GB2419559A

GB2419559A - Sanding soleplate for a hand held sander

Info

Publication number: GB2419559A
Application number: GB0519602A
Authority: GB
Inventors: Csaba Kiss; Gustav Sieber
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2004-09-29
Filing date: 2005-09-26
Publication date: 2006-05-03
Anticipated expiration: 2025-09-26
Also published as: GB0519602D0; CN1754656A; CN1754656B; DE102004047812B4; GB2419559B; DE102004047812A1

Abstract

A hand held sanding tool with a sanding soleplate is described. The tool comprises a housing 12, accommodating a motor 24 for driving the sanding soleplate 18. The sanding soleplate 18 is located on the underside of the motor 24. A sanding plate 188 is detailed that forms part of the three-sided sanding soleplate 18 and is stepped on its underside and at the tip thereof. There is also a removable section of the sanding soleplate 180 with three equal sides that is detachably securable with a remaining portion of the sanding soleplate 181. The removable section of the soleplate 180, when attached, is flush with the non-detachable section of the soleplate 181. An elongate sanding tongue (Figure 16, 1800), detachably securable to the tip of the iron shaped sanding plate 188 may also be provided.

Description

Hand-held sanding power tool, in particular battery-driven hand-held

sanding power tool

Prior art

The present invention takes as its starting point a hand- held sanding power tool, in particular a battery-driven hand-held sanding power tool, in accordance with the precharacterising clause of Claim 1.

Battery-driven hand-held sanding power tools, usually having a plurality of relatively heavy NiCd cells as the energy store, and having the same mechanical components as corresponding hand-held sanding power tools which are connected to the mains, for example the same gear wheels, fan impellers, balancing weights to eliminate imbalances, and eccentric drives, already exist.

One disadvantage of the known hand-held power tools is their bulky overall size and their large weight, as a result of large, heavy components. This has an adverse effect on the ergonomics, handiness and manufacturing costs of the known battery-driven hand-held sanding power tools.

Advantages of the invention The invention having the features of Claim 1 has the advantage that a particularly lightweight, handy and compact battery-driven hand-held sanding power tool taking the shape of a travel iron, with a particularly high surface area output for each battery charge is produced.

Because a vertical parallel arrangement next to one another of the motor with its motor pinion and the drive shaft with its drive pinion is provided in relation to the plane of the sanding soleplate, with the flat sides of the two pinions closely adjacent to the sanding plate and running parallel thereto, the distribution of weight is moved even closer to the sanding plate and the centre of gravity of the hand-held power tool is located particularly low down.

Moreover, as a result of the vertical parallel arrangement of the motor and the drive shaft next to one another in the housing, inexpensive spur gears can be used to transmit forces or as a step-down gear with a transmission ratio of approximately i=3 between the motor and the eccentric drive, instead of the previous solutions using a toothed belt gear or - where the motor is arranged at an angle to the sanding plate - a mitre gear.

Because the motor pinion bears air baffles on one flat side, two functions are combined into one in this compact tool element, which saves space. Consequently, the motor with its motor pinion can be of particularly short construction, that is to say it has less overall axial length, the centre of gravity can be arranged particularly low down and the housing can be particularly flat in its construction. Moreover, in contrast to the previous construction with a separate motor fan, there is no need for a separate component of this kind, and the costs of materials and assembly of the battery-driven hand-held power tool according to the invention are made even more favourable.

Because the gear wheel is equipped with curved air baffles on its side facing the motor, acting as a radial fan, the motor and at the same time the motor pinion and where appropriate the drive pinion engaging therewith can be cooled with a high degree of efficiency.

Because the drive pinion is constructed to match the motor pinion and to mesh therewith, as a spur gear, and is arranged in the lowest region of the housing, the centre of gravity of the battery-driven sander is placed unprecedentedly low down.

Because the drive pinion has recesses and elevated portions on its flat sides, it simultaneously forms a particularly compact balancing weight, which may moreover be arranged to project axially beyond the sanding soleplate bearing and towards the latter, and hence very closely adjacent to the sanding soleplate - and thus of very short axial construction with the result that only small unbalancing tilting moments can occur between the sanding soleplate and the drive shaft, and the balancing weight can be kept small.

Because the drive pinion moreover bears an eccentric peg and is in particular in one piece therewith, it simultaneously forms the most important part of the eccentric drive.

Because the sanding soleplate, which takes the shape of an iron or is three-sided, has a sanding plate with a step which points towards the workpiece in the rear region and whereof the height corresponds to that of a standard hook- and-burr closure, it can receive in the region of its tip a separate three-sided sanding soleplate which is flush on its underside with the rearwardly adjoining remaining portion of the surface and at the same time carries a padding layer which extends in a plane, having the same thickness and height, with the padding layer of the rearwardly adjoining region of the sanding soleplate.

Because a narrow, elongate sanding tongue can be detachably clipped to the front, at the tip of the iron-shaped sanding soleplate, it is possible to work on even extremely small, narrow workpiece regions using the battery-driven sander, with the result that the range of applications of the battery-driven sander is widened.

Because the pressure switch of the battery-driven sander is a lever which resembles a leaf spring and may be suspended, in particular with clamping, by its lower end between the shells of the housing, the construction thereof is made particularly robust, lightweight and inexpensive.

Because the lithium ion battery undergoes virtually no self-discharge, the battery-driven sander is fully ready for use without restrictions, even after long periods in which it is not used, it being possible for it to remain in charging mode on a charging cradle between uses for as long as is required without any damage to the battery. In this connection, the charging cradle may be placed on a planar surface where it is stable and does not need to be secured, or indeed held in place when the batterydriven sander is removed. Because the battery-driven sander can make contact through its charging connector, arranged at the rear end of the housing, with counter-contacts of the charging cradle automatically when it is laid on the charging cradle without any additional cables or plugs having to be taken into account, it is always ready to be removed quickly using only one hand, there being no need to unplug a connector or remove a holder. Moreover, it is automatically ensured that the battery-driven sander will be charged up at all times.

The compact lithium ion battery, constructed in particular as a pair of batteries, is seated without play and clamped in a secure position in the upper region of the handle, integrated in the high-strength structure of the handle, and having increased dimensional stability with limited use of materials for the half-shells of the housing.

Drawings The invention will be described in more detail below with reference to an example embodiment, with the attached drawing.

In the drawing: Figure 1 shows a partly open side view of the batterydriven sander, Figure 2 shows a front view of the battery-driven sander, Figure 3 shows a bottom view of the battery-driven sander, Figure 4 shows a side view of the motor with the motor pinion, in a detail view, Figure 5 shows a side view of the eccentric drive with the sanding plate, in a detail view, Figure 6 shows a bottom view of the eccentric drive gear, Figure 7 shows a top view of the gear wheel according to Figure 6, Figure 8 shows a sectional illustration of the gear wheel according to Figures 6 and 7, Figure 9 shows a top view of the motor pinion, in a detail view, Figure 10 shows a bottom view of the motor pinion, Figure 11 shows a sectional illustration of the motor pinion, Figure 12 shows a perspective top view of the sanding soleplate, Figure 13 shows a perpendicular top view of the sanding soleplate, Figure 14 shows a longitudinal section through the sanding soleplate, Figure 15 shows a bottom view of the sanding soleplate, Figure 16 shows a perspective view of a sanding tongue, Figure 17 shows a top view of the sanding tongue, Figure 18 shows a longitudinal section through the sanding tongue, Figure 19 shows a perspective illustration of the pressure switch, Figure 20 shows a rear view of the pressure switch, Figure 21 shows a front view of the pressure switch, Figure 22 shows a cross-section through the pressure switch, and Figure 23 shows a bottom view of the housing.

Description of the example embodiment

Figure 1 shows a particularly small and compact battery- driven sander 10, whereof the housing 12 is shown open as a result of removing the right-hand housing shell 16, exposing to view the parts which are arranged in the interior of the housing 12 or in the housing shell 14, and which will be explained in more detail below.

The housing 12 is formed from two half-shells 14, 16 which may be joined together along a centre plane 15 such that they are supported against one another in sealed manner.

For this purpose, five screws reach through bores in the upper half-shell 16 (Fig. 2) into five screw casings 40, 41, 42, 43, 44 in the lower half-shell 16, in order to hold the two firmly against one another. The upper region of the housing 12 forms a domed handle region which is easy even for small hands to grasp.

At the bottom, as seen in the direction of viewing, the housing 12 carries a three-sided, iron-like sanding soleplate 18 whereof the soleplate tip 19 points to the right, as seen in the direction of viewing, and defines the recommended direction of advance. The sanding soleplate 18 has a padding layer 25 and is non-detachably secured to the housing 12, in particular being suspended, by way of two pairs of oscillating bodies 20, 22 which form four resilient pillars screwed to its outer corners.

Between the sanding soleplate 18 and the handle region of the housing 12 there is seated a motor 24 which is arranged to be vertical and may be operated by direct current. It may be operated by means of one or, in particular, a pair of lithium ion batteries 26 arranged next to one another, and is electrically connected thereto by way of electric cables 28 running through the interior of the housing 12.

Two of the electric cables 28 connect the battery 26, by way of an electronics unit 32, to a charging connector 30 which is arranged at the rear in the upper region of the housing 12, so that when this is connected, in the manner of a plug, to the counter-connector of a charger unit which is ready for operation, the battery 26 can easily be charged up. The electronics unit 32, having elements for converting alternating current into direct current and for regulating the battery charging procedure, is seated on a printed circuit board 33, fixed at the top in the handle region 17 of the housing 12.

On the right, as seen in the direction of viewing, a pressure switch 34 is arranged on the end face of or in the housing 12, and the push button 340 thereof projects outwards from an opening 35 in the housing 12, flush with the contour and readily accessible by the hand which is used to operate the device. The pressure switch 34 may be supported in actuating manner against a switching contact 361 of an electrical switch 36 by way of a contact cam 344 with the result that, when the push button 340 is pressed in, the switch 36 may be brought into the switched- on position, and when the push button 340 is released it may be brought into the switched-off position.

In its lower region, the pressure switch 34, which resembles a resilient tongue, can be fixed in corresponding central recesses in the housing shells 14, 16 by means of a positioning rib 38, with the result that it is clamped in the housing 12 in the manner of a flexible load-sensor beam and acts in resilient manner on the switch 36.

A motor shaft 46 emerges from the bottom of the motor 24, and on this a motor pinion 48 is held firmly and non- rotatably by means of its central bore 49. Arranged on the flat upper side 47 of the motor pinion 48, distributed at regular intervals, are ventilator ribs 52 in the form of curved air baffles, in particular shaped by being pressed or cast, so that the motor pinion 48 acts not only as a gear element but also as a ventilator, in particular for the purpose of cooling the motor. The motor pinion 48 has straight teeth 50 by means of which it engages with mating teeth 56 on a drive pinion 54. The flat underside 51 of the motor pinion 48 is arranged directly and closely adjacent to the lower horizontal housing wall 13 and indirectly but closely adjacent, at a spacing of less than 5 mm, to the upper side 78 of the sanding soleplate 18.

Arranged on the underside 51 of the motor pinion 48 are regular recesses 53 for the purpose of reducing the weight, and these are bridged by spokelike webs 55 to give the motor pinion 48 more than sufficient strength. The drive pinion 54 has a larger diameter than the motor pinion 48, with the result that a transmission ratio of 1=2 to 3 is produced. The teeth 56 of the drive pinion 54 fit between those of the motor pinion 48. The drive pinion 54 is mounted parallel to the motor 24 and next to the latter by means of a drive shaft 58 in the housing 12, by way of an upper and a lower drive bearing 62, 64. On its underside, the drive pinion 54 bears an eccentric 70 (Figs. 5, 6, 8) whereby it engages eccentrically 60 with the sanding soleplate 18 by way of a soleplate bearing 68, with the result that when the drive pinion 54 rotates it imparts an orbital movement to the sanding soleplate 18 by means of the eccentric 70.

At the rear, the housing 12 has a central suction removal opening 66 through which dust from sanding, formed on the underside 80 of the sanding soleplate 18 or the sanding pad 77, can be removed by suction as a result of connecting a vacuum cleaner hose (not illustrated) Figure 2 shows a front view of the battery-driven oscillating sander 10, looking towards the centre plane 15 of the motor housing 12, its half-shells 14, 16, the pressure switch 34, a transparent window 45 and the tip 19 of the sanding soleplate. The handle region 17 is narrower than the width of the sanding soleplate 18. At the top front, the motor housing 12 bears the inserted transparent window 45, which extends along the partition plane 15 and exposes to view through apertures in the half-shells 14, 16 coloured LEDs (not designated in detail) which serve in particular as a display for monitoring the charging.

Figure 3 shows the underside of the battery-driven oscillating sander 10 and the underside 80 of the sanding soleplate 18 and a sanding pad 77 (Fig. 5) which may be fixed thereto by means of a hook-and-burr closure or the like and whereof the contour is drawn in as a dashed line.

Here, the iron-shaped contour of the sanding soleplate 18 and the sanding pad 77 are visible. The sanding soleplate 18 is composed of a front sanding soleplate 180, which is removable and has three equal sides, and a fixed remaining portion of the sanding soleplate 181, which forms a regular trapezoidal surface making up the difference and which, together with the small three-sided sanding soleplate 180, forms the shape of an iron.

The sanding soleplate 18 carries an adhesive coating (not designated in detail) which corresponds to a burr-type coating on commercially available sanding pads, and which is perforated by round entry openings 777, for transporting away dust from sanding, and by four screw holes (not designated in detail) for securing the oscillating bodies 20, 22.

A corresponding sanding pad 77 may be composed of a front sanding pad 770 which has three equal sides and a rear remaining portion of the sanding pad 771, optionally separated from one another by a perforated predetermined tear line, and has eleven of the entry openings 777 for dust from sanding to pass through when it is removed by a vacuum-induced suction. The front sanding pad 770 corresponds to a standard three-sided sanding pad with curved outer sides for commercially available threesided sanders. The remaining portion of the sanding pad 771 forms a particular shape, with two parallel straight outer sides, a curved front edge which is adjacent and flush with the curved outer side of the sanding pad 770, and an outwardly curved rear edge. As a result of the remaining portion of the sanding pad 771, the effective sanding face is enlarged, so that the abrasive power of the battery-driven sander is markedly improved by comparison with known three- sided sanders with a standard three-sided sanding pad 770.

Figure 4 shows a side view of the motor 24, in a detail view, with the motor shaft 46 and the motor pinion 48 seated thereon, having the teeth 50 and the ventilator ribs 52 on its flat upper side 47. Here, it is clear that a bushing (not designated in detail) is seated in the bore 49 so that the motor shaft 46 is in non-rotatable engagement.

Figure 5 shows, in a detail view, a compact assembly comprising the sanding soleplate 18 with the drive pinion 54 engaging therewith and the output shaft 58. The drive pinion 54 engages by means of its eccentric peg 70 in a soleplate bearing 68, which is constructed as a roller bearing. This means that rotation of the eccentric peg 70 is transmitted to the sanding soleplate 18 not directly but indirectly, with the result that an orbital movement is imparted to the latter. The soleplate bearing 68 is seated in a recess, serving as a bearing seat 82, on the upper side 78 of the sanding soleplate 18. On the underside 80 of the sanding soleplate 18 there is seated a sanding pad 77 held by means of a hook-and- burr closure. The drive shaft 58 engages non-rotatably with its lower end in a central blind bore 72 on the upper side of the drive pinion 54. It is guided in an upper and a lower drive bearing 62, 64.

Figure 6 shows the underside 57 of the drive pinion 54.

Straight teeth 56 are arranged on its circular periphery, and both the upwardly pointing eccentric peg 70 and the balancing weight 74, constructed as an annular segment, are visible.

Figure 7 shows the upper side 59 of the drive pinion 54 with the central blind bore 72 and the eccentric recesses 76 which - like the balancing weight - also serve to correct imbalances.

Figure 8 shows a longitudinal section through the drive pinion 54, with the construction thereof and the fact that it is in one piece with the eccentric peg 70, the central blind bore 72, the balancing weight and the recesses 76 being apparent.

Figure 9 shows the upper side 47 of the motor pinion 48, in a detail view. Here, the central bore 49 thereof for the motor shaft 46 to pass through, the straight teeth 50 and the ventilator ribs 52 are clearly apparent.

The underside 51 of the motor pinion, shown in Figure 10, shows - in addition to the features mentioned from Figure 9 - the recesses 53 serving to save on weight and the spoke- like webs 55 which reach over them.

Figure 11 shows a longitudinal section through the motor pinion 48, in which the details mentioned above in connection with Figures 9 and 10 are particularly apparent.

Figure 12 shows a perspective illustration of the sanding plate 188 of the sanding soleplate 18, looking towards the upper side 78 thereof. Here, its three-sided shape - similar to the plate of an iron - is apparent, as is the fact that the tip 19 points forwards - also the case with an iron. Clearly apparent here are the seats 84, 86 for holding the oscillating bodies 20, 22, which may be secured thereto in particular by means of a screw or the like which may be screwed through from below. In addition to network- like ribs 89, which are annular, radial and parallel to the outer contour, broader radial ribs 85 are visible, which form the upper side of downwardly open passages 94 for the dust (Fig. 15) whereof the axial exit openings 87 are on the upper side 78 of the sanding soleplate 18 in the outer annular ribs 89. From these, any dust which is produced during sanding may be transported through a half-moon entry opening 661 (Fig. 23) in the lower housing wall 13 of the housing 12, through a duct 666 (Figs. 1, 23) formed by domed housing walls 660, to the suction removal opening 66 and away to the outside. The dust enters on the underside of the sanding soleplate 18 through eleven entry openings 777.

Figure 13 shows, by means of a perpendicular top view of the sanding plate 188 in a detail view, the details to explain Figure 12, and here the ribs 85 of the suction removal ducts 83 are more clearly visible than they were there, with their axial exit openings 87 also visible on the inside of the outermost annular rib 89. Air removed by suction flows through these, by way of the passage opening 661 in the lower housing wall 13, to the suction removal opening 66 at the rear end of the battery- driven sander 10.

Figure 14 shows a longitudinal section through the sanding plate 188, in which the underside 80 thereof forms a step 88 upwards in the front region 81. This step 88 has the same height as the hook-and-burr closure system, comprising for example a hooked layer and a burr-type layer, by means of which the three-sided sanding plate 180 is detachably secured to the sanding plate 188. This means that the padding layer 25 of the sanding soleplate 180, 181 can have a uniform thickness and can extend in a straight line, or in a plane, at the same level over the entire sanding soleplate 18. The front and rear regions 81, 91 of the sanding plate 188 are separated from one another by a step edge 90.

Figure 15 shows the underside 80 of the sanding plate 188 with the dust passages 94, which form ribs 85 on the upper side of the sanding plate 188 and terminate in the suction removal openings 87. Also present is a latching opening 92 for suspension of an additional sanding soleplate, designated a sanding tongue 1800 (Fig. 16).

Figure 16 shows the sanding tongue 1800 in a perspective illustration, its elongate sanding tip 1820, which projects a long way forward, and the coupling face 1840 being clearly apparent, it being possible Lo attach a corresponding narrow, elongate sanding pad underneath the underside 1880.

Figure 17 shows a top view of the sanding tongue 1800, with a resilient coupling tongue 1860 arranged in the centre of that edge 1910 of the coupling face 1840 closest to the tool, and when the sanding tongue 1800 is secured to the sanding plate 188, it is this, rather than the threesided sanding soleplate 180, which enters the latching opening 92 and holds the sanding tongue 1800 firmly against it.

Lateral abutment edges 1900 on the coupling face 1840, for positioning and holding the sanding tongue 1800 against the sanding plate 188, ensure that there is a firm coupling connection with no play.

Figure 18 shows a longitudinal section through the sanding tongue 1800, and shows that its underside 1880 is planar and is provided for receiving corresponding elongate, narrow sanding pads.

Figure 19 shows a detail, illustrated in perspective, of the pressure switch 34 formed in the manner of a leaf spring. Its shell-shaped push button 340 is arranged in the upper region and provided with an end face 341 curved at the front. This ensures comfortable handling. It is adjoined downwards by the resilient body of the pressure switch 34, which in the upper region, between the push button 340 and the resilient body 343, carries oblique reinforcing ribs 348.

The rear side 342 of the push button 340 is hollow, because of the shellshaped construction, and points towards the interior of the housing. The resilient body 343 bears on its rear side a contact cam 344 which serves to provide access to the switching contact of the switch 36.

In the lower region, the resilient body bears a transversely extending pin-like region which serves as a positioning rib 38 and holds the pressure switch 34 firmly, clamped non-detachably and without play, in corresponding recesses in the housing shells 14, 16 of the housing 12.

Figures 20 to 22 show the pressure switch from the rear, from the front, and in longitudinal section, providing an explanation of the statements relating to Figure 19.

Figure 23 shows the underside of the battery-driven sander 10 with the sanding soleplate removed, the half-moon entry opening 661 being clearly visible in the centre with respect to the centre plane 15 - in both halfshells 14, 16 - behind the eccentric peg 70 and the soleplate bearing 68.

Moreover, the underside of the front and rear oscillating bodies 20, 22, which are arranged in pairs, is exposed to view.

Claims

Claims 1. A hand-held sanding power tool, in particular a battery-driven

sander, having a housing (12) which receives a motor (24) for driving the sanding soleplate (18) and on the underside whereof a sanding soleplate (18) is arranged, characterjsed in that a sanding plate (188) which forms the three-sided sanding soleplate (18) is constructed to be stepped on its underside and at the tip thereof a removable sanding soleplate (180) which has three equal sides is detachably securable, with a remaining portion of the sanding soleplate (181), which enlarges the surface and is in particular non-detachably seated on the sanding plate (188), adjoining the sanding soleplate (180) to the rear and with the edges flush.
2. A hand-held sanding power tool according to Claim 1, characterised in that the remaining portion of the sanding soleplate (181) has two parallel straight outer sides, a rear outwardly curved side and a front inwardly curved side which is delimited with the edges flush with the sanding soleplate (180)
3. A hand-held sanding power tool according to Claim 1 or 2, characterised in that the three-sided sanding soleplate (180) and the remaining portion of the sanding soleplate (181) form a common planar support surface and have a planar padding layer (25) which merges flush with one another and is of uniform thickness.
4. A hand-held sanding power tool according to Claim 1, 2 or 3, characterised in that the sanding soleplate (18) has in particular eleven radial dust passages (94) which pass through the sanding plate (188) at a small angle from below on the outside, obliquely upwardly and inwardly, whereof the dust entry openings (777) are made on the underside (80) and whereof the exit openings (87) are made on the upper side in an annular rib (89), and whereof the side walls form ribs (85) on the upper side (78)
5. A hand-held sanding power tool according to one of Claims 1 to 4, characterised in that at the front a narrow, elongate sanding tongue (1800) can be detachably clipped to the tip of the iron-shaped sanding plate (188).
6. A hand-held sanding power tool according to one of Claims 1 to 5, characterised in that the motor (24) and a drive shaft (58) are arranged in the housing (12) parallel next to one another and perpendicular to the sanding plate (18) and are in rotary connection with one another by way of gearing means (48, 54), with the gearing means (48, 54) arranged at the bottom in the housing (12)
7. A hand-held sanding power tool according to Claim 6, characterjsed in that the gearing means, which in particular take the form of a pair of straight-toothed gear wheels, are constructed from two gear wheels (48, 54)
8. A hand-held sanding power tool according to Claim 7, characterised in that the gear wheels (48, 54) are arranged pointing downwards towards the sanding soleplate (18) and closely adjacent thereto such that their flat sides (47, 51, 57, 59) extend substantially parallel to the sanding soleplate (18)
9. A hand-held sanding power tool according to Claim 8, characterised in that one of the gear wheels serves as a motor pinion (48) and bears air baffles (52) on its flat upper side (47) facing the motor (24), for generating cooling air or suction air.
10. A hand-held sanding power tool according to Claim 8 or 9, characterised in that the motor pinion (48) is in the form of a radial ventilator.
11. A hand-held sanding power tool according to one of Claims 6 to 10, characterised in that the other of the gear wheels (48, 54) serves as a drive pinion (54), engaging in the sanding soleplate (18) and bearing at least one balancing weight (74) and/or a balancing bore (76)
12. A hand-held sanding power tool according to Claim 11, characterised in that the balancing weight (74) and/or the balancing bore (76) are arranged on Opposing flat sides (57, 59) of the drive pinion (54)
13. A hand-held sanding power tool according to Claim 12, characterised in that the balancing weight (74) is in the form of an annular segment and is seated on the underside of the drive pinion (54).
14. A hand-held sanding power tool according to Claim 13, characterised in that the drive pinion (54) bears, on the side with the balancing weight (74), an eccentric peg (70) which is in particular in one piece therewith, for the purpose of engagement in the sanding soleplate (18)
15. A hand-held sanding power tool according to Claim 9, characterised in that the balancing weight (74), which is in the form of an annular segment, extends approximately over half the length of the eccentric peg (70) and parallel thereto, in particular at the same time concentrically surrounding the eccentric peg (70)
16. A hand-held sanding power tool according to Claim 1, characterised in that a pressure switch (34) for switching the motor (24) on and off is in the form of a part which is similar to a leaf spring and is actuable by flexing.
17. A hand-held sanding power tool according to Claim 16, characterised in that the pressure switch (34) may be non-detachably clamped in the housing, by means of its lower end.
18. A hand-held sanding power tool according to Claim 16 or 17, characterised in that the pressure switch (34) is in the form of a convexly curved push button (340) at its upper end.
19. A hand-held sanding power tool according to one of Claims 1 to 18, characterised in that a charging connector, arranged at the rear end of the housing (12), may make contact with counter-contacts of a charging cradle when it is in the charging position, without any additional cables or plugs having to be actuated.
20. A hand-held sanding power tool substantially as herein described with reference to the accompanying drawings.