JPH0696208B2 - Screw tightener - Google Patents

Description

TECHNICAL FIELD The present invention has been made in such a manner that a screw tightening machine using a push-start type electric screwdriver mechanically switches an electric screwdriver so as to interlock with a moving operation of the electric screwdriver. It relates to the device.

2. Description of the Related Art In recent years, a screw tightening drive source of a screw tightener has changed from an air screwdriver to an electric screwdriver, and in particular, a push start type with high tightening torque accuracy is widely used.

An example of the above-described conventional screw tightener will be described below with reference to the drawings.

FIG. 4 shows a side view with a partial cross section of the main part of a conventional screw tightener. In FIG. 4, reference numeral 1 denotes a push-start type electric driver, which has a structure in which the driving side and the driven side are mechanically engaged with each other when the output shaft 2 is pushed, and at the same time, electrically connected by a switch or the like. Reference numeral 3 is a block that supports the electric screwdriver 1 and has a two-part structure, and an elastic synthetic resin 3a is attached to the electric screwdriver grip portion. The block 3 is fixed to a pipe 5 fixed to a slide holder 4. The slide holder 4 is configured to slide on a slide shaft 8 by a cylinder 7 attached to a fixed plate 6. Reference numeral 9 is an intermediate shaft fixed to the output shaft 2 by a pin 10, and the other end is connected to a bit 13 via a universal joint 12 fixed by a pin 11. Reference numeral 14 is a bit 13 guide pipe.

The operation of the screw tightener configured as described above will be described below.

First, the cylinder 7 starts to move the slide holder 4 in the direction of arrow a, and when the tip of the bit 13 engages with a screw (not shown) and moves in the direction of arrow b, the electric screwdriver 1 is a push start type. When the output shaft 2 moves, the mechanical power is transmitted, and when the electrical contact is closed, the motor rotates and the bit 13 rotates. When the predetermined screw tightening is completed, the slide holder 4 returns in the direction of arrow c, the bit 13 also returns in the direction of arrow d, and the mechanical connection in the electric screwdriver 1 is released. When the bit 13 is returned in the direction of arrow d, the spring in the electric screwdriver 1 is operating.

FIGS. 5 (A) and 5 (B) show a state in which the screw 16 flowing on the inclined chute 15 enters the catcher 17 and is then pushed out by the bit 13, and 18 is the catcher.
It is the pin that becomes the center of rotation of 17.

Problems to be Solved by the Invention However, with the configuration as described above, the electric screwdriver 1
Must be pushed in the direction of arrow b to rotate, so bit 13
Has a problem that it does not engage with the cross hole of the screw 16 and repels the screw 16 in the direction of arrow e as shown in FIG. 5 (B).

There is also a method in which the bit is pressed against an electric screwdriver in advance by a separately driven cylinder or the like so as to be mechanically coupled, but there is a problem that the device becomes large and the cost is high in terms of mechanism and electric control.

In view of the above problems, the present invention provides a spring around the output shaft and the intermediate shaft of a push-start type electric screwdriver that does not work at a fixed position of the electric screwdriver and that urges the bit toward the electric screwdriver side when the movement starts. (EN) Provided is a screw tightening machine which is provided and rotates a bit until the bit hits the screw, thereby smoothly engaging the bit and the screw.

Means for Solving the Problems In order to solve the above problems, a screw tightening machine of the present invention includes a push-start type electric screwdriver, a block for holding the electric screwdriver, a drive source for moving the block, and a fixed drive source. A frame, a bit connected to the electric screwdriver output portion, a spring for urging the bit toward the electric screwdriver, and a means for temporarily releasing the pressing force of the spring,
In the return limit of the electric driver, the spring urges the bit toward the electric driver side, and the spring again urges the bit toward the electric driver as the drive source moves the electric driver. It has a configuration.

Operation According to the present invention, with the above-described configuration, the bit is rotated when the electric screwdriver starts moving, so that the cross part of the tip of the bit smoothly meshes with the screw head cross hole in the catcher. When it returns to the position, it releases the push pressure of the bit and resets the mechanism inside the electric screwdriver.

Example Hereinafter, a screw tightener of the present invention will be described with reference to the drawings.

FIG. 1 shows a screw tightener in an embodiment of the present invention. In FIG. 1, 19 is a push-start type electric screwdriver, which mechanically meshes the drive side (motor side) and the driven side (bit side) by pressing the output shaft 20, and at the same time electrically connects them with a switch or the like. Structure. twenty one
An elastic synthetic resin 21a is attached to the electric driver grip portion. The block 21 is fixed to a pipe 23 fixed to a slide holder 22. The slide holder 22 is attached to the fixed plate 24 by the cylinder 25,
It is configured to slide on the slide shaft 26. 27 is an intermediate shaft fixed to the output shaft 20 by a pin 28, and the other end is a pin 29.
Through the universal joint 30 fixed with the pin 31
Bits 32 fixed by are combined. 33 is a bit 32 guide pipe. On the other hand, a spring bearing 34 is slidably fitted into the inner diameter surface of the pipe 23, and a plate 35 protruding from the opening 23a of the pipe 23 is fixed to one end of the inner diameter projection 34a of the spring bearing 34 and an intermediate shaft. Thrust bearing 37 is fixed between retaining rings 36 in 27, and the other end of inner diameter protrusion 34a
Abut on the retaining ring 38a fitted in the pipe inner diameter,
And a start spring 40 between the spring seat 39 and the spring seat 39 having a constant clearance. 38b has another retaining ring that holds the bearing 41. The intermediate shaft 27 is slidable in the axial direction with respect to the bearing 41. Further, the trap lever 42 is fixed to the fixed plate 24, and the protruding portion 42a of the trap lever 42 comes into contact with the plate 35 when the electric screwdriver 19 returns to the fixed position.

FIG. 2 shows a state in which the top lever 42 contacts the plate 35 and the electric screwdriver 19 returns.

FIG. 3 is a cross section taken along the line XX of FIG. 2, and 43 is a cover.

Regarding the screw tightening machine configured as described above, the first
The operation will be described with reference to FIGS. 2, 2 and 3.

First, FIG. 2 is a view in which the electric screwdriver 19 is in a fixed position and the apparatus is in a steady state. As shown in FIG. 1, when the plate 35 which moves by the stroke S is separated from the trap lever 42, Spring support by the elastic force of spring 40
34 is pushed upward, and the intermediate shaft 27 moves in the arrow A direction via the thrust bearing 37 and the retaining ring 36. Since the spring 40 is much stronger than the reset spring (not shown) inside the electric screwdriver 19, the output shaft 20 is pushed to the electric screwdriver 19 side, and the mechanism such as the internal clutch is in the torque transmission state. Electric driver 19 before and after this operation
If you close the switch that supplies power to the motor, the motor (not shown) inside the electric screwdriver 19 will rotate and the center deviation between the output shaft 20 and the bit 32 will be absorbed through the output shaft 20, the intermediate shaft 27 and the universal joint 30. Bit 32 rotates to do so.
When the tip of the bit 32 touches the screw head (not shown) as the electric screwdriver 19 descends, the rotating bit 32 comes into contact with the stationary screw.
The cross part of the tip of 32 meshes smoothly, and the screw does not fly at the tip of bit 32. This is a bit that pre-adsorbs the screw
The same applies when picking up at 32 or when directly picking up the screw in the catcher.

Next, when the predetermined screw tightening is completed, the electric screwdriver 19 is pulled up to the original position by the cylinder 25. However, as shown in FIG. 2, at the upper limit of the electric screwdriver 19, the plate 35 fixed to the spring bearing 34 is fixed. It abuts the lower end of the trap lever 34 and compresses the start spring 40. Therefore, the intermediate shaft 27
The elastic force of the start spring 40 does not act on the output shaft 20 and the reset spring (not shown) inside the electric screwdriver 19
Is returned in the direction of arrow B, and the mechanism such as the clutch inside the electric screwdriver 19 that has been operated for tightening the screw is restored to the reset state.

As described above, according to this embodiment, by providing the spring for urging the bit toward the electric screwdriver and the means for temporarily releasing the pressing force of the spring, it is possible to prevent the bit from rotating with the screw. Because of the mating, it is possible to stably connect the bit cross portion to the screw cross hole.

In the embodiment, the screw tightening drive source is the push start type electric screwdriver 19, but a push start type pneumatic tool may be used. Although the cylinder 25 is used as the drive source for moving the electric screwdriver 19, it may be driven by a motor or manually.

As described above, the present invention provides a push-start type screw tightening tool by providing a spring for urging the bit of the screw tightening tool to the screw tightening tool example, and a means for temporarily releasing the pressing force of the spring. In a screw tightening machine using a screw tightening drive as a drive source, it is possible to eliminate the trouble caused by the bad engagement between the bit and the screw, and a device for turning the bit before screwing is attached to the bit spindle part at a compact and low cost. It can be applied to screw tightening machines in general and greatly enhances its reliability.

[Brief description of drawings]

1 is a partial side view of a partial cross section of a screw tightener according to an embodiment of the present invention, FIG. 2 is a front view of a partial cross section of FIG. 1,
Fig. 3 is a cross-sectional view taken along the line X-X in Fig. 2, Fig. 4 is a side view of a partial cross section of a conventional screw tightener, and Figs. 5A and 5B are screws at the tip of the screw tightener. It is a partial side view of a partial cross section when a bit contacts the head. 19 …… electric screwdriver, 20 …… output shaft, 21 …… block, 22 …… slide holder, 23 …… pipe, 24 …… fixed plate, 25 …… cylinder, 30 …… universal joint, 32 …… bit, 34 …… Spring holder, 35 …… Plate, 40 …… Spring, 42 …… Trap lever.

Claims (2)

[Claims] 1. A push-start type screw tightening tool, a block for holding the screw tightening tool, and a drive source for moving the block.
A frame for fixing the drive source, a bit connected to the output part of the screw tightening tool, a spring for urging the bit toward the screw tightening tool, and a means for temporarily releasing the pressing force of the spring, At the return end of the screw tightening tool, the spring releases the bias of the bit toward the screw tightening tool, and the spring again moves the bit to the screw tightening tool as the drive source advances the movement of the screw tightening tool. A screw tightener characterized by urging. 2. The screw tightener according to claim 1, wherein an output portion of the screw tightening tool and the bit are connected by a universal joint.