JP3002748B2 - screwdriver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a screwdriver for attaching and detaching a screw screw or the like with high torque.

[Related Art] A screwdriver that attaches and removes a screw screw may rust the screw screw or break a groove for fitting a bit of the screwdriver when the screw screw that is attached by being strongly tightened is removed.

This phenomenon is caused by the fact that when the bit comes out of the groove regardless of whether the groove is a + type or a − type, the edge of the groove is damaged to reduce the fitting margin, thereby reducing the coupling force by the fitting of the bit and the groove. The screw screw cannot be tightened or loosened due to the decrease.

In particular, such a problem occurs when it is attached with being strongly tightened, or when it is attached and removed in a rusted state.

Conventionally, when a screw screw is tightened and attached, a clutch is interposed so that the bit does not forcibly turn the screw screw, or the torque of the electric motor of the power source is set to the necessary minimum. Was by the way.

However, in such a method, a high torque is required to remove the rusted screw, so that it is necessary to use a high-torque screwdriver in some cases, which is in some cases meaningless.

Furthermore, when attaching a self-tapping screw to a soft member such as wood, if the screw is pushed with a bit, the screw may fall down and become unable to be attached.

In such a case, a self-tapping screw has to be supported so as not to fall down by hand or hammered a little with a hammer so as not to fall down and then screwed with a bit to rely on a troublesome method.

[Problems to be Solved by the Invention] The present invention has been made in view of such circumstances, and breaks a groove formed in a screw head that requires high torque such as rusting into a screw head. It is an object of the present invention to provide a screw driver which can be easily attached and detached without being screwed down, and which can be screwed so that a falling self-tapping screw does not fall down.

[Means for Solving the Problems] A screwdriver according to the present invention is a screwdriver that rotates a bit forward and backward at a low speed, and includes a motor 4 that is a driving unit of the screw driver and a rotary shaft that is a rotating shaft of the motor 4. Equipped with one shaft 1 and a lever 5 at one end,
A second shaft 2 movable in the axial direction, a first gear 2a loosely fitted on the second shaft 2, and a second gear 2b loosely fitted on the second shaft 2 and provided with a clutch mechanism; And the third gear
2c, an output shaft, a third shaft 3 having a bit holder attached to one end, and the second gear 2b tightly fitted to the third shaft 3
A fourth gear 3a meshing with the third shaft 3; a fifth gear 3b loosely fitted to the third shaft 3 and having a ratchet formed on one side; and a fifth gear 3b closely fitted to the third shaft 3 A sixth gear 3c having a ratchet formed on the side surface of the fourth gear 3a;
And a spring 8 disposed between the second gear 5b and the fifth gear 3b, the spring 8 pressing the fifth gear 3b against the sixth gear 3c by a spring pressure to form a ratchet gear, and operating the lever 5 Thus, a striking mode and a rotation mode, which can be converted by moving the second shaft 2 in the axial direction, are constituted by the striking mode, the second shaft 2 and the first gear 2a.
And the third gear 2c are connected, the second gear 2b is stopped, the fifth gear 3b is rotated by rotating the third gear 2c, and the ratchet gear is operated. The second shaft 2 and the first gear
2a and the second gear 2b are connected, the third gear 2c is stopped, and the second gear 2b is rotated to rotate the fourth gear 3a and rotate the third shaft 3. This solves the problem.

[Operation] When a screw screw requiring a high torque is removed due to rusting or the like, the striking mechanism is operated to apply vibration to the screw screw by an impact in the axial direction.

Such vibration can easily release the binding force due to rust to loosen the rusted screw screw.

Then, if the screw falls down before screwing, such as a self-tapping screw, and cannot work, it can be hit and driven, so that the screwing can be performed without falling down.

 Therefore, this type of work can be done with one hand.

Also, when the screw is strongly tightened and attached to the wood, it can be tightened more strongly by operating the striking mechanism at the point of completion of the tightening and hitting the screw in the axial direction. Can be prevented from protruding.

[Example] The present invention will be described based on an example shown in the drawings. FIG. 1 is a longitudinal sectional view of a screwdriver according to an example of the present invention.

In FIG. 1, the screw driver is provided with three first to third shafts 1, 2, and 3 in parallel. The first shaft 1 is an output shaft of the electric motor 4, and the second shaft 2 Is an operation shaft configured to be movable in the axial direction by the lever 5.

The third shaft 3 is a shaft provided with a chuck 6 to which a bit (not shown) is attached.

Further, the whole constituted by the first to third shafts 1, 2, 3 and the like is housed in a case (not shown) to constitute a screw driver which is a kind of electric tool.

The first shaft 1 is configured such that forward rotation and reverse rotation can be easily performed by a motor 4 by a switch (not shown).

The second shaft 2 has three first to third shaft gears 2a,
2b and 2c are provided, and clutches 2x (or fixed keys), 2y and 2z are provided for the second shaft 2, respectively.

Further, the third shaft 3 includes fourth to sixth gears 3a, 3b, 3c, and the fourth gear 3a is always connected to the third shaft 3 and meshes with the second gear 2b.

The fifth gear 3b is configured to freely rotate with respect to the third shaft 3. The fifth gear 3b meshes with the third gear 2c and has a ratchet gear 7 serving as a striking mechanism with the sixth gear 3c. Make up.

A lever 5a indicated by a dotted line in the drawing indicates a position when the lever 5 is moved by being pulled in the axial direction.

Further, a fifth gear 3b constituting the ratchet gear 7
Is configured to be constantly pressed toward the chuck 6 by the spring 8 to strike the shaft 3 in the axial direction.

Therefore, the shaft 3 can move in the axial direction.

In such a configuration, in the screw driver, when the electric motor 4 is started, the first gear 2a rotates.

Therefore, when the lever 5 is at the position shown by the solid line in the figure, the second shaft 2 and the first
The gear 2a and the third gear 2c rotate in connection.

Therefore, the fifth gear 3b is rotated by the third gear 2c, and the ratchet gear 7 is operated.

When the ratchet gear 7 operates, the third shaft 3 vibrates, and the chuck 6 vibrates in the axial direction. If a bit is attached to the chuck 6, the screw can be hit in the axial direction by the bit. (Striking mode) When the lever 5 moves to the position indicated by the dotted line in the figure, the second shaft 2 and the clutch 2z are disengaged, the third gear 2c is stopped, and the clutch 2y is connected to connect the second gear. 2b rotates.

Therefore, the fourth gear 3a of the third shaft 3 rotates to rotate the third shaft 3 and rotate the chuck 6.

Since the third gear 2c does not rotate, the ratchet gear 7 does not operate, and the chuck 6 rotates only without vibrating in the axial direction. (Rotation mode) When a screw driver is mounted in this way, the screw driver is applied to a portion where the screw screw is to be mounted, pressed with a bit, and further, when the electric motor 4 is started, the bit is hit in the axial direction and the tip of the screw screw is driven. Is driven into the mounting part to some extent.

In this state, when the lever 5a is pulled to a position (rotation mode) as shown by a dotted line in the figure, the vibration of the chuck 6 stops and the chuck 6 changes to rotation.

Therefore, the screw screw will bite into the mounting location.

Also, if the screw screw installed in this way cannot be easily removed due to rust, etc., hit the bit first in the axial direction and then reversely rotate the bit, just as when screw screw was installed. Thereby, the rusted screw can be easily loosened.

Such a screw driver can be easily screwed into a hard member such as a sizing board of a building material, for example, by first hitting the screw screw a little and driving it in, so that the work does not fail.

Therefore, there is no need to perform two operations, such as hitting once with a conventional hammer and then rotating with a driver, and the function as a power tool can be greatly improved.

[Effects of the Invention] According to the present invention, the screw can be screwed and then screwed together, so that the groove into which the bit is fitted for mounting on a hard object or removing it when it is rusted is damaged. Work can be carried out without any problem, so that the effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a screw driver according to one embodiment of the present invention. 1, 2, 3 ... axis, 4 ... electric motor, 5 ... lever, 7 ...
... Ratchet gear.

──────────────────────────────────────────────────続 き Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B25B 21/00 B25B 21/02 B23B 45/00 B23B 45/02

Claims (1)

(57) [Claims] 1. A screw driver for rotating a bit forward and backward at a low speed, comprising: a motor 4 as a driving unit of the screw driver; a first shaft 1 as a rotation shaft of the motor 4; and a lever 5 at one end. Second axis 2 movable in the axial direction
A first gear 2a loosely fitted to the second shaft 2; a second gear 2b and a third gear 2c loosely fitted to the second shaft 2 and provided with a clutch mechanism; Yes, 3rd axis 3 with bit holder attached at one end
A fourth gear 3a closely fitted to the third shaft 3 and meshing with the second gear 2b; a fifth gear 3b loosely fitted to the third shaft 3 and having a ratchet on one side surface; A sixth gear 3c closely fitted to the third shaft 3 and having a ratchet formed on a side surface on the fifth gear 3b side; and a sixth gear 3c disposed between the fourth gear 5a and the fifth gear 3b. A spring 8 that presses the fifth gear 3b against the sixth gear 3c to form a ratchet gear, and operates the lever 5 to move the second shaft 2 in the axial direction. The impact mode and the rotation mode that can be converted are configured. In the impact mode, the second shaft 2 is connected to the first gear 2a and the third gear 2c, the second gear 2b is stopped, and the third gear 2c is rotated. The fifth gear 3b
Is rotated to operate the ratchet gear. In the rotation mode, the second shaft 2 is connected to the first gear 2a and the second gear 2b, the third gear 2c is stopped, and the second gear 2b By rotating the fourth gear 3a
A screw driver, characterized in that the third shaft 3 rotates.