JPS632634A - Thread fastening machine - Google Patents

Abstract

PURPOSE:To make an engagement failure between a bit and a thread preventable from occurring, by installing a spring, energizing a thread fastening till bit to the thread fastening tool side, and a device opening the spring's pressing force temporarily. CONSTITUTION:When a plate 35 is separated from a trap lever 42, a spring bearing 34 is pushed upward by resilience of a spring, and a countershaft 27 is moved via a bearing 27 and a retaining ring 36. Since a spring 40 is stronger than a setting spring existing in the inner part of a motor-operated driver 19, an output shaft 20 is pressed to the side of this motor-operated driver 19 whereby a mechanism of a clutch or the like inside comes into a torque transmitted state. If the specified thread fastening is over, the motor-operated driver 19 is pulled up to its original position by a cylinder 25. At an up limit of the motor-operated driver 19, the plate 35 clamped to the spring bearing 34 comes into contact with a lower end of the trap lever 42, compressing the start spring 40. Therefore, resilience of the start spring 40 will no longer act on the countershaft 27 in consequence.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is a screw tightening machine using a push-start type electric screwdriver, and the mechanical cutting of the electric screwdriver is performed in conjunction with the moving operation of the electric screwdriver. It is related to the device.

Conventional technology In recent years, the driving source for screw tightening machines has changed from air screwdrivers to electric screwdrivers, and among them, push-start type screwdrivers with high torque accuracy are often used for tightening.

An example of the conventional screw tightening machine mentioned above will be described below with reference to the drawings.

FIG. 4 shows a partially sectional side view of the main parts of a conventional screw tightening machine. In FIG. 4, reference numeral 1 is a push-start type electric screwdriver, which has a structure in which when the output shaft 2 is pushed, the driving side and the driven side are mechanically engaged, and at the same time, they are electrically connected by a switch or the like. Reference numeral 3 denotes a block for supporting the electric screwdriver 1, which has a two-part structure and has an elastic synthetic resin 3a pasted on the electric screwdriver gripping part.

Block 3 is a pipe 6 fixed to slide holder 4
Fixed. The slide holder 4 is connected to a slide shaft 8 by a cylinder 7 attached to a fixed plate 6.
It is configured to slide over the top. Reference numeral 9 denotes an intermediate shaft fixed to the output shaft 2 with a pin 10, and the other end is connected to a bit 13 via a universal joint 12 fixed with a pin 11. 14 is a guide pipe for the bit 13.

The operation of the screw tightening machine configured as described above will be explained below.

If the cylinder 7 starts operating to move the slide holder 4 in the direction of the arrow a, and the tip of the bit 13 engages with the screw (not shown) and moves in the direction of the arrow, the electric screwdriver 1 is of the push start type. , output shaft 2
When the electric contacts are closed, the motor rotates and the bit 13 rotates. When the specified screw tightening is completed, the slide holder 4 will move as shown by arrow C.
The bit 13 also returns to the direction of the arrow d, and the mechanical connection within the electric screwdriver 1 is released. Incidentally, when the bit 13 returns in the direction of arrow d, the spring inside the electric screwdriver 1 is acting.

The fifth diagram (b) shows the state in which the screw 16 flowing on the inclined chute 16 enters the catcher 17 and is pushed out by the bit 13, and 18 is at the center of rotation of the catcher 17. This is a pin.

Problems to be Solved by the Invention However, in the above configuration, the electric screwdriver 1
Bit 1 will not rotate unless it is pushed in the direction of the arrow.
3 does not engage with the cross recess of the screw 16, causing the screw 16 to be thrown off in the direction of arrow e as shown in FIG.

There is also a method of mechanically coupling the bit to the electric screwdriver using a separately driven cylinder or the like, but this method requires a large-scale device and increases costs in terms of mechanism and electrical control.

In view of the above-mentioned problems, the present invention provides a spring around the output shaft and intermediate shaft of a push-start type electric screwdriver, which does not act when the electric screwdriver is in a fixed position, but biases the bit toward the electric screwdriver side when the electric screwdriver starts moving. To provide a screw tightening machine that rotates the bit until the bit touches the screw, and smoothly engages the bit and screw.

Means for Solving the Problems In order to solve the above problems, the screw tightening machine of the present invention includes a push-start type electric screwdriver, a block for holding the same, a drive source for moving the block, and a fixed drive source. the bit connected to the output part of the electric screwdriver, a spring that biases the bit toward the electric screwdriver side, and a means for temporarily releasing the pressing force of the spring,
At the return limit of the electric screwdriver, the spring is released from biasing the bit toward the electric screwdriver, and as the drive source continues to move the electric screwdriver, the spring biases the bit toward the electric screwdriver again. It has a configuration.

With the above-described configuration, the present invention rotates the via when the electric screwdriver starts moving, so that the cross section of the tip of the bit smoothly engages with the cross recess of the screw head in the catcher, and after tightening the screw to a specified level, the electric screwdriver is turned. When the bit returns to its normal position, the bushing pressure on the bit is released and the mechanism inside the electric screwdriver is reset.

EXAMPLES Below, a screw tightening machine of the present invention will be explained with reference to the drawings.

FIG. 1 shows a screw tightening machine according to an embodiment of the present invention. In Figure 1, reference numeral 19 is a push-start type electric screwdriver, and when the output shaft 2Q is pushed, the driving side (motor side) and driven side (bit side) are mechanically engaged, and at the same time, they are electrically connected using a switch, etc. The structure is as follows. 21 is made of elastic synthetic resin 2 for the grip part of the electric screwdriver.
1a is attached. The block 21 is fixed to a pipe 23 fixed to a slide holder 22.

The slide holder 22 is configured to slide on a slide shaft 26 by a cylinder 25 attached to a fixed plate 24. An intermediate shaft 27 is fixed to the output shaft 20 with a pin 28, and the other end is connected to a bit 32 fixed with a pin 31 via a universal joint 3° fixed with a pin 29. 33 is a guide pipe for the bit 32. A spring receiver 34 is slidably inserted into the inner diameter surface of the - side pipe 23, and a plate 35 extending from the opening 23a of the pipe 23 is fixed to one end of the spring receiver 34. A thrust bearing 37 is fixed between retaining rings 36 in the intermediate shaft 27, and a retaining ring 38 fitted to the inner diameter of the pipe is attached to the other end of the inner diameter protrusion 34a.
A start spring 40 is biased between the intermediate shaft 27 and the spring seat 39 which is in contact with the intermediate shaft 27 and has a certain clearance. 38b is 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, a trap lever 42 is fixed to the fixed plate 24, and a protrusion 42a of the trap lever 42 comes into contact with the plate 35 when the electric screwdriver 19 returns to its normal position.

In FIG. 2, the trap lever 42 is in contact with the plate 35,
The electric screwdriver 19 is shown in a restored state.

FIG. 3 is a cross section taken along line XX in FIG. 2, and numeral 43 indicates a cover.

Regarding the screw tightening machine configured as above, the following is the first part.
The operation will be explained using FIG. 2, FIG. 3, and FIG.

First, FIG. 2 shows the electric screwdriver 19 in a fixed position and the device in a steady state, but this is similar to FIG. 1.
When the plate 35 moves away from the trap lever 42 while moving by the stroke S, the spring receiver 34 is pushed upward by the elastic force of the spring 4o, and the thrust bearing 37
．． The intermediate shaft 27 moves in the direction indicated by the arrow via the retaining ring 36. Since the spring 4Q is much stronger than the reset spring (not shown) inside the electric screwdriver 19,
The output shaft 20 is pushed toward the electric screwdriver 19 side, and internal mechanisms such as a clutch become in a torque transmitting state. If the switch that maintains the power supply to the electric screwdriver 19 is closed before or after this operation, the motor inside the electric screwdriver 19 (
The bit 32 rotates via the output shaft 20, the intermediate shaft 27, and the universal joint 30 in order to absorb the center deviation between the output shaft 20 and the bit 32 (not shown). The electric screwdriver 19 continues to descend, and the bit 3 attaches to the screw head (not shown).
When the tips of 2 touch, the rotating bit 32 comes into contact with the stationary screw, so the screw head's cross recess and the bit 32
The cross section at the tip of the pit 32 smoothly engages with the screw so that it does not fly out at the tip of the pit 32.

This is the same whether the screw is picked up in advance with the bit 32 or the screw in the catcher is picked up directly.

Next, when the specified screw tightening is completed, the electric screwdriver 19 is pulled up to its original position by the cylinder 25, but as shown in FIG. 2, at the upper limit of the electric screwdriver 19,
A plate 36 fixed to the spring receiver 34 abuts the lower end of the trap lever 34 and compresses the start spring 40.

Therefore, the elastic force of the start spring 40 no longer acts on the intermediate shaft 27, and the reset spring (
(not shown) returns the output shaft 20 in the direction of arrow B, and the mechanism such as the clutch inside the electric screwdriver 19 that was operated to tighten the screw is restored to the reset state.

As described above, according to this embodiment, by providing a spring that biases the bit toward the electric screwdriver side and a means for temporarily releasing the pressing force of the spring, the screw can be rotated while the bit is rotated in advance. Because of this, it is possible to stably connect the pit cross to the screw cross recess.

In the embodiment, the push-start type electric screwdriver 19 was used as the screw tightening drive source, but a push-start type air tool may also be used. Further, although the cylinder 25 is used as the driving source for moving the electric screwdriver 19, it may be driven by a motor or manually.

Effects of the Invention As described above, the present invention provides a push-start type screw tightening tool by providing a spring that biases the bit of the screw tightening tool toward the screw tightening tool, and a means for temporarily releasing the pressing force of the spring. This eliminates the problems caused by poor engagement between the bit and screw that previously occurred in screw tightening machines that use screws as the screw tightening drive source.In addition, the device that rotates the pit before screwing is installed in the pit main shaft in a compact and inexpensive manner. It can be applied to screw tightening machines in general and greatly increases their reliability.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of a screw tightening machine according to an embodiment of the present invention, FIG. 2 is a partially sectional front view of FIG.
FIG. 3 is a partial side view of a partial cross section taken along the line X--X in FIG. 2 when the pits are in contact with each other. 19... Electric screwdriver, 20... Output shaft, 21... Block, 22... Slide holder, 23- mark pipe, 24... mark・Fixing plate, 25...Cylinder f-130...
...Universal joint, 32...Pit, 34...Spring receiver, 35...Plate, 40...Spring, 42... trap lever. Name of agent: Patent attorney Toshio Nakao and 1 other person +'
+ -1'H Takumi Ino C- 20-Output shaft Fig. 3 Fig. 4 Fig. 5

Claims (2)

[Claims] (1) A push-start type screw tightening tool, a block that holds it, a drive source that moves the block, a frame that fixes the drive source, a bit connected to the output part of the screw tightening tool, and a bit that It consists of a spring that biases the bit toward the screw tightening tool and a means for temporarily releasing the pressing force of the spring, and the bias of the spring toward the bit of the screw tightening tool is released at the return limit of the screw tightening tool. A screw tightening machine characterized in that, as the screw tightening tool moves further by the drive source, the spring biases the bit against the screw tightening tool again. (2) The screw tightening machine according to claim 1, wherein the output portion of the screw tightening tool and the bit are connected by a universal joint.