Hammer mechanism

Abstract

A hammer mechanism has a clamping chuck and a snap die provided for the direct striking of an inserted tool. The snap die includes a coupling element for transmitting a rotary motion to the clamping chuck.

Claims

1. A hammer mechanism of an apparatus, the hammer mechanism being configured for striking a tool inserted into the apparatus, comprising: a clamping chuck; a clamping chuck drive shaft; and a snap die configured to directly strike the inserted tool, wherein the clamping chuck drive shaft is joined to the snap die in a torsionally fixed and axially displaceable manner, wherein the clamping chuck drive shaft is configured to directly act on the snap die, wherein the snap die includes a coupling element for transmitting a rotary motion of the clamping chuck drive shaft to the clamping chuck.

2. The hammer mechanism as recited in claim 1, wherein the clamping chuck includes an inserted-tool coupling region with which the coupling element of the snap die engages at least partially.

3. The hammer mechanism as recited in claim 2, further comprising: a clamping chuck drive shaft for transmitting a rotary motion to the snap die.

4. The hammer mechanism as recited in claim 3, wherein the clamping chuck drive shaft is at least partially disposed in a recess of the snap die in at least one operating state.

5. The hammer mechanism as recited in claim 2, wherein the snap die includes a sealing region which rests against the clamping chuck without gear teeth.

6. The hammer mechanism as recited in claim 3, further comprising: a hammer element which is mounted by the clamping chuck drive shaft in a manner allowing movement in a strike direction in at least one operating state.

7. The hammer mechanism as recited in claim 6, wherein the clamping chuck drive shaft at least partially penetrates the hammer element.

8. The hammer mechanism as recited in claim 6, wherein the hammer element is configured to provide a strike pulse in the strike direction.

9. The hammer mechanism as recited in claim 6, wherein the strike direction is an axial strike direction.

10. The hammer mechanism as recited in claim 3, further comprising: an impact-generation deactivation unit having a blocking element which acts on the snap die parallel to a force of the clamping chuck drive shaft, in at least a drilling operation.

11. The hammer mechanism as recited in claim 3, further comprising: a planetary gearing which drives the clamping chuck drive shaft in at least one operating state.

12. The hammer mechanism as recited in claim 3, further comprising: an impact-generation unit; and a coupling element which is connected to the clamping chuck drive shaft in a torsionally-fixed manner and drives the impact-generation unit.

13. The hammer mechanism as recited in claim 1, wherein the snap die is mounted to the clamping chuck in an axially movable manner.

14. A hand-held tool, comprising: an inserted tool element; and a hammer mechanism having a clamping chuck, a clamping chuck drive shaft, and a snap die configured to directly strike the inserted tool element, wherein the clamping chuck drive shaft is joined to the snap die in a torsionally fixed and axially displaceable manner, wherein the clamping chuck drive shaft is configured to directly act on the snap die, and wherein the snap die includes a coupling element for transmitting a rotary motion of the clamping chuck drive shaft to the clamping chuck.

15. A hammer mechanism of an apparatus, the hammer mechanism being configured for striking a tool inserted into the apparatus, comprising: a clamping chuck; a snap die configured to directly strike the inserted tool; a clamping chuck drive shaft for transmitting a rotary motion to the snap die; and a hammer element which is mounted by the clamping chuck drive shaft in a manner allowing movement in a strike direction in at least one operating state, wherein the snap die includes a coupling element for transmitting a rotary motion to the clamping chuck, wherein the clamping chuck drive shaft at least partially penetrates the hammer element.

16. A hammer mechanism of an apparatus, the hammer mechanism being configured for striking a tool inserted into the apparatus, comprising: a clamping chuck; a snap die configured to directly strike the inserted tool; a clamping chuck drive shaft for transmitting a rotary motion to the snap die; and an impact-generation deactivation unit having a blocking element which acts on the snap die parallel to a force of the clamping chuck drive shaft, in at least a drilling operation, wherein the snap die includes a coupling element for transmitting a rotary motion to the clamping chuck.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a perspective view of a handheld tool having a hammer mechanism according to the present invention.

(2) FIG. 2 shows a section of the hammer mechanism of FIG. 1.

(3) FIG. 3 shows coupling means, a clamping chuck drive shaft, a snap die, and a portion of a clamping chuck of the hammer mechanism from FIG. 1, shown individually in a perspective view in each case.

(4) FIG. 4 shows another part-sectional view of the hammer mechanism from FIG. 1, which shows an impact-generation deactivation unit of the hammer mechanism.

(5) FIG. 5 shows a schematic representation of a first alternative exemplary embodiment of a snap die of the hammer mechanism from FIG. 1.

(6) FIG. 6 shows a schematic representation of a second alternative exemplary embodiment of a snap die of the hammer mechanism from FIG. 1.

(7) FIG. 7 shows a sectional view of a third alternative exemplary embodiment of a snap die of the hammer mechanism from FIG. 1.

(8) FIG. 8 shows a first perspective view of the snap die from FIG. 7.

(9) FIG. 9 shows a second perspective view of the snap die from FIG. 7.

(10) FIG. 10 shows a perspective view of a portion of a clamping chuck of the hammer mechanism of FIG. 7.

(11) FIG. 11 shows a schematic representation of a fourth alternative exemplary embodiment of a snap die of the hammer mechanism from FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(12) FIG. 1 shows a handheld tool 10a, which is developed as impact drill screwer. Handheld tool 10a has a pistol-shaped housing 12a. A drive motor 14a of handheld tool 10a is situated inside housing 12a. Housing 12a has a handle region 16a and a battery coupling means 18a, which is disposed at an end of handle region 16a facing away from drive motor 14a. Battery coupling means 18a links a handheld tool rechargeable battery 20a, which link is able to be severed by an operator, electrically or mechanically. Handheld tool battery 20a has an operating voltage of 10.8 Volt, but could also have a different operating voltage, especially a higher voltage. Furthermore, handheld tool 10a is provided with a hammer mechanism 22a according to the present invention, which includes a clamping chuck 24a disposed on the outside, and operating elements 26a, 28a.

(13) FIG. 2 shows hammer mechanism 22a in a sectional view. Hammer mechanism 22a also includes a planetary gearing 30a and a clamping chuck drive shaft 32a. When in operation, planetary gearing 30a drives clamping chuck drive shaft 32a so that it executes rotary motions about an axis of rotation. Planetary gearing 30a has three planetary gear stages 34a, 36a, 38a for this purpose. The transmission ratio of planetary gearing 30a between a rotor 40a of drive motor 14a and a clamping chuck drive shaft 32a is adjustable in at least two stages by an operator. As an alternative, a transmission ratio between drive motor 14a and clamping chuck drive shaft 32a could also be designed to be non-adjustable.

(14) Hammer mechanism 22a has a torque restriction device 42a, which fixates a ring gear 44a of planetary gearing 30a during a working operation. Torque restriction device 42a is provided with fixation balls 46a for this purpose, which engage with recesses of ring gear 44a. A spring 48a of torque restriction device 42a exerts a force in the direction of ring gear 44a on fixation balls 46a. Using one of operating elements 26a, the operator is able to move an end of spring 48a facing fixation balls 46a in the direction of fixation balls 46a. Operating element 26a includes an eccentric element for this purpose. The force acting on fixation balls 46a thus is adjustable. If a particular maximum torque has been reached, fixation balls 46a are pushed out of the recesses and ring gear 44a runs freely, thereby interrupting a force transmission between rotor 40a and clamping chuck drive shaft 32a. Torque restriction device 42a thus is provided to restrict a maximum torque that is transmittable via clamping chuck drive shaft 32a.

(15) Hammer mechanism 22a includes an impact-generation unit 50a and first coupling means 52a. First coupling means 52a is connected to clamping chuck drive shaft 32a in torsionally fixed manner, i.e., first coupling means 52a and clamping chuck drive shaft 32a are formed in one piece, in particular. Impact-generation unit 50a includes a second coupling means 54a, which is connected to first coupling means 52a in torsionally fixed manner in a drilling and/or impact drilling mode. As shown in FIG. 3 as well, first coupling means 52a is developed as premolded shape and second coupling means 54a is developed as recess. When the drilling mode is activated, first coupling means 52a dips into second coupling means 54a, i.e., to the full extent. As a result, the coupling between first coupling means 52a and second coupling means 54a is reversible by axial shifting of clamping chuck drive shaft 32a in the direction of clamping chuck 24a. A spring 56a of hammer mechanism 22a is situated between first coupling means 52a and second coupling means 54a. Spring 56a pushes clamping chuck drive shaft 32a in the direction of clamping chuck 24a. When impact-generation unit 50a is deactivated, it opens the link between first coupling means 52a and second coupling means 54a.

(16) Hammer mechanism 22a is provided with a first bearing 58a, which fixates second coupling means 54a relative to housing 12a in the axial direction and rotationally mounts it coaxially with clamping chuck drive shaft 32a. Furthermore, hammer mechanism 22a is provided with a second bearing 60a, which rotationally mounts clamping chuck drive shaft 32a on a side facing drive motor 14a, so that it is able to rotate about the axis of rotation. Second bearing 60a is integrally formed with one of the three planetary gear stages 38a. Clamping chuck drive shaft 32a has a coupling means 62a, which connects it to a planet carrier 64a of this planetary gear stage 38a in axially displaceable and torsionally fixed manner. This planetary gear stage 38a consequently is provided to mount clamping chuck drive shaft 32a in axially displaceable manner. On a side facing clamping chuck 24a, a clamping chuck bearing rotationally mounts clamping chuck drive shaft 32a together with clamping chuck 24a. Clamping chuck bearing 70a includes a rear bearing element which is pressed onto clamping chuck 24a in axially fixated manner. In addition, clamping chuck bearing 70a has a front bearing element which supports clamping chuck 24a inside housing 12a in axially displaceable manner.

(17) Impact-generation unit 50a is equipped with a spur gear transmission stage 72a, which translates a rotational speed of clamping chuck drive shaft 32a into a higher rotational speed for the impact generation. A first toothed wheel 74a of spur gear transmission stage 72a is integrally formed with second coupling means 54a. In an impact-drilling operation, it is driven by clamping chuck drive shaft 32a. A second toothed wheel 76a of spur gear transmission stage 72a is integrally formed with a hammer mechanism shaft 78a. An axis of rotation of hammer mechanism shaft 78a is situated next to the axis of rotation of clamping chuck drive shaft 32a in the radial direction. Impact-generation unit 50a includes two bearings 80a, which mount hammer mechanism shaft 78a in axially fixated, rotatable manner. Impact-generation unit 50a is provided with a drive means 82a, which translates a rotary motion of hammer mechanism shaft 78a into a linear motion. An eccentric element 84a of drive means 82a is integrally formed with hammer mechanism shaft 78a. An eccentric sleeve 86a of drive means 82a is mounted on eccentric element 84a with the aid of a needle roller bearing, in a manner that allows it to rotate relative to eccentric element 84a. Eccentric sleeve 86a has a recess 88a, which encloses a rocker lever 90a of impact-generation unit 50a.

(18) Rocker lever 90a is pivotably mounted on a pivot axle 92a of impact-generation unit 50a, that is to say, it is able to pivot about an axis aligned perpendicularly to the axis of rotation of clamping chuck drive shaft 32a. An end of rocker lever 90a facing away from drive means 82a partially encloses a strike means 94a of hammer mechanism 22a. In so doing, the rocker lever engages in a recess 96a of strike means 94a, which is developed in the form of a ring. In an impact-drilling operation, rocker lever 90a exerts a force on strike means 94a, which accelerates it. While in operation, rocker lever 90a moves in a sinusoidal pattern. Rocker lever 90a has an elastic form. It has a spring constant between eccentric sleeve 86a and strike means 94a that is less than 100 N/mm and greater than 10 N/mm. In this exemplary embodiment, rocker lever 90a has a spring constant of approximately 30 N/mm.

(19) Clamping chuck drive shaft 32a mounts strike means 94a so that it is movable in strike direction 98a. To do so, strike means 94a delimit a recess 100a. Clamping chuck drive shaft 32a penetrates strike means 94a through recess 100a. In so doing, strike means 94a encloses recess 100a over 360 degrees in a plane perpendicular to recess 100a. When operated, strike means 94a strikes a snap die 102a of hammer mechanism 22a, which is situated between an inserted tool 104a and strike means 94a. In an operative state, inserted tool 104a is fixed in place inside clamping chuck 24a. Clamping chuck 24a mounts snap die 102a in a manner that allows it to move parallel to strike direction 98a. In an impact-drilling operation, strike pulses originating from strike means 94a are transmitted to inserted tool 104a by snap die 102a.

(20) Clamping chuck drive shaft 32a is connected to snap die 102a in axially movable and torsionally fixed manner. Snap die 102a delimits a recess 106a for this purpose. In an operative state, clamping chuck drive shaft 32a is partially situated inside recess 106a of snap die 102a. Clamping chuck drive shaft 32a is rotationally mounted via snap die 102a, clamping chuck 24a and clamping chuck bearing 70a. Clamping chuck 24a is driven in rotating manner via snap die 102a. For this purpose, clamping chuck 24a and snap die 102a each include coupling means 108a, 110a, which are provided to transmit the rotary motion to clamping chuck 24a. Coupling means 108a of snap die 102a is developed as a groove, whose main extension is situated parallel to strike direction 98a. Coupling means 108a extends along a radially outward-lying surface area of snap die 102a. Coupling means 110a of clamping chuck 24a is implemented as a protrusion that fits the groove.

(21) Clamping chuck 24a includes an inserted-tool coupling region 112a, in which inserted tool 104a is fixated in strike direction 98a during a drilling or screwing operation, or in which it is mounted so as to allow movement in strike direction 98a during an impact-drilling operation. In addition, the clamping chuck includes a tapered region 114a, which delimits a movement range of snap die 102a in strike direction 98a. Furthermore, clamping chuck 24a is provided with a mounting ring 116a, which delimits a movement range of snap die 102a counter to strike direction 98a.

(22) During an impact-drilling operation, an operator presses inserted tool 104a against a workpiece (not shown further). The operator thereby shifts inserted tool 104a, snap die 102a and clamping chuck drive shaft 32a relative to housing 12a in a direction counter to the strike direction 98a, i.e., in the direction of drive motor 14a. In so doing, the operator compresses spring 56a of hammer mechanism 22a. First coupling means 52a dips into second coupling means 54a, so that clamping chuck drive shaft 32a begins to drive impact-generation unit 50a. When the operator stops pressing inserted tool 104a against the workpiece, spring 56a shifts clamping chuck drive shaft 32a, snap die 102a and inserted tool 104a in strike direction 98a. This releases a torsionally fixed connection between first coupling means 52a and second coupling means 54a, so that impact-generation unit 50a is switched off.

(23) Hammer mechanism 22a has an impact-generation deactivation unit 118a, which includes a blocking element 120a, a sliding block guide 122a, and operating element 28a. In a drilling or screwing mode, blocking element 120a exerts a force on snap die 102a, which acts on snap die 102 parallel to at least a force of clamping chuck drive shaft 32a. The force of blocking element 120a is acting on snap die 102a via clamping chuck bearing 70a, clamping chuck 24a, and mounting ring 116a. The force of blocking element 120a prevents an axial displacement of snap die 102a and clamping chuck drive shaft 32a during a drilling and screwing mode, and thus prevents an activation of impact-generation unit 50a. The force of clamping chuck drive shaft 32a has a functionally parallel component which drives snap die 102a in rotating fashion during operation. In addition, the force has a functionally and directionally parallel component which spring 56a exerts on snap die 102a via clamping chuck drive shaft 32a.

(24) FIG. 4 shows a section that runs perpendicularly to the section of FIG. 2 and parallel to strike direction 98a, operating element 28a being shown in two different positions in the sections of FIGS. 2 and 4. Operating element 28a is developed in the form of a ring and encloses the axis of rotation of clamping chuck drive shaft 32a in coaxial manner. Operating element 28a is mounted so as to be rotatable. It is connected to sliding block guide 122a in torsionally fixed manner. Sliding block guide 122a is likewise developed in the form of a ring. Sliding block guide 122a has a bevel 124a, which connects two surfaces 126a, 128a of sliding block guide 122a, Surfaces 126a, 128a are aligned perpendicularly to strike direction 98a. Surfaces 126a, 128a are disposed in different planes in strike direction 98a.

(25) In an impact-drilling mode, blocking element 120a is situated inside a recess 130a, which, for one, is delimited by bevel 124a and one of surfaces 126a. This surface 126a is situated closer to drive motor 14a than the other surface 128a. Housing 12a includes a housing element 132a, which mounts the blocking element in torsionally fixed manner and allows it move in strike direction 98a. At the start of an impact-drilling operation, blocking element 120a, together with clamping chuck 24a, therefore is able to be pushed in a direction counter to the strike direction 98a. In an impact-drilling operation, blocking element 120a does not exert a blocking force on clamping chuck 24a. When operating element 28a of impact-generation deactivation unit 118a is rotated, blocking element 120a is moved in strike direction 98a by bevel 124a.

(26) In the drilling or screwing mode, blocking element 120a is kept in this frontal position. In this way blocking element 120a prevents axial shifting of clamping chuck drive shaft 32a in the drilling or screwing mode.

(27) FIGS. 5 through 11 show additional exemplary embodiments of the present invention. The following descriptions and the figures are essentially limited to the differences between the exemplary embodiments. Regarding components designated in the same way, particularly regarding components bearing identical reference numerals, it is basically possible to refer also to the drawings and/or the description of the other exemplary embodiments, especially of FIGS. 1 through 4. In order to distinguish the exemplary embodiments, the letter a has been added after the reference numerals of the exemplary embodiment in FIGS. 1 through 4. In the exemplary embodiments of FIGS. 5 through 11, the letter a was replaced by the letters b through e.

(28) FIG. 5 shows a portion of a hammer mechanism 22b. A hammer means 94b of an impact-generation unit 50b of hammer mechanism 22b is mounted in movable manner on a clamping chuck drive shaft 32b of hammer mechanism 22b. Clamping chuck drive shaft 32b is joined to a snap die 102b of hammer mechanism 22b in torsionally fixed and axially displaceable manner. Snap die 102b is provided with a coupling means 108b which forms a torsionally fixed connection to a clamping chuck 24b of hammer mechanism 22b in at least one operating state. Coupling means 108b is situated on a side that is facing a tapered region 114b of clamping chuck 24b and developed as teething. A sealing region 134b of the snap die is resting against clamping chuck 24b without gear teeth and advantageously prevents dust from entering impact-generation unit 50b.

(29) FIG. 6, like FIG. 5, schematically illustrates a portion of hammer mechanism 22c. A hammer means 94c of an impact-generation unit 50c of hammer mechanism 22c is mounted in movable manner on a clamping chuck drive shaft 32c of hammer mechanism 22c. Clamping chuck drive shaft 32c is joined to a snap die 102b of hammer mechanism 22c in torsionally fixed and axially displaceable manner. Snap die 102c includes a coupling means 108c which forms a torsionally fixed connection to a clamping chuck 24c of hammer mechanism 22c in at least one operating state. Clamping chuck 24c is provided with an inserted-tool coupling region 112c, with which coupling means 108c of snap die 102c engages at least partially. The one inserted-tool coupling region 112c is provided to apply forces on an inserted tool in the peripheral direction during operation. In an operative state, coupling means 108c is at least partially disposed inside a tapered region 114c of clamping chuck 24c. Coupling means 108c is developed in the form of an external hexagon. The dimensions of the external hexagon correspond to the usual dimensions of a bit for a screwing operation. A sealing region 134c of the snap die 102c rests against clamping chuck 24c without gear teeth and advantageously prevents dust from entering impact-generation unit 50b in a cost-effective manner. Especially fat loss is able to be minimized.

(30) FIGS. 7 through 10 also show a portion of a hammer mechanism 22d as a section and in a perspective view. A hammer means 94d of an impact-generation unit 50d of hammer mechanism 22d is mounted in movable manner on a clamping chuck drive shaft 32d of hammer mechanism 22d. Clamping chuck drive shaft 32d is joined to a snap die 102d of hammer mechanism 22d in torsionally fixed and axially displaceable manner. Snap die 102d includes a coupling means 108d, which forms a torsionally fixed connection to a clamping chuck 24d of hammer mechanism 22d in at least one operating state. In an operative state, coupling means 108d is at least partially disposed inside a tapered region 114d of clamping chuck 24d. Coupling means 108d is developed as teething, which includes two coupling ribs that lie opposite each other in relation to the axis of rotation. Coupling means 108d has the same form and the same dimensions as a coupling means for the coupling with an inserted tool. The form and the dimensions correspond to those of the SDS Quick standard. A sealing region 134d of snap die 102d rests against clamping chuck 24d without gear teeth.

(31) FIG. 11, like FIG. 5, schematically illustrates a portion of hammer mechanism 22e. A hammer means 94e of an impact-generation unit 50e of hammer mechanism 22e is movably mounted on a clamping chuck drive shaft 32e of hammer mechanism 22e. Clamping chuck drive shaft 32e is joined to a snap die 102e of hammer mechanism 22e in torsionally and axially fixed manner. Clamping chuck drive shaft 32e and snap die 102e are developed in one piece. In an impact, hammer means 94e moves both clamping chuck drive shaft 32e and snap die 102e in strike direction 98e. With the aid of a coupling means 62e, clamping chuck drive shaft 32e is connected in axially displaceable and torsionally fixed manner to a planetary-gear stage described in the exemplary embodiment of FIGS. 1 through 4.