Patent GB-657777-A (GB)
Title: Telescopic standard or arm
IPC: F21V21/22
Filed: 1948-07-23
Abstract: 657,777. Taking up slack. MAACK, F. H. July 23, 1948, Nos. 19721, 19722 and 19723. Convention dates, Oct. 3, 1945, May 14, 1946, and June 1, 1946. [Class 78 (ii)] [Also in Groups XI and XIV] A telescopic support for an electric device such as a lamp comprises a helically coiled cable enclosing the electric conductors and extending through an opening in a cylindrical receptacle to be fastened to the peripheral wall thereof, the cable having such flexibility that when the part outside the receptacle is pushed axially through the opening it coils automatically into a flat helical coil within the receptacle. A tightly wound spiral spring 4 (Fig. 2) clamped to the peripheral wall of a cylindrical receptacle 1 extends upwardly through a socket 2 in the top wall of the receptacle and supports at its upper end a lamp holder 5, the electric leads to which pass axially through the spiral spring. On pushing the lamp holder downwardly the spiral spring coils itself within the receptacle in a flat coil of progressively reducing turns; the friction engagement between the spring and the socket 2 holds the lamp holder at any desired extended position. Fig. 4 shows a wall lamp comprising three curved telescopic tubes projecting from a cylindrical receptacle 7. A flexible electrical conductor or a helical spring cable enclosing a conductor which is either loosely coiled and conforms to the windings of the cable or is a tight fit in the cable, extends through the telescopic tubes and coils itself within the receptacle when the tubes are telescoped. In the construction shown in Fig. 5, the electric conductor 18 is tightly coiled in the innermost tube of a telescopic standard and is secured to a slidable member 19 urged upwardly by a spring 22 so as to hold in taut condition the portion of the electric conductor passing through the spring 22 and through the spring cable 23 which coils itself within a base receptacle when the standard is retracted. The receptacle in which the coiled cable coils automatically may be made partly or wholly of transparent material and its base may be cone shaped and provided with spiral grooves and it may be detachable. Radial slots may be provided in the base and axial or peripheral slots in the side wall. In order to provide frictional engagement between the telescopic tubes, wire springs 32, 33 (Fig. 6) formed by winding piano wire on an oval or cornered stick are disposed between adjacent tubes, flanges on the tubes keeping the springs in position. Other means for providing such frictional grip comprise corrugated spring strips wound in collar manner or spirally on the inner tubes, or leaf springs secured to the inner tubes and preferably arranged axially, or metal strips either with pointed tongues or embossed wound around the inner tubes. The frictional contact of the coiled cable with the tubes may serve to maintain the standard in any extended position. A releasable friction device may be provided and upon release the cable may emerge automatically. The Specification as open to inspection under Sect. 91 comprises also a construction in which a curved tube guides the electric conductors through the base of a telescopic standard, the curved tube extending from the lower end of the outer telescopic tube to an outlet in the side of the base; and also comprises a cylindrical cable receptacle with screw wound grooves in its vertical wall and another of conical shape. In each of these receptacles the cable windings lie on top of each other. This subject-matter does not appear in the Specification as accepted.