US1602496A - Vernier for radiodials - Google Patents

Description

E. B. LEWIS VERNIER FOR RADIODIALS Filed May 12. 1924 awuwnto'c Earle B. Lewis. w fiwaum Patented Oct. 12, 1926.

UNITED STATES EARLE B. LEWIS, or WATERBURY, coNNEcrIcun VERNIER FOR RADIODIALS.

Application filed May 12,

This invention relates to radio apparatus, and more particularly to a vernier attachment for tuning dials adapted to produce a fine adjustment of condensers, variometers, and other tuning instruments.

One object of this invention is to provide a vernier attachment of the above nature, which is adapted to be located between the tuning dial and the panel of a radio set.

A further object is to provide a vernier attachment in which all of the working parts except the operating knob, are entirely concealed by the dial.

A further object is to provide a device inexpensive to manufacture, easy to manipulate, compact in size, and very efficient and durable in use.

lVith these and other objects in view, there has been illustrated on the accompanying drawings one form in which the invention may be conveniently embodied in practice.

Fig. 1 represents a front elevation of a radio panel and tuning dial, upon which the vernier attachment has been installed. 7

Fig. 2 is a side sectional view of the same. Fig. 3 is a view of the vernier lever and operating knob, shown apart from the remainder of the device.

Fig. 4 is a separate view of the friction late. p Fig. 5 is a separate view of the vernier lever and friction plate shown in their relative positions.

Referring now to the drawings in which like reference numerals denote corresponding parts throughout the several views, the numeral 10 indicates the panel of a radio set, said panel being apertured at 11 to receive av shaft 12 of a tuning instrument, not shown, such as a condenser, variometer, or the like.

In order to permit the tuning instrument to be roughly adjusted, a tuning dial 13 is mounted on the outer end of the shaft 12 in front of, and spaced from, the panel 10. The dial 13'has a central recess 14 extending into its rear face, said recess being fitted over the shaft 12. The dial 13 is detachably secured in position upon the shaft 12 by a screw 15, which is threaded in a countersunk passage 16 in the lower part of a knob 17. The knob 17 is preferably knurled in order to permit the dial to be readily manipulated for roughly tuning the instrument. The dial 1924- Serial No. 712,841.

13 is provided with a thin beveled rim having a suitably graduated scale 18 extending for a half-circumference. A reference mark 19 is located on the panel above the dial.

In order to permit a finer or more accurate adjustment of the dial, after the rough adjustment'just referred to has been performed, provision is made of a vernier attachment comprising a vernier lever 20 and a friction plate 21, referably constructed from flat sheet metal The vernier lever 20 is provided'with straight end portions 22 and 23 and an intermediate enlarged sec- S tion 24:. The enlarged section 24 is substanof the above nature which will be simple,

tially oval-shaped, and'has an arcuate cutout section25, the sides of which are equal- 1 1y spaced from the shaft 12,-previously mentioned. The vernier lever 20 is provided at its upper end with a rearwardly projecting pin 26, said pin beingpivotally seated in a recess 27 formed in the panel 10. The lower end of the vernier lever 20 is provided with a small operating knob 28 extending away from the direction of the panel, and

suitable manner.

A' pointer 29' is provided on the extremity of the vernier lever below the knob 28, and said pointer is adapted to rotate in front of a circular scale 30 located on the panel be low the dial 13,.as clearly shown in Fig.1. In order toprevent the vernier lever from scratching the panel, the lower end of said lever is offset forwardly, as most clearly shown in Fig. 2, and provided with apad 29 of'felt or other soft material.

The central position of the vernier lever is clearly shown in full lines in Figs. 1 and 5, while the extreme positions of said lever are shown by the dotted lines '31 and 32 of Fig.

said knob being secured in positionin any 5. The upper extremity of the vernier lever is providedwith a small forwardly project ing lug 33, said lug being adapted to slidably fit within a slot 34 formed on the upper end of the friction plate 21, previously mentioned. The lower end of the friction plate is provided with a slot 35 similar in all respects to the slot 34.

The side arms of the slots 34 and 35 are provided with circular recesses 36 and 37 respectively, the recesses 37 being of somewhat larger diameterthan the recesses 36.

ameter, the friction plate 21, of course, being reversed from the position shown in Fig. 5, when used on said smaller shaft. In either case, the diameter of the circular recesses is made slightly smaller than the diameter of the shaft upon which the friction plate is to be mounted, so that the side members of the slots will resiliently grip the shaft. I

The central position of the friction plate 21 is shown in full lines in Fig. 5, the estren'ie positions of said plate being shown by the dotted lines 38 and 39. It will thus be seen that when the lever is operated, the angular rotation of the friction plate 21, and consequently that of the tuning dial 13 which is frictionally connected therewith, will be very small compared with the angular rotation of the Vernier lever 20. In other words, a relatively large movement of the Vernier lever 20 will result in a relative] y small movement of the tuning dial 13.

It will be noted that since the vernier lever 29 and the friction plate 21 are pivoted upon different fulcrums, the smaller the distance between the pin 26 and the lug 33, the greater will be tl mechanical advantage and sensitiveness of the vernier attachment. The vernier attachment should, however, be preferably so designed to give a mechanica advantage of ten, so that movement of the vcrnier lever 20 from one extreme position to the other (about points of the scale 30) will cause the tuning dial 13 to rotate only about five points on the scale 18.

In operation, when the Vernier lever 20 is rotated to the right, the lug 33 will move to the left, and by reason of its sliding engagement in the slot 3% of the friction plate 31, will cause said plate to move in the same angular direction. The shaft 12, which is resiliently clamped by the friction plate 31 will also rotate in the same direction, carrying the dial 13 with it. The friction plate 21 is preferably so designed that while the friction on the shaft is sullicient to cause the tuning dial to rotate in response to a movement of the vernier lever, said friction will be insuiiicientto cause the V6I'I1l6IlSVGI' to move when the dial is being manipulated specification one form in which the invention may be embodied, it is to be understood that this form is shown for the purpose of illustration only, and that the invention 15 not to be limited to the specific disclosure but may be modified and embodied in various other forms without departing from its spirit. in short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, and for which it is desired to secure Letters Patent, is:

1. In a radio tuning device, a shaft adapted to extend through a panel, a dial on said shaft, a slotted plate havin its side arms clamping frictionally on said shaft, a lever having a lug slidably fitted in said plate, said lever having a fulcrum supported by said panel, the rotation of said lever causing said plate and'dial to turn in the same direction, but through a much smaller angular amount, both ends of said plate having slots, said slots having enlarged recesses of different diameters, to permit said plate to be interchangeably and resiliently clamped on sha ts of different diameters.

2. In a radio tuning device, a shaft, a plate on said shaft, said plate having slotted ends communicating with enlarged recesses of different sizes, an operating lever, said lever carrying a pin for engaging said plate, the slotted ends of said plate being adapted to frictionally engage said. shaft whereby the rotation of said lever will cause said shaft to rotate, the opposite ends of said plate being adapted to be interchangeably clamped on shafts of different diameters.

3. In a radio tuning device, a shaft, a plate having a plurality of frictionally gripping slotted sections for clamping upon shafts of different diameters, an operating lever, means on said lever for engaging said plate in a slotted section other than that which frictionally grips said shaft at a point eccentric to the fulcrum of said lever whereby the rotation of said lever will cause said shaft to rotate through a different angular amount.

In testimony whereof, I have affixed my signature to this specification.

EARLE B. LE'WI

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