DE102007003037A1 - impact wrench - Google Patents

Abstract

An impact wrench switchable to non-impact operation includes an input shaft (4), an output shaft (5), and a shock body (22) urged by the spring force toward the output shaft (5) and rotationally engaged with the output shaft (5) in a forward position. The striker (22) is drivingly connected to the drive shaft (4). Acts during impact operation on the output shaft (5) from the outside a limit counter-torque, the striker (22) moves against the spring force to the rear with superimposed rotational movement relative to the drive shaft (4). The striker (22) then rotates past the output shaft (5) and then returns under the spring force in its forward position and exerts on the output shaft (5) a blow in the circumferential direction. The switching device includes a radially outside of the drive shaft (4) arranged concentrically to this switching ring (35) rotatably and axially displaceably mounted on a rotatably connected to the drive shaft (4) switching ring bearing part (37) and when moving from an inoperative position in an operative position in rotationally fixed locking engagement with the impactor body (22) passes.

Description

The The invention relates to a beating operation on non-impact operation reversible impact wrench, with a motor driven Drive shaft, arranged coaxially to the drive shaft, relative to the drive shaft rotatably mounted output shaft and a concentric with the drive shaft on this stored, in driving Connection with the drive shaft standing and by a spring force in the axial direction to the output shaft acted upon impactor, in an advanced to the output shaft forward position is in rotational engagement with the output shaft and by at least a cam arrangement and an engaging in this control is connected to the drive shaft such that the impact mode of Impactor when on the output shaft from the outside no counter torque or a smaller counter torque than a limit counter torque acts, assumes its forward position and, if on the output shaft from the outside counteracts the limit counter-moment the spring force an axial movement to the rear with superimposed Rotary movement relative to the drive shaft executes itself the output shaft rotates past and then under the spring force returned to its front position and the output shaft a blow in the circumferential direction exercises.

impact wrench be used for tightening screws or loosening tightened screws used. This is the impact wrench attached to the respective screw and in the tightening or Loosen corresponding direction of rotation, so when Impact mode when the limit counter torque occurs consecutively, impulsive blows in the circumferential direction on the output shaft and thus be applied to the screw.

These Impact wrenches are usually hand tools.

One from the EP 1050381 A2 Known impact wrench can be switched from the described impact mode to a non-impact operation by the output shaft is always connected to the drive shaft, regardless of the counter-torque acting on them, so that the impact wrench works like a normal screwdriver, in which no impact function is integrated.

at the well-known impact wrench is a drive shaft in the axial Direction enforcing contact pin present, the switch over from impact to non-impact operation, so that it comes into rotationally fixed engagement with the output shaft and this directly rotatably connected to the drive shaft.

one the disadvantages of this impact wrench is that the switching pin a fairly small diameter, so only according to small torques transmitted from the drive shaft to the output shaft to let.

Of the present invention is based on the object, an impact wrench to create the type mentioned, the simple and stable Construction and easy handling of the impact mode can be switched to the non-impact mode and in non-impact mode transmitting relatively large torques allowed.

These The object is achieved according to the invention that the switching means for switching from the impact mode on the non-impact operation by means of an actuator operable from the outside, between a Impact mode assigned inactive position and the non-impact operation includes associated active position adjustable shift ring, the radially outside of the drive shaft concentric to this arranged and connected to a rotationally fixed to the drive shaft Shift ring bearing part rotatably and axially displaceable is mounted and when moving out of his ner let the impactor uninfluenced inoperative position to its operative position in non-rotatable locking engagement gets with the striker.

On this way, the striker is over in non-impact operation locked the switching ring with the drive shaft, so that the Do not twist the impactor relative to the drive shaft and thus can no longer shift axially. Therefore, the striking body no longer acting on the output shaft when acting on the limit counter-torque Dodge, so to speak, and out of engagement with the drive shaft reach. Therefore, the output shaft is always rotationally fixed to the drive shaft connected.

Of the Switching ring can be a relatively large Have diameter, so transmit correspondingly large torques can be.

expedient Embodiments of the invention are in the subclaims specified.

below An embodiment of the invention with reference to the drawing explained in detail. Show it:

1 an impact wrench according to the invention in an external view in an oblique view,

2 after the impact wrench 1 in partial view in side view, the housing of the impact wrench is removed in the present field of interest and the impact wrench is in the operating state "impact mode",

3 the arrangement after 2 in the operating state "non-impact operation",

4 the arrangement after 2 im to the drawing level of 2 parallel cut,

5 the arrangement after 4 in plan view according to arrow V, partly in section,

6 the arrangement after 2 in front view according to arrow VI and

7 the front portion of the drive shaft in a separate state in side view with schematically indicated cam arrangement with associated control.

From the drawing is a trained as a handheld impact wrench 1 with an electric drive motor 2 , one from the drive motor 2 driven gear unit 3 , one of the gear unit 3 driven drive shaft 4 and one coaxial with the drive shaft 4 arranged output shaft 5 protruding in an elongated device housing 6 , which may be formed in several parts, are included. From the device housing 6 stands one a handle 7 forming housing part 8th pistol-like.

The impact wrench 1 is designed as a cordless device. This is at the bottom of the handle 7 arranged a receptacle for a battery pack. Instead of using a rechargeable battery, however, the impact wrench could also be operated with mains power.

At the top of the handle 7 Front is a user-actuated pushbutton 10 arranged over which a lying in the power supply operating switch 11 is pressed.

The output shaft 5 is at the front of the device housing 6 before this before and can be connected with a turning tool for screwing or unscrewing a screw. The above output shaft area 12 is as a quadrilateral shaft 13 formed and contains an outgoing from its front polygonal recess 14 , On the square shaft 13 a conventional socket wrench can be attached non-rotatably, which has a polygonal receptacle for non-rotatable insertion of a polygonal screw head. Instead of a socket wrench can also be attached to the square shank a header, on which in turn a turning tool can be set. The polygonal recess 14 on the other hand can be used for non-rotatable insertion of a bit-like turning tool.

The impact wrench 1 is switchable from a flapping operation to a non-impact operation. In non-impact operation ( 3 ) is the output shaft 5 Independently of the torque to be applied or independently of the counter-torque acting on the output shaft from the screw to be driven in or out, it is non-rotatably connected without interruption to the drive shaft, so that the impact wrench 1 like a normal screwdriver works without impact function.

In hitting mode, on the other hand, when an outside is exceeded, the output shaft is turned on 5 applied limit counter-torque successive, pulse-like blows in the circumferential direction on the output shaft exerted, so tighten compared to the non-impact operation a screw and a stuck screw can be solved easily.

It is understood that the output shaft 5 can be driven either in both directions of rotation.

For the impact operation is a trained percussion available.

The output shaft 5 is relative to the drive shaft 4 rotatably mounted. In the embodiment, the drive shaft 4 at its output shaft 5 facing side of a bearing extension 16 on, in a storage recess 15 the output shaft 5 rotatably engaged. The output shaft 5 is by means of a arranged on its outer circumference pivot bearing 17 rotatable in the device housing 6 stored.

The output shaft 5 further comprises at least one, advantageously a plurality of, in particular two diametrically opposed, radially outwardly projecting output drive projections 18 . 19 on (see in particular the 2 . 3 and 6 ), so that in the circumferential direction between the output driving projections 18 . 19 interspaces 20 . 21 be formed.

On the drive shaft 4 is a concentric to the drive shaft 4 arranged impactor 22 mounted, in a manner to be described in driving connection with the drive shaft 4 stands, but on the drive shaft 4 can perform an axial movement with superimposed rotary motion. The impactor 22 is by one of a coil spring 23 applied spring force in the direction of the output shaft 5 acted upon and takes with the exception of the impact mode when acting on the limit counter-torque excess counter-torque under the spring force to the output wave 5 towards forward front position, which is shown in the drawing. In this front position is the striker 22 in rotational engagement with the output shaft 5 , For this purpose, the impactor 22 at its output shaft 5 facing end in the number of output driving projections 18 . 19 the output shaft 5 corresponding drive entrainment projections 24 . 25 on, in the axial direction of the striker 22 stand up and in the forward position of the impactor 22 each in one of the spaces 20 . 21 between the output driving projections 18 . 19 intervention.

The drive entrainment projections 24 . 25 have a smaller circumferential extent than the spaces between 20 . 21 between the output driving projections 18 . 19 so the striker 22 and the drive shaft 5 relative to each other a little bit are rotatable. If the striker is in its forward position, the drive lugs are located 24 . 25 in the direction of rotation of the drive shaft 4 at the output driving projections 18 . 19 on, so that the output shaft 5 is taken in the direction of rotation.

The impactor 22 and the drive shaft 4 are over two diametrically opposed cam arrangements 26 . 27 each associated with and in the respective cam arrangement 26 . 27 engaging control 28 . 29 in the form of a control ball 30 . 31 connected with each other. In principle, one of the two cam arrangements would suffice.

In the embodiment, each cam arrangement 26 . 27 a V-shaped extending Steuerut 32 on the outer circumference of the drive shaft 4 on, in which the respective control ball 30 . 31 intervenes. The tip of the V-shape of the rudder groove 32 is the drive shaft 5 facing. The respective control ball 30 . 31 is from the relevant tax groove 32 the drive shaft 4 before and is located on a respective control surface 33 on the inner circumference of the impactor 22 at. In 7 is the control surface 33 indicated by dash-dotted lines. The control area 33 is on the inner circumference of the impactor 22 at the transition to one of the output shaft 5 facing extension 34 the internal cross section of the impactor 22 educated. The control area 33 also has a V-shaped course, the tip of the V, however, the output shaft 5 turned away. Instead of the control surface 33 could be on the inner circumference of the impactor 22 However, a control groove corresponding course be provided. In the initial rotational position, that is, when the striker 22 assumes its front position, there is the respective control ball 30 . 31 , like out 7 shows at the top of the V-shaped cam 32 and the top of the V-shaped control surface 33 ,

With the help of this at least one cam arrangement 26 . 27 and associated control ball 30 . 31 leads the striker 22 during impact operation, when on the output shaft 5 from the outside, a larger counter-moment than the limit counter-torque is exerted, against the spring force an axial movement to the rear with superimposed rotary motion relative to the drive shaft 4 out, so that the striking body 22 on the output shaft 5 turned over and then under the spring force forward again in the forward position and thereby with its drive-driving projections 24 . 25 in the interstices 20 . 21 against the output driving projections 18 . 19 the output shaft 5 moved, so that in the circumferential direction a blow to the output driving projections 18 . 19 and thus on the output shaft 5 is exercised.

To switch from this impact mode to the non-impact mode is a switching ring 35 present, by means of an actuator 36 can be actuated from the outside and thereby adjustable between an inactive position assigned to the impact mode and an effective position assigned to the non-impact mode. The switching ring 35 is radially outside the drive shaft 4 arranged concentrically to this. Here is the switching ring 35 at a rotationally fixed to the drive shaft 4 connected switching ring bearing part 37 rotatably mounted and axially displaceable. In its inoperative position ( 2 . 4 and 5 ) is the switching ring 35 from the striker 22 removed, leaving the striker 22 unaffected by the switching ring 35 is. Moves the switching ring 35 in contrast, in its effective position to the striker 22 out, the switching ring arrives 35 in non-rotatable locking engagement with the striker 22 , For this purpose, the switching ring 35 several arranged distributed over the circumference, the impactor 22 protruding locking projections 38 (in principle, only such a locking projection could 38 to be available). Each locking tab 38 is one at the facing end of the impactor 22 arranged locking recess 39 assigned. When transferring the switching ring 35 in its operative position engage the locking projections 38 in the locking recesses 39 one, so the striker 22 rotatably with the switching ring 35 connected is. Conversely, the arrangement could also be made so that the locking projections on the striker and the locking recesses are arranged on the switching ring.

Because the switching ring 35 on the other hand rotatably with the switching ring bearing part 37 which in turn is in rotationally fixed connection with the drive shaft 4 stands, results in the effective position of the switching ring 35 a non-rotatable connection of the impactor 22 with the drive shaft 4 , At the same time, the striker can 22 not in anymore move the axial direction, so the impactor 22 regardless of the outside on the output shaft 5 applied counter-torque in rotational engagement with the output shaft 5 stands.

Another advantage of the impact wrench 1 is that the striker 22 in the inoperative position of the Schaltrings 35 when the impact wrench is switched off, such a rotational position automatically relative to the switching ring 35 assumes that the locking recesses 39 of the impactor 22 in the axial direction in alignment with the locking projections 38 the Schalring 35 are arranged so that the switching ring 35 in its advancement into the operative position with its locking projections 38 Immediately into the locking recesses 39 of the impactor 22 occurs and no further manipulations are required to the locking projections 38 and the locking recesses 39 to bring in an aligned position. This is due to the impactor 22 acting spring force and the at least one cam assembly 26 . 27 with associated control ball 30 . 31 ,

Furthermore, it is expediently provided that the between each two Verriegelungsausnehmungen 39 arranged end face areas 40 . 41 of the impactor 22 one with respect to the mouths of the locking recesses 39 have to reset course, so that said end face areas 40 . 41 Depressions on the front side of the impactor 22 form. In this way it is avoided that in the impact mode, the locking projections 38 the Schalring 35 with the front of the impactor 22 can collide.

The gear unit 3 contains a drive shaft 4 driving planetary gear. On the output side, this planetary gearset contains a set of planetary gears distributed over the circumference 42 radially inward with one from the drive motor 2 driven sun wheel 43 and radially outward with a set of planetary gears 42 enclosing ring gear 44 comb. The planet wheels 42 are each on a planetary gear shaft 45 rotatably mounted, by an annular circumferential web body 46 stick out, at the the striker 22 facing side of the planetary gear set 42 is arranged. The drive shaft 4 is rotationally fixed and axially fixed to the web body 46 connected so that the drive shaft 4 is driven via the planetary gear.

In the embodiment, it is a multi-stage, switchable planetary gear. In the present case, however, it is only essential that the planetary gear a the impactor 22 having facing web body, that is, the web body 46 , This bridge body 46 is designed so that it also the switching ring bearing part 37 forms. Here is the switching ring 35 on the outer circumference of the web body 46 rotatably mounted and axially displaceable. In this way, no separate switching ring bearing part is required, resulting in a low-part arrangement.

The bridge body 46 has a smaller diameter than the impactor 22 on, so the bridge body 46 , like from the 4 and 5 can be seen, a little way into the striker 22 dips.

For non-rotatable, but axially displaceable mounting of the switching ring 35 on the bridge body 46 are on the outer circumference of the web body 46 groove-like, axially directed guideways 47 arranged. The arrangement is suitably made so that the locking projections 38 the Schalring 35 radially inward in the guideways 47 run and when switching to the non-impact operation with its radially outer region in the locking recesses 39 of the impactor 22 intervention.

The the striking body 22 forward acting coil spring 23 rests with its rear end on the bridge body 46 from, which is arranged fixed in the axial direction. The coil spring 23 rotates during operation of the impact wrench 1 With.

The impactor 22 has an open towards the rear, annular circumferential recess 48 on, in which the coil spring 23 engages and is stored with the relevant end. The bridge body 46 also forms an annular circumferential recess 49 which is open towards the front and the rear end of the coil spring 23 receives. This contributes to the space-saving design. In principle, only one of the two recesses could 48 . 49 , Expediently, the recess 48 in the striker 22 , to be available.

The actuating device 36 with which the switching ring 35 can be displaced, has an outside of the device housing 6 movably arranged actuating element 50 on whose movement the axial displacement movement of the switching ring 35 is derived. For this purpose, the switching ring 35 on its outer circumference a circumferential annular groove 51 in, in which a suitably U-like switch bracket 52 engages, which preferably consists of wire material. The switch bracket 52 is movable in the axial direction and is by means of the actuating element 50 actuated.

When operating the impact wrench 1 remains the switch bracket 52 in the direction of rotation, and the switching ring 35 turns on the handlebar 52 past.

The actuator 50 is in the expedient embodiment of an annular, rotatable on the housing 6 mounted rotary valve 53 formed with the switch bracket 52 is connected so that its rotational movement in the axial displacement movement of the switching ring 35 is implemented. This motion conversion takes place by means of a flat shape having deflecting part 54 , on the one hand, the switch bracket 52 carries and on the other hand with the rotary valve 53 engaged so that the switch bracket 52 and with this the switching ring 35 moved in the axial direction when turning the rotary valve 53 twisted.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1050381 A2 [0004]

Claims (12)

From impact mode to non-impact mode switchable impact wrench, with a motor-driven drive shaft ( 4 ), one coaxial to the drive shaft ( 4 ), relative to the drive shaft ( 4 ) rotatably mounted output shaft ( 5 ) and a concentric with the drive shaft ( 4 ) on this bearing, in driving connection with the drive shaft ( 4 ) and by a spring force in the axial direction to the drive shaft ( 5 ) acted upon impactor ( 22 ), which in one to the drive shaft ( 5 ) advanced forward position in rotational engagement with the output shaft ( 5 ) and by at least one cam arrangement ( 26 . 27 ) and an intervening control ( 28 . 29 ) with the drive shaft ( 4 ) is connected in such a way that during striking operation the striking body ( 22 ), when on the output shaft ( 5 ) acts from the outside no counter-torque or a smaller counter-moment as a limit counter-torque, assumes its front position and, if on the output shaft ( 5 ) acts from the outside the limit counter-torque, against the spring force an axial movement to the rear with superimposed rotary motion relative to the drive shaft ( 4 ), located on the output shaft ( 5 ) and then returns under the spring force in its front position and on the output shaft ( 5 ) exerts a stroke in the circumferential direction, characterized in that the switching means for switching from the impact operation to the non-impact operation by means of an actuating device ( 36 ) operable from the outside, between an inoperative position associated with impact operation and an operative position associated with non-impact operation ((US Pat. 35 ), which is radially outside the drive shaft ( 4 ) arranged concentrically to this and at a rotationally fixed to the drive shaft ( 4 ) connected switching ring bearing part ( 37 ) is rotatably mounted and axially displaceable and when moving from his the impactor ( 22 ) unaffected inactive position in its operative position in non-rotatable locking engagement with the impactor body ( 22 ). Impact wrench according to claim 1, characterized in that the locking engagement by means of at least one locking projection ( 38 ) at the switching ring ( 35 ) or on the striking body ( 22 ) and at least one locking recess ( 39 ) on the striking body ( 22 ) or on the switching ring ( 35 ), whereby the impactor ( 22 ) in the inoperative position of the switching ring ( 35 ) when the impact wrench is switched off, automatically such a rotational position relative to the switching ring ( 35 ) in which the at least one locking recess ( 39 ) or the at least one locking projection on the striking body ( 22 ) in the axial direction aligned with the at least one locking projection ( 38 ) or at least one locking recess ( 39 ) at the switching ring ( 35 ) is arranged. Impact wrench according to claim 2, characterized in that the at least one control cam arrangement ( 26 . 27 ) has a V-like shape and the control ( 28 . 29 ) from a control ball ( 30 . 31 ) is formed, so that in the initial rotational position the control ball ( 30 . 31 ) is located at the top of the respective V. Impact wrench according to claim 2 or 3, characterized in that the impactor ( 22 ) at its the switching ring ( 35 ) facing a plurality of circumferentially spaced locking recesses ( 39 ) and between each two Verriegelungsausnehmungen ( 39 ) arranged end face areas ( 40 . 41 ) of the impactor ( 22 ) with respect to the mouths of the locking recesses ( 39 ) have recessed course. Impact wrench according to one of claims 1 to 4, characterized in that the drive shaft ( 4 ) is driven by a planetary gear, the one the impactor ( 22 ) facing, rotationally fixed and axially fixed to the drive shaft ( 4 ) connected web body ( 46 ), which is used as the switching ring ( 35 ) rotatably on its outer circumference and axially displaceably bearing switching ring bearing part ( 37 ) is trained. Impact wrench according to one of claims 1 to 5, characterized in that the impactor ( 22 ) engaging spring force from a coil spring ( 23 ) is applied. Impact wrench according to claim 6, characterized in that the helical spring ( 23 ) on the web body ( 46 ) is supported. Impact wrench according to claim 7, characterized in that the striking body ( 22 ) and / or the web body ( 46 ) at its the web body ( 46 ) or the impactor ( 22 ) facing end face an annular circumferential recess ( 48 respectively 49 ) for supporting the coil spring ( 23 ) having. Impact wrench according to one of claims 5 to 8, characterized in that the web body ( 46 ) a smaller diameter than the impactor ( 22 ) and a little way into the striking body ( 22 immersed). Impact wrench according to one of claims 1 to 9, characterized in that the actuating device ( 36 ) on the outside of the housing ( 6 ) of the impact wrench movably arranged actuating element ( 50 ), whose movement the axial displacement movement of the switching ring ( 35 ) is derived. Impact wrench according to claim 10, characterized in that the switching ring ( 35 ) has on its outer circumference a circumferential annular groove ( 51 ), in which a movable in the axial direction, by means of the actuating element ( 50 ) operable switch bracket ( 52 ) intervenes. Impact wrench according to claim 11, characterized in that the actuating element ( 50 ) of an annular, rotatable on the housing ( 6 ) of the impact wrench mounted rotary valve ( 53 ) formed with the switch bracket ( 52 ) is connected so that its rotational movement in the axial displacement movement of the switching ring ( 35 ) is implemented.