GB2352207A

GB2352207A - A plane knife with a cutting edge formed on an arc-shaped recess

Info

Publication number: GB2352207A
Application number: GB9927577A
Authority: GB
Inventors: Adolf Zaiser
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1998-12-07
Filing date: 1999-11-22
Publication date: 2001-01-24
Anticipated expiration: 2019-11-22
Also published as: GB9927577D0; JP2000167803A; GB2352207B; DE19856278A1

Abstract

A plane knife 21 for planing machines 10, in particular hand-held planing machines for machining wood, which has a cutting edge 25 along at least one longitudinal side 23 of its basic body 24, where the cutting edge is formed on the ridge of an arc-shaped recess 27 of the basic body. The cutting edge may take the form of a concave cutting edge which is semicircular, or elliptical in shape. Preferably the plane knife is part of a planing machine having a plane knife carrying shaft 20. A round, rod-shaped setting body 50 may be provided, the curvature of which corresponds to the radius of the cutting edge of the plane knife, and which may lie in a longitudinal groove 40 of a wedge-shaped body 29 of the planing machine.

Description

2352207 Plane ktufe hand-held planin- machines- for machining wQod The

invention proceeds from a plane knife for planing machines, in particular hand-held planing machines for machining wood, according to the preamble of claim 1.

From DE 42 04 775 C2 and also DE 195 36 559 A I 'in connection with an electric planing machine, in particular a hand-held planing machine, a rectilinearly extending plane knife-is known, which is fastened in an exchangeable manner to the plane shaft of the planing machine. Said known plane knives at least along one longitudinal side of their basic body have a longitudinally continuous cutting edge and are therefore suitable for end facing workpiece surfaces which are to be machmied, wherein the machining width corresponds approximately to the length of the plane knife.

Planing machines are also already known, which enable chamfening of rectilinearly extending workplece edges. To said end, the front bottom surface of the planing machine has approximately halfway along its width a longitudinal groove, which is approximately V-shaped in cross section and opens in a downward direction, so that the planing machine may be placed with said longitudinal groove onto the workplece edge and guided along the latter, with the result that charnfering of rectilinearly extending workplece edges is easily possible.

The plane knife according to the invention having the characterizing features of claim I has the advantage that, when said plane knife is inserted into the plane shaft, without any need for further modifications a planing machine is usable for roundig rectiliear workpiece edges. The plane knife according to the invention is suitable for a multitude of roundmig tasks especially in the case of 2 wood machining for completion of interior work in a building. In a simple manner, such a plane knife may be used to round shelves, squared timber, boards or similar workpieces in the region of rectilinearly extending edges by cutting planing work.

Advantageous developments and improvements of the plane knife indicated in claim I are possible by virtue of the measures outlined in the further claims.

There follows a detailed description of embodiments of the invention which are illustrated in the drawings. The drawings show:

Figure I a diagrammatic perspective view of a hand-held planing machine with a laterally attachable, angle-adjustable guide stop-, Figure 2 a diagrammatic, part-sectional side view of the hand-held planing machine in Figure I Figure 3 a side view of a plane knife of the hand-held planing machine; Figure 4 a side view of part of a plane knife according to a modified embodiment.

The planing machine 10 illustrated in Figures I and 2 takes the form of an, in particular, electric hand-held planing machine comprising a machine housing 12 with motor housmig 14 and a handle 16, which camies an electrical switch 18. In the machine housing 12 a plane shaft 20 is supported so as to be rotatable about its axis 19 in the direction of the rotafion direction arrow I I and carries plane knives 21, of which only one plane knife 21 is indicated 'in Fig. 2.

As the plane shaft 20 rotates, the plane knives 21 describe a circle of action which projects beyond the sole, in the form of base plate 26, of the planing machine 10 so that the cutting edges of the plane knives 21 may engage and cut into a non illustrated workpiece extending flush with the sole 26. An opening 28 disposed 3 in the base plate 26 for passage of the plane knives 21 Is closable by means of an articulated guard hood, which is not shown in detail.

In the front region, the planing machine 10 has a wedge-shaped body 29, with which the planing machine 10 likewise rests on the non- illustrated workpiece. The wedge-shaped body 29 is displaceable in Figure 2 to the right or in the opposite direction by turning a handle 30 and determines the distance of the plane shaft 20 from the non-illustrated workpiece and hence the depth of cut. The further the wedge-shaped body 29 is displaced in forward direction, i.e. in Fig. 2 to the tight, the greater the depth of cut.

As may be seen from Figure 1, a rebate depth stop 31 is fastenable detachably to one side of the planing machine 10 and is adjustable. Screw fastenable to the opposite side of the planing machine 10 is a guide and stop device 32, which is detachably fixable by means of a base carrier 33 to the machine housing 12. The base carrier 33 has a guide 34 for a lateral stop 36, which is provided with a suitable rail 35 and is fixable in the respective adjusted position relative to the guide 34 with base carrier 33 by means of a clamping screw 37. A stop 38 is held at an adjustable angle on the lateral stop 36 by means of clamping screws 39, which stop 38 in Fig. I is adjusted so as to be aligned at 90' relative to the base plate 26 but may instead, where required, also be adjusted for example 'in such a way that between the base plate 26 and the stop face of the stop 38 there is an angle of e.g. 135', which corresponds to an angle of 45' between the base plate 26 and a flat surface of a non-illustrated workpiece.

It is evident from Figure I that the wedge-shaped body 29 approximately halfway along its width has, in its bottom surface used for support on a workplece, a longitudinal groove 40 which is substantially wedge- shaped and forms e.g. a 90' angle. The longitudinal groove 40 extends over the entire length of the wedge-shaped body 29 and enables charnfening of straight edges of workpleces, for which purpose the planing machine 10 is held in such a way that 4 there is an angle of substantially 45' between the surface of the workplece and the sole formed by the base plate 26 and the wedge-shaped body 29. Depending on circumstances, said inclination of the planing machine 10 may be reproducibly guaranteed by suitable adjustment of the guide and stop device 32, as has been explained above. For charnfening an edge, the planing machine 10 is then placed with the longitudinal groove 40 onto the workpiece edge and guided along the latter.

As plane knives 21 for said workpiece machining as well as for the surface machining of flat surfaces, elongate flat plane knives 21 aligned parallel to the axis 19 are provided which, for example, have cutting edges extending rectilinearly along both longitudinal sides so that, by releasing and turning the plane knife, the one or the other longitudinally extending cutting edge comes into action and so both cutting edges of the plane knife 21 are usable.

The at least one plane knife 21 of the plane shaft 20, which has is continuous cuttig edges in longitudinal direction, is exchangeable for a plane knife 22 of a special type, which is shown in Figure 3 and has on one longitudinal side 23 of its basic body 24 a cutting edge 25 In the form of a concave cutting edge. The cutting edge 25 is formed on the ri'm of an arc-shaped recess 27 of the basic body 24. Said concave cutting edge 25 is approxninately semicircular in shape. It may, for example, have an approximately elliptical shape.

Like the other plane knives 2 1, the plane knife 22 is also provided at the rear side of the basic body 24 remote from the breast side with a longitudinal groove 44, into which in the usual manner clamping means of the plane shaft 20 may engage positively for fixing the plane knife 22 on the plane shaft 20. The part 45 of the basic body 24 containing the cutting edge 25 and extending on the one side of the longitudinal groove 44 is wider than the other part 46 extending on the other side of the longitudinal groove 44. The plane knife 22 therefore differs from the plane knives 21 provided for normal planing in that the part 45 containing the cutting edge 25 is wider than the other part 46, the resultant effect being that, when the plane knife 22 is attached to the plane shaft 20, the plane knife 22 protrudes far enough beyond the sole surface of the base plate 26 and the body 29 to enable rounding of a rectilinearly extending workpiece edge by means of the cutting edge 25. The handling of the planing machine 10 for rounding edges by means of a clamped plane knife 22 is in said case analogous to the handling for chamfening straight workplece edges. For said rounding machining of straight workpiece edges also, the guide and stop device 32 may be adjusted in such a way that there is an angle of approximately 45' between the sole of the base plate 26 and the body 29, on the one hand, and the workpiece surface, on the other hand.

The arc-sha,ped cutting edge 25 extends, for example, over an arc angle of at least 80'. An arc angle of 90' would actually be the normal dimension but an arc angle of less than 90' is less sensitive in the radius transition. In Figure is 3, the arc shape of the concave cutting edge 29 is selected so as to produce a circular arc extending over approximately 80' and adjoined at either end by a short tangential portion. It goes without saying that the shape of the curvature of the cutting edge 25 may be varied in diverse ways m accordance with the respective desired contours of the workpiece to be machined i the region of rectilinearly extending edges thereof An exact radius for rounding edges of the workpiece means an elliptical shape for the cutting edge 25 and vice versa on account of the rake angle of 25' to 30'. The variation follows, say, the cosine of the rake angle.

The arc-shaped cutting edge 25 has a radius lying in the region of between 1.5 mm and 8 mm. It may, for example, be advantageous to provide three differently fashioned plane knives 22 each having a concave cutting edge, e.g. a plane knife 22 with a radius of 3 mm, another with a radius of 5 mm and a 6 further one with a radius of 8 min. Said figures are however provided merely as an example.

The arc-shaped cutting edge 25 is situated at the region halfway along the length of the basic body 24 and hence at the region where the longitudinal groove 40 extends. The plane knife 22 is made of HSS material but may alternatively be made of hard metal material.

For alignment and adjustment of the plane knife 22 relative to the wedge-shaped body 29 and the latter's longitudinal groove 40 'in such a way that the cutting edge 25 is lined up with the longitudinal groove 40 and/or for adjustment of the depth of cut, before starting to round edges it is possible to use as an aid e.g. a round setting body 50, e.g. a cylindrical rod, the curvature of which corresponds e.g. to the radius of the cutting edge 25. The setting body 50 is long enough to project beyond the wedge-shaped body 29, 'in the longitudinal groove of which it fits, and to extend at least over part of the length of the base plate is 26. During the setting operation, the setting body 50 lies against the base plate 26.

The wedge-shaped body 29 is then adjusted in such a way that the setting body 50 lies also in the longitudinal groove 40. The plane knife 22 is correctly adjusted when its cutting edge 25 is in contact radially and axially, in relation to the axis 19, with the setting body 50. In the region of the handle 30, where there is a depth-of-cut scale 4 1, a radius scale corresponding to the latter may be provided, which may facifitate the adjustment of the radius curvature for rounding the edges, which adjustment is to be effected by turning the handle 30.

In the modified embodiment of a plane knife illustrated in Figure 4, identical reference characters are used for parts corresponding to the embodiment in Figure 3 so that, to avoid repetition, reference is therefore made to the description of the embodiment 'in Figure 3.

The plane knife 22a in Figure 4 is fashioned in such a way that the region 42 of the basic body 24 containing the cutting edge 25 projects above the 7 longitudinal region 45 adjoining it on either side in longitudinal direction. As a result compared to the plane knife 22 in Fig. 3 there is an even greater projection at the region 42 containing the concave cutting edge 25. A larger radius for the arc-shaped cutting edge 25 is therefore possible, which in the embodiment in Figure 4 may be e.g. 8 mm, whereas in the other embodiment in Figure 3) It is smaller, e.g. 5 mm.

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Claims

1. Plane knife for planing machines (10), in particular hand-held planing machines for machining wood, which at least along one longitudinal side (23) of its basic body (24) has a cutting edge (25), characterized in that the cutting edge (25) is formed on the nirn of an arc-shaped recess (27) of the basic body (24).

2. Plane knife according to claim 1, characterized in that the cutting edge (25) takes the form of a concave cutting edge.

3. Plane knife according to claim I or 2, characterized 'in that the cutting edge (25) is approximately semicircular in shape.

4. Plane knife according to one of claims I - 3, characterized "in that the cutting edge (25) has an approximately elliptical shape.

5. Plane knife according to one of claims I - 4, characterized in that a longitudinal groove (44) is provided at the side of the basic body (24) remote from the breast side and that the part (45) of the basic body (24) containing the cutting edge (25) and situated on one side of the longitudinal groove (44) is wider than the other part (46) extending on the other side of the longitudinal groove (44) of the basic body (24).

6. Plane knife according to one of claims I - 5, characterized in that the basic body region (42) containing the cutting edge (25) projects above the longitudinal region (45) adjoining it on either side 'in longitudinal direction.

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7. Plane knife according to one of claims I - 6, characterized in that the arc-shaped cutting edge (25) extends over an arc angle of at least 80'.

8. Plane knife according to one of claims I - 7, characterized 'in that the arc-shaped cutting edge (25) has a radius lying in the region of between 1.5 mm and 8 mm.

9. Plane knife according to one of claims I - 8, characterized in that the arc-shaped cutting edge (25) is situated on the region halfway along the length of the basic body (24).

10. Plane knife according to one of claims I - 9, characterized by its fashioning from HSS material.

11. Planing machine, in particular a hand-held planing machine, having a plane knife-carrying plane shaft (20), wherein the plane knife (21, 22; 22a) is designed in accordance with one of claims I to 10.

12. Planing machine according to claim 11, characterized by a round, e.g. cylindrical, rod-shaped setting body (50), the curvature of which corresponds to the radius of the cutting edge (25) of the plane knife (22.- 22a) and the length of which is such that, for adjustment of the plane knife (22; 22a), the setting body (50) may lie in the longitudinal groove (40) of the wedge-shaped body (29) of the planing machine (10) and project with a portion of its length from said wedge shaped body and rest against the base plate (26) of the planing machine (10), wherein in the adjusted state the cutting edge (25) of the plane knife (22; 22a) is in contact radially and axially with the setting body (50).

13. A plane knife substantially as herein described with reference to Figures I to 3 or Figures 1, 2 and 4 of the accompanying drawings.

14. A planing machine substantially as herein described with reference to the accompanying drawings.

I I Amendments to the claims have been filed as follows 1. A planing machine having a wedge-shaped body with a bottom surface which, in use, rests on a workplece, a longitudinal -groove being formed in said bottom surface which extends along substantially the entire length of the wedgeshaped body, a base plate located longitudinally behind the wedge-shaped body, a rotatable plane knife-carrying plane shaft positioned between the base plate and the wedge-shaped body, and a plane knife which is mounted in the plane shaft with one longitudinal edge projecting from the outer circumferential surface thereof such that, upon rotation of the plane shaft, the plane knife describes a circle of action which projects through an opening between the base plate and the wedge-shaped member, the plane knife having an arcuate recess in said longitudinal edge, the arcuate rim of which is formed with a cutting edge and is longitudinally aligned with said longitudinal groove in said bottom surface of said wedge-shaped body, whereby, in use, an edge portion of a workpiece may be guided in the longitudinal groove and rounded by said arcuate cutting edge of said plane knife.

2. A planing machine according to claim 1, further including a round setting body, the curvature of which corresponds to the radius of the arcuate cutting edge of the plane knife and the length of which is such that, for adjustment of the plane knife, the setting body is positioned in the longitudinal groove of the wedge shaped body so as to extend across said opening and at least partially along the base plate, the plane knife being adjusted such that the arcuate cutting edge is in radial and axial contact with the setting body.

3. A planing machine according to claim 2, wherein the round setting body is a cylindrical rod, I 4. A planing machine according to any of the preceding claims, wherein the re,Ion of said longitudinal edge of said plane knife in which the arcuate cutting edge Is formed projects above the regions adjoining of said longitudinal edge on either side thereof 5. A planing machine accord-Ing to any of the preceding claims, which takes the form of a hand-held planing machine for machining wood.

6. A plane knife for use In a planing machine according to any of the preceding claims, comprising a basic body in a least one longitudinal edge of which is formed on an arc shaped recess, the arcuate rim of which is formed as a cutting edge.

7. A plane knife according to claim 6, wherein the cutting edge takes the form of a concave cuttinor edge.

4 J 1 1 8. A plane knife according to claim 6 or claim 7, wherein the cutting edge is substantially semicircular in shape, 9. A plane knife according to any of claims 6 to 8, wherein the cutting 4 a edge has an approximately elliptical shape.

10. A plane knife according to any of claims 6 to 9, wherein a longitudinal groove is formed in one side of the basic body, distance between said longitudinal 0 edge in which said arcuate recess is formed and said longitudinal groove being greater than the distance between the longitudinal groove and the other longitundinal edge of the basic body.

1? 11, An plane according to any of claims 6 to 10, wherein the region of the longitudinal edge in which said arcuate cutting edge is formed pr Jects above the 01 adjoining regions of said longitudinal edge either side thereof 1-) A plane knife according to any of the claims 6 to 11, wherein the arc 0 shaped cutting edge extends over an arc angle of a least 80'.

13, A plane knife according to any of claims 6 to 12, wherein arc-shaped cutting edge has a radius in the range of substantially 1.5mm to 8mm.

14. A plane knife according to any of claims 5 to 12, wherein the arc shaped cutting edge is situated on the region halfway along the length of the basic body.

15, A plane knife according to any of claims 5 to 13, formed from HSS material.

16. A plane knife substantially as herein described with reference to Figures 1 to 3 or Figures 1, 2 and 4 of the accompanying drawings.

17. A planing machine substantially as herein described with reference to the accompanying drawings.

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