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Title:
A POWER TOOL WITH WIRELESS COMMUNICATION CAPABILITY
Document Type and Number:
WIPO Patent Application WO/2021/244893
Kind Code:
A1
Abstract:
A power tool comprising: a first structure (5), a second structure (3), a first coil structure (9) arranged on the first structure (5), a second coil structure (11) arranged on the second structure (3), wherein the second coil structure (11) is configured to inductively interact with the first coil structure (9) to enable wireless communication of data between the first coil structure (9) and the second coil structure (11), a first screen (15) arranged between the first coil structure (9) and the first structure (5), the first screen (15) being configured to redirect magnetic flux induced by the first coil structure (9) from the first structure (5), and a second screen (17) arranged between the second coil structure (11) and the second structure (3), the second screen (17) being configured to redirect magnetic flux induced by the second coil structure (11) from the second structure (3).

Inventors:
CARLSSON SIMON (SE)
HALLBERG DANIEL (SE)
MATTIAS ERICSSON MATTIAS (SE)
Application Number:
PCT/EP2021/063801
Publication Date:
December 09, 2021
Filing Date:
May 25, 2021
Export Citation:
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Assignee:
ATLAS COPCO IND TECHNIQUE AB (SE)
International Classes:
H02J50/10; H02J50/70; H02J50/80
Domestic Patent References:
WO2019201589A12019-10-24
Foreign References:
US20140306654A12014-10-16
EP3611820A12020-02-19
US20170035402A12017-02-09
Download PDF:
Claims:
CLAIMS

1. A power tool (1) comprising: a first structure (5), a second structure (3), a first coil structure (9) arranged on the first structure (5), a second coil structure (11) arranged on the second structure (3), wherein the second coil structure (11) is configured to inductively interact with the first coil structure (9) to enable wireless communication of data between the first coil structure (9) and the second coil structure (11), a first screen (15) arranged between the first coil structure (9) and the first structure (5), the first screen (15) being configured to redirect magnetic flux induced by the first coil structure (9) from the first structure (5), and a second screen (17) arranged between the second coil structure (11) and the second structure (3), the second screen (17) being configured to redirect magnetic flux induced by the second coil structure (11) from the second structure (3).

2. The power tool (1) as claimed in claim 1, wherein the first screen (15) is a first ferrite sheet, and the second screen (17) is a second ferrite sheet.

3. The power tool (1) as claimed in claim 1 or 2, wherein the first coil structure (9) is arranged concentrically with the second coil structure (11).

4. The power tool (1) as claimed in any of the preceding claims, wherein the first coil structure (9) is a rectangular coil that is folded to follow a first surface of the first structure (5) in a circumferential direction of the power tool (1), and the second coil structure (11) is a rectangular coil that is folded to follow a second surface of the second structure (3) in the circumferential direction.

5. The power tool (1) as claimed in any of claims 1-3, comprising a first flexible substrate (21) wherein the first coil structure (11) is printed on the first flexible substrate (21), forming a first flexible printed circuit board, PCB, (19) and wherein the first flexible PCB (19) is folded to follow a first surface of the first structure (5) in a circumferential direction of the power tool (1). 6. The power tool (1) as claimed in claim 5, comprising a second flexible substrate (25) wherein the second coil structure (11) is printed on the second flexible substrate (25), forming a second flexible printed circuit board, PCB, (23) and wherein the second flexible PCB (23) is folded to follow a second surface of the second structure (3) in the circumferential direction.

7. The power tool (1) as claimed in claim 6, wherein the first coil structure (9) comprises a first power transfer coil (9a) and a separate first data transfer coil (9b) and the second coil structure (11) comprises a second power transfer coil (11a) configured to inductively interact with the first power transfer coil (9a), and a separate second data transfer coil (lib) configured to inductively interact with the first data transfer coil (9b).

8. The power tool (1) as claimed in any of the preceding claims, comprising a modulator circuit (35) configured to modulate data to obtain a modulated signal, wherein the modulator circuit (35) is configured to energise the second coil structure (11) with the modulated signal to induce the modulated signal in the first coil structure (9).

9. The power tool (1) as claimed in claim 8, comprising a demodulator circuit (33) configured to demodulate the modulated signal induced in the first coil structure (9) to obtain the data.

10. The power tool (1) as claimed in claim 8 or 9, comprising a power transfer circuit (31) configured to energise the first coil structure (9) with a power signal to induce the power signal in the second coil structure (11) to power the modulator circuit (35).

11. The power tool (1) as claimed in claim 10, wherein the power transfer circuit (31) comprises a switching circuit configured to switch the voltage across the first coil structure (9) to generate the power signal.

12. The power tool (1) as claimed in any of the preceding claims, comprising a main body (5) and an interchangeable gear attachment (3) configured to be removably attached to the main body (5), wherein the second structure (3) is the interchangeable gear attachment.

13. The power tool (1) as claimed in any of claims 1-11, comprising a rotatable member, wherein the second structure (3) is the rotatable member.

14. The power tool (1) as claimed in any of the preceding claims, comprising a main body (5), wherein the first structure (5) is the main body (5).

Description:
A POWER TOOL WITH WIRELESS COMMUNICATION CAPABILITY

TECHNICAL FIELD

The present disclosure generally relates to power tools.

BACKGROUND

Industrial power tools such as nutrunners are widely used in the manufacturing industry, e.g. in vehicle manufacturing and the aerospace industry. Power tools of this type typically have a tool head which interacts with the work piece and a main body which is held by the user when operating the power tool. The main body may alternatively form part of a robot.

Manufacturing processes usually require high precision control of the torque applied by the power tool. The power tools therefore typically comprise a torque transducer configured to measure the applied torque. The torque transducer may be provided in the tool head or the main body, or in both.

The torque transducer may for example comprise a strain gauge arranged on a rotating part in the power tool. Slip rings may be used for conveying the measurement signal by the strain gauge to stationary components. WO2019201589 A1 discloses a power tool of this type. One potential drawback with this configuration is that the measurement signal may be subjected to noise as the slip ring degrades over time.

SUMMARY

In some applications it may be desirable to have interchangeable tool parts, which may be used for different applications in a manufacturing process. The tool head, such as an angle head may therefore be removably connected to the main body.

It may be desirable to be able to send data between the tool head and the main body. For example, the torque transducer may be provided in the tool head and the measurement signals may have to be passed from the tool head to the main body and further to a user interface or a power tool controller.

In view of the above, an object of the present disclosure is to provide a power tool which solves, or at least mitigates, the problems of the prior art.

There is hence provided a power tool comprising: a first structure, a second structure, a first coil structure arranged on the first structure, a second coil structure arranged on the second structure, wherein the second coil structure is configured to inductively interact with the first coil structure to enable wireless communication of data between the first coil structure and the second coil structure, a first screen arranged between the first coil structure and the first structure, the first screen being configured to redirect magnetic flux induced by the first coil structure from the first structure, and a second screen arranged between the second coil structure and the second structure, the second screen being configured to redirect magnetic flux induced by the second coil structure from the second structure.

Data transfer is thus provided wirelessly between the first coil structure and the second coil structure. The risk of signal degradation over time may thus be reduced. Furthermore, as the first structure and/or the second structure may typically include ferrous material, the first screen and the second screen reduce magnetic losses due to eddy currents induced in the first structure and the second structure.

The power tool may for example be a nutrunner.

The first coil structure may be mechanically flexible.

The second coil structure may be mechanically flexible.

According to one example, the first coil structure and the second coil structure may be configured to be operated based on a radio-frequency identification (RFID) standard .

According to one embodiment the first screen is a first ferrite sheet, and the second screen is a second ferrite sheet.

According to one embodiment the first coil structure is arranged concentrically with the second coil structure.

According to one embodiment the first coil structure is a rectangular coil that is folded to follow a first surface of the first structure in a circumferential direction of the power tool, and the second coil structure is a rectangular coil that is folded to follow a second surface of the second structure in the circumferential direction. The rectangular, or essentially rectangular as the corners of the rectangular may be somewhat rounded, improves the signal transmission. Moreover, it can conveniently be placed in existing grooves of power tools. One embodiment comprises a first flexible substrate wherein the first coil structure is printed on the first flexible substrate, forming a first flexible printed circuit board, PCB, and wherein the first flexible PCB is folded to follow a first surface of the first structure in a circumferential direction of the power tool.

One embodiment comprises a second flexible substrate wherein the second coil structure is printed on the second flexible substrate, forming a second flexible printed circuit board, PCB, and wherein the second flexible PCB is folded to follow a second surface of the second structure in the circumferential direction.

According to one embodiment the first coil structure comprises a first power transfer coil and a separate first data transfer coil and the second coil structure comprises a second power transfer coil configured to inductively interact with the first power transfer coil, and a separate second data transfer coil configured to inductively interact with the first data transfer coil. The first coil structure and the second coil structure may hence form a dual coil transformer. This configuration further improves signal transmission. The first power transfer coil and the second power transfer coil may be optimised for transmitting a power signal. The first data transfer coil and the second data transfer coil may be optimised for transmitting a modulated signal comprising data. The modulated signal will thereby be attenuated less detrimentally than if the first coil structure and the second coil structure form a single coil transformer. Alternatively, the first coil structure may comprise a single coil and the second coil structure may comprise a single coil. The first coil structure and the second coil structure may form a single coil transformer. One embodiment comprises a modulator circuit configured to modulate data to obtain a modulated signal, wherein the modulator circuit is configured to energise the second coil structure with the modulated signal to induce the modulated signal in the first coil structure. The modulator circuit may for example be configured to perform modulation using amplitude-shift keying (ASK) modulation. The ASK modulation may for example be on-off keying (00K) modulation.

One embodiment comprises a demodulator circuit configured to demodulate the modulated signal induced in the first coil structure to obtain the data.

The power tool may comprise a controller, or the power tool may form part of a power tool system comprising an external controller. The demodulator circuit may be configured to directly or indirectly provide the data to the controller.

One embodiment comprises a power transfer circuit configured to energise the first coil structure with a power signal to induce the power signal in the second coil structure to power the modulator circuit.

The power transfer circuit may be configured to energise the first coil structure with the power signal having a frequency that is lower than a frequency of the modulated signal. The power signal may for example have a frequency that is of the order 10 or more lower than the frequency of the modulated signal.

By using different frequencies for the power signal and the modulated signal power transfer and signal transfer may be performed simultaneously. This may especially be the case when the first coil structure and the second coil structure comprise single coils and form a single coil transformer.

The power tool may comprise a high pass filter. The high pass filter may be configured to separate the modulated signal from the power signal after it has been induced in the first coil structure. The modulated signal can thereby be recovered before it is demodulated by the demodulator .

The power signal may be of several orders greater amplitude than the modulated signal. The high pass filter may preferably have a very steep roll-off rate. The high pass filter may be a multi-pole filter of high order to efficiently separate the modulated signal from the power signal. The high pass filter may for example have at least 4 poles such as at least 6 poles or at least 8 poles.

The power transfer circuit may be configured to energise the first power transfer coil.

The modulator circuit may be configured to energise the second data transfer coil.

According to one embodiment the power transfer circuit comprises a switching circuit configured to switch the voltage across the first coil structure to generate the power signal.

The switching circuit may for example comprise a flyback converter, an H-bridge, or a class-E amplifier.

One embodiment comprises a main body and an interchangeable gear attachment configured to be removably attached to the main body, wherein the second structure is the interchangeable gear attachment.

The second structure may have a second structure surface that faces a main body surface of the main body, wherein the second coil structure is arranged on the second structure surface.

The interchangeable gear attachment may be a tool head, such as an angle head or a straight head.

One embodiment comprises a rotatable member, wherein the second structure is the rotatable member.

The rotatable member may for example be a planetary gear, an output shaft, a crown wheel or a coupling structure coupling the output shaft to the crown wheel, of the power tool.

The rotatable member may be provided with a transducer or other electronics unit electrically connected to the second coil structure. The transducer may for example be a torque transducer, an angle sensor or a force measurement sensor.

The torque or other measurements may thereby be transferred wirelessly from the rotatable member. One embodiment comprises a main body, wherein the first structure is the main body.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, etc.", unless explicitly stated otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

The specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 shows an example of a power tool;

Fig. 2 shows a detail of a main body and tool head of the power tool in Fig. 1;

Fig. 3 shows a detail of a longitudinal section at the interface between the main body and the tool head of the power tool in Fig. 1;

Fig. 4 shows an example of a coil structure;

Fig. 5 shows another example of a coil structure;

Fig. 6 schematically shows an example of an inductive coupling for power transfer and data transfer in a power tool; and

Fig. 7 schematically shows another example of an inductive coupling for power transfer and data transfer. DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description.

Fig. 1 shows an example of a power tool 1. The power tool 1 may for example be a nutrunner. The power tool 1 has a tool head 3 and a main body 5. The tool head 3 is attached to the main body 5. In the present example, the tool head 3 is removably attached to the main body 5. The tool head 3 may be an interchangeable tool head or interchangeable gear attachment. The tool head 3 may for example be an angle head or a straight head.

The main body 5 may comprise a handle 7. When the power tool 1 is operated, a user may grip the handle 7 to hold the power tool 1. Fig. 2 shows a close-up view of the power tool 1.

According to the example, the tool head 3 has an end portion 3a that can be connected to the main body 5. The main body 5 has an opening 5a configured to receive the end portion 3a. The main body 5 is herein also referred to as a "first structure". The tool head 3 is herein also referred to as a "second structure".

The main body 5 is provided with a first coil structure 9. The first coil structure 9 is in the present example arranged on a first surface of the main body 5. The first surface may for example be an inner surface of a channel formed by the opening 5a.

The first coil structure 9 may extend along the circumferential direction of the power tool 1.

The end portion 3a of the tool head 3 is provided with a second coil structure 11. The second coil structure 11 is provided on a second surface of the tool head 3, which when assembled with the main body 5 is arranged inside the main body 5. The second surface may for example be an outer surface of the end portion 3a.

The second coil structure 11 may extend along the circumferential direction of the power tool 1.

When the tool head 3 is assembled with the main body 5 the first coil structure 9 and the second coil structure 11 are arranged concentrically.

Fig. 3 shows a detail of a longitudinal section of the power tool 1 when the tool head 3 has been assembled with the main body 5. Fig. 3 shows the interface between the main body 5 and the tool head 3. The end portion 3a of the tool head 3 extends into the main body 5. In the example, an airgap 13 is provided between the main body 5 and the end portion 3a. The first coil structure 9 and the second coil structure 11 are configured to electromagnetically interact with each other over the airgap 13.

The power tool 1 includes a first screen 15 arranged between the first coil structure 9 and the main body 5. The first screen 15 is configured to redirect magnetic flux induced by the first coil structure 9 from the main body 5.

The first screen 15 may be a first ferrite sheet. The first screen 15 may be mechanically flexible to allow it to bear against the main body 5 as it extends along the circumferential direction of the power tool 1.

The power tool 1 includes a second screen 17 arranged between the second coil structure 11 and the second surface of the tool head 3. The second screen 17 is configured to redirect magnetic flux induced by the second coil structure 11 from the tool head 3.

The second screen 17 may be a second ferrite sheet. The second screen 17 may be mechanically flexible to allow it to bear against the tool head 3 as it extends along the circumferential direction of the power tool 1.

Fig. 4 shows an example of an implementation of the first coil structure 9 and the second coil structure 11. According to this example, the power tool 1 comprises a first flexible substrate 21 on which the first coil structure 9 is printed. The first flexible substrate 21 and the first coil structure 9 form a first flexible printed circuit board (PCB) 19. The first flexible PCB 19 is folded to follow the first surface of the main body 5. The power tool 1 comprises a second flexible substrate 25 on which the second coil structure 11 is printed. The second flexible substrate 25 and the second coil structure 11 form a second flexible printed circuit board (PCB) 23. The second flexible PCB 23 is folded to follow the second surface of the tool head 3.

In the example shown in Fig. 4, the first coil structure 9 is a single coil and the second coil structure 11 is a single coil. Fig. 5 shows another example of the first coil structure 9 and the second coil structure 11. In this example the first coil structure 9 is a rectangular coil seen to the left in Fig. 5 which is folded to follow the main body 5 in the circumferential direction of the power tool 1. The rectangular coil may have a short side 27 and a long side 29. The rectangular coil is folded along its long side 29.

The second coil structure 1 is a rectangular coil folded to follow the tool head 3 in the circumferential direction of the power tool 1. The rectangular coil may have a short side 27 and a long side 29. The rectangular coil is folded along its long side 29.

Turning now to Fig. 6 the power tool 1 comprises a power transfer circuit 31 and a demodulator circuit 33. The power transfer circuit 31 and the demodulator circuit are electrically connected to the first coil structure 9. The first coil structure 9 is in this example a single coil.

The first structure, i.e. the main body 5 comprises the power transfer circuit 31 and the demodulator circuit 33. The power tool 1 comprises a modulator circuit 35. The modulator circuit 35 is electrically connected to the second coil structure 11.

The power tool 1 may also comprise a circuit 37. The circuit 37 may for example be a transducer such as a torque transducer, an angle sensor or a force measurement sensor. The circuit 37 may alternatively or additionally comprising processing circuitry, for example to process measurements by the torque transducer, angle sensor, or force measurement sensor.

The circuit 37 is electrically connected to the second coil structure 11. The circuit 37 is electrically connected to the modulator circuit 35.

The second structure, or tool head, comprises the modulator circuit 35. The second structure, or tool head, comprises the circuit 37.

The power transfer circuit 31 is configured to energise the first coil structure 9 with a power signal to provide wireless power transfer to the second coil structure 11. The first coil structure 9 is configured to induce the power signal in the second coil structure 11 which can power the modulator circuit 35 and optionally the circuit 37.

The power transfer circuit 31 may for example comprise switching circuit, such as a flyback converter, an H- bridge or a class-E amplifier. The switching circuit is configured to generate the power signal by switching a voltage, which when induced in the second coil structure 11 can drive the modulator circuit 35 and optionally the circuit 37. The modulator circuit 35 is configured to receive data/signals from the circuit 37 and to modulate the data/signals to generate a modulated signal. The data/signals may for example be measurements by the circuit 37 and/or an identifier of the type of tool head, and/or calibration data related to the tool head 3 for a controller configured to operate the power tool 1. The modulator circuit 35 is configured to energise the second coil structure 11 with the modulated signal to induce the modulated signal in the first coil structure 9.

The modulator circuit 35 may for example be configured to perform modulation using ASK modulation. The ASK modulation may for example 00K modulation.

The demodulator circuit 33 is configured to demodulate the modulated signal when it has been induced in the first coil structure 9. The data/signal may thereby be obtained on the side of the first structure, i.e. the main body 5.

According to one alternative, the main body may also be provided with a modulator circuit and the tool head may also be provided with a demodulator circuit. In this way, two-way communication may be obtained between the main body and the tool head.

The wireless power transfer and the wireless data transfer may be performed simultaneously by shifting the frequency of the modulated signal away from that of the power signal. For example, the frequency of the modulated signal may be of the order 10 or higher than the frequency of the power signal. The power tool may in this case comprise a high pass filter configured to separate the frequency of the modulated signal from the frequency of the power signal. The high pass filter may be provided in at least the main body. The high pass filter may for example form part of the demodulator circuit. Fig. 7 shows another example of a power tool 1. This example is similar to the one shown in Fig. 6. The first coil structure 9 however includes a first power transfer coil 9a and a separate first data transfer coil 9b. The first power transfer coil 9a is electrically connected to the power transfer circuit 31. The first data transfer coil 9b is electrically connected to the demodulator circuit 33.

The first power transfer coil 9a and the second power transfer coil 9b may both be printed on the first flexible substrate.

The second coil structure 11 includes a second power transfer coil 11a and a separate second data transfer coil lib.

The first coil structure 9 and the second coil structure 11 form a dual coil transformer. The dual coil transformer uses separate coil sets for power transfer and data transfer.

The second power transfer coil 11a is configured to inductively interact with the first power transfer coil 9a. The first power transfer coil 9a is configured to induce the power signal in the second power transfer coil 11a.

The second data transfer coil lib is configured to inductively interact with the first data transfer coil 9b. The second data transfer coil lib is configured to induce the modulated signal in the first data transfer coil 9b.

The second data transfer coil lib is configured to be electrically connected to the modulator circuit 35. The modulator circuit 35 is configured to energise the second data transfer coil lib with the modulated signal.

The second power transfer coil 11a is configured to be electrically connected to the modulator circuit 35 for powering the modulator circuit 35 by means of the power signal induced in the second power transfer coil 11a by the first power transfer coil 9a.

The second power transfer coil 11a and the second power transfer coil lib may both be printed on the second flexible substrate.

According to one alternative, the main body may also be provided with a modulator and the tool head may also be provided with a demodulator circuit. In this way, two-way communication may be obtained between the main body and the tool head using the dual coil transformer.

According to one variation of any example disclosed herein, both the first structure and the second structure may form part of either the main body or the tool head. For example, the first structure may be a stationary part of the main body, and the second structure may be a rotatable member. Data may thereby be transmitted wirelessly between the rotatable member and the stationary part. The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.