EP1800803B1 - Hand tool with a ratchet striking mechanism - Google Patents

Description

The invention relates to an electric hand tool with a main housing, in particular made of plastic, in shell construction and a rotatably connected to a tool holder and emerging from the main housing at a tool end tool spindle. The tool spindle is rotatably driven about a motor and a gear, which are housed in the main housing, around a working axis around. In addition, the tool spindle can be acted upon by a ratchet impactor along the working axis with pulse-like axial movements. For this purpose, the ratchet impactor on a housing-fixed sprocket, which is connected to a supporting body on the main body. The housing-fixed ring gear acts together with a rotatably coupled to the tool spindle movable sprocket, wherein the support body is supported by support means in a direction away from the tool-side end direction.

The support means are circumferentially formed on an inner surface of an outer shell of the main body and the support body is directly adjacent to the Abstützmittelnan.

In such hand tool devices, a rotational movement of the tool spindle, which is used for a drilling or screwing, be additionally superimposed with an axial reciprocating motion, thereby increasing the Bohrvortrieb or Eindrehgeschwindigkeit, for example, self-tapping screws. The aforementioned ratchet impactor is used in particular for smaller power tools, such as screwdrivers with additional impact function or impact drills for use. Such tool devices often have a main housing in shell construction made of plastic, which is composed essentially of two longitudinally extending to the working axis shells, which lie in a customary orientation of the power tool with downwardly directed handle, via a joint to each other, which is substantially along extending parallel to the working axis vertical plane.

Here, all essential functional elements of the power tool can be preassembled in a half-shell and then by fastening the second half-shell be definitively secured, which significantly simplifies the installation, for example, compared to devices in pot construction, overall and reduces manufacturing costs.

DE 42 36 819 A1 shows a motor-driven rotary tool with a spindle which is axially reciprocally movable by a striker. The impact device has a movable cam element which is attached to the spindle. This movable cam member cooperates with a fixed cam member formed on a cam disc. The cam plate is supported in the axial direction away from a chuck with the interposition of a steel plate on an inner housing, which encloses a gear.

When pressing the known rotary tool against a surface to be machined, the power flow takes place here by the hand of the operator via a grip area on the main housing to the inner housing and from there via the steel plate to the fixed cam element. From this, the movable cam member presses during rotation of the spindle recurrently, whereby the axially striking reciprocating motion of the spindle is generated.

In particular, between the main housing and the relatively widely spaced supporting part of the inner housing, this results in impact energy losses due to relative movements of the two housing parts to each other as a result of deformation. As a result, the work performance, in particular compared to devices in pot construction, reduce, which also have transverse to the working axis continuous main housing sections which support the support body axially to the rear. Such a tool device in pot construction is, for example DE 1 204 126 C2 refer to.

In addition, such a tool device in shell construction, which is usually carried out with a plastic housing to keep the weight low, relatively prone to forces acting transversely to the working axis of the outside of the housing. Thus, for example, the attachment of a side handle by means of a clamping band, which is tightened around the housing around, lead to the same deformation. By these deformations devices of the power tool, such as the transmission, a torque coupling or a to / shutdown of the beater, in turn, can be disturbed in their function or completely blocked.

From the JP 59 182008 A Known as the closest prior art with respect to the subject matter of claim 1, a vibratory drilling machine is known which comprises vibrating plates between which two springs are arranged. One end of the springs is respectively in communication with a bottom surface of a vibration case connected to a first vibration plate. The other end of the one spring is brought into contact with a portion of the second vibrating plate The other end of the other spring, which is shorter than the first spring, in the initial state, however, has a distance from the second vibrating plate.

From the US 6,202,759 Further, a switching device for a power tool is known, comprising a housing, a rotatable collar, an output spindle, a fixed toothed disc and a movable toothed disc. By rotating the rotatable collar, the output spindle can be retracted into the housing to bring the movable toothed disc into contact with the fixed toothed disc. About the rotatable collar, the switching device can therefore the output spindle between a first position in which this only rotates and a position in which this rotates and beats are switched.

The present invention has for its object to avoid the disadvantages mentioned in a hand tool in shell construction and to increase the labor and stability.

According to the invention, the object is achieved in that the support body has a sleeve-shaped base body from which a plurality of support arms protrude radially, which form the radial contact surface at their free ends. In this way, at the same time a large part of the support body can be positioned in the axial direction of the ring gear with stable radial support action of the support arms. The plurality of support arms are arranged on a side facing away from the test sprocket and the tool holder side of the body. In this way, the mass of the support body region can be increased, which is the primary supporting effect, which in turn increases the performance of the tool device. It is achieved a direct power flow from the main body to the support body with the housing-fixed ring gear held thereon, whereby the impact energy losses significantly reduced and thus the performance of the hand tool can be increased. The peripherally arranged support means provide for a particularly stable support in the working direction, which can be used as a circumferential arrangement, both a continuous circumferential as well as an interrupted circumferential arrangement use.

Advantageously, the support body forms a radial contact surface, which rests circumferentially on the outer shell in the radial direction. In this way, the support body supports the main housing from the inside and thus causes a higher stability, especially against directed transversely to the working axis external loads of the main housing.

In a particularly preferred embodiment, the radial contact surface bears against the inner surface of the outer shell at the axial height of a cylindrical outer surface of the outer shell. In this way, the support body stabilize the main housing exactly where a side handle with the aid of a clamping band is clamped. In this way, a dysfunctional or even the main body damaging deformation can be prevented.

Advantageously, the support body is made of metal, whereby on the one hand a stable radial support is achieved and the housing-fixed sprocket axially supported on a particularly large mass, which further increases the working line of the power tool.

Furthermore, the support body is advantageously held on a transmission housing. As a result, on the one hand, the transmission housing can be stabilized by means of the support body. On the other hand, this assembly can be simplified.

It is particularly advantageous if the support body is cast in the gear housing. As a result, the required space can be reduced. Furthermore, both elements are handled together, which further simplifies the assembly. In addition, the gear housing is clearly stabilized in this way.

It is advantageous if a spindle bearing is pressed into the support body. As a result, the two sprockets of the ratchet impact can be positioned particularly accurately to each other, whereby their wear is reduced.

Advantageously, bearing recesses for guiding slip clutch means are embedded in the support body, whereby the support body assumes a further function and thus the number of individual elements of the tool device is further reduced, which in turn facilitates the assembly.

Fig. 1

eine Seitenansicht eines erfindungsgemässen Handwerkzeuggerätes,

Fig. 2

eine teilweise geschnittene Ansicht eines vorderen Teils des Handwerkzeuggerätes nach Fig. 1 mit entfernter Gehäusehalbschale,

Fig. 3

eine Seitenansicht eines Zahnkranzes des Handwerkzeuggerätes nach Fig. 2 an einem Stützköper und

Fig. 4

eine Rückansicht auf den Stützkörper in Richtung IV aus Fig. 3.

The invention will be explained in more detail below with reference to an embodiment. Show it:

Fig. 1

a side view of an inventive hand tool,

Fig. 2

a partially sectioned view of a front part of the power tool after Fig. 1 with removed housing half shell,

Fig. 3

a side view of a sprocket of the power tool after Fig. 2 on a supporting body and

Fig. 4

a rear view of the support body in the direction of IV Fig. 3 ,

Fig. 1 shows a hand tool 2 in the form of a battery-operated screwdriver with Axialschlagfunktion. This has a two-part main housing 4 in shell construction, which forms a contact surface 8 at a rear end 6 and projects from the side of a pistol-like handle 10. In the main housing 4, a motor 12 is housed, which rotatably drives a tool spindle 14 via a gear 16 about a working axis A around.

The tool spindle 14 protrudes out of the main housing 4 at a tool-side end 18 in a working direction R and is non-rotatably connected at the free end to a tool holder 20 in the form of a chuck. The tool spindle 14 penetrates a between the main housing 4 and tool holder 20 rotatably held adjusting sleeve 21 for setting a maximum torque.

Further, a side handle 22 is provided on the hand tool 2, which is clamped by a clamping band 24 to the main body 4 fixed.

Fig. 2 shows the tool-side end 18 of the power tool 2 in the open state, ie with respect to the working direction R left housing half shell 26 of the two-part main housing 4 is removed from a right housing half-shell 28, as indicated by the dismantling arrows D.

When the left housing half-shell 26 rests in the final assembled state on a parallel to the handle 10 abutting surface 30 of the right housing half-shell 28 and both housing half shells 26, 28 are bolted together via screw mandrels 32, they together form an outwardly closed outer shell 34. In this is in turn a cylindrical Formed outer surface 36, to which the clamping band 24 of the side handle 22 can be fixed.

Furthermore, in Fig. 2 a ratchet impact mechanism 38 shown having a non-rotatably connected to the tool spindle 14 movable ratchet ring 40 with a movable sprocket 41. The movable ring gear 41 acts in the operation of the ratchet impact mechanism 38 together with a fixed ring gear 43 of a fixed ratchet ring 42 which is welded to a metallic support body 44. This support body 44 is in turn cast in a gear housing 46 made of plastic, in which the gear 16 is received and which is used in the assembly of the hand tool 2 in the main housing 4.

As in particular from the Fig. 3 and 4 can be seen, the support body 44 has a sleeve-shaped base body 48 which is frontally connected to the housing-fixed ratchet ring 42 and in which, as in Fig. 2 shown, a spindle bearing 49 can be pressed. On a side facing away from the fixed ring gear 42 side of the base body 48 is widened and has star-shaped, radially projecting support arms 50. These support arms 50 form with their free ends an interrupted circumferential radial contact surface 52.

Furthermore, a bearing recess 54 in the form of an axially continuous bore is provided on each support arm 50.

As in Fig. 2 represented, at the axial height of the outer surface 36 on an inner surface 56 of the outer shell 34, two mutually parallel, rib-shaped support means 58 are formed between them form a groove-shaped receptacle 60 for the free ends of the support arms 50. In this recording, the radial contact surface 52 formed by the support arms 50 bears against the outer shell 34. Further, spherical bearing slip coupling means 62 are guided in the bearing recesses 54 of a total of 64 designated slip clutch whose maximum torque is adjustable via the adjusting sleeve 21.

When setting the side handle 22, the clamping band 24 is pushed onto the cylindrical outer surface 36 and tightened. Here, the outer shell 34 is supported in the region of the cylindrical outer surface 36 inwardly by the support body 44. In this way, 22 deformations on the main housing 4 are avoided when tightening the side handle, which could disturb the function of the slip clutch 64 or the transmission 16, for example.

During operation of the hand tool 2, a contact pressure P applied by an operator to the handle 10 or to the contact surface 8 in the working direction R is delivered directly to the support body 44 via the support means 58 facing the rear end 6. Since this rests against the inner surface 56, no offset moment arises here between the support arms 50 and the outer shell 34, from which a noticeable deformation of the support means 58 could result.

As an alternative support means 58 this would also be a sudden narrowing of the inner surface 56 in the direction of the rear end conceivable.

By resulting in both cases, particularly rigid support in working direction R achieves a particularly low-loss transmission of the contact pressure P from the main body 4 on the support body 44 and thus on the housing-fixed sprocket 43. This and the high mass of the metallic support body, the additional support effect has, by the ratchet impactor 38 transmitted to the tool holder 20 impact energy and thus the performance of the hand tool 2 can be significantly increased.

Claims (8)

1. Electric hand-held power tool (2)
   with a main housing (4) having a shell-type construction
   and a tool spindle (14) projecting from the main housing (4) at a tool-side end (18),
   with the tool spindle (14) being rotatable around an operational axis (A) by a motor (12) and a gear (16), which are arranged in the main housing (4), and
   with the tool spindle (14) being admittable by a ratchet striking mechanism (38) with pulse type axial movements, wherein the ratchet striking mechanism (38) comprises a ring gear (43) fixed to the main housing (4), where in the ring gear (43) is connected to a supporting body (44) supported at the main housing (4) and works together with a moveable ring gear (41) rotatable connected to the tool spindle (14),
   wherein the supporting body (44) is supported in a direction remote from the tool-side end (18) by supporting means (58),
   wherein the supporting means (58) are formed in a circumferentially extending manner at an inner surface (56) of an outer shell (34) of the main housing (4) and the supporting body (44) is directly connected to the supporting means (58),
   characterised in that the supporting body (44) comprises a sleeve-shaped basic body (48), from which several supporting arms (50) project radially, wherein the free ends of the several supporting arms (50) form a radial sup port surface (52) and the several supporting arms (50) are arranged on a far side of the basic body (48) turning away from the fixed ring gear (42) and a tool holder (20).
2. Hand-held power tool according to claim 1, characterised in that the supporting body (44) has a radial contact surface (52), which contacts the outer shell (34) circumferentially in the radial direction.
3. Hand-held power tool, according to claim 2, characterised in that the radial contact surface (52) contacts the inner surface (56) at an axial height of a cylindrical outer surface (36) of the outer shell (34).
4. Hand-held power tool according to one of claims 1 to 3, characterised in that the supporting body (44) is made of metal.
5. Hand-held power tool according to one of claims 1 to 4, characterised in that the supporting body (44) is held on a gear housing (46).
6. Hand-held power tool according to claim 5, characterised in that the supporting body (44) is cast integrally with the gear housing (46).
7. Hand-held power tool according to one of claims 1 to 6, characterised in that a spindle bearing (49) is pressed into the supporting body (44).
8. Hand-held power tool according to one of claims 1 to 7, characterised in that bearing recesses (54) for guiding slip clutch means (62) are incorporated in the supporting body (44).

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