EP3615269B1 - Machine tool with adjustable handle assembly - Google Patents

Description

The invention relates to a machine tool, in particular a hand-held machine tool, with a machine tool housing and a handle arrangement whose angular position can be adjusted relative to the machine tool housing. The handle arrangement contains at least one handle with at least one coupling means, which can be adjusted in its angular position relative to at least one counter-coupling means of the machine tool housing and can be moved linearly along a movement axis. Furthermore, the handle assembly holds a locking mechanism, which is designed to fix the handle in a coupled state, in which the coupling means of the handle is engaged with the counter-coupling means of the machine tool housing, so that the handle and the machine tool housing are firmly connected to each other, and in a release decoupled state, in which the coupling means of the handle is disengaged from the counter-coupling means of the machine tool housing, so that the handle is adjustable relative to the machine tool housing in its angular position. A generic machine tool is out DE 299 12 406 U1 known.

Machine tools of the type mentioned are known from the prior art. Machine tools, particularly hand-held machine tools such as a hand grinder, are typically provided with a rigid, rear guide handle near the on/off switch and an often moveable, partially detachable front handle. The front handle is usually in the form of a rod or a bow. In the bow-shaped embodiment, the front handle can usually be swiveled around the connection point to the machine tool housing in order to be able to adapt the ergonomics of the machine tool to different working conditions, such as grinding or cutting on a surface, in corners or niches, etc.

In most cases, the front handle is adjusted using a clamping screw that presses the front handle into a face gear. The clamping screw can be tightened with a toggle (similar to a "wing nut") or with a tool. The user must note that if the tensioning screw is not sufficiently pre-tensioned, the connection between the front handle and the machine tool housing can loosen. However, it is often not clear to the user when the clamping screw has been tightened sufficiently. A further complication is that the clamping forces that can be achieved without tools are limited. In addition, many turns of the clamping screw are annoying for the user, especially when the front handle has to be adjusted frequently.

It is the object of the present invention to provide a machine tool of the type mentioned at the outset which does not have or at least reduces the above-mentioned disadvantages of the hand-held machine tools known from the prior art. To solve the problem, the present invention proposes a machine tool according to claim 1.

In the machine tool according to the invention, the locking position of the eccentric lever is therefore assigned to the coupled state of the handle and the release position of the eccentric lever is assigned to the decoupled state of the handle. In other words, the functional states of the handle, ie its coupled or uncoupled state, are defined without a doubt by the two end positions of the eccentric lever, ie the locking and release position. The locking mechanism of the machine tool according to the invention can be adjusted within a few seconds without tools.

In order to move the eccentric lever from its locking position to its release position (or vice versa), the eccentric lever is pivoted about its pivot axis, which is eccentric to the center point of the cam contour of the eccentric lever. The association between the states of the eccentric lever and the handle is therefore via the at least one cam contour of the eccentric lever. If the eccentric lever is in its locking position, the coupling means of the handle and the counter-coupling means engage of the machine tool housing into one another, with the cam contour preventing the handle from shifting along the axis of movement. The handle and the machine tool housing are firmly connected. However, when the eccentric lever is in its release position, the cam contour allows the handle to slide along the axis of movement. The handle can then, for example, be moved manually along the axis of movement in order to detach the coupling means of the handle from the counter-coupling means of the machine tool housing.

Preferably, the coupling means of the handle and the counter-coupling means of the machine tool housing form face gearing.

In order to be able to adjust the clamping force acting on the handle and the force to be applied by the user when pivoting the eccentric lever, it is further preferred for the position of the stop to be adjustable along the movement axis.

According to a further preferred embodiment, the power tool housing has a dome, which extends along the movement axis, for attaching the handle arrangement. The dome can include a core hole, ie it can be in the form of a hollow cylinder and have an internal thread. In this case, the stop for the eccentric lever can be provided on an adjusting screw with an external thread, which is screwed into the internal thread of the hollow-cylindrical dome.

In the case of a handle connection on both sides, the adjusting screw can alternatively be extended to the opposite side of the machine tool housing and fixed at a second attachment point of the handle. As a further alternative, the dome in the machine tool housing can also be designed as an independent axle or sleeve that is connected to the opposite side of the handle.

According to a preferred embodiment, the adjusting screw is also in the form of a hollow cylinder and has an internal thread in addition to the external thread. In order to secure the adjusting screw in its axial position within the dome, a lock screw with an external thread can be screwed into the adjusting screw. The lock screw is preferably supported on the base of the core hole in the dome, in order to clamp the adjusting screw firmly in the core hole of the dome. This prevents the adjusting screw from loosening.

According to a further preferred embodiment, the eccentric lever has two legs which each provide a cam contour at the second end of the eccentric lever and have a pivot pin. In this case, the pivots or their centers define the pivot axis of the eccentric lever. In this way, the eccentric lever can grip the dome with the two legs, which favors a compact design.

In order to ensure the most compact possible construction of the handle arrangement, it can further be provided that the at least one bearing element is a bearing block which is arranged between the legs of the eccentric lever. Furthermore, the bearing block can have two support elements, each with a recess, the recesses accommodating the pivot pins of the eccentric lever. For reasons of simple assembly of the handle arrangement, the recesses can be essentially semicircular or U-shaped and can be slid onto the pivot pins.

The handle assembly may further include a cap that secures the eccentric lever and bearing block from rotating about the axis of movement relative to the handle. The eccentric lever and the bearing block can thus be arranged in a fixed position relative to the handle, but rotating with the handle. In this case, it is advantageous if the handle is shaped in such a way that the eccentric lever dips into the handle in its locking position, thereby preventing the eccentric lever from being accidentally pivoted out of the locking position into the release position. Alternatively, it is possible to design the eccentric lever to be stationary with respect to the machine tool housing or undefined on the machine tool housing.

The cap can also prevent incorrect manipulation of the adjustment screw secured with the counter screw.

When the eccentric lever pivots, the at least one cam contour slides along a movement path. In order to reduce wear in the area of the contact surface between the at least one cam contour and the handle, the handle can be provided with a thrust washer in this contact area.

Further advantages result 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 further meaningful combinations.

In the figures, the same and similar components are denoted by the same reference symbols.

Fig. 1A/B

eine bekannte handgeführte Werkzeugmaschine mit verstellbarem Handgriff;

Fig. 2

eine Griffanordnung an einer erfindungsgemäßen Werkzeugmaschine;

Fig. 3

die Griffanordnung der Fig. 2 in einer Explosionsdarstellung;

Fig. 4

die Griffanordnung der Fig. 2 in einer Schnittdarstellung;

Fig. 5

einen Handgriff in einer perspektivischen Ansicht;

Fig. 6

eine Nockenkontur in einer Draufsicht;

Fig. 7

einen Exzenterhebel, einen Lagerbock und eine Kappe im zusammengesetzten Zustand in einer perspektivischen Ansicht; und

Fig. 8

den Handgriff der Fig. 5 mit eingesetztem Exzenterhebel.

Show it:

Figure 1A/B

a known hand-held machine tool with an adjustable handle;

2

a handle assembly on a machine tool according to the invention;

3

the handle arrangement 2 in an exploded view;

4

the handle arrangement 2 in a sectional view;

figure 5

a handle in a perspective view;

6

a cam contour in a plan view;

7

an eccentric lever, a bearing block and a cap in the assembled state in a perspective view; and

8

the handle of figure 5 with inserted eccentric lever.

Example:

Figure 1A shows a hand-held machine tool known from the prior art in the form of a hand-held grinder SG. The well-known hand grinder SG comprises a housing G, at the rear end of which and in the vicinity of an on/off switch EAS a rear guide handle HG is arranged. The rear guide handle HG is rigid with the hand grinder SG. The hand grinder SG also includes a front handle VG, which has a bow-shaped shape. The front handle VG is arranged on the side of the hand grinder SG in such a way that it can be pivoted about a pivot axis and can be detached from the hand grinder SG if necessary ( Figure 1B ). In particular, the housing G includes a counter-coupling means GKM, which interacts with a coupling means KM on the handle VG. To adjust the position of the front handle VG, a clamping screw SP is loosened, then the front handle VG is pivoted into the desired position and finally the clamping screw SP is tightened again in order to press the coupling means KM on the handle VG back into the counter-coupling means GKM on the housing G. Due to the swiveling connection of the front handle VG to the hand grinder SG, the position of the front handle VG can be adjusted to different environmental conditions, for example grinding or cutting on the surface, in corners, niches, etc.

A machine tool 2 according to the invention is in 2 only implied. The machine tool 2 comprises a machine tool housing 4 and a handle arrangement 6 whose angular position can be adjusted relative to the machine tool housing 4. The machine tool housing 4 can be a gear housing, for example, and have a cylindrical shape at least in the area of the handle arrangement 6. The handle assembly 6 includes a locking mechanism 8 and a handle 10. The handle 10 of the handle assembly 6 has a hollow frustoconical base 12 and an elongated, L-shaped grip portion 14 which is molded onto the hollow frustoconical base 12.

As in the exploded view of the 3 to see, the machine tool housing 4 includes a hollow-cylindrical dome 16 with a core hole 18, which has an internal thread ( 4 ). The dome 16 protrudes from the machine tool housing 4 and extends along a movement axis X.

Out of 3 also shows that the base 12 of the handle 10 in the form of a truncated cone is formed by a casing wall 20 and a top wall 22 . In the assembled state of the handle assembly 6, the back of the top wall 22 of the handle 10 is the Machine tool housing 4 facing. The top wall 22 has an opening 24 for the dome 16 ( 4 ).

The back of the top wall 22 facing the power tool housing 4 in the assembled state has a handle-side coupling means 26 . As in figure 5 shown, the handle-side coupling means 26 is designed as a concentric ring to the opening 24 circumferential face gearing around the opening 24. Provided radially between the opening 24 and the coupling means 26 on the top wall 22 is a planar ring area 28 on the handle side, which is recessed relative to the coupling means 26 .

A counter-coupling means 30 on the housing side is provided concentrically to the dome 16 or to the movement axis X, which is designed as a counter-face toothing running annularly around the dome 16 ( 3 ). Arranged radially between the dome 16 and the counter-coupling means 30 is a planar annular area 32 on the housing side, which is recessed relative to the counter-coupling means 30 .

The locking mechanism 8 makes it possible to move the handle 10 between a state coupled to the machine tool housing 4 and a state decoupled from the machine tool housing 4 .

If the handle 10 and the machine tool housing 4 are in the coupled state, the counter-coupling means 30 of the machine tool housing 4 and the coupling means 26 of the handle 10 are engaged. The handle 10 is then firmly connected to the machine tool housing 4 and cannot move relative to the machine tool housing 4 .

If the handle 10 and the machine tool housing 4 are in the decoupled state, the counter-coupling means 30 of the machine tool housing 4 and the coupling means 26 of the handle 10 are disengaged. As a result, a relative movement between the handle 10 and the machine tool housing 4 is possible. In particular, the angular position of the handle 10 can be adjusted relative to the machine tool housing 4 by rotating the handle 10 about the axis of movement X. In order to fix the set angular position, the coupled state between the handle arrangement 6 and the machine tool housing 4 is restored by means of the locking mechanism 8 .

The locking mechanism 8 is described in more detail below.

In the exemplary embodiment shown, the locking mechanism 8 has a spring element 34, an eccentric lever 36, a bearing block 38 for the eccentric lever 36, a hollow-cylindrical adjusting screw 40 with an external thread (for example with Thread size M16) and an internal thread (for example with thread size M8), a lock screw 42 with an external thread and a cap 43 on.

In 3 it can be seen that the spring element 34 is arranged between the machine tool housing 4 and the handle 10 . More precisely, the annular depressions 28, 32 of the top wall 22 and the machine tool housing 4 form an annular channel when the handle arrangement 6 is in the assembled state ( 4 ), in which the spring element 34 is arranged in the form of a rectangular spring. The spring element 34 thus runs concentrically to the dome 16 and to the opening 24.

As in 3 also shown, the eccentric lever 36 has a first end 44 and a second end 46. At its first end 44, the eccentric lever 36 has an elongate eccentric grip 48, from which two fork-shaped, parallel legs 50 extend in the direction of the second end 46 of the eccentric lever 36 extend. In the mounted state of the handle arrangement 6, the legs 50 rest with their outsides on the inside of the lateral surface 12 of the handle 10 in order to prevent the eccentric lever 36 from rotating about the movement axis X relative to the handle 10 ( 2 ).

The eccentric lever 36 is between an in 2 locking position shown and a release position pivotable. As in 2 and 3 As can be seen, the handle 10 in the exemplary embodiment shown is shaped in such a way that the eccentric lever 36 dips into the L-shaped handle section 14 in its locking position.

The legs 50 each have an outwardly curved contour 52 at the second end 46, which is essentially semicircular in the exemplary embodiment shown. The center point 54 of the semicircular contour 52 is in 6 shown. In addition, a circular pivot pin 56 is arranged on the opposite inner surfaces of the legs 50 in each case. The center 58 of the pivots 56 is also in 6 implied. The center of circle 58 of each circular pivot 56 is at a distance D from the center of circle 54 of the corresponding curved contour 52 that is greater than zero. In this way, each semi-circular contour 52 forms a cam contour with respect to the circle center 58 of the corresponding pivot pin 56 . In other words, the axis defined by the centers 54 is eccentric to the axis defined by the centers 58 which forms the pivot axis S for the eccentric lever 36 .

As in 8 As can be seen, the legs 50 rest with their curved contours 52 in the assembled state on the front side of the top wall 22 of the handle 10 . This also defines the pivot axis S of the eccentric lever 36, which extends through the Midpoints 58 of the pivot pins 56 of the two legs 50 extends. For reasons of clarity, in 8 only the handle 10 and the eccentric lever 36 are shown in their locked position.

The bearing block 38 of the locking mechanism 8 has an annular base 60 with an opening 62 for the adjustment screw 40 and two opposing support elements 64 which extend substantially perpendicularly from the rear of the base 60 away. A semicircular or U-shaped recess 66 is provided at the end of the support elements 64 which is further away from the base 60 . In the assembled state, the pivot pins 56 of the legs 50 are accommodated in the recesses 66 of the support elements 64 . The support elements 64 point towards the top wall 22 and lie against the insides of the legs 50 .

Instead of recesses 66, bores for the pivot pins 56 can alternatively also be provided in the support elements 64.

The hollow cylindrical adjustment screw 40 of the locking mechanism 8 has an elongated body portion 68 and a head portion 70 through which a bore 72 extends. Between the body section 68 and the head section 70 there is an annular circumferential shoulder 74 on which the base 60 of the bearing block 38 rests when the handle arrangement 6 is in the assembled state. The body portion 68 of the adjustment screw 40 has external threads and internal threads. When the handle arrangement 6 is in the assembled state, the adjusting screw 40 is screwed with its external thread into the internal thread of the dome 16 . More precisely, when the handle arrangement 6 is in the assembled state, the adjusting screw 40 extends through the opening 62 in the base 60 of the bearing block 38, the opening 24 in the top wall 22 of the handle 10, the spring element 34 and finally through the dome 16 of the machine tool housing 4.

When mounting the handle arrangement 6 on the machine tool housing 4, the spring element 34, the handle 10, the eccentric lever 36 and the bearing block 38 are threaded onto the dome 16 of the machine tool housing 4 and screwed to the hollow-cylindrical adjusting screw 40. To secure the axial position of the adjusting screw 40 relative to the machine tool housing 4, the lock screw 42 is screwed into the bore 72 of the adjusting screw 40. The lock screw 42 can be a hexagon socket screw, for example. As in 4 As can be seen, the end of the lock screw 42 plunging into the bore 72 is supported against a shoulder 78 formed by the core hole 18 of the dome 16 in order to clamp the adjusting screw 40 firmly in the dome 16 .

In this way, a defined distance can be set between the shoulder 74 of the adjusting screw 40, which serves as a stop for the bearing block 38, and the counter-coupling means 30 of the machine tool housing 4. This in turn also defines a predetermined distance between the pivot axis S of the eccentric lever 48 and the counter-coupling means 30 of the machine tool housing 4.

In the illustrated embodiment, the handle assembly 6 also includes the cap 43. From 7 It can be seen that the cap 43 has an essentially rectangular base wall 82 , from the rear of which four walls extend essentially perpendicularly to the base wall 82 in the direction of the machine tool housing 4 . More specifically, two substantially parallel side walls 84 extend from the base wall 82, a bottom wall 86 substantially perpendicular to the side walls 84 and an arm 88 substantially parallel to the bottom wall 86. The side walls 84 are each provided with a recess at their end closer to the bottom wall 86 90 provided. On its side facing the bottom wall 86, the arm 88 has a latching device 92 in the form of a wedge-shaped projection.

In the mounted state of the handle arrangement 6, the cap 43 is accommodated between the legs 50 of the eccentric lever 36, the legs 50 of the eccentric lever 36 resting with their inner surfaces on the side walls 84 of the cap 43. As a result, the outer sides of the side walls 84 of the cap 43 serve to guide the legs 50 of the eccentric lever 36 during its pivoting movement from the locking position to the release position and vice versa. In addition, the cap 43 is supported with the base wall 86 on the lateral surface 12 of the handle 10 . This arrangement ensures that the cap 43 cannot rotate about the movement axis X relative to the handle 10 . The cap 43 is secured against axial displacement along the movement axis X away from the machine tool housing 4 in the assembled state of the handle arrangement 6 in that the eccentric handle 48 overlaps with the upper end of the base wall 82 of the cap 43 in the radial direction and in front of the upper end in the axial direction of the base wall 82 ( 2 ).

The bearing block 38 is arranged between the arm 88 and the bottom wall 86 . The locking device 92 of the arm 88 engages behind the base 60 of the bearing block 38 and the two support elements 64 of the bearing block 38 are accommodated in the recesses 90 of the cap 43 . this is in 7 shown. In this way, the bearing block 38 is secured relative to the cap 43 and thus also to the handle 10 both against rotation about the X axis of movement and against axial displacement along the X axis of movement.

The operation of the handle assembly 6 is as follows:
In the coupled state, the counter-coupling means 30 of the machine tool housing 4 engages with the coupling means 26 of the handle 10 against the action of the spring element 34 . The opposing force to the spring force is applied by the other components of the locking mechanism 8 . For this purpose, the distance between the adjusting screw 40 and the machine tool housing 4 or its counter-coupling means 30 is set in such a way that in 2 illustrated locking position of the eccentric lever 36, the cam contours 52 of the legs 50 press with a predefined compressive force against the top wall 22. As a result, the pivot pins 56 of the legs 50 are pressed against the bearing block 38 and this against the shoulder 74 of the adjusting screw 40. However, due to the anchoring of the adjusting screw 40 in the dome 16 of the machine tool housing 4 , the adjusting screw 40 can exert the corresponding counterforce on the bearing block 38 . Since the handle arrangement 6 is in equilibrium in the coupled state, ie it does not move, the pressure force caused by the eccentric lever 36 must be kept in balance by the spring force caused by the spring element 34 . Both the compressive force caused by the eccentric lever 36 and the spring force caused by the spring element 34 act on the top wall 22 of the handle 10, but in opposite directions and can therefore balance each other out.

If the eccentric lever 36 is brought from the locking position to the release position by pivoting the eccentric lever 36 in the direction away from the handle 10 about the pivot axis S, the curved contours 52 of the two legs 50 slide on the top wall 22. In particular, the distance between the Pivot axis S of the eccentric lever 36 and the points of contact of the curved contours 52 on the top wall 22. In this way, the compressive force caused by the eccentric lever 36 on the top wall 22 of the handle 10 is reduced, so that the spring element 34 can relax. The relaxation of the spring element 34 pushes the handle 10 away from the machine tool housing 4 , as a result of which the counter-coupling means 30 of the machine tool housing 4 disengages from the coupling means 26 of the handle 10 .

Reference List

2

machine tools

4

machine tool housing

6

handle arrangement

8th

locking mechanism

10

handle

12

Hollow truncated base

14

L-shaped handle section

16

Dom

X

motion axis

18

core hole

20

shell wall

22

ceiling wall

24

opening

26

Handle side coupling means

28

Ring area on handle side

30

Enclosure-side negative feedback means

32

Housing-side ring area

34

spring element

36

eccentric lever

S

pivot axis

38

bearing block

40

Cylindrical adjusting screw

42

lock screw

43

cap

44

First end of eccentric lever

46

Second end of eccentric lever

48

eccentric grip

50

Leg of the eccentric lever

52

Curved contour of a thigh

54

Center point of the curved contour of a leg

56

pivot

58

center of a pivot

D

Distance between centers 54 and 58

60

Ring-shaped base of the bearing block

62

Opening in the base of the pillow block

64

Supporting elements of the bearing block

66

Semi-circular recess in the support elements of the bearing block

68

Elongated body portion of the adjustment screw

70

Adjusting Screw Head Section

72

Adjusting screw hole

74

shoulder of the adjusting screw

78

Heel in the core hole of the dome

82

base wall of the cap

84

side walls of the cap

86

bottom wall of the cap

88

arm of the cap

90

recess

92

locking device

Claims (9)

1. Machine tool (2), in particular hand-held machine tool, having a machine-tool housing (4) and a handle assembly (6) that can be adjusted in terms of its angular position with respect to the machine-tool housing (4), wherein the handle assembly (6) includes:

   at least one handle (10) with at least one coupling means (26), which can be adjusted in terms of its angular position relative to at least one mating coupling means (30) of the machine-tool housing (4) and can be moved linearly along a movement axis (X), and

   a locking mechanism (8), which is designed to fix the handle (10) in a coupled state, in which the coupling means (26) of the handle (10) is in engagement with the mating coupling means (30) of the machine-tool housing (4), so that the handle (10) and the machine-tool housing (4) are firmly connected to each other, and to release the same in an uncoupled state, in which the coupling means (26) of the handle (10) is out of engagement with the mating coupling means (30) of the machine-tool housing (4), so that the handle (10) can be adjusted in terms of its angular position relative to the machine-tool housing (4),

   wherein the locking mechanism (8) includes:

   an eccentric lever (36) having a first end (44) and a second end (46), which can be pivoted reversibly between a locked position and a release position about a pivot axis (S) extending at right angles to the movement axis (X) and provided in the area of the second end (46),

   at least one bearing element (38) for pivotably supporting and holding the eccentric lever (36), and

   a stop (74) for the eccentric lever (36) for defining a predetermined distance between the pivot axis (S) and the mating coupling means (30) of the machine-tool housing (4),

   wherein at least one cam contour (52), the centre (54) of which is located outside the pivot axis (S), is provided at the second end (46) of the eccentric lever (36), so that the handle (10) is transferred into the coupled state by pivoting the eccentric lever (36) into the locked position and is released into the uncoupled state by pivoting the eccentric lever (36) into the release position,

   characterized in that the locking mechanism (8) further includes a spring element (34) which is arranged between the machine-tool housing (4) and the handle (10) and which transfers the handle (10) from the coupled state into the uncoupled state.
2. Machine tool (2) according to Claim 1,
   characterized in that the position of the stop (74) for the eccentric lever (36) is adjustable along the movement axis (X).
3. Machine tool (2) according to Claim 1 or 2,
   characterized in that the machine-tool housing (4) has a dome (16) extending along the movement axis (X) for the attachment of the handle assembly (6).
4. Machine-tool (2) according to Claim 3,
   characterized in that the dome (16) is hollow-cylindrical and has an internal thread, and in that the stop (74) for the eccentric lever (36) is provided on an adjusting screw (40) having an external thread, which is screwed into the internal thread of the hollow-cylindrical dome (16).
5. Machine tool (2) according to Claim 4,
   characterized in that the adjusting screw (40) is hollow-cylindrical and has an internal thread, wherein a locking screw (42) having an external thread is screwed into the adjusting screw (40) in order to secure the adjusting screw (40) axially.
6. Machine tool (2) according to one of the preceding claims,
   characterized in that the eccentric lever (36) has two limbs (50), which each provide a cam contour (52) at the second end (46) of the eccentric lever (36) and have a pivot pin (56), wherein the pivot pins (56) define the pivot axis (S) of the eccentric lever (36).
7. Machine tool (2) according to one of the preceding claims,
   characterized in that the at least one bearing element is a bearing block (38), which is arranged between the limbs (50) of the eccentric lever (36).
8. Machine tool (2) according to Claim 7,
   characterized in that the bearing block (38) has two supporting elements (64) each having a recess (66), wherein the recesses (66) receive the pivot pins (56) of the eccentric lever (36).
9. Machine tool (2) according to Claim 7 or 8,
   characterized in that the handle assembly (6) additionally includes a cap (43), which secures the eccentric lever (36) and the bearing block (38) against rotation about the movement axis (X) relative to the handle (10).

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