SOLDERING TOOL

Abstract: A soldering tool (1) comprises a handle (2), a lamp mounting portion (3), a heat insulator (8), an aluminium base portion (4), a socket (10) with an electrical feed (7), an infrared lamp (11) having an in-built elliptical reflector, an aluminium collector cap (5) (having a lamp accommodating portion (5a), an elliptical portion (5b), an aperture (5c) and a tubular portion (5d)) mounted over the base (4) by a bayonet fit (12), and an end cap (6) for mounting a cold mirror (13). Light from the lamp (11) reflects between the lamp's reflector and the cap (5) until it exits aperture (5c) to produce an output beam of e.g. 11 mm diameter, the cold mirror passing infrared light but not visible light apart from some red light for aiming purposes. The invention provides an easily used and controllable soldering tool especially useful for single point and small area soldering. The lamp reflector (11) and cap (5) may be trough-shaped to produce a stripe-shaped output.

Description: Soldering Tool The present invention relates to soldering tools, and especially to infra-red soldering apparatus. Soldering apparatus is known which uses an infra-red lamp. For example, GB 2194479 discloses an infra-red rework station. The present invention aims to provide a new infrared soldering tool, which may be particularly useful in single point and small area soldering, and which may be used in place of for example standard hot gas tools or metal contact soldering irons. Viewed from one aspect, the present invention provides a soldering tool comprising an infra-red lamp over the front of which is mounted a collector cap for reflecting light back towards the lamp, the cap having an aperture therein through which the light may pass to produce an infra-red beam. In accordance with the present invention, light from the lamp is reflected back and forth between the reflector of the lamp and the cap until it exits through the aperture to provide a concentrated infra-red beam which may for example be used for single point and small area soldering and to flow solder for any suitable purposes, e.g. for the reworking of components. The tool may be made simply, inexpensively and compactly, and may be provided as a hand-tool. Preferably, the cap has a tube portion extending from the aperture along which light reflects on passing out of the aperture. This helps to provide a more defined beam, and allows the tool to be more easily aimed. The lamp is preferably of the type having an elliptical reflector, which may for example be gold- plated. The lamp may have a major diameter in the range of e.g. between about 50 mm and about 60 mm and a minor diameter in the range of e.g. between about 40 mm and about 50 mm. The lamp may be e.g. an Osram HLX 64635 lamp. Preferably, the focus of the lamp lies within the collector cap, and may be about 19 mm forward of the lamp's plane front face. The collector cap is preferably elliptical in shape, and may be rotationally symmetric, i.e. it may comprise an end portion of an ellipsoid. The ellipse of which the cap is a portion preferably has a major diameter in a range of between about 80 mm and about 100 mm, and a minor diameter in a range of between about 50 mm and about 75 mm. A major diameter of about 92.0 mm and a minor diameter of about 64.3 mm is especially preferred. The collector cap is preferably made of aluminium, and preferably has a highly polished interior surface to reflect the light. The tube portion preferably has a length of between about 5 mm and about 15 mm, and is preferably about 11 mm long. It too preferably has a highly polished internal surface for reflecting the light. The tool preferably includes a filter, e.g. a cold mirror, in order to filter out most of the visible light emitted by the lamp. Preferably, the filter allows some visible light through, e.g. a degree of red light, to allow for the aiming of the tool. For example, the cold mirror may stop about 95% of the visible light produced by the lamp, allowing the other 5% of the visible light (red light) together with the infra-red light to pass through. The cap aperture is preferably, although not necessarily, circular. Different diameters of output beam may be produced by varying the diameter of the collector cap aperture. For example, one tool may have an aperture diameter of about 11 mm, and another may have a diameter of about 7 mm. The size of the ellipse need not be varied with varying aperture size . Instead of using an ellipsoid and e.g. a circular aperture, it would also be possible to form a linear, e.g. stripe-shaped, beam by using a lamp and/or collector cap having trough shapes of preferably elliptical cross- section, with the aperture being in the form of a slit. A tube portion of elongate cross-section may then extend out from the aperture . In one preferred form, the tool comprises a handle portion, e.g. of moulded plastics, at one end of which is mounted a base, e.g. of aluminium, in which is a socket e.g. of a standard ceramics design, for receiving an infra-red lamp therein. Preferably an insulator of e.g. PTFE is mounted between the handle and base to reduce the transfer of heat to the handle. The collector cap may connect with the rest of the tool, e.g. the base portion, in any suitable manner, and so that it is preferably removable, e.g. by a bayonet fitting. The collector cap may comprise a cylindrical portion for accommodating the lamp, an elliptical light reflecting portion and an aperture tube portion. A cold mirror may be mounted on the end of the tube portion through the use of an end cap having an aperture therein, which may be mounted by an interference fit onto the end of the tube portion to hold the mirror in place. A tool made in accordance with the above provides an easily used device of simple and inexpensive design, whose lamp may be easily replaced by turning and removing the cap and by then unplugging the lamp from the socket. The tool uses no optics other than the filter element to produce a concentrated well-defined beam that may be used in single point and small area work. An electric feed to the lamp may pass along the centre of the handle, and may connect the socket to a suitable power supply. This power supply may be controllable, e.g. by dedicated electronics or through a connection with a computer, so that heating times and power levels of the lamp may be varied to provide simple and effective control of the lamp and to allow for the definition of total heat cycles. For example, in order to prevent thermal shock, the power level of the lamp may be initially set to a low level in order to pre-heat a component to be reworked, before increasing the power to reflow the solder. This control of the tool contrasts with the prior art metal contact soldering irons which cannot easily be controlled. A suitable power supply would be one of those provided by PDR Microelectronics Limited. Viewed from a further aspect, the invention provides a soldering tool, in which light from an infra-red source is reflected between a pair of elliptical surfaces before exiting through an aperture in one of the ellipses. Viewed from a still further aspect, the invention provides a soldering tool, in which an infra-red lamp having an elliptical reflector has an elliptical collector cap mounted thereover to collect light emanating from the lamp and to reflect the light back to the lamp reflector, the cap having an aperture therein through which the light exits. The invention may also be viewed as providing a soldering tool comprising a socket for an infra-red lamp and a collector cap mounted over the socket for reflecting in use light from a lamp mounted in the socket back towards the lamp, the cap having an aperture therein through which the light may pass to produce an infra-red beam. Viewed from another aspect, the invention provides a hand-held soldering tool comprising a handle portion, a lamp-mounting portion having a socket therein for receiving in use an infra-red lamp, and a removable collector cap, the cap having a reflecting portion and an exit aperture, the arrangement being such that in use the light from a lamp mounted in the socket reflects between the cap reflecting portion and the lamp and passes through the cap exit aperture to produce an infra-red beam of light. An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings , in which: Fig. 1 is a side view of a soldering tool according to one embodiment of the present invention; Fig. 2 is a cross-sectional side view of the tool of Fig. 1; Fig. 3 is a cross-sectional view of the collector cap of the tool of Fig. 1 ; Fig. 4 is a cross-sectional view of the aperture end cap of the tool of Fig. 1; Fig. 5 is a front view of the end cap of Fig. 4; and Figs. 6 and 7 are front and side views of the cold mirror of Fig. 2. Referring to Fig. 1, a soldering tool 1 comprises an elongate plastics moulded handle 2 having a lamp mounting end 3 of truncated cone shape . A base portion 4 of a complementary shape to the end 3 and made from aluminium is housed within the end 3 for receiving a lamp therein. A collector cap 5 made of aluminium is mounted over the base 4 and lamp, and has an aperture end cap 6, also of aluminium, push-fit thereon in an interference manner. An electrical lead 7 provides power to the tool from a suitable source which may control the power and heating times of the lamp. Referring to Fig. 2 (and also to Figs. 3-7), between the handle 2 and base 4 is an insulator 8 of PTFE for reducing heat transfer to the handle 2. The base 4 is connected to the handle 2 by screws and clamps the insulator 8 in place, and the handle 2 passes the electrical feed 7 along its length via an inner chamber 9 to a ceramic socket 10 of a standard 2-pin design which is screw-mounted within the base 4. An infra-red lamp 11, such as an Osram HLX 64635 lamp, is plugged into the socket 10. The lamp 11 has a gold-plated elliptical reflector of major diameter of about 50 mm and minor diameter of about 40 mm. The filament of the lamp 11 is mounted at one focus of the reflector, so as to focus light from the filament to a second focus about 19 mm forward of the front plane of the lamp 11. The collector cap 5 connects with the base 4 through a bayonet fit 12. The collector cap 5 has a cylindrical first portion 5a for accommodating the lamp 11, an elliptical portion 5b for reflecting light from the lamp 11 back to the lamp 11, and an aperture 5c from which extends a tube portion 5d for allowing a beam of concentrated light to pass out from the tool 1. The elliptical portion 5b is from an ellipse having a major diameter of 92.0 mm and a minor diameter of 64.3 mm. The cylindrical portion 5a is about 27 mm in length and has an internal diameter of about 55 mm. The elliptical portion 5b comprises a portion of the ellipse which extends about 23.8 mm along the ellipse's major axis from one end thereof, and the aperture portion 5d has an inner diameter of about 13.5 mm and a length of about 11 mm. The inner surface of the collector cap 5, at least in the region of the elliptical portion 5b and the aperture tube portion 5d, is highly polished to efficiently reflect the light. At the end of the aperture tube 5d is a cold mirror 13 which passes infra-red light and a degree of red light, but which reflects other wavelengths. The passing of the red light allows for the tool's beam to be accurately aimed. The cold mirror 13 is held clamped to the end of the aperture portion 5d by the interference- fit end cap 6, which has an aperture 6a therein of the same diameter as the aperture 5c, and flange portion 6b for engaging the cold mirror 13. The tube portion 5d has a shoulder portion 5e thereabout onto which the end cap 6 is fitted. The tool 1 provides an infra-red beam of about 11 mm. Beams of different diameters may be provided by altering the diameter of the aperture portion 5d, e.g. a 7 mm beam may be provided by using a 7 mm aperture diameter. The tool is especially useful for single point and small area soldering, and provides a simple, easily used and controllable hand-tool. The above embodiment is described by way of example only, and variations and modifications on the above are possible. For example, the lamp and/or collector cap could be trough-shaped with e.g. elliptical cross- sections to produce a beam of rectangular shape.

Claims: Claims 1. A soldering tool comprising an infra-red lamp over the front of which is mounted a collector cap for reflecting light back towards the lamp, the cap having an aperture therein through which the light may pass to produce an infra-red beam. 2. The tool of claim 1, wherein the lamp includes an elliptical reflector. 3. The tool of claim 2, wherein the lamp reflector has a major diameter in the range of between about 50 mm and about 60 mm. 4. The tool of claim 2 or 3 , wherein the lamp reflector has a minor diameter in the range of between about 40 mm and about 50 mm. 5. The tool of any preceding claim, wherein the focus of the lamp lies within the collector cap. 6. The tool of any preceding claim, wherein the focus of the lamp is about 19 mm forward of the lamp's front face . 7. The tool of any preceding claim, wherein the collector cap has a light reflecting portion which is elliptical in shape. 8. The tool of claim 7, wherein the cap reflecting portion is a portion of an ellipse having a major diameter in a range of between about 80 mm and about 100 mm. 9. The tool of claim 7 or 8 , wherein the cap reflecting portion is a portion of an ellipse having a minor diameter in a range of between about 50 mm and about 75 mm. 10. The tool of claim 7, 8, or 9 , wherein the cap reflecting portion is a portion of an ellipse having a major diameter of about 92.0 mm. 11. The tool of claim 7, 8, 9 or 10, wherein the cap reflecting portion is a portion of an ellipse having a minor diameter of about 64.3 mm. 12. The tool of any preceding claim, wherein the collector cap is rotationally symmetric. 13. The tool of any preceding claim, wherein the collector cap comprises an end portion of an ellipsoid. 14. The tool of any preceding claim, wherein the collector cap comprises a cylindrical portion for accommodating the lamp, an elliptical light reflecting portion and an aperture tube portion. 15. The tool of any of claims 1 to 11, wherein the collector cap has a trough-shaped light reflecting portion of elliptical cross-section, with the cap aperture being in the form of a slit. 16. The tool of any preceding claim, wherein the collector cap is removable. 17. The tool of any preceding claim, wherein the collector cap is made of aluminium. 18. The tool of any preceding claim, wherein the collector cap has a highly polished interior surface to reflect the light. 19. The tool of any preceding claim, wherein the cap has a tube portion extending from the aperture along which light reflects on passing out of the aperture. 20. The tool of claim 19, wherein the tube portion has a length of between about 5 mm and about 15 mm. 21. The tool of claim 19, wherein the tube portion is about 11 mm long. 22. The tool of claim 19, 20 or 21, wherein the tube portion has a highly polished internal surface for reflecting the light. 23. The tool of any preceding claim, wherein the tool includes a filter in order to filter out visible light emitted by the lamp. 24. The tool of claim 23, wherein the filter allows some visible light through to allow for the aiming of the tool. 25. The tool of claim 23 or 24, wherein the filter allows red light to pass through. 26. The tool of claim 23, 24 or 25, wherein the filter is mounted over the cap aperture by an end cap having an aperture therein across which the filter extends . 27. The tool of any of claims 23 to 26, wherein the filter is a cold mirror. 28. The tool of claim 27, wherein the cold mirror stops about 95% of the visible light produced by the lamp, and allows the other 5% of the visible light together with the infra-red light to pass through. 29. The tool of any preceding claim, wherein the diameter of the collector cap aperture is about 11 mm. 30. The tool of any of claims 1 to 28, wherein the diameter of the collector cap aperture is about 7 mm. 31. The tool of any preceding claim, wherein the tool is a hand-held tool. 32. The tool of any preceding claim, wherein the tool comprises a handle portion at one end of which is mounted a base in which is a socket for receiving an infra-red lamp therein. 33. The tool of claim 32, wherein an insulator is mounted between the handle and base to reduce the transfer of heat to the handle. 34. The tool of claim 32 or 33, wherein an electric feed to the lamp passes along the centre of the handle. 35. The tool of any preceding claim, wherein the lamp is powered by a power supply which is controllable to vary the heating times and power levels of the lamp. 36. The tool of claim 35, wherein the power supply allows the power level of the lamp to be initially set to a low level in order to pre-heat a component to be reworked, before being increased to reflow solder of the component . 37. A soldering tool, in which light from an infrared source is reflected between a pair of elliptical surfaces before exiting through an aperture in one of the ellipses . 38. A soldering tool, in which an infra-red lamp having an elliptical reflector has an elliptical collector cap mounted thereover to collect light emanating from the lamp and to reflect the light back to the lamp reflector, the cap having an aperture therein through which the light exits. 39. A soldering tool comprising a socket for an infra-red lamp and a collector cap mounted over the socket for reflecting in use light from a lamp mounted in the socket back towards the lamp, the cap having an aperture therein through which the light may pass to produce an infra-red beam. 40. A hand-held soldering tool comprising a handle portion, a lamp-mounting portion having a socket therein for receiving in use an infra-red lamp, and a removable collector cap, the cap having a reflecting portion and an exit aperture, the arrangement being such that in use the light from a lamp mounted in the socket reflects between the cap reflecting portion and the lamp and passes through the cap exit aperture to produce an infra-red beam of light.

Inventors: GIBBS ROGER HANS, GIBBS, ROGER, HANS
Applicants: GIBBS ROGER HANS, PDR MICROELECTRONICS LIMITED, GIBBS, ROGER, HANS
Application year: 1997
Main classification: B23K1
IPC codes: B23K1