US1445812A

US1445812A - Dial kktob

Info

Publication number: US1445812A
Authority: US
Publication date: 1923-02-20
Anticipated expiration: 1940-02-20

Description

Feb. 20, 1923..

c. P.WHITALL' DIAL KNOB Filed July 15, 1922 INVENTOR BY Mm! A ORNE S Patented Feb. 20, i923.

TENT orrics.

v CHARLES P. WHITALL, 0F LONG-MEADOW, MASSACHUSETTS.

DIAL KNOB.

Application filed July 13,

To all 'whomit may concern:

Be it known that I, Crmnnus P. lVHrrALL, citizen of the United States, residing at Longmeadow, in the county of Hampden and State of Massachusetts, have invented new and useful Improvements in Dial Knobs, of which the following is a specification.

The present invention relates to dial knobs such as are used for adjusting various rotatable parts of radio apparatus.

The invention has for its object to provide an improved "molded dial knob of light but rugged "construction and of distinctive and pleasing appearance and one which is particularly well adapted for, economical quantity production.

The invention consists in the novel-and advantageous features of construction hereinafter described with reference to the accompanying drawings and defined in the appended claims. I

In the drawings i Fig. l is a view, in front elevation, of th improved dial knob;

Fig. 2 is a side elevational view thereof;

7 Fig. 3 is a detail sectional view'taken along the line 33 of Fig; 1;

'. line 55 of Fig. 1;

h Fig. 4c is a rear elevational view of the dial Fig. 5 is a sectional view taken alongthe Fig. 6 is a perspective view of the dial knob showing the rear side thereof; and

Fig. 7 is a rear elevational view of a dial knob of larger diameter showing a modified arrangement of stiffening ribs.

The illustrated dial knob comprises an annular dial portion 1 and a centrally disposed knob portion 2, the dial and knob portions being integrally formed of molded dielectric material. As shown clearly in Fig. 5, the dial knob is ofshell-likeconstruction, the walls of the shell beingv made quite thin to save material and to reduce weight. The dial portion is dished or in other words is formed with a flaring margin 3 affording upon its outer sid ean annular'bevelled surface 4- bear- 1 ing a Vernier 5 the graduationsof which are adapted to cooperate with a suitable mark or indicator (not shown) upon a stationary 1922. Serial No. 574,835.

part of the radio apparatus. The hollow knob portion is of frusto-conical shape and its sloping side walls provide abevelled exterior which is knurled as indicated at 7 in Figs. 2 and 6. The small or front end of the hollow knob is closed by an outwardly convex end wall 8 while the large or rear end of the knob is open and the side wall merges, at the open end of the knob, with the inner peripheral portion of the dial.

To receive the spindlev or shaft of the rotatable element to which the dial knob is to be applied, an axially a-pertured hub 9 extends from the inner side of the front face of the knob portion 2. The free. extremity of the hub 9 projects outwardly beyond the plane of the outer rim of the annular dial portion, as shown. in Fig. 4, and serves to space the rim of the dial away from the adjacent face of the cabinet or other casing which encloses the apparatus carrying the dial knob and thus insures ample clearance between the movabledial and the stationary casing.

To strengthen and reinforce the shell-like sidewalls of the dial knob and particularly to stiffen the dished or bevelled portion of the dial, a plurality of radial ribs or webs 10 extend from the hub 9 to points on said side walls .'the stiffening ribs-preferably being equidistant from each other and extending in an axial direction from the end face of the knob portion to the plane of the outer rim of the dial'portion. In the form of dial shown in Figs. 1" to 6, inclusive, three radial stiffening ribs 10 are employed, but more or less could be used as may be found desirable. In a dial knob of greater diameter it may be found advantageous to J provide four strengthening ribs such as indicated at 10 in Fig. 6. I

In addition to stiffening and reinforcing the hollow shell of the dial knob the ribs 10 serve also to prevent distortion or warping of said shell such as would cause the dial to wabble as it rotates. Inasmuch as the dial carries the Vernier it is very desirable that the dial shall have no tendency to wabble as it turns and consequently it will be appreciated that the ribs 10 perform an important function in preventing distortion of the dial. In order that all the dial knobs molded in the same mold shall be free from distortion and shall be precisely uniform in shape, the several radial ribs 10 are, in accordance with an important feature of the present invention, syn'ln'ietrically disposed to avoid any tendency toward distortion of the dial such as might result during the setting or solidifying of themolded material if the radial ribs were non-symmetrically arranged.

To enable the dial knob to be conveniently and fixedly secured to the shaft of the rotatable element to be adjusted, a screw threaded aperture 1.2 extends radially through one of the ribs 10 from the exterior of the knohportion to the interior of the hub, this aperture being adapted to receive a set-screw (not shown) for clamping the dial knob to its shaft.v As shown, clearly at 13 in Fig. 3, the rib 10 through which the set screw is adapted to extend is .as the set-screw is tightened.

thickened to prevent it from being weakened by means of the set-screw receiving aperture. By extending the set-screw aperture through one of the strengthening ribs 10, a greater area of threaded surface is provided for engagement with the threads of the set-screw and consequently there is less liability that the threads in the dial knob will be stripped The importance of this feature will also be appreciated .when it is considered that the dielectric material such as is commonly employedofor making molded dial knobs is usually I more or less brittle and easily chipped... It will also be noted that the setscrew aperture is located adjacent, the base of the knob, i. e., adjacent:the end adjoining the dial thus insuring that the setscrew will engage a shaft which may fail to extend into the knob to the full depth of the aperture in the hub 9. This location employed in heavier and more bulky con structions. 'The mass of material is evenly distributed throughout the present dial knob and this feature, together with the employment of the reinforcing ribs 10 and the symmetrical arrangement of the latter, contributes to the production of a dial knob in which the tendency to warp is practically eliminated. Thus, although the dial knobs may be produced in large quantities, the

finished articles will be uniform in shape and free from distortion.

The invention having been described, what is claimed is i l. A molded dial knob comprising a central knob portion, a thin dished dial portion flaring outwardly from the knob portion, and radial reinforcing ribs on the concave side of the dial portion.

2. A dial knob comprising a central knob portion, a thin dished dial portion flaring outwardly from one end of the knob, a central hub projecting from said end of the knob, and a plurality of strengthening ribs radiating from said hub and merging with the concave side of the dial.

A dial knob comprising a-hollow central. knob open at one end, a dished annular dial having its inner marginal portions merging with the side wall of the knob at the open end of the latter, a hub projecting inwardly from the closed end of the knob and axially apertured for the reception of a shaft to be turned, and a plurality of stiffening ribs radiating in equally spaced apart relation from said hub and merging with said knob and dial along the inner surface of the knob andalong the concave side of thedial from the inner to the outer periphery of the latter.

4:. A dial knob comprising a hollow centralknob open at one end, adished annular dial having its inner marginal portion merging with the side wall of the knob at the open end of the latter, a hub projecting inwardly from the closed end of the knob and axially a-pertured for the reception of a shaft to be turned, and a plurality of stiffening'ribs radiating symmetrically from said hub and merging with said knob and dial along the inner surface of the knob and along the concave side of the dial, theside wall of said knob having a screw-threaded aperture extending radially therethrough in line With one of said ribs, said aperture also extend ing through said rib and communicating with the axial apertured in said hub to receive a setscrew for securing said shaft to the dial knob.

5. A dial knob comprising ahollow central knob open-at one end, a dishediannular dial having its inner marginal portions merging with the side wall of the knob at the open end of the latter, a hub projecting inwardly from the closed end of the knob and axially apertured for the reception of a shaft to be turned, and a plurality of. stiffening ribs radiating from said hub and merging with said knob and dial: along the inner surface of the knob and along the concave side of the dial from the inner to the outer periphery of the latter.

6. A dial knob comprising a hollow. knob portion closed at one end, a thin dished dial portion flaring outwardly from the opposite end of saidknob portion, a hub integral with said closed end of the knob portion, said hub extending axially through the interior of the knob portion and projecting from the dial end of the knob to a point beyond the plane of the-outer periphery of the dial portion, and a plurality of portion and with the concave side of the dial 10 portion.

In testimony whereof I have afiixed my signature.

CHARLES P. WHITALL.