JPH11873A - Bolt/nut fastening machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt/nut fastening machine capable of automatically releasing an outer sleeve from biting a nut after temporarily fastened. SOLUTION: For a bolt/nut fastening machine 1, when temporarily fastening torque is added to a spindle 11 on the output side, a transmitting member 12 mounted between a sleeve 9 on the drive side and the spindle 11 is displaced to the back side in the axial direction of the spindle 11 against compression springs 22, 23 to stop an electric motor on the drive side. In this case, the transmission member 12 is displaced to the front side in the axial direction of the spindle 11 by the compression springs 22, 23, when driving torque on the drive side is removed by the stop of the electric motor, so that the electric motor stopped to be set free state is reversed and the spindle 11 is reversed by inertia force by the reverse of the electric motor to automatically release an outer sleeve from biting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for fastening a nut with a fixed tightening torque lower than the final tightening torque before the nut is fully tightened to a shear bolt with a constant torque (final tightening torque) using, for example, a shear wrench. The present invention relates to a bolt and nut tightening machine for temporarily tightening a shear bolt.

[0002]

2. Description of the Related Art A shear wrench for final tightening includes an inner sleeve for fitting a tip at the tip of a shear bolt and an outer sleeve for fitting a nut. The outer sleeve is rotated by a driving device (electric motor) in a state where the tip is fitted and the nut is fitted to the outer sleeve, thereby tightening the nut to the shear bolt, and the nut is tightened with a constant torque. At this point, the tip of the inner sleeve is subjected to the reaction of tightening the nut by the outer sleeve, so that the tip is sheared.

[0003] As a stage before the nut is fully tightened to the shear bolt using such a shear wrench, temporary tightening (primary tightening) is generally performed. In this temporary fastening operation, the nut is fastened to the shear bolt to a certain torque. The bolt and nut tightening machine for performing the temporary tightening is provided with an outer sleeve for fitting a nut and an inner sleeve for fitting a tip of a shear bolt like a shear wrench for final tightening, and the outer sleeve is driven by a driving device such as an electric motor. , The nut is tightened to a predetermined torque with respect to the shear bolt, and the rotation of the outer sleeve is automatically stopped by detecting the predetermined torque with a torque limiter.

[0004]

However, in such a bolt and nut tightening machine, after the rotation of the outer sleeve is stopped, the tightened nut (or bolt, hereinafter the same) applies to the outer sleeve, that is, the bolt and nut. When trying to remove the tightening machine, the outer sleeve may bite into the nut, making it difficult to remove it.
The conventional bolt and nut tightening machine has no countermeasure against this biting, so that there is a problem that the usability is not good.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bolt and nut tightening machine in which the biting of the outer sleeve with respect to the nut is automatically released after the completion of the tightening and the nut can be easily removed from the tightened nut.

[0006]

According to the present invention, when a predetermined tightening torque is applied to the output-side spindle, the bolt-nut tightening machine according to the first aspect of the present invention intervenes between the drive-side sleeve and the spindle. The transmission member mounted is a bolt and nut tightening machine in which the electric motor on the drive side is stopped by being displaced rearward in the axial direction of the spindle against a compression spring, wherein the transmission member is provided with respect to the sleeve. When the electric motor is displaced rearward while relatively rotating in the nut loosening direction, and the electric motor stops and enters the free state, it is returned to the front side by the compression spring, and the electric motor in the free state is loosened. It is characterized by being configured to reverse in the direction.

According to this bolt and nut tightening machine, when the nut is tightened with a fixed tightening torque, the sleeve is displaced in the rotational direction with respect to the transmission member, whereby the transmission member is displaced rearward in the axial direction of the spindle. . When the transmission member is displaced rearward, the power supply circuit is shut off and the electric motor is stopped, and when an external force is applied, the transmission member is in a free state in which it can rotate in any direction.

On the other hand, when the electric motor is in the free state, the driving torque is removed from the driving side, so that the transmission member is returned to the front side by the compression spring, whereby the sleeve and, consequently, the electric motor in the free state are moved in the nut loosening direction. Reverse. Due to the inertial force of the electric motor in the reverse rotation direction, the transmission member and, consequently, the outer sleeve also reversely rotate, whereby the biting of the outer sleeve against the nut is automatically released.

The bolt and nut tightening machine according to claim 2 is
The bolt and nut tightening machine according to claim 1, wherein one of the sleeve and the transmission member is provided with an inclined groove inclined with respect to the rotation axis, and the other is provided with a groove along the rotation axis.
A steel ball is interposed between the groove and the inclined groove to transmit torque between the sleeve and the transmission member.

According to this bolt and nut tightening machine, the operation and effect according to the first aspect can be reliably obtained with a simple configuration. That is, between the transmission member and the sleeve, an inclined groove inclined with respect to the rotation axis, a groove along the rotation axis, and a steel ball engaging with both grooves are interposed. Thus, when the sleeve is displaced in the rotational direction, the transmission member is reliably displaced in the axial direction.

[0011]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 shows a bolt and nut tightening machine 1 according to the present embodiment. In the figure, reference numeral 2 denotes an electric motor as a drive source of the bolt and nut tightening machine 1. The electric motor 2 is started when the switch 4 is turned on by turning on the trigger 3. The rotation of the electric motor 2 is transmitted to an intermediate shaft 7 via a pinion gear 2a, an intermediate gear 5, and an intermediate gear 6 formed on the output shaft. A bevel gear 7 a is formed at the end of the intermediate shaft 7 and meshes with the bevel gear 8.

The bevel gear 8 is fixed to a sleeve 9 which is connected to the spindle 1 via bearings 10a and 10b.
1 rotatably supported. A transmission member 12 also having a cylindrical shape is disposed on the right side of the sleeve 9 in the drawing. Steel balls 13 are interposed between the transmission member 12 and the sleeve 9 at three equally spaced positions in the circumferential direction.

Each of the steel balls 13 is sandwiched between an inclined groove 9a formed at a position equally divided into the outer peripheral surface of the sleeve 9 and a groove 12a formed at a position divided equally into the inner peripheral surface of the transmission member 12. I have. As shown in FIG. 9, the three inclined grooves 9 a are formed to have a certain length along a direction inclined with respect to the rotation axis of the sleeve 9. The groove 12a is formed to have a certain length along the rotation axis of the transmission member 12. The rotation of the sleeve 9 is transmitted to the transmission member 12 via the steel balls 13 to 13. The rotation axis of the sleeve 9, the rotation axis of the transmission member 12, and the rotation axis of the spindle 11 coincide with each other.

Steel balls 14 are interposed between the transmission member 12 and the spindle 11 at three equally spaced positions in the circumferential direction. Each steel ball 14 has a groove 11 a formed at a fixed length along the rotation axis of the spindle 11, and a transmission member 12.
(Accordingly, the axis of the spindle 11) and the groove 12b formed to have a certain length. The rotation of the transmission member 12 is transmitted to the spindle 11 via the steel balls 14 to 14.

Since the grooves 12a and 12b of the transmission member 12 are respectively formed along their rotation axes, the transmission member 12 is movable in the axial direction with respect to the sleeve 9 and the spindle 11. The sleeve 9, the transmission member 12, the steel balls 13, 14, and the compression spring 2 described later.
2, 23 and the like constitute a torque detecting device.

Next, the spindle 11 is rotatably supported by bearings 15 and 16. A torque adjusting plate 20 and a thrust bearing 21 are arranged on the spindle 11 near the rear end side (right end side in the figure) of the spindle 11 so as to be axially movable. The compression springs 22 and 23 are interposed between the thrust bearing 21 and the transmission member 12. The transmission member 12 is urged leftward in the figure by the two compression springs 22 and 23.
Numeral 3 is held at the front end portion relatively to the inclined groove portion 9a, and is held at the rear end portion relatively to the groove portion 12a.

The compression spring 22 has a slightly smaller spring constant and a larger free length than the compression spring 23. In the state shown in FIGS. 1 to 4, since the inner compression spring 23 does not abut on the bearing 21, the inner compression spring 23 has a free length in which no urging force is exerted. The effect of this will be described later.

An external torque necessary for the transmission member 12 of the torque detecting device to start moving (hereinafter referred to as "temporary tightening torque". This temporary tightening torque corresponds to a fixed tightening torque described in claim 1). ) Is determined by the urging force of the compression spring 22 or the compression spring 23 or both, and the respective urging forces can be arbitrarily set within a certain range by moving the torque adjusting plate 20 in the axial direction of the spindle 11. Can be. In other words, the temporary tightening torque can be set higher because the urging force of the compression springs 22 and 23 increases as the torque adjusting plate 20 moves to the left in the drawing, and can be set higher as the torque adjusting plate 20 moves to the right in the drawing. Since the urging force of the compression springs 22 and 23 becomes small, it can be set low. The bolt and nut tightening machine 1 according to the present embodiment includes a torque setting mechanism that can arbitrarily set a temporary tightening torque within a certain range. This torque setting mechanism will be described later.

Next, as shown in FIG. 1, a pinion gear 11b is formed at the tip of the spindle 11, and this pinion gear 11b meshes with the first planetary gear 25a of the planetary gear unit 25. The driving force transmission path from the spindle 11 to the outer sleeve 30 on the output side and the shear bolt tightening mechanism need not be particularly changed.
This will be briefly described below.

An outer sleeve 30 is rotatably mounted in the front end opening of the housing 1a of the bolt and nut tightening machine 1 so as not to move in the axial direction. A nut fitting portion 30c for fitting a nut of a shear bolt is formed at the tip of the outer sleeve 30. An intermediate sleeve 33 is rotatably supported on the inner peripheral side of the outer sleeve 30 via bearings 31 and 32. The intermediate sleeve 33 has a surface gear 34 formed on the rear end surface thereof.
Through the second carrier 25b of the planetary gear mechanism 25. Therefore, the intermediate sleeve 33 is
It rotates integrally with the carrier 25b.

The first planetary gear 25a and the carrier 25
The second planetary gear 25c, which is rotatably supported by b, meshes with the first and second internal gears 30a, 30b formed on the inner peripheral surface of the outer sleeve 30. Spindle 1
1 rotates and the first planetary gear 25a rotates to rotate the outer sleeve 30. When rotation resistance is added to the outer sleeve 30, the first planetary gear 25a revolves,
Therefore, the first carrier 25d that supports the rotation is rotated. After rotation of the first carrier 25d, the second carrier 25
b rotates, whereby the intermediate sleeve 33 rotates.

An inner sleeve 35 is mounted on the inner peripheral side of the intermediate sleeve 33 so as to be movable in the axial direction. A tip fitting portion 35 a for fitting a tip of a shear bolt (not shown) is provided at a tip of the inner sleeve 35. A compression spring 36 is interposed between the inner sleeve 35 and the second carrier 25b. Therefore, the inner sleeve 35 is urged in a direction to protrude into the nut fitting portion 30c of the outer sleeve 30.

On the outer peripheral surface of the inner sleeve 35, a plurality of meshing teeth 35b to 35b are formed in the circumferential direction along the axial direction, and the inner circumferential side of the intermediate sleeve 33 is substantially half of the rear side in the axial direction. Are formed with a plurality of meshing teeth 33a to 33a in the circumferential direction along the axial direction. Therefore, the inner sleeve 35 is spline-fitted to the intermediate sleeve 33, whereby the inner sleeve 35 and the intermediate sleeve 33 rotate integrally.

On the inner peripheral side of the inner sleeve 35, a slick preventing pin 37 for preventing slicking of the chip is supported so as to be movable in the axial direction, and a direction in which the compression spring 38 projects into the chip fitting portion 35a. Has been energized. The chip is completely fitted into the chip fitting portion 35a of the inner sleeve 35, and the slick prevention pin 37 is
When the inner sleeve 35 is retracted, the stopper 39 provided on the peripheral surface of the inner sleeve 35 is retracted to the inner peripheral side of the inner sleeve 35, and the inner sleeve 35 can move to the inner side of the outer sleeve 30. According to this configuration, the nut cannot be fitted to the nut fitting portion 30c of the outer sleeve 30 unless the tip is completely fitted to the tip fitting portion 35a of the inner sleeve 35. Chip licking is prevented.

According to the driving force transmission path and the tightening mechanism configured as described above, the inner sleeve 35 is retracted while the tip of the shear bolt is completely fitted into the tip fitting portion 35a of the inner sleeve 35. A nut (not shown) of a shear bolt is fitted to the nut fitting portion 30c of the outer sleeve 30. At this stage, the inner sleeve 35 is spline-fitted to the intermediate sleeve 33. In this state, when the trigger 3 is turned on to rotate the spindle 11, the outer sleeve 30 rotates and the nut is tightened to the shear bolt.

When the nut is tightened with the temporary tightening torque, the torque at this time is added to the transmission member 12 of the torque detecting device via the spindle 11, so that FIG.
The sleeve 9 (drive side) is displaced in the nut tightening direction with respect to the transmission member 12 as shown in FIG. Since the steel balls 13, 13 interposed between the transmission member 12 and the sleeve 9 are fitted in the inclined grooves 9 a that are inclined with respect to the rotation axis, the sleeve 9 rotates in the rotation direction with respect to the transmission member 12. , The transmission member 12 is displaced rearward in the axial direction, whereby the temporary tightening torque is detected. Thus, when the torque detecting device detects the temporary tightening torque, the rotation of the outer sleeve 30 is automatically stopped by a rotation drive automatic stop mechanism described below.

As shown in FIG. 2, a tapered portion 12c and a cylindrical portion 12d are formed on the rear outer peripheral surface of the transmission member 12. A guide rod 40 is abutted against the tapered portion 12c or the cylindrical portion 12d. This guide rod 4
Numeral 0 is supported by the housing 1a so as to be movable in the vertical direction, and the lower end thereof is connected to the D
It has reached the inside of the mold handle portion 1b.

The trigger 3 and the main switch 4 are arranged in the D-shaped handle portion 1b. The trigger 3 is urged to the protruding side (off side) by a compression spring 3a. The main switch 4 has an operation piece 4a. The operation piece 4a is urged in the protruding direction, that is, the off side, by a built-in elastic means. Above the trigger 3, an intermediate member 41 is rotatably mounted via a support shaft 41a. On the left side of the intermediate member 41 with respect to the support shaft 41a, an engagement piece 41b is provided so as to protrude laterally, and the lower end of the guide rod 40 is abutted against the engagement piece 41b from above. ing. On the other hand, the intermediate member 41
A switch operating member 42 is rotatably mounted on the right side of the support shaft 41a via a support shaft 42a.

One end 43 of the torsion spring 43 is attached to the support shaft 42a.
Since a is abutted from above, the intermediate member 41 is urged in the clockwise direction in the figure around the support shaft 41a, that is, in a direction to move the guide rod 40 upward.

The switch operating member 42 rotatably and suspendedly supported on the right side in the drawing of the intermediate member 41 via the support shaft 42a extends downward, and
a, and has a length that allows contact with the engaging portion 3 b provided on the trigger 3.

The thus-configured automatic rotation drive stop mechanism functions as follows. 1 and 2 show a state in which the trigger 3 is not pulled (on operation). Therefore, the operation piece 4a of the main switch 4 is located on the protruding side (off side). In addition, in this non-drive state, the spindle 11 does not rotate, so that the torque detecting device does not operate, and thus the transmission member 12 is not displaced rearward. For this reason, the guide rod 40 is located at the upper position, and its upper end is abutted against the cylindrical portion 12d. At this time, the switch operating member 42 is located at the lower position by the torsion spring 43, and the lower end thereof is in contact with the engaging portion 3b of the trigger 3.

When the trigger 3 is pulled (turned on) from this non-drive state as shown in FIG. 3, the switch operating member 42 is pushed by the engaging portion 3b and the switch operating member 42 is rotated counterclockwise around the support shaft 42a in the figure. The operation piece 4a is pushed by this, and the main switch 4 is turned on. When the main switch 4 is turned on, the electric motor 2 is rotated by a power supply circuit (not shown), whereby the outer sleeve 30 is rotated via the above-described driving force transmission path. Outer sleeve 30
When the nut rotates to the temporary tightening torque with respect to the shear bolt, the transmission member 12 of the torque detecting device is displaced rearward against the compression spring 22 as shown in FIGS. 4 and 9B. I do. At this stage, the steel balls 13,
Reference numeral 13 moves from the front end to the rear end of the inclined groove 9a, and the transmission member 12 moves rearward by the moving distance of the steel balls 13, 13.

When the transmission member 12 is displaced rearward, the guide rod 40 abutted against the cylindrical portion 12d is displaced downward due to the rearward displacement of the tapered portion 12c. When the guide rod 40 is displaced downward, the engagement piece 41b abutting on the lower end thereof is pushed downward, whereby the intermediate member 41 rotates counterclockwise against the torsion spring 43.

When the intermediate member 41 rotates counterclockwise,
Since the switch operation member 42 is pulled upward, the tip end thereof is disengaged from the engagement portion 3b of the trigger 3. When the distal end is disengaged from the engaging portion 3b, the switch operating member 42 is pushed by the operating piece 4a of the main switch 4 to rotate leftward (clockwise) in the figure, and the main switch 4 is turned off to turn off the power supply circuit. Is cut off, whereby the electric motor 2 is stopped, and the rotation drive of the outer sleeve 30 is automatically stopped.

Next, the torque setting mechanism will be described.
As described above, this torque setting mechanism is a mechanism for changing the temporary tightening torque.
0 in the axial direction of the spindle 11 to move the compression spring 2
This is achieved by changing the biasing force of the second and the third.
That is, the temporary tightening torque is set higher as the torque adjusting plate 20 is moved to the left in the drawing, and is set lower as the torque adjusting plate 20 is moved to the right in the drawing. The state shown in FIGS. 1 to 4 is a state in which the torque adjustment plate 20 has moved to the rightmost side, and thus shows a state in which the temporary tightening torque is set to the lowest. On the other hand, the state shown in FIG. 5 is a state in which the torque adjustment plate 20 has moved to the leftmost side, and thus shows a state in which the temporary tightening torque is set to the highest.

The movement of the torque adjusting plate 20 can be easily performed from the outside by rotating the torque adjusting dial 50 disposed at the rear end of the housing 1a. The torque adjustment dial 50 is rotatably attached to an outer peripheral side of a shaft portion 1c provided at a rear end of the housing 1a. In addition, a bearing 16 for rotatably supporting the rear end of the spindle 11 is fixed inside the shaft portion 1c.

On the inner peripheral surface of the torque adjusting dial 50, two inclined surfaces 50b, 50b whose height gradually changes within a range of 180 ° as shown in FIG. I have. At the highest position of the two inclined surfaces 50b, a stepped portion 50c for prevention of climbing over is formed in a projecting shape. The two engagement pieces 20a, 20a of the torque adjustment plate 20 are provided on the two inclined surfaces 50b, 50b.
Are brought into sliding contact.

As shown in FIG. 7, the torque adjusting plate 20 has a disk shape having an insertion hole 20b at the center for inserting the spindle 11, and the engaging pieces 20a, 20a are integrally formed on the outer periphery thereof. Is formed. Both engagement pieces 20a, 20a are formed to protrude outward from sides opposite to each other. Further, as shown in FIG. 7 (B), the two engagement pieces 20a, 20a are provided slightly inclined with respect to the surface direction of the main body of the plate 20 in accordance with the inclination angle of the inclined surface 50b. , Thereby the inclined surface 5
A good sliding contact state with respect to 0b and 50b is obtained.

In the torque adjusting plate 20 thus configured, the two engaging pieces 20a, 20a are respectively provided on the inclined surfaces 50a.
b is attached to the spindle 11 in a state of sliding contact. In addition, the torque adjusting plate 20 has two engaging pieces 2.
By inserting 0a and 20a into insertion grooves 1d and 1d formed in the shaft portion 1c of the housing 1a, the housing 1a is prevented from rotating with respect to the shaft portion 1c. According to this configuration, when the torque adjustment dial 50 is rotated within the range of 180 °, the two engagement pieces 20a, 20a of the torque adjustment plate 20 relatively move on the inclined surfaces 50b, 50b, and the torque adjustment is performed. The plate 20 moves in the axial direction. That is, the rotational operation of the torque adjustment dial 50 is performed in the spindle axial direction of the torque adjustment plate 20 by the operation converting means interposed between the torque adjustment dial 50 and the torque adjustment plate 20 and including the inclined surface 50b and the engagement piece 20a. Converted to move to.

With such a mechanism, the amount of compression of the compression springs 22 and 23 can be changed by moving the torque adjusting plate 20 by an external operation, thereby easily changing the setting of the temporary tightening torque.

Here, the torque adjusting plate 20 is shown in FIGS.
As shown in FIG. 4, in a state where the temporary tightening torque is set to the lowest value by moving to the rightmost side, the inner compression spring 23 is not effective. For this reason, in the initial fixed range in which the set torque is gradually increased by rotating the torque adjustment dial 50 from the minimum value, only the outer compression spring 22 is in effect, so that the set torque is moderate. Adjustments (fine adjustments) can be made. When the adjusting dial 50 is rotated by a fixed angle to the torque increasing side, and the inner compression spring 23 comes into contact with the bearing 21 to exert a biasing force, the temporary tightening torque is determined by the biasing force of the two compression springs 22 and 23. Is performed, so that a larger temporary tightening torque can be set. By using the two compression springs 22 and 23 having different free lengths as described above, two types of adjustments can be performed, that is, a fine adjustment range of the temporary tightening torque and a wider adjustment allowance range.

The adjustment position of the adjustment dial 50 does not shift due to vibration or the like. As shown in FIG. 8, a stopper projection 51 which is appropriately elastically urged is attached to the outer periphery of the shaft portion 1c. On the other hand, adjustment dial 5
A number of recesses 50a to 50a are formed on the inner circumferential surface of the zero at regular intervals over the entire circumference. The adjustment position of the adjustment dial 50 is held by the stopper projection 51 being elastically fitted into the concave portion 50a. Also,
When the adjustment dial 50 is rotated, the stopper protrusion 50a
Is fitted into each of the recesses 50a by its elastic force, so that the operator can get a rugged feeling, and thus the feeling of use is improved. In addition, since the stopper projections 51 are elastically fitted into the respective recesses 50a, an appropriate resistance can be obtained during the rotation operation, so that a reliable adjustment can be performed, and in this respect, the usability is improved. .

Next, as described above, the outer sleeve 30
When the nut of the shear bolt is tightened with a predetermined temporary tightening torque, the transmission member 12 of the torque detecting device is displaced rearward and the power supply circuit is automatically cut off. Usually it is in a state of biting the nut. Therefore, if no countermeasures are taken against this biting, there is a problem that it is difficult to remove the outer sleeve 30 from the nut. In this regard, the bolt and nut tightening machine 1 according to the present embodiment is configured so that the biting state after the tightening is automatically released.

That is, the inclined grooves 9a, 9a formed in the sleeve 9 of the torque detecting device correspond to those shown in FIGS.
As shown in (B), it is formed along a direction inclined with respect to the rotation axis of the sleeve 9. For this reason, the nut of the shear bolt is tightened with the temporary tightening torque, and this torque is applied to the spindle 11 and thus the transmission member 12, so that the rotation of the transmission member 12 is prevented. Therefore, FIG.
As shown in (B), the sleeve 9 is displaced from the transmission member 12 by a slight angle α in the nut tightening direction (the lower side in the figure). When the sleeve 9 is displaced with respect to the transmission member 12,
The transmission member 12 is formed by the action of the inclined groove 9a and the steel ball 13.
Are displaced axially rearward (to the right in the figure) by a distance L. When the transmission member 12 is displaced rearward, the power supply circuit is shut off as described above, and the electric motor 2 stops. When the power is cut off, the electric motor 2 enters a free state in which it can rotate in any direction when an external force is applied.

On the other hand, when the electric motor 2 (drive side) is in a free state, that is, a state in which the electric motor 2 can rotate in the nut loosening direction,
The transmission member 12 is moved forward by a distance L by the compression springs 22 and 23.
The sleeve 9 is returned by the angle α in the nut loosening direction by the action of the inclined groove 9a and the steel ball 13.

When the electric motor 2 in the free state and thus the sleeve 9 rotate in the nut loosening direction, the inertia force (inertia) causes the transmission member 12 and the spindle 11 to rotate.
Consequently, the outer sleeve 30 slightly rotates in the nut loosening direction, whereby the biting of the outer sleeve 30 with respect to the nut is automatically released.

According to the embodiment described above, the biting of the outer sleeve 30 with respect to the nut is automatically released after the completion of the temporary tightening of the nut, so that the bolt and nut tightening machine 1 can be easily removed from the nut. In this regard, the bolt and nut tightening machine 1
Can be improved.

Since the groove 9a is inclined with respect to the rotation axis to obtain the above-mentioned automatic releasing function of the biting, no special member is required separately, and therefore, the above-mentioned operation is achieved without increasing the cost. The effect can be obtained.

In the embodiment described above, the case where the present invention is applied to a temporary tightening machine of a shear bolt is exemplified. However, it goes without saying that the present invention is applicable to a shear wrench for final tightening. A bolt-nut tightening machine of a type having a receiving projection and configured to contact the adjacent projection with a bolt, a nut or the like so as not to transmit a reaction force accompanying the tightening of the nut or the like to the tool body (Japanese Patent Publication No. 6-32911 or the tool disclosed in Japanese Patent Publication No. 6-71712.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, and is an overall side view of a bolt and nut tightening machine. In addition, the internal structure of the main part is shown by the fracture of the housing.

FIG. 2 is a view showing an internal structure of a rear portion of the bolt and nut tightening machine, and is a view showing a state of each part when the trigger is not pulled and not used.

FIG. 3 is a diagram showing an internal structure of a rear portion of the bolt and nut tightening machine, showing a state of each portion at the time of driving by pulling a trigger.

FIG. 4 is a diagram showing an internal structure of a rear portion of the bolt and nut tightening machine, and is a diagram showing a state of each portion at a time point when a temporary tightening torque is detected by a torque detecting device and a main switch is turned off.

FIG. 5 is a view showing an internal structure of a rear portion of the bolt and nut tightening machine, and is a view showing a state where a temporary tightening torque is set to a maximum value.

FIG. 6 is a development view of an inner peripheral surface of the torque adjustment dial.

FIG. 7 is a single perspective view of a torque adjustment plate.

8 is a sectional view taken along line (8)-(8) of FIG.

9A and 9B are diagrams showing a positional relationship between the sleeve and the transmission member in the torque detection device, wherein FIG. 9A shows a state in which the transmission member is located on the front side, and FIG. This shows a state in which the transmission member has been displaced rearward.

[Description of Signs] 1 ... Bolt / Nut Tightening Machine 2 ... Electric Motor 9 ... Sleeve, 9a ... Slope Groove 11 ... Spindle, 11a ... Groove 12 ... Transmission Member, 12a, 12b ... Groove 13, 14 ... Steel Ball 20 ... Torque Adjustment Plates 22, 23: Compression spring 30: Outer sleeve, 30c: Nut fitting part 35: Inner sleeve, 35a: Tip fitting part 50: Torque adjustment dial

Claims (2)

[Claims] When a certain tightening torque is applied to an output-side spindle, a transmission member interposed between a drive-side sleeve and the spindle causes an axial rearward of the spindle to oppose a compression spring. A bolt-and-nut tightening machine in which the driving-side electric motor is stopped by being displaced to the side, wherein the transmission member is configured to be driven by the compression spring when the driving torque on the driving side is removed by stopping the electric motor. A bolt and nut tightening, wherein the electric motor which has been displaced to the front in the axial direction of the spindle and is stopped and in the free state reversely rotates, and the spindle is reversely rotated by inertia force due to the reverse rotation of the electric motor. Machine. 2. The bolt and nut tightening machine according to claim 1, wherein one of the sleeve and the transmission member is provided with an inclined groove inclined with respect to the rotation axis, and the other is provided with a groove along the rotation axis. A bolt and nut tightening machine, wherein a torque is transmitted between the sleeve and the transmission member by interposing a steel ball between the groove and the inclined groove.