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Patent Searching and Data


Title:
IMPULSE WRENCH WITH AN AUXILIARY POWER CONTROL MEANS.
Document Type and Number:
WIPO Patent Application WO/2017/207548
Kind Code:
A1
Abstract:
An impulse wrench comprising a housing (10), a motor, and an output shaft (12) extending from the forward end of the housing (10), wherein the housing (10) includes a pistol grip handle (11) with a trigger (15) for operating a primary power control device (20), wherein an auxiliary power control device (17) is provided at the rear end of the housing (10) for an alternative control of the power supply to the motor, and a connection device (13) for a power supply conduit (24) is provided at the outer end of the pistol grip handle (11) by which the wrench is connected to an over-head suspension device in an "upside-down" rest position. The auxiliary power control device (17) is intended to facilitate use of the power wrench in the "upside- down" orientation.

Inventors:
PYDDOKE, Thomas David (Törners väg 62, Lidingö, 181 57, SE)
WIKLUND, Niclas Mikael (Tibastvägen 4, Älta, 138 35, SE)
Application Number:
EP2017/063003
Publication Date:
December 07, 2017
Filing Date:
May 30, 2017
Export Citation:
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Assignee:
ATLAS COPCO INDUSTRIAL TECHNIQUE AB (105 23 STOCKHOLM, 105 23, SE)
International Classes:
B25B21/00
Attorney, Agent or Firm:
THOLIN, Thomas (ATLAS COPCO INDUSTRIAL TECHNIQUE AB, Patent Department, Stockholm, 105 23, SE)
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Claims:
Claims .

1. An impulse wrench comprising a housing (10), a motor, and an output shaft (12) extending from a forward end of the housing (10) , wherein the housing (10) includes a pistol grip handle (11) with a trigger (15) for operating a primary power control device (20),

c h a r a c t e r i z e d in that an auxiliary power control device (17) is provided on the housing (10) for an alternative control of the power supply to the motor.

2. Impulse wrench according to claim 1, wherein a connection device (13) is provided at the outer end of the pistol grip handle (11) and intended to be connected to an overhead suspension device thereby suspending the impulse wrench in an "upside-down" rest position.

3. Impulse wrench according to claim 1 or 2, wherein said auxiliary power control device (17) is located at a rear end of the housing (10) and comprises a push button (18) which is arranged to be activated by a force applied in the direction of the output shaft (12) .

4. Impulse wrench according to anyone of claims 1-3, wherein an operating mode switching device (23) is provided to be shifted between a "forward" position and a "reverse"

position, and said auxiliary power control device (17) is arranged to be operable in said "forward" position only of said switching device (23) .

5. Impulse wrench according to claim 4, wherein a position retaining mechanism (28) is provided for retaining the primary power control device (20) in open position as the mode switching device (23) occupies its "forward" position.

6. Impulse wrench according to anyone of claims 2-5, wherein said suspension device comprises a power supply conduit (24) .

Description:
Impulse wrench with an auxiliary power control means.

The invention relates to an impulse type power wrench including a housing, a motor, and an output shaft, wherein the housing includes a pistol grip handle with a trigger for controlling the power supply to the motor.

Power wrenches of this type are commonly supplied with power via a power supply line, usually a pressure air hose, connected to the lower or outer end of the pistol grip handle, and in many cases the wrench is suspended in the pressure air hose which extends from above and connected to a weight balancing device. This means that the power wrench when in a rest position is suspended in an "upside-down" orientation with the pistol grip directed upwards. To be put into operation the wrench has to be pulled down against the suspension force of the weight balancing device .

However, instead of turning the wrench around when pulled down to enable a proper grasp on the pistol grip handle operators tend to grasp the wrench housing from behind in its suspended "upside-down" orientation and reach for the trigger on the pistol grip handle by a finger to start the wrench. In many wrench operation situations this means a quicker positioning of the wrench and a shortened overall tool operation time. However, it requires a rather awkward and uncomfortable finger

manipulating of the trigger to put the wrench into operation, and the ergonomic efforts originally paid at designing the wrench has no relevance in this situation.

Since impulse wrenches do not cause any noticeable torque reaction during operation the operator does not have to support the wrench by the pistol grip to counteract any reaction force. A steady grasp on the housing, comfortable or not, will do.

It is an object of the invention is to provide a pistol type impulse wrench by which a more comfortable handling of the wrench in an "upside-down" orientation is offered. The "upside- down" orientation means the handle of the tool, in use, is orientated above the tool motor instead of underneath.

It is a further object of the invention to provide a pistol type impulse wrench by which the operation control means of the wrench is adapted to facilitate use of the wrench in an "upside- down" orientation.

It is a still further object of the invention to provide a pistol type impulse wrench having an auxiliary power control device arranged on the wrench housing to facilitate operation of the wrench in an "upside-down" orientation.

Other objects and advantages of the invention will appear from the following specification and claims.

A preferred embodiment of the invention is described below with references to the accompanying drawings.

In the drawings

Fig. 1 shows a side view of an impulse type power wrench according to the invention.

Fig. 2a shows schematically the power supply system of the impulse wrench in Fig. 1 and illustrates a power wrench rest position .

Fig. 2b shows the power supply system in Fig. 2a and illustrates a "forward" operating mode.

Fig. 2c shows the system in Fig. 2a and illustrates a "reverse" operating mode.

Fig. 1 shows a pneumatic impulse wrench having a housing 10 with a pistol grip handle 11, and includes a pneumatic motor

drivingly connected to a square ended output shaft 12 via a non- illustrated impulse unit. The pistol grip handle 11 comprises both a pressure air inlet passage having a socket 13 for receiving a pressure air supply conduit 24, and an exhaust passage having a noise damping outlet piece 14. Moreover, the pistol grip carries a finger operated trigger 15 for operating a primary pressure inlet valve, and a directional valve for shifting the motor operation between "forward" operation mode and "reverse" operation mode. The directional valve is operated by a switching device (23) , here exemplified by a arranging a rotatable knob 16 located close to the trigger 15.

In common applications the pressure air supply conduit 24 has the form of a hose is hanging down from an overhead position where it is coupled to a weight balancing device, wherein the pressure air hose is connected to the socket 13 at the outer end of the pistol grip handle 11. Since the pressure air hose is extended from an over-head position the wrench will be suspended in an uplifted upside-down position with the pistol grip handle 11 directed upwards. When putting the wrench into operation the operator would have to pull down the wrench from its suspended position, but instead of turning it around to get the pistol grip into a "normal" operating position the operator usually grasps the rear end of the wrench housing 10 and start operating the wrench in its upside-down position and starting the wrench by pressing the trigger 15 by one of his fingers. However, this self-chosen wrench position is rather awkward and tiresome for the operator as it requires an extra effort to reach the trigger 15 with a finger from behind the wrench housing. Yet, operators still prefer this way of using the wrench, because it is a quick way to put the wrench into work and to thereby bring down the overall time for an operation cycle. Since there is no

noticeable torque reaction to counteract at this type of wrenches this un-orthodox wrench handling approach is not only acceptable but preferable by operators, and in order to adapt the wrench to this way of manual support and handling there is provided an auxiliary power control valve 17 operative by a push button 18 located at the rear end of the housing 10. The function of the auxiliary power control valve 17 will be described in further detail below.

In Figs. 2a-c there is schematically illustrated a control system by which the power wrench may be operated in two

different modes, namely a "forward" mode, and a "reverse" mode, wherein the "forward" mode means rotation of the wrench motor 19 in a screw joint tightening direction and the "reverse" mode means rotation of the wrench motor 19 in a screw joint loosening direction. The system comprises a primary pressure air inlet valve 20 connected to a pressure air source 21 via the pressure air conduit 24 and manually operated by the trigger 15 between a closed position and an open position. The primary air inlet valve 20 is biased toward its closed position by a spring 22. The system further includes a mode switching device in the form of a directional valve 23 which is shiftable between a "forward" position and a "reverse" position, and an auxiliary power control valve 17 as mentioned above. The latter has an on/off function and is manually shiftable by the push button 18 from a closed position to an open position. A spring 25 is arranged to bias the valve 17 towards its closed position. The system is connected to the power wrench motor 19 by two passages 26, 27.

The control system also comprises a schematically illustrated a movement transferring and position retaining mechanism 28 provided between the primary air inlet valve 20 and the

directional valve 23. This mechanism 28 is arranged to transfer movement from the directional valve 23 to the primary inlet valve 20 and to retain the latter in its open position in the "forward" operation mode of the wrench. This arrangement is intended to enable the operator to use the auxiliary power control valve 17 in the "forward" operating mode of the wrench without having to shift the primary inlet valve 20 too.

As illustrated in the drawing figures the retaining mechanism 28 comprises an elongate member 30 connected to the directional valve 23 and extending in the movement direction of the latter. This member 30 is provided with a heel 31 and two spaced indentations 33, 34, wherein the heel 31 is arranged to

cooperate with a hook 32 carried on the inlet valve 20. Shifting the directional valve 23 to the left, i.e. into its "forward" position, the heel 31 engages the hook 32 and brings the inlet valve 20 its open position. The two indentations 33, 34 are intended to be alternatively engaged by a spring biased plunge 35 to thereby accomplish directional valve 23 retaining and position defining action. By this device the directional valve will be retained in either one of its two operative positions. The retaining device also functions as a holding means for retaining both the directional valve 23 in its "forward" position and the inlet valve 20 in its open position. Retaining the primary inlet valve 20 in its open position is accomplished by the engagement between the heel 31 and the hook 32. See Fig. 2b. In the "reverse" operation mode of the power wrench the directional valve 23 is put into its right hand position, whereby the heel 31 is moved out of engagement with hook 32 and the inlet valve 20 is free to return to its closed position.

The auxiliary valve 17 is operative to control the wrench operation in the "forward" operation mode when the primary inlet valve 20 is retained in its open position, but is bypassed without any influence on the power control in the "reverse" operation mode. See Fig. 2c.

So, in order to obtain the full benefit from this auxiliary valve 17 arrangement the trigger operated inlet valve 20 is retained in its open position by means of the retaining

mechanism 28 in the "forward" operation mode, which means that the operator does not have to manipulate the trigger 15 to activate the power wrench. In the "reverse" operation mode, which is far less frequently used than the "forward" direction, the inlet valve 20 remains unlocked and could be operated by the trigger 15 as originally intended to start and control the operation of the power wrench.

It is to be understood that the embodiments of the invention are not limited to the above described example but could be freely varied within the scope of the claims. For instance, the pressure air inlet valve 20 and the auxiliary valve 17 may very well be biased toward their closed positions by air pressure instead of springs as described above. Also the retaining mechanism 28 may be of a quite different design than the one illustrated and described above but should provide the very same function .

Although the invention is described in connection with a pneumatic impulse wrench the invention may as well be applied on electric impulse wrenches. Also in that case the power wrench may be suspended in an upside-down orientation in an overhead weight balancing device and grasped by the operator in that position for performing an intended work. The power control and directional valves described above would of course be replaced by electric switches as would the retaining mechanism.