EP1404493B1 - Hand tool machine comprising a vibration-dampened handle - Google Patents

Abstract

The aim of the invention is to ensure a coupling between the handle (2) and the machine housing (1) of the hand tool machine which dampens the vibrations thereof as much as possible. The handle (2) is coupled to the machine housing (1) by at least two parallel levers (4, 5) which are essentially perpendicular to the longitudinal axis (3) of the hand tool machine. The levers (4, 5) are hingedly connected to both the machine housing (1) and the handle (2).

Description

State of the art

The present invention relates to a handheld power tool with vibration-damped handle according to the features of the preamble of claim 1.

In particular, in manual power tools with a beating drive, z. As rotary hammers, chipping hammers and the like, quite strong vibrations in the machine, which are transmitted to the handle of the machine and are not only unpleasant for the operator, but can also be harmful to health. For example, from DE 195 03 526 A1 or US 5,697,456 measures are known to dampen the handle of a power tool against vibration. These measures exist z. Example, in that the handle is coupled at one end via a damping spring or a spring system with the machine housing and that the handle is connected at the opposite end by means of a rotary joint with the machine housing. In DE 195 03 526 A1 it is also proposed that the handle at both ends via a vibration-damping material, for. B. thermoplastic elastomeric plastic, is connected to the machine housing. So far, it is usual to connect the handle in two places with the machine housing. Even if one or both coupling points are provided with damping means, still finds a relatively high coupling of vibrations from the machine housing to the handle instead.

From WO 98/21014 it is known to use one or more active, electrically controllable damping elements for vibration damping between the handle and the machine housing, which counteract vibrations of the machine housing.

From US 5,025,870 a hand tool with vibration-damped handle is known, wherein the handle is coupled via two parallel, almost perpendicular to the longitudinal axis of the power tool aligned lever with the machine housing and the two levers are articulated on the one hand on the machine housing and the other hand on the handle. The vibration damping of hand grips in hand tool machines by means of parallel oscillators, consisting of two parallel leaf springs is known from EP 0 849 492 A2.

The invention is therefore based on the object to provide a hand tool with a handle of the type mentioned, which is coupled vibration-damped with space-saving means to the machine housing of the power tool and has a high stability.

Advantages of the invention

The above object is achieved with the features of claim 1, characterized in that the handle is coupled via two or more parallel, aligned almost perpendicular to the longitudinal axis of the power tool lever with the machine housing, wherein the levers are hinged on the one hand on the machine housing and the other hand on the handle and at least one of the levers is disposed in a leg of the handle extending approximately perpendicularly to the longitudinal axis of the portable power tool and the at least one other lever is arranged in the machine housing. With such a so-called parallel oscillator of the handle gets a fairly high stability and, because he no longer has direct connection points with the machine housing more, very strongly decoupled from vibrations of the machine housing. In addition, the parallel oscillator is integrated to save space in the hand tool.

Advantageous developments of the invention will become apparent from the dependent claims.

It is expedient that with each lever, the articulation point on the handle is as far away as possible from the articulation point on the machine housing. This ensures that the relative movement between the handle and the machine housing has almost exclusively a component in the direction of the longitudinal axis of the power tool. It is advantageous that the distances between their two articulation points are almost equal in all levers, whereby unwanted movement effects of the handle can be avoided.

The vibration damping for the handle can be further increased by the fact that at one or more points between the handle and the machine housing spring elements - preferably compression springs - are inserted. A further improvement of the vibration damping can be achieved by disposing one or more active damping elements between the handle and the machine housing instead of purely passive spring elements, which are controllable in such a way that they counteract vibrations of the machine housing.

The levers are particularly vibration-damping, if they are designed as leaf springs. Advantageously, the Leaf springs biased against a force exerted on the handle in the direction of the machine housing force.

It is expedient to limit the relative movement of the handle relative to the machine housing by one or more stops.

drawing

• Figur 1 eine Prinzipdarstellung eines nicht erfindungsgemäßen mittels eines Parallelschwingers am Maschinengehäuse gelagerten Handgriffs,
• Figur 2 eine praktische Ausführung des an einem Maschinengehäuse mittels eines Parallelschwingers gelagerten Handgriffs,
• Figur 3 eine nicht erfindungsgemäße Handwerkzeugmaschine, bei dem der Pedalschwinger aus Blattfedern besteht,
• Figur 4 eine nicht erfindungsgemäße Handwerkzeugsmaschine mit einem Parallelschwinger und einem zwischen Handgriff und Maschinengehäuse eingesetzten Dämpfungselement und
• Figur 5 eine nicht erfindungsgemäße Handwerkzeugsmaschine mit einem aus vorgespannten Blattfedern bestehenden Pärallelschwinger.

On the basis of several embodiments shown in the drawings, the invention is explained in more detail below. Show it:

• 1 shows a schematic representation of a not according to the invention by means of a parallel oscillator mounted on the machine housing handle,
• 2 shows a practical embodiment of the handle mounted on a machine housing by means of a parallel oscillator,
• FIG. 3 shows a hand tool machine not according to the invention, in which the pedal oscillator consists of leaf springs,
• FIG. 4 shows a hand-held power tool not according to the invention with a parallel oscillator and a damping element inserted between the handle and the machine housing, and FIG
• FIG. 5 shows a hand-held power tool not according to the invention with a parallel vibrator consisting of prestressed leaf springs.

Description of exemplary embodiments

In the figure 1 is schematically a hand tool, for. As a hammer drill or chisel or the like. The hand tool machine consists of a machine housing 1, in which the machine drive located, and a coupled to the machine housing 1 handle. 2

The handle 2 is coupled via a parallel rocker with the machine housing 1. This parallel rocker consists of two mutually parallel, almost perpendicular to the longitudinal axis 3 of the machine aligned levers 4 and 5. Instead of the two levers 4 and 5 shown in the drawing, more than just two parallel levers can be used. The levers 4 and 5 are articulated on the one hand on the handle 2 and on the other hand on the machine housing 1 so that the handle 2 can perform a relative movement relative to the machine housing 1 almost exclusively in the direction of the longitudinal axis 3.

So that only the smallest possible Kippbewegungsanteil can arise between the handle 2 and the machine housing 1, the pivot point should be 6 or 7 on the handle 2 as far as possible from the pivot point 8 and 9 on the machine housing 1 at each lever 4 and 5 respectively. To meet this condition as well as possible, the pivot points 6, 7 for the two levers 4, 5 at the upper end, preferably a parallel to the longitudinal axis 3 extending leg 10, the handle 2 are arranged. The other two pivot points 8 and 9 of the levers 4 and 5 are located on a present at the lower end of the machine housing 1 carrier 11. The pivot points 6, 7, 8, 9 of the individual levers 4, 5 are placed so that each lever. 4 , 5 the two pivot points 6, 8 and 7, 9 have the same distances from each other. Namely, at different distances, unwanted movement effects on the handle - movement components, which differ from a movement of the handle in the direction of the machine longitudinal axis - arise.

Between the upper end, the horizontally extending leg 10, the handle 2 and the machine housing 1 damping means 12, preferably one or more compression springs, are inserted.

Due to the running via a parallel rocker coupling between the handle 2 and the machine housing 1, no direct connection points between the two arise, so that vibrations in the machine housing 1 are only very heavily attenuated transmitted to the handle 2.

In the figure 1, the coupling of the handle 2 to the machine housing 1 by means of a parallel rocker is shown very schematically in order to make clear the principle of operation.

FIG. 2 shows an exemplary embodiment of the inventive coupling of a handle 2 to a machine housing 1 of a hand-held power tool that is oriented towards a practical implementation. All parts already described in connection with FIG. 1 and carrying out the same function are provided in FIG. 2 with the same reference numerals as in FIG.

It can be seen from FIG. 2 that a stop 13 on the machine housing 1 and a stop 14 on the handle 2 are arranged for the compression spring 12 used as damping means between the handle 2 and the machine housing 1.

The very space-saving accommodation of the parallel vibrator is effected in that at least one of the levers 4, 5 is accommodated in the leg of the handle 2 extending perpendicularly to the longitudinal axis 13 of the hand tool machine. For this purpose, the support 11 arranged on the machine housing 1 projects for the articulation point 9 of the lever 5 as far as the leg of the lever running perpendicular to the longitudinal axis 3 Handle 2 before. The lower end of this perpendicular to the longitudinal axis 3 extending leg of the handle 2 may be provided with a support 11 surrounding the nozzle 15. This nozzle 15 forms only a conclusion between the carrier 11 and the handle 2, but he does not have the function of a mechanical guide for the handle second

The further the levers 4, 5 of the parallel oscillator are arranged away from each other, the greater the stability of the handle. In this respect, the embodiment in Figure 2, in which the one lever 4 in the machine housing 1 and the other lever 5 is arranged relatively far away from the lever 4 in the handle 2, leading to a high stability of the handle 2. The width (in the direction perpendicular to Drawing plane) of the lever 4, 5 has a stability-enhancing effect.

The parallel vibrator described, consisting of the levers 4, 5 can be arranged on only one side of the handle 2, as shown in Figures 1 and 2; but it can also be on both sides - seen in the direction transverse to the longitudinal axis 3 of the machine - the handle 2 parallel oscillator.

3, the relative movements of the handle 2 relative to the machine housing 1 are limited by an upper stop 16 and a lower stop 17. The two stops 16 and 17 are integrally formed on the horizontal leg 10 of the handle 2. These two stops 16 and 17 may be, for example, inner walls of a recess in the horizontally extending leg 10 of the handle 2. In these Recess 18 protrudes a firmly connected to the machine housing 1 arm 19. The movement of the handle 2 away from the machine housing 1 is limited by the fact that the arm 19 abuts against the lower stop 17. The movement of the handle 2 towards the machine housing 1 is limited by the fact that the arm 19 strikes the upper stop 16. The distance between the two stops 16 and 17 thus provides the range of motion for the handle 2. In reversal to the illustrated embodiment, the two stops 16 and 17 may also be arranged on the machine housing 1 and the arm 19 on the handle 2. It can also be provided only an upper or lower stop on the machine housing 1 and the handle 2.

In the case of the handheld power tool shown in FIG. 1 and in the exemplary embodiment shown in FIG. 2, the levers 4 and 5 forming the parallel oscillator are rigid. In the hand tool machines shown in FIGS. 3 to 5, the levers 20 and 21 are designed as leaf springs. The two leaf springs 20 and 21 are on the one hand in the horizontal leg 10 of the handle 2 and on the other hand on the housing 1, for example, on the carrier 11, anchored. The leaf springs 20 and 21 are aligned with their broad sides transversely to the direction of movement of the handle 2, so that they are flexible in the direction of the longitudinal axis 3 of the power tool and in the direction transverse to stiff. Due to the resilient action of the levers 20, 21 of the parallel oscillator, outgoing vibrations from the machine housing 1 in the direction of the handle 2 can be absorbed to a high degree.

Because of the resilient action of the leaf springs designed as levers 20 and 21 may possibly, as shown in Figure 3, are dispensed with the inserted between the housing 1 and the handle 2 spring elements 12.

However, a spring element can be used in addition to receiving vibrations between the machine housing 1 and the handle 2, or as shown in Figure 4, to be replaced by an active damping element 22, the z. B. eletrisch is controlled so that it counteracts vibrations of the machine housing 1. Active damping elements that are used in portable power tools for vibration damping of the handle are, for. B. from WO 98/21014 or EP 0 206 981 A2. In principle, such active damping elements consist of a magnetic coil 23 slidably mounted on a plunger coil 24, wherein the plunger coil on the handle 2 and the magnetic core 23 on the machine housing 1 and the plunger 24 on the machine housing 1 and the magnetic core 23 is attached to the handle 2. On the exact operation of this active attenuator will not be discussed in detail, since embodiments thereof are well known in the prior art. In principle, however, an active damping element functions such that the relative movement of the handle 2 relative to the machine housing 1 or the force exerted on the handle 2 is sensed and the current through the plunger coil 24 is controlled as a function of the measured relative movement or force.

Notwithstanding the illustrated examples, more than one spring element or more than just an active damping element can be used between the handle 2 and the machine housing. The combination of spring element and active damping element is possible.

In the case of the hand-held power tool shown in FIG. 5, the parallel oscillator is formed by two leaf springs 25 and 26, which are bent in such a way that they engage the handle 2 with its lower stop 17 Press the preload against the fixed arm 19. To overcome this bias, a certain force must be exerted on the handle 2. With appropriate adjustment of the bias of the leaf springs 25 and 26 is achieved that at an average process force of z. B. 100N the handle 2 is moved so far that the fixed arm 19 is in the middle between the two stops 16 and 17. This can be avoided that it comes during the work process to a hard stop of the arm 19 to the two stops 16 and 17. 5, a damping element, as shown in FIGS. 1, 2 and 4, can be inserted between the machine housing 1 and the horizontally extending limb 10 of the handle 2.

Claims (8)

1. Hand-operated machine tool with a vibration-damped handle (2) which is coupled to the machine housing (1), using damping means (12), the handle (2) being coupled to the machine housing (1) via two or more parallel levers (4, 5, 20, 21, 25, 26) oriented virtually perpendicularly with respect to the longitudinal axis (3) of the hand-operated machine tool, and the levers (4, 5, 20, 21, 25, 26) being articulated, on the one hand, on the machine housing (1) and, on the other hand, on the handle (2), characterized in that at least one of the levers (5) is arranged in a leg of the handle (2) which runs approximately perpendicularly with respect to the longitudinal axis (3) of the hand-operated machine tool, and the at least one other lever (4) is arranged in the machine housing (1).
2. Hand-operated machine tool according to Claim 1, characterized in that, on each lever (4, 5, 20, 21, 25, 26), the articulation point (6, 7) on the handle (2) is as far as possible from the articulation point (8, 9) on the machine housing (1).
3. Hand-operated machine tool according to either one of Claims 1 and 2, characterized in that, on all the levers (4, 5, 20, 21, 25, 26), the distances between their respective two articulation points (6, 7, 8, 9) are virtually identical.
4. Hand-operated machine tool according to Claim 1, characterized in that the handle (2) is supported on the machine housing (1) at one or more points via a spring element (12), preferably a compression spring.
5. Hand-operated machine tool according to Claim 1, characterized in that an active damping element (22), which can be controlled such that it counteracts vibrations of the machine housing (1), is arranged at one or more points between the handle (2) and the machine housing (1).
6. Hand-operated machine tool according to one of Claims 1 to 3, characterized in that the levers are leaf springs (20, 21, 25, 26).
7. Hand-operated machine tool according to Claim 6, characterized in that the leaf springs (25, 26) are prestressed counter to a force exerted on the handle (2) in the direction of the machine housing (1).
8. Hand-operated machine tool according to one of the preceding claims, characterized in that the relative movement of the handle (2) with respect to the machine housing (1) is limited by one or more stops (16, 17).

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