EP2563540A1

EP2563540A1 - Hacksaw

Info

Publication number: EP2563540A1
Application number: EP11713297A
Authority: EP
Inventors: Jochen Roser; Hans Kaiser; Aldo Di Nicolantonio; Stefano Delfini; Martin Fischer; Hans-Peter Grabsch; Ulli Hoffmann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-04-27
Filing date: 2011-04-11
Publication date: 2013-03-06
Also published as: DE102010028233A1; WO2011134775A1

Abstract

The invention relates to a hacksaw or jigsaw (10) comprising at least one housing (14), a tool area (16) for a linear and/or oscillating driven saw blade (18), a control (20) on the housing side for activating a working saw motion (24) by an operator, a drive unit (22) disposed in the housing (14) for generating the working saw motion (24) of the saw blade (18), an electronic unit (36) disposed in the housing (14) for applying at least control and/or feedback signals to the drive unit (22). The drive unit (22) comprises at least one excitation actuator (38) having a volume of active excitation material for generating a microwork motion (28) controlled or regulated by the electronic unit (36) during operation. According to the invention, the excitation actuator (38) can overlay the microwork motion (28) at least on the working saw motion (24) of the saw blade (18).

Description

description

title

Lift saw prior art

The invention relates to a lifting saw, in particular a stab, saber, or hacksaw, at least comprising a housing, a tool area for a linear and / or oscillating drivable saw blade, a housing-side control panel for user-side activation of a sawing movement, one in the housing arranged drive unit for generating the Sägearbeitsbewegung of the saw blade, an electronics unit arranged in the housing for applying the drive unit with at least control and / or control signals, wherein the drive unit comprises at least one excitation actuator with a volume of excitation active material for generating a micro-working movement, which in the operation of the electronic unit is controlled or regulated.

Lifting saws are sawing tools, in particular hand-held electric saw tools that enable a sawing operation by means of an oscillating movement of a one-sided or bilaterally clamped saw blade. Typical representatives of lifting saws are in particular stab, saber or hacksaws.

A hacksaw is a lifting saw machine that works with repeated, straight-line cutting action. During the return stroke (idle stroke), the saw blade, which is usually clamped on both sides, is raised to protect the saw blade. In general, a hacksaw includes a solid base with a chip tray on which a movable saw arm is attached. Left and right of the arm a saw blade is usually clamped in the saw bow by means of mounting holes. In operation, the saw moves forward and backward like a manual saw, usually with a hydraulic cylinder ensuring a steady contact pressure and a cyclic lowering of the arm. A jig saw is an electric hand-held lifting saw, with which various materials can be sawn by the lifting movement of a cantilevered saw blade. The saw blade can pierce with the free end in the material to be cut through, but this is usually a hole, such as a hole, necessary. Due to the small width of the saw blade, one can lead relatively tight curves and cut out curved lines of materials. In modern jigsaws, the saw blade back is supported by a roller and usually also precisely guided. This roller support is cyclically moved in pendulum stroke jigsaws in the saw advancing direction, so that the saw blade swings forward and backward, whereby sawdust can be ejected better. The sawing performance is significantly higher compared to a saw without pendulum stroke.

A saber saw is a hand-held hacksaw, which is used mainly by plumbers, carpenters and builders, and is also referred to as Recipro-, tiger saw or electric foxtail. The most common applications are disassembling old components and cutting pipes, which require less precise cutting than large saw blade length, so that large workpieces can be quickly separated. For the separation of metal pipes, there are special guiding devices, which facilitates a straight cut. Saber saws are available in mains or battery-operated versions, whereby the saw stroke can be between 20 and 35 mm. Depending on the selection of the saw blade, different materials such as metals, wood, plastic, green waste, ceramics can be cut. The drive is usually done by an electric motor, which drives an eccentric with an eccentric with connecting rod to produce a saw blade stroke.

All of the aforementioned Hubsägearten subject in a drive by means of a single Sägearbeitsbewegung the problem of low Sägefortschritts and the risk of edge tears and unclean saw cuts.

Disclosure of the invention

The invention relates to a lifting saw, in particular a stab, saber, or hacksaw, at least comprising a housing, a tool area for a linear and / or oscillating drivable saw blade, a housing-side control panel for user-side activation of a sawing movement, one in the housing arranged drive unit for generating the sawing movement of the saw blade, an electronics unit arranged in the housing for applying at least control and / or regulating signals to the drive unit, wherein the drive unit comprises at least one excitation actuator with a volume of excitation-active material for generating a micro-working movement, which in operation of the Electronic unit is controlled or regulated.

It is proposed that the excitation actuator can superimpose the micro-working movement at least on the sawing movement of the saw blade. Thus, the Sägewerk- beitsbewegung is superimposed on a micro-working movement, and imprinted on the saw blade overlay vibrations in the form of micro-working movements. The drive unit comprises as another drive component for generating the sawing movement, for example, an electric drive motor, which in a housing of Hubbzw. Stick saw is included. The motor shaft is usually coupled via a gear unit with a lifting shaft, which is the carrier of the saw blade or of the saw arm and carries out the sawing movement. The saw blade is usually replaceable attached to the lifting shaft or on the saw arm.

If the excitation actuator is operated with its resonant frequency for generating the micromachine movement, a high mechanical output power for generating the micromachining movement can be delivered if the quality of the oscillatory system is sufficiently high in accordance with an electrical input power. The excitation actuator may be an ultrasonic excitation actuator, in particular a piezoelectric actuator in the construction of a Langevin transducer. The piezoelectric actuator has piezoelectric material as excitation-active material. Typically, the goodness of the undamped lies

The resonant system of the excitation actuator, which has the resonant frequency, comprises the Langevin oscillator with piezoelectrically active material and components coupled to the vibrator, in particular components that amplify the ultrasound and / or transmit it to a processing location. Such components are e.g. as a booster or

Sonotrode known. This enables a size reduction and the provision of a compact device. Advantageously, a compact jigsaw high performance is thus created, which is handy at the same time. Due to the superposition of the micro-working movement on the sawing movement of the tool on the one hand and the usually much higher frequency remains generating the overlay vibrations without influence on the sawing movement and thus on the Result of sawing. In addition, the overlay vibrations usually have only a very small amplitude, so that the sawing of the workpiece is not impaired. However, the superposition of the micro-working movement on the sawing movement allows an improved cutting result, a reduction of frictional forces and thus a longer life of the saw blade and a lower power requirement of the conventional drive motor, a faster Sägefortschritt, a reduction of the resulting chips, generation of clean cut edges and a tear-free sawing and thus a much calmer and more accurate sawing.

In principle, the one excitation actuator of the drive unit can generate both the sawing movement and the micro-working movement. According to a favorable development of the invention, the drive unit may have, in addition to the at least one excitation actuator, at least one further drive component, in particular a drive motor, preferably an electric motor for generating the sawing work movement, in particular a lifting or jigsaw working movement and / or a pendulum and / or free-cutting movement include. Thus, multiple excitation actuators, e.g. be provided with the same or different resonant frequency, as drive components or a combination of one or more oscillating excitation actuators with a conventional electric motor. To generate the sawing work movement, a drive motor is generally used, it being possible to advantageously combine one or more oscillating and micromachining motion-producing excitation actuators for this purpose. The various drive components can be operated alternatively or in combination, and in particular saw blade movements in different directions, in particular in sawing direction, in

Create saw progress direction and / or in a direction orthogonal cut-free direction. The superposition vibrations, which do not originate from a drive motor, but from the excitation actuator, can be generated with a frequency that leads to a significant reduction of the chip size. For example, a jigsaw motor usually produces a sawing movement in a frequency range of 5 to 250 Hz, this can be superimposed micro-working movements in a frequency range from 20 to 100kHz, which serve to break chips, perform micropipetal movements, perform microfreaking movements, etc. Da smaller chips have a smaller heat capacity, the chips can cool down in a shorter period of time, whereby the risk of fire is reduced. In addition, lead smaller chips at a reduced risk of injury, since the pulse emanating from them is less.

In a further development of the preceding embodiment, the micro-working movement can be switched on independently of the sawing movement. Thus, the at least one excitation actuator can be activated separately from the at least one further drive component, in particular the drive motor. In this way, if necessary, the micro-working movement of the sawing work movement can be superimposed. It is also conceivable that the sawing movement can be switched off, and only the micro-working movement is activated, for. B. in the case of a stuck saw blade, which can be done with the help of micro-working movement a free cutting. Furthermore, in the case of exact saw cuts and advantageously at critical points or at the beginning or end of saw cut areas, sawing can be carried out only by means of a micromachining movement. It is also conceivable, in the case of several micro-working directions of movement, if necessary, to activate only one micropositioning movement, one microfibrillating movement or only one micro-working movement acting in the sawing direction or to superimpose the sawing work movement in order to achieve an advantageous sawing result.

According to a favorable development of the invention, the micro-working movement can excite or overlay the sawing movement of the saw blade in at least one of the following directions:

in the direction of the sawing movement, in particular the jigsaw movement and / or;

orthogonal to the sawing movement of the saw blade as a longitudinal movement in the direction of the saw progress and / or;

orthogonal to the sawing movement of the saw blade as a cross-pendulum or free-cutting movement in the transverse direction to Sägefortschritt. This can be done, for example, by the drive unit comprising, in addition to a saw excitation actuator, at least one or more excitation actuators for generating micromachining movements, the micromachining movements being directed in the direction of the sawing work movement or orthogonally superimposed thereon, for example, in saw progress or in a clearing direction. In this case, a combination of these directions of movement is conceivable, with the necessary micro-working movements being generated by individual excitation actuators or by a common excitation actuator can. As a result, the work progress can be significantly improved, relieved the Sägeanregungsaktor, the saw blade spared and editing can be facilitated. The selective use of a micro-working movement in a sawing, sawing, or cross-cutting device with or without superimposed sawing movement can advantageously be combined, for example:

- be superimposed directly on the sawing motion, with or without conventional pendulum motion;

- be used instead of the lifting movement in particular for the separation of flexible materials such as fabrics, carpets, rubber, leather, foams;

- act on the saw blade with or without Sägearbeitsbewegung instead of the pendulum motion in Sägefortschrittsrichtung;

- act across the cutting direction to achieve or improve a free cutting;

- represent a previous meaningful combination.

For this purpose, the stroke size and stroke frequency of the micro-working movement can be adjusted according to the type of saw blade and the purpose.

According to a favorable development of the invention, the excitation actuator can act on a bearing or a roller support of the lifting or jigsaw. As a result, the superimposed vibrations emanating from the excitation actuator act on a bearing or a roller support of a jigsaw, wherein the vibrations propagate to the saw blade via the bearing. The roller support can also serve to produce a pendulum movement or a free-cutting movement of the saw blade, for example in a pendulum jigsaw. In the case of several bearings, the saw blade drive is preferably carried out on the saw blade near bearing to a load of

Gear unit and the drive motor to avoid by the overlay vibrations. In particular, by stimulating the roller support of a jigsaw, a superimposed pendulum stroke movement and / or a free-cutting movement of the saw blade can be generated without great design effort.

According to a favorable development of the invention, the electronic unit can be designed to operate the at least one excitation actuator at a resonance frequency (f_res) and in particular comprise a control unit with frequency adaptation for tracking the resonance frequency (f_res) of the at least one excitation actuator. Advantageously, the resonance frequency during operation of the lifting or jigsaw be continuously adjusted if, for example due to temperature change, change of the coupled to the excitation actuator saw blade or load of the tool, the resonance frequency of the excitation actuator changes. Thus, an optimal power yield is always possible during operation. Advantageously, the electronic unit may comprise a phase locked loop, with which the resonance frequency can be excited with high accuracy. Thus, a phase shift between electric current and electric voltage supplied to the piezoelectric active material to excite the ultrasonic vibrations can be set and maintained at a fixed value, particularly 0 ° phase difference between the current and voltage signals, thereby achieving optimum power output can.

According to a favorable development of the invention, the excitation-active material of the excitation actuator may be piezoelectric or magnetostrictive. Thus, the excitation actuator can be designed, for example, as a Langevin oscillator with clamped piezoelements which change their extent by applying a voltage. By a correspondingly high-frequency voltage application, the piezoelectric element can expand and contract in the desired frequency of the superposition oscillations, wherein the excitation is coupled to a component in the power transmission chain between the drive unit or drive motor and saw blade so that the vibrations of the excitation propagate into the saw blade can. As already described above, the excitation is preferably carried out via a lifting bearing of the tool shaft, which carries the saw blade. According to a further embodiment, it is provided that the excitation actuator is designed as a magnetorestrictive excitation, which is particularly suitable for generating ultrasonic vibrations, wherein an external magnetic field generated by a magnetic coil excites a magnetostrictive material, in particular an iron / nickel / cobalt alloy to change the length.

According to a favorable development of the invention, the at least one excitation actuator on the tool tip can have a vibration amplitude of at least 5 μm, preferably up to 100 μm, in particular 15 μm. A correspondingly high oscillation amplitude is advantageous for a good power transfer to the workpiece and thus for a high sawing progress through the lifting or jigsaw. According to a favorable development of the invention, the operating frequency of the at least one excitation actuator can be in the range between 10 kHz and 1000 kHz, preferably between 20 kHz and 100 kHz, in particular between 35 kHz and 45 kHz. With increasing frequency decreases the size of the components and increases the mechanical load of the vibrating system, resulting in the selected frequency range advantageous proportions at high output and favorable weight of the power tool. The frequency of the micro-working movement is expediently in the ultrasound range, so that no noise pollution occurs. On the other hand, it has been found that vibrations of this magnitude are particularly effective in order to significantly reduce the size of the chips that arise during the machining of a workpiece. However, it may be appropriate to create micro-working movements that are in much larger orders of magnitude. In principle, vibrations up to the megahertz range come into consideration. In addition, it is also possible to generate micro-working movements with lower frequency.

According to a favorable development of the invention, one or more visual and / or audible and / or haptic operating points can be provided for an activated state of the at least one excitation actuator. The reliability of the power tool is increased because it is clearly visible when the excitation is activated and can deliver mechanical power.

According to a favorable development of the invention, the at least one drive unit, electronic unit and an operating voltage unit can be distributed in the housing so that a center of mass lies in the region of the grip area, so that an operator can handle the jigsaw safely and comfortably, thereby increasing safety and ease of use becomes.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

They show by way of example: Fig. 1 is a perspective view of an embodiment of a hand-held jigsaw with excitation actuator for a micro-working movement;

2 is a perspective view of an embodiment of a hacksaw with excitation actuator for a micro-working movement.

3 shows an enlarged section of the tool area of the jigsaw of FIG.

1 ;

Fig. 4 is an enlarged section of the saw arm of the hacksaw of Fig. 2;

Fig. 5 saw blade of a jigsaw in sawing motion with superimposed micro-working movement;

Fig. 6 saw blade of a jigsaw in pendulum motion with superimposed micro-working movement;

7 saw blade of a jigsaw in free-cutting movement with superimposed saw,

Pendulum and micro-labor movement;

Fig. 8 saw blade of a hacksaw with superimposed micro-working movements in

Sawing, lifting and cutting directions;

9 shows a schematic diagram of an electrical control of an excitation actuator of a lifting saw.

Embodiments of the invention

In the figures, the same or similar components are numbered with the same reference numerals.

To illustrate the invention, Figures 1 and 2 each show an example of a stitch or a hacksaw. Fig. 1 shows a hand-held jigsaw 10 with replaceable blade 18, which is preferably used on construction sites by craftsmen. Fig. 2 shows a stationary hacksaw, as can be found in wood processing companies. The concept of micro-working movement overlay is the same for all types of reciprocating saw, so that in this regard what is said for one embodiment also applies to the other embodiment.

The hand-held jigsaw 10 includes a housing 14 having a handle portion 78. An operator holds the jigsaw 10 against the handle portion 78 and can guide the jigsaw 10. The grip area 78 may optionally be decoupled with a damping element, not shown, with respect to other housing areas. The jigsaw 10 further includes a tool portion 16 for an oscillating drivable saw blade 18, about a wood or a metal saw blade according to the material to be machined. A control unit 20 on the housing side serves to activate the saw blade 18 on the user side. The control unit 20 can, for example, be a switch or a controller or also comprise a plurality of operating elements, one of which for activating a sawing movement 24, for controlling the frequency of the sawing work movement 24 and one for activating and / or regulating the frequency of a micro-working movement 28 may be provided.

In the housing 14, a drive unit 22 with excitation actuator 38 is arranged next to an electric motor for generating a Sägearbeitsbewe- 24 (shown in FIG.

6) that can generate a micro-motion 28. This can be designed as a piezo-excited Langevin oscillator (also called a piezoactuator) comprising a volume of piezoelectrically active material 40, e.g. Piezoceramic discs which are pressed together and undergo a change in length when subjected to electrical voltage. Beaocking with high-frequency electrical

Voltage is generated in a conventional manner ultrasound, which, as shown in Fig. 6, is passed via a coupling element 72 to the saw blade 18. The coupling element 72 may be a per se known sonotrode 74. The length and the shape as well as the material of the coupling element 72 determine a resonant frequency of the excitation actuator 38. The saw blade 18 can also influence the resonant frequency.

6, the excitation actuator 38 is designed so that Langevin oscillator 40 and coupling element 72 are combined in one unit, and their entire length corresponds approximately to half the wavelength λ / 2 of the ultrasonic oscillation. Other embodiments may provide that the excitation factor 38 is composed of several components with the length λ / 2. These may be: vibrators, known as converters, in particular, e.g. a Langevin oscillator, amplitude transformation pieces known as booster 72, possibly extension pieces, as well as the coupling element 74 known as sonotrode. FIG. 3 shows an enlargement of the tool area 16 of that shown in FIG

Jigsaw 10 is. The saw blade 18 is supported by a roller support 52 for reducing friction and for dissipating mechanical forces. The roller support 52 may be cyclically moved in the saw advancing direction 32 to produce a reciprocating movement of the saw blade 52, and the roller support 52 may be moved laterally to assist in a free cutting motion 48 of the saw blade 18. In the tool area 16, all three movements, the sawing work 24, the pendulum movement 46 and the free-cutting movement 48 are superimposed by micro-working movements 28 of the one excitation actuator 38 or of several excitation actuators 38 which can be operated independently of one another. The activation of the saw blade 18 by the operating part 20 can be visually, acoustically or haptically (by means of vibration) displayed with an operating display 56. In principle, it is also possible to position the one or another exciter actuator 38 at any desired location, for example at a tool-remote bearing or at the roller support 52 of the jigsaw, in order to apply this directly to superposition oscillations.

The hacksaw in Fig. 2 comprises a tool housing with drive unit 22, and a chip tray and a linear oscillating saw arm, in which a saw blade 18 is clamped. The saw arm moves upwardly during a movement of the saw blade 18 in a sawing direction 44, and in the saw direction opposite to the direction of sawing 44 in sawing progress direction 32 to perform a lifting movement 46. For this purpose, a micro-working movement of the lifting movement 46 and also the sawing work movement 44 can be superposed in order to improve the quality of cut and the service life of the saw blade 18. In order to reduce the size of the chips that are produced when machining a workpiece 76 with the saw blade 18, the saw blade 18 is acted upon in addition to the oscillating working movement, typically in a frequency range of 5 to 250 Hz with a micro-movement in the kHz range. Here, the saw blade 18 is superimposed in the direction of sawing 24 with a micro-working movement, and reciprocated with a pendulum motion 46 in Sägefortschrittsrichtung 32 oscillating. The pendulum movement 46, which is a lifting movement in the case of the hack saw of FIG. 2, can also be superimposed with a micro-working movement 28. These are overlapping vibrations that are superimposed on the working movement 24 of the saw blade 18. These superposition oscillations are generated by means of the excitation actuator 38, which is also arranged in the housing 10 of the hand-held power tool 10 in addition to the drive motor as a further drive component 50 of the drive unit and excites the saw blade 18 directly or indirectly to the superposition oscillations.

Fig. 4 illustrates an enlarged working range of the hacksaw of Fig. 2, in which only the hacksaw arm is shown with clamped saw blade 18. The office gelsägenarm is oscillated in sawing 30 moves. Further, upon movement of the saw blade 18 in sawing direction 30, a pendulum motion 46 upwardly or in the opposite saw direction 30 down in the direction Sägefortschrittsrichtung 32 to provide oscillating a lifting movement 46 to improve the sawing action. The sawing work movement 24, 44, the lifting movement 46 and a possible free cutting movement 48 orthogonal to the sawing 30 and Sägefortschrittsrichtung 32 can be superimposed by Mikroarbeitsbewegungen 28 one or more arranged in the housing 14 of the hacksaw 10 excitation actuators 38, with individual Mirkoarbeitsbewegungsrichtungen are selectively switched.

5 shows in sketch form the generation of a micro-working movement 28 in sawing direction 30 (FIG. 5 a), wherein an electromotive working movement 24 can be superimposed (FIG. 5 b). A saw blade 18 of a jigsaw 10 is excited in Fig. 5a with a micro-working movement 28, which is exerted by an excitation actuator 38, not shown, on a lifting shaft of the jigsaw 10, with a frequency of 40kHz.

The saw blade oscillates at high frequency in sawing direction 30 for sawing a workpiece, in particular thin flexible materials such as paper, leather, fabrics, foams, etc. can be separated. For this purpose, it is conceivable that instead of a conventional saw blade, a sharp cutting blade is inserted into the jigsaw, so that instead of a sawing a cutting process can be performed. According to Fig. 5b, the

Micro working movement 28 are superimposed by a conventional electric motor-generated sawing stroke 24 with a frequency in the range of 40Hz. In this case, the micro-working movement assists the progress of sawing in direction 32 and prevents jamming of the saw blade.

Fig. 6 shows a generation of a pendulum motion 46, as used in Pendelhub- jigsaws are used. In contrast to known reciprocating jigsaws, in which the roller support 52 is moved mechanically in the saw advancing direction 32 in tune with the lifting movement 24, in FIG. 6a an excitation actuator 38 comprising a piezoelectrically active material 40 generates only a high-frequency

Oscillation, the coupling elements 72, 74 on the roller support 52 effectively, and generates high-frequency oscillations in the range of 40kHz, for example, to solve a jammed saw blade to refine the chip formation or to facilitate the Sägeführung. In variation to this, as shown in FIG. 6 b, the micromoving movement can be a conventional sawing movement 24 in sawing direction 30 be superimposed with a stroke frequency of 40 Hz in order to achieve a high Sägefortschritt 32.

FIG. 7 shows in perspective a combined superposition of motor-generated sawing movements 24 with micro-working movements 28 which are generated by an ultrasonic excitation actuator 24 in different directions. FIG. 7 a illustrates the generation of a free-cutting movement 48 by means of an ultrasonic excitation actuator 38 Excitation actuator 38 acts at right angles to the roller support 52 in order to set the saw blade 18 in transverse oscillations, which effect a free cutting and can enlarge a sawing gap. Based on this, in FIG. 7b, a conventional 40 Hz sawing work movement 24 is superimposed on the micro-free-cutting movement 48 aligned orthogonally with respect to the sawing direction 30 and saw progressing direction 32. Finally, FIG. 7c shows a combination of a micro free-cutting movement 48 with a micro pendulum stroke movement 46 and a sawing work movement 24 overlaid by a micro-working movement 28. For this purpose, preferably three excitation actuators 38 can be used, two actuators 38 acting on the roller support 52 and a third Actuator 38 acts on the lift shaft of the saw blade 18. These combined Mikroarbeitsbewegungen 28 may be selectively activated, the conventionally produced sawing movement 24 may also be activated independently.

The saw blade 18 is typically moved back and forth in a sawing direction 30 by a sawing movement 24, wherein in the return stroke movement 46 in Sägefortschrittsrichtung 32 takes place to protect the saw blade 18. Both movements, the sawing movement 24 and the lifting movement 46 are superimposed by micro-working movements 28, which are generated by two separately activatable excitation actuators 38. Furthermore, a third excitation actuator 38 generates a microf rippling movement 48 in a clearing direction 34 transverse to the saw blade. The superimposed micro-motions 28 increase the quality of the cut, prevent the blade from tilting, reduce sawing noise, cause sawdust to be discarded, and enable clean saw cuts without large saw-edge injuries. In addition, frictional forces are reduced and the life of the saw blade 18 is increased. Finally, FIG. 9 shows a schematic diagram of a control of the excitation actuator 38, for example in the form of a piezoelectric actuator 40 with an AC voltage supply from a utility grid or a DC power supply with a battery pack. An electronic unit 36 arranged in the housing 14 serves to apply at least control and / or regulating signals to the excitation actuator 38 and to the voltage supply of the excitation actuator 38. An operating voltage unit 58, here designed as a battery or rechargeable battery pack with batteries or rechargeable batteries 60, is provided an electrical DC voltage for the electronic unit 36, which converts the operating voltage into a high-frequency voltage signal with which the excitation actuator 38 is excited to vibrate in the desired manner. The electronic unit 36 is designed to operate the at least one excitation actuator 38 at a resonant frequency f_res. In this case, the electronic unit 36 comprises a control unit 54 for tracking the resonance frequency f_res of the excitation actuator 38. The control unit 54 may comprise a phase locked loop which can excite the excitation actuator 38 at its resonant frequency, with a phase shift between the injected current and the injected voltage being set to 0 ° becomes. The resonance frequency f_res is preferably readjusted if the resonance frequency changes due to heating or load changes on the saw blade. Alternatively, a frequency tracking can also take place by regulating to a maximum of the current fed into the excitation actuator 38. When the power supply of the electronic unit 36, for example with 220 volts AC, a power supply 62 is provided which rectifies the AC voltage, reduces and smoothes. The electronic unit 36 comprises a power generation unit 64, into which the DC voltage is fed and which is coupled to the excitation actuator 38 via a corresponding filter unit 66. A control unit 54 provides the control signals for the excitation actuator 38. The operating frequency of the excitation actuator 38 is in the range between 10 kHz and 1000 kHz, preferably between 30 kHz and 50 kHz, in particular between 35 kHz and 45 kHz, more preferably about 40 kHz.

If the supply by the operating voltage unit 58 by means of batteries or rechargeable batteries 60, the space required can be reduced because the power supply unit 62 can be omitted for rectification and smoothing. The electrical output voltage of the operating voltage unit 58 is preferably below 100 volts, at about 36 volts or 10.8 volts.

Claims

claims

1 . Hubsäge (10), in particular stub, saber, or hacksaw at least comprising a housing (14),

a tool region (16) for a linearly and / or oscillatory drivable saw blade (18),

a housing-side operating part (20) for the user-side activation of a sawing movement (24),

a drive unit (22) arranged in the housing (14) for generating the sawing movement (24) of the saw blade (18),

an electronic unit (36) arranged in the housing (14) for acting upon the drive unit (22) with at least control and / or regulating signals,

wherein the drive unit (22) comprises at least one excitation actuator (38) having a volume of excitation-active material (40) for generating a micromachining movement (28)

is controlled or regulated in operation by the electronics unit (36),

characterized in that the excitation actuator (38) can superimpose the micro-working movement (28) at least on the sawing movement (24) of the saw blade (18).

2. Hubsäge (10) according to claim 1, characterized in that the drive unit (22) in addition to the at least one excitation actuator (38) at least one further drive component (50), in particular a drive motor, preferably an electric motor (42) for generating the Sawing work movement (24), in particular a lifting or jigsaw working movement (44) and / or a pendulum (46) and / or a free cutting movement (48).

3. Hubsäge (10) according to claim 3, characterized in that the at least one excitation actuator (38) can be activated separately from the at least one further drive component (50).

4. Hubsäge (10) according to any one of the preceding claims, characterized in that the micro-working movement (28) the Sägearbeitsbewegung (24) of the saw blade (18) in at least one of the following directions excited or superimposed:

in the direction of the sawing movement (24), in particular the jigsaw (44) and / or;

orthogonal to the sawing movement (24) of the saw blade (18) as a longitudinal pendulum movement (46) in the direction of Sägefortschritts and / or;

orthogonal to the sawing movement (24) of the saw blade (18) as a cross-pendulum or free-cutting movement (48) in the transverse direction to Sägefortschritt.

5. Hubsäge (10) according to claim 4, characterized in that the excitation actuator (38) acts on a bearing or roller support (52) of the lifting or jigsaw (10).

6. Hubsäge (10) according to one of the preceding claims, characterized in that the electronic unit (36) is adapted to operate the at least one excitation actuator (38) in a resonant frequency (f_res) and in particular a control unit (54) with frequency adaptation to Tracking the resonant frequency (f_res) of the at least one excitation actuator (38).

7. Hubsäge (10) according to any one of the preceding claims, characterized in that the excitation active material (40) of the excitation actuator (38) is piezoelectric or magnetostrictive.

8. Hubsäge (10) according to one of the preceding claims, characterized in that the at least one excitation actuator (38) on the tool tip has a vibration amplitude of at least 5 μηη, preferably up to 100 μηη, in particular 15 μηη.

9. Hubsäge (10) according to any one of the preceding claims, characterized in that the operating frequency of the at least one excitation actuator (38) in the range between 10 kHz and 1000 kHz, preferably between 20 kHz and 100 kHz, in particular between 35 kHz and 45 kHz ,

10 Hubsäge (10) according to any one of the preceding claims, characterized in that one or more optical and / or acoustic and / or haptische operating shots (56) are provided for an activated state of the at least one excitation actuator (38). Lifting saw (10) according to one of the preceding claims, characterized in that at least the drive unit (22), electronics unit (36) and operating voltage unit (58) are distributed in the housing (14), that a center of mass in the region of the handle portion (78).