US2417814A - Phonograph needle guard - Google Patents

Description

I. L (m y I IIIIIIH|||||||||m PHONOGRAPH NEEDLE GUARD Fi'led Feb. 16, 1945 atented ar. 25, 1947 FFICE PHONOGRAPH NEEDLE GUARD Colin B. Dale, Oak Park, 111., assignor to Webster- Chicago Corporation, Chicago, 311., a corpora tion of Illinois Application February 16, 1945,Serial No. 578,224

For many years it has been known that cons derable damage results from careless handlin of the phonograph p ck-up or tone arm which carries the needle. This has become especially serious in recent years due to the use of the so called permanent needles. Not only are these needles relatively expensive. but quite often they are permanently afiixed within the pick-up cartridge, so the damage to the needle necessitates a repairmans attention. Even a needle designed for a single playing is likely to damage a record if dropped on a record.

According to the present invention, danger to either needle or record by careless handling of the tone arm is virtually eliminated. This is accomplished by providing a guard which automatically swings down to a position to support the tone arm with the needle held above the record surface, the guard being automatically swung out of place with rotation of the record so as to lower the needle into playing position. When the tone arm rests on the guard, the needle is so close to the record that neither damage nor loud noise will result from the slight further movement occasioned when the guard swings out of place to lower the needle.

Additional objects and advantages of the invention will become apparent from the following description and from the drawings in which:

Figs. 1, 2, and 3 are fragmentary elevational views of a phonograph showing the tone arm supported respectively, in position upon a rest, in a non-playing position upon the guard which is based upon the disc record, and in its operative playing position;

Fig. 4 is an enlarged fragmentary bottom View of the free end of the tone arm to which one form of the guard of this invention is shown applied, View being taken on the line 4-4 of Fig. 3;

Figs. 5 and 6 which are fragmentary'enlarged vertical sectional views, show the guard of Fig. 4 in two positions;

Fig. '7 is a perspective view of the guard, including the mounting bracket therefor; and

Fig. 8 is a fragmentary View showing in side elevation a modified form of guard.

A preferred form of the invention has been illustrated in accordance with the patent statutes, but, no doubt, other means of using one or more of the inventive concepts herein disclosed will be devised and it is my desire that all of these be covered by the appended claim.

The invention is illustrated in conjunction with a tone arm H and a turntable [2 On which may be positioned a disc record l3, all of which may 1 Claim. (01. 274-23) be conventional. The tone arm I i may carry any form of pick-up cartridge i l secured thereto in any desired manner. The pick-up unit includes aneedle N projecting downwardly and angularly therefrom and, in accordance with this invention, a guard G.

v The guard G may comprise a single piece of wire bent generally to a U-shape as seen best in Figs. 4 and 7. It is shown as pivotally supported at the upper ends of the legs of the U as by means of a bracket it which may be secured to the pickup cartridge Id by screws ii. The bracket it in-- cludes wings I 8 each of which is apertured to receive an inturned end ill of the guard G.

It will be evident that whenever the tone arm is suspended in the air, as upon the rest 2| (see Fig. 1), the guard G will swing downwardly by.

gravity to assume approximately the position shown in Figs. 1, 2 and 5. Should the tone arm be either lowered or dropped, the guard G will remain in approximately this position with respect to the tone arm while it is in the air. The tone arm is conventionally mounted to pivot freely, but it is restrained against longitudinal movementthe only movement that would tend by jerky handling to swing the guard out of its normal hanging position. Accordingly, when the tone arm is lowered toward the record or any other surface, its downward movement will be stopped by the guard.

If the record is not moving, the guard may remain in position and in the illustrated form, the cross wire 22 forming the base of the U is offset rearwardly. In eiTect, each side includes two feet 23 which may be spaced slightly by an arched portion 24. The balance is such that these feet hang approximately in a horizontal plane with one forwardly and one rearwardly of the vertical line through the inward turned ends l9 so that the guard will rest with some stability until the supporting surface moves.

The rotation of the turntable will cause the guard G to swing from the supporting position shown in Figs. 2-and 5 to the non-supporting position shown in Figs. 3 and 6. This will lower the needle gently onto the record. The distance the tone arm drops from the Fig. 2 position to the Fig. 3 position is too short for it to acquire a speed which would cause any damage or even any objectionable jolt. Of course, the shorter the final drop, the more gentle will be the ultimate contact of the needle with the record. It is desirable to have the dimensions such that the cross wire 22 will just pass over the needle with ample clearance to allow for variations in manufacture or other possible irregularities. should not drop over /4 inch.

Even if the record disc is rotating at the time the guard G strikes it, the downward movement of the tone arm will nevertheless be checked so tha the speed at which the needle engages the record will only be that resulting from the drop of the tone arm from the Fig. Zposition to the Fig. 3 position.

It is important that the guard be so constructed as to avoid damage to the record if the tone arm be carelessly lowered to playing position. While the tone arm is too light to deliver a heavy blow, the wire guard is nevertheless sufiiciently resilient and its contact area sufficiently large to afford the necessary protection. The cross wire 22 is substantially flat so that its entire length will rest on the record and furthermore the arching at 24, here shown as somewhat exaggerated, is preferably just high enough to ensure initial contact at the spaced points 23.

If desired, some cushioning may be provided as by slipping one or more sections of small rubber tubing or spaghetti onto the guard to cover the various contact points or feet 23. As an alternative, or in addition, the legs of the guard G may be curved as shown in Fig. 3, for example, to provide increased resiliency, thereby preventing direct longitudinal thrust through the wire legs.

It will be observed from Fig. 6 that as the record continues to rotate, the guard G remains lightly in contact therewith, but the guard is so extremely light that this is entirely unobjectionable. Although the guard might be formed to lie entirely to one side of the needle, I prefer that it occupy the straddling position which is illustrated.

The guard is shown as mounted in place with the aid of screws, but it may be secured by a spring clip engaging either the tone arm or the cartridge. This might be desirable in the case of guards which are sold separately for application to tone arms not originally equipped therewith.

The needle 4 From the foregoing it is seen that I have provided a guard which substantially eliminates any damage to the needle or record disc due to careless handling or dropping of the tone arm. It is extremely simple and inexpensive to manufacture and can easily be applied to conventional tone arms of the present time.

I claim: The combination of a phonograph tone arm including a pick-up needle, a needle guard consist- .ing of a single piece of wire and composed of laterally spaced sides pivotally connected at their upper ends with the tone arm and located at opposite sides of the needle, a substantially straight cross piece located adjacent the lower ends of said sides in spaced relation therewith and adapted to rest upon a phonograph record, and laterally spaced arched portions connecting the said sides with said cross piece and forming pairs of feet located at opposite sides of the guard and arranged to rest upon the phonograph record, said guard being adapted to swing by gravity to a position extending below the needle and adjacent thereto to check the movement of the tone arm as it is dropped or lowered onto the record and adapted to swing under the influence of forward rotation of the record on which it rests whereby the tone arm is lowered until the needle comes to rest on the record.

- COLIN B. DALE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,249,? 20 Christian Dec. 11, 1917 830,689 Valiquet Sept. 11, 1906 1,428,828 Ahearn Sept. 12, 1922 2,214,509 Otto 1- Sept. 10, 1940 2,262,503 Kierulfi Nov. 11, 1941 2,327,094 Catucci Aug. '17, 1943

Images