GB761760A - Improvements relating to high frequency induction heating - Google Patents

Abstract

761,760. Induction heating. RADIO HEATERS, Ltd. July 6, 1954 [April 8, 1953; April 23, 1953], Nos. 9557/53 and 11245/53. Class 39(3) A heat concentrator for heating gear teeth. comprises a sheet metal cylinder 1 with an end plate 3 and a trough shaped part 4 having an aperture 9 in which is arranged the end of a ferro-magnetic core 7. The cylinder and trough shaped part are slotted at. 2 and 12 so that the currents induced in the cylinder by a coil 11 flow about the end of the core and intensify the heating at that part. The core may be of circular or square cross-section. The trough shaped part is slid along the gap between adjacent gear teeth and in order to obtain uniform heating the part 4 is moved more rapidly at the ends of the gap. Alternatively the part 4 is withdrawn slightly from the bottom of the gap as it traverses the ends thereof. Cooling water is delivered to the cylinder and flows out from the slots. In Fig. 4 the heating part 14 has a core 16 and is supplied with cooling water via pipes 18, 19 and 20. For spot welding the cylinder is closed at its lower end by a shallow conical slotted disc, and a cylindrical core is positioned with its end in an aperture at the apex of the cone. Such an arrangement, together with a high frequency coil, may be mounted in a, hand tool in the form of a pistol provided with a trigger operated switch. A concentrator for soldering the joints between pipes 38, 39, Fig. 8, includes a concave slotted plate 35 at the end of a slotted cylinder, with the end of a rectangular core 36 in an aperture in the plate. For heating a lathe bed &c. a flat slotted disc is attached to the end of a slotted cylinder, and a rectangular core extends axially of the cylinder and has one end in an aperture in the disc. In Fig. 10 a rotating crankshaft journal 47 is heated by a concentrator comprising a concave slotted disc 48 at the end of a slotted cylinder 1 with a rectangular core 49. A similar arrangement with a slotted convex disc and a core at the end of a slotted cylinder for heating cylindrical bores is described. Reference has been directed by the Comptroller to Specification 635,421.