EP2089192B1 - Mass oscillating unit for hand-held machine tools with a striking device - Google Patents

Abstract

The invention relates to a striking arrangement (12) for a hand-held machine tool with at least one mass oscillating unit (14), which is intended to generate a counterforce (16) to a force (18) resulting from the striking arrangement. The mass oscillating unit comprises at least one counter oscillating mass (20), which can be excited by means of a driven excitation means (38) counter to the driving direction (26) of the striking arrangement, and a spring element (22) supporting the counter oscillating mass, wherein the excitation means (24) is formed by an eccentric wheel (28a, 28b, 28c, 28d, 28e) or by a pneumatic means (30f). The counter oscillating mass (20) is preferably designed at least partially as a hammer tube (32e) and is provided with a safety mechanism in an idle position.

Description

State of the art

The invention relates to a handheld power tool impact device according to the preamble of claim 1.

From the patent application WO 2004/082897 For example, there is already known a portable power tool impact device with such features, which has a counterweight which is intended to generate a counterforce to a force resulting from an impact mechanism and in which the counterweight can be held in an idling position by means of retaining elements.

Advantages of the invention

According to the invention, a handheld power tool percussion device with a striking mechanism arrangement according to claim 1 is proposed, with at least one unit which is intended to generate a counterforce to a force resulting from the percussion mechanism, the unit being formed by a mass vibration unit is, wherein the mass vibration unit comprises a counterweight mass for striking mechanism arrangement, wherein the unit has a locking unit which is provided for securing the counterweight in an idle position, wherein the locking unit has at least one locking element and a fixing element and wherein for securing the counterweight in the axial direction of the Arresting element in a locking recess, which is arranged within the counter-vibration mass, is movable, wherein the fixing element is arranged movable within the locking element. In this way, an advantageous reduction of vibrations on a housing of a hand tool machine with a hand tool machine impact device, which are caused by the generation of a shock pulse of the impact mechanism, can be achieved. The generated counterforce and the force resulting from the hammer mechanism are preferably aligned in opposite directions, so that an advantageous and at least partial cancellation of the forces can be achieved in a vibration reduction and thus particularly advantageous a virtually vibration-free guidance for an operator of the power tool can be achieved. Conveniently, the unit is intended to generate the counterforce within a large speed range of a drive unit or a high impact frequency range of Schlagwerkanordnung so that the counterforce generated in the direction and time can be advantageously matched to a compression force of Schlagwerkanordnung and a maximum vibration reduction can be achieved , The unit may be designed as a mechanical, an electrical and / or a magnetic and / or a pneumatic unit and / or as further, the expert appears reasonable unit and thereby a mechanical, electrical and / or magnetic, etc. counterforce to generate resultant force of the percussion arrangement.

According to the invention it is proposed that the unit is formed by a mass vibration unit, which structurally simple means of a mechanical excitation, especially if the unit formed by the mass vibration unit has a counterweight, a counterforce generated by a counter-vibration to the compression force of the hammer mechanism can be achieved.

It is optionally proposed that the unit has at least one spring means which supports the counterweight mass, whereby, after an excitation of the counterweight mass, an advantageous return of the counterweight mass to the rest position or starting position can be achieved and thus a renewed and in particular periodic excitation of the counterweight mass can be achieved. In addition, acts by the spring means or by a spring force of the spring means an additional force on the countervailing mass against an acceleration direction of the countervailing mass, so that the counterforce of the unit can be advantageously increased. Preferably, the spring means supports the mating mass on a housing of the power tool.

Optionally, it is proposed that the unit has at least one excitation means which can be driven by means of a drive means of the hammer mechanism, whereby a structurally simple adaptation or coupling of the generated counter-vibration or the generated counterforce to a rotational speed of the drive unit or to a beat frequency of the striking mechanism arrangement can be achieved. In this case, the excitation means can be formed by an electrical, a magnetic and / or a mechanical excitation means and / or further excitation means which appear expedient to the person skilled in the art.

Optionally, it is proposed that the countervibration mass can be excited by means of the excitation means counter to a drive direction of the striking mechanism arrangement, whereby an advantageous cancellation of the counterforce and the resulting force of the striking mechanism arrangement can be achieved.

Optionally, it is proposed that the excitation means is formed by an eccentric wheel, so that in particular a periodic excitation of the countervibration mass is achieved can, wherein the eccentric wheel is preferably coupled to a beat frequency of the striking mechanism arrangement or a rotational speed of the drive unit.

According to the invention, it is proposed that the unit has a locking unit which is provided for securing the counterweight mass in an idling position. In this way, an undesired generation of large opposing forces during a standstill or a stay of a racket of Schlagwerkanordnung in a rest position can be advantageously avoided. In addition, undesired wear of the handheld power tool striking device can thus advantageously be avoided, and a high service life of individual components or units of the handheld power tool striking device can be achieved.

In addition, a handheld power tool with a handheld power tool striking device is proposed, and thus an advantageous ease of operation with a low and / or particularly advantageous with a virtually vanishing resulting vibration of the power tool housing for an operator of the power tool is achieved.

drawing

Further advantages emerge from the following description of the drawing. In the FIGS. 7 and 8th the drawing embodiments of the invention are illustrated. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art expediently also individually consider and summarize to meaningful further combinations.

Both Figures 1-6 and FIGS. 9-12 as well as the description of these figures are examples that facilitate the understanding of the invention.

Fig. 1

eine Handwerkzeugmaschine mit einer Handwerkzeugmaschinenschlagwerk- vorrichtung in einer schematischen Seitendar- stellung,

Fig. 2

die Handwerkzeugmaschinen- schlagwerkvorrichtung in einer schematischen Seitendarstellung,

Fig. 3

ein Exzenterrad der Handwerkzeugmaschinen- schlagwerkvorrichtung,

Fig. 4

eine zu Figur 2 alternative Handwerkzeugma- schinenschlagwerkvorrichtung in einer schema- tischen Ansicht von oben,

Fig. 5

die Handwerkzeugmaschinenschlagwerkvorrichtung aus Figur 2 mit einem Anschlagmittel in einer schematischen Ansicht von oben,

Fig. 6

die Handwerkzeugmaschinenschlagwerkvorrichtung aus Figur 2 mit einem weiteren Federmittel in einer schematischen Ansicht von oben,

Fig. 7

die erfindungsgemäße Handwerkzeugmaschinen- schlagwerkvorrichtung mit einer Arretierein- heit in einer schematischen Seitenansicht,

Fig. 8

die Handwerkzeugmaschinenschlagwerkvorrichtung aus Figur 7 mit einer direkten Anordnung der Arretiereinheit an einem Hammerrohr in einer schematischen Seitenansicht,

Fig. 9

eine weitere alternative Handwerkzeugmaschi- nenschlagwerkvorrichtung in einer schemati- schen Seitenansicht,

Fig. 10

die Handwerkzeugmaschinenschlagwerkvorrichtung aus Figur 9 mit einer alternativen Anregung in einer schematischen Ansicht von oben,

Fig. 11

eine weitere alternative Handwerkzeugmaschi- nenschlagwerkvorrichtung mit einer von einem Hammerrohr gebildeten Gegenschwingungsmasse in einer schematischen Seitenansicht und

Fig. 12

eine weitere alternative Handwerkzeugmaschi- nenschlagwerkvorrichtung mit einem Pneumatik- mittel als Anregungsmittel in einer schemati- schen Seitenansicht.

Show it:

Fig. 1

a handheld power tool with a handheld power tool impactor in a schematic side view,

Fig. 2

the hand tool machine impact device in a schematic side view,

Fig. 3

an eccentric wheel of the portable power tool machine,

Fig. 4

one too FIG. 2 alternative portable power tool impact device in a schematic view from above,

Fig. 5

the hand tool machine strike device FIG. 2 with a stop means in a schematic view from above,

Fig. 6

the hand tool machine strike device FIG. 2 with another spring means in a schematic view from above,

Fig. 7

the hand-held power tool impacting device according to the invention with a locking unit in a schematic side view,

Fig. 8

the hand tool machine strike device FIG. 7 with a direct arrangement of the locking unit on a hammer tube in a schematic side view,

Fig. 9

FIG. 2 is a schematic side view of another alternative hand-held power tool impact device;

Fig. 10

the hand tool machine strike device FIG. 9 with an alternative excitation in a schematic view from above,

Fig. 11

a further alternative hand tool machine impact device with a counterweight formed by a hammer tube in a schematic side view and

Fig. 12

a further alternative hand tool machine impact device with a pneumatic medium as an excitation means in a schematic side view.

In FIG. 1 is a handheld power tool 36a shown with a handheld power tool impactor device 10a. The handheld power tool impact device 10a ( FIG. 2 ) comprises a striking mechanism assembly 12a and a unit 14a formed by a mass vibration unit. The percussion arrangement 12a is for generating a impact impulse for a tool 40a, which is located in a tool holder 42a of the handheld power tool 36a ( FIG. 1 ), and for this purpose has a piston 44a, a pneumatic element 46a, a racket 48a and a firing pin, not shown. In addition, the percussion arrangement 12a comprises a hammer tube 32a, in which the piston 44a and the racket 48a along a drive direction 26a of the striking mechanism arrangement 12a are mounted axially movable. Between the piston 44a and the beater 48a, the pneumatic element 46a formed by an air cushion is arranged ( FIG. 2 ).

For a drive of the hammer mechanism arrangement 12a, a drive torque is generated by a drive unit of the handheld power tool 36a (not shown here in detail and formed by an electric motor). The drive unit transmits a drive torque to a drive means 38a formed by a drive shaft, which is oriented perpendicular to the drive direction 26a of the striking mechanism arrangement 12a ( FIG. 2 ). At one of the percussion arrangement 12a facing end 50a of the drive shaft, this has an eccentric drive unit 52a with a non-rotatably connected to the drive shaft eccentric 54a and a bolt-shaped eccentric pin 56a. The eccentric pin 56a is aligned perpendicular to a main extension surface 58a of the eccentric wheel 54a and perpendicular to the drive direction 26a of the hammer mechanism 12a and arranged in a region of the eccentric wheel 54a, which is arranged outside a drive shaft 60a of the eccentric wheel 54a formed by a rotation axis. The eccentric pin 56a is connected to the piston 44a via a drive rod 62a of the striking mechanism assembly 12a. By means of the eccentric drive unit 52a and the drive rod 62a of the striking mechanism arrangement 12a, an axial linear movement of the piston 44a along the drive direction 26a of the striking mechanism arrangement 12a is achieved during operation of the hand tool 36a from a rotational movement with a torque of the drive shaft ( FIG. 2 ).

The mass vibration unit is disposed in a portion of the portable power tool 36a, that of the drive shaft From the perspective, the drive direction 26a of the hammer mechanism 12a is opposite. In addition, the mass vibration unit has a counterweight 20a, a spring means 22a and an excitation means 24a formed by an eccentric wheel 28a. The eccentric 28a is driven via the drive shaft of the drive unit, which is provided for driving the hammer mechanism assembly 12a, and is rotationally connected thereto. The eccentric wheel 28a has a cam-shaped, asymmetrical shape of a main extension surface 64a, which, relative to a circular shape, in a center has a recess 66a for rotationally fixed attachment to the drive shaft ( FIG. 3 ). The eccentric 28a and a drive cam 68a of the mass vibration unit and the eccentric 54a and the eccentric pin 56a of the striking mechanism 12a run in the direction of rotation 72a with a phase shift of 180 ° about the drive shaft, so that the drive cam 68a of the eccentric 28a of the mass vibration unit in one of Drive direction 26a opposite end position is when the eccentric pin 56a of the eccentric 54a of the percussion mechanism assembly 12a is in an in the drive direction 26a facing end position ( FIG. 2 ).

By means of the cam-shaped eccentric wheel 28a, the counterweight 20a is moved counter to a drive direction 26a of the hammer mechanism 12a. The counterweight 20a is moved counter to a spring force of a spring means 22a, wherein the spring means 22a, the counterweight 20a is supported on a housing 70a of the power tool 36a. At a time of the end position of the eccentric pin 56a of the eccentric drive unit 52a pointing in the drive direction 26a, a maximum of a compression force acts formed force 18a of the percussion mechanism 12a against the drive direction 26a of the striking mechanism assembly 12a. By an excitation of the counterweight 20a by means of the cam-shaped eccentric 28a, a counterforce 16a is generated which reaches a maximum, due to the arrangement of the mass vibration unit, almost simultaneously to the maximum resultant force 18a of the impact mechanism 12a. The opposing force 16a of the mass vibration unit is in the opposite direction to the resultant force 18a of the percussion mechanism 12a, so that the resultant force 18a of the percussion mechanism 12a and the counterforce 16a in the area of the drive shaft cancel as far as possible and resulting oscillations of the handheld power tool 36a are at least reduced and / or avoided ( FIG. 2 ).

The spring means 22a of the mass vibration unit causes an automatic return of the counterweight 20a in the initial situation, the counterweight 20a after a periodic rotation about the axis of rotation of the drive shaft of the cam-shaped eccentric 28a again against the spring force of the spring means 22a and against the drive direction 26a of the striking mechanism 12a move. By means of the cam-shaped eccentric wheel 28a driven by the drive shaft, the counterforce 16a of the mass vibration unit is adapted to a momentary impact frequency of the striking mechanism arrangement 12a or to a direction and time of the force 18a resulting from the impact mechanism arrangement 12a. In addition, the spring means 22a causes an increased inertia when accelerating the counterweight 20a and the counterforce 16a thus acts over a longer period against the resulting force 18a of the impact mechanism assembly 12a.

In the FIGS. 4 to 12 Alternative examples or embodiments of the invention are shown. Substantially identical components, features and functions are basically numbered by the same reference numerals. To distinguish the examples, however, the reference numerals of the embodiments, the letters a to f are added. The following description is essentially limited to the differences from the example in FIGS FIGS. 1 to 3 , wherein with respect to the same components, features and functions on the description of the example in the FIGS. 1 to 3 can be referenced.

The FIGS. 4 to 6 show an alternative portable power tool impactor apparatus 10b. An eccentric 28b for exciting a counterweight 20b is also provided for driving a striking mechanism 12b. For this purpose, the eccentric wheel 28b has two eccentric pins 56b, 74b which are arranged on mutually opposite edge regions 76b, 78b of the eccentric wheel 28b. In addition, the eccentric pin 74b extends for excitation of the counterweight 20b on a side facing away from the eccentric pin 56b to drive the striking mechanism 12b side of the eccentric 28b perpendicular to a main extension surface 64b of the eccentric 28b.

On the counterweight 20b another spring means 80b is arranged on a side facing in a drive direction 26b side. The spring means 80b allows a muted coupling of the eccentric pin 74b to the counterweight mass 20b, wherein the eccentric pin 74b has a direction of movement in a direction of rotation 72b of the eccentric 28b and a drive shaft. The eccentric pin 74b coupled to a Timing to the spring element 80b, in which a compression force is built up in the hammer mechanism assembly 12b. As the eccentric wheel 28b turns further, a compression force or a resultant force 18b increases against the drive direction 26b in the striking mechanism arrangement 12b and at the same time the countervailing mass 20b is pressed counter to the drive direction 26b and thus a counterforce 16b is generated by an acceleration of the countervailing mass 20b. If the eccentric pin 56b is located in an end position facing the striking mechanism arrangement 12b or if the eccentric pin 74b is located in an end position facing the counterweight 20b, a maximum force 18b results from the striking mechanism arrangement 12b against the drive direction 26b and from the mass vibration unit results in a maximum counterforce 16b in the direction of the drive direction 26b, wherein the force 18b and the counterforce 16b cancel each other at least partially.

Unlike the arrangement in FIG. 4 points into the Figures 5 and 6 the mass vibration unit on a stop means 82b, which is arranged in the drive direction 26b of the striking mechanism assembly 12b after the other spring means 80b. The stop means 82b prevents excessive back movement of the counterweight 20b by means of a spring means 22b and positions the counterweight 20b in a starting position for a renewed excitation by means of the eccentric wheel 28b.

In FIG. 6 if the stop means 82b is additionally coupled to the counterweight 20b with a spring element 84b, to prevent undesirable abutment of the spring means 80b and / or the countermass 20b on the stop means 82b. In addition, the counterweight 20b is positioned by means of the spring means 22b for support on the housing 70b of the power tool and the spring element 84b in a starting position for a new excitation.

In the FIGS. 7 and 8th a handheld power tool impactor device 10c according to the invention is shown with a locking unit 34c which is provided for securing a counterweight mass 20c in an idling position. In FIG. 7 For this purpose, the locking unit 34c has a spring element 86c, a locking element 88c, a fixing element 90c and a retaining ring 92c arranged on a hammer tube 32c. The spring element 86c supports the locking element 88c on a housing 70c of a hand-held power tool and is arranged in a chiseling operation in a prestressed position. The fixing element 90c is fixedly connected to the retaining ring 92c with an end 94c pointing in a drive direction 26c and movably arranged with the other end 96c within the locking element 88c. For this purpose, the locking element 88c has a recess 98c, which tapers in a direction which extends counter to the drive direction 26c, in which the fixing element 90c is arranged to be axially movable. By means of a displacement of the fixing element 90c in an axial direction 100c of the fixing element 90c, the locking element 88c, caused by the tapered recess 98c, moves perpendicular to the axial direction 100c of the fixing element 90c. The spring element 86c causes a displacement of the fixing element 90c in the drive direction 26c or a displacement of the tapered recess 98c Moving the locking member 88c upward or a movement of the locking member 88c, which is directed away from the housing 70c of the power tool. As soon as the counterweight 20c is maximally accelerated and is in a contactless position with an eccentric wheel 28c, the locking element 88c moves into a locking recess 102c, which is arranged inside the counterweight 20c, so that the counterweight 20c is secured in the axial direction 100c. The idle position is coupled to an idle position of a striking mechanism 12c. In the idling position of the striking mechanism arrangement 12c, the hammer tube 32c is displaced together with the retaining ring 92c in a drive direction 26c, and thus the fixing element 90c moves in the axial direction 100c out of the tapering recess 98c of the locking element 88c ( FIG. 7 ).

When the idling position of the hammer mechanism 12c is released, the hammer tube 32c is pushed together with the retaining ring 92c to a normal bit operating position, and the fixing member 90c is pressed into the tapered recess 98c of the locking member 88c against the driving direction 26c. As a result, the locking element 88c is pressed against the spring force of the spring element 86c from the locking recess 102c of the counterweight 20c and the counterweight 20c brought by the spring means 22c in a starting position for a renewed excitation by the eccentric 28c ( FIG. 7 ).

The locking unit 34c in FIG. 8 differs from the locking unit 34c in FIG. 7 by a direct arrangement of the fixing element 90c on the hammer tube 32c, which has a holding element 104c for this purpose.

In the Figures 9 and 10 there is illustrated a portable power tool impactor device 10d having a counterweight 20d which is cylindrically disposed around a hammer tube 32d of a striking mechanism assembly 12d. The counterweight 20d is thereby excited counter to a drive direction 26d of the impact mechanism 12d to a counter vibration, which generates a counter force 16d to a resultant force 18d of the impact mechanism 12d. The counterweight 20d is supported by a spring means 22d on a housing 70d of a hand tool, wherein the spring means 22d is arranged on one of the drive direction 26d of the hammer mechanism 12d opposite end 124d of the counterweight 20d. In the drive direction 26d after the counterweight 20d a stop means 126d arranged on the housing 70d of a hand tool that stops the counterweight 20d in a swing back to a starting position for a new excitation and prevents unwanted further movement of the counterweight 20d in the direction of the drive direction 26d.

In FIG. 9 For example, the counterweight 20d arranged around the hammer tube 32d is excited to counter oscillations via an eccentric gear 28d different from an eccentric gear 54d for driving the hammer mechanism 12d. The counterweight 20d is excited via an excitation rod 128d, which is set into an axial movement via the eccentric wheel 28d.

In FIG. 10 For example, the counterweight 20d arranged around the hammer tube 32d is driven via the eccentric gear 28d to drive the hammer mechanism 12d. In addition, the excitation rod 128d has an axial guide 130d aligned in the drive direction 26d for exciting the counterweight 20d.

FIG. 11 shows a portable power tool impact device 10e with a counterweight 20e of a mass vibration unit formed by a hammer tube 32e. An operation and an excitation of the counterweight 20e correspond to the example in FIG FIG. 9 ,

FIG. 12 shows a portable power tool impact device 10f with an excitation means 24f formed by a pneumatic means 30f. For this purpose there is a counterweight 20f of a mass vibration unit in a housing 110f of the mass vibration unit. The housing 110f of the mass vibration unit has a cylindrical shape with two valves 132f, 134f. In the housing 110f, the counterweight 20f, which is disk-shaped, is excited to counter vibrations of a hammer mechanism 12f, so that the counterweight 20f generates a counterforce 16f to a resultant force 18f of the hammer mechanism 12f. For this purpose, the counterweight 20f is supported on the housing 110f by means of a spring means 22f thereon. The two valves 132f, 134f are disposed on opposite housing walls 136f, 138f of the housing 110f, one of the two valves 132f for supplying air and the other of the two valves 134f for discharging air. The valve 132f for supplying Air is connected to a pneumatic element 46f of the impact mechanism assembly 12f via an air line 140f. Air is conducted via the air line 140f or the valve 132f by means of an overpressure in the pneumatic element 46f of the striking mechanism arrangement 12f into the housing 110f of the mass vibration unit and an overpressure is generated in the mass vibration unit. The positive air pressure in the housing 110f of the mass vibration unit pushes the counterweight 20f counter to a drive direction 26f of the hammer mechanism 12f against a spring force of the spring means 22f against the housing 110f, so as to produce a counter force 16f generated to the hammer mechanism 12f. When the countermass 20f is located at a minimum distance from the housing 110f of the mass vibration unit by means of the overpressure in a drive direction 26f, the valve 134f for discharging air from the counterweight 20f is uncovered within a portion 142f of the housing 110f with the overpressure , air can be discharged into the hand tool. This results in a backward movement of the counterweight 20f in the drive direction 26f, wherein the valve 134f for discharging air in a starting position for re-excitation of the counterweight 20f is covered, so that a removal of the air before reaching a maximum counterforce 16f to the striking mechanism assembly 12f avoided becomes.

Claims (4)

1. Percussion mechanism apparatus for a portable power tool, comprising a percussion mechanism arrangement (12) and at least one unit (14) which is provided for generating a counterforce (16) to a force (18) resulting from the percussion mechanism arrangement (12), wherein the unit (14) is formed by a mass oscillating unit, wherein the mass oscillating unit has a counter oscillating mass (20c) relative to the percussion mechanism arrangement (12), wherein the unit (14) has a locking unit (34c) which is provided for securing the counter oscillating mass (20c) in an idling position, wherein the locking unit (34c) has at least one locking element (88c) and a fixing element (90c), and wherein, to secure the counter oscillating mass (20c) in the axial direction (100c), the locking element (88c) can be moved into a locking recess (102c) which is arranged within the counter oscillating mass (20c), characterized in that the fixing element (90c) is arranged so as to be movable within the locking element (88c).
2. Percussion mechanism apparatus for a portable power tool according to Claim 1, characterized in that the unit (14) has at least one spring means (22) which supports the counter oscillating mass (20), wherein the unit (14) has at least one excitation means (24) which can be driven by a drive means (38) of the percussion mechanism arrangement (12), and wherein the counter oscillating mass (20) can be excited by the excitation means (24) against a drive direction (26) of the percussion mechanism arrangement (12).
3. Percussion mechanism apparatus for a portable power tool according to Claim 2, characterized in that the excitation means (24) is formed by an eccentric wheel (28a; 28b; 28c; 28d; 28e).
4. Portable power tool having a percussion mechanism apparatus for a portable power tool according to one of the preceding claims.

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