JPS6055267B2 - impact wrench - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to impact wrenches, and in particular to impact wrenches used in various industrial fields for torque tightening of important threaded joints.

The hammer is brought into engagement with the anvil after the rotational speed of the drive shaft is accelerated to a desired number, and the so-called "low impact" impact wrench with a low impact speed of 2 to 3 strokes/second is well known in the art. It is.

Such impact wrenches have a synchronization device that fully engages the impact jaws of the hammer and anvil. This type of impact wrench lacks vibration, high specific power (ratio of impact energy to tool mass) and the possibility of accurate tightening of threaded joints. Furthermore, such impact wrenches are relatively reliable. An impact wrench consisting of a hammer with impact jaws, an axially movable anvil with impact jaws and a locking device that provides an axial space between the hammer and the impact jaws of the anvil until the hammer has acquired a preset rotational speed. (U.S. Pat. No. 3,804
, No. 180, Class 173-15) is well known in the art. Providing the impact wrench with such a device prevents the impact from being transmitted with incomplete engagement of the impact jaws of the hammer and anvil, thus considerably reducing wear and ensuring stable impact energy. I can do it,
Moreover, the vibration of the casing can be eliminated. however,
This impact wrench cannot operate in an automatic cycle to deliver a series of blows and cannot be mass produced. Furthermore, an axially immobile anvil whose casing has impact jaws;
a composite hammer formed by a drive part of a drive body connected to an output shaft, an outer driven part with an impact jaw and an inner driven part, and a pre-interacting of the hammer and anvil before engagement of the impact jaws; Impact wrenches (US Pat. No. 3,952,814) having devices are well known in the art. This device consists of a spring loaded locking member positioned relative to the impact jaw of the hammer and the cam surface of the anvil. This construction of the impact wrench allows full engagement of the impact jaws of the hammer and anvil to be achieved during operation of the automatic hammer cycle.

The spring-loaded locking member and inner driven part of the hammer of the impact wrench are adapted to the hammer, so that the hammer is too long.

Furthermore, the camming surface of the anvil is provided on a tubular member that is attached to and projects from the anvil in the direction of the hammer, thus increasing the axial dimension of the impact wrench. Furthermore, prior art impact wrenches have ball bushers that cooperate with the locking member, which makes the construction more complex. The present invention provides a device for pre-interacting the hammer and anvil and an inner driven part of the hammer configured to simplify the impact wrench construction, improve its reliability of operation and reduce its axial dimensions. Regarding impact wrenches.

The object of the invention is to provide a casing adapted to an axially stationary anvil with impact jaws and an axial bore, a spindle connected to the anvil for rotational movement together with each other, a motor for rotational movement together with each other. A composite hammer having a coupled drive part, an outer driven part and an inner driven part having an impact jaw engageable with the impact jaw of the anvil, the outer driven part and the inner driven part of the hammer having rotational movement relative to each other and in a coupled manner. a flyweight connected to the hammer drive part and disposed between the hammer drive part and the hammer outer driven part, an actuation spring and a return mounted between the hammer driven part; axially movable with respect to the drive part of the hammer and the anvil under the action of a spring; a spring-loaded locking member disposed with respect to the impact jaw of the hammer; and a camming surface of the anvil; In an impact wrench comprising a device for pre-interacting with the hammer and the anvil prior to engagement, the spring-loaded locking member is arranged within the inner side of the hammer in the axial space between the impact jaws of the hammer and anvil. attached to a driven part, a counterbore being provided in the axial bore of the anvil for receiving the inner driven part of the hammer and the actuation spring mounted between the inner driven part of the hammer and the anvil; This is achieved by using an impact wrench characterized by:

Therefore, by adapting the inner driven part of the hammer to the counterbore of the anvil and the spring-loaded locking member to the inner driven part of the hammer, the construction of the impact wrench is considerably simplified, and the reliability of the impact clutch is improved. will be improved.

Furthermore, the axial dimensions of the tool reduce mass and increase the working capacity of the impact wrench. According to one embodiment of the invention:
The inner driven part of the hammer consists of a sleeve that is axially movable with respect to a shaft arranged in the casing.

Preferably, the inner driven part of the hammer has an axially extending projection facing the motor, and the outer driven part of the hammer has a recess for receiving the axially extending projection of the inner driven part of the hammer. According to another embodiment of the invention, the inner driven part of the hammer consists of an axially movable intermediate shaft, one end of which is journalled in the axial bore of the anvil. According to the invention, the spring-loaded jaw member has an anvil-facing bevel capable of engaging a camming surface of the anvil comprising the impact jaw. The impact wrench according to the invention will be explained in detail below with reference to the drawings.

Each impact wrench shown in FIGS. 1 and 2 includes a casing 1 fitted with an anvil 2 having an impact jaw 3;
a composite hammer with an impact jaw 4 engageable with the impact jaw 3 of the anvil, a drive for rotating said hammer, and a cam surface in the formation of a spring-loaded jaw member 5 and a bevel 6 on the impact jaw 3 of the anvil 2; (FIG. 3) consists of a device for the preliminary interaction of the hammer and anvil before the engagement of the impact jaws 3 and 4, respectively (FIG. 3).

The anvil 2 (Figs. 1 and 2) is supported on the axially stationary casing 1 and rotates with the anvil 2 or is made integrally with the anvil 2, as shown in Figs. 1 and 2. The spindle 7 is connected to the spindle 7.

The spindle 7 is supported in a bushing 8, the end 9 of the spindle extending outside the casing being square in cross-section for the attachment of a socket wrench. The anvil 2 has an axial bore 10 and a counterbore 11.

The composite hammer is formed by a driving part 12, an outer driven part 13 having an impact jaw 4 and mounted inside the driving part 12 of the hammer, and an inner driven part 14 received in the counterbore 11 of the anvil 2. Furthermore, a spring-loaded locking member 5 is attached to the inner driven portion 14 of the hammer and positioned relative to the impact jaw 4 of the hammer as shown in FIGS. 1 and 2. The driving body that rotates the hammer is an electric motor 15 as shown in FIG.
It consists of an air motor 16 as shown in the figure.

In the embodiment shown in FIG. 2, a conventional electric motor (eg, a universal commutator motor or a squirrel cage induction motor) is used.

The electric motor 15 of the percussion wrench shown in FIG. 1 has a fixed rotor 17 and a rotating stator 18. The rotor 17 is located within the bore of the casing 1 and within the anvil 2. It is attached to a fixed shaft 19 which is journaled in the axial bore 10 of the. The inner follower part 14 of the hammer consists in this example of a sleeve 14a with a radial bore 20 arranged at the level of the axial space between the anvil and the impact jaws 3 and 4 of the hammer. ．． A spring loaded locking member 5 is attached to the bore 20. The driving part 12 of the hammer is fixedly attached to the stator 18 of the electric motor 15 which rotates with it, and also includes a cylindrical guide cage 21 surrounding the stator 18 of the electric motor, a shaft 19
It consists of a support (22) mounted on a bearing 23 of the shaft 19, and a cover 24 mounted on the bearing of the shaft 19, the support 22 and the cover 24 being fixedly fastened to the guide cage 21. cylindrical guide cage 21
has an inner, eg hexagonal surface 26 (FIG. 4).

The inner 14 (FIG. 1) and outer 13 driven parts of the hammer are mounted on a fixed shaft 19 and connected to the drive part 12 of the hammer and to each other for combined rotational movement. The driven parts of the inner 14 and outer 13 of the hammer are axially movable with respect to the drive part 12 of the hammer and the anvil 21 under the action of a flyweight 27 consisting of a ball, a return spring 28 and an actuation spring 29. The flyweight 27 is arranged between the outer driven part 13 of the hammer and the support 22 of the drive part 12 of the hammer, the outer driven part 13 of the hammer having a bevel 30 facing the electric motor 15 and furthermore a support The body 22 has a protrusion 3 facing the anvil 2
1 (Figure 5).

The flyweight 27 is arranged between the bevel 30 and the protrusion 31. The outer driven part 13 (FIG. 1) of the hammer is connected to the inner hexagonal shaped surface 26 (the fourth
The outer driven part 13 of the hammer rotates together with the drive part 12 of the hammer.

Additionally, the outer driven part 13 of the hammer (FIG. 6) has two recesses 33 that engage the inner driven part 14 of the hammer, and the inner driven part 14 of the hammer has two recesses facing the electric motor received in the recesses 33. It has a protrusion 34 extending in the axial direction. Hammer driven parts 13 and 14 and driving part 1
2 (FIG. 1), the driven parts 13 and 14 of the hammer are rotatable and axially movable. The return spring 28 is installed between the outer driven part 13 and the inner driven part 14 of the hammer, and its one end abuts against the end surface of the inner driven part 14 and the other end contacts the end of the inner driven part 13. It is accepted into borehole 35.

An actuation spring 29 is received in the counterbore 11 of the anvil 2 between the hammer inner driven part 14 and the anvil 2, one end of which is provided for supporting the hammer inner driven part 14 of the anvil 2 counterbore 11. The other end rests against the shoulder of the inner driven part 14 of the hammer as shown in FIG.

The spring-loaded locking member 5 has an anvil-facing bevel 37 that is engageable with the bevel 6 of the impact jaw 3 of the anvil 2.

The spring-loaded locking member 5 (FIG. 7) has a circular cross section;
Each locking member has a flat surface 38 for positioning the locking member in the bore 20.

The locking member 5 is held by a ring 39 and a retaining ring 40 to prevent it from falling out of the bore. As shown in FIG. 2, the impact wrench is powered by an air motor 16 of suitable known construction.
, the air motor 16 of which drives the hammer drive part 12
It has an output shaft 41 to which is fixed.

The end of the shaft 41 has a triangular cross section and an axial bore 42
has. The shaft 41 supports a disk 43 having an inner trihedral surface 44 (FIG. 8) and an outer hexagonal surface 45. The drive part 12 of the hammer is externally attached to the disc 43 and has an internal hexagonal surface, the drive part 12
The disk 43 is connected to the shaft 41 by a pin 46 (FIG. 2) to prevent the disk 43 from moving in the axial direction. The outer driven part 13 of the hammer has an axial bore counterbore 47 and an outer hexagonal surface 48 (FIG. 9);
FIG. 9) engages the drive part 12 of the hammer for a coupled rotational movement and axial movement relative to the drive part 12.

The inner driven part 14 of the hammer (FIG. 2) extends from an intermediate shaft 14b passing through the axial bore of the outer driven part 13 of the hammer and journaled in the axial bore 10 of the anvil 2 and the bore 42 of the drive shaft 41. Become. The inner driven part 14 engages the disk 43 along three surfaces 44 as shown in FIG.
and can be moved axially with respect to the outer driven part 13, the anvil 2 and the drive part 12 of the hammer. The inner driven part 14 (FIG. 2) or intermediate shaft 14b of the hammer is connected to the impact jaws 4 and 3 of the hammer and the anvil 2.
It has a radial bore 49 made at the level of the axial space between.

The bore 49 accommodates the spring loaded locking member 5. The axial movement of the driven parts 13 and 14 of the hammer is caused by a flyweight 50 consisting of a ball, a return spring 51 and an actuation spring 52.

The flyweight 50 is mounted on the outer driven part 13 of the hammer and the protrusion 54 of the disc 43 within the recess formed by the beveled surface 53 provided on the disc 43 and the outer driven part 13.
(Fig. 10). Return spring 51 (second
) is arranged between the driven parts 13 and 14 of the hammer, one end of which is received in the counterbore 47 of the outer driven part 13 of the hammer, and the other end formed by a ring 55. Inner driven component 14 (i.e. intermediate shaft 14b
) against the shoulder of the person. The actuating spring 52 is received in the counterbore 11 of the anvil 2 between the inner driven part 14 of the hammer and the anvil 2, and one end of the actuating spring 52 abuts a shoulder 56 of the intermediate shaft 14b, and the other end rests against the shoulder 56 of the intermediate shaft 14b. It comes into contact with a bearing 57 arranged in the counterbore 11. The spring loaded locking member is
It has a bevel 58 facing the anvil 2 that can engage the bevel 6 of the impact jaw 3 (FIG. 11) of the anvil 2.

The spring-loaded locking member 5 has a flat portion 59 (FIG. 12) located within the bore 49 of the intermediate shaft 14b and is held against falling by an expansion ring 60.

The impact wrench has a main handle 61 (FIG. 1), a side handle 62 and a push button 63 for starting the motor.

The impact wrench shown in FIGS. 1 and 2 operates in the following manner.

A socket wrench (not shown) is attached to the spindle 7 (FIGS. 1 and 2) and applied to the threaded fixture.

After the air motor 16 (FIG. 2) or electric motor 15 (FIG. 1) is energized, the hammer is accelerated and rotational movement is transmitted to the drive part 12 and driven parts 13 and 14 of the hammer. As the hammer speed increases, the flyweights 27 or 50 (FIG. 2) move from the center to the periphery under the action of centrifugal force, thus acting on the beveled surface of the outer driven part 13 of the hammer and causing an ambience. - An axial movement in the direction of the lever 2 occurs so as to compress the spring 51 (FIG. 2) or 28 (FIG. 1). When the outer driven part 13 of the hammer performs an axial movement, the driven part 14, i.e. the sleeve 14
a (Fig. 1) or the intermediate shaft 14b (Fig. 2) is connected to the spring 29.
7 (Fig. 1) or 52 (Fig. 2). The spring-loaded locking member 5 has a bevel 37 of the locking member 5.
(FIG. 1) or 58 (FIG. 2) engages the bevel 6 of the impact jaw 3 of the anvil 2 until the impact jaw 4 of the hammer can be brought into engagement with the impact jaw 3 of the anvil 2. Upon this engagement, the spring-loaded locking member 5 is arranged in the bore 49 of the inner driven part 14 (
2) or 20 (FIG. 1), the impact jaws 4 of the hammer are then arranged opposite the impact jaws 3 of the anvil 2, so that the springs 29 (FIG. 1) or 52 (FIG. (Fig.) is completely compressed, and the impact is on the spindle 7.
The kinetic energy stored by the hammer is transferred to the threaded joint tightened by the hammer. At the time of impact, the rotational speed of the hammer drops to zero and the flyweight 50 (FIG. 2) or 27 (FIG. 1) returns from the periphery to the center.

The spring 28 (FIG. 1) or 51 (FIG. 2) retracts the outer driven part 13 of the hammer away from the anvil 2 and forces the impact jaw 4 of the hammer out of engagement with the impact jaw 3 of the anvil 2. Can be retracted. Furthermore, the spring-loaded locking member 5 is returned to its initial position under the impact jaws 14 of the hammer, and the inner driven part 14 of the hammer
2) or 29 (returned by FIG. 1).The above cycle is then repeated (with the motor rotating).
, the desired amount of energy is transferred to the threaded joint in order to tighten it.

[Brief explanation of the drawing]

1 is a longitudinal sectional view of an impact wrench according to the invention with an electric motor; FIG. 2 is a fragmentary longitudinal sectional view of an impact wrench according to the invention with an air motor;
Figure 3 is a cross-sectional view taken along line ■-■ in Figure 1, Figure 4 is a cross-sectional view taken along line ■-■ in Figure 1, and Figure 5 is a cross-sectional view taken along line ■-■ in Figure 1.
6 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 7 is a sectional view taken along the line ■-■ in FIG. 1,
Figure 8 is a cross-sectional view taken along line ■-■ in Figure 2, Figure 9 is a cross-sectional view taken along line ■-■ in Figure 2, Figure 10 is a cross-sectional view taken along line X-X in Figure 2, and Figure 11 is a cross-sectional view taken along line The figure is a sectional view taken along line 2--M in FIG. 2, and FIG. 12 is a sectional view taken along line 2--2 in FIG. 2...Anvil, 3...Anvil impact jaw, 4
... Hammer impact jaw, 5 ... Funeral member, 10
... Axial bore, 11... Counterbore, 12... Drive part of the hammer, 13... Outer driven part of the hammer,
14... Inner driven part of hammer, 14a... Sleeve, 14b... Intermediate shaft, 33... Recessed part, 34...
・Protrusion, 370-・Bevel.

Claims (1)

Claims: 1. A casing adapted to an axially stationary anvil with impact jaws and an axial bore; spindles connected to the anvil for rotational movement together with each other; motors for rotational movement together with each other; a drive part connected to;
a composite hammer having an outer driven part and an inner driven part having an impact jaw engageable with the impact jaw of the anvil;
the outer driven part and the inner driven part of the hammer are connected to each other and to the hammer drive part for coupled rotational movement and are disposed between the hammer drive part and the hammer outer driven part; a flyweight arranged with respect to the impact jaw of the hammer; movable axially with respect to the drive part of the hammer and the anvil under the action of a return spring mounted between an actuation spring and a driven part of the hammer; In an impact wrench comprising a spring-loaded locking member and a camming surface of said anvil and a device for pre-acting on said hammer and said anvil before engagement of said impact jaws, said spring-loaded locking member 5 is Located in the inner driven part 14 of the hammer in the axial space between the impact jaws 4 and 3 of the hammer and anvil 2, a counterbore 11 is located in the inner driven part 1 of the hammer.
4 and the actuation spring 29 or 52 mounted between the inner driven part 14 of the hammer and the anvil 2;
An impact wrench, characterized in that it is provided in the axial bore 10 of said anvil 2 for receiving. 2. Impact wrench according to claim 1, characterized in that the inner driven part 14 of the hammer is essentially a sleeve 14a which is axially movable on an axle 19 arranged in the casing. 3. The inner driven part 14 of the hammer has an axially extending projection 34 facing the motor, and the outer driven part 13 of the hammer has an axially extending projection 34 of the inner driven part 14 of the hammer. The impact wrench according to claim 2, characterized in that it has a recess 33 for receiving the portion 34. 4. The inner driven part 14 of the hammer is essentially an axially movable intermediate shaft 14b with one end journaled in the axial bore 10 of the anvil 2. The impact wrench described in scope 1. 5. The spring-loaded locking member 5 has a bevel 37 facing the anvil 2 capable of engaging a cam surface of the anvil cut into the impact jaw 3. impact wrench.