Tool and method for machining workpieces

BACKGROUND OF THE INVENTION

The invention relates to a tool for both machining and deburring workpieces and to a method of machining and deburring workpieces.

Tools and methods of the type addressed here are known. In particular in machining installations, tools of various types are used to machine workpieces. It has been found that burrs develop in the process, and these burrs may lead to a permanent risk of injury. Therefore, deburring tools are used after machining of workpieces to remove the burrs and the risk of injury as far as possible. A second tool is required to remove the burrs produced during the machining. This requires a tool change in many cases. In machining installations, however, this is also a great disadvantage, since considerable space is required due to the various tools. Also, in general, providing such tools is very disadvantageous with regard to the parts held in stock.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to provide a tool for machining workpieces that does not have the disadvantages noted above.

To achieve this object, a tool of the invention has both elements for machining a workpiece and then deburring it. It is distinguished by comprising a deburring device, which enables removing the burrs produced during the machining, without requiring the use of a separate tool.

In one embodiment of the tool, the deburring device interacts with an actuating device which ensures relative movement between a deburring tool and a cutting edge of the tool. It is possible to retract and extend the deburring tool so that, after machining a workpiece with the deburring tool retracted, the burr that was produced is removed by the deburring tool, which is then extended.

To achieve the object, a method of machining workpieces is also proposed, in which both the machining and the deburring of the workpiece are performed by the same tool.

Other objects and features of the invention are explained below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a diagrammatic view of a tool in plan view, namely of its end face;

FIG. 2

is a view of the tool in

FIG. 1

, in partial section;

FIG. 3

is a detail of the tool, particularly a deburring device, in a first functional position,

FIG. 4

is a view like

FIG. 3

showing the deburring device in a second functional position, and

FIG. 4A

is a view as in

FIG. 4

showing an electromechanical actuation.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1

shows a tool

1

according to the invention including a main body

3

having circumferential peripheral surface

5

. At least one cutting edge

7

projects outward beyond the surface.

FIG. 1

shows two cutting edges

7

and

7

′ in this simplified diagrammatic drawing. There may be up to twelve cutting edges projecting beyond the surface

5

of the tool

1

. The cutting edges

7

are part of a cutter tip

9

which is fastened to the main body

3

conventionally, for example, by a clamping jaw (not shown here) and a “cassette”, which is preferably adjustable relative to the main body

3

such that the machining radius can be set precisely.

During machining of a workpiece, the tool

1

is normally rotated counterclockwise in

FIG. 1

, so that the cutting edges

7

of the cutter tips

9

can remove chips from the workpiece.

Viewed in the rotation direction of the tool

1

indicated by an arrow

11

, a respective chip space

13

,

13

′ for disposal of chips is located in front of, i.e. it leads each cutting edge

7

, that is, in front of a cutter tip

9

. Chips removed by the cutting edges

7

,

7

′ therefore pass into the respective chip spaces

13

,

13

′ and may be disposed of from the spaces.

The construction and functioning of a cutting tool are known in principle. It is essential that during rotation of the tool, chips are removed by the cutting edges from the workpiece to be machined. Machining generally produces burrs.

The tool

1

has a deburring device

15

which comprises at least one deburring tool

17

associated with one or more of the cutting edges

7

.

FIG. 1

shows a deburring tool

17

′ associated with the cutting edge

7

′. Ten further deburring tools are provided here. Each tool is indicated by concentric circles K

1

, K

2

at the periphery, as described below. A cutting edge or a cutter tip is associated with each deburring tool, and vice versa, providing as many cutting edges or cutter tips as deburring tools. Instead of providing individual deburring tools assigned to the individual cutting edges, a single, possibly also larger, deburring tool may be assigned to a plurality of cutting edges. However, the number of cutting edges or cutter tips and deburring tools is not critical for the functioning of the tool

1

.

The tool shown in

FIG. 1

is shown in side view in

FIG. 2

, parts of the tool

1

being sectioned.

FIG. 2

shows a plurality of the cutter tips

9

, each projecting beyond the peripheral surface

5

of the body

3

of the tool

1

and having cutting edges

7

which also project forward beyond the end face

19

of the tool

1

. For example, the tool

1

shown is a face milling cutter.

FIG. 2

shows cassettes

21

, which are fastened to the main body

3

of the tool

1

. The cutter tips

9

are clamped in position on the cassettes in a conventional manner. Each cassette is adjustable in the direction of the center axis

23

of the tool

1

by a known type of adjusting device

25

schematically indicated. The devices

25

serve to displace the cutter tips

9

to a greater or lesser extent beyond the end face

19

of the tool

1

. Corresponding adjustability in the radial direction, perpendicular to the center axis, may also be provided.

Recesses

27

in the body

3

of the tool

1

running parallel to the center axis

23

accommodate respective deburring tools

17

, as explained with reference to

FIGS. 3 and 4

.

On its axial side opposite the end face

19

, the main body

3

has a flange

29

secured to it which comprises branch passages

31

that extend in the direction of the center axis

23

and are connected to one another, for example, by one or more annular passages

33

. These form a media connection with the recesses

27

.

The tool

1

may be connected with the flange

29

and a known fastening shank

35

to a machine tool or a machining installation, not shown. The partial sectional view of

FIG. 2

shows that the fastening shank is hollow with an interior space

37

which provides a media connection to the annular passage

33

, and thus to the branch passages

31

and the recesses

27

, and a coolant/lubricant can be fed to the cutting edges.

As supplying tools with coolant and/or lubricant or other media via a shank is known in principle, this is not dealt with in more detail.

FIG. 3

shows a deburring tool

17

of the tool

1

in section and on a greatly enlarged scale. A recess

27

in the main body

3

comprises a stepped bore that accommodates the deburring tool

17

. The tool

17

comprises a wire brush

37

, and a fastening device

39

. The brush preferably has an abrasion resistant coating thereon. The device

39

comprises an actuating piston

41

disposed in a sealing manner in the top region

43

of the recess

27

which can be displaced along the direction of the longitudinal axis

45

of the recess

27

. The actuating piston

41

has an underside which faces the axial end face

19

of the tool

1

. An actuating pin

47

attached to the underside of the piston

41

has a wire brush

37

fastened to it, for example, screwed on by a threaded stud

49

. The outside diameter of the actuating pin

47

is smaller than the inside diameter of the recess

27

, leaving space for an elastic element, here a helical spring

51

, around the actuating pin. The helical spring

51

is supported between a bottom step of the recess

27

and on the underside of the actuating piston

41

and is preloaded in the recess

27

. The helical spring

51

therefore presses the actuating piston

41

upward. The piston

41

is supported on a suitable abutment, here a closure plate

55

. The plate is attached in the body

3

of the tool

1

and is fixed there by means of fastening screws

57

.

FIG. 3

shows the actuating piston

41

located in its top first functional position, on the stop at the closure plate

55

, where the deburring device

15

or the deburring tool

17

is inactivated, with the wire brush

37

is pulled filly into the bottom part

59

of the recess

27

and not projecting beyond the end face

19

of the tool

1

.

The orifice region of the bottom part

59

in the end face

19

has a conically widened portion

61

, which is schematically indicated in

FIG. 1

by the concentric circles K

1

and K

2

.

When the actuating piston

41

is displaced from its position shown in FIG.

3

and against the force of the helical spring

51

downward into its second functional position, it eventually strikes a top step

63

of the recess

27

, for example a stop ring

65

, which is inserted into the recess

27

and is arranged concentrically to the longitudinal axis

45

.

A connection piece

67

is attached to the closure plate

55

. This connects the recess

27

to a media supply via a connection hose

69

. It is possible to build up positive pressure on the top side of the actuating piston

41

, remote from the end face

19

, for example by compressed air or a hydraulic fluid. This builds up a downwardly directed force which is eventually larger than the counterforce of the helical spring

51

. This displaces the actuating piston

41

, and the actuating pin

47

and the deburring tool

17

, that is the wire brush

37

, downward.

FIG. 4

shows the actuating piston

41

displaced downward and the deburring tool

17

or the wire brush

37

extended beyond the end face

19

. The widened portion

61

enables the wire brush

37

to fan out, as shown in FIG.

4

.

FIG. 4

shows an embodiment which is slightly modified compared with

FIG. 3

, wherein the closure plate

55

is slightly smaller. However, the basic structures of the deburring tool

17

and of the actuating device

39

are identical.

In

FIG. 4

, the top step

63

and the stop ring

65

are not present. Downward movement of the actuating piston

41

is limited by the helical spring

51

being fully compressed, wherein all of the spring coils bear against one another and further compression is not possible.

In this actuating device

39

in

FIG. 4

, downwardly directed movement of the actuating piston

41

, the actuating pin

57

and the deburring tool

17

or the wire brush

37

requires that the actuating piston

41

be acted upon on its top side by a pressure P which is greater than the counterforce of the helical spring

51

. This extends the deburring tool

17

beyond the end face

19

of the tool

1

making it available for deburring.

To build up the pressure P, it is not critical whether a pressurized medium is admitted to the recess

27

above the actuating piston

41

via a connection piece

67

, as shown in

FIGS. 3 and 4

, or via a flange

29

, shown in FIG.

2

. This is because, if a pressurized medium is admitted to the annular passage

33

, pressure is likewise built up in the branch passages

31

. This pressure is then transmitted to the top side of the actuating piston

41

remote from the end face

19

, so that the actuating piston

41

is finally displaced against the force of the helical spring

51

, causing the deburring tool

17

to extend from the body

3

of the tool

1

.

The actuating device

39

has pressure applied to the actuating piston

41

, whether by means of a gaseous or liquid medium, to activate the deburring device

15

and push out the deburring tool

17

, that is the wire brush

37

, beyond the end face

19

of the tool

1

against the force of a restoring device, which comprises the helical spring

51

for example.

When the pressure on the top side of the actuating piston

41

is reduced, the helical spring

51

pushes the actuating piston and the deburring tool

17

back into the initial position and the wire brush

37

is displaced back into the body

3

of the tool

1

.

The functioning of the tool and the method of machining workpieces is now described.

In a first machining step, the tool

1

removes chips from a workpiece. In the process, it is ultimately not important whether the tool

1

is a milling cutter, as in

FIGS. 1 and 2

, or another type of tool used for machining, for example a reamer. During the machining, the cutting edges

7

project beyond the circumferential surface

5

and if necessary, beyond the end face

19

of the body

3

of the tool

1

and can remove chips from the workpiece. During this operation mode of the tool

1

, the deburring device

15

is inactivated, with the deburring tool

17

or the wire brush

37

pulled into the body

3

. After machining, the tool

1

is lifted from the workpiece to be machined and moved back into its initial position. The deburring device

15

is now activated, with the deburring tool

17

, here a wire brush

37

, is extended from the body

3

such that the top surface of the workpiece can be processed with the deburring tool

17

in a further step of the method.

The following aspects are crucial. In a first step of the method, the workpiece is machined by the tool

1

. In a second processing step, the workpiece is deburred directly with one and the same tool. To this end, relative movement is required between the cutting edges

7

and the deburring tools

17

. In this example, the actuating device

39

prevents the wire brushes

37

or deburring tools

17

, which are retracted, from contacting the surface of the workpiece but that instead the cutting edges

7

first remove chips. Then the deburring tools are extended for deburring the workpiece surface.

Movement of the cutting edges

7

is conceivable. The cutting edges

7

could first be extended far enough so that, during rotation of the tool

1

, the edges extend further beyond the outer contour of the tool than the deburring tools or wire brushes. A workpiece may be machined in this functional position. After the machining, the cutting edges can be pulled in, so that the deburring tools may process the workpiece surface. Even if this functional mode were possible, the functional mode described first is preferred, since the cutting edges then do not need to be moved for the change of function of the tool

1

and can therefore be initially positioned very precisely in the main body

3

. During retraction and extension of the deburring tools, particularly if they are designed as wire brushes, the distance to which the brushes are extended is not crucial. It is only crucial that the brushes project outward beyond the main body

3

further than the cutting edges

7

in order to carry out the deburring.

During the deburring of workpieces, wire brushes

37

with individual bristles that have an abrasion-resistant coating are used to provide a long life of the tool

1

.

In addition, actuating devices

39

of different design activate and drive the deburring tools, namely such which retract and extend the deburring tools

17

electromechanically, may also be used as shown in FIG.

4

A. In this figure. a magnetic element

75

and a solenoid

76

are provided in place of the actuating piston

41

. The actuation of the solenoid moves the magnetic element to retract and extend the deburring tools. Finally, the actuating device

39

may be actuated as a function of rotational speed, for example by known bodies which, starting from a certain rotational speed, are displaced against the force of a spring and can thus be used for actuating the deburring tools

17

. In this case, too, reversal of function is ultimately possible, that is displacement of the cutting edges relative to fixed wire brushes. Apart from that, in all cases, a combination of the various activation types (pneumatic, hydraulic, mechanical by centrifugal force, mechanical by means of an electromagnet) is possible to produce relative movement between cutting edges and deburring tool.

The tool

1

preferably has cutter tips

9

, although displacement of the cutter tips is possible for exact adjustment of the tool

1

. The deburring tools

17

, that is the wire brushes

37

, are displaceable by an actuating device

39

, so that both machining and deburring of workpieces is possible using the tool

1

. The tools required for machining workpieces, and also the space requirement of corresponding tool centers or machining installations, may be substantially reduced. In this case, the tool

1

is of simple construction and is less susceptible to trouble or wear.

Further, machining and deburring can be performed in the same operating cycle. This is achieved by the deburring tools already being activated, that is extended, during the machining.

This is a very time saving method of machining. However, the advantage of the method described above is that the two sequences of operations, machining and deburring, do not have an adverse effect on one another.

Although the present invention has been described in relation to a particular embodiment thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited to not by the specific disclosure herein, but only by the appended claims.