Electric Spot Welding Head

Abstract

A spot welding head is described wherein an electrical conductor for connection of one electrode connection to an electric transformer is guided into a tubular sheath whose ends are rigidly connected to the rear ends of the supporting bodies of the electrodes. This tubular sheath defines a substantially stiff loop portion which is configured and arranged so as to be substantially parallel and facing the annular path defined by the two electrodes and the supporting bodies thereof, in such a way that the two magnetic fields, one generated by electromagnetic induction caused by electric current flowing through the electric conductor placed into the loop-shaped sheath, and the other generated by electromagnetic induction caused by electric current flowing through the electrodes and the supporting bodies thereof, substantially cancel each other out or anyway generate an overall magnetic field which is sensibly reduced and located forwardly with respect to the rear end of the welding head or anyway spaced forwardly away from the operator's body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will be described with reference to the attached drawings, purely by way of non-limiting example, wherein:

FIG. 1 is a perspective view of a welding head according to the known art,

FIG. 2 is a perspective schematic view of a welding head according to the invention,

FIG. 3 shows a further embodiment of the welding head according to the invention.

Claims

1. A spot welding head comprising: a pair of electrodes supported by respective supporting bodies and movable with respect to each other between an open position and a closed position,an actuator device to control the movement of the electrodes between the open position and the closed position,electric conductors connecting the two electrodes to the terminals of a transformer which is located at a remote position with respect to the welding head, anda tubular sheath portion, into which at least part of at least one of the aforesaid electrical conductors is guided, having a loop portion with ends rigidly connected to the rear ends of the supporting bodies of the electrodes,wherein said loop-shaped sheath is disposed in such a way that the magnetic field generated by electromagnetic induction caused by electric current flowing through the electric conductor placed into the loop-shaped sheath, and magnetic field generated by electromagnetic induction caused by electric current flowing through the two electrodes and through the supporting bodies of the two electrodes, generate-an overall magnetic field sensibly reduced and located forwardly with respect to the rear end of the welding head or anyway spaced forwardly away from the operator's body.

2. The spot welding head, according to claim 1, wherein said tubular sheath loop portion extends into a plane lying substantially parallel and side by side to the plane defined by the bodies of the two electrodes, said loop portion being substantially centered with respect to a median direction which is parallel and intermediate between the longitudinal directions of said electrode supporting bodies, so that the sheath loop portion faces the annular path defined by the electrodes and the supporting bodies thereof.

3. The spot welding head, according to claim 2, wherein the arrangement is such that the electric conductor placed into said loop portion is passed through by a current moving in a direction of rotation opposite to that of the current through the two electrodes.

4. The spot welding head, according to claim 1, wherein the welding head is provided with a protection shield on its rear side to protect the operator from any residual magnetic field generated by current flowing through the welding head.

5. The spot welding head, according to claim 1, wherein the loop-shaped sheath comprises two substantially rectilinear stiff extensions, parallel and spaced from each other, which at one end are connected together through a curved portion and at the other end are respectively connected to the rear ends of the electrode supporting bodies through two substantially stiff curved portions.

6. The spot welding head, according to claim 4, wherein said shield comprises aluminum.

7. The spot welding head, according to claim 1, wherein the magnetic field generated by the electric current flowing through the conductor placed into the loop-shaped sheath, and the magnetic field generated by the electric current flowing through the two electrodes and through the supporting bodies of the two electrodes, substantially cancel each other out.