Patent GB-209452-A (GB)
Title: Improvements in or relating to adjusting or regulating means or apparatus more particularly for use in connection with instrument work
IPC: G01B3/18
Filed: 1922-09-06
Abstract: 209,452. Rogers, W., and Wingrove, C. W. Sept. 6, 1922. Wireless tuning apparatus and resistances, adjusting and indicating devices for.-The coarse and fine adjustments of tuning coils, condensers, rheostats, &c., are effected by rotation of a single handle or knob. Fig. 1 shows one construction in which a coil-holder 1 is adjusted by a knob 6 and then given a fine adjustment in the reverse direction by reverse rotation of the same knob. The operating-spindle 5 passes through side plates 2, 3, in the latter of which is a circular recess 4. Brazed or otherwise secured to the spindle 5 is a crank plate 7, shown in Fig. 3, carrying a pin 8 and formed with shoulders 9. Loose on the spindle 5 is a plate 12, shown in Fig. 4, which has a slot 16 through which the spindle passes and a slot 15 in which the pin 8 engages. An eccentric 13<3> is attached to the plate 12, and is formed with aligned pins 13<1>, 13<2>, the latter of which engages a slot 14 in the coil-holder 1. The eccentric 13<3> fits into a hole 11 in a plate 10, which is clamped friction tight against the side plate 3. On turning the knob 6 the crank plate 7 is rotated until one of the shoulders 9 engages the pin 13<1> and thereby rotates the block 1 positively, the pin 8 and plate 12 being in one of the positions shown in Fig. 5. On reverse motion of the knob 6, the pin 8 moves the plate 12 about the centre of the eccentric 13<3>, thereby causing the pin 13<2> to describe the arc of a small circle having a radius equal to the distance between its centre and that of the eccentric, the plate 10 being held stationary by friction. In a modification a hole is made in the plate 10 with which the pin 8 may be engaged at the centre of its travel by axial motion of the spindle 5, thereby causing the spindle and block 1 to move at the same speed. On pushing in the spindle, the pin 8 is disengaged from the plate 10 and a fine adjustment may be made in either direction. Another construction is shown in Figs. 7 and 8, Fig. 8 being a plan on the line A, A, Fig. 7. A knob 33, loosely surrounding the spindle 18, carries a pin 34 which passes through a clearance slot 30 in a frictionallyheld plate 28 and engages a slot 26 in a plate 24, which also has a slot 25 and a slot 27 clearing the spindle 18. 'With the slot 25 engage a pin 31 fixed to the plate 28 and a pin 23 attached to a bifurcated plate 22 which is fastened to a sleeve 21 surrounding the spindle 18 and fixed thereon by an insulating slotted bush 35 which is forced along a tapered part of the bore of the sleeve 21 by a screw 36, which also compresses a spring 38 bearing against a shoulder 37 on the knob 33, so as to cause the plate 28 to bear with friction against the plate 19, which may have a graduated edge. On rotation of the knob 33, the pin 34 moves to one end of the slot 30 in the plate 28 and the whole mechanism moves solidly, giving the coarse adjustment. On reverse rotation, the pin 34 moves the plate 24 about the pin 31 as centre, thereby causing the pin 23 to describe a small arc about the same centre, giving a fine adjustment to the shaft 18. A spring 40 makes contact with the sleeve 21, and may be utilized for earthing the dial and knob of the instrument, so as to provide a capacity screen.