GB2324500A

GB2324500A - Portable planing machiine.

Info

Publication number: GB2324500A
Application number: GB9807994A
Authority: GB
Inventors: Adolf Zaiser
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1997-04-26
Filing date: 1998-04-15
Publication date: 1998-10-28
Anticipated expiration: 2018-04-15
Also published as: CN1197719A; DE19717702B4; JPH10296705A; GB2324500B; IT1299057B1; CN1098757C; DE19717702A1; GB9807994D0; ITMI980760A1

Abstract

For a portable planing machine (10) having a plane housing (12), which in a rotatable manner accommodates a plane shaft (20) provided with at least one longitudinal groove (46) serving as a plane knife holder, at least one plane knife (21), particularly in the form of a 1.1 x 5.5 mini reversible blade having at least one cutting edge (22) and a back groove (35) for the engagement of a retaining rib (37) provided in the longitudinal groove (46) of the plane shaft (20) for locking the radial position, being releasably clampable in each longitudinal groove (46), a faster and more precise tool change is made possible in that the plane knife (21) and the plane shaft (20) in the region of the longitudinal groove (46) are provided with preferably centring, latch-over retaining elements (160, 162), which lock the plane knife (21) in its axial position relative to the plane shaft (20).

Description

1 Portable 121aning machine

Background art

2324500 The invention proceeds from a portable planing machine, a plane shaft and a plane knife according to the preambles of claims 1, 9 and 14.

From EP 0 117 991 a planing machine is known having a plane shaft, which is composed of shaped discs and in the longitudinal groove of which a loose centrifugal wedge for clamping the plane knife is disposed. Exchange of the plane knife is therefore relatively easy but a precise axial alignment of the plane knife relative to the plane shaft is time-consuming and, given a lack of time, is therefore often only inadequate.

Advantages of the invention In contrast, the portable planing machine according to the invention and/or the plane shaft and/or the plane knife having the characterizing features of claims 1, 9 and 14 respectively has the advantage that, using simple means, the plane knife is quickly and precisely clampable in a consistently identical position relative to the plane shaft so as to be locked against displacement.

A plane shaft composed of axially clamped-together shaped discs and having an axial locking of the plane knife is particularly easy to manufacture owing to the fact that only a single one of the plurality of shaped discs presents a slight modification in the form of a retaining element which is worked into the contour and in particular takes the form of a resilient projection. Said slightly modified shaped disc is mountable at a specific axial position of the plane shaft and is used exclusively to retain the plane knife.

A ftuther advantage is that the plane knives according to the invention, which are provided with retaining elements for the engagement of a detent lug of the 3 0 plane shaft, may be clamped without difficulty into the previous portable planing 2 machines or plane shafts, in which case however locking of the axial position naturally only functions when there are also corresponding counterpart elements disposed on the plane shaft.

Particular advantages arise from the present invention owing to the fact that the centrifugal wedge of the plane shaft integrated m the shaped discs carries the retaining element for engagement into the plane knife and for locking the axial position, which retaining element because of the resilient arrangement of the centrifugal wedge is a latch-over element. Thus, the plane knife is retained even when the plane shaft is stationary and even with a relatively low clamping force and the axial position of the plane knife is locked in a particularly reliable manner. An unintentional lateral escape of the plane knife from the longitudinal groove of the plane shaft or even only a slight alteration of the axial position, e.g. as a result of knocks and bumps during transportation of the portable planing machine, is to be ruled out, the clamped position being releasable by pressing a screwdriver or even only a ballpoint pen with only a slight operating force against a projection of the centrifugal wedge.

Since the plane knife is a wearing part and has to be exchanged more frequently, a reduction in the time taken to clamp and precisely position the plane knife relative to tile plane shaft is extremely valuable. Said advantage arises from the cooperation of the retaining elements of the plane shaft with the retaining elements of the plane knife.

Thus, both the plane shaft and the plane knife present inventive features, the plane shaft being an important replacement part, to which the previously known plane knives Without retaining elements may also be fastened.

Drawings There follows a description of embodiments of the invention with reference to the accompanying drawings.

Figure I shows a side view of a planing machine according to the invention, Figure 2 a three-dimensional View of the plane shaft of the planing machine, Figures 3 and 4 an enlarged side view of the plane shaft according to Figure 2 in the case of maximuni radially inward and outward deflection of the centriftigal wedge (middle shaped discs without retaining elements), Figures 5 and 6 the views of the two ends of another embodiment of the plane shaft, Figures 7 and 8 enlarged views of the shaped discs with retaining element in accordance with the plane shaft construction according to Figures 5 and 6, and Figures 9 to 12 the view of a plane knife according to the invention in the form of a mini reversible blade.

Description of the embodiment

A planing machine 10 shown in side view in Figure I takes the form of a portable planing machine and comprises a machine housing 12 with a motor 1 S housing 14 and a handle 16. The handle 16 carries an electric switch 18.

In the machine housing 12, a plane shaft I I is supported so as to be rotatable about its axle 19 in the direction of the direction-of-rotation arrow 11 and carries two plane Icnives 21 With cutting edges 22, 111 front of which clamping grooves are formed in the external contour 23, indicated by dashed lines, of the plane shaft 20. When the plane shaft 20 rotates, the knives 21 with their cutting edges 22 define a circular path 24 indicated by dash-dot lines, which projects beyond the bottom surface in the form of the sole 26 of the portable planing machine 10 so that the cutting edges 22 may engage and cut into a workpiece 27 extending in alignment with the sole 26. An opening 28 disposed in the sole 26 for passage of the cutting edges 22 is closable by means of a swing-type protective hood 30. The latter automatically closes the opening 28 as soon as the portable planing machine 10 is lifted off the workplece 27. The risk of the operator being injured by the rotating cutting edges 22 is therefore reduced.

The machine housing 14 has, on either side of the plane shaft 20, 3 0 recesses 32, 34 through which the plane knives 21 in the form of reversible blades 4 with two cutting edges may be laterally removed from or inserted into the plane shaft without requiring, for clamping purposes, more than lateral insertion because the plane knives 21 are automatically clamped in readiness for operation by centrifugal wedges, described below with reference to Figure 2, when the portable plane 10 is set in operation.

The plane shaft 20 with the circular external contour 23 shown in Figure 2 is formed by a continuous stack of substantially identical shaped discs 36, 136, of which only the first seven shaped discs situated in viewing direction on the left are indicated in the drawing. Said shaped discs are mutually braced axially on a centring shaft 38 from both ends by means of clamping bodies 40, which may, for example, take the form of threaded nuts screwed onto the centring shaft 38. To reduce their weight the shaped discs 36, 136 have two opposing recesses which form the cavities 42, 44 of the plane shaft 20. The cavities 42, 44 are used for the engagement of adjusting mandrels which are used to position the shaped discs 36 relative to one another, the course of the longitudinal groove 46 being definable in a straight but alternatively oblique or helical manner. The cavities 42, 44 may also be used to receive extrudable plastic material for forming the stack of shaped discs 36. More details about the differences between the shaped disc 136 and the shaped discs 36 are provided below, in particular with reference to Figures 7, 8.

The plane shaft 20 at two radially opposing sides carries two plane laiives 2 1, which are provided in the form of thin, hard metal mini reversible blades with two cutting edges 22 and a back groove 35.

The plane knives 21 are clamped in the longitudinal groove 46 in the plane shaft 20 between a right and left groove flank 45, 47 of the radially straight groove region. Starting from the external contour 23, the longitudinal groove 46 verges with the right groove flank 45 via a longitudinal rib 3 7 (see Fig. 3), which is used for engagement into the back groove 3 5 of the plane knives 2 1, radially inwards into a transverse step 50 and from there into a rectangular, straight projection 5 1.

After the projecfion 51, the longitudinal groove 46 widens into a cavity 52 with a curved contour. Said curved contour extends in such a way that a thin region between the cavity 52 and the external contour 23 of the plane shaft forms a leaf spring 54, which verges into a centrifugal wedge 56.

The centrifugal wedge 56, 56', 56" with its catch groove 58 or with its groove flanks 57, 59 (Figs. 3, 4) embraces the projection 51 and with its radially outward-extending, straight side forms the left groove flank 47 of the longitudinal groove 46, which is adjoined in a radially outward direction by the clamping groove 25 which verges into the contour 23 of the plane shaft 20'. The groove flank 47 is disposed at such an angle relative to the opposing groove flank 45 that, in the clamped position when the centrifugal wedge 56 rests against the flat side of a plane knife 2 1, no self-locking builds up between the centrifugal wedge 56 and the plane knife 2 1, with the result that the centrifugal wedge 5 6 may, without jamming, return into its release position as soon as the plane shaft 20 is stationary and no centriffigal force prevails. Exchange of the plane knife is made much easier as a result.

The catch groove 58 delimits the radial travel of the centrifiigal wedge 56', 56" both in an mward and in an outward direction in order to avoid overstretching of the leaf spring 54.

What is not specifically shown in the drawing is that in the shaped disc 36 disposed in viewing direction on the left at the outermost end of the plane shaft 20', the longitudinal groove 46 is narrower than in the other shaped discs so that the plane knife 21 is clamped in a pincer-like manner and, when the plane shaft 20 is stationary, cannot accidentally alter its axial position or get lost. To release said preloading, a screwdriver or a matching hexagon shaft, for example, may be pushed into the cavity and under the centrifugal wedge 56 of the outermost shaped disc 36, the centrifugal wedge therefore being swivelled into its release position in which, by setting the plane shaft 20 or the plane 10 into a perpendicular position, the plane knife 21 slides out by itself from the longitudinal groove 46. Pressing lightly onto the operating projection 46' of the centrifugal wedge 56 with a pencil (not shown) is optionally sufficient to release the clamping pressure of the plane knife 2 1.

6 Figures 3 and 4 show the contour of a variant of the shaped disc 36, such as are positioned, say, in the middle or at the axially outermost end of the plane shaft 20, and a side view of the plane shaft 20 respectively.

The centrifugal wedge 56 according to Figures 3 and 4 differs from that of the previous figures in that it has a radially mwardly directed projection 46', which serves as a lever arm or as a tool application surface for swivelling the centrifugal wedge and hence releasing the preloading of the plane knife.

Figure 4 shows, by means of the solid lines, the centrifugalwedge 56" of the outer shaped disc 36, which may secure a plane knife in a preloaded manner in the longitudinal groove 46, in its normal position when the plane shaft 20" is stationary and, by means of the dashed lines, the centrifugal wedge 56 after radially downward displacement in the position of release of the plane knife.

Figures 5 and 6 show a side view of a further embodiment of the plane shaft 120 according to the invention, with both the profile of the centrifugal wedge is 156 and the arrangement of a detent lug 160 in the centrifugal wedge 156 for engagement into a recess 162 in the knife front 164 (Fig. 11) of the plane knife 21 differing from the previous embodiments. In addition, the plane shaft 120 at both ends carries in an accessible manner two eccentric screws 166 which, by being rotated approximately 90' about their longitudinal axis, draw the centrifugal wedges 156 radially Inwards and hence enable a particularly easy exchange of the plane knives 2 1.

To reduce their weight, the eccentric screws 166 are provided with a relatively large axial bore 168 and are of a hollow tubular design.

Figure 7 shows an individual shaped disc 136 for a plane shaft 120 having a detent lug 160 in the centrifugal wedge 156 for axially locIdng the plane k.nife 21 against loss or displacement.

Figure 8 shows in a cutout enlarged manner the region of the shaped disc 13 6 fitted with a plane knife 2 1, the refinement of the detent lug 160 on the left groove flank of the longitudinal groove 146 or in the centrifugal wedge 156 and the detent opening 162 of the knife front 164 of the plane knife 21 being clearly visible.

7 2 Figures 9 to 12 clearly illustrate the refinement of the plane knife 21 according to the invention, namely the arrangement of the detent opening 162 in the knife front of the plane knife 2 1, Figure 9 showing the knife back 3 9 with the back groove 35.

Two duplicate detent openings 162 are disposed one at each outer end of the plane knife 21 at diametrically opposite sides relative to the longitudinal axis so that regardless of which of the two cutting edges is inserted radially outwards into the plane shaft 12 1, they come into engagement position relative to the detent lug 160 of the plane shaft 120.

Figure 10 shows a plan view of the cutting edge 22 of the plane knife 2 1, Figure I I a view of the knife front 164 with the detent openings 162 in the form of rectangular indentations and Figure 12 the side view of the plane knife 2 1, the back groove 35 in the plane knife back 39, the cutting edges 22 and the knife front 164 with the detent opening 162 being clearly visible.

When the plane knife 21 is introduced laterally into the longitudinal groove 46 of the plane shaft 20, 20', 20" and, in the process, the centrifugal wedge 56, 56', 56" according to Figures 3, 4 is swivelled radially inwards, the clearance in the guide groove 46 is large enough to allow the plane knife 21 to be axially displaced and introduced easily, practically by simply tapping it with a finger. The clearance between the detent lug 60 and the knife front 164 is relatively slight. As soon as, during axial displacement of the plane knife 21 in the longitudinal groove 46, the detent opening 162 reaches the detent lug 60, it latches into the detent opening 162 so that the plane knife 21 is no longer displaceable in the longitudinal groove 46 without a considerable expenditure of force.

In said position, the eccentric screw 166 may be rotated out of the release position into the clamped position so that the centrifugal wedge 156 may move radially further outwards and hence finally secure the plane knife 2 1. The axial position of the plane knife 21 is therefore precisely defmed. The dimensions of the substantially rectangular detent indentations 162 of the plane knife 21 are tuned to 3 0 the detent lug 60 of the plane shaft so that upon latching of the detent lug 60 into the 8 detent opening 162, the plane knife is locked into a position without clearance relative to the plane shaft 20.

The corresponding plane knives 21 according to the invention with detent openings 162 may easily be clamped also into conventional plane shafts suitable for receiving the knives known from prior art, the axial position naturally being adjustable only by hand and in a relatively imprecise manner.

9

Claims

Portable planing machine (10) havirig a plane housing (12), which in a rotatable manner accommodates a plane shaft (20) provided with at least one longitudinal groove (46) serving as a plane knife holder, at least one plane knife (2 1), particularly in the form of a 1. 1 x 5.5 mini reversible blade having at least one cutting edge (22) and a back groove (35) for the engagement of a retaining rib (37) provided in the longitudinal groove (46) of the plane shaft (20) for locking the radial position, being releasably clampable in each longitudinal groove (46), characterized in that the plane knife (2 1), at its surface regions corresponding with the plane shaft (20), and the plane shaft (20), in the region of the longitudinal groove (46) corresponding with the plane knife (2 1), have latch-over, preferably centring retaining elements (160, 162) for locking the axial position of the plane knife (2 1) relative to the plane shaft (20).
2. Portable planing machine according to claim 1, characterized m that the plane knife (2 1) is 1. 1 mm thick, 5.5 mm high and substantially as long as the plane shaft (20) is wide and that the plane knife is made of hard metal or super-speed steel.
3. Portable planing machine according to claim 1 or 2, charactenzed M that the plane shaft (20) is made of, in particular punched, shaped discs (36, 136).
4. Portable planing machine according to claim 3, characterized in that the 2 5 plane shaft (20) has centrifugal wedges (56), which are integrated in the shaped discs (3 6, 13 6) and are used to clamp the plane knife (2 1), M particular at operating speed.
5. Portable planing machine according to claim 3 or 4, characterized in that at least one of the shaped discs (36, 136) has a projection (160) for position30 locking engagement into a recess (162) of the plane knife (2 1).
6. Portable planing machine according to claim 5, characterized in that the projection takes the form of a detent lug (160) and that the shaped disc (136) carrying said projection is disposed at the end of the plane shaft (20).
7. Portable planing machine according to claim 1, characterized in that the plane knife (2 1) close to its ends and at diametrically opposed sides relative to the longitudinal axis of the plane knife (21) carries two detent recesses (162) in the form of rectangular indentations.
8. Portable planing machine according to claim 1, characterized in that the detent recesses (162) and the projections (160) have sloping surfaces engageable in a centring manner and without clearance into one another, being designed in particular as a projection or indentation in the shape of a Mmcated cone or pyramid or the like.
9. Plane shaft for a portable planing machine according to the preamble of claim 1, characterized in that the plane knife (2 1), at its surface regions corresponding with the plane shaft (20), and the plane shaft (20), in the region of the longitudinal groove (46) corresponding with the plane knife (2 1), have preferably 20 centring, latch-over retaining elements (160, 162) for locking the axial position of the plane knife (2 1) relative to the plane shaft (20).
10. Plane shaft according to claim 9, characterized in that the plane shaft (20) is made of, in particular punched, shaped discs (36, 136).

11. Plane shaft according to claim 10, characterized in that the plane shaft (20) is provided with centrifugal wedges (56) integrated in a resilient manner in the shaped discs (3 6, 13 6) for clamping the plane knife (2 1) at operating speed.
11
12. Plane shaft according to claim 11, characterized in that at least one of the shaped discs (36, 136) has a projection (160) for engagement into a recess (162) disposed in particular at the flat side of the plane knife (2 1) and that the shaped disc (136) carrying the projection (160) in the form of a detent lug is disposed at the end 5 of the plane shaft (20).
13. Plane shaft according to claim 12, characterized m that the projection (160) is disposed in the region of the centriffigal wedge (56) of the shaped disc (136) which corresponds with the plane knife (2 1).
14. Plane knife for a portable planing machine according to the preamble of claim 1, characterized in that the plane knife (21) close to its ends and at diametrically opposing sides relative to the central longitudinal axis carries two detent recesses (162) in the form of rectangular indentations.
15. Plane knife according to claim 14, characterized in that the detent recesses (162) are disposed at the side of the knife front of the plane knife (21).
16. Plane knife according to claim 14, characterized in that the plane knife 20 (21) is 1.1 mm thick, 5.5 mm high and approximately as long as the plane shaft (20) is wide and that the plane knife is made of hard metal or super-speed steel.
17. Any of the portable planing machines substantially as herein described with reference to the accompanying drawings.
18. Any of the plane shafts for a portable planing machine substantially as herein described with reference to the accompanying drawings.
19. Any of the plane knives for a portable planing machine substantially 3 0 as herein described with reference to the accompanying drawings.