An automatic screwdriver bit mounting shaft structure

Abstract

This invention discloses an automatic screwdriver bit mounting shaft structure, including a shaft body. The rear end of the shaft body is provided with a motor connection part for connecting to the drive shaft of a screwdriver motor. The front end of the shaft body is provided with a bit mounting part extending axially. The side wall of the bit mounting part is provided with a central rectangular groove extending axially. The central rectangular groove is used to mate with the central flat part of a central flat bit. This invention integrates three independent torque transmission structures—a central rectangular groove, an eccentric rectangular groove, and an end rectangular groove—on the same mounting shaft, which can simultaneously adapt to three mainstream bit types: central flat, notched, and double-ear. Different types of bits can be freely switched without changing the mounting shaft, simplifying the operation process, improving work efficiency, and reducing the number of accessories, thus lowering usage and management costs.

Description

Technical Field

[0001] This invention relates to the field of power tool accessories technology, specifically to a mounting shaft structure for an automatic screwdriver bit. Background Technology

[0002] Electric screwdrivers (commonly known as "electric screwdrivers") are basic fastening tools widely used in industrial assembly, electronics manufacturing, and home appliance repair. They are adapted for tightening and loosening various screws by changing the size and head shape of the bits. The connection structure between the bit and the drive shaft of the electric screwdriver motor is the core component that determines the torque transmission efficiency, tightening accuracy, working stability, and service life.

[0003] Currently, the mainstream screwdriver bit tail connection types on the market mainly include three types: hexagonal shank, notched shank (also known as D-shaped shank), and double-eared shank. Correspondingly, the mounting shafts of electric screwdrivers are designed with internal hexagonal holes, eccentric grooves, and double-eared end grooves to achieve torque transmission. These connection types have become industry standards after long-term development, but the following technical defects still exist in actual use: (1) The tail-notch bit adopts a single-sided plane force, and the torque application point is deviated from the central axis of the bit. When rotating at high speed, it is easy to generate eccentric wobbling, which leads to a decrease in tightening accuracy. Moreover, long-term use will cause uneven wear between the bit and the mounting shaft. Although the hexagonal shank bit has multi-face contact, it is limited by the machining accuracy, and the actual force is still uneven. The torque application point of the double-ear shank bit is located at the end of the bit, and the lever arm is short. Under high torque conditions, it is easy to deform or break.

[0004] (2) Existing electric screwdriver mounting shafts can usually only be used with a single type of screwdriver bit. When users need to use screwdriver bits with different connection types, they must replace the corresponding mounting shaft. This is cumbersome, seriously affects work efficiency, and increases the cost of spare parts procurement and the difficulty of inventory management.

[0005] (3) To solve the problem of torque transmission eccentricity in existing bits, there is a type of bit with a flat center (straight-line shape). Its torque application point is located on the central axis of the bit, resulting in smoother rotation and higher tightening accuracy. However, all general-purpose mounting shafts on the market cannot be directly used to install this new bit, which limits its widespread application.

[0006] To address the shortcomings of the existing technology, this invention proposes a new type of screwdriver bit mounting shaft, which can reliably install the new type of flat-position screwdriver bit and is compatible with the existing mainstream notched and double-ear screwdriver bits, effectively solving the problems existing in the prior art. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: an automatic screwdriver bit mounting shaft structure, including a shaft body, a motor connection part for connecting to the drive shaft of a screwdriver motor at the rear end of the shaft body, a bit mounting part extending axially at the front end of the shaft body, and a central rectangular groove extending axially on the side wall of the bit mounting part, the central rectangular groove being used to cooperate with the central flat part of the central flat bit.

[0008] Furthermore, the centerline of the intermediate rectangular groove is coplanar with the axis of the shaft body, and the intermediate rectangular groove is arranged radially symmetrically along the bit mounting portion.

[0009] Furthermore, the inner wall of the bit mounting part is provided with an eccentric rectangular groove extending along the axial direction. The center line of the eccentric rectangular groove is not coplanar with the axis of the shaft body. The eccentric rectangular groove is used to cooperate with the tail notch of the notch bit.

[0010] Furthermore, the front end face of the shaft body is provided with an end rectangular groove, which is used to cooperate with the two ears of the double-ear screwdriver bit.

[0011] Furthermore, at least one steel ball mounting hole is provided on the front end side wall of the shaft body for mounting a steel ball to secure the screwdriver bit.

[0012] The advantages of this invention compared to the prior art are: (1) The present invention provides an axially extending intermediate rectangular groove on the inner wall of the bit mounting hole of the mounting shaft, which fits with the intermediate flat part of the intermediate flat bit; the torque is directly applied to the central axis of the bit through the two side walls of the rectangular groove, and the force is symmetrical and uniform, thus eliminating the problem of eccentric shaking.

[0013] (2) The present invention integrates three independent torque transmission structures—the middle rectangular groove, the eccentric rectangular groove, and the end rectangular groove—on the same mounting shaft. It can simultaneously adapt to three mainstream bit types: the middle flat position, the tail notch, and the double ear. Different types of bits can be freely switched without changing the mounting shaft, which simplifies the operation process, improves work efficiency, and reduces the number of accessories, thereby reducing the cost of use and management.

[0014] (3) The mounting shaft of the present invention can be realized by adding a corresponding rectangular groove through milling on the basis of the existing general mounting shaft. There is no need to change the overall shape of the mounting shaft, the connection structure with the electric screwdriver motor, and the bit fixing structure (steel ball mounting hole). The processing technology is mature and can directly replace the original mounting shaft of the existing electric screwdriver. No modification is required to the electric screwdriver itself, which is convenient for large-scale production and rapid promotion and application.

[0015] (4) The mounting shaft of the present invention is applicable to most brands and models of electric screwdrivers, pneumatic screwdrivers and manual screwdrivers on the market. It can be used as a standard configuration for new products or as an upgrade accessory for old products, and has a wide market application prospect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an embodiment 1 of the automatic screwdriver bit mounting shaft structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the central rectangular groove in Embodiment 1 of the automatic screwdriver bit mounting shaft structure of the present invention.

[0018] Figure 3 This is a schematic diagram of embodiment 2 of the automatic screwdriver bit mounting shaft structure of the present invention.

[0019] Figure 4 This is a schematic diagram of the eccentric rectangular groove in Embodiment 2 of the automatic screwdriver bit mounting shaft structure of the present invention.

[0020] Figure 5 This is a schematic diagram of the middle rectangular groove in Embodiment 2 of the automatic screwdriver bit mounting shaft structure of the present invention.

[0021] In the attached diagram, 1-shaft body; 101-motor connection part; 2-bite mounting part; 3-middle rectangular groove; 4-eccentric rectangular groove; 5-end rectangular groove; 6-ball mounting hole. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] In the description of the embodiments of the present invention, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0024] Furthermore, the use of terms such as "horizontal," "vertical," and "sag" does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of the present invention, "multiple" means at least two.

[0026] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0027] Example 1 (Single-function intermediate flat bit adapter shaft) This embodiment provides a screwdriver bit mounting shaft, including a shaft body 1, which is a cylindrical metal shaft. Its rear end has a motor connection part 101 (such as an external spline, internal hexagon, or threaded connection) that connects to the screwdriver motor drive shaft, and its front end has a cylindrical bit mounting part 2 extending axially inward. The side wall of the bit mounting part 2 has an axially extending central rectangular groove 3. The centerline of the central rectangular groove 3 is coplanar with the axis of the shaft body 1 and is symmetrically arranged radially along the bit mounting part 2. The width of the central rectangular groove 3 matches the thickness of the central flat part of the central flat bit, its depth is greater than the height of the central flat part, and its length is not less than the axial length of the central flat part.

[0028] The front end side wall of the shaft body 1 is provided with two symmetrically distributed steel ball mounting holes 6. The steel ball mounting holes 6 are used to install steel balls and retaining springs to secure the bit, thereby achieving axial positioning of the bit and preventing the bit from falling off during operation.

[0029] In use, insert the tail of the flat-position bit into the bit mounting part 2, aligning the flat-position bit shaft with the central rectangular slot 3. When the shaft body 1 rotates under the drive of the motor, the two side walls of the central rectangular slot 3 directly act on the two planes of the flat-position bit, transmitting torque to the flat-position bit 7. Since the torque application point is located on the central axis of the bit, the bit is subjected to uniform force during rotation, without eccentric wobbling, significantly improving tightening accuracy and service life.

[0030] Example 2 (Universal Triple-Use Screwdriver Bit Mounting Shaft) like Figure 2As shown, this embodiment is an improvement on embodiment 1, and its difference from embodiment 1 is as follows: The inner wall of the bit mounting section 2 is also provided with an axially extending eccentric rectangular groove 4. The center line of the eccentric rectangular groove 4 is not coplanar with the axis of the shaft body 1, and its radial offset matches the eccentricity of the tail notch of the bit. The axial position of the eccentric rectangular groove 4 is located outside the intermediate rectangular groove 3, and the two do not interfere with each other axially. The front end face of the shaft body 1 is provided with an end rectangular groove 5, which is radially through the shaft body 1. The width of the end rectangular groove 5 is adapted to the thickness of the two ears of the double-ear bit, and the depth is not less than the height of the two ears.

[0031] This embodiment can be adapted to three mainstream bit types simultaneously: (1) Adapted to the middle flat bit: exactly the same as in Example 1, the middle flat bit is inserted into the middle rectangular groove to transmit torque.

[0032] (2) Adapting the notched bit: Insert the notched bit into the bit mounting part 2, so that the notch at the end of the bit is aligned and snapped into the eccentric rectangular groove 4. When the shaft body 1 rotates, the side wall of the eccentric rectangular groove 4 drives the notch to rotate, thereby realizing torque transmission.

[0033] (3) Adapting the double-ear bit: Insert the tail of the double-ear bit into the bit mounting part 2, so that the double ears of the bit shank are aligned and snapped into the end rectangular groove 5. When the shaft body 1 rotates, the two end faces of the end rectangular groove 5 drive the double ears to rotate, thereby realizing torque transmission.

[0034] This embodiment integrates three different torque transmission structures on the same mounting shaft, achieving compatibility with three mainstream bit types on the market with a single shaft. This greatly improves the versatility of the screwdriver and reduces the cost and time required for users to change the mounting shaft when switching to different bits. All standard parts used in this invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0035] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A drive shaft structure of an automatic screwdriver bit, characterized by: The device includes a shaft body, the rear end of which is provided with a motor connection part for connecting to the drive shaft of a screwdriver motor, and the front end of which is provided with a bit mounting part extending axially. The side wall of the bit mounting part is provided with a central rectangular groove extending axially, and the central rectangular groove is used to cooperate with the central flat part of the central flat bit.

2. The chuck structure of an automatic screwdriver bit according to claim 1, wherein: The centerline of the intermediate rectangular groove is coplanar with the axis of the shaft body, and the intermediate rectangular groove is arranged symmetrically along the radial direction of the bit mounting part.

3. The chuck structure of an automatic screwdriver bit according to claim 1, wherein: The inner wall of the bit mounting part is also provided with an eccentric rectangular groove extending along the axial direction. The center line of the eccentric rectangular groove is not coplanar with the axis of the shaft body. The eccentric rectangular groove is used to cooperate with the tail notch of the bit.

4. The mounting shaft structure for an automatic screwdriver bit according to claim 1 or 3, characterized in that: The front end face of the shaft body is provided with an end rectangular groove, which is used to cooperate with the two ears of the double-ear screwdriver bit.

5. The mounting shaft structure for an automatic screwdriver bit according to claim 1, characterized in that: The front end sidewall of the shaft body is provided with at least one steel ball mounting hole for mounting a steel ball to secure the screwdriver bit.

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