WO2008018221A1

WO2008018221A1 - Power ratchet wrench

Info

Publication number: WO2008018221A1
Application number: PCT/JP2007/060424
Authority: WO
Inventors: Tatsuya Amami
Original assignee: Kuken Co., Ltd.
Priority date: 2006-08-07
Filing date: 2007-05-22
Publication date: 2008-02-14
Also published as: JP2008036772A; TW200815163A

Abstract

A power ratchet wrench in which conventional bearings and a crankshaft can be used and with which bolts and nuts can be manually tightened and loosened without applying an excessive force to the crankshaft to break a crank pin. This ratchet wrench is characterized by comprising ratchet yoke over-rotation suppressing means (44, 45, 46a). The over-rotation suppressing means come to contact with a part of a ratchet yoke (6a) when the ratchet yoke (6a) rotates to the maximum swing position by power driving or to the position in which the angle is less than the over-rotation angle at which the crank pin is broken by rotating only one more turn from the maximum swing position with a torque applied to the output shaft thereby to suppress the further over-rotation of the ratchet yoke (6a).

Description

Specification

Powered ratchet trench

Technical field

TECHNICAL FIELD [0001] The present invention relates to a power-type ratchet trench.

Background art

[0002] As a device that can easily tighten or loosen a bolt or nut, there is a power type ratchet wrench driven by air (see, for example, Patent Documents 1 and 2).

For example, as shown in FIG. 14, the power type ratchet wrench 100 includes a crankshaft 110, a ratchet yoke 120, a ratchet pole 130, and a ratchet shank 140.

[0003] The crankshaft 110 includes a crankpin 112 at a position eccentric to a crankshaft 111 that is rotated by driving an air motor or an electric motor (not shown).

The ratchet yoke 120 is supported in a ratchet nosing 150 so as to be rotatable about the same center axis as the later-described ratchet shaft 140, and a crank pin 112 is connected via a drive bushing 115. As the crank pin 112 rotates eccentrically, it reciprocates within a predetermined rotation angle.

[0004] The ratchet pole 130 is swingably supported in the notch groove 141 of the ratchet shaft 140 via the shaft pin 131, and teeth 132 that mesh with the internal gear 121 of the ratchet yoke 120 are provided on both sides. It has been.

In the case of the ratchet pole 130 shown in FIG. 14, when the ratchet yoke 120 rotates in the direction of arrow A, one tooth 132 meshes with the internal gear 121 of the ratchet yoke 120 so that the ratchet yoke 120 is integrated with the ratchet yoke 120. Cheetshyank 140

When the ratchet yoke 120 is rotated in the direction of arrow B by rotating in the direction of rotation of the wheel 120, the teeth 132 slip and do not mesh with the internal gear 121 of the ratchet yoke 120, and transmit the torque of the ratchet yoke 120 to the ratchet yoke 140. I ca n’t do it! RU

[0006] On the other hand, if the rotation direction switching lever 160 is switched, the ratchet pole 130 will move to the other tooth 13 of the ratchet pole 130 when the ratchet yoke 120 rotates in the arrow B direction. When 2 is meshed with the internal gear 121 of the ratchet yoke 120 and the ratchet yoke 120 is rotated in the direction of rotation of the ratchet yoke 120 together with the ratchet yoke 120, and the ratchet yoke 120 rotates in the direction of arrow A, the teeth 132 slips and does not mesh with the internal gear 121 of the ratchet yoke 120, and the rotational force of the ratchet yoke 120 cannot be transmitted to the ratchet shaft 140!

That is, the ratchet 140 rotates only in one direction of force in the direction of the arrow A or the direction of the arrow B when the air motor or the electric motor is driven by switching the rotation direction switching lever 160. Bolts and nuts can be tightened or loosened by means of sockets (not shown) attached to Tsutsuyan 140.

[0007] By the way, in the case of the power type ratchet wrench 100 as described above, the rotational torque due to the motor driving of the ratchet sunk 140 is not so large. After tightening using the driving force of the motor, it may be necessary to hold the handle part of the power-operated ratchet trench 100 and tighten it further manually.

[0008] That is, when a screw is tightened using a power-type ratchet wrench, if the motor is driven by operating the operation lever of the ratchet wrench 100, the output shaft of the ratchet shaft 140 is rotated by the power. Screws are tightened. Then, the torque required to rotate the screw side gradually increases, and at a certain point in time, the torque on the screw side exceeds the torque of the output shaft by the motor driving force, and the rotation of the output shaft stops. The torque of the output shaft at that time is called the stall torque, and the screw cannot be tightened any more with power drive. In the case of an air-driven ratchet trench with a square drive output shaft size of 9.5 mm and a total length of about 170 mm, the air pressure is 0.6 MPa (Pe), depending on the design specifications of the individual trench trench. Although it is different, the stall torque is about 15 N'm. On the other hand, the normal tightening torque when tightening bolts of strength category 5.8 with M10 using this air-driven ratchet wrench is usually 30 to 40 N'm depending on the design. Therefore, after tightening to the stall torque by power using the air drive type ratchet wrench, it is necessary to further tighten to the predetermined tightening torque by human power. [0009] Also, when loosening bolts and nuts, first loosen the bolts and nuts that were tightly tightened by hand by holding the handle part of the power-type ratchet trench 100, and then reduce the driving force of the air motor or electric motor. In some cases, it may be further loosened.

[0010] That is, when the power type ratchet trench 100 is used to perform the final tightening or the first loosening manually, in any case, it is necessary to apply a torque larger than the stall torque to the output shaft. When a torque larger than the stall torque is applied to the output shaft, the ratchet yoke 120 is in an over-rotation state that swings further outward than the predetermined maximum swing position during power driving, and the crank pin 112 of the crankshaft 110 has a ratchet All of the force corresponding to the torque applied to the output shaft of the shank 140 is applied. For this reason, the crankshaft 110 is designed so that the crank pin 112 does not break when the torque required for the initial loosening is only applied to the output shaft when the crankshaft 110 is tightened with a predetermined tightening torque. Te!

However, depending on the operator, tightening with excessive torque may cause the ratchet yoke 120 to over-rotate and the crank pin 112 may be damaged by excessive force, or may be damaged when loosened. Due to seizure and rusting, a very large torque is required to loosen the screw, and the ratchet yoke 120 may over-rotate and the crank pin 112 may be subjected to a very large force and break.

[0011] Thus, if the bearing is made larger and the crank pin is thicker, the above-mentioned problems can be solved, but the tip portion of the power type trench trench becomes larger in both width and thickness. However, there is a problem that the handling becomes heavy and the workability in a narrow place is deteriorated.

On the other hand, in order to avoid damaging the conventional power lathe trench 100, it is possible to switch to a manual tool such as a wrench or eyeglass wrench and perform the final tightening work or the first loosening work. And there is a problem that the number of tools increases

[0012] Patent Document 1: Japanese Utility Model Publication No. 6-39896

Patent Document 2: Japanese Patent Laid-Open No. 2004-106161

Disclosure of the invention

[0013] In view of the above circumstances, the present invention can use conventional bearings and crankshafts. An object of the present invention is to provide a power driven trench that can tighten or loosen bolts and nuts manually without applying a force to the crankshaft to break the crankpin.

[0014] In order to achieve the above object, the power ratchet wrench according to the present invention is configured so that the ratchet yoke engaged with the crankpin is rotated at a predetermined rotation angle by the rotation of the crankshaft having the crankpin. In a power type ratchet trench in which the output shaft of the ratchet shaft rotates by reciprocatingly swinging around the rotating shaft, the ratchet yoke is driven by a torque driven by the torque applied to the output shaft; Ratchet yoke over-rotation suppression means that abuts against a portion of the ratchet yoke when it rotates to a position below the over-rotation angle at which the crank pin breaks only by one over-rotation from the position, and prevents further over-rotation of the ratchet yoke It is characterized by having.

[0015] The over-rotation suppression means only needs to prevent a part of the ratchet yoke from abutting at an over-rotation position below the over-rotation angle at which the crank pin breaks in one over-rotation, and to prevent further over-rotation. It is preferable to install it at a position where it abuts a part of the ratchet yoke in an over-rotation state when the output shaft has a torque of 40% or less of the torque at which the crank pin breaks due to over-rotation. In most cases, it is most preferable to contact, but in practice, the maximum vibration due to power drive considering the variation in dimensions within the tolerances of each part and play when assembled; the ratchet yoke at a position slightly over-rotated from standing It is preferable that it is provided so as to abut against a part of the surface and to prevent further over-rotation.

Further, the power type ratchet wrench of the present invention may include a tightening torque adjusting mechanism.

[0016] The power type ratchet wrench according to the present invention is configured as described above. Therefore, the crankshaft of the crankshaft can be obtained without increasing the bearing length or increasing the crankpin of the crankshaft. Using a power ratchet wrench that does not break the crank pin, the bolts and nuts can be manually tightened or loosened manually.

Therefore, it is not necessary to prepare a separate manual tool such as a wrench or eyeglass wrench, which improves workability. And make the tip of the power type trench trench compact This makes it possible to work in a confined area as well as improve the operability by reducing the weight.

[0017] Further, the over-rotation suppression means abuts against a part of the ratchet yoke in an over-rotation state when a torque of 40% or less of the torque at which the crank pin breaks in one over-rotation is applied to the output shaft. If it is provided at a certain position, the accident that the crank pin breaks due to metal fatigue due to repeated use can be reduced. In addition, it can be used for a long period of time because the damage to the crankshaft and the bearings that hold it is reduced.

Furthermore, if the structure is equipped with a tightening torque adjustment mechanism, the bolts and nuts can be securely tightened with an appropriate tightening torque, and screw damage due to excessive tightening can be prevented.

Brief Description of Drawings

FIG. 1 is a perspective view showing a first embodiment of a power latch ratchet wrench according to the present invention.

2 is a front cross-sectional view of the power type ratchet trench of FIG.

3 is a cross-sectional plan view of a ratchet portion for explaining the movement of the ratchet yoke during air drive of the power ratchet trench of FIG. 1.

4 is a cross-sectional plan view of the ratchet portion illustrating the state of the ratchet yoke during manual screw tightening using the power ratchet wrench of FIG. 1.

FIG. 5 is a cross-sectional plan view of the ratchet portion illustrating the state of the ratchet yoke when the screws are loosened by human power using the power ratchet wrench of FIG. 1.

FIG. 6 is a second embodiment of a power ratchet wrench according to the present invention, illustrating a state of a ratchet yoke for explaining a state of a ratchet yoke during manual screw tightening using the power ratchet wrench. FIG.

FIG. 7 is a third embodiment of a power ratchet wrench according to the present invention, and illustrates a state of a ratchet yoke for explaining a state of a ratchet yoke during manual screw tightening using the power ratchet wrench. FIG.

FIG. 8 shows a fourth embodiment of a power ratchet wrench that is useful for the present invention, and is a partially cutaway plane for explaining the movement of the ratchet yoke during air drive of the power ratchet wrench. It is sectional drawing.

FIG. 9 is a partially cutaway plan sectional view illustrating the state of the ratchet yoke during screw tightening with human power until the predetermined tightening torque of the power ratchet trench of FIG. 8 is reached, and the movement of the tightening torque adjusting mechanism. .

[FIG. 10] A partially cutaway plan sectional view illustrating the state of the ratchet yoke during screw tightening with human power when the predetermined tightening torque of the power type ratchet trench of FIG. 8 is reached and the movement of the tightening torque adjusting mechanism. is there.

FIG. 11 is a partially cutaway plan sectional view illustrating a state of the ratchet yoke when the screw firmly tightened using the power type ratchet wrench of FIG. 8 is first slightly loosened by human power.

FIG. 12 is a graph showing the relationship between the torque applied to the output shaft of the power ratchet trench used in Example 1, the travel distance of the ratchet yoke, and the over-rotation angle.

FIG. 13 is a graph showing the relationship between the torque applied to the output shaft of the power ratchet trench used in Example 3, the travel distance of the ratchet yoke, and the over-rotation angle.

FIG. 14 is a plan sectional view of a ratchet portion of a conventional power ratchet trench.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.

FIG. 1 to FIG. 5 show a first embodiment of a power driven trench trench according to the present invention.

As shown in FIGS. 1 and 2, the power ratchet wrench la is air-driven and includes a handle portion 2 and a ratchet portion 3a.

As shown in FIG. 2, the handle portion 2 has an air motor 23 that is driven to rotate by compressed air supplied from an air source (not shown) such as an air compressor by operating the operation lever 22 in the cylindrical knowing 21. It is equipped with.

As shown in FIGS. 1 to 3, the ratchet portion 3a includes a ratchet housing 4, a crankshaft 5, a ratchet yoke 6a, a ratchet shaft 7, a ratchet pole 8, and a rotation direction cut. A replacement lever 9 is provided.

The ratchet housing 4 includes a housing main body 41 at one end and an upper holding plate 42 and a lower holding plate 43 facing the other end. [0022] The housing main body 41 has a cylindrical shape, is connected to the cylindrical knowing 21 and incorporates a crankshaft 5 therein.

The upper holding plate 42 is provided with a hole 42a for allowing a knob 91 of a rotation direction switching lever 9 described later to face the outside.

[0023] The lower holding plate 43 is provided with a hole 43a for allowing an output shaft 72 of a later described turbine shaft 7 to face the outside.

Further, the upper holding plate 42 and the lower holding plate 43 are connected to each other at the end on the side of the nosing body 41 via a stopper wall 44 serving as over-rotation suppression means.

The crankshaft 5 includes a crankshaft 51 and a crankpin 52 that is provided eccentrically with respect to the crankshaft 51.

As shown in FIG. 2, the crankshaft 51 is rotatably supported in the housing body 41 via a bearing 53, and the rotational driving force of the air motor 23 is caused by the planetary gear 24 and the gear frame 25. Will be communicated through.

The crankpin 52 faces the upper holding plate 42 and the lower holding plate 43 and is connected to the ratchet yoke 6a via the drive bushing 54.

As shown in FIG. 3, the ratchet yoke 6a has a substantially horseshoe shape. As shown in FIG. 3, a gear hole 61 provided with an internal gear 61a on the inner surface and a substantially semi-cylindrical groove 6 2 into which the drive pusher 54 is fitted. It has.

The drive pusher 54 is fitted in the substantially semi-cylindrical groove 62 so as to be slidable in the axial direction of the substantially semi-cylindrical groove 62, and supports the crank pin 52 so as to be rotatable.

The latch shaft 7 includes a shank body 71 and an output shaft 72.

The shank body 71 has a cylindrical shape that is slightly smaller than the inner diameter of the gear hole 61 of the ratchet yoke 6a. A notch groove 73 is formed on the side wall surface, and a shaft hole 74 whose lower end opens into the notch groove 73 at the center of the upper surface. Is drilled.

The rotation direction switching lever 9 includes a knob 91 and a rotation shaft 92, and the rotation shaft 92 is rotatably fitted in the shaft hole 74.

Further, as shown in FIG. 3, a lever stop 94 biased by a spring 93 is mounted at a position facing the notch groove 73 of the rotating shaft 92. [0029] In the cutout groove 73, a ratchet pole 8 is supported so as to be swingable about a shaft pin 81 as shown in FIG.

As shown in FIG. 3, the ratchet pole 8 is provided with teeth 82 shaped to engage with the internal gear 61a of the ratchet yoke 6a on both sides in the swing direction, and has an arc shape on the wall surface facing the rotary shaft 92. A recessed portion 83 is provided.

[0030] On the inner wall surface of the recess 83, the tip of the lever stop 94 is always urged by the urging force of the spring 93.

The stopper wall 44 is provided so that a gap S is formed between the ratchet yoke 6a and the stopper wall 44 when the ratchet yoke 6a is maximally shaken during the air drive operation. Fig. 3 shows the maximum runout position of the ratchet yoke 6a during the air drive operation with a two-dot chain line. The maximum runout position during the air drive operation is the center of the gear hole 61 of the ratchet yoke 6a and a substantially semi-cylindrical shape. The distance from the center of the groove 62 and the crankpin 5 of the crankshaft 5

2 is determined by the eccentric distance from the crankshaft 51 and the shape of both side surfaces from the rear end portion of the ratchet yoke 6a having a substantially horseshoe shape to the substantially semicircular portion on the front end side.

[0031] Further, the clearance S is such that a part of the over-rotated ratchet yoke 6a abuts against the stopper wall 44 at a position below the over-rotation angle at which the crank pin 52 breaks in one over-rotation.

It is preferable that the size is as small as possible as long as variation in dimensions within the tolerances of each part and play when assembled are allowed.

[0032] Next, the operation of the power type ratchet trench la during air driving will be described in detail.

In this power-type ratchet trench la, the crankshaft 5 rotates about the crankshaft 51 when the operation lever 22 is operated to drive the air motor 23. Therefore, the crank pin 52 of the crankshaft 5 rotates eccentrically around the rotation axis of the crankshaft 51.

When the crankpin 52 rotates eccentrically, the ratchet yoke 6a reciprocates around the central axis of the gear hole 61 of the ratchet yoke 6a within a predetermined rotation angle. Since the gap S described above is provided, the ratchet yoke 6a does not contact the stopper wall 44 even at the maximum swing position.

At this time, if there is a lever stop 94 at the position shown in FIG. When rotating in the X direction, the tooth 82 at one end of the ratchet pole 8 meshes with the internal gear 61a, and the other end face of the ratchet pole 8 presses the bottom of the notch groove 73 of the shank body 71. Rotate in the X direction. On the other hand, when the ratchet yoke 6a rotates in the arrow Y direction, the internal gear 61a and the tooth 82 at one end of the ratchet pole 8 are disengaged, and the ratchet shaft 7 does not rotate. That is, ratchet shelving 7 rotates only in the X direction. Therefore, using a jig (not shown) such as a socket set on the output shaft 72, the bolts and nuts can be tightened (or loosened in the case of reverse screws).

[0034] On the other hand, although not shown, the ratchet pole 8 is moved around the shaft pin 81 so that the rotation direction switching lever 9 is operated and the tooth 82 at the other end is in force against the internal gear 61a. On the contrary, the ratchet 7 rotates only in the arrow Y direction. Therefore, using a jig (not shown) such as a socket set on the output shaft 72, the bolts and nuts can be loosened (tightened in the case of reverse screws).

[0035] Next, a case where bolts and nuts are manually tightened to a predetermined tightening torque using the lattice trench la and a case where the first loosening is performed will be described.

[0036] (Tightening by human power)

After tightening the bolts and nuts to the stall torque by power, release the operation lever 22 and stop the air motor 23. Next, with the jig fitted to the bolt or nut set on the output shaft 72, if you hold the handle part 2 with your hand and try to rotate it in the direction of the arrow X, the handle part 2 will be moved first. The ratchet yoke 6a, which is integrated with the ratchet shaft 7 via the ratchet pole 8, does not reach the torque necessary for the output shaft 72 to turn the screw side, and thus maintains its position. Therefore, the ratchet yoke 6a rotates relatively by the gap S from the predetermined maximum shake position by the driving force. At this time, the ratchet yoke 6a is provided with a force stopper wall 44 that is in an over-rotation state, so that the rear side edge, which is a part of the ratchet yoke 6a, abuts against the stopper wall 44 as shown in FIG. There is no over-rotation. Thereafter, when the handle portion 2 is further rotated, the ratchet yoke 6a is also rotated integrally with the handle portion 2 and can be tightened. That is, when tightening by human power, most of the force corresponding to the torque required to rotate the screw is received by the stopper wall 44, The crankpin 52 is not subjected to such a large force that it breaks (in FIG. 4, the crankpin 52 is greatly distorted outward, but it has been exaggerated to make it easier to split the operation. Actual strain is small)

Therefore, with this power driven trench trench la, the bolts and nuts are tightened to the torque torque by air drive, and the crankshaft part is not damaged even if it is not changed to a manual tool such as a spanner or eyeglass wrench. Tightening up to the specified torque can be done manually.

[0037] (Loosening by human power)

When the rotation direction switching lever 9 is operated, as shown in FIG. 5, the tooth 82 at the other end meshes with the internal gear 61a, the ratchet shaft 7 rotates only in the direction of the arrow Y, and the air motor 23 Is stopped, and the jig set on the output shaft 72 is fitted to the bolt and nut, and the handle part 2 is held by hand and rotated in the direction of arrow Y. At this time, first, the handle portion 2 is rotated first, and the ratchet yoke 6a maintains the position as it is, so that the ratchet yoke 6a rotates relatively by the gap S from the maximum deflection position by power drive. So it will be over-rotated. However, since the stopper wall 44 is provided, the rear side edge of the ratchet yoke 6a abuts against the stopper wall 44 as shown in FIG. Thereafter, when the handle portion 2 is further rotated, the ratchet yoke 6a is also rotated integrally with the handle portion 2, and the bolts and nuts can be first loosened. In other words, when loosening by human power, most of the force corresponding to the torque for rotating the screw is received by the stopper wall 44, so that a large force that breaks the crank pin 52 is not applied.

Therefore, by using this power type ratchet trench la, the initial loosening of bolts and nuts and the subsequent loosening of bolts and nuts by air drive can be performed continuously without breaking the crank pin 52 by human power. .

FIG. 6 shows a second embodiment of a power-type ratchet trench useful for the present invention.

As shown in FIG. 6, this power type ratchet trench lb is not provided with a stopper wall 44, and a long hole 63 is formed on the tip side of the ratchet yoke 6b. Except for the insertion of a pin 45 as an over-rotation suppression means fixed to the holding plate 42 and the lower holding plate 43, it is the same as the above-described power-type ratchet trench la.

[0039] That is, the power ratchet trench lb has an over-rotation of the ratchet yoke 6b in which the pin 45 receives the side wall surface of the long hole 63 and the crank pin 52 breaks or the bearing 53 is damaged early. Is suppressed.

[0040] Fig. 7 shows a third embodiment of a power-type ratchet trench that is useful for the present invention.

As shown in FIG. 7, this power type ratchet trench lc is not provided with the stopper wall 44, but is provided with a notch groove 64 on the tip surface of the ratchet yoke 6c, and the tip portions of the upper holding plate 42 and the lower holding plate 43. Except that a wall 46 is provided along the edges of the upper holding plate 42 and the lower holding plate 43, and a protrusion 46a is provided on the wall 46 as an over-rotation suppressing means facing the notch groove 64. It is the same as the above-mentioned power-type ratchet trench la.

[0041] That is, the power ratchet trench lc has a notch 64 in the protrusion 46a even if the ratchet yoke 6c tries to overrotate such that the crank pin 52 breaks or the bearing 53 is damaged early. The side wall surface is received and over-rotation is suppressed.

[0042] Figs. 8 to 11 show a fourth embodiment of a power-type ratchet trench that is useful in the present invention.

As shown in FIGS. 8 to 11, the power type ratchet trench Id includes a ratchet portion 3d and a handle portion 2 similar to the power type ratchet trench la.

[0043] The ratchet portion 3d has a protective tube portion 47 having one end fixed to the casing of the handle portion 2.

The protective tube portion 47 surrounds the crankshaft 51 of the crankshaft 5 and a transmission shaft 57 that transmits a driving force of an air motor (not shown) to the crankshaft 51.

[0044] The ratchet yoke 6a and the ratchet yoke 6a side of the protective tube portion 47 are surrounded by the housing portion 4d.

The winging portion 4d is provided with a ratchet and winging portion 48 and a sheath-like portion 49.

The ratchet housing portion 48 includes an upper protective plate (not shown) and a lower protective plate 48a. The upper protection plate and the lower protection plate 48a are connected to each other at their end portions on the side of the sheath-like portion 49 via stopper walls 48b as over-rotation suppression means.

The sheath-like portion 49 includes slits 49b on both sides of which the protective tube portion 47 can be projected and retracted, except for the tubular portion 49a at the end on the handle portion 2 side.

The tubular portion 49a is provided with a notch recess 49c at the top and bottom of the tube end (not shown in the figure), and a disk-like projection 49d is provided in the screw tightening direction of each notch recess 49c. The inner wall surface 49e of the 49 tubular portion 49a is configured to abut against the outer wall surface 47b of the protective tube portion 47 on the screw loosening direction side in a state where a torque adjusting mechanism described later does not operate.

A tightening torque adjusting mechanism 10 is provided between the sheath-like portion 49 and the handle portion 2. The tightening torque adjusting mechanism 10 includes a sliding body 11, an adjusting coil spring 12, and a flanged tube 13. And an adjusting nut 14.

[0047] The sliding body 11 is provided with a flange portion 11a at one end of the tubular body ib, and is externally fitted to the protective tube portion 47 so as to slide, and a notch recess 49c is formed at the end of the flange portion 11a on the side of the sheath-like portion 49. Rolls that fit into

1 lc is provided rotatably.

The adjustment coil spring 12 has an inner diameter larger than that of the tubular body l ib of the sliding body 11, is substantially the same as or slightly smaller than the flange portion 1 la, has an outer diameter, and one end is externally fitted to the tubular body 1 lb. RU

[0048] The flanged tube 13 is provided with a flange 13a having a diameter slightly larger than the outer diameter of the adjustment coil spring 12 at one end of a tube portion 13b having an outer diameter smaller than the inner diameter of the adjustment coil spring 12. 13b is slidably fitted on the protective tube 47 in a state where it enters the adjustment coil spring 12.

The adjusting nut 14 is screwed into a male threaded portion 47a provided on the handle 2 side end of the protective tube portion 47 so that the urging force of the adjusting coil spring 12 against the flange portion 11a can be adjusted by unfastening. Become.

[0049] It should be noted that the other configuration of the power-type ratchet trench Id is the same as that of the power-type ratchet trench la. [0050] This power type ratchet trench Id is as described above, and during operation by air drive, as shown in Fig. 8, the ratchet yoke 6a rotates at a predetermined rotation angle at the maximum deflection position by power drive. A gap S is formed between the stopper wall 48b and the power lathe trench lat la, similar to the power lathe trench lat.

By switching the rotation direction switching lever 9, the bolt can be tightened and loosened by air drive.

[0051] In addition, when tightening by human power, in the same manner as the above-described power-type ratchet trench la, with the air motor stopped, a jig fitted to a bolt or nut is set on the output shaft. When the handle 2 is held in the hand and is rotated in the direction of the arrow X, the handle 2 is first rotated first, and the ratchet yoke 6a is maintained in its original position. Since it rotates relative to the position by the gap S, it will be over-rotated. However, since the stopper wall 48b is provided, the rear side edge of the ratchet yoke 6a abuts against the stopper wall 48b as shown in FIG.

There is nothing to do. Thereafter, when the handle portion 2 is further rotated, the ratchet yoke 6a is also rotated integrally with the handle portion 2 and can be tightened. When the tightening torque reaches a predetermined value, the tightening torque adjusting mechanism 10 operates as shown in FIG. In other words, the roller 11c fitted into the notch recess 49c moves over the protrusion 49d while retreating the sliding body 11 toward the handle 2 side against the urging force of the adjustment coil spring 12, and engages with the notch recess 49c. The match is released. That is, it can be seen that the tightening with the predetermined tightening torque has been completed.

[0052] On the other hand, when loosening by manpower, the jig set on the output shaft is fitted to the bolt and nut while the air motor is stopped, as in the case of the power type ratchet wrench la. Hold part 2 by hand and rotate it in the direction of arrow Y. At this time, first, the handle portion 2 rotates first, and the ratchet yoke 6a maintains the position as it is, so the ratchet yoke 6a rotates relatively by the gap S from the maximum swing position of the power drive. Over-rotation will occur. However, since stopper wall 48b is provided, as shown in FIG. The rear side edge of the toe yoke 6a abuts against the stopper wall 48b and does not over-rotate further. Thereafter, when the handle portion 2 is further rotated, the ratchet yoke 6a is also rotated integrally with the handle portion 2, and the bolts and nuts can be first loosened.

When turning the power driven trench trench Id in the direction of loosening the screw, the outer wall surface 47b of the protective tube portion 47 directly exerts a force on the inner wall surface 49e of the tubular portion 49a. Will not work.

In other words, the power type ratchet trench Id can be tightened with a predetermined tightening torque by operating the tightening torque adjusting mechanism 10 for tightening the screws. On the other hand, since the screw loosening is not related to the torque set by the tightening torque adjustment mechanism 10, it is possible to loosen a screw that is tightly tightened, and most of the force corresponding to the torque required to loosen it. Can be held by the stopper wall 48b, so that the screw can be loosened without breaking the crank pin 52.

[0053] As described above, this power type ratchet wrench Id has a protective tube portion 47 surrounding the crankshaft 5, and this protective tube portion 47 further includes a ratchet housing portion 48. Therefore, the ratchet housing part 48 tends to be thicker than the above-mentioned power type ratchet trench la ~: Lc. However, if the present invention is applied, the stopper wall 48b can receive most of the force corresponding to the torque even when tightening or loosening the screw with a large torque. It is possible to make it thinner. By making the crankpin 52 thinner than usual, the drive bushing 54 can also be reduced in size, and the protective tube part 47 and the ratchet housing part 48 are made thinner in the axial direction of the ratchet shank 7 accordingly. can do. Therefore, light weight can be achieved and operability is improved, and even when there is an obstacle above the bolt head, a thin ratchet housing part 48 can be inserted into the gap to tighten and loosen the bolt. Is possible.

In addition, this power type ratchet trench Id adjusts the urging force of the adjustment coil spring 12 by untightening the adjustment nut 14, and can securely tighten the bolts and nuts to be tightened with appropriate torque. Screw damage can be prevented.

[0054] Specific examples of the present invention are described in detail below.

[Example 1] After tightening the bolts up to the stall torque using a ratchet trench made by Kuken Co., Ltd. (model number KR-183, crank pin diameter φ 7.5 mm, maximum torque at power drive 30 N'm), power the ratchet yoke Maximum vibration during driving; the standing state force gradually increased the torque on the output shaft of the ratchet shaft, and when the torque at which the crankpin was broken was determined, the crankpin was broken at a torque of 380 mm.

In addition, the rear edge of the ratchet yoke was examined as to how much it moved in the direction perpendicular to the axial direction of the handle section as a result of the maximum vibration during the power drive of the ratchet yoke as the torque increased. This is shown in Fig. 12 in comparison with the converted value of the over-rotation angle of the ratchet yoke that also converted the measured travel distance force.

As shown in Fig. 12, the travel distance of the trailing edge of the ratchet yoke with the maximum deflection position force during power driving of the ratchet yoke when the crankpin is broken is 0.7 mm (the overrotation angle of the ratchet yoke is about 1. 44 °).

[0056] (Example 2)

The state force when the ratchet yoke of the ratchet trench used in Example 1 is at the maximum deflection position during power drive is also 150 Nm (the torque at which the crankpin breaks due to one over rotation 380 N ' When torque of 40% of m) was repeatedly applied, the crank pin broke after 3000 times. At this time, the movement distance of the rear end side edge of the ratchet yoke was 0.42 mm (the ratchet yoke over-rotation angle was about 0.86 °).

On the other hand, in the case of the ratchet trench used in Example 1, considering the variation in dimensions within the tolerances of each part and the play when assembled, the maximum deflection position during power drive of the ratchet yoke is designed. The gap between the stopper wall and the stopper wall was about 0.3 mm.

[0057] Therefore, when the stopper wall is provided in the lattice trench used in Example 1 so that the gap is 0.3 mm, the ratchet yoke has a torque of 105 N'm as shown in FIG. The maximum swing is the same as that applied to the shaft of the shaft. ^ When the rotor is over-rotated from the standing position, the trailing edge of the ratchet yoke is received by the stopper wall.

That is, when a torque larger than 105 N'm is applied to the output shaft of the ratchet shaft, a force corresponding to a torque exceeding 105 N * m is received by the stopper wall 44, and the crank pin has a torque of 105 N 'm. Only the power according to will be added. Therefore, since the force corresponding to the torque of 105Ν · πι is 2/3 of the force corresponding to the torque of 150N'm, the life of the crankpin depends on the torque of 150N'm from the relationship of S-— curve. It is easily guessed that it is much improved compared to 3000 times when the power is repeatedly applied.

[Example 3]

After using a ratchet trench (model number KR-133A, crank pin diameter φ5.5mm, maximum torque 20N'm during power drive) made by Kuken Co., Ltd., tighten the bolt to the stall torque and then power the ratchet yoke. The maximum vibration during driving; even when standing, the torque was gradually applied to the output shaft of the ratchet shank, and the crankpin breaking torque was determined. The crankpin was broken at a torque of 140 N'm.

In addition, the rear edge of the ratchet yoke was examined to see how far it moved in the direction perpendicular to the axial direction of the handle section as a result of the maximum vibration during the power drive of the ratchet yoke as torque increased. Fig. 13 compares this with the converted value of the over-rotation angle of the ratchet yoke that also converted the measured travel distance force.

[0059] As shown in Fig. 13, the movement distance of the trailing edge of the ratchet yoke with the maximum deflection position force during power driving of the ratchet yoke when the crank pin is broken is 0.28mm (overshoot angle of the ratchet yoke) About 0.77 °).

In addition, in the case of the ratchet trench used in Example 3, considering the variation in dimensions within the tolerances of each part and the play at the time of setting up, the maximum deflection position during power drive of the ratchet yoke is designed. The gap between the stopper wall and the stopper wall was about 0.2 mm.

[0060] The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, driving may be performed by a force electric motor that is designed to be driven by an air motor.

Claims

The scope of the claims

[1] The rotation of the crankshaft having the crankpin causes the ratchet yoke engaged with the crankpin to reciprocate around the rotation axis of the ratchet yoke at a predetermined rotation angle, and the output shaft of the ratchet shaft rotates. In the power ratchet trench,

When the ratchet yoke rotates to a position below the over-rotation angle at which the crank pin breaks only after the maximum swing position by power drive or the maximum swing due to the torque applied to the output shaft; And a ratchet yoke over-rotation restraining means that abuts against a part of the ratchet yoke and prevents further over-rotation of the ratchet yoke.

[2] The power type ratchet wrench according to claim 1, further comprising a tightening torque adjusting mechanism!