Patent ID: 12257702

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the embodiments, wherein other parts may be omitted. Like reference numerals refer to like elements throughout the description.

DETAILED DESCRIPTION OF EMBODIMENTS

As illustrated inFIG.1, a system1according to an embodiment comprises an industrial robot2and an end effector5to be operated by the robot2. The system1may be automated and capable of movement on at least one, but preferably two or more axes. For example, the system1may be adapted to be used for manufacturing, such as for assembling parts.

The industrial robot2may comprise a robot arm16, which may have one or more joints17for enabling movement of the robot arm16around one or more axes. A robot arm end portion3is provided at the distal end of the robot arm16. The industrial robot2further comprises a power supply circuit4arranged to supply current to the robot arm end portion3. The power supply circuit4may e.g. draw current from the mains. The power supply circuit4may comprise, or be connected to, a control device9for the industrial robot2. The control device9may be configured to control the power supply circuit4. For example, the industrial robot2may be stationary and may be arranged to be placed along an assembly line.

The end effector5is attached to the robot arm end portion3and comprises a power tool6and an accumulator module7arranged to power operation of the power tool6. The power tool6may e.g. be some kind of tightening tool, riveting tool, or drill.

The accumulator module7may e.g. comprise a battery, a capacitor or any other kind of means for accumulating energy to be used for powering the tool6.

For example, the end effector5may comprise a holder11arranged to hold the power tool6. The holder11may be the part of the end effector5that is attached to the robot arm end portion3. The power tool6may be mounted to the holder11. Alternatively, the holder11may be integrated with the power tool6. For example, the accumulator module7may be attached to/comprised in the holder11as illustrated inFIGS.1and2, or be attached to/comprised in the power tool6(not shown).

The end effector5further comprises a charger8arranged to draw current from the power supply circuit4at the robot arm end portion3and to supply charging current to the accumulator module7. An electrical connection may be provided between the power supply circuit4at the robot arm end portion3and the charger8in the end effector5so as to supply current there between for enabling charging. The charger8may comprise an electrical contact15adapted to mate with an electrical contact14of the accumulator module7(seeFIG.2). During operation, current flows from the power supply circuit4to the end effector5and its' charger8, and then from the charger8to the accumulator module7. Preferably, the accumulator module7may be connected (and attached) to the charger8during operation of the system1, including operation of the power tool6.

The system1may further comprise a control device10configured to control the charging of the accumulator module7by the charger8. The control device10may be arranged in the end effector5, such as in the holder11as illustrated inFIG.1, or in the power tool6(not shown). Alternatively, the control device10may be arranged in the industrial robot2, such as in (or in connection to) the control device9for the power supply circuit4.

Turning now toFIG.2, embodiments of the system1will be described in more detail. For example, the holder11may comprise a charger portion18including the charger8and arranged to hold the accumulator module7. A cable12may provide the charger portion18with power from the power supply circuit4in the robot arm end portion3. The cable12may be routed outside or inside (the latter not shown) the robot arm end portion3and the end effector5. The end effector5may comprise circuitry for providing power from the accumulator module7to the power tool6. For example, a cable13may provide the power tool6with power from the charger portion18.

According to an embodiment, the charging current for charging the accumulator module7may be just a fraction of the peak current that is consumed by the power tool6during its operation. The power tool6may typically require a peak current around 15-30 A when operated while the charging current may be limited to around 0.5-3 A. For example, the charging current may be less than ⅓rdof the peak current consumed by the power tool6during its operation, such as less than ⅕thof the peak current consumed by the power tool6during its operation.

For example, the accumulator module7may have a capacity that can provide the power tool6with its peak current during operation. The accumulator module7may e.g. comprise a 18, 24, 36 or 48 V battery.

According to an embodiment, the control device9may be configured to control the charging of the accumulator module7such that the charging current is kept below a (preset or dynamic) threshold being lower than the total available current from the power supply circuit4. Hence, the charging of the power tool6may only utilize some of the available current from the industrial robot2, thereby enabling some of the current available from the industrial robot2to be utilized for other purposes.

The power tool6may be charged only between operations of the power tool6, or simply continuously as long as the charging level of the accumulator module7is below a certain (preset) threshold.

The control device10may be configured to control the charging level of the accumulator module7to be below a (preset) maximum threshold and optionally also above a (preset) minimum threshold. This may be referred to as the state of charge window of the accumulator module7. The state of charge window may e.g. have a lower threshold comprised within a range of 20-40% of the maximum charge capacity. The upper threshold may be comprised within a range of 60-80% of the maximum charge capacity. As the accumulator module7can be continuously charged in the end effector5, the state of charge window may be kept relatively small, which is beneficial for the accumulator module7health.

According to an embodiment, the control device10may be configured to provide a warning signal in response to the charging level of the accumulator module7falling below a minimum threshold and/or exceeding a maximum threshold. An operator of the system1may then be notified that charging of the accumulator module7has not been performed as excepted. The warning signal may e.g. be a visual signal and/or an audio signal.

The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.