Sheath attachement in particular for a welding torch having a spherical joint for connection to power cable

Abstract: A sheath attachment for a welding torch, comprising a sleeve (5) having a spherical head (3) to be inserted into a seating in the handle of the torch, with a ring nut (9) slidably mounted on said sleeve (5), means being provided for sliding said ring nut (9) along the axis of the sleeve in order to clamp a sheath (2), inserted on the sleeve (5), against a flange (4) provided at the end of the sleeve itself. Preferably said ring nut (9) is provided with at least an inwardly protruding tooth (10), preferably two inner opposite teeth, and a hollow portion is provided on the surface of the sleeve (5), between said flange (4) and said spherical head (3), said hollow portion being delimited by inclined raised walls (7) engaged by the tooth (10) of the ring (9), so that the rotating movement of the ring (9) causes an axial displacement of the ring along the sleeve (5).

Description: The present invention relates to a sheath attachment in particular for a welding torch having a spherical joint for connection to power cable, characterised in that it is provided with quick connection means for clamping a cable sheath. In particular the invention provides quick fastening means which ensure the clamping of the feeding cable or, more precisely, of its sheath, avoiding any possible unfastening and detaching, thus making the welding tool easier and handy to use. Said clamping means comprise a cylindrical body which, at one end, is provided with a spherical joint for engaging the welding torch handle and, at the other end, is provided with an inclined wall, engaged by a ring nut provided with inner teeth which cooperate with a slot in the cylindrical body to clamp the sheath. Several solutions and accessories for the welding torches are already known in the welding field; said torches are connected to a current generator by means of a feeding cable. Said feeding cable, during the work of the tool, connects the handle of the welding torch to an attachment or feeding joint on the generator, in order to feed the tool with the current, the control signals, the gas and whatever is necessary for its operation. The feeding cable usually comprises several components protected by a sheath; for instance, a feeding cable for the welding current, cne or more cables bringing the signals from the torch to the generator, a pipe for feeding a gas and, if required, feeding pipes for a cooling fluid. Since the bundle of the feeding cable is quite thick, quite bulky and not very flexible and, as a consequence, not suitable to follow the movements of the welding torch, the use of a spherical joint has already been proposed, which makes the torch free to move with respect to the cable to which it is connected. Document FR-A-2720019, for example, discloses a sheath attachment for a welding torch comprising a sleeve with a spherical head, in order to make the torch free to move with respect to the cable. On one hand such spherical joint solved the problem arising from the torch stiffness with respect to the feeding cable, but on the other hand it improved some difficulties relating to the connection and clamping of the sheath. In accordance with a first known solution, some bands locked by means of screws are used, in order to fasten the sheath to the sleeve of the spherical joint. The bands, however, are difficult to apply, due to the fact that fastening can only be achieved by using tools, such as screwdrivers or the like, and moreover there is a difficulty in handling the torch, because of the overall dimensions of the projecting parts of the band. Moreover, document US-A-4544827, which represents the closest prior art, discloses a sheath attachment for a welding torch comprising a sleeve, wherein a ring nut is slidably mounted on said sleeve, means being provided for sliding said ring nut along the axis of the sleeve in order to clamp or sheath inserted on the sleeve against a flange provided at the end of the sleeve itself. The object of the invention is to remedy the drawbacks due to the low efficacy of the known clamping means used in spherical joints to connect the welding torch and the feeding cable, by providing a new fastening device, which comprises an annular coupling of the ring-flange type, as well as means for making the ring shift along the sleeve for clamping the sheath. According to the invention, one or more pins are provided which are integral with the ring nut and which engage an inclined wall on the sleeve, to cause the shifting of the collar. The invention relates to a joint for welding torches or the like according to the present claim 1. Further advantages and features of the invention could be better understood from the following description of a non restrictive embodiment. In the specification reference is made to the enclosed drawings in which: fig. 1 is an exploded view of the joint in accordance with the invention shown as a whole; fig. 2 shows a sectional view of the ring, showing the inner teeth; fig 3 is a schematic view of the joint in a first side view; fig 4 is a schematic view of the joint in a second side view; fig 5 schematically shows the joint in accordance with the invention, during the insertion of a sheath; fig 6 is a view of the joint of the invention, after the insertion of a sheath; With reference to the enclosed drawings, numeral 1 indicates as a whole a joint for connecting a feeding cable to the handle of a welding torch, not shown since it is of a known type. Numeral 2 indicates the sheath of the feeding cable. The joint 1, preferably made of plastic materials, comprises a spherical head 3 and a cylindrical hollow body or sleeve 5, which ends with a flange edge 4, chamfered to make easier the insertion of the sheath 2. The invention is characterized in that a hollow portion is provided on the outer wall of the sleeve 5, in an area comprised between the spherical head and the flange 4. Said hollow portion is delimited by a raised portion 6, defining a wall 7 which is inclined with respect to a plane orthogonal to the axis of the sleeve. Two axial slots 8, opposite to each other, are provided on the sleeve 5 of the joint, and split the sleeve itself into two symmetrical parts, facing each other. The inclined walls 7 are also symmetrical. The described parts are engaged by a ring nut 9, which is cylindrical, hollow shaped, and is provided with a couple of inner teeth 10 facing each other. The ring 9 is the clamping element for the sheath 2 of the cable, said sheath being inserted onto the sleeve, wrapping the annular flange 4. The damping of the sheath 2 is obtained by rotating the ring nut 9 to a certain extent, so that the engagement of the teeth 10 with the inclined walls 7 of the raised portion 6 causes a thrust of the edge of the ring nut against the flange 4. The ring nut 9 damps the sheath against the flange 4, without the need of further operations. It is to be noted that in order to lock the sheath it is sufficient to rotate the ring along a quarter-turn or half a turn. Advantageously stop means, such as teeth 11, are provided at the end of each inclined wall 7 to limit the rotation of the ring 9 and its thrust against the flange 4. As it will be apparent from the foregoing, the invention permits to clamp the sheath on the sleeve without the use of any tool, avoiding the presence of cutting elements, such as bands, which could damage the sheath. Those skilled in the art could provide several modifications to what has been described and shown as a non restrictive example and some parts could be changed by any other technical equivalents, all of which fall within the scope of the present invention as defined in the appended claims.

Claims: A sheath attachment for a welding torch, comprising a sleeve (5) having a head (3) to be inserted into a seating in the handle of the torch, wherein a ring nut (9) is slidably mounted on said sleeve (5), means being provided for sliding said ring nut (9) along the axis of the sleeve in order to clamp a sheath (2), inserted on the sleeve (5), against a flange (4) provided at the end of the sleeve itself, characterised in that said head (3) is spherical, and said ring nut (9) is provided with at least an inwardly protruding tooth (10), preferably two inner opposite teeth, a hollow portion being provided on the surface of the sleeve (5) between said flange (4) and said spherical head (3) and said hollow portion being delimited by inclined raised walls (7) engaged by the tooth (10) of the ring (9), so that the rotating movement of the ring (9) causes an axial displacement of the ring along the sleeve (5). A sheath attachment for a welding torch, provided with quick clamping means according to claim 1, wherein two opposite slots (8) are provided in said sleeve (5) of the joint, said slots splitting the sleeve (5) into two symmetrical and facing parts, said slots also splitting the inclined walls (7) into two symmetrical parts. A sheath attachment for a welding torch provided with quick fastening means according to claim 1, wherein the clamping of the sheath (2) is obtained by rotating said ring nut (9) to a certain extent, so that the pressure of the teeth (10) against the inclined walls (7) causes the thrust of the edge of the ring (9) against the flange (4).

Inventors: ZIGLIOTTO GIUSEPPE, ZIGLIOTTO, GIUSEPPE
Applicants: TRAFIMET SPA, TRAFIMET S.P.A.
Application year: 2000
Main classification: B23K9
IPC codes: B23K37, B23K9