Soldering Iron With Fume Suction Tube

The invention relates to a soldering iron equipped with means for removing by suction solder fumes created by resin incorporated in the solder, comprising a handle having an electrically heated element with an outer metal casing, a soldering tip connected to said element, and a metallic suction nozzle, one end of which nozzle lies in the proximity of the soldering tip and the other end of which is connected to a suction channel located in the handle, this suction channel in turn being connected to a flexible plastics hose connected to a suction source.

Such soldering irons are particularly suited for removing the irritating and often harmful fumes generated by the solder flux incorporated in the solder or used separately in conjunction therewith, this flux containing volatile resins. The most serious drawback with soldering irons of this kind is the relatively short time in which they can be used before needing to clean the nozzle and the suction channel. In normal soldering irons of this kind, nominally about 30 liters of air are drawn through the nozzle each minute, which means that the temperature of the nozzle is much lower than that of the solder fumes generated. This means in turn that vaporised resins condense and solidify in the nozzle and/or the suction channel such that the suction effect is totally lost as a result of these resin deposits after only some few hours of use. These deposits, or resin plugs, are removed, for example, with the aid of chemical solvents or by mechanical means, which is often a time-laborious task.

A prime object of the invention is to provide a soldering iron in which the deposit of resins in the suction nozzle of the iron is completely or at least substantially avoided, and to the unavoidable deposition of such tough resins is shifted to the readily accessible hose-end connected to the nozzle.

This object is realized by heating the nozzle via a heat transfer coupling to the hot outer casing of the electrically heated element, and attendantly cooling the hose portion within the handle to promote the precipitation of the fume vapors thereon.

FIG. 1 is a side view of an embodiment of the soldering iron according to the invention;

FIG. 2 is a sectional view taken on the line II--II in FIG. 1; and

FIG. 3 is a sectional view taken on the line III--III in FIG. 1.

The illustrated soldering iron has a handle 1 made of plastics, wood or some other suitable material, and a heating element 2 which extends from one end of the handle 1 and which has a metal outer casing, suitably made of steel. The heating element 2 has an internal resistance member to which voltage is applied via a cable 3 passing through a bore 4 in the longitudinal direction of the handle 1. Mounted on the outer end of the element 2 is an exchangeable soldering tip or bit 5 with which solder and flux are melted to effect a soldering operation. Extending along the element 2 is a tubular metal suction nozzle 6 with the outer end 7 thereof directed towards the soldering site. The rear end 8 of the nozzle 6 is connected to a suction channel 9 passing through the handle, this suction channel in turn being connected to a suction hose 10 which is connected to a suction source 11, such as an exhaust fan. When the suction source 11, is operating fumes generated during a soldering operation are withdrawn from the soldering site by suction and depart from the fan 11 through a filter means not shown.

In order to prevent the hot soldering fumes withdrawn from the soldering site from cooling in the suction nozzle 6 to such an extent that resin precipitates on the inner walls thereof, the metallic suction nozzle 6 is in direct metallic connection with the metallic casing of the element 2, and thus in heat transfer connection therewith, in accordance with the present invention. In the illustrated embodiment, this heat transfer connection comprises a metal ring 12 which is placed on the metal casing of the element 2 and which is welded or soldered to the suction nozzle via a metal bridge 13 formed on the ring 12. This enables the nozzle 6 to be readily heated by heat drawn from the heating element. As will be understood, the metal ring 12 may be supplemented with one or more metal rings attached to the nozzle 6, or the ring may be given an axial length corresponding, for example, to the total length of the metal casing, in which case the bridge 13 comprises an elongated flange between the long ring or sleeve and the nozzle.

In order to obtain a concentrated, readily accessible resin deposit, the suction channel 9 comprises the suction hose 10 which is inserted into a bore 15 in the handle to a location therein approximately adjacent the end of the handle, whereat the end 8 of the nozzle 6 is inserted into the end of the suction hose through an opening located in an end plate 14. In the illustrated embodiment the suction hose 10 is considered to comprise a continuous length of hose extending to the suction source 11. It will be understood, however, that the hose may also comprise a plurality of hose sections joined together by means of connectors. At least that part of the suction hose location within the handle preferably comprises a silicone polymer. When the hot soldering fumes have passed through the heated suction nozzle 6 and flow into the plastics suction base 10 the fumes are cooled rapidly to a temperature at which the resin present in the fumes precipitates onto the inner surfaces of the hose. This precipitate can be readily removed, by withdrawing the hose 10 from the bore 15 in the handle 1 and lightly rubbing the end of the hose, thereby to loosen the deposits so that they fall from the hose. In order to provide for a more rapid cooling of the hot soldering fumes, longitudinally extending fins 16,17,18,19 or like spacers may be arranged in the bore 15, as illustrated in FIGS. 2 and 3, these spacers forming between the inner wall 20 of the bore and the outer wall 21 of the hose 10 at least one air through-flow channel, for example the channel 22, which communicates with ambient air. The handle 1 may be provided with a hollow housing 23 closed by means of the cover plate 14 and into which the channel or channels 22 discharge. In this respect air can be drawn in either by venting the cover plate 14 to render it pervious or, for example, by providing a vent, hole 24 in the wall of the housing 23. The channel or channels 22 also opens out, or open out, in a sleeve 25, FIG. 1, and can there be connected to a suction source, which suitably comprises the suction source 11. In addition to the aforesaid rapid cooling of the soldering fumes, and therewith precipitation of resin in the aforementioned hose end, which due to its flexibility and the choice of material for its manufacture is readily cleansed, the additional advantage is afforded that the handle 1 is always maintained at a comfortable temperature.

If for some reason or other a layer of resin should be deposited in the nozzle, this layer can be rapidly removed by interrupting the suction of air into the nozzle. As a result of the aforesaid heat transfer connection the nozzle will be quickly heated to a high temperature, causing the resin to melt and run from the nozzle.

The illustrated and described embodiment of the invention can also be modified in ways other than those inferred above. For example, the ring or sleeve 12 may comprise a metal clamp means connected with the nozzle 6 and clamped firmly on the heating element 2. The illustrated slightly conical shape of the handle 1 can be replaced with any suitable ergonometrical configuration.