Screw drive device for use with an impact wrench
The screw drive device addresses bearing damage issues in impact wrenches by using a coupling sleeve with radial holes and a depth control element, enabling free rotation and adjustable depth control, thus extending the screwdriver head's life and improving operational efficiency.
Patent Information
- Application Number
- DE202025104738
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2025-08-13
- Publication Date
- 2025-12-04
- Estimated Expiration
- 2035-08-31
AI Technical Summary
Existing screw-driving devices, particularly those using impact wrenches, cause damage to the circular bearing that secures the screwdriver head, leading to premature replacement due to vibrations.
A screw drive device with a drive shaft and a hollow coupling sleeve that includes radial holes for coupling bearings to securely clamp and release the screwdriver head, allowing it to rotate freely, and a depth control element to manage screw penetration depth, featuring interchangeable parts for adjustable depth control.
Prevents bearing damage by allowing the screwdriver head to rotate freely and control screw depth, extending the life of the screwdriver head and ensuring efficient screw tightening and loosening operations.
Smart Images
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Abstract
Description
Technical field
[0001] The invention relates to a screw drive device, in particular for use with an impact wrench. State of the art
[0002] Devices that use an electrically powered tool (such as an electric drill or impact wrench) to drive screws are common in this field. Taiwanese utility model 098218832, for example, describes a dual-function automatic shut-off device for tightening and loosening screws. It effectively drives electric drills smoothly and continuously. However, the construction industry increasingly uses longer screws (bolts), and electric drills are not efficient for tightening such screws. Therefore, a screw-driving device equipped with an impact wrench is used to tighten long screws. The impact wrench generates the oscillating torque required to tighten a long screw, while the screw-driving device controls the screw's penetration depth into the workpiece to optimize the screw's holding power.
[0003] However, the vibrations caused by the screwdriver drive and the impact wrench can damage the circular bearing of the screwdriver drive, which secures the screwdriver head shaft in the drive position. In this case, the bearing no longer supports the screwdriver head shaft and it can no longer rotate freely in the drive position. Therefore, the screwdriver head must be replaced before the end of its service life. Object of the invention
[0004] The invention relates to a screw drive device for use with an impact wrench, comprising: a drive shaft having a drive end for coupling with and driving by the impact wrench, and an insert end with an annular wall. The annular wall has several radial holes arranged at intervals on a first radial plane of the insert end and at intervals on a second radial plane of the insert end. Each radial hole accommodates a coupling bearing that clamps a screwdriver head in the drive position and releases the screwdriver head in the coupling position, allowing the screwdriver head to rotate freely relative to the drive shaft. Each coupling bearing is a cylindrical body with a round outer end and a frustoconical end for clamping a screwdriver head in the drive position.A hollow coupling sleeve has an upper and a lower end, as well as a central cavity for receiving the drive shaft. The upper end of the central cavity is sized to allow the drive end of the drive shaft to pass through while preventing the insertion end of the drive shaft from passing through. The hollow coupling sleeve has two annular grooves at the lower end of the central cavity. These annular grooves are sized to receive the outer ends of the coupling bearings, which are arranged on a first or second radial plane when the drive shaft is engaged. This allows the corresponding inner ends of the coupling bearings to disengage from the screwdriver head but remain in their respective radial holes. A depth control element is connected to the lower end of the hollow coupling sleeve. This depth control element has a lower section that forms a passage for the screwdriver head.A spring pre-tensions the drive axle into the drive position. Brief description of the drawings
[0005] Features of the present invention are described below with reference to the accompanying drawings. Fig. Figure 1 shows a perspective view of the screw drive device of the invention; Fig. Figure 2 shows an exploded view of the screw drive device 10 according to Fig. 1; Fig. Figure 3 shows an exploded view of a second embodiment of the screw drive device according to Fig. 1; Fig. 4 shows a cross-sectional view along line 4-4 in Fig. 1 of the screw drive device according to Fig. 2; Fig. Figure 5 shows a cross-sectional view along line 4-4 in Fig. 1 of the screw drive device according to Fig. 3; Fig. Figure 6 shows an enlarged view of one of the coupling bearings of the screw drive device according to Fig. 4 or Fig. 5; Fig. Figure 7 shows a cross-sectional view of the screw drive device according to Fig. 4 in the clutch position; Fig. Figure 8 shows a cross-sectional view of the screw drive device according to Fig. 5 in the clutch position; Fig. Figure 9 shows a cross-sectional view of the screw drive device according to Fig. 4 in a locked position for removing a tightened screw. Ways to implement the invention
[0006] Fig. Figure 1 shows a perspective view of the screw drive device 10 of the invention.
[0007] The screw drive device 10 comprises a drive shaft 12. The drive shaft 12 has a drive end 14 which can be coupled to and driven by a handheld electric impact wrench (not shown). The handheld power tool is known.
[0008] A hollow coupling sleeve 16 is attached to the drive shaft 12. A locking projection 17 is provided on one side of the drive shaft 12 to fix the screw drive device 10 in a locked position so that a turned screw can be removed.
[0009] The following description refers to Fig. 9. A depth control element (nose cone) 18 surrounds the lower end of the hollow coupling sleeve 16. The depth control element 18 has a lower section 20. A screwdriver head 22 is inserted through the lower section into a lower end of the drive shaft 12.
[0010] The following description refers to Fig. Reference is made to sections 4 to 8. When the screw drive device 10 is in the drive position, the screwdriver head 22 rotates with the drive shaft 12, and when the screw drive head 10 is in a clutch position, the clamping connection between the screwdriver head 22 and the drive shaft 12 is released.
[0011] The depth control element 18 is interchangeable to change the depth of a screw (bolt) screwed in with the screw drive device 10. If necessary, this can be achieved by adding an additional depth control element 18 with a different height.
[0012] For this purpose, the upper end of the depth control part 18 is provided with an axial slot 24, which allows an inwardly projecting lip 26 of the depth control part 18 to disengage from a correspondingly shaped groove 28 of the hollow coupling sleeve 16 (see, for example, Fig. 4).
[0013] Fig. Figure 2 shows an exploded view of the screw drive device 10 according to Fig. 1.
[0014] The drive end 14 of the drive shaft 12 passes through the central cavity 40 of the hollow coupling sleeve 16. The central cavity 40 has an upper end that forms an inwardly extending flange 42. The flange is dimensioned such that it allows the drive end 14 of the drive shaft 12 to pass through, but not the insert end 44 of the drive shaft 12. The flange 42 is provided with a locking notch 43 into which the locking projection 17 can engage to hold the screw drive device in the locked position. This will be described further below with reference to Fig. 9 described in more detail.
[0015] Several radial holes 46 penetrate the insert end 44 of the drive axle 12 and each accommodate a clutch bearing 50 (see Fig. 4-6). In the present embodiment, three radial holes 46 are arranged radially spaced 120 degrees apart. The coupling bearings 50 clamp the screwdriver head 22 securely in the drive position of the screw drive device. This will be described below with reference to Fig. 4, Fig. 5 and Fig. 6 described. The screwdriver head 22 can be rotated together with the screw drive device 10.
[0016] When the screw drive device 10 is in the engaged position, the clutch bearings 50 and the screwdriver head 22 are separated (this is referred to below). Fig. 7 and Fig. 8 described), so that the screwdriver head is not rotated together with the rotation of the screw drive device 10 in order to control the depth of the screw driven by the screw drive device 10.
[0017] A coil spring 58 has an upper end that is positioned on the lower end 59 of the drive shaft 12. The coil spring 58 has a lower end that rests on the base of the depth control part 18, as shown in the Fig. 4 and Fig. 5 shown. The coil spring 58 presses against the drive shaft 12 in the direction of the drive position of the screw drive device 10.
[0018] A ring-shaped magnet 60 is arranged in a receiving groove 62 of the lower section 20 of the depth control part 18 (see Fig. 4 and Fig. 5) The magnet 60 magnetically attracts a steel screw (not shown) onto the screwdriver head 22 to hold the screw on the screwdriver head 22 until the screw is attracted by the screw drive device 10.
[0019] Fig. Figure 3 shows an exploded view of another embodiment of the screw drive device 10 according to Fig. 1, which is designated 10a. The screw drive device 10a is identical to the one in Fig. 2 described screw drive device 10, except that the drive shaft 12a has an insert end 44a which is longer than the insert end 44 of the drive shaft 12.
[0020] The coupling sleeve 16a is longer than the coupling sleeve 16, and the screwdriver head 22a is also longer than the screwdriver head 22. Fig. 2. The additional lengths of the insert end 44a, the hollow coupling sleeve 16a, and the screwdriver head 22a allow the insertion end 44a of the hollow coupling sleeve 12a, which is provided with several radial holes 48. Each of the radial holes 48 also accommodates a coupling bearing 50, as will be shown below. Fig. 5 and Fig. 8 is described.
[0021] In this embodiment, the radial holes 46 are arranged on a first radial plane and spaced apart from each other by 120 degrees, and the radial holes 48 are arranged on a second radial plane located above the first radial plane and spaced apart from each other by 120 degrees. Each of the radial holes 46 is spaced 60° apart from each of the adjacent radial holes 48.
[0022] Fig. 4 shows a cross-sectional view along line 4-4 in Fig. 1 of the screw drive device according to Fig. 2, wherein the screwdriver head 22 is rotated by the drive shaft 12.
[0023] The end 44 of the drive shaft 12 has an annular wall 64. The annular wall 64 forms a receiving recess 66 that accommodates the screwdriver head 22. The annular wall 64 is penetrated by several radial holes 46 (only one of which is shown in the cross-sectional view, but generally, as mentioned above, there are three radial holes 46).
[0024] In the drive position shown for the screw drive device 10, the radial holes 46 receive the coupling bearings 50 to clamp the flat surfaces of a hexagonal screwdriver head 22. In the Fig. In the coupling position shown in Figure 7, the screwdriver head 22 is loosened. The hollow coupling sleeve 16 is provided with an annular groove 72 at the lower end of the central cavity 40. This annular groove 72 can accommodate the coupling bearings 50 when the screw drive device 10 is in the coupling position, so that the coupling bearings 50 are separated from the screwdriver head 22 but held in the radial holes 46.
[0025] A ball bearing 74 is arranged with a friction fit in an axial hole 76 to support the upper end of the screwdriver head 22 so that the screwdriver head 22 remains in a stationary state and also allows free rotation of the drive shaft 12 when the screw drive device 10 is in the clutch position, as described below. Fig. 7 is described.
[0026] A retaining ring 78, which is arranged in a radial groove 80 at the end of the receiving recess 66, can engage in a groove 81 on the screwdriver head 22 to hold the screwdriver head 22 removably in the receiving recess 66.
[0027] Fig. Figure 5 shows a cross-sectional view along line 4-4 in Fig. 1 of the screw drive device according to Fig. 3 in the drive position, whereby the screwdriver head 22 is rotated by the drive shaft 12.
[0028] The end 44a of the drive shaft 12a has an annular wall 64a. This forms a receiving recess 66a that accommodates the screwdriver head 22a. The annular wall 64a is penetrated by several radial holes 46, 48. (Only one is shown in the cross-sectional view, but as mentioned above, there are generally three radial holes 46 and three radial holes 48).
[0029] The radial holes 46 hold the coupling bearings 50a. When the screw drive device 10a is in the drive position, the radial holes 48 hold the coupling bearings 50b. The coupling bearings 50b can clamp the flat surfaces of a hexagonal screwdriver bit 22a. In the Fig. In the clutch position shown in section 8, loosen the screwdriver head 22a.
[0030] The hollow coupling sleeve 16a is provided at the lower end of the central cavity 40 with two annular grooves 72a, 72b. The two annular grooves 72a, 72b accommodate the corresponding coupling bearings 50a, 50b when the screw drive device 10a is in the coupling position, so that the coupling bearings 50a, 50b release the screwdriver head 22a, but are held in the corresponding radial holes 46, 48.
[0031] A ball bearing 74 is arranged with a friction fit in an axial hole 76 to support the upper end of the screwdriver head 22a. It also allows free rotation of the drive shaft 12a when the screw drive device 10a is in the engaged position, which will be increasingly referred to below. Fig. 8 is described.
[0032] A retaining ring 78, which is arranged in a radial groove 80 at the end of the receiving recess 66, can engage in a groove 81 on the screwdriver head 22 to hold the screwdriver head 22 removably in the receiving recess 66.
[0033] Fig. Figure 6 shows an enlarged view of one of the coupling bearings 50 of the screw drive device according to Fig. 4 or Fig. 5.
[0034] All coupling bearings 50, 50a, 50b have the same size and shape. In one embodiment, the coupling bearing 50 is a cylindrical body with a frustoconical inner end 52 and a round outer end 54. The overall length of the cylindrical body is designated “a”. The round outer end 54 has a length designated “b”, which is one-quarter of the overall length, namely 1 / 4a (or 0.25a). A cylindrical middle section 56 has a length designated “c”, which is half of the overall length, namely 1 / 2a (or 0.5a). The frustoconical inner end 52 has a length of 1 / 4a (or 0.25a). The cylindrical middle section 56 has a diameter of 1a (or 1.0a). The frustoconical end 52 has a flat surface 57 with a diameter designated “e” of 3 / 4 a (or 0.75 a). The round outer end 54 has a radius designated “r” of 1 / 2 a (or 0.5 a).In one embodiment, the coupling bearing 50 has a length of 4 mm and a diameter of 4 mm. The cylindrical middle section has a length of 2 mm. The round outer end has a radius of 2 mm and a length of 1 mm. The frustoconical inner end 52 has a length of 1 mm and the flat surface 57 has a diameter of 3 mm. It is also possible for both ends of the coupling bearing 50 to be frustoconical.
[0035] Fig. Figure 7 shows a cross-sectional view of the screw drive device 10 according to Fig. 4 in the coupling position. In the coupling position, the screwdriver head 22 is released from the corresponding coupling bearings 50, so that the screw 100 is no longer driven by the screw drive device 10.
[0036] When the screw 100 is driven into a working surface 102, the lower section 20 of the depth control part 18 comes into contact with the working surface 102 and the drive shaft 12 slides downwards along the central cavity 40 of the hollow coupling sleeve 16 until the radial holes 46 are aligned with the annular groove 72 of the hollow coupling sleeve 16. A force from the screwdriver head 22, which engages with a screw driven by it, moves the coupling bearings 50 outwards into the annular groove 72.
[0037] As soon as the clutch bearings 50 enter the annular groove 72, they no longer clamp the flat surfaces of the screwdriver head 22, and the screw drive device 10 is in the clutch position. Even if the drive shaft 12 is continuously rotated by the impact wrench, the screwdriver head can no longer turn the screw. The screw-in depth of the screw into the working surface 102 can thus be controlled by the depth control element 18.
[0038] When the downward pressing force on the drive shaft 12 is released by actuating the impact wrench and the screw drive device 10 is removed from the work surface, the coil spring 58 pushes the drive shaft 12 upwards and the screw drive device 10 returns to the position it was in Fig. 4 drive position shown. In this position, the inclined bottom surface 82 of the ring groove 72 presses against the coupling bearings 50, which thus clamp the corresponding flat surfaces of the screwdriver head 22.
[0039] Fig. Figure 8 shows a cross-sectional view of the screw drive device according to Fig. 5 in the coupling position. In the coupling position, the screwdriver head 22a is released from the coupling bearings 50a, 50b, so that the screw 100 is no longer driven by the screw drive device 10a.
[0040] When the screw 100 is driven into a working surface 102, the lower section 20 of the depth control part 18 comes into contact with the working surface 102 and the drive shaft 12a slides downwards along the central cavity 40 of the hollow coupling sleeve 16a until the radial holes 46, 48 are aligned with the annular grooves 72a, 72b of the hollow coupling sleeve 16a. A force from the screwdriver head 22a, which engages with a screw 100 driven by it, moves the coupling bearings 50a, 50b outwards into the annular grooves 72a, 72b.
[0041] As soon as the coupling bearings 50a, 50b engage in the corresponding annular grooves 72a, 72b, they release the flat surfaces of the screwdriver head 22a and the screw drive device 10a enters the coupling position. Even if the drive shaft 12a is continuously rotated by the impact wrench, the screwdriver head 22a remains stationary, and the screw 100 is no longer turned. The screw-in depth of the screw into the working surface 102 can thus be controlled by the depth control element 18.
[0042] When the downward pressing force on the drive shaft 12a is released by actuating the impact wrench and the screw drive device 10a is removed from the work surface, the coil spring 58 pushes the drive shaft 12a upwards and the screw drive device 10a returns to the position it was in Fig. Return to the drive position shown in section 5.
[0043] When the screw drive device 10a returns to the drive position, the inclined bottom surfaces 82a, 82b of the ring grooves 72a, 72b press against the coupling bearings 50a, 50b, which thus clamp the flat surfaces of the screwdriver head 22a.
[0044] Fig. Figure 9 shows a cross-sectional view of the screw drive device 10 according to Fig. 4 in a locked position in the reverse direction for removing a tightened screw from a workpiece.
[0045] The screw drive device 10 is adjusted in the reverse direction in the drive position. The locking projection 17 is engaged against the spring force of the coil spring 58 by the notch 43 (see Fig. 2) moved downwards, as above based on Fig. 2 described. The hollow coupling sleeve is then rotated so that the locking projection 17 on the underside of the inner flange 42 is located at the upper end of the hollow coupling sleeve 16.
[0046] In the reverse drive position, the coupling bearings 50 are located below the annular groove 72 of the hollow coupling sleeve 16 and clamp the corresponding flat surfaces of the screwdriver head 22, so that the rotation of the drive shaft 12 in any direction can drive the screwdriver head in the same direction. The screw drive device 10 can move the hollow coupling sleeve 16 under a stationary drive shaft 12 into the Fig. Turn the drive to position 4 shown until the locking projection 17 is aligned with the notch 43 and is pushed upwards by the coil spring 58. The Fig. 5 and Fig. The embodiment of the invention shown in Figure 8 can be operated in exactly the same way to fix the screw drive device 10a in the drive position in the reverse direction.
Claims
[1] Screw drive device for use with an impact wrench, comprising a drive shaft (12, 12a) having a drive end (14) that can be coupled to and driven by the impact wrench, and an insert end (44, 44a) with an annular wall (64, 64a), wherein the annular wall (64, 64a) forms a receiving recess (66, 66a) for receiving a screwdriver head (22, 22a) and the annular wall (64, 64a) has several radial holes (46) and each of the radial holes (46, 48) receives a coupling bearing (50, 50a, 50b) that can clamp the screwdriver head (22, 22a) in a drive position and release the screwdriver head (22, 22a) in a coupling position; a hollow coupling sleeve (16, 16a) having an upper end, a lower end and a central cavity (40) that receives the drive shaft (12, 12a), wherein the central cavity (40) has an upper end with a size defined for the passage of the drive end (14) of the drive shaft (12, 12a) and prevents the insert end (44, 44a) of the drive shaft (12, 12a) from passing through it, wherein the hollow coupling sleeve (16, 16a) has an annular groove (72, 72a, 72b) at the lower end of the central cavity (40), the annular groove (72, 72a, 72b) having a size defined to receive the coupling bearings (50, 50a, 50b) therein when the drive shaft (12, 12a) is in the coupling position, such that the loosen the screwdriver head (22, 22a) at the frustoconical ends (52) of the clutch bearings (50), but leave it in the corresponding radial holes (46, 48); a depth control part (18) surrounding the lower end of the hollow coupling sleeve (16, 16a), the depth control part (18) having a lower section (20) having a passage through which the screwdriver head (22, 22a) can extend; and a spring (58) that biases the drive shaft (12, 12a) in the direction of the drive position; characterized by , that: The coupling bearings (50, 50a, 50b) each have a cylindrical body with a frustoconical inner end (52) and a circular outer end (54) and are arranged such that they clamp the screwdriver head (22, 22a) in the drive position and the coupling bearings (50) can move from the coupling position to the drive position, wherein the cylindrical body has a total length “a”, the circular outer end (54) has a length “b” which is 1 / 4a, the cylindrical middle section (56) has a length “c” which is 1 / 2a, the frustoconical inner end (52) has a length “d” which is 1 / 4a, the cylindrical middle section (56) has a diameter of 1a, the frustoconical end forms a flat surface which has a diameter “e” which is 3 / 4a, and the circular outer end (54) has a radius “r” has a value of 1 / 2a, wherein the insertion end (44) of the drive shaft (12) has three radial holes (46),the insert end (44) is spaced apart from each other by 120 degrees on a radial plane of the insert end (44), the insert end (44a) of the drive shaft (12a) having three radial holes (46) arranged on a first radial plane of the receiving end (44a), and three radial holes (48) arranged on a second radial plane of the insert end (44a), the second radial plane being separated from the first radial plane, the hollow coupling sleeve (16a) having a first annular groove (72a) and a second annular groove (72b) for receiving the coupling bearings (50a, 50b) which are held in the radial holes (46, 48) arranged on the first and second radial planes when the screw drive device (10a) is in the coupling position, a locking projection (17) being located on one side of the drive shaft (12, 12a) above the insert end (44, 44a) is arranged to serve the screw drive device (10,10a) to fix in the drive position in the reverse direction in order to remove a tightened screw from a workpiece, wherein at least one locking notch (43) is formed at the upper end of the hollow coupling sleeve (16, 16a) and the locking projection (17) can pass through this to fix the screw drive device (10, 10a) in the drive position in the reverse direction, wherein when the locking projection (17) passes through the locking notch (43) and the hollow coupling sleeve (16, 16a) is rotated far enough, the locking projection (17) is held in the hollow coupling sleeve (16, 16a), wherein an axial slot (24) formed at the upper end of the depth control part (18) makes it possible to exchange the depth control part (18) and replace it with another depth control part of a different depth in order to change the depth of a screw driven into a workpiece,wherein the depth control part (18) has a lower section which is smaller than an upper section of the depth control part (18), and wherein each of the radial holes (46) on the first radial plane is spaced 60 degrees apart from each of the adjacent radial holes (48) on the second radial plane. [2] Screw drive device for use with an impact wrench according to claim 1, characterized by, that the lower end of the depth control part is provided with a receiving groove (62) surrounding the interior through which the screwdriver head (22, 22a) extends, wherein an annular magnet (60) is arranged in the receiving groove (62) to hold the lower end of the screwdriver head (22, 22a) when the drive shaft (12, 12a) is in the drive position, wherein an annular groove (80) is formed on the lower part of the insert end (44, 44a) of the drive shaft (12, 12a), wherein the annular groove (80) receives a retaining ring (78) which engages with the screwdriver head (22, 22a) to releasably hold the screwdriver head (22, 22a) on the insert end (44, 44a) of the drive shaft (12, 12a), wherein the depth control part (18) has an axial slot (24) has a feature formed at the upper end of the depth control part, which makes it possible to detach the depth control part (18) from the hollow coupling sleeve (16, 16a),so that the depth control collar (18) is removed from the hollow coupling sleeve (16, 16a).