GB2345027A - Hand-held planning machine - Google Patents

Abstract

A hand-held planing machine (10; figures 1,2) comprises a plane shaft 120 which is driven by an electric motor (15; figure 1,2). The plane shaft 120 comprises a bore 44 at one end, in which a housing-fixed journal 30 rotates, wherein at least two juxtaposed needle bearings 331,332 serve as a roller-contact bearing. Lubricant grease and/or a felt seal 291 may be disposed between a collar 31 and one of the needle bearings 331 in order to seal the bore 44 and form a lubricant depot.

Description

2345027 Hand-held planing machine The present invention proceeds from a

hand-held planing machine according to the preamble of claim 1.

A hand-held planing machine with an internally supported plane shaft is already known from EP-A 0 492 736. In said case, the plane shaft at the end face provided for rebating is supported in such a manner relative to a housing fixed axle pin that the latter engages into a central, axial bore of the end face of the plane shaft and carries the latter rotatably supported on a rolling- contact bearing.

As a result of the intemal bearing arrangement of the plane shaft the so-called rebate depth is reduced by at least the region of the rollingcontact bearing prOjecting beyond the periphery of the axle pin in comparison to hand planes, the plane shaft of which is disposed externally supported at the rebate side in the housing.

The known hand planes With an internally supported plane shaft have a tendency to become fouled in the region of the roffing-contact bearing disposed 'm the interior of the plane shaft. Furthermore, the previous internally supported plane shafts as a result of the axial fixing of the position of the axle journal relative to the plane shaft have a tendency towards static stress between the axle pin and the plane housing, wherein during operation of the hand plane alternating bending stresses in particular act upon the connection between the pin and the housing and reduce the service life of the rolling-contact bearings. What is more, the plane knife frequently has to be readjusted relative to the provided rebate edge of the plane shaft.

In contrast the invention having the features of claim 1 has the advantage that the region of the roffing-contact bearing disposed in the plane shaft 2 and of the housing is free of mechanical stresses. Furthermore, the internal bearing arrangement may be sealed better than before. As a result the dimensional tolerances for the arrangement of the axle pin relative to the housing may be increased and so the manufacturing costs of the plane may be reduced.

The service life of the bearings in the interior of the plane shaft is moreover extended and there is no longer any need for readjustment of the plane knife relative to the rebate edge.

By selecting instead of a locating bearing two non-locating bearings in the form of needle bearings, on account of the more stable, less easily tiltable axis of the needle bearings, whereby it is ensured that the needle rollers have linear instead of point contact with the running surfaces, the above- mentioned advantages are achieved and in addition the costs of the rolling-contact bearing arrangement of the plane shaft alone are reduced by around 50%.

By virtue of the fact that the plane shaft comprises juxtaposed is shaped plates which carry a centrifugal wedge for clamping the plane knives, the advantages of an inexpensive plane shaft are combined with the advantages of an extremely inexpensive bearing arrangement.

By virtue of the fact that the axle journal engaging into the plane shaft carries two needle bearings and a collar-like region at the axial outer region of the bore seals the latter in a labyrinth-like manner, with a gap width of around 0. 1 mm, said bearing arrangement is particularly insensitive to dust, especially to hardwood dust.

By virtue of the fact that the gap between the axle journal and the bore is designed as a labyrinth seal, the dustproofing is very distinctly improved.

By virtue of the fact that a lubricant depot is disposed in the interior of the bore, the sensitivity to dust of the bearing is reduced still further.

A further contributory factor is that the lubricant depot is carried and/or is sealed off In an outward direction relative to the gap by a felt seal.

3 The fact that the needle bearings are disposed in an axially displaceable manner on the axle pin enables an arrangement of the plane shaft relative to the hand plane which is stress-firee and extends the service life of the bearing.

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

The drawings show Figure 1 a side vriew of a hand plane according to the invention; Figure 2 a horizontal longitudinal section of the hand plane according to Figure 1; Figure 3 a longitudinal section of a first embodiment of a plane shaft; and Figure 4 a longitudinal section of a fluther embodiment of the plane shaft.

Figure 1 shows the side view of a hand-held planing machine 10 according to the invention, which comprises a machine housing 12 with a motor housing 14 and a handle 16. An electrical switch 18 is disposed in the handle 16.

In the machine housing 12 a plane shaft 20 is supported so as to be rotatable about its axis 19 and has knives 22 with cutting edges 23, which during rotation of the plane shaft 20 define a circle of action 24 denoted by a dash-dot line, which projects beyond the base surface designed as the sole 26 of the hand-held planing machine 10 so that the cutting edges 23 may engage and cut into a workpiece extending flush with the sole 26. Disposed m the sole -26 is an opening 28, through which the cutting edges 23 may pass and engage into the workpiece.

The horizontal longitudinal section of the hand-held planing machine according to Figure 1 which is shown in Figure 2 illustrates the parallel arrangement of a motor 15, which is disposed in the motor housing 14, relative to 4 the plane shaft 20 which is supported so as to be rotatable about the axis of rotation 19 relative to the machine housing 12.

The motor 15 on its motor shaft 42 carries a driving pinion 40, by which it is coupled via a toothed belt 38 to a toothed belt wheel 36, which is seated non-rotatably on an output shaft 34. The latter is in turn connected non rotatably to the plane shaft 20.

The plane shaft 20 at the end directed towards the output shaft 34 is rotatably supported in a rolling-contact bearing 46, wherein the outer race of the rolling-contact bearing 46 is disposed non-rotatably in a bearing seat of the machine housing 12 which is not described in detail.

At its opposite end to the output shaft 34 the plane shaft 20 is provided with an internal rolling-contact bearing arrangement particularly in the form of two needle bearings 331, 332 (Figure 3). The latter are disposed internally in a bore 44 of the plane shaft 20. Engaging axially into the plane shaft is 20 or centrally into the bearing 32 is an axle journal 30, which is connected in a non-rotatable and bending-resistant manner indirectly or directly to the housing 12, being M particular welded to the latter. Given an indirect connection, instead of the wall 12 of the housing a thicker plate is provided, which carries the axle journal 30 and is itself screw-fastened to the housing 12. As a result the - M viewing direction - right side of the hand plane 10 is usable for rebating almost as far as the outer periphery of the bottom region of the axle j ournal 3 0 and therefore has a greater rebate depth or depth of engagement than hand planes with plane shafts, which are externally supported at the rebate side or at the right side and the axle shafts of which are designed in a similar manner to the - in viewing direction - left bearing side of the plane shaft 20 of the hand plane 10 according to Figure 2. The second, axially inner-lying needle bearing additionally combats tilting of the axle journal 30 and strengthens the position of the plane shaft 20.

Figure 3 shows a horizontal longitudinal section of a plane shaft 20, which comprises axially juxtaposed, shaped individual plates which are not more specifically designated. The plane shaft 20 has a hollow cylindrical central hole 35, disposed non-rotatably in which is an output shaft 34, which carries at the - M viewing direction - left end of the plane shaft 20 a toothed belt wheel 36 and at the - in viewing direction - right end a bore 44, into which the axle journal 30 connected in a housing-fixed manner to the machine housing 12 engages. The plane shaft 20 with the output shaft 34 is mounted m an axially floating, rotatable manner relative to the axle journal 30 via needle bushes 331, 332.

The axle journal 30 in the axially outer region of the bore 44 carries a disk-like collar 3 1, which in the manner of a lid closes the bore 44 with a gap width of around 0. 1 min. lhus, the possibility of fine dust passing into the interior of the bore 44 and reaching the needle bearings 3 3 1, 3 3 2 is virtually ruled out.

The output shaft 34 may alternatively be modified in such a way that it extends only over approximately half of the length of the plane shaft 20 and is held fastinthe bore 35. In said case, the bearings 331, 332 and the axle journal are to be so dimensioned that their outside diameters are adapted to the inside diameter of the bore 35. As a result, manufacture of the plane shaft 20 is simplified.

Figure 4 shows a horizontal longitudinal section of a further embodiment of a plane shaft 120, which in its interior carries a stepped bore 35.

At the - in viewing direction - left end of the stepped bore 35 the output shaft 34 is inserted non-rotatably, while at the opposite end a coaxial bore 44 opening into the stepped bore 35 is located for embracing the outer periphery of the needle bearings 331, 332 and axially fixing the latter. The axlejournal 30 engages with its supporting region 29 centrally into the said bore. Disposed in a floating manner on said supporting region are the needle bearings 3 3 1, 3 3 2.

6 In viewing direction on the right, the needle bearings 331, 332 are adjoined in an axially outward direction by a turned groove 333 verging into a collar 3 1, which closes the entry region of the bore 44 except for a gap of 0. 1 mm. The space of the turned groove 333 delimited by the outer end face of the needle beafing 331 and the collar 31 is in said case filled with grease and/or by a felt washer 29 1. By said means, the sealing effect in the entry region of the bore 44 is enhanced and a longterm depot for the lubricant is formed.

7

Claims (8)

1. Hand-held planing machine (10) having a housing (12, 14), which carries an electric motor (15) and a plane shaft (20), which is driven by said electric motor and has in its one end face a central bore (44), into which a housing-fixed axle journal (30) engages rotatably, in particular jointly with a rolling-contact bearing (331, 332), characterized in that at least two juxtaposed needle bearings (331, 332) serve as a rollffig-contact bearing.

2. Hand-held planing machine according to claim 1, characterized in that the plane shaft (20) comprises juxtaposed shaped plates, which carry plane knives (22), which in particular are clamped by means of a centrifugal wedge.

3. Hand-held planing machine according to claim 1 or 2, characterized in that the axle journal (30) carries two needle bearings (331, 332) and that a supporting region (29) of the axle journal (3 0), which region in assembly position of the plane shaft (20) is disposed in the bore (44), has an outside diameter particularly in the form of a collar (3 1) which is approximately 0. 1 - 0.2 mm smaller than the inside diameter of the bore (44).

4. Hand-held planing machine according to claim 3, characterized in that the gap formed by the difference m diameter between the axle journal (3 0) and the bore (44) extends in the shape of a labyrinth seal.

5. Hand-held planing machine according to one of clainms 1 to 4, characterized in that a lubricant depot is disposed in the miterior of the planing shaft (20), in particular in the entry region of the bore (44) between the collar (3 1) 8 and the axiaBy outer end face of the needle bearing (33 1), preferably in the turned groove (333).

6. ' Hand-held planing machine according to claim 5, characterized m that the lubricant depot is sealed off axially in an outward direction or relative to the gap or is formed by a felt seal, parficularly in the entry region of the bore (44).

7. Hand-held planing machine according to one of claims 1 to 6, characterized in that the needle bearings (331, 332) are disposed so as to be, at least to a limited extent, axially displaceable on the axle j ournal (3 0).

8. A hand-held planing machine substantially as herein described with reference to Figures 1, 2 and 3 or Figures 1, 2 and 4 of the accompanying drawings. -