SE543741C2

SE543741C2 - A power tool with wireless communication capability

Info

Publication number: SE543741C2
Application number: SE2030179A
Authority: SE
Inventors: Daniel Hallberg; Mattias Ericsson; Simon Carlsson
Original assignee: Atlas Copco Ind Technique Ab
Priority date: 2020-06-02
Filing date: 2020-06-02
Publication date: 2021-07-06
Also published as: JP3241805U; DE212021000388U1; KR20230000240U; WO2021244893A1; CN219227288U; SE2030179A1

Abstract

A POWER TOOL WITH WIRELESS COMMUNICATION CAPABILITYA 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).

Description

A POWER TOOL WITH WIRELESS COMUNICATION 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, in vehicle e.g.manufacturing and the aerospace industry. Power tools ofthis type typically have a tool head which interacts withthe 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 precisioncontrol of the torque applied by the power tool. Thepower tools therefore typically comprise a torquetransducer configured to measure the applied torque. Thetorque transducer may be provided in the tool head or the main body, or in both.

The torque transducer may for example comprise a straingauge arranged on a rotating part in the power tool. Sliprings may be used for conveying the measurement signal bythe strain gauge to stationary components. WO20l920l589Al discloses a power tool of this type. One potentialdrawback with this configuration is that the measurementsignal may be subjected to noise as the slip ring degrades over time.

SUMARY 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 thetool head and the main body. For example, the torquetransducer may be provided in the tool head and themeasurement signals may have to be passed from the toolhead 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 structurearranged on the second structure, wherein the second coilstructure is configured to inductively interact with thefirst coil structure to enable wireless communication ofdata between the first coil structure and the second coilstructure, a first screen arranged between the first coilstructure and the first structure, the first screen beingconfigured to redirect magnetic flux induced by the firstcoil structure from the first structure, and a secondscreen arranged between the second coil structure and thesecond structure, the second screen being configured toredirect magnetic flux induced by the second coil structure from the second structure.

Data transfer is thus provided wirelessly between thefirst 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, thefirst screen and the second screen reduce magnetic lossesdue 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 andthe second coil structure may be configured to beoperated based on a radio-frequency identification (RFID) standard.

According to one embodiment the first screen is a firstferrite 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 arectangular coil that is folded to follow a first surfaceof the first structure in a circumferential direction ofthe power tool, and the second coil structure is arectangular coil that is folded to follow a secondsurface of the second structure in the circumferentialdirection. The rectangular, or essentially rectangular asthe corners of the rectangular may be somewhat rounded,improves the signal transmission. Moreover, it canconveniently be placed in existing grooves of power tools.

One embodiment comprises a first flexible substratewherein the first coil structure is printed on the firstflexible substrate, forming a first flexible printed circuit board, PCB, and wherein the first flexible PCB isfolded to follow a first surface of the first structure in a circumferential direction of the power tool.

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

According to one embodiment the first coil structurecomprises a first power transfer coil and a separatefirst data transfer coil and the second coil structurecomprises a second power transfer coil configured toinductively 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 structuremay hence form a dual coil transformer. Thisconfiguration further improves signal transmission. Thefirst power transfer coil and the second power transfercoil may be optimised for transmitting a power signal.The first data transfer coil and the second data transfercoil may be optimised for transmitting a modulated signalcomprising data. The modulated signal will thereby beattenuated less detrimentally than if the first coilstructure and the second coil structure form a single coil transformer.

Alternatively, the first coil structure may comprise asingle coil and the second coil structure may comprise asingle coil. The first coil structure and the second coil structure may form a single coil transformer.

One embodiment comprises a modulator circuit configuredto modulate data to obtain a modulated signal, whereinthe 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 toperform modulation using amplitude-shift keying (ASK)modulation. The ASK modulation may for example be on-off keying (OOK) modulation.

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

The power tool may comprise a controller, or the powertool may form part of a power tool system comprising anexternal controller. The demodulator circuit may beconfigured to directly or indirectly provide the data to the controller.

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

The power transfer circuit may be configured to energisethe first coil structure with the power signal having afrequency that is lower than a frequency of the modulated signal.

The power signal may for example have a frequency that isof the order lO or more lower than the frequency of the modulated signal.

By using different frequencies for the power signal andthe modulated signal power transfer and signal transfermay be performed simultaneously. This may especially bethe 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 highpass filter may be configured to separate the modulatedsignal from the power signal after it has been induced inthe first coil structure. The modulated signal canthereby be recovered before it is demodulated by the demodulator.

The power signal may be of several orders greateramplitude than the modulated signal. The high pass filtermay preferably have a very steep roll-off rate. The highpass filter may be a multi-pole filter of high order to efficiently separate the modulated signal from the powersignal. The high pass filter may for example have atleast 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 aninterchangeable gear attachment configured to besecond removably attached to the main body, wherein the 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, whereinthe 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 structurecoupling the output shaft to the crown wheel, of the power tool.

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

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 thetechnical 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, etc.", means, 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. l 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. l; Fig. 3 shows a detail of a longitudinal section at theinterface between the main body and the tool head of the power tool in Fig. l; 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 fullyhereinafter 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 thisdisclosure will be thorough and complete, and will fullyconvey the scope of the inventive concept to thoseskilled in the art. Like numbers refer to like elements throughout the description.

Fig. l shows an example of a power tool l. The power tool l may for example be a nutrunner. The power tool l has a tool head 3 and a main body 5. The tool head 3 is attached to the main body 5. the tool head 3 In the present example,is removably attached to the main body 5. Thetool 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 l is operated, a user may grip the handle 7 to hold the power tool l.

Fig. 2 shows a close-up view of the power tool l.

According to the example, the tool head 3 has an endportion 3a that can be connected to the main body 5. Themain body 5 has an opening 5a configured to receive the end portion 3a.

The main body 5 is herein also referred to as a "firststructure". The tool head 3 is herein also referred to as a "second structure".

The main body 5 is provided with a first coil structure9. The first coil structure 9 is in the present examplearranged on a first surface of the main body 5. The firstsurface 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 l.

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

The second coil structure ll may extend along the circumferential direction of the power tool l.

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

Fig. 3 shows a detail of a longitudinal section of thepower tool l when the tool head 3 has been assembled with3 shows the interface between the the main body 5. Fig. main body 5 and the tool head 3. The end portion 3a ofthe tool head 3 extends into the main body 5. In theexample, an airgap l3 is provided between the main body 5and the end portion 3a. The first coil structure 9 and the second coil structure ll are configured to 1O 11 electromagnetically interact with each other over the airgap 13.

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

The first screen 15 may be a first ferrite sheet. Thefirst screen 15 may be mechanically flexible to allow itto 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 arrangedbetween the second coil structure 11 and the second surface of the tool head 3. The second screen 17 isconfigured 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. Thesecond screen 17 may be mechanically flexible to allow itto 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 firstcoil structure 9 and the second coil structure 11.According to this example, the power tool 1 comprises afirst flexible substrate 21 on which the first coilstructure 9 is printed. The first flexible substrate 21and the first coil structure 9 form a first flexible(PCB) 19. printed circuit board The first flexible PCB 19 is folded to follow the first surface of the main body 5. 12 The power tool l comprises a second flexible substrate 25on which the second coil structure ll is printed. Thesecond flexible substrate 25 and the second coilstructure ll 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 structure9 is a single coil and the second coil structure ll is a single coil.

Fig. 5 shows another example of the first coil structure 9 and the second coil structure ll. In this example the first coil structure 9 is a rectangular coil seen to theleft in Fig. 5 which is folded to follow the main body 5 in the circumferential direction of the power tool l. Therectangular coil may have a short side 27 and a long side29. The rectangular coil is folded along its long side 29.

The second coil structure l is a rectangular coil foldedto follow the tool head 3 in the circumferential direction of the power tool l. The rectangular coil mayhave 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 l comprises a power transfer circuit 3l and a demodulator circuit 33. The power transfer circuit 3l and the demodulator circuit areelectrically 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 3l and the demodulator circuit 33. 13The power tool l comprises a modulator circuit 35. Themodulator circuit 35 is electrically connected to the second coil structure ll.

The power tool l may also comprise a circuit 37. Thecircuit 37 may for example be a transducer such as atorque transducer, an angle sensor or a force measurementsensor. The circuit 37 may alternatively or additionallycomprising processing circuitry, for example to processmeasurements by the torque transducer, angle sensor, or fOICG ITIGâSUIGITIGÛÉ SGDSOI.

The circuit 37 is electrically connected to the secondcoil structure ll. 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 providewireless power transfer to the second coil structure ll.The first coil structure 9 is configured to induce thepower signal in the second coil structure ll which can power the modulator circuit 35 and optionally the circuit 37.

The power transfer circuit 3l may for example comprise switching circuit, such as a flyback converter, an H- bridge or a class-E amplifier. The switching circuit isconfigured to generate the power signal by switching a voltage, which when induced in the second coil structurell can drive the modulator circuit 35 and optionally the circuit 37. 14 The modulator circuit 35 is configured to receivedata/signals from the circuit 37 and to modulate thedata/signals to generate a modulated signal. Thedata/signals may for example be measurements by thecircuit 37 and/or an identifier of the type of tool head,and/or calibration data related to the tool head 3 for acontroller configured to operate the power tool l. Themodulator circuit 35 is configured to energise the secondcoil structure ll with the modulated signal to induce the modulated signal in the first coil structure 9.

The modulator circuit 35 may for example be configured toperform modulation using ASK modulation. The ASK modulation may for example OOK modulation.

The demodulator circuit 33 is configured to demodulatethe modulated signal when it has been induced in thefirst 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 beprovided with a modulator circuit and the tool head mayalso 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 datatransfer may be performed simultaneously by shifting thefrequency of the modulated signal away from that of thepower signal. For example, the frequency of the modulatedsignal may be of the order lO or higher than thefrequency 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 frequencyof the power signal. The high pass filter may be providedin 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 l. This example is similar to the one shown in Fig. 6. The firstcoil structure 9 however includes a first power transfercoil 9a and a separate first data transfer coil 9b. Thefirst power transfer coil 9a is electrically connected tothe power transfer circuit 31. The first data transfercoil 9b is electrically connected to the demodulator circuit 33.

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

The second coil structure ll includes a second powertransfer coil lla and a separate second data transfer coil llb.

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

The second power transfer coil lla is configured toinductively interact with the first power transfer coil9a. The first power transfer coil 9a is configured toinduce the power signal in the second power transfer coil lla.

The second data transfer coil llb is configured to inductively interact with the first data transfer coil 16 9b. The second data transfer coil llb is configured toinduce the modulated signal in the first data transfer coil 9b.

The second data transfer coil llb is configured to beelectrically connected to the modulator circuit 35. Themodulator circuit 35 is configured to energise the second data transfer coil llb with the modulated signal.

The second power transfer coil lla is configured to beelectrically connected to the modulator circuit 35 forpowering the modulator circuit 35 by means of the powersignal induced in the second power transfer coil lla by the first power transfer coil 9a.

The second power transfer coil lla and the second powertransfer coil llb may both be printed on the second flexible substrate.

According to one alternative, the main body may also beprovided with a modulator and the tool head may also beprovided with a demodulator circuit. In this way, two-waycommunication 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 structuremay form part of either the main body or the tool head.the For example, first structure may be a stationary part of the main body, and the second structure may be arotatable member. Data may thereby be transmittedwirelessly between the rotatable member and the stationary part. 17 The inventive concept has mainly been described abovewith reference to a few examples. However, as is readilyappreciated by a person skilled in the art, otherembodiments than the ones disclosed above are equallypossible within the scope of the inventive concept, as defined by the appended claims.

Claims

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

2. The power tool (1)(15)(17) as claimed in claim 1, wherein the first screen is a first ferrite sheet, and the second screen is a second ferrite sheet. 19

3. The power tool (l) as claimed in claim l or 2, whereinis arranged concentrically (ll). the first coil structure (9) with the second coil structure

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

5. The power tool (l) as claimed in any of claims l-3, comprising a first flexible substrate (21) wherein thefirst coil structure (ll)(21), (19) is printed on the first flexible substrate forming a first flexible printed circuit board, PCB, 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 (l).

6. The power tool (l) as claimed in claim 5, comprising a second flexible substrate (25) wherein the second coil structure (ll) is printed on the second flexiblesubstrate (25), forming a second flexible printed circuitboard, 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 (l) as claimed in claim 6, wherein thefirst coil structure (9) (98) comprises a first power transferand a separate first data transfer coil (9b) (ll) coil and the second coil structure comprises a second (lla) configured to inductively (9a), power transfer coil interact with the first power transfer coil and a separate second data transfer coil (llb) configured to inductively interact with the first data transfer coil (9b).

8. The power tool (l) 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 (ll) with the modulated signal toinduce the modulated signal in the first coil structure (9).

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

10. The power tool (l) as claimed in claim 8 or 9, comprising a power transfer circuit (3l) configured to energise the first coil structure (9) with a power signal to induce the power signal in the second coil structure (ll) to power the modulator circuit (35).

11. ll. The power tool (l) as claimed in claim lO, wherein the power transfer circuit (3l) comprises a switching circuit configured to switch the voltage across the first coil structure (9) to generate the power signal.

12. The power tool (l) as claimed in any of the preceding claims, comprising a main body (5) and an configured to be (5), interchangeable gear attachment (3) removably attached to the main body wherein the 21 second structure (3) is the interchangeable gear attachment.

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

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