Patent GB-622275-A (GB)
Title: Improvements in and relating to wireless receiving apparatus
IPC: H04B1/08
Filed: 1944-11-10
Abstract: 622,275. Wireless receiving sets. RABINOWICZ, M. Nov. 10, 1944, Nos. 22186/44, 5487/45 and 6884/45. [Class 40 (v)] [Also in Group XL (b)] A wireless receiver is tuned by rotating the casing about a column, the components, including the tuning means, being mounted on a platform fixed to the column and spaced from the casing, and the loud-speaker being mounted inside the casing. In one embodiment, Fig. 1, the casing 5 is guided by a spindle 25 having a fixed collar 26 against which is clamped a flanged supporting plate 27. The spindle is clamped to the base support by a spacing sleeve 30 and a nut. A bearing sleeve 31, which rests upon a ball bearing supported by collar 26, carries at its upper end a gear-wheel 35 and a hub 33 rigidly connected to casing 5 by arms 321. The variable condenser 10 is mounted on the plate 27 and is driven by gearwheels 35, 34. The casing 5, which is locked to the base support by flanged rings 36, 37, is pierced by windows 38 covered with translucent material of a different colour for each station, illuminated in turn by dial lamp 39. A screen 40 prevents more than one window being illuminated at the same time. The volume control 41 is mounted on the inside of the base support, the knob being reached through a cut-out portion. The loud-speaker 17 is mounted on the inside of the casing at the top. In another arrangement, Fig. 2, the hub 58 of a spider, fixed to casing 5, is carried on a spindle 59 rotatable in a bearing column 60, which is clamped to the top wall 61 of the base support 62. The weight of the casing is carried by a bearing collar 67 fixed on the upper end of column 60. The condenser 10, mounted beneath wall 61, has a, spindle 11 ca,rrying discs 71 which co-operate with disc 70, carried by spindle 59, to form a friction drive. Hub 72 is fixed to spindle 11 and carries a translucent dial strip 73, illuminated by a dial lamp (not shown) and viewed through window 74. Other controls are mounted below wall 61 on a recessed panel 76, opposite to window 74. A fixed casing part 77 may be provided on the lower part of the base support 62. In a modification (Fig. 3, not shown), the spindle carrying the upper casing part is rotatable inside a tubular bearing column forming part of a stand. The tuning condenser, which is mounted on the upper side of a plate clamped to the bearing column, is driven by two pulleys and a flexible belt. Subsidiary controls are mounted on the underside of a lower casing part clamped to the bearing column. The rotatable upper casing carries a dial lamp and pointer, acting as a stop to limit the movement of the casing, which co-operate with a dial strip on the lower casing. In another arrangement, Fig. 4, a spherical casing is carried by a pillar 101, forming part of a floor stand. The hub 108 of a plate 107, covering an opening in the lower casing part 106, is freely rotatable about the pillar 101, to which is clamped a platform 100. A variable condenser 10, driven by gear-wheels 111, 110, is mounted on the platform 100. The upper casing part is carried by a spider, whose spindle 109 carries the gear-wheel 110. The floor stand is made adjustable in height and carries the subsidiary controls, as described in Specification 622,360. In a modification (Fig. 6, not shown), the casing is supported by the hub of the cover-plate. The floor stand is insulated from the supporting plate, and the stem carries a sleeve keyed to the hub and rotating with it. This collar carries part of a cord and pulley drive for the tuning condenser, which is supported in an opening in the plate with its spindle projecting downwardly. The subsidiary control members, mounted on the pillar, are operated as described in Specification 622,360. A combined broadcast and television receiver, Fig. 5, has a casing comprising two parts 51, 52 independently rotatable with respect to the base support cabinet 140 which houses the cathode-ray tube 141, and the power supply for the receiver. Casing parts 51, 52 are rotatable about spindle 251 which is fixed to the top wall 143 of cabinet 140. A supporting disc 27 is clamped to spindle 251 and carries condenser 10 on its upper surface and condenser 210 on its underside. Condenser 10 is the tuning condenser for the normal broadcast bands and is operated by turning casing part 51 as in Fig. 2. Casing part 52 is carried by two arms 147 integral with a hub 148 on a sleeve 145, rotatable about spindle 251. Sleeve 145 carries a gear-wheel 135 which operates the tuning condenser 210 for television reception through gear-wheel 134. The upper end of casing 52 is guided between the open end of casing 51 and a flange 27a on plate 27. The gear ratio of wheels 134, 135 is chosen so that a clear space below plate 27 is not swept through by arms 147. Connecting leads to the upper part of the receiver from the pedestal, and the spindles of subsidiary manual controls pass through this space, the main part of the controls being mounted on brackets below plate 27. Access to the knobs, which extend through wall 143, is provided by an opening in the side of cabinet 140. By suitable gearing an entire frequency band may be covered by a partial rotation of the casing or casing part, and wavechange switching may be effected automatically by a switch such as that shown in Fig. 7. A switch arm 150 mounted on plate 27 has two insulating arms 152, 153. When the casing 5 is turned beyond the position shown, projection 151 engages arm 152 so that switch arm 150 makes with contact 154, connecting coil a across coil b. A second switch arm 155 is mounted so that when casing 5 is turned through a further angle a third inductance c is connected in parallel with inductances a and b to cover the highest frequency range. Arms 153, 157 serve to return the switch arms 150, 155 to their normal positions when casing 5 is returned to the position shown. Another switching arrangement (Fig. 8, not shown) comprises one or more pairs of spring contacts for each pretuned circuit or group of circuits. The contacts are mounted on plate 27 and are pressed together by a projection on the inside of the rotatable casing.