EP4670236A1

EP4670236A1 - Rotation-independent electrical coupling device and method for electrically connecting a first conductor to a second conductor

Info

Publication number: EP4670236A1
Application number: EP24714040.3A
Authority: EP
Inventors: Finn Inge Langeland
Original assignee: Zinus AS
Current assignee: Zinus AS
Priority date: 2023-02-21
Filing date: 2024-02-21
Publication date: 2025-12-31
Also published as: WO2024177512A1; NO348170B1; NO20230173A1

Abstract

The invention relates to a rotational position independent electrical coupling apparatus (10), for coupling a first conductor (30) to a second conductor (20), wherein the electrical coupling apparatus (10) comprises: - an electrical conducting disk (12), being rotatable, the second conductor (20) is terminated in the disk (12), and - an electrical conducting clamp (13), movable between a clamp on position where the clamp (13) is clamping on the disk (12) and a clamp off position where the clamp (13) is not in contact with the disk (12), the first conductor (30) is terminated in the clamp (13). The invention also relates to a cable drum and a method for coupling a first conductor to a second conductor.

Description

TITLE: ROTATIONAL POSITION INDEPENDENT ELECTRICAL COUPLING APPARATUS AND METHOD FOR FOR ELECTRICALLY CONNECTING A FIRST CONDUCTOR TO A SECOND CONDUCTOR

Field of the invention

The invention relates to a rotational position independent electrical coupling apparatus, a cable drum and a method for electrically connecting a first conductor to a second conductor.

Background of the invention

Supplying electrical current to, from or via objects rotating is commonly solved using a slip ring assembly. Slip ring assemblies enables rotation of a electrical coupling while electrical current is transmitted and is typically used in applications such as electric motors and generators. In a typical slip ring assembly electrical current is transferred via brushes (one for each lead/conductor) touching rotating rings (one for each lead/conductor). Slip ring assemblies are relatively complex and expensive. They are prone to wear and tear and they can be damaged if high currents are transmitted over time while the slipring is not rotating.

Prior art:

CN218415287U relates to a high-performance motor slip ring.

KR20110032744 A relates to a double cable reel which establishes the slip ring apparatus in the rotary shaft of each drum.

Object of the invention

It is an object of the invention to provide an alternative electrical coupling. In particular, an electrical coupling that is suitable for use with rotating machines and devices.

It is also an objective to provide a robust and durable electrical coupling that can transmit high loads and is easy to operate. It is also an objective to provide a solution for transmitting electrical current via a electrical copling that can rotate and wherein the rotating coupling is suitable for transmitting current while the electrical coupling is stationary (i.e. while it is not rotating).

Summary of the invention

In one aspect the invention relates to a rotational position independent electrical coupling apparatus, for coupling a first conductor to a second conductor. The electrical coupling apparatus comprises:

- an electrical conducting disk, being rotatable, the second conductor is terminated in the disk, and

- an electrical conducting clamp, movable between a clamp on position where the clamp is clamping on the disk and a clamp off position where the clamp is not in contact with the disk, the first conductor is terminated in the clamp.

Compare to a slipring assembly the rotational position independent electrical coupling apparatus is more suitable for transferring electrical current while a rotating machine/apparatus is not rotating. The rings of a slip ring device can disform, due to heat, if the slip ring is stationary so that the rings contacts the brush at the same point for a long period of time. Eventually the surface of the slip ring will be uneven and the contact between the brushes and the rings can be affected and hence the ability to transferred electricity. Also slip ring assemblies are more complex, expensive and fragile devices.

The advantage over other electrical couplings not being a slip ring, is that the two mating contact points (in this case the disk and the clamp) can be put into contact with each other without having to orient them relative to each other. The same relative movement between the contact points can be used to put them into contact no matter what rotational position the device is in at a given time. This will for instance makes an automated or remotely controlled operation of the electrical coupling easier.

The disk is preferably a circular disk. The disk can be arranged with a central hole wherein the axle is passed through the central hole or the disk is connected to the axle at an end of the axle. The electrical conducting disk can be coaxially connected to an axle, the axle being rotatable.

The clamp can comprise a copper alloy.

The disk can comprise a copper alloy.

The clamp can be a U-shaped clamp arranged to slide radially in onto the disk with the opening of the U-shape towards the radial center of the disk.

There can be two or more disks each connected to a second conductor and there can be one clamp for each disk and each clamp can be connected to a first conductor.

The apparatus can be arranged with more than one first and one second conductor. Normally there will be 3 or 4 second and first conductors but a higher number of conductors can easily be included by adding more disks and clamps.

When there are more than one clamp and disk the clamps are arranged so that the second clamp has its clamp on position 180° offset (+/- 10°) (i.e. on the opposite side of the axle) from another clamps clamp on position. This is to avoid side load on the axle when the clamps are pushed in on the disk. So, the clamps are preferably arranged in pairs arranged opposite each other relative to the axle to avoid side load on the axle when alle the clamps are moved to their clamp on position simultaneously. For even numbers of clamps and disks there will be pairs for odd numbers there will be one clamp not having an opposite clamp.

When there is a plurality of clamps and disks it is also space saving to arrange the neighboring clamp so it moves towards the axle from a different angle, i.e. the disks can be arranged axially closer to each other.

The axle can be coaxially connected to a cable drum for winding up the second conductor on the cable drum or the axle can comprise an axial section arranged for winding up the second conductor. The clamp can be arranged on a pivotable arm so that the clamp and the arm is pivotable between the clamp on position and the clamp off position.

The arm can be operated manually or by an actuator controlled by a control system. When there are more than one clamp and disk there can be one arm arranged on each side of the axle. Each arm can hold a rack holding several clamps.

In another aspect the invention relates to a cable drum for an electrical cable. The cable drum comprises the electrical coupling apparatus as disclosed above. The cable drum is coaxially connected to the axle of the electrical coupling apparatus.

The electrical coupling is particularly suitable for a cable drum, but other types of rotating electrical apparatuses and devices can also use the electrical coupling. Normally a cable on a cable drum is only conducting electrical current when the cable drum is not rotating. Typically, the cable winded up on the cable drum is pulled out to the appropriate length to reach an electrical consumer and then the electrical consumer is supplied with power through the cable of the cable drum. Having a slip ring assembly in a cable drum is unnecessarily complicated and expensive and the slip ring can over time get damaged if high currents are transmitted while the slip ring is not rotating. At the same time, it is desirable to be able to electrically connect, the end of the cable connected to the drum, to a mating connector without having to adjust the rotational position of the drum or without having to adjust the mating electrical connector to the position of the drum.

The cable drum can be supported by a rack and the clamp(s) can be arranged on an pivotable arm, being pivotable around a pivot point on the rack, so that the clamp and the arm is pivotable between the clamp on position and the clamp off position.

In yet another aspect the invention relates to a method for electrically connecting a first conductor to a second conductor, wherein the method comprises the steps of: a) providing a rotational position independent electrical coupling apparatus, comprising:

- an axle, being rotatable,

- an electrical conducting disk, coaxially connected to the axle, the second conductor is terminated in the disk, and - an electrical conducting clamp, the first conductor is terminated in the clamp, b) stopping the rotation of the axle, if the axle is rotating, c) moving the clamp to a clamp on position, wherein the clamp is clamping on the disk, so that electrical current is being transferred between the first conductor and the second conductor via the clamp and the disk, d) moving the clamp from the clamp on position to a clamp off position wherein the clamp is not in contact with the disk, so that electrical current no longer is transferred between the first- and the second electrical conductor and e) rotating the axle.

The rotatable axle is the axle of a cable drum, and wherein rotating the axle in step e) includes spooling out or in a cable comprising the second conductor.

Description of the diagrams

Fig. 1 shows schematically the principle of an embodiment of the invention.

Fig. 2a shows an embodiment of the disk and the clamp in a clamp off position

Fig. 2b shows an embodiment of the disk and the clamp in a clamp on position Description of preferred embodiments of the invention

In the following embodiments of the invention will be described with reference to the figures.

Fig. 1 shows schematically an embodiment of a rotational position independent electrical coupling 10. The figures are striped for housing, support structure and the like that would be obvious for a person skilled in the art. Fig. 1 shows only the components needed to understand the principle of the electrical coupling apparatus

10.

In this embodiment the electrical coupling apparatus 10 comprises five disks 12 arranged on an axle 11 . The disk 12 has a hole in the center where the axle 11 is passed through and the disks 12 are fixed to the axle 11 . Five second electrical conductors 20 are connected to the axle 11 and each of the second conductors 20 are leaded via the axle 11 to one of the disks 12 where they are electrically terminated.

As seen in Fig. 1 five clamps 13 are clamped onto the disks 12, one to each disk 12. A first electrical conductor 30 is electrically terminated in the clamp 13. Three clamps 13 are clamped onto their disk 12 from one side and two clamps are clamped onto their disk 12 from the opposite side. Since the clamps 13 are clamping their disk 12 from different direction the disks 12 can be arranged closer to each other on the axle

11. Arranging clamps 13 on opposite sides of the axle 11 also reduces or eliminates the side load on the axle 11 when the clamps 12 simultaneously are pushed onto the disks 12.

The clamps 13 are as seen in the figures U-shaped. The two legs of the U-shape can act with a biasing force towards the disk 12 when in the clamp on position. The opening of the U-shape can be slightly wider than the rest of the clamp, so that the clamp 13 easily can hit the disk, and/or the disk 12 can be tapered towards the outer circumference. There can be one arm or a set of arms on each side of the axle 11. The clamps 13 can be arranged on a rack held by the arm(s). The arm(s) can pivot so that the clamps 13 can be moved by the arm between the clamp on position and the clamp off position. The arms can for instance be connected via a pivot point to the same frame or structure that supports the axle 11. The axle 11 can be a common axle to the electrical coupling and the cable drum. This arrangement is not displayed in the figures. Such an arrangement with pivoting arms is only one example of a mechanism for holding and moving the clamps. The clamps 13 could alternatively be moved linear towards and onto the disks 12, by an actuator.

Below is an example of a use of the electrical coupling and the associated operation. In this example the electrical coupling 10 is used with a cable drum. The first conductor(s) 30 is connected to an electrical supply. The second conductor(s) 20 are comprised in a cable having a distal end and a proximal end. The proximal end of the cable is connected to the cable drum. A typical operation will be to make sure the clamp(s) 13 are in the clamp off position. Then the appropriate length of cable is spooled off the cable drum to reach, for instance, an electrical consumer. Followed by connecting the distal end of the cable to the electrical consumer and move the clamps to the clamp on position to supply the electrical consumer with power. After use the electrical consumer can be disconnected from the distal end of the cable, the clamp(s) can be moved to the clamp off position and the cable can be spooled back onto the cable drum.

In another example the cable can transmit an electrical signal.

Fig. 2a and Fig. 2b shows the first conductor 30 terminated to the clamp 13 and the second conductor 20 terminated to the disk 12. In Fig. 2a the clamp 13 is in the clamp off position. In Fig. 2b the clamp 13 is in the clamp on position.

An embodiment of the invention can be described as a rotational position independent electrical coupling apparatus 10, for coupling a stationary first conductor 30 to a second conductor 20 attached to an axle 11 , wherein the electrical coupling apparatus 10 comprises:

- the axle 11, being rotatable,

- an electrical conducting disk 12, coaxially connected to the axle 11, the second conductor 20 is terminated in the disk 12, and

- an electrical conducting clamp 13, movable between a clamp on position where the clamp 13 is clamping on the disk 12 and a clamp off position where the clamp 13 is not in contact with the disk 13, the first conductor 30 is terminated in the clamp 12.

The above embodiment can be used for a cable drum, and said cable drum can be used for supplying construction machinery such as excavators with electrical power. It is desirable to replace todays diesel powered machines with electrical powered machines. To electrify a excavator for instance it would require a large expensive battery pack if the excavator was not plugged to the power grid (or other electrical supply). Keeping a construction machine plugged to the power grid can eliminate the use for a power pack or at least reduce the need for battery power, so that only a small battery pack is needed. However, plugging in the machine can limit the machines possibility to move around unless a slip ring or other more suitable solutions are used.

Supplying power to movable machinery can be done by a method for supplying electrical power to a movable machine. The method comprises the steps of: a) providing a first and a second cable drum each having the above disclosed electrical coupling 10, wherein the second electrical conductors 20 are comprised in a first and a second cable each having a proximal end connected to one of the cable drums and a distal end, b) connecting the first electrical conductors 30 to an electrical power supply, c) connecting the distal ends of the cables to the machine, d) operate the electrical couplings so that the one connected to the cable with the least slack is disengaged and the other is engaged, e) rotating the cable drum with the disengaged coupling to spool out addition cable (to create slack in the cable), f) operate both electrical couplings so that the previously disengaged coupling is engaged and the previously engaged coupling is disengaged, g) move the machine further away from the power supply until the cable of the cable drum with the coupling engaged is stretched out (having no more slack), h) repeat steps d) - g), while moving the machine further away from the power supply.

Steps b) and c) can also be done in the reverse order.

By saying that the electrical coupling is disengaged it is meant that the clamps are in the clamp off position. By saying that the electrical coupling is engaged it is meant that the clamps are in the clamp on position.

The method can be reversed to move the machine closer to the electrical power supply. Then it will be spooling in cable and keeping the cable drum with the least slack engaged, while spooling in cable on the disengaged cable drum with cable having the most slack.

By using this method the machine will always be connected to the source of power via one cable and one electrical coupling 10, while the other cable is spooled in or out.

Claims

1. Rotational position independent electrical coupling apparatus (10), for coupling a first conductor (30) to a second conductor (20), wherein the electrical coupling apparatus (10) comprises:

- an electrical conducting disk (12), being rotatable, the second conductor (20) is terminated in the disk (12), and

- an electrical conducting clamp (13), movable between a clamp on position where the clamp (13) is clamping on the disk (12) and a clamp off position where the clamp (13) is not in contact with the disk (12), the first conductor (30) is terminated in the clamp (13).

2. The electrical coupling apparatus (10) according to claim 1 , wherein the electrical conducting disk (12) is coaxially connected to an axle (11), the axle (11) being rotatable.

3. The electrical coupling apparatus (10) according to claim 1 or 2, wherein the clamp (13) comprises a copper alloy.

4. The electrical coupling apparatus (10) according to any of the preceding claims, wherein the disk (12) comprises a copper alloy.

5. The electrical coupling apparatus (10) according to any of the preceding claims, wherein the clamp (13) is a U-shaped clamp arranged to slide radially in onto the disk (12) with the opening of the U-shape towards the radial center of the disk (12).

6. The electrical coupling apparatus (10) according to any of the preceding claims, wherein there are two or more disks (12) each connected to a second conductor (20) and wherein there is one clamp (13) for each disk and each clamp is connected to a first conductor (30).

7. The electrical coupling apparatus (10) according to any of the claims 2-6, wherein the axle (11) is coaxially connected to a cable drum for winding up the second conductor (20) on the cable drum or the axle (11) comprises an axial section arranged for winding up the second conductor (20).

8. The electrical coupling apparatus (10) according to any of the preceding claims, wherein the clamp (13) is arranged on an pivotable arm so that the clamp (13) and the arm are pivotable between the clamp on position and the clamp off position.

9. A cable drum for an electrical cable comprising the electrical coupling apparatus (10) according to any of the claims 2-6, and wherein a drum of the cable drum is coaxially connected to the axle (11) of the electrical coupling apparatus (10).

10. The cable drum according to claim 9, wherein the cable drum is supported by a rack and the clamp(s) (13) is arranged on an pivotable arm, being pivotable around a pivot point on the rack, so that the clamp (13) and the arm is pivotable between the clamp on position and the clamp off position.

11 . Method for electrically connecting a first conductor (30) to a second conductor (20), wherein the method comprises the steps of: a) providing a rotational position independent electrical coupling apparatus (10), comprising:

- an axle (11), being rotatable,

- an electrical conducting disk (12), coaxially connected to the axle (11), the second conductor (20) is terminated in the disk (12), and

- an electrical conducting clamp (13), the first conductor (30) is terminated in the clamp (12), b) stopping the rotation of the axle (11), if the axle (11) is rotating, c) moving the clamp (13) to a clamp on position, wherein the clamp (13) is clamping on the disk (12), so that electrical current is being transferred between the first conductor (30) and the second conductor (20) via the clamp (13) and the disk (12), d) moving the clamp (13) from the clamp on position to a clamp off position wherein the clamp (13) is not in contact with the disk (12), so that electrical current no longer is transferred between the first- (30) and the second electrical conductor (20), and e) rotating the axle (11).

12. The method according to claim 11 , wherein the rotatable axle (11) is the axle of a cable drum, and wherein rotating the axle (11) in step e) includes spooling out or in a cable comprising the second conductor (20).