JP2592354Y2 - Screw supply mechanism of screwdriver - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a screw connecting body in which a number of screws are supported in parallel in a row on an elastic connecting band (for example, made of synthetic resin), and is provided in front of a screw driver bit rotated by a motor. The present invention relates to a screw supply mechanism of a screw tightening machine that sequentially supplies a screw to a workpiece by pushing a screw from a connection band by a driver bit and screwing the screw into a work.

[0002]

2. Description of the Related Art A plurality of screws are connected to a connecting band made of elastic synthetic resin by inserting a shaft portion of the screw into a supporting band, and the connecting screw is rotated forward by a motor on the shaft center of a driver bit. Screwdriver that intermittently supplies the screw, engages the screw with the driver bit by the forward movement of the driver bit, causes the screw to escape from the connection band, and screws into the work placed in front of the driver bit. Are known.

As shown in FIG. 4, the screw supply mechanism of the conventional screw tightener is formed on a screw supply path 21 formed so as to intersect with the axis of a driver bit 20 at both side edges of a screw connection band. And a drive mechanism 23 for intermittently rotating the feed ratchet 22 for engaging the engaging concave portion and moving the screw connection band along the supply path 21. The drive mechanism 23 is connected to the feed pawl 22
And a piston / cylinder 26 for reciprocating the operating lever 25 which is arranged to be able to engage with a rib 24 formed on a side surface of the operating lever 25. By the operation of the piston, the feed ratchet 22 is rotated by a predetermined angle via the operation lever 25 by the operation of the piston to move the screw connection band by a predetermined pitch to supply the leading screw N on the axis of the driver bit 20. is there.

[0004]

According to the above-mentioned conventional mechanism, the sprocket is rotated by a predetermined angle or more due to the inertia force caused by the rotation of the sprocket and the movement of the screw connection band. A phenomenon of further moving forward occurs (see FIG. 4B). In particular, if the supply speed of the connecting band is increased in order to increase the efficiency of the screw tightening operation, the above-described phenomenon is likely to occur, so that there is a problem that the operating speed of the tool cannot be increased. Due to this phenomenon, the driver bit 20 cannot be engaged with the groove of the head of the screw, the torque cannot be transmitted to the screw N, and the screw cannot be screwed in, or the screw N cannot be held at the tip of the driver bit 20. Troubles the screw tightening work. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a connecting screw supply mechanism that does not cause excessive feeding of the screw connecting band even when the feeding speed of the screw connecting band is increased.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a driver bit which moves in the axial direction while rotating a screw on a screw connection band which is connected by inserting and supporting a plurality of screw shafts. In a screw tightening machine that is continuously supplied on the axis, engages the driver bit and the screw, moves in the screw axis direction, separates from the connecting band, and screws the work to the work, A supply guide for a screw connection band disposed orthogonal to the axis of the driver bit, and a claw that is rotatably disposed on the supply guide and that engages with a part of the screw connection band on an outer peripheral edge thereof. A feed ratchet formed, an operating lever that engages a radial rib formed on the outer surface of the feed ratchet to rotate the feed ratchet by a predetermined angle, and rotates the operating lever to reciprocate the operation lever Freely The feed piston, and a feed cylinder slidably housing the feed piston. When the feed piston is operated to the bottom dead center position where the feed ratchet is rotationally driven, the feed piston is moved out of the feed ratchet. A stop piece arranged near the periphery is formed in a part of a portion operated by the feed piston.

[0006]

[Operation and Effect of the Invention] A stopper formed on a part of a piston rod of a piston for rotationally driving a feed ratchet is engaged with a projection formed on an outer peripheral surface of the feed ratchet while the piston supplies a screw. Thus, excessive rotation of the feed ratchet in the supply direction is prevented. As a result, excessive rotation of the feed ratchet and excessive movement of the screw connection band in the supply direction due to inertia and the like are prevented, and the leading screw is reliably stopped at the axial center position of the driver bit. Therefore, the driver bit and the groove of the screw head are securely engaged, and the screwing can be reliably performed. Further, after the screw is detached from the connecting band, it can be securely held at the tip of the driver bit.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to FIGS. FIG. 1 shows a partial structure of a screw tightening machine in which a screw feeding mechanism of the present invention is implemented. The screw tightening machine 1 has a hexagonal cross-section rotating drive shaft 2 driven by a motor (not shown). A driver bit 4 supported at the tip of a connecting cylinder 3 fitted slidably in the axial direction on the outer periphery of the rotary drive shaft 2; and a connecting portion at a lower end portion for moving the driver bit 4 in the axial direction. An annular piston 5 rotatably and axially connected to the cylinder 3,
An annular cylinder 6 which slidably accommodates the annular piston 5
Further, a sleeve 7 which is integrally moved with the driver bit at the beginning of the movement stroke in accordance with the axial movement of the driver bit 4 is provided on the outer periphery of the driver bit 4 at the upper end thereof. 5 is supported and disposed at the lower end of the operating sleeve 8 engaged with the operating sleeve 5.

Further, the screwdriver 1 has a driver bit 4
A supply guide 9 for supplying a screw connection band is formed in front of the screw guide 4 at right angles to the axis of the driver bit 4, and the supply guide 9 is formed on both sides of the screw connection band on the front side in the screw supply direction. A pair of feed pawls 11 each having a pawl 10 formed on the outer periphery for engaging with the notch is rotatably supported and disposed on a shaft 11a. As shown in FIG. 2, a plurality of ribs 12, 12 extending substantially radially
A feed cylinder 13 as a drive mechanism of the feed ratchet 11, a feed piston 14 slidably disposed in the feed cylinder 13, and a feed piston 14
An operating lever 15 rotatably supported by a support shaft 18 is disposed at the tip of the piston rod. Each time the feed piston 14 is reciprocated, a roller 16 provided at the tip of an operating lever 15 engages with the rib 12 to intermittently drive the feed ratchet 11 by a predetermined rotation angle, thereby forming a screw connection band. Is moved along the supply guide 9 so that the leading screw N is supplied on the axis of the driver bit 4.

The operating lever 15 is rotatably supported by a support block 17 fixed to the end of the piston rod, and the feed pawl wheel whose reverse rotation is prevented by a reverse rotation preventing mechanism (not shown) during the return process of the feed piston 14. The shaft 11 can be rotated in the direction of the hour hand around the support shaft 18 so as to be able to return to the upper side over the rib 12 on the near side in the supply rotation direction 11. Operating lever 1
The engagement of the upper end surface 15 ′ of the fifth member 5 with the support block 17 limits the swinging of the operating lever 15 in the counterclockwise direction. Further, the lower end portion of the support block 17 is disposed at a position close to the outer peripheral edge of the feed pawl 11 so that the feed piston 14 can be engaged with the pawl 10 of the feed pawl 11 in a state where the feed piston 14 is operated in the supply direction. A piece 19 is formed.

The outline of the operation of the screw tightening machine is as follows. In the initial state of the screw tightening machine 1, the annular piston 5 is at the upper end position in FIG. 1, and the driver bit 4 and the sleeve 7 are at positions retracted upward from the screw supply guide 9. In this state, when the operator operates a starting mechanism (not shown), the motor drives the rotary drive shaft 2 and the connecting cylinder 3 to rotate and drive the driver bit 4, and the annular piston 5 advances in the axial direction. To advance the sleeve 7 and the driver bit 4 forward in the axial direction.
And the groove formed in the head of the screw N are engaged, and the screw N is moved in the axial direction while rotating to separate from the screw connection band and simultaneously screw into the work. When the operator releases the activation mechanism after the screwing operation of the screw N is completed,
When the rotation of the motor is stopped, the rotation of the rotary drive shaft 2 and the connecting cylinder 3 is stopped, and at the same time, the annular piston 5 also returns to the upper initial position.

Hereinafter, the operation of the screw supply mechanism of the screw tightening machine according to the present invention will be described. As described above, after the screwing is completed and the driver bit 4 is lifted and returned, compressed air is supplied into the feed cylinder 13 to feed the feed piston 1.
4 is actuated towards bottom dead center. Piston rod 14 '
The base end of the operating lever 15 supported by a support block 17 fixedly formed at the distal end of the moving lever 15 is moved downward, and the roller 16 provided at the distal end of the operating lever 15 is engaged with the rib 12 of the feed ratchet 11. Then, it is pressed and rotated. The rotation of the feed ratchet wheel 11 pushes the screw connection band engaged with the pawl 10 to advance the leading screw N on the connection band below the driver bit 4. When the feed piston 14 reaches the bottom dead center, the roller 16 of the operating lever 15 rotates the rib 12 by a predetermined rotation angle and inserts the leading screw N into the driver bit 4.
On the axis of.

In a state where the feed piston 14 is operated to the bottom dead center position, the stopper 19 formed at the lower end of the support block 17 fixed to the piston rod 14 ′ approaches the outer peripheral edge of the feed ratchet 11. Position and feed ratchet 1
1 is arranged on the near side in the rotation direction of the claw 10 protrudingly formed on the outer periphery. Due to the inertia of the feed pawl 11 itself or the inertia of the screw connecting band, the rotational force of the feed pawl 11 to rotate further in the direction of supplying the screw connecting band is related to the pawl of the feed pawl 11 and the stop piece 19. Feeding claw wheel 1 by joining
1 is prevented from rotating excessively, and the leading screw N is accurately supplied on the axis of the driver bit 4.

After the supply of the screw connection band is completed, the feed piston 14 is operated to return upward, and accordingly, the operating lever 15 is also moved upward. In this return stroke, the operation lever 15 is rotated about the shaft 18 so as to be able to get over the rib 12 located on the near side in the rotation direction and return. At this time, the feed pawl 11 is prevented from rotating in the direction opposite to the supply direction by a reverse rotation preventing mechanism (not shown). The operating lever having passed over the rib 12 is returned and rotated by the action of a spring (not shown), and the upper end surface 15 'of the operating lever 15 comes into contact with the support block 17 and is located at the initial position.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a screw tightening machine having a screw supply mechanism according to the present invention.

FIG. 2 is a sectional view showing an initial state of a screw supply mechanism of the screw tightening machine of FIG. 1;

FIG. 3 is a cross-sectional view showing a state at the end of a supply operation of a screw supply mechanism of the screw tightening machine of FIG. 1;

4A and 4B are cross-sectional views illustrating an operation state of a conventional screw supply mechanism, in which FIG. 4A illustrates a state immediately after the supply operation is completed, and FIG. 4B illustrates a state in which excessive screw feeding occurs due to inertia.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 screw tightening machine 2 rotation drive shaft 3 connecting cylinder 4 driver bit 5 annular piston 6 annular cylinder 7 sleeve 8 operating sleeve 9 supply guide 10 pawl 11 feed pawl wheel 12 rib 13 feed cylinder 14 feed piston 15 operating lever 16 roller 17 support block 18 Support shaft 19 Stopper N screw

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A 4-70431 (JP, U) JP-A 5-16072 (JP, U) (58) Fields surveyed (Int.Cl. ⁶ , DB name) B23P 19/06 B25B 23/04

Claims (1)

(57) [Scope of request for utility model registration] 1. A screwdriver comprising: a plurality of screw shafts which are inserted and supported and connected to each other to continuously supply a screw on a screw connecting band on an axis of a driver bit moving in an axial direction while rotating the screw; And a screw tightening machine which is disengaged from the connection band and screwed into the work by moving the screw in the direction of the screw axis, and disposed in front of the driver bit so as to be orthogonal to the axis of the driver bit. A feed guide for a connecting band, a feed ratchet rotatably disposed on the feed guide and having a protruding claw formed on an outer peripheral edge thereof for engaging a part of the screw connecting band, and an outer surface of the feed ratchet An actuating lever for engaging the radial ribs formed on the shaft to rotate the feed ratchet by a predetermined angle, a feed piston rotatably supporting the actuating lever for reciprocating the actuating lever, and sliding the feed piston Self Has the accommodated the feed cylinder,
When the feed piston is operated to the bottom dead center position where the feed ratchet is rotationally driven, the feed piston is operated by the feed piston.
Of the stop part formed on a part of the part
A screw feed mechanism, wherein the screw feed mechanism engages with a claw .