EP3900881A1 - Electric hand tool with ball locking coupling - Google Patents

Abstract

Electric hand tool, in particular hammer drill and / or chisel hammer, with a function control tube that can be operated via a manual function selector switch to bring about various operating modes, a guide tube equipped with a tool holder, and with a ball locking coupling for transferring a rotary movement from the function control tube to the guide tube, the Ball locking coupling has a radial opening formed in the function control tube, a main locking recess formed in the guide tube, a coupling ball mounted in the radial opening and intended to engage in the main locking recess, and a spring-loaded conical ring against whose actuating force the coupling ball can deflect in the radial direction, with one in the guide tube Additional recess different from the main notch recess is formed, the opening angle of which is greater than an opening angle of the main notch recess.

Description

The present invention relates to an electric hand tool, in particular a hammer drill and / or chisel hammer. The hand machine tool is equipped with a function control tube that can be actuated via a manual function selector switch. This means that different operating modes, such as chisel positioning, chiselling, hammer drilling and drilling without impact, can be set. The handheld power tool has a guide tube that is equipped with a tool holder, and a ball locking coupling for transmitting a rotary movement from the functional control tube to the guide tube. The ball locking coupling has a radial opening formed in the function control tube, a preferably groove-shaped main locking recess formed in the guide tube, a coupling ball mounted in the radial opening and intended to engage in the main locking recess, and a spring-loaded conical ring. The coupling ball can deflect against an actuating force of the spring-loaded conical ring in the radial direction, based on the guide tube. If a tool received in the tool holder jams, the guide tube comes to a standstill. The function control tube, on the other hand, continues to be driven, for example in the hammer drilling operating mode. When the torque applied by the guide tube overcomes the actuating force of the spring-loaded conical ring, the coupling ball emerges from the main notch recess and is moved in the circumferential direction along the guide tube. In this way, damage to one or more transmission components of the handheld power tool can be prevented. If the torque applied by the guide tube falls below the actuating force of the spring-loaded conical ring, the coupling ball is pushed back into the main notch recess by the conical ring.

Hand machine tools of the type mentioned at the outset are basically known from the prior art.

The object of the present invention is to provide a handheld power tool that can be operated particularly reliably.

The object is achieved in that an additional recess different from the main notch recess is formed in the guide tube, the opening angle of which is greater than an opening angle of the main notch recess. A respective opening angle is preferably in a radial section plane of the guide tube. The radial section plane of the guide tube is preferably a section plane whose normal to the surface runs parallel, preferably coaxially, to the working axis (longitudinal axis) of the guide tube. It has been found to be advantageous if the opening angle of the main notch recess is between 70 degrees and 80 degrees, preferably 75 degrees. In a particularly preferred embodiment, the opening angle of the additional recess is greater than 90 degrees, preferably greater than 120 degrees.

The invention includes the knowledge that there are situations in which a coupling ball that has been moved out of the main notch recess, i. H. after a safety stop of the ball locking clutch does not return to its intended position in the main locking recess, but rather comes to a standstill on a non-recessed surface of the guide tube. In this case, a radial force between the guide tube and the coupling ball is so great that the function adjusting tube can no longer be adjusted axially to effect the various operating modes of the handheld power tools. The additional recess provided according to the invention with a larger opening angle provides a defined position of the coupling ball on the surface of the guide tube, so that the functional control tube can be moved in the axial direction at any time.

It has been found to be advantageous if the additional recess is longer in the axial direction than the main notch recess. In a particularly preferred embodiment, the main notch recess and the additional recess are spaced apart from one another in the circumferential direction, based on the guide tube, by a web. It has been found to be advantageous if a web width of the web in the circumferential direction is less than 1 mm. The web width can be less than 0.5 mm. In a particularly preferred embodiment, the web width is 0.4 mm.

It has been found to be advantageous if an opening width of the additional recess related to a circumferential circle of the guide tube is larger than an opening width of the main notch recess related to the circumferential circle. The circumferential circle of the guide tube is preferably to be understood as a circle which runs along an outer surface of the guide tube and is tangent to all of the webs of the guide tube. The opening width of the main notch recess is preferably the arc length of the part of the circumference that spans the main notch recess. The opening width of the additional depression is preferably the arc length of the part of the circumferential circle spanning the additional depression.

In a particularly preferred embodiment, the main notch recess and / or the additional recess are groove-shaped, preferably with a longer extension in the axial direction of the guide tube. A groove-shaped in particular The main notch recess can have a variable radius of curvature in the radial sectional plane and / or a flank section that is straight in sections. If this is the case, the opening angle of the main notch recess is preferably predetermined by that flank section of the main notch recess which has the longest extension in the radial direction. Alternatively, if the main notch depression, which is in particular groove-shaped, has a constant radius of curvature in the radial sectional plane, the opening angle of the main notch depression is preferably spanned by those secants which on the one hand touch the web and which intersect at the base of the main notch depression on the other.

An additional recess, in particular embodied in the form of a groove, can have a constant radius of curvature in the radial sectional plane. In this case, the opening angle of the main notch recess is preferably spanned by those secants which on the one hand touch the web and on the other hand intersect at the base of the main notch recess. Alternatively, an additional recess, in particular embodied in the form of a groove, can have a variable radius of curvature in the radial sectional plane and / or straight flanks in sections. In this case, the opening angle of the additional depression is preferably spanned by those secants which on the one hand touch the web and on the other hand intersect at the base of the additional depression. In a particularly preferred embodiment, several main notch recesses and several additional recesses are provided on the guide tube. It has been found to be advantageous if the main detent depressions and the additional depressions alternate along the circumferential direction of the guide tube.

It has been found to be advantageous if the conical ring has a first conical shoulder and a second conical shoulder that is different from the first conical shoulder. Particularly preferably, the first conical shoulder and the second conical shoulder have different angles of inclination with respect to the axial direction. It has been found to be advantageous if the first conical shoulder, namely that conical shoulder which extends further away from the guide tube in the radial direction, has an angle of inclination between 50 degrees and 60 degrees, preferably 55 degrees. The second conical shoulder preferably has an angle of inclination between 35 degrees and 45 degrees, preferably 38 degrees. In a further preferred embodiment, the radial opening in the functional adjusting tube has a cylindrical passage and / or a conical bevel. The conical bevel particularly preferably has a cone angle between 15 degrees and 25 degrees, preferably 20 degrees, the cone angle being related to the radial direction.

In a particularly preferred embodiment, the electric handheld power tool is designed as a battery-operated combination hammer. The maximum working torque that can be transmitted via the ball locking coupling (the coupling balls are paired with the main locking depressions) is preferably between 30 and 40 Newton meters. An axial force to be applied for an axial displacement of the functional adjusting tube is preferably between 30 and 100 Newtons, in particular between 35 and 45 Newtons. A torque required to overcome the additional depressions (the coupling balls are paired with the additional depression) is preferably at most 50 percent, particularly preferably at most 20 percent of the maximum working torque that can be transmitted via the ball locking clutch.

The invention is also achieved by a guide tube for an electric hand tool, in particular for a hammer drill and / or chisel hammer, the guide tube having a main notch recess for at least partial engagement of a coupling ball and an inner volume for receiving an exciter piston of an impact mechanism. An additional recess different from the main notch recess is formed in the guide tube, the opening angle of which is greater than an opening angle of the main notch recess. The guide tube according to the invention can be configured in a corresponding manner by the exemplary embodiments described with reference to the electric hand tool.

Fig. 1A

ein erstes Ausführungsbeispiel einer erfindungsgemäßen Handwerkzeugmaschine;

Fig. 1B

eine Schnittansicht durch die Handwerkzeugmaschine;

Fig: 2A

ein Führungsrohr in Seitenansicht mit eingezeichneter Schnittlinie A-A gemäß einem ersten bevorzugten Ausführungsbeispiel;

Fig. 2B

eine Schnittansicht A-A (Radialschnittebene) aus Fig. 2A;

Fig. 3A

ein Führungsrohr in Seitenansicht mit eingezeichneter Schnittlinie A-A gemäß einem zweiten bevorzugten Ausführungsbeispiel;

Fig. 3B

eine Schnittansicht A-A (Radialschnittebene) aus Fig. 3A;

Fig. 4A

ein bevorzugtes Ausführungsbeispiels einer Kugelrastkupplung;

Fig. 4B

einen radialen Durchbruch in dem Funktionsstellrohr;

Fig. 4C

einen Kegelring mit einer ersten und zweiten Kegelschulter; und

Fig. 5

die Handwerkzeugmaschine der Figur 1 in einem anderen Betriebsmodus.

Further advantages emerge from the following description of the figures. Various exemplary embodiments of the present invention are shown in the figures. The figures, 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. In the figures, the same and similar components are numbered with the same reference numerals. Show it:

Figure 1A

a first embodiment of a handheld power tool according to the invention;

Figure 1B

a sectional view through the hand machine tool;

Fig: 2A

a guide tube in side view with the drawn section line AA according to a first preferred embodiment;

Figure 2B

a sectional view AA (radial sectional plane) Figure 2A ;

Figure 3A

a guide tube in side view with the drawn section line AA according to a second preferred embodiment;

Figure 3B

a sectional view AA (radial sectional plane) Figure 3A ;

Figure 4A

a preferred embodiment of a ball locking clutch;

Figure 4B

a radial opening in the function adjusting tube;

Figure 4C

a tapered ring having first and second tapered shoulders; and

Fig. 5

the hand tool of the Figure 1 in another operating mode.

Embodiments:

A first preferred exemplary embodiment of an electric handheld power tool 100 according to the invention is shown in FIG Figure 1A shown. The handheld power tool 100 is designed, for example, as a combination hammer. The handheld power tool 100 is equipped with a manual function selector switch 10 via which various operating modes of the handheld power tools 100 can be set. So shows Figure 1B by way of example, a section through the handheld power tool 100 in the hammer drilling BH operating mode, whereas Figure 5 shows, by way of example, a section through the handheld power tool 100 in the chiselling ME operating mode.

The electric hand machine tool 100 is equipped with a cylindrical guide tube 30 that has a tool holder 35. In the tool holder 35, a chisel 36 is received, which in Figure 1B is only shown in sections. The hand-held power tool 100 has a function control tube 10 that can be moved in the axial direction AR via the said manual function selector switch 20 to effect different operating modes. The cylindrical function control tube 10 is arranged coaxially to the guide tube 30.

The handheld power tool 100 is also equipped with a pneumatic hammer mechanism 50 which has an exciter piston 51 which is movable in the axial direction AR along a working axis AX within the guide tube 30. The exciter piston 51 is coupled via a connecting rod 53 to a striking mechanism eccentric wheel 55, which is driven by an electric motor, not shown here. By means of the exciter piston 51, a periodic impact mechanism pressure can be generated within the guide tube 30, since in the Figure 1B Hammer drilling BH operating mode shown, a vent opening 31 of the guide tube 30 is closed by the function control tube 20.

Both the function control tube 20 and the guide tube 30 are rotatably mounted about the working axis AX in a housing 90 of the handheld power tool 100. In order to set the function control tube 20 into rotation about the working axis AX, the handheld power tool 100 has a bevel pinion 23, which can be driven by the electric motor, not shown here. The bevel pinion 23 in turn drives a bevel ring 25 with which the function adjusting tube 20 - at least in the case of in Figure 1 Hammer drilling BH operating mode shown - is positively engaged in the circumferential direction UR.

The handheld power tool 100 furthermore has a ball locking coupling 40 for transmitting the rotary movement from the functional adjusting tube 20 to the guide tube 30. This is the Ball locking coupling 40 is equipped with a radial opening 42 formed in the function adjusting tube 20. The ball locking coupling 40 also has a coupling ball 45 mounted in the radial opening 42. The coupling ball 45 is intended to engage in a main notch recess 43 which is formed in the guide tube 30. If the coupling ball 45 is in engagement with the main notch recess 43, a rotary movement can be transmitted from the functional adjusting tube 20 to the guide tube 30. In the exemplary embodiment shown here, the guide tube 30 has a plurality of main notch depressions 43 which are formed on the guide tube 30 in the circumferential direction UR. Accordingly, a plurality of coupling balls 45 and, as it were, a plurality of radial openings 42 are also provided. The ball latching coupling 40 has a conical ring 47 which is spring-loaded by means of the spring 48 and against the actuating force AF of which the coupling balls 45 can deflect outward in the radial direction RR.

Figure 2 FIG. 3 shows a first preferred exemplary embodiment of a guide tube 30. The guide tube 30 is intended for an electric handheld power tool from FIG. 100 (see FIG Figure 1 ). It shows Figure 2A the guide tube 30 in a side view with the drawn section line AA. Section AA (radial section plane) is in Figure 2B shown. The guide tube 30 has six main notch recesses 43 which are arranged on the guide tube 30 in the circumferential direction UR. Alternating with the main notch recesses 43, six additional recesses 44 are formed in the guide tube 30.

Again Figure 2B can be removed, the groove-shaped main notch recess 43 does not have a constant radius of curvature in the radial section plane AA. The opening angle W1 of the main notch recess 43 is predetermined by that flank section 43 'of the main notch recess 43 which has the longest extension in the radial direction RR. The opening angle W1 of the main notch recess 43 is, for example, 75 degrees. Like that too Figure 2B can be removed, the groove-shaped additional recess 44 has a constant radius of curvature KR. An opening angle W2 of the additional recess 44 is spanned in the radial section plane AA by those secants SK which on the one hand touch the web 46 and on the other hand intersect at the base (the "lowest" point) of the additional recess 43. The opening angle W2 of the additional recess 44 is designed, for example, to be 135 degrees. Thus, the opening angle W2 of the additional recess 44 is larger than the opening angle W1 of the main notch recess 43. Due to the comparatively smaller opening angle W1 of the main notch recess 43, the main notch recess 43 is used to actually transmit a working torque from the function adjusting tube 20 (see Fig Figure 1B ) on the guide tube 30. The additional recess 44 is only intended to offer the coupling ball 45 a defined position along the circumferential direction UR of the guide tube 30, so that - regardless of the rotational position of the guide tube 30 - a displacement of the function control tube 20 in the axial direction AR is possible.

Like that too Figure 2 The additional recess 44 has an additional detent length LZ in the axial direction AR, which is greater than a main detent length LH of the main detent recess 43. For example, the web 46 has a thickness of 0.4 mm in the circumferential direction UR. It becomes clear that due to the small web thickness of the web 46, the coupling ball 45 (in Figure 2 not shown) either in the main notch recess 43 or the additional recess 44 comes to rest.

Figure 2B shows that an opening width OW2 of the additional recess 44 related to a circumferential circle UK of the guide tube 30 is larger than an opening width OW1 of the main notch recess 43 related to the circumferential circle UK. The circumferential circle UK of the guide tube 30 is that circle which is tangent to all webs 46 of the guide tube . The opening width OW1 of the main notch recess 43 corresponds to the arc length of the part UK1 of the circumferential circle UK spanning the main notch recess 43. The opening width of the additional depression OW corresponds to the arc length of the part UK2 of the circumferential circle UK spanning the additional depression 44.

Figure 3 shows a second preferred exemplary embodiment of a guide tube 30. The guide tube 30 is intended for an electric handheld power tool from FIG. 100 (see FIG Figure 1 ). It shows Figure 3A the guide tube 30 in a side view with the drawn section line AA. Section AA (radial section plane) is in Figure 3B shown. The guide tube 30 has six main notch recesses 43 which are arranged on the guide tube 30 in the circumferential direction UR. Alternating with the main notch recesses 43, six additional recesses 44 are formed in the guide tube 30.

The main notch recesses 43 of the embodiment of Figure 3 are identical to the main notch recesses 43 of the embodiment of FIG Figure 2 educated. Correspondingly, the opening angle W1 of the main notch recess 43 is predetermined by that flank section 43 'of the main notch recess 43 which has the longest extension in the radial direction RR. In contrast to the embodiment of Figure 2 is the additional recess 44 of the guide tube 30 of the Figure 3 stepped, ie in particular the additional recess 44 has two at least partially straight flanks 44 'and thus no constant radius of curvature. The opening angle W2 of the additional recess 44 is determined by the two at least in sections straight flanks 44 'spanned. The opening angle W2 of the additional recess 44 is designed, for example, to be 135 degrees. Thus, the opening angle W2 of the additional recess 44 is greater than the opening angle W1 of the main notch recess 43.

A preferred embodiment of a ball lock coupling 40 is shown in FIG Figure 4A shown. The ball locking coupling 40 serves to transfer the rotary movement from the functional adjusting tube 20 to the guide tube 30. For this purpose, the ball locking coupling 40 is equipped with a radial opening 42 formed in the functional adjusting tube 20. The ball locking coupling 40 also has a coupling ball 45 mounted in the radial opening 42. The coupling ball 45 is intended to engage in a main notch recess 43 which is formed in the guide tube 30. The ball locking coupling 40 has a conical ring 47 spring-loaded by means of the spring 48, against the actuating force AF of which the coupling ball 45 moves outwards in the radial direction RR (in Figure 4 up) can evade.

Again Figure 4B can be removed, the radial opening 42, which is located in the function adjusting tube 20 (cf. Figure 4A ) is formed, a cylindrical passage 42 'which is oriented coaxially to the radial direction RR. On the side of the radial opening 42 'facing away from the guide tube 30, a conical bevel 42 ″ is formed which has, for example, a cone angle KW of 20 degrees with respect to the radial direction RR. This conical bevel 42 ″ makes it easier for the coupling ball 45 to emerge in the radial direction outward (compare Figure 4A , Movement of the coupling ball 45 upwards).

the Figure 4C now shows a preferred embodiment of the spring-loaded conical ring 47. The conical ring 47 has a first conical shoulder 47a and a second conical shoulder 47b. The first conical shoulder 47a and the second conical shoulder 47b have different angles of inclination N1, N2 with respect to the axial direction AR. The first conical shoulder 47a, namely that conical shoulder which extends further away from the guide tube 30 in the radial direction RR, has, for example, an inclination angle N1 of 55 degrees. The second conical shoulder 47b has, for example, an inclination angle N2 of 38 degrees. Due to the design of the spring-loaded conical ring 47 with the first conical shoulder 47a and the second conical shoulder 47b - in combination with the conical bevel 42 ″, the movement of the functional adjusting tube 20 can be significantly reduced Ball locking coupling 45 realized release torque only minimally reduced.

Figure 5 finally shows the handheld power tool 100 of FIG Figure 1 in the chiselling ME operating mode. The hand machine tools 100 of the Figure 5 is also equipped with a pneumatic hammer mechanism 50, which has an exciter piston 51 which is movable in the axial direction AR along a working axis AX within the guide tube 30. The exciter piston 51 is coupled via a connecting rod 53 to a striking mechanism eccentric wheel 55, which is driven by an electric motor, not shown here. By means of the exciter piston 51, a periodic impact mechanism pressure can be generated within the guide tube 30, since in the Figure 1B Chiseling ME operating mode shown, a vent opening 31 of the guide tube 30 is closed by the function control tube 20.

Both the function control tube 20 and the guide tube 30 are rotatably mounted about the working axis AX in a housing 90 of the handheld power tool 100. In the chiselling ME operating mode, a rotation of the guide tube 30 is not desired. Correspondingly, in the chiseling ME operating mode, the function control tube 20 is not driven to rotate about the working axis AX. Although the bevel pinion 23 drives the already Figure 1B known conical ring 25 continues, but this is not with the functional adjusting tube 20 - based on the circumferential direction UR - in positive engagement. This, since the function control tube 20, is brought about by the function selector switch 10 (cf. Figure 1A ) in the direction of the tool holder 35 (in Figure 5 to the left) and a spur toothing 27 of the function adjusting tube 27 is spaced from the conical ring 25.

List of reference symbols

10

Function selector switch

20th

Function control tube

23

Bevel pinion

25th

Conical wreath

27

Spur gearing

30th

Guide tube

31

Vent

35

Tool holder

36

chisel

40

Ball locking coupling

42

radial breakthrough

42 '

cylindrical passage

42 "

Bevel

43

Main recess

43 '

Flank section

44

Additional specialization

44 '

Flanks

45

Coupling ball

46

web

47

Conical ring

47a

first cone shoulder

47b

second cone shoulder

48

Compression spring

50

Percussion

51

Exciter piston

53

Connecting rod

55

Impact mechanism eccentric wheel

90

casing

100

Electric hand machine tool

AF

Actuating force

AR

axial direction

AX

Working axis

bra

Hammer drilling operating mode

FP

Base point

KW

Cone angle

KR

Radius of curvature

LH

Main grid length

LZ

Additional rest length

ME

Chiseling operating mode

N1

Angle of inclination of the first tapered shoulder

N2

Angle of inclination of the second tapered shoulder

OW1

Opening width of the main recess

OW2

Opening width of the additional recess

RR

radial direction

SK

secant

UK

Circumference

UK1

Proportion of the circumference above the main recess

UK2

Proportion of the circumference above the additional specialization

UR

Circumferential direction

W1

Opening angle of the main notch recess

W2

Opening angle of the additional recess

Claims (11)

Electric hand tool (100), in particular a hammer drill and / or chisel hammer, with a function control tube (10) which can be actuated via a manual function selector switch (20) to effect different operating modes (ME, BH), a guide tube (35) equipped with a tool holder (35) 30), and with a ball locking coupling (40) for transmitting a rotary movement from the functional adjusting tube (20) to the guide tube (30), the ball locking coupling (40) having a radial opening (42) formed in the functional adjusting tube (20), one in the guide tube ( 30) has a main detent recess (43), a coupling ball (45) mounted in the radial opening (42) and intended to engage in the main detent recess (43), as well as a spring-loaded conical ring (47), against whose actuating force (AF) the coupling ball ( 45) can evade in the radial direction (RR),
characterized in that an additional recess (44) different from the main notch recess (43) is formed in the guide tube (30), the opening angle (W2) of which is greater than an opening angle (W1) of the main notch recess (43). Hand machine tool (100) according to Claim 1,
characterized in that the opening angle (W1) of the main notch recess (43) is between 70 degrees and 80 degrees, preferably 75 degrees and / or that the opening angle (W2) of the additional recess (44) is greater than 90 degrees, preferably greater than 120 degrees . Hand machine tool (100) according to Claim 1 or 2,
characterized in that the additional recess (44) is longer in the axial direction (AR) than the main notch recess (43). Hand machine tool (100) according to one of the preceding claims,
characterized in that the main notch recess (43) and / or the additional recess (44) are groove-shaped in the axial direction (AR). Hand machine tool (100) according to one of the preceding claims,
characterized in that an opening width (OW2) of the additional recess (44) related to a circumferential circle (UK) of the guide tube (30) is greater than an opening width (OW1) of the main notch recess (43) related to the circumferential circle (UK). Hand machine tool (100) according to one of the preceding claims,
characterized in that the main notch recess (43) and the additional recess (44) are spaced apart in the circumferential direction (UR) of the guide tube (30) by a web (46), the web (46) preferably having a web width of less than 1 millimeter. Hand machine tool (100) according to one of the preceding claims,
characterized in that the conical ring (47) has a first conical shoulder (47a) and a second conical shoulder (47b) which have different angles of inclination (N1, N2) with respect to the axial direction (AR). Hand machine tool (100) according to one of the preceding claims,
characterized in that the radial opening (42) has a cylindrical passage (42 ') with a conical bevel (42 ") which preferably has a cone angle (KW) of 20 degrees. Hand machine tool (100) according to one of the preceding claims,
characterized in that the radial opening (42) has a cylindrical passage (42 ') with a conical bevel (42 ") which is preferably 20 degrees. Hand machine tool (100) according to one of the preceding claims,
characterized in that several main notch recesses (43) and several additional recesses (44) are provided, which alternate along the circumferential direction (UR) of the guide tube (30). Guide tube (30) for an electric hand tool (100), in particular a hammer drill and / or chisel hammer, the guide tube having a main notch recess (43) for at least partial engagement of a coupling ball (45) and an inner volume for receiving an exciter piston (51) of an impact mechanism (50) has,
characterized in that an additional recess (44) different from the main notch recess (43) is formed in the guide tube (30), the opening angle (W2) of which is greater than an opening angle (W1) of the main notch recess (43).

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