Power tools equipped with a coupling mechanism
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ATLAS COPCO IND TECHNIQUE AB INTELLECTUAL PROPERTY DEPARTMENT
- Filing Date
- 2022-11-01
- Publication Date
- 2026-07-31
Smart Images
Figure 0007898522000001 
Figure 0007898522000002 
Figure 0007898522000003
Abstract
Description
Technical Field
[0001] The present invention relates to the field of power tools with replaceable removable tool heads. Such removable tool heads can be exchanged with another tool head by removing the current tool head and inserting a new tool head according to the work to be performed. Usually, the removable tool head is arranged at the front end of the power tool.
Background Art
[0002] When various removable tool heads for performing different types of work are provided for a power tool, usually, the coupling mechanism includes a sleeve arranged at the front end of the power tool, and this sleeve can be manually moved backward away from the front end of the power tool or forward toward the front end so that the removable tool head can be released for exchange with another tool head. Usually, this exchange procedure is difficult and cumbersome for the operator. Even when the sleeve is pulled back, no tactile or acoustic feedback is given to the operator regarding whether the removable tool head has been correctly released or whether the new tool head has been correctly engaged. Further, usually, for this engagement, the operator needs to push the sleeve back toward the front end of the power tool to lock the removable tool head to the coupling mechanism and the power tool respectively. Alternatively, the operator needs to pull the sleeve back again by holding the sleeve with one hand during the insertion of another tool head or throughout the entire exchange procedure. During the removal stage of the exchange procedure, both hands of the operator are often required, with one hand holding the sleeve as described to remove the removable tool head currently engaged with the power tool via the coupling mechanism and the other hand holding the tool head. The situation is not much better during the insertion stage of another tool head either, as it is necessary to control and pull the sleeve with one hand while inserting the other new tool head with the other hand.
[0003] In addition to the above, these coupling mechanisms are typically quite complex in structure, requiring multiple elements, recesses, balls, and springs to function correctly, making them cumbersome to assemble, prone to reliability issues, heavy, and expensive. For example, an example of such a coupling mechanism is shown in U.S. Patent No. 10,569,343B2, which discloses an attachment retainer or drive tool for receiving a socket or bit, with rotational locking achieved using splines and grooves and axial locking achieved via balls. As can be seen from U.S. Patent No. 10,569,343B2, the coupling mechanism is designed to be releasably locked by rotating a sleeve or the like around a longitudinal axis defined by the socket.
[0004] European Patent Application Publication No. 3,228,408A1 describes another example of a coupling mechanism for locking a bit into a bit adapter, the mechanism comprising multiple planes and balls. The rotational lock of the coupling mechanism shown in European Patent Application Publication No. 3,228,408A1 is achieved via a form-fit coupling between a hexagonal or planar bit end and a hexagonal opening in the bit adapter having two grooves that receive either the hexagonal or planar bit end. The mechanism is designed to lock the bit within the bit adapter. For removal, the outer sleeve of European Patent Application Publication No. 3,228,408A1 can be advanced toward the bit. This unlocks the bit, allowing the first ball to move freely outward at this point, so that the bit can be manually removed. The design of European Patent Application Publication No. 3,228,408A1 is considerably more complex due to the use of multiple planes and balls, and therefore at least two balls, as well as a form-fit solution for rotational and axial locking, and for locking the outer sleeve in the open position, which makes it prone to the aforementioned drawbacks. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] U.S. Patent No. 10,569,343 [Patent Document 2] European Patent Application Publication No. 3,228,408 [Overview of the Initiative] [Problems that the invention aims to solve]
[0006] From the above points, there is a need to provide a coupling mechanism and power tools for power tools that are easy for operators to handle and effective in manufacturing and assembly.
[0007] The objective of this invention is to provide a safe, easy-to-handle, efficient, and reliable power tool. [Means for solving the problem]
[0008] In light of the above-mentioned problems, the inventors have discovered that the coupling mechanism for a removable tool head in a power tool can be simplified to require only one ball, or one plane of a ball, for axial and rotational locking of the tool head. The inventors have also discovered that the coupling mechanism can be simplified so that the operator can change the tool head with one hand. At the same time, this coupling mechanism can provide clear tactile and / or acoustic feedback regarding the locking and unlocking of the removable tool head in the coupling mechanism, so that the operator can clearly identify whether the tool head is properly engaged with or disengaged from the power tool.
[0009] This specification discloses a power tool comprising a motor, a gearbox, a drive shaft defining a longitudinal axis connected to or via the gearbox to the motor, and a front end having at least one through hole, the axis of the through hole passing through the longitudinal axis perpendicular to the longitudinal axis, and the front end defining a cavity including a tool-side end and an open end. The power tool further comprises a coupling mechanism for releasably connecting a removable tool head to the drive shaft, the coupling mechanism including an outer sleeve disposed at least partially surrounding the cavity, the coupling mechanism further including a first biasing element and at least one ball at least partially disposed within at least one through hole, the at least one ball further disposed inside the outer sleeve. The outer sleeve includes an inclined inner surface and an inner projection adjacent to the inclined inner surface, the first biasing element being disposed at the front end and in contact with the outer sleeve and the front end. The coupling mechanism is arranged to move between an open position in which the power tool can receive a removable tool head and a closed position in which the removable tool head is connected to the power tool and locked inside it, so that in the open position at least one ball can be displaced outward away from the longitudinal axis, and in the closed position outward displacement of at least one ball is prevented by an inner projection of the outer sleeve. The coupling mechanism further includes an inner sleeve at least partially disposed within the cavity and a second biasing element that abuts the tool-side end of the cavity and the inner sleeve, so that in the open position the inner sleeve prevents the inner projection from abutting at least one ball.
[0010] In the above embodiment, two sleeves, two biasing elements (first and second), and at least one ball are used, which work together to place the coupling mechanism in either an open or closed position, ready to receive a removable tool head, and when the inner sleeve is manually shifted during the insertion of another tool head, it is placed in the closed position, and at least one ball engages at least partially smoothly with a recess on the removable tool head and locks therein via an inner projection of the outer sleeve, which is held in place by the first biasing element.
[0011] This design enables an efficient structure for the coupling mechanism, making it easy for the operator to use and allowing it to be managed essentially with one hand. In addition, the first and second biasing elements, as well as at least one ball, provide clear acoustic and tactile feedback when engaging, locking, and releasing the removable tool head.
[0012] In one embodiment, when the power tool is in the closed position, the inner sleeve is biased toward the tool-side end by the removable tool head, thereby enabling inward displacement of at least one ball toward the longitudinal axis (a), so that at least one ball can engage with at least one recess of the removable tool head, and the inner projection abuts against at least one ball, thereby locking the removable tool head within the power tool via at least one ball and at least one recess.
[0013] The operator can hear and feel a click when at least one ball engages with the recess, and can detect this lock by the outer sleeve moving to the locked position.
[0014] In another embodiment, the inclined surface is configured to guide the inward displacement toward the longitudinal axis (a) of at least one ball during the axial displacement of the outer sleeve by the first biasing element, and as the coupling mechanism moves from an open position to a closed position by pushing the removable tool head and inner sleeve toward the tool-side end of the cavity.
[0015] The inclined surface helps to provide a smooth transition between the open and closed positions by guiding at least one ball from the inclined surface to the inner projection and vice versa when the outer sleeve is displaced.
[0016] In the open position, at least one ball is in contact with the inclined surface.
[0017] In another embodiment, the through-hole is a conical through-hole whose diameter decreases toward the longitudinal axis determined by the drive shaft, so that at least one ball can be positioned within the through-hole and partially extend outward into the cavity from the conical through-hole.
[0018] The minimum diameter of the conical through-hole is not greater than the diameter of at least one ball. And when the inner projection pushes at least one ball into the conical through-hole in the closed position, at least one ball can extend into the cavity and engage with the recess.
[0019] In another embodiment, the first biasing element includes a first passage and the second biasing element includes a second passage, the first passage being positioned to at least partially enclose the cavity and the second passage being designed to receive the drive shaft or connector of a removable tool head.
[0020] In further embodiments, the coupling mechanism may include at least two balls, preferably four balls, more preferably six balls, and even more preferably eight to fourteen balls, with the number of through holes at the front end and the number of recesses in the removable tool head corresponding to the number of balls in the coupling mechanism.
[0021] The greater the number of balls provided in the coupling mechanism and the corresponding through holes, the more balls can be engaged with the many recesses by simply rotating the removable tool head slightly when inserting the removable tool head into the cavity at the front end. Thus, it becomes easier to rotate and lock the removable tool head to the coupling mechanism and the power tool. However, due to the bushing of the tool head and the stability of the front end of the power tool, there are limits to the number of balls and recesses that can be used, respectively.
[0022] In some embodiments, 10 or 12 balls and corresponding through holes and recesses can be provided, and basically, any number from 1 to 30 or more balls and the corresponding number of through holes and recesses can be provided.
[0023] In one embodiment, the inner sleeve includes a shoulder designed to abut against the tool-side end of the removable tool head in the closed position. This shoulder is designed to push the removable tool head out of the cavity when manually displacing the outer sleeve against the biasing force of the first biasing element and when the coupling mechanism moves to the open position.
[0024] This makes it clearly visible to the operator that the removable tool head is disengaged from the power tool and can be removed, or that the removable tool head is not properly engaged and needs to be pushed further or deeper into the cavity.
[0025] In one embodiment, the cavity has a generally cylindrical shape and is arranged parallel to the longitudinal axis (a) such that the center line (a) of the cylindrical shape coincides with the longitudinal axis (a) defined by the drive shaft.
[0026] This aids in the proper functioning of the inner sleeve and the second biasing element, and the outer sleeve and the first biasing element.
[0027] In further embodiments, the inner sleeve and the outer sleeve are configured to move parallel to and concentric with the longitudinal axis (a), respectively, when pushed or pulled manually or by the second biasing element and the first biasing element.
[0028] This promotes the proper functioning of the coupling mechanism and reduces friction, thereby improving the operation of the coupling mechanism.
[0029] In all of the embodiments described above, the outer sleeve can be slid toward or away from the front end of the power tool in order to release the removable tool head and move the coupling mechanism from the closed or locked position to the open position.
[0030] In yet another embodiment, the inner sleeve includes at least one protruding element projecting toward the open end of the cavity, the protruding element being designed to abut against the outer sleeve in at least the open position, and the biasing force of the first biasing element is smaller than the biasing force of the second biasing element, so that the inner sleeve can prevent the outer sleeve from being displaced toward the closed position via the at least one protruding element when the removable tool head is not inserted into the power tool.
[0031] Accordingly, the inner sleeve prevents the outer sleeve from moving to the closed position, in which case the inner projection engages with at least one ball, pushing the ball into the through-hole, thereby preventing the removable tool head from being fully inserted into the cavity and locked inside the power tool.
[0032] In a further embodiment, the inner sleeve is designed to overcome the biasing force of the second biasing element by displacing toward the tool-side end of the cavity when the removable tool head is inserted toward the tool-side end and manually pushed in, thereby allowing the outer sleeve, propelled by the biasing force of the first biasing element, to slide into a closed position, guiding the inclined surface first and then the inner projection to contact at least one ball, which is pushed deep into the through hole and partially extends into the cavity to engage with the recess of the removable tool head.
[0033] In embodiments where the inner sleeve prevents the outer sleeve from moving in the open position, the outer sleeve can be slid away from its front end in order to remove the removable tool head and thus move the coupling mechanism from the closed position to the open position.
[0034] When the inner sleeve is manually displaced, the outer sleeve and the first biasing element become engaged, creating pressure on at least one ball by pushing it through the inclined surface, causing it to move toward the longitudinal axis. As a result, the removable tool head locks into the cavity as soon as the recess aligns with at least one ball, causing the inclined surface to slide over the ball, and ultimately the inner projection to push at least one ball into the through hole and recess.
[0035] In another embodiment, the inner sleeve includes an outer surface which is positioned to contact at least one ball, thereby preventing at least one ball from extending into the cavity in the open position.
[0036] In the above embodiment, the outer surface of the inner sleeve prevents at least one ball from being fully pushed into the through hole via the inclined surface. When the inner sleeve is displaced during insertion of the removable tool head and overcomes the biasing force of the second biasing element, the outer surface immediately disengages from the path of at least one ball, and as a result the recess aligns with the through hole and the ball, respectively, the inclined surface of the outer sleeve can fully push at least one ball into the through hole and engage with the recess of the removable tool head.
[0037] In yet another embodiment, the inner sleeve, and therefore the outer surface, overcomes the biasing force of the second biasing element by displacing toward the tool-side end of the cavity and ceasing to contact at least one ball when the removable tool head is inserted toward the tool-side end of the cavity and manually pushed, thereby allowing the outer sleeve, propelled by the biasing force of the first biasing element, to slide, moving the inclined surface to contact at least one ball, and then the inner projection to contact at least one ball, so that at least one ball can engage with the recess of the removable tool head, causing the coupling mechanism to move to the closed position.
[0038] In another embodiment, the outer sleeve further includes another inclined surface symmetrically adjacent to the inner projection, and the neutral point of the first biasing element is selected such that the inner projection contacts at least one ball when the first biasing element is at the neutral point corresponding to the closed position of the coupling mechanism.
[0039] This allows the operator to move the outer sleeve away from or toward the front end of the power tool to release the removable tool head, and to move the coupling mechanism from the closed position to the open position.
[0040] In another solution, the inner projection extends from the inside of the outer sleeve toward the longitudinal axis (a) and includes a flat top portion, which is configured to contact at least one ball when the coupling mechanism is in the closed position.
[0041] The flat top surface enhances the robustness of the coupling mechanism and can compensate for manufacturing tolerances.
[0042] The present invention and many embodiments have been described above. It will be apparent to those skilled in the art that the above embodiments can be combined in many ways, and that the features of all embodiments can be used in other embodiments. Such embodiments are also included in this disclosure.
[0043] The present invention will be described in further detail below for illustrative purposes, with reference to the accompanying drawings, using (one or more) embodiments. [Brief explanation of the drawing]
[0044] [Figure 1] For example, this is a schematic diagram of a power tool having a removable angled tool head intended for tightening. [Figure 2a] Figure 1 is a schematic cross-sectional view of the power tool, showing a removable angled tool head engaged and locked to the power tool, with the coupling mechanism in the closed position. [Figure 2b] This is a schematic enlarged cross-sectional view of Figure 2a, showing the detailed parts of the coupling mechanism. [Figure 3] Figure 1 is a schematic cross-sectional view of the power tool with the removable angled tool head disengaged and the coupling mechanism in the open position. [Figure 4] This is a schematic cross-sectional view of another embodiment of the present invention, in which a removable angled tool head is disengaged from the power tool and the coupling mechanism is in the open position. [Figure 5] This is a schematic cross-sectional view of another embodiment of the present invention, in which a removable angled tool head engages with a power tool and the coupling mechanism is in the closed position. [Figure 6]This is a schematic diagram of yet another embodiment of the present invention, showing a form of power tool as a screwdriver or drill machine having a removable tool head. [Figure 7] This is a schematic cross-sectional view showing the detachable tool head engaged with the power tool and the coupling mechanism in the closed position. [Figure 8] Figure 6 is a schematic cross-sectional view of the power tool with the removable tool head disengaged and the coupling mechanism in the open position. [Modes for carrying out the invention]
[0045] Figure 1 shows a power tool 1 for tightening screws or bolts, which includes a front end 2 and a removable angled tool head 8. In the embodiment shown in Figure 1, the removable angled tool head 8 is locked and engaged with the power tool 1. Figure 2a is a cross-sectional view of the front portion of the power tool 1 according to Figure 1, i.e., with the removable tool head 8 engaged with the power tool 1 and the coupling mechanism 10 in the closed position. Referring again to Figure 1, the power tool 1 further includes an outer sleeve 16 for disengaging the removable angled tool head 8 to replace it with another tool head, which is disengaged by pushing the outer sleeve 16 forward toward the removable angled tool head 8 from the power tool body 3 so that the removable angled tool head 8 can be slid outward away from the front portion of the power tool 1. Figure 3 is a cross-sectional view of the front portion of the power tool 1 with the removable tool head 8 disengaged and the coupling mechanism 10 in the open position.
[0046] Figure 2a shows a cross-sectional view taken along the plane II-II shown in Figure 1 and along the longitudinal axis a defined by the drive shaft or gear train or gearbox 6. The power tool 1 includes a front end 2, a motor 4, a drive shaft 6 connected to the motor 4, a removable tool head 8, and a coupling mechanism 10.
[0047] The front end 2 includes a cavity 12 having a tool-side end 28, a free end 30, and at least one through-hole 32 for receiving at least one ball 24 of the coupling mechanism 10. The front end 2 is sleeve-shaped, and at least one through-hole 32 is designed to face the longitudinal axis a defined by the drive shaft 6.
[0048] The coupling mechanism 10 includes an outer sleeve 16, a first biasing element 18, an inner sleeve 20, a second biasing element 22, and at least one ball 24. The outer sleeve 16 is positioned along the circumference of the front end 2 and can be manually biased against the resistance of the first biasing element 18 acting toward the body of the power tool 1. The first biasing element 18 contacts the free end 30 of the cavity 12 or at least a stop 35 near it and the inner shoulder 34 of the outer sleeve 16 so that it can push the outer sleeve 16 in the opposite direction, which is a 180-degree rotation of the direction of arrow b shown in Figure 2.
[0049] When the outer sleeve 16 moves in the direction indicated by arrow b in Figure 2b, and therefore toward the free end 30 of the cavity 12 of the front end 2, or toward the removable tool head 8. This will be described in more detail below with reference to Figure 2b.
[0050] Figure 2b shows detailed parts of the outer sleeve 16 and the inner sleeve 20. The outer sleeve 16 includes an inner surface 36, an inclined inner surface 38 adjacent to the inner surface 36, and an inner projection 40 adjacent to the inclined inner surface 38 and projecting from the outer sleeve 16 toward the inside of the cavity 12 and / or toward the longitudinal axis a (see Figure 2a), having a flat portion 58. In the closed position of the coupling mechanism 10, the inner projection 40 abuts against at least one ball 24, pushing the ball 24 into the through hole 32 of the front end 2. This causes at least one ball to partially extend into the cavity 12 and engage with the recess 14 of the removable tool 8. The through hole 32 may have a conical design that decreases in diameter toward the cavity 12 so that at least one ball 24 can easily partially extend when it is fully fitted into the through hole 32.
[0051] The inner projection 40 having an inner surface 36, an inclined inner surface 38, and a flat portion 58 can be arranged circumferentially around the inside of the outer sleeve 16. Alternatively, the inner projection 40 having an inner surface 36, an inclined inner surface 38, and a flat portion 58 can be positioned inside the outer sleeve 16 to engage with at least one or more balls 24, and so the number of inner projections 40 having an inner surface 36, an inclined inner surface 38, and a flat portion 58 can be appropriately adapted if they are not arranged continuously circumferentially. Preferably, the inner projection 40 having an inner surface 36, an inclined inner surface 38, and a flat portion 58 is arranged continuously circumferentially along the inside of the outer sleeve 16.
[0052] Figure 2b also shows an inner sleeve 20, which includes a shoulder 50 positioned at the front end of the inner sleeve 20 facing the free end 30 of the cavity 12. The inner sleeve 20 and the second biasing element 22 further include a recess 52 or central passage for passing the drive shaft 6 of the power tool 1 or the shaft of the removable tool head 8. The inner sleeve further includes an outer surface 54 adjacent to the shoulder 50 that is fitted tightly within the cavity 12 and thus slides smoothly along the inner surface of the cavity 12. Thus, in the region where the inner sleeve 20 moves back and forth, the inner diameter of the cavity 12 corresponds at least somewhat to the outer diameter of the inner sleeve 20, while at the free end 28, the inner sleeve 20 is held in place and cannot exit the cavity 12 because the diameter of the end is smaller than the diameter of the inner sleeve 20.
[0053] As can be seen in Figure 2B, the outer sleeve 16 is manually slid or moved against the biasing force of the first biasing element 18 toward the removable tool head 8 or the free end 30 of the cavity 12. This causes the inner projection 40 and the flat top 58 to disengage from contact with at least one ball 24, and thus the inclined surface 38 to contact with at least one ball 24, causing at least one ball 24 to begin moving away from the recess 14 of the removable tool head 8. When the outer surface of at least one ball 24 is coplanar with the inner surface of the cavity 12, the inner sleeve 20 pushes the removable tool head 8 out of the cavity 12 via the shoulder 50 driven by the biasing force of the second biasing element 22, and the outer surface 54 of the inner sleeve 20 slides over the through hole 32, preventing at least one ball 24 from fully or tightly engaging with the through hole 32 when the removable tool head 8 is removed from the cavity 12. During the described movement, the inclined inner surface 38 slides over at least one ball 24 and contacts at least one ball 24, bringing the coupling mechanism 10 into the open position. Alternatively, the coupling mechanism 10 could be designed so that instead of the inclined inner surface 38 contacting at least one ball 24, the inner surface 36 contacts at least one ball 24. This open position is shown in Figure 3 and will be described below.
[0054] Figure 3 shows the coupling mechanism 10 in the open position, where the outer surface 54 of the inner sleeve 20 essentially closes the through hole 32 (see Figure 2b), preventing at least one ball 24 from entering the recess 14 of the removable tool head 8, while simultaneously holding the power tool 1 open so that another removable tool head can be easily slid into the power tool 1 without the operator having to pull or push the outer sleeve 16. The operator only needs to push the other removable tool head against the biasing force of the second biasing element 22 so that the outer surface 54 moves away from the through hole 32 and at least one ball 24 slides and engages with the recess of the other removable tool head as described above. In the open position as shown in Figure 3, the first biasing element 18 is in the compressed position or compressed state, applying pre-tension to the outer sleeve 16 toward the power tool 1, but this movement is prevented by at least one ball 24 and the outer surface 54 of the inner sleeve. Furthermore, Figure 3 also clearly shows how the inner sleeve 20 is designed to push the removable tool head 8 out of the cavity 12 via the shoulder portion 50 and the second biasing element 22.
[0055] As shown in the figures, the first and second biasing elements 18, 22 may be hydraulic cylinders, elastomers or other forms of rubber cushions, or elastic elements and / or springs. This configuration is possible and shown in all embodiments herein.
[0056] The coupling mechanism 10, as shown in Figures 1 to 3, can be released by manually sliding the outer sleeve 16 in the direction of arrow b, and therefore toward the removable tool head 8, when the tool head 8 is engaged with the power tool 1. However, it is also possible to design the coupling mechanism 110 so that the outer sleeve 116 is slid toward the power tool 1 to release the removable tool head 8. This will be explained below with reference to Figure 4.
[0057] Figure 4 shows a modified coupling mechanism 110, in which the outer sleeve 116 also includes an inner surface 136, an inclined inner surface 138 adjacent to the inner surface 136, and an inner projection 140 having a flat top adjacent to the inclined inner surface 138 (see Figure 2b). However, in this example, the inner surface 136, the inclined inner surface 138, and the inner projection 140 are arranged in a different order than in Figures 2a, 2b, and 3, where the inner surface 36 is positioned close to the tool-side end 28 of the cavity 12, followed by the inclined inner surface 38, and finally the inner projection 40 is positioned closest to the free end 30 of the cavity 12. In the embodiment shown in Figure 4, the inner surface 136 is positioned closest to the free end 130 of the cavity 112, and the inclined inner surface 140 is positioned midway between the inner surface 136 and the inner projection 140. The inner projection 140, having a flat top, is positioned close to the tool-side end 128 of the cavity 112. That is, in the embodiment of Figure 4, the outer sleeve 116 can be manually slid toward the power tool 1 or the tool-side end 128 of the cavity 112, as indicated by arrow b', in order to release the removable tool head 8. The inner sleeve 120 and the first biasing element 122 are designed similarly to the inner sleeve and first biasing element shown in Figures 1 to 3. The first biasing element 118 abuts against the shoulder 160 of the power tool 1, which is positioned close to the outer sleeve 116 and the tool-side end 128 of the cavity 112. In other respects, the coupling mechanism 110 functions similarly to those described with reference to Figures 1 to 3.
[0058] In relation to the embodiment shown in Figures 1 to 3 and 4, in which the outer sleeves 16 and 116 can be slid forward or backward to release the removable tool head 8, it is also possible to provide an outer sleeve 216 that can be slid forward or backward to release the removable tool head 8 and thus move the coupling mechanism 210 to the open position. Such an embodiment is schematically shown in Figure 5.
[0059] The outer sleeve 216 shown in Figure 5 includes two inclined inner surfaces 238 and two inner surfaces 236, which may or may not be arranged to surround the inside of the outer sleeve 216 in a circumferential direction. The two inclined inner surfaces 238 are arranged symmetrically around the inner projection 240, with the two inner surfaces 236 positioned outside each inclined inner surface 238. The second biasing element 218 is positioned between a pair of washers or annular elements 217 that abut the shoulders on the outer sleeve 216 at the tool-side end of the cavity 212, and another washer 219 fixedly connected to the front end 202 of the power tool 1. The washer 219 may consist of two parts, or be two washers 219, such that the inner portion is fixedly engaged or connected to the front end 202 of the power tool outside the cavity 212, and the outer portion of the washer 219 is fixedly connected to the outer sleeve 216. This design allows for compression of the first biasing element 218 when the outer sleeve 216 is moved toward or away from the tool-side end 228 or the front end of the cavity 212, or when it is moved toward or away from the removable tool head 8, in order to release the tool head 8 when the tool is engaged and locked with the power tool 1. In Figure 5, this release movement is indicated by the bidirectional arrow b''. Here again, the design of the inner sleeve 220 is the same as or similar to that described above with reference to Figures 1 to 4, and therefore the engagement and disengagement of at least one ball 224 in the recess and through hole when manually sliding the outer sleeve 216 when the coupling mechanism 210 is in the closed position, and when inserting another tool head when the coupling mechanism 210 is in the open position.
[0060] Next, another embodiment of the present invention will be described with reference to Figures 6 to 8, which show a power tool 301 in the form of a handheld drill, including a removable tool head 308, a drive shaft 306, and an outer sleeve 316. The removable tool head 308 in Figure 2 includes a total of about 10 to 14 recesses 314 and therefore a similar number of balls 324, although it is also possible to use fewer balls than recesses 314. Other embodiments shown herein may include a similar number of balls 324 and corresponding recesses 314, or fewer balls 324.
[0061] In Figure 6, the cavity 312 at the front end 302 of the power tool 301 is clearly visible, and this cavity 312 is configured to receive the removable power tool 308. The coupling mechanism 310 (see Figure 7) is in an open position that can receive the removable tool head 8. In the embodiments shown in Figures 1 to 5, it was shown that when the coupling mechanisms 10, 110, and 210 are in the open position, the coupling mechanisms 10, 110, and 210 use inner sleeves 20, 120, and 220 to prevent the re-engagement of at least one ball 24, 124, and 224. The invention disclosed herein also covers a solution in which the inner sleeve 320 prevents the outer sleeve 316 from retracting to the closed position when at least one ball 324 is pressed into a recess 314 and through hole 332 of the removable tool head 308. In such a solution, the biasing force of the first elastic element 318 is smaller than the biasing force of the second elastic element 322. This embodiment will be described below with reference to Figures 7 and 8.
[0062] Figure 7 shows a coupling mechanism 310 in a closed position in which the removable tool head 308 is engaged with the cavity 312 of the front end 302 of the power tool 301. In this embodiment, there are 12 balls 324 and 12 recesses 314 within the removable tool head 308, but at least one of these balls 324 is fully pressed into and engaged within the conical through hole 332 and the (single or double) recesses 314. The (single or double) balls 324 are in contact with an inner projection 340 having a flat top.
[0063] The inner sleeve 320 is biased toward the tool-side end 328 of the cavity 312, and a second biasing element 322 is compressed to apply pretension. The inner sleeve 320 includes a pair of protruding elements 348 that penetrate a recess in the front end 302. The protruding elements 348 may be fingers or the like. However, the protruding elements 348 are not arranged continuously in the circumferential direction around the inner sleeve 320, but are designed as fingers, shafts, or board-like elements as described. In the closed position of the coupling mechanism 310 as shown in Figure 7, the protruding element 348 can contact the outer sleeve 316. However, in this case, the removable tool head 308 absorbs the force of the second biasing element 322, so the biasing force of the first biasing element 318 does its job and pushes the outer sleeve 316 toward the tool-side end 328 of the power tool 301 to prevent the (single and double) balls 324 from moving out of the conical through-hole 332 via the inner protrusion 348. Thus, these protruding elements 348 do not put pressure on the outer sleeve 316. Therefore, the movement of the inner sleeve 320 is prevented by the tool head 308 in the closed position. Consequently, the operator needs to push the tool head 308 into the cavity 312 against the biasing force of the second biasing element 322. When the operator wishes to remove the tool head 308 from the power tool, they manually push the outer sleeve 316 toward the free end 330 of the cavity 312, which allows the (single and double) balls 324 to slide from the inner projection 340 toward the inclined surface 338. The pressure generated by the second biasing element 322 causes the (single and double) balls 324 to detach from the recess (314), and as a result, the tool head 308, driven by the second biasing element 322 and the inner sleeve 320, is pushed out of the cavity 312 as shown in Figure 8.
[0064] Figure 8 shows the coupling mechanism 310 in the open position, even though the tool head 308 is still partially fitted into the cavity 312. The first biasing element 322 is extended, pushing the removable tool head 308 out of the cavity 312. The (single or double) protruding elements 348 of the inner sleeve 320 are in contact with the outer sleeve 316, and the biasing force of the second biasing element 322 is greater than that of the first biasing element 318, so that the outer sleeve 316 cannot slide backward toward the tool-side end 328 of the cavity 312, even if the first biasing element 318 is compressed. When ready to insert another tool head, the operator slides the coupling shaft into the cavity 312 and pushes the tool head 8 against the force generated by the second biasing element 322 until the (single or double) balls 324 engage in the recess 314.
[0065] For the protruding element 348 or projection to contact the outer sleeve 316, some form of recess (not visible in Figures 7 and 8) must be provided in the front end 302 of the power tool. In any case, the inner sleeve 320 may include one, two, three, four, or five or more protruding elements 348 and corresponding recesses in the front end 302.
[0066] The inner sleeve 320, as shown with reference to Figures 6 to 8, may further include a shoulder 350 that abuts against the tool-side end of the removable tool head 308 in the closed position of the coupling mechanism 310 as shown in Figure 7, and this shoulder 350 is used to push the removable tool head 308 out of the cavity 312 at least partially when the closed position is released via the outer sleeve 316 and when the coupling mechanism 316 moves from the closed position to the open position.
[0067] Furthermore, the embodiments of the coupling mechanism 310 shown in Figures 6 to 8 can also be incorporated into the embodiments shown in Figures 1 to 5. Some features, such as the number of balls 24, 124, 224, and 324, or the use of inner sleeves 20, 120, 220, and 320 having protruding elements 348, can also be separated.
[0068] In the illustrated embodiment, the first and second biasing elements 18, 118, 218, 318, 22, 122, 222, and 322 are designed to have passages around which to receive the front ends 2, 102, 202, and 302 (first biasing elements), or the shafts of the drive shaft 6 and / or the removable tool head 8, and / or cables that connect the sensors of the front ends 2, 102, 202, and 302 to the electronic equipment of the power tool.
[0069] In the embodiments described herein, the outer sleeves 16, 116, 216, and 316 are arranged around the outside of the front end portions 2, 102, 202, and 302.
[0070] The recesses 14 and 314 shown in the removable tool heads 8 and 308 are preferably inverted cones and V-shapes.
[0071] The minimum diameter of the through holes 32, 132, 232, and 332 is always smaller than the diameter of at least one ball 24, 124, 224, and 324, but in the closed position of the coupling mechanisms 10, 110, 210, and 310, a portion of at least one ball 24, 124, 224, and 324 extends into the cavities 12, 112, 212, and 312, and this portion is selected to engage with the recesses 14 and 314.
[0072] The power tool 1 shown in the illustration is preferably a battery-powered power tool.
Claims
1. Power tools (1,301), - Motor (4) and, - A drive shaft (6) connected to the motor, which defines the longitudinal axis (a), - A front end (2, 102, 202, 302) having at least one through hole (32, 132, 232, 332) and defining a cavity (12, 112, 212, 312) including a tool-side end (28, 128, 228, 328) and a free end (30, 130, 230, 330), wherein the tool-side end (28, 128, 228, 328) is located behind the cavity (12, 112, 212, 312) and the free end (30, 130, 230, 330) is located in front of the cavity (12, 112, 212, 312), and - Coupling mechanisms (10, 110, 210, 310) for releasably connecting a removable tool head (8, 308) to the drive shaft, The coupling mechanism comprises an outer sleeve (16, 116, 216, 316) positioned to at least partially surround the cavity, the coupling mechanism further comprises a first biasing element (18, 118, 218, 318) and at least one ball (24, 124, 224, 324) positioned at least partially within the at least one through hole and inside the outer sleeve, the outer sleeve comprising an inclined inner surface (38, 138, 238, 338) and an inner projection (40, 140, 240, 340) adjacent to the inclined inner surface, and the first biasing The element is positioned at the front end and abuts against the outer sleeve and the front end, and the coupling mechanism is operable by an operator between an open position in which the power tool can receive the removable tool head and a closed position in which the removable tool head is connected to the power tool and locked inside, so that in the open position the at least one ball can be displaced outward away from the longitudinal axis (a), and in the closed position the outward displacement of the at least one ball is prevented by the inner projection of the outer sleeve. The coupling mechanism further includes an inner sleeve (20, 120, 220, 320) at least partially disposed within the cavity, and a second biasing element (22, 122, 222, 322) that abuts against the tool-side end of the cavity and the inner sleeve, thereby preventing the inner protrusion from abutting against the at least one ball in the open position. Insertion of the removable tool head (8,308) into the power tool (1,301) biases the inner sleeve (20,120,220,320) toward the tool-side end (28,128,228,328) of the cavity (12,112,212,312) by the insertion of the removable tool head (8,308) so that the inner sleeve (20,120,220,320) toward the tool-side end (28,128,228,328) of the cavity (12,112,212,312) so that in the closed position the at least one ball (24,124,224,324) engages with at least one recess (14,314) of the removable tool head (8,308) and locks the removable tool head (8,308). (i) The inner sleeve (320) includes at least one protruding element (348) projecting toward the free end (330) of the cavity (312), the protruding element being designed to abut against the outer sleeve (316) at least in the open position, and the biasing force of the first biasing element (318) is less than that of the second biasing element (322), or, the inner sleeve being able to prevent the outer sleeve from being displaced toward the closed position via the at least one protruding element when the removable tool head (308) is not inserted into the power tool. (ii) The inner sleeve (20, 120, 220) includes an outer surface (54) which is positioned to abut against the at least one ball (24, 124, 224) in the open position of the coupling mechanism (10, 110, 210) to prevent the at least one ball from extending inward toward the longitudinal axis (a) into the cavity in the open position. A power tool characterized by the following features.
2. In the closed position, the inner sleeve (20, 120, 220, 320) is biased toward the tool-side end (28, 128, 228, 328) by the removable tool head (8, 308), thereby allowing the at least one ball (24, 124, 224, 324) to be displaced inward toward the longitudinal axis (a) into the through hole (32, 132, 232, 332) by the inner projection (40, 140, 240, 340) of the outer sleeve (16, 116, 216, 316), so that the at least one ball partially extends into the cavity (12, 112, 212, 312) and engages with the at least one recess (14, 314) of the removable tool head, thereby locking the removable tool head into the power tool. The power tool according to claim 1.
3. The inclined inner surfaces (38, 138, 238, 338) are configured to guide the inward displacement of the at least one ball (24, 124, 224, 324) toward the longitudinal axis (a) during the axial displacement of the outer sleeve (16, 116, 216, 316) by the first biasing elements (18, 118, 218, 318), and when the coupling mechanism (10, 110, 210, 310) moves from the open position to the closed position by pushing the removable tool head (8, 308) and the inner sleeve (18, 118, 218, 318) toward the tool-side end (28, 128, 228, 328) of the cavity (12, 112, 212, 312). The power tool according to claim 1.
4. The through holes (32, 132, 232, 332) are conical through holes whose diameter decreases toward the longitudinal axis (a), and are selected such that at least one ball (24, 124, 224, 324) can be positioned within the through hole to partially extend outward from the conical through hole into the cavity (12, 112, 212, 312). The power tool according to claim 1.
5. The first biasing elements (18, 118, 218, 318) include a first passage positioned to at least partially enclose the cavity (12, 112, 212, 312), and the second biasing elements (20, 120, 220, 320) include a second passage designed to receive the drive shaft (6) or the connector of the removable tool head. The power tool according to claim 1.
6. The coupling mechanism (10, 110, 210, 310) includes at least two balls (24, 124, 224, 324) or more, and the number of through holes (32, 132, 232, 332) in the front end (2, 102, 202, 302) and the number of recesses (14, 314) in the removable tool head (8, 308) corresponds to or exceeds the number of balls in the coupling mechanism. The power tool according to claim 1.
7. The inner sleeves (20, 120, 220, 320) include shoulders (50, 350) designed to abut against the tool-side end of the removable tool head in the closed position, the shoulders being designed to push the removable tool head out of the cavity when the outer sleeves (16, 116, 216, 316) are manually displaced against the biasing force of the first biasing elements (18, 118, 218, 318) and when the coupling mechanism (10, 110, 210, 310) moves to the open position. The power tool according to claim 1.
8. The cavity has a generally cylindrical shape and is arranged parallel to the longitudinal axis (a) such that the center line (a) of the cylindrical shape coincides with the longitudinal axis (a) determined by the drive shaft (6). The power tool according to claim 1.
9. The inner sleeves (20, 120, 220, 320) and outer sleeves (16, 116, 216, 316) are configured to move parallel to and concentric with the longitudinal axis (a), respectively, when pushed or pulled manually or by the second biasing elements (22, 122, 222, 322) and the first biasing elements (18, 118, 218, 318). The power tool according to claim 1.
10. The inner sleeve (320) is designed to overcome the biasing force of the second biasing element (322) by displacing toward the tool-side end (328) of the cavity (312) when the removable tool head (308) is inserted toward the tool-side end and manually pushed in, thereby allowing the outer sleeve (316), propelled by the biasing force of the first biasing element (318), to slide into the closed position, first guiding the inclined inner surface (338) and then the inner projection (340) to contact the at least one ball (324), and the at least one ball engaging with the recess (314) on the removable tool head by being pushed into the through hole (332), thereby moving the coupling mechanism (310) into the closed position. The power tool according to claim 1.
11. The inner sleeve (20, 120, 220), and therefore the outer surface (54), displace toward the tool-side end (28, 128, 228) of the cavity (12, 112, 212) when the removable tool head (8) is inserted toward the tool-side end of the cavity and manually pushed in, thereby overcoming the biasing force of the second biasing element (22, 122, 222) by ceasing to contact the at least one ball, and as a result the first biasing element (18, 118, 21 8) The biasing force of the outer sleeve (16, 116, 216) allows the outer sleeve (16, 116, 216) to slide, thereby moving the inclined inner surface (38, 138, 238) away from contact with the at least one ball (24, 124, 224), after which the inner projection (40, 140, 240) comes into contact with the at least one ball, and the at least one ball engages with a recess on the removable tool head, causing the coupling mechanism to move to the closed position. The power tool according to claim 1.
12. The outer sleeve (216) further includes another inclined surface (238) adjacent to the inner projection (240), and the neutral point of the first biasing element (218) is selected such that the inner projection (240) contacts the at least one ball (224) when the first biasing element (218) is at the neutral point corresponding to the closed position of the coupling mechanism (210). The power tool according to claim 1.
13. The inner protrusions (40, 140, 240, 340) extend from the inside of the outer sleeve toward the longitudinal axis (a) and include a flat top (58) which is configured to abut against at least one of the balls (24, 124, 224, 324) in the closed position of the coupling mechanism (10, 110, 210, 310). The power tool according to claim 1.