JPH0818262B2 - Electric screwdriver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric screwdriver.

(Prior Art) Generally, in this type of electric screwdriver, an adjusting sleeve for adjusting a tightening amount (length) of a screw is provided at a tip portion of a housing and is rotated by a drive device. Clutch means is interposed between the gear and a spindle provided with a driver bit projecting from the tip of the adjusting sleeve and movably supported in the axial direction. Is configured to cut off power transmission between the main gear of the main gear and the main shaft on the side of the driver bit, and the clutch means engages both clutch pawls between the fixed side clutch pawl and the movable side clutch pawl. It has been devised to provide a central disc to be disengaged so that its engagement is completely disengaged when the tightening is completed. (See, for example, JP-A-61-219581.) (Problems to be Solved by the Invention) However, in the above-mentioned conventional configuration, when the screw tightening reaches a predetermined amount (length), Although the disc can completely disengage the fixed-side clutch claw and the movable-side clutch claw in the clutch means to reduce the noise such as a metallic sound generated when the claws hit each other as much as possible, the clutch means is used as a central disc. Due to the positive disengagement, the adjustment sleeve is not adjusted properly, and if the screw to be tightened is not tightened to the initially desired tightening amount (length), further tightening will be performed as it is. However, there was a problem that it was not possible to catch up.

Therefore, in view of the above-mentioned conventional drawbacks, the present invention can reduce the noise such as metallic noise generated when the transmission of the clutch means is interrupted as much as possible, and tighten the screw to the initially desired tightening amount (length). The purpose of the present invention is to provide an electric screwdriver that can be tightened even if it is not possible.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides an adjusting sleeve mounted at the tip of a housing so that the position of the housing can be adjusted in the axial direction, and rotating and rotating within the housing. A spindle provided with a main gear that is axially movably supported and rotated by a drive device, and is rotatably and axially movably supported in the housing coaxially with the spindle. And a main shaft provided with a driver bit positioned in the adjusting sleeve, and a fixed clutch portion provided between the main gear and the main shaft and provided on the main gear side, and an axial movement of the main shaft. An electric screwdriver provided with a clutch means which is provided on the main shaft side so as to cooperate with the movable clutch portion and is always biased by a spring in a direction away from the fixed clutch portion. A groove portion is formed in a portion of the clutch means where the movable clutch portion and the main shaft are opposed to each other, and an engaging means that engages with each other in the groove portion to transmit rotation between the movable clutch portion and the main shaft is provided. At least one groove of the groove is provided as a control groove having a displacement amount by which the engaging means is displaced and moved in the axial direction in response to the engagement / disengagement movement of the clutch means. Is provided with an operating means which is connected to the supporting shaft side and presses and urges the supporting shaft side toward the main shaft side and which can be operated from the outer surface of the housing. The gist is that the urging force for urging to the side is set to be weaker than the reaction force of the rotational torque applied to the clutch means.

(Operation) The movable clutch is connected to the fixed clutch portion side through the engaging means that moves in the control groove portion having the axial displacement of the main shaft and the axial displacement of the main shaft or the movable clutch portion. By being pushed against the elastic force and meshed with the fixed clutch portion, the rotation from the drive device is transmitted to the main shaft and the screw tightening is performed by the driver bit.
Then, when the adjusting sleeve mounted on the main body is brought into contact with the surface of the member to be screwed, the main shaft and the movable clutch portion are pushed by the clutch tooth height of the clutch means in the opposite direction to the pushing in the axial direction. When the movable clutch part and the fixed clutch part are disengaged, the rotation transmission is cut off,
At the same time, the elastic force of the spring causes the movable clutch portion to be positively disengaged from the fixed clutch portion by the escape operation of the engaging means along the control groove portion, thereby completing the screw tightening.
When the tightening amount (length) desired at the beginning is not tightened, the supporting shaft side is positively pushed to the main shaft side by the operating means to move the fixed clutch portion on the supporting shaft side to the movable clutch. Engage the part. As a result, the rotation from the drive device can be transmitted to the main shaft, so even if the tightening amount is not tightened to the initially desired tightening amount (length), it is possible to re-tighten, that is, follow-up tightening. To do.

(Example) Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

In the figure, the housing of the electric screwdriver 1
The rear end of the support shaft 2 is rotatably and axially movably supported in the shaft 1a. The support shaft 2 has intermediate gears 5a, 5b at the gear portion 4a of the motor shaft 4 of the drive motor 3. The main gear 6 meshed with the main shaft 6 is fitted into the housing 1a, and a main shaft 8 having a replaceable driver bit 7 inserted and held in the cylindrical portion of the housing 1a rotates on the same axis as the support shaft 2. It is movably supported in the axial direction. The front end of the support shaft 2 is inserted into the rear end of the main shaft 8 to support the front end of the support shaft 2 via a bearing so that the main shaft 8 can rotate and move in the axial direction. The rear end surface of the main shaft 8 faces the main gear 6 with a predetermined gap.

A pair of meshing clutch means 9 is interposed between the main gear 6 and the rear end surface of the main shaft 8, and the clutch means 9 and a fixed clutch claw portion 10 formed on the main gear 6 are provided. , A movable clutch pawl portion 11 that is meshably opposed to the fixed clutch pawl portion 10 and is located at the rear end portion of the main shaft 8.
It consists of and.

The mounting state of the movable clutch claw portion 11 with respect to the rear end portion of the main shaft 8 will be described in detail. A flange portion 12 is integrally formed at the rear end portion of the main shaft 8 and an end surface of the flange portion 12 is formed. A circular recess 13 is formed. Then, on the inner peripheral surface of the circular recess 13, three control groove portions 14 to 14 having a predetermined length are formed at equal intervals in the circumferential direction from the end surface to the bottom surface, and the bottom surface of each control groove portion 14 is As shown in FIG.
A substantially V-shaped inclined surface 14a having the deepest depth in the substantially central portion, that is, an inclined surface 14a having an axial deviation amount is formed.

The movable clutch pawl portion 11 includes a cylindrical portion 11a and a flange portion 11b.
And the cylindrical portion 11a is integrally formed from
Is fitted into the circular recess 13 in a loose fit, and the outer periphery of the cylindrical portion 11a is symmetrical to the control groove portion 14 at a portion facing the control groove portions 14 to 14 so as to overlap. The V-shaped sloped surface 15a that opens the part and is deepest in the center part
The control groove portions 15 to 15 having the bottom surface are also formed in three places. Then, the engagement balls 16 to 16 are fitted in the control grooves 14 to 15 at the fitting positions.

Therefore, the movable clutch claw portion 11 moves in the axial direction of the main shaft 8 and the control groove portions 14 to 14 and 15 to 1 having the axial displacement amount.
The engagement ball 16 in the shaft 5 is moved in the axial direction to engage and disengage the fixed clutch claw portion 10.

It should be noted that the movable clutch pawl 11 is always urged in a direction to be disengaged from the fixed clutch pawl 10 between the support shaft 2 and the movable clutch pawl 11 where the main gear 6 is fitted. Spring 17 is mounted.

As shown in FIGS. 1 and 3, a space 18 for housing an operation lever, which will be described later, is provided substantially above the rear end of the housing 1a.
A horizontal guide piece 18a is formed at the bottom of this void 18.
Are formed and the top is opened. And the void 18
An operating lever 19 is installed inside the operating lever 19
Is guided by the inner wall of the housing 1a and the guide piece 18a so as to be movable back and forth. On the upper surface of the operating lever 19, there is a pushing protrusion 19a exposed from the void 18 of the housing 1a.
Is formed, and the front and rear end surfaces of the pushing projection portion 19a can contact the front and rear surfaces of the empty space so that the front and rear movement range thereof is restricted. Protrusions 19b and 19 are located on the bottom of the operating lever 19
c is projected, and one projection 19c is located on the guide piece 18a.

Also, as shown in FIGS. 2 and 3, the housing 1a
An interlocking piece 20 bent into a substantially crank shape is provided in the rear of the support shaft 2 so as to be movable back and forth similarly to the operating lever 19, and a horizontally extending tip portion 20a thereof is provided.
Is formed in a bifurcated shape, and is abutted to the end surface of the thrust pairing 21 which is arranged along both side portions of the support shaft 2 from the rear end portion of the support shaft 2 and supports the main gear 8. 20b is erected upright and is in contact with the inner surface of the other protrusion 19b of the operating lever 19. A spring 22 is mounted on the lower surface of the operating lever 19 between the rear end 20b of the interlocking piece 20 and the one projection 19c. Then, the interlocking piece 20
Is pushed in the same direction by the elasticity of the spring 22 as the operating lever 19 is pushed forward, and the thrust bearing 21,
The support shaft 2 is moved to the main shaft 8 side via the main gear 8 so that the fixed clutch claw portion 10 meshes with the movable clutch claw portion 11. The elastic force of the spring 22, that is, the spring pressure is set to be slightly weaker than the reaction force of the rotational torque applied to the clutch means 9.

A lock ring 23 is fitted to the outer periphery of the front end of the cylindrical portion of the housing 1a at a predetermined interval, and the lock ring 23 has a desired male screw portion 23a formed on its inner peripheral surface and a rear end. By engaging the locking piece 24 protruding from the housing with the engaging groove 1b of the housing 1a, the locking piece 24 is fixed to the housing 1a. The lock ring 23 is formed with a single slit in the axial direction so that it can be expanded and contracted in the radial direction, and a screw hole 25 is formed in a bulged portion formed in the radial direction of the outer periphery of the slit portion. The tube diameter is expanded and reduced by the photographing screw 26 screwed into the screw hole 25 to lock and release the adjusting sleeve 27 described later.

An adjusting sleeve 27 for adjusting the screw-in depth of a screw to be tightened is fitted between the housing 1a and the lock ring 23 on the outer periphery of the distal end of the cylindrical portion, and the adjusting sleeve 27 is formed into a substantially conical tube shape. The tip thereof extends from the lock ring 23 and rotatably supports the driver bit 7 mounted on the main shaft 8 in the central axis direction. A female screw portion 27a screwed to the male screw portion 23a of the lock ring 23 is screwed on the outer periphery of the rear end portion of the adjusting sleeve 27.

Then, the adjusting sleeve 27 has the lock ring 23.
It is configured such that the protruding length of the driver bit 7 from the tip thereof, that is, the screw-in depth of the screw to be tightened can be adjusted by screwing the screw into or out of the screw.

The present embodiment is configured as described above, and the tightening operation will be described with reference to FIGS. 6A to 6G and 7A to G.

Now, according to the screwing depth of the screw Y to be tightened, the adjusting sleeve 27 is screwed or withdrawn with respect to the lock ring 23 to adjust and set the protruding length of the driver bit 7 from the tip thereof, and The tip of the screw 7 is aligned with the head of the screw Y to be tightened and the screw Y is brought into contact with the portion W to be tightened.

In this state, as shown in FIG. 2, the engaging balls 16 to 16
Is located in the deepest part of the central portion of each of the control groove portions 14 and 15, and further, in the movable clutch pawl portion 11
Is urged toward the main shaft 8 by the spring 17,
The engagement of both clutch claw portions 10 and 11 is disengaged. Therefore, even if the drive motor 3 is driven to rotate the motor shaft 4, only the main gear 6 is rotated and the rotation to the main shaft 8 and the driver bit 7 is not transmitted. (Fig. 6A
Therefore, when the main body of the electric screwdriver 1 is pressed against the portion W to be tightened together with the screw Y to be tightened (lateral direction), the main shaft 8 along with the driver bit 7 is axially directed toward the main gear 6 side. Moved and movable clutch pawl
11 is pushed toward the main gear 6 side against the elasticity of the spring 17 and meshed with the fixed clutch claw portion 10. (See FIG. 6B) Then, by driving the drive motor 3, the motor shaft 4
Rotation of the main gear 6 and the clutch means 9 in the meshed state
Is transmitted to the main shaft 8 via the drive shaft 7, the driver bit 7 starts rotating, and the tightening of the screw Y is started. Then, when the screw tightening load is applied to the main shaft 8 side with the start of tightening by the driver bit 7, the clutch means 9 is completely engaged, and the engaging ball 16 has both control groove portions 14 , 15 is moved and displaced from the deepest part of the substantially central portion along the inclined surfaces 14a, 15a to the open end side. As a result, the main shaft 8 is pushed out by the axial deviation amount a × 2 of the engaging ball 16 in the both control groove portions 14 and 15, and the space between the end surface of the main shaft 8 and the movable clutch pawl portion 11 is increased. A gap a'corresponding to the deviation amount ax2 is generated. (See FIG. 6C) As described above, the tightening operation for the screw Y is advanced while advancing the entire main body of the electric screwdriver 1. Then, when the tip of the adjusting sleeve 27 comes into contact with the portion W to be tightened, the forward movement of the main body of the electric screwdriver 1 to the portion W to be tightened is stopped. The tightening of Y continues and the screw Y advances axially. When the screw Y advances, the driver bit 7, the main shaft 8, and the movable clutch pawl 11 advance together with the screw Y due to the reaction force in the axial direction generated in the clutch portion, and the movable clutch pawl 11 and the fixed clutch pawl 10 move. The bite begins to dissociate. (See FIGS. 6D and 6E) In this state, the engagement ball 16 is still positioned on the open end side of the inclined surfaces 14a and 15a in the control groove portions 14 and 15, respectively.

Then, at the moment when the engagement between the movable clutch claw portion 11 and the fixed clutch claw portion 10 is disengaged, the rotation transmission to the main shaft 8 side is interrupted, so that the elasticity of the spring 17 acting on the movable clutch claw portion 11 causes The engagement ball 16 in each control groove portion 14, 15 is moved and displaced from the open end side along the inclined surfaces 14b, 15b to the deepest portion of the substantially central portion. That is, since the movable clutch claw portion 11 is pushed back toward the main shaft 8 side (moved to the left in the drawing) by the gap a'corresponding to the deviation amount ax2, the movable clutch claw portion 11 and the fixed clutch claw portion 10 are separated from each other. The disengaged state of meshing is completed, and the state is maintained. (Refer to FIGS. 6F and 6) Therefore, the rotation transmission from the main gear 6 to the main shaft 8 is completely cut off, and a mechanical noise or the like is generated for the disengagement operation of the engagement between the fixed clutch claw portion 10 and the movable clutch claw portion 11. Smooth and reliable.

After that, when the main body of the electric screwdriver 1 is separated from the part W to be tightened, as described above, the movable clutch pawl part is formed.
The main shaft 8 is pushed back to the initial state together with the movable clutch pawl portion 11 by the elastic force of the spring 17 acting on 11.

In this embodiment, the screw Y is tightened as described above. For example, if the screw Y does not reach the initially desired screw-in length, the screw Y is corrected to further tighten the screw. I need to stop
The additional tightening operation will be described below.

Now, after the screw tightening work is completed as described above, FIG.
When the head of the screw Y is protruded from the surface W to be tightened by a length t as shown in FIG.
Is screwed from the position initially set with respect to the lock ring 23 by the amount t to adjust the driver bit 7 to further protrude from the tip of the adjusting sleeve 27. In this state, the engaging ball 16 is in the above-described initial state in which the engaging ball 16 is located at the deepest portion of the control groove portions 14 and 15 substantially at the center. (See FIG. 7B) Then, the tip of the driver bit 7 is matched with the head of the screw Y to be tightened, and the main body of the electric screwdriver 1 is pressed against the portion W to be tightened. In the case, the movable clutch pawl portion 11 and the fixed clutch pawl portion due to the axial movement of the driver bit 7 and the main shaft 8
It is in a state where it is not meshed with 10. (See FIG. 7C) Then, when the operating lever 19 is pushed forward by using the pushing projection 19a to maintain the state, the operating lever 19
In accordance with the pushing of 19, the interlocking piece 20 is pushed in the same direction by the elasticity of the spring 22, and the tip 20a moves the main gear 6 together with the support shaft 2 to the main shaft 8 side via the thrust bearing 21. As a result, the engagement between the fixed clutch claw portion 10 and the movable clutch claw portion 11 is started. (See FIG. 7D) The amount by which the main gear 6 is pushed out by the interlocking piece 20 is limited to the above-mentioned deviation amount a × 2.

Then, the drive motor 3 is driven to start the rotation of the driver bit 7 in the same manner as described above to start the additional tightening of the screw Y, and the screw tightening load is applied to the main shaft 8 side and the engaging ball
16 is moved and displaced from the deepest part of the central portion of both control groove portions 14, 15 along the inclined surfaces 14a, 15a to the open end side thereof. As a result, the main shaft 8 tends to be pushed out by the axial displacement amount a × 2 of the engaging ball 16 in the control groove portions 14 and 15, but the spring 22 biased by the interlocking piece 20 causes Since the elastic force, that is, the spring pressure is set to be slightly weaker than the reaction force of the rotational torque applied to the clutch means 9, it is slightly pushed back against the elastic force of the spring 22 due to the reaction force of the rotational torque, thereby pushing it forward. The disengaged main gear 6 is pushed back to the initial position while maintaining the meshing of the fixed clutch claw portion 10 and the movable clutch claw portion 11, and the displacement between the end surface of the main shaft 8 and the movable clutch claw portion 11 is caused. A gap corresponding to the amount a × 2 is generated. (See FIG. 7E) In this state, the tip of the adjusting sleeve 27 is brought into contact with the portion W to be tightened and the forward movement of the main body of the electric screwdriver 1 with respect to the screw Y to be tightened is stopped. 8 and the movable clutch pawl 11 are advanced by the amount of meshing of the clutch means 9, and the corresponding tightening by the driver bit 7 is performed, after which the meshing of the movable clutch pawl 11 and the fixed clutch pawl 10 is disengaged. It (Refer to FIG. 7F) Then, at the moment when the engagement between the movable clutch claw portion 11 and the fixed clutch claw portion 10 is disengaged, the rotation transmission to the main shaft 8 side is cut off. 16 is located at the deepest part of the center of each control groove 14, 15. As a result, the disengaged state of the engagement between the movable clutch claw portion 11 and the fixed clutch claw portion 10 is completed, and the state is maintained. (Refer to FIG. 7G) Then, by the elastic force of the spring 22, the interlocking piece 20 which positively engages the clutch means 9 corresponding to the engagement / disengagement of the clutch means 9 is repeatedly performed by the elastic force of the spring 22. It is moved back and forth while being urged, and the operating lever 19
By releasing the pressing operation for, the additional tightening work is completed.

Next, another example of the present invention will be described with reference to FIGS. The present embodiment is a mode in which the configuration relating to the operation lever 19 and the interlocking piece 20 in the above-described embodiment is changed to directly move the support shaft 2 back and forth. In the following description, the same members as those described above will be denoted by the same reference numerals in the drawings, and the description thereof will be omitted.

As shown in the figure, an engaging recess 28 having a substantially V-shaped cross section is formed on the rear end surface of the support shaft 2, and a ball-shaped interlocking member 29 is fitted in the engaging recess 28.

The interlocking piece 30 bent into a substantially crank shape is the housing 1a.
A bent portion 30a is tiltably supported on a rear upper portion of the support shaft 2 through a support pin 31, and a piece 30b extending obliquely downward from the bent portion 30a is brought into contact with the interlocking member 29. Further, the other piece 30c that extends from the bent portion 30a in a substantially horizontal shape and has the end portion bent upward in a hook shape is the housing 1a.
It is positioned so as to be exposed to the outer surface of the housing 1a so as to face the space 18 formed in the upper surface of the rear end portion of the housing 1a.
A spring 32 is mounted between the piece 30b of 30 and the wall surface in the housing 1a. Further, the interlocking piece 30 is always located in the upper part of the void 18 formed on the upper surface of the rear end portion of the housing 1a while maintaining the contact state with the interlocking member 29 by the elasticity of the spring 32 at all times. The other piece 30c is pushed to almost the bottom surface of the space 18 to be tilted against the elasticity of the spring 32 by using the support pin 31 as a fulcrum, and the one piece 30b and the interlocking member 29 are moved. The support shaft 2 is moved to the front side, that is, to the main shaft 8 side, and the fixed clutch claw 10 is engaged with the movable clutch claw 11. The other piece 30c of the interlocking piece 30 constitutes a pushing portion at the time of tilting operation, and the rest of the construction is the same as that of the above-mentioned embodiment.

Therefore, in this embodiment, when the interlocking piece 30 is pushed to almost the bottom surface of the void 18 by using the other piece 30c during the additional tightening operation, the interlocking piece 30 springs with the support pin 31 as a fulcrum. Tilt against the elasticity of 32, piece 30
The supporting shaft 2 is moved forward, that is, toward the main shaft 8 side through the b and the interlocking member 29, and the fixed clutch claw portion 10 is engaged with the movable clutch claw portion 11. The same operation as in the above-described embodiment is performed. It is to enjoy the effect.

Although the present embodiment has been described with respect to an electric screwdriver, it can be easily applied to a pneumatic screwdriver.

(Effect) As described above, according to the present invention, the control groove portion between the movable clutch pawl portion and the main shaft in the clutch means and the engaging means engaging with the control groove portion can prevent metallic noise and the like generated when transmission of rotation of the clutch means is interrupted. While reducing noise as much as possible,
The engagement / disengagement operation of the clutch means is positively controlled by means different from the engagement / disengagement operation of the clutch means by the control groove portion and the engagement means engaged with the control groove portion, that is, the operation means operated from outside the main body of the electric screwdriver. Therefore, the additional tightening operation can be easily performed even when the tightening length initially desired is not tightened.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a front sectional view including a partial breakage, FIG. 2 is a plan view of a main part, FIG. 3 is an exploded perspective view of the same part, and FIG. An enlarged plan view showing the control groove portion in an expanded manner, FIG. 5 is an enlarged sectional view taken along line VV of FIG. 1, and FIG. 6A.
7A to 7G are explanatory views showing an operating state, FIGS. 7A to 7G are explanatory views showing an operating state at the time of tightening, FIG. 8 is a front sectional view including a partial breakage showing another embodiment, and FIG. Similarly, FIG. 10 is an exploded perspective view of the main part, and FIG. 10 is a front sectional view similarly showing the operating state of the interlocking piece. 1 …… Electric screwdriver 1a …… Housing 6 …… Main gear 7 …… Driver bit 8 …… Main shaft 9 …… Clutch means 10 …… Fixed clutch pawl 11 …… Moveable clutch pawl 14,15 …… Control groove 14a, 15a …… Sloping surface 16 …… Engaging ball 17 …… Spring 18 …… Vacancy 19 …… Operating lever 20,30 …… Interlocking piece 27 …… Adjusting sleeve

Claims (1)

[Claims] 1. An adjusting sleeve mounted at a front end portion of a housing so as to adjust a position in an axial direction, and a main body rotatably and axially movably supported in the housing and rotated by a driving device. A spindle provided with a gear, and a spindle provided with a driver bit located coaxially with the spindle in the housing, rotatably and axially movably supported, and located in the adjusting sleeve. A fixed clutch portion provided between the main gear and the main shaft and provided on the main gear side, and provided on the main shaft side so as to cooperate with the axial movement of the main shaft, and always by a spring. In an electric screwdriver provided with a clutch means including a movable clutch portion biased in a direction away from a fixed clutch portion, a phase of the movable clutch portion of the clutch means and the main shaft is provided. Grooves are formed in the facing portions, and engaging means for interposing rotation between the movable clutch portion and the main shaft are inserted in the groove portions, and at least one groove portion in the groove portion is the clutch. The engaging means is provided with a control groove portion having a displacement amount for axially displacing and moving in response to engagement and disengagement movement of the means, and the support shaft side is connected to the support shaft side and the support shaft side is connected to the support shaft side. An operating means is provided which has an operating portion that presses the main shaft side and can be operated from the outer surface of the housing, and applies an urging force that pushes the supporting shaft side of the operating means to the main shaft side to the clutch means. An electric screwdriver characterized by being set weaker than the reaction force of the rotating torque.