FIELD OF THE INVENTION

The present invention relates to a wire reel hub, and particularly to a wire reel hub for supporting a wire reel in a welding system comprising a wire feeder comprising a wire reel hub support means for supporting the wire reel hub.

BACKGROUND OF THE INVENTION

A purpose of a welding wire feeder is to support a welding wire reel and to feed the welding wire to a welding gun. The wire feeder is provided with a wire driving means comprising rollers for driving the wire from the wire reel to the weld- ing gun. The excessive rotation of the wire reel is usually limited by a frictional brake adjusted by user.

A problem with the traditional wire feeder is that if the wire reel is heavy, due to the inertia of the heavy reel, it might be difficult to get into a rotating motion. While driving the welding wire, the rollers of the wire driving means may even cause damage to the welding wire. On the other hand, when welding work ends and wire driving means stops, the mass of the wire reel causes unwanted unwinding of the welding wire if the frictional brake is not adjusted correctly.

Another problem with the traditional wire feeder is that it only allows unwinding of the welding wire from the wire reel. After finishing with the welding job, the unwound and unused wire must be rewound by hand. Also, when the welding job is paused, due to the inertial rotation of the wire reel, the welding wire is left loose. This may cause unevenness in the weld.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a wire reel hub so as to over- come the above problems.

The object of the invention is achieved by a wire reel hub which is characterized by what is stated in the independent claim. The preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of providing a wire reel hub for supporting a wire reel in a welding system comprising a wire feeder comprising a wire reel hub support means for supporting the wire reel hub, the wire reel hub comprising a static part being adapted to be connected unrotatably to the wire reel hub support means,

a rotatable part connected rotatably to the static part,

an electric motor connected to the static part and to the rotatable part for con- trolling rotation of the rotatable part in relation to the static part,

a power supply means for powering the electric motor, and

a receiving means for receiving a wire reel coaxially with the wire reel hub.

An advantage of the wire reel hub of the invention is that the wire reel hub rotates the wire reel in the wire feeder for unwinding the welding wire and thus reduces the need for rotating the wire reel using the wire driving means. This reduces the risk of damaging the welding wire.

Another advantage of the wire reel hub of the invention is that it allows rewinding of the welding wire back to the wire reel especially after the welding work. The wire reel hub of the invention can also act as a brake for the wire reel when the operation of the motor is timely controlled by the welding device. The wire reel hub of the invention allows keeping the welding wire at desired tightness without adjustments by user and regardless of the changing mass of the reel, and thus reducing the unevenness caused by slack in the welding wire.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which

Figure 1 is a side view of a wire reel hub according to an embodiment of the invention;

Figure 2 is a front view of a wire reel hub according to an embodiment of the invention;

Figure 3 is a schematic cross section of a wire reel hub according to an embodiment of the invention;

Figure 4 is a schematic drawing of a wire reel hub connected to a wire feeder according to an embodiment of the invention;

Figure 5 is a schematic drawing of a top loaded wire feeder; and Figure 6 is a schematic drawing of a wire reel hub connected to a wire feeder according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a wire reel hub 10 for supporting a wire reel 20 in a welding system comprising a wire feeder 80 comprising a wire reel hub support means 30 for supporting the wire reel hub 10, the wire reel hub 10 comprising a static part 13 being adapted to be connected unrotatably to the wire reel hub support means 30,

a rotatable part 14 connected rotatably to the static part 13,

an electric motor 40 connected to the static part 13 and to the rotatable part 14 for controlling rotation of the rotatable part 14 in relation to the static part 13,

a power supply means 50 for powering the electric motor 40, and

a receiving means 17 for receiving a wire reel 20 coaxially with the wire reel hub 10.

The wire reel 20 comprises a frame usually made from plastic or metal wire. The frame has a hole for receiving a wire reel hub 10 supporting the wire reel 20 in a wire feeder 80. The hole defines a rotational axis of the wire reel 20.

With the power supply means 50 it is meant any means for supplying power to the electric motor 40. For example the power supply means 50 is an electric wiring connected to a power source.

The electric motor 40 is preferably controlled by a welding power source or a welding wire feeder 80 so that the operation of the motor 40 depends on the welding work functions. For example, when welding is started, the motor 40 aids to unwind the welding wire together with a wire driving means 81 comprised in the wire feeder 80. During welding the motor 40 is typically inactive, and only the internal friction of the motor resists unwinding causing the welding wire to have desired tightness. When welding ends and the wire driving means 81 stops, the motor 40 is controlled to prevent unwinding of the wire reel 20 by causing opposite force to the rotating wire reel 20. According to an embodiment the receiving means 17 is formed by the rotatable part 14. In other words the wire reel 20 is received on the rotatable part 14 and it is supported by the rotatable part 14.

According to an embodiment the wire reel hub 10 further comprises a rotation locking means 60 for preventing rotation of the wire reel 20 in relation to the rotatable part 14. According to an embodiment the rotation locking means 60 comprises a peg arranged at the rotatable part 14. The peg is arranged to couple with the wire reel 20.

According to an embodiment the electric motor 40 is at least partly enclosed by the wire reel hub 10. According to an embodiment the electric motor 40 is at least partly enclosed by the static part 13.

According to an embodiment the wire reel hub 10 comprises a first tubular member 15 and a second tubular member 16 arranged at least partly coaxially with the first tubular member 15 and supported by the first tubular member 15, wherein the static part 13 is at least partly formed by the first tubular member 15 and the rotatable part 14 is at least partly formed by the second tubular member 16.

According to an embodiment the wire reel hub 10 comprises an axial locking means 70 for preventing axial movement of the wire reel 20 in relation to the wire reel hub 10. According to an embodiment the axial locking means 70 comprises a flange 71 arranged to the rotatable part 14, an external thread 73 arranged to the rotatable part 14 and a nut 72 attachable to the thread 73 for retaining the wire reel 20 between the flange 71 and the nut 72.

According to an embodiment the electric motor 40 has been adapted rotate to rotatable part 14 in relation to the static part 13 and/or to inhibit rotation of the rotatable part 14 in relation to the static part 13. In other words the electric motor 40 is able to rotate the rotatable part 14 in clockwise direction or in counter clockwise direction in relation to the static part 13 or to act as a brake for the rotatable part 14 in relation to the static part 13.

According to an embodiment the wire reel hub 10 is used in a side loaded wire feeder, i.e. a wire feeder 80 which is openable from the side of the wire feeder 80 for accessing and replacing the wire reel 20. This kind of wire feeder 80 is illustrated in Figure 4. According to an embodiment the static part 13 is fixed to the wire reel hub support means 30. Preferably the static part 13 is bolted or welded to the wire reel hub support means 30.

According to an embodiment the wire reel hub 10 is used in a top loaded wire feeder, i.e. a wire feeder 80 which is openable from the top of the wire feeder 80 for accessing and replacing the wire reel 20. This kind of wire feeder is illustrated in Figures 5 and 6. According to an embodiment the static part 13 is re- leasably connectable to the wire reel hub support means 30.

According to an embodiment the wire reel hub support means 30 comprises a first support 31 and a second support 32 and that the wire reel hub 10 com- prises a first end 1 1 and a second end 12 opposite the first end 1 1 , the static part 13 being connected unrotatably to the first end 1 1 , wherein the first end 1 1 is configured to be supported by the first support 31 and the second end 12 is configured to be supported by the second support 32. Preferably the first end 1 1 is configured to be supported unrotatably by the first support 31 . According to an embodiment the first support 31 comprises a slot and the first end 1 1 is arranged to form a positive lock with the slot for preventing rotation of the first end 1 1 in relation to the first support 31 .

According to an embodiment the power supply means 50 comprise electric connectors 51 for connecting with corresponding electric connectors of the wire reel hub support means 30. According to an embodiment the electric connectors 51 are arranged at the first end 1 1 . According to an embodiment the electric connectors 51 are arranged at the static part 13.

According to an embodiment the corresponding electric connectors are arranged at the first support 31 . According to an embodiment the corresponding electric connectors are arranged at the first support 31 and the second support 32. This way the wire reel hub 10 can be positioned in the wire reel hub support means 30 in both orientations, i.e. the first end 1 1 can also be supported by the second support 32.

The invention also relates to a wire feeder 80 for feeding welding wire in a welding system, the wire feeder 80 comprising a wire reel hub 10 as described above. Preferably the wire feeder 80 further comprises a wire driving means 81 for driving the welding wire from the wire reel 20 to a welding gun. According to an embodiment the wire driving means 81 is separate from the wire reel hub 10. For example the wire driving means comprises two rotatable rollers for re- ceiving a welding wire therebetween.