EP4234168A1 - Impact wrench with damper - Google Patents

Abstract

The invention relates to an impact wrench (10) comprising a rotary impact drive (22), the rotary impact drive (22) having a drive shaft (28) running along a longitudinal axis (L), the rotary impact drive (22) having a rotary impact drive (22) which is arranged displaceably along the longitudinal axis (L). Beater (30) and an anvil (32) that can be contacted by the beater (30) along a circumferential direction (U) to the longitudinal axis (L). According to the invention, the rotary percussion drive (22) has at least one shock absorber (40, 42, 44) which is set up to absorb an impact of the percussion (30) in a longitudinal percussion direction (LR) parallel to the longitudinal axis (L), in particular on the anvil (32). , to dampen. As a result, unwanted vibrations can be reduced or avoided, so that health risks when using the impact wrench (10) can be reduced.

Description

The invention relates to an impact wrench comprising a rotary impact drive.

With the help of rotary impacts, a rotary impact drive of an impact wrench can develop high torques, for example for tightening or loosening a screw.

However, relatively strong vibrations can often occur when using an impact wrench. Health risks from the noise associated with this or from vibrations transmitted to a user's body therefore often stand in the way of prolonged use of an impact wrench.

It is therefore the object of the present invention to offer an impact wrench, the use of which is expected to result in fewer health risks.

The object is achieved by an impact wrench comprising a rotary percussion drive, the rotary percussion drive having a drive shaft running along a longitudinal axis, the rotary percussion drive having a beater arranged to be displaceable along the longitudinal axis and an anvil that can be contacted by the beater along a circumferential direction to the longitudinal axis, and the rotary percussion drive having at least has a shock absorber which is set up to dampen an impact of the racket in a longitudinal direction of impact parallel to the longitudinal axis.

The impact of the club can take place in particular on the anvil. Alternatively or in addition, the impact of the beater can also occur on the drive shaft or on a part of the rotary percussion drive that is connected to the drive shaft and/or the anvil.

During operation of the impact wrench, the hammer can hit the anvil in particular along the longitudinal axis and also along the circumferential direction.

Undesirable vibrations can arise as a result of the impact, in particular repeated impacts, of the hammer on the anvil along the longitudinal direction of impact. The at least one shock absorber can reduce the amount of these unwanted vibrations or eliminate these vibrations altogether.

Impairments to the health of a user of the impact wrench can thus be minimized or completely avoided due to the reduced or completely prevented vibrations.

In particular, undesired vibrations can be reduced or completely avoided at the source and/or at the time when they may arise. Additional vibration-damping measures can be dispensed with. For example, it may be obsolete to mount the rotary percussion drive within a housing of the impact wrench in a vibration-damped manner on the housing. Alternatively, it is conceivable to provide such a vibration decoupling of the rotary percussion drive from the housing in order to achieve a further reduction in vibrations that can be transmitted to the housing, in particular a handle of the housing, and/or to the user.

The shock absorber can be formed between the racquet and the anvil. It can be located on an impact surface on the anvil pointing in the opposite direction to the longitudinal direction of impact.

Forming a shock absorber in such an area can be very cost-effective. It has also been shown that a significant proportion of the unwanted vibrations can be avoided.

Alternatively or additionally, the shock absorber can be formed between the racquet and the drive shaft. If the shock absorber is formed between the hammer and the drive shaft, the drive shaft can be coupled directly and/or indirectly to the anvil. Thus, a relative movement of the hammer relative to the anvil in the direction of longitudinal impact can be damped and/or damped.

A further reduction in vibrations can be achieved if a recoil damper moves between a rear side of the racquet pointing counter to the direction of longitudinal impact and one opposite the anvil against the direction of longitudinal impact of the racket along the longitudinal axis is formed delimiting the recoil surface.

The shock absorber may comprise a material from which the anvil is not formed and/or which the anvil does not comprise.

The at least one shock absorber can have, for example, a plastic and/or a material containing latex, for example a material containing rubber, in particular rubber. Such materials are available at low cost and can develop an adequate damping effect.

The shock absorber can be designed to dampen the impact in an inelastic or at least partially inelastic manner. For example, it can be designed to absorb at least 50 percent of the kinetic energy generated by the movement of the racket along the longitudinal axis.

The damping effect can also be tuned and/or tunable to a particular rotary impact drive and/or a particular impact wrench by varying material parameters. For example, parameters such as a peak power of the impact wrench, a typical power of the impact wrench, a rotational frequency, a peak pulse and/or the like can be taken into account for the tuning.

The shock absorber can also have a fluid, in particular a liquid containing oil and/or water, a gas, in particular air. This allows a pneumatic and/or hydraulic shock absorber to be implemented, for example. The damping effect of the shock absorber can be adjustable. For example, the fluid can contain a substance with an adjustable viscosity. The viscosity can be adjusted, for example, electrically and/or magnetically.

The shock absorber can be designed to have speed- and/or acceleration-dependent damping. In particular, it can be designed to produce a stronger damping effect as the relative speed between the racquet and the drive shaft increases. Alternatively or additionally, it can be designed to develop stronger damping with increasing relative acceleration between the racquet and the drive shaft. Alternatively or additionally, it is also conceivable for the shock absorber to have a variable, in particular adjustable, damping effect. He can for example, have an electro- and/or magnetorheological fluid. The fluid can be dilatant. In general, the fluid can exhibit non-Newtonian behavior.

The shock absorber can have hydraulics and/or pneumatics.

Further features and advantages of the invention result from the following detailed description of exemplary embodiments of the invention, using the figures of the drawing, which show details essential to the invention, and from the claims. The features shown there are not necessarily to be understood to scale and are presented in such a way that the special features according to the invention can be made clearly visible. The various features can each be implemented individually or in groups in any combination in variants of the invention.

In the schematic drawing, exemplary embodiments of the invention are shown and explained in more detail in the following description.

Show it:

• 1 an impact wrench in a partially sectioned view; and
• 2 a sectional view of a rotary percussion drive of the impact wrench according to 1 .

In the following description of the figures, the same reference symbols are used in each case for identical or functionally corresponding elements in order to facilitate understanding of the invention.

1 shows an impact wrench 10 in a partially sectioned side view. First of all, a housing 12 can be seen, from which a tool holder 14 protrudes. A handle area 16 with an operating element 18 is formed on the housing 12 . The operating element 18 can be set up, for example, to switch it on and/or off and/or to regulate an operating parameter of the impact wrench 10, for example a speed.

A battery pack 20 is used to supply energy to the impact wrench 10. The battery pack 20 has rechargeable batteries containing lithium. The impact wrench 10 can thus be operated wirelessly. The battery pack 20 can have a capacity of at least 20 Wh. The battery pack 20 can be set up to provide an electrical output of at least 400 W, in particular as a peak output, for example for up to 60 seconds, in particular 10 seconds to provide.

The impact wrench 10 also has a rotary impact drive 22 . The rotary percussion drive 22 is arranged within the housing 12 . It is shown in a partially sectioned view in area II, III .

The operating element 18 can - as in 1 - be arranged in a half of the handle area 16 pointing away from the rotary percussion drive 22 . For this purpose, it can be arranged, for example, in the vicinity of the battery pack 20, for example adjacent to a battery receptacle 24 for receiving the battery pack 20. This arrangement of the operating element 18 can prompt a user of the impact wrench 10 to grip it in a low-vibration area. Thus, stresses on the user due to vibrations can be further reduced.

2 shows an enlarged representation of the area II , III 1 Details of rotary percussion drive 22.

The rotary percussion drive 22 has a motor 25 which drives a drive shaft 28 via a gear 26, for example a planetary gear. The drive shaft 28 defines a longitudinal axis L of the impact wrench 10 (see FIG 1 ).

It drives a beater 30 , which in turn strikes an anvil 32 by rotary impacts. In particular, the beater 30 can contact the anvil 32 along a circumferential direction U around the longitudinal axis L and in particular hit it. In 2 corresponds to the circumferential direction U of a direction perpendicular to the image plane 1 and is therefore in 2 only shown symbolically.

The anvil 32 is connected to the tool holder 14 (see 1 ) connected, so that a tool arranged on the tool holder 14 can be driven, in particular in a rotary percussive manner.

The beater 30 is arranged to be displaceable along the drive shaft 28 and thus parallel to the longitudinal axis L. When the drive shaft 28 rotates about the longitudinal axis L, the beater 30 is driven forward in a longitudinal impact direction LR parallel to the longitudinal axis L, in particular in the direction of the anvil 32 and thus in the direction of the tool holder 14 .

A return spring 38 arranged between a rear section 36 of the drive shaft 28 and a rear side of the hammer 30 is set up to return the hammer 30 to a starting position, in particular counter to the longitudinal direction of impact LR, when the drive shaft 28 slows down or comes to a standstill.

A shock absorber 40 is formed on the anvil 32 in this embodiment. In particular, the shock absorber 40 is located between the beater 30 and the anvil 32. It is arranged on the anvil 32 for this purpose.

If the impact wrench 10, for example by means of the operating element 18 (see 1 ), put into operation, the bat 30 is accelerated along the longitudinal direction of impact LR.

It can happen, particularly at high speeds of the beater 30 along the longitudinal direction LR, that the beater 30 strikes the anvil 32 along the longitudinal direction LR. However, such impacts or impacts are dampened by the shock absorber 40 located in between. In this way, vibrations due to such impacts along the longitudinal impact direction LR can be avoided or at least reduced.

The shock absorber 40 can have a plastic and/or a rubber-containing material, for example rubber.

When the racquet 30 is driven back by the return spring 38, it may hit the rear portion 36 with a rear side. In order to absorb such an impact, a recoil absorber 42 is formed on the rear portion 36 . The rotary percussion drive 22 thus has a further shock absorber--in the form of the recoil damper 42--which is set up to dampen an impact of the percussion hammer 30 in a longitudinal percussion direction parallel to the longitudinal axis. The recoil damper 42 also contributes to the fact that unwanted vibrations can be reduced or avoided altogether.

The rotary percussion drive 22 of the impact wrench 10 also has a sliding damper 44 . The sliding damper 44 is formed on the drive shaft 28 on the peripheral side. Has a material with an increased coefficient of sliding friction relative to the adjacent drive shaft 28 . If the racquet 30 reaches the area of the sliding damper 44, for example due to a correspondingly high speed in the longitudinal direction LR, then the movement of the racquet 30 in the longitudinal direction LR will be due to the increased coefficient of friction of the sliding damper 44 braked. An impact of the racquet 30 along the longitudinal direction LR can also be avoided or at least reduced in this way, so that unwanted vibrations can also be avoided or at least reduced as a result.

The shock absorber 40 and/or the recoil absorber 42 can have a plastic and/or a rubber-containing material, for example rubber.

In the embodiment of the impact wrench 10 shown here, the shock absorbers 40, the recoil absorber 42 and the slide damper 44 are designed as passively acting elements. It is also conceivable that at least one of these elements 40, 42, 44 has at least one adjustable property, for example adjustable damping, an adjustable viscosity, for example electrically and/or magnetically, and/or an adjustable coefficient of friction. The element or elements with an adjustable property can be connected to a control unit of the impact wrench 10 . The control unit can be set up to set the adjustable property as a function of a position, a speed and/or an acceleration, in particular along the longitudinal direction L.

The embodiment of the impact wrench 10 shown here thus has a total of three shock absorbers, in particular the shock absorber 40, the recoil absorber 42 and the slide damper 44. In alternative embodiments it can be provided that only one or two of these shock absorbers or more than three shock absorbers are provided.

Reference List

10

impact wrench

12

Housing

14

tool holder

16

grip area

18

control element

20

battery pack

22

rotary percussion drive

24

Recording

25

engine

26

transmission

28

drive shaft

30

bat

32

anvil

36

Section

38

return spring

40

shock absorber

42

recoil absorber

44

sliding damper

II, III

Area

L

longitudinal axis

LR

longitudinal lay direction

u

circumferential direction

Claims (6)

Impact wrench (10) comprising a rotary impact drive (22), - wherein the rotary percussion drive (22) has a drive shaft (28) running along a longitudinal axis (L), wherein the rotary percussion drive (22) has a beater (30) arranged to be displaceable along the longitudinal axis (L) and an anvil (32) that can be contacted by the beater (30) along a circumferential direction (U) to the longitudinal axis (L), and - wherein the rotary percussion drive (22) has at least one shock absorber (40, 42, 44) which is set up to absorb an impact of the percussion (30) in a longitudinal percussion direction (LR) parallel to the longitudinal axis (L), in particular on the anvil (32) , to dampen. Impact wrench according to the preceding claim, characterized in that the shock absorber (40) is formed between the hammer (30) and the anvil (32). Impact wrench according to one of the preceding claims, characterized in that the shock absorber (42, 44) is formed between the hammer (30) and the drive shaft (28). Impact wrench according to one of the preceding claims, characterized in that a recoil absorber (42) between a rear side of the hammer (30) pointing counter to the longitudinal direction of impact (LR) and one opposite the anvil (32) counter to the longitudinal direction of impact (LR) causes a movement of the hammer (30) along the longitudinal axis (L) is formed delimiting the recoil surface. Impact wrench according to one of the preceding claims, characterized in that the shock absorber (40, 42, 44) comprises a plastic and/or a material containing latex, for example a material containing caoutchouc, in particular rubber. Impact wrench according to one of the preceding claims, characterized in that the shock absorber (40, 42, 44) has a fluid, in particular a liquid containing oil and/or water and/or a gas, in particular air.

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