CN114382837A - Hand-held grinding machine and damping unit and/or counterweight unit - Google Patents

Abstract

The invention relates to a hand-held grinding machine (10 a; 10 b; 10c), in particular an eccentric or oscillating grinding machine, comprising: a housing unit (12 a; 12 b; 12 c); a grinding pad (14 a; 14 b; 14c) for receiving at least one grinding paper (16 a; 16 b; 16 c); an accumulator unit (18 a; 18 b; 18 c); and a damping unit and/or a counterweight unit (20 a; 20 b; 20 c). The damping and/or balancing unit (20 a; 20 b; 20c) is arranged on the housing unit (12 a; 12 b; 12c) at least for the most part on the side of the main drive axis (22a) of the grinding pad (14 a; 14 b; 14c) opposite the energy accumulator unit (18 a; 18 b; 18 c). The invention also relates to a corresponding damping unit and/or counterweight unit.

Description

Hand-held grinding machine and damping unit and/or counterweight unit

Technical Field

The present application relates to a hand-held grinding machine and a damping unit and/or counterweight unit.

Background

A hand-held grinding machine has been proposed which has: a housing unit; a grinding pad for receiving at least one grinding paper and/or at least one grinding sheet and/or at least one grinding web; an accumulator unit; and a damping unit and/or a counterweight unit for damping vibrations occurring during operation.

Disclosure of Invention

The invention proceeds from a hand-held grinding machine, in particular an eccentric or oscillating grinding machine, having: a housing unit; a grinding pad for receiving at least one grinding paper and/or at least one grinding sheet and/or at least one grinding web; an accumulator unit; and a damping unit and/or a counterweight unit, in particular for damping vibrations occurring during operation and/or for mass compensation of the mass of the energy storage unit.

It is proposed that the damping unit and/or the counterweight unit be arranged on the housing unit at least for the most part on the side of the main drive axis of the grinding pad opposite the energy accumulator unit, in particular on and/or between housing half shells of the housing unit.

The configuration according to the invention advantageously makes it possible to achieve a vibrating operation and/or a secure standing of the hand-held grinding machine. Advantageously, vibration peaks occurring in the vicinity of the grinding pad during operation can be damped and/or reduced in particular. User friendliness can advantageously be increased.

The hand-held grinding machine is provided for machining at least one workpiece by a user, in particular for grinding at least one surface of the workpiece. In order to receive the at least one grinding paper and/or the at least one grinding sheet and/or the at least one grinding web by means of the grinding pad, a hook-and-loop fastener connection can be provided. For driving the grinding pad, the hand-held grinding machine has a drive motor. For cooling the drive motor, the hand-held grinding machine has in particular at least one motor fan. The drive motor can be designed in particular as a direct current motor, in particular as a brushless direct current motor. The energy accumulator unit is provided for supplying energy, in particular electrical energy, to the drive motor. The energy storage unit comprises at least one, in particular replaceable, energy storage means and at least one receiving element, which is provided, in particular, for receiving, detachably holding and/or electrically contacting the energy storage means. An "energy accumulator" is to be understood to mean, in particular, a unit which receives, stores and releases energy, in particular chemical and/or preferably electrical energy. The energy store can be designed, in particular, as an electrochemical capacitor and/or as a fuel cell. Preferably, the energy store is designed as a battery storage, in particular as an accumulator. The energy accumulator is provided in particular for supplying energy, in particular electrical energy, for a drive motor of the hand-held power sander. Preferably, the energy storage unit, and in particular the receiving element of the energy storage unit, is designed for the detachable reception, holding and electrical contacting of different types of energy storage. The first energy store may differ from the further energy store, in particular with respect to the storage capacity of the electrical energy, in particular the storage capacity of the electrical charge, and with respect to the mass and/or with respect to the size. The grinding pad of the hand-held grinding machine is arranged on an eccentric output shaft of the eccentric transmission, which is driven by the drive motor, in particular by means of at least one rolling bearing, in particular by means of at least one radial bearing. The eccentric transmission has in particular a drive shaft which is coupled in rotation to a drive motor and can be rotated about a main drive axis. In one operating state, the grinding pad of the hand-held grinding machine can perform an eccentric rotational movement in particular. The drive motor and the eccentric transmission form in particular a drive train of the hand-held grinding machine. The hand-held grinding machine has, in particular, electronic components, in particular control and regulation electronics, for controlling the drive motor. The hand-held power sander has, in particular, at least one on-off switch, which is provided to switch on and/or off at least one operating mode of the hand-held power sander. The hand-held grinding machine may also have at least one further switch and/or a regulator, for example a rotational speed regulator, for regulating the rotational speed of the drive motor and/or the grinding pad, and/or at least one user interface, in particular a human machine interface. The housing unit forms in particular an outer housing of the hand-held grinding machine. The housing unit is provided in particular for protecting components of the hand-held grinding machine, in particular the drive motor and the eccentric transmission and electronic components, which are arranged in the housing unit, from external influences, such as dirt and/or dust and/or water. The housing unit in particular forms at least one gripping region which is provided for the user to operate and grip the hand-held grinding machine. The at least one grip region may be configured in particular as a so-called Palm-grip (Palm-hand grip) and in particular has at least one recess for at least one finger of the user. The housing unit has at least one housing element. Preferably, the housing unit has at least two housing elements fastened to one another. The housing element can be designed in particular as a housing half shell. The housing unit is produced in a suitable shaping process, preferably in a single-component or multi-component injection molding process, in particular from a plastic, preferably from a fiber-reinforced thermoplastic, particularly preferably from a glass-fiber-reinforced polyamide. The hand-held power sander has, in particular, at least one dust blower, which has at least one dust blower housing. The at least one dust blower housing is arranged in particular above the grinding pad and is delimited on the upper side by a housing unit. The at least one dust blower is provided in particular for removing dust, in particular grinding dust, which forms during operation of the hand-held grinding machine. The at least one dust fan is in particular configured independently of a motor fan of the hand-held grinding machine. The term "at least a majority" here means in particular at least 55%, advantageously at least 65%, preferably at least 75%, particularly preferably at least 85% and particularly advantageously at least 95% of the mass and/or volume fraction. "provided" is to be understood in particular to mean specially designed and/or specially equipped. The object is provided with a defined function, in particular it is understood that the object fulfills and/or executes the defined function in at least one application state and/or operating state.

The damping unit and/or the counterweight unit of the hand-held grinding machine can be designed, in particular, as a counterweight unit only, and is provided for mass compensation of the mass of the energy accumulator unit and/or for shifting the center of mass of the hand-held grinding machine. The counterweight unit comprises in particular at least one damping mass. The damping mass of the counterweight unit can be designed, in particular, only as a compensating mass for compensating the mass of the energy accumulator unit and/or for shifting the center of mass of the hand-held grinding machine. The counterweight unit, and in particular the damping mass of the counterweight unit, can be received in the housing unit and/or connected to the housing unit. The damping unit and/or the counterweight unit may be constructed in one piece with the housing unit. For example, the weight unit can be integrally injection-molded in the housing unit by a multi-component injection molding process. The counterweight unit is arranged in particular below the palm grip of the housing unit and below the motor fan in a region above and/or laterally to the dust fan housing. The counterweight unit is not arranged in particular on the grinding pad and not on the drive train and not on the motor fan and not connected to the grinding pad and/or the drive train and/or the motor fan. The counterweight unit is in particular configured differently from the handle of a hand-held grinding machine. The counterweight unit differs from the housing unit at least in particular in that the material of the damping mass of the counterweight unit differs from the material of the housing unit. Preferably, the damping mass of the counterweight unit is made of metal and/or metal alloy. A particularly secure standing of the hand-held grinding machine can be advantageously ensured by the damping unit and/or the counterweight unit being designed as a counterweight unit. In particular, it is advantageously possible to prevent the handheld grinding machine from tipping over, in particular due to the gravitational force acting through the mass of the energy accumulator unit. In particular, a low vertical position of the center of mass of the hand-held grinding machine can be achieved, in particular in the vertical vicinity of the grinding pad.

It is further proposed that the center of mass of the hand-held grinding machine, measured in particular from the lower edge of the grinding pad, lies between 45% and 75% of the total height of the hand-held grinding machine in terms of height, and that at least one straight line intersecting the grinding pad and oriented perpendicularly to the grinding pad extends through this center of mass, the minimum spacing of said straight line to the outer edge of the grinding pad being in particular between 5% and 25% and preferably between 5% and 15% of the diameter of the grinding pad. Preferably, the centre of mass of the hand-held grinding machine, measured from the lower edge of the grinding pad, lies between 55% and 65% of the total height of the hand-held grinding machine, in particular in terms of height. The minimum distance of a straight line through the center of mass which perpendicularly intersects the grinding pad is preferably between 2% and 8% and particularly preferably between 3% and 6% of the diameter of the grinding pad. This advantageously makes it possible to achieve a high level of reliability of the hand-held grinding machine. The term "diameter of the grinding pad" is to be understood in particular as meaning the diameter of the circular base of the smallest imaginary cylinder which surrounds the grinding pad just as completely.

It is also proposed that the damping unit and/or the counterweight unit comprise at least one damping mass which is arranged at least for the most part on the side of the main drive axis of the grinding pad which is opposite the energy accumulator unit. This advantageously makes it possible to achieve a high level of reliability of the hand-held grinding machine. In particular, the weight force acting through the energy accumulator unit and the resulting hand-held grinding can be advantageously compensatedDisplacement of the center of mass of the machine in the direction of the accumulator unit. Furthermore, vibrations occurring during operation of the hand-held power sander can advantageously be further reduced. The damping mass is produced in particular by casting, preferably by injection molding, in particular from at least one metal and/or metal alloy, particularly preferably from an aluminum and/or zinc injection molded part. Alternatively or additionally, the damping mass can also be produced from at least one metal and/or metal alloy in a sintering process. The mass of the damping mass can be adapted in particular to the mass of the energy store unit. The first damping mass can in particular have a defined mass and is provided in particular for operating the hand-held power sander by means of a first energy store, while the second damping mass has a mass which is different from the mass of the first damping mass and can in particular be provided for operating the hand-held power sander with a second energy store. In this regard, the damping mass may be replaceable. The geometry of the first damping mass, in particular the specific geometry having in particular specific dimensions, can at least substantially correspond to the geometry of the at least one second and/or further damping mass, in particular the specific geometry having specific dimensions. Different qualities of different kinds of damping masses with at least substantially uniform geometry can be achieved by being made of different materials with different densities. The first damper mass can be produced, for example, from an aluminum die casting for achieving a specific mass, while the other damper mass can be produced, for achieving a specific other mass, from a zinc die casting with dimensions corresponding to those of the first damper mass. The buffer mass has in particular a density of at least 6g/cm³And preferably has a density of 6.5g/cm³To 8g/cm³In the meantime. The mass of the first buffer mass may be, for example, 50 g. The mass of the second buffer mass may be, for example, 80 g.

It is also proposed that vibrations of the damper mass in a plurality of spatial directions can be made possible by at least one recess arranged between the housing unit and the damper mass. In particular, vibrations of the damper mass in all six spatial directions can be achieved by the intermediate space arranged between the housing unit and the damper mass. The damper mass can in particular be partially decoupled from a part of the housing unit. The damper mass can be excited by periodic vibrations of the housing unit occurring during operation of the hand-held grinding machine to execute periodic vibrations, in particular periodic vibrations having a frequency in the range of the resonant frequency of the damper mass. The periodic oscillation of the damper mass can be performed in particular in a phase-shifted manner with respect to the periodic oscillation of the housing unit. The phase of the periodic oscillation of the damper mass can be offset, in particular, by half the period of the periodic oscillation of the housing unit. In particular, vibrations of the housing unit occurring during operation can be reduced and preferably minimized by the periodically corresponding vibrations of the damper mass. With this configuration, vibrations occurring during operation can be advantageously damped and/or reduced particularly advantageously and easily. This advantageously allows for a high level of convenience and/or reliability and/or user friendliness. Alternatively, it is conceivable for at least one housing element of the housing unit to have at least one recess, wherein the damping mass is in particular fixedly connected to the at least one housing element and forms an outer wall, in particular the only outer wall, of the at least one housing element in the region of the recess of the housing element. The flow space in the dust blower housing can be closed, in particular hermetically, by means of at least one sealing lip. The at least one damping element of the damping unit and/or the counterweight unit can preferably be designed as a sealing lip

It is also proposed that the damping unit and/or the counterweight unit comprise at least one damping element, in particular two damping elements, by means of which the damper mass is connected to the housing unit. The at least one damping element can be configured in particular as an elastic element. The at least one damping element can be excited into elastic movement and/or deformation by vibrations occurring in the operating state of the hand-held grinding machine, whereby the movement energy of the vibrations can be converted at least partially into heat. The vibrations occurring during operation of the hand-held power sander can thereby be damped and/or reduced particularly advantageously and easily. An "elastic element" is to be understood to mean, in particular, an element which can be deformed macroscopically repeatedly without mechanical damage or damage to the element, and which returns to its original shape again, in particular after deformation. The at least one damping element can in particular be made of a synthetic material, preferably an elastomer or silicone and particularly preferably a thermoplastic elastomer. The damping mass can thereby be advantageously connected to the housing unit in a particularly simple technical manner. The at least one damping element preferably has a shore hardness of between 25 and 80 and particularly preferably has a shore hardness of between 35 and 65.

It is further proposed that the at least one damping element has at least one inner contour which is connected in a form-fitting manner to at least one outer contour of the damper mass, in particular such that the damping element can be connected to the damper mass by means of a plug connection. This advantageously makes it possible to achieve an easy connection between the damping mass and the at least one damping element. In particular, a defined force transmission of the vibrations of the housing unit to the damper mass can advantageously be achieved for a particularly suitable and effective damping of the vibrations. Advantageously, a particularly easy exchange of the damping mass can be achieved. Alternatively, it is also conceivable for the at least one damping element to be connected to the damper mass in a material-locking manner, for example by adhesive bonding.

It is also proposed that the inner contour of the at least one damping element has at least one projection, preferably a plurality of projections, and/or at least one recess, preferably a plurality of recesses, which in the assembled state rests against the outer contour of the damper mass. Vibrations occurring during operation of the hand-held power sander can be advantageously damped by this configuration. Advantageously, high-frequency vibrations, which can occur during operation of the hand-held power sander, in particular in the region of the interface, between the at least one damping element and the damper mass, can be reduced in particular further. Furthermore, manufacturing-related tolerances of the damper mass and/or the damping element can be advantageously compensated.

It is also proposed that the at least one damping element is fastened to the housing unit in a form-fitting and/or material-fitting manner, in particular by means of at least one injection molding process. In particular, for the form-fitting fastening of the at least one damping element on the housing unit, a special contour, in particular a recess, can be provided on the at least one housing element of the housing unit in the at least one receiving region, and the at least one damping element can have a corresponding contour that is adapted to the special contour of the housing unit. In particular, it is conceivable for at least one clip to extend within the housing unit between the at least one damping element and the damper mass. This advantageously results in a latching effect during the plug-in assembly, which results in a particularly robust and/or stable reception of the damping mass on the housing unit of the hand-held grinding machine. In particular, an easy mounting and/or dismounting of the at least one damping element on the housing unit can advantageously be achieved. Alternatively, the at least one damping element can be fastened to the housing unit in a material-locking manner, in particular by means of an injection molding process, preferably by means of a multicomponent injection molding process. The number of work steps for producing the damping unit and/or the counterweight unit can thereby be advantageously reduced.

It is also proposed that the housing unit has at least two housing elements which are fastened to one another in the region of the damping unit and/or the counterweight unit. The at least two housing elements of the housing unit can be connected in the region of the damping unit and/or the counterweight unit, in particular by means of at least one connecting element, in a form-fitting and/or force-fitting manner. For example, it is conceivable for the housing elements to form screw receptacles in the region of the damping unit and/or the counterweight unit and to be fastened to one another by means of screw connections. This configuration advantageously allows particularly easy assembly of the damping unit and/or the counterweight unit on the housing unit. A particularly reliable and/or robust arrangement of the damping unit and/or the counterweight unit on the housing unit can advantageously be achieved. Alternatively or additionally, the at least two housing elements may be fastened to one another in the region of the damping unit and/or the counterweight unit by means of a material-locking connection, for example by adhesive bonding. Furthermore, it is alternatively or additionally conceivable for the at least two housing elements of the housing unit to be fastened to one another in a form-fitting and/or force-fitting and/or material-fitting manner in the region facing away from the damping unit and/or the counterweight unit.

It is also proposed that the ratio between the maximum distance of the lower edge of the grinding pad to the upper edge of the damping unit and/or the counterweight unit and the diameter of the grinding pad is at most 0.4. The damping function of the damping unit and/or the counterweight unit can thereby be advantageously improved. In particular, vibrations of the housing unit which are formed in the vicinity of the grinding pad can be reduced particularly effectively. The distance between the upper edge of the damping unit and/or the counterweight unit to the lower edge of the grinding pad can be minimal in particular. Preferably, the ratio between the maximum spacing of the lower edge of the grinding pad from the upper edge of the damping unit and/or the counterweight unit and the diameter of the grinding pad is between 0.36 and 0.26. Preferably, the minimum spacing between the lower edge of the grinding pad and the upper edge of the damping unit and/or the counterweight unit is 38mm, particularly preferably 40 mm. Preferably, the maximum spacing between the lower edge of the grinding pad and the upper edge of the damping unit and/or the counterweight unit is 50mm, particularly preferably 45 mm. The minimum horizontal spacing between the outermost edge of the damping mass and the outer edge of the grinding pad is preferably between 2% and 12% and particularly preferably between 5% and 9% of the diameter of the grinding pad. This advantageously enables the user to obtain a good view of the workpiece to be machined while operating the hand-held grinding machine. The nominal diameter of the grinding pad may typically be 125mm or 150mm, but it is also conceivable that the grinding pad has a smaller or larger nominal diameter. The value of the actual diameter may in particular differ from the nominal diameter.

It is also proposed that the damping mass have at least one crown (Bombierung) which is arranged in particular in the region furthest from the energy accumulator unit and extends in particular in the direction of the grinding pad. In particular, the weight force acting through the energy accumulator unit and the resulting displacement of the center of mass of the hand-held grinding machine in the direction of the energy accumulator unit can be advantageously compensated. In particular, the efficiency of damping vibrations can be advantageously increased by the damping mass. In particular, the shape of the outer contour of the damping mass can be adapted to the shape of the housing unit. The aesthetics of the hand-held grinding machine and/or the ergonomics in the gripping area of the hand-held grinding machine and/or the ease of operation of the hand-held grinding machine can advantageously be improved. A "convex crown" is to be understood in particular as a bulging deformation. The crown can in particular be designed to be thickened and/or bent. The damping mass can in particular have an asymmetrical shape by means of the at least one crown.

It is also proposed that the damping mass is exchangeable. The damping mass can in particular correspond to a first type having a specific first mass and can be replaced and/or exchanged for a further damping mass of a second type having a specific further mass. The damping mass can preferably be exchangeable by the user, in particular without tools. The quality of the damping mass can be advantageously adapted to the individual operating situation by means of such a configuration. The mass of the damping mass can be advantageously adapted individually to the mass of the energy storage unit, in particular of the exchangeable energy storage device. Alternatively or additionally, it is conceivable that the damping function of the damping unit and/or the counterweight unit can be adapted to the operating mode by changing the damping mass, for example to the rotational speed of the grinding pad and/or to the surface roughness of the workpiece to be machined by means of a hand-held grinding machine.

It is also proposed that the housing unit has at least two mutually parallel housing faces which support the damping unit and/or the counterweight unit. The at least two parallel housing surfaces of the housing unit can support, in particular, forces acting on the damping unit and/or the counterweight unit during operation, which occur, for example, as a result of centrifugal forces. In this way, the risk of an accidental dropping of the damping unit and/or counterweight unit, in particular of the damping mass of the damping unit and/or counterweight unit, can be advantageously reduced and in particular minimized, in particular during operation, in particular even in the event of strong shaking of the housing unit. Advantageously, a high degree of user friendliness can be achieved.

It is also proposed that the center of mass of the damping mass, measured from the lower edge of the grinding pad, lies between 33% and 42% of the total height of the hand-held grinding machine in terms of height. In particular, the center of mass of the damping mass can be arranged close to the grinding pad. This configuration advantageously achieves a high standing stability of the hand-held grinding machine. The vibrations which are formed in the region of the grinding pad during operation can advantageously be damped particularly effectively.

The invention also relates to a damping unit and/or a counterweight unit for a hand-held grinding machine, having at least one damping mass.

It is proposed that the damper mass is provided for displacing the center of mass and for damping vibrations occurring during operation. With this configuration, the damping unit and/or the counterweight unit for the hand-held grinding machine can simultaneously satisfy the stabilization function of the hand-held grinding machine in addition to the damping function for damping vibrations occurring during operation of the hand-held grinding machine. Advantageously, a high degree of user friendliness can be achieved.

The hand-held grinding machine according to the invention and the damping unit and/or the counterweight unit according to the invention should not be limited to the described applications and embodiments. The hand-held grinding machine according to the invention and the damping unit and/or the counterweight unit according to the invention can have, in particular, a different number of individual elements, components and units than those mentioned here in order to fulfill the functions described here. Furthermore, in respect of the value ranges given in the publication, the values within the mentioned boundaries should also be regarded as disclosed and may be used arbitrarily.

Drawings

Further advantages can be obtained from the following description of the figures. Three embodiments of the invention are shown in the drawings. The figures and description contain several features taken in combination. Those skilled in the art will be able to appropriately view and generalize these features individually and in other combinations of significance.

The figures show:

fig. 1 schematically shows a hand-held grinding machine according to the invention, with a housing unit, a grinding pad, an energy accumulator unit and a damping unit and/or a counterweight unit,

figure 2 shows a schematic side view of a hand-held grinding machine,

figure 3 shows a schematic partial view of a housing unit,

fig. 4a shows a schematic partial view of a hand-held grinding machine, with a cutting line,

figure 4b shows a schematic cross-sectional view of the damping and/or counterweight unit and the housing unit,

figure 5a shows schematically the damping and/or counterweight unit's damping mass,

figure 5b shows in a schematic view two damping elements of the damping unit and/or the counterweight unit,

fig. 5c shows a damping unit and/or counterweight unit in a schematic view, with a damping mass and a damping element,

figure 6 shows another side view of the hand-held grinder,

fig. 7 shows an alternative configuration of the hand-held grinding machine according to the invention, with a housing unit,

fig. 8 shows a further alternative embodiment of the hand-held grinding machine according to the invention.

Detailed Description

Fig. 1 shows a hand-held grinder 10 a. The hand-held grinding machine 10a is configured as an eccentric grinder. The hand-held grinding machine 10a has a housing unit 12a, a grinding pad 14a, an energy accumulator unit 18a and a damping unit and/or a counterweight unit 20 a. An accumulator unit 18a and a damping unit and/or counterweight unit 20a are arranged on the housing unit 12 a. The housing unit 12a forms a gripping area 90a for the user to manipulate and hold the hand-held grinder 10 a. An on-off switch 80a of the hand-held grinder 10a is disposed in the grip region 90 a. The energy accumulator unit 18a is provided for supplying the hand-held grinding machine 10a with electrical energy. The energy storage unit 18a has a receiving element 74a and an energy storage device 76 a. The receiving element 74a is provided for receiving, holding and electrically contacting the energy accumulator 76 a. The energy store 76a is designed as a battery. The accumulator 76a is replaceable (see fig. 6). The energy store 76a is in electrical contact and connected to the energy store unit 18a via the receiving element 74 a. The energy supplied by the energy accumulator 76a supplies the drive motor (not shown) of the hand-held grinding machine 10a in an operating state. The drive motor drives the grinding pad 14a in an eccentric rotational movement in the operating state via an eccentric transmission (not shown). The grinding pad 14a has a circular bottom surface. The grinding pad 14a is provided for receiving the grinding paper 16 a. The grinding paper 16a is detachably connected to the grinding pad 14a by means of a hook and loop lock (not shown). Alternatively, it can be that a grinding plate (not shown) or a grinding mesh (not shown) is detachably connected to the grinding pad 14 a. The damping unit and/or counterweight unit 20a comprises a damping mass 40a and two damping elements 44 a. The damping unit and/or counterweight unit 20a includes a region 58a in which region 58a the damping unit and/or counterweight unit 20a is disposed on the housing unit 12 a. The region 58a is configured as a recess of the housing unit 12 a.

Fig. 2 shows a hand-held grinding machine 10a in a schematic side view. The damping unit and/or the counterweight unit 20a of the hand-held grinding machine 10a is arranged on the side of the main drive axis 22a of the grinding pad 14a opposite the energy accumulator unit 18 a. The damping mass 40a of the damping and/or counterweight unit 20a is arranged on the side of the main drive axis 22a of the grinding pad 14a opposite the energy accumulator unit 18 a. The hand-held grinder 10a has a center of mass 24 a. The center of mass 24a, measured from the lower edge 26a of the grinding pad 14a, is in the range of 45% to 75% of the total height 30a of the hand-held grinding machine 10a, measured from the lower edge 26a of the grinding pad 14a, in terms of the height 28 a. The center of mass 24a of the hand held grinder 10a lies on a straight line 32 a. The straight line 32a perpendicularly intersects the grinding pad 14 a. The minimum spacing 34a between the straight line 32a and the outer edge 36a of the grinding pad 14a is between 1% and 10% of the diameter 38a of the grinding pad 14 a. The center of mass 70a of the damper mass 40a, measured from the lower edge 26a of the grinding pad 14a, is in the range between 33% and 42% of the overall height 30a of the hand-held grinding machine 10a in terms of the height 72 a. The upper edge 60a of the damping unit and/or the counterweight unit 20a is disposed at a maximum distance 78a from the lower edge 26a of the grinding pad 14 a. The ratio between the maximum distance 78a and the diameter 38a of the grinding pad 14a is at most 0.4. The minimum horizontal distance 84a between the outermost edge 94a of the damper mass 40a and the outer edge 92a of the grinding pad is between 5% and 9% of the diameter 38a of the grinding pad 14 a.

Fig. 3 shows a housing unit 12a of a hand-held grinder 10 a. The housing unit 12a has a first housing element 54a and a second housing element 56 a. The housing elements 54a, 56a are configured as housing half shells. The housing elements 54a, 56a are fastened to one another in a region 58a of the damping unit and/or counterweight unit 20a (see fig. 1). The housing element 54a is fastened to the housing element 56a by means of a screw connection via a screw receptacle arranged in the region 58 a.

Fig. 4a shows a detail of a hand-held grinding machine 10a with a damping unit and/or counterweight unit 20 a. The cutting line IV is marked in fig. 4 a. The cutting lines show the cut-away course of the sectional view shown in fig. 4 b. The cutting line IV extends through the damping unit and/or the counterweight unit 20a, the housing unit 12a and the grinding pad 14 a. As can be seen from fig. 4b, the damper mass 40a is connected to the housing unit 12a by means of a damping element 44 a. A gap 42a is arranged between the damper mass 40a and the housing unit 12 a. The gap 42 enables the damping mass 40a to vibrate in a plurality of spatial directions.

Fig. 5a shows a damping mass 40a of the damping unit and/or counterweight unit 20 a. The damper mass 40a has an outer contour 48 a. The damper mass 40a has a crown 62 a. In the state in which the damping and/or counterweight unit 20a is installed in the hand-held grinding machine 10a, the crown 62a of the damping mass 40 of the damping and/or counterweight unit 20a is arranged in the region 64a furthest away from the energy accumulator unit 18a and extends in the direction of the grinding pad 14a (see fig. 1). Fig. 5b shows two damping elements 44a of the damping unit and/or counterweight unit 20 a. Damping element 44a has an inner contour 46 a. Inner contour 46a of damping element 44a has a plurality of protrusions 50a and a plurality of recesses 52 a. Fig. 5c shows the damping unit and/or counterweight unit 20a in the assembled state, with the damping mass 40a and the damping element 44 a. In the assembled state, inner contour 46a of damping element 44a is connected in a form-locking manner to outer contour 48a of damper mass 40 a. In the assembled state, the projections 50a and the recesses 52a of the inner contour 46a of the damping element 44a bear against the outer contour 48a of the damper mass 40 a.

Fig. 6 shows the hand-held grinding machine 10a with the housing unit 12a, the damping unit and/or counterweight unit 20a and the energy accumulator unit 18 a. The accumulator unit 18a comprises an accumulator 76a and a further accumulator 88 a. The energy store 76a is detachably connected to the energy store unit 18a via the receiving element 74 a. The energy store 76a is exchangeable and can be replaced by the further energy store 88 a. The further energy store 88a differs from the energy store 76a with regard to the storage capacity for supplying the hand-held grinding machine 10 a. The further energy store 88a has a higher charge than the energy store 76a in the filled state. The further energy store 88a has a higher mass than the energy store 76 a. The damping unit and/or counterweight unit 20a has a damping mass 40a and a second damping mass 86 a. The damper mass 40a is exchangeable and can be replaced by a second damper mass 86 a. The second damper mass 86a has a higher mass than the damper mass 40 a. Second damper mass 86a has the same dimensions as damper mass 40a and can be connected to housing unit 12 by means of damping element 44 a. The greater mass of the second damper mass 86a is achieved by being produced from a different material having a higher density than the damper mass 40 a. The second damper mass 86a is provided for the operation of the hand-held power sander 10a in conjunction with the further energy accumulator 88 a. After the accumulator 76a has been exchanged for the heavier further accumulator 88a, the center of mass 24a of the hand-held grinding machine 10a is moved in the direction of the accumulator unit 18 a. By replacing the damping mass 40a with a heavier second damping mass 86a, a partial compensation of the movement of the center of mass 24a can be achieved. A straight line 32a that perpendicularly intersects grinding pad 14a through centroid 24a is slightly shifted relative to the illustration in fig. 2 in the direction of energy accumulator unit 18a, but is still spaced apart from outer edge 36a of grinding pad 14a by a minimum spacing 34a (between 1% and 10% of diameter 38a of grinding pad 14 a).

Further embodiments of the invention are shown in fig. 7 and 8. The following description and the figures are substantially limited to the differences between the exemplary embodiments, wherein reference is also made in principle to the figures and/or the description of the other exemplary embodiments, in particular the exemplary embodiments of fig. 1 to 6, with regard to identically named components, in particular components provided with the same reference numerals. To distinguish between these embodiments, the letter a is placed after the embodiments of fig. 1 to 6. The letter a is replaced by letters b and c in the embodiments of fig. 7 and 8.

Fig. 7 shows an alternative embodiment 10b of a hand-held grinding machine with a housing unit 12b, an energy accumulator unit 18b and a damping unit and/or counterweight unit 20 b. The damping unit and/or counterweight unit 20b has two damping elements 44 b. The damping element 44b is fastened to the housing unit 12b by material locking. The damping element 44b is connected to the housing unit 12b by means of an injection molding process, in particular by means of a multicomponent injection molding process, in a material-locking manner. The damping element 44b has been injection molded attached to the housing unit 12 b. The first damping element 44b has been injection molded to attach to the first housing element 54b of the housing unit 12b, and the second damping element 44b has been injection molded to attach to the second housing element 56b of the housing unit 12 b. During assembly, the damping elements 44b connected to the housing elements 54b, 56b can be slipped onto the damper masses 40b, respectively, so that the damper masses 40b can be connected to the housing unit 12 b.

Fig. 8 shows a further exemplary embodiment of a hand-held grinding machine 10 c. The hand-held grinder 10c is configured as an oscillating grinder. The hand-held grinding machine 10c has a housing unit 12c, a grinding pad 14c, an energy accumulator unit 18c and a damping unit and/or a counterweight unit 20 c. The grinding pad 14c has a rectangular bottom surface. The damping unit and/or counterweight unit 20c has a damping mass 40c and two damping elements 44 c. The damper mass 40c is connected to the housing unit 12c by means of a damping element 44 c. The housing unit 12c has a first housing face 66c and a second housing face 68 c. The first housing face 66c is parallel to the second housing face 68 c. The housing faces 66c, 68c support the damping unit and/or the counterweight unit 20 c.

Claims (15)

1. A hand-held grinding machine (10 a; 10 b; 10c), in particular an eccentric or oscillating grinding machine, having:

a housing unit (12 a; 12 b; 12c),

a grinding pad (14 a; 14 b; 14c) for receiving at least one grinding paper (16 a; 16 b; 16c),

-an accumulator unit (18 a; 18 b; 18c), and

-a damping unit and/or a counterweight unit (20 a; 20 b; 20c),

it is characterized in that the preparation method is characterized in that,

the damping and/or balancing unit (20 a; 20 b; 20c) is arranged on the housing unit (12 a; 12 b; 12c) at least for the most part on the side of the main drive axis (22a) of the grinding pad (14 a; 14 b; 14c) opposite the energy accumulator unit (18 a; 18 b; 18 c).

2. The hand-held grinding machine (10 a; 10 b; 10c) according to claim 1, characterized in that a center of mass (24a) of the hand-held grinding machine, measured in particular from a lower edge (26a) of the grinding pad (14 a; 14 b; 14c), lies between 45% and 75% of a total height (30a) of the hand-held grinding machine (10 a; 10 b; 10c) in terms of height (28a), and at least one straight line (32a) intersecting the grinding pad (14 a; 14 b; 14c) and oriented perpendicularly to the grinding pad (14 a; 14 b; 14c) extends through the center of mass, a minimum distance (34a) of the straight line from an outer edge (36a) of the grinding pad (14 a; 14 b; 14c), in particular between 1% and 10% of a diameter (38a) of the grinding pad (14 a).

3. Hand-held grinding machine (10 a; 10 b; 10c) according to claim 1 or 2, characterized in that the damping and/or counterweight unit (20 a; 20 b; 20c) comprises at least one damping mass (40 a; 40 b; 40c) which is arranged at least for the most part on the side of the main drive axis (22a) of the grinding pad (14 a; 14 b; 14c) opposite the accumulator unit (18 a; 18 b; 18 c).

4. The hand-held grinding machine (10 a; 10 b; 10c) according to claim 3, characterized in that the oscillation of the damping mass (40 a; 40 b; 40c) in a plurality of spatial directions is enabled by at least one air gap (42a) arranged between the housing unit (12 a; 12 b; 12c) and the damping mass (40 a; 40 b; 40 c).

5. Hand-held grinding machine (10 a; 10 b; 10c) according to at least claim 3 or 4, characterized in that the damping unit and/or counterweight unit (20 a; 20 b; 20c) comprises at least one damping element (44 a; 44 b; 44c), in particular two damping elements (44 a; 44 b; 44c), by means of which the damping mass (40 a; 40 b; 40c) is connected with the housing unit (12 a; 12 b; 12 c).

6. Hand-held grinding machine (10 a; 10 b; 10c) according to at least claim 5, characterized in that the at least one damping element (44 a; 44 b; 44c) has at least one inner contour (46a) which is connected in a form-locking manner to at least one outer contour (48a) of the damper mass (40 a; 40 b; 40 c).

7. Hand-held grinding machine (10 a; 10 b; 10c) according to claim 6, characterized in that the inner contour (46a) of the at least one damping element (44 a; 44 b; 44c) has at least one projection (50a) and/or at least one recess (52a) which in the assembled state rests against the outer contour (48a) of the damper mass (40 a; 40 b; 40 c).

8. The hand-held grinding machine (10) according to one of claims 5 to 7, characterized in that the at least one damping element (44 a; 44 b; 44c) is fastened to the housing unit (12 a; 12 b; 12c) in a form-fitting and/or material-fitting manner, in particular by means of at least one injection molding process.

9. Hand-held grinding machine (10 a; 10 b; 10c) according to one of the preceding claims, characterized in that the housing unit (12a, 12 b; 12c) has at least two housing elements (54a, 56a) which are fastened to one another in the region (58a) of the damping and/or counterweight unit (20 a; 20 b; 20 c).

10. Hand-held grinding machine (10 a; 10 b; 10c) according to one of the preceding claims, characterized in that the ratio between the maximum spacing (78a) of the lower edge (26a) of the grinding pad (14 a; 14 b; 14c) to the upper edge (60a) of the damping and/or counterweight unit (20a, 20 b; 20c) and the diameter (38a) of the grinding pad (14 a; 14 b; 14c) is at most 0.4.

11. The hand-held grinding machine (10 a; 10 b; 10c) according to one of claims 3 to 10, characterized in that the damping mass (40 a; 40 b; 40c) has at least one crown (62a), which is arranged in particular in a region (64a) furthest from the energy accumulator unit (18 a; 18 b; 18c) and in particular extends in the direction of the grinding pad (14a, 14 b; 14 c).

12. Hand-held grinding machine (10 a; 10 b; 10c) according to any one of claims 3 to 11, characterized in that the damping mass (40 a; 40 b; 40c) is exchangeable.

13. The hand-held grinding machine (10c) according to any one of the preceding claims, characterized in that the housing unit (12c) has at least two mutually parallel housing faces (66c, 68c) supporting the damping unit and/or the counterweight unit (20 c).

14. The hand-held grinding machine (10 a; 10 b; 10c) according to any one of claims 3 to 13, characterized in that the center of mass (70a) of the damping mass (40 a; 40 b; 40c) is between 33% and 42% of the total height (30a) of the hand-held grinding machine (10a, 10 b; 10c) in terms of the height (72a), measured from the lower edge (26a) of the grinding pad (14 a; 14 b; 14 c).

15. A damping and/or counterweight unit (20 a; 20 b; 20c) for a hand-held grinding machine (10 a; 10 b; 10c) according to one of claims 1 to 14, having at least one damping mass (40 a; 40 b; 40c), characterized in that the damping mass (40 a; 40 b; 40c) is provided for displacing the center of mass (24a) and for damping vibrations occurring during operation.

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