hand-held power tool with a mechanical rotary impact mechanism

Abstract

A hand-held power tool (100) with a mechanical rotary impact mechanism (122) for the impact drive of a tool (140), wherein the rotary impact mechanism (122) has a spring-loaded impact body (225) which is coupled to the rotary drive with an associated drive shaft (120) and is axially displaceable on the drive shaft (120), characterized in that the impact body (225) is spring-loaded by at least one spring element (228; 510) which has at least two different spring constants (Fc1, Fc2), wherein the at least one spring element (228) is designed in the manner of a spring system (605; 705) with at least two individual spring elements (610, 620; 720, 730), wherein the individual spring elements (610, 620) have different spring constants (Fc1, Fc2), characterized in that the at least two individual spring elements (610, 620;720, 730) are arranged in parallel to each other, wherein, in a starting position of the striking body (225), when the at least two individual spring elements (610, 620) are arranged in parallel, a first individual spring element (610) rests against the striking body (225) and a second individual spring element (620) is arranged spaced apart from the striking body (225) by a predetermined distance (630).

Description

State of the art

[0001] The present invention relates to a hand-held power tool with a mechanical rotary impact mechanism for the impact drive of an insert tool, wherein the rotary impact mechanism has a spring-loaded impact body which is coupled to the rotary drive with an associated drive shaft and is mounted axially displaceable on the drive shaft.

[0002] A hand-held power tool of this type is known from the prior art, featuring a rotary impact mechanism with a spring-loaded impact body. The impact body is spring-loaded by a compression spring element with a predetermined spring constant, constant spring diameter, and constant coil spacing. With a relatively small spring constant, the impact body experiences a low preload, which can, however, generate a high recoil force, potentially causing disruptive vibrations. Conversely, with a relatively large spring constant, the impact body experiences a high preload, which can transmit vertical impacts and / or impacts to the edges of the impact body or the drive shaft coupled to the impact body, thereby increasing wear on the rotary impact mechanism.

[0003] In particular, from DE 10 2010 062 014 B3 a hand-held power tool with a percussion mechanism is known, which has a spring system with two parallel individual springs that are clamped between two stops.

[0004] DE 10 2009 015 732 A1 discloses a percussion mechanism for a hand-held power tool, which includes springs connected in series.

[0005] From DE 10 2009 015 730 A1 of the same applicant, a percussion mechanism for a hand-held machine tool with leaf springs connected in series is also known.

[0006] DE 10 2007 003 037 A1 shows an impact wrench with an impact body and a single conical spring acting on it.

[0007] DE 10 2009 046 348 A1 discloses a damping device suitable for damping vibrations, particularly in hand-held power tools, and a method for its manufacture. Disclosure of the invention

[0008] The present invention provides a new hand-held power tool with a mechanical rotary impact mechanism for driving a tool, wherein the rotary impact mechanism comprises a spring-loaded impact body which is coupled to the rotary drive via an associated drive shaft and is axially displaceable on the drive shaft. The impact body is spring-loaded by at least one spring element which has at least two different spring constants.

[0009] The invention thus enables the provision of a hand-held power tool which, by using at least one spring element with at least two different spring constants, can at least approximately reduce excessive axial displacement of the impact body and / or excessive restoring force that forces the impact body into an associated starting position, so that permanent damage or destruction of the rotary impact mechanism can at least approximately be prevented.

[0010] The at least one spring element is preferably designed in the form of a conical spring. This allows for a stable and robust spring element with two different spring constants.

[0011] According to the invention, the at least one spring element is designed as a spring system with at least two individual spring elements, wherein the individual spring elements have different spring constants. Thus, the at least one spring element can be implemented in a simple manner using a spring system.

[0012] According to the invention, the at least two individual spring elements are arranged in parallel or series with respect to each other. This enables a reliable and uncomplicated arrangement of the individual spring elements in the spring system.

[0013] The at least two individual spring elements are preferably arranged one inside the other in parallel. This allows for a compact and robust arrangement of the two individual spring elements.

[0014] According to the invention, when at least two individual spring elements are connected in parallel, in a starting position of the striking body, a first individual spring element is in contact with the striking body, and a second individual spring element is preferably arranged at a predetermined distance from the striking body. This enables a two-phase impact on the striking body, in which, after compression of the first individual spring element by the predetermined distance, the spring constant of the first individual spring element is at least partially increased by the spring constant of the second individual spring element.

[0015] The at least two individual spring elements are preferably connected to each other via an intermediate element when connected in series. This ensures a robust and secure connection between the two individual spring elements.

[0016] According to one embodiment, the intermediate element is provided with an adjustment mechanism for setting an initial spring constant. This allows for the simple and reliable provision of a rotary impact mechanism for different applications, e.g., for different materials with varying hardness.

[0017] Preferably, the adjustment mechanism for setting the initial spring constant includes a spring-loaded locking element. This allows for an adjustable initial spring constant, which preferably has a comparatively large value.

[0018] Preferably, the at least one spring element and / or the at least two individual spring elements each have a constant or variable spring diameter and / or a constant or variable winding spacing. This allows for the simple and straightforward provision of a desired or required spring constant for the spring element or individual spring elements.

[0019] Furthermore, the present invention provides a mechanical rotary impact mechanism for a hand-held power tool for the impact driving of a tool attachment, wherein the rotary impact mechanism comprises a spring-loaded impact body which can be coupled to an associated drive shaft of the hand-held power tool for rotary drive and is axially displaceable on the drive shaft. The impact body is spring-loaded by at least one spring element which has at least two different spring constants. Brief description of the drawings

[0020] The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. The drawings show: Fig. 1 A schematic view of a hand-held power tool with a mechanical rotary impact mechanism according to one embodiment, Fig. 2 a sectional view of a proximal section of the mechanical rotary impact mechanism of the hand-held power tool of Fig. 1, Fig. 3 A sectional view of a distal section of the mechanical rotary impact mechanism of the hand-held power tool of Fig. 1 and Fig. 2, Fig. 4 a schematic spring force-spring travel measurement diagram of a spring element according to the invention of the mechanical rotary impact mechanism of Fig. 1, Fig. 2 to Fig. 3, Fig. 5a a sectional view of the mechanical rotary impact mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring element according to a first embodiment, which approximately corresponds to the spring force-spring travel measurement diagram of Fig. 4 corresponds, in a first version variant, Fig. 5b a sectional view of the mechanical rotary striking mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring element according to a first embodiment, in a second embodiment variant, Fig. 6a a sectional view of the mechanical rotary striking mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring system according to a first embodiment, Fig. 6b a sectional view of the mechanical rotary striking mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring system according to a second embodiment, Fig. 7a a sectional view of the mechanical rotary striking mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring system according to a third embodiment, Fig. 7b a sectional view of the mechanical rotary striking mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring system according to a fourth embodiment, Fig. 7c an exemplary spring force-travel measurement diagram of the spring system of Fig. 6 and Fig. 7, Fig. 8a a sectional view of the mechanical rotary striking mechanism of Fig. 1, Fig. 2 to Fig. 3 with a spring system and an adjustment mechanism for setting an initial spring constant, Fig. 8b an exemplary spring force-travel measurement diagram of the spring system of Fig. 8a, Fig. 9a a perspective side view of a first exemplary spring element, Fig. 9b a perspective side view of a second exemplary spring element, Fig. 9c a perspective side view of a third exemplary spring element, and Fig. 9d a perspective side view of a fourth exemplary spring element. Description of the exemplary implementations

[0021] Fig. Figure 1 shows a hand-held power tool 100 equipped with a tool holder 150 and a housing 110 with a handle 126. According to one embodiment, the hand-held power tool 100 can be mechanically and electrically connected to a battery pack 130 for mains-independent power supply.

[0022] The housing 110 contains an electric drive motor 114, powered by the battery pack 130, a gearbox 118, and a mechanical impact mechanism 122. The drive motor 114 can be operated, for example, via a hand switch 128, i.e., switched on and off, and can be any type of motor, such as an electronically commutated motor or a DC motor. Preferably, the drive motor 114 is electronically controllable such that both reversing operation and setting a desired rotational speed are possible. The operation and construction of a suitable drive motor are sufficiently known from the prior art, so a detailed description is omitted here for the sake of brevity.

[0023] The drive motor 114 is connected to the gearbox 118 via an associated motor shaft 116. The gearbox converts the rotation of the motor shaft 116 into the rotation of a drive shaft 120 located between the gearbox 118 and the impact mechanism 122. This conversion preferably occurs such that the drive shaft 120 rotates relative to the motor shaft 116 with increased torque but reduced rotational speed. For illustrative purposes, the drive motor 114 is arranged in a motor housing 115, and the gearbox 118 in a gearbox housing 119. The gearbox housing 119 and the motor housing 115 are, by way of example, arranged within the housing 110.

[0024] The mechanical impact mechanism 122 connected to the drive shaft 120 is, for example, a rotary impact mechanism that generates sudden, high-intensity rotational impulses and transmits them to an output shaft 124, e.g., an output spindle. The tool holder 150 is provided on the output shaft 124. This holder is preferably designed to accommodate insert tools and, according to one embodiment, can be connected to an insert tool 140 with an external polygonal coupling 142, as well as to an insert tool with an internal polygonal coupling. The insert tool 140 is, for example, designed as a screwdriver bit with the external polygonal coupling 142, illustratively an octagonal coupling. Such a screwdriver bit is sufficiently known from the prior art, so a detailed description is omitted here for the sake of brevity.

[0025] It is noted that the hand tool 100 is designed as an example of a cordless impact wrench. However, the present invention is not limited to cordless impact wrenches, but can rather be applied to various power tools in which the mechanical impact mechanism 122 can be used to generate impacts, e.g., in an impact drill, etc., regardless of whether the power tool can be operated independently of a battery pack or dependent on a mains connection.

[0026] Fig. Figure 2 shows a distal section of the transmission 118 arranged in the transmission housing 119. Fig. 1, as well as a proximal section of the mechanical rotary impact mechanism 122 of Fig. 1 according to one embodiment. This is shown for illustrative purposes in a housing part 222 which is attached to the gearbox housing 119.

[0027] The gearbox 118 is, by way of example, a planetary gearbox and has, for illustrative purposes, a sun gear 209, at least one planet gear 215, 217, a planet carrier or driver 218, and a ring gear 206 arranged axially and radially immovably in the gearbox housing 119. The sun gear 209 is, by way of example, rotatably mounted on the drive shaft 120 via a bearing assembly 219. The driver 218 is, for illustrative purposes, formed integrally with the drive shaft 120, e.g., molded onto it. Alternatively, the driver 218 can be connected to the drive shaft 120 via a suitable connecting device.

[0028] According to one embodiment, the planetary gear 118 can be switched between several stages and is shown for illustrative purposes as being switchable between a first and a second stage, wherein the first stage is formed by the sun gear 209, the at least one planet gear 215, 217, the planet carrier or driver 218, and the ring gear 206. A second stage 211 is only indicated for the sake of brevity and clarity of the drawing. However, it should be noted that a suitable planetary gear design is sufficiently familiar to those skilled in the art, so a detailed description is unnecessary here.

[0029] In a distal section of the gearbox housing 119, a bearing 234 designed as a ball bearing is arranged by way of example for supporting the drive shaft 120. However, it should be noted that other bearing types can also be used within the scope of the present invention. For example, the bearing 234 can alternatively be implemented as a plain bearing, needle roller bearing, roller bearing or as another type of rolling bearing.

[0030] According to one embodiment, a washer 240 associated with the mechanical rotary impact mechanism 122 is arranged on an end face 299 of the gearbox housing 119. This washer has an opening 242 and is rotatably and axially displaceably mounted on the drive shaft 120 via this opening. Furthermore, an impact element 225 is mounted at least axially displaceably on the drive shaft 120. Preferably, a damping element 244, mounted on the drive shaft 120 for illustrative purposes, is arranged between the impact element 225 and the washer 240. At least one spring element 228, exemplified as a compression spring, is also arranged to surround the drive shaft 120 for generating the impact during impact operation of the hand-held power tool 100. Fig. 1.

[0031] The at least one compression spring 228 rests against the washer 240 at its end 227 pointing away from the impact body 225. The washer 240 may be molded onto the compression spring 228, for example, by injection molding. Alternatively, the compression spring 228 and the washer 240 may be formed in one piece. An end 226 of the compression spring 228 facing the impact body 225 is arranged in the impact body 225, as shown below. Fig. 3 described.

[0032] According to one embodiment, the compression spring 228 is supported on the washer 240 and acts on the impact body 225 in a distal direction, i.e. in the direction of the tool holder 150. Fig. 1, as indicated by arrow 229. In normal operation of the hand-held power tool 100 of Fig. 1, i.e., if no impact generation is required, the impactor 225 rotates in a Fig. 2 shown distal end position with the drive shaft 120.

[0033] During the generation of an impact by the mechanical rotary impact mechanism 122 in the impact mode of the hand-held power tool 100 by Fig. 1. The striking element 225 is displaced axially in the proximal direction, i.e., towards the washer 240, against the force of the compression spring 228. To prevent excessive axial displacement of the striking element 225, it is blocked in a predetermined proximal end position by the damping element 244, which dampens any impact of the striking element 225 against the damping element 244. The striking element 225 is then abruptly returned to its original position by the compression spring 228 to generate the impact. Fig. The distal end position shown in Figure 2 is rebounded. Since the operation of a mechanical striking mechanism and the generation of impacts by such a mechanism are sufficiently known to those skilled in the art, a more detailed description is omitted here for the sake of brevity.

[0034] Fig. Figure 3 shows a distal section of the mechanical rotary impact mechanism 122 of Fig. 1 and Fig. 2 according to one embodiment, with the impact element 225 mounted on the drive shaft 120, which is acted upon by the compression spring 228 in the direction of the output shaft 124. This is rotatably coupled to the drive shaft 120 via a flange 324 provided with output cams.

[0035] According to one embodiment, the impact body 225 is cup-shaped, with an annular bottom section 398, the end face 330 of which faces the output shaft 124 during normal operation of the hand-held power tool 100. Fig. 1 abuts the flange 324. An inner, annular wall section 332 and an outer, annular wall section 334 are formed on the bottom section 398, which has a central opening 399, and which together with the bottom section 398 form a Fig. Form an annular groove 336 facing the compression spring 228.

[0036] The end 226 of the compression spring 228 facing the impact body 225 is arranged in the annular groove 336. For illustrative purposes, it rests against an annular disk 360, which may be attached to or integrally formed with the compression spring 228. The compression spring 228 exerts force on the annular disk 360 in the direction of the base section 398 and thus in the direction of the flange 324, preferably against a thrust ball bearing 350 arranged in the annular groove 336. This thrust ball bearing preferably has an approximately U-shaped support ring 352 in which a plurality of balls 354, 356 are arranged. The annular disk 360 rests against the support ring 352, and the balls 354, 356 thus rest against the base section 398.However, it should be noted that the ring disc 360 is only used to achieve an improved pressure distribution on the thrust ball bearing 350 and thus a design of the mechanical rotary impact mechanism 122 without the ring disc 360 is also possible, in which the end 226 of the compression spring 228 facing the impact body 225 rests directly against the thrust ball bearing 350.

[0037] According to one embodiment, the thrust ball bearing 350 is designed to prevent impact generation by the mechanical rotary impact mechanism 122 in impact mode of the hand-held power tool 100. Fig. 1. To enable rotation of the impact body 225 relative to the compression spring 228. In this case, the impact body 225 preferably rotates with the U-shaped support ring 352 of the thrust ball bearing 350 relative to the drive shaft 120, its balls 354, 356 rolling over the ring disk 360.

[0038] Fig. Figure 4 shows a spring force-spring travel measurement diagram of at least one compression spring 228 of the rotary impact mechanism 122. Fig. 1, Fig. 2 to Fig. 3, where, for illustrative purposes, the spring force F is plotted on an ordinate and the spring deflection s on an abscissa of the measurement diagram. Preferably, the compression spring 228 has at least two different spring constants Fc1, Fc2 with associated spring deflections s1 and s2, respectively, which are shown in Fig. 4 are characterized by a first region I and a second region II. These spring constants Fc1, Fc2 can preferably be adapted to the rotary impact mechanism 122 or an intended application, thus preventing excessive axial displacement of the impact body 225. Fig. 2 and Fig. 3 in impact operation and / or an excessive restoring force of the impact body 225 or an impact of the impact body 225 is at least approximately prevented.

[0039] For example, the first spring constant Fc1 is smaller than the second spring constant Fc2, so that in an application with low impact force or high impact velocity, preferably only the first spring constant Fc1 is used. This prevents excessive axial displacement of the striking body 225. In an application where a high impact force is required, both spring constants Fc1 and Fc2 are used, wherein the spring constant Fc1 preferably at least reduces and preferably prevents excessive axial displacement of the striking body 225, and / or the spring constant Fc2 preferably at least reduces and preferably prevents excessive restoring force of the striking body 225 or impact of the striking body 225. It should be noted that the arrangement of the two spring constants Fc1 and Fc2 in Fig. Paragraph 4 is merely exemplary and should not be seen as a limitation of the invention. For example, the spring constant Fc1 can also be greater than the spring constant Fc2.

[0040] By way of example, the first spring constant Fc1, illustrated in section I, exhibits an approximately linearly increasing or straight characteristic curve 401, and the second spring constant Fc2, illustrated in section II, exhibits an approximately exponentially increasing or progressive characteristic curve 402. It should be noted that the design of the spring constants Fc1 and Fc2, or their characteristic curves, are merely exemplary and are not to be seen as a limitation of the invention. Thus, the characteristic curves 401 and 402 of the compression spring 228 can have a straight, progressive, and / or degressive profile. Furthermore, the two characteristic curves 401 and 402 can also have the same profile; that is, the two characteristic curves 401 and 402 can, for example, have a straight profile with different slopes or spring constants.

[0041] Fig. Figure 5a shows the rotary impact mechanism 122 with an impact body 520 and the flange 324 mounted on the drive shaft 120. Fig. 3. According to one embodiment, the striking body 520 is analogous to the striking body 225 of Fig. 2, but with a comparatively shortened inner wall section 332. Furthermore, the compression spring 228 is designed in the manner of a conical spring 510 with a first wide end 512 and a second narrow end 514, which preferably corresponds to the spring force-displacement measurement diagram of Fig. 4 corresponding spring constants Fc1, Fc2. For illustrative purposes, the first end 512 of the spring 510 is the end 226 facing the striking body 520, which in Fig. 5a in the impact body 225 is arranged and preferably analogous to Fig. 3 rests against the ring disc 360. In addition, the second end 514 of the spring 510 rests against a support surface 522 of the drive shaft 120.

[0042] Fig. Figure 5b shows the rotary striking mechanism 122 with the striking body 520 and the conical spring 510 from Fig. 5a, wherein, according to a further embodiment, the second, narrow end 514 of the spring 510 is the end 226 facing the striking body 520. The second end 514 of the spring 510 is arranged in the striking body 225 and is preferably positioned analogously to Fig. 3 and Fig. 5a on the ring disc 360. Furthermore, the first end 512 of the spring 510 rests on the support surface 522 of the drive shaft 120.

[0043] Fig. Figure 6a shows the rotary striking mechanism 122 with the striking body 225 from Fig. 2 and the flange 324 mounted on the drive shaft 120 of Fig. 3 with the compression spring 228 designed according to a second embodiment of Fig. 2. The compression spring 228 is designed in the manner of a spring system 605 with at least two, for illustrative purposes a first and second individual spring element 610, 620, wherein the two individual spring elements 610, 620 have different spring constants Fc1, Fc2, which preferably correspond to the spring force-displacement measurement diagram of Fig. 4 correspond.

[0044] According to one embodiment, the two individual spring elements 610, 620 are arranged in parallel to each other, with the two individual spring elements 610, 620 being arranged one inside the other. In this case, Fig. 6a The second single spring element 620 is arranged within the first single spring element 610, the first single spring element 610 being arranged between the annular disk 360 of the impact body 225 and the support surface 522 of the drive shaft 120. Furthermore, the second single spring element 620 is arranged between the support surface 522 and an end 602 of the impact body 225 or of the inner wall section 332 facing the drive shaft 120.

[0045] Preferably, in a starting position of the striking body 225, the first individual spring element 610 rests against the striking body 225 or the annular disk 360, and the second individual spring element 620 is arranged at a predetermined distance 630 from the striking body 225 or the end 602 of the striking body 225. Preferably, the second individual spring element 620 has a larger spring constant Fc2 than the first individual spring element 610. Thus, during impact operation, the first individual spring element 610 is initially stressed and compressed, and after compression by the predetermined distance 630, both individual spring elements 610 and 620 are stressed, resulting in the following: Fig. 4 described an excessive axial displacement of the striking body 225 and / or an excessive restoring force of the striking body 225 or an impact of the striking body 225 can at least be reduced and preferably prevented.

[0046] Fig. Figure 6b shows the rotary striking mechanism 122 with the spring system 605 from Fig. 6a, wherein the first individual spring element 610 is arranged within the second individual spring element 620. The second individual spring element 620 is arranged between the support surface 522 and one end 602 of the impact body 225 or the outer wall section 334 facing the drive shaft 120 and rests against a support element 640 at its opposite end. The support element 640 is preferably designed in the form of an annular disk and is arranged on the support surface 522 of the drive shaft 120. Preferably, the first and / or second individual spring element 610, 620 can be integrally connected with the support element 640. However, the support element 640 can also be integrally connected with the drive shaft 120. Furthermore, the support element 640 can also be integrally formed with the drive shaft 120, the first and / or second individual spring element 610, 620. Analogously to Fig. 6a the second single spring element 620 preferably has a larger spring constant Fc2 than the first single spring element 610.

[0047] Fig. Figure 7a shows the rotary percussion mechanism 122 from Fig. 2 and Fig. 3 or of Fig. 6a and Fig. 6b with a spring system 705, which is provided with at least two, for illustrative purposes a first and second individual spring element 720, 730. The two individual spring elements 720, 730 preferably have different spring constants Fc1, Fc2, which preferably correspond to the spring force-displacement measurement diagram of Fig. 4 correspond. Here, the two individual spring elements 720, 730 are arranged in series with each other by way of example, with these one behind the other, in Fig. 7a are arranged one below the other for illustrative purposes.

[0048] According to one embodiment, the two individual spring elements 720, 730 are coupled to each other via an intermediate element 710. The first individual spring element 720 is arranged between the annular disk 360 of the impact body 225 and a side 711 of the intermediate element 710 facing the impact body 225, and the second individual spring element 730 is arranged between the support surface 522 of the drive shaft 120 and a side 712 of the intermediate element 710 facing the drive shaft 120. The intermediate element 710 is preferably designed in the form of an annular disk. Preferably, the first and / or second individual spring element 610, 620 can be integrally formed with or integrally connected to the intermediate element 710. Furthermore, the first individual spring element 720 preferably has a larger spring constant Fc1 than the second individual spring element 730.

[0049] Fig. Figure 7b shows the rotary striking mechanism 122 with the spring system 705 from Fig. 7a, wherein the second single spring element 730 is now arranged between the ring disk 360 of the impact body 225 and the side 711 of the intermediate element 710 facing the impact body 225, and wherein the first single spring element 720 is now arranged between the support surface 522 of the drive shaft 120 and the side 712 of the intermediate element 710 facing the drive shaft 120. The first single spring element 720 is arranged analogously to Fig. 7a preferably has a larger spring constant Fc1 than the second single spring element 730.

[0050] Fig. Figure 7c shows a spring force-travel measurement diagram of the spring system 705 from Fig. 7a and Fig. 7b, wherein, for illustrative purposes, an exemplary spring force F in Newtons is plotted on an ordinate and an exemplary spring deflection s in millimeters is plotted on an abscissa of the measurement diagram. Preferably, the spring system 705 has two different spring constants Fc1, Fc2 with associated spring deflections s1 and s2, respectively, which are shown in Fig. 7c analogous to Fig. 4 are characterized by a first region I and a second region II. Regardless of the arrangement of the individual spring elements 720, 730 or their spring constants Fc1, Fc2, preferably in impact operation the individual spring element with the smaller spring constant is stressed or compressed first and then the other individual spring element, or both individual spring elements are stressed together or simultaneously.

[0051] For example, the first spring constant Fc1, illustrated in section I, exhibits an approximately linearly increasing or straight characteristic curve 701, and the second spring constant Fc2, illustrated in section II, exhibits an approximately exponentially increasing or progressive characteristic curve 702. It should be noted that the values ​​shown for the spring constants Fc1, Fc2, and the associated spring deflections s1 and s2 are merely exemplary and are not to be considered a limitation of the invention.

[0052] Fig. Figure 8a shows the rotary striking mechanism 122 with the spring system 705 and the intermediate element 710 from Fig. 7a, wherein the intermediate element 710 is provided with an adjusting mechanism 810 for setting an initial spring constant according to one embodiment. The adjusting mechanism 810 for setting the initial spring constant has at least one spring-loaded locking element 820.

[0053] In impact mode of the rotary impact mechanism 122, the following is required: Fig. In the embodiment shown in Figure 8a, a high initial spring constant is achieved by pre-tensioning the illustrative first individual spring element 720 by the adjusting mechanism 810. The locking element 820 locks the second individual spring element 730, and upon exceeding a predetermined spring force, the locking element 820 unlocks the second individual spring element 730, or releases it, thereby making the spring constant Fc2 in region II preferably smaller than the spring constant Fc1 in region I, or having a smaller slope.

[0054] Fig. Figure 8b shows a spring force-travel measurement diagram of the spring system 705 from Fig. 8a with the adjustment mechanism 810, wherein, for illustrative purposes, an exemplary spring force F in Newtons is plotted on an ordinate and an exemplary spring deflection s in millimeters is plotted on an abscissa of the measurement diagram. According to the invention, the spring system 705 has two different spring constants Fc1, Fc2 with associated spring deflections s1 and s2, respectively, which are shown in Fig. 8b analogous to Fig. 4 and Fig. 7c are characterized by a first region I and a second region II. By way of example, a first spring constant Fc1, illustrated in the first region I, has an approximately linearly increasing or straight characteristic curve 801, which has a comparatively large slope due to the high initial spring constant, and a second spring constant Fc2, illustrated in the second region II, also has an approximately linearly increasing or straight characteristic curve 802, which has a comparatively small slope due to the locking element 820. It should be noted that the values ​​shown for the spring constants Fc1, Fc2, and the associated spring deflections s1 and s2 are merely exemplary and are not to be seen as a limitation of the invention. Furthermore, it should be noted that the configuration of the spring constants Fc1, Fc2, and s2 is subject to change.whose characteristic curves are also merely exemplary and are not to be seen as a limitation of the invention. Thus, the characteristic curves 801, 802 of the compression spring 228 can be analogous to the characteristic curves 401, 402 of . Fig. 4 and the characteristic curves 701, 702 of Fig. 7c, have a straight, progressive and / or degressive course.

[0055] The following Fig. Figures 9a to 9d show exemplary spring elements (910 in Fig. 9a, Fig. 920 in Fig. 9b, Fig. 930 in Fig. 9c, Fig. 940 in Fig. 9d) for the realization of the compression spring 228 and / or the individual spring elements 610, 620, 710, 720 of the spring system 705, each having a constant or variable spring diameter (D in Fig. 9a; D1, D2 in Fig. 9b and Fig. 9d) and / or a constant or variable winding spacing (h in Fig. 9a; h1, h2 in Fig. 9b and Fig. exhibit 9c).

[0056] Fig. Figure 9a shows a spring element 910 according to a first embodiment. The spring element 910 preferably has a constant spring diameter D and a constant winding spacing h.

[0057] Fig. Figure 9b shows a spring element 920 which, according to a second embodiment, has a variable spring diameter, i.e., at least a first and a second spring diameter D1, D2, and a variable winding spacing, i.e., at least a first and a second winding spacing h1, h2. Preferably, the spring element 920 has three regions I, II, III, wherein region I and region III are preferably identical and region II is preferably arranged between region I and region III. For illustrative purposes, regions I and III are provided with a spring diameter D1 and a winding spacing h1, and region II has a spring diameter D2 and a winding spacing h2, wherein, by way of example, the spring diameter D1 is smaller than the spring diameter D2 and the winding spacing h1 is, by way of example, smaller than the winding spacing h2. It is noted that the Fig. The embodiment of the spring element 920 shown in Figure 9b is merely exemplary and is not to be seen as a limitation of the invention. Thus, the spring element 920, as well as the following spring elements (930 in Figure 9b), can be used in various configurations. Fig. 9c, Fig. 940 in Fig. 9d) may also have two or more than three areas. Furthermore, the spring diameter D1 may be larger than the spring diameter D2 and / or the winding spacing h1 may be larger than the winding spacing h2.

[0058] Fig. Figure 9c shows a spring element 930 which, according to a third embodiment, has a constant spring diameter D and a variable winding spacing, i.e., at least a first and second winding spacing h1, h2. Analogous to Fig. 9b The spring element 930 has three regions I, II, III, wherein region I and region III are preferably identical and region II is arranged between region I and region III. For illustrative purposes, regions I and III are provided with a winding spacing h1 and region II has a winding spacing h2, wherein the winding spacing h1 is preferably smaller than the winding spacing h2. However, the winding spacing h1 can also be larger than the winding spacing h2.

[0059] Fig. Figure 9d shows a spring element 940 which, according to a fourth embodiment, has a constant winding spacing h and a variable spring diameter, i.e., at least a first and second spring diameter D1, D2. Analogously to Fig. 9b and Fig. Figure 9c shows that the spring element 940 has three regions I, II, and III, wherein region I and region III are preferably identical and region II is preferably arranged between region I and region III. For illustrative purposes, regions I and III are provided with a spring diameter D1, and region II has a spring diameter D2, wherein the spring diameter D1 is preferably smaller than the spring diameter D2. However, the spring diameter D1 can also be larger than the spring diameter D2.

[0060] The exemplary spring elements 910 illustrate this. Fig. 9a, Fig. 920 in Fig. 9b, Fig. 930 in Fig. 9c and Fig. 940 in Fig.Figure 9d shows a round spring wire profile. However, it should be noted that the round spring wire profile is merely exemplary and is not to be seen as a limitation of the invention. Thus, the respective spring element can also have an oval or angular, e.g. rectangular, spring wire profile.

Claims

[1] Hand-held power tool (100) with a mechanical rotary impact mechanism (122) for impact driving of an insert tool (140), wherein the rotary impact mechanism (122) has a spring-loaded impact body (225) which is coupled to the rotary drive with an associated drive shaft (120) and is mounted axially displaceable on the drive shaft (120), characterized by , that the impact body (225) is acted upon by at least one spring element (228; 510) which has at least two different spring constants (Fc1, Fc2), wherein the at least one spring element (228) is designed in the manner of a spring system (605; 705) with at least two individual spring elements (610, 620; 720, 730), wherein the individual spring elements (610, 620) have different spring constants (Fc1, Fc2), characterized by, that the at least two individual spring elements (610, 620; 720, 730) are arranged in parallel to each other, wherein, in a starting position of the impact body (225) the at least two individual spring elements (610, 620) are arranged in parallel, a first individual spring element (610) is in contact with the impact body (225) and a second individual spring element (620) is arranged spaced apart from the impact body (225) by a predetermined distance (630). [2] Hand-held power tool according to claim 1, characterized by , that the at least one spring element (228) is designed in the manner of a conical spring (510). [3] Hand-held power tool according to claim -1, characterized by , that the at least two individual spring elements (610, 620) are arranged one inside the other when connected in parallel. [4] Hand-held power tool according to claim -1, characterized by , that the at least two individual spring elements (720, 730) are connected to each other via an intermediate element (710) in series connection. [5] Hand-held power tool according to claim 4, characterized by , that the intermediate element (710) is provided with an adjustment mechanism (810) for setting an initial spring constant. [6] Hand-held power tool according to claim 5, characterized by , that the adjusting mechanism (810) for adjusting the initial spring constants has a spring-loaded locking element (820). [7] Hand-held power tool according to any one of the preceding claims, characterized by , that the at least one spring element (228; 910, 920, 930, 940) and / or the at least two individual spring elements (610, 620; 720, 730) each have a constant or variable spring diameter (D1, D2) and / or a constant or variable winding spacing (h1, h2). [8] Mechanical rotary impact mechanism (122) for a hand-held power tool (100) according to one of the preceding claims for the impact drive of an insert tool (140), wherein the rotary impact mechanism (122) has a spring-loaded impact body (225) which can be coupled to a drive shaft (120) of the hand-held power tool (100) for rotary drive and can be mounted axially displaceable on the drive shaft (120), characterized by , that the impact body (225) is acted upon by at least one spring element (228; 510) which has at least two different spring constants (Fc1, Fc2).

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