turned towards the subspindle a workpiece in the subspindle can be machined or cut also the distal end or backside by a tool in this lower tool carrier. Despite this the lower tool carrier can be supported on at least partly the same guides as the subspindle. The reason for this is the lower tool carrier does not have to pass the subspindle. Likewise the upper tool carrier dose not have to pass the main spindle. These guides can however be comparatively short the lower most only lengthened with the length of the tool carrier, this keeps fabrication costs down. Despite the fact that the lathe according to the invention almost can work as two independent lathes the fabrication cost of it is reduced by the features of the invention. By arranging the other tool carrier turned the other way there will be space enough beside the subspindle as well as beside the main spindle to allow good space and access to these and their parts as well as allowing a very stable and unyielding structure, which is necessary in order to obtain good precision. Still the lathe is short in relation to its working length despite the fact that the guides for subspindle and tool carrier partly are the same. Since the length of the bed and the guides greatly influences the cost when fabricating the lathe this effectively helps in holding the costs down.

Claims

C L A I M S

1. Lathe, characterized in that it comprises two rotatable spindles and two tool carriers, that both can move over the entire working area of the lathe between the spindles independently of each other and without obstructing each others movements, enabling axle turning over the entire working length and working on the front and back side of a workpiece at both spindles and independently.

2. Lathe according to claim 1, characterized in that the tool carriers are oriented opposed to each other.

3. Lathe according to claim 1 or 2, characterized in that it has a vertical bed with the guides arranged essentially vertically over each other.

4. Lathe according to claim 1 or 2 characterized in that the bed is angled with lower guides arranged over each other and upper guides in an essentially horisontal plane.

5. Lathe according to any of the previous claims, characterized in that it is provided with five guides.

6. Lathe according to any of the previous claims characterized in that on the two upper guides is supported a tool carrier , on the two lowermost guides a second tool carrier and on the middle guide and the lowermost guide is the subspindle supported.

7. Lathe according to claim 1 characterized in that the tool carriers are arranged diametrically opposite each other relative the spindle axis.

8. Lathe according to any of the previous claims, characterized in that the subspindle is provided with an additional slide allowing limited movement in the axis direction of the spindle and that a pressure cylinder is arranged to press the subspindle with this slide towards a workpiece mounted in the main spindle.

9. Lathe according to any of the previous claims characterized in tiiat the subspindle and the lower tool carrier use the same meassuring scale for positioning.

10. Lathe according to any of the previous claims characterized in that the bed or its support is supported on the ground in three points, preferably via intermediate balls.

11. Lathe according to any of the previous claims characterized in that the lower tool carrier has its tool carrying end turned towards the subspindle.