Hand tool with a percussion unit and a damping element

Abstract

In a hand-held power tool, in particular a hammer drill and / or chisel hammer, with a percussion unit having at least one striker and one impact means, and with a damping element (250) for damping a B-impact against the impact means, the damping element (250) has a first damping region (251) and a second damping region (252), wherein the damping element (250) has a first spring rate along a predetermined damping path (399) in a damping case and has a second spring rate after exceeding the predetermined damping path (399), and wherein the first spring rate is smaller than the second spring rate.

Description

State of the art

[0001] The present invention relates to a hand-held power tool, in particular a hammer drill and / or chisel hammer, with a percussion unit having at least one striker and one impact means, and with a damping element for damping a B-impact against the impact means.

[0002] Such a handheld power tool, designed as a hammer drill, is known from the prior art. The handheld power tool comprises a percussion unit that includes at least one striker and a percussion element. Furthermore, the handheld power tool comprises a damping element for dampening a B-shaped impact against the percussion element. Disclosure of the invention

[0003] The invention relates to a handheld power tool, in particular a hammer drill and / or chisel hammer, comprising a percussion unit having at least one striker and a percussion element, and comprising a damping element for damping a B-impact against the percussion element. The damping element has a first damping region and a second damping region. In a damping case, the damping element has a first spring rate along a predetermined damping path and a second spring rate after exceeding the predetermined damping path, and wherein the first spring rate is smaller than the second spring rate.

[0004] The invention thus enables the provision of a handheld power tool with a damping element for damping a B-impact against an associated impact device, in which the two different spring rates can provide a comparatively soft damping element. Thus, during operation, when a B-impact occurs, the transmission of vibrations to the housing of the handheld power tool and thus to the user of the handheld power tool can be at least reduced.

[0005] Preferably, the first damping region has a first cross-sectional area and the second damping region has a second cross-sectional area, wherein the first cross-sectional area is smaller than the second cross-sectional area.

[0006] This allows the first and second spring rates to be provided easily and simply.

[0007] Preferably, the second damping region has an annular base body and the first damping region is arranged on an end face of the second damping region, wherein the first damping region is designed as an extension element formed along a longitudinal extent of the damping element.

[0008] Thus, the damping element with the first and second damping areas can be formed in a simple manner.

[0009] The extension element preferably has at least one web formed in sections in the circumferential direction of the damping element.

[0010] This allows a stable and robust extension element to be provided.

[0011] According to one embodiment, the at least one web has an oval base area or is conical along a longitudinal extent of the damping element.

[0012] Thus, an alternative design of at least one web can be made possible in a simple manner.

[0013] According to one embodiment, a plurality of webs are provided which are arranged evenly or unevenly distributed in the circumferential direction of the damping element.

[0014] This enables application-specific training with a suitable spring rate.

[0015] Preferably, the impact mechanism unit comprises a hammer tube and the damping element is arranged on an outer circumference of the hammer tube.

[0016] This allows for a simple and uncomplicated arrangement of the damping element.

[0017] According to one embodiment, the damping element is arranged along a longitudinal extension of the hammer tube between a spacer sleeve assigned to the impact mechanism unit and a control sleeve assigned to the impact mechanism unit.

[0018] This enables safe and reliable B-shock damping.

[0019] Preferably, the spacer sleeve has a receptacle on its end face facing the damping element for accommodating the second damping area in sections.

[0020] This enables a compact arrangement of the damping element on the spacer sleeve of the impact mechanism unit.

[0021] The damping element preferably comprises elastomer.

[0022] This makes it easy to provide a suitable material for the damping element. 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 schematic view of a hand-held power tool with a percussion unit, Fig. 2 a longitudinal section through the impact mechanism unit of the hand tool of Fig. 1 with a damping element, Fig. 3 a longitudinal section through the damping element of Fig. 2 and by a spacer sleeve and control sleeve assigned to the impact mechanism unit according to Fig. 2, Fig. 4 a perspective view of the damping element of Fig. 2 and Fig. 3 with bridges, Fig. 5 a perspective view of the damping element of Fig. 2 to Fig. 4 with an alternative design and number of webs, and Fig. 6 a perspective view of the damping element of Fig. 2 to Fig. 5 with a further design of the bridges. 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 hand-held power tool 100, designed as a drilling and / or chisel hammer, comprising a housing 105 in which a drive motor 120 is arranged. The drive motor 120 is designed to drive a tool holder 140 or an insert tool (299 in Fig. 2). Furthermore, the drive motor 120 is preferably associated with a percussion unit 130, wherein the drive motor 120 is also configured to drive the percussion unit 130.

[0026] The housing 105 illustratively has a handle 115 on which an operating element 117 for activating and deactivating the drive motor 120 is arranged. Illustratively, the handheld power tool 100 has a power cable 190 for mains-connected power supply. Alternatively, the handheld power tool 100 can also be designed to be mains-independent with a battery pack. For example, an optional additional handle 119 is arranged on the handheld power tool 100.

[0027] Fig. 2 shows the tool holder 140 as well as the housing 105 of the hand tool 100 of Fig. 1 arranged percussion unit 130 of Fig. 1, which comprises a hammer tube 210, a striker 260, and a striking means 270, for example in the form of a firing pin. An insert tool 299 is arranged in the tool holder 140.

[0028] The striker 260 and the impact means 270 are movably guided in the hammer tube 210. The impact means 270 is arranged behind the striker 260 along a longitudinal extension 203 of the hammer tube 210, as viewed toward the tool holder 140. The momentum of an impact generated by the impact mechanism unit 130 is transmitted from the striker 260 to the impact means 270 and from the impact means 270 to a tool shank of the insert tool 299.

[0029] In an impact operation of the impact unit 130 or the hand tool 100 of Fig. 1, after the impulse of the impact is transmitted, the impact means 270 experiences a so-called B-impact, i.e., an impact directed opposite to the impact of the impact means 270 on the tool shaft of the insert tool 299. This creates a counter-impulse from the tool shaft of the insert tool 299 to the impact means 270. To dampen the B-impact of the impact means 270, a damping element 250 is provided for the impact means 270. Illustratively, the damping element 250 is arranged on an outer circumference 211 of the hammer tube 210, but can alternatively also be arranged at any other location to dampen the impact means 270 during a B-impact.

[0030] According to the invention, the damping element 250 has a first damping region 251 and a second damping region 252. In a damping case, the damping element 250 has a first damping region 251 and a second damping region 252 along a predetermined damping path (399 in Fig. 3) a first spring rate on and after exceeding the specified damping travel (399 in Fig. 3) The damping element 250 has a second spring rate. Preferably, the first spring rate is smaller than the second spring rate.

[0031] The second damping region 252 preferably has an annular base body or is formed by such an annular base body, and the first damping region 251 is arranged or formed on an end face 253 of the second damping region 252. The first damping region 251 is preferably designed as an extension element 259 formed along a longitudinal extent 201 of the damping element 250. The end face 253 of the second damping region 252 is preferably arranged facing the tool holder 140. As a result, the first damping region 251 is arranged facing the tool holder 140 and the second damping region 252 is arranged facing away from the tool holder 140.

[0032] According to one embodiment, the damping element 250 is arranged along the longitudinal extension 203 of the hammer tube 210 between a spacer sleeve 230 assigned to the impact mechanism unit 130 and a control sleeve 240 assigned to the impact mechanism unit 130. Preferably, the spacer sleeve 230 has a receptacle (232 in Fig. 3) for sectionally receiving the second damping area 252.

[0033] The control sleeve 240 preferably has a circumferential collar 242 facing the second damping region 252, wherein the second damping region 252 is illustratively adjacent to an end face 241 of the circumferential collar 242. Furthermore, the control sleeve 240 is assigned, by way of example, a spring element 220 which is designed to counteract a displacement of the control sleeve 240.

[0034] According to one embodiment, the damping element 250 is formed integrally with the first and second damping regions 251, 252. The damping element 250 preferably comprises an elastomer. The damping element 250 preferably comprises the same material, preferably an elastomer, in the first and second damping regions 251, 252. According to another embodiment, the damping element 250 is formed in multiple parts, with the first and second damping regions 251, 252 being fastened to one another. Alternatively, the two damping regions 251, 252 can comprise different materials.

[0035] Fig. 3 shows the damping element 250, the spacer sleeve 230 and the control sleeve 240 of Fig. 2. This illustrates Fig. 3 shows the design of the damping element 250 with the first and second damping regions 251, 252. The first damping region 251 preferably has a length 257 and a thickness 255, and the second damping region 252 has a length 256 and a thickness 254. The first thickness 255 is preferably smaller than the second thickness 254. Furthermore, the first length 257 is preferably smaller than the second length 256. It should be noted that the thicknesses 254, 255 are illustratively formed in the radial direction of the damping element 250, and the lengths 256, 257 are illustratively formed along the longitudinal extent 201 of the damping element 250.

[0036] Preferably, the spacer sleeve 230 has a receptacle 232 on its end face 231 facing the damping element 250 for partially receiving the second damping region 252. Preferably, the extension element 259 of the damping element 250 has at least one web 351 formed in sections in the circumferential direction 301 of the damping element 250. Illustratively, a plurality of webs 351 are provided, which are arranged evenly or unevenly distributed in the circumferential direction 301 of the damping element 250.

[0037] In a damping case, the damping element 250 preferably has the first spring rate along a predetermined damping path 399 and has the second spring rate after exceeding the predetermined damping path 399. As described above, the first spring rate is smaller than the second spring rate. The damping path 399 is preferably formed as a distance between the end face 231 of the spacer sleeve 230 and the end face 253 of the first damping region 251 facing the end face 231.

[0038] To form the first and second spring rates, the first damping region 251 illustratively has a first cross-sectional area 388, and the second damping region 252 has a second cross-sectional area 389. Preferably, the first cross-sectional area 388 is smaller than the second cross-sectional area 389.

[0039] Fig. 4 shows the damping element 250 of Fig. 2 and Fig. 3 with an alternative design of the webs 351. Fig. 4 the annular base body of the second damping region 252 and the first damping region 251 arranged on the end face 251 of the second damping region 252. As described above, the first damping region 251 is designed as an extension element 259 with webs 351.

[0040] At least one, and illustratively all eight, webs 351 have an oval base surface 411. The oval base surface 411 is preferably arranged in the circumferential direction 301. Alternatively, the oval base surface 411 can also be arranged rotated, e.g., by 90°.

[0041] Fig. 5 shows the damping element 250 of Fig. 2 to Fig. 4 with a further embodiment of the webs 351. The first damping region 251 illustratively has four webs 351. The webs 351 preferably have ribs 510, 520 on their inner side 501 and / or outer side 502. Illustratively, the webs 351 each have a plurality of ribs 510, 520 on their inner side 501 and their outer side 502.

[0042] Fig. 6 shows the damping element 250 of Fig. 2 to Fig. 5 with a further alternative design of the webs 351. The first damping region 251 again illustratively has eight webs 351, which are now conical along the longitudinal extent 201 of the damping element 250.

[0043] It should be noted that the first damping region 251 or the webs 351 can also have any other shape. Furthermore, the first damping region 251 can also be annular.

Claims

[1] Hand tool (100), in particular a drilling and / or chisel hammer, with a percussion unit (130) which has at least one striker (260) and a striking means (270), and with a damping element (250) for damping a B-impact against the striking means (270), characterized by in that the damping element (250) has a first damping region (251) and a second damping region (252), wherein the damping element (250) has a first spring rate along a predetermined damping path (399) in a damping case and has a second spring rate after exceeding the predetermined damping path (399), and wherein the first spring rate is smaller than the second spring rate. [2] Hand tool according to claim 1, characterized bythat the first damping region (251) has a first cross-sectional area (388) and the second damping region (252) has a second cross-sectional area (389), wherein the first cross-sectional area (388) is smaller than the second cross-sectional area (389). [3] Hand tool according to claim 1 or 2, characterized by in that the second damping region (252) has an annular base body and the first damping region (251) is arranged on an end face (253) of the second damping region (252), wherein the first damping region (251) is designed as an extension element (259) formed along a longitudinal extent (201) of the damping element (250). [4] Hand tool according to claim 3, characterized by that the extension element (259) has at least one web (351) formed in sections in the circumferential direction (301) of the damping element (250). [5] Hand tool according to claim 4, characterized bythat the at least one web (351) has an oval base area (411) or is conical along a longitudinal extent (201) of the damping element (250). [6] Hand tool according to claim 4 or 5, characterized by that a plurality of webs (351) are provided which are arranged uniformly or unevenly distributed in the circumferential direction (301) of the damping element (250). [7] Hand tool according to one of the preceding claims, characterized by that the impact mechanism unit (130) has a hammer tube (210) and the damping element (250) is arranged on an outer circumference (211) of the hammer tube (210). [8] Hand tool according to claim 7, characterized by that the damping element (250) is arranged along a longitudinal extension (203) of the hammer tube (210) between a spacer sleeve (230) assigned to the impact mechanism unit (130) and a control sleeve (240) assigned to the impact mechanism unit (130). [9] Hand tool according to claim 8, characterized by that the spacer sleeve (230) has, on its end face (231) facing the damping element (250), a receptacle (232) for sectionally receiving the second damping region (252). [10] Hand tool according to one of the preceding claims, characterized by that the damping element (250) comprises elastomer.

Images