US1713194A - Vernier drive - Google Patents

Description

May 14, 1929. E R055 1,713,194

VERNI ER DRIVE Fild Deo. 27, 1924 I' "lll/1111111 www i Z7 Inventor: T- Ernest Ross,

2f by M His Attorney.

Patented May 14, 1929.

UNITED STATES l 1,713,194 PATENT' oFElcE.

EENEsr Eoss, or NEWARK, NEW JERSEY, AssIaNoE 'ro GENERAL ELECTRIC con- PANL A coEroEATIoN or NEW Yoan.

VEBNIER DRIVE.

Application led December 27, 1924. Serial No. 758,475.

My present invention relates to a driving apparatus whereby a movement of a driving member produces a relatively smaller movement of a driven member, and more particu- `:s larly to so-called Vernier drive apparatus such as is frequently employed for accurate tuning of electric circuits.

The object of my invention is to provide an apparatus of the class described which will be simple in its construction and positive in its action for driving a rotating member in either directionand which at the same time will permit of any desired reduction in speed between the driving membe` and the member to be driven.

The novel features which I believe to be characteristic of my invention are set forth/ with particular-ity in the appended claim. My invention, itself, however bot-h as to its organization and method of operation will best be understood by reference to the following description taken' in connection with the accompanying drawing inwhich Fig. 1 is a sectional view of an apparatus embodying my invention; Fig. 2 is an end view of the driving portion thereof; Fig. 3 is a diagrammatic representation of a portion of the driving mechanism to illustrate the principle of the operation thereof; Fig. 4 yis a sectional View of a modified form of my invention and Fig. 5 is a diagrammatic representation of the driving mechanism of the form of my invention shown in Fig. 4.

I have indicated in Fig. 1 the application of my invention to a variable condenser of the general type commonly used in radio communication or for similar purposes. This comprises a series of stationary nlates 1 which are secured in a frame work comprising end members 2 and 3 by means of a screw-bolt 4.

The rotating plates 5 of the condenser are mounted upon a hollow shaft 6 being suitably spaced by means of spacing blocks 7 and secured by means of a nut 8. Extending through the hollow shaft 6 is a driving shaft 9 having at its end the usual operating knob 10. The rotating member of the condenser is associated with driving shaft 9 through the medium of a plurality of balls 11. I have indicated in the drawing three of these balls though, of course, a greater number may be employed if desired. Balls 11 are retained between two concentric races, the outer race 12 is secured to a member `13 which in turn is secured by means of nut 14 to the driving shaft 9. The inner race Which'is in the form of a groove is made up of two part-s. The part 15 is secured to the end piece 3 of the condenser by means of a nut 16. The second part 17, of the inner race is adjustable in .order that the balls may be in good contact with both races at all times. The spring 18 which is located between the part ,17 and the end piece 3 of the condenser provides for the desired adjustment of the part 17.'

A retainer 19 in the form of a cylindrical member, having slots 20` cut thereln for receiving the balls 11, is secured to the end of the hollow shaft 6.

yWhen the shaft 9 is rotated the outer race 12 is rotated therewith and this causes the balls l11 to rotate. At the same time the balls move circumferentially in the groove which constitutes the inner race. It will be noted that the two sides of the inner race are inclined toward one' another at an angle, indicated in Fig'.` 3 as a soy that the balls make contact with the two sides of the groove at points 21 which are connected less than 180 apart along the circumference of the balls. As a result each ball rotates with respect to the outer race around a radius equal to the radius of the ball but it rotates with respect to the inner race around a radius equal to the distance indicated on the drawing by the a. As a result when the outer race moves a distance equal to the circumference of the ball, the ball travels cireumferentially along the inner'race a distance only equal'to the circumference of a circle having radius a. By suitable selection of the angle of inclinationa this distance may be made materially less than the distance of travel of the outer race' 12. That is, the smaller angle a isl made, the greater will be the ratiojbetween the distances traveled by the outer race and by the balls along the inner race. As the balls i travel circumferentially in the inner race, they carry with them the retainer 19 and thus impart motion to the driven shaft 6.

In the modification shown in Fig. 4 of the drawing, the same principle is employed in a slightly different way. In this case the knob 10 is attached to a short driving shaft 6', the end .of which carries inner race 22. vA ball retainer 23 which is of similar form to that shown in Fig. 1 is secured to the end of the shaft 24 which carries the movable plates 5 of the condenser. In this case the outer race a good contact with the two races.

25 ismade up in the same way as the inner race of the modification shown in Fig.` 1, a sprinfr 26 serving to adjust the movable portion 2?? of theouter race to keep the balls in The ratio between the distances of travel of the driving member and the member driven in this case, as in the form shown in Fig. 1, depends upon the angle oc A greater ratio in speed reduction however may be obtained with this form because of the fact that the circumference of the race carried by the driving member is much less than in the form shown in Fig. 1. Hence other dimensions being similar, one turn of the knob in the form shown in Fig. 4 will .produce a much smaller movement of lie driven member than in the form shown in im l.

Vhile I have shown and described the preferred embodiments of my invention, it will be apparent that many modifications may be -made in the structure and arrangement of the various parts used as well as in the practical application of my invention without departing from the scope thereof as set forth in lVhat I claim as new and desire to secure by Letters Patent of the United States, is:

A wireless apparatus comprising afrotatable driven sha t, a' panel through which said shaft extends, an indicator member, adjustable means for said shaft, said means comprising an internal friction gear having a knob attached thereto, a stationary friction gear concentric with said internal gear, a

plurality of balls interposed between said

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