GB2176721A - Machine tool apparatus - Google Patents

Abstract

A machine tool apparatus comprises a separate work carrying unit 1 and tool carrying unit 2. The units can be adapted with various work and tool holding accessories or be combined with other units to carry out a range of operations including turning, milling, grinding and welding. <IMAGE>

Description

SPECIFICATION Machine Tool Apparatus This invention relates to machine tool apparatus.

The use of increasingly sophisticated computer control techniques has allowed the manufacture of more complex machine tools capable of machining to greater degrees of accuracy. However, such machines are generally expensive and require the workpiece to be precisely mounted to ensure accuracy.

According to the present invention there is provided machine tool apparatus comprising a workpiece carrying unit and a tool carrying unit, the workpiece carrying unit being separate from the tool carrying unit, wherein there is provided means for determining the relative positions of a workpiece carried by the workpiece carrying unit and a tool carried by the tool carrying unit and means for effecting relative movement of said workpiece and said tool.

Preferably, the workpiece carrying unit is a movable head member.

Preferably also, the tool carrying unit is a fixed tool member.

A rotatable chuck member may also be provided on the workpiece carrying unit for turning operations.

Suitable tool members may be provided for various different tasks, for example, turning, milling, grinding and welding.

Further the apparatus is provided with a tool magazine for storing alternative tool members.

Preferably, the apparatus has alternative mounting positions for tool members to allow a second tool to be mounted on the apparatus while a first tool carries out a machining operation.

Clamp units may be provided for mounting workpieces in position.

Tool members in the form of boxtooling may be provided, said tool members being arranged to pass over a workpiece to allow the full length of the workpiece to be machined.

The boxtooling may have a vibration unit included.

Several head members and tool members arranged in a spoke layout may be provided with a circular overhead rail structure with one or two robots arranged on a cross rail. A mixture of milling and turning operations can thus be quickly carried out on a workpiece. Gantry robots mounted on a cross rail can be used to service a machine layout.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:~ Fig. 1 is a schematic plan view of head and tool bed units of machine tool apparatus made in accordance with the present invention; Fig. 2 is a schematic side view of the apparatus of Fig. 1; Fig. 3 is a schematic plan view of a chuck and drive unit of apparatus of the present invention; Fig. 4 is a schematic side view of a milling operation on apparatus of the present invention; Fig. 5 is a schematic side view of a milling cutter of the apparatus of the present invention; Fig. 6 is a side view of a tool magazine of the apparatus of the present invention; Fig. 7a is a sectional side view of a clamp unit of the apparatus of the present invention; Fig. 7b is a plan view of a pallet top of the present invention;; Fig. 8a is a plan view of a boxtooling unit of the apparatus of the present invention; Fig. 8b is a sectional side view of the box-tooling unit of Fig. 8a taken along line A-A; Fig. 9a is a plan view ofa vibration unit for the boxtooling unit of Fig. 8a; and Fig. 9b is a side view of the vibration unit of Fig.

9a.

Referring to the drawings, one embodiment of machine tool apparatus according to the present invention comprises a head member 1 and a toolbed in the form of a tool mounting member 2.

The head member 1 is capable of slide displacement in the X and Z axes for turning and the X, Y and Z axes together with rotary table movement for milling. The head member 1 is a free standing unit which carries a drive unit of a spindle housing motor and chuck for turning or an alternative centre section to obtain Y axis movement and with a drive unit for a rotary table for milling. The tool mounting member 2 carries either tools suitable for turning operations or milling cutters 3 driven by drive motors 4 (Fig. 5). As the appropriate cutting tool is fixed in position on the tool mounting member 2 there is no need for any solid contact between the head member 1 and the tool mounting member 2 once the units have been initially aligned.The workpiece 5 is first positioned approximately on the head member 1 (see Fig. 4) and the sensors on the head member 1 then determine the position of the workpiece 5. The position of the workpiece 5 is then altered to bring the workpiece into correct alignment by movement of the head member 1 in the form of rotation at point C and tipping at point B (see Fig. 4). Any rotation required during the machining operation is accomplished at the normal rotation plane A.

The alignment of the head member 1 allows positioning errors to be corrected by the machine itself including those errors arising inherently in the apparatus itself.

An advantage of the head member 1 and tool mounting member 2 not being interconnected is that vibration is not transmitted from one to the other thus eliminating a common source of tool failure.

In use for milling, the machine tool apparatus provides for all axis movement by way of the movement of the head member 1. That is X, Y and Z axis movement plus rotation by rotary table together with the additional rotary movement and tipping movement already described for initial workpiece location. The tipping movement also allows the workpiece to be tipped through 90 degrees for working of appropriate.

All the movements necessary to carry out the milling operation are generated by the head member 1 itself whilst the cutting tool remains fixed on the tool mounting member 2.

This means that point to point or continuous path machining is possible under computer control on any axis or combination of axes, including compound angle milling operation.

Turning operations are carried out in a similar manner. The head member 1 has a chuck and drive unit 6 and carries out all movements including part rotation and the cutting tools are mounted in a firm position on either side of the tool mounting member 2. Multitool turrets are usable and heavy roughing cuts can be carried out by means of open roller box tools able to pass completely over the work up to the chuck face with preset cuts appropriate to the material on axis Z-1 (see Fig. 3) and finishing cuts taken from a tool on the tool turret on the Z-2 axis.

Taper cutting, contouring and thread chasing are all possible under computer control with continuous path capability.

The rough cut tool turret on the tool mounting member 2 contains a firmly fixed base unit with a revolving turret having 4~6 holes for roller box bushings able to pass over a shaft up to the chuck face. Toolbits, bushing assemblies and rotating turret bodies can be changed.

The finished turn tool turret, which can also be used for grooving and internal drilling can have, for example, 12 positions.

The provision of drive unit travel allows thread chasing by spindle movement and, if desired, taper turning by allowing for some radial movement in the head member 1.

For milling, the tooling is in the form of removable quill type tools inserted into fixed drive motor units, which can be of variable speed and with a reversing facility, mounted at the turret location.

The two basic pieces of apparatus, the head member 1 and the tool mounting member 2 can, with the addition of suitable attachments, carry out most machining operations.

In addition to milling and turning, suitable attachments can be provided for spinning, grinding and welding. Spot welding or seam welding in 3 dimensional axes can be accomplished by a fixed welding unit on the tool mounting member and movement of the head member 1 presents the part to the welding unit in an appropriate position.

Large parts can be mounted on the tool mounting member and the head member 1 can then function as a boring mill. Point'O' (see Fig. 2) provides location for a centre support in shaft machining if necessary.

Fig. 6 illustrates a multitool magazine 10. The tools 11 are carried, cutting edge inwards, in the magazine 10. The magazine 10 is in the form of a drum 12 which can, under computer control, be rotated, raised or lowered and moved forwards and backwards to load a tool 11 onto a base member 13.

The base member 13 has a rotatable tool mounting member 14 which allows one tool to be loaded onto the base member while a previously loaded tool is in operation.

Fig. 7 illustrates a clamp unit 15 which can be used for holding parts in place on a pallet 16 to allow machining to be carried out.

The clamp pressure can be easily adjusted to allow for fragile part holding and to allow a quick non-slip fastening.

Figs. 8a, 8b, 9a and 9b illustrate box tooling 17 for roughing cuts. The tools are of predetermined size, have renewable inserts and a vibration unit 18 for chipbreaking if required.

The tool mounting member 2 in addition to tool carrying can be arranged to accommodate a coolant tank and to incorporate swarf disposal facilities.

A system using machine tool apparatus of the present invention has a number of advantages.

By substituting head and tool members it is possible to carry out a number of different machining operations using the basic head and tool holder units.

Various units can be easily interchanged and the system can be extended merely by adding additional units when required.

Standard computer programmes can be produced to carry out the various machining operations or alternatively programmes may be produced to match the specific needs of a particular machine user.

Modifications and improvements may be made without departing from the scope of the invention.

Claims (4)

1. A self-contained machining unit able to carry out turning and milling type operations alone or linked to other similar machines.

2. A machining unit not limited to turning and milling type operations.

3. A machining unit able to be used by mounting tooling on moving unit in continuous machining to other components arranged around it in sequence.

4. A machining unit substantially as described having reference to sheets 1/4, 2/4, 314 and 4/4 in accompanying drawings.