hand-held power tool with a percussion unit

Abstract

In a hand-held power tool, in particular a demolition, drilling or chiseling hammer, with a tool holder (140) for receiving a tool insert (145) and a housing in which a drive motor and a percussion unit (150) driven by the drive motor are arranged, wherein the percussion unit (150) is associated with at least one percussion housing (155) in which at least one impact element (210) and a piston element (220) acted upon by the impact element (210) for the impactive drive of the tool insert (145) are arranged, the piston element (220) is arranged to be guided section by section in the tool holder (140) in the longitudinal direction (299) of the percussion housing (155), and an impact element guide element (240) for guiding the impact element (210) is designed to be movable in the longitudinal direction (299) relative to the tool holder (140).

Description

State of the art

[0001] The present invention relates to a hand-held power tool, in particular a demolition hammer, drill hammer or chisel hammer, with a tool holder for receiving an insert tool and a housing in which a drive motor and an impact mechanism unit driven by the drive motor are arranged, wherein the impact mechanism unit is assigned at least one impact mechanism housing in which at least one impact means and a piston element which can be acted upon by the impact means for the impact drive of the insert tool are arranged.

[0002] Such a handheld power tool, designed as a demolition hammer, is known from the prior art. The demolition hammer is provided with a tool holder for holding an insert tool. Furthermore, the demolition hammer has a housing in which a drive motor and a percussion unit driven by the drive motor are arranged. Associated with the percussion unit is at least one percussion housing, in which at least one percussion element and a piston element actuated by the percussion element are arranged for driving the insert tool. Disclosure of the invention

[0003] The invention relates to a handheld power tool, in particular a demolition hammer, drill hammer, or chisel hammer, having a tool holder for holding an insert tool and a housing in which a drive motor and an impact mechanism unit driven by the drive motor are arranged, wherein the impact mechanism unit is assigned at least one impact mechanism housing in which at least one impact means and a piston element actuated by the impact means for impact-driving the insert tool are arranged. The piston element is arranged so as to be guided in sections in the longitudinal direction of the impact mechanism housing, and an impact mechanism guide element for guiding the impact means is designed to be movable in the longitudinal direction relative to the tool holder.

[0004] The invention thus makes it possible to provide a hand-held power tool in which the impact means guide element, which can be moved relative to the tool holder, enables the formation of a stable and robust impact mechanism unit.

[0005] The impact mechanism guide element is preferably mounted in the impact mechanism housing so that it can move in the longitudinal direction.

[0006] This allows for easy and uncomplicated storage of the impact guide element.

[0007] Preferably, the impact means guide element has coupling elements for coupling to the tool holder in the circumferential direction.

[0008] This makes it possible to easily couple the impact guide element and the tool holder to transmit rotation.

[0009] Preferably, the impact means guide element has at least one recess which is closed in a load position of the impact mechanism unit to form an air spring and is open in an idle position of the impact mechanism unit.

[0010] This enables safe and robust impact operation.

[0011] Preferably, a bearing element associated with the impact means guide element is designed to close the at least one recess in the load position and to release it in the idle position.

[0012] This allows the load position and the idle position to be realized easily and simply.

[0013] According to one embodiment, the piston element is designed to act on the impact means guide element in a direction away from the tool holder, wherein the piston element has a radial extension on its outer circumference or the impact means guide element has a radial extension on its inner circumference.

[0014] This makes it easy to operate impact operations.

[0015] Preferably, the impact means guide element is assigned a return device which is designed as a compression spring and / or forced driving element.

[0016] This enables safe and reliable resetting of the impact guide element.

[0017] Preferably, the piston element is mounted in the tool holder at its end facing away from the impact means.

[0018] This makes it easy and uncomplicated to store the piston element.

[0019] According to one embodiment, a damping mechanism is provided which is associated with the striking means and / or the striking means guide element.

[0020] This makes it possible to achieve damping in a simple way, at least to reduce vibrations.

[0021] Preferably, an elastomer part is assigned to the damping mechanism.

[0022] This makes it easy and straightforward to achieve an efficient damping effect. Short description of the drawings

[0023] The invention is explained in more detail in the following description using exemplary embodiments illustrated in the drawings. They show: Fig. 1 a perspective view of a hand tool designed as a demolition hammer with a percussion unit, Fig. 2 a longitudinal section through the percussion unit of Fig. 1 with a striking means guide element movable relative to the tool holder, Fig. 3 a longitudinal section through the percussion unit of Fig. 1 and Fig. 2 with a damping mechanism, Fig. 4 a longitudinal section through the percussion unit of Fig. 1 to Fig. 3 with an alternative damping mechanism, and Fig. 5 a longitudinal section through the percussion unit of Fig. 1 to Fig. 4 with additional damping mechanisms. Description of the embodiments

[0024] In the figures, elements with the same or comparable function are provided with identical reference symbols and are described in detail only once.

[0025] Fig. 1 shows a handheld power tool 100 illustratively designed as a demolition hammer. However, it should be noted that the present invention is not limited to a demolition hammer. The handheld power tool 100 can alternatively be designed, for example, as a hammer drill and / or chipping hammer.

[0026] The handheld power tool 100 comprises a percussion unit 150 and a tool holder 140 designed to receive an insert tool 145, in particular a chisel insert tool. Furthermore, the handheld power tool 100 preferably has a main handle 117 and, for example, an auxiliary handle 116, via which the handheld power tool 100 can be held and guided by a user. The main handle 117 is illustratively U-shaped. The auxiliary handle 116 is also illustratively U-shaped.

[0027] The handheld power tool 100 further comprises a housing 110 in which a drive motor 120 is arranged. Preferably, the drive motor 120 is furthermore associated with an optional motor housing 125, which is illustratively arranged in the housing 110. The drive motor 120 is designed to drive the tool holder 140 and the insert tool 145 arranged therein.

[0028] In addition, the drive motor 120 is preferably designed to drive the impact mechanism unit 150. The impact mechanism unit 150 is assigned a percussion mechanism housing 155. The tool holder 140 for guiding at least one piston element (220 in Fig. 2) along a longitudinal axis 102 of the impact mechanism housing 155 in at least one operating state, preferably an impact operation of the hand-held power tool 100.

[0029] Fig. 2 shows the percussion unit 150 of Fig. 1 with the impact mechanism housing 155, in which at least one impact means 210 and a piston element 220 which can be acted upon by the impact means 210 for the impact drive of the insert tool 145 of Fig. 1 are arranged. In Fig. 2, a load position 203 of the impact mechanism unit 150 is shown in an illustrative upper image area and an idle position 204 of the impact mechanism unit 150 is shown in an illustrative lower image area.

[0030] Preferably, the piston element 220 is arranged to be guided in sections in the longitudinal direction 299 of the impact mechanism housing 155 in the tool holder 140. According to the invention, an impact means guide element 240 for guiding the impact means 210 is designed to be movable in the longitudinal direction 299 relative to the tool holder 140, i.e., movable relative to the tool holder 140. The impact means guide element 240 is preferably mounted in the impact mechanism housing 155 so as to be movable in the longitudinal direction 299.

[0031] According to one embodiment, the piston element 220 is designed to act on the impact means guide element 240 in a direction 295 directed away from the tool holder 140. For this purpose, the piston element 220 preferably has an extension in the direction of an arrow 201, or a radial extension 222, on its outer circumference 294, or the impact means guide element 240 has a radial extension (570 in Fig. 5).

[0032] Preferably, an end face 241 of the impact means guide element 240 is movable relative to an end face 209 of the tool holder 140, wherein in the idle position 204, a distance 289 is formed between the two end faces 209, 241, and in the load position 203, a distance 288 is formed between the two end faces 209, 241. The distance 288 is preferably greater than the distance 289. Illustratively, the radial extension 222 of the piston element 220 is arranged between the two end faces 209, 241.

[0033] Furthermore, the piston element 220 has a diameter 228 at the position of the radial extension 222, and the impact means guide element 240 has an inner diameter 245. According to one embodiment, the diameter 228 is larger than the inner diameter 245. Furthermore, the impact means 210 has a diameter 275. Preferably, the diameter 275 is adapted to the inner diameter 245 in order to at least substantially reduce any possible radial play. It is noted that in Fig. 2 only one half of the diameter 228 of the rotationally symmetrical piston element 220 is shown at the position of the radial extension 222 and the diameter 275 of the rotationally symmetrical impact means 210.

[0034] Furthermore, the impact means guide element 240 illustratively has at least one recess 242, which is preferably closed in the loaded position 203 of the impact mechanism unit 150 to form an air spring 280 and is open in the idle position 204 of the impact mechanism unit 150. For this purpose, a bearing element 230 associated with the impact means guide element 240 is preferably designed to close the at least one recess 242 in the loaded position 203 and to release it in the idle position 204. The bearing element 230 is preferably arranged coaxially with the impact means guide element 240. In particular, the bearing element 230 is illustratively arranged on an outer circumference of the impact means guide element 240.

[0035] When an impact is generated, the preferably mechanically driven piston element 220 is coupled to the impact means 210 by an air cushion or by the air spring 280. The air spring 280 is located, as described above, in the impact means guide element 240 between the piston element 220 and the impact means 210. In the load case, the air spring 280 is closed to the outside, or the recess 242 is closed.

[0036] Under load, the impact device 210 periodically strikes the piston element 220, which is then applied to the insert tool 145. This so-called "impact chain" is rigidly coupled. Damping the impact generation is counterproductive.

[0037] In addition, a return device 224 is preferably assigned to the impact means guide element 240. The return device 224 is preferably designed to move the impact means guide element 240 from the load position 203, illustrated in the upper part of the image, to the idle position 204, illustrated in the lower part of the image. The return device 224 is preferably designed as a compression spring 232 and / or positive drive element 281. For this purpose, the return device 224, designed as a compression spring 232, is preferably compressed in the load position 203 and relaxed in the idle position 204. The compression spring 232 is preferably arranged coaxially to the impact means guide element 240. In particular, the compression spring 232 is preferably arranged on an outer circumference of the impact means guide element 240.

[0038] According to one embodiment, the positive drive element 281 is arranged at an end 227 facing the impact means 210, preferably at an end face of the piston element 220. The impact means guide element 240 has, for example, a drive element 226 on its end face 241 facing the piston element 220. The drive element 226 and the positive drive element 281 are connectable to one another. The impact means guide element 240 is coupled to the piston element 220, whereby the impact means guide element 240 and the piston element 220 move illustratively to the right during the transition from idle operation to load operation.

[0039] Preferably, the piston element 220 is mounted in the tool holder 140 at its end facing away from the impact mechanism 210. The tool holder 140 is illustrated by way of a bearing point 207 in the impact mechanism housing 155. Furthermore, the impact mechanism guide element 240 is preferably mounted by way of a bearing point 208 in the impact mechanism housing 155.

[0040] Fig. 3 shows the percussion unit 150 of Fig. 1 and Fig. 2, wherein preferably at least one damping mechanism 310 (430 in Fig. 4; Fig. 522, Fig. 524, Fig. 530, Fig. 550 in Fig. 5) is provided, which is assigned to the impact means 210 and / or the impact means guide element 240. Illustratively, the damping mechanism 310 is assigned to the impact means guide element 240. Preferably, the damping mechanism 310 is an elastomer part.

[0041] The impact means guide element 240 preferably has at least one coupling element 340 for coupling to the tool holder 140 in the circumferential direction 298 and / or in the longitudinal direction 299. Furthermore, the damping mechanism 310 preferably forms a guide 350 with the tool holder 140. For this purpose, the tool holder 140 preferably has a coupling element 340. The coupling element 340 illustratively has an inner receptacle 349, and the piston element 220 has an outer circumference 399, wherein the damping mechanism 310 is arranged in the radial direction or perpendicular to the longitudinal direction 299 between the outer circumference 399 and the inner receptacle 349.

[0042] The impact means 210, the piston element 220, and the insert tool 145 are held in a radial position or guided axially by mechanical components. The insert tool 145 and the piston element 220 are guided by the tool holder 140, and the impact means 210 is guided by the impact means guide element 240. A radial mounting of the impact means guide element 240 in the housing 155 preferably reduces the transmission of vibrations, thereby dampening vibrations. This is preferably done at the internal receptacle 349.

[0043] During the transition from load operation to idle operation, the impact means 210 preferably pushes the impact means guide element 240 in the longitudinal direction 299 toward the piston element 220. Illustratively, the impact means 210 has an edge 362, and the impact means guide element 240 has an edge 361 on the damping mechanism 310 associated with the edge 362. During the transition from idle operation to load operation, the edge 362 associated with the impact means guide element 240 preferably acts on the edge 361 associated with the damping mechanism 310. During load operation, there is no contact.

[0044] Furthermore, the impact means 210 illustratively has a section 370 facing the piston element 220, wherein the section 370 has a diameter 371. The diameter 371 is smaller than that of Fig. 2 described diameter 275 of the impact means 210. In addition, the piston element 220 has, for example, a section 390 facing the section 370. The section 390 has a diameter 391. The diameter 391 is preferably smaller than that in Fig. 2 described diameter 228 of the piston element 220. Preferably, the diameters 371, 391 of the sections 370, 390 are the same size.

[0045] Fig. 4 shows the percussion unit 150 of Fig. 1 to Fig. 3 with the whipping agent 210 of Fig. 3 and with a damping mechanism 430. The damping mechanism 430 is preferably U-shaped. The damping mechanism 430 is illustratively arranged on the radial extension 222 of the piston element 220.

[0046] Furthermore, Fig. 4, the impact means guide element 240 has, for example, a stop edge 442, which, in the case of a load, acts on the damping mechanism 430 along an arrow 490. Furthermore, the damping mechanism 430 illustratively strikes a front side 441 of the tool holder 140 during the transition from loaded operation to idle operation. Optionally, the impact means guide element 240 can also have a damping mechanism on its stop edge 442.

[0047] In the transition from the load case to the idle case, all parts of the impact chain, ie the impact guide element 240, the impact means 210, the piston element 220 and the insert tool 145 move from Fig. 2 in the direction of arrow 490, illustratively to the left. The damping mechanism 430 is provided for this forward movement of the piston element 220, which dampens the piston element 220 toward the end face 441.

[0048] Alternatively or optionally, a further damping mechanism can be arranged on the tool holder 140 and / or the impact means guide element 240.

[0049] Under load, the user of the handheld power tool 100 presses the handheld power tool 100 against a workpiece to be machined, e.g., a wall, thereby forcing the insert tool 145 into the handheld power tool 100. The piston element 220 is thereby forced to the right of the handheld power tool 100 and against the impact guide element 240. This causes the load-bearing position. This has nothing to do with the hard coupling of the impact chain under load. The interfaces between the piston element 220, the impact guide element 240, and the housing 155 are dampened in the axial direction by the damping mechanism 430.

[0050] Fig. 5 shows the percussion unit 150 of Fig. 1 to Fig. 4 with the impact means 210 and the piston element 220 of Fig. 3. In this case, further damping mechanisms 522, 524, 530, 550 can be assigned to the impact means guide element 240.

[0051] For example, a damping mechanism 522 is designed as a load impact damper and / or a damping mechanism 524 is designed as an idle impact damper. For this purpose, the impact means guide element 240 preferably has a web 570 on its inner circumference. The damping mechanism 522 is arranged illustratively to the left of the web 570, and the damping mechanism 524 is arranged illustratively to the right of the web 570. A load impact is preferably dampened at an end face 599 of the piston element 220 and at the damping mechanism 522. An idle impact is preferably dampened at an end face 598 and at the damping mechanism 524. An inner circumference of the damping mechanisms 522, 524 is at least substantially adapted to the diameters 391, 371 of the sections 390, 370. Furthermore, the web 570 and the damping mechanism 522 preferably form the positive driving element 281 according to a further embodiment.If the piston element 220 is acted upon illustratively to the right during the transition from the idle case to the load case, the end face 599 of the damping element 522, which is connected to the impact means guide element 240, is acted upon and the impact means guide element 240 is also acted upon illustratively to the right.

[0052] Furthermore, or alternatively, the impact means guide element 240 preferably has a damping mechanism 550 on its outer circumference, which is designed as a vibration damper. Damping the impact means 210 in the impact means guide element 240 in the radial direction preferably reduces the transmission of vibrations. This is preferably achieved via the damping mechanism 550. The damping mechanism 550 is arranged perpendicular to the longitudinal direction 299 between the bearing element 230 and the impact means guide element 240.

[0053] Furthermore, the impact means guide element 240 preferably has a circumferential collar 560 on its outer circumference, to which a damping mechanism 530 is also illustratively assigned.

[0054] It is pointed out that in the Fig. 3 to 5 only an illustrative upper half of the rotationally symmetrical percussion unit 150 is shown, so that only one half of the diameters 228, 245, 275, 371, 391 is shown.

Claims

[1] Hand-held power tool (100), in particular a demolition hammer, drill hammer or chisel hammer, with a tool holder (140) for receiving an insert tool (145) and a housing (110) in which a drive motor (120) and an impact mechanism unit (150) driven by the drive motor (120) are arranged, wherein the impact mechanism unit (150) is assigned at least one impact mechanism housing (155) in which at least one impact means (210) and a piston element (220) which can be acted upon by the impact means (210) for the impact drive of the insert tool (145) are arranged, characterized by that the piston element (220) is arranged to be guided in sections in the tool holder (140) in the longitudinal direction (299) of the impact mechanism housing (155), and an impact means guide element (240) for guiding the impact means (210) in the longitudinal direction (299) is designed to be movable relative to the tool holder (140). [2] Hand tool according to claim 1, characterized bythat the impact means guide element (240) is mounted in the impact mechanism housing (155) so as to be movable in the longitudinal direction (299). [3] Hand tool according to claim 1 or 2, characterized by that the impact means guide element (240) has coupling elements for coupling to the tool holder (140) in the circumferential direction (298). [4] Hand tool according to one of the preceding claims, characterized by that the impact means guide element (240) has at least one recess (242) which is closed in a load position (203) of the impact mechanism unit (150) to form an air spring (280) and is open in an idle position (204) of the impact mechanism unit (150). [5] Hand tool according to claim 4, characterized by that a bearing element (230) assigned to the impact means guide element (240) is designed to close the at least one recess (242) in the load position (203) and to release it in the idle position (204). [6] Hand tool according to one of the preceding claims, characterized by that the piston element (220) is designed to act on the impact means guide element (240) in a direction (295) directed away from the tool holder (140), wherein the piston element (220) has a radial extension (222) on its outer circumference (294) or the impact means guide element (240) has a radial extension (570) on its inner circumference (293). [7] Hand tool according to one of the preceding claims, characterized by that the impact means guide element (240) is assigned a return device (224) which is designed as a compression spring and / or forced driving element. [8] Hand tool according to one of the preceding claims, characterized by that the piston element (220) is mounted in the tool holder (140) at its end facing away from the impact means (210). [9] Hand tool according to one of the preceding claims, characterized by that a damping mechanism (310; 430; 522, 524, 530, 550) is provided which is associated with the striking means (210) and / or the striking means guide element (240). [10] Hand tool according to claim 9, characterized by that an elastomer part is assigned to the damping mechanism (310; 430; 522, 524, 530, 550).

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