MACHINE TOOL WITH A LOCKING DEVICE

Description

State of the art

[0001] The present invention relates to a hand-held power tool with a tool holder comprising a tubular tool holder in which an insert tool can be locked by an associated locking device via at least one locking element, wherein the locking device comprises a pressure sleeve actuated by an associated spring element and a stop sleeve, wherein the tubular tool holder has at least one recess in which the at least one locking element is arranged at least partially in a locking position, and wherein the spring-actuated pressure sleeve acts on the at least one locking element in the locking position against the stop sleeve and into the recess of the tool holder.

[0002] From EP 2 894 009 A1, a hand-held power tool is known which has a locking device for locking an insert tool in a tubular tool holder. The locking device has locking elements which, in a corresponding locking position, are acted upon by a spring-loaded pressure sleeve against a contact surface of a stop sleeve. The locking elements are, by way of example, designed as latches which, in the corresponding locking position, are arranged at least partially in corresponding recesses of the tubular tool holder.

[0003] Furthermore, a hand-held power tool is known from DE 195 21 993 A1, which has a locking device for locking an insert tool in a tubular tool holder. The locking device has locking elements which, in a corresponding locking position, are acted upon by a spring-loaded locking sleeve against a contact surface of a drive spindle. The locking elements have two spherical ends which are connected to each other by means of a web. One spherical end, facing the locking sleeve, is arranged in a pocket of the locking sleeve. Disclosure of the invention

[0004] The invention relates to a hand-held power tool with a tool holder comprising a tubular tool holder in which an insert tool can be locked by an associated locking device via at least one locking element, wherein the locking device comprises a pressure sleeve actuated by an associated spring element and a stop sleeve. The tubular tool holder has at least one recess in which the at least one locking element is arranged at least partially in a locked position, and wherein the spring-actuated pressure sleeve presses the at least one locking element against the stop sleeve and into the recess of the tool holder in the locked position.The stop sleeve has at least one contact surface on its inner circumference which is adapted to an outer contour of the at least one locking element in order to enable surface contact between the at least one contact surface and the at least one locking element in the locking position, wherein the at least one locking element is designed as a locking ball, and wherein the at least one contact surface is at least partially spherical.

[0005] By adapting the contact surface of the stop sleeve to the outer contour of the at least one locking element and creating surface contact between the contact surface and the at least one locking element in the locked position, the resistance of the stop sleeve to wear can be significantly increased. This advantageously extends the service life of the stop sleeve, and thus of the tool holder as a whole, due to the resulting reduction in wear. Furthermore, increasing the resistance of the stop sleeve to wear also allows the tool holder to be used in comparatively powerful hand-held power tools, whose performance may exceed that of conventional hand-held power tools.Furthermore, regardless of the design of the spring-loaded pressure sleeve, at least the stop sleeve can be designed to reduce wear.

[0006] According to one embodiment, the spring-loaded pressure sleeve has at least one receptacle in which the at least one locking element is received, wherein the at least one receptacle is associated with a pressure surface for applying force to the at least one locking element in the locking position, and wherein the pressure surface is adapted to the outer contour of the at least one locking element in order to enable surface contact between the pressure surface and the at least one locking element in the locking position.

[0007] By adapting the pressure surface of the spring-loaded pressure sleeve to the outer contour of the at least one locking element and creating surface contact between the pressure surface and the at least one locking element in the locked position, the resistance of the spring-loaded pressure sleeve to wear can be significantly increased. This, in turn, advantageously extends the service life of the spring-loaded pressure sleeve, and thus of the tool holder as a whole, due to the resulting reduction in wear. Furthermore, increasing the resistance of the spring-loaded pressure sleeve to wear also allows the tool holder to be used in comparatively powerful hand-held power tools, whose performance may exceed that of conventional hand-held power tools.

[0008] Preferably, the printing surface is at least partially spherical.

[0009] This allows for the provision of a safe and reliable locking element that enables a simple and straightforward design of the printing surface.

[0010] Preferably, the at least one receptacle of the spring-loaded pressure sleeve is designed to allow a clearance-enabled receptacle for the at least one locking element.

[0011] Due to the clearance provided by the at least one locking element in the receptacle of the spring-loaded pressure sleeve, the at least one locking element can move freely within specified tolerances. This advantageously reduces the forces required to displace the spring-loaded pressure sleeve.

[0012] According to one embodiment, the spring-loaded pressure sleeve is displaceable against a spring force of the associated spring element in the longitudinal direction of the tubular tool holder in order to move the at least one locking element from the locking position to the unlocking position.

[0013] This advantageously means that only a movement of the spring-loaded pressure sleeve is required to move the at least one locking element from the locked position to the unlocked position. This can advantageously be achieved by moving the spring-loaded pressure sleeve by means of an associated locking sleeve.

[0014] Preferably, a locking sleeve is provided which is displaceable in the longitudinal direction of the tubular tool holder to move the spring-loaded pressure sleeve against the spring force of the associated spring element.

[0015] This allows for a simple and straightforward unlocking process by means of a movement of the locking sleeve.

[0016] Preferably, the locking sleeve has an actuation section which, when the locking sleeve is displaced longitudinally against the spring-loaded pressure sleeve, displaces the spring-loaded pressure sleeve against the spring force of the associated spring element.

[0017] Thus, an unlocking process can be carried out in a simple way by moving the locking sleeve.

[0018] According to one embodiment, the locking sleeve has a groove-shaped grip area.

[0019] The groove-shaped design of the grip area advantageously allows for a comparatively slim design of the locking sleeve, effectively preventing unwanted actuation of the locking sleeve during operation. This also prevents the uncontrolled unlocking of an insert tool locked in the tool holder of the hand-held power tool during operation.

[0020] According to one embodiment, the hand-held power tool is designed in the manner of a drill or chisel hammer, wherein the tubular tool holder has a hammer tube.

[0021] This makes it easy and straightforward to provide a suitable hand-held power tool. Brief description of the drawings

[0022] The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. The drawings show: Fig. 1 a side view of a hand-held power tool with a tool holder according to the invention, Fig. 2 a longitudinal section through the tool holder of Fig. 1 In the locked state, Fig. 3 shows a perspective view of a stop sleeve of the tool holder. Fig. 2 , Fig. 4 a sectional view of the stop sleeve of Fig. 3 , Fig. 5 a perspective view of a pressure sleeve of the tool holder of Fig. 2 , and Fig. 6 a sectional view of the pressure sleeve of Fig. 5 . Description of the exemplary implementations

[0023] In the figures, elements with the same or comparable function are given identical reference symbols and described in detail only once.

[0024] Fig. 1 Figure 1 shows an exemplary hand-held power tool 100 with a housing 110 in which, for illustrative purposes, a drive unit 120 for driving a tool holder 140 is arranged. The tool holder 140 is preferably designed to hold an insert tool 190. Preferably, the tool holder 140 is a 22 mm hex tool holder, but it can also be designed as an SDSmax or SDSplus tool holder, or as any other suitable tool holder.

[0025] Optionally, a gearbox 130 is assigned to the drive unit 120. However, the hand-held power tool 100 can also be configured without the gearbox 130.

[0026] Furthermore, the hand-held power tool 100 preferably includes a percussion mechanism 150 for generating impact impulses in a percussion mode of the hand-held power tool 100. The generation of impact impulses by means of the percussion mechanism 150 is well known to those skilled in the art. A suitable percussion mechanism with which the percussion mechanism 150 can be implemented is also well known to those skilled in the art, so that, for the sake of simplicity and brevity, a detailed description of the percussion mechanism 150 and its functionality is omitted here.

[0027] For illustrative purposes, the housing 110 has a handle 105 on its side 104 facing away from the tool holder 140 and an optional auxiliary handle 115 on its side 102 facing the tool holder 140. Preferably, the housing 110 is provided with a finishing flange 112 on its side 102.

[0028] Furthermore, the hand tool 100 can be operated via mains power, i.e., connected to a power grid via a power cable 199. However, the hand tool 100 can also be operated wirelessly, e.g., via a battery pack.

[0029] Preferably, the hand-held power tool 100 is designed in the manner of a rotary hammer or chisel hammer. Such a hand-held power tool 100 is sufficiently known from the prior art, which is why a detailed description is omitted here for the sake of brevity.

[0030] Fig. 2 shows the tool holder 140 of Fig. 1 , as well as a section of the housing 110 of the hand-held machine tool 100, which is fitted with the end flange 112. Fig. 1 The tool holder 140 has a locking device 200 by means of which the exemplary insert tool 190 can be locked in place. Fig. 1 The tool holder 140 is locked in place. The locking device 200 is shown in an exemplary locked state. The tool holder 140, and thus also the locking device 200, has, for illustrative purposes, a longitudinal extent 203, which defines an axial direction, and a transverse extent 206, which defines a radial direction.

[0031] The tool holder 140 has a tubular tool holder 210 which has at least one recess 216. Preferably, the tool holder 210 has a hammer tube 211 and is preferably formed integrally with it.

[0032] For illustrative purposes, the tool holder 210 forms an internal recess 240 for receiving the insert tool 190. The hammer tube 211 forms an internal recess 212 by way of example, in which preferably at least one part of the impact mechanism 150 is located. Fig. 1 The assigned racket 214 is arranged.

[0033] The tool holder 140 is shown in the upper half of the image, viewed in the direction of arrows 201, as an example before the transfer of an impact impulse from the beater 214 to the insert tool 190. In the lower half of the image, viewed in the direction of arrows 202, the tool holder 140 is shown as an example during impact operation, during the transfer of an impact impulse from the beater 214 to the insert tool 190.

[0034] The insert tool 190 has, for illustrative purposes, a locking section 205 facing the striker 214, by means of which the insert tool 190 is locked in the tool holder 210, and thus in the tool receptacle 140, by the locking device 200. According to the invention, the locking device 200 is associated with at least one locking element 250, which is arranged in the at least one recess 216 of the tool holder 210 for locking the insert tool 190.

[0035] Preferably, two or three locking elements 250 are provided, each locking element engaging in a corresponding recess of the tool holder 210. However, more than three locking elements 250 can also be present. According to the invention, the locking element 250 is designed as a locking ball.

[0036] It should be noted at this point that the in Fig. 2 The illustrated exemplary implementation assumes the use of three locking balls. These are preferably arranged at an angular distance of 120° relative to each other. Therefore, in Fig. 2 In the lower half of the image, seen in the direction of arrows 202, there is also no locking ball present, since the lower half of the image is arranged at an offset of 180° to the upper half of the image, seen in the direction of arrows 201, in which a locking ball of the locking device 200 is shown.

[0037] According to the invention, the locking device 200 comprises a pressure sleeve 230, which is spring-loaded via an associated spring element 280, and a stop sleeve 242. The stop sleeve 242 has at least one contact surface 244 on its inner circumference 249. The at least one contact surface 244 is adapted to an outer contour 255 of the at least one locking element 250 in order to enable surface contact between the at least one contact surface 244 and the at least one locking element 250 in the locked position. Preferably, each locking element is assigned one contact surface.

[0038] The spring-loaded pressure sleeve 230 preferably has an actuation collar 236 against which the associated spring element 280 abuts in order to actuate the spring-loaded pressure sleeve 230 into a locking position as shown. For illustrative purposes, the actuation collar 236 has a bearing edge 234 against which the associated spring element 280 abuts.

[0039] It is pointed out that, in the context of the present invention, the term "sleeve" is to be understood as encompassing any round, preferably elongated, hollow object into which something can be inserted. Accordingly, in the context of the present invention, the term "sleeve" also includes a wide ring, or a plurality of interconnected webs, which, for example, extend along the surface of a cylinder and whose enclosing surface is annular, etc.

[0040] According to the invention, the spring-loaded pressure sleeve 230 presses the at least one locking element 250 in the locked position against the at least one contact surface 244 of the stop sleeve 242. For this purpose, the spring-loaded pressure sleeve 230 preferably has at least one pressure surface 232 for applying force to the at least one locking element 250 in the locked position. Preferably, each locking element is assigned a pressure surface. The pressure surface 232 is preferably arranged facing the locking element 250. Preferably, the spring-loaded pressure sleeve 230 is displaceable against a spring force of the associated spring element 280 in the longitudinal direction 203 of the tool holder 210 in order to move the at least one locking element 250 from the locked position to the unlocked position.

[0041] For illustrative purposes, the spring-loaded pressure sleeve 230 also has at least one receptacle 229, or preferably one receptacle for each locking element. The at least one receptacle 229 is preferably associated with the at least one pressure surface 232 for applying force to the at least one locking element 250 in the locked position. Preferably, the pressure surface 232 is also adapted to the outer contour 255 of the at least one locking element 250 to enable surface contact between the pressure surface 232 and the at least one locking element 250 in the locked position.

[0042] The at least one receptacle 229 is exemplified by being formed in a sleeve-shaped body 231 of the spring-loaded pressure sleeve 230. The sleeve-shaped body 231 is preferably guided axially displaceably on an outer circumference 218 of the tool holder 210.

[0043] The at least one locking element 250 is preferably mounted with clearance in the at least one receptacle 229, i.e., such that the at least one locking element 250 can move freely within specified tolerances in the receptacle 229. The at least one locking element 250 engages, at least partially, the locking section 205 of the insert tool 190 via the recess 216 of the tool holder 210 and thus locks the insert tool in the tool holder 210 or in the tool receptacle 140.

[0044] Furthermore, the locking device 200 preferably has a locking sleeve 220 that is displaceable in the longitudinal direction 203 of the tool holder 210 in order to move the spring-loaded pressure sleeve 230 from its locking position to an unlocking position. This displacement occurs against the spring force of the spring element 280. Alternatively, the locking sleeve 220 and the spring-loaded pressure sleeve 230 can also be formed in one piece, or at least the sleeve-shaped body 231 of the spring-loaded pressure sleeve 230 can be designed as an integral part of the locking sleeve 220.

[0045] Preferably, the locking sleeve 220 is provided with a groove-shaped grip area 224. This groove-shaped grip area 224 forms, for illustrative purposes, an annular grip recess 227. Viewed in the longitudinal direction 203, the annular grip recess 227 preferably has a circular cross-section, but can alternatively have any other cross-section, e.g., a polygonal one.

[0046] The locking sleeve 220 can be made of a first material, and the spring-loaded pressure sleeve 230 can be made of a second material. The first material is preferably a plastic, in particular a dimensionally stable plastic, e.g., rigid plastic. Furthermore, the plastic can be a fiber-reinforced plastic, in particular a fiber-reinforced and / or carbon fiber-reinforced plastic, e.g., polyamide with glass fiber. The second material is preferably a metallic material, preferably steel. In particular, the second material is preferably a hardenable material, e.g., metal or sintered material.

[0047] For illustrative purposes, the locking sleeve 220 has a first axial end 291 facing the end flange 112 and an opposing second axial end 292. In the region of the first axial end 291, the locking sleeve 220 preferably has a guide section 222. In the region of the second axial end 292, the locking sleeve 220 preferably has an engagement section 226. Between the engagement section 226 and the guide section 222, the groove-shaped grip area 224 is preferably arranged in the longitudinal direction 203 of the tool holder 210.

[0048] The guide section 222 preferably forms an internal recess 221 in which the actuation collar 236 of the spring-loaded pressure sleeve 230 and the spring element 280 are at least partially arranged. The guide section 222 preferably has an end wall 223 facing the groove-shaped grip area 224, which forms an actuation section against which the spring element 280, for illustrative purposes, spring-loads the actuation collar 236 in the locking position of the at least one locking element 250. By way of example, a bearing edge 235 of the actuation collar 236 is spring-loaded against the end wall 223, or the actuation section 223.

[0049] For illustrative purposes, the guide section 222 serves to guide the locking sleeve 220 on a guide sleeve 281. This is preferably attached to the end flange 112 of the housing 110.

[0050] The engagement section 226 preferably forms an internal recess 225, in which, in the locked state of the locking device 200, as in Fig. 2 As shown, preferably a damping element 260 is arranged. The damping element 260 is, for illustrative purposes, ring-shaped and arranged on the outer circumference 218 of the tool holder 210. Furthermore, the damping element 260 preferably abuts the stop sleeve 242 in the longitudinal direction 203 of the tool holder 210, against which a first inner collar 228 of the locking sleeve 220 also abuts. For illustrative purposes, the first inner collar 228 abuts an outer collar 247 of the stop sleeve 242. A second inner collar 270 of the locking sleeve 220, which is formed, for example, by the actuation section 223 of the locking sleeve 220, also abuts the stop sleeve 242.

[0051] For illustrative purposes, an outer collar 275 is associated with the engagement section 226. The outer collar 275 preferably forms a transition from the engagement section 226 to the groove-shaped grip area 224.

[0052] Preferably, the engagement section 226 engages in a protective cap 245 when the locking device 200 is in the locked state. The protective cap 245 is preferably arranged at a free end 209 of the tool holder 210.

[0053] For illustrative purposes, the protective cap 245 is provided with a receiving section 248. The damping element 260 is received in the receiving section 248, as is at least part of the stop sleeve 242. Preferably, at least the engagement section 226 of the locking sleeve 220 engages in the receiving section 248 when the locking device 200 is locked.

[0054] To lock the insert tool 190 in the tool holder 140, the insert tool 190 is inserted into the tool holder 210 in the direction of the striker 214. In doing so, the insert tool 190 presses against the at least one locking element 250 arranged in the recess 216 and displaces it against the spring-loaded pressure sleeve 230 and then with it, such that the at least one locking element 250 is pushed out of the recess 216 towards the end flange 112 to such an extent that an end of the insert tool 190 facing the striker 214 is pushed past the at least one locking element 250.Subsequently, the spring-loaded pressure sleeve 230, through the spring force of the spring element 280, pushes the at least one locking element 250 back into the recess 216, where the at least one locking element 250 engages at least partially in the locking section 205 of the insert tool 190 and thus locks the insert tool 190 in the tool holder 210.

[0055] In the locked state of the locking device 200, the spring-loaded pressure sleeve 230, through the spring force of the spring element 280, presses the at least one locking element 250 against the at least one contact surface 244 of the stop sleeve 242 and into the recess 216 of the tool holder 210 to lock the insert tool 190. In this process, the spring-loaded pressure sleeve 230 also presses the locking sleeve 220 against the stop sleeve 242, so that the outer collar 275 of the locking sleeve 220 preferably rests flush against the receiving section 248 of the protective cap 245.

[0056] To unlock the locking device 200, the locking sleeve 220 is preferably moved in the longitudinal direction 203 of the tool holder 140 against the spring-loaded pressure sleeve 230, and thus with it against the spring force of the spring element 280 in the direction of the guide sleeve 281. In doing so, the spring-loaded pressure sleeve 230 takes the at least one locking element 250 with it, so that it is pushed out of the recess 216 of the tool holder 210 at least far enough to release the locking section 205 of the insert tool 190 and thus the insert tool 190.

[0057] Fig. 3 The stop sleeve 242 of the locking device 200 of the tool holder 140 is shown. Fig. 2 The stop sleeve 242 is shown with an outer collar 247 and three contact surfaces 244 on its inner circumference 249. The three contact surfaces 244 are marked separately with reference numerals 310, 320, and 330 for clarity.

[0058] As in Fig. 2 As described, three locking elements are preferably, but not necessarily, used, to which the three contact surfaces 310, 320, 330 are assigned. These are each adapted to the outer contour of the locking elements to enable surface contact between each of the contact surfaces 310, 320, 330 and each assigned locking element in the locked position.

[0059] The three locking elements as in Fig. 2 The described components are designed as locking balls. Accordingly, the three contact surfaces 310, 320, 330 are at least partially spherical.

[0060] Fig. 4 shows the stop sleeve 242 of Fig. 3 with the facility areas 244, of which only facility area 310 and, in sections, facility area 320 are visible here. Fig. 4 illustrates the at least partially spherical design of the plant areas 244.

[0061] Fig. 5 The spring-loaded pressure sleeve 230 of the locking device 200 of the tool holder 140 is shown. Fig. 2 The spring-loaded pressure sleeve 230 is illustrated with the actuation collar 236, as well as three receptacles 229, each of which has an associated pressure surface 232. Accordingly, there are three pressure surfaces 232, of which in Fig. 5 However, only two are visible and are marked separately with reference numbers 510 and 520 for clarity.

[0062] As in Fig. 2 As described, preferably, but not necessarily, three locking elements are used, to which the three pressure surfaces 232 are assigned. These are preferably each adapted to the outer contour of the locking elements in order to enable surface contact between each of the pressure surfaces 232 and each assigned locking element in the locked position.

[0063] The three locking elements as in Fig. 2 The described components are designed as locking balls. Accordingly, the three pressure surfaces 232 are at least partially spherical.

[0064] Fig. 6 shows the spring-loaded pressure sleeve 230 of Fig. 5 with the printing surfaces 232, of which only printing surface 520 and partially printing surface 510 are visible here. Fig. 6 illustrates the at least partially spherical design of the printing surfaces 232.

Claims

1. Hand-held machine tool (100) with a tool receptacle (140) having a tubular tool holder (210) in which an insert tool (190) is able to be locked by an assigned locking device (200) by way of at least one locking element (250), wherein the locking device (200) has a thrust sleeve (230), which is spring-loaded by way of an assigned spring element (280), and a detent sleeve (242), wherein the tubular tool holder (210) has at least one clearance (216) in which the at least one locking element (250) is at least in portions disposed in a locked position, and wherein the spring-loaded thrust sleeve (230) impinges the at least one locking element (250) in the locked position against the detent sleeve (242) and into the clearance (216) of the tool holder (210), characterized in that the detent sleeve (242) has on its internal circumference (249) at least one detent face (244) which is adapted to an external contour (255) of the at least one locking element (250) so as to enable surface contact between the at least one detent face (244) and the at least one locking element (250) in the locked position, wherein the at least one locking element (250) is designed as a locking sphere, and the at least one detent face (244) is at least in portions designed to be spherical.

2. Hand-held machine tool according to Claim 1, characterized in that the spring-loaded thrust sleeve (230) has at least one receptacle (229) in which the at least one locking element (250) is received, wherein the at least one receptacle (229) is assigned a thrust face (232) for applying force to the at least one locking element (250) in the locked position, and wherein the thrust face (232) is adapted to the external contour (255) of the at least one locking element (250) so as to allow surface contact between the thrust face (232) and the at least one locking element (250) in the locked position.

3. Hand-held machine tool according to Claim 2, characterized in that the thrust face (232) is at least in portions designed to be spherical.

4. Hand-held machine tool according to Claim 3, characterized in that the at least one receptacle (229) of the spring-loaded thrust sleeve (230) is designed to allow the at least one locking element (250) to be received with play.

5. Hand-held machine tool according to one of the preceding claims, characterized in that the spring-loaded thrust sleeve (230) is displaceable in the longitudinal direction (203) of the tubular tool holder (210), counter to a spring force of the assigned spring element (280), so as to displace the at least one locking element (250) from the locked position to an unlocked position.

6. Hand-held machine tool according to Claim 5, characterized in that provided is a locking sleeve (220) which for displacing the spring-loaded thrust sleeve (230) is displaceable in the longitudinal direction (203) of the tubular tool holder (210), counter to the spring force of the assigned spring element (280).

7. Hand-held machine tool according to Claim 6, characterized in that the locking sleeve (220) has an impingement portion (223) which, when displacing the locking sleeve (220) in the longitudinal direction (203), counter to the spring-loaded thrust sleeve (230), displaces the spring-loaded thrust sleeve (230) counter to the spring force of the assigned spring element (280).

8. Hand-held machine tool according to Claim 6 or 7, characterized in that the locking sleeve (220) has a groove-shaped gripping region (224).

9. Hand-held machine tool according to one of the preceding claims, which is designed in the manner of a hammer drill or chipping hammer, wherein the tubular tool holder (210) has a hammer tube (211).