EP3246127B1 - Manually operated machine tool with a positioning spring assembly - Google Patents

Description

The invention relates to a hand machine tool, in particular a grinding machine, according to the preamble of claim 1.

Such a hand machine tool in grinding machine is for example in DE 10 2007 010 195 B3 or US 6,722,967 B1 explained.

A machining head of a hand machine tool in the form of a grinding machine is shown in, for example DE 10 2007 012 394 A1 in the form of a grinding head can pivot gimbally relative to the rod-shaped handle element forming a grip rod, so that the operator can comfortably guide the grinding head along wall surfaces in order to grind them.

However, the handling of such a grinding machine is inconvenient in some cases. In particular, the positioning of the machining head or grinding head relative to the wall surface is difficult in some work situations because of the long handle bar.

It is therefore the object of the present invention to provide an improved hand machine tool, in particular a grinding machine.

To solve this problem, a hand machine tool according to the technical teaching of claim 1 is provided.

The advantage of this concept is that the grinding head or machining head is loaded into a starting position or base position by the positioning spring arrangement, so that it is defined, but flexible, relative to the handle element Position. Starting from this base position, the operator can easily position the machining head relative to the wall surface. The grinding work is easy to do by hand.

If several suction hoses or other lines, for example drive shafts, are provided for the line arrangement, for example two suction hoses, the positioning spring arrangement is separate from all suction hoses. A positioning spring arrangement should advantageously be understood to mean a spring arrangement which is provided for springing or spring loading the machining head into the base position relative to the handle element.

One embodiment of the invention therefore expediently provides that the positioning spring arrangement comprises at least one leg spring. But it is also possible that the positioning spring arrangement comprises a rubber buffer and / or a plastic buffer. Furthermore, a helical spring is also possible as part of the positioning spring arrangement. Any combination is easily conceivable, i.e. for example a leg spring strikes a rubber or plastic buffer so that the spring effects add up. However, a rubber buffer can also be effective parallel to a helical spring.

The positioning spring arrangement yields when processing the subsurface or a workpiece surface, so that the operator can comfortably guide the processing head along the workpiece surface.

The machining head assumes the basic position when it is not loaded by external forces, for example by the action of an operator or a force that acts back on the hand machine tool, for example from the workpiece.

The positioning spring arrangement is preferably arranged away from the line arrangement. It is preferred if the positioning spring arrangement does not act directly on the line arrangement and / or acts separately from the line arrangement on the machining head.

The positioning spring arrangement is expediently not in direct force engagement with the line arrangement.

The positioning spring arrangement is advantageously not penetrated by the line arrangement.

The positioning spring arrangement is expediently spatially spaced from the line arrangement.

The positioning spring arrangement advantageously does not act on the machining head via the line arrangement, in particular not via a suction hose.

The drive motor is preferably arranged directly on the machining head.

It is advantageous if a gear via which the tool holder is driven is arranged directly on the machining head. The transmission can comprise or be, for example, an eccentric transmission and / or a speed-changing transmission, in particular a speed of the drive motor reducing, in particular a toothed transmission and / or a transmission generating a hypercycloid movement of the tool holder.

It is also possible that the drive motor is arranged, for example, on the handle element and the tool holder on the machining head directly or via a power transmission arrangement, for example with a cardan shaft a gear, in particular a gear provided on the machining head, drives. For example, the power transmission arrangement comprises a flexurally flexible power transmission element, in particular for transmitting a rotary movement of the drive motor to the tool holder or an upstream gear. This force transmission element expediently forms part of the line arrangement.

The positioning spring arrangement can be assigned to one or more degrees of freedom of movement of the machining head relative to the handle element or be effective in relation to one or more degrees of freedom of movement. For example, it is possible that the base position of the machining head can only be adjusted with respect to a degree of freedom of movement, in particular a degree of swivel movement or degree of freedom of rotation, by the positioning spring arrangement, while at least one other degree of freedom of movement, for example at least one degree of translational freedom and / or at least one degree of freedom of rotation, of the Positioning spring arrangement is unaffected.

A respective positioning spring is supported on the one hand on a component fixedly or movably connected to the handle element and on the other hand on the machining head or a component fixedly or movably connected to the machining head.

At this point it should be mentioned that, of course, with several degrees of freedom of movement that the machining head has relative to the handle element, for example with several pivot axes and / or with a combination of pivot axis and sliding axis, a positioning spring arrangement or a component thereof can be assigned to each degree of freedom of movement. It is possible, for example, that with multi-axis pivotability, for example two-axis pivotability, of the machining head relative to the handle part, at least two pivot axes or a positioning spring or positioning spring arrangement is assigned to each pivot axis, so that the machining head is relatively assumes a stationary central position or base position for the handle element in relation to both pivot axes.

A preferred embodiment of the invention provides, however, that the positioning spring arrangement does not act in relation to every degree of freedom of movement of the machining head relative to the handle element. The processing head is expediently mounted movably by a first degree of freedom of movement relative to the handle element by means of the joint arrangement, for example mounted so as to be pivotable about a first pivot axis, the positioning spring arrangement being effective in relation to this first degree of freedom of movement, while in relation to at least a second degree of freedom of movement, for example a pivoting mobility a second pivot axis of the machining head, the positioning spring arrangement has no effect.

It is preferred if the machining head is loaded by the positioning spring arrangement in the direction of the base position with respect to a pivot axis which runs transversely, in particular at right angles, to a longitudinal axis of the handle element. With this configuration in particular, it is advantageous if the machining head is not loaded by the positioning spring arrangement in the direction of the base position or is freely movable with respect to a pivot axis that runs in a plane with a longitudinal axis of the handle element or is aligned with the longitudinal axis. With regard to a longitudinal extension or longitudinal axis of the handle element, the processing head can advantageously be moved freely, for example, be mounted in a pendulum manner, while it is transversely, in particular at right angles, transversely to this longitudinal axis or longitudinal extension or a plane in which the longitudinal extension or longitudinal axis runs through the positioning spring arrangement is charged to the base position.

The line arrangement can be used, for example, to transmit electrical energy. The electrical energy is used, for example, to supply power to a drive motor of the machining head. However, the electrical energy can also be a very small amount of energy, namely an energy for data transmission. Furthermore, the line arrangement can be used to transmit mechanical energy serve, for example, to transmit a rotational force from a drive motor, which is arranged on the handle element, to the machining head. For example, the line arrangement then comprises a flexible rotating shaft. A suction hose can be provided to pass a suction flow through. Dust, dirt or the like can be extracted from the area of the machining tool via the suction hose.

The handle element preferably has a longitudinal shape. The handle element extends along a longitudinal axis or has a longitudinal axis. The handle element protrudes from the processing head in relation to the longitudinal axis or in the direction of the longitudinal axis.

An energizing device for energizing the drive motor is expediently arranged on the handle element.

With regard to the joint arrangement with which the machining head and the handle element are movably mounted with respect to one another, several variants are possible, for example at least one sliding bearing, at least one pivot bearing or both.

An embodiment is preferred, which is shown in the drawing, in which the joint arrangement comprises a pivot bearing arrangement. The joint arrangement can also be formed by a pivot bearing arrangement. On the basis of the pivot bearing arrangement, the machining head is mounted so as to be pivotable relative to the handle element about at least one pivot axis. A pivot bearing arrangement with a first and a second pivot bearing, the pivot axes of which are angled to one another, is preferred. For example, the first and second pivot axes of the two pivot bearings are at right angles to one another. A cardanic pivot bearing arrangement or a cardanic bearing is preferred.

The joint arrangement preferably comprises at least one sliding bearing for linear adjustment of the machining head relative to the handle element. It For example, it is possible for the processing head to be adjustable relative to the handle element along a longitudinal axis of the handle element.

It is preferred if the positioning spring arrangement comprises a first positioning spring and a second positioning spring, which act on the machining head in opposite directions and / or opposite sides in the direction of the base position. The positioning springs therefore act from different sides or in different directions of action, so to speak, in the direction of a central position, namely the base position. It is possible for the first and second positioning springs to act on the machining head with mutually opposite torques. For example, the positioning springs act on the machining head in opposite directions of rotation or directions of rotation.

At least one positioning spring expediently extends at least partially ring-shaped or ring-shaped around a pivot axis about which the machining head can pivot relative to the handle element. Two such positioning springs are preferably provided, one of which acts on the machining head in a first direction of rotation and the other positioning spring acts on the machining head in a second direction of rotation opposite to the first direction of rotation.

It is expediently provided that the first positioning spring and the second positioning spring, which act in opposite directions and / or opposite sides in the direction of the base position, are arranged on separate and / or spaced apart bearings, in particular pivot bearings and / or sliding bearings. For example, the first positioning spring can be arranged on a first pivot bearing and the second positioning spring on a second pivot bearing. The machining head is expediently arranged between the pivot bearings. For example, it is possible that the two positioning springs are each penetrated by other axle elements or axle pieces.

It is also expedient if the positioning spring arrangement is arranged, in particular directly, on at least one bearing of the joint arrangement. According to the invention it is provided that the positioning spring arrangement comprises at least one positioning spring which is supported directly on bearing elements of the joint arrangement.

The bearing elements are, for example, components of a bearing for pivoting or displacing the machining head relative to the handle element in relation to a first pivot axis or sliding axis. For example, such a positioning spring, in particular a leg spring, is supported on the one hand on a support arm or fork arm of the joint arrangement, which is described in more detail below, and on the other hand on a bearing element firmly connected to the machining head or movably mounted on the machining head. The bearing element movably mounted on the machining head can, for example, be a bearing element which, in turn, is movable with respect to the machining head about a further pivot axis or sliding axis. The bearing element connected to the handle part can, for example, be part of a pivot bearing, by means of which the machining head can be pivoted about a first pivot axis relative to the handle element.

In principle, however, it is also possible for a positioning spring to be supported directly on the one hand on a base body of the machining head and on the other hand on a component of the joint arrangement or the handle element.

An arrangement of a positioning spring outside a bearing of the joint arrangement or next to a bearing is also easily possible. Such a positioning spring arranged outside the bearing can be provided in addition to a positioning spring arranged inside a bearing.

It is advantageous if a positioning spring or all positioning springs of the positioning spring arrangement is completely or partially enclosed in a housing, for example the bearing housing explained below. One arranged in this way The positioning spring is protected against damage and / or environmental effects or the like, for example.

The integration of at least one positioning spring in a bearing of the joint arrangement, in particular in a bearing housing, is advantageous. It is preferably provided that at least one of the bearing elements on which a positioning spring is supported has a bearing housing in which the at least one positioning spring is completely or at least partially housed. For example, the bearing housing comprises a receiving sleeve for the positioning spring. In particular, a leg spring can advantageously be accommodated in such a receiving sleeve.

It is advantageous if at least one positioning spring, for example a leg spring or torsion spring, extends in a ring around at least one pivot axis of the joint arrangement.

An expedient embodiment provides that at least one bearing element, on which a positioning spring is supported, comprises a bearing shaft part, e.g. a bearing pin, or that a bearing shaft part is arranged on the bearing element, on the outer circumference of which the positioning spring is arranged or which engages in the positioning spring. The bearing shaft part or the bearing pin can, however, also penetrate the positioning spring. In combination with the embodiment explained above, it is possible, for example, for the positioning spring, in particular a leg spring, to be penetrated by the bearing shaft part or bearing bolt and to be arranged in a receiving sleeve of at least one bearing element.

It is advantageously provided that the joint arrangement comprises a fork which protrudes from the handle element. The processing head or a bearing element, which in turn is fixedly or articulated to the processing head, are advantageously held or arranged between fork arms of the fork.

It is advantageous if the fork arms of this fork extend approximately parallel to the longitudinal axis of the handle element.

A fork base or a fork foot of the fork is expediently firmly connected to the handle element, for example a handle bar or handle bar part.

It is preferred if the fork has a passage on its fork foot or fork base for the line arrangement which runs between the handle element and the processing head. For example, the fork base or the fork foot is designed as a type of clamp for clamping a profile part and / or an end region of the handle element.

The fork arms, in any case at least one fork arm, are preferably reinforced with a rib structure.

The fork expediently serves to support the positioning spring arrangement, in particular one or all of the positioning springs of the positioning spring arrangement, with respect to the handle element. The respective positioning spring is therefore supported on the one hand on the fork, in particular its fork arms, and on the other hand on the machining head. The respective positioning spring is thus supported close to the machining head.

The respective positioning spring is preferably not supported on a connection area of the fork with the handle element on the fork.

The respective positioning spring is advantageously supported on the fork at an end region of the fork facing the machining head, in particular at free end regions of the fork arms.

The following angular relationships are advantageously provided between the handle element and the machining head in the basic position.

In the base position, on the one hand a longitudinal axis of the handle element and on the other hand an axis of rotation of the tool holder and / or a machining plane of the machining tool intended for machining a workpiece or a floor plane or foot plane of the machining head are expediently arranged at an angle to one another, which have the following areas can. The angle is preferably in a range between 0 ° and 90 °. A somewhat narrower angular range of, for example, 20-70 ° is preferred. In practice, an angle range of approx. 30-60 ° has proven to be advantageous. Furthermore, in some cases it is also advantageous if the angle is in a range of approx. 25-40 °. A basic setting at an angle of approx. 30 ° is advantageous. At these angles, for example the angle of approximately 30 °, the machining head is therefore inclined at an angle relative to the longitudinal axis of the handle element. The machining plane, for example a loop plane or grinding surface of the machining tool, is oriented, for example, at an angle of 30 ° or one of the other angles mentioned above to the longitudinal axis or longitudinal direction of the handle element, in particular designed as a handle bar. So if the operator holds the handle at an angle of about 30 ° or another of the above-mentioned angles obliquely to a vertical wall surface to be machined, the machining plane of the machining tool is parallel to the wall surface.

A swivel range of the machining head relative to the handle element is limited, for example, to approximately 180 °, in particular 120 °, preferably approximately 90-110 °. For example, the machining head can be pivoted between a first and a second deflection position, which at the same time represent maximum positions. The base position set by the positioning spring arrangement lies between the deflection positions. It goes without saying that these maximum positions do not have to be defined by fixed stops, but that the maximum positions or maximum deflection positions can also represent resilient stops or resilient end positions. For example, the positioning spring arrangement can have a stop in the maximum deflection positions or represent a resilient stop. However, the already mentioned line arrangement between the handle element and the processing head can also form a fixed or resilient stop device for limiting a pivoting path or movement path of the processing head relative to the handle element.

Starting from the base position, the machining head can expediently pivot into a first deflection position in which the axis of rotation of the tool holder is approximately at right angles to the longitudinal axis of the handle element. In the first deflection position, the processing plane of the processing tool, for example a grinding plane of a grinding plate or an underside of a grinding plate, can be parallel or approximately parallel to the longitudinal axis of the handle element. Starting from the base position, the machining head can preferably pivot through approximately 30 ° into a first deflection position.

In a second deflection position opposite to the first deflection position in relation to the base position, the machining head is deflected, for example, by approximately 60 ° to 80 ° from the base position or base position. In the second deflection position, for example, an axis of rotation of the tool holder is approximately parallel to the longitudinal axis of the handle element. The machining plane, in particular a grinding plane, of the machining tool is preferably approximately at right angles to the longitudinal axis of the handle element in the second deflection position.

For example, the line arrangement comprises a suction hose for sucking off chips, dust or the like generated by the machining tool. The suction hose is expediently elastic or flexible in bending. The suction hose can have a resilient effect.

In addition to or as an alternative to the suction hose, the line arrangement can also comprise an electrical line for the transmission of electrical energy from the handle element to the machining head. Such a line arrangement, which has one or more electrical lines, can also have a certain spring effect on the machining head, proceeding from the handle element.

The positioning spring arrangement expediently counteracts a spring action of the line arrangement which loads the machining head relative to the handle element. If, for example, the line arrangement per se acts on the machining head from the base position, the positioning spring arrangement acts in the sense of compensation. This compensation can be implemented in Be provided with respect to one or more degrees of freedom of movement of the machining head relative to the handle element.

However, it is also possible that the spring action of the line arrangement and the spring action of the positioning spring arrangement jointly load the machining head in the direction of the base position. For example, it is possible that the line arrangement loads the machining head in a first pivoting direction with respect to a pivot axis and a positioning spring of the positioning spring arrangement acts in this first pivoting direction. A second positioning spring can also act in the first pivot direction or also against the first pivot direction, that is, in a second pivot direction. An embodiment has already been explained in which positioning springs act in mutually opposite directions of rotation or with opposite directions of rotation between the handle element and the machining head.

It is also advantageous if the positioning spring arrangement has a higher spring force and / or a higher spring constant with respect to the machining head compared to the line arrangement. The positioning spring arrangement thus acts on the machining head with a higher force than the line arrangement, so that ultimately the spring force of the positioning spring arrangement is decisive for the positioning of the machining head in the base position.

An advantageous embodiment of the invention provides that the joint arrangement is oriented towards a center or a focus area of the machining head.

It is advantageously provided that at least one pivot axis, preferably two pivot axes or all pivot axes of the joint arrangement, run through a center of gravity area or a central area or a center of the machining head.

At least one line of the line arrangement, for example a suction hose, or the line arrangement as a whole is expediently articulated to the machining head outside of the center or middle region thereof. It is thus possible, for example, for the machining head to be mounted movably with respect to the handle element in the area of its center by means of the joint arrangement and for lines to lead from the handle element to the machining head outside the center. The line arrangement thus counteracts this eccentric load, for example eccentrically on the machining head and the positioning spring arrangement.

It can also be provided that the drive motor on the machining head is arranged eccentrically with respect to a pivot axis, in particular a pivot axis running transversely, preferably at right angles, to the longitudinal axis of the handle element. Particularly in this context, but also with other eccentric weight loads, it is advantageously provided that the positioning spring arrangement compensates for an eccentric and / or eccentric weight load on the machining head with respect to a pivot axis, in particular by the drive motor. The positioning spring arrangement therefore places the machining head in the base position against a weight load on the machining head that does not act in the center.

At this point it should be mentioned that the positioning spring arrangement acts on the processing head in the direction of the base position, but weight forces - depending on the respective center of gravity of the processing head - act on the processing head depending on its relative position in space, so that the positioning spring arrangement with different forces against gravity acts in the direction of the base position, but the machining head can assume different angular positions and / or sliding positions relative to the handle element depending on its respective center of gravity.

One embodiment of the invention can provide that the suction connection and the drive motor are arranged on opposite sides of a swivel axis, in particular a swivel axis running transversely to the longitudinal axis of the handle element, and the positioning spring arrangement is applied differently to the processing head by the suction hose and the drive motor acting forces relative to the handle element compensated or equalized so to speak.

It is advantageously provided that the joint arrangement has a first pivot axis and a second pivot axis which are angled to one another, in particular at right angles. It is advantageous if the first pivot axis runs transversely, in particular at right angles, transversely to a longitudinal axis of the handle element and the second pivot axis and the longitudinal axis of the handle element are arranged in a common plane or planes parallel to one another. The first pivot axis runs transversely to this plane or these planes, for example at right angles. As a result, a cardan bearing is implemented, for example

One embodiment provides that a first pivot axis of the joint arrangement running transversely to a longitudinal axis or longitudinal extension axis of the handle element runs between the longitudinal axis of the handle element and a second pivot axis of the joint arrangement running transversely to the first pivot axis of the joint arrangement, for example at right angles.

It is advantageously provided that one or the first pivot axis running transversely to a longitudinal axis of the handle element is further away from the tool holder than one or the second pivot axis of the joint arrangement running transversely, in particular at right angles, to the first pivot axis of the joint arrangement. The second pivot axis runs, for example, directly on an upper side of the machining tool or the tool holder, so that the machining head and thus the machining tool can pivot, in particular oscillate, about this second pivot axis. As a result, the guiding behavior of the machining head is favorable. The second pivot axis is therefore relatively close to the workpiece. The second pivot axis is a so-called X-axis, for example.

It is advantageous if the positioning spring arrangement moves the machining head with respect to the first pivot axis or a transverse axis to the longitudinal axis of the handle element running pivot axis loaded into the base position. With regard to the second pivot axis or a pivot axis parallel to the longitudinal axis of the handle element, the machining head is expediently unloaded or at least only loaded by a possible force from the line arrangement. The processing head can thus oscillate or pivot relatively freely about the second pivot axis or pivot axis parallel to the longitudinal axis of the handle element, while it is loaded into an initial position, namely the base position, with respect to the first pivot axis by the positioning spring arrangement.

An advantageous embodiment of the invention provides that the suction connection is arranged in the base position between the end area of the handle element and the articulation area of the processing head.

The handle element can have an elongated shape on its underside and / or an underside surface extending at least in a longitudinal axis. The machining side of the machining head is preferably elongated and / or has a machining surface extending in a longitudinal axis. A processing surface is preferably provided on the processing side of the processing head, for example a grinding surface, polishing surface or cleaning surface.

The base position can be a single relative position of the machining head and the handle element. However, it is preferred that the base position forms part of a base work area or a base position area containing at least one or more base positions. In the basic work area, ie in a larger area, for example pivoting and / or sliding area of the machining head and the handle element relative to one another, the underside of the handle element and the machining side of the machining head are arranged, so to speak, on the same side of the hand machine tool. This is made clearer, for example, by the following explanations:
The machining head can be deflected, for example pivoted and / or displaced, from the base position. It is possible, for example, for an underside surface of the handle element and a processing surface provided on the processing side of the processing head to be parallel or approximately parallel to one another in a parallel position. About parallel is to be understood as a small angular range of a maximum of 10 °, in particular a maximum of 5 ° or 3 ° from a position in which the underside surface and the processing surface are exactly parallel. The parallel position can be the corresponding base position. However, it is also possible that the base position forms part of a base work area, for example a swivel area. For example, the processing surface can pivot out of the parallel position in at least one direction, for example towards the underside of the handle element and / or away from the underside of the handle element.

In other words, it is quite possible that a processing surface on the processing side, for example a grinding surface or polishing surface, is penetrated by a longitudinal axis of the handle element approximately at right angles, in particular in a range of 80-120 °.

In the base position or the base work area, the suction hose does not extend beyond the articulation area to a front area of the processing head facing away from the handle element. The suction hose can be shorter. The suction hose is better protected against damage. The suction hose is therefore preferably not arranged on a front, free end region of the machining head facing away from the handle element, but rather on a rear region of the machining head assigned to the handle element.

A favorable arrangement provides that the suction hose runs, protected at least in sections, next to a support arm which protrudes from the handle element and on which the processing head is held. Thus, a free section of the suction hose, which, for example, does not run in a tube or other profile element of the handle element, is also arranged next to the support arm and thus protected. An arrangement with several support arms, for example two support arms, as also implemented in the following exemplary embodiment, is favorable.

It is expediently provided that a fork is arranged on the end region of the handle element holding the processing head, which fork has fork arms on which the processing head is held and between or next to which the suction hose runs. The suction hose is therefore preferably arranged in an intermediate space between the fork arms. However, it is also possible for the suction hose to be arranged laterally next to the fork arms, outside the space between the fork arms. The fork arms protect the suction hose from damage. However, it is possible that the suction hose still protrudes in sections in front of the fork arms, for example upwards or downwards from an intermediate space between the fork arms. The fork arms are, for example, support arms.

It is possible for a section or several sections of the suction hose to protrude, for example, upwards or downwards in front of the fork arms or the already mentioned support arm or fork arms. For example, in the base position of the processing head, the suction hose has a curved section which protrudes in front of one side of the support arm or the fork arms. A section of the suction hose protruding to another side, for example downwards, in front of the fork arms or the aforementioned support arm, is connected, for example, to the suction connection of the processing head.

An advantageous embodiment of the invention provides that the suction hose is fixed on the end region of the handle element and / or on the suction connection in a tensile or non-sliding manner, or both. A configuration is advantageous in which the suction hose is rotatable, for example, with respect to the handle element or the suction connection. This can improve the freedom of movement or mobility of the machining head.

However, due to the favorable course of the suction hose between the articulation area of the processing head and the handle element, the mobility of the processing head relative to the handle element is also given to a high degree when the suction hose is fixed immovably on the processing head and / or on the handle element.

The suction hose is expediently made of rubber and / or elastic plastic. The suction hose can be provided with ribbing or other reinforcement, for example a spiral reinforcement or a support spiral.

It is preferred if the suction hose is connected to the handle element in alignment with a longitudinal axis or direction of longitudinal extent of the handle element. It is furthermore advantageous if the suction hose is fixed on the machining head, for example at right angles to a machining plane or grinding plane of the machining tool or, in another formulation, parallel to an axis of rotation of the tool holder. It is therefore advantageously provided that a longitudinal axis of the first hose end of the suction hose extending approximately in the direction of flow of the suction flow is aligned with a longitudinal axis of the handle element extending along a longitudinal extension of the handle element and / or a longitudinal axis of the second hose end of the suction hose extending approximately in the flow direction of the suction flow is approximately parallel to an axis of rotation of the tool holder or approximately at right angles to a machining plane or grinding plane of the machining tool on the machining head.

In terms of greater flexibility, the following measure can be. It is advantageously provided that the suction hose has two oppositely curved sections between the handle element and the suction connection of the machining head. The curved sections of the suction hose that are preferably provided between the handle element and the suction connection run in opposite directions. For example, the suction hose can have the shape of a question mark or an S-curve. This curved course can be seen in each position of the processing head can be provided relative to the handle element. However, it is also possible that such a curved course is only provided in predetermined positions of the machining head relative to the handle element, for example in a base position or starting position that the machining head assumes when it is not loaded by an external force.

An advantageous embodiment provides that the articulation area of the machining head is provided between the suction connection and the drive motor. This results in a particularly favorable weight distribution. On the one hand the suction hose and on the other hand the drive motor put a strain on the machining head. The suction hose can help to balance the weight. The suction hose can, for example, compensate for a force component with which the processing head is supported on the handle element. The suction hose can contribute to a balance of the processing head relative to the handle element. Furthermore, with this configuration or as a result of this it can also result that the suction hose does not run over the drive motor in the base position of the processing head.

The machining tool has, for example, a circular outer circumferential contour and / or expediently a circular machining side or machining surface.

It is preferably provided that the suction connection is arranged outside a center of the machining head and / or the machining tool. For example, the suction connection is arranged outside a circle center point of a substantially or exactly circular outer circumferential contour of the machining head.

The suction connection is advantageously arranged eccentrically, in particular as far eccentrically as possible, on the machining head.

The suction connection is preferably arranged on an edge area or outer peripheral area of the machining head, for example a motor housing or a suction hood of the machining head.

The hand machine tool preferably has a handle bar with a longitudinal axis or comprises such a handle bar, the suction hose running in the connection region with the end region of the handle element along this longitudinal axis. For example, a flexible suction hose can be arranged on the handle bar. It is also possible, however, for the handle element to have a rigid tubular body in which a suction channel that is in flow connection with the suction hose to the processing head runs. The tubular body can be designed, for example, as a profile tube, in particular as a rigid profile tube. In this case, the tubular body is suitable for gripping by the operator. The profile tube therefore forms a support body or a load-bearing component of the handle element.

The handle element expediently has at least one suction channel which runs in the direction of a longitudinal axis of the handle element, for example in the above-mentioned flexible suction hose or the tubular body, and opens out at the end of the handle element at its end region facing the processing head. There the suction hose is connected to the processing head with the suction channel.

However, the handle element is preferably designed as a suction tube at least at its end region facing the machining head or has a suction tube. The suction hose, which leads to the processing head, is connected to this suction tube.

The hand machine tool is preferably a grinding machine, polishing machine or milling machine. In particular, the hand machine tool is preferably equipped with a handle element that protrudes from the machining head or motor housing.

The handle element can be in one piece or in several pieces. The handle element is preferably or comprises a handle bar. The handle bar can be a one-piece component or has a plurality of bar sections which are detachable from one another and / or can be moved relative to one another by means of bearings, so that the handle bar for example, when not in use, can be disassembled and / or folded into a compact shape.

Figur 1

eine perspektivische Darstellung einer Schleifmaschine, von der in

Figur 2

ein Bearbeitungskopf, beispielsweise ein Schleifkopf, perspektivisch dargestellt ist,

Figur 3

eine Seitenansicht der Schleifmaschine mit in einer Basisposition befindlichem Bearbeitungskopf, der in Teilansichten gemäß

Figur 4

in einer ersten, aus der Basisposition verstellten Auslenkposition und

Figur 5

in einer zweiten, aus der Basisposition verstellten Auslenkposition dargestellt ist,

Figur 6

eine Seitenansicht des Bearbeitungskopfs,

Figur 7

eine Explosionsdarstellung eines Antriebs des Bearbeitungskopfs der Schleifmaschine,

Figur 8

den Bearbeitungskopf der Schleifmaschine mit einer Gelenkanordnung in Explosionsdarstellung,

Figur 9

die Gelenkanordnung der Schleifmaschine in Explosionsdarstellung,

Figur 10

einen Antriebsmotor der Schleifmaschine mit einer Schutzschaltungen in Explosionsdarstellung,

Figur 11

einen Querschnitt durch den Antriebsmotor gemäß Figur 6 etwa entlang einer Schnittlinie A-A,

Figur 12

einen oberen Abschnitt eines Motorgehäuses des Bearbeitungskopfs schräg von hinten,

Figur 13

eine perspektivische Schrägansicht von oben auf eine Motorbaugruppe des Bearbeitungskopfs mit dem Antriebsmotor, von dem in

Figur 14

eine Querschnittsansicht, etwa entlang einer Schnittlinie F-F in Figur 13, dargestellt ist,

Figur 15

eine Ansteuerschaltung für den Antriebsmotor,

Figur 16

Griffstabteile eines Griffstabs für die Schleifmaschine in noch nicht gestecktem Zustand perspektivisch von schräg oben,

Figur 17

die Anordnung gemäß Figur 16, jedoch im gesteckten Zustand,

Figur 18

perspektivische Detaildarstellungen der in den Figuren 16 und 17 dargestellten Griffstabteile.

An exemplary embodiment of the invention is explained below with reference to the drawing. Show it:

Figure 1

a perspective view of a grinding machine, of which in

Figure 2

a machining head, for example a grinding head, is shown in perspective,

Figure 3

a side view of the grinding machine with the processing head located in a base position, the partial views according to FIG

Figure 4

in a first deflection position adjusted from the base position and

Figure 5

is shown in a second deflection position adjusted from the base position,

Figure 6

a side view of the processing head,

Figure 7

an exploded view of a drive of the processing head of the grinding machine,

Figure 8

the processing head of the grinding machine with a joint arrangement in an exploded view,

Figure 9

the joint arrangement of the grinding machine in an exploded view,

Figure 10

a drive motor of the grinding machine with a protective circuit in an exploded view,

Figure 11

a cross section through the drive motor according to Figure 6 approximately along a section line AA,

Figure 12

an upper section of a motor housing of the machining head obliquely from behind,

Figure 13

a perspective oblique view from above of a motor assembly of the machining head with the drive motor, of which in

Figure 14

a cross-sectional view, approximately along a section line FF in Figure 13 , is shown,

Figure 15

a control circuit for the drive motor,

Figure 16

Handle bar parts of a handle bar for the grinding machine in the not yet inserted state, perspective from obliquely above,

Figure 17

the arrangement according to Figure 16 , but when plugged in,

Figure 18

perspective detailed representations of the Figures 16 and 17 handle bar parts shown.

The exemplary embodiment relates to a hand machine tool 10 in the form of a grinding machine, although other embodiments of hand machine tools are also possible with regard to some partial aspects of the following description, for example milling machines, polishing machines or the like. Furthermore, in the exemplary embodiment, an elongated handle element is shown, which can definitely be shorter or longer. The hand machine tool according to the drawing is advantageous for working on ceilings or walls. The hand machine tool 10 according to the drawing can also be referred to as a ceiling and / or wall grinding machine. Aspects of the following statements do not necessarily relate exclusively to grinding machines, polishing machines or milling machines, but can also be used with other hand machine tools.

The hand machine tool 10 has a processing head 11 which is articulated on a handle element 12 by means of a joint arrangement 13, In the present case, it is not slidable, which would be possible in principle, but around at least one pivot axis, and in the specific exemplary embodiment even around two pivot axes. The handle element 12 is designed in the shape of a rod. It has a longitudinal extension or longitudinal axis L. The elongated handle element 12 enables the machining head 11 to be guided along a workpiece surface O of a workpiece W, for example a wall surface, at a great distance from the user.

The joint arrangement 13 supports the machining head 11 with respect to the handle element 12 by means of a first pivot bearing 14 about a first pivot axis S1 and by means of a second pivot bearing 15 about a second pivot axis S2. Using the pivot bearings 14, 15, the machining head 11 can pivot about the two pivot axes S1 and S2 relative to the handle element 12, the pivot axes S1 and S2 being at right angles to one another. In principle, however, angles other than right angles would also be conceivable. The pivot bearings 14, 15 advantageously form a cardan bearing.

The pivot axis S1 runs transversely, in the present case at right angles, to the longitudinal axis L of the handle element 12. The pivot axis S2 and the longitudinal axis L are advantageously arranged in a common plane or in planes parallel to one another. The pivot axis S2 and the longitudinal axis L do not intersect in the present case.

The machining head 11 has a support body 16 on which a drive motor 17 is held. The drive motor 100 drives a tool holder 19 about an axis of rotation D either directly or in the present case via a gear 80. The tool holder 19 is provided for holding a machining tool 20 which, when mounted on the tool holder 19, can be driven to rotate by the drive motor 100. The tool receptacle 19 comprises, for example, a plug-in receptacle, bayonet contours, a screw thread or the like, other assembly means known per se for assembling a machining tool.

At this point, however, it should be mentioned that instead of or in addition to the rotary movement of the tool holder 19, an oscillating movement, for example, is also possible in another configuration of an exemplary embodiment. Furthermore, it is also possible to implement superimposed rotary movements, for example hypercycloid rotary movements, of the tool holder 19, the gear 80 then being configured differently, for example having an eccentric gear.

In the present case, the machining tool 20 is a grinding tool, in particular a grinding plate. The machining tool 20 can contain several components, for example a grinding plate on which a grinding wheel or a grinding sheet can be arranged. For this purpose, for example, a Velcro connection between the sanding pad and the sanding sheet is advantageous.

With the machining tool 20 configured as a grinding tool, the hand machine tool 10 forms a grinding machine 10A. The machining head 11 could also be referred to as a grinding head. The elongated, rod-shaped handle element 12 facilitates the machining of surfaces remote from the operator, for example wall surfaces. The hand machine tool 10 preferably forms a wall and / or ceiling grinder. However, the configurations explained below are also advantageous in the case of a large number of differently configured hand machine tools, in particular grinding machines, but also saws, drills or the like.

The tool holder 19 and consequently the machining tool 20, when it is fastened to the tool holder 19, are preferably arranged under a cover of the machining head 11. It would be possible, for example, for the cover 21 to cover the machining tool 20 over its entire outer circumference and top. In the present case, a cover 22 that is movable with respect to the cover 21 is provided, for example on a front, free region of the machining head 11 facing away from the handle element 12. The cover 22 is, for example, removable from the cover 21 and / or mounted movably relative to the cover 21 by means of a bearing, for example around one of the Swivel axis S2 parallel swivel axis. A plug-in assembly of the cover 22 on the cover 21 provides, for example, plug-in projections 22B, for example plug-in tabs, which can be inserted into plug-in receptacles 21B of cover 21, in particular can be latched to plug-in receptacles 21B.

A seal 22A, that is to say sealing elements, for example brushes, sealing lips or the like, other sealing elements that preferably adapt to the workpiece surface O, can be provided on the outer edge region of the cover 21, 22. It is possible that the machining tool 20 protrudes in front of the seal 22A.

The cover 21, 22 is fastened, for example, to an underside of the support plate or the support body 16 or is integral with the support body 16. On an upper side, ie facing away from the tool holder 19, a motor housing 24 for the drive motor 100 and a suction connection 23 are arranged on the support body 16.

An air inlet or an inflow opening 25 for admitting cooling air cooling the drive motor 100 is arranged on the upper side of the motor housing 24 facing away from the tool holder 19. The cooling air K flows out of the motor housing 24 via an air outlet region 18 of the motor housing 24, for example. For example, the air outlet area 18 is located in an area that is angled to the inflow opening 25, for example on the outer circumference of the motor housing 24. In principle, it would be possible for the cooling air K to flow as far as the area enclosed by the covers 21, 22 and there, for example, contribute to cooling the machining tool 20 or also to loosening dust.

The air outlet region 18 extends both in a working direction AR to the front and laterally thereto, for example over an angular range of approx. 90 ° in each case to the side of the working direction AR. The cooling air K can therefore blow free a work area AB extending in the working direction AR to the front and laterally to the working direction AR.

Via the suction connection 23, dust, dirt or chips can be sucked off from the area covered or covered over by the covers 21, 22. The suction connection 23 has a connecting piece 23A, for example.

A suction hose 26 with a hose end 28 is connected to the suction connection 23, the other hose end 27 being connected to the handle element 12.

The connection of the hose ends 27, 28 to fixed structures, for example the suction connection 23 and the handle element 12, is improved by structuring 29, for example corrugations, on the hose elements 27, 28. To fasten the hose end 28 to the suction connection 23, a clamp 30 is provided, for example, which can be brought into a clamping position that jams the hose end 28 with the connector 23A by means of a screw 30A. At the other end of the hose 27, for example, a sleeve-shaped connection part 31 and a connecting piece 32 for connection to a rod-shaped channel body 33 of the handle element 12 are provided, so that a suction stream S laden with dirt flowing out of the suction connection 23 can flow into a flow channel 34 of the handle 33.

A handle part 35 and, on the other hand, the machining head 11 are arranged on mutually opposite longitudinal end regions 12A and 12B of the handle element 12. The handle part 35 is preferably used for gripping by an operator.

The rod-shaped, elongated channel body 33 extends between the joint arrangement 13 and the handle section 35 of the handle element 12. The handle section 35 is arranged between the channel body 33 and a channel body 36, on which a suction connection 37 for connecting a suction hose C is provided. The suction hose C can be connected to the channel body 36 using a fastening arrangement 38, for example. The fastening arrangement 38 comprises, for example, a clamp, a hook arrangement or the like.

A switch 39 for switching on the drive motor 100 is provided on the handle section 35.

In the area of the handle part 34, an energization device 40 for energizing an excitation coil arrangement 120 of the drive motor 100 is arranged.

The energizing device 40 can be connected to an electrical supply network V or some other power source via a mains cable N, which can be arranged, for example, on the suction hose C or integrated into the suction hose C. The other power source can be, for example, a battery pack or some other energy storage device that can be on board the hand machine tool 10.

Via diodes D1, D2, D3 and D4 of a rectifier G, the energizing device 40 can, for example, generate a direct voltage UG to ground or a base potential U0 from an alternating voltage provided by the supply network V in a known manner, with a capacitor C1 advantageously between the potentials UG and U0 , for example a smoothing capacitor or intermediate circuit capacitor, is arranged.

An output stage E, e.g. a commutator, is connected to lines with the potentials U1, U0 and provides excitation currents I1, I2 and I3 for the drive motor 100 via lines L1, L2 and L3. The output stage E includes, for example, pairs of switches with electronic power switches, for example MosFETs, V1, V2 and V3, V4 and V5, V6, between which the lines L1, L2 and L3 are connected in the manner of half bridges.

The switches V1-V6 are controlled by a controller 170 via control lines (not shown). The controller 170 monitors the current flow on the line L1 using a current monitoring device 171, for example. Further current monitoring devices, for example for lines L2 and L3, could easily be provided. The current monitoring device 171 has, for example, a corresponding inductance in order to detect the current flow on the line L1.

The controller 170 expediently includes a control program 173 which includes program code that can be executed by a microcontroller 172 of the controller 170. By executing this program code, the controller 170 can control the switches V1-V6 in a suitable manner in order to set a speed and / or power output of the drive motor 100 via a corresponding current flow on the lines L1 to L3. However, the switching behavior of the switches V1-V6 can also be an indication for the controller 170 that no more current is flowing via one or more of the lines L1 to L3.

The line arrangement 41 comprises an electrical cable 42 in which the lines L1, L2 and L3 are arranged. The cable 42 runs from the handle portion 35 in the channel body 33 or on the outside of the channel body 33 and opens out of the channel body at its end region facing the machining head 11. From there, the cable 42 runs freely to the drive motor 100.

A housing 43, in which the energizing device 40 is arranged, is provided on the handle portion 34. The energization device 40 expediently also has mechanical components, for example coolant, in addition to the power electronic components. The energization device 40 therefore has a certain weight, which, however, does not interfere with the operation of the handheld power tool 10. The energizing device 40 is namely arranged directly on the handle portion 34, where the operator regularly grips the handle element 12 with at least one hand. With regard to the electrical drive technology, only the drive motor 100 acts in the sense of a lever on the handle section 34, while the preparation of the electricity for the drive motor 100 is, so to speak, with a favorable center of gravity directly in the handle area of the handle element 12.

The arrangement of the comparatively dirt-sensitive or dust-sensitive electronics in the handle section 34 also has the advantage that it is as far away as possible from an area of the hand machine tool 10 where dust occurs, namely on the processing head 11 Air flowing into the housing 43, which is preferably also conveyed to a particular extent by coolant, for example a fan 45, is not very dusty because of the great distance from the machining tool 20.

The fact that the drive motor 100 and the suction connection 23 are arranged on opposite sides of an articulation region 46 of the machining head 11, the joint arrangement 13 being articulated to the machining head 11 at the articulation region 46, contributes to favorable handling of the hand machine tool 10. The suction hose 26 has curved sections between the free end of the handle element 12, where it is connected to it, and the processing head 11, in particular two curved sections 47, 48 curved in opposite directions, so that it comfortably follows the movements of the processing head 11 relative to the handle element 12. This becomes clear in the Figures 3, 4 and 5 .

The tool holder 19 is arranged on a machining side BS of the machining head 11. In a base position B of the machining head 11 relative to the handle element 12, the machining side BS and an underside UH of the handle element 12 face the workpiece W.

Starting from the base position B ( Figure 3 ) the machining head 11 can move between deflection positions A1 ( Figure 5 ) and A2 ( Figure 4 ) sway. The deflection positions A1, A2 are expediently maximum positions, with pivoting beyond these deflection positions A1, A2 being entirely possible. If the suction hose 26 is to be deflected or deformed to an even greater extent beyond the deflection positions A1 and A2, it expediently forms a resilient stop for the deflection positions A1 and A2.

The base position B, together with the deflection positions A1 and A2 and possibly further deflection positions beyond these deflection positions or intermediate deflection positions between the deflection positions A1 and A2, forms part of a basic work area B of the hand machine tool 10. It is pivoting beyond the deflection position A2 that the edit page BS and an upper side of the handle element 12 facing a workpiece W are entirely possible. The machining head 12 is then located, for example, in an additional work area ZA.

In the deflection position A1, for example, a machining plane E of the machining tool 20 runs approximately parallel to the longitudinal axis L, while in the deflection position A2 the machining plane E is approximately at right angles to the longitudinal axis L.

On the end region of the handle element 12 holding the processing head 11, in this case the channel body 33, a fork 50 is arranged, between the fork arms 51, 52 of which the processing head 11 is pivotably mounted about the pivot axis S1. The fork arms 51, 52 are designed on a holding section 53 in the manner of half-shells, between which a holder 54 or a receptacle for the handle element 12, in particular its channel body 33, is formed.

The holder 54 is formed, for example, between walls 55 of the fork arms 51, 52, for example as a round receiving contour. Support structures 58 of the fork 50, which can be formed in particular by the screw domes 57, serve to prevent rotation and / or displacement with respect to the longitudinal axis L of the handle element 12. Support structures 33A of the handle element 12 engage in the support structures 58, for example form-fit projections, for example recesses, in particular grooves or longitudinal recesses, provided on the outer circumference of the channel body 33. The support structures 58, 33A act as an anti-twist device and / or a security device against displacement with respect to the longitudinal axis L of the handle element 12.

As a strain relief for the cable 42, it is advantageous if a cable clamp 49 is provided on the fork 50. The cable clamp 49 has, for example, clamping bodies provided on each of the fork arms 51, 52 which, when the fork arms 51, 52 are joined together to fix the holding element 12, simultaneously clamp the cable 42.

The fork arms 51, 52 are reinforced in particular at their arm sections 60A, 60B protruding in front of the holding section 53, for example by a rib structure 59.

The fork arms 51, 52 have between the holding section 53 and their free ends 61 angled portions 62, 63 between the arm sections 60A, 60B. The angled portions 62, 63 preferably serve to optimally design the space between the fork arms 51, 52 and the movement space below the fork arms 51, 52 for the machining head 11.

The bends 62 run opposite one another in the sense of a widening or widening of a distance between the ends 61. As a result, there is an increased room for movement between the fork arms 51, 52, in particular in the area of the suction hose 26 and the suction connection 23.

The bends 63 run in the same direction next to one another, but starting from the handle element 12 and with respect to the longitudinal axis L away from the machining head 11 in one direction and towards the free ends 61 again towards the machining head 11 or the longitudinal axis L, so that in particular for the deflection position A1, for example accordingly Figure 8 , or there is a further deflection beyond the deflection position A1, a space BW below the fork arms 51, 52 for an upper section of the machining head 11.

At the free ends 61 designed as bearing receptacles bearing elements 64 for bearing shaft parts 65 of the pivot bearing 14 are provided. The bearing shaft parts 65, which are designed, for example, in the manner of bearing bolts, are, for example, screws or other similar bolts that penetrate the bearing receptacles of the bearing elements 64 and penetrate into bearing elements 68 designed as bearing projections.

The bearing elements 68 are provided on a bearing body 75 and project in front of a cross member 77 of the bearing body 75. The bearing body 75 is designed, for example, as a type of bearing shaft or bearing projection. For example, the Bearing elements 68 are provided on the respective longitudinal end regions of the cross member 77. A support bearing section 78, which is for example arcuate, extends between the traverse 77 and the support body 16.

The support bearing section 78 forms part of the pivot bearing 15 for pivoting about the pivot axis S2. The support bearing section 78 is penetrated by a bearing shaft 76, which in turn is received in bearing receptacles 79 of bearing blocks 79A, which protrude in front of the support body 16. The support bearing section 78 is arranged between the bearing blocks 79A. Of course, instead of the bearing shaft 76, bearing bolts could also be provided which, for example, are received in the bearing body 75, in particular rotatably, penetrating the bearing receptacles 79. Thus, the pivot axis S2 is closer to the support body 16 than the pivot axis S1, so that the machining head 11 can pivot about the pivot axis S2 located correspondingly close to the machining plane E. The machining head can easily follow the course of the workpiece surface O.

The machining head 11 oscillates or pivots freely with respect to the pivot axis S2, the suction hose 26 and the line arrangement 41 dampening or braking the pivoting movement. However, it must be taken into account here that the suction connection 23 is close to the pivot axis S2 or is penetrated by the pivot axis S2, which accordingly little restricts the pivotability of the machining head 11 about the pivot axis S2.

In relation to the pivot axis S1, on the other hand, a positioning spring arrangement 70 is provided, which acts in the processing head 11 in the base position B. The positioning spring arrangement 70 comprises positioning springs 71, 72 directly supported on the bearing elements 64, 68. The positioning spring 71 is assigned to the fork arm 51, while the positioning spring 72 is assigned to the fork arm 52. The positioning springs 71, 72 act on the machining head 11 in opposite directions, ie one positioning spring 71 acts on the machining head 11, for example with respect to the pivot axis S1, in a clockwise direction, while the other positioning spring 72 acts on the machining head 11 in a counterclockwise direction. Thus, the machining head 11 is held in a central position, so to speak, in relation to the pivot axis S1, namely the base position B.

The positioning springs 71, 72 are supported with support arms 73 on support receptacles 67 of the bearing elements 64 and support receptacles 67B on the bearing elements 68. The positioning springs 71, 72 are, for example, leg springs, the longitudinal ends of which are designed as support arms 73.

The bearing elements 68 penetrate the positioning springs 71, 72. Support contours 69, for example ribs, are expediently provided on the outer circumference of the bearing elements 68, on which the positioning springs 71, 72 can be supported with their inner circumference. The ribs or support contours 69 expediently run parallel to the pivot axis S1. As a result, the mobility of the positioning springs 71, 72 and the bearing elements 68 relative to one another is particularly good.

The positioning springs 71, 72 are expediently protected and enclosed. They are advantageously received in bearing housings 66, 74 which are provided by the bearing elements 64, 68. For example, the bearing housings 66, 74 are complementary to one another or fit into one another in the manner of sleeves or plug-in elements in order to enclose the positioning springs 71, 72 as a whole. As a result, the bearing components and in particular also the positioning springs 71, 72 do not get dirty. In addition, the risk of injury from any protruding elements, for example the support arms 73, is low.

The support receptacles 67 are provided, for example, on the bearing housings 66 of the bearing elements 64. The support receptacles 67B are provided on the bearing housings 74 at the bearing elements 68.

It goes without saying that a positioning spring arrangement can also be provided with respect to the pivot axis S2, which aligns the machining head 11 to the handle element 12 with respect to the pivot axis S2. For example, leg springs through which the bearing shaft 76 passes and which are located on the one hand on bearing blocks 79A and on the other hand on the support bearing section, for example, would be possible Support 78. Elastic positioning springs 71A, 72A in the form of, for example, rubber buffers are also schematically shown, which are supported outside of the bearing 15 on fixed structures on the one hand of the joint arrangement 13, for example the support bearing section 78, on the other hand of the machining head 11, for example the support body 16, and thus a positioning of the machining head 11 cause the handle element 12 with respect to the pivot axis S2.

The drive motor 100 is arranged eccentrically with respect to the articulation region 46 or with respect to the axis of rotation D of the tool holder 19. The transmission 80 is provided for power transmission between an output 81 of the drive motor 100. The transmission 80 comprises, for example, an arrangement of a plurality of gearwheels which bring about a change in speed, in particular a speed reduction, and / or a force deflection from the output 81 to the tool holder 19. A purely rotary transmission concept is provided here, i.e. the tool holder 19 rotates exclusively about the axis of rotation D. However, an eccentric movement eccentric to the axis of rotation D, for example, would also be possible, but this is not shown in the drawing and would represent a different embodiment. Furthermore, a rotational movement of the tool holder 19 with a superimposed eccentric movement would also be easily possible, for example if a suitable transmission gear were present instead of or in addition to the gear 80. Finally, a so-called hypercycloid movement mode of the tool holder 19 is also possible by means of a corresponding gear.

The output 81 meshes with a gear wheel 82 which drives a shaft 84 to which the gear wheel 82 is connected in a rotationally fixed manner. Furthermore, a gear 83 is connected to the shaft 84 in a rotationally fixed manner, which in turn meshes with an output gear 85. The output gear 85 is arranged non-rotatably on a shaft 86, on the free end region of which the tool holder 19 is arranged non-rotatably.

The arrangement of the gears 82, 83, 85 causes a reduction in speed and also a deflection of the force, since the axis of rotation of the output 81 and the shaft 86 are not coaxial.

The shaft 84 is rotatably supported by bearings 87 on the one hand with respect to the carrier body 16 and on the other hand with respect to a gear housing 90 connected to the carrier body 16. The carrier body 16 forms a cover for the gear housing 90. For example, bearing receptacles 91 are provided on the carrier body 16 and the gear housing 90 for the bearings 87, which are designed in particular as roller bearings, preferably ball bearings.

The shaft 86 is rotatably supported with respect to the bearing housing 90 via a further bearing 87 with respect to the carrier body 16 and a bearing 88, which is received in a bearing receptacle 92 of the bearing housing 90. The respective longitudinal end regions of the shafts 86, 84 are thus supported by rotary bearings on a protective housing.

The gear housing 90 has a plate 96 on which the bearing receptacles 91, 92 are provided. The bearing receptacle 92 is provided on its underside facing the tool receptacle 19 with a sealing edge 93 surrounding the bearing receptacle 92, so that the gear housing 90 tightly encapsulates the gear 80 from below. The bearing 88 rests against the sealing edge 93 with, for example, an additional seal in a dust-tight manner.

The top-side encapsulation of the gear 80 is expediently implemented by the support body 16. The support body 16 has plug-in receptacles, not visible in the drawing, for example, into which plug-in projections or screw domes 95 of the gear housing 90 engage from below. An edge area 97 of the gear housing 90 is provided with a seal, for example, so that it rests tightly against a sealing area 98, for example a sealing edge, of the support body 16.

The support body 16 thus contributes to the encapsulation of the transmission 80. Towards the top, it seals the transmission housing 80 almost completely, apart from one Motor mount 89, in which the drive motor 100 is received. The support body 16 forms, for example, a housing part of the gear housing 80, in particular a housing shell.

In front of the support body 16, support projections 99, for example arms, protrude laterally, for example four support projections 99, on each of which bolt receptacles or assembly receptacles 94 for receiving assembly elements 94B for connection to the cover 21 protrude.

The suction connection 23 is also provided on the gear housing 90. The suction connection 23 projects laterally in front of the support body 16.

The drive motor 100, like the gear 80, is optimally protected against dust, which will become clear below. The drive motor 100 has, for example, a rotor 101 that is received in a stator 110. The drive motor 100 is a brushless, electronically commutated motor which can be energized by the energizing device 40.

The rotor 101 comprises a motor shaft 102 on which a laminated core 103 is arranged. Longitudinal ends of the motor shaft 102 protruding in front of the laminated core 103 are rotatably supported with respect to the stator 110 with a motor bearing 104 and an output bearing 105, for example roller bearings and / or slide bearings.

A fan holder 108 for holding a fan wheel 109 is provided at a free end region of the motor shaft 102, for example at the motor bearing 104.

A fan wheel 109 and the tool holder 19 are arranged on opposite sides of the drive motor 100.

The fan wheel 109 realizes a pressure ventilation, ie air is sucked in through the inflow opening 25 by the fan wheel 109, flows through the stator 110 and exits the stator 110 on the side of the stator 110 opposite to the fan wheel 109, in the area of the output bearing 105 and flows further to the air outlet area 18.

The stator 110 comprises a stator body 111 which, on a bearing cover 125A, has a bearing receptacle 112 in which the motor bearing 104 is received. The motor shaft 102 penetrates, for example, a through opening 113 of the stator 110 and is held with one end region on the motor bearing 104. The bearing cover 125A is, for example, in one piece with the stator body 111, but could also be designed as a component detachably connected to the stator body 111, like the bearing cover 125 explained later.

In addition to the passage opening 113, a projection 114 is provided which engages in a groove 106 on the rotor 101, for example on the laminated core 103. This creates a certain labyrinth structure which contributes to the tightness of the drive motor 100. The laminated core 103 is received in a rotor receptacle 115 of the stator body 111.

The stator body 111 is made of a plastic material, for example. Coils 121 of an excitation coil arrangement 120 are arranged on carriers 116 of stator body 111. A circumferential wall 117, for example made of plastic material, of the stator 110 extends radially on the outside of the carriers 116.

A base of the carrier 116 is formed, for example, from the material of a laminated core 111B, which is overmolded with the plastic material to form the stator body 111.

The excitation coil arrangement 120 has connections 122, 123 and 124, which are electrically connected to the conductors L1, L2, L3. The connections 122-124 are assigned to phases P1, P2 and P3 of the excitation coil arrangement 120. The connections 122-124 are arranged, for example, on an end face of the stator body 111, in particular the circumferential wall 117.

The rotor receptacle 115 is closed by a bearing cover 125 which can be integrated into the motor housing 24. The bearing cover 125 has, for example, a bottom wall 133 from which a closure projection 126 for closing the rotor receptacle 115 protrudes. The closure projection 126 has a projection 127 which is inserted into a groove 107 of the rotor 101, namely on the Laminated core 103, engages. As a result, a labyrinth-like seal or labyrinth seals 118 are implemented. The projections 114, 127 are, for example, annular projections, while the grooves 106, 107 are annular grooves. The grooves 106, 107 are provided, for example, on opposite end faces of the laminated core 103.

The bottom wall 133 and the closure projection 126 seal the drive motor 100 on its end face at the motor mount 105. A wall 17 of the gear housing 80, which can, for example, be a component of the support body 16, also forms a wall that closes the drive motor 100 at the end.

In the area of the closure projection 126, a receptacle 128 for a bearing receiving element 130 is also arranged. The bearing receiving element 130 has a bearing receiving 131 for the output bearing 105. The bearing receiving element 130 is screwed into a thread 129 of the receptacle 128, for example, or is locked with corresponding latching contours in the receptacle 128. A sealing washer 132 or some other sealing element is also held in the bearing receiving element 130. The sealing washer 132 holds the output bearing 105 in the bearing receptacle 131.

Cooling channels 119 are provided between the carriers 116 of the stator body 111 and thus between the coils 121, through which the cooling air K can flow through the stator 110 and thus the excitation coil arrangement 120. The cooling air K flows into the cooling channels 119 on a side of the drive motor 100 facing away from the tool holder 19 and out of the cooling channels 119 on the side of the drive motor 100 facing the tool holder 19. There it is deflected radially outward by a bottom wall 133 of the bearing cover 125 and flows through a flow space 134 to a peripheral wall 135 of the cover 130, on which the air outlet region 18 is provided. For example, ribs 136 are provided on the circumferential wall 135, between which there are spaces or outflow openings 137 through which the cooling air K can flow out of the motor housing 24. The flow space 134 is provided between the peripheral wall 135 and the peripheral wall 117. Between the perimeter wall 117 and the peripheral wall 135 advantageously extend support ribs or support walls 138. Conductor mountings 139 for receiving or holding the lines L1, L2 and L3 are advantageously provided on the support walls 138.

The cable 42 is introduced into the flow space 134 via an inlet 140 on the peripheral wall 135. The individual lines L1, L2 and L3 are led out of the cable 42 and held on the support walls 138, namely the conductor receptacles 139, and connected to the connections 122-124 of the excitation coil arrangement 120.

In Figure 11 it becomes clear that the bottom wall 133 runs above the carrier body 16 and the peripheral wall 135 protrudes, so to speak, in front of the carrier body 16. The circumferential wall 135 is provided on its upper end 141 with a sealing contour 142 which engages with a corresponding sealing contour 143 of a circumferential wall 144 of the motor housing 24. This results in a substantially dust-tight connection between the motor housing 24 and the bearing cover 125.

A flow housing or air guiding body 145, which extends around the drive motor 100, is received in the motor housing 24. For example, the air guiding body 145 has a wall 146 which delimits an air guiding area 147 around the drive motor 100. The wall 146 is designed, for example, as a type of air guiding sleeve and / or peripheral wall and / or as a flow housing. In any case, the cooling air K flows through the air guiding region 147, which can also have channels, along the outer circumference of the stator 110 and cools it. The wall 146 is cylindrical, for example, in the area of the fan wheel 109 and protrudes up to the fan wheel 109.

The wall 146 thus contributes to the fact that fan blades 109A of the fan wheel 109 press the cooling air K particularly effectively towards the drive motor 100 or the stator 110 and the rotor 101, so to speak.

The air guiding body 145 extends radially at its longitudinal end region remote from the fan wheel 109 (with respect to a longitudinal axis of the motor shaft 102) End wall sections 146A and 146B which extend outwardly from wall 146 with respect to motor shaft 102 and which run above air outlet region 18 and thus direct the cooling air K radially outward from motor housing 24.

It is preferably provided that the drive motor 100 is electromagnetically shielded. For example, the air guiding body 145 can be designed as an electromagnetically shielding housing. For this purpose, the air guiding body 145 consists, for example, of metal or has a metallic component. However, in an advantageous embodiment of the invention, the motor housing 24 can also be electromagnetically shielding, for example provided with an electrically conductive protective film or protective layer.

The lines L1-L3 in the cable 42 are advantageously guided in an electromagnetic shield 177, in particular a braid. Shield 177 is preferably grounded. A total of ten contributes to the electromagnetic compatibility of the drive motor 100 and the hand machine tool if the shield 177 is conductively connected to the drive motor 100, for example to the stator 110, in particular the laminated core 111B. The shield 177 can be applied to this in a conductive manner, for example by means of a spring.

The motor housing 24 has a protruding wall 148 and a top wall 149 in the region of the air inlet or the inflow opening 25. The top wall 149 covers, so to speak, the motor housing 24 at the top, but air passages or air inlets 150 for the cooling air K are present on the top wall 149.

In the area of the top wall 149, a receptacle 151 is provided for a filter element 152, which is inserted into the receptacle 151. For example, the receptacle 151 is delimited by the inner circumference of the projection wall 148. The filter element 152 has, for example, a filter fabric 154 or some other close-meshed filter structure which is arranged above the air inlets 150. Thus, dirt, for example dust or the like, which is contained in the cooling air K, is filtered by the filter element 152.

The filter element 152 is expediently latched on the motor housing 24 by means of latching means 153, for example comprising a resilient latch or the like. The latching means 153 form components of a holder 153A.

A receptacle 155 for a protective body 156 is provided on an upper, free end region of the motor housing 24. While the motor housing 24 consists of a relatively hard plastic so that it can develop an optimal protective effect for the drive motor 100, the protective body 156 is comparatively flexible or elastic. The protective body 156 is designed, for example, in the manner of a clasp. The protective body 156 optimally cushions impacts which can act on the machining head 11 and thus in principle would damage the drive motor 100.

It is preferred if the protective body 156 is flexible in bending. The protective body 156 is actually horseshoe-shaped or U-shaped, but it can be bent. It is thus possible, for example, to suspend holding receptacles 158 arranged at its free end regions in holding projections 159 of the motor housing 24, so to speak. It is advantageous if the protective body 156 also has further holding contours, for example a holding projection 158A, which runs along a side edge and can be hooked into a corresponding, for example U-shaped, holding receptacle 159A of the motor housing 24.

The drive motor 100 is provided with a protective circuit 160 which protects the drive motor 100 from overheating or other damage on site, namely on the machining head 11.

The protective circuit 160 has a circuit breaker 161, for example. In principle, it would be possible to integrate the isolating switch 161 directly into the motor housing or at least into the stator 110 of the drive motor 100. In the present case, however, an assembly-friendly, easily retrofittable or exchangeable concept is selected in which the disconnector 161 is arranged outside the stator 110, but in direct contact with it.

The isolating switch 161 comprises or is formed by a thermally actuable switch, the thermally actuable switch moving into a disconnected position when the stator 110 is heated above a predetermined temperature, but otherwise assumes a connecting position. In the connected position, the isolating switch 161 connects the conductor L1 to the connection 122 assigned to a phase of the excitation coil arrangement 120, while in the disconnected position it disconnects the conductor L1 from the connection 122 and thus the phase P1 of the excitation coil arrangement 120.

The circuit breaker 161 is expediently arranged in a protective housing 162 which has a housing part 163A and a housing part 163B. The protective housing 162 expediently completely houses the circuit breaker 161. It would be possible that as in Figure 13 shown the protective housing 162 is open at its top, so that air can reach the circuit breaker 161. However, the protective housing 163 is preferably completely closed, so that the isolating switch 161 can react particularly sensitively and quickly to temperature changes, in particular excessively high temperatures.

The protective housing 162 delimits, for example, a receptacle 164, for example a chamber, in which the isolating switch 161 is arranged. The housing parts 163A, 163B are latched to one another, for example, for which purpose latching contours 165 are provided.

The housing part 163B forms a thermal insulator which protects the circuit breaker 161 from the influence of heat from the outside on the drive motor 100, so that the circuit breaker 161 is not incorrectly actuated by such heat influence.

The housing part 163A, on the other hand, is thermally conductive, so that heat coming from the stator 110 can actuate the isolating switch 161. It is an advantageous measure if a heat-conducting element 169 is also arranged, for example a so-called heat-conducting pad, which conducts the heat from the stator 110 in the direction of the protective housing 162 and thus to the isolating switch 161.

The heat-conducting element 169 preferably has a geometry and surface area which corresponds to the geometry and surface area of an end face of the protective housing 162 facing the stator 110.

The heat-conducting element 169 also compensates for unevenness in the protective housing 162 and / or the stator 110, which advantageously improves the heat transfer from the stator 110 to the isolating switch 161.

Another advantageous measure provides that a spring 168, that is to say a spring arrangement, is provided to load the isolating switch 161 in the direction of the stator 110. The spring 168 is arranged, for example, on the housing part 163B, in particular its front wall.

On the side of the protective housing 162, conductor passages 166 are provided for a subsection L1A of the conductor L1 and a conductor section L1B connected to the connection 122.

The isolating switch 161 advantageously has a housing 161B which encapsulates it and in which its electromechanical components, in particular a bimetal strip 161C, electrical contacts and the like, are housed in an electrically insulated manner. The housing 161B is preferably dustproof. The housing 161B has, for example, electrical contacts for connecting the conductor sections L1A and L1B. When exposed to heat or cold, the bimetal strip 161C moves between the in Figure 10 schematically drawn positions back and forth, where he establishes an electrical connection or disconnects.

When the disconnector 161 moves into its disconnected position, no more current flows via the lines L1. The current monitoring device 171 of the current supply device 40 can determine this and report it to the controller 170. The controller 170 then switches the energizing device 40 as a whole in such a way that no more current flows via the lines L1-L3. The controller 170 thus detects a fault in the drive motor 100 in a decentralized manner, so to speak. There, only the isolating switch 161 is required as a safety measure. On this one This saves data transmission lines, for example, which would otherwise have to be routed from the machining head 11 via the handle element 12 to the controller 140. The controller 170 preferably works without a sensor, ie without any rotation angle information coming from the drive motor 100 from a rotation angle sensor arranged there.

Of course, it is fundamentally possible that, for example, a rotation angle sensor 174 is arranged on the drive motor 100, which detects the respective rotation angle position or speed of the rotor 101 and transmits it via a data line 176, which preferably runs in the handle element 12 (in Figure 13 indicated schematically), reports to the controller 170. In this way it is also possible for the controller 170 to evaluate a respective rotational angle position of the rotor 101 and to energize the excitation coil arrangement 120 on the basis of this at least one rotational angle information.

It goes without saying that other or further isolating switches in the drive motor 100 can also be advantageous, for example a current switch 175 which detects a current flow on the line L2 and which, when the current flow is above a predetermined current value, the line L2 from the phase P2 separates. It would be readily possible for the current switch 175 to be arranged in series with the isolating switch 161, for example on the line L1.

The handle bar or the handle element 12 is in accordance with the exemplary embodiment Figures 1-15 in one piece, that is, for example, even the channel bodies 33, 36 can be components of an overall continuous tubular body.

However, a multi-part handle element is also readily possible, which is based on the Figures 16-18 becomes clear. For example, instead of the channel body 33, a two-part channel body 233 can be provided. The channel body 233 has segments 234, 235, for example. The segments 234, 235 can be detached from one another, for example ( Figure 16 ).

The flow channel 34 runs in the segments 234, 235.

For example, the cable 42 is led out of the channel body 233 at an end region 236 of the segment 35.

The cable 42 comprises the lines L1-L3, i.e. a total of three current-carrying lines which lead along the channel body 233 to the energization device 40 and can be detachably connected to one another at the separation point between the segments 234 and 235.

The segments 234, 235 can be detachably connected to one another, so that they are separated from the in Figure 16 shown separated position in a in Figure 17 shown interconnected position can be brought. A connection device 240 is used to releasably connect the segments 234, 235. A continuous flow channel 34 is then implemented. The flow channel 34 runs through the plug-in projection 241 and the plug-in receptacle 242.

Alternatively or in addition, a plug connection is also possible, i.e. that, for example, the connecting projection 241 has a plug-in projection and the connecting projection 242 has a plug-in receptacle, which can be plugged into one another.

The connecting device 240 further comprises holding means in the form of holders 243 movably mounted on segment 234, which can be brought into engagement with holding receptacles or holding projections 244 on segment 235. The holders 243 are pivotably mounted, for example, on bearings 245, so that they can be pivoted away from the holding projections 244 and thus out of engagement therewith.

It is preferred if the holding projections 244 can engage in recesses or other holding receptacles on the segment 234. An additional form fit between the segments 234, 235 is thus implemented.

Electrical contact arrangements 250, 260, which can be detachably connected to one another, are used for the electrical connection between the segments 234, 235. The contact arrangement 250 comprises, for example, contacts 251, 252, 253 which are assigned to the conductors L1-L3 and are connected to them. For example, the contacts 251-253 are arranged on a contact carrier 254, in particular in depressions or otherwise mechanically protected. The contact carrier 254 is configured, for example, in the manner of a projection or in the form of a comb.

The contact arrangement 260 comprises corresponding contacts 261-263, which are also assigned to the lines or conductors L1-L3. The contact arrangement 260 is arranged on a contact carrier 264, which is pivotably mounted on the segment 234 by means of a pivot bearing 265. For example, the contact carrier 264 is integral with the holder 243 of the segment 234 or is coupled in terms of movement. Thus, contacts 261-263 can be pivoted away from contacts 251-254 for electrical isolation or for electrical connection to them.

A holding receptacle 266 on the contact carrier 264 can be brought into engagement with a holding projection 256 on the segment 235 to additionally secure this connection between the segments 234, 235 or the contacts 261-263 with the contacts 251-254.

The connection between the segments 234 and 235 can be secured by additional latching means, screwing means or the like.

One recognizes in this connection the advantage of the safety concept with the protective circuit 160 and the isolating switch 161, because namely the contact arrangements 250 and 260 only require a total of 3 contact pairs, namely for the lines L1, L2 and L3.

According to a concept that is advantageous not only in the specific exemplary embodiment, it is provided that an inflow opening for a cooling air flow and a machining side BS having a tool holder (19 in the present case) are arranged on opposite sides, in particular end faces, of a motor housing (here 25) or a machine housing.

An outflow direction for the cooling air flow K expediently runs transversely to the processing plane E.

Claims (15)

1. Hand-operated power tool, in particular grinder, with an in particular rod-shaped handle element (12) for grasping by an operator and with a machining head (11), which is movably mounted at the handle element (12) via a joint assembly (13) and which has a tool holder (19) drivable by an electric drive motor (100) - located at the machining head (11) in particular - of the hand-operated power tool (10), wherein a line assembly (41) is provided between the handle element (12) and the machining head (11) for transmitting electric and/or mechanical energy and/or for passing a suction flow (S), wherein the machining head (11) is loaded towards a predetermined basis position relative to the handle element (12) by a positioning spring assembly (70) separate from the line assembly (41), characterised in that the positioning spring assembly (70) comprises at least one positioning spring (71, 72), which is directly supported at bearing elements (64, 68) of the joint assembly (13).
2. Hand-operated power tool (10) according to claim 1, characterised in that the joint assembly (13) comprises or is represented by a sliding bearing for the linear adjustment of the machining head (11) relative to the handle element (12) and/or a swivel bearing assembly (14, 15), wherein the machining head (11) is mounted pivotably about at least one pivot axis relative to the handle element (12) by means of the swivel bearing assembly (14, 15).
3. Hand-operated power tool according to claim 2, characterised in that the swivel bearing assembly (14, 15) comprises, for in particular gimballed mounting, a first swivel bearing (14, 15) for pivoting the machining head (11) relative to the handle element (12) about a first pivot axis and a second swivel bearing (14, 15) for pivoting the machining head (11) relative to the handle element (12) about a second pivot axis, the first and the second pivot axes being oriented at an angle, in particular a right angle, to each other.
4. Hand-operated power tool according to any of the preceding claims, characterised in that at least one positioning spring (71, 72) of the positioning spring assembly (70) is assigned to at least two and preferably to each of the degrees of freedom of movement of the machining head (11) relative to the handle element (12), and/or in that the machining head (11) is mounted movably relative to the handle element (12) by at least one degree of freedom of movement not affected by the positioning spring assembly (70), and/or in that the machining head (11) is mounted movably relative to the handle element (12) about two pivot axes oriented at an angle, in particular a right angle, to each other, wherein the positioning spring assembly (70) loads the machining head (11) towards the basis position only with respect to one of the two pivot axes, in particular only with respect to a pivot axis extending transversely to a longitudinal axis of the handle element (12).
5. Hand-operated power tool according to any of the preceding claims, characterised in that the positioning spring assembly (70) comprises a leg spring and/or an elastic rubber buffer and/or an elastic plastic buffer and/or a coil spring through which at least one pivot axis (S1, S2) of the joint assembly (13) passes in particular.
6. Hand-operated power tool according to any of the preceding claims, characterised in that the positioning spring assembly (70) comprises a first positioning spring (71) and a second positioning spring (72), which apply pressure to the machining head (11) towards the basis position in opposite directions and/or from opposite sides and/or with opposite direction of rotation.
7. Hand-operated power tool according to any of the preceding claims, characterised in that the positioning spring assembly (70) comprises at least one additional positioning spring (71A, 72A) supported between a longitudinal end of the handle element (12), in particular at a distance from the longitudinal end of the handle element (12), and the machining head (11).
8. Hand-operated power tool according to any of the preceding claims, characterised in that at least one positioning spring (71, 72) of the positioning spring assembly (70) is located at an inner circumference or an outer circumference of a bearing shaft part, in particular a bearing pin, or passed through by the bearing shaft part or extends in an annular fashion around at least one pivot axis (S1, S2) of the joint assembly (13).
9. Hand-operated power tool according to any of the preceding claims, characterised in that at least one positioning spring (71, 72) of the positioning spring assembly (70) is at least partially or completely accommodated in a housing, in particular a bearing housing of a bearing element of the joint assembly (13).
10. Hand-operated power tool according to any of the preceding claims, characterised in that the joint assembly (13) comprises a fork (50) projecting from the handle element (12), wherein the machining head (11) or a bearing element joined to the machining head (11) in a fixed or articulated manner is held or located between fork arms (51, 52) of the fork (50), wherein it is expediently provided that the positioning spring assembly (70) is supported, in particular exclusively, on the fork (50), in particular on the fork arms (51, 52), with respect to the handle element (12).
11. Hand-operated power tool according to any of the preceding claims, characterised in that, in the basis position, a longitudinal axis of the handle element (12) on the one hand and an axis of rotation of the tool holder (19) and/or a machining plane (E) of the machining tool (20) provided for machining a workpiece (W) on the other hand extend relative to each other at an angle between 0° and 90°, in particular at an angle between 20 and 70°, preferably at an angle of 30-60° and particularly preferably in a range of 25-40°, in particular approximately 30°.
12. Hand-operated power tool according to any of the preceding claims, characterised in that the positioning spring assembly (70) counteracts a spring action of the line assembly (41) for moving the machining head (11) into the basis position and/or compensates for the spring action of the line assembly (41), and/or in that the positioning spring assembly (70) and the line assembly (41) together load the machining head (11) towards the basis position, and/or in that a spring action or spring constant of the positioning spring assembly (70) is greater than a spring constant of the line assembly (41), and/or in that the positioning spring assembly (70) compensates for a weight load - eccentric with respect to a pivot axis (S1, S2) - of the machining head (11), applied by the drive motor (100) in particular.
13. Hand-operated power tool according to any of the preceding claims, characterised in that at least one pivot axis, preferably two pivot axes or all pivot axes, of the joint assembly (13) extend(s) through a centre of gravity region or a middle region or a centre of the machining head (11).
14. Hand-operated power tool according to any of the preceding claims, characterised in that the joint assembly (13) has a first pivot axis and a second pivot axis oriented at an angle, in particular a right angle, to each other, wherein it is advantageously provided that the first pivot axis extends transversely, in particular at right angles, to a longitudinal axis of the handle element (12) and the second pivot axis and the longitudinal axis of the handle element (12) are located in a common plane or in planes that are parallel to each other.
15. Hand-operated power tool according to claim 14, characterised in that the position spring assembly (70) loads the machining head (11) towards the basis position with respect to the first pivot axis, in particular exclusively with respect to the first pivot axis.

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