JPH03117568A - Power wrench - Google Patents

Abstract

PURPOSE: To simplify the structure of a power wrench by transmitting the output of a first gear step to an output shaft through a first driving branch part having a first coupling and also through a second driving branch part having a second coupling and a second gear step to the output shaft. CONSTITUTION: When screw-in moment is low, the output of a first gear step 21' is directly transmitted to an output shaft 38, so that the output shaft 38 is driven at a relatively high speed. At this time, the transmission of power through the other driving branch part is intercepted. When the load torque exceeds a specified limit value, a common movable coupling 36 occupies the other position. Thus, the torque is transmitted through a second gear step 26' at a low speed and with large torque.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to power wrenches.

BACKGROUND OF THE INVENTION It is known to use power wrenches, which operate using electrical power or pressurized fluid, to tighten screws or bolts. When driving a screw into a tapped hole, the screw initially provides only a low resistance to the power wrench, so it is possible to turn the screw at a high speed and with low torque. If the resistance provided by the screw increases significantly, the power wrench must be driven at a lower speed and with greater torque. When loosening a screw as opposed to tightening it, it is necessary to first apply a large torque to the screw, and then operate the power wrench at a lower torque and faster speed.

Motor-driven power wrenches are also known which are configured to manually or dynamically change the speed and torque associated with the power wrench depending on the screwing moment. For power wrenches with an automatic switching device driven by a hydraulic motor, the power wrench will switch to the high torque side when the working pressure is measured and it is determined that the working pressure exceeds a predetermined limit. Can be switched. In the case of power wrenches driven by electric motors, the screwing moment is automatically switched depending on the current being consumed.

Power wrenches of the type equipped with ratchet couplings are also known. When the screwing moment is low, the ratchet coupling is in the engaged state and the output shaft has a ratchet force.

Rotate at a fast speed through bling. When the load torque exceeds a predetermined limit, the ratchet coupling disengages and the output shaft engages the shaft rotating at a lower speed.

The disadvantage of this arrangement is that during operation at high torques, the ratchet coupling is continuously subjected to strong mechanical stresses and continuously generates shocks.

In the case of known motor-driven power wrenches, the fast rotation of the motor's output shaft can be slowed down through a conventionally known mechanism consisting of a plurality of gears supported laterally offset from each other. is necessary. A relatively large space is required to arrange these gears, and the gears are also heavy.

(German Published Patent Box 37 20 633 Δ1)
In the case of a known power wrench of the type described in the features of claim 1, three i1 star gears are arranged in line between the drive shaft and the output shaft. The annular wheels of the planetary gears on the input and output sides are
It is axially movable and rotatably supported within the power wrench casing.

The annular wheel of the planetary gear on the input side can be fixedly connected to the planetary carrier in a first position and fixedly connected to the casing by means of a coupling in a second position. When the screwing moment is low, the coupling is in the first position and the annular wheel of the planetary gear on the input side is connected in frictional engagement with the planetary carrier, resulting in a relatively fast same rotates with the planetary carrier at speed.

When the screwing moment exceeds a predetermined value, a spring-loaded cam mechanism moves the coupling to the second position. This locks the annular wheel of the planetary gear on the input side, preventing it from rotating inside the casing and releasing the clamping force acting between the annular wheel and the planet carrier. . Thus, the planet carrier rotates at a relatively low speed. Furthermore, the power wrench is equipped with a second coupling, called a slip clutch, which interrupts the transmission of torque when the screwing moment exceeds a maximum value.

A disadvantage of the above-mentioned known power wrenches is that the switching mechanism for switching the transmission ratio of the gears on the input side is complex. The annular wheel of the planetary gear is axially movable and rotatably supported within the casing. In addition, the annular wheel and the casing are connected to each other by a complex mechanism so that the annular wheel of the planetary gear on the input side can be fixedly connected to the casing or fixedly connected to the planetary carrier. Must be able to move relatively. A coupling, which is designed to fixedly connect the annular wheel of the planet gear on the input side to the planet carrier or casing, cooperates with the planet gear to form a component unit. Therefore, the switching mechanism has a complicated structure. Furthermore, the axially movable parts must be manufactured within narrow tolerances. As a result, the axially movable portion may become jammed in the guide, potentially interfering with the operation of the switching mechanism.

(Problem to be Solved by the Invention) An object of the present invention is to provide a power wrench that has a simple structure and operates without failure.

According to the invention, the power wrench is constructed such that the second gear stage is contained in one of the two separate drive branches. The torque is transmitted by two successively rotating separate drive branches with different speed transmission ratios. Depending on the screwing moment, one or the other of the drive branches is selectively used to drive the output shaft at high or low speed.

(Operation and Effect) Switching is performed via two couplings arranged at the drive branch.

a movable coupling member common to both couplings is in engagement with one of the two couplings;
The other is displaced so that it is disengaged.

The speed of the drive shaft of the transmission mechanism is always reduced via the first gear, regardless of the magnitude of the screwing moment of the power wrench. When the screwing moment (load moment) is low, the output of the first gear stage is directly transmitted to the output shaft, so that the output shaft is driven at a relatively high speed. At this time, power transmission via the other drive branch is interrupted.

When the load torque exceeds a predetermined limit value, the common movable turnpull assumes the other position. (Thus, torque transmission takes place via the second gear stage at low speed and high torque. Switching couplings or doubles designed as overload couplings without external control) - Switching takes place via a coupling; no idling occurs, since the coupling member is always connected to one of the drive branches;

Since the reduction ratio of the gears is constant and changing the reduction ratio of at least one of the two gears does not require a complicated control mechanism that is prone to failures, it is easy to configure the gears. It is.

Because planetary gears are used, the torque-dependent coupling can be constructed in a compact tubular construction and can also be constructed in a lightweight construction.

Advantageously, a guide curve is formed on the output shaft and the guide element of the turnip pull member is arranged to engage with the guide curve. When the load torque exceeds a predetermined limit value, the common turnpull member moves axially against the displacement. The coupling member can be displaced using a spring device or by applying hydraulic pressure. In order to adjust the magnitude of the load moment at which the switching takes place, it is advantageous to adjust the displacement via an external control device.

It is advantageous to design one of the two couplings as a ball bearing. For ball-cube pulls, a movable coupling member and a coupling body are connected to the planetary carrier of the first planetary gear through a spring-forced ball that is pressed into a non-circular path. Coupling takes place between. Such a ball-cube spring forms a sliding coupling configured to permit movement of the force-knob ring body and force-knob ring member relative to each other.

In order to reduce the loads acting on the coupling elements when such relative movements occur and to make better use of the drive energy, a free spacer is provided adjacent to the engagement path containing the recess of the ball-cube-pring. A suitable idling path is provided. When the second drive branch is engaged, the idle path receives the ball.

Advantageously, the planet carrier of the first planetary gear extends coaxially with respect to the drive shaft and has an output shaft with a projection extending beyond the second gear stage. The output shaft carries the sun gear of the second planetary gear, while the projection is connected to the coupling body of the first coupling. Since the two gear stages and the coupling are arranged coaxially, the switchable gear can be configured compactly.

(Examples) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, which illustrate examples of the present invention.

FIG. 1 is a side view illustrating the entire configuration of a power wrench according to the present invention. This power wrench is hand
It is designed like a drill and is equipped with a drive part 1 which encloses a rotary motor (not shown). The rotary motor is operated by pushing an operating lever 2-. The drive part 1 is housed in a separate casing enclosing the handle member 3. Transmission gear system V that operates according to load torque! ! , 4 are attached to the drive l, and the casing 5 of the transmission gear 4 is rotatably supported with respect to the casing of the drive l. Therefore, the drive portion 1 and the knob 3 can be rotated to an appropriate screwed-in position. The transmission gearing 4, which operates in dependence on the load torque, comprises a second planetary gearing, which is mounted on the front part 6 of the casing 5 of the power wrench. A head 7 is fixed to the output shaft of the planetary gearing 4 so that a socket can be fixed to the head 7 for turning the screw. The front part 6 of the casing 5 is provided with a compartment 8 contoured to secure a support (not shown), which compartment 8 is connected to the front part 6 of the casing 5 and thus
The power wrench is rotated by turning the longitudinal shaft by bringing the casing 5 of the transmission gear device 4 connected to the front part 6 into contact with a fixed contact part extending in the transverse direction. It is designed to prevent

FIG. 2 is a conceptual diagram illustrating the functions of the transmission gear device 4 that operates according to torque. The transmission gear 4 has a first gear stage 21', the output shaft of which is connected to the transmission gear 4 via two individually actuatable drive branches 11 and 12. is configured to drive an output shaft 38 of.

One of the two drive branches 11 and 12 is provided with a second gear stage 26'. The two drive branches 11 and 12 are actuated via couplings 32 and 48, respectively. 2
When one of the two couplings 32 and 48 is engaged, the other is disengaged. Both couplings have a common force, the twining member 36. When the coupling gear 8 disposed outside the second gear stage 26' is engaged, the output shaft 38 of the transmission gear device 4 is moved to the second gear stage 26' when the other coupling 32 is engaged. gear stage 2
Torque is directly transmitted to the output socket 38 without going through
When transmitted to the motor, it is driven with greater torque and lower speed.

FIG. 3 is a cross-sectional view of the transmission gear device 4 configured according to the functional explanatory diagram illustrated in FIG. 2 and operated in response to torque. The casing 5 of the transmission gear 4 is mounted on a ball bearing I so as to be rotatable with respect to the drive l.
8. A drive shaft 19 driven by a rotary motor projects into the casing 5 from the front surface of the casing of the drive unit l. The shaft-like shoulder of the sun gear 20 of the planetary gear 21 forming the first gear stage 21' is connected to the drive shaft 19 and rotates together with it. The shaft-shaped shoulder of the sun gear 20 is supported via bearings 23 and 23' mounted in the housing 5 of the transmission gear 4. The teeth of the sun gear 20 mesh with the teeth of a planetary gear 22 arranged around the sun gear 20. The planetary gear 22 is connected to the output shaft 24 of the first gear stage 21'.
It is supported by a planetary carrier 29 forming a. The planet carrier 29 carries a sun gear 25 of a second planet gear 26 driven by the first planet gear 21, which sun gear 25 forms a second gear stage 26'. The sun gear 25 of the second planetary gear 26 drives the planetary gear 27 . The planetary gear 27 is the first planetary gear 21
Like the planetary gear 22, it meshes with the internal teeth 17 of the casing 5.

The output shaft 24 of the planetary carrier 29 has a shaft-shaped projection 30 which extends coaxially beyond the second planetary gear 26 in the casing 5. The planet carrier 52 of the second planet gear 26 is rotatably supported on the shaft-like projection 30 by ball bearings 51 and 51'. The force/one ring body 31 of the first turnpull 32 is rotatably connected to the shaft-like projection 30 . The coupling body 31 has a plurality of radially extending pocket holes 50 in which the ball catch 33 is disposed. In the situation shown in Figure 3, the ball
Ball 34 of catch 33 engages engagement path 35 of movable coupling member 36. The coupling member 36 is surrounded by a cylindrical projection 37 of the output shaft 38, which is connected to the ball bearing 54.
It is supported on the shaft-like projection 30 via a ball bearing 53 and within the casing 5 via a ball bearing 53.

Two guiding curved surfaces 39 in the shape of triangular openings 40 located opposite each other are formed on the outer peripheral surface of the cylindrical projection 37 . One of the triangular openings 40 is illustrated in the plan view of FIG. 4, as viewed from above. The ends of two bottle-shaped guide elements 41 extend through the opening 40 . When the guide curve 39 is engaged with the guide element 41, the output shaft 38 continuously rotates together with the coupling member 36.

The output shaft 38 is therefore able to rotate slightly relative to the opening 40 forming the guide curve 39 . Each aperture 40 is in the shape of an isosceles triangle, with the apex of the isosceles triangle tapering toward the output shaft 38 (see FIG. 4). The guide element 41 connected to the movable coupling member 36 is
A spring 46 supported by the planet carrier 52 of the second planet gear 26 pushes it in the axial direction toward the vertex of the triangle. In the high speed mode shown in FIGS. 3 and 4, the ball 3 in the ball catch 33 is
4 rolls within the engagement path 35 of the coupling member 36, so the coupling body 31 and the coupling member 36 are engaged with each other.

The triangular opening 40 has a symmetrical shape with respect to the axis of the output shaft 38, and the guide curve 39 has two oblique sides 40a and 40b inclined in opposite directions, the guide element 41 having a symmetrical shape with respect to the axis of the output shaft 38. and 40b. If the load moment of the output shaft 38 exceeds a predetermined limit value, the guide element 41 moves to the triangular guide 3.
9 and slides along the sides 40a and 40b.

This causes the turnip pull member 36 to move toward the drive shaft 19 against the action of the spring 46. In this case, the ball 34 of the ball catch 33 slides from the engagement path 35 of the coupling member 36 into the laterally arranged idle path 47, so that the coupling member 36 is in contact with the coupling body 31. The engaged state will be released.

The planetary carrier 52 of the second planetary gear 26 is provided with a coupling body 55 which cooperates with the movable turnpull member 36 to move the second cup 1
Form the rung 48 and press t.

When the load moment of the output shaft 38 exceeds a predetermined limit value, the movable force knob member 36 moves towards the turnip pull body 55 of the second coupling 48 and the pawl 49 of the second force knob ring 48 ' engages with the pawl 49 of the coupling body 55, and the first coupling 32 is released from the engaged state. Transmission gear device 4
is provided with an axial hole 56 extending through the sun gear 20 of the first planet gear 21, the planet carrier 29 with the shaft-like projection 30, and the output shaft 38. There is.

FIG. 5 illustrates a first coupling 32 comprising a coupling body 31 and a movable coupling member 36. As shown in FIG. The coupling body 31 is provided with a ball catch 33, each of which has a ball catch 33 extending in the radial direction of the coupling body 31.
It includes a spring 60 contained in the throat hole 50 and a ball 34 pushed outward by the spring 60. The ball 34 is adapted to roll in an engagement path 35 provided inside the coupling member 36. The diameter of this engagement path 35 varies in the circumferential direction, and a recess 61 is formed in the coupling member 36 into which the ball 34 enters.

A recess 61 is provided corresponding to each ball 34, and as shown in FIG. 5, the recess 61 is arranged so that all the balls 34 enter the recess 61 at the same time. Due to the action of the spring 60, the ball 34
is held in the recess 61 , the coupling body 31 is engaged with the coupling member 36 and the output shaft 38 is rotated together with the coupling 36 via the guide member 41 . Even when the ball 34 is in sliding contact with the engagement path 35 and is pushed into the pocket hole 50 against the action of the spring 60, the coupling 32 can still slide, resulting in damage to the coupling 32. The degree of safety features that prevent this is high. Further, when switching is performed, it is possible to prevent transmission of impact caused by driving.

FIG. 6 illustrates the idle path 47 adjacent the engagement path 35. The diameter of the idle path 47 is constant and there are no indentations along the inner circumference of the pulling member 36. When the load moment is low, the coupling member 36, which is pressed towards the output shaft 38, resists the force of the spring 46 and
movement toward the coupling body 55 of the coupling 48 , the ball 34 moves from the engagement path 35 to the idle path 47 . In this state, the transmission gear device 4
While the second coupling 48 is rotating, the claws 49 and 49' of the second coupling 48 are engaged with each other, so that the coupling body 31 is not released from the coupling state with the coupling member 36.

The operation of the power wrench constructed as described above and shown in FIGS. 1 to 6 will be explained as follows. When tightening a screw, set the power wrench Hept 7 in the socket connected to the screw you are trying to turn. The drive unit l rotates the drive shaft 19.

As a result, the planetary gear 22 of the first planetary gear 21 is driven.

While the screwing moment is low, the first turnpull 32
is in the engaged state, and the torque is applied to 31 of the first planetary gear 21.
! It is directly transmitted via the i-star carrier 29 to the output shaft 38 of the transmission gear 4 which operates in accordance with the torque. The output shaft 38 drives a third downstream planetary gear in the front part 6 of the casing 5, which drives the head 7 at a relatively high speed and low torque. If the load moment exceeds a predetermined limit value, the coupling member 36 common to the two couplings 32 and 48 moves;
The first coupling 32 is disengaged. At the same time, the second coupling 48 becomes engaged. Second
The planetary gear 26 of the second planetary gear 3 engages with the second planetary gear 3!
Torque is transmitted by the engagement of the star carrier 52 with the output shaft 38 of the transmission gearing 4 via the force coupling member 36 .

Since the rotation of the planetary carrier 29 of the first planetary gear 21 is slowed down by meshing with the second downstream planetary gear 26, the power wrench helmet 7 is transmitted through the output shaft 38 at a slow but large speed. Driven by torque. This drive with high torque and low speed continues until the screw is tightened. During this time, there is no switching between high speed and low speed.

FIG. 7 is a conceptual diagram illustrating the function of a transmission gear device constructed according to a second embodiment of the present invention that operates in response to torque. Similar to the transmission gear device of the first embodiment, the second
The transmission gear system of the embodiment also includes two planetary gears 21 and 26 and two couplings 32 and 48. The only difference between the two transmission gears is that the second coupling 48 of the transmission gear of the second embodiment is replaced by the second planetary gear 21.
This means that it is installed on the inside and not on the outside.

FIG. 8 is a cross-sectional view of a transmission gear device constructed according to the second embodiment. A drive shaft 19 projecting from the drive part 1 carries a sun gear 20 of a first planetary gear 21 . The external teeth of the sun gear 20 are the planetary carrier 29
It meshes with the internal teeth of the planetary gear 22 that rotates the planetary gear 22. The planetary carrier 29 has a first carrier having a ball catch 33.
, which drives a shaft 64 rotatably extending axially within the transmission gearing 4 via the coupling ring 32 . The end of shaft 64 remote from drive shaft 19 engages output shaft 38 . A third planetary gear 76 downstream of the output shaft 38 is arranged in the front part 6 of the power wrench casing 5. When the load moment of the output shaft 38 exceeds a predetermined value, the coupling member 36 of the first coupling 32
moves, the first turnip ring 32 is disengaged, and the pawls 49 and 49' of the second coupling 48 engage with each other. As a result, the sun gear 25 of the second planetary gear 26 is rotated. At this time, the sun gear 25 is
The outer teeth of the planetary gear 17 of the planetary gear 26 mesh with the outer teeth of the planetary gear 17. While the first force knob ring 32 is disengaged and the second force knob ring 48 is engaged;
The sun gear 75 of the third planetary gear 76 is the second planetary gear 2
6 planetary carriers 52. The planet carrier 52 has a shoulder 73 with internal teeth cut into it that mesh with the shaft 64 . The inner teeth of the shoulder 73 mesh with the outer teeth of the shaft 64, so that the shaft 64 can rotate freely.

When the first coupling 32 is in the engaged state, the output shaft 3
8 rotates at relatively high speed and low torque. The coupling member 36 moves to release the first coupling 32 from the coupling state, and the second coupling 48
When engaged, the second planetary gear 26 becomes secondary with respect to the first planetary gear 21 and the output shaft 3
8 is rotated at low speed and with high torque.

9 and 10 show movable coupling member 36
movement of the second coupling 4 is prevented, and the second coupling 4
8 is always in an engaged state, but the first coupling 32
FIG. 7 illustrates a locking device 77 that is always disengaged and configured to allow the power wrench to operate at a relatively high torque but low speed in load mode. An adjustment ring 78 is provided on the outside of the coupling casing 5. The adjusting ring 78 is provided with a pin 79 which engages with the casing 5. The pin 79 is guided in a curved switching groove 80 (see FIG. 10) formed in the wall of the casing 5. The end of the pin 79, which projects into the casing 5, carries a slider 81 with a ball path 82. A ball 83 housed in ball path 82 engages a recess 84 in movable coupling member 36 . When the adjustment ring 78 is rotated, the spring 46
The slider 81 moves toward the coupling member 55 of the second coupling 48 against the action of the slider 81, and the pawls 49 and 49' of the second turnip ring 48 engage with each other to perform interlocking.

In the above-described state in which the second coupling 48 is in the engaged state and the first coupling 32 is released from the engaged state, the slider 81 is prevented from sliding by the locking device 77. However, while the slider 81 is held moved towards the output shaft of the transmission gearing 4, the ball 82 can roll on the slider 81, so the coupling member 36 can move freely. .

11 and 12 are cross-sectional views of a first coupling 32 of a torque responsive transmission gearing constructed in accordance with another embodiment of the present invention. This coupling 32 differs from the coupling described above with reference to FIGS. 5 and 6 in that the coupling body 31 carrying the spring 60 is arranged axially with respect to the drive shaft. Only. According to this configuration, the structure of the transmission gear device that operates according to torque can be simplified.

The coupling body 31, the spring 60, and the ball 34, which are arranged in the axial direction of the first coupling 32, cooperate to be movable in the axial direction common to the first and second couplings 32 and 48. A coupling member 36 is formed. As shown in FIG. 11, the common coupling member 36 has been displaced to the high speed mode position. In this state, the pawls 49 and 49' of the second coupling 48 are released from the engaged state, but the first coupling 32 is maintained in the engaged state. In this high speed mode,
The ball 34 of the first coupling 32, which is pressed by the spring 60, is pushed into the hemispherical recess 8 of the annular member 86.
5 and the annular member 86 engages the output shaft of the power wrench. When the load moment exceeds a predetermined limit value, the common coupling 36 moves axially, the pawls 49 and 49' of the second coupling 48 engage each other, and the balls 34 of the first coupling 32 slides out of the recess 85 in the annular member 86. This results in
The first coupling 32 will be disengaged.

The first also occurs when the ball 34 is accommodated in the recess 85 of the annular member 86 and is pressed into the pocket hole 50 of the coupling body 31 against the action n1 of the spring 60.
Since the coupling 32 slides, there is a high degree of safety to prevent damage from occurring.

[Brief explanation of drawings]

Fig. 1 is an inverted view illustrating the entire power wrench according to the present invention, Fig. 2 is a conceptual diagram illustrating the functions of a transmission gear device that operates according to torque, and Fig. 3 is a diagram illustrating the functions of a transmission gear device that operates according to torque. FIG. 4 is a cross-sectional view similar to FIG. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3, including a partial plan view of the transmission gear shown in FIG. FIG. 6 is a cross-sectional view taken along the line Vl--Vl in FIG. Illustrated conceptual diagram, FIG. 8, shows the torque-dependent transmission gearing illustrated in FIG. 7, with the second coupling disposed on the input side of the second gear stage. FIG. 9 is a partial cross-sectional view illustrating a locking device that prevents movement of a movable coupling member; FIG. 10 is a transmission gear device that operates in response to torque; FIG. 11 shows a first coupling of a torque responsive transmission gear constructed in accordance with another embodiment of the present invention; FIG. 12 is a partial cross-sectional view of X1l- in FIG.
A cross-sectional view taken along the line XII. DESCRIPTION OF SYMBOLS 1... Drive part, 2... Operating lever, 3... Handle member, 4... Speed change gear device, 5... Casing, 6
...Casing front part, 7... Head, 8... Compartment, 11.12... Drive branch, 17... Internal tooth, 18...
... Ball bearing, 19 ... Drive shaft, 2
0.25...Sun gear, 21...First planet gear,
21'... First gear stage, 22... Planetary gear, 23
．． 23'...Bearing, 24...Output shaft,
26...Second i! Star gear, 26'... Second gear stage, 27... Planet gear, 29... Planet carrier, 30
... Shaft-shaped projection, 31... Coupling body, 32, 48... Coupling, 33... Ball.
Catch, 34...Ball, 35...Engagement path, 3
6... Coupling member, 37... Cylindrical projection,
38... Output shaft, 39... Guide curved surface, 40...
...triangular opening, 40a, 40b...slanted side, 4
1... Guide element, 46... Spring, 47...
Idle path, 48...second coupling, 49.
49'...Claw, 50...Pocket hole, 51.51'
... Ball bearing, 52 ... Planetary carrier,
53.54 Ball bearing, 55 Coupling body, 56 Axial hole, 60 Spring, 61 Dent, 64 Shaft, 73
... Shoulder, 75 ... Sun gear, 76 ... Third planet gear, 77 ... Locking device, 78 ... Adjustment ring, 79 ... Pin, 80 ... Guide groove, 81 ...Slider, 82...Ball path, 83...Ball,
84.85...dent, 86...annular member.

Claims (1)

[Scope of Claims] (1) A first gear stage (21') having a first planetary gear (21) and a constant transmission ratio;
a second gear stage (26') arranged in line with the second gear stage (26');
a common coupling member (36) which is normally displaced in one of the two positions and is adapted to occupy the other position when the load torque exceeds a predetermined limit value. The first and second couplings (32
.
6′) are continuously driven in two parallel drive branches (
11, 12), and the output of the first gear stage (21') is connected to the first coupling (32).
is transmitted to the output shaft (38) via a first drive branch (11) with a second coupling (48) and a second gear stage (26'). the couplings (32, 48) being transmitted via the drive branch (12) to the output shaft (38) and in each of the two positions of the common coupling member (36);
A power wrench characterized in that only one of the two is in an engaged state. 2. The power transmission according to claim 1, characterized in that: (2) the second coupling (48) in the second drive branch is arranged on the output side of the second gear stage (26');
wrench. (3) the second coupling (4) in the second drive branch;
2. Power wrench according to claim 1, characterized in that 8) is arranged on the input side of the second gear stage (26'). (4) The output shaft (
38), and when the load torque exceeds a predetermined limit value, the coupling member (36) moves in the axial direction while contacting the guide curved surface (39), and the second coupling member (48) 2. The power wrench according to claim 1, wherein the power wrench is in an engaged state. (5) the guide curved surface (39) limits the triangular opening (40), and the guiding element (41) comes into contact with one corner of the triangular opening (40) by being displaced in the axial direction; Power wrench according to claim 4, characterized in that the triangular opening (40) exhibits a symmetrical shape with respect to the axis of the output shaft (38). (6) A guiding curved surface (39) is provided on the output shaft (38), and the guiding element (41) is connected to the coupling member (3).
6) The power wrench according to claim 4, wherein the power wrench is provided in the power wrench. (7) the first coupling (32) comprises at least one ball catch (33), the ball catch (33) being disposed on the coupling member (36); ) in which the ball (34) of the coupling is engaged with the engagement path (35) having the recess (61) and the ball catch (33) is connected to the planetary carrier (29) of the planetary gear (21). Main body (31
2. The power wrench according to claim 1, wherein the power wrench is provided at a. (8) the first coupling (32) has an idling path (47) adjacent to the engagement path (35) of the coupling body (31);
7. The idling path (35) receives the ball (34) when the ball (34) is engaged.
Power wrench as described. (9) Planetary carrier (29) of first planetary gear (21)
has an output shaft (24) extending coaxially with respect to the drive shaft (19);
) extends beyond the second gear stage (26').
8. Power wrench according to claim 7, characterized in that the coupling body (31) is arranged on the protrusion. (10) The second gear stage (26') is connected to the second planetary gear (26')
6), and the planetary gears (22, 27) of the first and second planetary gears (21, 26) mesh with the internal teeth (17) of the common hollow wheel. The power wrench according to claim 1, characterized in that: (11) Claim 1 characterized in that the hollow wheel is constituted by a casing (5) of a power wrench.
Power wrench listed in 0. (12) The casing (5) of the power wrench is rotatably supported and the profile is such that the casing (5) is fitted with a support for supporting the casing (5) on a stationary abutment. 12. Power wrench according to claim 11, characterized in that it comprises a partition (8) with a closed section (8). (13) The output shaft (38) is connected to the third planetary gear (76)
) carries a sun gear (20) of the sun gear (20).
2. Power wrench according to claim 1, characterized in that the power wrench (4) is arranged downstream of the transmission gear (4). 14. Power according to claim 1, characterized in that the transmission gearing (4) is provided with a locking device (77) for locking the movable coupling member (36) in one of two positions. ·wrench.