Screwing tool for screwing fasteners

Abstract

The utility model discloses a screwing tool for screwing a fastener, which comprises an input shaft, an output shaft and a gear mechanism, and the gear mechanism at least comprises a driving gear and a driven gear; the input shaft extends in the axial direction, the first end of the input shaft is fixedly connected to the driving gear on the first side of the gear mechanism, and the second end of the input shaft is detachably connected to the driving source so that the input shaft and the driving gear can rotate under driving of the driving source. The output shaft extends in the direction parallel to the axial direction, the first end of the output shaft is fixedly connected to a driven gear of the gear mechanism on the second side, opposite to the first side, of the gear mechanism so as to be driven by the driving gear to rotate, and the second end of the output shaft is detachably connected with a fastener so as to screw the fastener when the output shaft rotates; the input shaft and the output shaft are offset by a predetermined distance in a radial direction perpendicular to the axial direction. The screwing tool disclosed by the utility model can avoid obstacles in a limited operation space so as to implement screwing operation of a fastener.

Description

Technical Field

[0001] The present disclosure generally relates to the technical field of mechanical manufacturing. In particular, the present disclosure relates to a screwing tool for screwing a fastener. More specifically, the present disclosure relates to a screwing tool capable of avoiding obstacles to screw a fastener when an operating space is limited. Background Art

[0002] In some industrial production, it is usually necessary to use fasteners (such as screws, bolts, etc.) to perform pre-tightening or tightening operations on some parts (such as the fuel tank bracket of a vehicle). However, in some cases, the operation of these fasteners is difficult to implement due to space limitations. For example, an obstacle (which may be a structural member of the component itself or other parts located around the component) may be located near the part for installing the fastener (for example, above the part for installing the fastener and at a close distance), making it impossible for conventional screwing tools to approach the part for installing the fastener, and therefore making it impossible to use conventional screwing tools to perform screwing operations on the fasteners. Even if the operation is performed reluctantly, there is a risk of damaging the fastener.

[0003] For example, during the assembly of a vehicle, a pre-tightening operation may be required on a fuel tank bracket of the vehicle. Since the space between the fuel tank bracket and the surrounding parts is too small, the sleeve and / or extension rod of a conventional screwing tool cannot approach the position for installing the fastener to screw the fastener.

[0004] Therefore, in production practice, there is a need for a screwing tool for screwing a fastener, which can at least avoid obstacles in a limited operating space to perform the screwing operation of the fastener. Utility Model Content

[0005] One of the objectives of the present disclosure is to provide a screwing tool for screwing fasteners, which can at least solve one of the technical problems mentioned above (for example, it can avoid obstacles in a limited operating space to perform a screwing operation on the fastener) or achieve other additional advantages.

[0006] In some embodiments, a screwing tool for screwing a fastener is provided, the screwing tool comprising an input shaft, an output shaft and a gear mechanism, the gear mechanism comprising at least a driving gear and a driven gear; wherein the input shaft extends along an axial direction and has a first end and a second end, the first end of the input shaft is fixedly connected to the driving gear of the gear mechanism on a first side of the gear mechanism, and the second end of the input shaft is removably engageable to a driving source so that the input shaft and the driving gear can rotate under the drive of the driving source; wherein the output shaft extends along a direction parallel to the axial direction and has a first end and a second end, the first end of the output shaft is fixedly connected to the driven gear of the gear mechanism on a second side of the gear mechanism opposite to the first side so as to rotate under the drive of the driving gear, and the second end of the output shaft is removably engageable with the fastener to screw the fastener when the output shaft rotates; and wherein the input shaft and the output shaft are offset by a predetermined distance in a radial direction perpendicular to the axial direction.

[0007] In some embodiments, the gear mechanism includes a first gear, a second gear and a third gear, the first gear is the driving gear, the third gear is the driven gear, and the second gear is placed between the first gear and the third gear, the first end of the input shaft is fixedly connected to the first gear of the gear mechanism on a first side of the gear mechanism, the first end of the output shaft is fixedly connected to the third gear of the gear mechanism on a second side of the gear mechanism opposite to the first side, the first gear meshes with the second gear, and the second gear meshes with the third gear, so that the first gear and the third gear rotate in the same direction.

[0008] In some embodiments, the first gear, the second gear, and the third gear have the same pitch circle diameter, so that the first gear and the third gear have the same rotation speed.

[0009] In some embodiments, the first gear is configured with a through hole with a polygonal cross-section, the first end of the input shaft has a section with a polygonal cross-section, and the through hole with a polygonal cross-section is fitted on the section with a polygonal cross-section of the first end of the input shaft.

[0010] In some embodiments, the third gear is configured with a through hole with a polygonal cross-section, the first end of the output shaft has a section with a polygonal cross-section, and the through hole with a polygonal cross-section is fitted on the section with a polygonal cross-section of the first end of the output shaft.

[0011] In some embodiments, the screwing tool further comprises a housing, wherein the housing comprises a gear box housing, and the gear box housing is used to accommodate and support the driving gear and the driven gear.

[0012] In some embodiments, the screwing tool further includes a housing, wherein the housing includes a gear box housing, and the gear box housing is used to accommodate and support the first gear, the second gear, and the third gear.

[0013] In some embodiments, the gear mechanism further comprises a shaft pin, the second gear is mounted on the shaft pin, and both ends of the shaft pin are supported in the gear box housing.

[0014] In some embodiments, the housing further comprises an input shaft housing having a first end and a second end, wherein the first end of the input shaft housing is fixedly connected to the gearbox housing, and the second end of the input shaft housing is fixedly connected to the housing of the driving source.

[0015] In some embodiments, the second end of the input shaft housing has a tooth-shaped feature portion, and the tooth-shaped feature portion matches the shape of the housing of the driving source so that the input shaft housing cannot rotate relative to the housing of the driving source.

[0016] In some embodiments, an axial position limiting member is provided at the second end of the input shaft housing; the axial position limiting member is roughly in the shape of a cup, and an opening is provided at the bottom of the cup, and the input shaft housing passes through the opening; the mouth of the cup faces the direction of the driving source, so that the axial position limiting member accommodates the end portion of the second end of the input shaft housing; the diameter of the opening is smaller than the diameter of the end portion of the second end of the input shaft housing, so that the end portion of the second end of the input shaft housing will not slip out of the opening.

[0017] In some embodiments, an internal thread is provided at the mouth of the cup, and the internal thread is used to be connected to the external thread of the housing of the driving source.

[0018] In some embodiments, the input shaft and / or the output shaft are supported by ball bearings, which are mounted in the housing.

[0019] In some embodiments, the screwing tool further includes a tension spring, which is arranged to be sleeved on the input shaft, and one end of the tension spring is fixed to the inner ring of the ball bearing, and the other end of the tension spring is fixed to the input shaft, so that the input shaft is axially elastically supported on the ball bearing.

[0020] In some embodiments, two tension springs are provided, and the two tension springs are symmetrically arranged.

[0021] In some embodiments, a screwing sleeve is disposed at the second end of the output shaft, the screwing sleeve being configured to engage and screw the fastener.

[0022] In some embodiments, a magnet is disposed at the bottom of the screw sleeve.

[0023] The screwing tool of the utility model can at least avoid obstacles in a limited operating space to implement the screwing operation of the fastener.

[0024] Other features and advantages of the subject technology of the present disclosure will be set forth in the following description, and in part will be apparent from the description, or can be learned by practicing the subject technology of the present disclosure. The advantages of the subject technology of the present disclosure will be realized and obtained through the structures particularly pointed out in the written description and its claims and the accompanying drawings.

[0025] It should also be noted that various aspects of the present disclosure described for one embodiment may be incorporated into other different embodiments, although not specifically described for the other different embodiments. In other words, all embodiments and / or features of any embodiment may be combined in any manner and / or combination, as long as they are not mutually contradictory. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Aspects of the present disclosure will be better understood after reading the following detailed description in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a side view of a screwing tool for screwing a fastener according to one embodiment of the present disclosure, wherein an obstacle and a fastener are also shown;

[0028] Figure 2 is a side cross-sectional view of a screwing tool for screwing a fastener according to an embodiment of the present disclosure, the viewing angle of which is relative to Figure 1 Rotate 180 degrees;

[0029] Figure 3 is a top view of a screwing tool for screwing a fastener according to one embodiment of the present disclosure;

[0030] Figure 4A is a perspective view of a screwing sleeve of a screwing tool according to one embodiment of the present disclosure;

[0031] Figure 4B yes Figure 4A A bottom view of the screw sleeve;

[0032] Figure 4C yes Figure 4A A top view of a screw sleeve;

[0033] Figure 4D is along Figure 4C A cross-sectional view of the screw sleeve cut along the CC direction;

[0034] Figure 4E is along Figure 4C A partial cross-sectional enlarged view of the screw sleeve cut along the EE direction;

[0035] Figure 5A is a perspective view of an input shaft housing of a screwing tool for screwing a fastener according to one embodiment of the present disclosure;

[0036] Figure 5B yes Figure 5A A side view of an input shaft housing;

[0037] Figure 5C yes Figure 5A A bottom view of the input shaft housing;

[0038] Figure 5D yes Figure 5A A top view of an input shaft housing;

[0039] Figure 5E is along Figure 5D A cross-sectional view of the input shaft housing cut along the DD direction;

[0040] Fig. 6A is a perspective view of a fastener according to one embodiment of the present disclosure;

[0041] Figure 6B yes Fig. 6A A top view of a fastener;

[0042] Figure 6C is along Figure 6B A cross-sectional view of the fastener cut along the CC direction;

[0043] Fig.6D yes Fig. 6A a side view of a fastener;

[0044] Fig. 7A is a perspective view of a gear box cover of a screwing tool for screwing a fastener according to one embodiment of the present disclosure;

[0045] Figure 7B yes Fig. 7A A three-dimensional view of the gear box cover from another direction;

[0046] Figure 7C yes Fig. 7A A top view of the gearbox cover;

[0047] Fig.7D is along Figure 7C A cross-sectional view of the gear case cover cut along the CC direction;

[0048] Fig. 7E is along Figure 7C A cross-sectional view of the gearbox cover cut along the DD direction;

[0049] Figure 7F is along Figure 7C A cross-sectional view of the gearbox cover cut along the EE direction;

[0050] Fig. 8A is a perspective view of a gear box body of a screwing tool for screwing a fastener according to an embodiment of the present disclosure;

[0051] Figure 8B yes Fig. 8A A bottom view of the gearbox body;

[0052] Figure 8C yes Fig. 8A A side view of a gearbox body;

[0053] Fig.8D yes Fig. 8A A top view of the gearbox body;

[0054] Fig. 8E is along Fig.8D A cross-sectional view of the gearbox body cut along the CC direction;

[0055] Figure 8F is along Fig.8D A cross-sectional view of the gearbox body cut along the DD direction;

[0056] Figure 8G yes Fig. 8E A partial enlarged cross-sectional view of a gearbox body;

[0057] Fig. 9A is a side view of an input shaft of a screwing tool for screwing a fastener according to one embodiment of the present disclosure;

[0058] Fig. 9B is along Fig. 9A A cross-sectional view of the input shaft cut along the CC direction;

[0059] Fig. 9C is along Fig. 9A The cross-sectional view of the input shaft cut along the DD direction;

[0060] Fig. 10A is a top view of a gasket of a screwing tool for screwing a fastener according to one embodiment of the present disclosure;

[0061] Fig. 10B is along Fig. 10A A cross-sectional view of the gasket cut along the CC direction;

[0062] Fig.11 1 is an assembly diagram of a first gear, a second gear, and a third gear of a screwing tool for screwing a fastener according to an embodiment of the present disclosure.

[0063] It should be understood that like reference numerals refer to like elements throughout the drawings. In the drawings, the dimensions of certain features may be varied and not drawn to scale for clarity. DETAILED DESCRIPTION

[0064] The present disclosure will be described below with reference to the accompanying drawings, wherein the accompanying drawings illustrate several embodiments of the present disclosure. However, it should be understood that the present disclosure can be presented in a variety of different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and fully illustrate the scope of protection of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.

[0065] It should be understood that the terms used in the specification are only used to describe specific embodiments and are not intended to limit the present disclosure. All terms (including technical terms and scientific terms) used in the specification have the meanings commonly understood by those skilled in the art unless otherwise defined. For the sake of simplicity and / or clarity, well-known functions or structures may not be described in detail.

[0066] The singular forms "a", "the" and "the" used in the specification include the plural forms unless clearly indicated. The terms "include", "comprise" and "contain" used in the specification indicate the presence of the claimed features, but do not exclude the presence of one or more other features. The term "and / or" used in the specification includes any and all combinations of one or more of the relevant listed items. The terms "between X and Y" and "between approximately X and Y" used in the specification should be interpreted as including X and Y. The term "between approximately X and Y" used in this specification means "between approximately X and approximately Y", and the term "from approximately X to Y" used in this specification means "from approximately X to approximately Y".

[0067] In the specification, when an element is said to be "on", "attached", "connected", "coupled", or "contacting" another element, the element may be directly on, attached, connected, coupled, or contacting another element, or there may be an intermediate element. In contrast, when an element is said to be "directly" "on", "directly attached", "directly connected", "directly coupled", or "directly contacting" another element, there will be no intermediate element. In the specification, a feature is arranged "adjacent" to another feature, which may refer to a feature having a portion that overlaps with an adjacent feature or a portion that is located above or below an adjacent feature.

[0068] In the specification, spatial relational terms such as "upper", "lower", "left", "right", "front", "back", "higher", "lower", etc. may describe the relationship of one feature to another feature in the drawings. It should be understood that the spatial relational terms include different orientations of the device in use or operation in addition to the orientation shown in the drawings. For example, when the device in the drawings is turned over, features previously described as being "below" other features may now be described as being "above" the other features. The device may also be oriented in other ways (rotated 90 degrees or in other orientations), and the relative spatial relationships will be interpreted accordingly.

[0069] The utility model provides a screwing tool for screwing fasteners, which can avoid obstacles in a limited operating space to implement the screwing operation of the fasteners. Figure 1 , because the obstacle 4 is located above the part for installing the fastener 3 and the distance is relatively close, the conventional screwing tool cannot approach the fastener 3 from above, and the screwing operation cannot be completed using the conventional screwing tool. However, the operator can use the screwing tool described in this article to avoid the obstacle 4 and perform the screwing operation of the fastener 3. The specific structure of the screwing tool of the utility model will be described in detail with reference to the accompanying drawings.

[0070] like Figure 1 and Figure 2 As shown, for tightening the fastener 3 (for example, Figure 6A-6D ) of the screwing tool may include an input shaft 11 (e.g., Figure 9A-9C ), output shaft 13 (for example, Figure 4A-4E) and a gear mechanism 5. The gear mechanism 5 may include at least a driving gear and a driven gear. The input shaft 11 may extend in an axial direction and have a first end and a second end, the first end of the input shaft 11 may be fixedly connected to the driving gear of the gear mechanism 5 at a first side of the gear mechanism 5, and the second end of the input shaft 11 may be removably engaged to a driving source (not shown) so that the input shaft 11 and the driving gear can rotate under the drive of the driving source. The output shaft 13 may extend in a direction parallel to the axial direction and have a first end and a second end, the first end of the output shaft 13 may be fixedly connected to the driven gear of the gear mechanism 5 at a second side opposite to the first side of the gear mechanism 5 to rotate under the drive of the driving gear, and the second end of the output shaft 13 may be removably engaged with the fastener 3 to screw the fastener when the output shaft 13 rotates. Wherein, the input shaft 11 and the output shaft 13 are offset by a predetermined distance in a radial direction perpendicular to the axial direction.

[0071] In some embodiments, Fig.11 As shown, the gear mechanism 5 may include a first gear 111, a second gear 121, and a third gear 131, wherein the first gear 111 is a driving gear, the third gear 131 is a driven gear, and the second gear 121 is disposed between the first gear 111 and the third gear 131. The first end of the input shaft 11 may be fixedly connected to the first gear 111 at a first side of the gear mechanism 5. The first end of the output shaft may be fixedly connected to the third gear 131 at a second side of the gear mechanism 5 opposite to the first side. The first gear 111 meshes with the second gear 121, and the second gear 121 meshes with the third gear 131, so that the first gear 111 and the third gear 131 rotate in the same direction.

[0072] In some embodiments, the first gear 111, the second gear 121, and the third gear 131 may have the same pitch circle diameter, thereby having a transmission ratio of 1:1:1, so that the first gear 111 and the third gear 131 have equal rotation speeds. In other embodiments, the first gear 111, the second gear 121, and the third gear 131 may also have other different pitch circle diameter ratios, thereby having different transmission ratios.

[0073] In some embodiments, Fig.11 As shown, the first gear 111 may be configured with a through hole with a polygonal cross section, the first end of the input shaft 11 may have a section with a polygonal cross section, and the through hole with a polygonal cross section of the first gear 111 is fittedly mounted on the section with a polygonal cross section of the first end of the input shaft 11, so that the first gear 111 cannot rotate relative to the input shaft 11. In other embodiments, the through hole of the first gear 111 and the section of the first end of the input shaft 11 may have other matching cross-sectional shapes.

[0074] In some embodiments, Fig.11 As shown, the third gear 131 may be configured with a through hole with a polygonal cross section, the first end of the output shaft 13 may have a section with a polygonal cross section, and the through hole with a polygonal cross section of the third gear 131 is matchedly mounted on the section with a polygonal cross section of the first end of the output shaft 13, so that the third gear 131 cannot rotate relative to the output shaft 13. In other embodiments, the through hole of the third gear 131 and the section of the first end of the output shaft 13 may have other matching cross-sectional shapes.

[0075] See below for more information Figure 1 and Figure 2 In some embodiments, the screwing tool for screwing the fastener 3 may further include a housing 2. The housing 2 may include a gearbox housing 25, which may be used to accommodate and support the driving gear and the driven gear. In some embodiments, the gear mechanism 5 may further include an axle pin 12, and the second gear 121 is mounted on the axle pin 12. Both ends of the axle pin 12 are supported in the gearbox housing 25.

[0076] In some embodiments, the gearbox housing 25 includes a gearbox cover 251 (eg, Figure 7A-7F ) and a gearbox body 252 (e.g., Figure 8A-8G ). In some embodiments, Figure 3 As shown, the gear box cover 251 and the gear box body 252 are connected by countersunk screws 16.

[0077] In some embodiments, the housing 2 may further include an input shaft housing 24 (eg, Figure 5A-5E The input shaft housing 24 has a first end and a second end 21, the first end of the input shaft housing 24 is fixedly connected to the gear box housing 25, and the second end 21 of the input shaft housing 24 is fixedly connected to the housing of the driving source.

[0078] In some embodiments, the second end 21 of the input shaft housing 24 may have a tooth-shaped feature 211 that matches the shape of a housing of the driving source so that the input shaft housing 24 cannot rotate relative to the housing of the driving source.

[0079] In some embodiments, the second end 21 of the input shaft housing 24 may have an axial position limiter (not shown). The axial position limiter may be roughly in the shape of a cup, with an opening provided at the bottom of the cup, through which the input shaft housing 24 passes. The mouth of the cup faces the direction of the drive source, so that the axial position limiter accommodates the end portion of the second end 21 of the input shaft housing 24. The diameter of the opening at the bottom of the cup is smaller than the diameter of the end portion of the second end 21 of the input shaft housing 24, so that the end portion of the second end 21 of the input shaft housing 24 will not slip out of the opening. An internal thread may be provided at the mouth of the cup, and the internal thread is used to connect with the external thread of the housing of the drive source.

[0080] Because the input shaft 11 and the output shaft 13 are offset by a predetermined distance in the radial direction perpendicular to the axial direction, the rotational torque of the driving source generates a force perpendicular to the output shaft 13 and the radial direction on the output shaft 13, and the force generates a shear force on the fastener 3. By arranging the housing 2 to support the output shaft 13, the housing 2 can overcome the force perpendicular to the output shaft 13 and the radial direction, so that the output shaft 13 only outputs a rotational torque without generating additional shear force.

[0081] In some embodiments, the input shaft housing 24 and the gearbox housing 25 are fixedly connected to each other by a fastening structure 26. In other embodiments, the input shaft housing 24 and the gearbox housing 25 may have other fastening methods.

[0082] In some embodiments, the input shaft 11 and / or the output shaft 13 may be supported by a ball bearing 23, which is mounted in the housing 2. In some embodiments, the ball bearing 23 is mounted in the housing 2 near the first end and the second end of the output shaft 13. In some embodiments, the ball bearing 23 is mounted in the housing 2 near the first end and the second end of the input shaft 11. In some embodiments, the spacer 6 (e.g., Figure 10A-10B ) is arranged at the end of the first end of the output shaft 13.

[0083] In some embodiments, the tension spring 27 may be arranged to be sleeved on the input shaft 11, and one end of the tension spring 27 may be fixed on the inner ring of the ball bearing 23, and the other end of the tension spring 27 may be fixed on the input shaft 11, so that the input shaft 11 is axially elastically supported on the ball bearing. When the operator applies a larger axial pressure, the input shaft 11 axially sinks into the housing 2 for a greater length, and when the operator applies a smaller axial pressure, the input shaft 11 axially sinks into the housing 2 for a smaller length. In some embodiments, two tension springs 27 may be provided, and the two tension springs 27 may be symmetrically arranged.

[0084] In some embodiments, the screw sleeve 14 ( Figure 4A-4E) may be disposed at the second end of the output shaft 13. The screwing sleeve 14 is configured to engage and screw the fastener 3. In some embodiments, the screwing sleeve 14 and the output shaft 13 may be integrally formed.

[0085] In some embodiments, the magnet 141 is disposed at the bottom of the screw sleeve 14. The magnetic force between the magnet 141 and the fastener 3 guides the screw sleeve 14 to be sleeved on the fastener 3 for easy screwing.

[0086] Next, combine Figure 1-2 Describes the use of a screwdriving tool for screwing fasteners.

[0087] The second end of the input shaft 11 is engaged to the driving source. The driving source is held in hand, and obstacles 4 are avoided, so that the second end of the output shaft 13 engages the fastener 3. The driving source is actuated, so that the input shaft 11 and the driving gear rotate under the drive of the driving source. The driving gear drives the driven gear to rotate. The output shaft 13 rotates together with the driven gear mounted thereon to screw the fastener 3.

[0088] When the power shaft of the driving source rotates clockwise, the output shaft 13 rotates counterclockwise, thereby loosening the fastener 3 ; when the power shaft of the driving source rotates counterclockwise, the output shaft 13 rotates clockwise, thereby installing the fastener 3 .

[0089] The use process of some other implementation methods described above is as follows:

[0090] Insert the second end of the input shaft 11 into the power shaft of the driving source. At the same time, the toothed feature 211 of the input end 21 of the housing 2 is matched with the shape of the housing of the driving source so that the housing 2 cannot rotate relative to the housing of the driving source; the internal thread of the axial position limiting member is connected with the external thread of the housing of the driving source so that the housing 2 cannot move relative to the housing of the driving source, so that the housing 2 is completely fixed to the housing of the driving source. Hold the driving source, pay attention to avoid obstacles 4, so that the screw sleeve 14 engages the fastener 3. In this process, the magnetic force between the magnet 141 and the fastener 3 guides the screw sleeve 14 to be sleeved on the fastener 3. Actuate the driving source so that the input shaft 11 and the first gear 111 rotate under the drive of the driving source. The first gear 111 drives the second gear 121 to rotate in the opposite direction, and the second gear 121 drives the third gear 131 to rotate in the same direction as the first gear 111. The output shaft 13 rotates together with the third gear 131 mounted thereon to drive the screwing sleeve 14 to rotate, and the screwing sleeve 14 screws the fastener 3 .

[0091] When the power shaft of the driving source rotates clockwise, the output shaft 13 rotates clockwise, thereby installing the fastener 3 ; when the power shaft of the driving source rotates counterclockwise, the output shaft 13 rotates counterclockwise, thereby loosening the fastener 3 .

[0092] Although the exemplary embodiments of the present disclosure have been described, it should be understood by those skilled in the art that various changes and modifications can be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure in essence. Therefore, all changes and modifications are included in the scope of protection of the present disclosure as defined by the claims. The present disclosure is defined by the appended claims, and the equivalents of these claims are also included.

Claims

1. A screwing tool for screwing a fastener, characterized in that: The screwing tool comprises an input shaft, an output shaft and a gear mechanism, wherein the gear mechanism comprises at least a driving gear and a driven gear; wherein the input shaft extends in an axial direction and has a first end and a second end, the first end of the input shaft being fixedly connected to a driving gear of the gear mechanism at a first side of the gear mechanism, and the second end of the input shaft being removably engageable to a driving source so that the input shaft and the driving gear can rotate under the drive of the driving source; wherein the output shaft extends in a direction parallel to the axial direction and has a first end and a second end, the first end of the output shaft being fixedly connected to a driven gear of the gear mechanism at a second side of the gear mechanism opposite to the first side so as to be driven to rotate by the driving gear, and the second end of the output shaft being removably engageable with the fastener so as to screw the fastener when the output shaft rotates; and The input shaft and the output shaft are offset by a predetermined distance in a radial direction perpendicular to the axial direction.

2. The screwing tool for screwing a fastener according to claim 1, characterized in that: The gear mechanism includes a first gear, a second gear and a third gear, the first gear is the driving gear, the third gear is the driven gear, and the second gear is placed between the first gear and the third gear, the first end of the input shaft is fixedly connected to the first gear of the gear mechanism at a first side of the gear mechanism, the first end of the output shaft is fixedly connected to the third gear of the gear mechanism at a second side of the gear mechanism opposite to the first side, the first gear meshes with the second gear, and the second gear meshes with the third gear, so that the first gear and the third gear rotate in the same direction.

3. The screwing tool for screwing a fastener according to claim 2, characterized in that: The first gear, the second gear, and the third gear have the same pitch circle diameter, so that the first gear and the third gear have the same rotation speed.

4. The screwing tool for screwing a fastener according to claim 2, characterized in that: The first gear is provided with a through hole with a polygonal cross section, the first end of the input shaft has a section with a polygonal cross section, and the through hole with a polygonal cross section is fittedly mounted on the section with a polygonal cross section of the first end of the input shaft.

5. The screwing tool for screwing a fastener according to claim 2, characterized in that: The third gear is provided with a through hole with a polygonal cross section, the first end of the output shaft has a section with a polygonal cross section, and the through hole with a polygonal cross section is fittedly mounted on the section with a polygonal cross section of the first end of the output shaft.

6. The screwing tool for screwing a fastener according to claim 1, characterized in that: The screwing tool further comprises a housing, wherein the housing comprises a gear box housing, and the gear box housing is used to accommodate and support the driving gear and the driven gear.

7. The screwing tool for screwing a fastener according to claim 2, characterized in that: The screwing tool further includes a housing, wherein the housing includes a gear box housing, and the gear box housing is used to accommodate and support the first gear, the second gear, and the third gear.

8. The screwing tool for screwing a fastener according to claim 7, characterized in that: The gear mechanism further comprises an axle pin, the second gear is mounted on the axle pin, and both ends of the axle pin are supported in the gear box housing.

9. The screwing tool for screwing a fastener according to claim 8, characterized in that: The housing further includes an input shaft housing having a first end and a second end, wherein the first end of the input shaft housing is fixedly connected to the gearbox housing, and the second end of the input shaft housing is fixedly connected to the housing of the driving source.

10. The screwing tool for screwing a fastener according to claim 9, characterized in that: The second end of the input shaft housing has a tooth-shaped feature portion, and the tooth-shaped feature portion matches the shape of the housing of the driving source so that the input shaft housing cannot rotate relative to the housing of the driving source.

11. The screwing tool for screwing a fastener according to claim 10, characterized in that: An axial position limiting member is provided at the second end of the input shaft housing; the axial position limiting member is roughly in the shape of a cup, and an opening is provided at the bottom of the cup, and the input shaft housing passes through the opening; the mouth of the cup faces the direction of the driving source, so that the axial position limiting member accommodates the end portion of the second end of the input shaft housing; the diameter of the opening is smaller than the diameter of the end portion of the second end of the input shaft housing, so that the end portion of the second end of the input shaft housing will not slip out of the opening.

12. The screwing tool for screwing a fastener according to claim 11, characterized in that: An internal thread is provided at the cup mouth of the cup, and the internal thread is used to be connected with the external thread of the outer shell of the driving source.

13. The screwing tool for screwing a fastener according to claim 6 or 7, characterized in that: The input shaft and / or the output shaft are supported by ball bearings, which are mounted in the housing.

14. The screwing tool for screwing a fastener according to claim 13, characterized in that: The screwing tool also includes a tension spring, which is arranged to be sleeved on the input shaft, and one end of the tension spring is fixed to the inner ring of the ball bearing, and the other end of the tension spring is fixed to the input shaft, so that the input shaft is axially elastically supported on the ball bearing.

15. The screwing tool for screwing a fastener according to claim 14, characterized in that: Two tension springs are provided, and the two tension springs are symmetrically arranged.

16. The screwing tool for screwing a fastener according to claim 1 or 2, characterized in that: A screwing sleeve is disposed at the second end of the output shaft, and the screwing sleeve is configured to engage and screw the fastener.

17. The screwing tool for screwing a fastener according to claim 16, characterized in that: The magnet is arranged at the bottom of the screw sleeve.

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